Abstract:
A method ( 80 ) of operating a refrigeration system ( 48 ) for a refrigerated mobile cargo container ( 2 ) includes sensing a temperature outside of the refrigerated mobile cargo container ( 2 ), detecting a position of a door ( 16, 18 ) on the refrigerated mobile cargo container ( 2 ), and deactivating the refrigeration system ( 48 ) if the door ( 16, 18 ) is open and the temperature outside of the refrigerated mobile cargo container ( 2 ) is less than a predetermined value.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a National Stage Application of PCT Application No. PCT/US11/034745, filed May 2, 2011, which claims priority of U.S. Provisional Application Ser. No. 61/346,315, filed May 19, 2010, the disclosure of which is incorporated by reference herein in its entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     Exemplary embodiments pertain to the art of refrigeration systems and, more particularly, to a refrigeration control system for a mobile cargo container. 
     Currently, many manufacturers of goods that require refrigeration rely upon carriers to supply refrigerated mobile cargo containers including a refrigeration system to transport the goods to market. The refrigerated mobile cargo containers are parked at the manufacturer and loaded with the goods. Generally, it can take several hours to fully load a refrigerated mobile cargo container before it is ready for shipment. While being loaded, doors on the refrigerated mobile cargo container typically remain open. As such, manufacturers typically require that the refrigeration system remain operational while the refrigerated mobile cargo container is being loaded. 
     BRIEF DESCRIPTION OF THE INVENTION 
     Also disclosed is a refrigerated mobile cargo container including a door, a door position sensor configured and disposed to detect a position of the door, a temperature sensor configured and disposed to detect a temperature outside of the refrigerated mobile cargo container, a refrigeration system selectively operable to condition an interior storage zone of the refrigerated mobile cargo container, and a controller operatively coupled to the door position sensor, temperature sensor and the refrigeration system. The controller selectively deactivating the refrigeration system based on inputs from the door position sensor and the temperature sensor. 
     Also disclosed is a refrigerated mobile cargo container including a door, a door position sensor configured and disposed to detect a position of the door, a temperature sensor configured and disposed to detect a temperature outside of the refrigerated mobile cargo container, a refrigeration system selectively operable to condition an interior storage zone of the refrigerated mobile cargo container, and a controller operatively coupled to the door position sensor, temperature sensor and the refrigeration system. The controller selectively activating the refrigeration system based on inputs from the door position sensor and the temperature sensor. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The following descriptions should not be considered limiting in any way. With reference to the accompanying drawings, like elements are numbered alike: 
         FIG. 1  depicts a refrigerated mobile cargo container in accordance with an exemplary embodiment; and 
         FIG. 2  depicts a flow diagram illustrating a method of operating a refrigeration system for the refrigerated mobile cargo container of  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     A detailed description of one or more embodiments of the disclosed apparatus and method are presented herein by way of exemplification and not limitation with reference to the Figures. 
     With reference to  FIG. 1 , a refrigerated mobile cargo container in accordance with an exemplary embodiment is indicated generally at  2 . Refrigerated mobile cargo container  2  includes a body  4  including a plurality of walls  6 - 8  that define an interior storage zone  10  having a floor  12  and an opening  14 . As will be discussed more fully below, interior storage zone  10  is temperature controlled to preserve goods stored therein. Refrigerated mobile cargo container  2  is also shown to include doors  16  and  18  as well as wheels  20  and forward supports  22 . 
     In accordance with an exemplary embodiment, refrigerated mobile cargo container  2  includes a controller  40  having a processor or CPU  42  and a memory  44 . Controller  40  is operatively connected to a refrigeration system  48  that is configured to condition internal temperatures of interior storage zone  10 . Controller  40  is also operatively connected to a temperature sensor  50  and a door position sensor  52 . Temperature sensor  50  is configured to detect ambient temperatures, or temperatures outside of refrigerated mobile cargo container  2 . Door position sensor  52  is configured to detect a position of doors  16  and  18 . Door position sensor  52  signals controller  40  when doors  16  and/or  18  are in an open position and a closed position. Controller  40  is also shown to be coupled to an input device  54  that is configured to communicate with memory  44 . As will be detailed more fully below, input device  54  enables a user to select various options for operating refrigeration system  48 . 
     Reference will now be made to  FIG. 2  in describing a method  80  of controlling refrigeration system  48 . Initially, a determination is made in block  82  whether user inputs/preferences are received through input device  54 . If no inputs are received, default values are set in block  84  and a determination is made in block  86  whether door  16  and/or door  18  is open. If user input is received, any selected preferences are stored in memory  44  and door position determination is made in block  86 . If door  16  and/or door  18  is sensed to be open, temperature sensor  50  is polled to determine whether the ambient or outside temperature is below either a default value or a user selected value stored in memory  44  as indicated in block  88 . If the ambient temperature is above the default value or user selected value, a determination is made in block  89  whether controller  40  is programmed for low speed operation. If not programmed for low speed operation, controller  40  activates refrigeration system  48  in one of a high speed operation or a low speed operation, as indicated in block  90 , dependent upon cooling demand. If programmed for low speed operation, controller  40  activates refrigeration system  48  at low speed as indicated in block  91 . 
     If in block  88  it is determined that the ambient temperature is below the default or user selected value, a determination is made in block  92  whether controller  40  is programmed to operate refrigeration system  48  in a low speed mode. If controller  40  is not programmed to operate refrigeration system  48  in the low speed mode, refrigeration system  48  is shut down as indicated in block  94 . If, however, controller  40  is programmed to operate refrigeration system  48  in the low speed mode, refrigeration system  48  is either powered down to low speed operation, or low speed operation is continued if already established as indicated in block  96 . In addition to the above, controller  40  is programmed for various delays to avoid repeated cycling of refrigeration system  48  in the event door  16  and/or  18  is repeatedly opened and closed during a short time interval. 
     At this point it should be understood that the exemplary embodiments provide a system for operating a refrigeration system for a refrigerated mobile cargo container to minimize fuel use and to lower emissions. Refrigeration systems are operated continuously during loading to ensure any goods stored in the interior storage zone remain at or near a desired temperature. However, this continued operation may be costly and result in high emissions as loading may take several hours. Other prior art systems trigger changes in operating parameters of the refrigeration system based on ambient temperature. For example, ambient temperature sensing is used to control operational speed of a compressor. When ambient temperatures are low, the compressor need not work at full capacity. However, during loading, when the doors are open, such systems run continuously, usually at high speed. Continuous operation, regardless of the speed, leads to higher emissions and increased operational costs. The exemplary embodiments cease operation of the refrigeration system during periods when ambient temperatures are at or below desired levels and activate the refrigeration system when ambient temperatures are above the desired levels. In this manner, fuel costs and emissions associated with operation of the refrigeration system during loading of the refrigerated mobile cargo container are minimized. 
     While the invention has been described with reference to an exemplary embodiment or embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the claims.