Abstract:
A canister for the recovery of evaporated fuel in a fuel tank of a vehicle is positioned in a central region of a vehicle. The vehicle body frame includes left and right side frames attached with a plurality of cross members. The canister is positioned behind a central cross member at a side opposite of an exhaust pipe running from the vehicle engine toward the rear of the vehicle. By attaching the canister in this location, a vapor pipe connecting the canister with the fuel tank is shortened, resulting in a more adequate recovers of evaporated fuel. Additionally, a canister placed in this location, is made larger, further increasing the adequacy of evaporated fuel recovery. Furthermore, as opposed to conventional canisters being located in the engine compartment, a canister located behind the central cross member is not effected by warming caused by the engine. The result is a canister having excellent performance in the recovery of evaporated fuel from the fuel tank of a vehicle.

Description:
BACKGROUND TO THE INVENTION 
     The present invention relates to a canister attachment construction of a vehicle. In particular, the present invention relates to a canister attachment construction, wherein the canister is installed on the right side of the vehicle in a region surrounded by a central cross member, which is positioned at approximately the central region of the vehicle frame, a cross member that is positioned behind this central cross member, and a side frame. The present inventions relates to a canister attachment construction wherein the length of the vapor pipe, which connects the canister to the fuel tank, is shortened. Furthermore, the present invention relates to a canister attachment construction wherein the canister is made larger in order to ensure an adequate adsorption amount. Since the canister of the present invention is not placed in the engine compartment of the vehicle, the engine compartment is simplified, and there is no risk of reduced adsorptive function due to warming of the canister. 
     A conventional vehicle has a canister to sorb and retain evaporated fuel generated inside a fuel tank. The canister supplies this retained evaporated fuel to the intake system of an internal combustion engine. 
     The canister is controlled so that, for example, when the internal combustion engine is stopped, the canister sorbs and retains evaporated fuel which is generated inside a fuel tank. In addition, when the internal combustion engine is running, the evaporated fuel that has been sorbed and retained is released supplied to the intake system of the internal combustion engine. 
     A conventional vehicle canister attachment construction described above is disclosed in Japanese Laid-Open Patent Publication No. 5-193522. In the under body construction of the car disclosed in this publication, a transfer and a canister are disposed underneath the floor of the car body. The canister is placed along the retreating path of the transfer. A support construction is used, in which, at the time of a collision of the vehicle, the canister is displaced to the side of the retreating pathway of the transfer. A large volume canister, which uses the open space in back, is installed on the transfer underneath the floor of the car body. 
     In addition, another conventional canister attachment construction is disclosed in Japanese Laid-Open Patent Publication Number 8-142693. In the canister attachment construction disclosed in this publication, a canister is filled with adsorbent to sorb evaporated fuel generated inside a fuel tank. The canister is disposed at an approximately central region of a cross member that connects between the rear side members on either side of the vehicle. The canister is attached at a part with the least vibration, to prevent the wearing of the adsorbent within the canister. 
     In addition, another conventional canister attachment construction is disclosed in Japanese Laid-Open Patent Publication Number 8-230493. In this publication, there is disclosed a evaporated fuel treatment device for a vehicle, wherein a vehicle is equipped with a frame, which constructs the car body. The frame includes a pair of right and left side members, which construct the rear part of the car body. A cross member connects both side members together. An exhaust pipe, passing exhaust gas emitted from the engine, is positioned near the side members and cross member. A canister is disposed in the space surrounded by the side members, cross member, and exhaust pipe. Fuel is efficiently released from the adsorbent within the canister. 
     In addition, another conventional canister attachment construction is disclosed in Japanese Examined Patent Publication Number 2535338. The placement construction of the canister disclosed in this publication is in a region surrounded by right and left side members, the upright part of the rear floor panel, and a placing member in the car crosswise direction of a rear suspension. The canister is disposed on the opposite side of the exhaust tube, which has been displaced to one side of the car in the crosswise direction. 
     In addition, another conventional canister attachment construction is disclosed in Japanese Examined Utility Model Publication Number 6-8897. In the fuel tank canister disclosed in this publication, the fuel tank as well as the canister, which is attached and supported via brackets near the fuel tank, are placed on the underside of the floor within an area surrounded by a pair of rear frames, which are placed on the underside of the floor at the rear of a vehicle. A pair of cross members are placed between the rear frames. This arrangement is advantageous for protecting the canister. 
     In addition, another conventional canister attachment construction is disclosed in Japanese Laid Open Utility Model Publication 2557012. In the car canister attachment construction of this publication, the canister is attached to a spare tire mount at the rear of the car body. A pipe connected to the canister extends in the cross direction of the car body from the canister, in the forward direction of the car body along the rear side frame. The pipe is anchored to the spare tire mount by a first fastening member. At a certain distance in the front-rear direction of the car body, the pipe is fastened to the rear side frame or to a car body member near it by a second fastening member and a third fastening member. Between the second and third fastening members, a bending part is formed in the down direction of the car body. There is no danger of the pipe falling off of the canister while the vehicle is moving. 
     Referring to FIGS. 5,  6  and  7 , conventional canister attachment constructions of a vehicle include a canister  124 , 224  attached via brackets to front wheel housing panels  152 , 252  inside an engine compartment on the vehicle front side. 
     A car body frame  104  of vehicle  102  has a construction including right and left side frames  110 - 2  (the disclosure of the left side frame is omitted). A subframe  112  is positioned between side frames  110 - 2 . A plurality, preferably five, cross members  114 - 3 ,  114 - 4 , and  114 - 5  (the disclosure of first and second cross members is omitted) are positioned between side frames  110 - 2 . 
     On one side of the vehicle, preferably the left side, an exhaust pipe extends from the vehicle front side towards the vehicle rear side. A fuel tank  128  is positioned on the vehicle rear side. On the other side of the vehicle, preferably the vehicle right side, a vapor pipe  154  connects fuel tank  128  to canisters  124 ,  224 . A fuel supply pipe  134  supplies fuel from fuel tank  128  to an injector (not shown). A fuel return pipe  136  returns fuel from the injector to fuel tank  128 . 
     For the conventional canister described above, there are various constructions depending on the adsorption amount. For example, referring specifically to FIG. 6, there is a canister construction where the top of canister  124  connects to vapor pipe  154 , which connects fuel tank  128  with canister  124 . A purge hose connects canister  124  with the intake system of the internal combustion engine. The bottom of canister  124  connects to a canister air hose  132 . 
     Referring specifically to FIG. 7, there is a canister construction where the top of canister  224  connects to a purge hose, which connects canister  224  with the intake system of the internal combustion engine. A canister air hose  232  also connects with the top of canister  224 . The bottom of canister  224  connects to a vapor pipe, which connects the fuel tank with canister  224 . 
     As a result, the length of the vapor pipe, which connects the fuel tank with the canister, becomes long. This construction makes it difficult for the evaporated fuel generated inside the fuel tank to be adequately sorbed and retained by the canister. This construction also makes it easier for the evaporated fuel to be released into the atmosphere when refueling and the like. 
     In addition, by attaching the canister to the inside of the engine room of a vehicle, the atmospheric temperature is raised, and the adsorptive performance of the canister may be reduced. 
     Furthermore, for example, when an external force acts from the front side of the vehicle, such as during a front end collision, the internal combustion engine moves towards the rear of the vehicle due to this external force. In order to prevent the front wheel housing panel from being pushed by the internal combustion engine and breaking the canister, there needs to be a procedure for strengthening the canister perimeter members or a procedure for having some other form of reinforcing members. This increases the overall manufacturing costs of the vehicle. 
     OBJECTS AND SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide a canister attachment construction which overcomes the foregoing problems. 
     It is a further object of the present invention to provide a canister attachment construction wherein the length of a vapor pipe connecting the canister to the fuel tank of the vehicle is shortened. 
     It is another object of the present invention to provide a canister attachment construction wherein the canister is made larger in order to ensure an adequate fuel vapor adsorption. 
     It is yet another object of the present invention to provide a canister attachment construction wherein the canister is placed outside of the engine compartment of the vehicle, thereby minimizing the risk of reduced adsorptive function due to warming of the canister. 
     In order to eliminate the above problems, the present invention provides a canister attached to a vehicle. The canister is placed between a vapor pipe, which connects to the inside of a fuel tank of the vehicle, and a purge hose, which connects to an intake system of an internal combustion engine. The canister, by way of the vapor pipe, sorbs and retains evaporated fuel generated inside the fuel tank. The sorbed and retained fuel is released by air and supplied to the intake system of the internal combustion engine. A car body frame of the vehicle comprises a left and a right side frames and a plurality of cross members, which are placed between the side frames sequentially from the vehicle front to the vehicle rear. On one side of the vehicle, an exhaust pipe extends from the vehicle front to the vehicle rear. The canister is installed on the side opposite to the exhaust pipe on the vehicle. The canister is surrounded by a central cross member, which is positioned at an approximately central region of the car body frame, a cross member positioned behind the central cross member, and the side frame. 
     Briefly stated, the present invention provides a canister for the recovery of evaporated fuel in a fuel tank of a vehicle which is positioned in a central region of a vehicle. The vehicle body frame includes left and right side frames attached with a plurality of cross members. The canister is positioned behind a central cross member at a side opposite of an exhaust pipe running from the vehicle engine toward the rear of the vehicle. By attaching the canister in this location, a vapor pipe connecting the canister with the fuel tank is shortened, resulting in a more adequate recovers of evaporated fuel. Additionally, a canister placed in this location, is made larger, further increasing the adequacy of evaporated fuel recovery. Furthermore, as opposed to conventional canisters being located in the engine compartment, a canister located behind the central cross member is not effected by warming caused by the engine. The result is a canister having excellent performance in the recovery of evaporated fuel from the fuel tank of a vehicle. 
     According to an embodiment of the present invention, there is provided a canister attachment construction, comprising: a canister attached to a vehicle; a vehicle body frame including a left side frame and a right side frame; a plurality of cross members spanning between the left side frame and the right side frame; a vapor pipe connecting a fuel tank of the vehicle with the canister; a purge hose connecting the canister with an engine of the vehicle; adsorbing means inside the canister for adsorbing and retaining evaporated fuel generated inside the fuel tank; the canister being positioned under the vehicle in a region defined by the left side frame and the right side frame; and the region being to a rear of a central cross member of the plurality of cross members. 
     The above, and other objects, features and advantages of the present invention will become apparent from the following description read in conjunction with the accompanying drawings, in which like reference numerals designate the same elements. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a schematic plan view of the car body frame of the vehicle of the embodiment of the present invention. 
     FIG. 2 is a schematic enlarged perspective view of the attachment of the canister. 
     FIG. 3 is a schematic plan view of the car body frame showing a first special construction of the present invention. 
     FIG. 4 is a schematic enlarged cross-section of the third cross member showing a second special construction. 
     FIG. 5 is a schematic enlarged perspective view of the canister attachment of the prior art. 
     FIG. 6 is a schematic enlarged perspective view showing the canister attachment of a first example. 
     FIG. 7 is a schematic enlarged perspective view showing the canister attachment of a second example. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     According to the canister attachment construction of the present invention, a canister is preferably attached to a car body frame of a vehicle on the vehicle right side, in a region surrounded by a central cross member, positioned approximately in the center of the car body frame of the vehicle, a cross member positioned behind this central cross member, and a side frame. 
     Referring to FIGS. 1 and 2, a vehicle  2  includes a car body frame  4  mounted on a left front wheel  6 - 1 , a right front wheel  6 - 2 , a left rear wheel  8 - 1 , and a right rear wheel  8 - 2 . 
     Car body frame  4  of vehicle  2  includes a left side frame  10 - 1  and a right side frame  10 - 2  having a sub-frame  12  placed between left and right side frames  10 - 1  and  10 - 2 . A plurality of cross members  14  are placed between left and right side frames  10 - 1  and  10 - 2 . Preferably, five cross members  14  are included in vehicle  2 , numbered sequentially from the vehicle front side to the vehicle rear side as  14 - 1  through  14 - 5 . A tail member  16  spans left and right side frames  10 - 1  and  10 - 2  at the rear side of vehicle  2 . 
     An exhaust pipe  18  is positioned on one side of vehicle  2 , preferably on the vehicle left side. Exhaust pipe  18  extends from the vehicle front side towards the vehicle rear side. 
     An upstream end of exhaust pipe  18  connects with an exhaust system of an internal combustion engine (may be noted as “E/G”), which has an attached transmission (not shown). The internal combustion engine is placed inside an engine compartment  20  which is at the front side of vehicle  2  in front of third cross member  14 - 3 . The downstream end of exhaust pipe  18  is positioned at the vehicle rear side. Exhaust pipe  18  has a muffler  22  at an intermediate position. 
     In this construction, canister  24  is placed on the side of vehicle  2  opposite exhaust pipe  18 , preferably, on the vehicle right side. Canister  25  is positioned in a region surrounded by central cross member  14 - 3 , which is positioned in an approximately central region of car body frame  4  of vehicle  2 , cross member  14 - 4 , positioned behind central cross member  14 - 3 , and left and right side frames  10 - 1  and  10 - 2 . 
     Described in detail, cross member  14  includes five, first through fifth, cross members  14 - 1 ,  14 - 2 ,  14 - 3 ,  14 - 4 , and  14 - 5  (disclosure of first and second cross members  14 - 1  and  14 - 2  are omitted), which are placed sequentially from the vehicle front side to the vehicle rear side. Central cross member  14 - 3  is positioned in an approximately central region of car body frame  4  of vehicle  2 . The cross member positioned behind third cross member  14 - 3  is fourth cross member  14 - 4 . 
     The internal combustion engine (not shown) and the transmission (not shown) are placed forward of central cross member  14 - 3 . Canister  24  is placed behind central cross member  14 - 3 . 
     On the right side of vehicle  2  and in a region surrounded by third and fourth cross members  14 - 3  and  14 - 4 , and left and right side frames  10 - 1  and  10 - 2 , canister  24  is installed by way of a canister bracket  26 . Canister  24  is separated from muffler  22  of exhaust pipe  18 . At the rear side of vehicle  2 , canister  24  is positioned forward of fuel tank  28 , which is loaded between fifth cross member  14 - 5  and tail member  16 . 
     In other words, canister bracket  26  attaches to third cross member  14 - 3  and side frame  10 - 2 . In addition, the outer dimensions of canister bracket  26  is formed larger than canister  24 . Canister  24  is supported by canister bracket  26 . 
     In addition, canister  24  has a vapor pipe (not shown), which connects to the inside of fuel tank  28 . A purge hose  30  connects with the intake system of the internal combustion engine (not shown). A canister air hose  32  introduces atmospheric air into canister  24 . 
     Purge hose  30  connects to canister  24  on the vehicle rear side. From the connecting site, purge hose  30  goes around to the side of side frame  10 - 2  on the right side of vehicle  2 . Next, purge hose  30  is placed along the inside of side frame  10 - 2  on the right side of vehicle  2 . In addition, on the inside area of side frame  10 - 2 , a fuel supply pipe  34 , which sends fuel from fuel tank  28  to an injector (not shown), and a fuel return pipe  36 , which sends fuel from the injector back to the fuel tank, are positioned. 
     The air releasing end of canister air hose  32  is inserted and connected to a region on car body frame  4  of vehicle  2  with a significant height, for example tail member  16 . 
     Furthermore, canister air hose  32  has an air filter  38  at an intermediate region. When fuel tank  28  is loaded onto the vehicle rear side, air filter  38  is placed in the region surrounded by fuel tank  28 , left side frame  10 - 1 , and fifth cross member  14 - 5 . 
     A propeller shaft  40 , a sub-frame attachment piece  42 , a body mount piece  44 , a fuel pump  46 , and an air cut valve  48 , are also included in vehicle  2 . 
     When attaching canister  24  to car body frame  4  of vehicle  2 , canister  24  is installed with canister bracket  26  on the right side of vehicle  2  in the region surrounded by third and fourth cross members  14 - 3  and  14 - 4  and left and right side frames  10 - 1  and  10 - 2 . 
     Compared to the attachment position of fuel tank  28 , which is loaded in the rear side of vehicle  2 , between fifth cross member  14 - 5  and tail member  16 , canister  24  is positioned toward the front of the attachment position of fuel tank  28 . 
     Furthermore, purge hose  30  of canister  24  connects at the vehicle rear side of canister  24 . From the connection site, purge hose  30  goes around to side frame  10 - 2 , on the right side of vehicle  2 . Purge hose  30  is then placed along the inside of side frame  10 - 2  on the right side of vehicle  2 . 
     Fuel supply pipe  34  supplies fuel from fuel tank  28  to an injector (not shown). Fuel returning pipe  36  returns fuel from the injector to fuel tank  28 . Both fuel supply pipe  34  and fuel return pipe  36  are placed in the interior region of right side frame  10 - 2 . 
     Furthermore, the end of canister air hose  32  that is open to the atmosphere is inserted and connected to a region on car body frame  4  of vehicle  2  with a significant height, for example tail member  16 . 
     Canister air hose  32  has an air filter  38  at an intermediate position. When fuel tank  28  is loaded onto the vehicle rear side, air filter  38  is placed in the region surrounded by fuel tank  28 , left side frame  10 - 1 , and fifth cross member  10 - 5 . 
     Canister  24  is installed with canister bracket  26  on the right side of vehicle  2  in a region surrounded by third and fourth cross members  14 - 3  and  14 - 4 , and left and right side frames  10 - 1  and  10 - 2 . The pipe length of the vapor pipe, which connects canister  24  and fuel tank  28 , is shortened. The evaporated fuel generated inside fuel tank  28  is more readily sorbed and retained by canister  24 . In addition, when refueling and the like, the evaporated fuel is not easily released into the atmosphere. This construction has practical advantages. 
     Furthermore, the space in which canister  24  is installed is large compared to that of the prior art. As a result, canister  24  can be made large in order to increase the adsorption amount. An adequate adsorption amount is ensured, and there is improved ease of use. 
     Furthermore, because canister  24  is not installed inside engine compartment  20  of vehicle  2 , the inside of engine compartment  20  is simplified. In addition, there is no danger of canister  24  being heated, resulting in reduced adsorptive capability. This is a practical advantage. 
     Furthermore, if, for example, an external force acts from the front of the vehicle, even if the internal combustion engine is moved towards the vehicle rear due to the external force, there is no danger of canister  24  being pushed and breaking due to the external force. A procedure for preventing the breaking of the canister, or in other words a procedure for strengthening the canister perimeter members or a procedure for having other reinforcing members, becomes unnecessary. Low costs are maintained, resulting in a significant economic advantage. Even if an external force acts from the vehicle rear side, canister  24  is interposed between right rear wheel  8 - 2  and the rear differential (not shown), minimizing the danger of canister  24  breaking. 
     Vehicle  2  has the internal combustion engine and transmission placed in front of central cross member  14 - 3 , and canister  24  placed behind central cross member  14 - 3 . As a result, even if an external force acts from the vehicle front side, and even if the internal combustion engine moves towards the vehicle rear due the external force, third cross member  14 - 3  hinders the movement of the internal combustion engine. There is no danger of canister  24  being pushed and broken by the internal combustion engine. This is a practical advantage. 
     Furthermore, when supporting canister  24 , canister bracket  26 , attached to central cross member  14 - 3  and side frame  10 - 2 , has an outer measurement that is greater than canister  24 . As a result, because the strength of canister bracket  26  is high, when an external force acts from the vehicle front side, the breaking of canister  24  is prevented. The occupied area of canister bracket  26  is large, thereby preventing damage to canister  24  from flying rocks from below. 
     Furthermore, by inserting and connecting the end that is open to the air of canister air hose  32  to a region which is high on car body frame  4  of vehicle  2 , for example, to tail member  16 , even though water may enter into right and left side frames  10 - 1  and  10 - 2 , there is no danger of water entering inside tail member  16 . The entering of water and dust into canister  24  is reliably prevented. 
     Furthermore, by placing air filter  38  in a region surrounded by fuel tank  28 , left side frame  10 - 1 , and fifth cross member  14 - 5 , air filter  38  and tail member  16  are connected by a straight hose. The piping is simplified, and this is a practical advantage. 
     Having described preferred embodiments of the present invention with reference to the accompanying drawings, it is to be understood that the invention is not limited to those precise embodiments, and that various changes and modifications may be effected therein by one skilled in the art without departing from the scope or spirit of the invention as defined in the appended claims. 
     For example, in one embodiment of the present invention, when attaching canister  24  to car body frame  4  of vehicle  2 , canister  24  is installed on the right side of the vehicle, in a region surrounded by third and fourth cross members  14 - 3  and  14 - 4  and left and right side frames  10 - 1  and  10 - 2 . However, referring to FIG. 3, as shown by the alternating long and short dashed line, canister  24 A can have a special construction where it is installed on the right side of the vehicle, in a region surrounded by fourth and fifth cross members  14 - 4  and  14 - 5  and left and right side frames  10 - 1  and  10 - 2 . 
     In this case, similar to the embodiment described above, the pipe length of the vapor pipe, which connects canister  24 A and fuel tank  28 , is shortened further. The space in which canister  24 A is installed is larger than that of the prior art. As a result, canister  24 A can be made larger in order for increased adsorption. Because canister  24 A is not placed inside the engine compartment, the engine compartment is simplified. There is no danger of canister  24 A being heated and having a reduced adsorptive performance. In addition, even if an external force acts on the vehicle front side or on the vehicle rear side, there is no danger of canister  24 A being pushed and breaking. This construction has all of these remarkable effects. 
     Referring to FIG. 4, as shown by the dashed line or the alternating long and short dashed line, special constructions of placing canisters  24 B and  24 C on top of or below third cross member  14 - 3  are also possible. 
     Having canisters  24 B and  24 C placed in a region above or below third cross member  14 - 3 , canisters  24 B and  24 C are formed in a flattened shape. Or, when forming the canister, the shape of the surface that contacts third cross member  14 - 3  is formed in a curved surface shape. 
     In this case, similar to the embodiment described above, the pipe length of the vapor pipe, which connects the canister with the fuel tank, is shortened. In addition, when forming a flattened shape canister, it is possible to make the canister large in order to increase the adsorption amount of the canister. The canister is not placed inside the engine compartment, and the inside of the engine compartment is simplified. There is no danger of the canister being heated and having reduced adsorptive performance. Even if an external force acts on the vehicle front or rear side, there is no danger of the canister being pushed and breaking. This construction has all of these remarkable effects. 
     The present invention which has been described in detail above is a canister attachment construction, wherein a canister is attached to a vehicle. The canister is placed between a vapor pipe, which connects to the inside of a fuel tank of the vehicle, and a purge hose, which connects to an intake system of an internal combustion engine. The canister, by way of the vapor pipe, sorbs and retains evaporated fuel generated inside the fuel tank. The sorbed and retained fuel is released by air and supplied to the intake system of the internal combustion engine. A car body frame of the vehicle includes a left and a right side frame, a plurality of cross members placed between the side frames. On one side of the vehicle, there is an exhaust pipe, extending from the vehicle front to the vehicle rear. The canister is installed on a side opposite the exhaust pipe on the vehicle in a region surrounded by a central cross member, which is positioned at an approximately central region of the car body frame, a cross member positioned behind the central cross member, and the side frames. As a result, the pipe length of the vapor pipe, which connects the canister with the fuel tank, is shortened. 
     With this construction, the evaporated fuel, which is generated inside the fuel tank, is more readily sorbed and retained in the canister. In addition, the evaporated fuel is less readily released into the atmosphere during refueling and the like. This is a practical advantage. Furthermore, the space in which the canister is installed is larger than that of the prior art. As a result, the canister can be made larger in order to increase the adsorption amount. An adequate adsorption amount is thereby ensured. The ease of use is improved. Furthermore, because the canister is not placed inside the engine compartment, the inside of the engine compartment is simplified, resulting in minimal danger of the canister being heated and having a reduced adsorptive performance. These are practical advantages. Furthermore, even if an external force acts on the vehicle front or rear, there is no danger of the canister being pushed and breaking. Procedures for preventing the breaking of the canister, in other words procedures for increasing the strength of the canister perimeter members, or procedures for having other reinforcing members, are not necessary. Low costs are maintained, resulting in a significant economic advantages.