Patent ID: 8706335

Claim:
A method of operating a hybrid drive unit ( 1 ) comprising a first drive-power source ( 2 ), in the form of a supercharged internal combustion engine, and a second drive-power source ( 3 ), comprising an electric machine which is operable as a generator for charging an energy accumulator ( 4 ) that co-operates therewith and as a motor for discharging the energy accumulator ( 4 ), such that as a function of an output torque desired by a driver, a first drive torque can be called for from the first drive-power source ( 2 ) and a second drive torque called for from the second drive-power source ( 3 ) operating as a motor, the method comprising the steps of: when the driver indicates a desire for an increased output torque, one of: (a) increasing a time span during which the first drive torque reaches the increased output torque desired by the driver in comparison to a first drive torque normally achieved by the supercharged internal combustion engine, in a non-supercharged aspiration to achieve operation of the hybrid unit ( 1 ) with reduced fuel consumption and reduced emissions; and (b) decreasing a slope of an initial torque increase by which the first drive torque reaches the increased output torque desired by the driver in comparison to a first drive torque normally achieved by the supercharged internal combustion engine, in a non-supercharged aspiration to achieve operation of the hybrid unit ( 1 ) with reduced fuel consumption and reduced emissions; and supplementing the first drive torque with the second drive torque to achieve the increased output torque and compensate for the increased time span during which the first drive torque reaches the increased output torque desired by the driver or the decreased slope of an initial torque increasing by which the first drive torque reaches the increased output torque desired by the driver when the charge condition of the energy accumulator ( 4 ) is high, such that if the increased output torque desired by the driver is increased either stepwise or abruptly, the first drive torque demanded from the first drive-power source ( 2 ) is increased with a substantially constant slope to the increased output torque desired by the driver (A to D), at a torque time gradient less than that of a maximum initial time gradient (A to C) that is deliverable by normal engine aspiration without supercharging.