JP2529282Y2 - Fuel evaporation suppression device - Google Patents

Description

[Detailed description of the invention]

[0001]

In this invention, a canister for adsorbing evaporated fuel is provided in a passage connecting an upper space of a fuel tank and an intake pipe of an engine, and an internal pressure of the fuel tank is provided between the fuel tank and the canister in the passage. The present invention relates to a fuel evaporation suppression device including a two-way valve that opens when the atmospheric pressure exceeds a predetermined value and opens when the internal pressure falls below a predetermined value.

[0002]

2. Description of the Related Art Such a fuel evaporation suppressing device is known, for example, from JP-A-55-154251.

In such a fuel evaporation suppressing device, when the inside of the fuel tank is pressurized by the valve opening pressure set in the two-way valve, the filler cap of the fuel tank is removed to supply the fuel. The internal fuel vapor may be released to the atmosphere from the fuel supply port at the time. In order to avoid such inconvenience, the conventional fuel evaporation suppression device described in the above publication discloses an on-off valve provided in parallel with the two-way valve, simultaneously removing the filler cap of the fuel tank and opening the valve to invalidate the two-way valve, The internal pressure of the fuel tank is reduced to atmospheric pressure to prevent fuel vapor from being released from the fuel supply port into the atmosphere.

[0004]

However, in the conventional fuel evaporation suppressing device, when the fuel is supplied to the fuel tank by the refueling gun, the fuel flows into the canister through the open / close valve which is in an open state. May be impaired.

The present invention has been made in view of the above-mentioned circumstances, and it is possible to prevent leakage of fuel vapor when the filler cap of the fuel tank is opened, and there is no possibility that fuel will flow into the canister during refueling. It is an object to provide a fuel evaporation suppressing device.

[0006]

According to the present invention, a canister for adsorbing fuel vapor is provided in a passage connecting an upper space of a fuel tank and an intake pipe of an engine, and a fuel tank in the passage is provided. And a canister between the fuel tank and the canister. A two-way valve opens when the internal pressure of the fuel tank exceeds a predetermined value above the atmospheric pressure, and opens when the internal pressure falls below a predetermined value. In the device, in the passage connecting the fuel tank and the canister,
A normally open on-off valve that can be closed when fuel is supplied to the fuel tank is connected in parallel with the two-way valve.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

As shown in the figure, an air cleaner 2, a fuel supply device 3, and a throttle valve 4 are provided in an intake pipe 1 of an internal combustion engine E, and fuel in a fuel tank T is supplied with fuel supply pipes 5 ₁ , 5. _The fuel is supplied to the fuel supply device 3 by a fuel pump 6 interposed in ₂ .

[0009] The intake pipe 1 and the upper space of the fuel tank T are connected by a pipe _71, 7 _2, 7 ₃ for the canister, along with two-way valve 8 between the pipe 7 _1, 7 ₂ is interposed, A canister 9 is provided between the pipes 7 ₂ and 7 _3.
Is interposed.

The two-way valve 8 has a structure in which two relief valves are combined. When the internal pressure of the fuel tank T exceeds the atmospheric pressure by a predetermined value, and when the internal pressure of the fuel tank T drops by a predetermined value below the atmospheric pressure. The fuel tank T and the canister 9 are communicated with each other. Further, the canister 9 in which housing the activated carbon between the upper and lower filter, together with the passage 7 ₂ is open to the inside of the activated carbon, the passage 7 ₃ is opened to the upper space of the upper filter, the further lower the filter lower space communicates with the atmosphere through the air opening 9 _1.

[0011] two-way other pipe 7 _4, 7 ₅ are branched from the pipe _71, 7 ₂ extending around the valve 8, in which the pipes 7 _4, 7 between ₅ is connected to the control device 10 solenoid The driven on-off valve 11 is interposed. That is, the two-way valve 8 and the on-off valve 11 are provided in parallel between the fuel tank T and the canister 9. In the normal state, the on-off valve 11 is kept open. For example, the filler cap 13 is opened by the output signal of a sensor that detects the attachment or detachment of the filler cap 13 provided at the upper end of the fuel supply pipe 12 of the fuel tank T. The valve is controlled to be closed during the supply of the removed fuel.

Next, the operation of the embodiment of the present invention having the above configuration will be described.

In a normal state in which the filler cap 13 of the fuel tank T is closed, the switching valve 11 is in an open state, the two-way valve 8 does not substantially function, and the fuel tank T and the canister 9 are connected to the pipe 7. _1, 7 _4-off valve 11 opened, and communicate with each other via the pipe 7 _5, 7 _2. Therefore, when the temperature of the fuel tank T rises and the internal fuel evaporates, the fuel vapor reaches the canister 9 from the on-off valve 11 and is adsorbed by the activated carbon, thereby preventing the fuel vapor from leaking to the outside. This internal pressure of the fuel tank T at the same time is released to the outside from the air vent port 9 ₁ of the canister 9, the pressure increase inside the fuel tank T is prevented. When the temperature of the fuel tank T decreases, outside air is introduced into the inside of the fuel tank T through a route reverse to that described above, thereby preventing a negative pressure from being generated inside the fuel tank T. For more during the operation of the internal combustion engine E which is a negative pressure in the intake pipe 1 occurs, air pipes 7 introduced from the air vent port 9 ₁ of the canister 9
₃ and is sucked into the intake pipe 1 through the canister 9
The fuel vapor adsorbed on the activated carbon is purged and supplied to the intake pipe 1.

As described above, the internal pressure of the fuel tank T is always maintained at the atmospheric pressure by the operation of the normally open on-off valve 11, so that even if the filler cap 13 is removed to supply the fuel to the fuel tank T, the fuel is not removed. The fuel vapor inside the tank T is prevented from being released from the fuel supply pipe 12 to the outside.

The filler cap 1 of the fuel tank T
When the controller 3 is removed, the control device 10 closes the on-off valve 11, so that the fuel tank T and the canister 9 communicate with each other via the two-way valve 8. Since the two-way valve 8 does not open until the internal pressure of the fuel tank T exceeds a preset pressure, the fuel inside the fuel tank T is blocked by the two-way valve 8 when fuel is supplied to the fuel tank T by the refueling gun. And is prevented from flowing into the canister 9.

Thus, even if the valve opening pressure of the two-way valve 8 is set to be high to enhance the above-described effect, the fuel tank T and the canister 9 are normally communicated by the on-off valve 11, and the internal pressure of the fuel tank T is large. Since the pressure is maintained at the atmospheric pressure, leakage of fuel vapor from the seal portion of the fuel tank T can be reduced.

In this embodiment, the on / off valve 11 is operated by detecting the attachment / detachment of the filler cap 13 of the fuel tank T. However, the on / off valve 11 can be operated by detecting the opening / closing of the filler lid. .

[0018]

As described above, according to the present invention, in a normal state in which fuel is not supplied to the fuel tank, the open / close valve bypassing the two-way valve is opened, and the internal pressure of the fuel tank is always set to the atmospheric pressure. This not only reduces the leakage of fuel vapor from the fuel tank seal, but also removes the fuel vapor inside the fuel tank when the fuel tank filler cap is removed for fuel supply. The disadvantage of being released to the atmosphere at an internal pressure of 2.times. In addition, when fuel is supplied to the fuel tank, the on-off valve closes and the two-way valve functions, so that the inconvenience of fuel in the fuel tank flowing into the canister can be avoided.

[Brief description of the drawings]

FIG. 1 is a diagram showing a fuel evaporation suppressing device according to an embodiment of the present invention;

[Explanation of symbols]

 8 ... two-way valve 9 ... canister 11 ... on-off valve E ... engine T ... fuel tank

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-130254 (JP, A) JP-A-61-53451 (JP, A) JP-A-55-154251 (JP, A) 160764 (JP, U)

Claims (1)

(57) [Scope of request for utility model registration] A canister (9) for adsorbing evaporated fuel is provided in a passage connecting an upper space of a fuel tank (T) and an intake pipe (1) of an engine (E), and a fuel tank (T) in said passage is provided. Fuel tank (T) between canisters (9)
In a fuel evaporation suppression device including a two-way valve (8) that opens when the internal pressure of the fuel cell exceeds the atmospheric pressure by a predetermined value and opens when the internal pressure falls below the atmospheric pressure by a predetermined value, A normally open on-off valve (11) that can be closed when fuel is supplied to the fuel tank (T) is connected in parallel with the two-way valve (8) to the passage connecting the tank (T) and the canister (9). A fuel evaporation suppressing device characterized by the above-mentioned.