Refrigeration – Gas controller or director – Gas passage over or through indirect heat-transfer container...
Reexamination Certificate
2001-06-18
2002-10-01
Jiang, Chen-Wen (Department: 3744)
Refrigeration
Gas controller or director
Gas passage over or through indirect heat-transfer container...
C062S244000, C062S434000
Reexamination Certificate
active
06457324
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to vehicle air conditioning systems, and more particularly to over-the-road or off-road or off-road vehicle air conditioning systems and refrigeration systems.
BACKGROUND OF THE INVENTION
Over-the-road or off-road vehicles, such as semi-tractor trailers and construction vehicles, are increasingly utilized to satisfy the transportation and construction needs of our economy. These increased needs result in increased utilization of these vehicles to the point where many are operated seven days a week and upwards of eighteen (18) to twenty (20) hours a day with a two person crew or multiple shift operations. This increased utilization is not simply a vehicle statement, but also includes a human factor as these vehicles are operated by at least a driver and often times by a driving team consisting of two individuals who share the duty of operating the vehicle. Since these vehicles are operated so extensively, increased driver and passenger comfort is essential, both in terms of environment temperature and physical space within the vehicle cab.
The need for environmental comfort during warm weather is satisfied through the use of an over-the-road or off-road vehicle air conditioning system, while the physical layout has been accommodated through new ergonomic interior designs, including reduced dash size, to maximize the available room within the vehicle cab for passenger occupation. Increased driver and passenger comfort may be further aided by the inclusion of a refrigerator or ice chest (cooler). Such devices are ideal for storing cold beverages and foods, or any other personal items which are desirably kept at low temperatures. This often allows a driver to remain on the road for longer periods of time between required stops for food and a cold drink.
Typical over-the-road or off-road vehicle air conditioning systems are of the compressor type. These air conditioning systems utilize a compressor, which is driven by a belt coupled to the engine to compress a refrigerant vapor under high pressure which is then circulated through a condenser to remove heat from the compressed high-pressure vapor and change it to a liquid state. The liquid refrigerant is then passed through an expansion valve which reduces the pressure on the refrigerant somewhat. This lower pressure refrigerant is then passed through an evaporator, which permits the return of the refrigerant to the vapor state, thereby removing heat from the air blown thereacross by an in-dash fan.
In a modern over-the-road or off-road vehicle, the main components of the refrigeration system, including the compressor and the condenser, are located remotely from the evaporator which is typically installed behind the dashboard air vents to provide cooling of the cabin air as described above, and from the condenser which is typically mounted with the vehicle radiator in the front of the engine compartment. Since the typical compressor vehicle air conditioning system is a closed loop system, the circulating high-pressure refrigerant must be passed from the remotely located components within the engine compartment to the vehicle cab-located evaporator and to the forward engine compartment, radiator located condenser via expensive high-pressure refrigeration hoses.
A typical installation includes the compressor and condenser in the engine compartment of the over-the-road or off-road vehicle, and utilizes multiple high-pressure refrigeration lines to couple these components through the firewall and into the cab behind the dash to the location of the evaporator, and to the radiator area of the engine compartment. Each of these high-pressure refrigeration lines require high-pressure couplings at each connection for the delivery and return of the high-pressure refrigerant in the air conditioning system.
As can well be imagined, both from the above-description as well as from personal experiences with vehicular air conditioning systems, this typical installation arrangement for an over-the-road or off-road vehicle air conditioning system is severely prone to leaks of the high-pressure refrigerant. These leaks occur at various locations, but are most frequent at the various couplings of the high-pressure hose which routes the high-pressure refrigerant from the condenser to the interior of the cab, under the dash, and to the location of the evaporator. Another frequent area for leaks occurs at the various couplings of the high-pressure hose which routes the high-pressure refrigerant from the compressor to the radiator area located condenser.
These leaks result in a reduced efficiency of the air conditioning system, expensive recharging of the system with new refrigerant, as well as a hazard to the environment through the escape of the refrigerant. An increased consciousness of the environmental impact that escaped refrigerant has on the planet, as well as increased government regulation regarding the inadvertent release of refrigeration refrigerant, has placed an increased emphasis on overcoming these problems.
In addition to the problem of leaks within the air conditioning system, the use of this type of system requires that expensive high-pressure refrigeration lines be utilized within the engine compartment, and between the engine compartment and the interior of the cab. In addition, expensive high-pressure couplings must also be utilized in an attempt to reduce the potential for leaks and catastrophic failure of the air conditioning system due to a failed connection of the high-pressure refrigeration lines. Also, because the refrigeration system is not closed until assembly of the vehicle takes place within the manufacturing assembly facility, the use of this type of system further burdens the assembly manufacturer by requiring that the initial purging and charging of the refrigeration system take place within the assembly plant of the vehicle itself. As mentioned above, since the use of refrigerant is a highly regulated process, requiring the manufacturing assembler to charge the refrigeration system greatly increases the cost associated with the manufacture of the vehicle.
In addition to:the problems associated with the typical air conditioning system just described, the inclusion of refrigerators or ice boxes (coolers) in the cab introduces additional problems. When coolers are used, the driver or passenger must purchase and partially fill the cooler with ice to keep the contents (food, drink, medicine, etc.) cool. Unfortunately, ice can only keep the contents cool for a relatively short period of time, as the ice will eventually melt. This melting is accelerated as the cover of the cooler is opened to gain access to the contents, as warm items are placed in the cooler, etc. As a result, the cooler tends to become filled with ice water, which causes many problems. Many coolers are prone to leaking the melted ice water. Further, emergency maneuvers may cause the cooler to shift and tip over, spilling the ice water and other content in the cab. These are obviously unwanted situations inside a vehicle. Further, the water from the melting ice often soaks the contents of the cooler. As a result certain products cannot be stored in the cooler without risking ruining them.
To overcome these drawbacks, vehicle refrigerators or cool boxes have been proposed. A common vehicle cool box is of the compressor type much like the aforementioned air conditioning systems. These cool boxes utilize a dedicated refrigeration circuit (separate from the air conditioning circuit discussed above) comprising a compressor, condenser, expansion valve and evaporator for the refrigerator. Therefore, when viewed from the overall vehicle level these systems require an additional compressor, an additional condenser, and additional expansion device, and an additional evaporator. Furthermore, since the compressor is driven by the engine and since the evaporator must be located within the cabin of the vehicle, these systems suffer the same drawbacks noted above with regard to air conditioning systems. Specifically, such system
Evans Phillip Carew
Gavin William David
Zeigler Terry A.
Bergstrom, Inc.
Jiang Chen-Wen
Leydig , Voit & Mayer, Ltd.
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