EP3601797B1 - Reciprocating compressor with an extended control range - Google Patents

Description

The invention relates to a piston compressor with at least one cylinder for compressing air with a piston arranged movably therein in a compression chamber arranged above the piston in the cylinder, which is connected to an inlet arrangement for air to be compressed and to an outlet arrangement for compressed air.

Piston compressors, such as, in particular, oil-free piston compressors for rail vehicles, are used to fill compressed air tanks from which compressed air is withdrawn, in particular, at irregular intervals. The piston compressors are usually dimensioned for the filling operation, in which a pressure vessel is to be filled up quickly, which is why a maximum volume flow is made available. For normal operation, in which the compressor may be operated for a short period of time after long intermittent periods and only to refill the compressed air that has been withdrawn, operation with maximum volume flow means a rather unfavorable operating state that could be avoided if the delivery capacity of such piston compressors was regulated according to requirements.

The controllability of known piston compressors is limited by the design-related maximum and minimum speeds. The upper speed limit of, in particular, oil-free, dry-running piston compressors is limited by the maximum relative speed of dry-running sliding pairs. At low speeds, on the other hand, vibrations occur due to free inertia forces in the piston compressor, which also limits the lower speed when operating a piston compressor. This results in only a slight variability in the speed of reciprocating compressors, which in most applications requires the delivery of compressed air in intermittent operation.

In known reciprocating compressors, the interruption control of the compressed air delivery is implemented in that the compressor is switched to standstill as soon as the System pressure has reached the cut-out pressure. If the system pressure then falls to the switch-on pressure, in particular due to the withdrawal of compressed air, the piston compressor is switched to load operation, in which it delivers a maximum volume flow at the nominal speed. Unless larger amounts of compressed air are taken from the compressed air tank or the compressed air system at the same time, the compressed air tank fills up relatively quickly, so that the piston compressor is switched off again for a long time after a short switch-on time. The control spectrum of this known solution is therefore limited to standstill and running under load and is unfavorable and even unsuitable for certain operating conditions due to the associated cold start as well as the higher wear and the longer downtimes of the piston compressor.

In an alternative embodiment of a reciprocating compressor, intermittent operation is implemented at various predefined speeds, for example by switching the motor between four and six poles or by an inverter that can be switched between 50 Hz and 60 Hz. However, only a relatively limited control range can be implemented with the respective compressor due to the motor speeds specified in this process. Here, too, high engine speeds cause a high thermal load, particularly on oil-free sliding pairs, which significantly reduces the service life of a piston compressor. Although the solution is a simple approach to regulating the volume flow, the control spectrum is limited by the fixed motor speeds and, under certain operating conditions, the changeover cannot generate a sufficient volume flow.

From the published documents of the German patent applications DE 10 2013 113 555 and DE 10 2013 113 556 a compressor system and a method for operating the compressor system as a function of the operating state of a rail vehicle or as a function of the current situation of a rail vehicle are known, in which an actuator is arranged for continuously influencing the speed of the electric drive device of the piston compressor, the control of the Actuator takes place via a control device. The actuator allows the operation of the drive device and thus the piston compressor by different Adapt speeds to the current operating state or to the current situation of the rail vehicle.

In addition, AT 135585 discloses a method for cooling gaseous media, according to which the gas is compressed in two stages, optionally with the interposition of a cooling device, whereupon the compressed gas flows to an expansion machine via a cooling device.

the US 2005/0220628 A1 relates to a method for checking a compressor system for malfunctions. The compressor system cited for this purpose comprises two parallel low-pressure cylinders which are connected upstream of a high-pressure cylinder.

The invention is therefore based on the object of providing an improved reciprocating compressor with a larger control range of the delivery rate while improving the energy efficiency and power density.

To achieve this object, a piston compressor according to claim 1 and a method for controlling such a piston compressor according to claim 6 are proposed. Developments of the proposed solutions are the subject of the respective dependent claims.

To achieve the object, a piston compressor with at least one cylinder for compressing air with a piston arranged movably therein in a compression space arranged above the piston in the cylinder is proposed. The compression space has an air inlet and an air outlet and is connected at the air inlet to an inlet arrangement for air to be compressed and is connected to an outlet arrangement for compressed air at the air outlet. The piston compressor can be driven by a first drive device. The inlet arrangement has a pre-compression device, which can be driven by a second drive device with variable power, for increasing the intake pressure and a cooling device for cooling the air to be compressed.

The proposed solution makes it possible to increase the volume flow of a reciprocating compressor through the increased intake pressure and the reduced intake temperature of the intake air, whereby its delivery capacity increases.

The piston compressor is a known type of piston compressor with a cylinder in which a piston arranged therein is axially movable and in a reciprocating motion sucks in air to be compressed, in particular via an inlet valve arranged at the air inlet, compresses it from an inlet arrangement and in particular via an air outlet discharges arranged outlet valve against a pressure in an outlet arrangement. The piston compressor is one of the first Drive device drivable. Depending on the application of the piston compressor, the first drive device is an internal combustion engine, an electric drive device or another suitable drive device.

A piston compressor according to the invention can be both a dry-running, that is to say oil-free, piston compressor and a piston compressor that is not designed to be oil-free. Although advantages or embodiments are also described within the scope of the invention which cannot be used for piston compressors other than dry running, other advantages and embodiments can also be used independently of this for piston compressors which are not running dry.

In the proposed piston compressor, the inlet arrangement has a pre-compression device that can be driven by a second drive device with variable power. With this pre-compression device, the intake pressure, in particular at the air inlet, can be increased variably from an output _{pressure p 0} up to a maximum pressure p _max due to the variable power. The higher suction pressure of the first cylinder in multi-stage piston compressors or the single cylinder in single-stage piston compressors increases the volume flow by ΔV, since the compression chamber of the cylinder is filled with air that is to be compressed under higher pressure.

The second drive device, which is used to drive the pre-compression device, can also be an electric drive device or another suitable drive device, depending on the application. Likewise, the drive power of the second drive device can also be transferred to the first drive device or another available drive device, for example by means of a gear with a variable ratio. In particular, the power transmitted by the second drive device can be variably adjusted.

In the proposed solution, the inlet arrangement has a cooling device through which the air to be compressed, which flows through the inlet arrangement suitable measures cool. In this case, the cooling device is arranged in particular in the flow direction of the intake air after the pre-compression device, since the air is heated by the pre-compression. However, it is also possible to arrange a cooling device upstream of the pre-compression device in the direction of flow, in particular if this is advantageous due to structural conditions. With this arrangement, a greater reduction in temperature is necessary, since the air temperature increases again as a result of the pre-compression. In one embodiment of the piston compressor it can also be provided that the intake air is cooled before and after the pre-compression.

The inlet arrangement in particular also has at least one conduit device which directs the intake air to the at least one cooling device and to the at least one compression device and connects them to one another and / or to the air inlet of the compression chamber. In particular, a cooling device can also be arranged on the outside of a line device. Suitable cooling devices of the inlet arrangement can be, for example, coolant heat exchangers or devices for enlarging the outer surface of the inlet arrangement or a line device such as line loops or cooling fins, which are used, for example, in connection with fans, or any other suitable type of device by means of which the flowing in the inlet arrangement Intake air heat energy can be withdrawn.

der Vorverdichtungseinrichtung zu erhöhen. Durch den erhöhten Ansaugdruck und die reduzierte Ansaugtemperatur der Ansaugluft steigt die Lieferleistung des Kolbenkompressors. Die veränderbare Leistung der Vorverdichtungseinrichtung ermöglicht in Verbindung mit der Leistungssteigerung des Kolbenkompressors ein nach oben hin breiteres Regelspektrum des Kolbenkompressors. So wird auch die Verwendung von Kolbenkompressoren mit insgesamt kleinerer Baugröße möglich, da durch den erhöhten Ansaugdruck höhere Volumenströme realisiert werden. Die vorgeschlagene Lösung ermöglicht einen geregelten Kompressorbetrieb mit kurzzeitig sehr hoher Leistung beim Auffüllbetrieb (großer Volumenstrom des Kolbenkompressors) und einen konstanter Betrieb mit niedriger Leistung (geringerer Volumenstrom des Kolbenkompressors) im Regelbetrieb. Damit besteht keine Gefahr von Vibrationen durch freie Massenkräfte bei niedrigen Drehzahlen und die maximalen Relativgeschwindigkeiten von insbesondere ölfreien Gleitpaarungen können eingehalten werden. Zudem kann durch die vorgeschlagene Lösung das Gesamttemperaturniveau eines Kolbenkompressors gesenkt werden.The proposed solution makes it possible to increase the volume flow of a reciprocating compressor by the factor $\frac{p_{\mathit{Max}}}{p_0}$

to increase the pre-compression device. The delivery capacity of the piston compressor increases due to the increased intake pressure and the reduced intake temperature of the intake air. The variable output of the pre-compression device, in conjunction with the increase in output of the piston compressor, enables the piston compressor to have a broader control range towards the top. This also makes it possible to use piston compressors with a smaller overall size, since higher volume flows are achieved due to the increased suction pressure. The proposed solution enables regulated compressor operation with briefly very high performance in the filling operation (large volume flow of the piston compressor) and constant operation with low power (lower volume flow of the piston compressor) in normal operation. This means that there is no risk of vibrations due to free inertia forces at low speeds and the maximum relative speeds of, in particular, oil-free sliding pairs can be maintained. In addition, the proposed solution can lower the overall temperature level of a reciprocating compressor.

The proposed solution thus increases the control range of the volume flow and thus the delivery capacity of a compressor, leads to a reduction in relevant temperature levels and at the same time increases the energy efficiency and power density of the piston compressor.

The piston compressor is driven by a crankshaft which is rotatably mounted in a crankcase. One or more connecting rods, each connected to a piston, are rotatably mounted at an eccentric position of the crankshaft in such a way that their rotational movement is transmitted as a stroke movement to the piston moving axially in a cylinder. The piston compressor has at least one cylinder for compressing air, but can also have two or more cylinders arranged one after the other or in parallel, which are provided for compressing air by means of a piston movably arranged therein, so that the piston compressor can be designed in one or more stages can.

The piston compressor also has a crankcase in which a crankshaft is arranged, on which at least one connecting rod connected to a piston is rotatably mounted, the intake air of the at least one cylinder being guided through the crankcase.

As a result, the intake air of the at least one cylinder is guided through the crankcase, flowing over the elements of the crank drive, essentially the crankshaft, the connecting rods, the underside of the piston or pistons and the bearing elements arranged in between, and cooling them in the process. The intake air is essentially the air that is later sucked into the at least one cylinder of the piston compressor and compressed there.

In one embodiment of the reciprocating compressor, the inlet arrangement has an air discharge device. This embodiment makes it possible to guide a larger volume flow through the crankcase than is later received as intake air in the at least one cylinder of the piston compressor and is compressed there. In this way, the volume flow of cooling air in the crankcase can be increased and, at the same time, the heating of the intake air as it flows through the crankcase can be reduced.

The air diverting device can be designed, for example, in the form of a check valve or pressure relief valve, which opens from a predetermined pressure of the intake air. The air discharge device can, however, also be designed in such a way that it can be opened and closed depending on predetermined parameter values, in particular by a control device. In one embodiment of an air discharge device, in particular excess intake air is discharged from the inlet arrangement into the environment; in another embodiment of an air discharge device, for example, a predetermined proportion of the cooled volume flow of the intake air can be returned to the crankcase.

In a further embodiment of the piston compressor, an after-cooling device is arranged for cooling the compressed air after it has passed through the at least one cylinder of the piston compressor. In particular, the outlet arrangement has an after-cooling device for cooling the compressed air. As a result of the compression, the air in the cylinder is heated, so that the compressed air expelled from the compression chamber through the air outlet has an increased temperature. Cooling the compressed air after it has passed through the at least one cylinder by means of at least one after-cooling device of the outlet arrangement simplifies, for example, a subsequent storage of the air or further processing such as e.g. B. dehumidifying the air. In one embodiment of the reciprocating compressor, the after-cooling device of the outlet arrangement is formed by a partition of the cooling device for cooling the intake air of the inlet arrangement.

In a further embodiment, the piston compressor has a regulating device with which the output of the pre-compression device and thus the suction pressure at the air inlet can be regulated, in particular continuously. The control device is operatively connected to the second drive device, which drives the pre-compression device with variable power. The control device receives signals and / or measured values which are in particular related to the required delivery capacity of the piston compressor and by means of which the control device adjusts the output of the second drive device and thus the pre-compression device. In this way, the degree of pre-compression of the air flowing through the inlet arrangement into the cylinder is regulated by means of the pre-compression device.

To achieve the object, a method for controlling a reciprocating compressor of the type described above is also proposed, wherein the regulating device adjusts the performance of the pre-compression device between a maximum value that _{corresponds to a maximum suction pressure (p max} ) at the air inlet and a minimum value that corresponds to that caused by the Piston stroke movement in the cylinder _{corresponds to suction pressure (p 0} ) at the air inlet, regulates. The delivery performance of the piston compressor can thus be adjusted, in particular steplessly, by the method according to the invention in an extended control range between a maximum intake pressure and a minimum intake pressure at the air inlet. In this way, the control range of the volume flow of the compressor is expanded, whereby the energy efficiency and the power density are increased.

In one embodiment of the method for controlling the piston compressor, the regulating device is signal-connected to at least one signal transmitter and / or at least one sensor, the regulating device measuring the performance of the pre-compression device as a function of at least one value and / or signal from this at least one signal transmitter and / or sensor regulates. The control device receives relevant values or signals for the currently required delivery capacity of the piston compressor from at least one sensor and / or at least one signal transmitter, from which the control device determines the currently required volume flow and the output of the Pre-compression device regulates according to this need. In this way, the control device can be used to adapt the volume flow of the piston compressor, for example, depending on a current requirement, the operating state or the current situation of the system having the compressor, such as a rail vehicle.

In a further embodiment of the method, the control device receives values from at least one sensor. For this purpose, the at least one sensor is selected from a group which in particular has pressure sensors, temperature sensors, volume flow sensors, speed sensors or other suitable sensors. These sensors record relevant parameter values in particular for the regulation of the pre-compression device. A suitable pressure sensor detects, for example, the pressure in the pressure system supplied by the piston compressor. This can be positioned, for example, on the outlet arrangement before or after an after-cooling device, which may be arranged there, or in the compressed air tank. Depending on the pressure value recorded in the compressed air system, it may be necessary to fill up quickly, with a high delivery rate of the reciprocating compressor being required, or to refill smaller amounts of extracted compressed air, which can be done more economically with a lower delivery rate.

The volume flow taken from the compressed air system can be recorded directly by means of a volume flow sensor. This value also influences, for example, the amount of compressed air required when the piston compressor is being refilled. By means of a speed sensor, which transmits the speed of the crankshaft to the regulating device, a value for the volume flow which flows through the intake arrangement can be derived in the method for controlling the piston compressor. With a temperature sensor, for example, the air temperature in the crankcase, in the inlet arrangement, in the outlet arrangement or in the compressed air system can be detected, from which different requirements for the delivery capacity of the piston compressor can also be derived, which can be adjusted with the help of the control device.

In one embodiment of the method for controlling a reciprocating compressor, the regulating device is signal-connected to at least one signal transmitter, which is selected from a group which has operating management systems, control devices such as a control device of the first drive device or other suitable devices that process information that are relevant for controlling the delivery capacity of the reciprocating compressor. From a vehicle management system, a control device for a reciprocating compressor receives, for example, values relating to the current operating state of a vehicle, such as the driving speed, braking operation or route operation and the like, from which the current compressed air consumption and the currently required level of the compressed air system can be derived. Based on signals from the control device of the first drive device, the control device can derive information regarding the current operating situation and the operating state of the system in which the piston compressor is currently being used and can determine and apply control values for the required volume flow of the piston compressor from this.

In one embodiment of the method for controlling a reciprocating compressor, the regulating device regulates the output of the cooling device independently of the output of the pre-compression device. The setpoint values for the output of the cooling device can be transmitted directly to the control device. Likewise, the control device can also determine the setpoint to be adjusted, in particular as a function of sensor or signal transmitter values, which contain, for example, the temperature of the environment, in the crankcase or in the compressed air tank. A greater or lesser cooling capacity of the cooling device may be required, regardless of the capacity of the pre-compression device, for example to bring about greater or lesser compression of the air in the reciprocating compressor, or to indirectly increase the temperature level of the pressure system through a lower or higher temperature of the intake air of the reciprocating compressor influence.

• Fig. 1 zeigt eine schematische Darstellung einer ersten Ausführungsform eines beispielhaften erfindungsgemäßen Kolbenkompressors;
• Fig. 2 zeigt eine schematische Darstellung einer zweiten Ausführungsform eines beispielhaften erfindungsgemäßen Kolbenkompressors; und
• Fig. 3 zeigt ein Diagramm, in dem die Volumenstromänderung durch die Erhöhung des Eingangsdrucks dargestellt ist.

Further advantages, features and possible applications of the present invention emerge from the following description in connection with the figures.

• Fig. 1 shows a schematic representation of a first embodiment of an exemplary piston compressor according to the invention;
• Fig. 2 shows a schematic representation of a second embodiment of an exemplary piston compressor according to the invention; and
• Fig. 3 shows a diagram in which the change in volume flow due to the increase in the inlet pressure is shown.

Fig. 1 3 shows a schematic representation of a first embodiment of an exemplary piston compressor 10 according to the invention. The piston compressor 10 shown in one stage in the exemplary embodiment has a cylinder 11 with a compression chamber 14 for compressing air by means of a piston 12 arranged in the cylinder 11, which is driven via a connecting rod 13 rotatably mounted eccentrically on the crankshaft 21.

The cylinder 11 has an air inlet 30, which is connected to an inlet arrangement 31, which guides air to be compressed to the air inlet 30 of the compression chamber 14. Furthermore, the cylinder 11 has an air outlet 33 which is connected to an outlet arrangement 34 which takes up compressed air from the compression chamber 14. The crankshaft 21, together with the connecting rod 13 and the bearings arranged on these and between them, forms the crankshaft drive 15, which heats up inside the crankcase 20 when the piston compressor 10 is in operation.

The crankcase 20 of the exemplary embodiment is connected via an air supply line 25 to an air filter 26, via which ambient air is sucked in and is fed into the crankcase 20 via the air supply line 25. The inlet arrangement 31 is arranged at a region of the crankcase 20 remote from the connection of the air supply line 25, so that the Air guided by the air supply line 25 into the crankcase 20 can leave the crankcase 20 again through the inlet arrangement 31 after flowing through the crankcase 20. The air flow formed in this way flows over in particular the elements of the crank drive 15 and absorbs thermal energy while cooling the crank drive 15 at the same time.

The inlet arrangement 31 has a pre-compression device 28 in the form of an external high-performance fan which is driven by a pre-compressor drive (second drive device) 29. As a result of the action of the pre-compression device 28, ambient air is sucked through the air filter 26 into the crankcase 20, where it flows over the elements of the crank drive 15 and thereby extracts thermal energy from them. The pre-compression device 28 sucks the heated air into the inlet arrangement 31 after it has flowed through the crankcase 20, compresses it and, depending on the current output of the pre-compressor drive 29, builds up a pressure that is higher than the ambient pressure at the air inlet 30 in front of the cylinder 11. As a result of this increased pressure at the air inlet 30, more air can flow into the compression chamber 14 during an intake stroke of the piston 12, as a result of which the delivery performance and the efficiency of the piston compressor 10 are increased.

In the exemplary embodiment of Fig. 1 the inlet arrangement 31 has a cooling device 32 between the pre-compression device 28 and the cylinder 11, which cools the air flowing through the inlet arrangement 31. Both when flowing through the crankcase 20 and through the pre-compression in the pre-compression device 28, the intake air heats up, which leads to an increase in volume which causes a reduction in the amount of air that can be absorbed into the compression chamber 14 during an intake stroke. In order to counteract this effect, the inlet arrangement 31 has, in the flow direction of the intake air, after the pre-compression device 28, a cooling device 32 which cools the pre-compressed intake air. As a result, a larger amount of air can be taken up in the compression chamber 14. This measure further increases the delivery performance and efficiency of the reciprocating compressor 10.

In the exemplary embodiment of the piston compressor 10, the pre-compressor drive 29 is connected to a control device 40 which regulates the output of the pre-compression device 28 and thus the suction pressure at the air inlet 31. Several pressure sensors 41a, 41b, 41c and several temperature sensors 42a, 42b, 42c are arranged at suitable points on the inlet arrangement 31 and on the outlet arrangement 34 of the reciprocating compressor 10, each of which is signal-connected to the control device 40 (not shown). The pressure sensors 41a, 41b, 41c and the temperature sensors 42a, 42b, 42c transmit the respective prevailing air temperature or the pressure at their respective position on the inlet arrangement 31 or on the outlet arrangement 34 to the control device 40.

Furthermore, the control device 40 is signal-connected to a device management system 45, which transmits further data relevant to the compressed air supply to the reciprocating compressor 10 to the control device 40. From the data that the control device 40 receives, in particular from the pressure sensors 41a, 41b, 41c, the temperature sensors 42a, 42b, 42c and from the device management system 45, the control device 40 determines the current requirement of the compressed air supply system and thus the required delivery capacity of the piston compressor 10 The control device 40 adapts the degree of pre-compression of the intake air at the air inlet 31 by means of the pre-compression device 28 to the demand requirement resulting therefrom by suitable regulation of the pre-compressor drive 29.

In a further exemplary embodiment, not shown, of the piston compressor 10 according to the invention, a power control of the cooling device 32 and of the post-cooling device 35 is also connected to the regulating device 40. In this case, the cooling output of the two cooling devices 32, 35 can then also be regulated by means of the regulating device 40 to a required cooling output, in particular determined in each case.

Fig. 2 shows a schematic representation of a second embodiment of an exemplary piston compressor 10 according to the invention. The piston compressor 10 the end Fig. 2 largely corresponds to that in Fig. 1 piston compressor 10 illustrated and described for this purpose, so that the same elements of the piston compressors 10 are denoted by the same reference numerals. In the following, only the differences between the two piston compressors 10 shown schematically are explained.

The in Fig. 2 The piston compressor 10 shown has opposite the piston compressor 10 Fig. 1 an air discharge device 36 arranged on the inlet arrangement 31 in the form of a pressure relief valve. In the embodiment shown, the pressure relief valve of the air discharge device 36 opens as soon as the pressure in the inlet arrangement 31 in the flow direction of the intake air after the cooling device 32 exceeds a predetermined value and discharges the excess intake air in the inlet arrangement 31 to the surroundings of the reciprocating compressor 10. In this way, the volume flow of air for cooling the crankcase 20 can be greater than the delivery rate of the reciprocating compressor 10, since the excess air can be discharged from the inlet arrangement 31 after flowing through the crankcase 20 and after the pre-compression.

In this exemplary embodiment, a largely arbitrarily large air volume flow through the crankcase 20 can be achieved, the cooling device 32 possibly being off opposite the reciprocating compressor 10 Fig. 1 is to be designed larger for the increased volume flow. When compared with the piston compressor 10 from Fig. 1 With the same delivery rate, the amount of air drawn in through the air filter 26 also increases.

Fig. 3 FIG. 8 shows a diagram which illustrates the change in the volume flow delivered by the reciprocating compressor 10 due to a precompression and cooling of the intake air as it flows through the inlet arrangement 31. The diagram shows the pressure of the intake air at the air inlet 30 over the volume flow conveyed by the piston compressor 10.

The volume flow 51 conveyed by a piston compressor 10 according to the prior art is shown by a curve shown in dashed lines. The one from one The volume flow 52 conveyed by the piston compressor 10 according to the invention is illustrated by a curve shown continuously.

As can be seen from the diagram, increasing the intake pressure p _e0 by Δp _e to p _{e1 increases the volume flow by ΔV to V 1} through the pre-compression and cooling of the intake air, since the displacement of the compression chamber V ₀ with a larger amount of air than is filled in a piston compressor 10 according to the prior art.

The features of the invention disclosed in the above description, in the drawings and in the claims can be essential for realizing the invention both individually and in any combination.

REFERENCE LIST

10

Reciprocating compressor

11

cylinder

12th

Pistons

13th

Connecting rod

14th

Compression space

15th

Crank drive

20th

Crankcase

21

crankshaft

22nd

first drive device

25th

Air supply line

26th

Air filter

28

Pre-compression device

29

Pre-compressor drive

30th

Air inlet

31

Inlet arrangement

32

Cooling device

33

Air outlet

34

Outlet arrangement

35

Post-cooling device

36

Air deflector

40

Control device

41a, b, c

Pressure sensor

42a, b, c

Temperature sensor

45

Device management system

51

Volume flow of a piston compressor of the prior art

52

Volume flow of a piston compressor according to the invention

Claims (9)

1. Piston compressor comprising at least one cylinder (11) for compressing air with a piston (12), which is arranged movably therein, in a compression chamber (14) arranged above the piston (12) in the cylinder (11), wherein the compression chamber (14) has an air inlet (30) and an air outlet (33) and is connected at the air inlet (30) to an inlet arrangement (31) for air to be compressed and is connected at the air outlet (33) to an outlet arrangement (34) for compressed air, wherein the piston compressor (10) is drivable by a first drive device (22), characterized in that the inlet arrangement (31) has a pre-compression device (28), which is drivable with variable power by a second drive device (29), for increasing the intake pressure, and a cooling device (32) for cooling the air to be compressed, and wherein the piston compressor comprises a crankcase (22) in which a crankshaft (21) is arranged, on which at least one connecting rod (13) which is connected to a piston (12) is rotatably mounted, wherein the intake air of the at least one cylinder (11) is guided through the crankcase (20) .
2. Piston compressor according to Claim 1, characterized in that the inlet arrangement (31) has an air-diverting device (36).
3. Piston compressor according to either of the preceding claims, characterized by an after-cooling device (35) for cooling the compressed air after passage through the at least one cylinder (11) of the piston compressor (10).
4. Piston compressor according to one of the preceding claims, characterized by a regulating device (40) with which the power of the pre-compression device (28) and thus the intake pressure at the air inlet (30) can be regulated.
5. Method for controlling a piston compressor according to Claim 4, characterized in that the regulating device (40) regulates the power of the pre-compression device (28) between a maximum value, which corresponds to a maximum intake pressure (p_max) at the air inlet (30), and a minimum value, which corresponds to the intake pressure (p₀), which is produced by the piston stroke movement in the cylinder (11), at the air inlet (30).
6. Method for controlling a piston compressor according to Claim 5, characterized in that the regulating device (40) is connected in terms of signalling to at least one signal transmitter (45) and/or at least one sensor (41a, 41b, 41c, 42a, 42b, 42c), wherein the regulating device (40) regulates the power of the pre-compression device (28) depending on at least one value and/or signal from said at least one signal transmitter (45) and/or sensor (41a, 41b, 41c, 42a, 42b, 42c).
7. Method for controlling a piston compressor according to Claim 6, characterized in that the at least one sensor (41a, 41b, 41c, 42a, 42b, 42c) is selected from a group which in particular comprises pressure sensors (41a, 41b, 41c), temperature sensors (42a, 42b, 42c), volumetric flow sensors and rotational speed sensors.
8. Method for controlling a piston compressor according to Claim 6 or 7, characterized in that the at least one signal transmitter (45) is selected from a group which in particular comprises operating management systems (45) or control devices.
9. Method for controlling a piston compressor according to one of Claims 5 to 8, characterized in that the regulating device (40) regulates the power of the cooling device (32) independently of the power of the pre-compression device (28).

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