Patent Application
20070051491
The present invention relates generally to heating and cooling of vehicles, and, more particularly, to heating and cooling of internal combustion engine driven vehicles when the vehicle is not in motion.
Previously, when vehicles, such as trucks, ambulances and busses have been parked overnight or for extended periods of time with occupants present it has been necessary to maintain a comfortable interior environment, such as by heating and cooling the cab or compartment of the vehicle, according to the exterior environment. Typically, the primary vehicle engine or a smaller secondary engine has been used by running it at idle to provide the source of thermal fluid and power for this function.
However, running an internal combustion engine of any size for this purpose has certain disadvantages, including excessive fuel costs, air pollution, noise, leakage, and maintenance costs. Alternative systems have been proposed, but those have typically been relatively difficult and expensive to install, required parallel systems (independent for heating and for cooling) and/or have taken up more interior space within the cab that is desired. Moreover, many vehicles, such as ambulances, have secondary thermal containers, such as medication refrigerators, that are placed within the occupied portions of the vehicle and require either and independent or competing thermal fluid source.
Accordingly, it is an object of the present invention to provide and improved climate control system for use in a vehicle while the vehicle is not in motion. Another object of the present invention is to provide a vehicle climate control system that:
These and other objects of the present invention are obtained by the provision of an auxiliary heating and cooling system for vehicles wherein there are two alternative sources of primary thermal fluid, one being driven by the vehicle engine and the other by an electrical source separate from the vehicle, but both using the same secondary thermal fluid, operable under a lower pressure and being water based. Each of the primary fluids is alternatively connectable to a heat exchanger receiving the secondary fluid. The secondary fluid is connected to one or more fluid to air heat exchangers spaced as desired in the passenger compartment and to any internal container or constant temperature box heat exchangers, such as a refrigerator, as desired within the compartment. This invention permits use of modular components mounted from the exterior of the vehicle. Various fluid flow directional valves can be used as desired for flexibility in temperature orientation.
Other objects, advantages and novel features of the present invention will now become readily apparent to those skilled in the art from the following drawings and detailed description of preferred embodiments.
The drawings show schematically preferred embodiments of the present invention as mounted on a motor vehicle such as a truck cab. The component descriptions in the drawings for each numbered component are as follows: 1—engine driven compressor, 2—OWM or main loop remote condenser, 3—accumulator, 4—heat exchanger (three liquid chiller), 5—bypass, 6—electrical 110 v/220 v compressor, 7—remote condenser, 8—expansion device, 9—water/glycol tank with water heater, 9a—bypass, 10—metering valve, 11—12 v DC water pump, 13—normally open valve, 14—normally open valve, 15—OEM normally closed valve, 16—OEM normally closed valve, 17—normally closed valve, 18—engine heater loop, 19—constant temperature cabinet with chiller plate (19a) and heating element (19b), 20—normally open valve, 21—normally closed valve, 22—expansion device, 23—refrigerant loop box, 24—water tank box, 25—normally closed valve. The additional component descriptions in the drawings are incorporated herein by reference.
Typical fluid flow directions are indicated by the arrows adjacent to the fluid flow lines in the drawings. The engine driven compressor (conventional in nature and standard with most vehicles), refrigerant loop box, water tank box are all preferably mounted on the exterior of the occupant compartment or cab. Electricity for the 110 v compressor is, for example, provided from a source separate from the vehicle, as via an electrical extension cord. The system is illustrated for coolant, but can be alternatively run for heat. Each component is mounted as a modular unit, so that any number of modules can be added, replaced and used as desired. Except for the fluid to air heat exchangers and blowers and the constant temperature cabinet (refrigerator, for example), it is generally preferred to have all components mounted on the exterior of the occupant compartment or cab.
The valves are arranged to provide maximum operational efficiency. For example, the water tank, acting as a reservoir, can be bypassed during start-up operation to allow thermal treatment of the air to occur sooner. Various conventional sensors and/or timers can be included to monitor internal air temperature or secondary fluid temperature to control valve operation to this effect and to allow the passenger compartment to have a different temperature from the constant temperature cabinet. The secondary fluid is, for example, a water based fluid or water gycol mixture or similar non-toxic fluid.
Additional electrical heating elements can be used, for example, in the constant temperature compartment and/or the water tank to provide supplemental fluid temperature regulation as needed. These structure of these heating elements is preferably conventional in nature.
In general, the present invention uses two sources of primary thermal fluid alternatively (from the engine driven compressor or from the hermetic compressor) to heat or cool an operational secondary fluid. Heat exchangers are used rather than a refrigerant-to-air evaporator in the cooling mode of operation. The present invention reduces refrigerant leakage by not requiring a highly pressurized refrigerant fluid (on a rough order of magnitude, allowing a drop in pressure from 200 psi to 40 psi). Using smaller fluid tubes of the present invention takes up less space that conventional air ducts within the passenger compartment. The modular construction mounted outside of the passenger compartment allows less expensive installation and servicing of the system.
Although the present invention has been described above and shown in the drawings with respect to certain preferred embodiments, that is done by way of illustration and example only. Those persons or ordinary skill in the relevant and technology art will readily understand now from this disclosure that many variations can be made of the subject invention. For example, instead of using this invention to both heat and cool a vehicle, the primary/secondary fluid arrangement of the present invention could be used only for refrigeration or cooling of the vehicle while electrical heating of water in only the secondary loop could be used for the vehicle heating mode. Another variation of the present invention would be to use only a single primary fluid loop, such as for refrigeration or cooling, and omit use of the alternative primary fluid loop. Accordingly, the spirit and scope of the present invention are limited only by the terms of the following claims as ultimately allowed.
