Auxiliary power unit and method for a vehicle

An auxiliary power system configurable within a vehicle or construction equipment having a main engine and a cabin area, wherein cooled air is supplied within the cab using an air conditioning compressor of an air conditioner within the vehicle that is ordinarily driven by a primary belt-driven pulley on the air conditioning compressor receiving power from the main engine when the main engine is activated, the auxiliary power system comprising:

• an auxiliary engine having a power coupling, wherein the auxiliary engine receives fuel from a fuel tank of the vehicle or the construction equipment during operation;
• a hydraulic power system coupled to the auxiliary engine via the power coupling, wherein the hydraulic power system converts hydraulic power to mechanical power;
• a compressor drive having a second drive belt mechanically connected directly to the hydraulic power system to receive the mechanical power;
• and
• the air conditioning compressor within the vehicle having a second drive pulley on the air conditioning compressor configured to directly receive the mechanical power from the second drive belt of the compressor drive, wherein the air conditioning compressor is activated for the air conditioner to provide the cooled air when the auxiliary engine is activated.

A method for operating an air conditioning compressor of an air conditioner in a vehicle or construction equipment having a cabin and a main engine wherein the air conditioning compressor is ordinarily driven by a primary belt-driven pulley on the air conditioning compressor receiving power from the main engine when the main engine is activated, the method comprising:

• activating an auxiliary engine coupled to a hydraulic pump through a power coupling, wherein the hydraulic pump moves hydraulic fluid from a hydraulic reservoir;
• receiving the hydraulic fluid from the hydraulic pump at a hydraulic compressor drive motor;
• converting hydraulic power to mechanical power at the hydraulic compressor drive motor;
• providing the mechanical power from the hydraulic compressor drive motor directly to a compressor drive having a second drive belt;
• and
• activating the air conditioning compressor with a second drive pulley on the air conditioning compressor driven directly by the second drive belt of the compressor drive, wherein the air conditioning provides cooled air when the auxiliary engine is operating.