JPH03222855A - Evaporated gas prefiring restraint for fuel tank - Google Patents

Abstract

PURPOSE:To balance each pressure in and out of a fuel tank and eliminate any prefiring of evaporated gas at time of oil supplying by forming a bypass passage with a valve in an evaporation line of the fuel tank, and opening the valve as long as the specified time immediately after engine stoppage. CONSTITUTION:At time of engine driving, a solenoid valve 13 in a bypass pipe 11 is closed. Evaporated gas existing in an upper space 3 in a fuel tank 1 is passed through an evaporation pipe 4 and a check valve 5 and then guided to an inlet pipe 10a of a canister 10. On the other hand, at time of engine stoppage, a timer circuit 12 is operated and the solenoid valve 13 is opened as long as the specified time from immediately after the stoppage. With this constitution, positive pressure existing in the upper space 3 in the fuel tank 1 is set free into the atmosphere via a drain pipe 10c of the canister 10. Accordingly, even if a filler cap is removed, each pressure inside and the outside is balanced by the atmosphere, so that any blowout of the evaporated gas from a neck part 7 is thus eliminable.

Description

[Detailed Description of the Invention] a. Field of Industrial Application The present invention relates to a fuel tank for an automobile, and more particularly to a device for suppressing evaporated gas from blowing back into the fuel tank during refueling. .

b. Prior Art FIG. 4 shows the piping structure of a conventional general fuel tank 1. The upper space 3 of the fuel tank 1, into which fuel 2 such as gasoline is supplied, is connected to the evaporation pipe 4. It is communicated with a canister, etc. (not shown) via a check pulp 5 disposed in the middle. Further, the upper space 3 of the fuel tank 1 is communicated with the refueling neck part 7 of the fuel tank 1 via a vent vibro, so that when replenishing the fuel tank 1 with the fuel 2, the air in the fuel tank 1 is transferred to the atmosphere. configured to emit into the air.

C3 Invention aims to solve the problem In such a conventional general fuel tank 1, since the pressure inside the fuel tank 1 is positive pressure, the upper space is drained as soon as the filler cap 8 is removed during refueling. The evaporated gas (gasoline vapor) in the fuel tank I is blown back to the outside of the fuel tank l through the vent vibro and the refueling neck part 7, as shown by arrows A and B in FIG. 5, and is ejected in large quantities into the atmosphere. Sometimes. In such a case, vapor gas such as gasoline is a sensitive substance for humans, so if nearby refueling workers or the like directly inhale the vapor gas, it may have an adverse effect on their health. In addition, the ejection of steam gas is one of the causes of contaminating the natural environment and can sometimes cause a fire.

Therefore, in the past, in order to prevent steam gas from being directly inhaled by refueling workers, a two-stage motion opening mechanism of the filler canop 8 was adopted, or a valve or the like was used to slowly release the steam gas. There are already proposals to adopt a mechanism that releases the water to the outside.

However, in these methods, the filler camp 8
The reality is that there is no fundamental solution to preventing steam gas from blowing back when removing the pipe.

Additionally, a mechanism for releasing the pressure inside the fuel tank 1 by means of a valve linked to the opening and closing of the fuel lid is also available.
However, this mechanism has a major problem in that it cannot be applied to vehicles without fuel lint.

The present invention has been made in view of the above-mentioned 9-hole various actual situations, and its purpose is to provide a fuel tank at the start of refueling (when the filler cap is removed), regardless of the presence or absence of a fuel lid.
An object of the present invention is to provide an evaporative gas blowback suppressing device configured to suppress the ejection of harmful substances of evaporative gas (gasoline vapor, etc.) to the outside of a fuel tank.

d. Means for Solving the Problems In order to achieve the above-mentioned object, in the present invention, a bypass path is formed in the evaporation line connected to the upper space in the fuel tank, and this bypass path is opened and closed. An opening/closing means is provided, and the opening/closing means is configured to be open only for a certain period of time after the engine is stopped.

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2. Note that the same reference numerals are given to the parts in FIGS. 1 and 2 that are common to those in FIG. 4.

FIG. 1 shows the configuration of a vapor gas blowback prevention device for a fuel tank 1 of an automobile. As shown in FIG. 1, the upper space 3 of the fuel tank 1 is connected to the inlet pipe 10a of the canister 10 via an evaporation pipe 4, and a check valve 5 is disposed in the middle of the evaporation pipe 4. has been done. A bypass pipe 11 is formed in the evaporation pipe 4 to bypass the check valve 5, and a solenoid valve 13 whose opening and closing are controlled by a timer circuit 12 is disposed in the middle of the bypass pipe 11. has been done.

However, between the fuel tank l and the engine (not shown),
First evaporation line 14 consisting of evaporation pipe 4, check valve 5 and canister 10
and a second evaporation line (bypass path) 15 consisting of a bypass pipe 11 and a solenoid valve 13.
are provided for each. The out-left pipe 10b of the canister 10 described above is connected to a cab brake or the like (not shown).

Further, the solenoid valve 13 mentioned above is kept closed while the engine is running, and after the engine is stopped, it is kept open for a certain period of time T (see Figure 2) immediately after the engine is stopped by a timer circuit 12. It is configured.

The steam gas blowback prevention device configured as described above operates specifically as follows.

First, as shown in FIG. 2, while the engine is operating, the solenoid valve 13 is closed based on the engine operating switch being in the ON state. Therefore, the bypass pipe 11 does not function, and only the normal first evaporation line 14 functions. That is, in this case, the evaporative gas (gasoline vapor, etc.) existing in the upper space 3 of the fuel tank 1 passes through the evaporation pipe 4 and the check valve 5 as shown by the solid arrow C in FIG. It is guided to the inlet pipe 10a of the canister 10.

On the other hand, when the engine is stopped in response to the engine operation switch being switched to the OFF state, the timer circuit 12
is activated, and the solenoid valve 13 is opened for a certain period of time T immediately after the engine is stopped based on the control iI multiplied signal from the timer circuit 12. Along with this, as shown by the arrow in FIG. Since it escapes into the atmosphere, the pressure in the upper space 3 becomes equal to atmospheric pressure. Therefore, even if the filler camp 8 is removed and the fuel tank 1 is opened for refueling under this condition, the pressure of the evaporated gas in the fuel tank 1 and the pressure outside the vehicle will maintain equilibrium at atmospheric pressure. Therefore, it is possible to eliminate the ejection of evaporative gas from the fuel filler port of the neck portion 7.

Although one embodiment of the present invention has been described above, the present invention is not limited to the embodiment described above, and various modifications and changes can be made based on the technical idea of the present invention.

For example, in the embodiment described above, the bypass pipe 11 that bypasses the check valve 5 is connected to the second evaporative engine line 1.
5, but a bypass path 18 may be formed as shown in FIG. That is, a branch pipe 16 is provided that branches from the evaporation pipe 4 at the upstream portion of the check valve 5, and the end of the branch pipe 16 is connected to the in-left pipe 17a of the small canister 17 for refueling.
A solenoid valve 13 that is controlled to open and close may be provided, and the out-left pipe 17b of the small canister 17 may be connected to a carburetor, etc. In this case as well, the branch pipe 16, the solenoid valve 13 and the small canister 17 By providing a bypass path 18 and opening the solenoid valve 13 in conjunction with engine stoppage, the pressure in the upper space 3 of the fuel tank 1 can be brought to atmospheric pressure, thereby preventing steam gas from blowing back. It can be prevented.

e. Effects of the Invention As described above, the present invention forms a bypass path in the evaporation line of the fuel tank, and operates the opening/closing means (for example, the solenoid valve 13) disposed in the middle of the bypass path at a constant temperature after the engine is stopped. Since the fuel tank is configured to remain open for a certain period of time, after a certain period of time has passed since the engine has stopped, the pressure in the upper space of the fuel tank becomes atmospheric pressure and is in equilibrium with the external pressure. Even if the filler camp of the fuel tank is removed, it can prevent evaporated gas from blowing back to the outside.

Therefore, it is possible to prevent the risk of a refueling worker inhaling evaporated gas, which is a harmful substance, or a fire caused by an explosive gas, and to suppress environmental deterioration due to the release of harmful substances into the atmosphere. I can do it. Moreover, the present invention
Since it can be applied regardless of the presence or absence of fuel lint, it can be applied to various types of fuel #1 tanks and is very practical.

[Brief explanation of drawings]

Figures 1 and 2 show an embodiment of the present invention, in which Figure 1 is a schematic diagram of a fuel tank evaporative gas blowback suppression device, and Figure 2 is a diagram showing the relationship between the engine and the 7-noid hull. FIG. 3 is a schematic configuration diagram similar to FIG. 1 showing another embodiment of the present invention; FIG. 4 is a schematic configuration diagram showing a conventional fuel tank piping structure; FIG. 5 This is an enlarged view of the main parts of the same as above. l... fuel tank, 3... upper space, 4...
... Evaporation, IO... Canister, 11.
・・Bypass pipe, 12・・Timer circuit, 13・
... Solenoid valve also as an opening/closing means, 14... First evaporation line, 15... Second evaporation line (bypass path), 16... Branch pipe, 17... Small canister, 18...Bypass road. Patent applicant Suzuki Motor Co., Ltd. (and 2 others)

Claims (1)

[Claims] A bypass path is formed in the evaporation line connected to the upper space in the fuel tank, and an opening/closing means for opening and closing this bypass passage is provided, and the opening/closing means is kept open only for a certain period of time after the engine is stopped. A fuel tank evaporative gas blowback suppressing device characterized by comprising: