US Patent 7150159 Hybrid auxiliary power unit for truck

A hybrid auxiliary power system for a vehicle provides auxiliary electrical power, cooling, and heating while the main engine of the vehicle is turned off. An auxiliary engine directly drives an air-conditioner compressor. A condenser condenses the refrigerant and supplies it to an evaporator. A blower moves air through the evaporator and into the vehicle. The engine also drives an AC generator, which supplies air to a battery charger. The battery charger supplies DC voltage to charge the battery of the vehicle as well as power to the blower of the auxiliary air-conditioner.