Wheel slip flare controller using clutch control
AssigneeFord Global Technologies, LLC
InventorsCory Benson LaRoche, Bradley Dean Riedle, Stephen Michael Cicala, Jianping Zhang
Life of this patent
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Abstract
A method is proposed to complete a power-on upshift while a vehicle encounters wheel slip conditions such as driving in loose sand. The wheels slip conditions may be detected based on a maximum rate of change of an output shaft exceeding a threshold. In response to the wheel slip conditions, one or more shift parameters may be adjusted to bias the shift toward a tie-up and decrease the chance of a flare. These modified shift parameters may include an increased stroke pressure, a delayed off-going clutch release timing, and an increased ratio change capacity.
Claims20
A method of controlling a transmission, comprising:
- in a non-wheel-slip condition, upshifting under power from a first transmission ratio to a second transmission ratio using a first set of shift parameters;
- and
- in response to a wheel-slip condition, upshifting under power from the first transmission ratio to the second transmission ratio using a second set of shift parameters;
- wherein
- the second set of shift parameters bias a respective torque phase towards tie-up relative to the first set of shift parameters.
A method of controlling a transmission, comprising:
- during a power-on first upshift from a first transmission ratio to a second transmission ratio, in response to a derivative of an output shaft speed remaining below a threshold during a preparatory phase of the first upshift, completing the first upshift using a first set of shift parameters;
- and
- during a power-on second upshift from the first transmission ratio to the second transmission ratio, in response to the derivative of the output shaft speed exceeding the threshold during a preparatory phase of the second upshift, completing the second upshift using a second set of shift parameters;
- wherein
- the second set of shift parameters bias a torque phase of the second upshift towards tie-up relative to a torque phase of the first upshift.
A transmission comprising:
- an output shaft having an output shaft speed;
- on-coming and off-going clutches;
- and
- a controller programmed to
- during a power-on first upshift, in response to a derivative of the output shaft speed remaining below a threshold during a preparatory phase of the first upshift, release the off-going clutch with first clutch release timing and engage the on-coming clutch using a first stroke pressure and a first ratio change torque capacity;
- and
- during a power-on second upshift, in response to the derivative of the output shaft speed exceeding the threshold during a preparatory phase of the second upshift, release the off-going clutch with second clutch release timing and engage the on-coming clutch using a second stroke pressure and a second ratio change torque capacity;
- wherein
- the second stroke pressure, second ratio change torque capacity, and second off-going clutch release timing bias a torque transfer phase towards tie-up relative to the first stroke pressure, first ratio change torque capacity, and first off-going clutch release timing.
Dependencies are inferred from the claim text.