Abstract:
A canister for a motor vehicle is connected to a fuel tank and a throttle pipe to adsorb fuel gas containing noxious constituents, which are generated in a fuel tank. A first space and a second space, through which the fuel gas flows, are defined, the fuel gas flows in opposite directions through the respective first and second spaces, the second space is divided into space parts by a plurality of support filters, a fuel gas reducing device is installed in one space part, which is delimited by two support filters, and air flow through the fuel gas reducing device is perpendicular to air flow through the first and second spaces.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to a canister applied to a motor vehicle to reduce the discharge of fuel gas and, more particularly, to a canister for a motor vehicle which can significantly reduce the amount of discharged fuel gas. 
         [0003]    2. Description of the Prior Art 
         [0004]    As is well known in the art, a motor vehicle has a device for storing fuel gas generated in a fuel tank and then supplying the fuel gas to an engine. This device is commonly called a canister. 
         [0005]    In general, fuel to be used for driving the engine is stored in a fuel tank. In the fuel tank, as the fuel vaporizes due to environmental factors such as the surrounding temperature, fuel gas is generated. Because the fuel gas contains noxious constituents, if the noxious constituents are discharged out of the motor vehicle, air pollution and waste of fuel result. 
         [0006]    In the canister, while the engine is stopped, the fuel gas generated in the fuel tank is adsorbed and stored by activated charcoal, and then, when the engine is started, the stored fuel gas is supplied to the engine, whereby air pollution and the waste of fuel are prevented. This type of canister has been disclosed in Korean Unexamined Patent Publication Nos. 2004-90740, 2004-17053, 2003-89139 and 2001-36538. 
         [0007]      FIG. 1  is a systematic view schematically illustrating the connection between a canister  1  and a fuel tank  2 . 
         [0008]    Referring to  FIG. 1 , an inlet pipe  3  of the canister  1  communicates with the fuel tank  2 . With the engine stopped, the fuel gas generated in the fuel tank  2  is introduced into the canister  1  through the inlet pipe  3  due to the internal pressure of the fuel tank. 
         [0009]    Activated charcoal for adsorbing the fuel gas is charged in the canister  1 . The fuel gas introduced into the canister  1  through the inlet pipe  3  is adsorbed by the activated charcoal. Of course, in this case, the remnant of the fuel gas, which is not adsorbed by the activated charcoal, is discharged to the atmosphere through an outlet pipe  4  which is connected to the canister  1 . 
         [0010]    The canister  1  and a throttle pipe  6  communicate with each other via a guide pipe  5 . A control valve  7  is installed on the guide pipe  5  to control the flow of fuel gas from the canister  1  to the throttle pipe  6 . The control valve  7  is closed with the engine stopped and is opened with the engine started. 
         [0011]    When a driver starts the engine, air is supplied to the engine through the throttle pipe  6 . In this state, since the internal pressure of the throttle pipe  6  is lower than atmospheric pressure, outside air is introduced into the throttle pipe  6  through the discharge pipe  4 , the canister  1  and the guide pipe  5 . At this time, the fuel gas which is adsorbed by the activated charcoal in the canister  1  is introduced into the throttle pipe  6  along with the air flow and is supplied to the engine. 
         [0012]    The conventional canister suffers from a drawback as described below. 
         [0013]    According to recent regulations limiting the discharge of fuel gas, that is, regulations mandating a PZEV (partial zero emission vehicle), the discharge of fuel gas must not exceed 0.35 g per gallon of fuel. 
         [0014]    In this regard, the conventional canister encounters problems in that the inside structure thereof is not appropriate for accommodating various kinds of activated charcoal, and since the flow path of fuel gas is simple, fuel gas cannot be sufficiently adsorbed to the activated charcoal. That is to say, the conventional canister cannot satisfy the PZEV regulations due to its structure. 
         [0015]    Further, in order to respond to these problems, while attempts have been made to separately attach a fuel gas reducing device capable of reducing fuel gas outside the canister, in this case, a problem is caused in that, since the fuel gas reducing device, which is expensive, must be added, the manufacturing cost of the motor vehicle markedly increases. 
       SUMMARY OF THE INVENTION 
       [0016]    Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and provides a canister for a motor vehicle which can significantly reduce the amount of discharged fuel gas. 
         [0017]    In an aspect, the present invention provides a canister for a motor vehicle, connected to a fuel tank and a throttle pipe to adsorb fuel gas containing noxious constituents, which are generated in a fuel tank, wherein a first space and a second space, through which the fuel gas flows, are defined, the fuel gas flows in opposite directions through the respective first and second spaces, the second space is divided into space parts by a plurality of support filters, a fuel gas reducing device is installed in one space part, which is delimited by two support filters, and air flow through the fuel gas reducing device is perpendicular to air flow through the first and second spaces. 
         [0018]    According to another aspect of the present invention, activated charcoal is charged in the fuel gas reducing device. 
         [0019]    According to another aspect of the present invention, the ingredients of the activated charcoal, which is charged in the fuel gas reducing device, are different from those of activated charcoal, which is charged in the first and second spaces. 
         [0020]    According to another aspect of the present invention, BWC (Butane Working Capacity) activated charcoal is charged in the fuel gas reducing device. 
         [0021]    According to still another aspect of the present invention, the fuel gas reducing device has a fuel gas reducing block, which is filled with the activated charcoal, and a bracket for holding the fuel gas reducing block, the fuel gas reducing block has windows for air flow on opposite sides thereof, and the bracket has upper and lower horizontal plates which are formed to be long in opposite directions. 
         [0022]    According to a still further aspect of the present invention, the activated charcoal is charged in the fuel gas reducing block. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0023]    The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which: 
           [0024]      FIG. 1  is a schematic view illustrating the connection between a canister and a fuel tank; 
           [0025]      FIG. 2  is a perspective view of a canister with a fuel gas reducing device in accordance with an embodiment of the present invention; 
           [0026]      FIG. 3  is an exploded perspective view of the canister with a fuel gas reducing device shown in  FIG. 2 ; 
           [0027]      FIG. 4  is a projection view of the canister with a fuel gas reducing device shown in  FIG. 2 ; 
           [0028]      FIG. 5  is a cross-sectional view of the canister with a fuel gas reducing device shown in  FIG. 2 ; 
           [0029]      FIG. 6  is a perspective view of a fuel gas reducing device; 
           [0030]      FIG. 7  is an exploded perspective view of the fuel gas reducing device; 
           [0031]      FIG. 8  is a view illustrating the use of the canister with a fuel gas reducing device; 
           [0032]      FIGS. 9A and 9B  are projected perspective views illustrating the flow of fuel gas in the canister with a fuel gas reducing device. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0033]    Reference will now be made in greater detail to a preferred embodiment of the invention, an example of which is illustrated in the accompanying drawings. Wherever possible, the same reference numerals will be used throughout the drawings and the description to refer to the same or like parts. 
         [0034]      FIGS. 2 through 5  illustrate a canister  1  with a fuel gas reducing device  10  in accordance with an embodiment of the present invention, wherein  FIG. 2  is a perspective view,  FIG. 3  is an exploded perspective view,  FIG. 4  is a projection view, and  FIG. 5  is a cross-sectional view. 
         [0035]    The canister  1  includes a canister body  11  and a bottom plate  12  which is coupled to the lower end of the canister body  11 . In the canister body  11 , a fuel gas reducing device  10 , a diffusion trap  20 , a purge filter  30 , a support filter  40 , activated charcoal  50 , a strainer  60 , and elastic members  70  are disposed. 
         [0036]    The canister body  11  is open at the lower end thereof and has a trapezoidal shape which is gradually narrow from the lower end to the upper end thereof. 
         [0037]    A vertical partition wall  111  is formed in the canister body  11  to divide the inside space of the canister  11  along the vertical direction into two spaces, that is, a first space  112  and a second space  113 . A tank port  11   a  for the introduction of the fuel gas generated in a fuel tank  2  (see  FIG. 1 ) and a purge port  11   b  for the discharge of adsorbed fuel gas into a guide pipe  5  are provided to the upper end of the first space  112 . An air port  11   c  for the suction and discharge of air is provided at the center portion on the upper end of the second space  113 . 
         [0038]    An air gap  114  is formed in the upper end of the canister body  11  which corresponds to the first space  112 , and the diffusion trap  20  is arranged below the air gap  114 . The diffusion trap  20  has the shape of a rectangular block which is open at the upper end thereof, and a plurality of holes  20   a  is defined through the bottom of the diffusion block  20 . A fastening hole  20   b  for mounting the purge filter  30  is defined through the bottom of the diffusion block  20  at a position which corresponds to the purge port  11   b.    
         [0039]    The air gap  114  and the diffusion trap  20  function to allow the fuel gas, introduced into the canister  1  through the tank port  11   a , to pass through the layer of the activated charcoal  50  over as wide a range as possible. 
         [0040]    A first support filter  41  is arranged below the diffusion trap  20 . A hole  41   a  is defined through the first support filter  41  to correspond to the mounting position of the purge filter  30 . The first support filter  41  functions to prevent the activated charcoal  50  charged in the first space  112  from being released to the outside. 
         [0041]    The purge filter  30  has a cylindrical configuration and is formed of non-woven fabric, etc. The purge filter  30  functions to filter fine dust etc. from the fuel gas which is supplied into an engine room through the purge port  11   b.    
         [0042]    Also, a second support filter  42  is arranged adjacent to the lower end of the first space  112 . The activated charcoal  50  is charged between the first and second support filters  41  and  42 . Here, for example, 2GK-N is used as the activated charcoal  50 . Like the first support filter  41 , the second support filter  42  functions to prevent the activated charcoal  50  charged in the first space  112  from being released to the outside. 
         [0043]    A third support filter  42  for preventing the activated charcoal  50  from being released to the outside is arranged adjacent to the lower end of the second space  113 . The strainer  60  is installed below the second and third support filters  42  and  43  to entirely support the activated charcoal  50  which is charged in the first and second spaces  112  and  113 . The strainer  60  is elastically supported relative to the bottom plate  12  by the elastic members  70 . 
         [0044]    The second space  113  is divided into a plurality of space parts by third through sixth support filters  43  through  46 . Here, for example, 2GK-N activated charcoal  50  is charged between the third and fourth support filters  43  and  44 , and, for example, BAX1110 activated charcoal  50  is charged between the fourth and fifth support filters  44  and  45 . The fuel gas reducing device  10  is mounted between the fifth and sixth support filters  45  and  46 . The filling positions of the 2GK-N and the BAX1110, used as the activated charcoal  50 , and the mounting position of the fuel gas reducing device  10  can be changed among the space parts which are divided by the third through sixth support filters  43  through  46 . 
         [0045]    The sixth support filter  46  is installed to be spaced apart from the air port  11   a  due to the presence of an air gap  115  which is formed in the upper end of the canister body  11 . This is to ensure that the suction and discharge of air through the air port  11   c  can easily occur. 
         [0046]      FIG. 6  is a perspective view illustrating the outer appearance of the fuel gas reducing device  10 , and  FIG. 7  is an exploded perspective view of the fuel gas reducing device  10 . 
         [0047]    The fuel gas reducing device  10  includes a fuel gas reducing block  110  and a bracket  120  for holding the fuel gas reducing block  110 . 
         [0048]    The fuel gas reducing block  110  has windows  110   a  for allowing air flow on opposite sides thereof. The windows  110   a  are installed perpendicular to the flowing direction of the fuel gas in the canister body  11 , that is, perpendicular to the flow path of the fuel gas which is introduced through the tank port  11   a  and discharged through the air port  11   c . For example, BWC activated charcoal  50  is charged in the fuel gas reducing block  110 . 
         [0049]    The bracket  120  has a vertical plate  120   a  and upper and lower horizontal plates  120   b  and  120   c  which are integrally coupled to the vertical plate  120   a . When viewed in its entirety, the bracket  120  has the shape of a clockwise 90°-rotated U. In particular, the upper horizontal plate  120   b  is formed to extend longer on one side thereof (the right side in the drawing) than the lower horizontal plate  120   c  in a manner such that the end thereof is brought into contact with one inner surface portion of the canister body  11 , and the lower horizontal plate  120   c  is formed to extend longer on the other side thereof (the left side in the drawing) than the upper horizontal plate  120   b  in a manner such that the end thereof is brought into contact with another inner surface portion of the canister body  11 . 
         [0050]    According to this, the fuel gas, which has passed through the fifth support filter  45 , flows through the space which is defined between the fuel gas reducing block  110  and one inner surface portion of the canister body  11 , and is then introduced into the fuel gas reducing block  110  through one window  110   a  of the fuel gas reducing block  110 . Thereafter, the air, which is discharged through the other window  110   a  of the fuel gas reducing block  110 , flows upwards through the space which is defined between the fuel gas reducing block  110  and another inner surface portion of the canister body  11 , and is then discharged into the air port  11   c  through the sixth support filter  46 . 
         [0051]    Further, outside air, which enters the canister body  11  through the air port  11   c , passes through the sixth support filter  46 ; flows through the space which is defined between the fuel gas reducing block  110  and another inner surface portion of the canister body  11 , and is then introduced into the fuel gas reducing block  110  through the other window  110   a  of the fuel gas reducing block  110 . Thereafter, the air, which is discharged through one window  110   a  of the fuel gas reducing block  110 , flows downwards through the space which is defined between the fuel gas reducing block  110  and one inner surface portion of the canister body  11 , and then passes through the fifth support filter  45 . 
         [0052]    The sixth support filter  46  is arranged to be spaced apart from the air port  11   c  by a predetermined interval due to the presence of the air gap  115 . This is to ensure that air flow through the air port  11   c  can easily occur. 
         [0053]    Hereafter, the operation of the canister with a fuel gas reducing device, constructed as mentioned above, will be described with reference to  FIGS. 8 ,  9 A and  9 B.  FIG. 8  is a systematic view schematically illustrating the connection between the canister  1  with the fuel gas reducing device  10  according to the present invention and the fuel tank  2 , and  FIGS. 9A and 9B  are projected perspective views explaining the fuel gas flow in the canister  1  with the fuel gas reducing device  10 . 
         [0054]    As described with reference to  FIG. 1 , when the engine is stopped, the liquid fuel stored in the fuel tank  2  vaporizes under the influence of the surrounding temperature, etc., and fuel gas is generated. As the fuel gas is generated, the internal pressure of the fuel tank  2  increases, and the vaporized fuel gas is introduced by the internal pressure into the tank port  11   a  of the canister  1  through an inlet pipe  3 , which is connected to the fuel tank  2 . 
         [0055]    As in the conventional canister, the fuel gas introduced into the tank port  11   a  flows downwards through the first space  112 , which is defined in the canister  1 . Then, the fuel gas is introduced into the second space  113  through the second support filter  42 , the inside space of the bottom plate  12 , and the third support filter  43 , and flows toward the fuel gas reducing device  10 . 
         [0056]    Meanwhile, as described above, the fuel gas reducing device  10  is formed with the windows  110   a  on opposite sides thereof, and the upper and lower horizontal plates  120   b  and  120   c  extend long distances in opposite directions and are brought into contact with the opposite inner surface portions of the canister body  11 . 
         [0057]    Therefore, the fuel gas, which flows upward through the second space  113 , is changed in its flow direction at the fuel gas reducing device  10  so as to be perpendicular to the previous flow direction. Then, after the fuel gas flows through the inside of the fuel gas reducing device  10  in the horizontal direction, the fuel gas is changed again in its flow direction by 90° and discharged to the outside through the air port  11   c.    
         [0058]    When a driver starts the engine, as the pressure inside the throttle pipe  6  decreases, the control valve  7  is converted to an open state. Hence, as mentioned with respect to  FIG. 1 , outside air is introduced into the canister  1  through a discharge pipe  4  and the air port  11   c , and flows into the throttle pipe  6  through the purge port  11   b  and a guide pipe  5  to thus be supplied to the engine. 
         [0059]    In this procedure, air flow in the canister  1  occurs in a direction opposite that of the above-described procedure. In other words, the air introduced into the canister  1  through the air port  11   c  flows through the fuel gas reducing device  10  in the horizontal direction, passes through the second space  113 , the inside space of the bottom plate  12  and the first space  112 , and is discharged through the purge port  11   b.    
         [0060]    In the present embodiment, due to the use of the fuel gas reducing device  10 , the air flow in the canister  1  cannot but be limited. Namely, in the conventional canister, the fuel gas, which is introduced into the canister through the tank port  11   a , flows straight through the first space  112  and the second space  113  defined in the canister  1  and is discharged through the air port  11   c . However, in the present embodiment, air flow is changed by 90° by the fuel gas reducing device  10 , which is installed in the second space  113 , by which smooth air flow is restrained. If the air flow in the canister  1  is restrained, the contact time between the activated charcoal  50  charged in the canister  1  and the fuel gas is extended, and according to this, the adsorption efficiency of the fuel gas by the activated charcoal  50  is improved. 
         [0061]    Also, in the present embodiment, as the activated charcoal  50 , which is charged between the first through fifth support filters  41  through  45  and in the fuel gas reducing device  10 , for example, 2GK-N, BAX1110 and BWC are used. That is to say, various kinds of activated charcoal can be used together. If various kinds of activated charcoal are used, since the noxious substances not adsorbed by a certain kind of activated charcoal can be adsorbed by another kind of activated charcoal, the kinds and the amounts of the noxious gas discharged through the air port  11   c  can be remarkably reduced. 
         [0062]    In the present embodiment, due to the fact that various kinds of activated charcoal are used and the fuel gas reducing device  10  is adopted, the flow of fuel gas is restrained, and the amount of fuel gas discharged from the canister  1  can be considerably reduced below the level which is required by the PZEV regulations. 
         [0063]    As is apparent from the above description, according to the present invention, it is possible to realize a canister with a fuel gas reducing device which can significantly reduce the discharge of fuel gas. 
         [0064]    Although a preferred embodiment of the present invention has been described for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims. 
         [0065]    For example, while it was described in the above embodiment that one fuel gas reducing device  10  is installed in the canister  1 , it is conceivable that a plurality of fuel gas reducing devices  10  can be installed in the canister  1 . Also, the installation position of the fuel gas reducing device  10  is not limited to the specified location, and therefore, the fuel gas reducing device  10  may be located in the first space  112  of the canister  1 .