JPH051645Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a fuel vapor emission prevention device during fuel refueling.

[Conventional technology]

An inlet pipe extending upward is attached to the fuel tank of an automobile for refueling. A breather pipe is connected from the upper wall of the fuel tank to near the upper end of this inlet pipe, so that when refueling, the pressure inside the tank can be released and the tank can be filled with fuel. In such a configuration, fuel vapor generated during refueling is discharged into the atmosphere through the open inlet pipe.

Therefore, it has been devised to connect a breather pipe to a coal canister to prevent fuel vapor from being discharged into the atmosphere. There is.

[Problem that the invention attempts to solve]

JP-A-61-191427 and JP-A-61-
In the fuel vapor emission prevention device described in Publication No. 132763, a solenoid valve is placed in the middle of a breather pipe that connects the fuel tank and the charcoal canister. I only open it. By the way, when the fuel tank is connected to the carbon dioxide canister through a breather pipe, there is a problem that fuel flows into the carbon canister through the breather pipe during refueling, and the liquid level in the inlet tube of the fuel tank does not rise. In order to solve this problem, as shown in the above publication, it is necessary to raise the breather pipe to a position higher than the fuel filler port at the upper end of the inlet tube. As a result, during refueling, the fuel rises into the rising portion of the breather pipe and the inlet tube, and the refueling nozzle senses that the inlet tube is full and then stops. Further, when the fuel tank is filled, a certain amount of air holding space is required above the liquid level of the fuel. if,
If the air (fuel vapor) holding volume above the fuel surface is extremely small, the pressure inside the tank will rise significantly due to the inverse relationship between pressure and volume, making it necessary to make the fuel tank plate thicker. Become. For this reason, it is necessary to regulate the fuel level when the tank is filled to a predetermined level to ensure an air holding volume between the upper wall of the fuel tank and the fuel level. The above-mentioned Japanese Patent Application Laid-open No. 132763/1983 attempts to solve these requirements, but this requires the breather pipe to rise to a higher position than the oil filler port at the upper end of the inlet tube. It is. It is not preferable to extend the breather pipe high above the fuel tank. Particularly in automobiles where the fuel tank is located under the seat, it is often difficult to extend the breather pipe high above the fuel tank. Further, with this configuration, there is a problem in that liquid fuel enters the breather pipe during refueling, and when the liquid fuel comes into contact with the carbon dioxide canister, the performance of the carbon canister deteriorates.

[Means for solving problems]

In order to solve the above problems, a fuel vapor discharge prevention device according to the present invention connects a fuel tank, a fuel vapor adsorption means, and the fuel vapor adsorption means, and reduces the pressure inside the tank when refueling. an escaping conduit, a solenoid valve disposed in the middle of the conduit in the fuel tank and opened during fuel refueling, and a float provided in the fuel tank that closes the inner opening of the conduit to regulate the liquid level of the fuel. The solenoid valve and the float are arranged in a fuel tank as an integral structure, and a liquid return wall is provided in the passage between the float and the solenoid valve in the conduit. It is something to do.

〔Example〕

Hereinafter, the present invention will be explained based on the drawings.

In FIG. 3, a fuel tank 10 has an inlet pipe 12 for supplying fuel, and a cap 14 is screwed onto the inlet end of the inlet pipe 12. fuel tank 10
A fuel pipe 16 for supplying fuel to an engine (not shown) and a return pipe 18 for returning excess fuel are inserted into the holder.

In FIG. 3, two activated carbon canisters 20, 22 are provided. This can also be a common charcoal canister. Charcoal canisters 20 and 22 are each filled with activated carbon. One of the charcoal canisters 20 is connected to the upper space of the fuel tank 10 by an evaporative pipe 24 like the conventional one. A check valve 26 is disposed in the middle of the evaporative pipe 24 or at the inlet of the carbon canister 20. The check valve 26 is bidirectional and allows fuel vapor to flow from the fuel tank 10 toward the coal canister 20 when the pressure of the fuel vapor in the fuel tank 10 increases due to thermal expansion or the like, thereby controlling the fuel level. This allows air to flow from the charcoal canister 20 toward the fuel tank 10 when the pressure inside the fuel tank 10 becomes lower than atmospheric pressure due to a drop in pressure or the like. Therefore, when the cap 14 is closed and the pressure inside the fuel tank 10 is high, fuel vapor flows into the coal canister 2.
It is adsorbed to 0. The charcoal canister 20 has a fuel vapor inlet 28 and an outlet 30 as in the conventional one.
and an air inlet 32, with an outlet 30 connected by a pipe 34 to a position downstream of a throttle valve 38 in an intake passage 36 of the engine. pipe 34
There is a solenoid valve 40 in the middle, which is opened according to engine operating conditions by a control unit (ECU) 42 using a microprocessor. When the electromagnetic valve 40 is opened, the fuel vapor adsorbed in the charcoal canister 20 is sucked into the intake passage 36 by the manifold negative pressure. burned in the engine.

The second carbon canister 22 is connected to the upper space of the fuel tank 10 by a breather pipe 44 . The second charcoal canister 22 similarly has a fuel vapor inlet 46 , an outlet 48 , and an air inlet 50 , with the outlet 48 being similar to the first charcoal canister 20 by a pipe 52 merging with the pipe 34 . is connected to the intake passage 36.

The fuel tank 10 is generally flat, as shown in FIG. 3, and is suitable for placement under a seat or the like. The upper wall of the fuel tank 10 is formed of three parts 10a, 10b, and 10c, with the central part 10a having parts 10b and 10c on both sides.
It is higher than 10c. Evapo pipe 24
And a breather pipe 44 is connected to this raised central upper wall portion 10a.

A normally closed electromagnetic valve 54 is disposed in the middle of the breather pipe 44, and a float 56 is provided in the fuel tank 10 to close the inner opening of the breather pipe 44 and regulate the fuel level. Although shown on the outside in FIG. 3, as shown in detail in FIG. 1, the solenoid valve 54 and the float 56 are integrally constructed and arranged inside the fuel tank 10. As shown in FIGS. 1 and 3, the base 60 of the valve gear housing 58 is secured to the central upper wall portion of the fuel tank 10 by screws 62.
0a facing inward. The base 60 is attached to the upper wall portion 10a via a gasket 64, and supports the solenoid valve 54 and float 56 side by side within a valve device housing 58 extending downward from the base 60. The end of the breather pipe 44 is attached to the base 60 so as to stand upright, and the end cut is horizontal, so that the solenoid valve 5
It forms a valve seat 66 for 4. Solenoid valve 54
has a valve member 68 coaxially aligned with the upright end of breather pipe 44 and engageable with valve seat 66 .

The base 60 and valve gear housing 58 are made of plastic and have a breather pipe 4 therein.
A breather passage 70 is formed that continuously communicates with the air conditioner 4 . At the terminal end of the breather passage 70 of the valve housing 58, a float cage 72 for the float 56 is mounted parallel to the solenoid valve 54 at a position offset from the solenoid valve 54. The float cage 72 is provided with an appropriate hole 72a, which allows the fuel tank 1 to be inserted into the float cage 72.
Fuel at the same level as 0 can enter. A valve seat 74 is provided at the upper end of the float cage 72, and when the liquid level of the fuel in the fuel tank 10 becomes high, the float 56 floats, and when the liquid level of the fuel in the fuel tank 10 becomes sufficiently full, the float 56 opens the valve. Seat 74 can be engaged to close breather passage 70.

As shown in FIGS. 1 and 2, the breather passage 70 includes a horizontal chamber-shaped passage 70a formed to surround the open end of the breather pipe 44 and the valve member 68, and a horizontal chamber-shaped passage 70a formed to surround the open end of the breather pipe 44 and the valve member 68. It is formed by a vertical hole 70b that connects the passage 70a and the valve seat 74. The horizontal chamber-shaped passage 70a is formed by opposing horizontal upper and lower surfaces 70c and 70d and an annular housing side wall 58a. Furthermore, a liquid return wall 76 is provided that extends upward from the lower surface 70d of the horizontal chamber-like passage 70a, and as shown in FIG. connected,
Its height is such that it does not reach the upper surface 70c. Further, a second liquid return wall 78 is provided to surround this liquid return wall 76, and this second liquid return wall 78 extends downward from the upper surface 70c. The height of the first liquid return wall 76 is higher than the lower end of the second liquid return wall 78. Therefore, when the fuel vapor and the liquid fuel in the form of spray or droplets rise up the hole 70b, they reach the upper surface 70c and the first
Only those who can overcome the liquid return wall 76 can proceed further. At this stage, most of the heavy droplet fuel will fall again through the hole 70b.
The fuel vapor and liquid fuel in the form of spray or droplets that have climbed over the first liquid return wall 76 are transferred to the second liquid return wall 78.
The liquid fuel takes an inverted U-shaped course from the hole 70b, and at this time, the upward movement of the heavy droplet-like fuel is eliminated, and as a result, the liquid fuel is prevented from entering the breather pipe 44 extending upward from there. .
Therefore, the breather pipe 44 can be bent horizontally immediately after rising vertically. Further, a pore 8 opened between the first liquid return wall 76 and the second liquid return wall 78 of the horizontal chamber-like passage 70a.
0 is provided so that the fuel accumulated in the chamber-like passage 70a can be returned to the vertical hole 70b. This pore 80 is not only narrow like a constriction but also includes a curved portion, so that liquid fuel cannot rise therein.

Returning to FIG. 1, by having the solenoid valve 54 directly engage a valve seat 66 formed at the end of the breather pipe 44, the solenoid valve 54 can be moved inside the fuel tank 10 in a smaller space. This allows the solenoid valve 54 to be placed outside the fuel tank 10, thereby solving the space constraints that would otherwise arise when the solenoid valve 54 is mounted outside the fuel tank 10. The solenoid valve 54 has a solenoid coil 8 wound on a bobbin 82 around a valve member 68.
4, a fixed piece 86 disposed opposite to the rear side of the valve member 68, and a spring 88 disposed between the valve member 68 and the fixed piece 86, and for energizing the solenoid coil 84. Therefore, the valve member 68 is attracted by the fixed piece 86 and opens the valve seat 66. When the solenoid coil 84 is not energized, the valve member 68 is biased by the spring 88 and engages with the valve seat 66 . The solenoid valve 54 further includes a magnetic body for forming a magnetic circuit.

Referring to FIG. 3, a solenoid valve 54 disposed in a breather pipe 44 is connected to a battery 92 via a relay 90. Relay 90 receives a signal from refueling detection means 94 that detects whether fuel is being refilled. The refueling detection means 94 is obtained by providing a switch in conjunction with the inlet pipe cap 14. Additionally, a switch may be provided in conjunction with a fuel lid opener in the driver's seat of the vehicle. If refueling is in progress, the switch of the relay 90 is closed, the solenoid valve 54 is energized, and the solenoid valve 54 is opened. At this time, since the liquid level of the fuel in the fuel tank 10 is low, the float 56 is also away from its valve seat 74, so that the fuel vapor generated during refueling is transferred from the breather pipe 44 to the second carbon canister 22. The fuel vapor is adsorbed onto activated carbon. Then, during refueling, the almost liquid fuel that becomes splashes or splashes and jumps up, does not enter the breather pipe 44, and falls again. As refueling progresses, the liquid level in the fuel tank 10 rises, and when the tank is almost full, the float 56 closes its valve seat 74, preventing fuel from entering the breather passage 70, thus regulating the fuel level. As refueling progresses, a refueling nozzle (not shown) senses that it is full and stops. When the refueling is completed, the signal from the refueling detection means 94 changes, the switch of the relay 90 is opened, and the solenoid valve 54 is also closed.

[Effect of idea]

As explained above, according to the present invention, the fuel vapor generated during refueling can be adsorbed by the adsorption means without being discharged into the atmosphere, and by providing a float that regulates the liquid level, the liquid fuel can be adsorbed. It is possible to prevent the fuel from reaching the fuel tank and to fill the fuel up to the specified value. The action of the float, the valve device, and the liquid return wall provided between them prevents liquid fuel from reaching the adsorption means through the breather pipe, and only fuel vapor is adsorbed by the adsorption means. I can do it.

Furthermore, since the float and the solenoid valve are integrally disposed within the fuel tank, the structure of the fuel tank itself is compact, making it convenient to store in a vehicle.

[Brief explanation of drawings]

Figure 1 is a sectional view showing in detail the structure of the solenoid valve and float arranged in the fuel tank in Figure 2;
3 is a sectional view taken along the line - in FIG. 1, FIG. 3 is a view showing the fuel vapor discharge prevention device according to the present invention, and FIG. 4 is a perspective view of the fuel tank shown in FIG. 2. 10... Fuel tank, 22... Charcoal canister, 44... Breather pipe, 54... Solenoid valve, 56... Float, 76, 78... Liquid return wall.

Claims (1)

[Scope of utility model registration request] A fuel tank, a fuel vapor adsorption means, a conduit connecting the fuel tank and the fuel vapor adsorption means and releasing pressure inside the tank during refueling, and a conduit disposed in the middle of the conduit within the fuel tank during refueling. the electromagnetic valve and the float are provided in the fuel tank and close the inner opening of the conduit to define the liquid level of the fuel, and the electromagnetic valve and the float are integrated and installed in the fuel tank A fuel vapor discharge prevention device characterized in that a liquid return wall is provided in a passage between the float and the electromagnetic valve in the conduit.