WO2023227268A1

WO2023227268A1 - Compressed air generating device and method for operating same

Info

Publication number: WO2023227268A1
Application number: PCT/EP2023/056316
Authority: WO
Inventors: Heinrich Diekmeyer; Steffen Jordan; Kevin Pendzich
Original assignee: Zf Cv Systems Global Gmbh
Priority date: 2022-05-23
Filing date: 2023-03-13
Publication date: 2023-11-30
Also published as: DE102022112935A1

Abstract

The invention relates to a compressed air generating device (2.1) comprising a control and regulating device (28), at least one controllable and regulatable electric motor (24), at least one air compressor (16, 18) which can be driven by the electric motor (24), an air inlet (8) via which surrounding air (L) can be suctioned into the at least one air compressor, at least one air cooler (20, 22) which is connected to the outlet of the at least one air compressor, an air dryer (40), the inlet of which is connected to the outlet of the at least one air cooler, a coolant inlet opening (12*) via which a liquid coolant can be supplied to the at least one air cooler and other components of the compressed air generating device, and a coolant outlet opening (14) via which heated coolant can be discharged out of the compressed air generating device. In order to design the compressed air generating device to be as compact as possible and inexpensive to produce, the control and regulating device (28) is designed and arranged such that the control and regulating device can be used to control and regulate the operation of the electric motor (24), a drying operation, and a regeneration operation of the air dryer (40) as well as the operation of a multi-circuit protection valve (50), and coolant can flow through the air cooler (22) first when viewed in the flow direction of the coolant, said air cooler being arranged in front of the air dryer (40) as the last air cooler in the flow direction of the compressed air. The invention also relates to a method for operating said compressed air generating device.

Description

Compressed air generating device and method for operating the same

The invention relates to a compressed air generating device, with a control and regulating device, with at least one controllable and regulatable electric motor, with at least one air compressor that can be driven by the electric motor, with an air inlet via which ambient air can be sucked into the at least one air compressor, with at least one air cooler, which is connected to the output of the at least one air compressor, to an air dryer, the input of which is connected to the output of the at least one air cooler, to a coolant inlet opening, via which a liquid coolant can be supplied to the at least one air cooler and other components of the compressed air generating device, and with a coolant outlet opening through which heated coolant can be removed from the compressed air generating device. The invention also relates to a method for operating such a compressed air generating device.

Electrically driven compressors for generating compressed air in vehicles are already known in various embodiments and are described, for example, in DE 10 2018 139 058 A1, DE 10 2013 003 513 A1 and EP 3 516 218 B1. From EP 3 331 738 B1 a compressed air generating device for a vehicle with a piston compressor and two compression stages is known. The cylinder spaces of the two compression stages are connected to one another by a connecting line through which the compressed air generated in the first compression stage can be fed to the second compression stage. When the piston compressor is in operation, the ambient air pressure in the first compression stage is increased with the help of a counterpressure that builds up in the subsequent connecting line. An intercooler is arranged in the connecting line between the two compression stages and serves to cool the air heated during compression in the first compression stage. The pressure of the compressed air in the connecting line drops.

The intercooler can therefore increase the efficiency of the second compression stage. Furthermore, before or after the first compression stage, additional ones can be used Facilities for processing the air used may be arranged, such as further cooling devices or air drying devices. One disadvantage is that the compressor described is designed as a reciprocating piston compressor, which disadvantageously requires a lubricant. In addition, the design of the cooling system is not described further.

In addition, from DE 10 2004 051 435 B3 a system for generating dry compressed air is known, which has a cooled compressor for sucking in and compressing ambient air. The compressor is followed by a cooler in the direction of flow of the compressed air, which serves to cool the compressed air generated. The cooling effect of the cooler is achieved by means of a fan and water droplets directed onto the surface of the cooler, which evaporate there and thereby remove heat from the cooler and indirectly from the compressed air. The cooler is followed by an air dryer which contains a desiccant that removes moisture from the compressed air and thereby lowers the dew point of this compressed air. The compressed air dried in this way has an air humidity of less than 35% at the outlet of the air dryer, which should be sufficient to protect devices subsequently supplied with this compressed air from corrosion or freezing due to the formation of water ice.

Furthermore, from DE 44 45 972 02 a compressor system for generating dry compressed air is known, in which an air-cooled radiator is used to cool the compressed air generated by a compressor. There is a water separator downstream of the radiator, by means of which water droplets can be removed from the compressed air, which are formed by condensation when the compressed air cools down. Since the compressed air is not yet sufficiently dry to be able to avoid freezing at low temperatures when used in pressure medium consumers, the water separator is followed by an air dryer in which the compressed air is further dried.

In addition, from the applicant's unpublished DE 10 2021 121 424.6, a compressed air generating device is known which has an electric motor which can drive two air compressors arranged in series. During operation of the compressed air generating device, ambient air is generated by means of the first air compressor sucked in and compressed. From there, the pre-compressed compressed air is fed to the second air compressor via a check valve, an intercooler and a switching valve. In the second air compressor, the pre-compressed compressed air is further compressed and then passed on to compressed air consumers via an aftercooler or another switching valve. The intercooler and the aftercooler are cooled using a liquid coolant and are used to cool the compressed air generated by the air compressors. The liquid coolant comes, for example, from a cooling circuit of a vehicle and in the compressed air generating device first supplies a cooling device of the electric motor, then the intercooler and then a cooling device of the first air compressor. From there, the coolant goes to the aftercooler and then to a cooling device of the second air compressor before the coolant is returned to the vehicle's cooling circuit. An air dryer is neither shown nor described in this compressed air generating device.

In addition, a water-cooled and oil-free two-stage air compressor is known from US 2010/0 303 658 A1, which has a water-cooled intercooler which is arranged between a first air compressor and a second air compressor with regard to the air flow. The air compressed by the first air compressor is cooled by the intercooler, and the air compressed by the second air compressor is cooled by an aftercooler whose cooling water inlet is hydraulically connected to the cooling water outlet of the intercooler.

Finally, from DE 11 2015 006 955 T5 a compressed air supply system for locomotives and a method for operating the same are known, in which the air sucked in and compressed by a compressor is cooled in an air cooler and then fed to a first compressed air storage. From this first compressed air reservoir, the compressed air travels via a check valve that closes in the return flow direction to a prefilter which has a drainage valve. After separating liquid and aerosolized water from the compressed air in the pre-filter, the compressed air goes to an air dryer. A temperature sensor arranged at the air flow inlet of the air dryer or in its immediate vicinity is connected to a control unit via a sensor line. The temperature sensor can display the actual Measure the temperature of the compressed air flowing into the air dryer and make this measured value available to the control unit. The controller can calculate an appropriate purge cycle time for the drain valve based on the saturation partial pressure of water vapor at the measured actual temperature of the compressed air and control its operation to remove the water accumulated in the pre-filter.

The desiccant of the air dryer of such generic compressed air generating devices must also be repeatedly freed from the moisture that has accumulated there, because if the moisture absorption capacity of its desiccant is saturated, it is no longer able to work in accordance with the task. In order to remove this moisture from the air dryer, it is known to pass dry compressed air generated by the compressed air generating device and stored in a pressure medium storage back through the air dryer in a so-called regeneration process. Here, the dry compressed air absorbs moisture from the desiccant of the air dryer and transports it outside into the environment of the compressed air generating device. Since these regeneration processes consume dried compressed air, which is actually required in a motor vehicle, for example, for the actuation of, for example, brake actuators and/or air bellows, additional operating times of the compressor are necessary in order to also stock up on sufficient compressed air for the regeneration processes. However, this is associated with additional energy consumption, which increases the operating costs of a motor vehicle, for example, and ultimately also releases environmentally harmful CO2 into the atmosphere through the generation of electrical energy for the electric motor.

Against this background, the invention is based on the object of presenting a compressed air generating device with a compressor, a liquid cooling system and an air dryer, which is compact and can be produced inexpensively. In addition, this compressed air generating device should enable a lower consumption of dried compressed air during regeneration of a desiccant of the air dryer than with known compressed air generating devices. In addition, the volume of regeneration compressed air that is expected to be required for the respective regeneration of the drying agent should be able to be determined using a method. This problem is solved with a compressed air generating device which has the features of claim 1. An independent method claim defines a method for operating such a compressed air generating device. Advantageous refinements and further developments are mentioned in the respectively assigned dependent claims.

Accordingly, the invention initially relates to a compressed air generating device, with a control and regulating device, with at least one controllable and regulatable electric motor, with at least one air compressor that can be driven by the electric motor, with an air inlet via which ambient air can be sucked into the at least one air compressor, with at least one Air cooler, which is connected to the output of the at least one air compressor, with an air dryer, the input of which is connected to the output of the at least one air cooler, with a coolant inlet opening, via which a liquid coolant can be supplied to the at least one air cooler and other components of the compressed air generating device, and with a coolant outlet opening through which heated coolant can be removed from the compressed air generating device.

In order to solve the task relating to the device, it is provided in this compressed air generating device that the control and regulating device is designed and arranged in such a way that the operation of the electric motor, a drying operation and a regeneration operation of the air dryer, as well as the operation of a multi-circuit protection valve can be controlled and regulated , and that the air cooler, which is arranged as the last air cooler in front of the air dryer in the flow direction of the compressed air, is the first to be flowed through by the coolant when viewed in the flow direction of the coolant.

Accordingly, in a departure from the previously known designs, an aftercooler is first flowed through by the still comparatively cold liquid coolant, which is arranged directly in front of the air dryer when viewed in the flow direction of the compressed air. This cools the compressed air as much as possible, so that some of the humidity contained in this compressed air precipitates in the form of small drops of water before it reaches the air dryer. This water will then for example, removed from the compressed air by a water separator in the aftercooler before it reaches the air dryer. A small amount of condensed water droplets can also be carried along by the comparatively strongly cooled compressed air via a short compressed air line to the air dryer, in the inlet collection area of which these water droplets collect and are removed during the next regeneration process with the regeneration compressed air flowing out of the air dryer. Because a comparatively large amount of moisture is removed from the compressed air before the air dryer reaches the drying agent, the air dryer is then required less to dry the compressed air. As a result, a regeneration process that consumes dried compressed air needs to be carried out on the air dryer less frequently.

The fact that, according to the invention, the control and regulating device is designed and arranged in such a way that the operation of the electric motor, a drying operation and a regeneration operation of the air dryer, as well as the operation of a multi-circuit protection valve can be controlled and regulated, is a separate control and regulating device for controlling and regulating the electric motor or a separate control and regulating device for at least indirectly controlling and regulating a multi-circuit protection valve is not necessary. This saves manufacturing costs and installation space.

According to an advantageous development, the amount of liquid coolant passed every second through the coolable components of the compressed air generating device can be adjusted by means of a controllable coolant pump, which is controllably connected to the control and regulating device.

In a further development of the compressed air generating device, the arrangement of at least one temperature sensor is provided, which is arranged in front of the coolant inlet and/or behind the coolant outlet of that air cooler for measuring the coolant temperature, and which is placed in the flow direction of the compressed air as the last air cooler in front of the air dryer, for example on a coolant line is. This temperature sensor is connected to the control and regulation device via a data or sensor line. The data or sensor line can be a CAN bus line. By arranging such a temperature sensor, the control and regulating device can be used to calculate how much the compressed air coming from the air compressor cools in the air cooler and thus water is separated from the compressed air before it reaches the air dryer. Using this knowledge, an optimally small volume of dry compressed air can be passed through the air dryer during a regeneration process for drying the desiccant. This minimizes the consumption of dry compressed air and reduces the number and/or duration of regeneration processes on the air dryer to a minimum.

The design features proposed by the invention can be applied to differently configured compressed air generating devices. Such a compressed air generating device can have only one or more compressor stages, which can be driven, for example, by only one electric motor or by one electric motor each. The design of the compression stages and the number of air coolers are also not specified with regard to the use of the invention.

For example, the invention can be used in a compressed air generating device which has an electric motor and two air compressors that can be driven by this and operate one after the other. This compressed air generating device also has an air inlet through which ambient air can be sucked in by means of the first air compressor. There is also a first air cooler designed and arranged as an intercooler and a second air cooler designed and arranged as an aftercooler. Here, the inlet of the intercooler is pneumatically connected to the outlet of the first air compressor, the outlet of the intercooler is pneumatically connected to the inlet of the second air compressor, and the outlet of the second air compressor is pneumatically connected to the inlet of the aftercooler. There is also an air dryer whose inlet is pneumatically connected to the outlet of the aftercooler. There is also a coolant inlet opening through which a liquid coolant can be supplied to the intercooler as well as the aftercooler and other components of the compressed air generating device. There is also a coolant outlet opening through which heated coolant can be removed. According to the invention, in this compressed air generating device it is also provided that the aftercooler, which is arranged as the last air cooler in front of the air dryer in the flow direction of the compressed air, is the first to be flowed through by the coolant when viewed in the flow direction of the coolant, that at least one temperature sensor is present, which with the control and regulating device is connected via a data or sensor line, that the temperature sensor for measuring the coolant temperature is arranged in front of the coolant inlet or behind the coolant outlet of the aftercooler, and that the control and regulating device is designed in such a way that with this in addition to the Operation of the electric motor, a drying operation and a regeneration operation of the air dryer as well as the operation of a multi-circuit protection valve can be controlled and regulated.

With regard to the further specific arrangement of the at least one temperature sensor, it can be provided that it is arranged in front of the coolant inlet opening of the compressed air generating device for measuring the coolant temperature. In this case, a temperature sensor can be used particularly cost-effectively, which is anyway arranged on an external cooling device of a motor vehicle, in order to determine the temperature of the coolant at the output of this external cooling device and to communicate this to the control and regulating device of the motor vehicle. However, if the line length for transporting the coolant from this external cooling device to the compressed air generating device is comparatively long, such an arrangement can be unfavorable because the coolant can cool or heat up in an uncontrolled manner on the way to the coolant inlet of the compressed air generating device.

For this reason, it can be provided that the temperature sensor for measuring the coolant temperature is arranged directly in front of the coolant inlet of the aftercooler, which is arranged as the last air cooler in front of the air dryer in the direction of flow of the compressed air. This gives you particularly reliable measurements. However, it can also be provided that the temperature sensor for measuring the coolant temperature is arranged as the next component behind the coolant outlet of the aftercooler, which is arranged as the last air cooler in front of the air dryer in the direction of flow of the compressed air. This location of the temperature sensor can be directly at the coolant outlet of the aftercooler, or if the installation space there does not allow this, at the closest possible location in the flow direction of the coolant behind the coolant outlet of the aftercooler.

It can also be provided that a temperature sensor is arranged both at the coolant inlet and at the coolant outlet of the aftercooler, which are connected to the control and regulating device in terms of signals. Using the temperature values measured by these two temperature sensors, a temperature difference can be determined in the control and regulating device, which is a measure of the cooling of the compressed air in the aftercooler. From this you can at least estimate how much water has condensed out of the compressed air as it flows through the aftercooler. If necessary, an additional temperature sensor is necessary for this, with which the temperature of the compressed air at the compressed air inlet of the aftercooler can be measured.

According to another development of the subject matter of the invention, it can be provided that the at least one electric motor, an inverter influencing the operation of the electric motor, the two air compressors, the intercooler, the aftercooler, the air dryer, the multi-circuit protection valve, which connects the output of the air dryer with at least one external compressed air storage and external compressed air consumers pneumatically connects, as well as a silencer interacting, but are arranged separately in relation to each other.

Alternatively, it can be provided that the at least one electric motor, an inverter influencing the operation of the electric motor, the two air compressors, the intercooler, the aftercooler, the air dryer, the multi-circuit protection valve, which pneumatically connects the output of the air dryer with at least one external compressed air storage and external compressed air consumers connects, and a silencer is arranged in or on a common housing. In the two construction variants described, the device components mentioned are connected to one another in a suitable manner via the electrical, pneumatic and hydraulic connecting lines mentioned and possibly arranged in the housing. As a result, the compressed air generating device is extremely compact, easy to assemble during production and easy to attach to a motor vehicle, for example a commercial vehicle.

In this context, it can further be provided that the control and regulating device is arranged separately or in or on the housing, that the control and regulating device is connected via a first control line to the inverter for controlling and regulating the electric motor, that the control and control device is connected via a second control line to a 3/2-way solenoid switching valve, which is used to open or close a regeneration line that pneumatically at least indirectly connects the compressed air storage and the air dryer, and that the control and regulating device is connected to the multi-circuit protection valve via a sensor line is.

Due to the additional integration of the control and regulating device, the 3/2-way solenoid switching valve as well as the associated control lines and the regeneration line into the housing of the compressed air generating device, this contains further components assigned to the compressed air generating device, which makes the entire system even easier to handle and easier to connect to the motor vehicle . Therefore, if one of its components malfunctions, such a compressed air generating device can easily be removed as a whole from a commercial vehicle and sent to a repair point, while a new compressed air generating device is quickly and easily installed on the motor vehicle. Since a compressed air generating device is an operationally necessary device, especially in commercial vehicles, the procedure described avoids lengthy repairs and the commercial vehicle can be put back into use quickly.

A particularly compact variant of a compressed air generating device according to the invention can be achieved in that the control and Control device is structurally integrated in the inverter or in the multi-circuit protection valve.

Alternatively, in a compressed air generating device having the features of the invention, it can be provided that the control and regulating device mentioned is the central control and regulating device of a vehicle. This saves additional costs and installation space for the provision of the device's own control and regulating device, but sensor and control lines for the operation of the compressed air generating device must be available from it to the control and regulating device of the vehicle.

In order to further improve the repairability of the compressed air generating device and to enable quick repairs, according to another development of the compressed air generating device it can be provided that it is constructed from several modules, which, together with the associated pneumatic, hydraulic and electrical lines, are arranged in or on a common housing are.

Accordingly, it can be provided that a compressor module, a compressed air cooling module, a dryer module and a silencer module together with associated pneumatic, hydraulic and electrical lines are arranged in or on the housing of the compressed air generating device, the compressor module containing the electric motor Inverter, which has both air compressors and the control and regulating device, the compressed air cooling module having the intercooler and the aftercooler, the dryer module having the air dryer and the multi-circuit protection valve, the silencer module having the silencer with a sound-absorbing material, and in which the silencer module has at least one regeneration air outlet opening for discharging regeneration compressed air into the environment.

The sound-absorbing material is designed in such a way that it also absorbs water droplets separated by the air dryer and also carries splash water into the silencer to a water outlet of the Silencer module can conduct. In certain applications, the integration of a solitary silencer module can be dispensed with.

Regarding the modular structure of a compressed air generating device having the features of the invention, it can be provided that the compressor module, the dryer module and the silencer module are arranged one behind the other in this order, and that the at least one air cooler is in the silencer or in the silencer module is integrated.

With regard to the air cooler, in the design just mentioned it can be provided that only the intercooler or only the aftercooler is integrated in the installation space of the silencer. However, it is preferably provided that both the intercooler and the aftercooler are integrated in the silencer. Of course, in the variants just mentioned, the compressed air lines, coolant lines and sensor lines connected to the at least one air cooler are also arranged in the silencer or silencer module.

The integration of the air coolers mentioned in the silencer creates several advantages, because the intercooler, the aftercooler or both air coolers are supplied with compressed air via pneumatic lines, which was heated by compression in the compressor stages. The pneumatic lines heat up due to the warm compressed air and transfer their heat to the sound-absorbing material of the silencer. If water is deposited on the sound-absorbing material, it is heated by the waste heat from the pneumatic lines and evaporates into water vapor, which is ultimately discharged from the silencer into the ambient air during the next regeneration process on the air dryer together with regeneration compressed air.

If necessary, such a silencer does not require a water outlet opening to save money in order to drain away condensation that accumulates in the silencer or splash water that has penetrated into it. Finally, installation space is saved if the at least one air cooler is integrated into the installation space of the sound-absorbing material of the silencer. The sound-absorbing material arranged in this silencer can be formed as a package be, which is adapted to the dimensions and geometry of the at least one air cooler and can be replaced if necessary.

According to a further development of the invention, it can therefore be provided that the silencer is designed without a water outlet opening. To further optimize the evaporation of condensation water in the silencer, it is then provided that a compressed air line leading from the at least one compressor to the at least one air cooler has a heating coil-shaped section in a sump area of the silencer. The sound-absorbing material of the silencer is arranged in such a way that it can be heated during operation of the compressed air generating device at least on the heating coil-shaped section of the compressed air line mentioned.

According to another development of the compressed air generating device in question here, it is initially provided that the silencer is designed without a water outlet opening. It is further provided that the coolant line leading from the external cooling device to the at least one air cooler is guided through a sump area of the silencer, and that this coolant line is designed and arranged at least in this sump area of the silencer in such a way that during operation of the compressed air generating device, the coolant line provides the sound-absorbing Material of the silencer can heat up at an ambient temperature below the coolant temperature.

An even more detailed design of the compressed air generating device provides that the intercooler and the aftercooler are integrated into the silencer, that the first air compressor is connected to the intercooler via a first compressed air line, that the intercooler is connected to the second air compressor via a second compressed air line, that the second air compressor is connected to the aftercooler via a third compressed air line, that the aftercooler is connected to the air dryer via a fourth compressed air line, and that the four compressed air lines mentioned are designed and arranged in the silencer in such a way that by means of the warm compressed air guided through these compressed air lines The water that has accumulated in the silencer can be heated up to such an extent that this water evaporates and can be removed from the silencer. Another variant of the compressed air generating device having the features of the invention is equipped with at least one electric motor, with which at least one air compressor can be driven, and which has an air inlet through which ambient air can be sucked in by means of the air compressor. This compressed air generating device has at least one air cooler in which the air compressed by the air compressor can be cooled. There is also an air dryer, the inlet of which is pneumatically connected to the outlet of the at least one air cooler. Furthermore, a coolant inlet opening is formed, via which a liquid coolant can be supplied to the air cooler. There is also a coolant outlet opening through which heated coolant can be removed.

This compressed air generating device is characterized in that the silencer has at least one regeneration air outlet opening for discharging regeneration exhaust air guided through it into the environment, that this at least one regeneration air outlet opening when the desiccant of the air dryer is not regenerated as an air inlet for sucking in ambient air which serves at least one air compressor, and that the ambient air sucked in by the silencer can be conducted downstream behind the silencer through an intake air line to the at least one air compressor.

A further development of the compressed air generating device derived from this has the following: at least one electric motor, two air compressors that can be driven by the electric motor and act one after the other, an air inlet through which ambient air can be sucked in by means of the first air compressor, and an intercooler and an aftercooler, the inlet of the intercooler also is pneumatically connected to the output of the first air compressor, wherein the output of the intercooler is pneumatically connected to the input of the second air compressor, and wherein the output of the second air compressor is pneumatically connected to the input of the aftercooler, further comprising an air dryer, the input of which is connected to the output of the aftercooler, as well as with a coolant inlet opening, via which a liquid coolant can be supplied to the intercooler and the aftercooler, and with a coolant outlet opening, via which heated coolant can be removed. This further developed compressed air generating device is also characterized in that the silencer has at least one regeneration air outlet opening for discharging regeneration exhaust air guided through it into the environment, and that the at least one regeneration air outlet opening acts as an air inlet for sucking in ambient air when the desiccant of the air dryer is not regenerated serves towards the first air compressor, and that the ambient air sucked in through the silencer can be conducted downstream behind the silencer through an intake air line to the first air compressor.

In order to avoid undesirable contamination or heavy splash water loading of the silencer via the combined effective inlet and outlet for the ambient air to be sucked in as well as for the removal of moisture-carrying regeneration compressed air, according to another development of the compressed air generating device, it is provided that a separator for separating out is provided in front of or in the silencer Water and particles are arranged, which are designed and arranged in such a way that the ambient air sucked in through the at least one regeneration air outlet opening, which also serves as an air inlet, can be freed from entrained water droplets and particles. Such a separator can be designed, for example, as a cyclone separator, in which ambient air sucked in is directed in a circular or spiral movement.

A separate air filter with a conventional air filter material is therefore not required in this design, because the sound-absorbing material arranged in the silencer also performs the task of an air filter material.

For those applications in which the sound-absorbing material arranged in the silencer is too coarse-meshed to be able to adequately perform an air filter function, it can be provided that a conventional air filter is arranged at the inlet of the intake line for ambient air. In this embodiment, the inlet of the intake line for ambient air is connected to an opening in the silencer that serves as an outlet for sucked-in ambient air. Another compressed air generating device having the features of the invention also has at least one electric motor with which at least one air compressor can be driven. There is also an air inlet through which ambient air can be sucked in using the air compressor. There is also at least one air cooler in which the air compressed by the air compressor can be cooled. An air dryer is also arranged, the inlet of which is pneumatically connected to the outlet of the at least one air cooler. Furthermore, a coolant inlet opening is formed on the compressed air generating device, via which a liquid coolant can be supplied to the air cooler. Heated coolant can be returned to the external cooling device via a coolant outlet opening that is also present. In addition, a multi-circuit protection valve is arranged, which pneumatically connects the outlet of the air dryer to at least one external compressed air storage and external compressed air consumers. There is also a control and regulating device which is connected to the multi-circuit protection valve and the sensors arranged there via at least one sensor line.

In order to make this compressed air generating device independent of a specific, possibly vehicle-specific, multi-circuit protection valve, it is provided according to a further development in question here that the multi-circuit protection valve can be separated from the other components of the compressed air generating device and can be operated remotely from these components, that the control and regulating device as well as that Multi-circuit protection valve have electrical connecting means which are releasably connected to one another via at least one flexible electrical line, and that the multi-circuit protection valve has pneumatic connecting means which are at least indirectly releasably connected to the outlet of the air dryer via at least one flexible pneumatic line.

The invention also relates to further development of the variant of the compressed air generating device just described, with at least one electric motor, with two air compressors that can be driven by the electric motor and act one after the other, with an air inlet through which ambient air can be sucked in by means of the first air compressor, with an intercooler and an aftercooler, whereby the inlet of the intercooler is pneumatically connected to the outlet of the first air compressor is, wherein the output of the intercooler is pneumatically connected to the input of the second air compressor, and wherein the output of the second air compressor is pneumatically connected to the input of the aftercooler, with an air dryer, the input of which is connected to the output of the aftercooler, with a coolant inlet opening , via which a liquid coolant can be supplied to the intercooler and the aftercooler, with a coolant outlet opening through which heated coolant can be removed, with a multi-circuit protection valve, which pneumatically connects the output of the air dryer with at least one external compressed air storage and external compressed air consumers, and with a control and control device, which is connected to the multi-circuit protection valve and sensors arranged there via at least one sensor line.

In this variant of the compressed air generating device, the invention provides that the multi-circuit protection valve can be separated from the other components of the compressed air generating device and can be operated remotely from these components, that the control and regulating device and the multi-circuit protection valve have electrical connecting means which can be detached from one another via at least one flexible electrical sensor line are connected, and that the multi-circuit protection valve has pneumatic connecting means which are at least indirectly releasably connected to the outlet of the air dryer via at least one flexible pneumatic line.

In a further embodiment of the compressed air generating device just described, it is provided that a dryer module having the air dryer has at least one electrical plug socket and at least one pneumatic plug socket, so that the electrical plug socket of the dryer module is connected to an electrical plug socket on the control and regulating device via the sensor line is that an electrical plug of an electrical connecting line can be releasably plugged into the electrical plug socket of the dryer module, that this electrical connecting cable has a second plug which can be releasably plugged into an electrical plug socket of the multi-circuit protection valve, that the pneumatic plug socket of the dryer module with the fifth compressed air line is pneumatically connected, through which dried compressed air coming from the air dryer can be conducted into this pneumatic socket of the dryer module a plug of a pneumatic connecting line can be detachably inserted, and that the pneumatic connecting line has a second plug, which can be detachably inserted into a pneumatic socket of the multi-circuit protection valve.

In order to make a compressed air generating device having the features of the invention particularly compact, i.e. to save space, it has at least one electric motor with which at least one air compressor can be driven. This at least one air compressor can suck in ambient air via an air inlet. Furthermore, there is at least one air cooler in which the air compressed by the at least one air compressor can be cooled. An air dryer is also arranged, with which compressed air cooled by the air cooler can be dried. In addition, this compressed air generating device has a coolant inlet opening through which a liquid coolant can be supplied to the air cooler. Heated coolant can be discharged via a coolant outlet opening that is also designed. This compressed air generating device also includes a multi-circuit protection valve, which pneumatically connects the output of the air dryer to at least one external compressed air storage and to external compressed air consumers, as well as an inverter, which is used to control and regulate the electric motor. Finally, there is a control and regulating device which is connected to the multi-circuit protection valve and sensors arranged there via at least one sensor line and to the inverter via at least one control line.

This compressed air generating device has now been further developed in such a way that the control and regulating device is an integral part of the inverter.

As a result, the already mentioned compressor module in particular is designed to be particularly compact, in which the at least one electric motor, the inverter, the two air compressors and the intercooler assigned to these air compressors are arranged. The control and regulating device is therefore structurally accommodated in a housing of the inverter or forms a structural unit with it, so that the control line from the control and regulating device to the electronics of the inverter is also optimally short. Of course, the construction described can also be reversed in terms of language and construction, namely that the inverter is an integral part of the control and regulation device. In a further embodiment of this integration of the control and regulating device, the compressed air generating device can also be designed as follows:

Having at least one electric motor, two air compressors that can be driven by the electric motor and act one after the other, an air inlet through which ambient air can be sucked in by means of the first air compressor, an intercooler and an aftercooler, the inlet of the intercooler being pneumatically connected to the outlet of the first air compressor, wherein the output of the intercooler is pneumatically connected to the input of the second air compressor, and wherein the output of the second air compressor is pneumatically connected to the input of the aftercooler, and further comprising an air dryer whose input is connected to the output of the aftercooler, a coolant inlet opening, via which can be supplied with a liquid coolant to the intercooler and the aftercooler, a coolant outlet opening through which heated coolant can be removed, a multi-circuit protection valve which pneumatically connects the output of the air dryer to at least one external compressed air reservoir and to external compressed air consumers, an inverter which is used for control and regulation of the electric motor, as well as a control and regulating device, which is connected via at least one sensor line to the multi-circuit protection valve and sensors arranged there and to the inverter via at least one control line.

In this development of the compressed air generating device it is provided that the control and regulating device with the advantages mentioned is also an integral part of the inverter.

The control and regulating device can also be integrated into the multi-circuit protection valve. According to this further development, we are dealing here with a compressed air generating device, having at least one electric motor, two air compressors that can be driven by the electric motor and act one after the other, an air inlet through which ambient air can be sucked in by means of the first air compressor, an intermediate cooler and an aftercooler, the inlet of the intercooler is pneumatically connected to the output of the first air compressor, wherein the output of the intercooler is pneumatically connected to the input of the second air compressor, and wherein the output of the second air compressor is connected to is pneumatically connected to the inlet of the aftercooler, as well as with an air dryer, the inlet of which is connected to the outlet of the aftercooler, a coolant inlet opening, via which a liquid coolant can be supplied to the intercooler and the aftercooler, a coolant outlet opening, via which heated coolant can be removed Multi-circuit protection valve, which pneumatically connects the output of the air dryer with at least one external compressed air storage and with external compressed air consumers, an inverter, which is used to control and regulate the electric motor, and a control and regulating device, which has at least one sensor line with sensors of the multi-circuit protection valve and with the Inverter is connected via at least one control line. According to this development, as already mentioned, it is provided that the control and regulating device is an integral part of the multi-circuit protection valve.

Alternatively, it can be provided that in the compressed air generating device just described, the features of which are not repeated here, the control and regulating device is not an integral part of the multi-circuit protection valve but rather an integral part of a, preferably central, vehicle control device.

The compressed air generating device with the features of the invention can therefore be constructed in detail in such a way that the air dryer can be optimally operated both for drying the compressed air and for regeneration, i.e. for dehumidifying its desiccant. For this purpose, which will be explained in detail using an exemplary embodiment, it is preferably provided that the outlet of the air dryer is connected to a fifth compressed air line via a first check valve that closes in the direction of the air dryer, that this fifth compressed air line is connected via the mentioned multi-circuit protection valve to the at least one compressed air reservoir and to compressed air consumers that a regeneration compressed air inlet of the air dryer is connected to the output of a 3/2-way solenoid switching valve via a second check valve opening in the direction of the regeneration compressed air inlet, an orifice and a first line branch, that the input of this 3/2-way solenoid switching valve is connected to the fifth compressed air line via a regeneration line, so that when the 3/2-way solenoid switching valve is activated, the air dryer is supplied via this 3/2-way Dry compressed air can be supplied as regeneration compressed air to the first line branch, the orifice and the first check valve, and that regeneration compressed air can also be supplied to the pneumatic control input of a 2/2-way switching valve via a second line branch when the 3/2-way solenoid switching valve is actuated, which is assigned to a regeneration air outlet of the air dryer.

A regeneration process on the air dryer is therefore initiated by the control and regulation device and is largely controlled using the 3/2-way solenoid switching valve. By means of the 3/2-way solenoid switching valve, dry regeneration compressed air is directed to the air dryer, and at the same time a control pressure is fed to a control pressure input of the pneumatic 2/2-way switching valve to open a regeneration air outlet of the air dryer. This control pressure is generated by a small portion of the regeneration compressed air, most of which comes from the compressed air storage and is passed into the air dryer for drying the desiccant there.

Another development provides that the pressure-controlled 2/2-way switching valve is assigned to a collecting area of the air dryer, with the pneumatic control input of this 2/2-way switching valve via a second line branch with the output of the 3/2-way solenoid switching valve connected is. This 2/2-way switching valve is designed in such a way that it is closed when not actuated. The 2/2-way switching valve can also be switched from its closed position to its open position by means of regeneration compressed air supplied to the air dryer and via the second line branch. When the 2/2-way switching valve is open, dry regeneration compressed air can be passed through the desiccant of the air dryer in a regeneration compressed air stream. After flowing through the drying agent, the regeneration compressed air can be directed into the collecting area of the air dryer and can entrain any condensed water that has accumulated there and remove it from it via at least one regeneration air outlet on the air dryer.

In addition, the compressed air generating device preferably has a further temperature sensor by means of which the ambient temperature can be measured. This additional temperature sensor is also connected to the control and control via a data or sensor line Control device connected. If a data line is used, it can be a CAN bus line.

The invention also relates to a method for operating a compressed air generating device with the features described. According to the method, compressed air is cooled in at least one air cooler by means of the at least one air compressor. The cooled compressed air is then fed to an air dryer and dried there in order to then be directed to compressed air consumers and/or at least one compressed air storage. During a regeneration operation of the compressed air generating device, in order to regenerate a desiccant arranged in the air dryer, dry compressed air to the extent of the necessary regeneration compressed air volume is passed through the desiccant and then discharged into the environment.

It is provided here that the regeneration compressed air volume required for the regeneration of the desiccant is calculated at least as a function of the temperature that the coolant has before and/or after it flows through the air cooler that is arranged as the last air cooler in front of the air dryer, and that this is then done in such a way A certain regeneration compressed air volume of dry compressed air is passed through the air dryer.

Since the amount of water that the compressed air carries as air humidity after passing through the last air cooler to the air dryer depends on the compressed air temperature there, it may initially seem disadvantageous not to base the regeneration compressed air volume necessary for regeneration operation of the compressed air generating device on the basis of a direct measurement Determine the temperature of the compressed air stream in front of the air dryer.

However, the procedure presented here has the advantage that no additional temperature sensor is necessary to obtain information about what temperature the compressed air has before it reaches the air dryer and what water content in the form of air humidity this compressed air carries with it. As already explained above, every motor vehicle today has one Liquid cooling system measures the coolant temperature after leaving its radiator using a temperature sensor and its measured values are made available in the motor vehicle for a variety of purposes, for example via a CAN data bus. Knowing the temperature of the coolant directly after leaving the vehicle radiator or immediately before the air cooler mentioned, the temperature of the compressed air after leaving this air cooler can be inferred indirectly without requiring a separate temperature sensor.

The operation of the compressed air generating device and in particular the supply of the coolant are then regulated so that the cooling effect of the last air cooler before the air dryer is maximum. As a result, the compressed air is cooled to the maximum in front of the air dryer, as a result of which the compressed air only contains comparatively little moisture that puts a strain on the air dryer. As a result, the desiccant of the air dryer must be regenerated less frequently or with less regeneration compressed air volume.

In a further embodiment of the method, it is provided that the coolant temperature is measured in front of the coolant inlet opening of the compressed air generating device by means of a first temperature sensor, and that the regeneration compressed air volume required for drying the desiccant in the air dryer is controlled and/or as a function of the measured coolant temperature during a later regeneration process is passed through the air dryer in a controlled manner.

Alternatively, it can be provided that by means of a second temperature sensor in this list, the coolant temperature is measured directly in front of the coolant inlet of the air cooler, which is arranged as the last air cooler in front of the air dryer in the flow direction of the compressed air, and that this is for drying the desiccant in the air dryer The respectively required regeneration compressed air volume is passed through the air dryer in a controlled and/or regulated manner depending on the measured coolant temperature during a later regeneration process. Furthermore, it can be provided that, by means of a third temperature sensor, the coolant temperature is measured behind the coolant outlet of the air cooler, which is arranged as the last air cooler in front of the air dryer in the direction of flow of the compressed air, and that the volume of regeneration compressed air required for drying the desiccant in the air dryer depends on the measured coolant temperature is controlled and/or regulated through the air dryer during a later regeneration process.

Another possibility for determining an optimally sufficient volume of regeneration compressed air for drying the desiccant of the air dryer provides that the temperature of an inverter used to control and regulate the electric motor is measured and that the measured temperature of the inverter is used to calculate the coolant temperature in the air cooler which is arranged as the last air cooler in front of the air dryer in the direction of flow of the compressed air, and that the regeneration compressed air volume required for drying the desiccant in the air dryer is passed through the air dryer in a controlled and / or regulated manner depending on the coolant temperature determined in this way.

The temperature of its electronics can be used as the temperature of the inverter. With this method variant, the arrangement of a temperature sensor in the area of the coolant lines and/or the air cooler mentioned can be dispensed with in a cost-saving manner.

According to a further specialization of the method, the following method steps can be provided: a) sucking in ambient air by means of the first air compressor, b) pre-compressing the sucked-in ambient air in the first air compressor to a first air pressure value, c) cooling an intercooler with a liquid coolant, d) Cooling the pre-compressed compressed air in the intercooler, e) further compressing the compressed air to a second, higher pressure value using a second air compressor, f) cooling an aftercooler with the liquid coolant, the aftercooler being the first air cooler, viewed in the flow direction of the coolant, being reached hydraulically by the coolant, g) cooling the compressed air further compressed in the second air compressor in the aftercooler, h) drying the cooled compressed air in an air dryer, i) forwarding the cooled and dried compressed air to compressed air consumers and/or to at least one compressed air storage.

These process steps make it clear that the compressed air that has left the second air compressor is cooled as it flows through the aftercooler to the extent that the freshly supplied liquid coolant allows. For this purpose, it is provided that the liquid coolant is not first directed to a cooling device of the electric motor or to the intercooler in order to cool it during operation, as in the compressed air generating device according to DE 10 2039 139 424.6. In the compressed air generating device presented here, the coolant is first directed to the aftercooler in order to cool it and, as a result, the compressed air as much as possible. This makes it possible according to the method to cool the compressed air generated so much before it reaches the air dryer that as much moisture as possible is separated and drained away from the compressed air.

In order to also cool other components of the compressed air generating device with the liquid coolant, the following further process steps are provided in addition to the method mentioned: j) forwarding the liquid coolant from the aftercooler to the intercooler, k) forwarding the liquid coolant from the intercooler to a cooling device of the electric motor, l) forwarding the liquid coolant from the cooling device of the electric motor to a cooling device of the second air compressor, m) forwarding the liquid coolant from the cooling device of the second air compressor to a cooling device of the inverter, n) forwarding the liquid coolant from the cooling device of the inverter to a cooling device of the first air compressor, o) forwarding the liquid coolant from the cooling device of the first air compressor to an external cooling device.

In addition to guiding the coolant, especially first to the aftercooler, and guiding the compressed air in the compressed air generating device, the regeneration of the drying agent of the air dryer is particularly important. During this regeneration, the drying agent, which has removed atmospheric moisture from the supplied compressed air in previous drying processes and has now greatly reduced its drying ability, is flowed through in the opposite direction by temporarily stored dry compressed air. The compressed air takes water from the desiccant and flows loaded with it out of the air dryer into the environment. The frequency with which such regeneration processes must be carried out and the volume of compressed air required for these regeneration processes influence the need for compressed air to be generated by the compressed air generating device when a vehicle is operating. Since during the cooling of the compressed air described above, water is already separated from the compressed air in the aftercooler, this arrives as a film of water or as small droplets with the compressed air directed to the air dryer into its entrance area, from which it is discharged into the environment before reaching the desiccant.

However, it can just as easily be provided that the time interval between two regeneration processes for drying the desiccant of the air dryer is controlled and/or regulated depending on the temperature of the coolant which the coolant has at the outlet of the external cooling device or at the inlet of the aftercooler.

Since the temperature of the coolant is decisive for how much water has already condensed out of the compressed air supplied to the aftercooler, a comparatively low coolant temperature causes a comparatively large separation of water from the compressed air already at the aftercooler, which is drained from there. As a result, the desiccant of the air dryer is less heavily loaded, so that the regeneration compressed air volume can be lower or, for example, the time interval between two regeneration processes can be greater than at a comparatively high coolant temperature. The ambient temperature of a vehicle must also be taken into account when carrying out regeneration processes of the type described, because the compressed air stored in a compressed air reservoir takes on the ambient temperature over the wall of the compressed air reservoir after some time. Since the compressed air stored in this compressed air storage is also used for the regeneration of the desiccant in the air dryer and the compressed air temperature determines the water storage capacity of the regeneration compressed air, knowledge of the ambient temperature is important for determining the necessary regeneration compressed air volume.

Therefore, in the method in which previously dried and temporarily stored compressed air is passed through the air dryer as regeneration compressed air in the opposite direction to regenerate a desiccant arranged in the air dryer, it can be provided that the volume of regeneration compressed air required for drying the desiccant also depends on the average ambient temperature is controlled and/or regulated.

It can also be provided in this method that the time interval between two regeneration processes for drying the desiccant of the air dryer is controlled and/or regulated as a function of the average ambient temperature. The average value of the ambient temperature can be determined over a predetermined period of time.

For example, if both the ambient temperature and the coolant temperature change quickly due to the current driving situation and/or rapidly changing environmental conditions, it can be provided that the regeneration compressed air volume required for drying the desiccant or the duration and/or frequency of the regeneration processes in Depending on the difference between the ambient temperature and the coolant temperature is controlled and regulated during a later regeneration process.

With unregulated control of the regeneration of the desiccant

According to another development of the method, the air dryer is used to operate the presented compressed air generating device provided that a maximum high temperature value of the coolant to be expected during operation of the compressed air generating device is determined, that this value of the coolant temperature serves as the basis for determining a maximum regeneration compressed air volume, and that a related regeneration process for the desiccant is carried out with this maximum regeneration compressed air volume.

For a better understanding of the invention, a drawing is attached to the description, which shows some exemplary embodiments. Shown in this drawing

Fig. 1 is a schematic representation of a compressed air generating device with an intercooler and an aftercooler, which are integrated in a silencer, and in which a coolant line is guided through a silencer sump, Fig. 2 is a compressed air generating device similar to that according to Fig. 1, in which a compressed air line which connects a second air compressor with an aftercooler, is guided through a silencer sump,

3 shows a compressed air generating device similar to that according to FIG. 1, but with a separate compressed air cooling module, in which ambient air can be sucked in through the silencer by a first air compressor,

4 shows a compressed air generating device similar to that according to FIG. 3, but with a different arrangement of a coolant temperature sensor, and with a water and particle filter arranged in the silencer, through which sucked-in ambient air can be conducted to the first air compressor,

5 shows a compressed air generating device similar to that according to FIGS. 1 to 4, in which a multi-circuit protection valve can be operated arranged outside a dryer module,

Fig. 6 shows a compressed air generating device similar to that according to Fig. 5, in which a multi-circuit protection valve is arranged outside the compressed air generating device and is connected to an electrical control and regulating device and the dryer module via flexible electrical and pneumatic lines, as well

Fig. 7 shows a compressed air generating device similar to that according to Fig. 4, but in which the ambient air for the first air compressor can be sucked in through an air inlet in the compressor module. In this drawing, pneumatic lines that carry air or compressed air are shown with a solid line. Hydraulic lines that transport liquid coolant are shown with a dashed line, and electrical lines are shown with a dotted line.

The basic structure of a compressed air generating device having the features of the invention is explained below with reference to FIG. 7.

In this exemplary embodiment, the compressed air generating device 2.7 shown in FIG. 7 has a closed but also openable housing 6, in which the components of the compressed air generating device 2.7 are combined into modules which are arranged one behind the other. The compressor 4, comprising an electric motor 24 including two drive shafts 30, 32, an inverter 26, a first air compressor 16, a second air compressor 18 and a control and regulating device 28, is arranged in a compressor module 90.

A compressed air cooling module 92 is then arranged in the housing 6 and has an intercooler 20 and an aftercooler 22. These two air coolers 20, 22 serve to cool the compressed air generated by the compressor 4. For this purpose, the two air coolers 20, 22 use a liquid coolant which is supplied by an external cooling device 82. In the example chosen here, this external cooling device 82 is a cooling device of a commercial vehicle with a suitable heat exchanger, not shown here. The aftercooler 22 is arranged so that it is the first component to be supplied with cold liquid coolant by the external cooling device 82. In addition, this aftercooler 22 is the last air cooler which is arranged in front of an air dryer 40 in the compressed air stream coming from the second air compressor 18.

To measure the coolant temperature, at least one temperature sensor is arranged, which is connected to the control and regulating device 28 via a data or sensor line 59. The temperature sensor 73 can be arranged at the coolant outlet of the external cooling device 82. Alternatively, the temperature sensor 73 'can be arranged at the coolant inlet of the aftercooler 22, or the temperature sensor sor 73" is arranged at the coolant outlet of the aftercooler 22. The most cost-effective arrangement of such a temperature sensor 73 is probably the arrangement at the coolant outlet of the external cooling device 82.

If a temperature sensor 73', 73" is arranged at the coolant inlet and at the coolant outlet of the aftercooler 22, the temperature reduction of the coolant as it flows through the aftercooler 22 can be determined by forming the difference between the measured values supplied by the two temperature sensors 73', 73" and thus the cooling effect the compressed air to be cooled can be determined. The reduction in the compressed air temperature that occurs due to the described energy transfer to the coolant at the aftercooler 22 can be determined, for example, if the temperature of the compressed air at the compressed air inlet of the aftercooler 22 and the per second compressed air volume flow through the aftercooler 22 are also known. Based on the reduction in the compressed air temperature that can be determined in this way, it can be determined which dew point shift in the compressed air has occurred and how much water is separated from the compressed air at the aftercooler 22 every second.

A dryer module 94 is subsequently placed in the housing 6, in which the aforementioned air dryer 40 and a multi-circuit protection valve 50 are arranged. The air dryer 40 contains a desiccant 41 with which atmospheric moisture can be removed from the compressed air supplied to the air dryer 40. The drying agent 41 can release this moisture back into dry air, namely when dry compressed air is passed through the air dryer 40 in the opposite direction during a regeneration process.

As will be explained further, the multi-circuit protection valve 50 does not have to be part of the dryer module 94, but its arrangement in the common housing 6 is advantageous. By means of the multi-circuit protection valve 50, it is possible to selectively deliver compressed air delivered by the air dryer 40 to different compressed air consumers 50, 51 via compressed air lines DL6, DL7 and/or to at least one compressed air reservoir 45 via a compressed air line DL8. In addition, it should be mentioned that the sixth compressed air line DL6 leading to the compressed air consumers 50, 51 and seventh compressed air line DL7 can also be connected to other compressed air storage units on the way there. Likewise, at least one further compressed air consumer, not shown, can be connected to the compressed air storage 45 shown. A 3/2 solenoid switching valve 72 arranged in the dryer module 94 enables the air dryer 40 to be switched into a drying mode or into a regeneration mode, the desiccant 41 of the air dryer 40 being able to be dried in the latter. This will be discussed further below. The 3/2 solenoid switching valve 72 is also referred to below as the regeneration switching valve.

Finally, the compressed air generating device 2.7 has a silencer module 96, which is designed here as a silencer 43, which contains a sound-absorbing material 44, which is only partially shown in the figures to make other details easier to see. This sound-absorbing material 44 is able to dampen sound emissions that arise during a regeneration process when moisture-laden regeneration exhaust air AL is released from the air dryer 40. The silencer module 96 has a plurality of regeneration air outlet openings, of which only one regeneration air outlet opening 34 is shown, through which regeneration exhaust air AL can be released into the environment. In addition, the silencer module 96 or the silencer 43 has at least one water outlet opening 36 at its deepest point, through which water droplets separated from the compressed air in the air dryer 40 during normal operation and/or splash water that has penetrated through the regeneration air outlet opening 34 is removed via a water separation path 80 that forms can be. The silencer module 96, the silencer 43 or the sound-absorbing material 44 can be attached to the housing 6 in an easily replaceable manner.

The components of the four modules 90, 92, 94, 96 described are connected to one another via pneumatic, hydraulic and electrical lines as far as necessary, which will be discussed separately in the description of the method for operating the compressed air generating device 2.7. The functionality and interaction of the components of the compressed air generating device 2.7 are as follows:

The operation of the compressor 4 is controlled and regulated by means of the control and regulating device 28 already mentioned. The control and regulating device 28 is connected via a low-voltage line 57 to a low-voltage source (not shown), to the mentioned data or sensor line 59 of a vehicle-specific data communication system, such as a CAN bus, and via at least one control line 54 to an inverter 26. The inverter 26, which influences the operation of the electric motor 24, is electrically connected via a high-voltage line 58 to a high-voltage source, not shown separately.

To start and operate the electric motor 24 of the compressor 4, it is controlled in the desired manner by means of the control and regulating device 28 and the inverter 26. This causes the two drive shafts 30, 32 of the electric motor 24 to rotate. The first drive shaft 30 is connected to the first air compressor 16 and the second drive shaft 32 to the second air compressor 18 in a driving manner. The two air compressors 16, 18 are known spiral compressors. The first air compressor 16 is connected to the ambient air L on the input side via an air inlet opening 8 in the housing 6. When the first air compressor 16 is operating, it sucks in ambient air L via a suction line DL and compresses it into compressed air with a first air pressure value.

The first air compressor 16 is pneumatically connected on the output side via a first compressed air line DL1, the intercooler 20 and then via a second compressed air line DL2 to the inlet of the second air compressor 18. The intercooler 20 cools the precompressed compressed air, whereby water is condensed out and removed if necessary. In the second air compressor 18, the cooled compressed air is then further compressed to a desired second, higher air pressure value and then fed to the already mentioned aftercooler 22 via a third compressed air line DL3. The compressed air is further cooled in the aftercooler 22. Humidity from the compressed air condenses. From the outlet of the aftercooler 22, the cooled and still residually moist compressed air reaches an inlet-side collecting area 49 of the air dryer 40 via a fourth compressed air line DL4. The already condensed water also reaches this collecting area 49 of the air dryer 40 in the form of entrained small droplets or as a film of water. From there, the water is separated from the air dryer 40 via a regeneration air outlet 42 during a later regeneration process. As a result, the condensed water did not get into the drying agent 41 of the air dryer 40, as shown schematically in FIG. 7 with small droplets. The compressed air, which has been partially dewatered in this way and is still still moist, arrives from the short fourth compressed air line DL4 into the drying agent 41 of the air dryer 40, flows through this drying agent 41 in a drying air stream 23 and is dried there. The desiccant 41 is able to remove atmospheric moisture from the supplied compressed air and release it back into dry air during a later regeneration process.

The dried compressed air then leaves the air dryer 40 via a spring-loaded first check valve 29 which shuts off in the direction of the air dryer 40, and then enters a fifth compressed air line DL5. This fifth compressed air line DL5 leads to the already mentioned multi-circuit protection valve 50, which is controlled at least indirectly by the control and regulating device 28. For this purpose, the multi-circuit protection valve 50 is connected to the control and regulating device 28 via a sensor line 56. Via the multi-circuit protection valve 50, the dried compressed air can be directed, for example, through the already mentioned sixth compressed air line DL6 and a compressed air outlet opening 10 in the housing 6 to the first compressed air consumer 51 and via the mentioned seventh compressed air line DL7 to the second compressed air consumer 52. The multi-circuit protection valve 50 can direct dried compressed air to the at least one compressed air reservoir 45 via the eighth compressed air line DL8. Other compressed air consumers and/or compressed air reservoirs (not shown) can also be supplied with compressed air if necessary via the compressed air storage 45. If necessary, the compressed air stored in the compressed air storage 45 can also be supplied to other compressed air consumers via the multi-circuit protection valve 50 or for one Regeneration of the desiccant 41 of the air dryer 40 is returned to the fifth compressed air line DL5.

If a predetermined air pressure is set in the compressed air consumers 51, 52 and in the at least one compressed air storage 45 and the electric motor 24 of the compressor module 90 is switched off, the drying agent 41 arranged in the air dryer 40 and saturated with moisture can be regenerated, i.e. from that stored there water to be freed. For this purpose, the compressed air generating device 2.7 has a regeneration line DL5a. This regeneration line DL5a is indirectly connected via the fifth compressed air line DL5 at least to the eighth compressed air line DL8 leading to the compressed air storage 45 and to the air dryer 40. The 3/2-way solenoid switching valve 72 already mentioned above is arranged in the regeneration line DL5a, which is connected to the control and regulating device 28 via a control line 55 and can be controlled by it.

When the 3/2-way solenoid switching valve 72 is not actuated, the regeneration line DL5a is closed as shown in FIG. 7, so that no compressed air can reach the air dryer 40 from the compressed air reservoir 45 via the multi-circuit protection valve 50. To carry out a regeneration operation of the air dryer 40, the 3/2-way solenoid switching valve 72 is actuated, as a result of which the regeneration line DL5a is opened. As a result, part of the dried compressed air from the compressed air reservoir 45 passes through a first line branch DL5b of the regeneration line DL5a to an aperture 75. There the dried compressed air is expanded, whereby it takes up a larger volume. The compressed air then passes through a second spring-loaded check valve 76 that opens in the direction of the air dryer 40 and then reaches the air dryer 40 via a regeneration compressed air inlet 70. The relaxed compressed air then flows through the air dryer 40 and the drying agent 41 arranged there in a regeneration compressed air stream 77, provided that a pressure-controlled, 2/2-way switching valve 39, which acts as a drain valve, is open at the collecting area 49 of the air dryer 40. To operate this pressure-controlled 2/2-way switching valve 39, another part of the dried compressed air is passed behind the outlet of the 3/2-way solenoid switching valve 72 through a second line branch DL5c to this pressure-controlled 2/2-way switching valve 39. The pressure-controlled 2/2-way switching valve 39 is constructed in such a way that in its unactuated switching position it closes a connection from the collecting area 49 of the air dryer 40 to the regeneration air outlet 42 of the air dryer 40 and opens it in the actuated switching state. Accordingly, the pressure-controlled 2/2-way switching valve 39 is opened when the 3/2-way solenoid switching valve 72 has also been switched to its open position.

According to an alternative embodiment, it is provided that instead of the 3/2-way solenoid switching valve 72, there are two 2/2-way solenoid switching valves that can be controlled by the control and regulating device 28. These two 2/2-way solenoid switching valves are not shown in the figures, but their arrangement can be easily understood by a person skilled in the art based on the following description. The first 2/2-way solenoid switching valve is arranged in the flow direction of the regeneration compressed air in front of the orifice 75 in the first line branch DL5b, and the second 2/2-way solenoid switching valve is in front of the pressure-controlled 2/2-way switching valve 39 in the second Line branch DL5c arranged. In addition, the fifth compressed air line DL5 is connected directly to the first line branch DL5b and directly to the second line branch DL5c in the flow direction of the regeneration compressed air in front of the two 2/2-way solenoid switching valves. As soon as these two 2/2-way solenoid switching valves are switched to their open position, dry regeneration compressed air can be passed through the air dryer 40 into the silencer 43 with the pressure-controlled 2/2-way switching valve 39 also open in order to dry the desiccant 41.

By means of this structure, when the first 2/2-way solenoid switching valve is closed, the second 2/2-way solenoid switching valve is open and the pressure-controlled 2/2-way switching valve 39 is therefore open, the collecting area 49 of the air dryer 40 can pass through the aftercooler 22 supplied compressed air can advantageously be freed from water W that has accumulated there. But now back to the exemplary embodiment shown in FIG. 7: When the pressure-controlled 2/2-way switching valve 39 is open, the relaxed compressed air flows through the desiccant 41 in the mentioned regeneration compressed air stream 77 in the direction of the silencer 43. Moisture is removed from the desiccant 41 . The compressed air enriched with moisture in this way and the water that has already condensed and accumulated in the collecting area 49 of the air dryer 40 then leave the air dryer 40 via its regeneration air outlet 42 and thus reach the silencer 43.

The moist regeneration exhaust air AL then flows through the sound-absorbing material 44 arranged in the silencer 43 via an exhaust air path 78 to the at least one regeneration air outlet opening 34 of the silencer 43 of the compressed air generating device 2.7. Water droplets, which may have formed in the regeneration compressed air stream or which form in the sound-absorbing material 44 of the silencer 43 when the regeneration compressed air stream flows through there, as well as the condensed water from the collecting area 49 of the air dryer 40, flow in the silencer 43 via the already mentioned water separation path 80 towards the at least one water outlet opening 36 of the silencer 43. The water outlet opening 36 of the silencer 43 also serves to remove any splash water that may have penetrated into the silencer 43 via the at least one regeneration air outlet opening 34.

The regeneration process is ended when a predetermined, sufficiently large volume of regeneration compressed air has flowed through the drying agent 41 of the air dryer 40 in order to be able to use it for a further air drying phase.

Of great importance for the inventive structure of the compressed air generating device 2.7 is the flow path of the liquid coolant supplied by the external cooling device 82. This coolant is cooled to a predetermined temperature in the external cooling device 82 and supplied to the compressed air generating device 2.7 via a coolant supply line Kin. The cooling activity of the external cooling device 82 is controlled and regulated with the control and regulating device 28. With a preferred control of the temperature of the Coolant, the current actual temperature of the coolant is measured with a first temperature sensor 73 at the output of the cooling device 82, and then the coolant temperature is regulated to a predetermined setpoint of the coolant temperature. For this purpose, the first temperature sensor 73 is connected to the control and regulating device 28 via the data and/or sensor line 59.

The coolant passes from the external cooling device 82 through a coolant inlet opening 12 into the compressed air generating device 2.7 and into the compressed air cooling module 92. The coolant then flows through a first coolant line KL1 into the aftercooler 22 in order to cool the compressed air generated by the compressor 4 as much as possible . Since the coolant is first passed into the aftercooler 22, the lowest temperature of the coolant that it has within the compressed air generating device 2.7 can be used. As a result, the compressed air is cooled comparatively strongly before it enters the air dryer 40, as a result of which some of the air moisture carried condenses out and is at least partially separated in the aftercooler 22. The condensed water is also passed into the collecting area 49 of the air dryer 40 and from there discharged into the environment directly or via the silencer 43. This process removes a lot of moisture from the compressed air before it reaches the air dryer 40. This is all the more the lower the temperature of the coolant.

As a result, the desiccant 41 of the air dryer 40 needs to be dried less frequently in regeneration operations compared to conventional compressed air generating devices, or such regeneration operations may be performed with a smaller volume of regeneration compressed air than usual. As a result, more of the dry compressed air stored in the compressed air storage 45 is available for the compressed air consumers 51, 52, so that the electric motor 24 of the compressor 4 of the compressed air generating device 2.7 has to be in operation less frequently. As a result, for example when arranging and operating such a compressed air generating device 2.7 in a vehicle, the consumption of electrical energy is reduced, which reduces the vehicle's exhaust emissions and thus its CC emissions. The frequency of the regeneration processes or the respectively required regeneration compressed air volume can therefore be smaller, the lower the temperature of the coolant at the inlet of the aftercooler 22. It is therefore advantageous if the regulation of the frequency of actuation and/or the regulation of the duration of actuation of the regeneration switching valve designed as a 3/2-way solenoid switching valve 72 is also carried out by means of the control and regulating device 28 as a function of the temperature of the coolant. For this purpose, as already briefly mentioned, according to the exemplary embodiment shown in FIG. 7, a first temperature sensor 73 is arranged in the area of the outlet of the external cooling device 82 or in the area of the coolant inlet opening 12, by means of which the temperature of the liquid coolant can be measured. Typically, such a temperature sensor 73 is already a component of the external cooling device 82, so its use does not cause any additional manufacturing costs. The temperature measurements obtained in this way can be routed to the control and regulating device 28 via the data and/or sensor line 59 mentioned. The control and regulating device 28 then controls and regulates the regeneration of the desiccant 41 of the air dryer 40, taking into account the current coolant temperature, directly via the frequency of actuation and/or the duration of actuation of the 3/2-way solenoid switching valve 72 and indirectly by means of the pressure-controlled 2/2 -way switching valve 39.

7 also shows alternative solutions, according to which the temperature of the coolant at the coolant inlet of the aftercooler 22 can be measured by means of a second temperature sensor 73' and/or at the coolant outlet of the aftercooler 22 by means of a third temperature sensor 73''. These temperature sensors 73′, 73″ are then also connected to the control and regulating device 28 via the data and/or sensor line 59. The data and/or sensor line 59, which is connected to the respective temperature sensor 73, 73', 73", can also, unlike shown in FIG. 7, be arranged completely within the compressed air generating device 2.7.

With such a control, it should also be noted that the temperature of the coolant can fluctuate during operation of the compressed air generating device 2.7. This can be caused by different load conditions of the vehicle and its systems and/or by itself rapidly changing ambient temperatures. Since the current temperature of the coolant is measured with the first temperature sensor 73 in most vehicles in order to regulate the external cooling device 82 mentioned, its current value is available to the control and regulating device 28 via the already mentioned data and/or sensor line 59 CAN bus available. Based on the current value of the temperature of the coolant, the control and regulating device 28 can therefore quickly control and regulate the duration of operation of the 3/2-way solenoid switching valve 72 and thus the frequency and duration of a regeneration process on the dryer 40 depending on the temperature at any time.

Since in most vehicles on the road today, the ambient temperature of the vehicle is also measured by means of an ambient temperature sensor 74 and displayed with a display element, the ambient temperature also represents the control and regulation of the operating time of the 3/2-way solenoid switching valve 72 and thus for the Control and regulation of the frequency and duration of a regeneration process on the air dryer 40 is available to the control and regulating device 28 via the data and/or sensor line 59 of the CAN bus.

The ambient temperature of the vehicle is of particular importance for the control and regulation of the regeneration processes because the compressed air, after it has been dried in the dryer 40, continues to cool down to the temperature of the compressed air tank 45 or the compressed air consumers 51, 52, which generally have the ambient temperature . During this further cooling process, the relative humidity in the compressed air increases again. To ensure that excessive air humidity does not lead to corrosion processes in the compressed air storage tanks and compressed air consumers when ambient temperatures are low in relation to the coolant temperature, or even water condenses out and freezes into ice, the degree of drying of the compressed air must ideally also take the current ambient temperature into account.

This degree of drying can be adjusted via the regeneration compressed air volume used in a regeneration process and/or via the frequency of the regeneration processes in a period under consideration. If, for example, a volume of regeneration compressed air that is actually too large is used during a regeneration process, the drying agent 41 becomes drier than this is required according to previously known practice. During a subsequent conveying process, the compressed air passed through the air dryer 40 will lose more moisture than previously necessary, as a result of which the compressed air has a higher degree of drying when it leaves the air dryer 40. When the compressed air then cools down further in a compressed air container or in a compressed air consumer, the degree of drying of the compressed air is then advantageously uncritically high, so that condensation and possibly ice formation do not occur when the compressed air is cooled further.

The regeneration compressed air volume and/or the frequency of the regeneration processes is therefore controlled and regulated by means of the control and regulating device 28 at a constant ambient temperature depending on the temperature of the coolant, and at a constant temperature of the coolant it is controlled and regulated depending on the ambient temperature.

If both the ambient temperature and the coolant temperature change, the duration and/or frequency of the regeneration processes is controlled and regulated depending on the difference between the two temperatures mentioned.

If such a regulation is omitted, the volume of regeneration compressed air required for a regeneration process must also cover the most unfavorable case, i.e. take into account the highest temperature of the coolant to be expected during operation of the compressed air generating device 2.7. As a result, such a regeneration process for the drying agent 41 would always take place with a previously determined maximum regeneration compressed air volume.

After the liquid coolant has flowed through the aftercooler 22, it reaches the intercooler 20 mentioned via a second coolant line KL2. There it cools the compressed air precompressed by the first air compressor 16. After cooling the pre-compressed compressed air in the intercooler 20, the liquid coolant is conducted via a third coolant line KL3 to a cooling device 25 of the electric motor 24. There the coolant cools, for example, the stator of the electric motor 24. The coolant then flows through a fourth coolant line KL4 to a cooling device 48 of the second air compressor 18 of the compressor 4, which is thereby cooled during its compression activity. The coolant then flows through a fifth coolant line KL5 to a cooling device 27 of the inverter 26 in order to cool this too. Subsequently, the coolant is passed through a sixth coolant line KL6 to a cooling device 46 of the first air compressor 16 of the compressor 4 in order to cool it. Finally, the heated coolant is passed through a coolant outlet opening 14 from the compressor module 90 and from the housing 6 of the compressed air generating device 2.7 via a coolant discharge line Kout to the external cooling device 82.

Investigations have shown that the described, comparatively strong cooling of the compressed air in the aftercooler 22 has no negative effects on the operation of the compressed air generating device 2.7. There are even other benefits that can be seen. This will be explained using the following example:

In this case, a compressed air generating device 2.7 designed according to the invention is installed in a truck and for cooling it uses the liquid coolant of the cooling system, which also cools the internal combustion engine of the truck and serves as a heat source for interior heating. When starting the internal combustion engine cold, i.e. starting it at a very low ambient temperature, it is advantageous in terms of the operating properties of a vehicle battery, in terms of low exhaust emissions from the truck and in terms of the provision of warm air for an interior heater in the truck if the temperature of the cooling system of the internal combustion engine quickly rises above Ambient temperature is increased. Because the electrically operated compressed air generating device 2.7 is immediately put into operation when the internal combustion engine is cold started to generate compressed air that is necessary for operation, it is cooled as far as possible by the liquid coolant. The waste heat thereby removed from the compressed air generating device 2.7, in particular the heat which is generated by the operation of the electric motor 24, the inverter 26 and the two air compressors 16, 18, then advantageously also serves indirectly for a Relieving the load on the vehicle battery. For the period of the cold start and a short warm-up phase of the truck, temperatures at which water ice can form can also be accepted at the aftercooler 22 and at the inlet of the air dryer 40. Since the warm-up phase is comparatively short, in the normal operating phase that follows, any water ice formed on the aftercooler 22 and at the inlet of the air dryer 40 will evaporate and be absorbed into the compressed air as atmospheric moisture.

The compressed air generating devices 2.1, 2.2, 2.3, 2.4, 2.5, 2.6 shown in FIGS. 1 to 6 also have very largely the design features explained in connection with FIG. 7 and work according to the method described. According to the invention, in all compressed air generating devices 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7 shown in Figures 1 to 7, it is provided that the control and regulating device 28 is designed and arranged in such a way that the operation of the electric motor 24, a drying operation and a regeneration operation of the air dryer 40, as well as the operation of a multi-circuit protection valve 50 can be controlled and regulated, and that the air cooler 22, which is arranged as the last air cooler in front of the air dryer 40 in the flow direction of the compressed air, is the first of the air cooler 22 in the flow direction of the coolant Coolant can flow through. However, the compressed air generating devices 2.1, 2.2, 2.3, 2.4, 2.5, 2.6 shown in Figures 1 to 6 have further advantageous special features, which are described below.

1 shows, the compressed air generating device 2.1 there does not have a separate compressed air cooling module 92, because the two air coolers, i.e. the intercooler 20 and the aftercooler 22, are arranged in the installation space of the silencer module 96 * or in the installation space of the silencer 43 itself . In order to supply these air coolers 20, 22 with the liquid coolant, the air coolers 20, 22 are connected to coolant lines KL1, KL2, KL2, which are also at least partially arranged in the installation space of the silencer module 96* or in the installation space of the silencer 43 . The same applies to the first compressed air line DL1 and the second compressed air line DL2, which are pneumatically connected to the intercooler 20, and the third compressed air line DL3 and the fourth compressed air line DL4, which are pneumatically connected to the aftercooler 22. To ensure the supply of the To enable liquid coolant from the external cooling device 82 via a coolant supply line Kin to the aftercooler 22, the silencer module 96* or the silencer 43 has a coolant inlet opening 12*, to which the coolant supply line Kin and the internal, first coolant line KL1 are connected .

By arranging the two air coolers 20, 22, the associated compressed air lines DL1, DL2, DL3, DL4 and the coolant lines KL1, KL2 mentioned in the installation space of the silencer module 96 * or in the installation space of the silencer 43, the compressed air generating device 2.1 in comparison The compressed air generating device 2.7 described above according to FIG. 7 has a shorter length, so that this compressed air generating device 2.1 requires little space in a motor vehicle.

In addition, in the compressed air generating device 2.1 according to FIG. 1 it is provided that the silencer module 96 * or the silencer 43, unlike the compressed air generating device 2.7 according to FIG. In order to be able to remove water W that accumulates in a sump area 98 of the silencer 43 or the silencer module 96*, the first coolant line KL1 is arranged in the sump area 98 of the silencer 43. This makes it possible for the water W accumulated there, be it condensation or splash water that has penetrated into the silencer 43, to evaporate into water vapor 86 at least when the temperature of the water W is lower than the temperature of the coolant supplied by the external cooling device 82 . The comparatively high temperature of the coolant required for this can be set for a short period of time using the control and regulating device on the external cooling device 82. Which temperature of the coolant is necessary for this is calculated using the ambient temperature measured by a fourth temperature sensor 74. The ambient temperature can be used as control information, since it can be assumed that the sump area 98 of the silencer 43 and the water W located therein have the ambient temperature. The water vapor 86 that forms passes inside the silencer 43 or the Silencer module 96* via the exhaust air path 78 in the silencer 43 to the regeneration air outlet opening 34 and from there into the ambient air.

It is also of great advantage in this compressed air generating device 2.1 according to FIG. 1 that due to the arrangement of the two air coolers 20, 22 and the compressed air lines DL1, DL2, DL3, DL4, heat from the hot compressed air into the silencer 43 or into the silencer module 96* is entered. This heat means that during a regeneration process and/or through the regeneration air outlet opening 34 into the silencer 43, atmospheric moisture or water W will hardly accumulate in the sump area 98 of the silencer 43, because this is constantly evaporated during the operation of the compressed air generating device 2.1 and as water vapor 86 is removed from the compressed air generating device 2.1 via the regeneration air outlet opening 34 at the latest during the next regeneration operation.

At this point it should be noted that the silencer 43 or the silencer module 96* is connected or can be connected to the housing 6 of the compressed air generating device 2.1 and the lines there, but is not structurally integrated into this housing 6.

This is different with the compressed air generating device 2.2 according to FIG. 2, in which the silencer 43 or the silencer module 96 * is integrated in the housing 6. However, this is not the only difference to the compressed air generating device 2.1 according to FIG the coolant inlet of the aftercooler 22. In addition, in this compressed air generating device 2.2 according to FIG. 2, the third compressed air line DL3 coming from the second air compressor 18 is not led directly to the compressed air inlet of the aftercooler 22. Rather, this third compressed air line DL3 is first led to the sump area 98 of the silencer 43 and has a heating coil-shaped section 84 there. Only behind this heating coil-shaped one In section 84, the third compressed air line DL3 is connected to the compressed air inlet of the aftercooler 22.

In the exemplary embodiment shown, the heating coil-shaped section 84 of the third compressed air line DL3 is partially surrounded by water W, which has accumulated there due to the supply of condensation or the penetration of splash water. As a result, the heating coil-shaped section 84 of the third compressed air line DL3 heats the water W during operation of the compressed air generating device 2.2 and water vapor 86 is formed, which is released at the latest during the next regeneration operation via the exhaust air path 78 in the silencer 43 to the regeneration air outlet opening 34 and from there into the ambient air.

The third embodiment shown in FIG. 3 of a compressed air generating device 2.3 having the features of the invention, like the first embodiment of the compressed air generating device 2.1 according to FIG 94 is arranged. In contrast to the compressed air generating device 2.1 according to FIG. 1, the compressed air generating device 2.3 according to FIG. To save manufacturing costs, this air inlet 8* is identical to the at least one regeneration air outlet opening 34, which is only required by the compressed air generating device 2.3 when it is operated in regeneration mode. For the rest of the time, i.e. for most of the time, this at least one regeneration air outlet opening 34 serves as an air inlet 8 * through which ambient air L can be sucked in to the first air compressor 18.

The ambient air L passes from this alternately usable opening 8 *, 34 via the sound-absorbing material 44 arranged in the silencer 43 and the intake line DL to the inlet of the first air compressor 16 in order to be compressed into compressed air in a first compression process. Afterward the compressed air follows the description of the compressed air generating device 2.1

Fig. 7 already explained flow path.

The fourth variant of the compressed air generating device 2.4 shown in FIG. 4 is designed largely identically to the compressed air generating device 2.3 according to FIG and dirt particles could be contaminated, a water and particle separator 88 is arranged in or on the silencer 43. The water W filtered out of the sucked-in ambient air L by this water and particle separator 88 is passed along with filtered-out dirt particles to the water outlet opening 36 of the silencer 43, where it is discharged into the environment.

5 shows a fifth variant of a compressed air generating device 2.5 having the features of the invention. This differs from the compressed air generating device 2.3 shown in FIG. 3 only in that the multi-circuit protection valve 50 does not belong to the dryer module 94. 5 illustrates, the multi-circuit protection valve 50 can be arranged and operated remotely from the dryer module 94 on or remotely from the compressed air generating device 2.5. For this purpose, the multi-circuit protection valve 50 has pneumatic connecting means 62 on the input side, via which the multi-circuit protection valve 50 is releasably connected to the fifth compressed air line DL5 of the dryer module 94 described above. In addition, the multi-circuit protection valve 50 has output-side pneumatic connecting means 66, via which the multi-circuit protection valve 50 is releasably connected to the sixth, seventh and eighth compressed air lines DL6, DL7, DL8. As already described, these compressed air lines DL6, DL7, DL8 lead to compressed air consumers 51, 52 and to at least one compressed air reservoir 45. In addition, the multi-circuit protection valve 50 has electrical connection means 64, by means of which the multi-circuit protection valve 50 can be detached from electrical connection means 68 of the control and regulating device 28 connected is. The hydraulic connecting means 62, 66 are preferably designed as compressed air connection sockets into which compressed air plugs can be detachably inserted. These compressed air connectors are arranged on the compressed air lines DL5, DL6, DL7, DL8. The compressed air lines DL5, DL6, DL7, DL8 can be designed as flexible compressed air lines.

The electrical connection means 64 on the multi-circuit protection valve 50 is preferably designed as an electrical socket. An electrical plug of a sensor line 56 can be detachably inserted into this, which has, for example, a second electrical plug at its other end, which can also be detachably inserted into an associated electrical connecting means 68 designed as a plug socket on the control and regulating device 28.

Due to the described structure of the compressed air generating device 2.5, the multi-circuit protection valve 50 can also be arranged remotely from the compressed air generating device 2.5, so that it does not have to be removed from the compressed air system of a vehicle for repair purposes if the compressed air generating device 2.5 is damaged.

It should be mentioned at this point that the control and regulating device 28 is designed in such a way and is connected to the other components of the compressed air generating device 2.5 via sensor lines and control lines that the control and regulating device 28 controls the operation of the inverter 26 and thus the operation of the electric motor 24 as well can control and regulate, such as the dryer operation and the regeneration operation of the air dryer 40. In addition, the control and regulating device 28 at least indirectly controls and regulates the operation of the multi-circuit protection valve 50.

The control and regulating device 28 can be structurally integrated, for example, in the inverter 26 or in the multi-circuit protection valve 50. This prevents the control and regulating device 28 from remaining on the vehicle in the repair case described.

Finally, a sixth embodiment of a compressed air generating device 2.6 having the features of the invention is shown in FIG. As with the in The fourth embodiment shown in FIG. 4 is also provided here that the multi-circuit protection valve 50 can be separated from the other components of the compressed air generating device 2.6 and can be operated remotely from these components. For this purpose, the control and regulating device 28 and the multi-circuit protection valve 50 have electrical connection means 64; 68, which are at least indirectly releasably connected to one another via the at least one flexible electrical line 56. In addition, the multi-circuit protection valve 50 has pneumatic connecting means 62, which are at least indirectly releasably connected to the outlet of the air dryer 40 via at least one flexible pneumatic line 106.

In addition, the compressed air generating device 2.6 has an electric motor 24 and two air compressors 16, 18 which can be driven by the electric motor 24 and act one after the other. The compressed air generating device 2.6 also has an air inlet 8*, via which ambient air L can be sucked in by means of the first air compressor 16. There is also an intercooler 20 and an aftercooler 22, the inlet of the intercooler 20 being pneumatically connected to the outlet of the first air compressor 16, the outlet of the intercooler 20 being pneumatically connected to the inlet of the second air compressor 18, and the outlet of the second air compressor 18 is pneumatically connected to the inlet of the aftercooler 22. There is also an air dryer 40, the input of which is pneumatically connected to the output of the aftercooler 22. To supply a coolant, there is a coolant inlet opening 12, via which a liquid coolant can be supplied to the intercooler 20 and the aftercooler 22 from a first external cooling device 82. Heated coolant can be discharged to the external cooling device 82 via a coolant outlet opening 14.

The compressed air generating device 2.6 according to FIG. 6 feeds a multi-circuit protection valve 50 with compressed air, via which the output of the air dryer 40 is pneumatically connected to at least one external compressed air storage 45 and external compressed air consumers 51, 52. There is also a control and regulating device 28, which is connected to the multi-circuit protection valve 50 and the sensors arranged there via at least one sensor line 56. In this compressed air generating device 2.6 according to FIG. 6 it is provided that a dryer module 94* having the air dryer 40 has at least one electrical socket 100 and at least one pneumatic socket 104. The electrical socket 100 of the dryer module 94* is connected to an electrical socket 68 on the control and regulating device 28 via the sensor line 56 mentioned. An electrical plug of an electrical connecting line 102 is detachably plugged into the electrical socket 100 of the dryer module 94. This electrical connecting line 102 has a second plug which is detachably plugged into an electrical plug socket 64 of the multi-circuit protection valve 50. The pneumatic socket 104 of the dryer module 94* is pneumatically connected to the fifth compressed air line DL5, through which dry compressed air coming from the air dryer 40 can be conducted to the compressed air consumers 51, 52 and to the compressed air storage 45. A plug of a pneumatic connecting line 106 is detachably inserted into this pneumatic socket 104 of the dryer module 94*. The pneumatic connecting line 106 has a second plug which can be detachably inserted into a pneumatic socket 62 of the multi-circuit protection valve 50.

In this compressed air generating device 2.6, the multi-circuit protection valve 50 can be arranged comparatively far from the other components of the compressed air generating device 2.6. The realizable distance is determined in particular by the maximum sensible length of the electrical connecting line 102 and the pneumatic connecting line 106. The use of such a compressed air generating device 2.6 takes place, for example, in a vehicle train consisting of a towing vehicle and several trailer vehicles, in which the multi-circuit protection valve 50 is arranged on one of the trailer vehicles, but the core components of the compressed air generating device 2.6 are placed on the towing vehicle.

In this way, it can be achieved in particular that the compressed air lines DL6, DL7, DL8 emanating from the multi-circuit protection valve 50 and leading to the compressed air consumers 51, 52 and the at least one compressed air reservoir 45 can be kept comparatively short. This reduces manufacturing costs and reduces the risk of cable damage due to the reduced overall cable length be reduced. In addition, the air dryer module 94* can be made narrower, which can be advantageous when space on a vehicle is limited.

6, according to an alternative embodiment, the multi-circuit protection valve 50 with all of its sensors and electromagnetic switching valves arranged there can be connected to a central control device 110 of the vehicle via a single electrical line 108. In this variant, the central control device 110 would then also be electrically connected to the 3/2-way solenoid switching valve 72 or to the two 2/2-way solenoid switching valves used for this purpose via at least one control line 112. Such a central control device 110 of the vehicle would then also take over all other tasks of the control and regulating device 28 described.

List of reference symbols (part of the description)

2.1 Compressed air generating device (first embodiment)

2.2 Compressed air generating device (second embodiment)

2.3 Compressed air generating device (third embodiment)

2.4 Compressed air generating device (fourth embodiment)

2.5 Compressed air generating device (fifth embodiment)

2.6 Compressed air generating device (sixth embodiment)

2.7 Compressed air generating device (seventh embodiment)

4 compressor

6 Housing of the compressed air generating device

8 air inlet (first embodiment)

8* Air inlet (second embodiment)

10 Compressed air outlet opening

12 Coolant inlet opening (first embodiment)

12* Coolant inlet port (second embodiment)

14 Coolant outlet opening

16 First air compressor

18 Second air compressor

20 intercoolers, air coolers

22 aftercoolers, air coolers

23 drying air flow in the air dryer

24 electric motor

25 Electric motor cooling device

26 inverters

27 Inverter cooling device

28 control and regulating device

29 First check valve

30 First drive shaft

32 Second drive shaft

34 Regeneration air outlet opening

36 Silencer water outlet opening

39 Pressure-controlled 2/2-way switching valve, drain valve on the air dryer Air dryer

Desiccant in the air dryer

Regeneration air outlet of the air dryer

silencer

Sound absorbing material

Compressed air storage

Cooling device of the first air compressor

Cooling device of the second air compressor

Collection area of the air dryer for water

Multi-circuit protection valve

First compressed air consumer

Second compressed air consumer

Control line

Control line from the control and regulating device to the 3/2-way switching valve Sensor line from the control and regulating device to the multi-circuit protection valve Low-voltage line

High voltage line

Data line and/or sensor line, CAN bus

Inlet-side pneumatic connecting means on the multi-circuit protection valve Electrical connecting means on the multi-circuit protection valve

Output-side pneumatic connecting means on the multi-circuit protection valve Electrical connecting means on the control and regulating device Regeneration compressed air inlet of the air dryer 3/2-way solenoid switching valve

First temperature sensor (measuring coolant) ‘ Second temperature sensor (measuring coolant) ‘ Third temperature sensor (measuring coolant)

Fourth temperature sensor, (measuring ambient temperature)

cover

Second check valve

Regeneration compressed air flow in the air dryer

Exhaust air path in the silencer

Water separation path in the silencer External cooling device 84 Heating coil-shaped section of the third compressed air line DL3

86 water vapor

88 water and particle separators

90 compressor module

92 Compressed air cooling module

94 dryer module (first embodiment)

94* Dryer module (second embodiment)

96 Silencer module (first embodiment)

96* Silencer module (second embodiment)

98 Silencer sump area

100 Electrical socket on the dryer module

102 Electrical connection cable

104 Pneumatic socket on the dryer module

106 Pneumatic connecting line

108 Electrical line from the multi-circuit protection valve to the control unit 110

110 Central control unit of a vehicle

112 Control line from control unit 110 to 3/2-way solenoid switching valve

AL regeneration exhaust air

DL intake line for ambient air

DL1 First compressed air line

DL2 Second compressed air line

DL3 Third compressed air line

DL4 Fourth compressed air line

DL5 Fifth compressed air line

DL5a regeneration line

DL5b First line branch

DL5c Second line branch

DL6 Sixth compressed air line

DL7 Seventh compressed air line

DL8 Eighth compressed air line

KL1 First coolant line

KL2 Second coolant line

KL3 Third coolant line

KL4 Fourth coolant line KL5 Fifth coolant line

KL6 Sixth coolant line

Kin coolant supply line

Kout coolant drain line

L Ambient air

W water

Claims

Patent claims

1. Compressed air generating device (2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7), with a control and regulating device (28), with at least one controllable and regulatable electric motor (24), with at least one that can be driven by the electric motor (24). Air compressor (16; 18), with an air inlet (8, 8*), via which ambient air (L) can be sucked into the at least one air compressor (16, 18), with at least one air cooler (20, 22), which is connected to the outlet of the at least one air compressor (16, 18), with an air dryer (40), the inlet of which is connected to the outlet of the at least one air cooler (20; 22), with a coolant inlet opening (12, 12 *), via which the at least a liquid coolant can be supplied to an air cooler (20; 22) and other components of the compressed air generating device, and with a coolant outlet opening (14), via which heated coolant can be removed from the compressed air generating device, characterized in that the control and regulating device (28) is designed in this way and it is arranged that the operation of the electric motor (24), a drying operation and a regeneration operation of the air dryer (40), as well as the operation of a multi-circuit protection valve (50) can be controlled and regulated, and that the air cooler (22), which in the direction of flow the compressed air is arranged as the last air cooler in front of the air dryer (40), as seen in the flow direction of the coolant, the coolant can flow through it first.

2. Compressed air generating device (2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7), according to claim 1, characterized in that at least one temperature sensor (73, 73 ', 73") is present, which is used to measure the coolant temperature in front of the coolant inlet and/or is arranged behind the coolant outlet of the air cooler (22), which is placed as the last air cooler in front of the air dryer (40) in the direction of flow of the compressed air, and that this has at least one temperature sensor (73, 73 ', 73") with the control and control device (28) is connected via a data or sensor line (59).

3. Compressed air generating device (2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7) according to claim 1 or 2, with an electric motor (24), with two driven by the electric motor (24). and successively effective air compressors (16, 18), with an air inlet (8, 8*), through which ambient air (L) can be sucked in by means of the first air compressor (16), with a first air cooler designed and arranged as an intermediate cooler (20) and with a second air cooler designed and arranged as an aftercooler (22), the inlet of the intercooler (20) being pneumatically connected to the outlet of the first air compressor (16), the outlet of the intercooler (20) being connected to the inlet of the second air compressor (18) is pneumatically connected, and wherein the output of the second air compressor (18) is pneumatically connected to the input of the aftercooler (22), to an air dryer (40), the input of which is connected to the output of the aftercooler (22), and to a coolant inlet opening (12, 12*), via which a liquid coolant can be supplied to the intercooler (20) as well as the aftercooler (22) and other components of the compressed air generating device, and with a coolant outlet opening (14), via which heated coolant can be removed, characterized in that the aftercooler (22), which is arranged as the last air cooler in front of the air dryer (40) in the direction of flow of the compressed air, is the first through which the coolant can flow when viewed in the direction of flow of the coolant, that at least one temperature sensor (73, 73 ', 73") is present is, which is connected to the control and regulating device (28) via a data or sensor line (59), that the temperature sensor (73, 73 ', 73") for measuring the coolant temperature in front of the coolant inlet or behind the coolant outlet of the aftercooler ( 22) is arranged, and that the control and regulating device (28) is designed such that, in addition to the operation of the electric motor (24), a drying operation and a regeneration operation of the air dryer (40) as well as the operation of a multi-circuit protection valve (50) can be controlled and is adjustable.

4. Compressed air generating device (2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7) according to one of claims 2 or 3, characterized in that the temperature sensor (73) for measuring the coolant temperature in front of the coolant inlet opening (12, 12 *) of the compressed air generating device is arranged.

5. Compressed air generating device (2.4, 2.7) according to one of claims 2 or 3, characterized in that the temperature sensor (73 ') for measuring the Coolant temperature is arranged immediately in front of the coolant inlet of the aftercooler (22), which is arranged as the last air cooler in front of the air dryer (40) in the direction of flow of the compressed air.

6. Compressed air generating device (2.4, 2.7) according to one of claims 2 or 3, characterized in that the temperature sensor (73") for measuring the coolant temperature is arranged as the next component behind the coolant outlet of the aftercooler (22), which is in the flow direction of the Compressed air is arranged as the last air cooler in front of the air dryer (40).

7. Compressed air generating device (2.1, 2.3, 2.4, 2.5, 2.6, 2.7) according to one of claims 1 to 6, characterized in that the at least one electric motor (24), an inverter (26) influencing the operation of the electric motor (24), the two air compressors (16, 18), the intercooler (20), the aftercooler (22), the air dryer (40), the multi-circuit protection valve (50), which connects the outlet of the air dryer (40) with at least one external compressed air storage (45) and external compressed air consumers (51, 52) pneumatically connect, and a silencer (43) interact, but are arranged separately in relation to each other.

8. Compressed air generating device (2.2) according to one of claims 1 to 7, characterized in that the at least one electric motor (24), an inverter (26) influencing the operation of the electric motor (24), the two air compressors (16, 18), the Intercooler (20), the aftercooler (22), the air dryer (40), the multi-circuit protection valve (50), which pneumatically connects the outlet of the air dryer (40) with at least one external compressed air storage (45) and external compressed air consumers (51, 52), and a silencer (43) are arranged in or on a common housing (6).

9. Compressed air generating device (2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7) according to one of claims 1 to 8, characterized in that the control and regulating device (28) is arranged separately or in or on the housing (6). that the control and regulation device (28) is connected via a first control line (54) to the inverter (26) for controlling and regulating the electric motor (24), that the control and regulating device (28) via a second control line (55) with a 3/2 -Way magnetic switching valve (72) is connected, which is used to open or close a regeneration line (DL5a) that pneumatically at least indirectly connects the compressed air storage (45) and the air dryer (40), and that the control and regulating device (28) via a sensor line (56) is connected to the multi-circuit protection valve (50).

10. Compressed air generating device (2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7) according to one of claims 1 to 9, characterized in that the control and regulating device (28) in the inverter (26) or in the multi-circuit protection valve (50 ) is integrated.

11. Compressed air generating device according to one of claims 1 to 9, characterized in that the control and regulating device (28) is the central control and regulating device of a vehicle.

12. Compressed air generating device (2.3, 2.4, 2.5, 2.6, 2.7) according to one of claims 1 to 11, characterized in that in or on the housing (6) a compressor module (90), a compressed air cooling module (92), a dryer -Module (94) and a silencer module (96) together with associated pneumatic, hydraulic and electrical lines are arranged, the compressor module (90) containing the electric motor (24), the inverter (26), the two air compressors (16, 18) and the control and regulating device (28), the compressed air cooling module (92) having the intercooler (20) and the aftercooler (22), the dryer module (94) having the air dryer (40) and the multi-circuit protection valve (50), wherein the silencer module (96, 96*) has the silencer (43) with a sound-absorbing material (44), and in which the silencer module (96, 96*) has at least one regeneration air outlet opening (34). Discharge of regeneration compressed air into the environment.

13. Compressed air generating device (2.1, 2.2) according to one of claims 1 to 12, characterized in that the compressor module (90), the dryer module (94) and the silencer module (96*) are arranged one behind the other in this order are, and that the at least one air cooler (20) is integrated in the silencer (43) or in the silencer module (96*).

14. Compressed air generating device (2.1, 2.2) according to claim 13, characterized in that the intercooler (20) is integrated in the silencer (43).

15. Compressed air generating device (2.1, 2.2) according to claim 13, characterized in that the aftercooler (22) is integrated in the silencer (43).

16. Compressed air generating device (2.1, 2.2) according to claim 13, characterized in that the intercooler (20) and the aftercooler (22) are integrated in the silencer (43).

17. Compressed air generating device (2.2) according to one of claims 12 to 16, characterized in that the silencer (43) is designed without a water outlet opening (36), that one of the at least one compressor (18) to the at least one air cooler (20, 22) leading compressed air line (DL3) in a sump area (98) of the silencer (43) has a heating coil-shaped section (84) and is arranged in the sound-absorbing material (44) of the silencer (43) in such a way that the sound-absorbing material (44) during operation the compressed air generating device can be heated at least by the heating coil-shaped section (84).

18. Compressed air generating device (2.1) according to one of claims 12 to 16, characterized in that the silencer (43) is designed without a water outlet opening (36) that from the external cooling device (82) to the at least one air cooler (20, 22 ) leading coolant line (KL1) is guided through a sump area (98) of the silencer (43), and that the coolant line (KL1) is designed and arranged at least in this sump area (98) of the silencer (43) in such a way that during operation of the compressed air generating device the coolant line (KL1) can heat the sound-absorbing material (44) of the silencer (43) at an ambient temperature below the coolant temperature.

19. Compressed air generating device (2.2) according to one of the preceding claims 13 to 18, characterized in that the intercooler (20) and the aftercooler (22) are integrated into the silencer (43), that the first air compressor (16) is connected to the intercooler ( 20) is connected via a first compressed air line (DL1), that the intercooler (20) is connected to the second air compressor (18) via a second compressed air line (DL2), that the second air compressor (18) is connected via a third compressed air line (DL3). the aftercooler (22), that the aftercooler (22) is connected to the air dryer (40) via a fourth compressed air line (DL4), and that these compressed air lines (DL1, DL2, DL3, DL4) are designed in this way and in the silencer (43 ) are arranged so that by means of the warm compressed air guided through these compressed air lines (DL1, DL2, DL3, DL4), water (W) collected in the silencer (43) can be heated there to such an extent that this water (W) evaporates and comes out of the silencer (43 ) is deductible.

20. Compressed air generating device (2.3, 2.4, 2.5, 2.6), with at least one electric motor (24), with at least one air compressor (16, 18) that can be driven by the electric motor (24), with an air inlet (8 *), via which the Air compressor (16, 18) ambient air (L) can be sucked in, with at least one air cooler (20, 22), in which the air compressed by the air compressor (16, 18) can be cooled, with an air dryer (40), the inlet of which is connected to the The output of the at least one air cooler (20; 22) is connected to a coolant inlet opening (12), via which a liquid coolant can be supplied to the air cooler (20, 22), and to a coolant outlet opening (14), via which heated coolant can be removed, characterized in that the silencer (43) has at least one regeneration air outlet opening (34) for discharging regeneration exhaust air (AL) guided through it into the environment, that the at least one regeneration air outlet opening (34) when no regeneration of the desiccant (41) of the air dryer (40), serves as an air inlet (8*) for sucking in ambient air (L) to the at least one air compressor (16, 18), and that the ambient air (L) sucked in through the silencer (43) is downstream behind the Silencer (43) can be conducted through an intake air line (DL) to the at least one air compressor (16, 18).

21. Compressed air generating device (2.3, 2.4, 2.5, 2.6) according to claim 20, with at least one electric motor (24), with two air compressors (16, 18) which can be driven by the electric motor (24) and act one after the other, with an air inlet (8*). which ambient air (L) can be sucked in by means of the first air compressor (16), with an intercooler (20) and an aftercooler (22), the inlet of the intercooler (20) being pneumatically connected to the outlet of the first air compressor (16), whereby the output of the intercooler (20) is pneumatically connected to the input of the second air compressor (18), and wherein the output of the second air compressor (18) is pneumatically connected to the input of the aftercooler (22), with an air dryer (40), whose Inlet is connected to the outlet of the aftercooler (22), as well as to a coolant inlet opening (12), via which a liquid coolant can be supplied to the intercooler (20) and the aftercooler (22), and to a coolant outlet opening (14), via which heated Coolant can be removed, characterized in that the silencer (43) has at least one regeneration air outlet opening (34) for discharging regeneration exhaust air (AL) guided through it into the environment, that the at least one regeneration air outlet opening (34) when there is no regeneration of the The drying agent (41) of the air dryer (40) serves as an air inlet (8*) for sucking in ambient air (L) towards the first air compressor (18), and that the ambient air (L) sucked in through the silencer (43) is downstream behind the silencer (43) can be conducted to the first air compressor (16) through an intake air line (DL).

22. Compressed air generating device (2.4) according to one of the preceding claims, characterized in that a separator (88) for separating water and particles is arranged in front of or in the silencer (43), which is designed and arranged in such a way that with this through the at least one regeneration air outlet opening (34) which serves as an air inlet (8*) and the ambient air (L) sucked in can be freed from entrained water droplets and particles.

23. Compressed air generating device (2.5, 2.6), with at least one electric motor (24), with at least one air compressor (16, 18) which can be driven by the electric motor (24), with an air inlet (8, 8*), via which the air compressor ( 16, 18) Ambient air (L) can be sucked in, with at least one air cooler (20, 22), in which the air compressed by the air compressor (16, 18) can be cooled, with an air dryer (40), the inlet of which is connected to the outlet of the at least one air cooler ( 20, 22), with a coolant inlet opening (12), via which a liquid coolant can be supplied to the air cooler (20, 22), with a coolant outlet opening (14), via which heated coolant can be removed, with a multi-circuit protection valve (50), which pneumatically connects the output of the air dryer (40) with at least one external compressed air storage (45) and external compressed air consumers (51, 52), as well as with a control and regulating device (28), which is connected via at least one sensor line (56) to the multi-circuit protection valve ( 50) and sensors arranged there, characterized in that the multi-circuit protection valve (50) can be separated from the other components of the compressed air generating device and can be operated remotely from these components, that the control and regulating device (28) and the multi-circuit protection valve (50) have electrical connection means (64, 68), which are releasably connected to one another via at least one flexible electrical line (56), and that the multi-circuit protection valve (50) has pneumatic connecting means (62), which are at least indirectly via at least one flexible pneumatic line (DL5, 106). are detachably connected to the outlet of the air dryer (40).

24. Compressed air generating device (2.5, 2.6) according to claim 23, with at least one electric motor (24), with two air compressors (16, 18) which can be driven by the electric motor (24) and act one after the other, with an air inlet (8, 8 *). which ambient air (L) can be sucked in by means of the first air compressor (16), with an intercooler (20) and an aftercooler (22), the inlet of the intercooler (20) being pneumatically connected to the outlet of the first air compressor (16), whereby the output of the intercooler (20) is pneumatically connected to the input of the second air compressor (18), and wherein the output of the second air compressor (18) is pneumatically connected to the input of the aftercooler (22), with an air dryer (40), whose Inlet is connected to the outlet of the aftercooler (22), with a coolant inlet opening (12), via which a liquid coolant can be supplied to the intercooler (20) and the aftercooler (22), with a coolant outlet opening (14), via which heated coolant can be removed is, with a multi-circuit protection valve (50), which connects the outlet of the air dryer (40). pneumatically connects at least one external compressed air reservoir (45) and external compressed air consumers (51, 52), as well as with a control and regulating device (28), which is connected via at least one sensor line (56) to the multi-circuit protection valve (50) and sensors arranged there, characterized in that the multi-circuit protection valve (50) can be separated from the other components of the compressed air generating device and can be operated remotely from these components, that the control and regulating device (28) and the multi-circuit protection valve (50) have electrical connection means (64, 68), which via the at least one flexible electrical sensor line (56) are detachably connected to one another, and that the multi-circuit protection valve (50) has pneumatic connecting means (62) which are at least indirectly connected to the outlet of the air dryer (40) via at least one flexible pneumatic line (DL5, 106). are detachably connected.

25. Compressed air generating device (2.6) according to claim 24, characterized in that a dryer module (94) having the air dryer (40) has at least one electrical plug socket (100) and at least one pneumatic plug socket (104), that the electrical plug socket (100 ) of the dryer module (94) is connected to an electrical socket (68) on the control and regulating device (28) via the sensor line (56), so that an electrical plug is inserted into the electrical socket (100) of the dryer module (94). an electrical connecting line (102) can be releasably plugged in, that this electrical connecting line (102) has a second plug which can be releasably plugged into an electrical plug socket (64) of the multi-circuit protection valve (50), that the pneumatic plug socket (104) of the dryer module (94) is pneumatically connected to the fifth compressed air line (DL5), through which dried compressed air coming from the air dryer (40) can be conducted, so that a plug of a pneumatic connecting line (106) can be inserted into this pneumatic socket (104) of the dryer module (94). can be releasably plugged in, and that the pneumatic connecting line (106) has a second plug which can be releasably plugged into a pneumatic plug socket (62) of the multi-circuit protection valve (50).

26. Compressed air generating device (2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7), with at least one electric motor (24), with at least one drivable by the electric motor (24). Air compressor (16, 18), with an air inlet (8, 8*), through which ambient air (L) can be sucked in by means of the air compressor (16, 18), with at least one air cooler (20, 22), in which the air from the air compressor (16, 18) compressed air can be cooled, with an air dryer (40), with which compressed air can be dried, with a coolant inlet opening (12), via which a liquid coolant can be supplied to the air cooler (20, 22), with a coolant outlet opening ( 14), through which heated coolant can be removed, with a multi-circuit protection valve (50), which pneumatically connects the output of the air dryer (40) with at least one external compressed air storage (45) and with external compressed air consumers (51, 52), with an inverter (26 ), which is used to control and regulate the electric motor (24), and with a control and regulating device (28), which via at least one sensor line (56) with the multi-circuit protection valve (50) and sensors arranged there and with the inverter (26) is connected via at least one control line (54), characterized in that the control and regulating device (28) is an integral part of the inverter (26).

27. Compressed air generating device (2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7), with at least one electric motor (24), with two air compressors (16, 18) which can be driven by the electric motor (24) and act one after the other, with an air inlet ( 8, 8*), through which ambient air (L) can be sucked in by means of the first air compressor (16), with an intercooler (20) and an aftercooler (22), the inlet of the intercooler (20) being connected to the outlet of the first air compressor ( 16) is pneumatically connected, wherein the output of the intercooler (20) is pneumatically connected to the input of the second air compressor (18), and wherein the output of the second air compressor (18) is pneumatically connected to the input of the aftercooler (22), and with an air dryer (40), the inlet of which is connected to the outlet of the aftercooler (22), and with a coolant inlet opening (12), via which a liquid coolant can be supplied to the intercooler (20) and the aftercooler (22), with a coolant outlet opening (14), through which heated coolant can be removed, with a multi-circuit protection valve (50), which pneumatically connects the output of the air dryer (40) with at least one external compressed air storage (45) and with external compressed air consumers (51, 52), with an inverter ( 26), which is used to control and regulate the electric motor (24), and with a Control and regulating device (28), which is connected via at least one sensor line (56) to the multi-circuit protection valve (50) and sensors arranged there and to the inverter (26) via at least one control line (54), characterized in that the control and control device (28) is an integral part of the inverter (26).

28. Compressed air generating device (2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7), with at least one electric motor (24), with two air compressors (16, 18) that can be driven by the electric motor (24) and act one after the other, with an air inlet ( 8, 8*), through which ambient air (L) can be sucked in by means of the first air compressor (16), with an intercooler (20) and an aftercooler (22), the inlet of the intercooler (20) being connected to the outlet of the first air compressor ( 16) is pneumatically connected, wherein the output of the intercooler (20) is pneumatically connected to the input of the second air compressor (18), and wherein the output of the second air compressor (18) is pneumatically connected to the input of the aftercooler (22), and with an air dryer (40), the inlet of which is connected to the outlet of the aftercooler (22), and with a coolant inlet opening (12), via which a liquid coolant can be supplied to the intercooler (20) and the aftercooler (22), and with a Coolant outlet opening (14), through which heated coolant can be discharged, with a multi-circuit protection valve (50), which pneumatically connects the output of the air dryer (40) with at least one external compressed air reservoir (45) and with external compressed air consumers (51, 52), with an inverter (26), which is used to control and regulate the electric motor (24), and with a control and regulating device (28), which is connected via at least one sensor line (56) to sensors of the multi-circuit protection valve (50) and to the inverter (26 ) is connected via at least one control line (54), characterized in that the control and regulating device (28) is an integral part of the multi-circuit protection valve (50).

29. Compressed air generating device (2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7), with at least one electric motor (24), with two air compressors (16, 18) which can be driven by the electric motor (24) and act one after the other, with an air inlet ( 8, 8*), through which ambient air (L) can be sucked in by means of the first air compressor (16), with an intermediate cooler (20) and an aftercooler (22), the inlet of the intermediate cooling lers (20) is pneumatically connected to the output of the first air compressor (16), the output of the intercooler (20) being pneumatically connected to the input of the second air compressor (18), and wherein the output of the second air compressor (18) is connected to the The inlet of the aftercooler (22) is pneumatically connected, and with an air dryer (40), the inlet of which is connected to the outlet of the aftercooler (22), and with a coolant inlet opening (12), via which the intercooler (20) and the aftercooler ( 22) a liquid coolant can be supplied, and with a coolant outlet opening (14), through which heated coolant can be removed, with a multi-circuit protection valve (50), which connects the outlet of the air dryer (40) with at least one external compressed air storage (45) and with external compressed air consumers (51, 52) pneumatically connects, with an inverter (26), which is used to control and regulate the electric motor (24), and with a control and regulating device (28), which is connected via at least one sensor line (56) to the multi-circuit protection valve ( 50) and sensors arranged there and is connected to the inverter (26) via at least one control line (54), characterized in that the control and regulating device (28) is an integral part of a vehicle control device.

30. Method for operating the compressed air generating device (2.1 - 2.7) with the features of at least one of the device claims, wherein compressed air is cooled in at least one air cooler (20, 22) by means of the at least one air compressor (16, 18), this cooled compressed air is fed to an air dryer (40) and dried there, the dried compressed air being fed to compressed air consumers (51, 52) and/or at least one compressed air storage (45), and in which a desiccant (41) arranged in the air dryer (40) is regenerated. dry compressed air to the extent of a regeneration compressed air volume is passed through it and then discharged into the environment, characterized in that the regeneration compressed air volume necessary for the regeneration of the drying agent (41) is calculated at least as a function of the temperature at which the coolant is before and / or after flowing through of the air cooler (22), which is arranged as the last air cooler (22) in front of the air dryer (40), and that the regeneration compressed air volume of dry compressed air determined in this way is then passed through the air dryer (40).

31. Method according to claim 30, characterized in that the coolant temperature is measured in front of the coolant inlet opening (12, 12*) of the compressed air generating device (2) by means of a first temperature sensor (73), and that this is for drying the desiccant (41) in the air dryer (40 ) the required regeneration compressed air volume is passed through the air dryer (40) in a controlled and/or regulated manner depending on the measured coolant temperature.

32. The method according to claim 30, characterized in that the coolant temperature is measured directly in front of the coolant inlet of the air cooler (22) which is arranged as the last air cooler in front of the air dryer (40) in the flow direction of the compressed air by means of a second temperature sensor (73 '), and that the regeneration compressed air volume required for drying the desiccant (41) in the air dryer (40) is passed through the air dryer (40) in a controlled and/or regulated manner depending on the measured coolant temperature during a later regeneration process.

33. The method according to claim 30, characterized in that the coolant temperature is measured behind the coolant outlet of the air cooler (22) which is arranged as the last air cooler in front of the air dryer (40) in the direction of flow of the compressed air by means of a third temperature sensor (73”), and that the regeneration compressed air volume required for drying the desiccant (41) in the air dryer (40) is passed through the air dryer (40) in a controlled and/or regulated manner depending on the measured coolant temperature.

34. The method according to claim 30, characterized in that the temperature of an inverter (26) present for controlling and regulating the electric motor (24) is measured, that the measured temperature of the inverter (26) is used to calculate the coolant temperature in that air cooler (22). is used, which is arranged as the last air cooler (22) in front of the air dryer (40) in the direction of flow of the compressed air, and that for drying the desiccant (41) in the air dryer (40) the required regeneration compressed air volume is controlled and / or regulated through the air dryer (40) depending on the coolant temperature determined in this way.

35. Method for operating the compressed air generating device (2.1 - 2.7) with the features of at least one of the device claims and with the features of at least one of the method claims 30 to 34, characterized by the following method steps: a) sucking in ambient air by means of the first air compressor (16 ), b) pre-compressing the sucked-in ambient air in the first air compressor (16) to a first air pressure value, c) cooling an intercooler (20) with a liquid coolant, d) cooling the pre-compressed compressed air in the intercooler (20), e) further compressing the compressed air to a second, higher pressure value by means of a second air compressor (18), f) cooling an aftercooler (22) with the liquid coolant, the aftercooler (22), viewed in the flow direction of the coolant, being the first air cooler to be reached hydraulically by the coolant, g) cooling the compressed air further compressed in the second air compressor (18) in the aftercooler (22), h) drying the cooled compressed air in an air dryer (40), i) forwarding the cooled and dried compressed air to compressed air consumers (51, 52) and /or to at least one compressed air reservoir (45), j) forwarding the liquid coolant from the aftercooler (22) to the intercooler (20), k) forwarding the liquid coolant from the intercooler (20) to a cooling device (25) of the electric motor ( 24), l) forwarding the liquid coolant from the cooling device (25) of the electric motor (24) to a cooling device (48) of the second air compressor (18), m) forwarding the liquid coolant from the cooling device (48) of the second air compressor (18 ) to a cooling device (27) of the inverter (26), n) forwarding the liquid coolant from the cooling device (27) of the inverter (26) to a cooling device (46) of the first air compressor (18), o) forwarding the liquid coolant from the cooling device (46) of the first air compressor (18) to an external cooling device (82).

36. The method according to one of claims 30 to 35, characterized in that the time interval between two regeneration processes for drying the drying agent (41) of the air dryer (40) is controlled and / or regulated depending on the temperature of the coolant during a later regeneration process , which has the coolant at the outlet of the external cooling device (82) or at the inlet of the aftercooler (22).

37. The method according to one of claims 30 to 36, characterized in that the time interval between two regeneration processes for drying the desiccant (41) of the air dryer (40) is controlled and / or regulated as a function of the ambient temperature during a later regeneration process.

38. The method according to one of claims 30 to 37, characterized in that the regeneration compressed air volume required for drying the drying agent (41) is controlled and / or regulated depending on the ambient temperature during a later regeneration process.

39. The method according to any one of claims 30 to 38, characterized in that the regeneration compressed air volume required for drying the drying agent (41) or the duration and / or frequency of the regeneration processes depends on the difference between the ambient temperature and the coolant temperature during a later Regeneration process is controlled and / or regulated.

40. The method according to one of claims 30 to 39, characterized in that with an unregulated control of the regeneration of the drying agent (41) of the air dryer (40), a maximum high temperature value of the coolant to be expected during operation of the compressed air generating device (2.1 - 2.7) is determined that this value of the coolant temperature serves as the basis for determining a maximum regeneration compressed air volume, and that a relevant one Regeneration process for the drying agent (41) is carried out with this maximum regeneration compressed air volume.