JP2003184665A - Evaporative fuel discharge control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent vapor generated in a fuel tank at engine idling from being emitted into the air through a canister. <P>SOLUTION: A canister 34 is communicated with a surge tank 54 by a purge line 50 connected to a vapor line 36, and D-VSV 56 and a buffer canister 58 are disposed on the purge line 50. A control valve 66 is placed between a connection part 67 with the purge line 50 in the vapor line 36 and the fuel tank 10. This control valve 66 is connected to a control circuit 22 and closed at idling. <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 an evaporative emission control device, and more particularly to an evaporative emission control device mounted on a vehicle such as an automobile.

[0002]

2. Description of the Related Art Conventionally, in a fuel vapor emission control device installed in a vehicle such as an automobile, vaporized fuel (vapor) is collected in the middle of a line (communicating passage) connecting an intake line of an engine and a fuel tank. Some have an evaporated fuel collecting device (canister) that performs (adsorption and holding), one example of which is Japanese Patent Laid-Open No.
No. 001-206080.

As shown in FIG. 2, in this fuel vapor discharge suppressing device, a fuel tank 100 and a canister 102 are provided.
A valve unit 110 in which a relief valve 106 and a control valve 108 are integrated is arranged on a vapor line 104 connecting with. Further, the relief valve 106 is provided in a passage 112 that bypasses the control valve 108, and the negative pressure chamber 114 side of the relief valve 106 is the canister side 108A of the control valve 108.
Is in communication with. In the control valve 108 configured by the solenoid valve, when the internal pressure of the fuel tank side 108B is lower than the internal pressure of the canister side 108A by a predetermined value or more during parking, the valve element 108C is the spring 108D.
It is designed to move in the direction of the fuel tank side 108B and open the valve in opposition to the urging force to prevent the internal pressure of the fuel tank 100 from dropping significantly during parking.

[0004]

However, in this evaporative emission control device, the valve body 108 of the control valve 108 is in idle, that is, when the vehicle is stopped and the engine is operating.
C moves in the valve opening direction. As a result, vapor may be released to the atmosphere via the canister 102 during idling.

In view of the above facts, it is an object of the present invention to provide an evaporated fuel emission suppressing device capable of suppressing vapor generated in a fuel tank at the time of idling from being released to the atmosphere through a canister.

[0006]

According to a first aspect of the present invention, there is provided a vapor line for suppressing vaporized fuel discharge, a vapor line communicating a fuel tank and a canister, and a vapor line provided in the vapor line.
And a control valve which is closed at the time of idling.

Therefore, at the time of idling, the control valve provided in the vapor line connecting the fuel tank and the canister is closed, so that the vapor generated in the fuel tank at the time of idling can be prevented from flowing into the canister through the vapor line. As a result, it is possible to prevent the vapor adsorbed by the canister by being pushed by the vapor passing through the vapor line from being released into the atmosphere through the opening of the canister.

According to a second aspect of the present invention, in the evaporative emission control device according to the first aspect, the control valve opens when the internal pressure of the fuel tank is equal to or higher than a predetermined pressure when the vehicle is traveling. To do.

Therefore, in addition to the contents of the first aspect, the control valve opens when the internal pressure of the fuel tank is equal to or higher than a predetermined pressure when the vehicle is running, so that the internal pressure of the fuel tank becomes equal to or higher than the predetermined value when the vehicle is running. Can be surely purged.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of an evaporated fuel emission suppressing device according to the present invention will be described with reference to FIG.

As shown in FIG. 1, in the evaporative emission control device of the present embodiment, one end of an inlet pipe (fuel filling pipe) 12 penetrates the side wall of the fuel tank 10 and the inside of the fuel tank 10 is penetrated. It is inserted, and the other end reaches the fuel filler port 14 provided in the vehicle side wall.

A refueling cap 16 is attached to the refueling port 14. When refueling, the fuel lid 18 is opened and the refueling cap 16 is removed, so that a refueling gun (not shown) can be inserted. . When refueling, the fuel level in the inlet pipe 12 rises, and when a sensor provided in the refueling gun detects a full state, refueling from the refueling gun automatically stops. Further, the fuel lid 18 is provided with an opening / closing detection switch 20 for detecting opening / closing of the fuel lid 18, and the opening / closing detection switch 20 is connected to a control circuit 22. A ventilation pipe 24 is provided in the inlet pipe 12, and a well-known fuel lid opener switch 23 is also connected to the control circuit 22.

A heat insulating material 30 is disposed on the inner surface of the outer tank shell 28 of the fuel tank 10. Also, the fuel tank 1
A float valve (cut-off valve) 31 for full tank detection and a float valve 32 for rollover are provided in 0, and the canister 3 is provided for the float valves 31 and 32.
A vapor line 36 (also called an evaporation line) reaching 4 is connected.

The canister 34 has a vapor line 36.
Is connected to a surge tank 54 which is in communication with the air cleaner 52 by a purge line 50 connected to the engine 40. A D-VSV (vacuum switching valve) 56 and a buffer canister 58 are connected to the engine 40 at an intermediate portion of the purge line 50. The D-VSV 56 and the buffer canister 58 are arranged in series in this order from the side.

Purge line 5 in vapor line 36
An electromagnetic control valve 66 is disposed between the fuel tank 10 and the connecting portion 67 connected to 0, and the control valve 66 includes:
It is connected to the control circuit 22. An atmosphere line 68 is connected to the canister 34.
At 8, an atmosphere valve 69 connected to the control circuit 22 is provided. Therefore, for example, it is possible to draw the atmosphere into the canister 34 by utilizing the negative pressure generated by opening and closing the throttle valve.

At the top of the fuel tank 10, a pressure sensor 5
8 is attached, and the pressure sensor 58 is connected to the control circuit 22. A sub tank 60 is arranged inside the fuel tank 10. A fuel pump 62 is provided inside the sub tank 60.
The fuel pump 62 includes an injector 63 of the engine 40.
Is connected to the fuel supply pipe 64.

The control circuit 22 opens the control valve 66 when refueling, that is, when the open / close detection switch 20 detects the open state of the fuel lid 18 (refueling state). Further, the control circuit 22 determines that the pressure detected by the pressure sensor 58 while the vehicle is traveling becomes higher than a predetermined pressure (relief pressure during traveling, minimum valve opening pressure) set in advance (high pressure state), and The control valve 66 is opened when the fuel temperature in the fuel tank 10 detected by the temperature sensor (not shown) becomes higher than a preset predetermined temperature (high temperature state).

Further, the control circuit 22 closes the fuel tank 10 by closing the control valve 66 even when the engine 40 is idling when the vehicle is stopped, and opens the control valve 66 when the vehicle starts traveling again. Has become.

Further, when the internal pressure of the fuel tank 10 is in a certain negative pressure state, the control circuit 22 keeps the control valve 66 closed even when the vehicle is traveling.

The control circuit 22 is based on the vehicle speed.
It is designed to determine whether the vehicle is stopped or has started running.

Next, the operation of this embodiment will be described.

In the present embodiment, for example, when the vehicle is stopped by a signal or the like and is in an idle state, that is, when the engine is operating while the vehicle is stopped, the vapor line 36 that connects the fuel tank 10 and the canister 34 is communicated. When the control valve 66 provided in the above is opened, the control valve 66 is closed, and when the control valve 66 is closed, the closed state is maintained. Therefore, it is possible to prevent the vapor generated in the fuel tank 10 from flowing into the canister 34 when the engine 40 is idle. As a result, it is possible to prevent the vapor adsorbed to the canister 34 by being pushed by the vapor passing through the vapor line 36 from being released from the canister 34 to the atmosphere.

Further, in this embodiment, when the vehicle starts traveling again and the internal pressure of the fuel tank 10 is equal to or higher than the predetermined pressure, the control valve 66 is opened and the internal pressure of the fuel tank 10 does not reach the predetermined pressure. In some cases, the control valve 66 is kept closed. Therefore, when the internal pressure of the fuel tank 10 becomes equal to or higher than a predetermined value while the vehicle is traveling, it is possible to surely perform the purge.

Therefore, by disposing the evaporated fuel emission suppressing device of the present embodiment in a vehicle in which the engine purge is stopped even during idling, or in a vehicle in which the purging amount is smaller than in normal running even during idling, the fuel tank is idled during idling. The vapor generated inside can be suppressed from being released to the atmosphere through the canister.

Further, by disposing the evaporated fuel discharge suppressing device of this embodiment in a vehicle in which the canister 34 is exclusively used for refueling, it is possible to prevent vapor from flowing from the fuel tank 10 to the canister 34 except when refueling.

The control by the control circuit 22 may be replaced as follows.

The control circuit 22 may control the opening / closing control of the control valve 66 based on the operation signal of the D-VSV 56.
For example, when the D-VSV 56 is open, the control valve 66 is opened, and when the D-VSV 56 is closed, the control valve 66 is closed, so that the fuel tank 1 can be operated when the engine 40 is idle.
The vapor generated in 0 may flow to the canister 34, and by being pushed by the vapor, the vapor adsorbed to the canister 34 may be suppressed from being released to the atmosphere through the opening of the canister 34.

In the above, the present invention has been described in detail with respect to specific embodiments, but the present invention is not limited to such embodiments, and various other embodiments within the scope of the present invention. It is obvious to a person skilled in the art that

[0029]

According to the vaporized fuel emission control device of the present invention as set forth in claim 1, the vapor line for communicating the fuel tank and the canister and the control valve provided in the vapor line and closed at the time of idling are used. It has an excellent effect that vapor generated in the tank can be suppressed from being released to the atmosphere through the canister.

According to a second aspect of the present invention, in the evaporative emission control device according to the first aspect, the control valve is opened when the internal pressure of the fuel tank is equal to or higher than a predetermined pressure while the vehicle is traveling. In addition to the above effect, there is an excellent effect that purging can be performed when the internal pressure of the fuel tank becomes equal to or higher than a predetermined value while the vehicle is traveling.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing an evaporated fuel emission suppressing device according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a conventional evaporated fuel emission suppressing device.

[Explanation of symbols]

10 Fuel tank 22 Control circuit 34 canister 36 Vapor Line 40 engine 50 Purge line 56 D-VSV 68 Atmospheric line 69 atmosphere valve

Claims (2)

[Claims] 1. An evaporative emission control device, comprising: a vapor line that connects a fuel tank and a canister; and a control valve that is provided on the vapor line and that closes at idle. 2. The evaporative emission control device according to claim 1, wherein the control valve opens when the internal pressure of the fuel tank is equal to or higher than a predetermined pressure when the vehicle is traveling.