Patent ID: 8292777

Claim:
A method of controlling a hybrid vehicle ( 1 ) during regenerative deceleration, the vehicle ( 1 ) comprising an internal combustion engine ( 5 ); a servocontrolled mechanical power train ( 7 ) having a number of gears and interposed between the internal combustion engine ( 5 ) and drive wheels ( 3 ); and at least one reversible electric machine ( 13 ); the method comprising: determining deceleration of the vehicle ( 1 ); upon determining deceleration of the vehicle ( 1 ), operating the reversible electric machine ( 13 ) as a generator to regenerate part of the kinetic energy of the vehicle ( 1 ); establishing a respective minimum speed of the internal combustion engine ( 5 ) for each gear of the servocontrolled mechanical power train ( 7 ); determining and engaging the highest gear which, combined with the current state of motion of the vehicle ( 1 ), runs the internal combustion engine ( 5 ) at higher than the respective minimum speed; keeping the current gear engaged as long as the internal combustion engine ( 5 ) runs at higher than the respective minimum speed to minimize engine braking; and downshifting by one gear when the internal combustion engine ( 5 ) runs at lower than the respective minimum speed; wherein the respective minimum speed of the internal combustion engine ( 5 ) for each gear of the servocontrolled mechanical power train ( 7 ) increases from low to high gear so that the minimum speed of a lower gear is lower than that of a higher gear.