JPH08232780A - Evaporated fuel controller for internal combustion engine - Google Patents

Abstract

PURPOSE: To make it impossible to supply fuel to a fuel tank during operation of an internal combustion engine as well as possible to prevent the evaporated fuel from being discharged into the atmosphere during fuel supply to the fuel tank, in the case of the evaporated fuel controller. CONSTITUTION: A communication passage 88 for providing communication between a fuel tank and a canister provided in addition to an evaporation passage and a control valve 92 is provided on the way of the communication passage 88. The housing 94 of the valve is divided into 2 pieces by means of a bulkhead 96, and a valve body 116 for opening/closing the communication passage 88 in the fourth chamber by being fixed to the second diaphragm is provided on a piston 112 for coupling, through the bulkhead, the first diaphragm 102 whose one side is formed in the first and second chamber 98, 100, with the second diaphragm 108 formed in the third, fourth chambers 104, 106. The second spring 120 of the second diaphragm is made stronger than the first spring 118, a passage 122 for guiding the atmosphere to the first chamber is provided, a negative pressure passage 124 for guiding intake pipe negative pressure staying in the intake air passage to the second chamber is provided, and a tank passage 126 is provided for communicating the third chamber with the upper of the fuel tank.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an evaporative fuel control system for an internal combustion engine, and more particularly to preventing the evaporative fuel from being released to the atmosphere during refueling of a fuel tank, The present invention relates to an evaporated fuel control device for an internal combustion engine that can ensure safety by preventing refueling of a tank.

[0002]

2. Description of the Related Art In vehicles, evaporated fuel leaking from a fuel tank or the like into the atmosphere contains a large amount of hydrocarbons (HC) and is one of the causes of air pollution, and also leads to loss of fuel. Therefore, various techniques for preventing this are known. As a typical example thereof, there is an evaporative fuel control device (evaporation system) in which a canister containing an adsorbent such as activated carbon separates (purges) the evaporated fuel in a fuel tank during operation of the internal combustion engine and supplies the evaporated fuel to the internal combustion engine.

In this evaporative fuel control system, as shown in FIG. 9, the evaporation passage 2 communicating with the inside of the fuel tank 202.
04 and a purge passage 212 communicating with an intake passage 210 on the downstream side of the throttle valve 208 in the intake system of the internal combustion engine 206, which is generated in the fuel tank 202 while the internal combustion engine 206 is stopped and is guided to the evaporation passage 204. A canister 216 is provided which adsorbs and holds the evaporated fuel that has been adsorbed and holds the evaporated fuel that has been adsorbed and held by the atmosphere introduced from the atmosphere communication passage 214 and supplies it to the intake passage 210 from the purge passage 212 during operation of the internal combustion engine 206. There is. Purge passage 21
A purge valve (2-way solenoid valve) 218 that controls the amount of evaporated fuel to the intake passage 210 according to the operating state of the internal combustion engine 206 is provided in the middle of 2. The purge valve 218 is duty-controlled by a control unit (ECM) (not shown) to be opened / closed.

Further, the fuel tank 202 has a refueling gun 2
An oil supply pipe 222 for injecting fuel from 20 is provided. Further, the fuel tank 202 includes the fuel tank 20
A breather pipe 224 is provided to connect the upper portion of the fuel tank 2 and the middle of the oil supply pipe 222.

Such an evaporated fuel control device is disclosed in, for example, Japanese Patent Laid-Open No. 60-199727. In the fuel tank for a vehicle described in this publication, a removable cap is attached to a fuel inlet of a fuel tank, and the cap is covered by an opening / closing lid for a fuel filler port pivotally attached to a vehicle body. By providing an open / close control valve in the vaporized fuel passage that connects the inside of the fuel tank and the canister, the open / close control valve that is opened when the open / close lid is opened is connected to the vaporized fuel in the fuel tank when the open / close lid is opened. To the canister, and the fuel vapor that is generated in the fuel tank during fuel refueling is also sent to the canister, so when the fuel inlet cap is removed and during fuel refueling, it leaks to the outside air from the fuel inlet. The amount of fuel vapor is reduced, and air pollution due to the outflow of fuel vapor is suppressed.

[0006]

However, in the fuel vapor control apparatus shown in FIG. 9, the fuel vapor generated in the fuel tank is released from the breather pipe to the atmosphere during refueling when fuel is injected into the fuel tank. However, there is an inconvenience of causing air pollution.

Further, in the fuel vapor control system described in the above publication, the on-off control valve may be activated during operation of the internal combustion engine. Therefore, the fuel consumption during operation of the internal combustion engine such as during idling It may be possible to refuel the tank, which may be dangerous.

[0008]

Therefore, in order to eliminate the above-mentioned inconvenience, the present invention is provided between an evaporation passage communicating with the inside of a fuel tank and a purge passage communicating with an intake passage of an intake system of an internal combustion engine. The evaporated fuel that is generated in the fuel tank when the internal combustion engine is stopped and is guided to the evaporation passage is adsorbed and held, and the evaporated fuel that is adsorbed and held by the atmosphere introduced from the atmosphere communication passage while the internal combustion engine is operating. And a purge valve for controlling the amount of evaporated fuel to the intake passage in accordance with the operating state of the internal combustion engine. In an evaporated fuel control device for an engine, a communication passage that connects the fuel tank and the canister is provided, and a control valve is provided midway in the communication passage. The in the valve housing of the roll valve 2
A partition wall to be divided is provided, and a first partition in the valve housing is provided between one side of the partition wall and one side of the valve housing.
A first diaphragm that forms a second chamber is provided, and a second diaphragm that forms third and fourth chambers in the valve housing is provided between the other side of the partition wall and the other side of the valve housing. A piston that penetrates through the partition wall is provided so as to connect the diaphragm and the second diaphragm, and the piston is provided with a valve body that is fixed to the second diaphragm and that opens and closes the communication passage in the fourth chamber.
A first spring that applies a predetermined biasing force to the first diaphragm is provided in the second chamber between the partition wall and the first diaphragm, and the third chamber is provided in the third chamber between the partition wall and the second diaphragm. The second diaphragm is provided with a second spring that exerts a stronger biasing force than the biasing force of the first spring, an atmosphere passage for guiding the atmosphere to the first chamber, and a suction pipe negative pressure of the intake passage in the second chamber. Is provided, and a tank passage that connects the third chamber and the upper portion of the fuel tank is provided.

[0009]

According to the structure of the present invention, when the internal combustion engine is stopped, the urging force of the second spring is stronger than the urging force of the first spring in the control valve, so that the control valve closes to close the communication passage. In addition, when refueling the fuel tank, the control valve opens due to the tank internal pressure of the fuel tank to open the communication passage, so the evaporated fuel in the fuel tank flows to the canister side and is collected in the canister. Further, when the internal combustion engine is operating, the control valve is strongly closed by the negative pressure of the intake pipe to close the communication passage. As a result, the evaporated fuel generated in the fuel tank when the internal combustion engine is stopped is collected in the canister to prevent the evaporated fuel from being released to the atmosphere, and when the fuel tank is refueled, it is generated in the fuel tank. The vaporized fuel is collected in the canister to prevent the vaporized fuel from being released to the atmosphere, thereby preventing air pollution, and further, when the internal pressure of the fuel tank increases during operation of the internal combustion engine, the communication passage It is possible to ensure safety by securely closing the fuel tank so that fuel cannot be supplied to the fuel tank.

[0010]

Embodiments of the present invention will be described in detail and specifically with reference to the drawings. 1 to 8 show an embodiment of the present invention. In FIG. 1, 2 is an internal combustion engine, 4 is an intake manifold, 6 is an intake passage, 8 is a surge tank, 1
0 is a throttle valve, 12 is a fuel injection valve, 14 is an air cleaner,
16 is a fuel tank. An oil supply pipe 20 provided with an oil supply cap 18 is connected to the fuel tank 16. Further, the fuel pump 16 and the first
A float valve 24, a second float valve 26, and a level gauge 28 that detects the amount of fuel are provided. Fuel pump 2
The fuel supply passage 30 is provided at 2 with one end thereof connected thereto. The other end of the fuel supply passage 30 is provided so as to communicate with the fuel injection valve 12. A fuel pressure regulator 32 is connected to the fuel injection valve 12. One end side of a fuel return passage 34 is provided in communication with the fuel pressure regulator 32. The other end side of the fuel return passage 34 is provided so as to open in the fuel tank 16.

An evaporated fuel control device (evaporation system) 36 is provided between the fuel tank 16 and the intake system of the internal combustion engine 2.

In the evaporated fuel control device 36, the other end side of the evaporation passage 38 having one end communicating with the inside of the fuel tank 16 and the other end side of the purge passage 40 having one end communicating with the surge tank 8 constituting the intake passage 6 are connected. A canister 42 is provided between and. One end of the evaporation passage 38 is
In the fuel tank 16, it is provided in communication with the inside of the float guide body 44 so as to be opened and closed by the first float valve 24 which is guided in the first float guide body 44 and moves up and down. The other end side of the evaporation passage 38 and the other end side of the purge passage 40 are juxtaposed in the upper portion of the canister 42 and open. In addition, the canister 42 has an atmosphere communication passage 4
One end side of 6 is provided in communication. An air cut valve (2-way solenoid valve) 48 for opening and closing the atmosphere communication passage 46 is provided on the other end side of the atmosphere communication passage 46. The air cut valve 48 is operated to be opened and closed by a control unit 84 described later.

The canister 42 adsorbs and holds the vaporized fuel generated in the fuel tank 16 while the internal combustion engine 2 is stopped and introduced into the evaporation passage 38, and also from the atmosphere communication passage 46 during operation of the internal combustion engine 2. The evaporated fuel adsorbed and held by the introduced air is separated and supplied from the purge passage 40 to the intake passage 6.

As shown in FIG. 4, the air cut valve 48 comprises an air cut solenoid 50 and an air cut valve body 52 that reciprocates so as to open and close the atmosphere communication passage 46.

In the middle of the evaporation passage 38, the fuel tank 1
The pressure sensor 56 is sequentially opened from the 6th side through the detection pressure passage 54, and the evaporation passage 38 is opened so that the evaporation passage 38 is opened when the tank internal pressure of the fuel tank 16 reaches a predetermined set pressure while the internal combustion engine 2 is stopped. Tank internal pressure control valve (TPCV) 5
8 are provided. The pressure sensor 56 detects the tank internal pressure of the fuel tank 16.

As shown in FIG. 3, the tank internal pressure control valve 58 has a pressure acting chamber 64 and a passage communication chamber 66 which are divided and formed by a tank internal pressure control diaphragm 62 provided in a tank internal pressure control housing 60. are doing. In the pressure action chamber 64, the tank internal pressure control spring 6 that applies a predetermined biasing force to the tank internal pressure control diaphragm 62.
8 are provided. The passage communication chamber 66 is provided with a valve seat body 70 that opens and closes the evaporation passage 38 by contact and separation of the tank internal pressure control diaphragm 62.

The tank pressure control valve 58 is also opened / closed by the control means 72 so as to open / close the evaporation passage 38 during the operation of the internal combustion engine 2. That is, one end side of the pressure passage 74 is provided in communication with the pressure action chamber 64 of the in-tank pressure control valve 58. The other end of the pressure passage 74 is provided in communication with the surge tank 8.
A pressure adjusting valve (3 way solenoid valve) 76 is provided in the middle of the pressure passage 74.

This pressure adjusting valve 76, as shown in FIG.
A pressure adjusting solenoid 78, and a pressure adjusting valve body 82 that reciprocates to allow the introduction of the atmosphere from the atmosphere port 80 when the pressure passage 74 is opened and closed and the surge tank 78 side of the pressure passage 74 is closed. Consists of. This pressure regulating valve 7
6 is switched (on / off operated) by duty control by the control unit (ECM) 84 to act the atmosphere from the pressure passage 74 to the pressure action chamber 64 of the tank internal pressure control valve 58, or to control the tank internal pressure. The intake pipe negative pressure in the surge tank 8 is applied from the pressure passage 74 to the pressure action chamber 64 of the valve 58.

In the middle of the purge passage 40, a purge valve 86 for controlling the amount of evaporated fuel to the intake passage 6 according to the operating state of the internal combustion engine 2 is provided. The purge valve 86 is
It has the same structure as the air cut valve 48.

In addition to the pressure adjusting valve 76, the control unit 84 is connected to the fuel injection valve 12, the level gauge 28, the air cut valve 48, the pressure sensor 56, and the purge valve 86.

The control unit 84 inputs each signal from the level gauge 28, the pressure sensor 56, etc., opens and closes the evaporation passage 38 during the operation of the internal combustion engine 2, and causes the evaporated fuel in the fuel tank 16 to pass through the canister 42. The pressure control valve 76 is switched so that the fuel is supplied to the side, the fuel injection valve 12 is operated to control the fuel supply amount to the internal combustion engine 2, and the air cut valve 48 is opened / closed to open the atmosphere communication passage. 46 is opened and closed to introduce air into the canister 42 or the canister 4
The air from 2 is discharged, and the purge valve 86 is opened / closed to open / close the purge passage 40 to control the amount of evaporated fuel to the intake passage 6.

A communication passage 88 that connects the fuel tank 16 and the canister 42 is provided between the fuel tank 16 and the canister 42. The communication passage 88 is provided in communication with the second float guide body 90 so as to be opened and closed by the second float valve 26 that is guided in the second float guide body 90 in the fuel tank 16 and moves up and down. There is.

A control valve 92 directly attached to the fuel tank 16 in relation to the second float valve 26 is provided in the communication passage 88.

The control valve 92 is constructed as shown in FIG. That is, the valve housing 94 is provided with the partition wall 96 that divides the inside of the valve housing 94 into two parts. One side of the partition wall 96 and the valve housing 9
4 between the first side and the second side in the valve housing 94.
A first diaphragm 102 that defines the chambers 98 and 100.
Is provided. The other side of the partition wall 96 and the valve housing 94
A second diaphragm 108 for partitioning and forming third and fourth chambers 104 and 106 in the valve housing 94 between the other sides.
Is provided. A piston 112 is provided in the valve housing 94 so as to connect the first diaphragm 102 and the second diaphragm 108 to the through hole 110 of the partition wall 96. The piston 112 has one end fixed to the first diaphragm 102 and the other end fixed to the second diaphragm 108 to open and close the communication passage 88 in the fourth chamber 106.
A valve body 116 is provided to contact with and separate from the valve 14. A first spring 118 that applies a predetermined biasing force to the first diaphragm 102 is provided in the second chamber 100 between the partition wall 96 and the first diaphragm 102. In the third chamber 104 between the partition wall 96 and the second diaphragm 108, the second diaphragm 108 is provided.
A second spring 120 that exerts a stronger biasing force than the biasing force of the first spring 118 is provided. First room 98
An atmosphere passage 122 for guiding the atmosphere is provided in the. In the second chamber 100, the negative pressure passage 1 for guiding the negative pressure of the intake pipe of the intake passage 6
24 are provided. A tank passage 126 is provided between the third chamber 104 and the fuel supply pipe 20 which is the upper portion of the fuel tank 16.

As a result, when the internal combustion engine 2 is stopped, the control valve 92 receives the urging force of the first spring 118 and the second force.
The communication passage 88 is closed in relation to the urging force of the spring 120, and when the fuel tank 16 is refueled, the second diaphragm 108 receives a tank internal pressure higher than the set pressure at which the tank internal pressure control valve 58 opens. By acting, the communication passage 88 is opened, and further, during operation of the internal combustion engine 2, the communication passage 88 is reliably closed by the negative pressure of the intake pipe acting on the second chamber 100. In FIG. 7, reference numeral 1
28 is a refueling gun.

Next, the operation of this embodiment will be described.

When the internal combustion engine 2 is stopped, the opening / closing operation of the tank internal pressure control valve 58 depends on the tank internal pressure of the fuel tank 16, and the pressure adjusting valve 76 introduces the atmosphere into the pressure action chamber 64 of the tank internal pressure control valve 58. As described above, the pressure passage 74 on the surge tank 8 side is closed, the air cut valve 48 is opened, and the first float valve 2 is closed.
4 has opened the evaporation passage 38. As a result, in the tank internal pressure control valve 58, the tank internal pressure control diaphragm 62 is joined to the valve seat body 70 by the urging force of the tank internal pressure control spring 68, and thus the evaporation passage 38 is formed.
Is closed. In such a case, for example, when the tank internal pressure of the fuel tank 16 reaches a predetermined set pressure, the tank internal pressure control valve 58 temporarily opens to open the evaporation passage 38, and the evaporated fuel in the fuel tank 16 is removed. While flowing to the canister 42 side and collecting it in the canister 42, the tank internal pressure of the fuel tank 16 is lowered, and only the air contained in the evaporated fuel is discharged from the atmosphere communication passage 46.

In the control valve 92 when the internal combustion engine 2 is stopped, as shown in FIG. 6, the urging force of the first spring 118 acts on the first diaphragm 102,
The urging force of the second spring 120 acts on the second diaphragm 108. In addition, the first chamber 98 has a first atmospheric pressure
The pressure P ₁ acts, and the second pressure P of the atmospheric pressure is applied to the second chamber 100.
₂ acts, the third pressure P ₃ of the tank internal pressure of the fuel tank 16 acts on the third chamber 104, the fourth pressure P ₄ of the tank internal pressure of the fuel tank 16 acts on the fourth chamber 106, and 1 pressure P ₁ = second pressure P ₂ , third pressure P ₄ = fourth pressure ₄
And the relationship of P ₁ , P ₂ <P ₃ , P ₄ .

Further, since the urging force of the second spring 120 is larger than the urging force of the first spring 118, the piston 112 moves toward the fourth chamber 106 and moves toward the valve body 116.
Is joined to the control valve seat body 114. As a result, the communication passage 88 is closed by the valve body 116.

When refueling the fuel tank 16, the tank internal pressure control valve 58 depends on the tank internal pressure of the fuel tank 16, and the pressure adjusting valve 76 causes the pressure acting chamber 64 of the tank internal pressure control valve 58 to be exposed to the atmosphere. Is turned off so that only the pressure passage 74 on the surge tank 8 side is closed, the air cut valve 48 is opened, and the first float valve 24 opens the evaporation passage 38. There is. And
As shown in FIG. 7, when fuel is injected into the refueling pipe 20 by the refueling gun 128, the tank internal pressure of the fuel tank 16 becomes higher than a predetermined set pressure, and the high tank internal pressure causes the tank internal pressure control valve 58 to open. Evaporative passage 38
As a result, the evaporated fuel generated in the fuel tank 16 flows smoothly from the evaporation passage 38 to the canister 42 side and is collected in the canister 42, and only the air contained in the evaporated fuel is connected to the atmosphere communication passage. Emitted from 46 to the atmosphere.

Further, in the control valve 92 when refueling the fuel tank 16, atmospheric pressure acts on the first chamber 98, the second chamber 100 and the third chamber 104 as shown in FIG. When the tank internal pressure of 16 becomes higher than the atmospheric pressure (for example, the tank internal pressure is about 150 〓 Ag or less), the tank pressure acts on the fourth chamber 106 so that the second diaphragm 108 resists the urging force of the second spring 120. Then, the third chamber 104 is displaced in the contracting direction, that is, the urging force of the second spring 120-the urging force of the first spring 118 <about 150 〓 Ag, which causes the valve body 116 to move from the control valve seat body 114. Separated, communication passage 88
Open up. As a result, the evaporated fuel and air in the fuel tank 16 flow from the communication passage 88 to the canister 42 side, the evaporated fuel is collected by the canister 42, and only the air contained in the evaporated fuel is cut off by the air cut valve. Since 48 is open, the air communication passage 46
Emitted from.

Then, during operation of the internal combustion engine 2, the control section 84 causes the pressure adjusting valve 76 to be turned on by duty control so that the intake pipe negative pressure acts on the pressure action chamber 64 of the tank internal pressure control valve 58. Therefore, the tank internal pressure control valve 58
Opens and closes to cause the evaporated fuel in the fuel tank 16 to flow to the canister 42 side. Further, the control unit 84 opens and closes the purge valve 86 by duty control. As a result, the atmosphere is introduced from the atmosphere communication passage 46, the evaporated fuel in the canister 42 is purged by this atmosphere, and the evaporated fuel is supplied from the purge passage 40 to the intake passage 6.

In the control valve 92 during operation of the internal combustion engine 2, as shown in FIG. 8, the intake pipe negative pressure from the intake passage 6 acts on the second chamber 100 via the negative pressure passage 124, and the third A tank passage 126 is provided in the chamber 104.
Since the tank internal pressure acts, the relationship of the second pressure P ₂ <the first pressure P ₁ , the third pressure P ₃ , and the fourth pressure P ₄ is established. Therefore, the piston 112 is urged toward the fourth chamber 108 with a stronger force than when the internal combustion engine 2 is stopped, so that an increase in the tank internal pressure of the fuel tank 16, a liquid pressure due to liquid rising, and a force due to pulsating pressure are generated. Even when acting on the second diaphragm 108, the valve body 116 is strongly joined to the control valve seat body 114, and the communication passage 88 is closed. Therefore, when the internal combustion engine 2 is in an idle operation, or the like, it is possible to make fuel supply to the fuel tank 16 impossible and ensure safety.

As a result, when the internal pressure of the fuel tank 16 becomes higher than the set value when the internal combustion engine 2 is stopped or the fuel is supplied to the fuel tank 16, the internal tank pressure control valve 58 opens to open the evaporation passage 38. Since it is opened, the evaporated fuel from the evaporation passage 38 flows toward the canister 42 side, is collected by the canister 42, and is not released to the atmosphere. Only the air contained in the evaporated fuel is released to the atmosphere. Therefore, air pollution can be prevented.

During operation of the fuel tank 16, high tank internal pressure, pulsation pressure, and hydraulic pressure are applied to the second diaphragm 108.
Even if it acts, the communication passage 88 can be reliably closed by the negative pressure of the intake pipe, so that it is impossible to refuel the fuel tank 16 and safety can be secured.

Further, the evaporated fuel control device 36 of this embodiment is
In the above, the normal evaporative control is properly performed during the operation of the internal combustion engine 2, and a regulation for preventing the evaporative fuel from being released to the atmosphere when the internal combustion engine 2 is stopped or while the fuel tank 16 is being refueled, Air cut valve 48, tank internal pressure control valve 5
8 and the valves such as the purge valve 86 can be opened and closed to deal with the regulation for checking the leakage of the evaporated fuel.

[0037]

As is apparent from the above detailed description, according to the present invention, a communication passage that connects the fuel tank and the canister is provided, a control valve is provided in the middle of the communication passage, and the inside of the valve housing of the control valve is provided. A first partition which is provided with a partition wall that divides into two parts and which forms a first chamber and a second chamber in the valve housing between one side of the partition wall and one side of the valve housing.
A diaphragm is provided, and a second diaphragm that forms third and fourth chambers in the valve housing is provided between the other side of the partition wall and the other side of the valve housing, and the partition wall connects the first diaphragm and the second diaphragm. And a valve body fixed to the second diaphragm to open and close the communication passage in the fourth chamber.
A first spring that applies a predetermined biasing force to the first diaphragm is provided in the second chamber between the diaphragms, and the partition wall and the second
In the third chamber between the diaphragms, the second diaphragm is provided with a second spring that exerts a stronger biasing force than the biasing force of the first spring, the first chamber is provided with an atmospheric passage for guiding the atmosphere, and the second chamber is provided with an intake passage. A negative pressure passage that guides the negative pressure of the intake pipe is provided, and a tank passage that connects the third chamber to the upper portion of the fuel tank is provided, so that it is generated in the fuel tank when the internal combustion engine is stopped or fuel is supplied to the fuel tank. The evaporated fuel is collected in the canister to prevent the evaporated fuel from being released into the atmosphere, preventing air pollution.Also, when the internal pressure of the fuel tank increases during operation of the internal combustion engine, the communication passage is opened. It is possible to securely close the fuel tank so that fuel cannot be supplied to the fuel tank, and safety can be ensured.

[Brief description of drawings]

FIG. 1 is a system configuration diagram of an evaporated fuel control device.

FIG. 2 is a configuration diagram of a control valve.

FIG. 3 is a configuration diagram of a tank internal pressure control valve.

FIG. 4 is a configuration diagram of an air cut valve.

FIG. 5 is a configuration diagram of a pressure regulating valve.

FIG. 6 is a configuration diagram showing an operation of a control valve when the internal combustion engine is stopped.

FIG. 7 is a configuration diagram showing an operation of a control valve when refueling a fuel tank.

FIG. 8 is a configuration diagram showing an operation of a control valve during operation of the internal combustion engine.

FIG. 9 is a configuration diagram of a conventional evaporated fuel control device.

[Explanation of symbols]

 2 Internal combustion engine 6 Intake passage 8 Surge tank 16 Fuel tank 36 Evaporative fuel control device 38 Evaporation passage 40 Purge passage 42 Canister 46 Atmosphere communication passage 48 Air cut valve 58 Tank internal pressure control valve 72 Control means 84 Control section 88 Communication passage 92 Control valve

Claims (1)

[Claims] 1. An evaporation passage, which is generated in the fuel tank during the stop of the internal combustion engine, between the evaporation passage communicating with the inside of the fuel tank and the purge passage communicating with the intake passage of the intake system of the internal combustion engine, A canister is provided which adsorbs and holds the introduced vaporized fuel and releases the vaporized fuel that is adsorbed and held by the atmosphere introduced from the atmosphere communication passage and supplies it to the intake passage from the purge passage while the internal combustion engine is operating. In the evaporated fuel control device for an internal combustion engine, which is provided with a purge valve for controlling the amount of evaporated fuel to the intake passage according to the operating state of the internal combustion engine, a communication for connecting the fuel tank and the canister A passage is provided, a control valve is provided in the middle of this communication passage, and a partition that divides the valve housing of this control valve into two is provided. A first diaphragm that forms first and second chambers in the valve housing is provided between one side and the one side of the valve housing, and the valve housing is provided between the other side of the partition wall and the other side of the valve housing. A second diaphragm forming third and fourth chambers therein is provided, and a piston penetrated by the partition wall is provided so as to connect the first diaphragm and the second diaphragm, and the piston is provided with the second diaphragm. A valve body fixedly attached to the fourth chamber to open and close the communication passage in the fourth chamber is provided, and a first spring for applying a predetermined biasing force to the first diaphragm is provided in the second chamber between the partition wall and the first diaphragm. And a second spring for applying a stronger biasing force to the second diaphragm than the biasing force of the first spring in the third chamber between the partition wall and the second diaphragm. An air passage for guiding the atmosphere to the first chamber, a negative pressure passage for guiding the negative pressure of the intake pipe of the intake passage to the second chamber, and connecting the third chamber and the upper portion of the fuel tank. An evaporated fuel control device for an internal combustion engine, characterized in that a tank passage communicating with the evaporated fuel is provided.