JPH05950U - Fuel vapor emission control device - Google Patents

Abstract

(57) [Summary] [Structure] A two-way valve 6 and a solenoid valve 8 are provided in parallel in a fuel vapor passage 4 from a fuel tank 2 to a canister 3, and the solenoid valve 8 is opened when the engine 1 is operated. In the emission control device, a negative pressure control valve 11 is provided in parallel with the two-way valve 6 and in a position in series with the solenoid valve 8 and is operated to the closing side by a predetermined intake negative pressure or more acting from the engine 1 side. [Effect] Even if the drain port 3a of the canister 3 is blocked for some reason, the fuel tank 2 can be prevented from being deformed by the negative pressure of the engine intake air, and the amount of vapor generated due to the abnormal decrease in the tank internal pressure can be prevented from increasing. At the same time, deterioration of the canister due to a decrease in the purge amount of the canister 3 can be prevented.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a fuel vapor emission control device for an automobile.

[0002]

[Prior Art]

 First, FIG. 6 shows a conventional basic example of a system configuration of a fuel vapor emission control device, 1 is an engine, 2 is a fuel tank, 3 is a canister filled with a fuel vapor adsorbent (activated carbon), and 4 is a fuel tank 2. A fuel vapor passage between the canister 3 and the canister 5, a fuel vapor passage between the canister 3 and the engine 1, and a two-way valve 6. The two-way valve 6 is provided in the fuel vapor passage 4 between the fuel tank 2 and the canister 3. Specifically, as shown in FIG. 7, in the valve case 6a, the conduit 6b on the fuel tank 2 side is provided. A diaphragm 6d and a spring 6e that allow the flow from the canister 3 side to the pipeline 6c, and a valve body 6g and a spring 6h that are provided in the parallel path 6f of the pipeline 6c and allow the flow from the canister 3 side. It becomes.

Further, as is known from Japanese Utility Model Laid-Open No. 1-124361, there is a fuel vapor passage from a fuel tank to a canister which is provided with a solenoid valve which is closed after the engine is stopped. As shown in FIG. 8, a technique is also known in which a solenoid valve 8 that opens when the engine 1 operates is provided in a parallel path 7 with the 2-way valve 6.

[0004]

[Problems to be solved by the device]

 In the above conventional technique, when the inside of the canister 3 is being purged while the engine 1 is operating, if the drain port 3a of the canister 3 is blocked for some reason, the intake negative pressure of the engine 1 is reduced. There was a problem that all of them fell on the fuel tank 2, causing deformation of the tank 2 and deterioration of the canister due to a decrease in the purge amount of the canister 3.

Therefore, an object of the present invention is to provide a fuel vapor discharge control device having a solenoid valve in parallel with a two-way valve, which can prevent deformation of a fuel tank due to engine intake negative pressure and deterioration of a canister. Especially.

[0006]

[Means for Solving the Problems]

 In order to solve the above problems, the present invention provides a fuel vapor discharge control device in which a two-way valve and a solenoid valve are provided in parallel in a fuel vapor passage from a fuel tank to a canister, and a solenoid valve is opened when the engine is operating. In the above, a negative pressure control valve is provided in parallel with the two-way valve and in a position in series with the solenoid valve, the negative pressure control valve being actuated to the closing side by a predetermined intake negative pressure or more acting from the engine side. ..

[0007]

[Action]

 Even if the drain port of the canister is blocked, the negative pressure control valve installed in parallel with the 2-way valve and in series with the solenoid valve is closed due to the intake negative pressure above a certain level that acts from the engine side. Since it operates, the deformation of the fuel tank due to the negative pressure of the engine intake air is prevented, and the deterioration of the canister due to the reduction of the canister purge amount is also prevented.

[0008]

【Example】

 An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1 showing a system configuration of a fuel vapor discharge control device according to the present invention, as in the above, 1 is an engine, 2 is a fuel tank, 3 is a canister, 4 and 5 are fuel vapor passages, 6 is a 2-way valve, 7 is a parallel path, and 8 is a solenoid valve.

In this embodiment, in the parallel path 7, a negative pressure control valve 11 that is operated closer to the canister 3 side than the solenoid valve 8 by the intake negative pressure from the engine 1 side is operated. It is provided. In the first embodiment, as shown in FIG. 2, the negative pressure control valve 11 has a valve body 12 which is biased by a spring 13 to a retracted position toward the fuel tank 2 and is installed in the valve case 12. A throttle portion 16 is provided in the parallel passage 7 on the rod portion 15 side of 14.

When the inside of the canister 3 is being purged while the engine 1 is operating, the negative pressure control valve 11 is normally held open as shown in FIG. Is also sucked out to the engine 1 side. However, if the drain port 3a of the canister 3 is blocked for some reason, if a negative intake pressure from the engine 1 side that causes a large negative pressure in the fuel tank 2 acts, the negative pressure is generated. The pressure control valve 11 operates by the high flow rate passing through the throttle portion 16 so that the rod portion 15 of the valve body 14 closes the throttle portion 16 against the bias of the spring 13 as shown in FIG. And make small holes.

FIG. 3 shows a negative pressure control valve 21 according to a second embodiment. A diaphragm 25 and a spring 26 that allow a flow from a fuel tank side pipe line 23 to a canister side pipe line 24 in a valve case 22 are shown. Be equipped with. According to the negative pressure control valve 21, the diaphragm 25 closes the canister side pipe line 24 by the action of the intake negative pressure that largely reduces the pressure inside the fuel tank 2.

FIG. 4 shows a configuration example of the negative pressure control valve 31 integrated with the two-way valve. First, in the valve case 32, a chamber between the fuel tank side conduit 33 and the canister side conduit 34 is provided. 35 is provided, and a high pressure valve body 36 and a spring 37 for allowing a flow from the fuel tank side conduit 33 to the chamber 35 are provided, and the valve body 37 is connected to a rod 39 of a solenoid 38. A low pressure diaphragm 41 and a spring 42 that allow the flow from the chamber 35 to the canister side conduit 34 are provided, and a bypass passage 43 is provided between the fuel tank side conduit 33 and the canister side conduit 34. The bypass passage 43 is provided with a tank negative pressure preventing valve body 44 and a spring 45 that allow the flow from the canister side pipeline 34 to the fuel tank side pipeline 33.

Here, the illustrated position of the high pressure valve body 36 is in a state where the solenoid 38 is not energized, whereby the positive pressure side set pressure of the fuel tank is maintained at a high pressure (for example, 21 ± 4 mmHg). When the solenoid 38 is energized and the high pressure valve element 36 moves as shown by the arrow to open the fuel tank side conduit 33 to the chamber 35, the low pressure diaphragm 41 lowers the positive pressure side preset pressure of the fuel tank. For example, it can be switched to 10 mmHg or less).

FIG. 5 shows another configuration example of the negative pressure control valve 51 also integrated with a two-way valve. In the valve case 52, a flow from the fuel tank side pipe line 53 to the canister side pipe line 54 is allowed. A diaphragm 55 and a spring 56 are provided to connect the spring seat 57 to the rod 59 of the solenoid 58 and bypass the flow to allow flow from the canister side conduit 54 to the fuel tank side conduit 53. A pressure preventing valve element 61 and a spring 62 are provided. Here, the illustrated position of the spring seat 57 is in a state where the solenoid 58 is not energized, and the diaphragm 55 in which the stored pressure of the spring 56 is increased keeps the positive pressure side set pressure of the fuel tank at a high pressure and the solenoid 58. When the energization is turned on, the spring seat 57 moves as shown by the arrow in the figure, and the positive pressure side preset pressure of the fuel tank is switched to a low pressure by the diaphragm 55 in which the stored pressure of the spring 56 is weakened.

[0015]

[Effect of the device]

 As described above, according to the fuel vapor discharge control device of the present invention, the negative side valve is operated in parallel with the two-way valve and in series with the solenoid valve by the intake negative pressure above a predetermined level acting from the engine side. Since the pressure control valve is provided, even if the drain port of the canister is blocked, it is possible to prevent the fuel tank from being deformed due to the negative pressure of the engine intake air, and increase the amount of vapor generation due to the abnormal decrease in tank internal pressure. It is possible to prevent the deterioration of the canister due to the decrease in the canister purge amount.

[Brief description of drawings]

FIG. 1 is a system configuration diagram of a fuel vapor emission control device according to the present invention.

FIG. 2 is a diagram showing a configuration of a negative pressure control valve and an operation mode (a) and (b) in the first embodiment of the present invention.

FIG. 3 is a diagram showing a structure of a negative pressure control valve according to a second embodiment of the present invention.

FIG. 4 is a diagram showing a configuration example of a negative pressure control valve integrated with a two-way valve.

FIG. 5 is a diagram showing another example of the configuration of a negative pressure control valve that is also integrated with a two-way valve.

FIG. 6 is a system configuration diagram showing a basic example of a conventional fuel vapor emission control device.

FIG. 7 is a diagram showing a general configuration example of a 2-way valve.

FIG. 8 is a system configuration diagram showing a conventional example of a fuel vapor emission control device provided with a solenoid valve.

[Explanation of symbols]

1 ... Engine, 2 ... Fuel Tank, 3 ... Canister, 4 ...
Fuel vapor passage between fuel tank and canister, 5 ... Fuel vapor passage between canister and engine, 6 ... 2-way valve, 7 ... Parallel passage, 8 ... Solenoid valve, 11, 21
… Negative pressure control valve.

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Hideo Watanabe 1-4-1 Chuo, Wako City, Saitama Prefecture Honda R & D Co., Ltd.

Claims (1)

[Claims for utility model registration] 1. A fuel vapor discharge control device in which a two-way valve and a solenoid valve are provided in parallel in a fuel vapor passage from a fuel tank to a canister, and the solenoid valve is opened when the engine is operated. In the above, a negative pressure control valve is provided in parallel with the two-way valve and in series with the solenoid valve, the negative pressure control valve being operated to the closing side by a predetermined or more intake negative pressure acting from the engine side. Fuel vapor emission control device.