Regeneration control device, hybrid vehicle, regeneration control method, and computer program

A regeneration control method of a hybrid vehicle that has an engine and an electric motor, is capable of driving by the engine or the electric motor or capable of driving by cooperation of the engine and the electric motor, and regeneratively generates power by the electric motor at least during deceleration, and uses regenerative torque generated by the regenerative power generation of the electric motor during the driving by only the electric motor as braking force, comprising:

• a first comparison step for, when the regenerative torque generated by regenerative power generation in the electric motor is used as the braking force during deceleration of the hybrid vehicle traveling using only the electric motor, comparing a preset target deceleration with an actual deceleration caused by the regenerative torque generated by the regenerative power generation;
• a step of controlling for, in a case where a result of comparison of the comparison unit indicates that a state in which the actual deceleration is equal to or lower than the target deceleration occurs in a predetermined pattern though the electric motor is generating maximum regenerative torque, causing the vehicle to travel using both the engine and the electric motor in a cooperative manner during a next deceleration after a current deceleration has been finished, such that engine braking of the engine and the regeneration torque of the electric motor are both used as a braking force;
• a second comparison step for, when both the engine braking of the engine and the regenerative torque of the electric motor are used as the braking force, comparing the actual deceleration obtained by using both the engine brake of the engine and the regenerative torque of the electric motor as the braking force with the target deceleration;
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• a step of controlling for, when a comparison result of the second comparison unit indicates that the actual deceleration reaches the target deceleration and the regenerative torque of the electric motor is equal to or less than a predetermined value, causing the vehicle to travel using only the electric motor to use the regenerative torque of the electric motor as the braking force.