JP2599824Y2 - Vapori Cover System - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vapour cover system for an internal combustion engine, and in particular, there is no fear that fuel vapor is released from the cap to the atmosphere when the cap of the fuel tank is opened for fuel injection. The present invention relates to a vapor cover system that can be effectively prevented.

[0002]

2. Description of the Related Art In a conventional internal combustion engine, as a countermeasure against the problem that the fuel vapor is released into the atmosphere, a canister communicating with a fuel tank and adsorbing and holding the fuel vapor is provided so that the operating state of the internal combustion engine is controlled to a predetermined value. Some systems include a vapor cover system that controls the fuel vapor adsorbed and held in the canister to be discharged to the intake system of the internal combustion engine when the purge fuel is in a purge region satisfying the conditions.

FIG. 6 shows such a vapor cover system for an internal combustion engine.

[0006] In FIG. 6, reference numeral 102 denotes an air cleaner, and an intake pipe 104 communicated with the air cleaner 102.
Is connected to an internal combustion engine 108 via a carburetor (not shown) and a throttle body 106. A throttle valve 110 is provided on the throttle body 106.

In FIG. 6, reference numeral 112 denotes a fuel tank provided with a fuel injection pipe 114. Fuel tank 112
Communicates with the upper part of the canister 118 through a pipe 116. The canister 118 has an opening 12 opened to the atmosphere at a lower portion opposite to a mounting portion of the pipe 116.
0 is provided.
Through the intake pipe 4 to the downstream side of the throttle valve 110.

In the above-described configuration, since the on-off valve 124 is normally closed, the fuel vapor generated in the fuel tank 112 flows from the pipe 116 to the canister 118 as shown by the arrow u, and is adsorbed by the canister 118. , Stored.

When the operating state of the internal combustion engine 108 is in a purge state that satisfies a predetermined condition, the opening valve 124 is opened. In this state, the throttle body 1
Since the throttle valve 110 provided at 06 is opened at a predetermined angle and a flow of intake air is generated in the intake pipe 104,
Since the air 22 is sucked in the flow shown by the arrow w, the evaporated fuel adsorbed inside the canister 118 is sucked out, and the fresh air is instead supplied from the opening 120 to the canister 118 as shown by the arrow v. As it flows, the interior of the canister 118 is replaced with fresh air.

Further, as such a vapor cover cover system for an internal combustion engine, there are those disclosed in Japanese Utility Model Laid-Open No. 63-121557 and Japanese Utility Model Laid-Open No. 63-126550.

Japanese Patent Laid-Open Publication No. 63-121775 discloses a fuel tank which is connected to a fuel tank and an evaporative fuel adsorbing portion when an ignition switch is turned off and a refueling switch is turned on. The valve located in the middle of the pipe to release the pressure is opened.

Japanese Unexamined Utility Model Publication No. 63-126550 discloses a main canister for recovering fuel vapor generated in a fuel tank and an auxiliary canister communicating with the fuel tank only at the time of fuel injection. The control valve provided in the purge passage communicating from the main canister to the intake pipe is opened under the operating condition where the amount is equal to or more than the first set value, and the auxiliary canister is operated under the operating condition where the intake air amount is equal to or more than the second set value which is larger than the first set value. The control valve provided in the purge passage communicating with the intake pipe is opened.

[0011]

By the way, in the conventional vapor cover system, when fuel is injected into the fuel tank, the air containing the evaporated fuel in the fuel tank corresponding to the volume of the injected fuel is fueled. Is released into the atmosphere from the inlet. The release of the fuel vapor into the atmosphere in this way is important from the viewpoint of preventing air pollution, but it has conventionally been considered that the problem does not stop. However, there is a movement to be legally regulated in the United States and other countries, and it is necessary to take immediate measures.

[0012] In order to solve the above-mentioned problem, the present invention provides a vapor cover system capable of storing air containing fuel vapor in a tank at the time of fuel injection so that the air can be properly treated after being stored without being released to the atmosphere. The challenge is to achieve it.

[0013]

SUMMARY OF THE INVENTION Therefore, in order to eliminate the above-mentioned disadvantages, the present invention provides an evaporative fuel which is absorbed and held in a canister when an operation state of the internal combustion engine satisfies a predetermined condition, to an intake system of the internal combustion engine. In a vaporizer cover system for an internal combustion engine controlled to discharge, a canister communicating from a fuel tank via a first pipe via a check valve and a vapor tank communicating from a fuel tank via a second pipe via a first on-off valve are respectively provided. A third pipe for directly communicating between the canister and the vapor tank; and a fourth pipe for communicating the vapor tank via a second on-off valve to a throttle valve downstream side of an intake pipe of the internal combustion engine. It is connected to the downstream side of the throttle valve of the intake pipe of the internal combustion engine via the three on-off valves, and the flow ratio of the purge to the third pipe is preset. A fifth pipe is provided to open the first on-off valve during fuel injection into the fuel tank and during operation of the internal combustion engine, and to open the first to third on-off valves during operation of the internal combustion engine and purge operation. It is characterized in that a control unit for performing control as much as possible is provided.

[0014]

According to the structure of the present invention, during the fuel injection operation and the operation of the internal combustion engine, the first on-off valve is opened and the second on-off valve and the third on-off valve are closed, so that the fuel vapor is removed. The amount of air corresponding to the supplied fuel flows and is stored in the vapor tank.
When the internal pressure in the fuel tank is increased by closing the third on-off valve, that is, when the amount of evaporated fuel becomes a predetermined amount or more, the evaporated fuel flows into the canister and is stored. By opening the first to third opening / closing valves, the evaporated fuel adsorbed in the canister and the vapor tank is discharged to the downstream side of the throttle valve in the suction pipe of the internal combustion engine, and the evaporated fuel is not accumulated in the fuel tank. Even when fuel is injected into the fuel tank, the evaporated fuel is not released to the atmosphere, and there is no possibility that the pressure inside the fuel tank becomes negative.

[0015]

Next, an embodiment of the present invention will be described in detail with reference to the drawings.

FIGS. 1 to 5 show the structure of a vapor cover system according to an embodiment of the present invention.

1 to 5, reference numeral 2 denotes an air cleaner, and an intake pipe 4 connected to the air cleaner 2 is connected to an internal combustion engine 8 via a throttle body 6.
The throttle body 6 is provided with a throttle valve 10, and the intake pipe 4 is constituted by an upstream side 4-a and a downstream side intake manifold 4-b of the throttle body 6.

In FIG. 1, reference numeral 12 denotes an injector. The throttle body 6 is provided with a throttle sensor 14 for detecting the operation angle of the throttle valve 10.

A fuel injection pipe 18 is provided in the fuel tank 16, and a fuel cap 20 is mounted on the fuel injection pipe 18.

A first pipe 22 from the fuel tank 16 is connected to a canister 2 using activated carbon via a check valve 24.
The canister 26 is provided with an opening 28 open to the atmosphere. In this embodiment, the canister 2
Reference numeral 6 denotes the case of a bottom type in which the opening 28 is provided at the upper part.

The second pipe 30 from the fuel tank 16
Communicates with the vapor tank 34 via the first on-off valve 32. A third pipe 36 communicates the canister 26 with the vapor tank 34.

A fourth pipe 38 from the vapor tank 34 communicates via a second on-off valve 40 with an intake manifold 4-b on the downstream side of the throttle body 6 of the intake pipe 4.

The fuel injection pipe 18 of the fuel tank 16
A fuel injection chamber 42 is provided at the distal end portion, and the fuel injection chamber 42 is provided.
A fuel cap 20 is put on the tip of the fuel injection pipe 18 and a body side cover 44 is provided.

Further, a body side cover 44 is provided in the fuel injection chamber 42.
A switch 46 is provided which is turned on when is opened,
When the switch 46 is turned on, an electric circuit is provided so that the first opening / closing valve 32 is opened by the power supply 48.

A control unit 50 controls the internal combustion engine 8 by inputting the aforementioned throttle sensor 14 and other predetermined signals and outputting them to the injector 12 and the like. The control unit 50 operates the second on-off valve 40 when the internal combustion engine 8 enters a predetermined operation state described later, and operates the first on-off valve 32 so as to operate in parallel with the switch 46. A circuit is provided.

Inside the vapor tank 34, a plurality of partition walls 52 each having an open end are provided in parallel so as to alternately mount and open the upper and lower portions, and the second pipe 30, the fourth pipe 38, and the third pipe 36 is separated. Therefore, when a liquid component is contained in the evaporated fuel entered into the vapor tank 34 or a part of the evaporated fuel returns to the liquid, the gas component and the liquid component are naturally separated.

Reference numeral 54 denotes a fuel injection gun, and reference numeral 56 denotes a seal member for closing a gap between the fuel injection pipe 18 and the fuel injection gun 54 to prevent the fuel vapor in the fuel tank 16 from leaking.

At this time, the canister 26 is connected to the downstream side of the throttle valve 10 of the intake pipe 4 of the internal combustion engine 8 via the third opening / closing valve 36, and the ratio of the purge to the third pipe 36 is preset. A fifth pipe 72 is provided to open the first on-off valve 32 at the time of fuel injection into the fuel tank 16 and at the time of operation of the internal combustion engine.
The first to third opening / closing valves 3 when
The control section 50 for controlling the opening of the 2, 40, 74 is provided.

More specifically, the canister 26 and the intake manifold 4-b on the downstream side of the throttle body 6 provided in the intake pipe 4 are connected to the third on-off valve 7 by a fifth pipe 72.
4, and communicate with each other.

That is, from the canister 26, the fifth pipe 72 is connected to the intake manifold 4 on the downstream side of the throttle body 6 of the intake pipe 4 via the third on-off valve 74.
-B.

Next, the operation of the above configuration will be described.

FIG. 2 shows a state in which the operation of the internal combustion engine 8 is stopped and the fuel cap 20 and the body side cover 44 of the fuel tank 16 are closed.

In FIG. 2, the switch 46 detects that the body side cover 44 is closed, and the first opening / closing valve 32, the second opening / closing valve 40, and the third opening / closing valve 74 are operated by the control unit 50.
When the fuel vapor pressure in the fuel tank 16 becomes equal to or higher than the set pressure of the check valve 24, the evaporated fuel flows into the canister 26 via the check valve 24 (see arrow a) and is adsorbed. Further, a part of the evaporated fuel flowing into the canister 26 flows through the third pipe 36 into the vapor tank 34 (see arrow b) and is stored.

FIG. 3 shows a situation in which the internal combustion engine 8 is operating, but the control unit 50 determines that the purge is not in operation. That is, in a state where the internal combustion engine 8 is operating but the purge is not operating, the first opening / closing valve 32 is opened, but the second opening / closing valve 40 and the third opening / closing valve 74 are closed. Therefore, the fuel vapor in the fuel tank 16 is supplied to the second pipe 3
From 0, the gas flows into the vapor tank 34 (see arrow c), and further flows into the canister 26 via the third pipe 36 (see arrow d), and is adsorbed. When the fuel vapor pressure in the fuel tank 16 becomes equal to or higher than the set pressure of the check valve 24,
The gas flows into the canister 34 via the check valve 24 (see arrow a) and is absorbed.

FIG. 4 shows a situation when the internal combustion engine 8 is operated and enters a preset purge operation state. When the control unit 50 determines the purge operation and enters the purge operation state, the first open / close valve 30, the second open / close valve 40, and the third open / close valve 74 are opened, respectively.

In this situation, the throttle valve 10 of the throttle body 6 provided in the intake pipe 4 is opened at a predetermined angle, and a flow of intake air is generated in the intake pipe 4. Therefore, the air in the fourth pipe 38 and the fifth pipe 72 is sucked into the intake manifold 4-b on the downstream side of the throttle body 6 provided in the intake pipe 4, so that the fuel vapor accumulated in the vapor tank 34 is discharged to the fourth pipe 38. The gas is discharged from the pipe 38 to an intake manifold 4-b downstream of the throttle body 6 provided in the intake pipe 4 (see arrow e).

Further, the fuel vapor accumulated in the canister 24 also flows from the third pipe 36 via the vapor tank 34 (see arrow f), and flows from the fourth pipe 38 downstream of the throttle body 6 provided in the intake pipe 4. Into the intake manifold 4-b on the side (see arrow e). At this time, a flow of fresh air (see arrow g) flows from the opening 28 of the canister 26 opened to the atmosphere, and the evaporated fuel adsorbed in the canister 26 is replaced with fresh air.

Further, the fresh air flowing through the canister 26 flows from the third pipe 36 to the vapor tank 34 (see arrow f), and replaces the fuel vapor in the vapor tank 34 with fresh air.

Further, the evaporated fuel in the fuel tank 16 flows to the vapor tank 34 via the second pipe 30 (see arrow c), and flows from the fourth pipe 38 to the downstream side of the throttle body 6 provided in the intake pipe 4. It is released to the intake manifold 4-b (see arrow e). When the fuel vapor pressure in the fuel tank 16 exceeds the set pressure of the check valve 24, the fuel vapor pressure in the fuel tank 16 flows to the canister 26 via the check valve 24 (see arrow a).

The fuel vapor accumulated in the canister 26 in parallel with the above flow is directly discharged from the fifth pipe 72 to the intake manifold 4-b downstream of the throttle body 6 provided in the intake pipe 4. (See arrow p).

As described above, the fuel vapor accumulated in the canister 26 is supplied to the third pipe 36 passing through the vapor tank 34.
And the fifth pipe 72 is discharged separately.
In these two paths, the flow dividing ratio of the purge can be set by setting the respective flow resistances in advance.

That is, from the fuel tank 16 to the second pipe 3
If the amount to be purged after passing through zero is too large, the pressure inside the fuel tank 16 may become negative. Therefore, it is possible to prevent this by providing a path directly discharging from the canister 26 through the fifth pipe 72. it can.

FIG. 5 shows a state in which the operation of the internal combustion engine 8 is stopped and a fuel injection operation into the fuel tank 16 is performed. For fuel injection, the body side lid 44 is opened, the fuel cap 20 is removed, and a fuel injection gun 54 is inserted into the fuel injection pipe 18 instead. In FIG. 5, reference numeral 56 denotes a seal member which closes a gap between the fuel injection pipe 18 and the fuel injection gun 54 to prevent the fuel vapor in the fuel tank 16 from leaking.

When the body side cover 44 is opened, the switch 4
6 operates to open the first on-off valve 32. When fuel is injected from the fuel injection gun 54, the air in the fuel tank 16 flows through the second pipe 30 (see the arrow j), and the vapor tank 34
And flows sequentially between the partition walls 52 in the vapor tank 34 (see arrow k), flows from the third pipe 36 to the canister 26 (see arrow m), and further flows out from the opening 28 of the canister 26 to the atmosphere. (See arrow n). During this flow, the evaporated fuel contained in the air is discharged to the canister 2.
The liquid component of the fuel contained in the air during this flow is separated and remains in the vapor tank 34. Therefore, the air flowing out from the opening 28 to the atmosphere does not include the evaporated fuel.

As described above, the fuel vapor in the fuel tank 16 is supplied from the vapor tank 34 to the canister 2 at the time of fuel injection.
6 and is thus absorbed by the vapor tank 34 or the canister 26 before being released to the atmosphere.
Therefore, unlike the conventional case, the fuel vapor in the fuel tank 16 is not directly discharged to the atmosphere.

Thus, at the time of fuel injection and operation of the internal combustion engine 8, the control unit 50 opens the first opening / closing valve 32, closes the second opening / closing valve 40 and the third opening / closing valve 74, and stores the evaporated fuel in the vapor tank. 34, and then flow to the canister 26, where the fuel vapor is accumulated respectively. When the fuel is charged into the fuel tank 16, the fuel vapor in the fuel tank 16 is collected in the canister 26 and the vapor tank 34 without being released to the atmosphere. There is no danger that the fuel vapor in the fuel tank 16 will be released to the atmosphere, so that air pollution can be prevented, and there is no danger of violating any legal regulations that may be considered in the future, which is practically advantageous.

Further, when the internal combustion engine 8 is operated and the purge operation is performed, the first to third on-off valves 32, 4
By controlling the fuel tanks 0 and 74 to be opened, the fuel vapor accumulated in the canister 26 is discharged into two paths, the third pipe 36 and the fifth pipe 72, which pass through the vapor tank 34, and is discharged. From the tank 16 to the second pipe 30
If the amount to be purged through the fuel tank is too large, the fuel tank 1
Since there is a possibility that the inside of the tube 6 becomes negative pressure, this can be prevented by providing a path for directly discharging from the canister 26 by the fifth pipe 72.

Further, when the internal combustion engine 8 is stopped, the first to third on-off valves 32, 40 and 74 are closed to increase the internal pressure in the fuel tank 16, that is, when the amount of evaporated fuel becomes a predetermined amount or more, the evaporation is stopped. The fuel will flow to the canister and be stored, so there is no problem.

Further, since the vapor tank 34 having a predetermined volume is provided as described above,
4 has the effect of adjusting the pressure in the fuel tank 16 and the ability to remove the evaporated fuel in the fuel tank 16 in a short time.

Further, since the vapor tank 34 is provided with the plurality of partition walls 52, the air in the fuel tank 16 containing the evaporated fuel to be absorbed can be accumulated without directly discharging, and the fuel vapor in the partition wall 52 can be further stored. Since it has a function of separating liquids while the contained air flows, it is more suitable for adsorbing liquids than canisters.

[0051]

According to the present invention described above, a canister communicating from a fuel tank via a first pipe via a check valve and a vapor tank communicating from a fuel tank via a second pipe via a first on-off valve are provided, respectively. A third pipe for directly communicating the canister and the vapor tank is provided, and a fourth pipe for communicating the vapor tank via the second on-off valve to the throttle valve downstream side of the intake pipe of the internal combustion engine is provided, and the canister is connected to the third on-off valve. A fifth pipe, which communicates with a downstream side of a throttle valve of an intake pipe of the internal combustion engine through the third pipe and has a preset flow ratio of purge to the third pipe, is provided. When the on-off valve is opened and the internal combustion engine is operated and the purge operation is performed,
Since the control unit that controls to open the third on-off valve is provided,
When the fuel is injected and the internal combustion engine is operated, the first
The on-off valve is opened, the second on-off valve and the third on-off valve are opened, and the evaporated fuel flows into the vapor tank, then flows into the canister, where the evaporated fuel is accumulated, and the fuel tank is placed on a place where the fuel is charged into the fuel tank. The evaporative fuel in the fuel tank can be collected in the canister and the vapor tank without releasing it to the atmosphere, and there is no fear that the evaporative fuel in the fuel tank will be released to the atmosphere. There is no danger of conflicting with national regulations. When the internal combustion engine is operating and the purging operation is performed, the control unit controls the first to third opening / closing valves to be opened, so that the fuel vapor accumulated in the canister is supplied to the third pipe via the vapor tank and to the third pipe. If the amount discharged from the fuel tank through the second pipe is too large to be purged through the second pipe, a negative pressure may be generated in the fuel tank. This can be prevented by providing a path for direct discharge from the canister.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a vapor cover system showing an embodiment of the present invention.

FIG. 2 is a configuration and operation diagram illustrating an operation when the fuel tank is not opened when the operation of the internal combustion engine of the vapor recovery cover system is stopped.

FIG. 3 is a configuration and operation diagram illustrating an operation in a purge inoperative state during operation of the internal combustion engine of the vapor recovery cover system.

FIG. 4 is a configuration operation diagram illustrating an operation in a purge operation state during operation of the internal combustion engine of the vapor recovery cover system.

FIG. 5 is a configuration and operation diagram for explaining the operation of the vapor lip cover system during fuel supply.

FIG. 6 is a block diagram of a vapor cover system showing the prior art of the present invention.

[Explanation of symbols]

 Reference Signs List 2 air cleaner 4 intake pipe 8 internal combustion engine 16 fuel tank 24 check valve 26 canister 32 first on-off valve 34 vapor tank 40 second on-off valve 74 third on-off valve

Claims (1)

(57) [Scope of request for utility model registration] In a vapor cover cover system for an internal combustion engine, which controls to discharge evaporative fuel absorbed and held in a canister to an intake system of the internal combustion engine when an operation state of the internal combustion engine satisfies a predetermined condition, a check is performed from a fuel tank. base which communicates with the second pipe through the first opening and closing valve from the canister and the fuel tank connected by a first pipe via a valve
And Patanku respectively provided, first communicates with the throttle valve downstream side of the air intake pipe of the internal combustion engine Bepatanku <br/> via the second on-off valve provided with a third pipe that communicates the canister and Bepatanku directly Four pipes are provided, and the canister is
Downstream of the throttle valve in the intake pipe of the internal combustion engine via three on-off valves
To the third pipe,
A set fifth pipe is provided to open the first on-off valve at the time of fuel injection operation to the fuel tank and at the time of operation of the internal combustion engine, and at the same time at the time of operation of the internal combustion engine and at the time of purging operation .
A vapor cover system comprising a control unit for controlling to open the first to third on-off valves .