Methods and systems for assisted direct start control
AssigneeFord Global Technologies, LLC
InventorsFelix Nedorezov, Hong Jiang, Roger Lyle Huffmaster, Alex O'Connor Gibson, Gregory Michael Pietron, Seung-Hoon Lee
Life of this patent
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Abstract
Methods and systems are provided for reducing driveline unwinding during successive engine shutdown and restart operations. In one example, during an engine shutdown, torsion is maintained in a transmission gear-train until an engine restart is requested by engaging one or more transmission clutches while applying wheel brakes.
Claims17
A method of controlling a vehicle power-train including wheels, an engine and a transmission, comprising:
- selectively shutting down engine operation responsive to operating conditions and without receiving an engine shutdown request from an operator;
- before the engine is stopped and while positive drive torque is still transmitted through the transmission, grounding the transmission to the vehicle;
- maintaining the transmission grounded until restarting the engine;
- wherein grounding the transmission includes adjusting a clutch pressure to engage a transmission clutch, and locking the engaged transmission clutch to a frame of the vehicle;
- wherein a timing, with respect to engine speed, of the transmission grounding is adjusted to maintain an amount of torsional potential energy within a gear-train of the transmission;
- and
- wherein the amount of torsional potential energy is adjusted based on ambient temperature, the adjustment including increasing the amount of torsional potential energy within the gear-train as ambient temperature falls below a threshold.
A method of controlling a power-train of a vehicle, the power-train including an engine and an automatic transmission, the power-train coupled to driving wheels of the vehicle, the vehicle operated by an operator, the method comprising:
- selectively deactivating the engine responsive to operating conditions and without receiving an engine shutdown request from the operator;
- before the engine is stopped and while positive drive torque is still transmitted through the transmission:
- grounding the transmission to the vehicle, and activating wheel brakes, to maintain an amount of torsion in a transmission gear-train;
- and
- maintaining the transmission grounded with the amount of transmission gear-train torsion until an engine restart.
A vehicle system, comprising:
- a power-train including wheels, an engine, and an automatic transmission including one or more transmission clutches;
- wheel brakes;
- and
- a control system including non-transitory computer readable instructions to:
- selectively shut down engine operation responsive to operating conditions and without receiving an engine shutdown request from an operator;
- before the engine is stopped and while positive drive torque is still transmitted through the transmission, ground the transmission with wheel brakes activated to maintain an amount of torsion in the transmission;
- and
- maintain the transmission grounded with the amount of transmission torsion until an engine restart.
Dependencies are inferred from the claim text.