US Patent 9211881 Control system for auxiliary power unit of a vehicle

A method of controlling an auxiliary power unit of a vehicle. The auxiliary power unit is in communication with an air conditioning system of the vehicle and includes an engine and an alternator coupled to the engine. The method includes determining a state of a compressor of the air conditioning system, the compressor including an off state and an on state, reducing an alternator load relative to the engine in response to the compressor being varied from the off state to the on state, increasing the alternator load relative to the engine after a predetermined time interval, and simultaneously operating the alternator up to an alternator load capacity and the compressor up to a compressor load capacity.