DE19549081A1 - System for controlling coupling arranged between vehicle engine and wheels - Google Patents

Abstract

The control system includes a converter bypass coupling (17) arranged between a vehicle engine (10) producing an engine torque (Mmot) and the wheels (13) of a vehicle. The coupling with a control signal (PWK) can at least reduce the power flow between the engine and the wheels. The control signal is formed depending on a signal (DELTA Mmot), which represents a value determining the engine torque. A hydromechanical torque converter (11) is arranged between the engine and a gearbox (12). A bypass or bridging coupling (17) is arranged between the engine and the vehicle wheels. The retardation is carried out depending on a status signal (St), representing the instantaneous operating condition of the coupling. The torque converter (11) can be bridged by the coupling (17), which can be a servo coupling.

Description

State of the art

The invention relates to systems for controlling a clutch and / or a vehicle engine according to the preamble of Claims 1 and 2.

Automatic clutches or servo clutches are for example, known from "automotive engineering Paperback, edition, 1991, pages 538 and 539 or the DE application P 19540921. Servo clutches offer in connection with electronic control units either one automated starting process or, together with servo-operated manual transmissions, a fully automatic Transmission. With such servo couplings the opening and Closing the clutch generally by a Servo drive activated.

In addition to such servo clutches are automatic transmissions known in which the control signal Gear ratios are changeable. Such Automatic transmissions can be made in a known manner hydraulic converter to be connected to the vehicle engine.  

It is known that when changing the Gear ratio resulting shift shock or the this may result Powertrain vibrations weakened by the converter can be. The converter can be a known Converter lockup clutch can be bridged or it can the bridging can be removed. Here is this Converter lockup clutch at higher Vehicle speeds or in the upper gears mostly closed. So that the slip losses of the Torque converter prevents what the Reduced fuel consumption drivetrain vibration damping effect of the converter but not given with the clutch closed. About that it can also be provided that the slip of such Converter clutches is regulated.

It is also known to control a Motor vehicle engine to provide an engine control unit, by means of depending, for example, on the driver's wish, on engine loading drive parameters and other, the operation of the vehicle influencing or representing variables Motor output torque is controlled. Describes this for example, DE-OS 43 21 333 an electronic Accelerator pedal system, in which measures to reduce Powertrain vibrations during the transition from the thrust to the Train phase are provided. These are that the Transition from the overrun to the pull phase is recognized and at a recognized transition the execution of the driver's request to adjust the power of the internal combustion engine is delayed.

The object of the present invention is to develop such systems to optimize drive train vibration.  

This object is achieved by the features of claims 1 and 2 solved.

Advantages of the invention

In a first embodiment, the invention is based on one System for controlling a clutch made between a an engine torque generating vehicle engine and the wheels a vehicle is arranged. Through this clutch can in response to a control signal, the flow of force between the Vehicle engine and the wheels changed, for example. At least be reduced, or the rigid coupling between the Vehicle engine and the wheels are lifted. The core of the The first variant of the invention is that Control signal of the clutch depending on a signal is formed that determined a change in engine torque Represented extent. These first according to the invention Variant has the advantage that opening or regulating the Converter clutch before a significant change in the Motor output torque is effected. This allows the The converter must remain closed even in the lower gears not, quasi-prophylactically because of the circumstances occurring drive train vibrations, for reasons of comfort be opened or regulated. This leads to minimal Energy losses that are incomplete at one closed converter clutch occur without the comfort too reduce.

In this variant it can be provided that the one Change in engine torque signal representing one of the engine control to be initiated, in particular erratic, Represented change in engine torque.

The engine torque is generally determined using a Motor control the clutch by means of a clutch or  Transmission control controlled or regulated. Then it can provided that this is a change in engine torque representative signal formed in the engine control and the clutch or transmission control is supplied.

In response to one represented by the signal changes to be initiated, in particular sudden changes Motor torque, the control signal can be formed in such a way that the rigid coupling between the vehicle engine and the Wheels is lifted. During this coupling closed converter clutch is rigid, this can be rigid Coupling through an open converter clutch (with or without Slip) can be eliminated.

The invention goes in the second variant according to the invention from a system for controlling a vehicle engine an actuator for influencing the engine torque, which at least depending on the recorded driver request is set. If there is a change in Desired engine torque of a certain extent takes place Execution of the request (e.g. driver request and / or Cruise control / vehicle speed control) for setting the Engine torque delayed. The essence of the invention second variant is that between the Vehicle engine and the wheels of the vehicle have a clutch is arranged and the delay depending on the representing the current operating state of the clutch Status signal is made. This second according to the invention Variant has the advantage that the to reduce the Drivetrain vibrations provided deceleration of the Desired moment is only made when the Converter clutch the aforementioned does not suppress drive train vibration damping can run because it is closed or insufficient is open.  

In this variant, it is advantageously provided that the status signal mentioned the presence of at least one of three operating states. The first operating state is through an open clutch, the second Operating state through a closed clutch and the third operating state by a regulated Coupling operation marked.

The engine torque is generally determined using a Engine control and the clutch by means of a clutch or Transmission control controlled or regulated. It is it is advantageous that the status signal of the clutch in the Clutch or transmission control formed and the Motor control is fed. In response to that through the Status signal represented first or third Operating state of the clutch (clutch not complete closed) can delay the execution of the Driver request to adjust the engine torque not at all or just modified to reduce the Delay.

In both variants, the Motor torque change to a certain extent

• - a change of sign of the engine torque,
• - an interruption or abrupt reduction in Engine fueling (e.g. in response to a recognized overrun operation of the engine) and / or
• - a restart after an interruption or a Reduction of the fuel supply to the engine or one sudden increase in the fuel supply to the engine (e.g. after or to end the overrun operation)

act.  

As already mentioned it can be provided that by means of the Coupling a torque converter is bridged, or that the Clutch is a servo clutch.

Further advantageous configurations are the See subclaims.

drawing

Figs. 1 and 2 show schematic block diagrams of the embodiments for both embodiments of the invention.

Embodiment

The invention is to be clarified on the basis of the exemplary embodiments described below. Here, in Figs. 1 and 2 provided the same effect elements with the same reference numerals.

In Figs. 1 and 2, between a vehicle engine 10 and a transmission 12 arranged torque converter is denoted by reference numeral 11 to which the output torque M _mot of the motor 10 is supplied by means of a drive shaft. The converter 11 is connected on the output side to the wheels 13 via the transmission 12 , the transmission being an automatic transmission 12 in this exemplary embodiment. The operation of the vehicle engine 10 is controlled or regulated by the engine control unit 101 , the driving desire of the driver being essentially assumed. For this purpose, the position of an accelerator pedal 1 which can be actuated by the driver is fed to the engine control 101 in FIG. 2.

The hydromechanical converter 11 can be bridged by the clutch 17 , wherein the clutch can be opened or closed completely or partially by the control signal P _WK . The clutch or transmission control unit 16 controls or regulates the clutch 17 in addition to the transmission ratio i of the transmission 12 . To this end, the clutch or transmission control unit 16 is supplied in particular with the engine speed N _mot detected by the sensor 14 and the turbine or converter output speed N _T detected with the sensor 15 . To determine the gear ratio i, the engine load or the driver's desire for propulsion and the vehicle speed are generally used (not shown).

As mentioned, the converter lock-up clutch can be closed or opened, but in addition a regulation of the clutch slip, which is derived, for example, from the ratio of N _mot to N _T, can also be provided. Most automatic transmissions 12 today have such a lockup clutch 17 , which is generally closed in the higher gears in order to minimize the increased fuel consumption caused by the converter slip. The disadvantage of this bridging is, however, that the bridging also eliminates the pressure-damping or drive train vibration damping effect of the transducer 11 . Rapid changes in the engine torque M _mot can then, under certain circumstances, be passed on to the drive train of the vehicle almost undamped, which means that the vehicle tends to jerk. This jerking is particularly noticeable when two engine operating conditions are present:

• 1. During the transition from normal operation (fired operation with normal fuel metering) to the known overrun cutoff (shutdown of the fuel supply when the engine is in overrun mode) and vice versa when the fuel supply is restarted after such overrun cutoff. In these phases, the engine torque M _mot increases suddenly.
• 2. When changing the sign of the engine torque M _mot (transition from pushing to pulling the engine), because here the tooth flanks in the drive train change their system.

In both operating conditions, there is a marked change in the engine torque. Since these changes are initiated by the engine control unit 101 , these changes are also predictable, as it were, with foresight.

As mentioned, the converter clutch 17 can also be operated in a controlled manner, which means that the clutch is neither fully closed nor fully open in this control state. The clutch pressure is adjusted so that the clutch grinds with a slight slip. The advantage here is that the energy losses in the converter are significantly lower than with an open clutch, but the damping effect of the converter is at least partially effective. The disadvantage here, however, is that a certain additional fuel consumption is inevitable compared to the completely closed clutch.

Essential for the first embodiment of the invention ( FIG. 1) is the signal .DELTA.M _mot , which is supplied to the clutch or transmission control unit 16 by the engine control 101 . This signal ΔM _mot indicates whether the engine controller 101 controls or regulates the engine 10 in such a way that a significant change in the engine torque M _mot can be expected. In response to a _mot by the signal .DELTA.M reported marked change of the engine torque M _mot (for example, as defined by said two operating conditions), the clutch 17 is at least partly, but at best completely opened. If the engine control 101 thus wants to carry out a fuel cut-off, a restart operation after a fuel cut-off or a significant change of sign of the engine torque M _{mot is} imminent, the engine control 101 sends the clutch control 16 information ΔM _mot , on the basis of which the clutch control 16 converts the converter clutch 17 from closed to switches the regulated or open state (or from the regulated to the open state). If the action "fuel cut-off", "reinsert" or "change of engine torque" is then actually carried out, the converter clutch is then no longer closed, so that the torque jump that occurs in the drive train is damped by the converter 11 .

At this point it should be noted that instead of the Converter lock-up clutch of course also one known servo coupling can be used. In in this case the closed servo coupling would Damping of the rucksack a little bit (less Clutch slip) open.

Essential for the second embodiment of the invention ( FIG. 2) is the status signal St, which is passed from the clutch or transmission control unit 16 to the engine control unit 101 and indicates the operating state (closed, opened, partially open) of the converter lock-up clutch 17 . In the engine control unit 101 , a drive train damping is provided, by means of which the propulsion request expressed by actuating the accelerator pedal 1 is not immediately passed on to the power control (for example, throttle valve). The problem with regard to drive train vibrations, for example in response to a change in the sign of the engine torque, can be solved in a known manner (see DE-OS 43 21 333 mentioned at the outset) by means of a so-called EGAS system by a slow, i.e. delayed, passage through the sign change area, decoupled from the driver's specification be solved. If this function in the engine control unit 101 is always active, i.e. without differentiating whether the converter clutch 17 is closed, regulated or open, then in the case of the open or partially open, regulated clutch, there is double damping via the converter and the special described above EGAS function. Under certain circumstances, this can result in a relatively sluggish response behavior of the vehicle to accelerator pedal movements.

According to the second embodiment of the invention, the status is transmitted to the engine controller 101 , e.g. B. in the form of a three-stage signal St (clutch open, clutch regulated, clutch closed). The described “powertrain damping” function in engine control unit 101 is only activated when the “clutch closed” state is present. It is only steamed once:

• - About the function "powertrain damping" in engine control unit 101 with closed converter lockup clutch 17 and
• - Via the converter 11 with the converter lockup clutch 17 fully or partially open.

Regardless of the condition of the converter clutch, the Driver always has a similar response to his Accelerator pedal operations.

Instead of completely switching off the "powertrain damping" function in engine control unit 101 when the clutch is open or regulated, it can of course still remain active, but with different (weaker) parameters (less delay in the driver's request) than when the clutch is closed.

Claims (11)

1. System for controlling a between an engine torque (M _mot) generating vehicle engine (10) and the wheels (13) of a vehicle arranged coupling (17) by means of a drive signal (P _WK) out of the force flow between the vehicle engine (10 ) and the wheels ( 13 ) can at least be reduced, characterized in that the control signal (P _WK ) is formed as a function of a signal (ΔM _mot ) which represents a change in the engine torque (M _mot ) of a certain extent. 2. System for controlling a vehicle engine ( 10 ) with an actuator for influencing the engine torque (M _mot ), which is set at least as a function of the desired torque detected by means ( 1 ), the execution of the request being given when there is a change in the desired engine torque of a certain extent for setting the engine torque is delayed, characterized in that a clutch ( 17 ) is arranged between the vehicle engine ( 10 ) and the wheels ( 13 ) of the vehicle and the deceleration is dependent on a status signal (St.) representing the current operating state of the clutch ( 17 ) ) is done. 3. System according to claim 1, characterized in that the signal (ΔM _mot ) represents a change in the engine torque (M _mot ) to be initiated by the engine control ( 101 ), in particular a sudden change. 4. System according to claim 2, characterized in that the Status signal (St) the presence of at least one of three Indicates operating states, the first operating state through an open clutch, the second operating state through a closed clutch and the third Operating state through regulated clutch operation is marked. 5. System according to claim 1, characterized in that the engine torque (M _mot ) is controlled or regulated by means of a motor control ( 101 ) and the clutch ( 17 ) is controlled or regulated by means of a clutch or transmission control ( 16 ) and the signal (ΔM _mot ) is formed in the engine control ( 101 ) and the clutch or transmission control ( 16 ) is supplied. 6. System according to claim 4, characterized in that the engine torque (M _mot ) is controlled or regulated by means of a motor control ( 101 ) and the clutch ( 17 ) is controlled or regulated by means of a clutch or transmission control ( 16 ) and the status signal (St) is formed in the clutch or transmission control ( 16 ) and is fed to the engine control ( 101 ). 7. System according to claim 3, characterized in that in response to a represented by the signal (ΔM _mot ) to be initiated, in particular sudden, change in engine torque (M _mot ), the control signal (P _WK ) is formed such that the power flow changes in such a way is that the rigid coupling between the vehicle engine ( 10 ) and the wheels ( 13 ) is released. 8. System according to claim 4, characterized in that in Response to that represented by the status signal (St) first or third operating state of the clutch Delay not or modified in the sense of a Reducing the delay. 9. System according to claim 1, characterized in that the signal (ΔM _mot ) at least indicates whether

• - a change of sign of the engine torque (M _mot ),
• - An interruption or sudden reduction in the fuel supply to the engine ( 10 ) and / or
• - a restart after an interruption or a reduction in the fuel supply to the engine ( 10 ) or a sudden increase in the fuel supply to the engine ( 10 )

is provided. 10. System according to claim 1 or 4, characterized in that a torque converter ( 11 ) can be bridged by means of the clutch ( 17 ) or the clutch ( 17 ) is a servo clutch.