Abstract:
Method and apparatus for supplying refrigerated air to a localized volume in a vehicle, suitable for the transport of groceries and other perishables. The localized volume is created by insulated panels in the storage area of a vehicle. The chiller unit includes an air duct that contains inlet and outlet openings, an evaporator core and a fan. The evaporator core receives refrigerant fluid from a powered compressor and a condenser that are shared in common with the HVAC system that serves the passenger compartment. Although the compressor and condenser are shared, the chiller unit is separate and may be used independently of the HVAC system.

Description:
BACKGROUND OF THE INVENTION 
   The invention relates generally to the field of vehicle cooling systems and more specifically to method and apparatus for providing cooling to a localized volume within a vehicle. 
   Currently in motor vehicles, heating, ventilating, and air conditioning (HVAC) systems provide a controlled environment for the passenger compartment. Such systems are well known to be either manually or automatically controlled to maintain an environment within a temperature range that is selectable by a driver or passenger occupant, as desired. 
   It is also well known that when a vehicle is exposed to sun-loads or high ambient temperatures for a prolonged period of time, both the passenger compartment and the cargo storage area become excessively hot. While most HVAC systems can provide rapid cool-down of the passenger compartment to a temperature that is comfortable for the human occupants, the cooling of the cargo storage area lags or doesn&#39;t happen. In any event, without separate cooling, the transporting of groceries or other perishables in the storage compartment requires the use of insulated containers or short trips to prevent spoilage or melting. 
   Several attempts have been made to modify vehicles and their HVAC systems to provide heated or cooled air to cargo storage areas in order to maintain such areas at desired temperatures. 
   U.S. Pat. No. 5,839,293 shows a ducting system which directs air from the vehicle HVAC system, intended for heating, ventilating and cooling the passenger compartment to the cargo area of the vehicle. A valve is shown which allows heated or cooled air from the HVAC to be directed to either the passenger compartment or to the cargo area, as desired. 
   U.S. Pat. No. 5,203,833 shows a food storage container with air ducts that are connected into the conduit which carries conditioned air for the passenger compartment. The ducts of the food storage container divert conditioned air to the container, allowing the air to pass through the container and return to the conduit. The interior of the food storage container appears to be maintained at the same temperature as the conditioned air supplied to the passenger compartment. 
   U.S. Pat. No. 4,936,103 shows an insulated food container in the storage compartment of a vehicle and an air conduit extending between an air vent on the dash of the vehicle and the container. Heated or cooled air from the HVAC system is forced directly into the food container. An auxiliary fan can be mounted within the air conduit to increase the flow of air to the food container. 
   Commonly assigned U.S. Ser. No. 10/605,181 filed Sep. 12, 2003 discloses a system for controlling the fluid flow to a plurality of heat exchangers. 
   Commonly assigned U.S. Ser. No. 10/605,179 filed Sep. 12, 2003 discloses a system for cooling a vehicle battery such as that used to power an electric vehicle. 
   Applicant has recognized that it would be desirable to provide a system which allows for environmental cooling of the cargo area separate from and without adversely affecting the heating, cooling, or ventilating that occurs in the passenger compartment of a vehicle. 
   SUMMARY OF THE INVENTION 
   The present invention includes apparatus and method for providing controlled cooling to the air in a localized volume suitable for storing groceries and the like. In a passenger vehicle which contains an HVAC system for controlling the interior temperature of the passenger compartment, the invention comprises walls, flooring and cover to define the localized volume and insulation to retard the migration of heat to the localized volume. An air duct is provided with openings in communication with the localized volume to receive air returned from the localized volume and to direct the flow of air supplied to the localized volume. An evaporator core/heat exchanger is located within the air duct and is connected to receive refrigerant fluid from a condenser shared in common with the HVAC system and to cool air flowing in the air duct. An air movement device for creating a flow of air through the air duct also is located within the air duct. A sensor is located within the air duct for sensing the temperature of air flowing through the air duct. A control device is connected to the sensor and to the air movement device for regulating the flow of air over the evaporator core and into the localized volume as necessary to cool and maintain the temperature of the localized volume within a predetermined range of temperatures. The range may be either preset or manually adjustable at the chiller or remotely, depending on the desired installation. 
   It is an object of the present invention to provide a cooled space within an automotive vehicle that is suitable for transporting groceries and other perishables. 
   It is another object of the present invention to provide a cooling apparatus that will recirculate and cool the air within a localized volume such as the cargo space of a passenger vehicle. 
   It is a further object of the present invention to provide a cooling apparatus that will cool a localized volume within a vehicle independent of the heating, cooling or ventilating that takes place in the passenger compartment of a vehicle. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a cut-away rear view of a vehicle containing the preferred embodiment of the present invention. 
       FIG. 2  is a schematic top view of a vehicle containing an embodiment of the present invention. 
       FIG. 3  is a schematic representation of the control system used in the present invention. 
       FIG. 4  is a functional view of an alternative embodiment of the present invention. 
       FIG. 5  is a functional view of another alternative embodiment of the present invention. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   In  FIG. 1 , a cut-away rear view of a vehicle  10  is shown to contain the present invention. The vehicle is represented by a passenger compartment  12  and a rear cargo storage area  40 . In order to define a localized volume for transporting and cooling groceries or other perishables, insulated wall panels  104 ,  105 , and  106  are shown. Another insulated wall panel contained on the rear door or lift gate (not shown) completes the lateral definition of the volume. The floor  108  already contains insulation for the purpose of noise suppression, but more may be added if necessary. An insulated cover  102  may be a hinged panel or a roll up shade type to provide vertical access to the space. 
   The grocery chiller unit  100  is shown contained within the vehicle  10  adjacent to wall panel  106 . The chiller unit  100  includes an air duct  110  with a pair of openings  112  and  114  to remove and supply air to the localized volume  40 . An evaporator core  120  is also contained within air duct  110  to refrigerate the air flowing therethrough. A variable speed fan or blower  130  also is included within the air duct  110  to act as an air movement device. The fan  130  forces the air through the duct  110  and the evaporator core  120  as well as providing the supply and removal of cooled air to and from the localized volume. Temperature sensors  124  and  126  are provided next to the respective duct openings  114  and  112 . 
   Although not shown, it is conceived that as an alternative to an roll-up or hinged cover  102 , one could attach a light weight heat reflecting and/or or insulating blanket to wall  106  above the duct opening  114  to contain the air flow beneath the blanket. Alternatively, one could also make wall  104  movable in order to reduce the size of the localized volume  40  as desired to improve the efficiency of the chiller unit  100 . 
   A schematic top view of the vehicle  10  is shown in  FIG. 2  with the defined passenger air space  12  and localized space  40 . A compressor  200  and condenser  206  serve to provide refrigerant fluid to both the HVAC system  300  and the grocery chiller unit  100  through controlled shut-off valves  207  and  208 , respectively. Compressor  200  is connected to hose  205  to provide high pressure refrigerant fluid to condenser  206 . In this case, the compressor is shown to be powered by an internal combustion engine  220 . However, the compressor  200  could also be powered by an electric or hydraulic motor. Future technological improvements could, of course, provide alternatives to the compressor or its powering components without interfering with the concepts of this invention. 
   The HVAC system  300  is employed for maintaining the passenger compartment  12  within a desired temperature range and is supplied with A/C refrigerant fluid through high pressure hose  204  and an electrically controlled shut-off valve  207 . Hose  202  is used to return the heated refrigerant fluid to the compressor  200 . In this embodiment, the chiller  100  shares compressor  200  and condenser  206  with the HVAC system  300 . Accordingly, hoses  201  and  203  are shown connected in parallel to the compressor  200  with hoses  202  and  204  respectively. Hose  203  is routed from condenser  206  to shut-off valve  208  and to the evaporator core  120  to supply refrigerant fluid from the condenser  206 . Hose  201  is routed from the evaporator core  106  of the chiller  100  to compressor  200  to return the warmed fluid to the compressor  200 . 
   HVAC controller  250  is shown in a schematic of  FIG. 3  that provides a signal on line V 1  to activate and open valve  207 . Also, controller  250  sends an engagement signal to the Powertrain Control Module (PCM)  350  to turn on the compressor  200 . The PCM is of the type that is commonly used in automotive systems controls the compressor  200  on line C 1 , when required. The HVAC controller  250  may or may not contain a processor, pending on its level of complexity. The chiller control module  150  provides the necessary cooling functions to the chiller unit  100 . However, it is intended to be less complex than the HVAC controller  250  which provides both heated and cooled air (fresh or recirculated) to the passenger compartment on demand. While  FIG. 3  indicates that separate control modules are used for HVAC and the chiller control, this showing is for convenience. It is understood that a single control module could be designed to perform both functions, as well as other methods for arranging inputs and control lines. 
   The chiller control unit  150  receives inputs on its T 1  and T 2  lines from temperature sensors  124  and  126  located in the chiller air duct  110 . When switched on via switch  152  on the vehicle dash (or elsewhere), the controller  150  will send a signal to PCM  350  to engage the clutch  205  of compressor  200  with an output signal on line C 1 , and open the shut-off valve  208  with an output signal on line Vc. When engaged and powered, the compressor  200  will provide refrigerant fluid to the evaporator core  120  through the open valve  208 . The controller  150  also controls the speed of the variable speed fan  130  with an output signal on line Fc. In this embodiment, temperature sensors  124  and  126  provide temperature feedback to chiller control unit  150 . At least one temperature sensor is required to allow the controller to determine the settings for the fan speed as well as when to cause the compressor to be engaged and the shut-off valve  208  to be opened, to provide refrigerant fluid to the evaporator  120 . However, by using temperature feedback from both the supply and return ducts the controller can more precisely determine the temperature differential between supplied and returned air and make certain conclusions about the operation of the system. For instance, if one duct opening is fully blocked, the controller can sense the failure of the system to cool the localized volume over time and shut down the system to protect the elements. 
   In the foregoing discussion, it should be clear that the chiller unit  100  is controlled independently from the HVAC system  300 . This allows the vehicle occupants to turn the HVAC off and open the windows if so desired, while providing a chilled environment for the contents of the cargo storage area. 
   An alternative embodiment of the invention is shown in  FIG. 4 , wherein the air duct  410  is extended to provide cross-flow of cooled air through the localized volume. In this case, a duct portion  411  extends, below the floor of the storage area and joins with a duct portion  413  that is located adjacent the opposite wall. Duct portion  413  contains openings  412   a  and  412   b  which provide a path for the flow of return air to the system. With an evaporator core  420 , fan  430  and supply opening  414  located in duct  410 , the system can provide a more even cooling of the localized volume. The fan  430  may be located at any position within the air duct  410  or portions thereof where its function is deemed to be the most efficient. 
   Another alternative embodiment is shown in  FIG. 5 , wherein the embodiment shown in  FIG. 1  is modified to allow storage compartment cooling from the ceiling of the vehicle when the chiller function is not needed or the need is greatly reduced, such as when pets are located in the localized space. In this case, the chiller unit  500  includes an air duct  510  with a pair of openings  512  and  514  to remove and supply air to the localized volume. An evaporator core  520  is also contained within air duct  510  to refrigerate the air flowing therethrough. A variable speed fan  530  also is included within the air duct  510  to act as an air movement device. The fan  530  forces the air through the duct  510  and the evaporator core  520  as well as providing the supply and removal of cooled air to and from the localized volume. A duct portion  511  extends from the upper portion of duct  510  into the ceiling of the vehicle. Openings  515   a  and  515   b  are provided in the duct portion  511  to allow supply of refrigerated air to the larger cabin volume, when desired. A mode selection door  516  is located between the air duct opening  514  and the duct portion  511 . The mode selection door  516  may be placed in any selected position to regulate the amount of air that is distributed to the several supply openings. This allows the chiller unit to provide refrigerated air to the storage area, as in the first embodiment and to serve a more flexible function of providing additional cooling to the rear of the passenger compartment. 
   From the foregoing, it can be seen that there has been brought to the art a new and improved system for providing localized cooling to a predetermined storage volume of a vehicle with great flexibility to satisfy the desires and convenience of the vehicle users. It is to be understood that the preceding descriptions of the preferred embodiment and alternative embodiments are merely illustrative of some of the many specific embodiments that represent applications of the principles of the present invention. Clearly, other arrangements would be evident to those skilled in the art without departing from the scope of the invention as defined by the following claims.