JPH06247160A - Fuel vaporization restraining device in fuel tank - Google Patents

Abstract

PURPOSE:To provide a fuel vaporization restraining device in a fuel tank which can restrain fuel from vaporizing, and is excellent in installation. CONSTITUTION:A fuel pump 8 to be housed in the bottom of a subtank 12, and a floating plate 17 are held by the cover 14 of a service hole 13, in this case, the floating plate 17 is inserted in the service hole 13 so as to be assembled therein a state that the plate is slidably held by the cover 14. The floating plate 17 covers the fluid surface of fuel within the subtank 12, and is moved up and down as the fluid surface goes up and down. This constitution thereby causes the contact area of fuel with a space within a fuel tank to be decreased, so that a range within which fuel can vaporize is thereby lessened. Therefore, fuel vaporization speed is lessened, the quantity of vaporized fuel is consequently restricted. Moreover, since the floating plate 17 can easily be installed in the subtank 12 when the cover 14 is installed in the service hole 13, installation can thereby be enhanced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for suppressing vaporized fuel generated in a fuel tank.

[0002]

2. Description of the Related Art Conventionally, an "automobile liquid fuel storage device" disclosed in Japanese Patent Laid-Open No. 64-16426 has been known as a vaporized fuel suppressing device for a main fuel tank.

This device is provided with a float that can move up and down by changing the position of the fuel liquid level in the fuel tank and has a specific gravity lower than that of the fuel, and a bellows that connects the peripheral portion of this float and the inner surface of the tank. As a result, the amount of evaporated fuel generated in the fuel tank is reduced and the change in fuel level due to the movement of the vehicle is reduced.

[0004]

However, the above-mentioned conventional technique has a problem that the float having the bellows connected to the periphery has to be mounted in the fuel tank, resulting in a very bad assembling property.

In view of the above problems, it is an object of the present invention to provide an evaporated fuel generation suppressing device in a fuel tank which can suppress the generation of evaporated fuel and is easy to assemble.

[0006]

In order to achieve the above object, the present invention provides a sub tank formed in a fuel tank,
A fuel pump arranged at the bottom of the sub-tank for delivering the fuel in the fuel tank to a vehicle engine; a hole formed in the upper part of the fuel tank for accommodating the fuel pump in the sub-tank; And a lid that holds the fuel pump and that is slidably held by the lid, covers the liquid surface of the fuel in the sub-tank, and floats following the liquid surface. The technical means of suppressing evaporated fuel generation in the tank is adopted.

[0007]

According to the structure of the evaporated fuel generation suppressing device in the fuel tank of the present invention described above, when the fuel pump is operated, the fuel in the sub-tank is sucked up and delivered to the engine.

Then, covering the liquid surface of the fuel in the sub tank,
Since the float that follows the movement of the liquid level is provided, the contact area between the fuel and the space in the fuel tank is reduced, and the area where the fuel can be vaporized is reduced. Therefore, the fuel evaporation rate is reduced, and as a result, the amount of evaporated fuel generated is suppressed.

Further, since the float is slidably held with respect to the lid of the fuel pump housing hole, the float can be easily attached to the sub tank together with the fuel pump when the lid is attached. Thereby, the assembling property is improved.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an evaporated fuel generation suppressing device in a fuel tank of an internal combustion engine to which the present invention is applied will be described. FIG. 1 is a system configuration diagram of the present embodiment.

As shown in FIG. 1, a multi-cylinder engine 1 of an internal combustion engine is provided with an intake pipe 2 and an exhaust pipe 3 for each cylinder, and an electromagnetic fuel injection valve 4 is provided in the intake pipe 2. Is provided. The plurality of intake pipes 2 are formed so as to gather in the surge tank 35, and a throttle valve 5 for adjusting the amount of intake air is provided in a passage for guiding intake air to the surge tank 35.

On the other hand, the exhaust pipe 3 is provided with an O 2 sensor 6. The O2 sensor 6 outputs a signal corresponding to the oxygen concentration in the exhaust gas. Further, the fuel tank 7 accommodates a fuel pump 8 (not shown in FIG. 1) that delivers fuel to the engine 1. Then, by the fuel pump 8, the fuel in the tank 7 is pressure-fed to each fuel injection valve 4 through the fuel passage 39 and the filter 9. At this time, the pressure regulating valve 1
By 0, the fuel pressure supplied to the injection valve 4 is adjusted to a predetermined pressure. Then, the fuel that has not been injected into the intake pipe 2 by the fuel injection valve 4 is returned to the fuel tank 7 via the pressure regulating valve 10 and the return passage 15.

Further, the discharge passage 36 extending from the upper portion of the fuel tank 7 is communicated with the surge tank 35 via a canister 37 containing activated carbon as an adsorbent. The canister 37 has an atmosphere opening hole 3 for introducing outside air.
8 are provided. In addition, a purge solenoid valve (hereinafter,
A purge valve) 40 is provided. This purge valve 40
Is a spring (not shown), valve body 41, seat portion 4
2, a coil 43, and the like, and a spring (not shown) urges the valve body 41 to abut against the seat portion 42. Further, the valve body 41 separates from the seat portion 42 against the biasing force of the spring by exciting the coil 43. By the excitation of the coil 43, the discharge passage 36 is opened, and the coil 4
The demagnetization of 3 closes the discharge passage 36. The opening of the purge valve 40 is controlled by duty control based on pulse width modulation.

Next, the control circuit 44 composed of a microcomputer, a throttle opening signal from a throttle sensor (not shown) for detecting the opening of the throttle valve 5 and a rotation for detecting the rotational speed of the engine 1. Engine speed signal from a number sensor (not shown), intake pipe internal pressure signal from an intake pipe internal pressure sensor (not shown) that detects the internal pressure of the intake pipe 2, and water temperature sensor that detects the temperature of engine cooling water. A cooling water temperature signal from (not shown) is input. From these signals, the control circuit 44 detects the opening of the throttle valve 5, the engine speed, the intake pipe internal pressure, and the engine cooling water temperature. Further, the control circuit 44 is connected to the purge valve 40 and controls the duty of the purge valve 40.

With the system configuration described above, the fuel injection amount corresponding to the operating state at that time is calculated based on various signals input to the control circuit 44. Then, the operating state of the engine 1 is controlled by injecting the fuel according to the fuel injection amount from the fuel injection valve 4.

Next, the detailed structure of the fuel tank 7 will be described with reference to FIGS. 2 and 3. 2 is a cross-sectional view of the fuel tank 7, and FIG. 3 is a view taken in the direction of arrows I-I in FIG. Inside the fuel tank 7, a sub tank 12 is provided so that the fuel pump 8 can reliably pump the fuel even if the vehicle leans when the remaining amount of fuel is small. An inlet 12 a is formed in the bottom of the sub tank 12 to introduce the fuel in the fuel tank 7 into the sub tank 12. In addition, the sub tank 12
Is fixed to the bottom of the fuel tank 7 by welding or the like so that fuel can be introduced from the inlet 12a.

A fuel pump 8 is provided at the bottom of the sub tank 12. And the discharge pipe 8a of the fuel pump 8
Is connected to a resin hose 11. A circular service hole 13 for accommodating the fuel pump 8 in the sub-tank 12 is formed above the fuel tank 7, and a lid 14 that seals the service hole 13 is provided. The lid 14 is formed so as to penetrate and support the supply pipe 16 and the return passage 15 which communicate with the fuel passage 39 of FIG. 1. The supply pipe 16 is connected to the hose 11 so that the fuel pump 8 is held by the lid 14 via the pipe 18 constituted by the discharge pipe 8a, the hose 11 and the supply pipe 16, and the fuel pump The fuel pressure-fed from 8 can be delivered to the fuel passage 39 via the pipe 18. Further, the return passage 15 is formed so as to project from below the lid 14 into the sub-tank 12 up to the vicinity of the fuel pump 8.
Returned to 2

Further, as shown in FIG. 3, a rectangular floating plate 17 is provided in the sub-tank 12 so as to substantially follow the sectional shape of the sub-tank 12. The floating plate 17 is made of a material having a specific gravity smaller than that of the fuel and capable of expanding and contracting (for example, fluorocarbon rubber, urethane resin having gasoline resistance,
Or a member that has a specific gravity lighter than that of gasoline in which fibers are entangled in a high-molecular polymer with a weak affinity (absorption). As a result, the floating plate 17 is placed in the service hole 1 in this embodiment.
Although it has an area larger than the opening area of No. 3, it can be easily inserted into the sub tank 12 from the hole 13.

Further, the floating plate 17 has holes 17a, 17
b is formed. The hole 17a is formed to have a diameter slightly larger than the outer diameter of the hose 11 so that the pipe 18 can pass through and the floating plate 17 can slide on the pipe 18. On the other hand, the hole 17 b is formed to have a diameter slightly larger than the outer diameter of the return passage 15 so that the return passage 15 can be penetrated and the floating plate 17 can slide with respect to the return passage 15. As a result, the floating plate 17 moves in the vertical direction according to the fuel liquid level in the sub tank 12, and always covers the fuel liquid level in the sub tank 12.

Although the discharge passage 36 of FIG. 1 is opened on the upper surface of the fuel tank 7, this is omitted because it is not related to the present invention. Next, the mounting order of the floating plate 17 of this embodiment will be described.

First, the lid 14 supports the supply pipe 16 and the return passage 15. Then, the hose 1 is connected to the supply pipe 16.
Attach 1. After that, the holes 17 a and 17 b of the floating plate 17 are passed through the hose 11 and the return passage 15. Next, the discharge pipe 8a of the fuel pump 8 is connected. As a result, the floating plate 17 is moved to the conduit 1 by the fuel pump 8.
It is retained without dropping from 8. Therefore, the lid 1
4, the fuel pump 8 and the floating plate 17 are held, and the floating plate 17 is slidable with respect to the lid 14.

By the above, the integrated lid 14, fuel pump 8 and floating plate 17 as shown in the perspective view of FIG.
Is installed from the service hole 13. At this time, since the floating plate 17 can be expanded and contracted as described above, it is deformed and inserted through the service hole 13.

According to the above sequence, the floating plate 17 for covering the fuel liquid level is provided in the sub tank 12. The floating plate 17 reduces the contact area between the fuel and the space inside the fuel tank 7, and reduces the area where the fuel can be vaporized. Therefore, the evaporation rate of fuel is reduced, and as a result, the amount of evaporated fuel generated can be suppressed.

In particular, the sub-tank 12 is likely to generate a large amount of evaporated fuel because the high-temperature fuel is stored by the heat generated by the driving of the fuel pump 8 and the return fuel returned to the sub-tank 12 through the return passage 15. Since the sub-tank 12 is provided with the floating plate 17, it is possible to significantly suppress the generation of evaporated fuel.

Further, since the generation of the evaporated fuel can be suppressed by the above embodiment, the amount of the evaporated fuel passing through the discharge passage 36 can be reduced. Therefore, the canister 37 can be downsized.

Further, as described above, the structure in which the lid 14 holds the fuel pump 8 and the floating plate 17 makes it possible to easily attach the floating plate 17 together with the fuel pump 8 in the sub-tank 12 only by attaching the lid 14. Can be accommodated. Therefore, the assemblability can be improved.

In this embodiment, since the floating plate 17 is held by the fuel pump 8, the lid 14 is prevented from falling off when the fuel tank 7 is attached. However, the present invention is not limited to this, and a holding member (for example, an L-shaped member) that allows the floating plate 17 to follow the liquid surface of the fuel and that does not fall off when the lid 14 is attached to the fuel tank 7. , May be attached to the lid 14.

Further, in this embodiment, the floating plate 19 for covering the liquid surface of the fuel stored in the space between the outer circumference of the sub tank 12 and the inner circumference of the fuel tank 7 is attached in advance when the fuel tank 7 is assembled. The floating plate 19 is made of the same material as the floating plate 17. And by the floating plate 19,
The amount of evaporated fuel can be suppressed. Further, the floating plate 19 can suppress the amount of evaporated fuel generated when the fuel is supplied from the fuel supply port 20. The floating plate 19 may be inserted from the service hole 13 after the fuel tank 7 is assembled. At this time, the floating plate 19
By utilizing the flexibility of the material of the fuel tank, the floating plate 19 is moved from the gap between the upper end of the sub tank 12 and the inner wall surface of the fuel tank 7 to the space between the outer circumference of the sub tank 12 and the inner circumference of the fuel tank 7, Float on the liquid surface.

Even if the floating plate 19 is not provided, the floating plate 1 is provided with the liquid level of the sub tank 12 where the fuel becomes high temperature.
Covering with 7 can sufficiently suppress the amount of evaporated fuel. In the above embodiment, the floating plate 17 is
The sub-tank 12 covers almost the entire liquid surface of the fuel, but if 70 to 80% of the liquid surface area is covered, the generation of evaporated fuel can be sufficiently suppressed.

[0030]

As described above, according to the structure and operation of the fuel vapor generation suppressing device for a fuel tank of the present invention, the float that is slidably held by the lid that closes the fuel pump housing hole is provided in the sub tank. Since the fuel liquid level is covered with and follows this liquid level, the amount of evaporated fuel can be suppressed. In particular, because a float is provided in the sub-tank where a large amount of evaporated fuel is likely to be generated by the heat generated by the fuel pump and the return fuel,
Evaporative fuel generation can be greatly suppressed.

Further, since the float is held slidably with respect to the lid, the lid can be easily attached to the fuel tank. Therefore, the assemblability can be improved.

[Brief description of drawings]

FIG. 1 is a system configuration diagram of the present embodiment.

FIG. 2 is a cross-sectional view of a fuel tank of this embodiment.

FIG. 3 is a view taken along the line I-I of FIG.

FIG. 4 is a perspective view of a main part of this embodiment.

[Explanation of symbols]

 7 Fuel Tank 8 Fuel Pump 12 Sub Tank 13 Service Hall 14 Lid 17 Floating Plate

Claims (1)

[Claims] 1. A sub-tank formed in a fuel tank, a fuel pump arranged at the bottom of the sub-tank for delivering the fuel in the fuel tank to a vehicle engine, and a fuel pump formed at the top of the fuel tank. A hole for accommodating the pump in the sub-tank, a lid for closing the hole and holding the fuel pump, a slidably held by the lid and covering a fuel liquid level in the sub-tank, and this liquid A device for suppressing the generation of evaporated fuel in a fuel tank, comprising: a float that follows a surface.