Red Dot Corporation

Onan Corporation

Gary P Hansen

Peter M Hawkins

Ronald J Mellum

Deborah A Klinkert

Glennard M Kline

Ronald G McFarlane

The present invention is directed to an auxiliary power unit for use with a vehicle, typically a truck. The truck has a cab and a sleeper to which the auxiliary power unit provides auxiliary air conditioning and heating. The truck also has a cab evaporator, a sleeper evaporator, a compressor, a condenser, and a plurality of refrigerant lines, a cab heater, a sleeper heater, and a plurality of coolant lines. The auxiliary power unit has an auxiliary evaporator and a plurality of auxiliary refrigerant lines. The auxiliary evaporator is arranged in series with the sleeper evaporator and the sleeper heater. The auxiliary refrigerant lines are separate and distinct from the truck's plurality of refrigerant lines. The auxiliary power unit also has a plurality of auxiliary coolant lines which are interconnected with the truck's plurality of coolant lines. The interconnection is accomplished in such a way that the auxiliary power unit can provide heat to the sleeper heater when the truck engine is running or when the truck is not running. If the coolant becomes excessively hot, a by-pass thermostat and valve direct the coolant to an auxiliary radiator. The auxiliary power unit has an auxiliary control panel in the sleeper to provide control of the heating and cooling in the sleeper when the truck engine and/or auxiliary engine is running.

Auxiliary power unit

A housing (28) has parallel passageways (30). Each passageway (30) has an inlet port (34) and an outlet port (32). A valve stem (26) with a head (36) reciprocates in each passageway (30) to control the outlet port (32). A flat plate (22) rotates perpendicularly to the stems (26) and has flat surface portions (48) and cavities (46). The positioning of portions (48) and cavities (46) is programmed to bring one of them into alignment with each stem (26) when plate (22) is in any one of a number of predetermined positions. When a portion (48) is moved into alignment, it bears against the head (36) and moves the stem (26) inwardly against a spring (38) into a second position. When a cavity (46) is moved into alignment, the stem (26) is urged into its first position by spring (38) and its head (36) extends into the cavity ( 46). Each stem (26) carries an O-ring seal (40) which is on one side of outlet port (32) when stem (26) is in its first position and on the other side of port (32) when stem (26) is in its second position. Ports (34, 32) communicate with each other when stem (26) is in its first position. Seal (38) blocks this communication when stem (26) is in its second position. Preferably, a manifold (64) communicates with each inlet port (34).

Programmable multiport switch

A desired temperature within the passenger compartment (10) of a motor vehicle is selected by occupant movement of a control lever (80) for a variable resistor (VR2). The temperature of conditioning air being supplied to the compartment is measured by a thermister (72). The two temperatures are electronically compared. If the measured temperature is higher than the selected temperature, a solenoid (62) is energized which moves a control valve (48) in a position allowing passage of pressurized air into an air cylinder (26). The air cylinder (26) functions to close a valve (22) in a water line (18, 20) which extends from the engine cooling system to a heat exchanger (24) located within the conditioning air duct (12). When the temperature of the conditioning air falls below the selected temperature level, the solenoid (62) is de-energized and a spring (54) moves the control valve (58) into a position in which it blocks flow of compressed air to the air cylinder (26) and vents the air cylinder to the atmosphere. A spring (34) in the vented air cylinder (26) moves the valve (22) in the water line to an open position. Hot water from the engine cooling system is then able to flow into the heat exchanger (24) and heat the conditioning air.

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Federal Way, WA, United States of America

Gary P Hansen