JP3531300B2 - Fuel vapor emission control device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel vapor discharge control device for controlling the fuel vapor pressure in a fuel tank.

[0002]

2. Description of the Related Art FIG. 4 is a diagram for explaining the structure of a conventional fuel vapor discharge control device 101 for controlling the fuel vapor pressure in a fuel tank in an automobile equipped with an engine that uses gasoline, light oil or the like as a fuel.

The fuel tanks and fuel systems of automobiles are important safety parts and are subject to legal regulations such as safety regulations regarding fuel leakage and fire occurrence at the time of collision, and pollution regulations for preventing fuel vapor from being released into the atmosphere. In addition, from the viewpoint of safety and pollution prevention, it is necessary to consider various points so that fuel does not leak even when the vehicle leans or turns.

Particularly, in recent years, reducing the amount of fuel vapor released to the atmosphere has become one of the important problems, and it is desired that one not release a trace amount of vapor.

In the fuel vapor emission control device 101 shown in FIG.
At the time of fuel refueling, the pressure inside the fuel tank 102 rises, the main diaphragm 103a of the main differential pressure valve 103 opens to open the vent line 105, and leads to the canister 120 which absorbs the generated fuel vapor. Then, when the liquid level of the fuel rises along with the refueling, the vent valve 106 rises due to buoyancy and closes the vent line 105.

When the vent line 105 is closed at the time of refueling, the fuel vapor generated is refueled by the refueling port 11 of the fuel pipe 111.
1a and the upper portion of the fuel tank 102 are communicated with each other through a breather pipe 112 and a fuel cut-off valve 107, and an outflow line 108 flows out.

However, the breather pipe 112 is very thin as compared with the diameter of the fuel pipe 111, and in order to discharge the air in the fuel tank corresponding to the large amount of fuel to be refueled to the outside of the fuel tank 102. It is impossible, and the pressure inside the fuel tank 102 rises.

Then, the evaporation line 10 which is not closed by the fuel cutoff valve 107 at this time point.
This pressure is applied to the sub-diaphragm 110 of the sub-differential pressure valve 109 by the signal line 113 that is piped from the No. 8 and the fuel supply port 111a, and the sub-differential pressure valve 109 is opened to reduce the pressure inside the fuel tank.

After the vent line 105 is closed, it is necessary to raise the liquid level in the refueling pipe 111 in order to activate the automatic stop function of the refueling gun (not shown). By gradually setting the pressure decrease rate, the liquid level in the oil supply pipe 111 rises when the oil supply is continued, and the automatic stop function of the oil supply gun operates.

Further, since fuel cutoff valve 107 closes evaporation line 108 when fuel is supplied, pressure is not applied to sub diaphragm 110 of sub differential pressure valve 109, and sub differential pressure valve 109 is closed to close fuel tank 102. Even if refueling is performed after the internal pressure drop rate is further reduced and the auto stop function is activated, the auto stop function is activated immediately, the fuel filler is notified of full fuel, and the fuel supply is terminated.

Further, in the normal state, the fuel filler portion 111a is closed by the fuel cap, so that the fuel tank 102 is closed.
When the internal pressure rises, the pressure from the signal line 113 connected to the evaporation line 108 and the oil supply port 111a is applied to the sub diaphragm 110, and the sub differential pressure valve 10
9 is opened to reduce the pressure inside the fuel tank 102.

[0012]

FIG. 5 is a diagram showing in detail the structure of the main differential pressure valve 103 and the auxiliary differential pressure valve 109 which are used in the fuel vapor discharge control device 101 having the above-mentioned configuration of the prior art.

In the prior art, in order to open the auxiliary differential pressure valve 109, the evaporation line 108 and the oil supply port portion 111a.
The pressure of the signal line 113, which is further connected, is used together, and at the same time, the fuel vapor from both lines is exhausted to the canister 120.

Therefore, it is necessary to bring the pressure of the sub-diaphragm chamber 114 for opening the sub-differential pressure valve 109 to the atmospheric pressure state, and the sub-diaphragm chamber 114 is provided with the atmospheric port 115 to communicate with the atmospheric side. .

However, the sub-diaphragm 110 is generally formed of a thin film of a rubber-like elastic body,
There is a problem that the fuel vapor permeates between the molecules of the thin film and the fuel vapor evaporates into the atmosphere through the atmosphere port 115.

Further, there is a diaphragm having a structure in which a film is attached to the surface of a thin film of a rubber-like elastic material in order to prevent permeation of the film, but this has a large drag force, and a large differential pressure is required to drive the diaphragm. Is required, it is difficult to use it in a place such as a fuel tank where a slight differential pressure operation is required.

The present invention has been made to solve the above-mentioned problems of the prior art. The object of the present invention is that the fuel that permeates through the diaphragm of the differential pressure valve used for controlling the pressure of the fuel tank is in the atmosphere. It is an object of the present invention to provide a fuel vapor discharge control device having a structure that does not evaporate into the interior.

[0018]

In order to achieve the above object, in the present invention, an oil supply pipe connecting an upper part of a fuel tank and an oil supply port, and an oil supply port of the oil supply pipe and an upper part of the fuel tank are made to communicate with each other. Attached to a fuel tank with a breather pipe,
A main differential pressure valve that is disposed in the main exhaust passage of the fuel tank and is biased in the valve closing direction to open due to an increase in pressure in the tank during refueling to discharge fuel vapor; Passes through each of the exhaust flow paths and the auxiliary differential pressure valve that is installed in the auxiliary exhaust flow path connected to the oil supply port of the pipe and discharges fuel vapor when the tank is closed by the valve body that is biased in the valve opening direction. A fuel vapor discharge control device comprising a canister for absorbing the fuel vapor discharged as a result and a vent valve for closing the main exhaust passage by raising the liquid level in the fuel tank, A main differential pressure valve valve chamber that drives the pressure valve communicates with the auxiliary exhaust flow passage, and a sub differential pressure valve valve chamber that drives the auxiliary differential pressure valve communicates with an upper portion of the fuel tank.

However, the main differential pressure valve and the sub differential pressure valve are diaphragm valves having a rubber-like elastic diaphragm, and the valve body formed on the diaphragm is a valve seat consisting of one end face of a cylindrical exhaust passage. It is also preferable to control the discharge of the fuel vapor by connecting and disconnecting with.

It is also preferable that the main differential pressure valve and the sub differential pressure valve are hierarchically arranged in a cylindrical housing, and the main differential pressure valve valve chamber and the auxiliary exhaust flow path are both used.

[0021]

In the present invention constructed as described above, the main differential pressure valve is urged in the closing direction to be closed and the auxiliary differential pressure valve is opened in the normal state when the pressure inside the tank is not increased. It is urged to open.

During refueling, the pressure inside the fuel tank rises and the main differential pressure valve opens, so the discharged fuel vapor is guided to the canister.

When the liquid level rises due to refueling, the vent valve closes the main exhaust passage, so that the pressure inside the fuel tank does not drop and pressure is applied to the sub differential pressure valve valve chamber communicating with the upper part of the fuel tank. , Drive the auxiliary differential pressure valve in the closing direction.
Then, since the auxiliary exhaust passage is closed, the internal pressure of the fuel tank is not reduced and the liquid level of the fuel supply pipe rises to activate the automatic stop of the fuel supply gun.

Next, when the fuel tank becomes full and the pressure in the fuel tank rises after the refueling cap is closed, the pressure inside the tank rises above and below the sub-diaphragm, that is, in the main differential pressure valve chamber and the sub exhaust passage, respectively. As a result, the pressure is equilibrium, but the auxiliary differential pressure valve is biased in the opening direction, so the auxiliary exhaust flow path opens, and fuel vapor flows from the inside of the fuel tank to the breather pipe and the fuel port of the fuel pipe. And the sub-exhaust flow path to flow to the canister and reduce the fuel tank pressure.

In the pressure control of the fuel vapor, the main and auxiliary differential pressure valves and the valve chamber have no atmosphere opening port communicating with the atmosphere, and the fuel vapor passing through the diaphragm flows to the canister side. There is no evaporation of fuel vapors into the atmosphere.

Since the main differential pressure valve and the sub differential pressure valve are diaphragm valves having a rubber-like elastic diaphragm, the valves are opened and closed with a slight differential pressure.

Further, by arranging the main differential pressure valve and the auxiliary differential pressure valve in a cylindrical housing in a hierarchical manner, the main differential pressure valve valve chamber and the auxiliary exhaust flow passage, both of which commonly use the same pressure, are also used. Will be possible.

[0028]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure of a fuel vapor discharge control device to which the present invention is applied will be described below with reference to FIGS.

FIG. 1 shows a fuel vapor discharge control device 1 according to the present invention.
Which is a part of the constituent elements of the present invention and is a feature of the present invention, and is a sectional explanatory view of the fuel vapor discharge control valve 2 in which the main differential pressure valve 3 and the auxiliary differential pressure valve 4 are hierarchically arranged in the housing 11. Is.

The fuel vapor discharge control valve 2 is used to control the fuel vapor pressure in the fuel tank 30 shown in FIG. 2, and the fuel tank 30 and the fuel vapor discharge control device 1 associated therewith. Is prepared for.

The main differential pressure valve 3 is arranged in the main exhaust flow passage 5 of the fuel tank, and has a valve body 7 that abuts against a valve seat 6 formed of one end face of the main exhaust flow passage 5 having a cylindrical shape, and this valve. Body 7
And a main differential pressure valve valve chamber 9 that applies pressure to the diaphragm 8 and a spring 10 that is a biasing means that biases the valve body 7 in the closing direction.

Further, the canister 4 for absorbing the exhausted fuel vapor is provided downstream of the valve seat 6 in the main exhaust passage 5.
The vent line 12 is connected to 0, and the reference numeral 34 is a vent valve that closes the main exhaust passage 5 due to the rise of the liquid level. The main differential pressure valve valve chamber 9 is connected to the sub exhaust passage 33.

The auxiliary differential pressure valve 4 is arranged in an auxiliary exhaust passage 33 connected to the oil supply port portion 32 of the oil supply pipe 31.

The sub-exhaust flow passage 33 is connected to the inside of the housing 11 of the fuel vapor discharge control valve 2, and concentrically from the opening of the cylindrical portion 13 formed inside the housing 11 from the outer flow passage 33a to the inner flow passage 33b. And flow, auxiliary vent line 1
It is connected to the vent line 12 via 4.

The auxiliary differential pressure valve 4 includes a valve body 16 that abuts on a valve seat 15 formed of the end face of the cylindrical portion 13, a diaphragm 17 that moves the valve body 16 while holding it, and a secondary differential pressure that applies pressure to the diaphragm 17. Pressure valve valve chamber 18, valve body 1
And a spring 19 which is a biasing means for biasing 6 in the opening direction.

The auxiliary differential pressure valve valve chamber 18 is connected to the fuel tank 3
0 is connected to the upper part, and in this embodiment,
An FCV line 36 is connected to an upper portion of the fuel tank 30 via a fuel cutoff valve (hereinafter referred to as FCV) 35 provided on the upper portion of the fuel tank 30.

Further, in the present embodiment, the main differential pressure valve 3 and the auxiliary differential pressure valve 4 are hierarchically arranged in the housing 11 and are integrally constructed. With this configuration, each of them is inside the fuel tank 30. It is possible to use both the main differential pressure valve valve chamber 9 and the sub-exhaust passage 33 that commonly use the same pressure.

The diaphragms 8 and 17 are made of a thin film of a rubber-like elastic material for opening and closing the valve with a slight differential pressure, but the material is not limited to this material.

Next, the operation of the fuel vapor discharge control device 1 in the embodiment thus constructed will be described with reference to FIG.

First, in a normal state where the pressure inside the fuel tank 30 does not rise, the main differential pressure valve 3 is biased and closed by the spring 10 in the closing direction, and the auxiliary differential pressure valve 4 is opened in the opening direction by the spring 19. It is urged to open.

FIG. 3 (a) shows the state during refueling.
When the pressure inside the fuel tank 30 rises as fuel is supplied, the main differential pressure valve opens, and the fuel vapor flows into the vent line 12 and is guided to the canister 40.

When the liquid level rises due to refueling, FIG. 3 (b)
As described above, since the vent valve 34 closes the main exhaust flow passage 5, the pressure inside the fuel tank 30 does not decrease, and pressure is applied to the sub differential pressure valve chamber 18 communicating with the upper portion of the fuel tank 30. 4 is driven in the closing direction. Then, since the auxiliary exhaust flow path 33 is closed, the internal pressure of the fuel tank 30 is not reduced, and the liquid level of the oil supply pipe 31 rises to increase the oil supply gun 50.
The automatic stop of is activated.

Next, the refueling tank 30 becomes full,
When the pressure in the fuel tank 30 rises after the refueling cap 38 is closed, as shown in FIG. 3 (c), the breather pipe 37 is passed through the diaphragm 17 of the auxiliary differential pressure valve 4, above and below the diaphragm 17.
That is, since the pressure inside the tank 30 is applied to the main differential pressure valve valve chamber 9 and the auxiliary exhaust flow path 33, respectively, the pressure state is in equilibrium, but the auxiliary differential pressure valve 4 is biased in the opening direction. The flow path 33 is opened, and the fuel vapor is supplied to the fuel tank 3.
The breather pipe 37, the fuel supply port 32 of the fuel pipe, the auxiliary exhaust passage 33, the auxiliary vent line 14, the vent line 12
And the pressure in the fuel tank 30 is reduced.

In the above fuel vapor pressure control, the main and auxiliary differential pressure valves 3 and 4 and the valve chambers 9 and 18 do not have an atmosphere opening port that communicates with the atmosphere, and fuel vapor that permeates any of the diaphragms canister. Since it flows into the vent line 12 or the auxiliary vent line 14 flowing to the 40 side, there is no evaporation of fuel vapor into the atmosphere.

[0045]

The present invention having the above-described structure and operation controls the pressure of fuel vapor without providing an atmospheric port in the differential pressure valve chamber of the differential pressure control valve used in the fuel vapor discharge control device. Therefore, even if the fuel vapor permeates the diaphragm, it is discharged to the canister side, so that the fuel vapor does not evaporate into the atmosphere.

Since the main differential pressure valve and the sub differential pressure valve are diaphragm valves having a rubber-like elastic diaphragm, the valves are opened and closed with a slight differential pressure.

Further, by arranging the main differential pressure valve and the auxiliary differential pressure valve in a hierarchical manner in the cylindrical housing, the main differential pressure valve valve chamber and the auxiliary exhaust flow passage both share the same pressure. Therefore, the apparatus can be downsized and the piping can be simplified.

[Brief description of drawings]

FIG. 1 is a cross-sectional explanatory view of a fuel vapor discharge control valve according to the present invention.

FIG. 2 is a diagram illustrating a configuration of a fuel vapor discharge control device according to the present invention.

FIG. 3 is a diagram for explaining the operation of the fuel vapor discharge control device according to the present invention during refueling, when the tank is full, and when the pressure is increasing.

FIG. 4 is a diagram illustrating a configuration of a conventional fuel vapor emission control device.

FIG. 5 is a cross-sectional explanatory view of a conventional fuel vapor discharge control valve.

[Explanation of symbols]

1 Fuel vapor emission control device 2 Fuel vapor discharge control valve 3 Main differential pressure valve 4 Sub differential pressure valve 5 Main exhaust flow path 6 valve seats 7 valve body 8 diaphragm 9 Main differential pressure valve chamber 10 springs 11 housing 12 Bent line 13 Cylindrical part 14 Vent line 15 valve seat 16 valve body 17 diaphragm 18 Sub differential pressure valve chamber 19 spring 30 fuel tank 31 Oil supply pipe 32 Filling port 33 Secondary exhaust flow path 34 Vent valve 35 fuel cut-off valve (FCV) 36 FCV line 37 Breather Tube 40 canister 50 refueling gun

Claims (3)

(57) [Claims] 1. A fuel tank provided with a fuel supply pipe connecting an upper part of the fuel tank and a fuel supply port, and a breather pipe communicating the fuel supply port part of the fuel supply pipe with an upper part of the fuel tank. A main differential pressure valve, which is disposed in the flow path and is urged in the valve closing direction, opens when the pressure in the tank rises during refueling and discharges fuel vapor; and a refueling port of the refueling pipe. Secondary differential pressure valves that are installed in the secondary exhaust flow paths connected to each other and that discharge the fuel vapor when the tank is sealed by the valve element that is biased in the valve opening direction, and the fuel that is discharged through each exhaust flow path. A fuel vapor discharge control device comprising: a canister that absorbs vapor; and a vent valve that closes the main exhaust passage when the liquid level in a fuel tank rises. The pressure valve valve chamber communicates with the sub exhaust passage, The fuel vapor discharge control device, wherein the driven sub differential pressure valve valve chamber communicates with the upper portion of the fuel tank. 2. The main differential pressure valve and the sub differential pressure valve are diaphragm valves having a rubber-like elastic diaphragm,
2. The fuel vapor discharge control device according to claim 1, wherein the valve body formed on the diaphragm controls the discharge of the fuel vapor by engaging and disengaging with the valve seat formed of one end face of the cylindrical exhaust passage. . 3. The main differential pressure valve and the auxiliary differential pressure valve are hierarchically arranged in a cylindrical housing, and the main differential pressure valve valve chamber and the auxiliary exhaust flow path are both used. 3. The fuel vapor emission control device according to 1 or 2.