Method and systems for an auxiliary power unit

An auxiliary power unit (APU) of a vehicle, comprising:

• a rectangular housing including a top wall and a base frame arranged opposite the top wall, the base frame including a plurality of elongate cavities;
• an air vent arranged across a length of the top wall, a first opening of the air vent coupled to an aperture in the top wall;
• an engine;
• a compressor rotationally coupled to the engine via a clutch and fluidly coupled to a compressor cooler coupled to the first opening of the air vent;
• and
• an alternator rotationally coupled to the engine, each of the engine, compressor, and alternator coupled directly to the base frame and contained entirely within an interior of the rectangular housing,
• wherein a second opening of the air vent is arranged perpendicular to the top wall and flush with a side wall of the rectangular housing, the side wall arranged parallel to a longitudinal axis of the vehicle, and perpendicular to and coupled to each of the top wall and the base frame, and
• wherein the side wall further comprises a plurality of apertures for an engine air inlet, a compressor air inlet, and a compressor air outlet.

A vehicle, comprising:

• a radiator cab including a rectangular space positioned directly above a platform of the vehicle;
• and
• an auxiliary power unit (APU) adapted to fit within the rectangular space, the APU comprising:
• a rectangular housing including a base unit, a top wall, and four side walls coupled between the top wall and the base unit;
• an engine, a compressor, and an alternator, all mounted to the base unit in a triangular orientation where the engine is arranged proximate to a first side wall of the four side walls and the compressor and alternator are arranged adjacent to one another and proximate to a second side wall of the four side walls, the second side wall arranged opposite to the first side wall, the first side wall and second side wall arranged parallel to a longitudinal axis of the vehicle;
• and
• an air vent coupled to and extending across a length of the top wall from an aperture in the top wall, proximate to the first side wall, and to the second side wall, such that an opening of the air vent at the second side wall is arranged flush with the second side wall,
• wherein the second side wall further comprises a plurality of apertures for an engine air inlet, a compressor air inlet, and a compressor air outlet.