Patent Publication Number: US-2019168577-A1

Title: An Improved Cooling System For A Vehicle Cab

Description:
FIELD OF THE INVENTION 
     The present invention relates to cooling systems for vehicle cabs, and in particular cooling systems for vehicle cabs which use the waste heat from exhaust gases of the vehicle. 
     BACKGROUND OF THE INVENTION 
     It is known for vehicle cooling and air conditioning systems to use the waste heat of the engine exhaust as part of an absorption system in order to provide cold air to the interior of the vehicle. WO90/00479 discloses an air conditioning system which provides continuous cooling to the cabin of a vehicle by way of a pair of sorption vessels through which exhaust gases are selectively passed. 
     Specifically, WO&#39;479 discloses two sorption vessels in sealed circuits and a diverter valve which can selectively divert exhaust gas through one of the sorption vessel arrangements while the other vessel is receiving a flow of ambient cooling air. 
     The diverter valve used to selectively divert ambient air or exhaust gas over each sorption vessel arrangement is a three-way valve and the system requires additional pipework to connect the exhaust to the system. A three-way valve employed for this purpose is costly to manufacture and susceptible to wear after long periods of use, whilst the additional pipework also adds to the cost of the system. 
     It is an aim of the present invention to obviate or mitigate these disadvantages in such prior art systems. 
     SUMMARY OF THE INVENTION 
     According to a first aspect of the present invention there is provided a cooling system for a vehicle cab where the vehicle has an internal combustion engine, the system comprising:
         a cooling chamber having an ambient air intake;   first and second pairs of sorption vessels, each pair of sorption vessels comprising a first sorption vessel containing a sorption solution which is located in the cooling chamber and is in fluid communication with a second sorption vessel located outside the cooling chamber;   first and second cooling circuits, each circuit containing a coolant and being in heat exchange contact with a respective one of the second sorption vessels;   a first control valve which selectively directs coolant from the first or the second cooling circuit towards the cab;   an exhaust passage conveying exhaust gases away from the engine, the exhaust passage having at least one exhaust aperture in communication with the cooling chamber;   and   a moveable flap located within the cooling chamber so as to divide the cooling chamber into a first chamber portion containing one of the first sorption vessels, and a second chamber portion containing the other of the first sorption vessels,   wherein the moveable flap is moveable between: (i) a first position in which exhaust gas flows from the at least one exhaust aperture through the first chamber portion whilst ambient air flows from the air intake through the second chamber portion, and (ii) a second position in which exhaust gas flows from the at least one exhaust aperture through the second chamber portion whilst ambient air flows from the air intake through the first chamber portion.       

     According to a second aspect of the present invention there is provided a vehicle comprising:
         an internal combustion engine;   a cab; and   a cooling system according to the first aspect of the invention.       

     According to a third aspect of the present invention there is provided a method of continuously cooling a vehicle cab where the vehicle comprises:
         an internal combustion engine;   a cooling chamber having an ambient air intake; and   a cooling system according to the first aspect of the invention;   the method comprising the steps of:   (i) moving the moveable flap to the first position;   (ii) simultaneously actuating the first control valve such that coolant is directed from the first cooling circuit towards the cab;   (iii) after a predetermined period of time or in response to a control signal moving the moveable flap from the first position to the second position;   (iv) simultaneously actuating the first control valve such that coolant is directed from the second cooling circuit towards the cab; and   (v) after a predetermined period of time or in response to a control signal repeating steps (i)-(iv).       

    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Preferred embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which: 
         FIG. 1  shows a front perspective view of a cooling system for a vehicle cab according to an embodiment of the present invention; 
         FIG. 2  shows a rear perspective view of the cooling system for a vehicle cab of  FIG. 1 ; 
         FIG. 3  shows a plan view of the cooling system for a vehicle cab of  FIG. 1 ; 
         FIG. 4  shows a side view of the cooling system for a vehicle cab of  FIG. 1 ; 
         FIG. 5  shows a horizontal section view of the cooling system for a vehicle cab of  FIG. 1  in a first state; 
         FIG. 6  shows a horizontal section view of the cooling system for a vehicle cab of  FIG. 1  in a second state; 
         FIG. 7  shows a detail view of the cooling system for a vehicle cab of  FIG. 1 ; 
         FIG. 8  shows a horizontal section view of the cooling system for a vehicle cab of  FIG. 1  in a third state; and 
         FIG. 9  shows a schematic view of the cooling system of  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION OF THE DRAWINGS 
     With reference to  FIGS. 1 to 9 , there is shown a cooling system  10  for continuously cooling a vehicle cab  13  which has an internal combustion engine  11 , hereinafter referred to as the cooling system  10 . The cooling system  10  includes first and second pairs of sorption vessels  12 ,  14 . Each pair of sorption vessels  12 ,  14  comprises a first sorption vessel  12   a ,  14   a  and a second sorption vessel  12   b ,  14   b . The first sorption vessels  12   a ,  14   a  are located inside of a cooling chamber  17 , and the second sorption vessels  12   b ,  14   b  are located outside of the cooling chamber  17 . 
     In  FIGS. 5 and 6 , there is shown a sectional view of the first sorption vessels  12   a ,  14   a . The first sorption vessels  12   a ,  14   a  comprise a plurality of spaced apart aligned plates  20 . The space between plates  20  is occupied by foam  21 , for example an alumina-zeolite foam, capable of absorbing a sorption solution. A plurality of exhaust vessel passages  24  suitable for the passage of air extend orthogonally to and through the plates  20 , across each first sorption vessel  12   a ,  14   a.    
     The sorption solution is a wet salt solution comprising a hygroscopic salt. The second sorption vessels  12   b ,  14   b  are capable of receiving fluid evaporated from the first sorption vessels  12   a ,  14   a . The first  12   a ,  14   a  and second  12   b ,  14   b  sorption vessels are in fluid communication with one another via a sorption fluid passage  23  which connects the two vessels. Each pair of sorption vessels  12 ,  14  is a closed loop. 
     The second sorption vessels  12   b ,  14   b  can act as condenser/evaporators. The second sorption vessels  12   b ,  14   b  are in heat exchange contact with first and second cooling circuits  30 ,  32 , respectively. For the avoidance of any doubt, it should be understood that heat exchange contact means any arrangement in which heat can be transferred from the cooling circuits  30 ,  32  to their associated second sorption vessel  12   b ,  14   b  and vice-versa. In a preferred embodiment, each cooling circuit  30 ,  32  includes a coil portion which coils around the exterior of its respective second sorption vessel  12   b ,  14   b.    
     The first and second cooling circuits  30 ,  32  are filled with a coolant such as an ammonia solution or liquid carbon dioxide. The cooling circuits  30 ,  32  are also in heat exchange contact with the cab  13 , as will be described in more detail below, so that they can transport heat to the cab  13  or receive heat from the cab and transport heat away from the cab. 
     As best depicted in  FIG. 9 , the first and second cooling circuits  30 ,  32  pass through a first control valve  18 . The first control valve  18  may be a standard three-way valve of a known type. The first control valve  18  is located inside a manifold  22 , depicted in  FIG. 9 . The first control valve  18  selects whether coolant from the first or the second cooling circuit  30 ,  32  is directed to the cab  13  via the manifold outlet  25 . The coolant is fed from the manifold outlet  25  to an air conditioning unit  19  located inside the cab  13 . The coolant then returns to the manifold inlet  27  and back to the first control valve  18 . 
     The flow of fluid through the sorption fluid passage  23  is controlled by a second control valve  26 , which can move from an open position to a closed position and vice-versa. In the open position, fluid can move between the first  12   a ,  14   a  and second  12   b ,  14   b  sorption vessels and in the closed position fluid is prevented from moving between the first  12   a ,  14   a  and second  12   b ,  14   b  sorption vessels. 
     As shown in  FIGS. 5 and 6 , the cooling chamber  17  is in fluid communication with an air intake  31  which allows ambient air to flow into the cooling chamber  17 . An exhaust passage  33  which carries exhaust gases away from the internal combustion engine  11  of the vehicle extends through the cooling chamber  17 . The cooling chamber  17  is divided into first and second chamber portions  34 ,  36  by a movable flap  38 . The movable flap  38  includes a pivotable portion  40 , and a body portion  42  which extends across the cooling chamber  17  and separates the first and second chamber portions  34 ,  36  from each other. The pivotable portion  40  depicted in  FIGS. 5, 6 and 8  is a hollow cylindrical portion that extends around the circumference of the exhaust passage  33 . The hollow cylindrical portion  40  is rotatable with respect to the exhaust passage  33  such that the body portion  42  is allowed to pivot. The pivot portion  40  includes first and second flap apertures  44 ,  46 . The first flap aperture  44  is located on a first chamber side of the body portion  42 , and the second flap aperture  46  is located on a second chamber side of the body portion  42 . 
     The exhaust passage  33  includes first and second exhaust apertures  48 ,  50 . The first and second flap apertures  44 ,  46  are formed such that can be selectively aligned with the associated exhaust apertures  48 ,  50 . When one of the flap apertures  44 ,  46  is not aligned with its associated exhaust aperture  48 ,  50 , the associated chamber portion is closed to exhaust gas flow from the exhaust passage  33 . When one of the flap apertures  44 ,  46  is aligned with its associated flap aperture, the associated chamber portion is in fluid communication with the exhaust gas from the exhaust gas from the exhaust passage  33 . 
     The movable flap  38  is movable between first and second positions by pivoting using the pivot portion  40 . In the first position, as depicted in  FIG. 5 , the first flap aperture  44  is aligned with the first exhaust aperture  48 . Also in the first position, the movable flap  38  closes the first chamber portion  34  from the air intake, and the second flap aperture  46  is not aligned with the second exhaust aperture  50 . 
     In the second position, as depicted in  FIG. 6 , the second flap aperture  46  is aligned with the second exhaust aperture  50 . Also in the second position, the movable flap  38  closes the second chamber portion  36  from the air intake  31 , and the first flap aperture  44  is not aligned with the first exhaust aperture  48 . 
     As depicted in  FIG. 8 , the movable flap  38  is also movable into a third position by pivoting using the pivot portion  40 . In the third position, the movable flap  38  is positioned such that the first and second flap apertures  44 ,  46  are not aligned with their respective exhaust apertures  48 ,  50 , so the first and second chamber portions  34 ,  36  are closed to gas from the exhaust passage  33  and only receive ambient air from the air intake  31 . 
     Referring to  FIGS. 1 and 2 , air outlets  52  are located downstream of the first sorption vessels  12   a ,  14   b  in the first and second chamber portions  34 ,  36 . Outlet valves  54  are employed to control the flow out of the air outlets  52 . The outlet valves  54  allow any gases in one of the chamber portions  34 ,  36  to flow through the air outlet  52  when the outlet valve  54  is in an open position. The outlet valves  54  are operable to move to a closed position in which they prevent any gases from passing through the air outlets  52 . The actuation of the outlet valves  54  is controlled by the controller  62 . When exhaust gas flows into one of the chamber portions  34 ,  36 , the outlet valve  54  of that chamber portion is closed by the controller  62 . When ambient air from the air intake  30  flows into one of the chamber portions  34 ,  36  the outlet valve  54  of that chamber portion is opened by the controller  62 . 
     The outlet valves  54  are petal valves which include petals  56  that rotate to close and open petal apertures  58 . When the outlet valves  54  are closed the exhaust gas flows out of the chamber portion through an outlet passage  60 . The outlet passage  60  allows any exhaust gas in the first chamber portion  34  to be in fluid communication with the exhaust passage  33  downstream of the exhaust apertures  48 ,  50 . The outlet passage  60  is in fluid communication with the exhaust passage  33  downstream of the first and second exhaust apertures  48 ,  50 . 
     As depicted in  FIG. 9 , the cooling system  10  may further include: a controller  62  and at least one temperature sensor  64 . The controller  62  is adapted to control the movement of the movable flap  38  and the actuation of the first control valve  18 , and is in communication with the temperature sensors  64  in a known way. 
     As depicted in  FIG. 9 , there may be two temperature sensors  64  located in each of the first and second cooling circuits  30 ,  32 . Alternatively, there may be a single temperature sensor  64  located in the vehicle cab  13  instead of, or in addition to the temperature sensors  64  located in each of the first and second cooling circuits  30 ,  32 . 
     The controller  62  moves the moveable flap  38  and actuates the first control valve  18  in response to a signal received from the at least one temperature sensor  64 . For example, if there are temperature sensors  64  located in each cooling circuit  30 ,  32  and/or a temperature sensor located in the cab  13 , the controller  62  may move the flap  38  and control valve  18  if it receives a signal from the at least one temperature sensor  64  that the temperature of the cab  13  or one of the cooling circuits  30 ,  32  is above a pre-determined value. 
     The cooling system  10  may include a timer  66  in addition to, or instead of the at least one temperature sensor  64 . The timer  66  is in communication with the controller  62  in a known way. The controller  62  may move the movable flap  38  and actuate the first control valve  18  when the timer  66  indicates that a predetermined period of time has elapsed. 
     The controller  62  may also be able to control the actuation of the second control valve  26  from the open position to the closed position, and vice-versa. The cooling system  10  may further comprise at least one exhaust temperature sensor  68  located in the exhaust passage  33  just upstream of the exhaust apertures  48 . The exhaust temperature sensor  68  measures the temperature of the exhaust gas flowing into the chamber portions when the moveable flap  38  is in the first or second position respectively. The exhaust temperature sensor  68  is in communication with the controller  62  in a known way. When the controller  62  receives a signal from the exhaust temperature sensor  68  that the temperature of the exhaust gas has reached a pre-determined value, the controller  62  opens the second control valve  26 . This allows vapour to flow from one of the first sorption vessels  12   a ,  14   a  to its respective second sorption vessel  12   b ,  14   b  when the second control valve  26  is opened by the controller  62 . 
     INDUSTRIAL APPLICABILITY 
     With reference to  FIGS. 1 to 9 , a method of continuously cooling a vehicle cab using the previously described cooling system will now be described. 
     Firstly, the movable flap  38  is moved by the controller  62  into the first position, as depicted in  FIG. 5 , such that the first flap aperture  44  is aligned with the first exhaust aperture  48 . This allows exhaust gas to flow into the first chamber portion  34 , and through the exhaust vessel passages  24  of the first sorption vessel  12   a . The outlet valves  54  in the first chamber portion  34  are controlled by the controller such that the outlet valves  54  in the first chamber portion prevent exhaust gas downstream of the exhaust vessel passages  24  in the first chamber portion from flowing out of the air outlets  52 , and only allow exhaust gas to exit through the outlet passage  60 . The exhaust gas flowing through the exhaust vessel  24  causes the liquid of the sorption solution to evaporate leaving behind the salt of the sorption solution. When the controller  62  receives a signal from the exhaust temperature sensor  68  that the temperature of the exhaust gas has reached a pre-determined temperature, the controller opens the second control valve  26  allowing the vapour to flow into the second sorption vessel  12   b . The vapour then condenses inside the second sorption vessel  12   b.    
     The evaporation can continue until all of the sorption liquid has evaporated from the first sorption  12   a  vessel. While condensed sorption liquid is held in the second sorption vessel  12   b , the second sorption vessel  12   b  is in heat exchange contact with, and provides a cooling effect to, the coolant in the first cooling circuit  30 . At the same time as the movable flap  38  is moved into the first position, the controller  62  actuates the first control valve  18  to direct coolant from the first cooling circuit  30  to the cab  13 . 
     Also in the first position, the second flap aperture  46  is not aligned with the second exhaust aperture  50 , and only ambient air from outside the chamber flows from the air intake  31  through the second chamber portion  36 . The outlet valves  54  in the second chamber portion  36  are controlled by the controller  62  such that they are open and allow ambient air to flow through air outlets  52 . The outlet valves  54  in the first chamber portion  34  are controlled by the controller  62  such that they are closed. 
     After a pre-determined period of time indicated by the timer or in response to a signal from the at least one temperature sensor  64  that the cab  13  or one of the cooling circuits  30 ,  32  has reached a pre-determined temperature, the controller  62  moves the moveable flap  38  into the second position such that the second flap aperture  46  aligns with the second exhaust aperture  50  and exhaust gas is allowed to flow into the second chamber portion  36  and now prevented from entering the first chamber portion  34 . The exhaust gas flows through the exhaust vessel passages  24  of the first sorption vessel  14   a . The outlet valves  54  in the second chamber portion are controlled by the controller such that they prevent exhaust gas downstream of the exhaust vessel passages  24  in the second chamber portion from exiting out of the air outlets  52 , and only allow exhaust gas to exit through the outlet passage  60 . The exhaust gas flowing through the exhaust vessel passages  24  causes the liquid of the sorption solution to evaporate leaving behind the salt of the sorption solution. When the controller  62  receives a signal from the exhaust temperature sensor  64  that the temperature of the exhaust gas has reached a pre-determined temperature, the controller  62  opens the second control valve  26  of the second pair of sorption vessels  14  allowing the vapour to flow into the second sorption vessel  14   b . The vapour then condenses inside the second sorption vessel  14   b.    
     The evaporation can continue until all of the sorption liquid has evaporated from the first sorption vessel  14   a . While condensed sorption liquid is held in the second sorption vessel  14   b , the second sorption vessel  14   b  is in heat exchange contact with, and provides a cooling effect to, the coolant in the second cooling circuit  32 . At the same time as the movable flap  38  is moved into the second position, the controller  62  actuates the first control valve  18  to direct coolant from the second cooling circuit  32  to the cab  13 . 
     Also in the second position, the first flap aperture  44  is not aligned with the first exhaust aperture  48 , and only ambient air from outside the chamber flows from the air intake  31  through the first chamber portion  34 . The outlet valves  54  in the first chamber portion  34  are controlled by the controller  62  such that they are open and allow the ambient air to flow through the exhaust vessel passages  24  in the first chamber portion  34  and through the air outlets  52 . The outlet valves  54  in the second chamber portion  36  are controlled by the controller  62  such that they are closed. 
     After a pre-determined period of time indicated by the timer  66  or in response to a signal from the temperature sensor  64  that the cab  13  or one of the cooling circuits  30 ,  32  has reached a certain temperature, the controller  62  moves the moveable flap  38  into the first position to repeat the method of continuously cooling a vehicle cab. 
     If the cooling system  10  is not required, for example, if the air conditioning unit  19  is switched off, the moveable flap  38  can be moved into the third position, as depicted in  FIG. 8 , where only ambient air flows into the cooling chamber  34 . 
     Because the continuous cooling system according to the present invention employs a cooling chamber and a movable flap to selectively divert ambient air or exhaust gas to the first sorption vessels, the cooling system detailed herein is less complicated and consequently less costly to manufacture. 
     In addition, the movable flap is less susceptible to wear and changes in tolerances than three-way valves arrangements. 
     The cooling system disclosed herein can be used in any vehicle comprising: an internal combustion engine and a cab. For example, the vehicle may be a car, truck, tractor or aeroplane. 
     Modifications and improvements may be incorporated without departing from the scope of the invention, which is defined by the appended claims. 
     It should be understood that a plurality of first and second flap apertures and a plurality of first and second exhaust apertures may be used to achieve the effect of the invention described herein. 
     It should be understood that the exhaust temperature sensor may be located in one of the exhaust vessel passages.