JP3313252B2 - Evaporation control valve - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an evaporative control system in which fuel vapor generated in a fuel tank is supplied to a canister and the atmosphere can be supplied from the canister side when the pressure in the fuel tank becomes negative. -This is related to the valve.

[0002]

2. Description of the Related Art An evaporative control valve capable of supplying fuel vapor generated in a fuel tank to a canister and supplying air from the canister when the pressure in the fuel tank becomes negative pressure is disclosed, for example, in Japanese Patent Publication No. 6-693
It is publicly known as shown in Japanese Patent Publication No. In this evaporative control valve, a chamber is formed on the upper surface of the diaphragm valve to communicate with the intake manifold, and a spring for urging the diaphragm valve downward is arranged. A tank communicating with the fuel tank is formed on the lower surface of the diaphragm valve. A canister-side chamber communicating with the side chamber and the canister is formed, a slit valve is provided integrally with the diaphragm valve, and the tank-side chamber and the canister-side chamber are communicated via the diaphragm valve or the slit valve.

[0003]

By the way, in the case of the prior art, the upper surface of the diaphragm valve is a chamber communicating with the intake manifold, and the diaphragm valve is opened by the negative pressure of the intake manifold. Therefore, the diaphragm valve is always open during the running of an automobile or the like, and when, for example, a negative pressure is generated in the canister, the negative pressure is introduced into the fuel tank to deform the fuel tank. There is a fear.

The present invention has been made in view of such a problem, and an object of the present invention is to open a diaphragm valve at a desired positive pressure so as to deform a fuel tank by negative pressure. It is an object of the present invention to provide an evaporative control valve capable of preventing the occurrence of a pressure.

[0005]

In order to achieve the above object, an evaporation control valve according to the present invention forms an atmospheric pressure chamber communicating with the atmosphere on the upper surface of a diaphragm valve and urges the diaphragm valve downward. A tank side chamber communicating with the fuel tank and a canister side chamber communicating with the canister are formed on the lower surface of the diaphragm valve, a slit valve is provided integrally with the diaphragm valve, and the tank side chamber and the canister side chamber are connected to each other by a diaphragm valve or so as to communicate with each other through the slit valve, further wherein da
The lower end is formed as a double ring on the upper surface of the diaphragm valve and
A valve holding member with which one end of the spring is in contact is arranged
The lower end of the inner ring of the double ring is longer than the lower end of the outer ring.
It is characterized by being formed well.

[0006]

[0007] The present invention is also characterized in that a plurality of slits are provided in a cap forming the upper surface and side surfaces of the atmospheric pressure chamber, and the atmospheric pressure chamber is communicated with the atmosphere through the slits.

Further, the slit valve pointing toward the tank side chamber is disposed in the inner ring of the double ring of the valve holding member, and a plurality of communication grooves are formed in the inner ring and the fixing portion of the valve holding member. It is also characterized by that.

[0009]

According to the above construction, the pressure in the fuel tank is increased by the fuel vapor, and when the pressure becomes a desired positive pressure that overcomes the urging force of the spring, the diaphragm valve opens and the fuel vapor in the fuel tank opens. To the canister side. Further, when the pressure in the fuel tank becomes lower than the pressure on the canister side, air is sent from the canister side into the fuel tank via the slit valve, and the negative pressure in the fuel tank is prevented.

[0010] Then, the upper surface of the diaphragm valve, the valve pressing member lower end one end of the spring on the upper surface is formed in a double ring is abutting arranged, only down the valve at the lower end of the double chain When the diaphragm valve is opened, the valve holding member is pushed up first, and then the valve seal is pushed up,
Although the valve by the time difference is likely flutter, in the present invention
The lower end of the inner ring of the double ring is formed longer than the lower end of the outer ring to apply tension to the valve seal portion, thereby preventing the valve from fluttering.

When a plurality of slits are provided in a cap forming the upper surface and side surfaces of the atmospheric pressure chamber and the atmospheric pressure chamber communicates with the atmosphere through the slits, the air enters and exits through the slits. Therefore, intrusion of rainwater or the like into the atmospheric pressure chamber is prevented.

Further, the slit valve pointing toward the tank side chamber is disposed in the inner ring of the double ring of the valve holding member, and a plurality of communication grooves are formed in the inner ring and the fixing portion of the valve holding member. In this case, when the pressure in the fuel tank becomes lower than the pressure on the canister side, air is sent from the canister side through the communication groove into the fuel tank through the slit valve,
The air passage and the fixing portion of the valve holding member can be configured at the same place.

[0013]

An embodiment of the present invention will be described with reference to the accompanying drawings. In the figure, reference numeral 1 denotes an evaporation control valve main body. The main body 1 has a fuel tank side communication pipe 2 for attaching a communication pipe to a fuel tank (not shown) and a communication pipe to a canister (not shown). The canister-side communication pipe 3 for attaching the tub is provided. The upper part of the main body 1 is covered with a cap 4.

Reference numeral 5 denotes a diaphragm valve, the periphery of which is sandwiched between the main body 1 and the cap 4. An atmospheric pressure chamber 6 communicating with the atmosphere is formed between the upper surface of the diaphragm valve 5 and the inner surface of the cap 4. A tank side chamber 7 communicating with the fuel tank side communication pipe 2 and a canister side chamber 8 communicating with the canister side communication pipe 3 are formed in the main body 1 on the lower surface of the diaphragm valve 5.
The seal portion 10 of the diaphragm valve 5 is located on a valve seat 9 formed at the upper end of the canister side chamber 8, and the seal portion 1
By 0, the tank side chamber 7 and the canister side chamber 8 are partitioned.

Numeral 11 denotes a slit valve formed integrally with the diaphragm valve 5, which is located inside the seal portion 10. The slit valve 11 is used to supply air from the canister side chamber 8 to the tank side chamber 7. Distribution is allowed.

In the evaporation control valve having the above-described structure, the pressure inside the fuel tank is increased by the evaporated fuel, and this pressure acts to push up the tank side chamber 7 and the diaphragm valve 5. Then, when the pressure becomes a desired positive pressure that overcomes the urging force of the spring 12, the diaphragm valve 5 opens and the tank side chamber 7 sends the evaporated fuel in the fuel tank to the canister side.
From the valve seat 9 and the canister side chamber 8 are formed. When the pressure in the fuel tank becomes lower than the pressure on the canister side, a flow path from the canister side chamber 8 to the tank side chamber 7 is formed via the slit valve 11, and air is sent from the canister side into the fuel tank. Negative pressure in the fuel tank is prevented.

As described above, the pressure in the fuel tank of the diaphragm valve 5 increases, and the pressure
The diaphragm valve 5 does not necessarily open even when the intake manifold becomes a negative pressure during running of an automobile or the like and the canister becomes a negative pressure, for example, when a desired positive pressure that overcomes the biasing force of the vehicle is reached. Since the valve is not opened, the negative pressure on the canister side does not affect the fuel tank.

Reference numeral 13 denotes a valve pressing member disposed on the upper surface of the diaphragm valve 5, and the valve pressing member 13 includes
The lower end is formed in double rings 14 and 15, one end of the spring 12 is in contact with the upper surface 16, and the lower end of the inner ring 14 in the double ring is the lower end of the outer ring 15. It is growing longer. The slit valve 11 is disposed in the inner ring 14 of the valve holding member 13 so as to be directed to the tank-side chamber 7 side.
The lower end presses the valve seal portion 10.
A plurality of communication grooves 17 for air circulation are formed in the inner ring 14, and the double rings 14, 15 are formed near the inner periphery of the outer ring 15.
The plurality of legs 18 projecting further downward than the valve holding member 1
3 are formed as fixed portions, and each leg 18 is composed of two hook portions 19 and 20 and a communication groove 21 for air flow therebetween. Reference numeral 22 denotes a pressing plate that is in contact with the lower surface of the diaphragm valve 5.
The leg 18 is inserted into the hole 23 formed by the
20 is hooked into the hole 23, thereby the valve holding member 1
3, the diaphragm valve 5 and the pressing plate 22 are securely integrated.

[0019] There use such Ben'osae member 13, benshi elongated to the lower end of the outer ring 15 of the lower end of the inner ring 14 of the double chain - compressing the pole tip 10, the valve sheet Since the tension is applied to the seal portion 10, when the diaphragm valve 5 is opened, the valve seal portion 10 follows the rise of the valve holding member 13, so that the diaphragm valve 5 does not flutter. Further, when the pressure in the fuel tank becomes lower than the pressure on the canister side, air is sent from the canister side chamber 8 through the slit valve 11 to the tank side chamber 7 through the communication grooves 17 and 21, but the air passage is formed. Since the groove 21 and the hooks 19 and 20 as fixing portions of the valve holding member are formed on the same leg 18, the formation of the air passage and the fixing of the valve holding member can be easily ensured by a compact structure.

Reference numeral 24 denotes a plurality of slits formed on the periphery of the cap 4 and is an air passage for communicating the atmospheric pressure chamber 6 with the atmosphere. By providing such a plurality of slits 24 in the cap 4, the atmospheric pressure chamber 6
This facilitates the inflow and outflow of air inside the chamber, smoothly operates the diaphragm valve 5, and reliably prevents rainwater and dust from entering the atmospheric pressure chamber 6 from the outside.

Reference numeral 25 denotes a valve for diagnosing a failure of the evaporative control system. When it is desired to intentionally reduce the pressure in the fuel tank to a negative pressure at the time of diagnosing the failure of the system, a negative pressure on the canister side is used. To open the canister and introduce the negative pressure on the canister side to the fuel tank side.

[0022]

As described above, according to the present invention, the atmospheric pressure chamber communicating with the atmosphere is formed on the upper surface of the diaphragm valve, and the spring for urging the diaphragm valve downward is arranged. The fuel tank is provided on the lower surface of the diaphragm valve. Since the tank side chamber communicating with the canister and the canister side chamber communicating with the canister are formed, a slit valve is provided integrally with the diaphragm valve, and the tank side chamber and the canister side chamber are communicated with each other via the diaphragm valve or the slit valve. When the pressure inside the tank increases due to the fuel vapor, and when this pressure reaches a desired positive pressure that overcomes the biasing force of the spring, the diaphragm valve opens to send the fuel vapor inside the fuel tank to the canister side, When the pressure of the canister becomes lower than the pressure on the canister side, the air burns from the canister side through the slit valve. An evaporative control valve that can be sent to the tank to prevent negative pressure in the fuel tank, so that evaporated fuel in the fuel tank can be reliably sent to the canister and that the fuel tank can be reliably prevented from being deformed by negative pressure. It is.

In the above apparatus, a valve holding member is formed on the upper surface of the diaphragm valve, the lower end of which is formed as a double ring, and one end of the spring abuts on the upper surface, and the valve is held at the lower end of the double ring. Therefore , when opening the diaphragm valve,
The flapping of the valve is prevented, and it becomes an evaporative control valve with less noise.

Further, when a plurality of slits are provided in a cap forming the upper surface and side surfaces of the atmospheric pressure chamber and the atmospheric pressure chamber is communicated with the atmosphere through the slits, the air enters and exits through the slits. Therefore, the invasion of rainwater or the like into the atmospheric pressure chamber is prevented, and an evaporative control valve that operates accurately with few failures is provided.

Further, the slit valve pointing toward the tank side chamber is disposed in the inner ring of the double ring of the valve holding member, and a plurality of communication grooves are formed in the inner ring and the fixing portion of the valve holding member. In this case, when the pressure in the fuel tank becomes lower than the pressure on the canister side, air is sent from the canister side through the communication groove into the fuel tank through the slit valve,
Since the air passage and the fixing portion of the valve holding member can be configured at the same place, negative pressure in the fuel tank is reliably prevented, and deformation of the fuel tank is reliably prevented, and the air passage adds special parts. The apparatus can be made compact because it can also be used for the fixed part of the valve holding member without any problem.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of one embodiment of an evaporation control valve according to the present invention.

FIG. 2 is a view in the direction of arrows AA in FIG. 1;

[Explanation of symbols]

 Reference Signs List 4 Cap 5 Diaphragm valve 6 Atmospheric pressure chamber 7 Tank side chamber 8 Canister side chamber 11 Slit valve 12 Spring 13 Valve holding member 14 Inner ring of double ring 15 Outer ring of double ring 17, 21 Communication groove 18 Fixing portion of valve holding member 24 slits

Claims (3)

(57) [Claims] In an evaporation control valve disposed in a pipe connecting a fuel tank and a canister, an atmospheric pressure chamber communicating with the atmosphere is formed on an upper surface of a diaphragm valve, and the diaphragm valve is urged downward. A spring is arranged, a tank side chamber communicating with the fuel tank and a canister side chamber communicating with the canister are formed on the lower surface of the diaphragm valve, a slit valve is provided integrally with the diaphragm valve, and the tank side chamber and the canister side chamber are connected with the diaphragm valve or the slit. Communicate through a valve , and
The lower end is formed as a double ring on the upper surface of the diaphragm valve.
The valve holding member with which one end of the spring is in contact
The lower end of the inner ring of the double ring is longer than the lower end of the outer ring.
An evaporation control valve characterized by being formed well. 2. A key forming an upper surface and side surfaces of the atmospheric pressure chamber.
The cap is provided with a plurality of slits and large
2. The evaporative control valve according to claim 1, wherein the pressure chamber communicates with the atmosphere . 3. A tank in the inner ring of the double ring of the valve holding member.
Disposing the slit valve directed to the side chamber side, the inner ring and the
A plurality of communication grooves are formed in the fixing part of the valve holding member
The evaporative control bar according to claim 1, wherein
Lube .