Method and device for controlling and adjusting a clutch in an automotive automatic stepped power shift gearbox

• US 6,708,097 B1
• Filed: 03/28/2002
• Issued: 03/16/2004
• Est. Priority Date: 10/30/1999
• Status: Expired due to Fees

• Current Assignee: ZF Friedrichshafen AG (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Original Assignee: ZF Friedrichshafen AG (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Inventors: Vohmann, Martin, Dreibholz, Ralf
• Primary Examiner(s): Cuchlinski, Jr., William A.
• Assistant Examiner(s): Hernandez, Olga
• Application Number:
  US10/089,375
• Time in Patent Office: 719 Days
• Field of Search: 701/68, 701/67, 701/78, 180/170, 180/174, 180/175, 180/176, 180/177, 180/179
• US Class Current: 701/68
• CPC Class Codes: B60W 2710/027 Clutch torque
• CPC Class Codes: F16D 2500/5048 Stall prevention
• CPC Class Codes: F16D 48/06 Control by electric or electronic means, e.g. of fluid pressure
• CPC Class Codes: F16H 2312/02 Driving off
• CPC Class Codes: F16H 61/061 using electric control means

Abstract

A process for controlling and regulating a clutch in a stepped load switchable automatic transmission for a motor vehicle where an electronic control device determines the behavior of the clutch during three operating conditions by way of a first or a second control circuit, and that a shift from a first into a second gear ratio stage takes place. In accordance with the invention, the first control circuit is used for controlling and regulating the clutch during the first operating condition, whose controlled variable is equivalent to the actual value of the engine speed (n_MOT_IST). During the second driving condition, a second control circuit is used, whose controlled variable is equivalent to the actual value of a differential rotational speed (dnK_IST) of the clutch, and during the third operating condition, the clutch is impinged with a controlled pressure value dependent upon various influence magnitudes.

Claims

1. A process for controlling and regulating a clutch in a stepped power shiftable automatic transmission for a motor vehicle in which an electronic control device determines the behavior of the clutch during operating conditions in which a load shift from a first gear ratio step to a second gear ratio step can be effected, the process comprising the steps of:

in a first operating condition where the vehicle is under acceleration and below a first vehicular limiting speed, controlling the clutch by a control device, a first control circuit having a first control parameter input equivalent to an actual value of engine speed,

in a second operating condition where the vehicle is over the first vehicular limiting speed, controlling the clutch by a control device, a second control circuit having a second control parameter input equivalent to an actual value of a differential rotational speed and where the actual value of the differential rotational speed is not reset to zero, and

in a third operating condition where the vehicle is in overrun and below a second vehicle limiting speed, controlling the clutch by a control pressure dependent on various parameters,

wherein the load switching is decisively determined by a third control circuit and the first and third or the second and third control circuits are connected with one another via a decoupling network, wherein the decoupling network has in each case a first and a second signal value.

2. The process according to claim 1, wherein with a load switching from the first (i1) into the second gear ratio step (i2) of the automatic transmission, during the first operating condition, the first control circuit acts upon the third control circuit by means of the decoupling network via a first signal path, and the third control circuit acts upon the first control circuit by means of the decoupling network via the second signal pathway.

3. The process according to claim 1, wherein in connection with a load switch from the first (i1) into the second gear ratio step (i2) of the automatic transmission, during the second operating condition, the second control circuit acts upon the third control circuit by means of the decoupling network, and the third control circuit acts upon the second control circuit by means of the decoupling network via a second signal pathway.

4. A process for controlling and regulating a clutch in a stepped power shiftable automatic transmission for a motor vehicle, in which an electronic control device determines the behavior of the clutch during operating conditions in which a load shift from a first gear ratio step to a second gear ratio step can be effected, the process comprising the steps of:

in a first operating condition where the vehicle is under acceleration and below a first vehicular limiting speed, controlling the clutch by a control device, a first control circuit having a first control parameter input equivalent to an actual value of engine speed,

in a second operating condition where the vehicle is over the first vehicular limiting speed, controlling the clutch by a control device, a second control circuit having a second control parameter input equivalent to an actual value of a differential rotational speed and where the actual value of the differential rotational speed is not reset to zero, and

in a third operating condition where the vehicle is in overrun and below a second vehicle limiting speed, controlling the clutch by a control pressure dependent on various parameters;

a control pressure level (pAK) of the clutch in the first and second condition results from an offset value (pAK_OFF) and a summation value (pSUM)(pAK=pAK_OFF+pSUM), wherein the summation value (pSUM) is decisively determined on the basis of the balance of a controlled torque (MK(ST)) of the clutch, a regulated summation torque (MK(RE)′

) of the clutch, and a decoupling load switching torque (MLS_ENT)(pSUM=f(MK(ST), MK(RE)′

, MLS_ENT)).

5. The process according to claim 4, wherein the controlled torque (MK(ST)) is decisively determined on the basis of a clutch dynamic torque (MDYN_K) and an engine torque (MMOT)(MK(ST)=f(MDYN_K, MMOT).

6. The process according to claim 4, wherein the regulated summation torque (MK(RE)′

) of the clutch is determined on the basis of a dynamic engine torque (MDYN_MOT) and a regulated torque (MK(RE)) of the clutch.

7. The process according to claim 6, wherein the regulated summation torque (MK(RE)) in the first driving condition is decisively determined on a basis of a theoretical/actual comparison of a magnitude equivalent to the engine speed and a performance specification (DKI) of a driver by means of a regulator.

10. The process according to claim 6, wherein the regulated torque (MK(RE)) is definitively determined on a basis of a theoretical/actual comparison of the rotational speed differential (dnK_SW, dnK_IST) of the clutch and a performance specification (DKI) of a driver by means of a regulator.

11. The process according to claim 10, wherein the regulator contains a restricted integrator, wherein the integrator is fed, as input magnitudes, a system deviation from the theoretical/actual comparison of the rotational speed differential (dnK_SW, dnK_IST) of the clutch, an adjustment speed of the performance specification (DKI), and a ratio of the actual to the theoretical value of the differential rotational speed (dnK_IST/dnK_SW) of the clutch.

12. The process according to claim 10, wherein the theoretical value of the differential rotational speed (dnK_SW) of the clutch results from an addition of a theoretical value offset (dnLS_SW) and a gear-dependent differential rotational speed (dn_SW(i)) of the clutch.

13. The process according to claim 12, wherein during a transition from the first or third operating condition, in the second operating condition, the theoretical value of the differential rotational speed (dnK_SW) is guided over a dynamic delaying element, wherein the current actual value of the differential rotational speed (dnK_IST) is set as an initial value of the theoretical value of the differential rotational speed.

14. The process according to claim 12, wherein in the second operating condition, the theoretical value offset of the differential rotational speed (dnLS_SW) of the clutch during load switching from a first (i1) into a second gear ratio step (i2) of the automatic transmission is increased in a load assumption or gradient adjusting phase and is reduced again with a termination of a concluding phase.

15. The process according to claim 12, wherein a gear-dependent theoretical rotational speed (N_MOT_SW(i)) for a startup gear of the automatic transmission is determined by characteristics maps (KF(i)) wherein the characteristics maps represent an allocation of performance specifications (DKI) by a driver and an output rotational speed (nAB) of the clutch and wherein the transfer from a first characteristics map (KF(i1)) to a second characteristics map (KR(i2)) during the load switch takes place at the end of a gradient adjustment phase.

8. A process for controlling and regulating a clutch in a stepped power shiftable automatic transmission for a motor vehicle, in which an electronic control device determines the behavior of the clutch during operating conditions in which a load shift from a first gear ratio step to a second gear ratio step can be effected, the process comprising the steps of:

in a first operating condition where the vehicle is under acceleration and below a first vehicular limiting speed, controlling the clutch by a control device, a first control circuit having a first control parameter input equivalent to an actual value of engine speed,

in a second operating condition where the vehicle is over the first vehicular 4 limiting speed, controlling the clutch by a control device, a second control circuit having a second control parameter input equivalent to an actual value of a differential rotational speed and where the actual value of the differential rotational speed is not reset to zero, and

in a third operating condition where the vehicle is in overrun and below a second vehicle limiting speed, controlling the clutch by a control pressure dependent on various parameters;

a gear-dependent theoretical rotational speed (N_MOT_SW(i)) for a startup gear of the automatic transmission is determined by characteristics maps (KF(i)), wherein the characteristics maps represent an allocation of performance specifications by a driver (DKI) and an output rotational speed (nAB) of the clutch.

9. The process according to claim 8, wherein a switch from a first characteristics map (KF1(i1)) to a second characteristics map (KF1(i2)) during a load switch takes place at the end of a gradient adjustment phase.

16. A process for controlling and regulating a clutch in a stepped power shiftable automatic transmission for a motor vehicle, in which an electronic control device determines the behavior of the clutch during operating conditions in which a load shift from a first gear ratio step to a second gear ratio step can be effected, the process comprising the steps of:

in a first operating condition where the vehicle is under acceleration and below a first vehicular limiting speed, controlling the clutch by a control device, a first control circuit having a first control parameter input equivalent to an actual value of engine speed,

in a second operating condition where the vehicle is over the first vehicular limiting speed, controlling the clutch by a control device, a second control circuit having a second control parameter input equivalent to an actual value of a differential rotational speed and where the actual value of the differential rotational speed is not reset to zero, and

in a third operating condition where the vehicle is in overrun and below a second vehicle limiting speed, controlling the clutch by a control pressure dependent on various parameters;

at a vehicular speed (v) of less than a limiting value (GW), an increased differential rotational speed (dn_SW(i)) of the clutch is set as stalling protection over a respective characteristics map (KF(i)).

17. The process according to claim 16, wherein the differential rotational speed (dn_SW(i)) is set to be greater than the difference on the basis of the most minimal rotational speed of an internal combustion engine (n_MOT_MIN) and an output rotational speed of the clutch (nAB).

18. A control device for controlling and regulating a clutch in a stepped power shiftable automatic transmission for a motor vehicle in which the control device determines the behavior of the clutch in operating conditions in which a load shift from a first gear ratio step to a second gear ratio step can be effected, comprising:

a first control circuit having a first control parameter input equivalent to an actual value of engine speed for controlling the clutch in a first operating condition wherein the vehicle is under acceleration and below a first vehicular limiting speed, controlling the clutch by a control device,

a second control circuit having a second control parameter input equivalent to an actual value of a differential rotational speed for controlling the clutch in a second operating condition wherein the vehicle is over the first vehicular limiting speed, wherein the actual value of the differential rotational speed is not reset to zero, and

a third control circuit for definitively detecting a load shift connected via a decoupling network to the first and second control circuit,

a decoupling network providing a first signal path between the first and third control circuits and a second signal path between the second and third control circuits, and

the clutch is controlled by a control pressure dependent on various parameters in a third operating condition wherein the vehicle is in overrun and below a second vehicle limiting speed.