Abstract: An auxiliary power unit system for mobile service vehicles is provided that can provide DC power to DC-powered equipment. The system attaches to the power take-off port of the transmission and can provide power to the DC-powered equipment without idling the engine of the mobile service vehicle, thereby reducing fossil fuel consumption and engine exhaust emissions.

Abstract: A system and method is provided for converting wellhead pressure of natural gas wells, or for converting water head pressure of water towers, to rotational power for operating rotated equipment, such as electrical generators, electrical alternators, pumps, air compressors, and other rotated equipment.

Abstract: A system is provided for a product pump drive for pumping fluids or substances into or out of a tanker-trailer towed by a tractor, the system including an auxiliary diesel engine mounted on the tractor, the engine operating a hydraulic pump used to operate a hydraulic motor operatively coupled to a product pump. The system can further include a high-pressure shutdown mechanism to shut down the engine if the pressure of the hydraulic fluid pumped by the hydraulic pump exceeds a high-pressure threshold. The system can also include an air conditioning unit and/or an electrical generator operatively coupled to the auxiliary diesel engine.