JP2003239813A - Fuel evaporative gas emission control system for automobile - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce valve operating noise and suppress fuel evaporative gas exhausted from an atmospheric opening of a valve and canister. <P>SOLUTION: A relative pressure type two-way valve 24 composed of a negative pressure valve opening and closing a passage 23 by a relative pressure to the atmospheric pressure introduced from the atmospheric opening and a positive pressure valve comprising a diaphragm is interposed in an intermediate part of the passage 23 communicating a fuel tank 21 with a canister 22. It is composed so that when an internal pressure of the fuel tank reaches a set positive pressure or more, the positive pressure valve is opened and an evaporative emission passage to the canister is opened, and when the internal pressure reaches a specific negative pressure or lower, the negative pressure valve is opened and the evaporative emission passage is changed. A vent line 53 communicating the atmospheric opening of the valve 24 with the canister is provided so that the fuel evaporative gas permeating through the valve 24 is introduced into the canister by the vent line. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle fuel vapor emission control device, and more specifically, a fuel for suppressing fuel vapor emission gas emitted from the fuel storage and supply system of a vehicle to the atmosphere. The present invention relates to an evaporative emission control device.

[0002]

Conventionally, an automobile is provided with a fuel evaporative emission device for suppressing and reducing fuel evaporative emission (gasoline vapor) emitted from the fuel storage and supply system to the atmosphere. ing. According to such a fuel evaporative emission device 1, as shown in FIG. 4, when the fuel evaporative emission GV (indicated by a black arrow in the figure) generated in the fuel tank 2 reaches the set pressure, the evaporation conduit 3 Provided in 2
The positive pressure valve composed of the diaphragm of the way valve 4 is opened to flow into the canister 5, and HC (hydrocarbon) is temporarily adsorbed by the activated carbon 6 filled in the canister 5. Then, the HC of the fuel vaporized gas GV stored in the canister 5 is controlled by the ECU (not shown) in which the purge control valve (or check valve) 8 of the purge pipe line 7 is not shown.
When the duty is controlled by the signal from the engine or the throttle is opened by the negative pressure of the throttle, it is released from the activated carbon 6 by the atmosphere IA (shown by a white arrow in the figure) drawn from the atmosphere port 9 of the canister 5 and the engine 10 Intake system, for example intake manifold 1
1 is introduced into the combustion chamber and then sucked into the combustion chamber,
Release of HC to the atmosphere is suppressed.

By the way, a two-way valve 4 provided in the evaporative pipeline 3 of such a fuel evaporative emission control device 1.
In some cases, a relative pressure type two-way valve that opens and closes at a relative pressure with respect to the atmospheric pressure may be adopted. Such a two-way valve 4 opens when the internal pressure of the fuel tank 2 becomes a positive pressure equal to or higher than a preset value, and the diaphragm 12 that causes the fuel vaporized gas GV to flow to the canister 5 side, and when the internal pressure of the fuel tank 2 becomes a negative pressure higher than a predetermined value. A negative pressure valve 13 for switching the evaporation pipe 3 is provided, but an operating sound at the time of valve opening / closing operation may be transmitted from the negative pressure valve 13, and the operating sound causes the body frame to resonate. However, there is a problem that it may cause abnormal noise in the vehicle. Further, from the negative pressure valve 13 of the 2-way valve 4, the fuel vaporized gas GV that has passed through the diaphragm 12 in the 2-way valve 4 may be discharged from the 2-way valve 4 toward the atmosphere. Further, the fuel vapor gas GV sent into the canister 5 may be blown out from the atmospheric port 9 of the canister 5.

Therefore, the present invention has been made in order to solve the problems of the above-described conventional device for suppressing the evaporative emission of fuel vapor from an automobile, and it is a relative pressure system 2.
In addition to reducing the valve operating noise transmitted from the atmospheric opening of the way valve, it is possible to suppress the fuel evaporative emission gas discharged into the atmosphere from the atmospheric opening of each of the relative pressure type two-way valve and the canister. An object of the present invention is to provide a vehicle fuel vapor emission suppressing device that can be used.

[0005]

In order to achieve the above object, according to claim 1, an atmospheric pressure introduced from an atmospheric opening to an intermediate portion of an evaporative conduit communicating a fuel tank and a canister. There is provided a relative pressure type two-way valve composed of a negative pressure valve for opening and closing the evaporation pipe line by a relative pressure between the two and a relative pressure type two-way valve, and the relative pressure type two-way valve is an internal pressure of the fuel tank. When the internal pressure of the fuel tank becomes a negative pressure higher than a specified value, a negative pressure valve opens to switch the evaporation line when the internal pressure of the fuel tank becomes negative. In the fuel vapor evaporative emission control device for an automobile, the relative pressure type two-way valve is provided with a ventilation pipe line that connects the atmospheric opening of the relative pressure type two-way valve and the canister. It is characterized by being introduced into the canister fuel vapor that has passed through the diaphragm inner by the vent line.

According to a second aspect of the present invention, in the canister according to the first aspect, an atmospheric port for introducing the atmospheric air is formed inside the canister, and an air filter for filtering the atmospheric air is connected to the atmospheric port. It is characterized by that.

According to a third aspect of the present invention, the canister according to the first aspect includes an air port for introducing air into the canister and an air filter for filtering the air introduced from the air port. It is characterized by being.

A fourth aspect of the present invention is characterized in that the air filter according to the second or third aspect is provided with a filter paper sheet in which activated carbon and a non-woven fabric are laminated.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, an embodiment of an automobile fuel evaporative emission control device of the present invention will be described with reference to FIGS. FIG. 1 is a configuration diagram for explaining a fuel vapor emission suppressing device for an automobile of the present invention, and FIG. 2 is a sectional view taken along the line AA in FIG. 1 for explaining an air filter provided in the same example. It is a figure.

First, the fuel evaporative emission control device 20 of the present invention is applied to, as shown in FIG. 1, an evaporation conduit 23 for connecting a fuel tank 21 and a canister 22.
In the middle part of the
A relative pressure type two-way valve (hereinafter referred to as a two-way valve) 24 that opens and closes the fuel tank is provided. When the internal pressure of the fuel tank 21 becomes a positive pressure equal to or higher than a preset value, the two-way valve 24 is an evaporation pipe for the canister 22. Open road 23,
When the internal pressure of the fuel tank 21 becomes a negative pressure equal to or higher than a specified value, the negative pressure valve of the two-way valve 24 opens to switch the evaporation conduit 23 and introduce the atmosphere IA into the fuel tank 21. .

The fuel tank 21 will be described. The fuel tank 21 is suspended by a fixed band on the vehicle body below the rear seat, and the tank bottom is formed in a saddle shape so as to straddle the rear differential device under the fuel tank 21. At the upper end of the filler pipe 25 connected to guide the fuel into the fuel tank 21,
A filler cap 26 for closing the fuel refueling port is mounted, and a shut valve 27 for closing the evaporation conduit 23 during refueling is incorporated in order to prevent over refueling.

Further, at the upper end of the filler pipe 25,
One end of the pressure difference detection conduit 28 is connected, and the other end of the pressure difference detection conduit 28 is connected to the fuel tank 2
1 is connected to a vent valve 29 mounted above. The vent valve 29 opens and closes the vent pipe line 30 that connects the upper space (the air chamber portion) in the fuel tank 21 and the canister 22 in accordance with the pressure difference between the internal pressure of the fuel tank 21 and the atmospheric pressure. It is configured. Therefore, when the inner pressure of the fuel tank 21 and the atmospheric pressure have a predetermined pressure difference when the filler cap 26 is removed due to fuel refueling or the like, the vent valve 29 opens the vent pipe line 30 to cause the fuel to open. The fuel vaporized gas GV in the tank 21 is sent to the canister 22. This suppresses atmospheric release of the fuel vaporized gas GV from the fuel filler port, and
Air is evacuated from the fuel tank 21 when refueling.
The vent valve 29 is provided with a float 31 that floats up and down together with the liquid level in the fuel tank 21. The float 31 moves up to close an air hole (not shown) of the vent valve 29, and Road 30
The inflow of fuel (liquid content) into the tank is prevented.

Further, above the inside of the fuel tank 21, an evaporation conduit 2 for connecting the fuel tank 21 and the canister 22 is formed.
3 is connected and piped with one end thereof branched. The evaporation conduit 23 introduces the fuel vaporized gas GV in the fuel tank 21 having a positive pressure equal to or higher than a set value into the canister 22 or the internal pressure of the fuel tank 21 is a negative pressure equal to or higher than a predetermined value regardless of the engine operating state. When the pressure is reached, it is used when introducing the atmospheric air IA into the fuel tank 21. Then, at the branched pipe end portion of the evaporation pipe 23, the float 3 that floats up and down together with the liquid level in the fuel tank 21 to prevent the fuel (liquid component) from flowing into the evaporation pipe 23.
A fuel shut-off valve 34 and a fuel shut-off sub-valve 35 provided with Nos. 2 and 33 are attached with a height difference. A two-way valve 24 that opens and closes the evaporation conduit 23 is provided in the middle of the evaporation conduit 23, and the evaporation conduit 2 is
The other end of 3 is connected to the middle part of the vent pipe line 30.

Further, a pressure sensor 36 for detecting the internal pressure of the fuel tank 21 and outputting it to a control means (ECU) (not shown) is attached at a position communicating with the upper air chamber of the fuel tank 21.

Next, the canister 22 will be described.
The canister 22 has a tank port 37 to which the other end of the vent line 30 is connected, and activated carbon 38 which is internally filled so as to temporarily adsorb HC of the fuel vaporized gas GV introduced from the tank port 37. , An atmosphere port 39 for introducing the atmosphere IA into the canister 22 in order to separate the HC adsorbed on the activated carbon 38, and a purge for introducing the atmosphere IA containing the fuel vaporized gas GV and HC into the intake manifold 41 of the engine 40. A purge port 43 to which one end of the pipe line 42 is connected, and a ventilation port 44 through which the fuel vaporized gas GV introduced into the canister 22 and the atmosphere IA are ventilated are provided.

Further, an air filter 45 and a drain valve 46 are connected in series to the atmosphere port 39. The air filter 45, as shown in FIG.
Gas that passes through and circulates inside the canister 2, for example
The total flow rate of the atmospheric air IA and the like introduced into 2 is a full flow type that passes through the filter element 47. The filter element 47 is formed by folding a filter paper 50, in which both side surfaces (inner and outer peripheral surfaces in FIG. 2) of the activated carbon layer 48, which is the center layer, are covered with a nonwoven fabric 49 into a star shape. The effective filtration area of is sufficiently secured. The filter paper 50 may be pleated along the longitudinal direction of the filter element 47. The drain valve 46 is interposed between the atmosphere port 42 and the air filter 45, and is opened / closed by the control means to control the flow rate of the passing gas. Reference numeral 51 in the figure denotes a purge control valve (or a check valve) that is opened / closed by a control unit according to the engine operating state. By the way, the ventilation port 44 of the canister 22 is connected to one end of a ventilation conduit 53 that communicates with the atmospheric port 52 of the two-way valve 24.

The two-way valve 24 will be described. The two-way valve 24 opens and closes the evaporation conduit 23 by the relative pressure between the atmospheric port 52 to which the other end of the ventilation conduit 53 is connected and the atmospheric pressure introduced into the interior from the atmospheric port 52. And a diaphragm 54. The two-way valve 24 causes the fuel tank 21 and the canister 22 to communicate with each other by the fuel vaporized gas GV pushing up the diaphragm 54 when the internal pressure of the fuel tank 21 becomes a positive pressure equal to or higher than a set value, regardless of the engine operating state. Is configured to. Further, when the internal pressure of the fuel tank 21 becomes a negative pressure equal to or higher than a specified value, the diaphragm 54 closes the evaporation conduit 23, and the negative pressure valve of the diaphragm 54 opens.

Therefore, according to the fuel evaporative emission control device 20 of the present invention, the radiant heat from the moving vehicle or the road, the vehicle temperature when the engine is stopped immediately after the traveling, the outside temperature when the vehicle is parked for a long time, etc. As the heat source, when the fuel vaporized gas GV generated in the fuel tank 21 reaches the set pressure, the drain valve 46 is controlled to be opened by the control means and the diaphragm of the two-way valve 24 provided in the evaporation conduit 23. 52 is pushed up and begins to flow toward the canister 22. At this time, since the atmosphere port 52 of the two-way valve 24 is communicated with the canister 22 by the ventilation pipe line 53, the operating sound at the valve opening operation does not pass through the atmosphere port 52. And canister 2
The fuel evaporative gas GV flowing out toward the second side is introduced into the canister 22 from the tank port 37 after passing through the vent pipe 30, and HC of the fuel evaporative gas GV is temporarily adsorbed by the activated carbon 38. . The fuel vaporized gas GV (air component) from which HC has been separated is returned to the atmospheric port 39.
Is discharged toward the air filter 45 through the drain valve 46, and HC is carefully removed by the activated carbon layer 48 of the filter element 47 so that even a trace amount of HC does not leak to the atmosphere when passing through the air filter 45. . As a result, the HC of the fuel vaporized gas GV sent into the canister 22 is prevented from blowing through the atmospheric port 39 of the canister 22.

With respect to the HC of the fuel vaporized gas GV adsorbed on the activated carbon 38 in the canister 22, the control means opens the purge control valve 51 and the drain valve 46 in accordance with the engine operating state. It is separated from the activated carbon 38 by the atmospheric air IA introduced into the canister 22. Then, the separated HC of the fuel evaporative gas GV is sent to the intake manifold 41 from the purge line 42 together with the introduced atmosphere IA, and then is sucked into the combustion chamber of the engine 40 by the intake manifold negative pressure and then burned. To be done.

On the other hand, when the temperature of the fuel in the fuel tank 21 decreases with the lapse of time after the engine is stopped, the fuel vaporized gas GV in the fuel tank 21 is liquefied and the fuel volume is contracted, and the inside of the fuel tank 21 is positively pressurized. Starts to change to negative pressure. Then, when the internal pressure of the fuel tank 21 becomes a negative pressure equal to or higher than the specified value, the control means controls the drain valve 46 to open based on the detection value of the internal pressure sensor 36. Then, the air IA filtered by the air filter 45 is introduced into the canister 22 from the air port 39, and the canister 2
It is introduced from the two ventilation ports 44 to the atmospheric port 52 of the two-way valve 24. Then, the diaphragm 54 of the 2-way valve 24 closes the evaporation conduit 23 and the negative pressure valve opens. Then, the atmospheric air IA and the like introduced into the canister 22 is sucked into the fuel tank 21 whose inside has a negative pressure through the vent pipe line 30. This prevents the fuel tank 21 from being deformed, and
Since the atmosphere port 52 of the way valve 24 and the canister 22 are communicated with each other by the ventilation conduit 53, the operating sound at the time of valve closing operation does not pass through the atmosphere port 52. Then, when the internal pressure of the fuel tank 21 that has sucked in the air IA or the like falls within a specified value, the drain valve 46 is controlled to be closed and the suction of the air IA or the like into the fuel tank 21 is stopped.

As a result, it is possible to suppress the HC of the fuel evaporative gas GV emitted from the fuel storage and supply system of the automobile to the atmosphere, and it is possible to preserve the environment by reducing the emission amount.

In this embodiment, an air filter 45 and a drain valve 46 are attached to the atmospheric port 39 of the canister 22.
3 and 4 are connected in series, but as shown in FIG. 3, the air filter 45 ′ and the drain valve 46 ′, which have substantially the same filtering performance as the air filter 45, are incorporated in the canister 22 to be integrated. You may comprise. As a result, in addition to the effects and advantages substantially similar to those of the above-described embodiment, they can be easily mounted even in a vehicle in which a space for arranging the air filter 45 and the drain valve 46 cannot be secured, and the efficiency of mounting work is improved. It can also be achieved.

[0023]

As described above, according to the fuel vapor emission suppressing device for an automobile of the present invention, not only the operating noise of the valve transmitted through the atmospheric port of the relative pressure type two-way valve can be reduced, but also the noise can be reduced. It is possible to provide a fuel evaporative emission control device for an automobile capable of suppressing the fuel evaporative emission discharged into the atmosphere from the respective atmospheric openings of the relative pressure type two-way valve and the canister.

[Brief description of drawings]

FIG. 1 is a configuration diagram for explaining a fuel evaporative emission control device for an automobile according to the present invention.

FIG. 2 is a cross-sectional view taken along the line AA in FIG. 1 for explaining the air filter included in the same example.

FIG. 3 is a configuration diagram for explaining a fuel evaporative emission control device for an automobile, which is different from the example.

FIG. 4 is a configuration diagram illustrating a conventional fuel vapor emission suppressing device for an automobile.

[Explanation of symbols]

20 Evaporative emission control device for fuel 21 Fuel tank 22 canister 23 Evaporative pipeline 24 Relative pressure 2-way valve 39 Atmospheric port (of canister) 45,45 'air filter 48 Activated carbon bed 49 Nonwoven 50 filter paper 52 Atmosphere port (2-way valve) 53 Vent pipe GV fuel evaporative gas (gasoline vapor) IA atmosphere (intake air)

Continued front page    (72) Inventor Masayuki Suzuki             1-7-2 Nishi-Shinjuku, Shinjuku-ku, Tokyo Fuji             Heavy Industry Co., Ltd. (72) Inventor Tatsuo Yoshida             1-7-2 Nishi-Shinjuku, Shinjuku-ku, Tokyo Fuji             Heavy Industry Co., Ltd. F-term (reference) 3G044 BA28 BA32 GA03 GA16 GA23                       GA24

Claims (4)

[Claims] 1. A positive pressure valve comprising a negative pressure valve and a diaphragm for opening and closing the evaporative pipeline by a relative pressure with an atmospheric pressure introduced from an atmospheric opening in an intermediate portion of the evaporative pipeline communicating with the fuel tank and the canister. A relative pressure type two-way valve composed of a pressure valve is interposed, and the positive pressure valve opens in the relative pressure type two-way valve when the internal pressure of the fuel tank becomes a positive pressure equal to or higher than a preset value, and an evaporation conduit to the canister. In the fuel vapor emission restraint system for a vehicle, which is configured to open the negative pressure valve and switch the evaporative pipeline when the internal pressure of the fuel tank becomes a negative pressure equal to or higher than a predetermined value,
A vent pipe is provided which connects the atmospheric opening of the relative pressure type two-way valve and the canister, and the fuel evaporative gas passing through the diaphragm in the relative pressure type two-way valve is introduced into the canister by the vent line. A vehicle evaporative emission control device for automobiles. 2. The automobile according to claim 1, wherein the canister has an atmospheric port for introducing atmospheric air into the canister, and an air filter for filtering atmospheric air is connected to the atmospheric port. Fuel evaporative emission control device. 3. The canister comprises an atmospheric port for introducing atmospheric air into the canister, and an air filter for filtering the atmospheric air introduced from the atmospheric port. A vehicle fuel vapor emission device as described. 4. The fuel evaporative emission control device for an automobile according to claim 2, wherein the air filter comprises a filter paper sheet in which activated carbon and non-woven fabric are laminated.