Motor-assist shift control in a hybrid vehicle transmission
AssigneeGM Global Technology Operations LLC
InventorsMin-Joong Kim, Shawn H. Swales
Life of this patent
Estimating the term…
Abstract
A method for operating a motor vehicle hybrid powertrain having an engine, a motor-generator and a multi-speed automatically-shiftable transmission, wherein the engine and the motor-generator operate to supply torque to the transmission for driving a vehicle. The method includes modulating the torque supply from the motor-generator to the transmission during a gear shift to minimize a transmission output torque disturbance.
Claims18
A method for operating a motor vehicle hybrid powertrain having an engine, a motor-generator and a multi-speed automatically-shiftable transmission, and for reducing an output torque disturbance in the transmission during a gear shift, the engine and the motor-generator each operatively connected to the transmission to provide a supply of torque for driving a vehicle, the method comprising:
- modulating the supply of torque from the motor-generator to the transmission during the gear shift, sufficiently such that the output torque disturbance during the gear shift is minimized;
- initiating the gear shift from an off-going gear into an on-coming gear via an off-going clutch and an on-coming clutch;
- determining a desired transmission input speed corresponding to transmission output speed, and a magnitude of output torque in the on-coming gear;
- commencing engagement of the on-coming clutch;
- determining a magnitude of torque transmitted by the on-coming clutch;
- continuing the engagement of the on-coming clutch to achieve the determined magnitude of output torque in the on-coming gear;
- determining whether a magnitude of torque transmitted by the off-going clutch is below a predetermined torque threshold;
- releasing the off-going clutch if the off-going clutch torque is below the predetermined torque threshold;
- determining whether a slip speed of the on-coming clutch is below a predetermined slip speed threshold value;
- and
- completing the engagement of the on-coming clutch to achieve the desired transmission input speed and the determined magnitude of output torque in the on-coming gear if the slip speed of the on-coming clutch is below the predetermined slip speed threshold value.
A method for controlling a power-off down-shift in a multi-speed automatically-shiftable transmission employed in a hybrid motor vehicle, and reducing an output torque disturbance in the transmission during the down-shift, the vehicle having an engine capable of being turned on and shut off and a motor-generator, the engine and the motor-generator each operatively connected to supply torque to the transmission for driving the vehicle, the method comprising:
- initiating the transmission power-off down-shift from an off-going gear to an on-coming gear via an off-going clutch and an on-coming clutch;
- regenerating braking energy of the motor vehicle via the motor-generator;
- determining a desired transmission input speed in the on-coming gear corresponding to transmission output speed;
- determining a target trajectory of a magnitude of output torque during the down-shift;
- commencing engagement of the on-coming clutch;
- determining a magnitude of torque transmitted by the on-coming clutch;
- applying a first measure of torque to the transmission by the motor-generator;
- continuing the engagement of the on-coming clutch to achieve the determined magnitude of output torque in the on-coming gear;
- determining whether a magnitude of torque transmitted by the off-going clutch is below a predetermined torque threshold;
- releasing the off-going clutch if the off-going clutch torque is below the predetermined torque threshold;
- applying a second measure of torque to the transmission by the motor-generator;
- determining whether a slip speed of the on-coming clutch is below a predetermined slip speed threshold value;
- and
- completing the engagement of the on-coming clutch to achieve the desired transmission input speed and the determined magnitude of output torque in the on-coming gear if the slip speed of the on-coming clutch is below the predetermined slip speed threshold value, sufficiently such that the output torque disturbance during the power-off down-shift is minimized.
A method for controlling a power-on up-shift in a multi-speed automatically-shiftable transmission employed in a hybrid motor vehicle, and for reducing an output torque disturbance in the transmission during the up-shift, the vehicle having an engine and a motor-generator, the engine and the motor-generator each operatively connected to supply torque to the transmission for driving the vehicle, the method comprising:
- initiating the transmission power-on up-shift from an off-going gear to an on-coming gear via an off-going clutch and an on-coming clutch;
- determining a desired transmission input speed in the on-coming gear corresponding to transmission output speed;
- determining a target trajectory of a magnitude of output torque during the up-shift;
- commencing engagement of the on-coming clutch;
- determining a magnitude of torque transmitted by the on-coming clutch;
- modulating the supply of torque from the motor-generator to the transmission;
- modulating the supply of torque from the engine to the transmission;
- continuing the engagement of the on-coming clutch to achieve the determined magnitude of output torque in the on-coming gear;
- determining whether a magnitude of torque transmitted by the off-going clutch is below a predetermined torque threshold;
- releasing the off-going clutch if the off-going clutch torque is below the predetermined torque threshold;
- determining whether a slip speed of the on-coming clutch is below a predetermined slip speed threshold value;
- and
- completing the engagement of the on-coming clutch to achieve the desired transmission input speed and the determined magnitude of output torque in the on-coming gear if the slip speed of the on-coming clutch is below the predetermined slip speed threshold value, sufficiently such that the output torque disturbance during the power-on up-shift is minimized.
Dependencies are inferred from the claim text.