Abstract: A hybrid electric drive system is provided having a heat engine, a catalytic converter, and an electric storage device having a state of charge. The drive system also includes a state of charge sensor and a device for heating the catalytic converter in response to the state of charge of the electric storage device being less than a predetermined state of charge.

Abstract: An integrated system including a residence and an automobile utilizes environmental energy, such as solar energy, as the primary energy source, and the automobile provides a backup or supplementary source of energy for this system. An exemplary system has photovoltaic and thermal collectors associated with the residence for collecting radiant solar energy and converting a portion thereof to electricity and to heat, and residential energy storage means for storing energy generated within the integrated energy system; hybrid electric drive means associated with the automobile in this exemplary system includes batteries for storing electrical energy generated within the integrated energy system, an electrically energized motor to propel the automobile, and a liquid-fueled combustion engine for driving an associated electrical generator to function as a backup or supplementary source of energy for both the residence and the automobile.