JP4767697B2 - Fuel tank - Google Patents

Description

  The present invention includes a tank body that stores fuel, a pump module that is disposed in the tank body and pumps the fuel, and a sub-tank that liquefies evaporated fuel generated in the tank body and returns the fuel to the tank body. It relates to a fuel tank.

  According to Japanese Patent Application No. 2005-376027, the applicant liquefies the evaporated fuel in the sub tank when the temperature of the main tank rises, and conversely liquefies the evaporated fuel in the main tank when the temperature of the main tank decreases. By reducing the fuel vapor pressure in the sub-tank, when the temperature of the main tank next rises, liquefaction of evaporated fuel in the sub-tank is promoted, and evaporative fuel is generated regardless of the temperature state of the tank body and sub-tank. An evaporative fuel processing device capable of effectively suppressing the above is proposed.

  In the above Japanese Patent Application No. 2005-376027, the temperature of the tank body is set higher than the temperature of the sub tank when the temperature of the fuel tank is increased, and the temperature of the sub tank is set higher than the temperature of the tank body when the temperature of the fuel tank is decreased. An embodiment in which the sub tank is disposed inside the tank body is disclosed. However, since an in-tank type reservoir unit is disposed inside the tank body, there is a problem that if the sub tank is disposed inside the tank body in addition to the reservoir unit, the assembly thereof becomes troublesome.

  The present invention has been made in view of the above-described circumstances, and an object of the present invention is to allow a pump module and a sub tank to be easily assembled inside a tank body.

In order to achieve the above object, according to the first aspect of the present invention, a tank main body for storing fuel, a pump module arranged in the tank main body for pumping fuel, and evaporation generated in the tank main body. A fuel tank in which the fuel is liquefied and returned into the tank body, and the subtank is integrated with the pump module and disposed in the tank body. The interior of the subtank is divided into a liquid phase part and a gas phase part. The gas phase part of the tank body and the liquid phase part of the sub tank are connected by a first communication path, and the gas phase part of the sub tank and the liquid phase part of the tank body are connected by a second communication path. Part of the pumped fuel is supplied to the sub tank via the fuel supply passage, and the second communication passage and the fuel supply passage are housed inside the tank body, and the pump module. The reservoir unit includes a reservoir unit, and an upper surface of the tank body is formed with an opening having a dimension that allows the reservoir unit and the sub tank to pass through alone but not at the same time. And the sub tank is fixed to the lower surface of the flange at a position offset in the horizontal direction with respect to the reservoir unit, and the expansion / contraction coupling mechanism is slidable in the vertical direction with respect to the reservoir unit. And a second sliding member fixed to the lower surface of the flange and slidable in the vertical direction with respect to the first sliding member. .

  According to the configuration of the first aspect, the sub-tank that liquefies the evaporated fuel generated in the tank main body and returns it to the tank main body and the pump module that pumps the fuel in the tank main body are integrated in the tank main body. As a result, the assembly of the pump module and the sub tank can be completed at a time, thereby reducing the number of assembly steps. Furthermore, not only is the means for fixing the sub tank separately from the pump module unnecessary, but also the piping work for connecting the sub tank to the tank main body when the tank main body is mounted on the vehicle body becomes unnecessary, and the pipe penetrates the pipe. Thus, the evaporated fuel can be prevented from being released into the atmosphere. Further, the number of openings provided in the tank body can be reduced from two to one, and the amount of fuel vapor permeated from the flange that closes the openings can be reduced.

Also, a second communication passage that connects the gas phase portion of the sub tank and the liquid phase portion of the tank main body, and a fuel supply passage that replenishes the sub tank with a part of the fuel pumped from the pump module are housed inside the tank main body. Therefore, it is not necessary to dispose the second communication passage and the fuel supply passage outside the tank body, and not only the connection work of the second communication passage and the fuel supply passage becomes unnecessary when the tank body is mounted on the vehicle body. It is possible to prevent the evaporated fuel from being diffused into the atmosphere through the two communication passages and the fuel supply passage.

Also, the reservoir unit of the pump module is inserted from the opening of the tank body, moved laterally inside the tank body, and then the sub-tank is inserted from the opening of the tank body while contracting the telescopic coupling mechanism, and then the tank body with the flange By closing the opening, the reservoir unit and the sub-tank can be accommodated inside the tank body while minimizing the size of the opening, whereby the evaporated fuel from around the flange closing the opening can be stored. Leakage can be minimized. At this time, an expansion / contraction coupling mechanism that connects the flange and the reservoir unit is fixed to the lower surface of the flange with respect to the first sliding member that is slidable in the vertical direction with respect to the reservoir unit. Since the vertical sliding dimension of the tank body is small and the vertical dimension of the sub-tank is large, the expansion / contraction coupling mechanism is sufficiently moved from the expanded state to the contracted state. The sub-tank can be inserted into the tank body without hindrance.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below based on examples of the present invention shown in the accompanying drawings.

  1 to 7 show an embodiment of the present invention, FIG. 1 is a view showing a state where a pump module is mounted on a tank body, FIG. 2 is a view taken along line 2-2 in FIG. 1, and FIG. 2 is a cross-sectional view taken along line 3-3 in FIG. 2, FIG. 4 is a view showing a state in which the telescopic connection mechanism is extended, FIG. 5 is a schematic view showing the structure of the tank main body and the sub tank, and FIG. FIG. 7 is an explanatory view of the operation when the pump module is assembled.

  As shown in FIGS. 1 to 4, an in-tank pump module 12 that supplies fuel to the engine is housed inside a tank body 11 of a fuel tank made of synthetic resin for automobiles. The tank body 11 has a flat shape in which the distance between the upper wall 11a and the lower wall 11b is close, and the pump module 12 includes a flange 13 that is detachably fixed to an opening 11c formed in the upper wall 11a of the tank body 11. The flange 13 is fixed by a cap 14 that is screwed into the opening 11 c of the tank body 11. A reservoir unit 16 is supported on the lower surface of the flange 13 via a telescopic coupling mechanism 15 that can expand and contract.

  The reservoir unit 16 is a container-shaped reservoir 17 having an open upper surface, a motor-integrated fuel pump 18 housed in the reservoir 17, and an arc shape disposed so as to surround a part of the outer periphery of the fuel pump 18. And a strainer case 19. The fuel pump 18 supplies the fuel sucked up through the pump filter 20 to the upper end of the strainer case 19 through the communication passage 21, and the fuel purified by passing through the strainer element 22 housed in the strainer case 19 is a pressure regulator. 23, the fuel duct 24 and the joint 25 of the flange 13 are supplied to the engine. A sub-tank 26 for liquefying the evaporated fuel generated inside the tank body 11 is integrally formed on the lower surface of the flange 13. A liquid level sensor 28 that is operated by a float 27 is provided on a side surface of the reservoir 17.

  The reservoir unit 16 and the sub tank 26 are offset so as not to overlap in plan view. The outer diameter of the reservoir unit 16 is set slightly smaller than the inner diameter of the opening 11c of the tank body 11, and the maximum diameter of the sub tank 26 is also set smaller than the inner diameter of the opening 11c of the tank body 11 (see FIG. 2). The height of the reservoir unit 16 and the sub tank 26 is small with respect to the distance between the upper wall 11a and the lower wall 11b of the tank body 11, but the sum of the height of the reservoir unit 16 and the height of the sub tank 26 is large ( (See FIG. 1).

  The telescopic connection mechanism 15 includes a pipe-shaped first sliding member 29 slidably fitted in a support hole 17 a formed in the upper portion of the reservoir 17, and a rod-shaped second sliding member whose upper end is fixed to the lower surface of the flange 13. The first sliding member 29 and the second sliding member 30 are telescopically fitted and slidable with each other. A circlip 31 is attached to the lower end of the second sliding member 30 so as not to fall off the first sliding member 29. A coil spring 32 is mounted on the outer periphery of the first sliding member 29, and the first sliding member 29 is biased in a direction protruding upward from the reservoir 17 by the elastic force of the coil spring 32. The stretchable distance of the telescopic connection mechanism 15 is set to be larger than the height of the sub tank 26.

  FIG. 5 is a schematic diagram showing the structure of the tank body 11 and the sub-tank 26. The inside of the tank body 11 is divided into a liquid phase portion 41 filled with fuel and a gas phase portion 42 filled with evaporated fuel. When the fuel level 43 changes due to fuel supply or fuel consumption, the volume of the liquid phase portion 41 and the volume of the gas phase portion 42 change. The sub-tank 26 is divided into a liquid phase portion 44 filled with fuel and a gas phase portion 45 filled with evaporated fuel, and the fuel liquid level 46 is basically constant. The gas phase part 42 of the tank body 11 and the liquid phase part 44 of the sub tank 26 are connected by the first communication path P1, and the gas phase part 45 of the sub tank 26 and the liquid phase part 41 of the tank body 11 are connected by the second communication path P2. Connected by.

  The canister C capable of adsorbing evaporated fuel includes a charge port 47, a purge port 48, and a drain port 49. The charge port 47 is connected to the gas phase portion 45 of the sub tank 26 by a charge passage 50, and the purge port 48 is purged. It is connected to the intake passage (not shown) of the engine via the passage 51, and the drain port 49 is released to the atmosphere.

  A fuel supply passage 52 that branches through a pressure regulator 23 that regulates the fuel discharged from the fuel pump 18 is connected to the sub tank 26. The height at which the fuel supply passage 52 opens to the sub tank 26 is set equal to the height at which the second communication passage P2 opens to the sub tank 26, and the height is the height of the fuel level 46 of the sub tank 26. An orifice 35 is formed in the fuel supply passage 52, and most of the fuel that has passed through the pressure regulator 23 is returned to the tank body 11, but part of the fuel passes through the orifice 35 and is supplied to the sub tank 26. The height at which the fuel supply passage 52 opens into the sub tank 26 may be set higher than the height at which the second communication passage P2 opens into the sub tank 26.

  The vicinity of the filler port 53 at the upper end of the filler tube 53 extending upward from the tank body 11 is connected to the gas phase portion 42 of the tank body 11 via the evaporated fuel return passage 55. The vaporized fuel return passage 55 returns the vaporized fuel in the gas phase portion 42 of the tank body 11 to the vicinity of the fuel filler port 54 and ejects it from the fuel gun when fuel is supplied from the fuel filler port 54 to the filler tube 53 with the fuel gun. By returning to the tank body 11 together with the fuel to be discharged, it has a function of preventing outside air from being sucked into the tank body 11.

  In the present embodiment, the first communication path P1 is not directly connected to the gas phase portion 42 of the tank body 11, but is indirectly connected via the evaporated fuel return path 55. 1 and 2, the joints 33 and 34 extending from the sub tank 26 through the flange 13 and extending upward are connected to the charge passage 50 and the first communication passage P1, respectively.

  Next, the operation of the embodiment of the present invention having the above configuration will be described.

  Although the temperature of the fuel tank also rises as the outside air temperature rises during the daytime, the temperature of the tank body 11 becomes higher than the temperature of the sub tank 26, so that air and vaporized fuel that can exist in the gas phase portion 42 of the tank body 11. The number of moles of the air-fuel mixture decreases, and at the same time, evaporated fuel is generated from the liquid phase portion 41 to the gas phase portion 42 of the tank body 11 as the fuel vapor pressure increases. As a result, the air / vapor fuel mixture in the gas phase portion 42 of the tank body 11 is discharged as bubbles to the liquid phase portion 44 of the sub tank 26 via the first communication path P1 (see arrow a). Since the partial pressure of the evaporated fuel supplied from the tank main body 11 is higher than the partial pressure of the evaporated fuel existing in the sub tank 26, the difference is liquefied and dissolved in the liquid phase portion 44 of the sub tank 26. Thereby, the ratio of the evaporated fuel charged in the canister C through the charge passage 50 out of the evaporated fuel generated in the gas phase portion 42 of the tank body 11 can be reduced, and the canister C can be downsized.

  Although the temperature of the fuel tank also decreases as the outside air temperature decreases at night, the temperature of the tank body 11 is lower than the temperature of the sub-tank 26, so the mole of the mixture that can exist in the gas phase portion 42 of the tank body 11. As the fuel vapor pressure decreases, the vaporized fuel liquefies from the gas phase portion 42 to the liquid phase portion 41 of the tank body 11. As a result, the air-fuel mixture in the gas phase portion 45 of the sub tank 26 is introduced into the liquid phase portion 41 of the tank body 11 via the second communication path P2.

  As described above, when the evaporated fuel in the gas phase portion 45 of the sub tank 26 is sucked by the negative pressure generated in the gas phase portion 42 of the tank body 11, the outside air sucked from the drain port 49 of the canister C causes the canister C to enter the canister C. The vaporized fuel that has been charged is purged, and the purged vaporized fuel flows into the gas phase portion 45 of the sub-tank 26 through the charge passage 50 and is returned to the liquid phase portion 41 of the tank body 11 to be liquefied. So-called back purge is possible. By performing the back purge while the engine is stopped, the amount (weight) of the evaporated fuel charged in the canister C can be kept low, thereby evaporating from the canister C to the engine intake passage when the engine is operating. When purging the fuel, the amount of evaporated fuel in the purge air can be reduced to minimize the influence on the accuracy of engine air-fuel ratio control.

  Since the air-fuel mixture supplied from the canister C to the gas phase portion 45 of the sub tank 26 by the back purge has a relatively low concentration of evaporated fuel, the liquid phase portion 44 according to the fuel vapor pressure of the gas phase portion 45 of the sub tank 26. Generation of evaporated fuel from the fuel is promoted, and a phenomenon in which the fuel component changes (so-called withering) occurs, and the fuel vapor pressure in the gas phase portion 45 of the sub tank 26 decreases. When the fuel vapor pressure in the gas phase portion 45 of the sub-tank 26 decreases in this manner, the liquefaction of the evaporated fuel supplied from the tank body 11 to the sub-tank 26 is more effectively promoted when the temperature of the tank body 11 rises. can do.

  The back purge occurs even in a conventional fuel tank that does not have a sub tank. In this case, the relatively low concentration evaporated fuel purged from the canister is supplied to the fuel tank. The amount of evaporated fuel dissolved in the water becomes relatively small. On the other hand, in this embodiment, the evaporated fuel purged from the canister C is supplied to the tank body 11 through the sub-tank 26 in an increased concentration, so that it is dissolved and recovered in the liquid phase portion 41 of the tank body 11. The amount of evaporated fuel is relatively large.

  When the fuel level 46 of the sub tank 26 becomes lower than the opening end of the first communication path P1, the evaporated fuel supplied from the tank body 11 via the first communication path P1 can be directly introduced into the liquid phase portion 44 of the sub tank 26. In addition, the fuel in the liquid phase portion 44 is not returned to the tank body 11 via the second communication path P2, and the fuel may become old and change its components. Fresh fuel is supplied to the sub tank 26 via the supply passage 52. When the fuel level 46 of the sub tank 26 becomes higher than the opening at the upper end of the second communication path P2 due to the fuel supplied from the fuel supply path 52, the excess fuel is returned to the tank body 11 via the second communication path P2. As a result, the fuel level 46 of the sub tank 26 is always maintained at a constant height.

  As described above, when the temperature of the tank body 11 rises, the evaporated fuel is liquefied in the sub-tank 26, and conversely, when the temperature of the tank body 11 falls, the evaporated fuel is liquefied in the tank body 11 and By lowering the fuel vapor pressure, when the temperature of the tank body 11 is increased next time, liquefaction of the evaporated fuel in the sub-tank 26 is promoted, and the temperature state of the tank body 11 and the sub-tank 26 is whatever the temperature state of the evaporated fuel. Generation | occurrence | production can be suppressed effectively. As a result, even if the capacity of the canister C is reduced, it is possible not only to prevent the evaporated fuel from being released into the atmosphere, but also to reduce the evaporated fuel purged from the canister C to the engine intake system. The accuracy of air-fuel ratio control can be increased.

  Next, assembly of the pump module 12 to the tank body 11 will be described.

  As shown in FIG. 6, with the cap 14 removed from the tank body 11 and the opening 11c exposed, the reservoir unit 16 of the pump module 12 is inserted into the tank body 11 through the opening 11c. At this time, the first and second sliding members 29 and 30 of the telescopic connection mechanism 15 are in the most extended state, and the lower end of the sub tank 26 provided on the lower surface of the flange 13 is located higher than the upper surface of the opening 11c.

  Subsequently, as shown in FIG. 7, the reservoir unit 16 is slid laterally inside the tank body 11, and the flange 13 is positioned immediately above the opening 11c. From this state, when the flange 13 is lowered while the second sliding member 30 of the telescopic coupling mechanism 15 is fitted inside the first sliding member 29, the lower half of the sub tank 26 passes through the opening 11c and the tank body 11 Inserted inside. When the flange 13 is further lowered after the second sliding member 30 of the telescopic coupling mechanism 15 is completely fitted into the first sliding member 29, the first sliding member 29 compresses the coil spring 32 while compressing the coil spring 32. 17, the sub tank 26 is finally housed in the tank body 11 and the flange 13 is fitted into the opening 11 c. Therefore, as shown in FIG. 1, the pump module 12 including the reservoir unit 16 and the sub tank 26 can be assembled inside the tank body 11 by screwing the cap 14 into the opening 11c.

  In the state where the pump module 12 is assembled in this way, the elastic force of the coil spring 32 acts to urge the reservoir unit 16 downward against the flange 13, so that the internal pressure of the tank body 11 changes. Even if the distance between the upper wall 11a and the lower wall 11b increases or decreases, the lower surface of the reservoir unit 16 can be pressed against the lower wall 11b of the tank body 11 to prevent the play.

  Accordingly, the telescopic coupling mechanism 15 that connects the flange 13 and the reservoir unit 16 has a structure in which the first and second sliding members 29 and 30 are connected in two stages. A sufficient amount of relative movement can be secured. As a result, even when the vertical dimension of the sub tank 26 is large, when the reservoir unit 16 is slid horizontally within the tank body 11 (see FIG. 7), the lower end of the sub tank 26 interferes with the opening 11c of the tank body 11. Thus, the pump module 12 can be assembled without hindrance. When the assembly is completed, the reservoir unit 16 and the sub tank 26 are juxtaposed in the left-right direction instead of the up-down direction, so that the assembly to the tank body 11 having a small vertical dimension is possible. Moreover, since the first and second sliding members 29 and 30 are telescopically fitted, the reservoir unit 16 can be guided in the vertical direction with respect to the flange 13 with a simple structure.

  Further, since the sub tank 26 is integrated with the reservoir unit 16 without being arranged outside the tank main body 11 and arranged inside the tank main body 11, means such as a mounting bracket for fixing the sub tank 26 outside the tank main body 11. Is no longer necessary. Moreover, the tank body includes a second communication path P2 that communicates the gas phase portion 45 of the sub tank 26 and the liquid phase portion 41 of the tank body 11, and a fuel supply path 52 that communicates the pressure regulator 23 and the gas phase portion 45 of the sub tank 26. 11 is not necessary to connect the second communication passage P2 and the fuel supply passage 52 when the tank body 11 is mounted on the vehicle body, and the second communication passage P2 and the fuel supply passage 52 are not required. It is possible to prevent the evaporated fuel from being diffused to the atmosphere through 52. In particular, since the reservoir unit 16 and the sub tank 26 are integrated to form the pump module 12, the assembly of the reservoir unit 16 and the sub tank 26 can be completed simply by assembling the pump module 12 to the tank body 11, and the number of assembling steps can be reduced. Is possible.

  The size of the opening 11c of the tank main body 11 may be a size that allows the reservoir unit 16 and the sub tank 26 to pass through each independently, and needs to be a size that allows the reservoir unit 16 and the sub tank 26 to pass through simultaneously. Therefore, the size of the opening 11c can be suppressed to a necessary minimum size. As a result, the permeation amount of the evaporated fuel from the periphery of the flange 13 that closes the opening 11c can be reduced, and the leakage of the evaporated fuel from the entire fuel tank can be minimized.

  Although the embodiments of the present invention have been described above, various design changes can be made without departing from the scope of the present invention.

  For example, the first and second sliding members 29 and 30 are not limited to those that fit telescopically, and may be any structure that can slide relative to each other.

Further, the structure of the sub tank 26 is not limited to the embodiment, and any structure that can liquefy evaporated fuel may be used .

The figure which shows the state where the pump module was installed in the tank body 2-2 line view of FIG. 3-3 sectional view of FIG. The figure which shows the state which extended the telescopic connection mechanism Schematic diagram showing the structure of the tank body and sub tank Action diagram when assembling the pump module Action diagram when assembling the pump module

11 Tank body 11a Upper wall 11c Opening 12 Pump module 13 Flange 15 Telescopic coupling mechanism 16 Reservoir unit 26 Sub tank 29 First sliding member 30 Second sliding member
41 liquid phase part
42 gas phase part
44 liquid phase parts
45 gas phase part
52 Refueling passage
P1 first communication passage
P2 second communication passage

Claims (1)

A tank main body (11) for storing fuel, a pump module (12) disposed in the tank main body (11) and pumping fuel, and the evaporated fuel generated in the tank main body (11) is liquefied to liquefy the tank main body (11) A fuel tank comprising a sub-tank (26) returning to the inside, wherein the sub-tank (26) is integrated with the pump module (12) and disposed in the tank body (11) ,
The interior of the sub tank (26) is divided into a liquid phase part (44) and a gas phase part (45). The gas phase part (42) of the tank body (11) and the liquid phase part (44) of the sub tank (26). Are connected by the first communication path (P1), the gas phase part (45) of the sub tank (26) and the liquid phase part (41) of the tank body (11) are connected by the second communication path (P2), Part of the fuel pumped from the pump module (12) is supplied to the sub tank (26) through the fuel supply passage (52), and the second communication passage (P2) and the fuel supply passage (52) serve as the tank body (11). ) Is housed inside
The pump module (12) includes a reservoir unit (16);
On the upper wall (11a) of the tank main body (11), an opening (11c) having a dimension that allows the reservoir unit (16) and the sub tank (26) to pass alone but cannot pass through at the same time is formed. The lower surface of the flange (13) that closes the opening (11c) and the reservoir unit (16) are connected via the telescopic connection mechanism (15), and at a position that is offset horizontally with respect to the reservoir unit (16). The sub tank (26) is fixed to the lower surface of the flange (13),
The telescopic coupling mechanism (15) is fixed to the lower surface of the first sliding member (29) slidable in the vertical direction with respect to the reservoir unit (16) and the flange (13). A fuel tank comprising: a second sliding member (30) slidable in a vertical direction with respect to (29) .

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