System and method for controlling vehicle creep torque
AssigneeGM Global Technology Operations LLC
InventorPatrick J. Monsere
Life of this patent
Estimating the term…
Abstract
A system and method for controlling creep torque in a vehicle with an electric powertrain, like a hybrid electric vehicle (HEV). The method uses a combination of driver braking intent and other vehicle conditions, such as vehicle speed, to determine when creep torque is not needed and to reduce and/or cancel it accordingly. By reducing and/or cancelling the creep torque during periods where energy is being unnecessarily expended by the electric powertrain in order to work against the brakes, the present method is able to improve the overall efficiency of the vehicle.
Claims15
A method for controlling creep torque in a vehicle with an electric powertrain, comprising the steps of:
- a) gathering brake signals from a brake sensor and speed signals from one or more speed sensor(s);
- b) using the brake signals to compare a requested brake torque to a minimum brake threshold and using the speed signals to compare a current vehicle speed to a maximum speed threshold, wherein the current vehicle speed must be less than or equal to the maximum speed threshold for a certain amount of time in order to determine when the creep torque should be reduced;
- c) when it is determined that the creep torque should be reduced, then reducing the creep torque;
- d) continuing to monitor the brake signals from the brake sensor and using the brake signals to compare another requested brake torque to a reinstatement threshold to determine when the creep torque should be reinstated;
- and
- e) reinstating the creep torque when the requested brake torque is less than or equal to the reinstatement threshold.
A method for controlling creep torque in a vehicle with an electric powertrain, comprising the steps of:
- a) gathering one or more vehicle condition(s);
- b) using the vehicle condition(s) to determine when the creep torque should be reduced;
- and
- c) when it is determined that the creep torque should be reduced, then artificially manipulating a requested brake torque from the driver so that a manipulated brake torque satisfies a predetermined threshold that causes a reduction of the creep torque, even though the actual requested brake torque does not satisfy the predetermined threshold.
A system for controlling creep torque in a vehicle with an electric powertrain, comprising:
- a brake sensor providing brake signals;
- one or more speed sensor(s) providing speed signals;
- and
- a control unit coupled to the brake sensor and the speed sensor(s), wherein the control unit is configured to gather vehicle conditions including the brake signals and the speed signals, to use the vehicle conditions to determine when the creep torque should be reduced, and when it is determined that the creep torque should be reduced, to artificially manipulate a requested brake torque from the driver so that a manipulated brake torque satisfies a predetermined threshold that causes a reduction of the creep torque, even though the actual requested brake torque does not satisfy the predetermined threshold.
Dependencies are inferred from the claim text.