JPH09177619A - Evaporated fuel processing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To evenly absorb evaporated fuel by absorbent of a canister, thereby enhance an absorbing efficiency, concurrently purge absorbed evaporated fuel uniformly, and thereby enhance the performance of the canister. SOLUTION: Evaporated fuel from a gasoline tank enters into an evaporated fuel introduction chamber 5 through an evaporated fuel introducing port 2, and is changed in direction horizontally by a baffle plate 15 so as to be spreaded within the introduction chamber 5, and evaporated fuel is uniformly absorbed in the inside of a layer composed of absorbent 12. At the time of purging, atmosphere enters into an atmosphere port 3, and evaporated fuel absorbed in an absorbing layer is thereby purged through a purging port 4. And a space 16 contributes much toward uniform purging operations.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an evaporative fuel processing apparatus, and more specifically, it temporarily adsorbs and collects evaporative fuel generated in a gasoline tank of an automobile or the like, and the evaporative fuel is discharged to the atmosphere. The present invention relates to a processing device that prevents the occurrence of heat.

[0002]

2. Description of the Related Art Generally, an engine such as an automobile has a built-in adsorbent such as activated carbon so that evaporated fuel from a fuel tank or a float chamber of a carburetor is not discharged into the atmosphere to cause air pollution. A canister is provided so that the evaporated fuel is adsorbed and collected by the adsorbent when the engine is stopped, and the adsorbed evaporated fuel is purged into the engine by the intake air flow and burned while the engine is operating.

FIG. 3 shows a known evaporative fuel processing device of this type in Japanese Utility Model Laid-Open No. 57-123953.
In the figure, reference numeral 301 denotes a canister having a cylindrical side wall, which contains an adsorbent 302 therein. Reference numeral 304 denotes an evaporated fuel inlet port communicating with an upper air chamber of a fuel tank (not shown). In the adsorbent 302 layer, an obstruction made of a non-circular disc facing the lower opening end of the evaporated fuel inlet port 304. The plate 303 is arranged horizontally. Reference numeral 305 is a purge port communicating with an intake pipe of an engine (not shown), and reference numeral 306 is an atmosphere introduction port (atmosphere port) opening to the atmosphere.

The vaporized fuel from the upper air chamber of the fuel tank is introduced into the adsorbent 302 layer of the canister 301 through the vaporized fuel inlet 304, and the flow of the vaporized fuel is disturbed by the baffle plate 3.
It is turned to the side by 03.

[0005]

By the way, in the case where the fuel tank of the automobile is of a sealed type, for example, in the case where the fuel tank is refueled in a state in which the refueling port is sealed from the atmosphere, the upper part of the fuel tank is refueled. The evaporated fuel from the air chamber is rapidly pushed out toward the canister, and is introduced into the canister through the evaporated fuel inlet at a high speed.

In such a case, in the above-mentioned conventional technique, the vaporized fuel flowing at a high speed through the vaporized fuel inlet 304 is a disc-shaped non-perforated baffle plate 30 orthogonal to the flow direction.
When it is deflected at 3, a part of it hits the baffle plate 303 and is bounced back to the opposite direction, that is, toward the inlet 304 side, and a blind spot portion is generated at the lower part of the baffle plate 303, and The first problem is that the amount of adsorption becomes extremely small and a large adsorption difference occurs between the respective parts of the adsorbent 302 layer, resulting in poor adsorption efficiency during refueling.

Further, during refueling, a part of the fuel vapor that hits the baffle plate 303 at high speed is liquefied and falls off from the peripheral edge of the baffle plate 303, which is disadvantageous in that it is adsorbed uniformly. There was a problem.

Furthermore, when purging the adsorbed fuel vapor, the baffle plate 303 acts as a resistance and the adsorbent 302
The layer of adsorbed fuel is not evenly purged. That is, there is a third problem that the evaporated fuel adsorbed by the adsorbent 302 directly below the baffle plate 303 is not purged.

As described above, in the above-mentioned conventional technique, the device has been devised to improve the adsorption capability of the canister to improve its performance. However, on the contrary, the third problem that the purging capability is deteriorated occurs, so that after all. , The performance of the canister has not been improved so much.

Therefore, an object of the present invention is to provide an evaporative fuel treatment apparatus which can improve the performance of a canister and solve the above problems by increasing the adsorption capacity without lowering the purging capacity.

[0011]

In order to achieve the above object, the fuel vapor treatment system according to claim 1 has a fuel vapor introduction chamber (5) above the adsorbent (12) layer, and the fuel vapor introduction chamber (5) is provided. (5)
In the canister (1) with the evaporative fuel introduction port (2) opened, a baffle plate (15) is disposed in the introduction chamber (5) facing the evaporative fuel introduction port (2), and the baffle plate (15) is provided. ) Is smaller than the inner circumference of the introduction chamber (5), and a space (1) is provided between the baffle plate (15) and the adsorbent (12).
6) is provided.

The invention according to claim 2 is the evaporative fuel processing apparatus according to claim 1, wherein a plate-shaped bottom portion (15a) is horizontally arranged on the baffle plate (15) so as to face the evaporative fuel introduction port (2). ) And a peripheral wall (15b) rising from the peripheral edge of the bottom portion are formed.

The invention of claim 3 relates to claim 1 or 2.
In the vaporized fuel processing device of No. 3, a plurality of vent holes (15d) are opened at circumferentially spaced intervals in the radial middle portion of the bottom portion (15a) of the baffle plate (15).

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a preferred embodiment of the present invention, in which 1 is a canister as an evaporated fuel processing apparatus of the present invention, which has a cylindrical side wall case. Reference numeral 2 denotes an evaporated fuel introduction port which communicates with a vapor phase portion (not shown) such as a fuel tank via an evaporated fuel passage, and corresponds to the evaporated fuel inflow passage of the above-mentioned conventional technique.

Reference numeral 3 is an atmospheric port, and 4 is a purge port, which communicates with an intake passage of an engine (not shown) through an evaporated fuel discharge passage. 5 is a vaporized fuel introduction chamber and a canister 1
It is provided on the upper part. Reference numeral 6 denotes an atmosphere introducing chamber, which is formed below the canister 1. An adsorbent filling chamber 7 is formed between the two introducing chambers 5 and 6. A plate-shaped punching plate 8 having a large number of small holes formed above and below the filling chamber 7.
And 9 and filters 10 and 11 are provided so that the adsorbent 12 of activated carbon filled in the filling chamber 7 does not flow out into the chambers 5 and 6.

Reference numeral 13 is a spring provided between the punching plate 9 and the bottom surface of the canister 1. The evaporated fuel introducing port 2 is provided on the upper wall of the canister 1, and an evaporated fuel inflow pipe 14 opening to the evaporated fuel introducing chamber 5 is attached to the lower end of the canister 1.

Reference numeral 15 is a shallow cup-shaped baffle, and a flat disc-shaped bottom portion 15a is integrally formed with a cross-shaped projecting portion 15c when viewed from above, at the center thereof. Each of the radial ends 15c is provided with the vaporized fuel inflow pipe 14
The baffle plate 15 is attached to the evaporated fuel inflow pipe 14 by being fixed to the inner circumference of the lower part of the.

Reference numeral 15b is a peripheral wall which stands up at the peripheral edge of the bottom portion 15a of the baffle plate 15 and is formed in a shallow (short in the vertical direction) cylindrical shape.
It is formed integrally with the bottom portion 15a. The baffle 15
Has a bottom portion 15a at the inflow pipe 1 of the evaporated fuel introduction port 2.
4 is arranged so as to be positioned on a horizontal plane perpendicular to the vertical axis in the figure, and a space 16 is provided between the baffle plate 15 and the adsorbent 12 layer. The space 16 constitutes a part of the fuel vapor introduction chamber 5.

When refueling a fuel tank of an automobile, the evaporated fuel from the gas phase portion of the fuel tank passes through the inflow pipe 14 at a high speed, hits the bottom portion 15a, and is deflected in the radial direction to flow. Adsorbent 1 diffuses uniformly in the space of introduction chamber 5
It enters into two layers and is adsorbed and collected.

The peripheral wall 15b prevents the vaporized fuel from falling down from the baffle plate 15, so that the vaporized fuel is evenly adsorbed in the adsorbent 12 layer. Further, when the engine is in operation, negative pressure in the intake pipe is applied to the purge port 4, the atmosphere is introduced into the canister from the atmosphere port 3, and the evaporated fuel adsorbed by the adsorbent 12 is purged. 1
5 and the space 16 provided between the adsorbent 12 layers act effectively to purge the adsorbent 12 layer evenly.

[0021]

The embodiment of FIG. 2 is different from the embodiment of FIG. 1 in that the shape of the baffle plate 15 is slightly different, and the baffle plate 15 has a larger diameter than that of the embodiment of FIG. Further, the bottom portion 15a is provided with eight small vent holes 15d at equal intervals in the circumferential direction.

In this embodiment, the diameter of the baffle plate 15 is increased so that the vaporized fuel reaches the vicinity of the side wall (peripheral wall) of the vaporized fuel introducing chamber 5, and the vaporized fuel directly enters the space 16 from the ventilation hole 15d. As a result, the vaporized fuel was uniformly adsorbed and collected in the 12 layers of the adsorbent.

On the contrary, when purging, the purging is performed evenly.

[0024]

Since the evaporative fuel treatment apparatus of the present invention is configured as described above, the evaporative fuel can be evenly adsorbed by the adsorbent layer, and the adsorbed evaporative fuel can be evenly purged. The adsorption capacity and the purge capacity can both be improved, which helps improve the performance of the canister.

According to the second aspect of the invention, after the evaporated fuel is introduced into the introduction chamber (5), the fuel is prevented from dripping from the peripheral edge of the baffle plate (15), and the adsorbent is locally absorbed. All the deterioration.

Further, according to the third aspect of the present invention, even if the canister has a large diameter, the adsorption purge can be performed evenly.

[Brief description of the drawings]

FIG. 1 is a preferred embodiment of the present invention, in which (a) is a longitudinal sectional view and (b) is a view taken along line AA of (a).

FIG. 2 is an embodiment of the present invention, (a) is a longitudinal sectional view, (b)
FIG. 7B is a view taken along line BB of FIG.

FIG. 3 is a vertical sectional view of a conventional technique.

[Explanation of symbols]

 1 Canister 2 Evaporative Fuel Introducing Port 3 Atmosphere Port 4 Purge Port 5 Evaporative Fuel Introducing Chamber 7 Adsorbent Filling Chamber 12 Adsorbent 14 Inflow Pipe 15 Baffle Plate 15a Bottom 15b Circular Wall 15d Vent Hole

Claims (3)

[Claims] 1. A canister having an evaporated fuel introduction chamber above an adsorbent layer and having an evaporated fuel introduction port opened in the introduction chamber, wherein a baffle plate is provided in the introduction chamber facing the evaporated fuel introduction port. The vaporized fuel processing device is characterized in that the diameter of the baffle plate is set smaller than the inner circumference of the introduction chamber, and a space is provided between the baffle plate and the adsorbent layer. 2. The evaporative fuel treatment apparatus according to claim 1, wherein the baffle plate is provided with a plate-shaped bottom portion that is horizontally disposed so as to face the evaporative fuel introduction port, and a peripheral wall that rises from a peripheral edge of the bottom portion. . 3. The evaporated fuel processing apparatus according to claim 1, wherein a plurality of vent holes are provided at circumferentially spaced intervals in a radial middle portion of the bottom portion of the baffle plate.