Auxiliary power unit heating system

Abstract

An engine heating system for vehicles comprising an engine, a vehicle compartment heating system including fluid conduits extending from the engine to a heating unit and extending back to the engine, an auxiliary power unit on the vehicle including an auxiliary engine having a water pump driven by the auxiliary engine including fluid conduits extending from the auxiliary engine to a second heating unit located in a compartment of the vehicle and extending back to the auxiliary engine, fluid conduits extending from the engine to the second heating unit and extending back to the engine, a valve disposed in the fluid conduit between the second heating unit and the engine, the valve capable of receiving a signal, a temperature switch for detecting a coolant temperature, the temperature switch providing a signal to operate the valve, the valve allowing coolant circulation through the second heating unit to the main engine when the main engine is in operation or the coolant temperature is greater than a predetermined temperature, and the valve closed when the main engine is not in operation or the coolant temperature is below a predetermined temperature.

Description

FIELD OF THE INVENTION [0001] The invention relates to an auxiliary power unit heating system, and more particularly, to an auxiliary power unit heating system comprising a means for selectively isolating a cabin heating unit in the auxiliary power unit cooling system from a main engine coolant system while also providing heating capability for the main engine. BACKGROUND OF THE INVENTION [0002] Generally, large diesel engines are not shut down during cold weather conditions due to the difficulty in restarting. Diesel engines do not have the benefit of an electric spark to generate combustion and must rely on heat generated by compressing air to ignite fuel in the engine cylinders. In low temperature conditions (ambient temperatures below about 40° F.), two major factors contribute to the difficulty in starting a diesel engine. First, cold ambient air drawn into the engine must be increased in temperature sufficiently to cause combustion. Second, diesel fuel tends to exhibit poor vi...

AI Technical Summary

Benefits of technology

[0007] The primary aspect of the invention is to provide an auxiliary power unit heating system, and more particularly, an auxiliary power unit heating system comprising a means for

Problems solved by technology

Generally, large diesel engines are not shut down during cold weather conditions due to the difficulty in restarting.

Diesel engines do not have the benefit of an electric spark to generate combustion and must rely on heat generated by compressing air to ignite fuel in the engine cylinders.

First, cold ambient air drawn into the engine must be increased in temperature sufficiently to cause combustion.

Second, diesel fuel tends to exhibit poor viscous qualities at low temperatures, making engine starting difficult.

Diesel trucks that must operate in extremely cold environmental conditions must be run continuously, at high fuel cost, or, when shutdown, must be drained of engine coolant and provided supplemental electrical service and heating, also at high cost.

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