Hybrid drive system

In an electric vehicle having an ongoing duty cycle, a hybrid drive system, comprising:

• electric motor/generator means for moving said vehicle;
• primary energy source means in electrical contact with said electric motor/generator means for selectively energizing said electric motor/generator means, said primary energy source means including a low-rate energy storage system;
• secondary energy source means in electrical contact with said electric motor/generator means and said primary energy source means, said secondary energy source means including a variable-rate energy storage system for providing a constant energy output to said electric motor/generator means during emission operation in accordance with the average-rate of power consumption of said vehicle;
• supplemental energy source means in electrical contact with said electric motor/generator means and said primary energy source means for selectively energizing said electric motor/generator means, said supplemental energy source means including a high-rate energy storage system;
• control means for determining the average power consumption of said vehicle during emission operation throughout said ongoing duty cycle and controlling the extent to which each of said energy source means energizes said electric motor/generator means to move said vehicle, said control means in electrical contact with said primary, secondary and supplemental energy source means such that said vehicle may be efficiently operated in both emission and non-emission modes in accordance with environmental restrictions and operator imposed power demands.

In an electric vehicle having a hybrid drive system and electric motor/generator means, a method of selectively energizing said electric motor/generator means to efficiently move said vehicle during emission and non-emission operation in accordance with environmental restrictions and operator imposed power demands, comprising the steps of:

• providing plural electrical energy source means in electrical contact with said electric motor/generator means, said plural electrical energy source means including a variable-rate energy storage system, a low-rate energy storage system and a high-rate energy storage system;
• providing control means in electrical contact with said plural electrical energy source means and said electric motor/generator means;
• determining the average power consumption of said vehicle during emission operation;
• and
• enabling said variable-rate energy storage system during emission operation to provide a constant energy output to said electric motor/generator means in accordance with said determined average power consumption of said vehicle, and to recharge said low-rate and high-rate energy storage systems when the instantaneous power demand of said vehicle is less than said determined average power consumption, such that the peak power demands of said vehicle may be fairly satisfied by the high-rate and low-rate energy storage systems.