PATENT ABSTRACT
A pressure reducing gas storage device, an air-jet system and a motor vehicle are disclosed herein, wherein the pressure reducing gas storage device comprises a gas storage tank including an inlet for receiving compressed air and an outlet for outputting air and a heat exchanger for heating the air in the air input into the gas storage tank. By providing a heat exchanger to heat the air input in the gas storage tank, the phenomenon of being frozen is eliminated and the pressure reducing gas storage device is able to work continuously and stably.

PATENT DESCRIPTION
RELATED APPLICATIONS 
       [0001]    This application is a continuation of PCT Patent Application Serial No. PCT/CN2010/072399, filed May 3, 2010, which claims priority to Chinese Patent Application Serial No. 200910107196.3, filed May 1, 2009 and Chinese Patent Application Serial No. 200910107195.9, filed May 1, 2009, the disclosures of which are incorporated herein by reference. 
     
    
     TECHNICAL FIELD 
       [0002]    The present application relates to a pressure reducing gas storage device, an air-jet system and a motor vehicle. 
       BACKGROUND 
       [0003]    In order to avoid severe environmental pollution and directly utilize the wind resistance airflow encountered by a motor vehicle during while running, U.S. Pat. No. 7,641,005 B2 issued to the applicant of the present application provides an engine comprising left and right wind-powered pneumatic engines arranged symmetrically. Each of the left and right wind-powered pneumatic engines comprises an impeller chamber as well as impeller and vanes arranged therein. Compressed air is used in the engine as main power, and external wind resistance are received for use as auxiliary power, thereby driving the impellers and vanes to operate to generate power output. The power drives the motor vehicle after it is shifted via a central main power output gearbox. 
         [0004]    The above invention firstly proposed a wind-powered pneumatic engine which utilizes high pressure air as the main power and directly utilizes the wind resistance airflow as the auxiliary power, and a motor vehicle in which the need of converting wind resistance airflows into electrical power and the need of a complex mechanic-electric energy conversion system are eliminated, and the structure thereof is simplified. Therefore, a new way to save energy and find a substitute for fuel is provided. 
         [0005]    In order to further optimize the performance of the wind-powered pneumatic engine and improve the operating efficiency of the wind-powered pneumatic engine and the motor vehicle, based on the aforementioned application, another U.S. patent application Ser. No. 12/377,513 (WO 2008/022556) filed by the applicant provides a combined wind-powered pneumatic engine. This engine comprises left and right wind resistance engines operating independently and a plurality of first compressed air engines arranged around the left and right wind resistance engines. The left and right wind resistance engines comprise a second impeller and the first compressed air engines comprise a first impeller. The power outputted by the left wind resistance engines and its peripheral first compressed air engines, as well as the power outputted by the right wind resistance engine and its peripheral first compressed air engines, is outputted as main power through a left power output shaft, a right power output shaft, a reversing wheel and gear. 
         [0006]    However, the above mentioned wind-powered pneumatic engine and motor vehicle using compressed air as the source of main power are still a new technology. Therefore, there remains a need of further perfection and improvement to the structure of the wind-powered pneumatic engine and the motor vehicle employing the wind-powered pneumatic engine as discussed above. So is particularly in view of power performance. 
       SUMMARY OF THE INVENTION 
       [0007]    The object of the present application is to provide a pressure reducing gas storage device, an air jet system and a motor vehicle which are capable of continuously stable working. 
         [0008]    In accordance with an aspect of the present application, a pressure reducing gas storage device comprises a gas storage tank and a heat exchanger. The gas storage tank comprises an inlet for receiving compressed air and an outlet for outputting air. The heat exchanger is used to heat the air in the air input into the gas storage tank. 
         [0009]    The pressure reducing gas storage device further comprises a pressure reducing valve. The compressed air enters the gas storage tank after its pressure is reduced by the pressure reducing valve. The heat exchanger comprises a first heat exchange unit filled with a first medium. The first medium exchanges heat with the air in the gas storage tank so as to heat the air. The pressure reducing gas storage device further comprises a cooler and a first circulating pump. The first heat exchange unit, the cooler and the first circulating pump form an inner circulating cooling system. The first medium circulates within the first heat exchange unit and the cooler. The cooler exchanges heat with ambient air. The first heat exchange unit has a first temperature regulation chamber which surrounds the gas storage tank. The first medium is filled between the first temperature regulation chamber and the gas storage tank. The two ends of the cooler are connected to the temperature regulation chamber. 
         [0010]    The heat exchanger further comprises a second heat exchange unit. The inlet, the first heat exchange unit, the second heat exchange unit and the outlet are arranged in turn. The second heat exchange unit has a second temperature regulation chamber, a second medium and a heater. The second temperature regulation chamber surrounds the gas storage tank. The second medium is filled between the second temperature regulation chamber and the gas storage tank. The heater is provided on the second temperature regulation chamber and heats the second medium. The second medium exchanges heat with the air in the gas storage tank. The second temperature regulation chamber is connected to a radiator and the second medium circulates within the second temperature regulation chamber and the radiator. The radiator exchanges heat with ambient air. 
         [0011]    A motor vehicle refrigeration system comprises a gas storage tank, a pressure reducing valve, a heat exchanger, a cooler and a first circulating pump. The gas storage tank receives compressed air the pressure of which is reduced by a pressure reducing valve. The first heat exchange unit, the cooler and the first circulating pump form an inner circulating cooling system. The first medium circulates within the first heat exchange unit and the cooler. The cooler exchanges heat with ambient air. 
         [0012]    A compressed air engine comprises a housing, an impeller body arranged in the housing and an air-jet system. The output of the air-jet nozzle is used to eject compressed air onto the impeller body within the housing. 
         [0013]    The pressure reducing valve comprises a housing, a valve core located within the housing, an regulation block and an elastic body. The valve core is sealingly and slidably fitted with the housing. The housing has a housing cavity axially running therethrough and an airway radially running therethrough. The housing cavity is connected to an air intake pipeline by which the housing cavity is connected to the gas storage tank. The valve core has a sealing end and a regulation end and the elastic body is arranged between the regulation block and the regulation end of the valve core. The regulation block is fixed with the housing and the valve core has a first position and a second position. In the first position, the sealing end blocks the air intake pipeline to disconnect the air intake pipeline with the gas storage tank; and in the second position, the sealing end is apart from the air intake pipeline to connect the air intake pipeline with the gas storage tank. 
         [0014]    The pressure reducing valve comprises a first control valve and a second valve. The first control valve comprises a first valve seat having a cavity, a first valve plug, a second elastic body, a first gas pipeline, a second gas pipeline, a third pipeline and a fourth pipeline. The first valve plug is arranged in the cavity and divides the cavity into a first chamber and a second chamber. The first valve plug is sealingly and slidably fitted with the first valve seat. The second elastic body is arranged in the second chamber and supports the first valve plug. The second gas pipeline connected to the first gas pipeline is connected to the second chamber. The third gas pipeline connects the first chamber with the second chamber. Both of the fourth gas pipeline and the first gas pipeline are connected with the first chamber. The cross-sectional area of the second gas pipeline is less than that of the third gas pipeline. The second control valve connected to the third gas pipeline controls the gas flow in the third gas pipeline. The first valve plug has a first position and a second position along the sliding direction. At the first position the first valve plug blocks the first gas pipeline to disconnect the first gas pipeline and the first chamber, and at the second position the first valve plug departs from the first gas pipeline to connect the first gas pipeline with the first chamber. 
         [0015]    An air-jet system comprises a compressed air tank for storing compressed air, a distributor for transporting compressed air to the compressed air engine, and a pressure reducing gas storage device. The output of the compressed air tank is connected to an inlet of the pressure reducing gas storage device via a pipeline and the outlet of the pressure reducing gas storage device is connected to the distributor. 
         [0016]    A motor vehicle comprises wheels, a drive train, a compressed air engine and an air-jet system. The air jet system, the compressed air engine, the drive train and the wheels are power connected in turn. 
         [0017]    The present application has the following technical effects. When the applicant of this application tested a motor vehicle using a compressed air engine, he found that the power of the motor vehicle is usually insufficient after running a long time. In this case, the applicant had to stop testing and check each part of the motor vehicle, but he failed to find the malfunction until he once found that the air-jet nozzle was condensed and frozen so that it cannot normally eject gas. Based on an analysis of the above situation, the applicant further found that the pressure reducing valve is also easy to be frozen. As for this case, the phenomenon of being frozen is eliminated by providing a heat exchanger to heat the air input in the gas storage tank. In addition, by providing a cooler, the temperature of ambient air is reduced and energy is saved. By providing a heater, not only the working stability of compressed air is further improved, but also the heating of the motor vehicle is achieved. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0018]      FIG. 1  is a schematic structural view showing the connection of a compressed air tank, an air-jet system and a compressed air engine of a motor vehicle. 
           [0019]      FIG. 2  is a schematic structural view showing the air pressure regulator of the motor vehicle at a close configuration. 
           [0020]      FIG. 3  is a schematic structural view showing the air pressure regulator of the motor vehicle at an open configuration. 
           [0021]      FIG. 4  is a sectional view along the line A-A in  FIG. 3 . 
           [0022]      FIG. 5  is a schematic structural view of the motor vehicle (only two wheels are illustrated). 
           [0023]      FIG. 6  is a top schematic view of the motor vehicle. 
           [0024]      FIG. 7  is a top schematic view showing a wind resistance engine and a compressed air engine assembled together. 
           [0025]      FIG. 8  is a front schematic view showing the wind resistance engine and the compressed air engine assembled together. 
           [0026]      FIG. 9  is a front schematic view of a compressed air engine of the motor vehicle. 
           [0027]      FIG. 10  is a top schematic view of the compressed air engine of the motor vehicle. 
           [0028]      FIG. 11  and  FIG. 12  are schematic diagrams respectively illustrating a wind resistance engine and a compressed air engine connected in parallel and in series. 
           [0029]      FIG. 13  is a schematic structural view of a nozzle. 
           [0030]      FIG. 14  is a top view of a motor vehicle according to a second embodiment. 
           [0031]      FIG. 15  is a top view of a motor vehicle according to a third embodiment. 
           [0032]      FIG. 16  is a top view of a motor vehicle according to a fourth embodiment. 
           [0033]      FIG. 17  is a schematic structural view showing a flow regulating valve being closed according to the fifth embodiment. 
           [0034]      FIG. 18  is a schematic structural view showing a flow reducing valve being opened according to the fifth embodiment. 
           [0035]      FIG. 19  is a schematic structural view illustrating a connection relationship among a flow reducing valve, a compressed air tank, a distributor and a transmission mechanism according to the fifth embodiment. 
           [0036]      FIG. 20  is a top view of a motor vehicle utilizing another kind of wind resistance engine. 
           [0037]      FIGS. 21-23  are front sectional view, side sectional view and top view of the wind resistance engine in  FIG. 20 . 
       
    
    
     DETAILED DESCRIPTION 
       [0038]    As shown in  FIG. 1  to  FIG. 8 , a motor vehicle according to this embodiment comprises an air-jet system, a compressed air engine  4 , wind resistance engines  3 ,  3 ′, a drive train  11  and wheels  123 . The air-jet system has an air-jet nozzle  60  and the compressed air engine  4  has a primary power output shaft  120 . The air-jet nozzle  60  of the air-jet system ejects gas to the compressed air engine  4 . The compressed air engine  4  compresses gas and then expands gas so that the primary power output shaft  120  of the compressed air engine  4  is driven to rotate, which drives the wheels  123  to rotate via the drive train  11 . The drive train  11  may comprise a gearbox  112 , a universal transmission device  113  connected to the gearbox  112 , and a drive axle  114  connected to the universal transmission device  113 . A first clutch  56  is provided between the primary power output shaft  120  of the compressed air engine  4  and the drive train  11 . The drive axle  114  is connected to the wheels  123 . 
         [0039]    As shown in  FIG. 1  to  FIG. 4 , the air-jet system comprises a compressed air tank  20  for storing compressed air, a pressure reducing gas storage device, a distributor  30  and the air-jet nozzle  60 . The output of the compressed air tank  20  is connected to an inlet of the pressure reducing gas storage device via a pipeline  3 . The outlet of the pressure reducing gas storage device is connected to the air-jet nozzle  60  via the distributor  30 . The distributor  30  is used to distribute the gas outputted by the pressure reducing gas storage device into multiple routes of gas, each of which is ejected by a corresponding air-jet nozzle  60 . The pressure reducing gas storage device comprises a gas storage tank and a heat exchanger. The gas storage tank comprises a first air chamber  2  having a first inlet  21  and a first outlet  22 . The first inlet  21  is used to input air and the first outlet  22  is used to output air. The two ends of the pipeline  3  are connected to the compressed air tank  20  and the first inlet  21  of the first air chamber  2 , respectively. There may be provided one or more pipelines  3 . The cross section area of the pipeline  3  is less than that of the compressed air tank  20  and less than that of the first air chamber  2 . The heat exchanger comprises a first heat exchange unit  40  arranged on the first air chamber  2 . The first heat exchange unit  40  comprises a first temperature regulation chamber  41  surrounding the first air chamber  2  and a first medium  42  filled between the first temperature regulation chamber  41  and the first air chamber  2 . The first medium  42  may be liquid (for example, water) or gas or other heat exchangeable mediums. The temperature of the first medium  42  is higher than that of the gas within the first air chamber  2  so that the compressed air in the compressed air tank  20  is released into the first air chamber  2  via the pipeline  3  and then exchanges heat with the first medium  42 . The heated air is output from the first outlet  22  of the first air chamber  2 . The first air chamber  2  may be made of a material having good heat conduction property so as to facilitate the heat exchange of the air in the first air chamber  2  with the first medium  42 . The first temperature regulation chamber  41  may be made of a material which is thermal insulation or has poor heat conduction property so that the heat is difficult to be dissipated into the ambient air. 
         [0040]    The first heat exchange unit  40  is connected to a cooler  5 . Each of the two ends of the cooler  5  is connected to the first temperature regulation chamber  41  to form a refrigeration cycle loop. The cooler  5  is provided with a first circulating pump  51  and a first circulating pump switch  52  for controlling the switch of the first circulating pump  51 . The temperature of the first medium  42  in the first temperature regulation chamber  41  decreases after the first medium  42  exchanges heat with the air in the first air chamber  2 . The first medium  42  of which the temperature is decreased circulates in the cooler  5  and the first temperature regulation chamber  41 . A refrigeration air-conditioning circulates the ambient air to exchange heat with the cooler  5  so that the ambient air is cooled to achieve refrigeration effect. 
         [0041]    The air output from the compressed air tank  20  is ejected via the air-jet nozzle  60  after it is heated by the first heat exchange unit  40  of the pressure reducing gas storage device so that condensation or even freeze will not be occurred at the air-jet nozzle  60  due to lower temperature. Meanwhile, the effect of decreasing the temperature of ambient air is achieved by connecting the first heat exchange unit  40  to the refrigeration air-conditioning and using the first medium  42  whose temperature has been decreased as circulating medium. Therefore, energy is saved. 
         [0042]    As shown in  FIG. 2  to  FIG. 4 , the air-jet system may further comprise an air pressure regulator  6  for maintaining the air pressure in the first air chamber  2  at a predetermined value. The air pressure regulator  6  comprises a housing  610 , a valve core  620 , an elastic body  630 , a locking block  640  and a regulating block  650 . The housing  610  is mounted at the first inlet  21  of the first air chamber  2  via a fastener  14 . The housing  610  is partly located within the first air chamber  2  and partly extends out of the first air chamber  2 . The housing  610  has a housing cavity  611  axially running therethrough and an airway  612  radially running therethrough. The housing cavity  611  is in communication with an air intake pipe  613  which is in communication with the pipeline  3 . The airway  612  is in communication with the first air chamber  2 . The valve core  620  is located within the housing cavity  611  and sealingly and slidably fitted with the housing. Two ends of the valve core  620  in the axial direction of the housing  610  are a sealing end  621  and a regulation end  622 . The sealing end  621  may seal the airway  612  and the air intake pipe  613 . The elastic body  630  may be capable of deforming expansively along the axial direction of the housing  610 . Two ends of the elastic body  630  bear against the regulation end  622  of the valve core  620  and the regulating block  650 , respectively. The regulating block  650  is thread connected to the housing  610 , and the locking block  640  is thread connected to the housing  610  and presses the regulating block  650  against the elastic body  630 . The regulating block  650  and the locking block  640  have axially running through first and second lead holes  651 ,  641 , respectively. The first and second lead holes  651 ,  641  communicate with each other to guide gas into the housing cavity  611  and onto the regulation end  622  of the valve core  620 . The diameter of the first lead hole  651  is less than that of the second lead hole  641 . The sealing end  621  of the valve core is in the form of truncated cone, and an elastic sealing ring  623  is fixed on the contour surface of the sealing end  621 . An elastic sealing ring  623  is also fixed on the contour surface of the regulation end of the valve core. On the section perpendicular to the axis of the housing  610 , the cross section area of the sealing end  621  of the valve core is less than that of the regulation end  622 . The pressure applied on the sealing end  621  includes the air pressure of the air input from the pipeline  3 , and the pressure applied on the regulation end  622  includes the air pressure of the air in the first air chamber  2  and the elastic force of the elastic body  630 . The elastic body is for example a spring, or other components capable of deforming expansively along the axis direction of the housing  610 . 
         [0043]    The working principle of the air pressure regulator is described below. When the air pressure of the gas input via the pipeline  3  is stable, a pressure reducing passage  614  is formed between the valve core  620  and the housing  610  so that the gas in the pipeline  3  can enter the first air chamber  2  through the pressure reducing passage  614  and the airway  612 . When the air pressure of the gas input via the pipeline  3  is higher than a predetermined value, the air pressure of the input gas pushes the valve core  620  to move toward the side of the regulation end  622 , and thereby the volume of the pressure reducing passage  614  increases and the air pressure in the first air chamber  2  decreases. When the air pressure of the gas input via the pipeline  3  is lower than the predetermined value, the force applied to the regulation end  622  is larger than that applied to the sealing end  621  so that the valve core moves toward the side of the sealing end  621 , and thereby the volume of the pressure reducing passage  614  decreases and the air pressure in the first air chamber  2  increases. When the air pressure of the gas input via the pipeline  3  changes, the valve core moves linearly according to the variation of the forces applied to the sealing end  621  and the regulation end  622  so as to stabilize the air pressure in the first air chamber  2  at a predetermined air pressure. When the air pressure regulator is turned off, the sealing end  621  blocks the airway  612  and the air intake pipe  613  and the gas in the pipeline  3  cannot enter the first air chamber  2 . The air pressure of the gas outputted by the pressure reducing gas storage device can be stabilized at a predetermined air pressure by providing the air pressure regulator. 
         [0044]    The prestressing force of the elastic body  630  may be adjusted by screwing or unscrewing the regulation block  640  so that the initially set air pressure of the air pressure regulator may be changed. 
         [0045]    The pressure reducing gas storage device may further comprise a second air chamber  7  and a second heat exchange unit  8 . In the direction of airflow, the first air chamber  2  is in front of the second air chamber  7 . The second air chamber  7  has a second inlet  71  and a second outlet  72 . The second inlet  71  is connected to the first outlet  22  of the first air chamber  2 . The second heat exchange unit  8  comprises a second temperature regulation chamber  81  surrounding the second air chamber  7 , a second medium  82  such as liquid or gas filled between the second temperature regulation chamber  81  and the second air chamber  7 , and a heater  83  for heating the second medium  82 . The heater  83  is for example, a solar energy heater, electrical heater, microwave heater or other heaters capable of heating a medium. There can be provided one or more heaters and there also can be provided one or more kinds of heaters. The second temperature regulation chamber  81  is connected to a radiator  9  of a heating air-conditioning to form a heating cycle loop. The radiator  9  is provided with a second circulating pump  901  and a second circulating pump switch  902  for controlling the switch of the second circulating pump  901 . The heated second medium  82  circulates within the second temperature regulation chamber  81  and the radiator  9 . The heating air-conditioning circulates ambient air to exchange heat with the radiator  9  so that the temperature of ambient air increases to achieve the effect of heating. The air may be further heated by the second heat exchange unit  8  after being heated by the first heat exchange unit  40 , so that it is more difficult to condense or even freeze the air-jet nozzle of the air-jet system. The second inlet  71  of the second air chamber  7  may also be provided with a pressure reducing valve  6 . 
         [0046]    In addition, the first temperature regulation chamber  41  and the second temperature regulation chamber  81  are connected via a pipeline to form a cycle loop. This cycle loop is provided with a third circulating pump  903  and a third circulating pump switch  904  for controlling the switch of the third circulating pump  903 . 
         [0047]    The heat exchanger may only comprise a first heat exchange unit which heats air in an air storage tank by means of heat exchange. There can be provided one or more first heat exchange units. The heat exchanger may also only comprise a second heat exchange unit having a heater. There can be provided one or more second heat exchange units. The heat exchanger may also comprise both of the first and second heat exchange units. When the first heat exchange unit is used, not only air may be heated, but also the cooled first medium may be used as medium to reduce the temperature in the motor vehicle. When the second heat exchange unit is used, the heated second medium may be used as medium to increase the temperature in the motor vehicle. 
         [0048]    As shown in  FIG. 6  to  FIG. 8 , there are provided two wind resistance engines arranged symmetrically, namely, a first wind resistance engine  3  and a second wind resistance engine  3 ′. The first wind resistance engine comprises a first casing  117 , a first impeller chamber  43  enclosed by the first casing  117 , a plurality of first impellers  44  and a first impeller shaft  45 . Each of the first impellers  44  is fixed on the first impeller shaft  45  and located within the first impeller chamber  43 . The first casing  117  is provided with a first air intake  1  for receiving front resistance fluid during the running of the motor vehicle. The first air intake  1  has an external opening and an inner opening. The caliber of the external opening is larger than that of the inner opening. The first air intake  1  communicates with the first impeller chamber  43 . The resistance fluid is directed into the first impeller chamber  43  via the first air intake  1  to drive the first impellers  44  and the first impeller shaft  45  to rotate. Auxiliary power is output via the first impeller shaft  45 . The second wind resistance engine  3 ′ comprises a second casing  117 ′, a second impeller chamber  43 ′, a second impeller  44 ′, a second impeller shaft  45 ′ and a second air intake  1 ′ for receiving resistance fluid. The first impeller chamber  43  and the second impeller chamber  43 ′ are arranged independently and do not communicate with each other. The first impeller shaft  45  is parallel with the second impeller shaft  45 ′ and rotates in an opposite direction to the second impeller shaft  45 ′. A first transfer gear  46  is fixed on the first impeller shaft  45  and a second transfer gear  118  is fixed on the second impeller shaft  45 ′. The motor vehicle further comprises a first reversing device, a second reversing device and an auxiliary power output shaft. The first reversing device comprises a reversing gear  119  and a transmission belt  47  and the second reversing device comprises a first drive conical gear  49  and a second drive conical gear  50 . The first drive conical gear  49  engages with the second drive conical gear  50  and the axis of the first drive conical gear  49  is perpendicular to that of the second drive conical gear  50 . The reversing gear  119  engages with the first transfer gear  46  and the axis of the reversing gear  119  is parallel with that of the first transfer gear  46 . The transmission belt  47  is wound around the first drive conical gear  49 , the second transfer gear  118  and the reversing gear  119  which are arranged triangularly. The first drive conical gear  49  is fixed on an auxiliary power output shaft  130 . The power outputted by the first impeller shaft  45  and the second impeller shaft  45 ′ is switched onto the auxiliary power output shaft  130  via the first reversing device, and the power outputted by the auxiliary power output shaft  130  is switched to the drive train  11  of the motor vehicle via the second reversing device. There may be two, one or more than two wind resistance engines. A plurality of impellers fixed on the impeller shafts are mounted in the impeller chamber of the wind resistance engine and the impellers and impeller shafts are driven to rotate by the resistance fluid. 
         [0049]    After the power outputted by the impeller shafts of the wind resistance engine is reversed via the reversing device, it may directly drive the drive train of the motor vehicle, as shown in  FIG. 11 , and it may also be connected in series with the primary power output shaft of the compressed air engine to drive the drive train of the motor vehicle, as shown in  FIG. 12 . 
         [0050]    As shown in  FIG. 6  to  FIG. 8 , The compressed air engine  4  is arranged to be independent of the first and second wind resistance engines  3 ,  3 ′ and located at the back of the first and second wind resistance engines  3 ,  3 ′. The compressed air engine  4  has the primary power output shaft  120  and the second transfer gear  50  is fixed at the end of the primary power output shaft  120 . With the first and second drive conical gears  49 ,  50  which are vertically engaged with each other, the power, which is outputted by the first and second wind resistance engines  3 ,  3 ′, is reversed vertically and outputted to the primary power output shaft  120  of the compressed air engine. 
         [0051]    The motor vehicle is provided with a first clutch  160  via which the power outputted by the first and second wind resistance engines  3 ,  3 ′ is output to the auxiliary power output shaft  130 , as shown in  FIG. 8 . During the starting stage of the motor vehicle, the wind resistance engine does not output power and the first clutch  160  disengages so that the auxiliary power output shaft  130  would not be rotated with the primary power output shaft  120 , thus reducing the starting load of the motor vehicle. During the normal running of the motor vehicle, the first clutch  160  engages, the power outputted by the auxiliary power output shaft  130  and that outputted by the primary power output shaft  120  together drive the drive train  11  of the motor vehicle. The first clutch  160  may be for example a prior art one-way clutch, overrunning clutch, etc, and of course may also be other clutches having disengaging and engaging states. 
         [0052]    As shown in  FIG. 6  to  FIG. 10 , the compressed air engine  4  further comprises a housing and a round impeller body  74  located within the housing  70 . The housing comprises an annular side casing  72 , an upper cover plate  73  and a lower cover plate  73 ′. The upper cover plate  73  and lower cover plate  73 ′ are respectively fixed at the upper and lower openings of the annular side casing  72  so that the annular side casing  72 , the upper cover plate  73  and lower cover plate  73 ′ form a closed impeller body chamber  68 . The impeller body  74  is located within the impeller body chamber  68  and the central portion of the impeller body  74  is fitted on the primary power output shaft  120 . By notching on the circumference surface of the impeller body  74  which joints with the inner surface of the side casing  72 , a set of working chambers  69  are formed and distributed evenly around the axis of the primary power output shaft  120 . On the section perpendicular to the axis of the primary power output shaft  120 , the working chamber  69  takes a form of a triangle formed by three curves connected end to end. There may be one or more sets of working chambers  69 . The working chambers may be a thorough-slot structure axially running through on the impeller body. The inner surfaces of the upper cover plate, the lower cover plate and the side casing close the working chamber. The working chambers may also be of a non-thorough-slot structure provided in the middle of the circumference surface of the impeller body and the inner surface of the side casing closes the working chambers. Of course, the working chamber may also be closed by the inner surfaces of the upper cover plate and the lower cover plate, or by the inner surfaces of the lower cover plate and the side casing. That is to say, the working chambers are closed by the inner surface of the casing. 
         [0053]    The inner surface of the side casing  72  is also provided with a plurality of ejecting inlets  67  and a plurality of ejecting outlets  64 . The ejecting inlets  67  and ejecting outlets  64  are arranged alternately. An annular first-order silencer chamber  63  is also provided within the side casing  72 . A plurality of first-order exhaust ports  65  are provided on the external surface of the side casing  72 , and each of the ejecting outlets  64  has a corresponding first-order exhaust port  65 . The ejecting outlets  64  communicate with the first-order exhaust ports  65  via the first-order silencer chamber  63 . The ejecting inlets  67  communicates with none of the ejecting outlets  64 , the first-order exhaust port  65  and the first-order silencer chamber  63 . The ejecting outlets  64  and their corresponding first-order exhaust port  65  are spaced at an angle on the circumference centered on the axis of the primary power output shaft  120 . An air-jet nozzle seat  71  is fixed on the position corresponding to each of the ejecting inlets  67  on the side casing  72 . Each air-jet nozzle seat  71  is fixed with two air-jet nozzles  60 . Each of the air-jet nozzles  60  extends into the corresponding ejecting inlet  67  and is connected to a gas ejecting pipe  54 , and the axes of the two air-jet nozzles  60  on each of the ejecting inlets  67  form an acute angle. The compressed air in the compressed air tank  20  is transferred into the working chambers  69  via the gas ejecting pipe  54  and the air-jet nozzle  60 . For each working chamber  69 , the air ejected by the air-jet nozzle  60  drives the impeller body  74  to rotate and is compressed to be temporarily stored in the working chambers  69 . When moving to the ejecting outlets  64 , the temporarily stored gas in the working chamber  69  expands and jets out from the ejecting outlets  64  at a high speed. The reaction force formed when the gas is ejected again drives the impeller body  74  to rotate. When the impeller body  74  rotates, the primary power output shaft  120  is driven to rotate, which further drives the drive train  11  of the motor vehicle. 
         [0054]    For each working chamber  69 , it takes a period of time from receiving the gas ejected by the air-jet nozzle  60  to ejecting the gas from the ejecting outlets  64 . During the period of time, the gas is compressed and temporarily stored in the working chamber  69  so that the reaction force formed when the gas is ejected is larger and thus more power can be provided for the motor vehicle. Since the working chamber  69  is closed by the inner surface of the housing, it facilitates the compression and temporary storage of the compressed gas. In addition, in order to prevent the compressed gas from being condensed when being input to the compressed air engine, the air-jet nozzle seat  71  may be provided with a first heater  77  for heating the air-jet nozzle  60 . The first heater  77  may be an electrically heated wire which is embedded in the air-jet nozzle seat  71 . As shown in  FIG. 13 , the air-jet nozzle  60  comprises an air-jet nozzle body  617  having an axially running through cavity  618 . The air-jet nozzle body  617  is provided with a second heater  615 . The second heater  615  is an electrically heated wire which is wounded around the air-jet nozzle body  617 . The air-jet nozzle body is also provided with a heat insulation layer  616 . The second heater  615  is located between the heat insulation layer  616  and the air-jet nozzle body  617 . The first and second heaters may be selected from a group consisting of an electrical heater, a microwave heater and a solar energy heater. 
         [0055]    The motor vehicle further comprises a first electromotor  53  which is power connected with the primary power output shaft  120  of the compressed air engine  4  via a belt transmission mechanism  51 . The belt transmission mechanism  51  comprises a pulley  511  and a belt  512  wounded around the pulley  511 . 
         [0056]    As shown in  FIG. 6  to  FIG. 8 , the motor vehicle further comprises a compressed air reuse system for communicating the first-order exhaust ports  65  of the compressed air engine with the impeller chambers  43 ,  43 ′ of the wind resistance engines. The compressed air reuse system comprises a first-order exhaust pipe  57 , a second-order silencer chamber  59  and a second-order exhaust pipe  58 . The inlets of the first-order exhaust pipe  57  communicate with the first-order exhaust ports  65 , respectively, and the outlets of the first-order exhaust pipe  57  are gathered to the second-order silencer chamber  59 . The second-order silencer chamber  59  communicates with the inlets of the second-order exhaust pipe  58 . The outlets of the second-order exhaust pipe  58  communicate with both of the first impeller chamber  43  and the second impeller chamber  43 ′. The gas ejected at a high speed from the ejecting outlets  64  of the compressed air engine passes through the first-order silencer chamber  63  and the first-order exhaust port  65  in turn, then enters the first-order exhaust pipe  57  and after being silenced by the second-order silencer chamber  59 , finally enters the first and second impeller chambers  43 ,  43 ′ to drive the first and second impellers to rotate so as to reuse the compressed air. Accordingly, energy can be saved effectively and the driving force of the motor vehicle can be further improved. 
         [0057]      FIG. 14  illustrates a second embodiment of the motor vehicle, which differs from the first embodiment mainly in that the first and second wind resistance engines  3 ,  3 ′ are of horizontal type mounting and the first and second impeller shafts  45 ,  45 ′ are mounted horizontally and perpendicular to the primary power output shaft  120 . In the first embodiment, the first and second wind resistance engines  3 ,  3 ′ are of vertical type mounting and the first and second impeller shafts  45 ,  45 ′ are mounted vertically, as shown in  FIG. 8 . As for the second embodiment, although the power outputted by the first and second impeller shafts of the first and second wind resistance engines is converted to be coaxially output after being firstly reversed, it cannot be directly transferred to the drive train since the rotation direction of the coaxial output is perpendicular to that required by the drive train. It is necessary to use a second reversing device to convert the power outputted by the first and second wind resistance engines to the rotation direction which is identical to the rotation direction of the drive train. 
         [0058]      FIG. 15  illustrates a third embodiment of the motor vehicle, which differs from the first embodiment mainly in that a second clutch  111  is provided between the auxiliary power output shaft  130  commonly used by both of the first and second wind resistance engines  3 ,  3 ′ and the primary power output shaft  120  of the compressed air engine  4 . The power connection or disconnection of the wind resistance engines and the wind resistance engine may be performed by the second clutch  111 . The wind resistance engines according to this embodiment are of horizontal type mounting. 
         [0059]    As shown in  FIG. 16  to  FIG. 19 , a pressure reducing valve  40  is arranged between the distributor  30  and the compressed air tank  20  of the motor vehicle. The pressure reducing valve  40  comprises a first control valve  300  and a second control valve  400 . The first control valve  300  comprises a first valve seat  301 , a first valve plug  302  and an elastic body  303 . The first valve seat  301  has a cavity  304 . The first valve plug  302  is arranged in the cavity  304  and is slidably and sealingly fitted with the first valve seat  301 . The first valve plug  302  is located in the cavity  304  and divides the cavity  304  into a first chamber  305  and a second chamber  306 . The first control valve  300  further comprises a first gas pipeline  307 , a second gas pipeline  308 , a third gas pipeline  309  and a fourth gas pipeline  310 . The first gas pipeline  307  is used to receive the compressed air input from the compressed air tank  20 . The second gas pipeline  308  communicates at one end with the first gas pipeline  307 , and at the other end with the second chamber  306 . The third gas pipeline  309  communicates at one end with the second chamber  306 , and at the other end with the first chamber  305 . The first chamber  305  is connected to the distributor  30  via the fourth gas pipeline  310 . The first gas pipeline  307  has a diameter greater than that of the second gas pipeline  308  and that of the third gas pipeline  309 , and the second gas pipeline  308  has a diameter less than that of the third gas pipeline  309 . The first valve plug  302  has a close position and an open position with respect to the first valve seat  301 . When the first valve plug  302  is at the close position, it blocks the junction between the first gas pipeline  307  and the first chamber  305 , so that the first gas pipeline  307  is disconnected from the first chamber  305 ; and when the first valve plug  302  is at the open position, it is apart from the junction between the first gas pipeline  307  and the first chamber  305  so that the first gas pipeline  307  communicates with the first chamber  305 . 
         [0060]    The first valve plug  302  comprises a columnar main body  311  and a closing portion  312  with a less diameter than that of the main body  311  and having a needle-shaped head. The main body  311  is slidably fitted with the first valve seat  301 . The periphery surface of the main body  311  is surrounded by a first elastic sealing ring  316 , through which the main body  311  is sealingly fitted with the first valve seat  301 . The main body  311  has an axially running through inner chamber  317  in which the closing portion  312  extending into the chamber  305  is disposed and linearly movable with respect to the main body  311 . The elastic body  303  comprises a first elastic body  313  and a second elastic body  314 . The first elastic body  313  is disposed in the inner chamber  317 , with its two ends bearing against the closing portion  312  and a positioning block  315 , respectively. The second elastic body  314  is disposed in the second chamber  306  and is fixed at one end to the bottom  301   a  of the first valve seat  301  and at another end to the positioning block  315 . The positioning block  315  is fixed through thread fitting to the bottom of the inner chamber  317 . A second elastic sealing ring  318  is fixed onto the top surface of the main body  311 . 
         [0061]    The second control valve  400  is disposed on the third gas pipeline  309  for controlling the gas flux in the third gas pipeline  309 . The control on gas flux may comprise controlling changes between flow and non-flow as well as between large flow and small flow. The second control valve  400  comprises a second valve seat  401  and a second valve plug  402 . The second valve plug  402  comprises a second main body  404  and a conical body  405  located at the front end of the second main body  404 . The second valve seat  401  is provided with a gas passage  406  having a gas inlet  407  and a gas outlet  408 , both of which are connected with the third gas pipeline  309 . A control cavity  410  which is cone-shaped corresponding to the cone body is provided within the gas passage  406 . The second main body  404  is thread fitted with the control cavity  410  so that a second gap  403  between the second main body  403  and the control cavity  410  can be adjusted through the thread, thereby a gas flux in the third gas pipeline  309  is controlled. It can be understood for the persons in the art that the second control valve  400  may be implemented by other conventional airflow control means. The second valve plug  402  is connected to the output port of a transmission mechanism  500 , and the input port of the transmission mechanism  500  is coupled with a control switch of a motor vehicle. The transmission mechanism  500  comprises a second transmission mechanism  502  and a power connected first transmission mechanism  501  connecting the control switch with the second transmission mechanism  502 . The second transmission mechanism  502 , such as a belt transmission mechanism, comprises a driving pulley  503  and a driven pulley  504  having a less diameter than that of the driving pulley  503 . A belt  505  is wound around the driving pulley  503  and the driven pulley  504 . The first transmission mechanism  501  moves according to an operation of the control switch to drive the driving pulley  503  to rotate, which further drives the driven pulley  504  to rotate by means of the belt  505 . The driven pulley  504  drives the second valve plug  402  to rotate, rendering the second valve plug  402  screwed or unscrewed with respect to the second valve seat  401 . In other words, the regulation of the flux of the third gas pipeline is carried out by changing size of the second gap  403  between the first valve plug and the first valve seat. When the second gap  403  becomes zero, the second control valve  400  is closed, and the third gas pipeline  309  is disconnected. 
         [0062]    When the compressed air does not enter the pressure reducing valve, the head of the closing portion  312  blocks the junction between the first gas pipeline  307  and the first chamber  305  under the elastic force of the first and second elastic body  313 ,  314 . At this moment, there is a gap between the second sealing ring  318  and the top  301   b  of the first valve seat  301  (or the second sealing ring  318  has reached the top  301   b ). When the compressed air enters the pressure reducing valve, the compressed air aerates into the chamber  306  through the first gas pipeline  307  and the second gas pipeline  308 . During aeration, if the control switch  7  is not turned on, the pressure of the second chamber  306  continues driving the first valve plug  302  to move toward the top  301   b , allowing the head of the closing portion to block up the junction (a peripheral surface  320  of the closing portion  312  clings to the inner wall  321  of the first gas pipeline  307 ) stably, until the second sealing ring  318  bears against the top  301   b  (or the second sealing ring  318  presses against the top  301   b  after being elastically deformed). When the control switch  7  is turned on, the second valve plug  402  is unscrewed, allowing the third gas pipeline  309  to be unblocked, and gas in the second chamber  306  flows to the first chamber  305  through the third gas pipeline  309 , rendering a reduction of the pressure in the second chamber  306 . The pressure of the compressed air forces the closing portion  312  of the first valve plug  302  to leave the junction, allowing the compressed air to enter the distributor  30  through the first chamber  305  and the fourth gas pipeline  310 . While the compressed air is entering the fourth gas pipeline  310  through the first chamber  305 , the whole first valve plug  302  moves toward the bottom  301   a  of the first valve seat  301 . When forces applied to the first valve plug  302  become equilibrium, the main body  311  and the closing portion  312  stay still with respect to each other. A first gap  319  for passage of the compressed air is then formed between the periphery surface  320  of the closing portion and the inner wall  321  of the first gas pipeline. While the compressed air tank stops supplying gas, the closing portion of the first valve plug blocks the junction between the first gas pipeline and the first chamber again under forces applied by the first and second elastic body, with the closing portion clinging to the inner wall of the first gas pipeline. 
         [0063]    The flux and pressure of gas in the third gas pipeline may be regulated through operation of the second control valve, which makes the closing portion move up or down and leads to change of the first gap between the inner wall of the first gas pipeline and the periphery surface of the closing portion, thereby regulating the flux and pressure of gas in the fourth gas pipeline. 
         [0064]    The first, second and third elastic bodies may be for example a spring, or an elastic sleeve, clips, or other components capable of deforming expansively or elastically along the sliding direction of the first valve plug. 
         [0065]    With such a pressure reducing valve, compressed air in the compressed air tank is output to the distributor after the air pressure is regulated. The second elastic body  313  acts as a buffer effectively reducing a rigid strike force between the first valve plug  302  and the first valve seat  301 , and meanwhile improving the air tightness provided by the closing portion  312  to the first gas pipeline  307 . Since the second gas pipeline  308  has a cross section area less than that of the third gas pipeline  309 , control on the whole gas path of the control valve  300  can be achieved, and meanwhile a flux can be amplified so as to improve precision of control. 
         [0066]    When two distributors are provided, two pressure reducing valves are provided corresponding to the two distributors and controlled by the same control switch. In this situation, as shown in  FIG. 19 , the second transmission mechanism comprises two driven pulleys separately driving the second valve plugs of the two pressure reducing valves. In other examples, more than two pressure reducing valves in series may be provided in order to achieve multistage control of the compressed air input to the gas distributor. 
         [0067]    In addition, as shown in  FIG. 16 , the pressure reducing valve may be arranged wholly in heat exchange medium  600  which exchanges heat with the gas in the pressure reducing valve so that the gas is output via a distributor after being heated. The heat exchange medium  600  is used as the circulating medium of a cooler  700  of the refrigeration air-conditioning, and is cooled after being exchanged heat with the gas in the pressure reducing valve. The cooled heat exchange medium circulates in the cooler  5  so that the temperature of ambient air is reduced. The heat exchange medium may be for example antiseptic, un-volatile coolant with good cooling effect. 
         [0068]      FIGS. 20-23  illustrate another embodiment of the wind resistance engine of the motor vehicle. The wind resistance engine  3  comprises a casing  801 , an impeller chamber  802  enclosed by the casing  801 , an auxiliary power output shaft  130  and a plurality of sets of impellers  804 . Each set of impellers  804  at least comprises a plurality of impellers each of which is fixed on the auxiliary power output shaft  130  and the impellers are staggered. The impeller chamber  802  has an air intake  805  for receiving front resistance fluid generated when the motor vehicle is running. The air intake  805  is a trumpet-type inlet with a bigger external opening and a smaller internal opening. Each set of impellers  804  are located in the air intake  805  and the diameters thereof decrease in turn toward the interior of the air intake. The auxiliary power output shaft  130  is coaxial with the primary power output shaft  120  of the compressed air engine  4 . A second clutch  111  is provided between the primary power output shaft  120  and the auxiliary power output shaft  130 . In addition, the impeller chamber has one first exhaust port  806  and two second exhaust ports  807  arranged symmetrically. The first exhaust port  806  is located at the side of the casing  801  and at the back of the impellers  804 . The air intake  805  is coaxial with the auxiliary power output shaft  130 . The axis of the first exhaust port  806  forms an angle with that of the auxiliary power output shaft  130 . The second exhaust ports  807  are located at the ends of the casing  801  and at the back of the impellers  804 . The axis of the second exhaust port  807  forms an angle with that of the auxiliary power output shaft  130 . The structure of the compressed air engine is to the same as that described previously. 
         [0069]    In the starting stage, the second clutch  111  disengages and the primary power output shaft  120  disconnects from the auxiliary power output shaft  130 . The compressed air engine  4  directly drives the drive train of the motor vehicle and does not need to drive the impellers of the wind resistance engine  3  to rotate so that the starting load is effectively reduced. When the motor vehicle is in motion, the third clutch engages and the primary power output shaft  120  is power connected to the auxiliary power output shaft  130 . Each set of impellers is driven by external wind resistance airflow that the motor vehicle encounters to rotate, and the impellers drive the auxiliary power output shaft  130  to rotate. The power of the auxiliary power output shaft  130  is transferred to the drive train of the motor vehicle via the primary power output shaft  120 . 
         [0070]    Since the primary power output shaft  120  is coaxial with the auxiliary power output shaft  130 , it is not necessary to reverse the power of the auxiliary power output shaft to output so that the structure is simplified, the power drive line is shortened and energy is saved. Since a plurality of sets of impellers  804  are used, the resistance fluid in front of the motor vehicle may be utilized more effectively. 
         [0071]    A compressed air supply system comprises a compressed air tank, a pressure reducing valve, a heat exchanger and an output pipeline. The output of the compressed air tank is connected to the pressure reducing valve via the pipeline. The working gas, outputted by the pressure reducing valve where the gas pressure is reduced, enters the output pipeline. The heat exchanger which is used to heat the pressure reducing valve comprises a container filled with coolant, and the pressure reducing valve is arranged in the coolant. The compressed air supply system further comprises a cooler and a first circulating pump. The container, the cooler and the first circulating pump communicate with each other and use the coolant as medium to form a circulating cooling system. The system exchanges heat with ambient air through the cooler. The heat exchanger comprises a heater for heating the output pipeline. The compressed air supply system further comprises a radiator and a second circulating pump. The heater, the cooler and the second circulating pump communicate with each other to form a circulating radiation system. The system exchanges heat with ambient air through the radiator. A compressed air motor vehicle refrigeration system comprises a compressed air tank, a pressure reducing valve and a container filled with coolant. The working gas outputted by the pressure reducing valve where the pressure is reduced enters the output pipeline. The pressure reducing valve is arranged in the coolant. The container, the cooler and the first circulating pump communicate with each other and use the coolant as medium to form a circulating cooling system. The system exchanges heat with ambient air through the cooler. The pressure reducing valve may be the one as shown in  FIGS. 2-4 ,  FIG. 17  and  FIG. 18 . 
         [0072]    Although the above description makes explanation in detail for the present application in reference to preferred embodiments, the practice of the present application should not be construed to be limited to these descriptions. A person skilled in the art can make various simple deductions or replacements without departing from the spirit and concept of the present application, which should be construed to fall into the scope of the appended claims of the present application.