JP2002310008A - Fuel vapor treatment equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel vapor treatment equipment capable of preventing the disordering of an air-fuel ratio in a combustion chamber immediately after the start of purging, and improving the exhaust emission. SOLUTION: This fuel vapor treatment equipment is provided with a purge valve 43 on a connecting part of a purge line 42 and a canister 2, in adjacent to the canister. Accordingly, the canister and the purge line are separated when the purge is stopped, which prevents the fuel vapor from being dispersed to the purge line from the canister. Further as the fuel vapor remaining in the purge line is sucked out by the negative pressure of an intake pipe, the fuel vapor does not retain in a space such as the purge line just before the start of purging, which prevents the disordering of the air-fuel ratio in the combustion chamber immediately after the start of purging.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel vapor processing apparatus for preventing fuel vapor generated in a fuel tank from being released to the atmosphere.

[0002]

2. Description of the Related Art Conventionally, in a vehicle such as a vehicle equipped with a gasoline engine using highly volatile oil (for example, fuel such as gasoline), fuel vapor (also referred to as evaporative gas or vapor) volatilized in a fuel tank is released to the atmosphere. In order to prevent the release, a fuel vapor treatment device is installed, the fuel vapor is temporarily adsorbed on the activated carbon in the canister, and the canister is purged using an intake pipe negative pressure or pumping means such as a pump during engine operation. Then, the fuel vapor adsorbed on the activated carbon is sent to the engine for combustion. At this time, the amount of purge fuel vapor is controlled by the purge valve in accordance with the operating state of the engine, and even if the purge fuel vapor flows into the combustion chamber, the exhaust pipe is maintained so that the combustion chamber is maintained at the stoichiometric air-fuel ratio. Feedback control for controlling the fuel injection amount is performed by using the output of an oxygen (O ₂ ) sensor, an air-fuel ratio (A / F) sensor, or the like, which is attached to the engine.

In recent years, with the tightening of regulations on exhaust gas emitted from vehicles, the air-fuel ratio in the transient state has been disturbed, for example, immediately after the start of purging. Exhaust gas discharged during the period until the air-fuel ratio returns to the air-fuel ratio has become a problem.

[0004] The configuration of a conventional fuel vapor processing apparatus is shown in FIG.
As shown in the figure, the fuel tank 1 and the canister 2 are arranged at the rear of the vehicle, the engine is arranged at the front of the vehicle, and the purge valve 43 is installed near the connection between the intake pipe 5 of the engine and the purge passage 42. There are many cases. In this fuel vapor processing apparatus, a detector was connected immediately after the purge valve 43, and the amount of purge fuel vapor coming out of the purge valve 43 immediately after the start of purging was measured.
As shown in the graph above, the fuel vapor amount fluctuated greatly in a few seconds after the start of the purge, and it was found that this caused the turbulence of the air-fuel ratio in the combustion chamber during the transition immediately after the start of the purge.

The fuel vapor amount obtained as a result includes fuel vapor accumulated in a space such as a purge passage 42 connecting the canister 2 and the intake pipe 5 and fuel vapor desorbed from the activated carbon C of the canister 2. Yes, and the results of evaluating each of these for each layer are shown in the lower graph of FIG.
From this result, the fluctuation of the fuel vapor amount for a few seconds immediately after the start of the purge indicates that the purge valve
It was found that fuel vapor was accumulated in the space between No. 3 and activated carbon C. Further, it was found that the fuel vapor accumulated in this space was diffused from the canister 2 to the purge passage 42 when the purge was stopped.

The vaporized fuel evaporation prevention apparatus disclosed in Japanese Patent Application Laid-Open No. 11-30158 is provided with a fuel vapor pumping means such as a purge pump for forcibly pumping fuel vapor in a canister to an intake pipe in the middle of a purge passage. But
In this conventional technique, the purge valve is provided in the middle of the purge passage. As described above, conventionally, the installation position of the purge valve is not particularly determined, and is often installed near the intake pipe as shown in FIG. 11 for reasons such as mountability. With this configuration, it is impossible to prevent the fuel vapor from diffusing from the canister into the purge passage when the purge is stopped, so that the fuel vapor accumulates in the purge passage between the canister and the purge valve.

In recent years, canisters are often installed near the fuel tank at the rear of the vehicle due to the strengthening of the ORVR regulations and the like, so that the purge passage has become longer. Furthermore, the use of a direct injection engine or the like tends to increase the cross-sectional area of the purge passage in order to reduce the pressure loss in the purge passage so that even an engine having a small intake pipe negative pressure can be sufficiently purged. For this reason, the space (volume) in the purge passage is increased, and the amount of fuel vapor accumulated in the space is increased accordingly. Therefore, the disturbance of the air-fuel ratio due to the influence of the purge immediately after the start of the purge is increased, and the exhaust emission tends to be deteriorated. It is in.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to reduce the amount of fuel vapor that does not accumulate in a purge passage or the like when a purge is stopped, or to reduce the amount of fuel vapor accumulated. An object of the present invention is to provide a fuel vapor processing apparatus capable of improving the exhaust emission by eliminating or reducing the disturbance of the air-fuel ratio in the combustion chamber immediately after the start of the purge.

[0009]

According to the present invention, there is provided a fuel vapor processing apparatus according to the present invention as means for solving the above-mentioned problems. In the fuel vapor processing apparatus according to the first aspect, the purge valve is provided at a connection portion between the purge passage and the canister, and is disposed adjacent to the canister. Accordingly, when the purge is stopped, the purge valve is closed, so that the canister and the purge passage are separated from each other, and diffusion of the fuel vapor from the canister to the purge passage is prevented. Since the fuel vapor remaining in the purge passage is sucked out by the negative pressure of the intake pipe, the amount of fuel vapor accumulated in the space such as the purge passage immediately before the start of the purge is almost zero. No disturbance in fuel ratio occurs.

According to a second aspect of the present invention, a purge valve is provided in a purge port of the canister. Accordingly, when the purge is stopped, the purge valve is closed to separate the canister from the purge passage, and the fuel vapor remaining in the purge passage is sucked out by the negative pressure of the intake pipe. It works.
In the fuel vapor processing apparatus according to the third aspect, a purge valve is provided adjacent to the canister, and a three-way valve having one end opened to the atmosphere is provided adjacent to the purge valve on the intake pipe side of the purge valve. The atmosphere is switched to the atmosphere side, and the inside of the purge passage is scavenged with the atmosphere. Accordingly, the same operation and effect as those of the device according to the first and second aspects are obtained.

According to a fourth aspect of the present invention, in the fuel vapor processing apparatus, a purge valve is installed near the intake pipe, a three-way valve having one end connected to the atmosphere is installed adjacent to the canister, and the three-way valve is set to the atmosphere side immediately before the purge is stopped. The purge is stopped after purging the purge passage with the atmosphere. Thereby, since the three-way valve is connected to the atmosphere side, the canister and the purge passage are separated, and diffusion of the fuel vapor from the canister to the purge passage is prevented.
Also, since the fuel vapor remaining in the purge passage is scavenged by the atmosphere, the amount of fuel vapor accumulated in the space such as the purge passage is almost zero immediately before the purge is started. No disturbance occurs.

The fifth and sixth aspects are intended to reduce the volume of the air layer near the purge port in the canister. Therefore, in the fuel vapor treatment apparatus of the fifth aspect, the fuel adsorbing layer in the canister is provided. The end face facing the purge port is formed so as to be equidistant from the purge port, and in the fuel vapor processing apparatus according to claim 6, the end face of the fuel adsorbing layer in the canister gradually moves toward the purge port. The connection structure between the end face and the purge port is adopted so that an air layer is formed so as to restrict the air flow.
Thus, the amount of fuel vapor accumulated in the space inside the canister can be reduced. This provides a further effect when combined with the means of claims 1 to 4.

According to a seventh aspect of the present invention, a canister is provided near an intake pipe of an internal combustion engine adjacent to a purge valve. By closing the purge valve when the purge is stopped, the canister and the purge passage are separated from each other, and the diffusion of the fuel vapor from the canister to the purge passage is prevented. In this configuration, since the distance between the canister and the intake pipe is short, the purge passage is short, and even if fuel vapor remains in the purge passage, it is very small, and the air-fuel ratio in the combustion chamber does not disturb immediately after the start of the purge. . In the fuel vapor processing apparatus according to the eighth aspect, an opening / closing valve is provided at a connection portion between the canister and the purge passage, separately from the purge valve for controlling the start, stop, and flow rate of the purge. Closes the on-off valve to suck out residual fuel vapor in the purge passage, closes the barge valve, and closes the on-off valve while the purge is stopped, so that fuel vapor can be prevented from flowing out of the canister to the purge passage. The fuel vapor does not accumulate in the passage, and the air-fuel ratio is not disturbed when the purge is restarted.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a fuel vapor processing apparatus according to an embodiment of the present invention will be described with reference to the drawings. FIG.
1 is an overall configuration diagram of a fuel vapor processing device according to a first embodiment of the present invention, and FIG. 2 is a cross-sectional view of a canister. As shown in FIG. 1, a fuel tank 1 is installed at the rear of the vehicle, and a canister 2 connected to the fuel tank 1 via a fuel vapor passage (evaporation line) 41 is an ORV.
It is necessary to quickly adsorb a large amount of fuel vapor generated at the time of refueling in order to comply with R regulations and the like, and is installed near the fuel tank 1.

A case 21 forming an outer wall of the canister 2
The inside is filled with activated carbon C as an adsorbent to form a fuel adsorption layer 22. Perforated plates 23 and 24 are provided at both ends of the fuel adsorbing layer 22, and sandwich the fuel adsorbing layer 22. Air layers 25, 26, 27 are formed between the left and right ends of the case 21 and the perforated plates 23, 24, respectively, so that the fuel vapor or the atmosphere is evenly distributed to the fuel adsorption layer 22. The perforated plates 23 and 24 and the fuel adsorbing layer 22
Filters 28 and 29 are arranged between the two to prevent the activated carbon C from falling off.

An evaporation port 30 and a purge port 31 are provided at one end of the case 21, and an atmosphere port 32 connected to the atmosphere is provided at the other end of the case 21. The evaporation port 30 is connected to the fuel tank 1 via an evaporation line 41 which is a fuel vapor passage. Purge port 31
Is connected to an intake pipe 5 of an internal combustion engine (engine) via a purge line 42 as a purge passage. At the connection between the purge line 42 and the purge port 31, a purge valve 43 for controlling the start, stop and flow rate of the purge is provided adjacent to the canister 2. A fuel tank 1 is provided between the evaporation port 30 and the purge port 31.
A partition 33 is provided to prevent the fuel vapor generated from the fuel vapor from flowing directly to the purge line 42 without passing through the fuel adsorption layer 22.

Next, the operation of the fuel vapor processing apparatus according to the first embodiment configured as described above will be described. When the engine is stopped (when the vehicle is left unattended), the fuel vapor generated in the fuel tank 1 as the outside air temperature rises increases.
Flows into the canister 2 and is adsorbed on the activated carbon C.
When the engine is operating, the inside of the intake pipe 5 has a negative pressure. When the purge valve 43 is opened, outside air is introduced into the canister 2 from the atmosphere port 32. Fuel vapor generated in the fuel tank 1 at the time of engine stop or refueling is adsorbed on the activated carbon C of the fuel adsorbing layer 22 in the canister 2, and fuel vapor is desorbed from the activated carbon C by the introduced outside air,
The gas is introduced into the intake pipe 5 from the purge port 31 through the purge valve 43 and the purge line 42, and is burned by the engine.

When the purge valve 43 is closed to stop the purging, in the conventional configuration as shown in FIG.
As described above, the purge valve 43 is installed near the connection between the purge valve 42 and the purge line 42.
When the fuel cell 3 is closed, fuel vapor desorbed from the activated carbon C is left in the purge line 42, or fuel vapor generated from the fuel tank 1 while the purge valve 43 is closed diffuses from the canister 2 into the purge line 42. As a result, fuel vapor accumulates in the purge line 42, and this causes fluctuation in the amount of purge fuel vapor when the next purge valve 43 is opened (see the upper graph in FIG. 10).
However, in the configuration of the first embodiment shown in FIG. 1, since the purge valve 43 is installed adjacent to the canister 2, when the purge valve 43 is closed when the purging is stopped, the fuel vapor diffuses from the canister 2 to the purge line 42. Can be prevented. Fuel vapor remaining in the purge line 42 is sucked out into the intake pipe 5 by the negative pressure of the intake pipe 5,
There is no accumulation in the purge line 42.

Therefore, since the fuel vapor remains only in the air layer 27 near the purge port 31 of the canister 2, the amount of the retained fuel vapor is very small, and the purge valve 43 is opened next. Sometimes, the fluctuation of the purge fuel vapor for a few seconds from the start of the purge becomes very small. This behavior is shown in the lower graph of FIG. As can be seen from this graph, after the purge is started, the amount of fuel vapor gradually increases without abruptly changing, so that the air-fuel ratio control is easy. In addition, the graph of FIG. 10 shows the negative pressure of the intake pipe −7 kPa,
It was measured when the purge valve was fully opened.

FIG. 3 shows a second embodiment. In the second embodiment, the installation position of the purge valve 43 is different from the purge line 42 and the purge port 31 of the first embodiment.
A purge valve 43 is installed in the purge port 31 of the canister 2 in place of the connection part, and the other configuration is the same as that of the first embodiment, and the description is omitted. Also in the second embodiment, when the purge valve 43 is closed as in the first embodiment, diffusion of fuel vapor from the canister 2 to the purge line 42 is prevented, and fuel vapor remaining in the purge line 42 is prevented. Is gradually sucked out by the negative pressure of the intake pipe 5, and the fluctuation of the purge fuel vapor for a few seconds from the start of the purge hardly occurs. Therefore, the air-fuel ratio of the combustion chamber does not greatly change at the time of purging. Further, in the second embodiment, since the purge valve 43 and the canister 2 are integrated, the cost can be reduced.

FIG. 4 shows a third embodiment. In the third embodiment, a purge valve 43 is provided at a connection between the purge line 42 and the canister 2, and a three-way valve 61 is provided at a connection between the purge valve 43 and the purge line 42. That is, the three-way valve 61 and the purge valve 43 are installed adjacent to the purge line 42 and close to the canister 2. One end of the three-way valve 61 is connected to the purge line 42, the other end is connected to the purge valve 43, and the other end is connected to the atmosphere via the air passage 62. A close valve 63 is provided at an end of the air passage 62. The three-way valve 61 has a structure that switches between the purge valve 43 side and the atmosphere side. The structure of the canister 2 itself is the same as that of FIG.

Next, the operation of the fuel vapor processing apparatus according to the third embodiment will be described. When the engine is stopped, the purge valve 43 is closed and the three-way valve 61 is switched to the atmosphere side. Therefore, even if the fuel vapor leaks from the purge valve 43, the diffusion of the fuel vapor to the purge line 42 is prevented. Further, in order to prevent oil leakage from a fuel injection device (not shown) and fuel adhering to the intake system of the engine from diffusing and leaking from the purge line 42 to the atmosphere via the three-way valve 61, a close valve 63 is provided. Is closed.

To start purging during operation of the engine, the three-way valve 61 is switched to the purge valve 43 and the purge valve 43 is opened. Atmospheric port 3 by suction pipe negative pressure
Atmosphere is introduced into the canister 2 from the canister 2, the fuel vapor is desorbed from the activated carbon C by the introduced atmosphere, passed out of the purge port 31, passes through the purge valve 43 and the purge line 42, is led to the intake pipe 5, and is combusted by the engine. . To stop purging, the three-way valve 61 is switched to the atmosphere side, the purge valve 43 is closed, and the close valve 63 is opened. The atmosphere is introduced from the close valve 63 by the intake pipe negative pressure, and the inside of the purge line 42 is scavenged by the atmosphere. Therefore, the fuel vapor remaining in the purge line 42 is sent to the engine, and the fuel vapor remaining in the purge line 42 is completely eliminated. Then, after a predetermined amount of air sufficient to scavenge the inside of the purge line 42 flows, the close valve 63 is closed.

Since the mixture of fuel vapor and air flows from the purge line 42 to the intake pipe 5 until the inside of the purge line 42 is scavenged and the clove valve 63 is closed, the engine of the engine is closed until the close valve 63 is closed. In the air-fuel ratio control, it is necessary to perform the same control as when performing the purge. In the first embodiment described above, the fuel vapor retained in the purge line 42 is waited for to be naturally sucked out by the suction pipe negative pressure. Although fuel vapor may remain, in the third embodiment, since the gas is forcibly scavenged by the atmosphere, the fuel vapor in the purge line 42 can be completely eliminated in a short period of time.

FIG. 5 shows a fourth embodiment. In the fourth embodiment, a purge valve 43 is installed at a connection between the purge line 42 and the intake pipe 5, and a three-way valve 61 is installed at a connection between the canister 2 and the purge line 42. That is, the purge valve 43 is provided near the intake pipe 5, and the three-way valve 61 is provided near the canister 2. One end of the three-way valve 61 is connected to the purge line 42, the other end is connected to the purge port 31 of the canister 2, and the other end is connected to the atmosphere via the air passage 62. The three-way valve 61 has a structure for switching between the canister 2 side and the atmosphere side. The structure of the canister 2 is the same as that of FIG.

Next, the operation of the fuel vapor processing apparatus according to the fourth embodiment will be described. When the engine is stopped, the purge valve 43 is closed.
The three-way valve 61 is switched to the atmosphere side in order to prevent fuel vapor from diffusing into the air. To start purging during operation of the engine, the three-way valve 61 is switched to the canister 2 side and the purge valve 43 is opened. The atmosphere is introduced into the canister 2 from the atmosphere port 32 by the intake pipe negative pressure, and the introduced atmosphere releases fuel vapor from the activated carbon C, passes from the purge port 31 through the purge line 42 and the purge valve 43, and passes through the intake pipe 5. And is combusted by the engine.

When the purging is stopped, when the three-way valve 61 is switched to the atmosphere side, the atmosphere is introduced by the suction pipe negative pressure, and the inside of the purge line 42 is scavenged by the atmosphere. Therefore, the fuel vapor remaining in the purge line 42 is sent to the engine, and the fuel vapor remaining in the purge line 42 is completely eliminated. Then, the purge valve 43 is closed after a predetermined amount of air flows enough to scavenge the inside of the purge line 42. Note that the purge line 4 is not purged until the inside of the purge line 42 is purged and the purge valve 43 is closed.
Since the mixture of fuel vapor and air flows out of the intake pipe 5 into the intake pipe 5, the air-fuel ratio control of the engine needs to be performed in the same manner as when performing the purge until the purge valve 43 is closed.
In the fourth embodiment as well, the scavenging is forcibly performed as in the third embodiment, so that the fuel vapor in the purge line 42 can be completely eliminated in a short period of time.

FIG. 6 shows a fifth embodiment. In the fifth embodiment, the purge port 3 of the canister 2
The end face of the fuel adsorbing layer 22 near 1 is configured so that the air layer 27 is small enough to be at the same distance from the purge port 31 and not to impede the flow of air such as an increase in pressure loss. That is, the fuel adsorption layer 22 facing the purge port 31
A hemispherical concave portion is formed on the end surface of the airbag, and the air layer 27 has a hemispherical shape. In this case, the fuel vapor retained in the space shown in the lower graph of FIG. 12 includes the fuel vapor retained in the air layer 27. Note that a conical concave portion instead of a hemispherical shape may be formed on the end surface of the fuel adsorption layer 22. The structure of the canister 2 other than the above is the same as that of FIG. In the fifth embodiment, since the volume of the air layer 27 is made as small as possible, the amount of fuel vapor retained in the air layer 27 is also small. Therefore, the disturbance of the air-fuel ratio at the start of the purge can be reduced.

FIG. 7 shows a sixth embodiment. In the sixth embodiment, the purge port 31 of the canister 2 is used.
The air layer 27 gradually becomes smaller from the end face of the fuel adsorption layer 22 in the vicinity, and is connected to the purge port 31. That is, the purge port 31 is formed in a funnel shape in the fuel adsorption layer 22.
Is connected to the end face. The connection structure is not limited to the funnel shape, and may be a pyramid-shaped connection structure. The other structure of the canister 2 is the same as that of FIG. By adopting this connection structure, the volume of the air layer 27 is reduced as much as possible in the same manner as in the above-described fifth embodiment, and the fuel vapor layer that stays in the air layer 27 is reduced. Therefore, even in this case, the disturbance in the air-fuel ratio at the start of the purge can be reduced.

In the fifth and sixth embodiments,
Although described as independent embodiments, these embodiments may be combined with any one of the fifth and the first to fourth, or combined with any of the sixth and the first to the fourth, and the like. It can be easily understood that further effects can be obtained by appropriately combining with other embodiments. It is also possible to combine the fifth and sixth embodiments with the seventh and eighth embodiments described later.

FIG. 8 shows a seventh embodiment. In the seventh embodiment, both the purge valve 43 and the canister 2 are installed near the intake pipe 5 in front of the vehicle. The structure of the canister 2 is the same as that of FIG. In this case, since the purge valve 43 and the canister 2 are installed adjacent to each other, diffusion of the fuel vapor from the canister 2 to the purge line 42 is prevented. Further, since the distance between the canister 2 and the intake pipe 5 is short, the purge line 4
2 has a small volume, and the purge line 42 is
Only a small amount of fuel vapor remains inside. For this reason, disturbance of the air-fuel ratio at the start of the purge can be reduced.

In the first embodiment, since the distance between the intake pipe 5 and the purge valve 43 is long, it is necessary to consider the time delay due to the transport delay when controlling the purge flow rate. In the configuration of the embodiment, since the distance between the intake pipe 5 and the purge valve 43 is short, the purge flow rate can be controlled without having to consider a time delay. In addition,
In the configuration of the seventh embodiment, since the distance between the fuel tank 1 and the canister 2 is long, it is necessary to increase the inner diameter of the evaporation line 41 in order to reduce the pressure loss in order to comply with the ORVR regulations.

FIG. 9 shows an eighth embodiment. The canister 2 is installed at the rear of the vehicle, and the purge valve 43 is installed at the front of the vehicle. An open / close valve 44 is provided at a connection between the canister 2 and the purge line 42. The structure of the canister 2 is the same as that of FIG. The operation of the fuel vapor processing device according to the eighth embodiment will be described. When purging is started during operation of the engine, the open / close valve 44 is opened, and the purge valve 43 is opened. Atmospheric pressure is introduced into the canister 2 from the atmosphere port 32 of the canister 2 by the intake pipe negative pressure, and fuel vapor is desorbed from the activated carbon C by the introduced atmosphere. After passing through 43, it is led to the intake pipe 5 and burned by the engine. When the purging is stopped, the open / close valve 44 is closed, the residual fuel vapor in the purge line 42 is sucked out, and then the purge valve 43 is closed. By closing the open / close valve 44, it is possible to prevent fuel vapor from flowing out of the canister 2 to the purge line 42 during the stop of the purge. Therefore, fuel vapor does not accumulate in the purge line 42 while the purge is stopped, and it is possible to prevent the air-fuel ratio from being disturbed when the purge is restarted.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of a fuel evaporation processing apparatus according to a first embodiment of the present invention.

FIG. 2 is a sectional view of a canister.

FIG. 3 is a cross-sectional view of a canister showing an installation position of a purge valve in a fuel evaporation system according to a second embodiment of the present invention.

FIG. 4 is an overall configuration diagram of a fuel evaporation processing apparatus according to a third embodiment of the present invention.

FIG. 5 is an overall configuration diagram of a fuel evaporation processing apparatus according to a fourth embodiment of the present invention.

FIG. 6 is a sectional view of a canister in a fuel evaporation system according to a fifth embodiment of the present invention.

FIG. 7 is a sectional view of a canister in a fuel evaporation system according to a sixth embodiment of the present invention.

FIG. 8 is an overall configuration diagram of a fuel evaporation processing apparatus according to a seventh embodiment of the present invention.

FIG. 9 is an overall structural diagram of a fuel evaporation processing apparatus according to an eighth embodiment of the present invention.

FIG. 10 is a graph comparing the fluctuation of the fuel evaporation amount immediately after the start of purge with the present invention and the prior art.

FIG. 11 is an overall configuration diagram of a conventional fuel evaporation processing apparatus.

FIG. 12 is a graph showing the result of measuring the amount of fuel vapor immediately after the start of purging in a conventional fuel vapor processing apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Fuel tank 2 ... Canister 5 ... Intake pipe 22 ... Fuel adsorption layer 23, 24 ... Perforated plate 25, 26, 27 ... Air layer 28, 29 ... Filter 30 ... Evaporation port 31 ... Purge port 32 ... Atmospheric port 41 ... Evaporation line ( (Fuel vapor passage) 42: purge line (purge passage) 43: purge valve 61: three-way valve

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification FI FI Theme Court ゛ (Reference) F02M 25/08 F02M 25/08 311G (72) Inventor Naoya Kato 14 Iwatani Shimowasukamachi, Nishio-shi, Aichi Prefecture Inside the Japan Auto Parts Research Institute (72) Inventor Masaki Takeyama 14 Iwatani, Shimowasumi-machi, Nishio-shi, Aichi Prefecture Inside the Japan Auto Parts Research Institute (72) Inventor Yuji Miyanoo 1 Toyota Town, Toyota-shi, Aichi Prefecture Toyota Auto (72) Inventor Kenji Kasashima 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Corporation F-term (reference) 3G044 BA03 BA08 CA13 DA02 GA01 GA02 GA12 GA14

Claims (8)

[Claims] An end of a canister filled with an adsorbent in a case to form a fuel adsorbing layer is communicated with a fuel vapor passage leading to a fuel tank and a purge passage leading to an intake pipe of an internal combustion engine. The other end is communicated with the atmosphere, and the fuel vapor discharged from the fuel tank to the fuel vapor passage is temporarily adsorbed and held in the fuel adsorbing layer of the canister. In a fuel vapor processing apparatus configured to be desorbed from an adsorbent layer and sent through the purge passage to the intake pipe, a purge valve for controlling start, stop, and flow of purge is connected between the purge passage and the canister. A fuel vapor treatment device, which is disposed adjacent to the canister. 2. The fuel vapor processing apparatus according to claim 1, wherein an installation position of the purge valve is installed in a purge port of the canister instead of a connection between the purge passage and the canister. 3. A three-way valve having one end connected to the atmosphere is provided adjacent to the intake pipe of the purge valve, and when purging is stopped, the three-way valve is switched to the atmosphere to scavenge the inside of the purge passage. The fuel vapor processing device according to claim 1 or 2, wherein 4. A canister filled with an adsorbent in a case to form a fuel adsorbing layer has one end communicating with a fuel vapor passage leading to a fuel tank and a purge passage leading to an intake pipe of an internal combustion engine. The other end is communicated with the atmosphere, and the fuel vapor discharged from the fuel tank to the fuel vapor passage is temporarily adsorbed and held in the fuel adsorbing layer of the canister. In a fuel vapor processing apparatus configured to be desorbed from an adsorption layer and sent out to the intake pipe through the purge passage, a purge valve is installed near a connection between the intake pipe and the purge passage of an internal combustion engine, At the connection between the purge passage and the canister, a three-way valve having one end connected to the atmosphere is installed adjacent to the canister. Scavenging to fuel vapor treatment device characterized by stopping the purging from. 5. One end of a canister filled with an adsorbent in a case to form a fuel adsorbing layer is communicated with a fuel vapor passage leading to a fuel tank and a purge passage leading to an intake pipe of an internal combustion engine. The other end is communicated with the atmosphere, and the fuel vapor discharged from the fuel tank to the fuel vapor passage is temporarily adsorbed and held in the fuel adsorbing layer of the canister. In the fuel vapor treatment device configured to be desorbed from the adsorption layer and sent out to the intake pipe through the purge passage, in order to reduce the volume of an air layer formed near the purge port inside the canister, The inside of the case is arranged so that the end surface of the fuel adsorbing layer is equidistant from the purge port, that is, the end surface of the fuel adsorbing layer facing the purge port forms a hemispherical concave portion. Fuel vapor processing apparatus, characterized in that said adsorbent is filled. 6. One end of a canister filled with an adsorbent in a case to form a fuel adsorbing layer is communicated with a fuel vapor passage leading to a fuel tank and a purge passage leading to an intake pipe of an internal combustion engine. The other end is communicated with the atmosphere, and the fuel vapor discharged from the fuel tank to the fuel vapor passage is temporarily adsorbed and held in the fuel adsorbing layer of the canister. In the fuel vapor treatment device configured to be desorbed from the adsorption layer and sent out to the intake pipe through the purge passage, in order to reduce the volume of an air layer formed near the purge port inside the canister, The fuel vapor processing device, wherein the air layer is formed so as to be gradually narrowed from the end face of the fuel adsorption layer toward the purge port. 7. One end of a canister filled with an adsorbent in a case to form a fuel adsorbing layer is communicated with a fuel vapor passage leading to a fuel tank and a purge passage leading to an intake pipe of an internal combustion engine. The other end is communicated with the atmosphere, and the fuel adsorbing layer of the canister temporarily absorbs and holds the fuel vapor discharged from the fuel tank to the fuel vapor passage. In a fuel vapor processing apparatus configured to be desorbed from an adsorbent layer and sent to the intake pipe through the purge passage, a purge valve and the canister are provided adjacent to the intake pipe of the internal combustion engine. A fuel vapor processing device characterized by the above-mentioned. 8. One end of a canister filled with an adsorbent in a case to form a fuel adsorbing layer is communicated with a fuel vapor passage leading to a fuel tank and a purge passage leading to an intake passage of an internal combustion engine. The other end is communicated with the atmosphere, and the fuel vapor discharged from the fuel tank to the fuel vapor passage is temporarily absorbed and held in the fuel adsorbing layer, and is desorbed when the internal combustion engine is operated, and the fuel vapor is released from the purge passage. A fuel vapor processing apparatus configured to be delivered to an intake passage, wherein an open / close valve is provided at a connection between a canister and a purge passage, separately from a purge valve for controlling start, stop, and flow rate of purge.