JPH051643Y2 - - Google Patents

Description

[Detailed explanation of the idea] [Industrial application field]

This invention guides the evaporated fuel generated in the fuel tank when refueling a vehicle to the canister and adsorbs it.
The present invention relates to an evaporated fuel control device that guides the evaporated fuel adsorbed by the canister to an engine intake system and removes the evaporated fuel.

[Conventional technology]

Conventionally, this type of device was developed by, for example, Japanese Patent Application Laid-Open No.
As shown in Publication No. 49621, a pressure-responsive opening/closing valve is provided in the purge passage between the purge port at the upstream or downstream position of the throttle valve and the charcoal canister, and the purge passage is opened and closed in relation to the opening degree of the throttle valve. death,
It is known to be possible to terminate the emission of evaporated fuel during short-term operation of a vehicle. Furthermore, as shown in Japanese Utility Model Publication No. 53-75617, a control valve is provided in the vapor passage that leads the evaporated fuel from the fuel tank to the intake passage of the engine, and this vapor passage is closed only during idling operation. There is also.

[Problem that the idea aims to solve]

However, none of the above conventional examples actively prevents the vaporized fuel generated in the fuel tank from being released into the atmosphere during refueling. Currently, there are no particular regulations regarding the amount of evaporated fuel generated in a fuel tank that is released into the atmosphere during refueling at a gas station. However, new regulations are expected to come into effect starting around the 1990 model year for vehicles destined for the United States, so there is a need for a device that can effectively prevent the vaporized fuel generated in the fuel tank from being released into the atmosphere during refueling. The present invention was developed in response to the above-mentioned needs, and is capable of proactively preventing the release of evaporated fuel generated in the fuel tank into the atmosphere during refueling, as well as reducing the amount of evaporated fuel in the canister used. An object of the present invention is to provide an evaporated fuel control device that can efficiently restore adsorption capacity.

[Means to solve the problem]

In order to achieve the above object, the present invention introduces the vaporized fuel generated in the fuel tank during refueling to a canister and adsorbs it, and guides the vaporized fuel adsorbed by the canister to the engine intake system to remove the vaporized fuel. The control device is provided with a three-way switching control valve that is operated by negative pressure in the intake pipe of the engine, and the control valve has a port that is open when the control valve is not in operation and communicates with the fuel tank via an air vent circuit, and is opened when the control valve is in operation. The means is such that the port is communicated with the engine intake system via a withdrawal circuit, and the normally open port is communicated with the canister via an adsorption circuit.

[Effect]

According to the evaporative fuel control device that employs such a means, when the engine is stopped, the control valve is in an inactive state, and the air vent circuit and the adsorption circuit are connected through the port that is open when the engine is not in operation and the port that is normally open. communicate. Therefore, evaporated fuel generated in the fuel tank during refueling is guided to the canister and adsorbed. At that time, the port to the withdrawal circuit that communicates with the engine intake system is closed, so
The release of vaporized fuel into the atmosphere is actively prevented. During operation of the engine, the control valve is in an activated state, and the withdrawal circuit and the adsorption circuit communicate through a port that is open when the control valve is activated and a port that is normally open. Therefore, the evaporated fuel adsorbed by the canister is guided to the engine intake system and removed. At this time, since the port to the air vent circuit communicating with the fuel tank is closed, the canister stops adsorbing evaporated fuel and recovers its adsorption capacity.

【Example】

Hereinafter, one embodiment of the present invention will be described in detail with reference to FIGS. 1 to 3. First, in FIG. 1 showing a cross section of a control valve, reference numeral 1 indicates a valve body, 2 indicates a diaphragm case, and 3 indicates a diaphragm held between the valve body 1 and the diaphragm case 2. Further, reference numeral 4 indicates a diaphragm chamber, and 5 indicates a spring disposed within the diaphragm chamber 4, and this spring 5 urges the diaphragm 3 downward. Further, the reference numeral 6 indicates a rod fixed to the center of the lower surface of the diaphragm 3, the reference numeral 7 indicates a disc-shaped valve fixed to the lower end of the rod 6, and the reference numeral 8 indicates a seat plate. 6
is inserted through the through hole 8 and is opened and closed by the valve 7.
a is opened in the center, and a small-diameter leak hole 8b is opened in the peripheral portion away from the conduction hole 8a. Further, reference numeral 10 indicates an intake negative pressure introduction pipe, and reference numeral 11 indicates an air vent circuit from the fuel tank, and this air vent circuit 11 is connected to an upper chamber above the seat plate 8 in the valve body 1. moreover,
Reference numeral 12 indicates an adsorption circuit that communicates with the canister 18 and is connected to a lower chamber below the seat plate 8 in the valve body 1 . Reference numeral 13 indicates a breakaway circuit whose end is connected so as to protrude into the lower chamber of the valve body 1 and communicates with the intake system of the engine.The end thereof is bent upward and the tip 13a cooperates with the valve 7. This serves as a working seat section. Next, when refueling the vehicle (when adsorbing evaporative fuel)
In FIG. 2 showing the state of the vehicle and FIG. 3 showing the state when the vehicle is running (when the fuel vapor is removed), reference numeral 15 is a fuel tank, 16 is an inlet pipe having a leak prevention valve at the inlet, and 17 is a fuel tank. The fuel guns 18 each indicate a canister, and activated carbon for adsorbing evaporated fuel is housed inside the canister 18. Further, reference numeral 19 indicates an air filter, 20 a throttle valve, 21 an intake manifold, and 22 an engine. Next, the operation of the evaporative fuel control device of one embodiment having such a configuration will be explained. When refueling a vehicle, the fuel gun 17 is inserted into the inlet pipe 16 while being sealed by the leakage valve, as shown in FIG.
Fuel is injected into the fuel tank 15. At this time, since the engine 22 is stopped, no intake negative pressure is generated, and the inside of the intake pipe near the throttle valve 20 is at approximately atmospheric pressure. Therefore, the intake negative pressure introduction pipe 1
The inside of the diaphragm chamber 4 of the control valve, which communicates with the intake pipe through 0, is also at approximately atmospheric pressure. Close this and open the through hole 8a of the seat plate 8. Therefore, evaporated fuel generated in the fuel tank 15 as fuel is injected is introduced into the canister 18 via the air vent circuit 11, the communication hole 8a in the control valve, and the adsorption circuit 12, and is adsorbed by the activated carbon inside. . Therefore, the evaporated fuel gas generated in the fuel tank 15 is not released directly into the atmosphere from the inlet of the inlet pipe 16 or is released into the atmosphere from the air filter 19 via the separation circuit 13 to the engine 22. This makes it possible to significantly reduce the amount of evaporated fuel released into the atmosphere. On the other hand, when the engine 22 is started after refueling and the throttle valve 20 is opened to start running the vehicle, the inside of the diaphragm chamber 4 of the control valve is passed through the intake negative pressure introduction pipe 10 as shown in FIG. Intake negative pressure is introduced, the diaphragm 3 moves upward against the urging force of the spring 5, and the valve 7 opens the distal end 13a of the withdrawal circuit 13 and closes the communication hole 8a. Therefore, the evaporated fuel adsorbed by the activated carbon in the canister 18 is sucked from the adsorption circuit 12 into the intake pipe of the engine 22 via the lower chamber in the control valve and the withdrawal circuit 13 by its intake negative pressure, and is adsorbed. It separates from the activated carbon that is the material. In this case, the vapor pressure generated in the fuel tank 15 is regulated by the small diameter leak hole 8b provided in the seat plate 8, but the amount of leakage is extremely small, so the activated carbon in the canister 18 is
Its adsorption performance is efficiently restored and it stands by so that it can sufficiently adsorb the evaporated fuel that will be generated during the next refueling.

[Effect of the invention] As explained above, according to the invention, when the engine is stopped, the control valve is in an inactive state, and the air vent circuit and the adsorption circuit are connected through the port that is open when the engine is not in operation and the port that is normally open. communicate. Therefore, evaporated fuel generated in the fuel tank during refueling is guided to the canister and adsorbed. At this time, since the port to the withdrawal circuit communicating with the engine intake system is closed, it is possible to actively prevent the vaporized fuel from being released into the atmosphere. During operation of the engine, the control valve is in an activated state, and the withdrawal circuit and the adsorption circuit communicate through a port that is open when the control valve is activated and a port that is normally open. Therefore, the evaporated fuel adsorbed by the canister is guided to the engine intake system and removed. At this time, since the port to the air vent circuit communicating with the fuel tank is closed, the canister stops adsorbing evaporated fuel, so that the canister's ability to adsorb evaporated fuel can be restored.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing the configuration of a control valve in an embodiment of the present invention, FIG. 2 is a diagram showing a state during refueling in one embodiment, and FIG. 3 is a diagram showing a state in one embodiment during driving. FIG. 1...Valve body, 3...Diaphragm, 7
...Valve, 10...Intake negative pressure introduction pipe, 11...
Air vent circuit, 12...adsorption circuit, 13...separation circuit, 15...fuel tank, 18...canister, 22...engine.

Claims (1)

[Scope of Claim for Utility Model Registration] An evaporated fuel control device that guides evaporated fuel generated in a fuel tank during refueling to a canister and adsorbs it, and guides the evaporated fuel adsorbed by the canister to the engine intake system for release, A three-way switching control valve is provided which is operated by negative pressure in the intake pipe of the engine, and the control valve has a port that opens when it is not in operation and communicates with the fuel tank via an air vent circuit.
A vaporized fuel control device characterized in that a port that opens when activated is connected to an engine intake system via a withdrawal circuit, and a normally open port is connected to a canister via an adsorption circuit.