JP2002206464A - Evaporative fuel control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrict reevaporation of the liquefied fuel in a fuel tank. SOLUTION: The liquefied fuel liquefied in a cooling part 48A of a cooler 48 is made to enter a fuel storage part 48C through an opening part 48B. Except for the time of refueling, a solenoid valve 49 arranged in an outlet 48D of the fuel storage part 48C is opened by a signal from a control circuit 22, and the liquefied fuel passes through the solenoid valve 49, and enters a liquefied fuel return pipe 52 from the fuel storage part 48C, and flows inside the liquefied fuel return pipe 52, so as to return to the inside of the fuel tank 10 from a part near a suction filter 54A a fuel pump 54.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel vapor control system, and more particularly to a fuel vapor control system mounted on a fuel tank mounted on a vehicle such as an automobile.

[0002]

2. Description of the Related Art Conventionally, an evaporative fuel control device mounted on a fuel tank mounted on a vehicle such as an automobile has a gaseous mixture of evaporative fuel (evaporation) evaporated in the fuel tank and air (hereinafter referred to as vapor). And a canister for temporarily adsorbing the evaporated fuel in the vapor, one example of which is disclosed in Japanese Patent Application Laid-Open No. 6-147029.

As shown in FIG. 5, in such an evaporative fuel control device, a fuel tank 100 and a canister 102 are connected to each other, and a fuel gas outlet pipe 104 for sending the evaporative fuel evaporated in the fuel tank 100 to the canister 102 is provided. The fuel gas outflow pipe 1 is provided in the middle of the fuel gas outflow pipe 104.
A cooler 106 for cooling the evaporated fuel flowing through the fuel tank 04 and a fuel return pipe 110 for returning excess fuel not injected by the injector 108 to the fuel tank 100 are provided. In addition, a return pipe 112 for sending the liquefied fuel liquefied by the cooler 106 to the fuel return pipe 110 is provided, and a cross section of the fuel return pipe 110 at a connection part to which the return pipe 112 is connected is changed to a fuel return other than the connection part. By forming the venturi section smaller than the cross section of the pipe 110, the liquefied fuel can be reliably returned to the fuel tank while the size of the apparatus is reduced.

[0004]

However, since the liquefied fuel liquefied by the cooler 106 has many low-boiling components and is apt to be re-vaporized, in such an evaporative fuel control system, the fuel passing through the fuel return pipe 110 The liquefied fuel that has returned to the tank 100 receives heat in the fuel tank 100 and immediately revaporizes. As a result, the liquefaction efficiency is not good.

In view of the above, an object of the present invention is to provide an evaporative fuel control device capable of suppressing re-evaporation of liquefied fuel in a fuel tank.

[0006]

According to a first aspect of the present invention, there is provided an evaporative fuel control apparatus for cooling evaporative fuel generated in a fuel tank by a cooler disposed upstream of a canister. A liquefied fuel return pipe for returning the liquefied fuel to the vicinity of a fuel pump incorporated in the fuel tank.

Therefore, the liquefied fuel liquefied by the cooler passes through the liquefied fuel return pipe and is returned to the vicinity of the fuel pump built in the fuel tank. As a result, the liquefied fuel is sucked by the fuel pump before being vaporized again, so that re-vaporization of the liquefied fuel in the fuel tank can be suppressed.

According to a second aspect of the present invention, in the evaporative fuel control device according to the first aspect, a fuel storage unit for holding liquefied fuel liquefied by the cooler and an outlet of the fuel storage unit are provided. And a control valve that closes to hold the liquefied fuel in the fuel storage unit.

Therefore, in addition to the contents described in claim 1,
When fuel is supplied to the fuel tank, the fuel pump stops, so that the liquefied fuel cannot be sucked by the fuel pump.For example, in this case, the outlet of the fuel storage unit provided in the cooler is provided. The liquefied fuel can be held in the fuel storage unit by closing the control valve disposed in the fuel storage unit. As a result, re-vaporization of the liquefied fuel in the fuel tank can be suppressed even during refueling.

According to a third aspect of the present invention, there is provided the evaporative fuel control device according to the first aspect, wherein the liquefied fuel return pipe has a cooling means on an outer peripheral portion.

Therefore, in addition to the contents described in claim 1,
By cooling the liquefied fuel return pipe by the cooling means on the outer peripheral portion, when the liquefied fuel returns to the fuel tank, re-vaporization in the liquefied fuel return pipe can be suppressed.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment
An embodiment will be described with reference to FIGS.

As shown in FIG. 1, in the fuel vapor control apparatus according to the present embodiment, one end of an inlet pipe (fuel filling pipe) 12 penetrates a side wall of a fuel tank 10,
The end of the inlet pipe 12 is inserted into the fuel tank 10. The other end of the inlet pipe 12 reaches a fuel supply port 14 provided in a side wall of the vehicle.

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. . During refueling, when the fuel level in the inlet pipe 12 rises and a sensor provided on the refueling gun detects a full state, refueling from the refueling gun is automatically stopped. Further, a lid lid open / close detection switch 20 for detecting the opening / closing of the fuel lid 18 is provided in the fuel lid 18, and the lid lid open / close detection switch 20 is connected to a control circuit 22. In addition, inlet pipe 1
2 is provided with a ventilation pipe 24, and the control circuit 22 is also connected with a well-known fuel lid opener switch 23.

The fuel tank 10 has a two-layer tank structure including an inner tank shell 26 for storing fuel and an outer tank shell 28 disposed outside the inner tank shell 26. A heat insulating material 30 is provided between the tank shell 26 and the outer tank shell 28. The heat insulating material 30 makes it difficult for heat outside the fuel tank 10 to be transmitted to the inside of the fuel tank 10.

In the fuel tank 10, there are provided a float valve (cutoff valve) 31 for full tank detection and a float valve 32 for roll-over.
A vapor line 36 leading to a canister 34 is connected to 1 and 32.

In the middle of the vapor line 36, a cooler 4
8 are provided. The cooler 48 is connected to the control circuit 22, and the cooler 48 is controlled to be turned on and off by the control circuit 22.

As shown in FIG. 2, inside the cooler 48, a cooling section 48A using a Peltier element and a fuel storage section 4 connected to the cooling section 48A and an opening 48B are provided.
8C is formed. Exit 48D of fuel storage unit 48C
Is provided with a solenoid valve 49 as a control valve, and the solenoid valve 49 is connected to the control circuit 22.

As shown in FIG. 1, the control circuit 22 closes the solenoid valve 49 when it is determined that refueling is being performed based on an output signal from the lid lid open / close detection switch 20 or the fuel lid opener switch 23. To hold the liquefied fuel.

A liquefied fuel return pipe 52 is connected to the solenoid valve 49.
One end 52A of the liquefied fuel return pipe 52 is connected to the other end 52B of the liquefied fuel return pipe 52 in the vicinity of a fuel pump 54 disposed in the fuel tank 10, and in the present embodiment, in the vicinity of a suction filter 54A. Has been reached.

As shown in FIG. 3, the liquefied fuel return pipe 52
Is provided with an outer pipe 53 as a cooling means on the outer peripheral portion, and has a double pipe structure. Further, a thin tube 53B and a thin tube 53C are connected to one end 53A of the outer tube 53.

As shown in FIG. 2, the capillary 53B and the capillary 5
3C is connected to the cooling section 48A, and the other end of the outer pipe 53, that is, the end on the fuel pump 54 side is closed. Therefore, as shown by an arrow W in FIG. 2, the outer periphery of the liquefied fuel return pipe 52 is supplied with cool air from the cooling unit 48A through the outer pipe 53.

As shown in FIG. 1, the canister 34 is connected to a surge tank 74 communicating with an air cleaner 72 by a purge line 70.
A D-VSV (vacuum switching valve) 76 is provided at an intermediate portion of. Thereby, for example, utilizing the negative pressure generated by opening and closing the throttle valve, etc.,
The vapor in the fuel tank 10 can be drawn into the canister 34. The canister 34 has
An atmosphere valve 76 is provided.

A sub-tank 80 is provided inside the fuel tank shell 10. The fuel pump 54 is disposed inside the sub tank 80, and the fuel pump 54
Has a fuel supply pipe 84 leading to an injector 83 of the engine.
Are connected.

Next, the operation of the present embodiment will be described.

In the evaporative fuel control device of the present embodiment, when the vapor in the fuel tank 10 passes through the vapor line 36, a cooler 48 provided at an intermediate portion of the vapor line 36 is turned on by the control circuit 22. Therefore, the liquefied fuel liquefied in the cooling section 48A of the cooler 48 is supplied to the opening 4
The fuel storage unit 48C passes through 8B. At this time, if the fuel is not being refueled, the liquefied fuel passes through the solenoid valve 49 and is stored in the fuel storage section 48C because the solenoid valve 49 disposed at the outlet 48D of the fuel storage section 48C is opened by a signal from the control circuit 22. The fuel enters the liquefied fuel return pipe 52 from the portion 48C, flows through the liquefied fuel return pipe 52, and is returned into the fuel tank 10 from near the suction filter 54A of the fuel pump 54.

As a result, the liquefied fuel returned to the fuel tank 10 is sucked by the fuel pump 54 before being vaporized again, so that re-vaporization of the liquefied fuel in the fuel tank 10 can be suppressed.

On the other hand, during refueling, the control circuit 22 determines that refueling is in progress and closes the solenoid valve 49, so that the liquefied fuel is held in the fuel storage unit 48C. As a result, during refueling, the fuel pump 54 stops, but the liquefied fuel is
C and is not returned into the fuel tank 10. For this reason, even during refueling, re-vaporization of the liquefied fuel in the fuel tank 10 can be suppressed.

In the present embodiment, the liquefied fuel return pipe 5
2 has an outer tube 53 and has a double tube structure,
As shown by the arrow W in FIG. 2, cool air from the cooling unit 48 </ b> A is supplied to the outer peripheral portion of the liquefied fuel return pipe 52 through the outer pipe 53. As a result, when the liquefied fuel return pipe 52 is cooled by the cool air from the cooling unit 48A, it is possible to suppress the liquefied fuel from being re-vaporized in the liquefied fuel return pipe 52 when returning to the fuel tank 10.

Next, a second embodiment of the fuel vapor control apparatus according to the present invention will be described with reference to FIG.

The same members as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

As shown in FIG. 4, in the present embodiment, the cooling section 48A of the cooler 48 and the fuel storage section 90 are separate bodies, and both are connected by a connecting pipe 90.

Therefore, in this embodiment, in addition to the functions and effects of the first embodiment, the cooling unit 4 in the cooler 48
Since the fuel storage unit 8A and the fuel storage unit 90 are separately provided, even in a small vehicle or the like in which a wide mounting space cannot be secured, the cooling unit 48A and the fuel storage unit 90 can be divided and mounted in narrow mounting parts.

In the above, the present invention has been described in detail with respect to a specific embodiment. However, the present invention is not limited to the above embodiment, and various other embodiments are included within the scope of the present invention. It is clear to a person skilled in the art that is possible.

For example, in each of the above-described embodiments, the outer pipe 53 as a cooling means is provided on the outer peripheral portion of the liquefied fuel return pipe 52. , For example, urethane, PE foam, PP beads, etc. may be provided.

[0036]

According to the first aspect of the present invention, there is provided an evaporative fuel control apparatus for cooling evaporative fuel generated in a fuel tank by a cooler disposed upstream of a canister. Since the liquefied fuel return pipe is provided near the fuel pump incorporated in the fuel tank, the liquefied fuel can be prevented from being re-vaporized in the fuel tank.

According to a second aspect of the present invention, in the evaporative fuel control apparatus according to the first aspect, a fuel storage unit for holding the liquefied fuel liquefied by the cooler, and the fuel storage unit is disposed at an outlet of the fuel storage unit and is closed. And the control valve for holding the liquefied fuel in the fuel storage unit by performing the above operation. Therefore, in addition to the effect of claim 1, it is possible to suppress the re-vaporization of the liquefied fuel in the fuel tank even during refueling. Has the effect.

According to a third aspect of the present invention, in the evaporative fuel control device according to the first aspect, the liquefied fuel return pipe has a cooling means on an outer peripheral portion. There is an excellent effect that re-vaporization of the liquefied fuel in the fuel return pipe can be suppressed.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram illustrating an evaporative fuel control device according to a first embodiment of the present invention.

FIG. 2 is an enlarged sectional view showing a cooler of the evaporative fuel control device according to the first embodiment of the present invention.

FIG. 3 is an enlarged perspective view showing a liquefied fuel return pipe of the evaporated fuel control device according to the first embodiment of the present invention.

FIG. 4 is a schematic configuration diagram illustrating an evaporative fuel control device according to a second embodiment of the present invention.

FIG. 5 is a schematic configuration diagram showing a conventional evaporative fuel control device.

[Explanation of symbols]

 Reference Signs List 10 fuel tank 20 lid open / close detection switch 22 control circuit 34 canister 36 vapor line 48 cooler 48A cooler cooling unit 48B cooler opening 48C cooler fuel storage unit 48D cooling unit outlet 49 solenoid valve (control valve) 52 Liquefied fuel return pipe 53 Outer pipe (cooling means) 54 Fuel pump 54A Fuel pump suction filter 90 Fuel storage unit

Claims (3)

[Claims] 1. An evaporative fuel control device for cooling evaporative fuel generated in a fuel tank by a cooler disposed upstream of a canister, wherein the liquefied fuel liquefied by the cooler is contained in the fuel tank. An evaporative fuel control device having a liquefied fuel return pipe returning to the vicinity of the pump. 2. A fuel storage unit for holding liquefied fuel liquefied by the cooler, a control valve disposed at an outlet of the fuel storage unit, and closed to hold the liquefied fuel in the fuel storage unit. The evaporative fuel control device according to claim 1, comprising: 3. The evaporative fuel control device according to claim 1, wherein the liquefied fuel return pipe has cooling means on an outer peripheral portion.