Patent Publication Number: US-2016231043-A1

Title: Air intake for refrigerated container assembly

Description:
BACKGROUND OF THE INVENTION 
     The subject matter disclosed herein relates to refrigeration systems. More specifically, the subject matter disclosed herein relates to refrigeration of containers utilized to store and ship cargo. 
     A typical refrigerated cargo container or refrigerated truck trailer, such as those utilized to transport a cargo via sea, rail or road, is a container modified to include a refrigeration unit located at one end of the container. The refrigeration unit includes a compressor, condenser, expansion valve and evaporator serially connected by refrigerant lines in a closed refrigerant circuit in accord with known refrigerant vapor compression cycles. A power unit, including an engine, drives the compressor of the refrigeration unit, and is typically diesel powered, or in other applications natural gas powered. In many truck/trailer transport refrigeration systems, the compressor is driven by the engine shaft either through a belt drive or by a mechanical shaft-to-shaft link. In other systems, the engine drives a generator that generates electrical power, which in turn drives the compressor. 
     Typically, air intakes for the refrigeration unit engine are located directly below the refrigeration unit. The air intakes are constructed of molded rubber or rubber-like materials that are costly to manufacture, which are then assembled to the container. Hoses are fitted to the air intakes to convey the air from the air intakes to the engine. While such a position of the air intakes is good for preventing water ingress into the air intakes, the air flowed into the intake can have an undesired high temperature, when compared air flowing along the side of the container or over the top of the container. The air at the bottom of the container is typically warmer due to radiant and convective heating from the pavement and from the tractor engine. Additionally, the intake air may be inadvertently heated by being routed past the refrigeration unit condenser, and the heated air flowing off of the condenser. 
     BRIEF DESCRIPTION OF THE INVENTION 
     In one embodiment, a refrigerated transportation cargo container includes a transportation cargo container and a refrigeration unit located at an end of the transportation cargo container to provide a flow of supply air for the transportation cargo container. The refrigeration unit includes a compressor and an engine operably connected to the compressor to drive the compressor. An engine air intake is located at a top wall of the cargo container to direct engine intake air from outside the cargo container through the engine air intake, and an air channel extends from the engine air intake to the engine. 
     In another embodiment, a method of operating a refrigeration unit for a refrigerated transportation cargo container includes operably connecting an engine to a compressor of the refrigeration unit and locating an engine air intake at a top wall of the cargo container. A flow of engine intake air is directed downwardly from outside of the cargo container and through the engine air intake to the engine, thereby proving the flow of engine air for engine operation. 
     These and other advantages and features will become more apparent from the following description taken in conjunction with the drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The subject matter, which is regarded as the invention, is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The foregoing and other features, and advantages of the invention are apparent from the following detailed description taken in conjunction with the accompanying drawings in which: 
         FIG. 1  is a schematic illustration of an embodiment of a refrigerated transportation cargo container; 
         FIG. 2  is a schematic illustration of an embodiment of a refrigeration unit for a refrigerated transportation cargo container; 
         FIG. 3  is a cross-sectional view of an embodiment of an engine air passage for a refrigeration unit of a refrigerated transportation cargo container; 
         FIG. 4  is another cross-sectional view of an embodiment of an engine air passage for a refrigeration unit of a refrigerated transportation cargo container; 
         FIG. 5  is a cross-sectional view of another embodiment of an engine air passage for a refrigeration unit of a refrigerated transportation cargo container; and 
         FIG. 6  is a cross-sectional view of yet another embodiment of an engine air passage for a refrigeration unit of a refrigerated transportation cargo container. 
     
    
    
     The detailed description explains embodiments of the invention, together with advantages and features, by way of example with reference to the drawing. 
     DETAILED DESCRIPTION OF THE INVENTION 
     Shown in  FIG. 1  is an embodiment of a refrigerated cargo container  10 . The cargo container  10  is formed into a generally rectangular construction, with a top wall  12 , a directly opposed bottom wall  14 , opposed side walls  16  and a front wall  18 . The cargo container  10  further includes a door or doors (not shown) at a rear wall  20 , opposite the front wall  18 . The cargo container  10  is configured to maintain a cargo  22  located inside the cargo container  10  at a selected temperature through the use of a refrigeration unit  24  located at the container  10 . The cargo container  10  is mobile and is utilized to transport the cargo  22  via, for example, a truck, a train or a ship. The refrigeration unit  24  is located at the front wall  18 , and includes a compressor  26 , a condenser  28 , an expansion valve  30 , an evaporator  32  and an evaporator fan  34  (shown in  FIG. 2 ). The compressor  26  is operably connected to an engine  36  which drives the compressor  26 . In some embodiments, the engine  36  is diesel powered. In other embodiments, the engine is powered by another fuel such as natural gas. Further, the engine is connected to the compressor in one of several ways, such as a direct shaft drive, a belt drive, one or more clutches, or via an electrical generator. Referring to  FIG. 2 , return airflow  38  flows into the refrigeration unit  24  from the cargo container  10  through a refrigeration unit inlet  60 , and across the evaporator  32  via the evaporator fan  34 , thus cooling the return airflow  38  to a selected temperature. The cooled return airflow  38 , now referred to as supply airflow  40  is then supplied into the container  10  through a refrigeration unit outlet  42 , which in some embodiments is located near the top wall  12  of the cargo container  10 . The supply air  40  cools the cargo  22  in the cargo container  10 . It is to be appreciated that the refrigeration unit  24  can further be operated in reverse to warm the cargo container  10  when, for example, the outside temperature is very low. 
     The evaporator  32  and evaporator fan  34  are segregated from the remaining components by an inner panel, or POD  48  to reduce undesired heating of the evaporator  32  and return airflow  38  by radiant heat from, for example, the condenser  28  and the engine  36 . The POD  48  is formed from, for example, a sheet metal forming or molding process and is secured to the front wall  18  of the container  10 . 
     Referring now to  FIG. 3 , an airflow channel  50  is formed between the POD  48  and the front wall  18  of the container  10 , laterally adjacent to the evaporator  32 . Referring now to  FIG. 4 , an air intake  54  located at the top wall  12  of the cargo container directs engine intake air  52  from outside the cargo container  10  into the airflow channel  50  and toward the engine  36  for operation thereof. The airflow channel  50  may be in the form of a passage bounded by the POD  48  and the front wall  18 , or may be a tubular structure formed in the POD  48 , as shown in  FIG. 5 . Further, as shown in  FIG. 6 , a tube  56  may be extended through the airflow channel  50  to direct the intake air  52  to the engine  36 . In some embodiments, the POD  48  includes a feature to prevent water from entering the air intake  54 , such as an extension  60  angled over the air intake opening such as shown in  FIG. 4  to prevent water ingress into the air intake  54 , while still allowing sufficient airflow into the air intake  54 . Alternatively or additionally, other elements, such as an air/water separator (not shown) may be positioned in the airflow channel  50  to separate water from the intake air  52  before the intake air reaches the engine  36 . 
     Positioning the air intake  54  at the top wall  12  of the container  10  and utilizing the POD  48  to direct the intake air  52  toward the engine  36  has numerous advantages over refrigeration units  24  with air intakes at a bottom wall of the container. Further, in some embodiments, flowing the intake air  52  via the POD  48  past the evaporator  32  results in cooling of the intake air  52 . The resulting intake air  52  is cleaner and cooler than that from the bottom wall, as there is reduced radiant and convective heating of the intake air  52 . Further, by utilizing the airflow channel  50  formed by the POD  48 , a length of hose necessary to direct the intake air  52  into the engine is reduced or eliminated, thereby reducing cost and complexity. Further, the cleaner and cooler intake air  52  improves engine  36  performance, especially given the trend toward downsizing and/or turbocharging engines for container use to improve fuel efficiency. 
     While the invention has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the invention is not limited to such disclosed embodiments. Rather, the invention can be modified to incorporate any number of variations, alterations, substitutions or equivalent arrangements not heretofore described, but which are commensurate with the spirit and scope of the invention. Additionally, while various embodiments of the invention have been described, it is to be understood that aspects of the invention may include only some of the described embodiments. Accordingly, the invention is not to be seen as limited by the foregoing description, but is only limited by the scope of the appended claims.