Gm Global Technolgoy Operations, Inc.

Shannon E Reeves

Lan Wang

Jy-Jen F Sah

William Leonard Aldrich, Iii

Michael J Pitsch

Jinming Liu

A method is provided for controlling a hybrid electric vehicle. The vehicle includes at least one motor-generator, an internal combustion engine employing a camshaft and a camshaft phaser, and an energy-storage device operatively connected to the engine and to the at least one motor-generator. The method includes determining whether a deceleration of the vehicle is desired, and ceasing a supply of fuel to the engine when the deceleration is desired. The method additionally includes regulating the camshaft phaser to a predetermined fuel cut-off position when the supply of fuel to the engine has been ceased, such that a magnitude of compression pulses in the engine is reduced relative to when the engine is being fueled. A system for controlling the hybrid electric vehicle and for executing the above method is also provided.

System and method for controlling an engine in a hybrid vehicle

A hybrid electric vehicle has a controller, an engine, a traction motor, and a transmission. The controller is configured for calculating, using a costing function, the total system losses incurred at each operating point of the HEV, including the losses for each of the engine, the traction motor, and the transmission. The controller selectively modifies the calculated cost of at least one of the engine, the traction motor, and the transmission in a designated one of the transmission states as a function of transmission fluid temperature. An optimal transmission state is then selected as the state having the optimal cost relative to the other transmission states. Selectively modifying the calculated cost may include penalizing the cost of using designated transmission states when the measured fluid temperature exceeds certain calibrated temperature limits. Designated operating states may be disabled above an upper temperature limit to protect the transmission from overheating.

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Wixom, MI, United States of America

Shannon E Reeves