JP3240091B2 - Evaporative fuel processing equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a first and second adsorbent-filled layers, each of which is filled with an adsorbent for adsorbing evaporated fuel, in a cylindrical casing having both ends closed. A first chamber formed between one end surface of the first adsorbent-filled layer and one end wall of the casing is provided, with a partition wall fixed to the one end wall interposed therebetween. An evaporative fuel passage for introducing evaporative fuel from the fuel cell and a purge gas passage for introducing purge gas to an intake system of the engine are connected to each other, and a second chamber formed between the second adsorbent packed layer and one end wall of the casing is connected to the atmosphere. And a third chamber common to both the adsorbent-filled layers is formed between the first and second adsorbent-filled layers and the other end wall of the casing.

[0002]

2. Description of the Related Art Conventionally, such an apparatus is disclosed in, for example,
It is already known, for example, from Japanese Patent Application No. 159455.

[0003]

SUMMARY OF THE INVENTION In the above prior art,
When the axial length of the casing is L and the diameter is D by flowing the fuel vapor from the fuel tank in series from the first chamber to the second adsorbent packed layer through the first adsorbent packed bed and the third chamber. Therefore, L / D is increased without increasing L.

However, the generation of fuel vapor from the fuel tank is slow when the vehicle is parked or stopped, and the flow rate of the fuel vapor is relatively small. Therefore, it is necessary to sufficiently supply the fuel vapor to the first and second adsorbent packed beds. However, at the time of refueling, a relatively large amount of evaporative fuel is generated in the fuel tank, so that the flow rate of the evaporative fuel is also relatively large. Has a relatively large ventilation resistance, which may result in insufficient supply of evaporated fuel to both intake agent-filled layers and insufficient supply of fuel into the fuel tank. There was a problem that we had to do.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and it has been proposed to reduce the flow resistance of evaporative fuel generated in a fuel tank at the time of refueling in an adsorbent-filled layer to a relatively low level. It is an object of the present invention to provide an evaporative fuel treatment apparatus capable of supplying sufficient fuel to a fuel tank and enabling sufficient fuel supply to a fuel tank.

[0006]

In order to achieve the above object, according to the first aspect of the present invention, an adsorbent for adsorbing evaporated fuel is filled in a cylindrical casing whose both ends are closed. The first and second adsorbent-filled layers are provided with a partition wall fixed to one end wall of the casing interposed therebetween, and are provided between one end face of the first adsorbent-filled layer and one end wall of the casing. The first chamber formed is connected to an evaporative fuel passage for guiding evaporative fuel from the fuel tank at the time of refueling, and a purge gas passage for guiding purge gas to an intake system of the engine. A second chamber formed between the first end wall and the other end wall of the casing is provided between the first and second adsorbent packed layers and the other end wall of the casing. In the evaporative fuel processing device to be formed, the third chamber is set to the atmosphere. Switching control valve means capable of at least switching between a first switching state in which the third chamber is opened but cut off from the fuel vapor passage and a second switching state in which the third chamber is cut off from the atmosphere but communicates with the fuel vapor passage is provided. It is characterized by the following.

[0007] The invention according to claim 2 provides the above-described claim 1.
In addition to the configuration of the invention described in the above, a detector for detecting that the adsorption of the evaporated fuel in the first adsorbent packed bed is almost completed, and the detector is a first adsorbent packed bed when the fuel is supplied to the fuel tank. The first switching state is set until it is detected that the adsorption of the evaporated fuel is almost completed, but after the detector detects that the adsorption of the evaporated fuel in the first adsorbent packed layer is almost completed, the first switching state is reached. And control means for controlling the switching operation of the switching control valve means so as to set the switching state to 2.

[0008]

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

FIGS. 1 to 3 show a first embodiment of the present invention. FIG. 1 is a diagram showing the configuration of an evaporative fuel processing apparatus in an operating state in the first half of refueling, and FIG. FIG. 3 is a diagram illustrating a change in the temperature of the adsorbent, and FIG. 3 is a diagram illustrating a configuration of the evaporated fuel processing apparatus in an operating state in the latter half of refueling.

First, in FIG. 1, one end of a first evaporative fuel passage 1 in which a two-way valve 3 is interposed is connected to an upper space in a fuel tank T mounted on a vehicle. Is connected to the upper part of the canister C. One end of the second evaporative fuel passage 2 is connected to the upper space of the fuel tank T, and the other end of the second evaporative fuel passage 2 is also connected to the upper part of the canister C. In addition, an electromagnetic opening / closing valve 4 that is opened at the time of refueling is provided at an intermediate portion of the second evaporated fuel passage 2. Further, one end of a purge gas passage 5 having a purge gas control valve 6 is connected to an upper portion of the canister C. The other end of the purge gas passage 5 is connected to a throttle valve 8 in an intake system 7 of an engine E mounted on a vehicle. Is also connected to the downstream side.

The two-way valve 3 opens when the internal pressure of the fuel tank T rises above a predetermined value above the atmospheric pressure, and when the internal pressure of the fuel tank T exceeds a predetermined value above the internal pressure of the canister C. When the pressure drops, the valve is opened to allow communication between the fuel tank T and the canister C. When the purge gas from the canister C is purged into the intake system 7, the pressure on the canister C side may become negative. In this case, the two-way valve 3 is kept closed.

The canister C has a cylindrical casing 10 whose both ends in the axial direction are closed by first and second end walls 11 and 12, respectively. The casing 10 is mounted on a vehicle with the axis vertical. . This casing 10
A partition wall 13 extending toward the second end wall 12, ie, the lower end wall, is fixed to the first end wall 11, that is, the upper end wall. At a position slightly inward in the axial direction from the first end wall 11, a peripheral portion of the mesh member 21 that allows the passage of the fuel vapor is fixedly supported on the inner surface of the casing 10 and one side surface of the partition wall 13. The casing 10 is positioned at a position corresponding to the mesh member 21.
The inner peripheral surface of the partition member 13 and the other side surface of the partition member 13 are fixedly supported by a peripheral portion of a mesh member 22 that allows the passage of fuel vapor.
On the inner surface of the casing 10 at the front end of the partition wall 13, that is, between the lower end and the second end wall 12, a peripheral portion of a mesh member 23 that allows the passage of the evaporated fuel is fixedly supported. Thus, an adsorbent for adsorbing the evaporated fuel, such as activated carbon, is filled between the mesh members 21 and 23 on one side of the partition wall 13 to form the first adsorbent packed layer 14, and the mesh member is formed on the other side of the partition wall 13. The second adsorbent-filled layer 15 is formed by filling the adsorbent between 22 and 23. Further, a first chamber 16 is provided between one end surface of the first adsorbent packed layer 14 and the first end wall 11 of the casing 10.
Is formed, and a second chamber 17 is formed between the second adsorbent-filled layer 15 and the first end wall 11 of the casing 10, and the other end faces of the first and second adsorbent-filled layers 14, 15 and the casing 10 between the second end wall 12 and both adsorbent packed layers 14,
A third chamber 18 is formed so that the other end surfaces of the third chamber 15 face in common.

The first end wall 11 of the casing 10 has a first
The purge gas passage 5 is connected to the first chamber 16 and the second chamber 17 is open to the atmosphere.

The second end wall 12 of the casing 10 has
One end of the open path 24 corresponds to a position below the first adsorbent packed layer 14.
And one end of the auxiliary evaporative fuel passage 25
Are connected correspondingly below the second adsorbent packed layer 15 and open.
The other end of the discharge passage 24 is open to the atmosphere, and the auxiliary evaporative fuel passage 2
The other end of 5 is located downstream of the solenoid on-off valve 4 and has a second vaporized fuel passage.
It is connected to Road 2. In addition, electromagnetic open / close switching on the open path 24
A valve 26 is provided.
Switching control valve means 20 together with magnetic switching valve 26 ₁Configure
An electromagnetic open / close switching valve 27 is provided.

[0015] Thus by switching control valve means 20 _1, the third chamber 18 to be opened to the atmosphere, but the second evaporative fuel path to close the solenoid on-off switching valve 27 while opening the electromagnetic on-off changeover valve 26 2 And the electromagnetic switching valve 27
And the electromagnetic open / close switching valve 26 is closed to open the third
A second switching state in which the chamber 18 is cut off from the atmosphere but communicates with the second evaporative fuel passage 2;
Can be switched to a third switching state in which the third chamber 18 is shut off from the atmosphere and the second evaporative fuel passage 2 is shut off.

The electromagnetic valve 4, the opening and closing operation of the purge gas control valve 6 and the switching control valve means 20 ₁ is intended to be controlled by the electronic control unit ECU as a control unit,
The electronic control unit ECU, the temperature detector S ₁ for detecting that the adsorption of the fuel vapor in the first adsorbent filling layer 14 is almost completed, it is performed refueling the fuel tank T by fueling gun G Is connected to a refueling detector 29 attached to the refueling pipe 28 in order to detect the presence of the fuel.

The temperature detector S ₁ is inserted into a portion of the first adsorbent packed bed 14 near the third chamber 18, and detects the temperature of the fuel adsorbed by the first adsorbent packed bed 14. Based on the temperature change according to the progress, it is detected that the adsorption of the evaporated fuel in the first adsorbent packed bed 14 is almost completed. That is, when the adsorption of the fuel vapor with an adsorbent such as activated carbon, as shown in Figure 2, the temperature is from the time t _o at which the adsorption is nearly completed, but the fuel vapor temperature of the adsorbent rises from the beginning adsorption of fuel vapor is intended to decrease, the first adsorbent filling layer 14 by detecting the time of maximum temperature at a temperature detector S ₁
Can be detected that the adsorption is almost completed.

Next, the operation of the first embodiment will be described. When refueling the fuel tank T with the refueling gun G,
Purge control valve 6 is set to the closed state with the solenoid valve 4 is an open state, the switching control valve means 20 _1, the electromagnetic on-off switching valve 2 while opening the electromagnetic on-off changeover valve 26
7 is closed to open the third chamber 18 to the atmosphere, but to the first switching state in which the third chamber 18 is disconnected from the second evaporated fuel passage 2.

In this state, the evaporated fuel generated in the fuel tank T is introduced into the first chamber 16 of the canister C, and passes through the first adsorbent-filled layer 14 as shown by an arrow.
Adsorbed by the adsorbent. Thus, most of the gas after flowing through the first adsorbent packed layer 14 is supplied from the third chamber 18 to the open channel 24.
And a part of the gas flows from the first adsorbent filled layer 14 to the second adsorbent filled device 15 side.

[0020] When the temperature detector S ₁ is the adsorption of the fuel vapor in the first adsorbent filling layer 14 has been substantially completed is detected then that switching control valve means 20 _1, as shown in Figure 3, the electromagnetic The third opening / closing switching valve 26 is closed and the electromagnetic opening / closing switching valve 27 is opened to shut off the third chamber 18 from the atmosphere. However, the second switching state is established in which the third chamber 18 communicates with the second evaporated fuel passage 2. At this time, the opening / closing operation of the electromagnetic opening / closing switching valve 27 is performed prior to the closing operation of the electromagnetic opening / closing switching valve 26. Is operated to close the valve.

As a result, the fuel vapor from the fuel tank T is introduced from the second fuel vapor passage 2 into the third chamber 18 via the auxiliary fuel vapor passage 25. Thus, before the evaporated fuel introduced into the third chamber 18 is discharged from the open passage 24 to the outside with the opening operation of the electromagnetic opening / closing switching valve 27, the closing operation of the electromagnetic opening / closing switching valve 26 is executed. The predetermined time set between the valve opening timing of the electromagnetic switching valve 27 and the valve closing timing of the electromagnetic switching valve 26 is set to be extremely short.

Most of the evaporated fuel that has flowed into the third chamber 18 flows upward through the second adsorbent packed layer 15 because the second chamber 17 is open to the atmosphere. It will be adsorbed by the adsorbent in the packed bed 15. At this time, a part of the evaporated fuel may flow to the first adsorbent packed layer 14 side.

As described above, most of the evaporated fuel flows through the first adsorbent packed layer 14 until the adsorption in the first adsorbent packed bed 14 is almost completed, After the adsorption is almost completed, most of the evaporated fuel flows through the second adsorbent packed layer 15, so that a relatively large amount of evaporated fuel is generated in the fuel tank T when the fuel is supplied to the fuel tank T. However, it is possible to prevent the ventilation resistance in the canister C from becoming larger than the allowable value. For example, when the permissible airflow resistance in the canister C is 100 mmAq, the L / D of the casing 10 is set so that the airflow resistance in each of the first intake agent filling layer 14 and the second intake agent filling layer 15 becomes 100 mmAq. Is possible.
That is, the L / D of the canister C can be made larger than before, and the utilization rate of the canister C during refueling can be increased.

The parking of the vehicle, when the vehicle is stopped, the shut-off with the solenoid valve 4 is closed, the switching control valve means 20 ₁ is the third chamber 18 by both closed both electromagnetic switching selector valve 26 from the atmosphere At the same time, a third switching state is established in which the second evaporated fuel passage 2 is also shut off. As a result, the fuel vapor from the fuel tank T is introduced into the first chamber 16 of the canister C via the two-way valve 3, and the first adsorbent packed bed 14, the third chamber 18, and the second chamber 18 are formed at a relatively slow flow speed. It flows so as to reach the second chamber 17 via the two adsorbent filled layers 15, and the HC component is adsorbed in the same manner as in the conventional canister. Therefore, L / D can be made sufficiently large as in the prior art, and the migration of HC components can be prevented, so that the fuel vapor can be sufficiently adsorbed.

FIG. 4 shows a second embodiment of the present invention, in which parts corresponding to those of the first embodiment are denoted by the same reference numerals.

The second end wall 12 of the casing 10 has a passage 3
The third chamber 18 is opened to the atmosphere between the passage 30 and the auxiliary evaporative fuel passage 25 ′ connected to the second evaporative fuel passage 2 and the atmosphere.
A second switching state in which the third chamber 18 is cut off from the atmosphere but communicates with the second evaporative fuel passage 2; a second switching state in which the third chamber 18 is cut off from the atmosphere; 3-port 3-position electromagnetic switching valve 2 as switching control valve means capable of switching between a third switching state in which the evaporative fuel passage 2 is also shut off
0 ₂ is provided.

The casing 10 is provided with H in the third chamber 18.
Determining HC detector S ₂ that breakthrough began in the first adsorbent filling layer 14 adsorbing in the first adsorbent filling layer 14 is substantially completed is attached by detecting the C concentration.

According to the second embodiment, the HC detector S
3 by the electronic control unit ECU according to the detection signal of _2.
By switching control the operation of the port three-position electromagnetic switching valve 20 _2, it is possible to obtain the same effect as in the first embodiment.

Although the embodiments of the present invention have been described in detail, the present invention is not limited to the above embodiments, and various design changes can be made without departing from the present invention described in the appended claims. It is possible to do.

For example, in the second evaporative fuel passage 2, an on-off valve may be provided between the branch portion of the auxiliary evaporative fuel passages 25 and 25 'and the first chamber 16 of the canister C. A timer that measures the time from the start of refueling to the elapse of a set time may be used as a detector that detects that the adsorption of the evaporated fuel in the packed bed 14 is almost completed. Further, the present invention can be applied to an evaporative fuel processing device dedicated to refueling in which the evaporated fuel from the fuel tank T is adsorbed only during refueling.

[0031]

As described above, according to the first aspect of the present invention, the first and second cylinders each having a tubular casing closed at both ends are filled with an adsorbent for adsorbing fuel vapor.
A first chamber formed between the one end surface of the first adsorbent packed layer and one end wall of the casing, the adsorbent packed layer being provided with a partition wall fixed to one end wall of the casing interposed therebetween; Is connected to an evaporative fuel passage for introducing evaporative fuel from the fuel tank at the time of refueling, and a purge gas passage for introducing purge gas to the intake system of the engine, and is provided between the second adsorbent packed layer and one end wall of the casing. The second chamber formed is open to the atmosphere, and a third chamber common to both the adsorbent-filled layers is formed between the first and second adsorbent-filled layers and the other end wall of the casing. In the apparatus, at least a first switching state in which the third chamber is opened to the atmosphere but cut off from the evaporative fuel passage, and a second switching state in which the third chamber is cut off from the atmosphere but communicated with the evaporative fuel passage are at least performed. Since switching control valve means is provided for switching, By switching the second adsorbent packed layer to adsorb the evaporated fuel, the airflow resistance of the evaporated fuel in the adsorbent packed bed is kept relatively low so that the evaporated fuel can be sufficiently fed to both adsorbent packed beds. As a result, sufficient fuel supply to the fuel tank becomes possible.

The second aspect of the present invention is directed to the first aspect.
In addition to the configuration of the invention described in the above, a detector for detecting that the adsorption of the evaporated fuel in the first adsorbent packed bed is almost completed, and the detector is a first adsorbent packed bed when the fuel is supplied to the fuel tank. The first switching state is set until it is detected that the adsorption of the evaporated fuel is almost completed, but after the detector detects that the adsorption of the evaporated fuel in the first adsorbent packed layer is almost completed, the first switching state is reached. And control means for controlling the switching operation of the switching control valve means so as to set the first and second switching states.
By appropriately controlling the switching timing of the adsorbent packed layer, more effective adsorption becomes possible.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of an evaporative fuel processing device in an operating state in a first half of refueling time of a first embodiment.

FIG. 2 is a diagram showing a change in adsorbent temperature over time.

FIG. 3 is a diagram illustrating a configuration of an evaporative fuel processing apparatus in an operating state in a latter half of refueling.

FIG. 4 is a diagram illustrating a configuration of an evaporative fuel processing apparatus according to a second embodiment.

[Explanation of symbols]

2 ... Evaporated fuel passage 5 ... Purge gas passage 7 ... Intake system 10 ... Casing 11, 12 ... End wall 13 ... Partition wall 14 ... First adsorbent packed bed 15 ... ..The second adsorbent packed layer 16: the first chamber 17 ... the second chamber 18 ... the third chamber 20 ₁ ... the switching control valve means 20 ₂ ... 3 as the switching control valve means the electronic control unit S ₁ · · · temperature detector S ₂ · · · HC detector T · · · fuel tank as a port three-position electromagnetic switching valve E · · · engine ECU · · · control means

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Teruo Wakagi 1-4-1 Chuo, Wako-shi, Saitama Pref. Inside of Honda R & D Co., Ltd. (72) Inventor Tomoyuki Kawakami 143 Hagadai, Haga-cho, Haga-gun Tochigi Pref. (56) References JP-A-1-159455 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) F02M 25/08 F02M 25/08 311

Claims (2)

(57) [Claims] A tubular casing (1) having both ends closed.
First and second adsorbent packed layers (14, 15), each of which is filled with an adsorbent for adsorbing fuel vapor.
Are provided with a partition wall (13) fixed to one end wall (11) of the casing (10) interposed therebetween, and one end face of the first adsorbent packed layer (14) and one end of the casing (10) are provided. A first chamber (16) formed between the first chamber (16) and the wall (11) has an evaporative fuel passage (2) for introducing evaporative fuel from the fuel tank (T) at the time of refueling, and purge gas for intake of the engine (E). A purge gas passage (5) leading to the system (7) is connected;
A second chamber (17) formed between the second adsorbent-filled layer (15) and one end wall (11) of the casing (10) is opened to the atmosphere, and the first and second adsorbent-filled layers (14) are opened. , 15)
In the evaporative fuel treatment apparatus, a third chamber (18) common to both the adsorbent-filled layers (14, 15) is formed between the second chamber (18) and the other end wall (12) of the casing (10). 18) is opened to the atmosphere but is cut off from the fuel vapor passage (2).
Switching control valve means (20 ₁ , 20 ₂ ) capable of at least switching between the switching state of (1) and the second switching state of shutting off the third chamber (18) from the atmosphere but communicating with the evaporated fuel passage (2). An evaporative fuel treatment device comprising: 2. Detectors (S ₁ , S ₁ ) for detecting that the adsorption of the evaporated fuel in the first adsorbent packed bed (14) is almost completed.
₂ ) and the detector (S) when refueling the fuel tank (T).
₁ , S ₂ ) is in the first switching state until it is detected that the adsorption of the evaporated fuel in the first adsorbent packed bed (14) is almost completed, but the first adsorbent packed bed (14) does not. After the detectors (S ₁ , S ₂ ) detect that the adsorption of the evaporated fuel is almost completed, the switching operation of the switching control valve means (20 ₁ , 20 ₂ ) is performed by setting the second switching state. The evaporative fuel processing apparatus according to claim 1, further comprising control means (ECU) for controlling.