JPH11280569A - Evaporated fuel discharge prevention device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To miniaturize an evaporation system. SOLUTION: A solenoid valve 100 is incorporated into a canister casing 305 by disposing a solenoid valve 100 in first space 304 formed by reducing an elongating direction dimension L2 of a second adsorbing chamber 302 below an elongating direction dimension L1 of a first adsorbing chamber 301. As a result, because space for disposing a new solenoid valve 100 is not required, an evaporation system can be miniaturized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel vapor emission prevention device (evaporation system) for preventing vaporized fuel vaporized in a fuel tank of an internal combustion engine (engine) from being released into the atmosphere. .

[0002]

2. Description of the Related Art As a conventional evaporative system, for example,
An evaporative system disclosed in FIG. 4 of JP-A-5-340316 is known. According to this technique, a partition plate is provided in the casing of the canister 3, and the partition plate allows the left adsorption chamber (first adsorption chamber) packed with activated carbon and the right adsorption chamber (first adsorption chamber) filled with activated carbon ( Second
The adsorption chamber on the right side has a larger cross-sectional area with respect to the flow of the fuel vapor than the adsorption chamber on the left side.

The casing is provided with an atmosphere port communicating with the atmosphere via an air cleaner 7, a purge port communicating with the intake pipe 2, and an introduction port communicating with the fuel tank 1. And a solenoid valve 5 for controlling the introduction of air or the shutoff of air.
Is provided.

[0004]

By the way, in order to cope with the new regulation of fuel vapor in the United States, the ORVR regulation (regulation at the time of refueling), it is necessary to reduce the pressure loss at the time of refueling. To this end, it is a matter of course that the cross-sectional area of the first adsorption chamber is increased, and that the cross-sectional area of the second adsorption chamber is increased.

However, when the volume of the second suction chamber is the same as that of the conventional one, the length of the second suction chamber extending toward the introduction port is smaller than the length of the first suction chamber extending toward the introduction port. (2) A dead space is generated on the side of the adsorption chamber, so that the dead space cannot be effectively utilized, which is against the demand for downsizing of the evaporation system. The present invention has been made in view of the above circumstances, and has as its object to reduce the size of an evaporative system.

[0006]

The present invention uses the following technical means to achieve the above object. Claim 1
In the invention described in Item 4, the length (L ₁ ) of the second suction chamber (302) extending toward the introduction port (307a) is increased by the first suction chamber (301) extending toward the introduction port (307a). By making it smaller than the length (L ₂ ) of
A first space (304) is formed on the introduction port (307a) side of the second adsorption chamber (302).
The electromagnetic valve (100) is arranged in the space (304).

[0007] This eliminates the need for a space (space) for newly disposing the solenoid valve (100), thereby making it possible to reduce the size of the evaporation system. Further, since the first and second adsorption chambers (301, 302) and the solenoid valve (100) are integrated in the canister casing (305), the piping for connecting these 100, 301, 302 must be eliminated. Can be. Therefore, the number of piping connections in the evaporative system can be reduced, so that the airtightness (reliability) of the evaporative system can be improved.

The first and second suction chambers (301, 302)
And the piping connecting the solenoid valve (100) can be eliminated, so that the ventilation resistance of the passage from the fuel tank (200) to the solenoid valve (100) through the first and second adsorption chambers (301, 302) is reduced. can do. Therefore,
When refueling the fuel tank (200), the fuel tank (20
Since the air in 0) can be quickly discharged to the atmosphere side, it is possible to refuel quickly.

According to the second aspect of the present invention, the first space (3
04), a pressure detecting means (240) for detecting the pressure in the second suction chamber (302) is provided, and the first space (304) is provided in the canister casing (305).
It is characterized by being covered with. As a result, the pressure detecting means (240) is not directly exposed to the atmosphere, and foreign matter does not directly collide with the pressure detecting means (240), so that the pressure detecting means (240) can be protected. .

According to the third aspect of the present invention, the second space provided parallel to the first suction chamber (301) and the second suction chamber (302) and provided in the canister casing (305). (306), and the second space (30)
6) communicates with the first space (304) and prevents entry of foreign matter between the second space (306) and the atmosphere port (307c) provided in the canister casing (305) and communicating with the atmosphere. (310) is provided.

As a result, the canister casing (30)
Without increasing the size of 5), the filtration area of the filter (310) can be easily increased by effectively utilizing the length (L ₁ ) of the first adsorption chamber (301). Further, since air from which foreign matter has been removed by the filter (310) flows into the first space (304), the pressure detecting means (240)
Foreign matter can be prevented from entering the pressure detecting means (24).
0) reliability (durability) can be improved.

The invention according to claim 4 is characterized in that the introduction port (307a), the purge port (307b) and the atmosphere port (307c) are open in the same direction. Thereby, each port (307a-30)
The workability when connecting the pipe to 7c) can be improved.

Incidentally, the reference numerals in the parentheses of the above-mentioned means show examples of the correspondence with specific means described in the embodiments described later.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) FIG. 1 is a conceptual diagram of an evaporation system (fuel vapor emission prevention device) according to the present embodiment. Intake pipe 23 of internal combustion engine 220
0 is a fuel pipe (fuel passage means). In the middle of the fuel pipe 210, a charcoal canister (hereinafter abbreviated as a canister) 300 that adsorbs vaporized fuel with activated carbon.
The solenoid valve 100 is connected to the open side of the canister 300. The solenoid valve 1
00 is a normal state with the canister 30 in the most opened state.
0 is communicated with the atmosphere side.

Then, the fuel tank 2 of the fuel pipe 210
A pressure sensor (pressure detecting means) 240 for detecting the pressure in the fuel pipe 210 (canister 300) is provided between the fuel pipe 210 and the canister 300, while the canister 300 and the intake pipe 230 of the fuel pipe 210 are connected to each other. Between them, a purge solenoid valve (valve means) 250 for opening and closing the fuel pipe 210 is provided. Incidentally, reference numeral 260 denotes an air cleaner box in which an air filter (not shown) for removing dust (foreign matter) in the air taken into the intake pipe 230 (engine 220) is stored.

The purge solenoid valve 250 and the solenoid valve 1
00 is controlled by an electronic control unit (ECU) 270, and the detection signal of the pressure sensor 240 is
Is input to Next, the canister 300 will be described. As shown in FIG. 2, the canister 300 is connected to the fuel tank 200 side and adsorbs vaporized fuel, and a second adsorption chamber 302 that adsorbs evaporated fuel desorbed from the first adsorption chamber 301. have. As shown in FIG. 3, the two adsorbing chambers 301 and 302 are formed to extend (extend) in the left-right direction on the paper in parallel so that the vaporized fuel flow is turned back at the connecting portion 303 between the two adsorbing chambers 301 and 302. It is, and the extension dimension L ₂ of the second adsorption chamber 302 is smaller than the extension dimension L ₁ of the first adsorption chamber 301.

Here, the extension direction is a direction in which the second suction chamber 302 extends toward an introduction port 307a described later. Therefore, one end of the second suction chamber 302 in the direction of extension (the side opposite to the connecting portion 303) is located at one end in FIG.
As shown in FIG. 3, a first space 304 is formed. The solenoid valve 100 is connected to the second suction chamber 302 in the first space 304.

In FIG. 2, reference numeral 305 denotes both adsorption chambers 301,
A resin canister casing that constitutes the casing of the second space 302 and the second space 306 and covers (shields) the first space 304. An introduction port (tank port) 307 connected to the fuel tank 200 side for introducing the evaporated fuel is provided in the canister casing 305.
a, a purge port 307b communicating with the engine 220 (purge solenoid valve 250) and an atmosphere port 307c communicating with the atmosphere are formed, and these ports 307a to 307c open in the same direction. ing.

Incidentally, the canister casing 305 is
Casing body 305a and first to third lids (caps) 30
5b to 305d, the first lid 305b opens and closes when the activated carbon in the adsorption chambers 301 and 302 is charged or exchanged, and the second lid 305c is used for assembling or exchanging a filter described later. The third cover 305d opens and closes when the solenoid valve 100 is assembled or replaced.

Incidentally, the second space 306 is formed so as to extend over substantially the entire area of the extension direction dimension L _{1 in} parallel with the extension direction of the first suction chamber 301.
Communicate with each other through a communication hole 309. The second space 306 communicates with the atmosphere port 307c via a filter 310 that removes foreign substances, and the filter 310 is disposed over the entire area of the second space 306 in the extending direction.

Here, the airtightness check operation of the evaporation system will be described (see FIG. 1). First, the intake pipe 23
0, the fuel pipe 210 including the canister 300
When the internal pressure decreases, the purge solenoid valve 250 and the solenoid valve 100 are closed. A pressure change in the fuel pipe 210 from the fuel tank 200 to the purge solenoid valve 250 is detected by the pressure sensor 240, and the degree of air tightness of the fuel system is determined from the degree of the pressure change. The solenoid valve 100 is open except when the airtightness of the evaporation system is checked.

Next, the features of this embodiment will be described. According to this embodiment, provided the solenoid valve 100 to the first space 304 formed by the elongated dimension L ₂ of the second adsorption chamber 302 smaller than the extension dimension L ₁ of the first adsorption chamber 301 Therefore, a space (space) for newly disposing the solenoid valve 100 is not required. Therefore, the size of the evaporation system can be reduced.

The canister 300 (first and second adsorption chambers 301 and 302), the solenoid valve 100 and the filter 310
The second space 30 which forms an air cleaner box in which is stored
6 is integrated with the canister casing 305, so that piping for connecting these 300, 100, and 306 can be eliminated. Therefore, the number of piping connections in the evaporative system can be reduced, so that the airtightness (reliability) of the evaporative system can be improved.

The canister 300 and the solenoid valve 10
0 can be eliminated, so that the solenoid valve 100 can be connected to the fuel tank 200 via the canister 300.
Can reduce the ventilation resistance of the passage leading to the path. Therefore, when refueling the fuel tank 200, the fuel tank 2
Since the air in 00 can be quickly discharged to the atmosphere side, the fuel can be quickly supplied to the fuel tank 200.

Further, since the solenoid valve 100 is disposed in the first space 304 covered by the canister casing 105, the structure is such that metal parts such as the yoke 113 are not directly exposed to the atmosphere. Therefore, the corrosion resistance of the metal parts such as the yoke 113 can be improved, and the reliability (durability) of the solenoid valve 100 can be improved.

Since the second space 306 in which the filter 310 is provided is formed to extend in a direction parallel to the direction in which the first adsorption chamber 301 extends, the canister casing 3
Without increasing the size of 05, a filtration area of effectively utilizing the elongated dimension L ₁ filter 310 can be easily increased. Also, since each port 307a to 307c is open in the same direction (direction), each port 3
Workability at the time of connecting a pipe to 07a to 307c can be improved. Therefore, it is possible to improve the mountability (assembly) of the evaporation system to the vehicle.

(Second Embodiment) In the above embodiment, both the air discharged from the canister 300 and the air sucked into the canister 300 are connected to the atmosphere port 3.
However, in the present embodiment, the suction port is provided from the atmosphere port 307c, and the discharge is mainly performed from the discharge port 311 by providing the discharge port 311 for discharge.

That is, as shown in FIGS. 4 and 5, a discharge port 311 for communicating the first space 304 with the atmosphere without the second space 306 is provided in the third lid 305d. A check valve 312 that prevents air from flowing into the first space 304 and allows air to flow from the first space 304 to the atmosphere via the discharge port 311 is provided in the third lid 305d. Set up.

Further, the ventilation resistance of the passage from the first space 304 to the atmosphere through the second space 306 is made larger than the ventilation resistance of the passage from the first space 304 to the atmosphere through the discharge port 311. As a result, when the purge state or the pressure in the fuel tank 200 decreases and air is sucked into the canister 300, the check valve 312 closes, so that air is sucked from the atmosphere port 307c. On the other hand, when the air is discharged from the canister 300, the air is mainly discharged from the discharge port 311 having a small ventilation resistance.

Therefore, at the time of inhaling air, the air from which foreign matter has been removed by the filter 310 can be supplied to the engine 220. On the other hand, at the time of discharging air, the discharge port 311
The air can be discharged more quickly. (Third Embodiment) In this embodiment, as shown in FIGS. 6 and 7, a pressure sensor 240 is disposed in a first space 304. Incidentally, in the present embodiment, the pressure sensor 240
Are fixed to the solenoid valve 100.

As a result, the pressure sensor 240 is not directly exposed to the atmosphere, and a foreign object does not directly collide with the pressure sensor 240. Therefore, the pressure sensor 240 can be protected. In addition, since air from which foreign matter and the like have been removed by the filter 310 flows into the first space 304, it is possible to prevent foreign matter and the like from entering the pressure sensor 240, and the reliability (durability) of the pressure sensor 240 is improved. Can be improved.

FIG. 6 shows an example in which the pressure sensor 240 is incorporated in the canister casing 305 in the evaporative system according to the first embodiment, and FIG. 7 shows an example in which the pressure sensor 240 is provided in the canister in the evaporative system according to the second embodiment. This is an example in which it is built in a casing 305. By the way, in the above-described embodiment, each of the ports 307a to 307
c is all directed downward, but the present invention is not limited to this, and any of the ports 307a to 307c may be oriented in other directions.

In the above-described embodiment, the first space 30
4 is covered by the canister casing 305, but the present invention is not limited to this.
May be directly exposed to the atmosphere. Further, in the above-described embodiment, the second space 306 is formed, for example, on the lower side of the sheet of FIG. 2, but the present invention is not limited to this, and the second space 306 extends in the extension direction of the first suction chamber 301. Any other portion may be used as long as it is formed to extend in a direction parallel to.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of an evaporation system.

FIG. 2A is a front view of the canister according to the first embodiment, and FIG. 2B is a side view of FIG.

FIG. 3 is a schematic view of a canister.

FIG. 4A is a front view of a canister according to a second embodiment, and FIG. 4B is a side view of FIG.

FIG. 5 is a sectional view taken along line AA of FIG. 4;

FIG. 6A is a front view of a canister according to a third embodiment, and FIG. 6B is a side view of FIG.

FIG. 7A is a front view of a canister according to a third embodiment, and FIG. 7B is a side view of FIG.

[Explanation of symbols]

300 canister, 301 first suction chamber, 302 second suction chamber, 304 first space, 306 second space, 30
5: canister casing, 307a: introduction port (tank port), 307b: purge port, 307c: atmosphere port.

Claims (4)

[Claims] 1. A fuel tank (20) for an internal combustion engine (220).
0) An evaporative fuel discharge prevention device for preventing evaporative fuel in the fuel tank (200) from being released into the atmosphere, comprising a canister casing (307) having an inlet port (307a) for introducing the evaporative fuel from the fuel tank (200). 305), a first adsorption chamber (301) provided in the canister casing (305) and adsorbing the evaporated fuel introduced from the introduction port (307a), and a first adsorption chamber (301) in the canister casing (305). One suction chamber (301) is provided in parallel with the first suction chamber (3).
01) to adsorb the evaporated fuel desorbed from the second adsorption chamber (3).
02), and an electromagnetic valve (100) that communicates with the second adsorption chamber (302) and that introduces air into the second adsorption chamber (302) or prohibits the introduction of air. The length (L ₂ ) of the second suction chamber (302) extending toward the port (307a) is increased by the length of the first suction chamber (30) extending toward the introduction port (307a).
1) By making the length (L ₁ ) smaller than the length (L ₁ ), a first space (304) is formed on the introduction port (307a) side of the second adsorption chamber (302), and the first space (304) is formed. 304) An evaporative fuel emission prevention device, wherein the solenoid valve (100) is arranged in 304). 2. The first space (304) includes the second space (304).
Pressure detecting means (2) for detecting the pressure in the suction chamber (302).
40) and the first space (30).
The evaporative fuel discharge prevention device according to claim 1, wherein 4) is covered with the canister casing (305). 3. A second suction chamber provided in parallel with the first suction chamber (301) and the second suction chamber (302) and provided in the canister casing (305).
A space (306), the second space (306) communicates with the first space (304), and an air port (307c) provided in the canister casing (305) and communicates with the atmosphere, Space (3
06), a filter (31) for preventing foreign matter from entering.
3. The evaporative fuel discharge device according to claim 2, wherein 0) is provided. 4. A purge port (307b) communicating with an intake pipe (230) of the internal combustion engine (220), an atmosphere port (307c) communicating with atmosphere, and the inlet port in the canister casing (305). (307a), the purge port (307b) and the atmosphere port (30
2. The device according to claim 1, wherein the inlet port (307 a) and the inlet port (307 a) are open in the same direction. 3.