DE102004023581A1 - Clutch controlling method for motor vehicle gear, involves evaluating temperature of clutch and comparing temperature with temperature threshold value, where control unit is substitution strategy for starting vehicle - Google Patents

Abstract

The method involves evaluating temperature of a clutch, which is estimated after starting a vehicle, and comparing the temperature with a temperature threshold value before starting the vehicle. A control unit is a substitution strategy for starting the vehicle when the temperature reaches the temperature threshold value. The substitution strategy assigns a permissible engine moment for starting the vehicle. Independent claims are also included for the following: (A) a motor vehicle comprising a control unit (B) a computer program product implementing a process for controlling a clutch.

Description

The The invention relates to a method for controlling a control unit directly or indirectly connected clutch and / or a motor vehicle transmission, a control unit in which such a method is integrated, a motor vehicle and a computer program product for the execution of said Process.

It It is well known that on many journeys of the motor vehicle within a short time extreme heating of the clutch, in particular The clutch documents may occur. For example, in dry clutches Clutch wear increases exponentially to the coupling temperature, which, if necessary, to destroy the Guide clutch friction documents can. In wet (multi-plate) couplings, it may also be a very large heat input come into the medium used (usually oil). To avoid this, it is known corresponding cooling devices to use.

In the DE 198 15 259 is a device for controlling an automated clutch in the drive train, described with an activatable by a control unit operating unit for adjusting the transmittable torque of the clutch. The control unit is in signal communication with sensors and other electronic units, for example via signal lines and / or a data bus, wherein the control unit calculates or determines the clutch slip in the region of Kupplungsreibbelege and determined by means of the clutch slip and based on the transferable torque of the clutch energy input of Kupplungsreibbelege and / / or determines a temperature increase of the friction pads and / or determines an increased wear of the friction pads. In a comparison with a limit value increased energy input or at an increased temperature increase compared to a limit and / or increased wear compared to a limit, the control unit controls in a first time phase of the time t _1, the transferable clutch torque unaffected by the energy input , Subsequently, in a second time phase of the time duration t ₂ , the control unit controls the torque transmittable by the clutch in a time-variable manner, such as pulsating, and in a third time phase of the time duration t ₃ increases the torque transmittable by the clutch until the engine speed falls below a threshold value or until the time t _{3 has} expired. One of the major disadvantages is that in the second time phase due to the time-varying torque, there is a jerking of the vehicle, which significantly worsens the ride comfort.

task The invention is a method for controlling the clutch and / or of the motor vehicle transmission, in which the above Disadvantages are avoided, in particular a reliable and comfortable starting of the motor vehicle is achieved, wherein at the same time a clutch wear as well the fuel consumption is kept low.

Farther It is an object of the invention to provide a motor vehicle with an above To provide a method which over the prior art of Technology increased Operating safety.

The The object is achieved by a method having the features of the claim 1 solved. In the dependent claims preferred developments are listed.

Calculated according to the invention the control unit, which can be in signal communication with sensors, before each arrival of the motor vehicle to be expected after the journey Temperature of the coupling in dependence of various input variables. The Expected temperature is then followed by a temperature limit compared, for example, stored in the control unit can be. If the expected temperature after starting the Reaches or exceeds the temperature limit, selects Control unit a replacement strategy for the approach of the motor vehicle out. Thus, the control unit calculates before each arrival of the motor vehicle the expected clutch temperature at the end of the upcoming Directions. For this purpose, the expected energy input into the coupling, in particular in the Kupplungsreibbelege, on the basis of various input variables determined. by virtue of the calculated energy input can be the temperature of the clutch friction documents to be determined after the journey. With the input variables can these are a variety of parameters that are also in the control unit can be stored, or the current while of the operation of the motor vehicle.

The parameters stored in the control unit may be, for example, values that include the geometry of the clutch. The current parameters may be, for example, the current temperature of the Kupplungsreibbelages and / or the degree of actuation of the load lever (accelerator pedal). If the expected temperature after starting is less than that of the temperature limit, the motor vehicle is approached according to the input variables. This means that according to the position of the accelerator pedal the approach of the motor vehicle takes place. First if the expected temperature reaches or exceeds the temperature limit, the control unit selects a replacement strategy for the approach of the motor vehicle. Here, the replacement strategy is mainly used to protect the clutch to prevent increased wear of the friction pads or destruction of the friction pads as far as possible.

at the clutch may be, for example, a friction clutch, Dry friction clutch, multi-plate clutch, magnetic powder clutch or torque converter lockup clutch act that can be addressed by the control unit. Further The invention relates to both manual transmission (spur gear etc.) as well as on automatic transmission, which is the manual transmission can be about an automated transmission.

In order to the control unit the necessary information to calculate the obtained to the expected temperature after approach, are preferably on various places sensors used in the motor vehicle to control the coupling and / or the motor vehicle transmission necessary state variables, signals and provide readings that are processed by the control unit. A signal transmission from sensor to control unit and vice versa, this can be done on one contactless Ways or over a cable or the like can be performed. The transferred Signal can in the sense of this invention an analog or a discrete or be a digital signal.

The Replacement strategy can give the control unit a permissible engine torque for approaching of the motor vehicle, so that the expected temperature is below the temperature limit. This will achieve that the maximum allowable Motor torque is limited in the approach in such a way that the expected temperature entry the specified temperature limit after does not exceed the approach of the motor vehicle. Independent of the accelerator pedal position is the energy input by the reduced Engine moment reduced in the clutch, which at the same time Fuel consumption during the approach can be lowered.

Of Further, the replacement strategy of the control unit may be an allowable engine speed to associate with starting of the motor vehicle, in which the expected Temperature is below the temperature limit. The maximal allowed Engine speed is during the upcoming approach in the way so limited that the expected Temperature does not reach or exceed the predetermined limit.

Preferably assigns the replacement strategy of the control unit a permissible engagement time for the approach of the motor vehicle to, at the expected temperature is below the temperature limit. In this alternative The clutch is closed faster.

at In a further embodiment of the invention, the replacement strategy deny access to the motor vehicle until (depending on the input variables) Expected temperature is below the temperature limit. Lies the expected temperature after arrival (for example at a certain degree of activity of the load lever) above the temperature limit, none occurs Approach of the motor vehicle. This can occur, for example, if already the clutch due to several approaches one has reached a certain temperature which is close to the temperature limit. Now occurs the user of the motor vehicle, the accelerator pedal completely (Kick down), would an energy input into the clutch during the approach process cause that the temperature of the clutch after starting above the temperature limit lies. For the user of the motor vehicle is in this embodiment the invention the possibility the accelerator pedal less far (as desired) to operate, so that the expected temperature does not reach the temperature limit.

at this embodiment However, it is advantageous that the user of the motor vehicle receives a corresponding information, if an operation of the Accelerator Pedals the vehicle does not start. This can be a visual and / or acoustic display device arranged in the interior of the motor vehicle be activated if the control unit is a temperature reached above the temperature limit. Of course it is this display device also on the other replacement strategies applicable.

The can substitute strategies mentioned independently from each other for the approach of the motor vehicle can be applied separately. A Combination of said replacement strategies is also possible, the means that several strategies are used at the same time can. In the latter case, for example, the replacement strategy the control unit a certain Einkuppelzeit and a specific Assign engine torque for approaching the motor vehicle, so that the expected temperature after approach the temperature limit does not exceed.

In a preferred alternative, the clutch on your Kupplungsreibbelägen at least one sensor that detects the temperature. The sensor is in signal communication with the control unit, so that the current temperature of the clutch friction linings can be taken into account for the calculation of the expected temperature after the approach. The current temperature of the Kupplungsreibbelages represents one of many input variables, which are included in the calculation of the expected temperature. The permissible engine torque and / or the permissible engine speed and / or the admissible engagement time are preferably determined as a function of the input variables. The input variables may include, for example, various load models, which are taken into account in the calculation of the permissible engine torque, the permissible engine speed and the engagement time. The input variables can also take into account whether many approaches have already been made within a very short time. On the basis of maps stored in the control unit, for example, a reduction of the engine speed, the engine torque and the engagement time can be such that the expected temperature of Kupplungsreibbelages is below the temperature limit. In this case, the control unit can generate an output signal which is transmitted to the clutch and / or the motor vehicle transmission and triggers the action demanded by the replacement strategy there.

Of the Amount of reduction of desired Engine speed, engagement time or the desired permissible engine torque to one allowed Size, at the expected temperature below the temperature limit is determined, for example, based on different maps become. In a preferred embodiment, for example a reduction of the desired Value to a permissible value Value be greater, The higher the expected temperature over the temperature limit. Of course, in this context a variety of other reduction options possible, the For example, based on Algorhythmen, maps, etc. deposited could be.

With Help of the method according to the invention can be high Clutch temperatures and extreme clutch wear avoided so that the clutch life can be significantly increased. Of Further can due to the method according to the invention smaller clutches are used in the motor vehicle. In wet clutch systems can also smaller, cheaper cooler be used.

The The above object is further achieved by a control unit Claim 9 and by a motor vehicle according to claim 10.

The inventive method can be recorded in a program in a computer program product be. The computer program product may preferably be to trade a computer readable recording medium. The program is hereby preferably on a magnetic recording medium recorded as a floppy disk or on an optical recording medium, like a CD-Rom, a CR-R (Compact disk recordable), a flash memory (flash memory) or similar. By using the recording medium can be the program at a plurality of control units through the recording medium install, thereby improving the applicability of the method becomes.

Further Advantages, features and details of the invention will become apparent the following description, with reference to the drawing an embodiment the invention is described in detail. The can in the claims and features mentioned in the description each individually for itself or in any combination essential to the invention.

1 shows a diagram 100 in which a sequence of a method according to the invention for controlling a clutch and / or a motor vehicle transmission is illustrated by means of blocks.

In block 101 the procedure is started. In block 102 it is checked whether an approach of the motor vehicle is intended. About sensors that are arranged on the accelerator pedal, the degree of actuation of the accelerator pedal can be detected. The sensors pass this information on to a control unit, which in block 103 a to be expected after the arrival temperature of the clutch, in particular the Kupplungsreibbeläge calculated. The expected temperature is dependent on various input variables, for example, the current temperature of Kupplungsreibbeläge, geometry of the clutch, engine torque, etc. In block 104 a check is made as to whether the temperature of the coupling to be expected after the approach reaches or exceeds a temperature limit value stored in the control unit. If the calculated final temperature of the clutch is below the temperature limit, the method according to the invention is in block 114 finished and there is a journey corresponding to the position of the accelerator pedal.

If the calculated final temperature has reached or exceeded the temperature limit after the start, the system takes place in block 105 a query as to whether the engine torque has already been reduced. If the engine torque has not been reduced during the procedure, block 106 the engine torque is reduced according to a certain amount. Then it is back in block 103 a calculation of the expected temperature after the start including the new, reduced engine torque. Is that in the query of the block 104 calculated final temperature of the clutch below the temperature limit, the inventive method in block 114 finished and there is a journey of the motor vehicle with a block 106 reduced engine torque.

If, however, the temperature to be calculated has reached or exceeded the temperature limit after start-up, block no 105 the renewed query whether the engine torque has already been reduced during the process. If the engine torque in block 106 already reduced, takes place in block 107 a query as to whether the engine speed has been reduced. If the engine speed has not yet been reduced, block 108 the engine speed is reduced by a certain amount and it takes place in block 103 in turn, a calculation of the coupling end temperature after the approach of the motor vehicle with a subsequent query in block 104 whether the temperature limit is reached or exceeded.

In block 109 a query is made whether the Einkuppeldauer (Einkuppelzeit) has already been reduced. If the query is answered with "No", in block 110 the Einkuppelzeit reduced by a certain amount and it is again a calculation of the coupling end temperature after approaching in block 103 , In block 111 a check is made as to whether the maximum number of reductions has been reached. If this maximum number has not yet been reached, block 112 a further reduction of engine torque, engine speed and Einkuppeldauer allowed. If the maximum number of reductions has been reached, the block will be used 113 a start of the motor vehicle denied until the current clutch temperature has a certain below the temperature limit value.

This method just described is performed by the control unit, which is directly or indirectly connected to the clutch and / or with the motor vehicle transmission, wherein the reduction of the engine torque in block 106 , the engine speed in block 108 , the coupling period in block 110 and the refusal of access until the current clutch temperature has a permissible value in block 113 , taken in each case represent a substitute strategy for the approach of the motor vehicle. The control unit may be further connected to other electronic units, wherein a connection, for example via a data bus, for. B. a CAN bus can be done. The electronic units may be, for example, an engine electronics or electronics of an anti-lock braking system or an anti-skid control. The sensors determine the respective values of the input variables that are necessary for the calculation of the expected temperature after the approach, such as engine speeds, the position of the driving pedal, the gear position of the transmission, the engine torque and other vehicle-specific characteristics.

The The invention is not limited to the illustrated embodiment of the description limited. It is self-evident possible, to vary the order of the respective replacement strategies. Of Further it also offers itself, only a substitute strategy or just a set number of strategies to control the Use coupling and / or the motor vehicle transmission. Further is a simultaneous combination of the replacement strategies described possible, this means that z. B. at the same time the Einkuppeldauer and the Engine torque can be reduced, to get a temperature after the approach of the motor vehicle, which is below the temperature limit.

Claims (11)

Method for controlling a with a control unit directly or indirectly connected clutch and / or a motor vehicle transmission, wherein the control unit before each approach of the motor vehicle a calculated after the expected temperature of the clutch and compared with a temperature limit, wherein the control unit a replacement strategy for the approach of the motor vehicle chooses, if the expected Temperature reaches or exceeds the temperature limit, wherein for the approach of the motor vehicle, the replacement strategy of the control unit a permissible one Assigns engine torque and / or the replacement strategy of the control unit a permissible one Assigns engine speed and / or the replacement strategy of the control unit a permissible one Coupling time assigns, so that the expected temperature below of the temperature limit, and / or the replacement strategy Approach of the motor vehicle as long denied until the expected temperature is below the temperature limit. Method according to claim 1, characterized in that that the motor vehicle transmission is a manual transmission or an automatic transmission is. Method according to claim 1 or 2, characterized that the control unit is in signal communication with sensors. Method according to claim 3, characterized the coupling has clutch friction linings on which at least a sensor detects the temperature. Method according to one of the claims, characterized in that at least one sensor is arranged on a load lever is the degree of actuation of the load lever detected. Method according to one of the claims, characterized characterized in that the control unit is connected to electronic units is. Method according to Claim 6, characterized that the control unit over a data bus is connected to the electronics unit. Method according to one of the claims, characterized in that a visual and / or acoustic display device is arranged in the interior of the motor vehicle, which is activated, if the control unit chooses a replacement strategy. Control unit designed such that the method according to one or more of the preceding claims in the Control unit is executable. Motor vehicle comprising a control unit and / or a method according to any one of the preceding claims. Computer program product for executing the Method according to one or more of the preceding claims, characterized characterized in that the method is in one in the computer program product stored program is integrated.