Patent Publication Number: US-2020298671-A1

Title: Grill for transport refrigeration unit

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of European Patent Application No. 19305322.0, filed Mar. 18, 2019, the disclosure of which is incorporated herein by reference in its entirety. 
     BACKGROUND 
     Embodiments of the current disclosure relate generally to transport refrigeration units and, more particularly, to a grill of a transport refrigeration unit. 
     A typical transport refrigeration unit mounting on the front face of a tractor trailer unit includes a one piece, self-contained fully refrigerant charged, prewired, refrigerant/heating unit powered by a diesel engine. In such a design the evaporator section fits into a rectangular opening in the upper portion of the trailer front wall. When installed, the evaporator section is located inside the trailer; and the condensing section is outside at the front of the trailer. The condensing section consists of an engine-compressor drive package, condenser fan, condenser coil, radiator coil, control panel, relay module, refrigerant controls, piping, wiring and associated components. 
     Also supported by the structural framework is an outer cover which includes the necessary air inlet and outlet openings for air cooling of the condenser coil, and doors which may be opened to provide access to the interior of the unit for maintenance and service. 
     The air inlet for cooling of the condenser coil is provided by way of a grill located at the upper, front face of the cover. Typically, the grill is composed of a durable rigid plastic material, such as for example acrylonitrile butadiene styrene (ABS) material or polyethylene or polyolefin material, and is mounted to a surrounding support structure, commonly referred to as a surround assembly, that is mounted to the framework of the refrigeration unit. In conventional practice, the grill is mounted to the surround assembly by means of a plurality of threaded fasteners arranged in spaced relationship about the periphery of the grill. 
     BRIEF DESCRIPTION 
     According to one or more embodiments, a cover assembly of a transport refrigeration unity includes a surround assembly having a central opening and a grill positionable in overlapping relationship with the central opening. The grill includes a plurality of louver members and a plurality of openings is defined between the plurality of louver members. The plurality of openings is arranged in fluid communication with the central opening. The plurality of openings define a variable inlet area. 
     In addition to one or more of the features described above, or as an alternative, in further embodiments the plurality of louver members are movable between a first position and a second position. 
     In addition to one or more of the features described above, or as an alternative, in further embodiments each of the plurality of louver members is rotatable about a respective axis between the first position and the second position. 
     In addition to one or more of the features described above, or as an alternative, in further embodiments the inlet area is maximized when the plurality of louver members are in the first position. 
     In addition to one or more of the features described above, or as an alternative, in further embodiments the plurality of louver members extend generally perpendicular to a surface of the surround assembly when in the first position. 
     In addition to one or more of the features described above, or as an alternative, in further embodiments the inlet area is minimized when the plurality of louver members are in the second position. 
     In addition to one or more of the features described above, or as an alternative, in further embodiments the plurality of louver members extend generally parallel to a surface of the surround assembly when in the first position. 
     In addition to one or more of the features described above, or as an alternative, in further embodiments the plurality of openings are fully sealed when the plurality of louver members are in the second position. 
     In addition to one or more of the features described above, or as an alternative, in further embodiments between about 10% and 20% of the central opening is arranged in fluid communication with the plurality of openings when the plurality of louver members are in the second position. 
     In addition to one or more of the features described above, or as an alternative, in further embodiments the grill further comprises a central support and a first plurality of louver members extend from the central support in a first direction and a second plurality of louver members extend from the central support in a second direction. 
     In addition to one or more of the features described above, or as an alternative, in further embodiments comprising a control system including: an actuation mechanism coupled to at least one of the plurality of louver members and a controller operably coupled to the actuation mechanism. The controller is configured to communicate a movement command associated with the at least one of the plurality of louver members to the actuation mechanism. 
     According to another embodiment, a transport refrigeration unit including a condenser heat exchanger and a cover assembly in overlying relationship with the condenser heat exchanger. The cover assembly defines a variable inlet area through which air is provided to the condenser heat exchanger. 
     In addition to one or more of the features described above, or as an alternative, in further embodiments the inlet area is variable in response to a demand of the transport refrigeration unit. 
     In addition to one or more of the features described above, or as an alternative, in further embodiments the cover assembly includes a grill having a plurality of louver members, the plurality of louver members being movable to vary the inlet area. 
     According to yet another embodiment, a method of operating a transport refrigeration system includes providing a surround assembly having a central opening, providing a grill in overlapping relationship with the central opening, the grill including a plurality of louver members that define an inlet area, and varying the inlet area of the grill based on a demand of the transport refrigeration system. 
     In addition to one or more of the features described above, or as an alternative, in further embodiments varying the inlet area of the grill further comprises moving at least one of the plurality of louver members between a first position and a second position. 
     In addition to one or more of the features described above, or as an alternative, in further embodiments moving the at least one of the plurality of louver members includes operating an actuation mechanism coupled to the at least one of the plurality of louver members. 
     In addition to one or more of the features described above, or as an alternative, in further embodiments comprising communicating a commanded position of the at least one of the plurality of louver members from a controller to the actuation mechanism. 
     In addition to one or more of the features described above, or as an alternative, in further embodiments varying the inlet area of the grill further comprises moving the plurality of louver members toward an open position to increase the inlet area and an airflow provided to the transport refrigeration unit in response to an increase in demand. 
     In addition to one or more of the features described above, or as an alternative, in further embodiments varying the inlet area of the grill further comprises moving the plurality of louver members toward a closed position to decrease the inlet area and an airflow provided to the transport refrigeration unit in response to a decrease in demand. 
     Additional features and advantages are realized through the techniques of the embodiments herein. Other embodiments are described in detail herein and are considered a part of the claims. For a better understanding of the embodiments with the advantages and the features, refer to the description and to the drawings. 
    
    
     
       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  is a side view of an example of a transport refrigeration trailer; 
         FIG. 2  is a perspective view of an example of a transport refrigeration unit according to an embodiment; 
         FIG. 3A  is a front view of a grill of a cover assembly of a transport refrigeration unit in a first position according to an embodiment; 
         FIG. 3B  is a side view of the louver members of the cover assembly of  FIG. 3A  according to an embodiment; 
         FIG. 4A  is a front view of a grill of a cover assembly of a transport refrigeration unit in a second position according to an embodiment; 
         FIG. 4B  is a side view of the louver members of the cover assembly of  FIG. 4A  according to an embodiment; and 
         FIG. 5  is a schematic diagram of a control system of the transport refrigeration unit according to an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     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 FIGS. 
     With reference now to  FIG. 1 , an example of a transport refrigeration trailer  20  for transportation of various good is illustrated. The trailer  20  has a trailer body  22  including an internal “cargo area”  24  formed by thermally insulated walls including a top wall  26 , bottom wall  28 , front wall  30 , rear wall  32 , as well as side walls (not shown). To the extent that goods within the cargo area  24  need to be kept in an air conditioned environment, such as where the goods are perishable food items for example, the trailer  20  includes a refrigeration system. In the illustrated embodiment, a transport refrigeration unit (“TRU”)  34  including a refrigeration system is attached to a portion of the trailer body  22 , such as the front wall  30 . The TRU  34  is operable to draw heated air in from the cargo area  24 , to cool the heated air, and to exhaust the cooled air back into the cargo area  24 . 
     An example of a TRU  34  is illustrated in more detail in  FIG. 2 . For purposes of the present description the terms “roadside” and “curbside” will be used in describing various components of the refrigeration unit and its cover. As viewed in  FIG. 2 , the right hand side of the TRU  34  will be referred to as the roadside and the left hand side of the TRU  34  will be referred to as the curbside. 
     In the illustrated, non-limiting embodiment, the TRU  34  has a cover assembly  40  including a lower cover assembly  42  and an upper cover assembly  44 . The lower cover assembly  42  includes a curbside front door  46 , a curbside outer door  48 , a roadside front door  50 , and a roadside outer door  52 , all shown in their closed positions. The lower cover assembly  42  additionally includes side panels  54  and a bottom panel  56 . The curbside and roadside front doors  46 ,  50  are vertically hinged at their respective outer edges so as to swing outwardly to open to provide a large access opening at the front of the TRU  34 , thereby providing access to the inner structural components of the TRU  34 , as well as some of the components of the refrigeration system itself. 
     The curbside and roadside outer doors  48 ,  52  are mounted within the respective side panels  54  and vertically hinged at their respective rear edges such that they pivot open from front to back to provide additional access openings to the interior of the TRU  34  at the sides of the unit. Latches  58  are provided for latching and unlatching the roadside front door  50  and the roadside outer door  52 , respectively. The bottom panel  56  is attached to the lower cover assembly  42  for purposes of closure and to improve the aesthetics of the TRU  34 . 
     Attachment of the TRU  34  to the trailer  20  is carried out by connection of an outer peripheral planar structural steel framework designated generally by reference numeral  60 . It should be appreciated that this framework  60  is not normally visible when the unit is properly installed on a trailer  20 ; however for purposes of illustration, at least a portion of the structural framework is illustrated in  FIG. 2 . All of the component assemblies which define the outer cover of the TRU  34  are mounted to the various structural members of the framework  60 . 
     The upper cover assembly  44  includes a front grill  62  member and a relatively flexible support structure  64 , also referred to herein as the surround assembly, disposed in surrounding relationship therewith. The grill  62  is positioned in overlying relationship with a central opening  66  in the surround assembly  64  and the condenser heat exchanger located there behind (not shown). The grill  62  includes a plurality of openings  68  to facilitate air flow for efficient heat transfer to cool the condenser coil (not shown) of the TRU  34 . The grill  62  may be affixed to the surround assembly  64  in any suitable manner, such as with fasteners, or via a snap fit connection for example. 
     A top panel  70  may be attached to the upper cover assembly  44  of the TRU  34  for purposes of closure and to improve the aesthetic of the TRU  34 . It will be appreciated that the door, panel, surround assembly  64  and grill  62  are designed to cooperate to fully enclose the refrigeration system of the TRU  34  to provide protection from the environment and road hazards and to aerodynamically and aesthetically enhance the TRU  34 . 
     With reference now to  FIGS. 3-4 , an example of the front grill  62  is shown in more detail. As illustrated, the front grill  62  is shown having a generally rectangular or trapezoidal shape. In addition, the grill  62  is slightly curved from front to back, so as to wrap around the front face of the TRU  34  as shown. However, it should be understood that a grill  62  having any shape and configuration is contemplated herein. 
     The grill  62  includes one or more louver members  72  arranged in an overlapping relationship with the surround assembly  64 . The louver members  72  may be made from any suitable material including but not limited to plastic and metal for example. In addition, in an embodiment, a noise deadening material  74  (see  FIG. 3B ), for example foam, may be mounted to a surface of the louver members  72  generally adjacent the central opening  66 . In the illustrated, non-limiting embodiment, the grill  62  includes a plurality of horizontally disposed and vertically spaced louver members  72 . The plurality of louver members  72  may be substantially identical, or alternatively, may vary, such as based on the position of the louver members  72  relative to the surround assembly  64  for example. In an embodiment, the one or more louver members  72  may extend across a full width of the central opening  66  of the surround assembly  64 . However, in other embodiments, such as where the condenser unit (not shown) has two air movement devices (i.e. condenser fans)  71 , at least a portion of the grill  62  may include a central support  76  and two distinct sets of louver members  72 . As shown, a first set of louver members  72   a  extends from the central support  76  in a first direction and a second set of louver members  72   b  extends from the central support  76  in a second, opposite direction. Together, the first and second set of louver members  72   a ,  72   b  cooperate to span the central opening  66  of the surround assembly  64 . In such embodiments, the central support  76  may be integrally formed with, or alternatively, may be separate from the surround assembly  64 . 
     Although the first and second sets of louver members  72   a ,  72   b  are substantially identical, and more specifically, symmetrical about a plane defined by and extending through the central support  76 , embodiments where a configuration of the sets of louver members  72   a ,  72   b  varies are also within the scope of the disclosure. Further, it should be understood that embodiments including more than two sets of louver members  72  arranged to span the central opening  66  of the surround assembly  64  are also within contemplated herein. 
     In an embodiment, the one or more louver members  72  of the grill  62  are movable between a first position ( FIGS. 3A, 3B ) and a second position ( FIGS. 4A, 4B ). For example, the one or more louver members  72  may be pivotally mounted such that each of the louver members  72  is configured to rotate about a respective axis X, out of a plane of the surround assembly  64 , between the first position and the second position. However, other movement of the louver members  72  is also within the scope of the disclosure. Because the plurality of openings  68  are defined between vertically adjacent louver members  72 , the height of each opening  68 , and therefore the cross-sectional area of each opening  68 , will vary as the louver members  72  transition between the first position and the second position. The plurality of openings  68  may be considered to define a condenser inlet area arranged in fluid communication with the central opening  66 . Accordingly, the condenser inlet area is variable by adjusting the position of the louver members  72 . 
     In an embodiment, the one or more louver members  72  are oriented substantially perpendicular to the surround assembly  64 , and parallel to rotational axis of the condenser fans in the first position. Accordingly, when the one or more louver members  72  are in the first position, the size of the openings  68  defined there between is configured to maximize the air flow through the central opening  66  to an adjacent condenser fan  71 . It should be understood that maximum cross-sectional area defined by the openings  68  is dependent on the total number of louver members  72  and the thickness of the louver members  72 . 
     In the second position, the one or more louver members  72  are oriented at a non-perpendicular angle relative to the surround assembly  64 . In an embodiment, the one or more louver members  72  may be oriented substantially parallel to the surround assembly  64  and perpendicular to the axis of the condenser fans  71  when in the second position. Depending on the spacing of the louver members  72 , when in the second position, the one or more louver members  72  may substantially seal the plurality of openings  68  to prevent a fluid flow through the central opening  66  to the condenser fans  71 . However, in another embodiment, in the second position, between about 10%-20% of the cross-sectional area of the central opening  66  is exposed through the openings  68  defined by the louver members  72 . 
     It should be understood that the first and second positions described herein are intended as an example only, and any orientation of the louver members  72  may be defined as the first and second position. Further, it should be understood that the plurality of louver members  72  may be arranged at any intermediate position between the first position and the second position. 
     With reference now to  FIG. 5 , the TRU  34  additionally includes a control system  80  including one or more actuation mechanisms  82 , such as an electrical motor or actuator for example, for moving the louver members  72  between the first position and the second position. Power to operate the one or more actuation mechanisms  82  may be supplied from another portion of the trailer  20 , such as a generator, illustrated schematically at  84 . In an embodiment, the plurality of louver members  72  of the grill  62 , or alternatively, the plurality of louver members  72  within a set is connected to a single actuation mechanism  82 . As a result, the actuation mechanism  82  is operable to move each of the plurality of louver members  72  about a respective axis X, in unison. Alternatively, the TRU  34  may include a plurality of actuation mechanisms  82 , such that the position of the louver members  72  are adjusted in groups, or alternatively, individually. Accordingly, the position of the plurality of the louver members  72  may be adjusted non-uniformly. 
     The control system  80  further includes a controller  86  operably coupled to the one or more actuation mechanisms  82 . The controller  86  may generate and send a command to an actuation mechanism  82  indicating a desired movement and/or location of the louver members  72  associated therewith. The controller  86  may be the same controller used to control operation of the refrigeration system, or alternatively, may be different. In an embodiment, the controller is configured to adjust the position of the louver members  72  in response to a cooling demand of the TRU  34 . For example, in high speed operation, when maximum cooling capacity of the TRU  34  is needed, the louver members  72  may be rotated to the first, fully open position, to maximize the airflow provided to the condenser unit. Maximizing the cross-sectional area of the openings  68  optimizes the cooling performance of the TRU  34 . Similarly, during lower speed operation, the louver members  72  may be rotated towards the second position to reduce the cross-sectional area of the openings  68  and therefore the air flow provided to the condenser fans  71 . By reducing the size of the openings  68 , the noise generated by the air flow is reduced. 
     In an embodiment, one or more sensors S may be associated with the grill  62  or the surround assembly  64  to monitor an actual position of the louver members  72 . The sensor information may be communicated to the controller  86  where it is compared with the commanded position of the louver members  72 , for example to determine an error value. In embodiments where the error value exceeds a predetermined threshold, the controller  86  may issue a corrected command intended to compensate for the discrepancy between the actual and commanded position. 
     A TRU  34  as illustrated and described herein has a reduced noise output compared to existing systems. Further, the grill  62  may be adapted for use with existing systems without having to adjust the position of the condenser fans  71 . 
     All of the component assemblies which define the outer cover of the refrigeration unit are mounted to the various structural components. In the illustrated, non-limiting embodiment, the TRU includes a curbside front door and a roadside front door. In their closed positions, the curbside front door and the roadside front door cover inner structural components of the unit as well as some of the refrigeration unit itself. These TRU additionally includes a curbside outer door and a roadside outer door. Each of the doors forming the lower portion of the cover are made from a tough, light weight composite material designed to resist rust, denting, warping, fading, or peeling of their outer finish. 
     In the illustrated, non-limiting embodiment, the front doors are vertically hinged at their respective outer edges to provide a large access opening at the front of the unit. The side doors are vertically hinged at their rear edges such that the pivot open from front to back. Latches are provided for latching and unlatching the front roadside door and the side roadside door, respectively. 
     Aspects of the embodiments are described herein with reference to flowchart illustrations, schematics, and/or block diagrams of methods, apparatus, and/or systems according to embodiments. Further, the descriptions of the various embodiments have been presented for purposes of illustration but are not intended to be exhaustive or limited to the embodiments disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The terminology used herein was chosen to best explain the principles of the embodiments, the practical application or technical improvement over technologies found in the marketplace, or to enable others of ordinary skill in the art to understand the embodiments disclosed herein. 
     The terminology used herein is for describing particular embodiments only and is not intended to be limiting. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one more other features, integers, steps, operations, element components, and/or groups thereof. 
     While the preferred embodiment has been described, it will be understood that those skilled in the art, both now and in the future, may make various improvements and enhancements which fall within the scope of the claims which follow. These claims should be construed to maintain the proper protection.