JPH0674107A - Evaporation fuel treatment device - Google Patents

Abstract

PURPOSE:To prevent evaporation fuel adsorbed on a main canister from dispersing on an auxiliary canister so as to flow out in the atmosphere, from the atmospheric port of the auxiliary canister. CONSTITUTION:Gasoline vapor generated in the upper part gas chamber 1a of a fuel tank 1 is adsorbed on adsorbent 3 of the main canister 4 through an evaporation fuel passage 2. Evaporation fuel adsorbed on the adsorbent 3 is dispersed to the adsorbent 8 of the auxiliary canister 7, and the flow amount thereof is restricted by a throttle 10 so as to prevent evaporation fuel from flowing out from an atmospheric port 9 into the atmosphere.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automobile fuel vapor treatment system.

[0002]

2. Description of the Related Art In automobiles, an evaporated fuel processing device is used to prevent gasoline vapor from flowing into the atmosphere.

FIG. 4 shows the conventional technique. Reference numeral 1 is a fuel tank, 2 is an evaporative fuel passage, one end of which opens to the upper air chamber of the fuel tank 1 and the other end communicates with a tank port 4a of a main canister 4 filled with an adsorbent 3, and 5 a main canister 4 Is a purge line having one end connected to the purge port 4b and the other end connected to a negative pressure port 6 of an intake pipe of an engine (not shown).

A sub-canister 7 is connected in series with the main canister 4. 8 is an adsorbent filled in the sub-canister 7, and 9 is an atmospheric port on the downstream side of the sub-canister 7.

As described above, by arranging the main and sub canisters in series, a canister having a large capacity as a whole and a space-saving method is disclosed in Japanese Utility Model Laid-Open No. 61-25568. It is described in FIG.

[0006]

SUMMARY OF THE INVENTION In the above conventional technique,
When the temperature of the vehicle rises during the day and the gasoline in the tank 1 evaporates when the vehicle is left for a long time, the evaporated gasoline vapor is adsorbed by the adsorbent 3 of the main canister 4 via the vaporized fuel passage 2. .

[0007] At night, when the temperature drops, the generation of gasoline vapor decreases, but the adsorbent 3 of the main canister 4
The vaporized fuel adsorbed on is diffused and adsorbed on the adsorbent 8 of the sub-canister 7. When the temperature drops, the pressure in the tank drops, and air enters the tank from the atmospheric port 9 through the sub canister 7 and the main canister 4. Reference numeral 6 is a port of the intake passage.

When the engine is left for a long time, the vapor of the main canister diffuses and flows into the sub-canister, and a large amount of evaporated fuel is adsorbed by the adsorbent 8 of the sub-canister. When the temperature in the tank rises in this state, the pressure of the fuel vapor in the tank rises, and the air in the tank is released from the main canister through the sub canister to the atmosphere. Therefore, the vaporized fuel will be removed from the air port 9 along with the air.
There was a problem that it leaked out from and polluted the atmosphere.
Therefore, it is an object of the present invention to provide an evaporative fuel treatment device that can solve such problems.

[0009]

In order to achieve the above object, the evaporated fuel processing apparatus of the present invention comprises a main canister in an upper air chamber (1a) of a fuel tank (1) via an evaporated fuel passage (2). A configuration in which (4) and the sub-canister (7) are connected in series is characterized in that a diaphragm (10) is arranged between the main canister (4) and the sub-canister (7).

[0010]

When the evaporated fuel adsorbed by the main canister (4) tries to diffuse into the sub canister (7), the throttle (10) suppresses it.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the first embodiment of FIG. 1, 1 is a fuel tank, 2 is a vaporized fuel passage, one end of which opens into an upper air chamber 1a of the fuel tank 1 and the other end communicates with a tank port 4a of a main canister 4. is doing.

Reference numeral 3 is an adsorbent filled in the main canister 4 and reference numeral 4b is a purge port of the canister 4, which is connected to a port of the intake passage 12 via a purge line 5. Reference numeral 11 denotes a duty control valve inserted in the purge line 5, and its opening (duty ratio) is controlled by an ECU (electronic control unit) (not shown) according to operating conditions of the engine 15 to adjust the purge amount. To do.

Reference numeral 13 is a throttle valve, 14 is an air filter, and 15 is an engine. Reference numeral 7 is a sub-canister filled with an adsorbent 8, and a port 7a at the upper portion of the sub-canister is a throttle 10
Is connected to the lower port 4c of the main canister 4 via. Reference numeral 9 is an atmospheric port provided below the sub-canister 7.

The fuel vapor generated in the upper air chamber 1a of the fuel tank 1 passes through the evaporated fuel passage 2 and enters the canister 4 from the tank port 4a and is adsorbed by the adsorbent 3. When the concentration of the evaporated fuel adsorbed by the adsorbent 3 increases, the evaporated fuel diffuses into the canister 7 through the port 4c, the throttle 10 and the port 7a and is adsorbed by the adsorbent 8. At this time, the main canister The amount of evaporated fuel that moves from 4 to the sub-canister 7 is limited by the throttle 10.

During operation of the vehicle, the fuel adsorbed by both canisters 4, 7 is drawn into the intake passage 12 through the purge line 5 and burned by the engine 15. Since the resistance of the throttle 10 reduces the purge of the sub-canister 7 at this time,
It is better not to unnecessarily increase the flow resistance of the throttle 10, and it is better to ensure that the minimum area necessary for purging the canister is secured.

In the second embodiment of FIG. 2, the case of the main canister 4 and the sub-canister 7 has an integrated structure, and a diaphragm 10 is provided between the storage chambers for storing the adsorbents 3 and 8 of both. By integrating the case of the canister,
Space can be reduced. In the third embodiment shown in FIG. 3, the main canister 4 and the sub-canister 7 are vertically arranged in the reverse order of the second embodiment shown in FIG. Since the evaporated fuel generated from the tank has a property that a fuel component having a large specific gravity among them is accumulated below, according to the third embodiment, a large amount of evaporated fuel is adsorbed by the adsorbent 3 of the lower main canister 4. It is especially effective.

[0017]

Since the evaporated fuel processing apparatus of the present invention is configured as described above, it is possible to suppress the amount of evaporated fuel that diffuses from the main canister to the sub canister and prevent the evaporated fuel from flowing into the atmosphere. .

[Brief description of drawings]

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

FIG. 2 is a vertical sectional view of a canister used in a second embodiment of the present invention.

FIG. 3 is a vertical sectional view of a canister used in a third embodiment of the present invention.

FIG. 4 is a conventional system diagram.

[Explanation of symbols]

 1 Fuel Tank 1a Upper Air Chamber 2 Evaporative Fuel Passage 4 Main Canister 7 Sub Canister 10 Throttle

Claims (1)

[Claims] 1. A main canister and a sub-canister are connected in series to an upper air chamber of a fuel tank via an evaporative fuel passage, wherein a throttle is arranged between the main canister and the sub-canister. Evaporative fuel processor.