JPS599077Y2 - Fuel evaporative gas emission control device - Google Patents

Description

[Detailed description of the invention] The present invention relates to an improvement of a fuel evaporative gas emission suppressing device that prevents evaporative gases generated from fuel systems such as fuel tanks from being released into the atmosphere by adsorbing them onto activated carbon while an automobile engine is stopped. It is something.

Conventionally, as this type of fuel evaporative gas emission control device, a canister type device has activated carbon 3 housed inside a canister housing 2, as shown in FIG. It is opened to the atmosphere as a purge air intake, and has an evaporative gas supply port 4 and a purge control valve 5 at the top.
It is equipped with.

The supply port 4 is communicated with a fuel tank etc. via a passage 8 having a check valve 6. When the fuel tank 7 is warmed due to an increase in outside air temperature and the pressure inside the tank exceeds a specified level, the check valve is opened. 6 opens to supply evaporative gas from the fuel in the fuel tank 7 to the canister 1.

Further, the purge control valve 5 is configured to open and close the valve port 11 by moving the valve body 10 of the diaphragm 9 by the negative pressure in the valve operation negative pressure chamber 12, and the valve operation negative pressure chamber 12 opens and closes the passage 13. The chamber 17 communicates with the port 16 slightly upstream of the idling opening position of the throttle valve 15 in the carburetor 14 through the valve, and communicates with the valve port 11 when the small-diameter port 22 and the valve body 10 are opened. The intake pipe 2 of the intake system is connected by a passage 19 having 18
It communicates with a port 21 such as 0 or the like.

With this structure, when the engine is stopped, evaporated fuel gas generated in the fuel tank 7 is automatically and appropriately supplied into the canister 1, where the activated carbon 3 adsorbs gasoline.

On the other hand, when the internal combustion engine is stopped, the check valve 18 is closed, thereby blocking the canister 1 and the intake pipe 20. However, when the internal combustion engine is operated, the intake negative pressure is reversed. It acts on the stop valve 18 to open it.

When the opening degree of the throttle valve 15 is small, such as during idling or deceleration operation, the purge control valve 5 operates because the valve operation negative pressure chamber 12 becomes atmospheric pressure and the valve body 10 closes the valve port 11. , a small amount of gasoline adsorbed on the activated carbon in canister 1 is transferred to small diameter port 2.
2 and is sucked into the intake pipe 20.

Next, when the opening degree of the throttle valve 15 increases, negative pressure acts on the valve operation negative pressure chamber 12 of the purge control valve 5, opening the valve port 11, thereby increasing the amount of purge from the canister 1. It becomes like this.

By the way, as mentioned above, in the canister 1, the evaporative gas supply port 4 and the purge control valve 5 are installed side by side in the upper part of the housing 2, and there is an appropriate gap between these and the activated carbon 3. Only.

Therefore, although the evaporated gas supplied from the supply port 4 spreads somewhat radially, it is locally supplied to the activated carbon in the extension line of the supply port 4 and charged there.

Therefore, in reality, the supply port 4 is used for the entire area of the activated carbon 3.
It is only charged in a limited area on the side, and the amount of charge for the entire area is small.

On the other hand, when the activated carbon 3 is purged in the same way, the suction force passing through the purge control valve 5 acts only on the part on the extension line of the valve 5, so the activated carbon 3
Purging is performed from a limited area on the side of the purge control valve 5 with respect to the entire area, and the amount of purging is also small.

In this way, in the activated carbon 3 of the canister 1, charging and purging are performed locally and the amount thereof is small, so when the amount of evaporated gas from fuel from the fuel tank etc. is large, a part of the evaporated gas is The disadvantage is that the gasoline is not adsorbed by the activated carbon and is emitted into the atmosphere.

In view of these circumstances, the present invention provides an improved fuel evaporative gas emission suppressing device that charges and purges the entire area of the activated carbon in the canister to increase the amount of charging and purging.

To achieve this purpose, the device of the present invention provides a hemispherical lid between the evaporative gas supply port and purge control valve and the activated carbon inside the canister housing.
The lid is provided with a distribution hole whose diameter increases toward the outside so that the evaporated gas introduced from the supply port reaches the entire area of the activated carbon. It is characterized by a shape that guides you in the direction.

In addition, as an example of prior art regarding this,
The microfilm (issued by the Japan Patent Office on January 29, 1972) that captured the contents of the specification and drawings attached to the application No. 9254 (Utility Model Application No. 52-13318) shows the fuel tank, carburetor float chamber, etc. The evaporated gas generated from multiple locations is introduced into the activated carbon by inserting and connecting each introduction pipe into each chamber formed in the activated carbon layer of the canister and partitioned by a wall and surrounded by a perforated plate or wire mesh. Pressure changes in the above evaporative gas generation source that occur when the evaporative gas from the above sources is collected in one introduction pipe and guided to the canister, or due to poor seating of the control valve of the introduction pipe width. This prevents the evaporative gas from leaking directly into the atmosphere from one source of evaporative gas to the other without being adsorbed by the canister due to pressure differences between the sources due to leakage or the like. What was done is listed.

Embodiments of the present invention will be specifically described below with reference to the drawings.

FIG. 2 shows an embodiment of the present invention, in which a canister 1 has an evaporative gas supply port 4 and a purge control valve 5, as in the case of FIG. A hemispherical lid 23 is provided between the purge control valve 5 and the activated carbon 3, and this lid 23 is provided with a large number of distribution holes 24 whose diameter increases toward the outside.

Thus, since the present invention is constructed as described above,
The evaporated gas supplied from the fuel tank 7 to the inside of the canister housing 2 via the check valve 6 and the supply port 4 spreads to the outer periphery along the surface of the hemispherical lid 23. Coupled with the fact that the diameter of the distribution hole 24 becomes larger toward the periphery, the activated carbon 3 in the canister 1 is distributed and supplied to the entire area, and as a result, the activated carbon 3 is charged over the entire area. be done.

In addition, when the internal combustion engine is operating, the suction force from the purge control valve 5 extends along the hemispherical lid to the outer periphery, and the diameter of the distribution hole 24 increases toward the periphery. As a result, the active carbon 3 acts on the entire area of the activated carbon 3, and the gasoline adsorbed thereon is led to the purge control valve 5 and purged.

As described above, according to the present invention, charging and purging are performed throughout the activated carbon 3 of the canister 1, increasing the operating area and greatly increasing the amount of charging and purging.
Even if the amount of evaporated gas increases, its release into the atmosphere is prevented.

Furthermore, since the activated carbon 3 itself is used evenly over the entire area, the life of the activated carbon is extended compared to the conventional activated carbon that is used locally.

[Brief explanation of drawings]

FIG. 1 is a structural diagram showing a conventional fuel evaporative gas emission control device, and FIG. 2 is a sectional view showing a main part of an embodiment of the present invention. 1... Canister, 2... Housing, 3... Activated carbon,
4... Supply port, 5... Purge control valve, 6, 18... Check valve, 7... Fuel tank, 8
,13.19...passage, 9...diaphragm, 10
...Variation, 11...Valve port, 12...Valve operation negative pressure chamber, 14...Carburizer, 15...Throttle valve, 16,21. 22...Port, 17...Room, 2
0...Intake pipe, 23...Lid, 24...Distribution hole.

Claims (1)

[Scope of utility model registration request] In a fuel evaporative gas emission control device, which is provided with an evaporative gas supply port communicating with a fuel system and a purge control valve connected to an intake system of an internal combustion engine in the upper part of a canister casing containing activated carbon, the inside of the canister casing A hemispherical lid is provided between the activated carbon, the vaporized gas supply port, and the purge control valve, and the lid is provided with a distribution hole that increases in diameter toward the outside,
A fuel evaporator characterized in that the evaporative gas introduced from the supply port is made to cover the entire area of the activated carbon, and the adsorbed gasoline is guided from the entire area of the activated carbon to the purge control valve. Gas emission suppression device.