METHOD FOR CONTROLLING AN AUTOMATIC TRANSMISSION OF A MOTOR VEHICLE

• US 20100204007A1
• Filed: 07/03/2008
• Published: 08/12/2010
• Est. Priority Date: 07/27/2007
• Status: Active Grant

• Current Assignee: ZF Friedrichshafen AG (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Original Assignee: ZF Friedrichshafen AG (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Inventors: Winkel, Matthias, Kneer, Reiner, Mair, Roland, Jager, Thomas
• Granted Patent: US 8,512,205 B2
• Time in Patent Office: Days
• US Class Current: 477/34
• CPC Class Codes: B60W 10/10 including control of change-speed gearings
• CPC Class Codes: B60W 10/196 acting within the driveline, e.g. retarders
• CPC Class Codes: F16H 2061/023 Drive-off gear selection, i.e. optimising gear ratio for drive off of a vehicle
• CPC Class Codes: F16H 2061/163 Holding the gear for delaying gear shifts under unfavorable conditions, e.g. during cornering
• CPC Class Codes: F16H 61/16 Inhibiting or initiating shift during unfavourable conditions, e.g. preventing forward reverse shift at high vehicle speed, preventing engine over speed unintentional control input F16H61/18

Abstract

A method of controlling an automatic transmission of a vehicle in which a hold gear function is activated by a driver request and is deactivated independently of a return condition. To allow an effective, safe to operate, and comfortable use, the return condition depends on one of the following criteria or a useful combination of the same: a flexible time span, consideration of the vehicle stand still time; a rotational speed of the vehicle engine, or one or several parameters which correlate with the engine rotational speed, a new, the same, or a different drive request by the driver, a change in the operating condition of the vehicle, and a plausibility check occurring during the startup procedure.

Claims

1-25. -25. (canceled)

26. A method of controlling an automatic transmission of a vehicle, in which a hold gear function is activated by a request from a driver and deactivated independently of a return condition, the method comprising the steps of:

determining the return condition by at least one of;

a flexible time span which depends on a stand still time of the vehicle;

either a rotational speed of an engine of the vehicle or at least one parameter correlated with the rotational speed of the engine;

one of a new drive request, a same drive request, or a different drive request by the driver;

a change in operating condition of the vehicle; and

a plausibility check under consideration of a startup procedure.

27. The method according to claim 26, further comprising the step of starting a timer upon activation of the hold gear function and terminating the hold gear function after the expiration of the flexible time span, and the timer is stopped during each stand still of the vehicle.

28. The method according to claim 27, further comprising the step of resetting the timer to zero at each stand still of the vehicle.

29. The method according to claim 26, further comprising the step of deactivating the hold gear function if a renewed driver request for the hold gear function is registered.

30. The method according to claim 26, further comprising the step of extending the time span for the hold gear function if a renewed request from the driver for a hold gear function is registered.

31. The method according to claim 30, further comprising the step of resetting the timer upon the renewed request from the driver for the hold gear function.

32. The method according to claim 30, further comprising the step of increasing the time span of the timer by a predetermined increment upon the renewed request from the driver for the hold gear function.

33. The method according to claim 26, further comprising the step of deactivating the hold gear function, during a start up operation, if the plausibility check determines a currently engaged gear, by a request of the driver, is not suitable for a start up operation.

34. The method according to claim 26, further comprising the step of prioritizing a currently engaged gear as requested by the driver, during a start up operation, if the plausibility check determines that the currently engaged gear is suitable for a start up operation.

35. The method according to claim 26, further comprising the step of limiting a range of automatically shifted gears, during a start up operation, by a top gear at which the hold gear function had been activated.

36. A method of controlling an automatic transmission of a vehicle in which a hold gear function is activated by a request of a driver and, dependent on a return condition, being deactivated, whereby the return condition is one of determined depending on a rotational speed of the engine of the vehicle and at least one parameter which correlates with the rotational speed of the engine, the method comprising the step of:

deactivating the hold gear function if, under consideration of the request of the driver, the rotational speed or the at least one parameter either exceeds or falls below a prior determined upper or lower threshold value.

37. The method according to claim 36, further comprising the step of defining the threshold value as one of the rotational speed of the engine and a transmission input rotational speed.

38. The method according to claim 36, further comprising the step of deriving the threshold value from one of a transmission output rotational speed and a related transmission ratio of an engaged gear, or a vehicle speed and at least one of a related transmission, wheel, and axle drive ratio conversion factor.

39. The method according to claim 36, further comprising the step of interpreting at least one of an activated drive pedal, an activated brake pedal and an activated secondary brake system as the relevant threshold driver request.

40. A method of controlling an automatic transmission of a vehicle, in which a hold gear function is activated by a driver request, and deactivated depending on a return condition, the method comprising the step of:

determining the return condition by one of a new driver request and a different driver request, and deactivating the hold gear function, if the registered driver request is one of accompanied with a change of driving direction and leads to activation of a kick down switch.

41. A method of controlling an automatic transmission of a vehicle, in which a hold gear function is activated by a driver request and deactivated depending on a return condition, the method comprising the step of:

determining the return condition by a change in operating state, and deactivating the hold gear function, if a temporary operating state for which the hold function is being requested, ends and a change takes place between one of uphill driving and downhill driving and between driving one of up and down a hill and driving on a same plane.