Driving force control method and device for hybrid vehicle

A driving force control device for a hybrid vehicle equipped with an internal combustion engine, a driving force transmission mechanism for transmitting driving force of the internal combustion engine to drive wheels, and an electric motor coupled to the internal combustion engine and capable of outputting driving force to the driving force transmission mechanism, the driving force control device comprising:

• an average torque estimation part operable to estimate an average torque output by the internal combustion engine;
• a torque fluctuation component estimation part operable to estimate a torque fluctuation component of the torque output by the internal combustion engine;
• a countertorque setting part operable to set a countertorque for suppressing the estimated torque fluctuation component;
• and
• an electric motor control part operable to control the electric motor to output the set countertorque, wherein
• the countertorque setting part is operable, under a condition that an engine speed of the internal combustion engine is constant, when the average torque output by the internal combustion engine is less than a first given value at which the driving force from the internal combustion engine balances with a traveling resistance of the hybrid vehicle, to set the countertorque such that, as the average torque output by the internal combustion engine becomes larger, an absolute value of an amplitude of the countertorque becomes larger, and
• the countertorque setting part is further operable, under the condition that the engine speed of the internal combustion engine is constant, when the average torque output by the internal combustion engine is greater than the first given value, to set the countertorque such that, as the average torque output by the internal combustion engine becomes larger, the absolute value of the amplitude of the countertorque becomes smaller.