JPH0828366A - Evaporated fuel processor - Google Patents

Abstract

PURPOSE:To sufficiently send evaporated fuel into an adsorbent filling layer, and feed sufficient oil to a fuel tank by switching a condition where a third chamber is opened to the atmosphere but is cut off from an evaporated fuel passage and a condition where the third chamber is cut off from the atmosphere but is communicated with the evaporated fuel passage to/from each other. CONSTITUTION:At feed oil time, a solenoid opening-closing valve 4 opens, and a purge gas control valve 6 closes, and a switching control valve means 20 opens a directional control valve 26, and closes a directional control valve 27, and opens a third chamber 18 to the atmosphere, but cut off it from a second evaporated fuel passage 2. Evaporated fuel generated in a fuel tank T is introduced to a first chamber 16, and is adsorbed to a first adsorbent filling layer 14. When the fact that adsorption of the evaporated fuel in the first adsorbent filling layer 14 is almost completed is detected by a temperature detector S1, the switching control valve means 20 closes the directional control valve 26, and opens the directional control valve 27, and cut off the third chamber 18 from the atmosphere, but communicates it with the second evaporated fuel passage 2. The evaporated fuel is introduced to the third chamber 18 through an auxiliary evaporated fuel passage 25 from the second evaporated fuel passage 2, and is adsorbed to a second adsorbent filling layer 15.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a casing having first and second adsorbent-filled layers each filled with an adsorbent for adsorbing vaporized fuel in a cylindrical casing whose both ends are closed. A fuel tank at the time of refueling is provided in a first chamber, which is provided by sandwiching a partition wall fixed to one end wall between the one end face of the first adsorbent-filled layer and one end wall of the casing. The second chamber formed between the second adsorbent filling layer and the one end wall of the casing is connected to the atmosphere by connecting the evaporative fuel passage for guiding the evaporative fuel from the exhaust gas and the purge gas passage for discharging the purge gas to the intake system of the engine. The present invention relates to an evaporative fuel treatment apparatus in which a third chamber common to both adsorbent-filled beds is formed between the first and second adsorbent-filled beds and the other end wall of the casing.

[0002]

2. Description of the Related Art Conventionally, such a device is disclosed in, for example, Japanese Patent Laid-Open No.
It is already known from Japanese Patent Publication No. 159455.

[0003]

SUMMARY OF THE INVENTION In the above conventional one,
When the axial length of the casing is L and the diameter is D by flowing the evaporated fuel from the fuel tank in series from the first chamber to the second adsorbent-filled layer through the first adsorbent-filled layer and the third chamber In addition, L / D is increased without increasing L.

However, the generation of the evaporated fuel from the fuel tank is gentle when the vehicle is parked or stopped, and the flow velocity of the evaporated fuel is relatively small. Therefore, the evaporated fuel should be sufficiently sent to the first and second adsorbent packed beds. However, since a relatively large amount of vaporized fuel is generated in the fuel tank during refueling, the flow velocity of vaporized fuel is also relatively high, which causes the third chamber to be interposed between the two intake agent filled layers in series. Has a relatively large ventilation resistance, which may result in inadequate delivery of evaporated fuel to both intake agent-filled layers and inadequate refueling in the fuel tank. There was a problem that I had to do.

The present invention has been made in view of the above circumstances, and the ventilation resistance of the evaporative fuel generated in the fuel tank during refueling in the adsorbent-filled layer is suppressed to a relatively low level, and the vaporized fuel in the adsorbent-filled layer is suppressed. It is an object of the present invention to provide an evaporated fuel processing device capable of sufficiently supplying fuel to a fuel tank to allow sufficient fuel supply.

[0006]

In order to achieve the above object, the invention according to claim 1 is such that an adsorbent for adsorbing vaporized 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 sandwiched therebetween, and between the one end face of the first adsorbent-filled layer and the one end wall of the casing. An evaporative fuel passage that guides the evaporated fuel from the fuel tank at the time of refueling and a purge gas passage that guides the purge gas to the intake system of the engine are connected to the first chamber formed, and the second adsorbent filling layer and the casing are connected. The second chamber formed between the one end wall is opened to the atmosphere, and the third chamber common to both adsorbent filling devices is provided between the first and second adsorbent filling layers and the other end wall of the casing. In the evaporative fuel treatment system to be formed, the third chamber is placed in the atmosphere. A switching control valve means is provided which is capable of at least switching between a first switching state in which the evaporative fuel passage is opened but is shut off from the evaporative fuel passage, and a second switching state in which the third chamber is shut off from the atmosphere but communicates with the evaporative fuel passage. It is characterized by

The invention according to claim 2 is the above-mentioned claim 1.
In addition to the configuration of the invention described 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 the first adsorbent packed bed when refueling the fuel tank. The first switching state is maintained until it detects that the adsorption of the evaporated fuel is almost completed. However, after the detector detects that the adsorption of the evaporated fuel in the first adsorbent packed bed is almost completed, Control means for controlling the switching operation of the switching control valve means so as to be in the switching state of No. 2.

[0008]

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

1 to 3 show a first embodiment of the present invention, FIG. 1 is a diagram showing a structure of an evaporated fuel processing apparatus in an operating state in the first half of refueling, and FIG. FIG. 3 is a diagram showing a change in adsorbent temperature, and FIG. 3 is a diagram showing a configuration of the evaporated fuel processing device 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. The other end of is connected to the upper part of the canister C. Further, one end of the second evaporated fuel passage 2 is connected to the upper space of the fuel tank T, and the other end of the second evaporated fuel passage 2 is also connected to the upper part of the canister C. Moreover, an electromagnetic opening / closing valve 4 that is opened at the time of refueling is provided in the middle 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, and 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 the atmospheric pressure by a predetermined value, and the internal pressure of the fuel tank T exceeds the internal pressure of the canister C by a predetermined value. When the pressure drops, the valve is opened to allow communication between the fuel tank T and the canister C. Further, when the purge gas from the canister C is purged into the intake system 7, the canister C side may have a negative pressure. In that case, the two-way valve 3 is kept closed.

The canister C is provided with a cylindrical casing 10 whose both axial ends are closed by first and second end walls 11 and 12, respectively. The casing 10 is mounted on a vehicle with its axis being vertical. . This casing 10
A partition wall 13 extending toward the second end wall 12, that is, the lower end wall is fixed to the first end wall 11, that is, the upper end wall. Thus, at the position slightly inward of the first end wall 11 in the axial direction, the inner surface of the casing 10 and one side surface of the partition wall 13 are fixedly supported by the peripheral edge portion of the mesh member 21 that allows passage of the evaporated fuel. The casing 10 at a position corresponding to the mesh member 21.
The inner peripheral surface of the partition wall 13 and the other side surface of the partition wall 13 fixedly support the peripheral edge portion of the mesh member 22 that allows passage of the evaporated fuel.
A peripheral portion of a mesh member 23 that allows passage of evaporated fuel is fixedly supported on the inner surface of the casing 10 at an intermediate portion between the front end, that is, the lower end of the partition wall 13 and the second end wall 12. Thus, on one side of the partition wall 13, the first adsorbent-packed layer 14 is formed by filling an adsorbent such as activated carbon that adsorbs the evaporated fuel between the net members 21 and 23, and on the other side of the partition wall 13. The second adsorbent filling layer 15 is formed by filling the adsorbent between 22 and 23. In addition, the first chamber 16 is provided between the one end surface of the first adsorbent filling layer 14 and the first end wall 11 of the casing 10.
Is formed, 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 surfaces of the first and second adsorbent-filled layers 14 and 15 and the casing are formed. Between the second end wall 12 of 10, both adsorbent packed layers 14,
A third chamber 18 is formed so that the other end surface of 15 is faced in common.

The first end wall 11 of the casing 10 has a first
The second evaporated fuel passages 1 and 2 are connected to each other and the purge gas passage 5 is connected to the first chamber 16 so that the second chamber 17 is opened to the atmosphere.

The second end wall 12 of the casing 10 has
One end of the open path 24 corresponds to below the first adsorbent packed bed 14.
One end of the auxiliary vaporized fuel passage 25
Is connected correspondingly to the lower side of the second adsorbent filling layer 15, and is opened.
The other end of the discharge passage 24 is opened to the atmosphere, and the auxiliary vaporized fuel passage 2
The other end of 5 is on the downstream side of the electromagnetic on-off valve 4 and the second evaporative fuel passage
Connected to path 2. Moreover, the open / closed path 24 is electromagnetically switched.
A valve 26 is provided, and the auxiliary vaporized fuel passage 25 has
Switching control valve means 20 together with magnetic switching valve 26 ₁Make up
An electromagnetic opening / closing switching valve 27 is installed.

Thus, the switching control valve means 20 ₁ opens the electromagnetic switching valve 26 and closes the electromagnetic switching valve 27 to open the third chamber 18 to the atmosphere, but the second evaporated fuel passage 2 And a first switching state for shutting off the
To open the solenoid open / close switching valve 26 and close the third
A second switching state in which the chamber 18 is shut off from the atmosphere but communicates with the second evaporated fuel passage 2, and both electromagnetic opening / closing switching valves 26, 27.
Can be switched to a third switching state in which the third chamber 18 is shut off from the atmosphere and the second evaporated 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 is provided with a temperature detector S ₁ for detecting that the adsorption of the evaporated fuel in the first adsorbent filling layer 14 is almost completed, and the fuel tank T is refueled with a refueling gun G. An oil supply detector 29 attached to the oil supply pipe 28 is connected to detect that the oil supply is present.

The temperature detector S ₁ is inserted into the portion of the first adsorbent-packed layer 14 near the third chamber 18, and the adsorption of the evaporated fuel in the first adsorbent-packed layer 14 is performed. It is detected that the adsorption of the vaporized fuel in the first adsorbent packed bed 14 is almost completed by the temperature change according to the progress. That is, when adsorbing the evaporated fuel with the adsorbent such as activated carbon, as shown in FIG. 2, the temperature of the adsorbent rises from the start of the adsorption of the evaporated fuel, but the temperature changes from the time t _o when the adsorption of the evaporated fuel is almost completed. The temperature of the first adsorbent is reduced by detecting when the maximum temperature is reached by the temperature detector S _1.
It is possible to detect that the adsorption at is almost completed.

Next, the operation of the first embodiment will be described. At the time of 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
The valve 7 is closed to open the third chamber 18 to the atmosphere, but is brought into the first switching state in which the third chamber 18 is shut off from the second evaporated fuel passage 2.

The vaporized fuel generated in the fuel tank T in this state is introduced into the first chamber 16 of the canister C and passes through the first adsorbent filling layer 14 as shown by the arrow,
Adsorbed by the adsorbent. Thus, most of the gas that has flowed through the first adsorbent-packed layer 14 flows from the third chamber 18 into the open passage 24.
And a part of the gas flows from the first adsorbent filling layer 14 to the second adsorbent filling device 15 side.

Next, when it is detected by the temperature detector S ₁ that the adsorption of the evaporated fuel in the first adsorbent packed bed 14 is almost completed, the switching control valve means 20 ₁ is operated by the electromagnetic valve as shown in FIG. The on-off switching valve 26 is closed and the electromagnetic on-off switching valve 27 is opened to shut off the third chamber 18 from the atmosphere, but in a second switching state in which it 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, and the electromagnetic opening / closing switching valve 26 is opened a predetermined time after the opening operation of the electromagnetic opening / closing switching valve 27. Is closed.

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

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

As described above, most of the evaporated fuel circulates in the first adsorbent-filled layer 14 until the adsorption in the first adsorbent-filled layer 14 is almost completed, and the first adsorbent-filled layer 14 has a large amount of fuel vapor. After the adsorption is almost completed, most of the evaporated fuel is made to flow through the second adsorbent filling layer 15, so that a relatively large amount of evaporated fuel is generated in the fuel tank T when the fuel tank T is refueled. However, the ventilation resistance in the canister C can be prevented from becoming larger than the allowable value. For example, when the canister C has an allowable ventilation resistance of 100 mmAq, the L / D of the casing 10 is set so that the first intake agent filling layer 14 and the second intake agent filling layer 15 each have an ventilation resistance of 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 at the time of refueling can be increased.

When the vehicle is parked or stopped, the electromagnetic opening / closing valve 4 is closed, and the switching control valve means 20 ₁ closes both the electromagnetic opening / closing switching valves 26 and 27 to shut off the third chamber 18 from the atmosphere. At the same time, the third switching state is established in which the second evaporated fuel passage 2 is also shut off. As a result, the evaporated fuel 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 filling layer 14, the third chamber 18 and the The HC component is circulated through the second adsorbent-filled layer 15 to reach the second chamber 17, and the HC component is adsorbed in the same manner as in the conventional canister. Therefore, the L / D can be sufficiently increased as in the conventional case, and the vaporized fuel can be sufficiently adsorbed by preventing the migration of the HC component.

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

The passage 3 is formed in the second end wall 12 of the casing 10.
0 is connected, and the third chamber 18 is opened to the atmosphere between the passage 30 and the auxiliary evaporated fuel passage 25 ′ connected to the second evaporated fuel passage 2 and the atmosphere.
And a second switching state that shuts off the third chamber 18 from the atmosphere but communicates with the second evaporated fuel passage 2, and a second switching state that shuts off the third chamber 18 from the atmosphere. Three-port three-position electromagnetic switching valve 2 as switching control valve means capable of switching between a third switching state in which the evaporated fuel passage 2 is also shut off
0 ₂ is provided.

In the casing 10, the H of the third chamber 18 is
An HC detector S ₂ for determining that the adsorption in the first adsorbent packed bed 14 is almost completed by detecting the C concentration and the breakthrough in the first adsorbent packed bed 14 has started is additionally provided.

According to this second embodiment as well, the HC detector S
3 by the electronic control unit ECU according to the detection signal of _2.
By switching and controlling the operation of the port 3 position electromagnetic switching valve 20 ₂ , the same effect as that of the first embodiment can be obtained.

Although the embodiments of the present invention have been described in detail above, 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 claims. It is possible to do.

For example, in the second evaporated fuel passage 2, an on-off valve may be provided between the branch portion of the auxiliary evaporated fuel passages 25, 25 'and the first chamber 16 of the canister C, and the first adsorbent. A timer for measuring the time from the start of refueling to the elapse of a set time may be used as a detector for detecting 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 apparatus dedicated to refueling, which adsorbs evaporative fuel from the fuel tank T only during refueling.

[0031]

As described above, according to the first aspect of the present invention, the cylindrical casing having both ends closed is filled with an adsorbent for adsorbing the evaporated fuel, respectively.
A first chamber, in which the adsorbent-filled layer is provided with a partition wall fixed to one end wall of the casing sandwiched therebetween, and formed between one end face of the first adsorbent-filled layer and one end wall of the casing. An evaporative fuel passage that guides the evaporated fuel from the fuel tank at the time of refueling and a purge gas passage that guides the purge gas to the intake system of the engine are connected to each other, and between the second adsorbent filling layer and the one end wall of the casing. The formed second chamber is open to the atmosphere, and a third chamber common to both the adsorbent-packed layers is formed between the first and second adsorbent-packed layers and the other end wall of the casing. In the device, at least a first switching state in which the third chamber is opened to the atmosphere but is shut off from the vaporized fuel passage and a second switching state in which the third chamber is shut off from the atmospheric air but communicated with the vaporized fuel passage are at least provided. Since it has a switching control valve means that can switch, By switching the second adsorbent-packed layer to adsorb the vaporized fuel, the ventilation resistance of the vaporized fuel in the adsorbent-filled layer is suppressed to a relatively low level so that the vaporized fuel can be sufficiently sent to both adsorbent-filled layers. As a result, sufficient fuel can be supplied to the fuel tank.

The invention according to claim 2 is the above-mentioned claim 1.
In addition to the configuration of the invention described 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 the first adsorbent packed bed when refueling the fuel tank. The first switching state is maintained until it detects that the adsorption of the evaporated fuel is almost completed. However, after the detector detects that the adsorption of the evaporated fuel in the first adsorbent packed bed is almost completed, And the control means for controlling the switching operation of the switching control valve means so as to be in the switching state of No. 2.
By appropriately controlling the switching timing of the adsorbent packed bed, more effective adsorption becomes possible.

[Brief description of drawings]

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

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

FIG. 3 is a diagram showing a configuration of an evaporated fuel processing device in an operating state in a latter half of refueling.

FIG. 4 is a diagram showing a configuration of an evaporated fuel processing device 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 filling layer 15 ... ..Second adsorbent packed bed 16 ... First chamber 17 ... Second chamber 18 ... Third chamber 20 ₁ ... Switching control valve means 20 ₂ ... 3 as 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

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Teruo Wakashiro 1-4-1 Chuo, Wako-shi, Saitama Stock Research Institute Honda Technical Research Institute (72) Inventor Tomoyuki Kawakami 143 Hagadai, Haga-cho, Haga-gun, Tochigi Prefecture Stock company PSG

Claims (2)

[Claims] 1. A tubular casing (1) having both ends closed.
0) the first and second adsorbent packing layers (14, 15) each filled with an adsorbent for adsorbing the evaporated fuel.
Is provided with a partition wall (13) fixed to one end wall (11) of the casing (10) sandwiched therebetween, and one end face of the first adsorbent-filled layer (14) and one end of the casing (10). The first chamber (16) formed between the wall (11) and the vaporized fuel passage (2) for guiding the vaporized fuel from the fuel tank (T) at the time of refueling, and the purge gas for intake air of the engine (E) The purge gas passage (5) leading to the system (7) is connected,
The second chamber (17) formed between the second adsorbent packed bed (15) and the one end wall (11) of the casing (10) is open to the atmosphere, and the first and second adsorbent packed beds (14) are formed. , 15)
In the evaporative fuel treatment apparatus, a third chamber (18) common to both adsorbent packed layers (14, 15) is formed between the second end wall (12) of the casing (10) and the third chamber ( 18) open to the atmosphere but shut off from the evaporative fuel passage (2)
Switching control valve means (20 ₁ , 20 ₂ ) capable of at least switching between the switching state of No. 2 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. A detector (S ₁ , S) 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 detects that the adsorption of the evaporated fuel in the first adsorbent packed bed (14) is almost completed, but in the first adsorbent packed bed (14) After the detectors (S ₁ , S ₂ ) have detected that the adsorption of the evaporated fuel is almost completed, the switching control valve means (20 ₁ , 20 ₂ ) is switched to the second switching state. The evaporated fuel processing apparatus according to claim 1, further comprising a control unit (ECU) for controlling.