Abstract:
A hydrogen recirculation blower for a fuel cell vehicle includes an ejector integrated with a housing of the blower. An integrated hydrogen recirculation blower for a fuel cell vehicle includes: a blower housing including an inlet and an outlet formed on a top surface thereof; an impeller rotatably installed inside the blower housing; a motor connected to a rear end of the impeller to rotate the impeller; and an ejector formed integrally on a upper surface of the blower housing.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims under 35 U.S.C. §119(a) the benefit of Korean Patent Application No. 10-2007-0129202 filed Dec. 12, 2007, the entire contents of which are incorporated herein by reference. 
       BACKGROUND 
       [0002]    (a) Technical Field 
         [0003]    The present invention relates to an hydrogen recirculation blower for a fuel cell vehicle, in which an ejector is integrated. 
         [0004]    (b) Background Art 
         [0005]    A fuel cell for a fuel cell vehicle as a power source is configured to generate electricity by reacting oxygen in air and hydrogen as fuel. 
         [0006]    The fuel cell includes a separator, an anode, an electrolyte membrane, a cathode, a hydrogen/air/coolant circulating system, an anode flow field, a cathode flow field, and a coolant flow field. 
         [0007]    For startup of the fuel cell, hydrogen as fuel is supplied from a hydrogen tank to the anode flow field via a hydrogen supply solenoid valve and a pipe. 
         [0008]    To increase fuel efficiency, hydrogen remaining unreacted in the fuel cell is recirculated. In particular, when a hydrogen recirculation system is operated in a state where a purge valve is being closed, the unreacted hydrogen in the fuel cell moves along the pipe and enters the anode flow field via the hydrogen recirculation system and a hydrogen recirculation shut-off valve. 
         [0009]    As shown in  FIGS. 1 and 2 , conventional hydrogen recirculation systems for the fuel cell use either an ejector  101  or a blower  102 . 
         [0010]    For the ejector-only system, while its power consumption and price are low, it has drawbacks in that, if the amount of hydrogen fuel used in the fuel cell stack decreases, the performance is deteriorated. That is, it cannot guarantee the performance in a wide operation range of a vehicle. 
         [0011]    For the blower-only system, on the contrary, while it can provide a desired performance in a wide operation range of a vehicle, its power consumption and price are higher than the ejector-only system. 
         [0012]    The information disclosed in this Background section is only for enhancement of the understanding of the background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art that is already known to a person skilled in the art. 
       SUMMARY OF THE DISCLOSURE 
       [0013]    The present invention has been made in an effort to solve the above-described problems associated with prior art. The present invention is directed to an integrated hydrogen recirculation blower for a fuel cell vehicle, in which an ejector is incorporated into a blower housing. With such an arrangement, the integrated hydrogen recirculation blower can be operated in an adjustable manner depending on the vehicle output power required. Specifically, both the blower and the ejector may be operated when a high power is required, while only the blower is operated when a low power is required, thus reducing the power consumption of the blower. 
         [0014]    In one aspect, the present invention provides an integrated hydrogen recirculation blower for a fuel cell vehicle, the integrated hydrogen recirculation blower comprising: a blower housing including an inlet and an outlet formed on a top surface thereof; an impeller rotatably installed inside the blower housing; a motor connected to a rear end of the impeller to rotate the impeller; and an ejector formed integrally on a upper surface of the blower housing. 
         [0015]    In a preferred embodiment, the inlet may include a plurality of inlets. Preferably, it includes a first inlet through which new hydrogen is introduced from a hydrogen tank and a second inlet through which recirculated hydrogen is introduced from a stack outlet. Suitably, the first and second inlets may be in parallel to each other. 
         [0016]    In another preferred embodiment, the blower housing may comprise an upper housing and a lower housing, in which the first and second inlets and the outlet are formed on an upper surface of the upper housing. Preferably, the first and second inlets and the outlet may be formed in parallel to each other. 
         [0017]    In still another embodiment, the upper housing may include a substantially semicircular groove which is formed in the circumferential direction on the inside edge of the upper housing. One end of the groove is preferably in fluid communication with the second inlet and the other end of the groove preferably is in fluid communication with the outlet. The recirculated hydrogen introduced through the second inlet may move along the semicircular groove and eventually be discharged through the outlet. 
         [0018]    In yet still another embodiment, the ejector may include a large diameter portion extending upwardly from the upper surface of the blower housing and a small diameter portion extending from an end of the large diameter portion with a relatively small diameter. The large diameter portion may be furnished with a first connecting passage extending from the bottom at the center thereof, which is in communication with the first inlet, and a second connecting passage formed on the outside of the first connecting passage, which is in communication with the second inlet. The small diameter portion may comprise an ejector outlet formed inside thereof, which is connected to the first connecting passage and the second connecting passage at an end of the large diameter portion where the first connecting passage and the second connecting passage are converged together. Suitably, a check valve is provided in a connecting line connecting the second inlet and the second connecting passage. 
         [0019]    At a low output power, the check valve shuts off the second inlet and the second connecting passage to prevent the recirculated hydrogen from being introduced to the ejector so that the recirculated hydrogen is introduced through the second inlet, moved along the semicircular groove, and discharged through the outlet, and the new hydrogen is introduced through the first inlet and discharged through the first connecting passage and the ejector outlet. 
         [0020]    On the other hand, at a high output power, the check valve connects the second inlet and the second connecting passage so that the recirculated hydrogen is discharged through the second connecting passage and the ejector outlet and, at the same time, introduced through the second inlet, moved along the semicircular groove, and discharged through the outlet, and the new hydrogen is introduced through the first inlet and discharged through the first connecting passage and the ejector outlet. 
         [0021]    It is understood that the term “vehicle” or “vehicular” or other similar term as used herein is inclusive of motor vehicles in general such as passenger automobiles including sports utility vehicles (SUV), buses, trucks, various commercial vehicles, watercraft including a variety of boats and ships, aircraft, and the like. 
         [0022]    The above features and advantages of the present invention will be apparent from or are set forth in more detail in the accompanying drawings, which are incorporated in and form a part of this specification, and the following Detailed Description, which together serve to explain by way of example the principles of the present invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0023]    The above and other features of the present invention will now be described in detail with reference to certain exemplary embodiments thereof illustrated the accompanying drawings which are given hereinafter by way of illustration only, and thus are not limitative of the present invention, and wherein: 
           [0024]      FIG. 1  is a schematic diagram showing a conventional ejector type hydrogen recirculation system; 
           [0025]      FIG. 2  is a schematic diagram showing a conventional blower type hydrogen recirculation system; 
           [0026]      FIG. 3  is a schematic diagram illustrating an integrated hydrogen recirculation system according to a preferred embodiment of the present invention; 
           [0027]      FIG. 4  is an perspective view showing an external structure of an integrated hydrogen recirculation blower in accordance with a preferred embodiment of the present invention; 
           [0028]      FIG. 5  is an exploded perspective view showing an internal structure of the integrated hydrogen recirculation blower of  FIG. 4 ; 
           [0029]      FIG. 6  is another exploded perspective view showing an internal structure of the integrated hydrogen recirculation blower of  FIG. 4 ; 
           [0030]      FIG. 7  is a plan view of the integrated hydrogen recirculation blower of  FIG. 4 ; 
           [0031]      FIG. 8  is an exploded view showing the impeller and the inside of the upper housing of  FIG. 5 ; 
           [0032]      FIG. 9  is a view showing an operation state in which recirculated hydrogen flows in the upper housing of  FIG. 5  at a high output power; 
           [0033]      FIG. 10  is a graph showing a change in recirculation rate according to vehicle output power; and 
           [0034]      FIG. 11  is a graph showing a power reduction effect according to vehicle output power. 
       
    
    
       [0035]    Reference numerals set forth in the Drawings includes reference to the following elements as further discussed below: 
         [0000]    
       
         
               
               
             
           
               
                   
               
             
             
               
                 10: hydrogen tank 
                 11: fuel cell 
               
               
                 12: ejector 
                 13: ejector outlet 
               
               
                 14: blower housing 
                 14a: upper housing 
               
               
                 14b: lower housing 
                 15: impeller 
               
               
                 16: motor 
                 17: first inlet 
               
               
                 18: second inlet 
                 19: outlet 
               
               
                 20: hydrogen connecting passage 
               
               
                 21: recirculated hydrogen connecting passage 
               
               
                 22: semicircular groove 
                 23: semicircular plate 
               
               
                 24: connecting line 
                 25, 26: check valves 
               
               
                   
               
             
          
         
       
     
         [0036]    It should be understood that the appended drawings are not necessarily to scale, presenting a somewhat simplified representation of various preferred features illustrative of the basic principles of the invention. The specific design features of the present invention as disclosed herein, including, for example, specific dimensions, orientations, locations, and shapes will be determined in part by the particular intended application and use environment. 
       DETAILED DESCRIPTION 
       [0037]    Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the drawings attached hereinafter, wherein like reference numerals refer to like elements throughout. The embodiments are described below so as to explain the present invention by referring to the figures. 
         [0038]      FIG. 3  is a schematic diagram illustrating an integrated hydrogen recirculation system according to a preferred embodiment of the present invention,  FIG. 4  is an perspective view showing an external structure of the integrated hydrogen recirculation blower,  FIG. 5  is an exploded perspective view showing an internal structure of the integrated hydrogen recirculation blower of  FIG. 4 ,  FIG. 6  is another exploded perspective view showing an internal structure of the integrated hydrogen recirculation blower of  FIG. 4 ,  FIG. 7  is a plan view of the integrated hydrogen recirculation blower of  FIG. 4 , and  FIG. 8  is an exploded view showing the impeller and the inside of the upper housing of  FIG. 5 . 
         [0039]    The present invention aims at integrating an ejector  12  with a blower housing  14  to utilize advantages of the blower and the ejector  12 , thus ensuring the performance in a wide operation range and reducing the power consumption. 
         [0040]    An integrated hydrogen recirculation blower in accordance with a preferred embodiment of the present invention includes the blower housing  14  having blower inlet and outlet, the ejector  12  integrated with the blower housing  14 , an impeller  15  and a motor  16  provided inside the blower housing  14 . 
         [0041]    Preferably, the overall shape of the blower housing  14  is a cylinder. The blower housing  14  includes an upper housing  14   a  and a lower housing  14   b.  A first inlet  17 , a second inlet  18 , an outlet  19 , and an ejector outlet  13  are provided on the outer surface of the upper housing  14   a.  New hydrogen and/or recirculated hydrogen is introduced through the inlets  17  and/or  18  and discharged through the outlet  19  and/or the ejector outlet  13 . The fluid has a flow direction of “U”, in which the fluid is introduced in one direction and discharged in the other direction. 
         [0042]    Hydrogen is newly supplied from a hydrogen tank  10  through the first inlet  17 . Hydrogen is recirculated from a stack outlet through the second inlet  18 . 
         [0043]    The ejector  12  includes a large diameter portion and a small diameter portion. A hydrogen connecting passage  20  extending from the bottom of the center to the outlet direction to be connected to the first inlet  17  is provided inside the large diameter portion such that the new hydrogen is introduced through the hydrogen connecting passage  20 . Moreover, a recirculated hydrogen connecting passage  21  is provided on the outside of the hydrogen connecting passage  20  to be connected to the second inlet  18 , separately from the hydrogen connecting passage  20 , such that the recirculated hydrogen is introduced through the recirculated hydrogen connecting passage  21 . 
         [0044]    The small diameter portion extends from an end of the large diameter portion with a relatively small diameter so that the hydrogen connecting passage  20  of the large diameter portion and an end of the recirculated hydrogen connecting passage  21  are joined with each other. Accordingly, the new hydrogen and the recirculated hydrogen can be mixed and discharged through the ejector outlet  13 . 
         [0045]    The impeller  15  has a circular plate shape and is provided so as to face the inside of the upper housing  14   a.  A first semicircular groove is formed along the edge of the circular plate, and a plurality of semicircular plates  23  are formed in the circumferential direction at regular intervals in the first semicircular groove. 
         [0046]    A second semicircular groove  22  is provided in the circumferential direction on the inside edge of the upper housing  14   a  so that one end thereof is connected to the second inlet  18  and the other end is connected to the outlet  19 . 
         [0047]    The first semicircular groove of the impeller  15  and the second semicircular grove  22  formed inside the upper housing  14   a  are faced with each other to facilitate the flow of the fluid and, especially, the flow of the recirculated hydrogen is facilitated by the rotation of the semicircular plates  23  of the impeller  15 . 
         [0048]    The motor  16  is connected to a rear end of the impeller  15  and thus the impeller  15  is rotated by the operation of the motor  16 . Moreover, the rotational speed and the operation of the motor  16  are controlled by a control signal from a controller. 
         [0049]    The operation state of the integrated hydrogen recirculation blower with the above described configuration will be described below. 
         [0050]      FIG. 9  is a view showing an operation state in which recirculated hydrogen flows in the upper housing of  FIG. 5  at a high output power. 
         [0051]    First, the controller receives signals from a vehicle speed sensor and a pedal sensor and controls the operation of the integrated hydrogen recirculation blower to adjust the amount of hydrogen supplied to the fuel cell  11  according to the vehicle output power. 
         [0052]    The controller operates the blower, which can provide a desired performance in a wide operation region, at a low output power. In particular, the motor  16  of the blower is operated to rotate the impeller  15  such that the new hydrogen is introduced through the first inlet  17  and discharged to the ejector outlet  13  through the hydrogen connecting passage  20  of the ejector  12  and the recirculated hydrogen is introduced through the second inlet  18  and discharged to the outlet  19  of the blower through the semicircular groove  22  formed inside the upper housing  14   a.    
         [0053]    In this case, the recirculated hydrogen connecting passage  21  of the ejector  12  is shut off by the a check valve provided in a connecting line  24  connecting the second inlet  18  and the recirculated hydrogen connecting passage  21 , thus preventing the recirculated hydrogen from being introduced to the ejector  12 . 
         [0054]    Less amount of hydrogen supplied to the fuel cell  11  is required at the low output power than that at the high output power. Thus, at the low output power, the recirculated hydrogen can be prevented from being introduced to the ejector and recirculated hydrogen can be supplemented by the operation of the blower. 
         [0055]    Meanwhile, the recirculated hydrogen is introduced through both the blower and the ejector  12  at the high output power. In particular, the motor  16  of the blower is operated to rotate the impeller  15  such that the new hydrogen is introduced through the first inlet  17  and discharged to the ejector outlet  13  through the hydrogen connecting passage  20  of the ejector  12  and the recirculated hydrogen is introduced through the second inlet  18  and discharged to the ejector output  13  through the recirculated hydrogen connecting passage  21  of the ejector  12 . 
         [0056]    Moreover, the recirculated hydrogen is introduced through the second inlet  18  by the operation of the blower and discharged to the blower outlet  19  through the semicircular groove  22  formed inside the upper housing  14   a.    
         [0057]    In this case, it is possible to reduce the rotational speed of the blower and supplement the recirculated hydrogen at the high output power by the operation of the ejector  12 , compared with the conventional hydrogen recirculation system using only the blower. 
         [0058]    In the integrated hydrogen recirculation blower, the ejector  12  can be operated in a dual mode, and thus it is possible to reduce overall power consumption. 
         [0059]      FIG. 10  is a graph showing a change in recirculation rate according to the vehicle output power, and  FIG. 11  is a graph showing a power reduction effect according to the vehicle output power. 
         [0060]    It can be ascertained that the power consumption of the blower is reduced to 50% if the vehicle is driven with an output power of 52 kW as shown in  FIG. 11 . 
         [0061]    As described above, according to the integrated hydrogen recirculation blower for the fuel cell vehicle of the present invention, the ejector is integrated with the blower housing to utilize the advantage of the blower capable of maintaining a desired performance in a wide operation region and the advantage of the ejector having a low power consumption such that only the blower is operated at a low output and the blower and the ejector are simultaneously operated at a high output, thus reducing the power. 
         [0062]    The invention has been described in detail with reference to preferred embodiments thereof. However, it will be appreciated by those skilled in the art that changes may be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.