Abstract:
A heat exchanger system for an agricultural vehicle. The heat exchanger system has at least two separate heat exchanger assemblies, where an adjustable baffle is used to vary the airflow between the heat exchanger assemblies, accordingly varying the cooling effect of the assemblies, based on system requirements. The adjustable baffle may be arranged to restrict or block at least a portion of a heat exchanger to reduce airflow through the exchanger, to provide a flow bypass of an exchanger, and/or to proportionally adjust the airflow through a pair of heat exchangers provided as part of a single heat exchanger assembly.

Description:
BACKGROUND OF THE INVENTION 
     Field of the Invention 
       [0001]    The present invention relates to a heat exchanger system for a vehicle, in particular a heat exchanger system having more than one heat exchanger assembly. 
       Description of Related Art 
       [0002]    In general, a heat exchanger transfers a heat from a relatively high temperature fluid to a relatively low temperature fluid. Heat exchangers are commonly used in vehicles, as part of engine cooling systems, HVAC systems, etc., where atmospheric air is drawn through a radiator to provide a cooling of the working fluid of the heat exchanger. 
         [0003]    In some vehicles, e.g. agricultural tractors, a heat exchanger system may comprise a number of different heat exchangers, e.g. a first heat exchanger as part of an engine cooling system, and a second heat exchanger as part of an auxiliary cooling circuit, e.g. for oil cooling, HVAC applications, etc. In a space-saving effort, such separate heat exchangers may be provided in series with a fan, such that the airflow drawn by the fan is conveyed through both heat exchangers in series. However, such a series arrangement of heat exchangers does not allow for modification of the cooling effect provided between the different heat exchangers, and does not account for disparities in the required cooling levels of the separate heat exchangers. Such variation between the cooling requirements of the heat exchangers can lead to inefficient operation of the separate systems, as the different heat exchangers may be exposed to excessive or inadequate cooling levels, based on the requirements of the entire heat exchanger assembly as a whole. 
         [0004]    An example of a prior art heat exchanger system having an adjustable flow guiding device is provided in DE 102010000969 A1. 
         [0005]    It is an object of the invention to provide a heat exchanger system having improved efficiency. 
       SUMMARY OF THE INVENTION 
       [0006]    Accordingly, there is provided a heat exchanger system for a vehicle, the assembly comprising: 
         [0007]    a first heat exchanger assembly; 
         [0008]    a second heat exchanger assembly located downstream of said first heat exchanger assembly; and 
         [0009]    at least one baffle arranged between the first heat exchanger assembly and the second heat exchanger assembly, 
         [0010]    wherein said at least one baffle is adjustable to provide for variation of airflow between said first heat exchanger assembly and said second heat exchanger assembly. 
         [0011]    The baffle is arranged to adjust the airflow between the first and second heat exchangers, based on the requirements of the heat exchangers. Accordingly, the exchange of energy provided by the heat exchangers can be varied based on the requirements of a vehicle engine and/or the exchangers themselves. Such an adjustable system allows for more efficient operation of the vehicle, as the performance of the heat exchanger system can be more accurately adjusted to take into consideration vehicle systems requirements. An example of such an efficiency improvement can include greater engine and transmission efficiency, due to a decrease in the warming-up time for the vehicle engine. 
         [0012]    At least one of said first and second heat exchanger assemblies is provided as a plurality of separate heat exchanger subsections, wherein said at least one baffle is adjustable to control airflow to or from said separate heat exchanger subsections. 
         [0013]    The heat exchanger assemblies may comprise a number of separate subsections, which can be linked with different subsections of a greater engine cooling system, e.g. different cooling circuits linked with different subsystems of the vehicle. The different subsystems may comprise a transmission oil cooling circuit, an auxiliary oil cooling circuit, a fuel cooler, a condenser for a HVAC system, a front PTO cooler, etc. The at least one baffle may be used to prioritise flow through one of the heat exchanger subsections of an assembly over flow through the other subsections, for example based on increased cooling requirements for that particular heat exchanger subsection. 
         [0014]    Preferably, said at least one baffle is provided as a hinged member. Additionally or alternatively, said at least one baffle is provided with a linear actuator, arranged to selectively advance and retract said at least one baffle. Additionally or alternatively, said at least one baffle may comprise a telescopic member. 
         [0015]    By hinging and/or linearly adjusting the baffle, a flow path defined by the baffle between the heat exchangers can be easily adjusted in shape and/or flow volume. 
         [0016]    Preferably, said first and second heat exchanger assembly comprises a liquid coolant radiator and an air radiator, e.g. for intake air. The liquid coolant may comprise water or a mixture of water and antifreeze, e.g. ethylene glycol or propylene glycol. 
         [0017]    In one aspect, said at least one baffle is actuable between a first position and a second position, wherein 
         [0018]    in said first position, said at least one baffle is arranged to direct an output airflow from said first heat exchanger assembly as an input airflow to said second heat exchanger assembly; 
         [0019]    in said second position, said at least one baffle is arranged to direct at least a portion of the output airflow from said first heat exchanger assembly to bypass said second heat exchanger assembly. 
         [0020]    By providing a selectable bypass route for the second heat exchanger, the pressure drop across the second heat exchanger is reduced. Such a reduction in the pressure drop can act to reduce the fan consumption of the second heat exchanger, and accordingly of the entire heat exchanger system. 
         [0021]    In a further aspect, the heat exchanger system comprises an additional baffle arranged upstream of said first heat exchanger assembly, wherein said additional baffle is adjustable to provide for variation of airflow into said first heat exchanger assembly. 
         [0022]    The use of an additional baffle upstream of the first heat exchanger assembly allows for the control of the input airflow to the greater heat exchanger system. Such an additional baffle may be hingedly mounted and/or provided with a linear actuator to adjust the baffle position. 
         [0023]    Preferably, at least one of said first and second heat exchanger assemblies comprises a plurality of heat exchangers, wherein said at least one baffle is adjustable to vary the proportion of airflow through the respective heat exchangers of said plurality. 
         [0024]    The baffle may be variable to control the proportion of airflow, e.g. by adjusting an angular position of a hinged baffle or flap, to provide for an increased proportion of airflow through a first heat exchanger relative to a second heat exchanger of an assembly. 
         [0025]    Preferably, the heat exchanger system comprises at least one fan arranged in series with said first and second heat exchanger assemblies, said at least one fan arranged to cause air to be drawn through or blown into the heat exchanger assemblies of the heat exchanger system. 
         [0026]    The fan may be provided upstream or downstream of the heat exchanger assemblies. 
         [0027]    Preferably, said at least one baffle is arranged to selectively cover at least a portion of said second heat exchanger assembly, to prevent airflow through the portion of the second heat exchanger assembly. 
         [0028]    There is also provided an agricultural vehicle, preferably an agricultural tractor, having a heat exchanger system as described above. 
         [0029]    In a preferred embodiment, there is provided an agricultural vehicle comprising: 
         [0030]    an engine; 
         [0031]    an engine control unit (ECU) arranged to adjust engine performance based on sensor inputs; and 
         [0032]    a heat exchanger system as described above coupled to said engine, wherein said ECU is operable to adjust the at least one baffle of said heat exchanger system based on sensor inputs received by said ECU. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0033]    Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: 
           [0034]      FIG. 1  is a view of an agricultural tractor; 
           [0035]      FIG. 2  illustrates a heat exchanger system for a vehicle; 
           [0036]      FIG. 3  illustrates a heat exchanger system for a vehicle according to a first embodiment of the invention; 
           [0037]      FIGS. 4 and 5  illustrate a heat exchanger system for a vehicle according to a second embodiment of the invention; and 
           [0038]      FIGS. 6 and 7  illustrate a heat exchanger system for a vehicle according to a third embodiment of the invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0039]    The drawings presented herein are not meant to be actual views of any particular heat exchanger system, but are merely idealised representations that are employed to describe embodiments of the present disclosure. The drawings presented herein are not necessarily drawn to scale. Additionally, elements common between drawings may retain the same numerals. 
         [0040]    An agricultural tractor  10  is illustrated in  FIG. 1 . The tractor  10  comprises front wheels  12 , rear wheels  14 , an engine section  16  and a cab section  18 . The engine section  16  comprises a tractor engine  20  and a cooling system  22  located adjacent to the engine  20 . 
         [0041]    The cooling system  22  may comprise a heat exchanger system, as indicated at  24  in  FIG. 2 . The heat exchanger system  24  generally comprises a first heat exchanger assembly  26  and a second heat exchanger assembly  28 , the second heat exchanger assembly  28  arranged downstream of the first heat exchanger assembly  26  along a flow path. The direction of the flow path is indicated by arrow A. The first and second heat exchanger assemblies  26 , 28  may be provided as part of separate heat exchanger subsystems (not shown) for use in the agricultural tractor. For example, the first heat exchanger assembly  26  may be provided as a cooler for transmission oil, while the second heat exchanger assembly  28  may be provided as a radiator for an engine cooling system. Other possible subsystems may include a hydraulic oil cooling system, a HVAC system, etc. 
         [0042]    A fan  30  is arranged at the end of the flow path, downstream of the first and second heat exchanger assemblies  26 , 28 . A fan shroud or duct assembly  32  is used to define the boundaries of the flow path between the heat exchanger assemblies  26 , 28  and the fan  30 . 
         [0043]    The first and second heat exchanger assemblies  26 , 28  generally comprise a radiator or other suitable device to receive a working fluid, e.g. water, engine coolant fluid, transmission oil, hydraulic oil, etc. The fan  30  is arranged to draw in air, indicated by arrows B, through the heat exchanger assemblies  26 , 28 , to cool the contained working fluid. 
         [0044]    As the cooling requirements of the first and second heat exchanger assemblies  26 , 28  may very independently of each other, it is desirable to be able to separately control the cooling effect achieved by the heat exchanger assemblies  26 , 28 . It may be desirable to reduce the exposure of the second heat exchanger assembly  28  in order to warm a contained fluid. For example, it may be desirable to warm a portion of transmission oil, in order to increase efficiency of the system, e.g. after start-up of a vehicle. 
         [0045]    In  FIG. 3 , the heat exchanger system  24  comprises an adjustable baffle  34   a . The baffle  34   a  is arranged between the first and second heat exchanger assemblies  26 , 28 , and is operable to be advanced or retracted into the space between the heat exchanger assemblies  26 , 28 , as indicated by arrow B. The baffle  34   a  presents an adjustable barrier in the flow path of the heat exchanger system  24 , such that the flow path between the first heat exchanger assembly  26  and the second heat exchanger assembly  28  is limited by the position of the baffle  34   a  and the walls of the fan shroud  32 . 
         [0046]    The baffle  34   a  may comprise a plate member coupled with a linear actuator arranged to move the baffle  34   a  in a linear motion. Additionally or alternatively, the baffle  34   a  may comprise a telescopic plate member, a roller shutter system, an aperture twist shutter, or any apparatus suitable to provide for an adjustable barrier height or dimensions. It will be understood that the fan shroud  32  may comprise an aperture  36  arranged to receive the baffle  34   a , to allow for the relative motion of the baffle  34   a  into and out of the flow path of the heat exchanger system  24 . Alternatively, the baffle  34   a  may be fully retained within the interior of the heat exchanger system  34   a , even when fully retracted, e.g. through use of a roller shutter system. 
         [0047]    By adjustment of the height of the baffle  34   a  in the flow path, while air may be drawn through the entire area of the first heat exchanger assembly  26 , airflow may be restricted to pass through only a portion of the area of the second heat exchanger assembly  28 , based on how much the adjustable baffle  34   a  is extended to block or cover the second heat exchanger assembly  28 . 
         [0048]    By blocking a portion of the exchanger, the pressure drop across the fan is increased, which can lead to a corresponding increase in fan consumption. In one aspect, in order to decrease the quantity of energy exchanged, fan speed can be reduced, thereby reducing fan energy consumption. Alternatively, if the fan speed must be high for some portion of the assembly, the baffle is arranged to reduce the airflow in other areas of the system. 
         [0049]    As the cooling effects of the different exchangers of the system can be adjusted independently, the overall vehicle efficiency can be improved, due to a faster response time for separate vehicle systems to reach their optimal temperatures. 
         [0050]    A further embodiment of the invention is illustrated in  FIGS. 4 and 5 . In this embodiment, the second heat exchanger assembly  28  is of reduced height relative to the first heat exchanger assembly  26 . A bypass baffle  34   b  is arranged in the heat exchanger system  24 , to direct airflow along a flow path between the heat exchanger assemblies  26 , 28 . The bypass baffle  34   b  is hingedly mounted in the heat exchanger system  24 , arranged to pivot between a closed position, shown in  FIG. 4 , and an open position, shown in  FIG. 5 . 
         [0051]    In the closed position shown in  FIG. 4 , the bypass baffle  34   b  is arranged such that substantially the entire airflow through the first heat exchanger assembly  26  is directed by the baffle to flow through the second heat exchanger assembly  28 . 
         [0052]    In the case that the subsystem to which the second heat exchanger assembly  28  is connected has a reduced need for airflow through the assembly  28 , e.g. due to a reduction in the cooling requirements for the subsystem, the bypass baffle  34   b  may be controlled to hinge to the open position, as shown in  FIG. 5 . In this situation, a portion of the airflow through the first heat exchanger assembly  26  is allowed to bypass the second heat exchanger assembly  28  completely, thereby reducing the cooling level of the second heat exchanger assembly  28 . 
         [0053]    It will be understood that the angular position of the bypass baffle  34   b  may be controlled to adjust the level of airflow that bypasses the second heat exchanger assembly  28 , thereby controlling the cooling level of the second heat exchanger assembly  28  for a given fan flow level. Furthermore, while the bypass baffle  34   b  is shown as a hinged baffle, it will be understood that other baffle constructions may be used, e.g. a roller shutter baffle, a telescoping baffle member, etc. 
         [0054]    In a further embodiment of the invention, the use of an adjustable baffle can allow for the variation of airflow through heat exchangers which are provided as part of a heat exchanger assembly. In  FIGS. 6 and 7 , the first heat exchanger assembly  26  comprises an upper heat exchanger  26   a  and a lower heat exchanger  26   b . An adjustable baffle  34   c  is provided downstream of the first heat exchanger assembly  26 , and arranged to control the flow path for airflow drawn through the heat exchanger system  24  by the fan  30 . The baffle  34   c  is illustrated as a hinged baffle member, hingedly mounted at the downstream side of the first heat exchanger assembly  26 , and operable to hinge between a lower position, as shown in  FIG. 6 , and an upper position, as shown in  FIG. 7 . 
         [0055]    In  FIG. 6 , the upper heat exchanger  26   a  has a greater cooling requirement than the lower heat exchanger  26   b . Accordingly, the baffle  34   c  is hinged to the lower position, to define a flow path for the heat exchanger system  24  wherein airflow is primarily drawn through the upper heat exchanger  26   a , while the flow path through the lower heat exchanger  26   b  is largely blocked or restricted by the baffle  34   c  in the lower position. 
         [0056]    Similarly, when the lower heat exchanger  26   b  has a greater cooling requirement than the upper heat exchanger  26   b , the baffle  34   c  is hinged to the upper position as shown in  FIG. 7 . As a result, airflow is primarily drawn through the lower heat exchanger  26   b , while the flow path through the upper heat exchanger  26   a  is largely blocked or restricted by the baffle  34   c  in the upper position. 
         [0057]    As a result of the adjustment of the position of the baffle  34   c , the proportion of airflow through the upper and lower heat exchangers  26   a , 26   b  can be varied, resulting in improved performance control for the overall heat exchanger system  24 . It will be understood that the angular position of the baffle  34   c  may be controlled to adjust the proportional level of airflow that flows through the heat exchangers  26   a , 26   b . In addition, it will be understood that the baffle  34   c  may be positioned at a neutral position, e.g. aligned in a horizontal direction, or retracted such that equal airflow is provided through the upper and lower heat exchangers  26   a , 26   b . Furthermore, while the bypass baffle  34   b  is shown as a hinged baffle, it will be understood that other baffle constructions may be used, e.g. a roller shutter baffle, a telescoping baffle member, etc. 
         [0058]    The operation of the adjustable baffles  34   a , 34   b , 34   c  may be controlled from a central computer provided in the tractor, and/or an engine control unit (ECU) arranged to adjust engine performance based on sensor inputs. In a further aspect, the heat exchanger systems may be provided with an auxiliary adjustable baffle (not shown) which may be arranged upstream of the first heat exchanger assembly  26 , to control or redirect airflow drawn into the first heat exchanger assembly  26 . The auxiliary adjustable baffle may comprise any suitable baffle construction, such as those described in the above embodiments. 
         [0059]    Examples of use cases for the adjustable baffle system can include:
       When defrosting windows, e.g. upon starting a vehicle in the morning, high air flow is required on the HVAC condenser to improve HVAC performance. Accordingly, other coolers may be bypassed, and/or additional airflow may be redirected to such a condenser.   When a heat exchanger assembly is part of an occasionally high consumption subsystem, and requires additional cooling based on the operational tasks being performed, e.g. tractor hydraulics. Accordingly, other coolers may be bypassed, and/or additional airflow may be redirected to the associated hydraulic oil cooler.       
 
         [0062]    It will be understood that the features of the different embodiments may be combined with each other, to provide for increased levels of system operation and control. The use of an adjustable baffle  34   a , 34   b , 34   c  allows for greater control over the heat exchanger airflow, and how the airflow is allocated to different heat exchangers in the system. 
         [0063]    The invention is not limited to the embodiments described herein, and may be modified or adapted without departing from the scope of the present invention.