Load reducing method for automatic transmissions during limp home shifting operations
AssigneeZF Friedrichshafen AG
InventorHagen Lukas
Life of this patent
Estimating the term…
Abstract
Within the scope of a load reduction method of automatic transmissions or clutches of a motor vehicle during emergency program shifting operations, an engine torque reduction is carried out during the emergency program shifting operation from a normal shifting program to an emergency program (NP).
Claims11
A method for reducing a clutch load in an automatic transmission of a motor vehicle during an emergency program shifting operation when an electronic transmission control of the automatic transmission is not operative, the method comprising the steps of:
- detecting the inoperative electronic transmission control as an erroneous operating condition in the automatic transmission;
- reducing an engine torque by operation of an engine control unit (ECU) during the emergency program shifting operation;
- and
- shifting the automatic transmission from a normal shifting program to an emergency program (NP) and continuing to operate the motor vehicle in the emergency program (NP) without the electronic transmission control.
A method for reducing a clutch load in an automatic transmission of a motor vehicle for continued operation of the motor vehicle in an emergency running program (NP), the method comprising the steps of:
- detecting a failure of an electronic transmission control and activating an emergency shifting program;
- determining a time period and intensity of an engine engagement as a function of current engine and transmission operating parameters;
- reducing an engine torque according to the time period and intensity of the engine engagement solely via operation of the engine control unit (ECU) to significantly reduce the clutch load in the automatic transmission;
- and
- continuing operation of the motor vehicle by shifting from a normal vehicle running program to an emergency vehicle running program (NP).
Dependencies are inferred from the claim text.