JPH0552153A - Fuel outflow preventing device - Google Patents

Abstract

PURPOSE:To prevent a canister from deteriorating by an inflow of fluid fuel into the canister at the time of a full tank while air pollution by adsorbing fuel vapor, generated in a tank, to the canister, also during fueling. CONSTITUTION:In the case of a fuel system of an internal combustion engine in which an air chamber 14 is formed in an upper part of a fuel tank 1 so as to discharge fuel vapor in the tank 1 through a canister 3, an opening/closing valve 9, which is closed when a fuel lid 12 or a tank cap 13 is opened and further when the tank is fully filled with fuel and opened except in the above- mentioned condition, is provided on the halfway of a fuel vapor passage 2 of connecting the fuel tank 1 to the canister 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel outflow device for a fuel system of an internal combustion engine.

[0002]

2. Description of the Related Art When discharging fuel vapor from the upper portion of a fuel tank, the fuel vapor is adsorbed to a canister and then discharged from the viewpoint of exhaust regulation. However, since the fuel tank generally has a fuel filler port higher than the canister, when the fuel filler tank is filled with fuel, the fuel flows into the canister due to the difference in gravity. Therefore, conventionally, a check valve (usually a one-way valve that opens when the internal pressure of the fuel tank becomes 300 mmAg or more) is provided in the middle of the fuel vapor passage that connects the fuel tank and the canister. A chamber is formed to prevent fuel from flowing out to the canister even when the tank is full.

However, since such a check valve is arranged, internal pressure acts inside the fuel tank and in the fuel pipe. It is often difficult to restart the engine when the engine room temperature is high during the summer or after heavy load operation, but it is difficult for the engine to restart. It is also caused by the fact that it accumulates in the intake passage through the valve, or bar collation occurs in the fuel passage in the carburetor and jumps out into the intake manifold. However, the biggest factor that makes restartability difficult is that the fuel pipe between the carburetor and the fuel tank is heated when the engine is stopped, the fuel during this period is vaporized, and the fuel in the float chamber evaporates, causing the float chamber level to rise. This is because the fuel vapor in the fuel pipe or fuel tank is pushed down into the float chamber by the pressure in the tank or the volume change when vaporized, and is sent into the intake manifold from the air pent pipe.

Therefore, the above problems can be solved by releasing the internal pressure of the fuel tank. However, when the check valve is removed and the tank internal pressure is constantly released, fuel will flow into the canister when the tank is filled with oil.

In order to solve such a contradiction, the internal pressure of the fuel tank is controlled to improve the restartability of the engine at high temperature and prevent the fuel from flowing into the canister. Is the actual development 55-
It is proposed in Japanese Patent No. 106356.

In this fuel tank internal pressure control device, an air chamber 14 is formed in the upper portion of the fuel tank 1 as shown in FIG. 3, and the fuel vapor in the tank is discharged through the canister 3 in the fuel system of the internal combustion engine. In the middle of the fuel vapor passage 2 connecting the fuel tank 1 and the canister 3, there is provided an opening / closing valve 9 which opens when the fuel tank filler cap (cap) 13 is closed and closes when the fuel filler opening is opened. There is.

Reference numeral 4 is a vaporizer, 5 is a float chamber, 6 is a fuel supply pipe, 7 is a fuel pump, 8 is a return pipe for returning fuel vapor generated in the middle of the fuel pipe 6 to the fuel tank 1, and 10 is a fuel tank cap. A switch that works together with the switch 13. When the cap 13 is opened, that is, during refueling, the switch 10
Is closed to energize, and the on-off valve (solenoid valve) 9 is closed to shut off the fuel vapor passage 2.

[0008]

In the prior art shown in FIG. 3, the fuel vapor passage connecting from the fuel tank to the canister is closed while the fuel cap is open. Since all of the vapor comes out of the fuel filler port, all of the components of the fuel vapor, HC, are released from the fuel filler port to the atmosphere, causing fuel odor and polluting the atmosphere.

Further, since the on-off valve of the fuel vapor passage connecting the fuel tank and the canister is left open except when the fuel is refilled, when the vehicle body is greatly tilted or falls, liquid fuel flows into the canister or passes through the canister. Since it leaks to the outside, there is a problem that the canister deteriorates, the adsorption rate of fuel vapor deteriorates, polluting the atmosphere and leaking fuel, which is dangerous.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a fuel outflow prevention device that solves such problems.

[0011]

In order to achieve the above object, the fuel outflow prevention device of the present invention has an air chamber (14) formed in an upper portion of a fuel tank (1), and a fuel vapor in the tank (1) is formed. In the fuel system of the internal combustion engine in which the fuel is discharged through the canister (3), a fuel lid (12) or a tank cap (12) is provided in the fuel vapor passage (2) connecting the fuel tank (1) and the canister (3). An on-off valve (9) is provided which is closed when 13) is open and the fuel is full, and is opened at other times.

It is effective to provide a rollover valve (17) which is closed at a certain inclination or more at the tank side inlet of the fuel vapor passage (2) connecting the fuel tank (1) and the canister (3).

[0013]

[Function] Even if fuel is being supplied with the fuel lid or tank cap open, if the fuel is not filled, the on-off valve opens the fuel vapor passage from the fuel tank to the canister, so the fuel generated in the tank Can absorb vapor into the canister.

Even when the fuel is filled up to near the upper end during refueling, an air chamber remains in the upper part of the fuel tank and the fuel does not flow out to the canister. When the vehicle body tilts or falls, the rollover valve is closed and the fuel vapor passage is blocked.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the invention is shown in FIG. The fuel lid 12 of the vehicle body 1 is provided with a first switch 10 which is interlocked with the fuel lid 12 and which is turned on when the fuel lid 12 is opened during refueling. The fuel tank 1 has a float 15 as a sensor for measuring the amount of fuel, and is provided with a second switch 16 which is interlocked with the float 15 and is turned on when the fuel is full. Further, an air chamber 14 is provided at the upper part of the fuel tank 1, and the air chamber 14 is
It has a volume that does not overflow even if the filled fuel flows into the fuel filler port. A fuel vapor passage 2 connects the air chamber 14 to the canister 3, and the fuel tank 1 in the passage 2 is connected to the canister 3.
Rollover valve 1 that closes at a certain angle on the side
7 is provided. A solenoid valve 9, which is an on-off valve that closes the passage 2 when the first switch 10 and the second switch 16 are turned on, is provided in the middle of the fuel vapor passage 2. Further, the canister 3 does not have a check valve, but has a passage 19 leading to the throttle body 18 and a passage 20 open to the atmosphere.

Next, the operation of the first embodiment will be described. Since the fuel lid 12 is opened during refueling, the first switch 10 is turned on. However, fuel tank 1
When the amount of fuel inside is small, the float 15 is lowered and the second switch 16 is turned off. Therefore, the solenoid valve 9 in the middle of the fuel vapor passage 2 is open. Therefore, since the fuel tank 1 and the canister 3 are connected to each other, the fuel vapor generated during refueling can be adsorbed to the canister 3.

When the fuel is refueled and the tank is full, the float 15 rises, so the second switch 16 is turned on and the solenoid valve 9 is closed. Therefore, the air chamber 1 above the fuel tank 1
In No. 4, since the passage 2 is cut off and the internal pressure rises, fuel does not enter.

Fuel is filled up to the vicinity of the upper end of the fuel filler port, refueling is completed, the fuel lid 12 is closed, and the solenoid valve 9 is closed.
Since the air chamber 14 has a sufficient volume even when the fuel cell is opened, the fuel does not overflow from the tank 1 to the canister 3 even when the fuel in the fuel filler portion flows in. Therefore, deterioration of the canister due to the inflow of liquid fuel can be prevented.

When the vehicle body tilts or falls, the solenoid valve 9 remains open, but the fuel vapor passage 12 is closed by the rollover valve 17 at the inlet of the fuel vapor passage 2, so that the liquid vapor The fuel is prevented from flowing into the canister 3 or leaking to the outside through the canister 3.

FIG. 2 shows a second embodiment. This is the first
Compared with the embodiment, the first switch 10 which is turned on and off in conjunction with opening and closing of the fuel lid 12 is replaced with the first switch 10 which is turned on and off in association with opening and closing of the tank cap 13. Other configurations and operations are the same as those in the first embodiment, and thus the description thereof will be omitted.

[0021]

Since the fuel outflow prevention device of the present invention is constructed as described above, it is possible to adsorb the fuel vapor generated during fuel refueling and reduce the amount of fuel vapor leaking out from the refueling port. Therefore, air pollution can be prevented.

Further, since the liquid gasoline does not flow into the canister, deterioration of the canister can be prevented. Then, the fuel vapor being refueled can be adsorbed to the canister and used as fuel for the internal combustion engine, which improves fuel economy.

Furthermore, when the vehicle body tilts or falls, the fuel vapor passage is closed by the rollover valve, so that the leakage of fuel to the outside can be prevented.

[Brief description of drawings]

FIG. 1 is a schematic diagram of a first embodiment of the present invention.

FIG. 2 is a schematic diagram of a second embodiment of the present invention.

FIG. 3 is a schematic diagram of a conventional technique.

[Explanation of symbols]

 1 Fuel tank 2 Fuel vapor passage 3 Canister 9 Open / close valve (solenoid valve) 12 Fuel lid 13 Tank cap 14 Air chamber 17 Rollover valve

[Procedure amendment]

[Submission date] September 11, 1991

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0014

[Correction method] Change

[Correction content]

Further, even when the fuel is filled up to the vicinity of the upper end of the fuel filling port , the air chamber remains in the upper portion of the fuel tank, and the fuel does not flow out to the canister. When the vehicle falls down or tilted, the rollover valve is closed, the fuel vapor passage path is blocked.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0015

[Correction method] Change

[Correction content]

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the invention is shown in FIG. The fuel lid 12 of the vehicle body 11 is provided with a first switch 10 which is in communication with the fuel lid 12 and which is turned on when the fuel lid 12 is opened during refueling. The fuel tank 1 has a float 15 as a sensor for measuring the amount of fuel,
Comprising a second switch 1-6, the ON when in conjunction with the float 15 the fuel becomes full. Also, the fuel tank 1
Is provided with an air chamber 14 at the upper part thereof, and the air chamber 14 has a volume that does not overflow even if the fuel filled up to the fuel filling port flows in. A fuel vapor passage 2 is connected from the air chamber 14 to the canister 3, and a rollover valve 17 that is closed to the fuel tank 1 side of the passage 2 at a certain inclination or more.
Is provided. A solenoid valve 9, which is an opening / closing valve that closes the passage 2 when the first switch 10 and the second switch 16 are turned on, is provided in the middle of the fuel vapor passage 2. The canister 3 does not have a check valve but has a passage 19 leading to the throttle body 18 and a passage 20 open to the atmosphere.

Claims (2)

[Claims] 1. An air chamber (14) is formed in an upper part of a fuel tank (1), and fuel vapor in the tank (1) is transferred to a canister (3).
In a fuel system of an internal combustion engine, which is configured to discharge via a fuel cell, a fuel lid (12) or a tank cap (13) opens in the middle of a fuel vapor passage (2) connecting a fuel tank (1) and a canister (3). A fuel outflow prevention device provided with an on-off valve (9) which is closed when the fuel is full and is opened at other times. 2. The fuel according to claim 1, wherein a roll-over valve (17) which is closed at a certain slope or more is provided at the tank side inlet of the fuel vapor passage (2) connecting the fuel tank (1) and the canister (3). Spill prevention device.