JP7401190B2 - Check valve for purge passage - Google Patents

Description

The present invention relates to a check valve disposed in a purge passage connected to a fuel tank and an intake system in a vehicle.

In vehicles equipped with internal combustion engines, damage to the fuel tank is prevented by letting vaporized fuel in the fuel tank escape into the intake system through a purge passage. A storage canister and a check valve for pressure regulation are arranged such that the check valve is located on the fuel tank side (upstream side) and the canister is located on the intake side (downstream side).

The structure of the check valve placed in the purge passage varies, but in any case, it is equipped with an inlet port that is connected to the fuel tank via a tube, and an outlet port that is connected to the canister via a tube. , an inlet port is provided at the top of the body and an outlet port is provided at the bottom of the body.

Regarding the orientation of the inlet port and the outlet port, for example, in Patent Document 1, the inlet port and the outlet port are in opposite orientations, and in Patent Document 2, the inlet port and the outlet port are in a parallel orientation. Furthermore, in Patent Document 3, the inlet port and the outlet port are in a perpendicular posture.

Japanese Patent Application Publication No. 2011-141018 Microfilm of Utility Model No. 61-161483 Microfilm of Utility Model No. 57-112176

In each of these publicly known examples, it is not clear in what position the check valve is actually installed in the vehicle, but if the canister is placed below the check valve, the check valve can The vaporized fuel that has accumulated in the tube connecting the canister and the canister may condense and liquefy while the engine is stopped, and then freeze, blocking the tube. As a result, the vaporized fuel does not flow into the canister and the internal pressure of the fuel tank increases. There was a risk that the fuel tank would be damaged.

Regarding this point, it would be better to install an auxiliary tank to store the liquefied fuel between the check valve and the canister, but this would not only increase the number of parts and cost, but also increase the number of tubes and connection points. This is also unfavorable from a safety standpoint.

The present invention was made based on this knowledge, and is intended to prevent the purge passage from being blocked due to freezing of vaporized fuel with a simple structure.

The present invention relates to a check valve, and this check valve includes:
"It has an inlet port that is connected to the fuel tank via a tube, and an outlet port that is connected to the canister via a tube, and a lower part that can store liquefied fuel is located below the outlet port. In a configuration where a buffer space is formed,
an upper cap having the inlet port, a lower cap having the outlet port, and an intermediate member sandwiched between the upper cap and the lower cap; A passage communicating with the port is formed,
and the lower buffer space is formed by lowering the inner bottom surface of the lower cap below the outlet port.

In the present invention, there are no limitations on the orientation of the inlet port and the outlet port, but both ports are preferably oriented sideways or upwards. Further , the tube described in this application has the same meaning as a conduit, and includes a tube made of metal.

While fuel vaporization occurs in the fuel tank, the canister has a large capacity, so even if liquefied fuel freezes inside the canister, there is no problem of passage blockage. On the other hand, when the fuel is vaporized, the vaporized fuel passes through the check valve, so the fuel hardly liquefies or freezes in the tube connecting the check valve and the fuel tank. Problems due to freezing of liquefied fuel therefore appear particularly between the check valve and the canister.

In the present invention, since the lower buffer space is formed at a lower position than the outlet port of the lower cap , the liquefied fuel generated in the tube connecting the check valve and the canister can be stored in the lower buffer space of the lower cap . However, even if the liquefied fuel freezes in the buffer space under the lower cap , it does not block the passage, so there is no problem with the passage of the vaporized fuel. Therefore, the function of the check valve can be activated to prevent the internal pressure of the fuel tank from rising abnormally and causing damage to the fuel tank.

In addition, since the lower buffer space is formed in the lower cap of the check valve, there is no increase in the number of parts, which can reduce costs, and there is no need to increase the number of tubes or connection points, so there are no safety issues. do not have. Therefore, according to the present invention, damage to the fuel tank due to freezing of the liquefied fuel can be prevented without increasing costs or causing safety problems.

Now, since vaporized fuel is sent from the canister to the intake system, in order to send the vaporized fuel smoothly from the canister to the intake system, it is preferable to arrange the canister at a high position in the engine room. On the other hand, the purge tube connected to the fuel tank passes through the bottom of the car body and is led out into the engine room, so it is reasonable to install the check valve below the canister to make the purge tube as short as possible. It is.

In this regard, in the present invention, even if the check valve is located at a lower position than the canister, the liquefied fuel generated in the tube connecting the canister and the check valve can be stored in the buffer space below the check valve , so the purge tube It is possible to prevent damage to the fuel tank due to freezing of the fuel while keeping the time period as short as possible. In this case, since the height position of the check valve can be set arbitrarily, the flexibility in the mounting position of the check valve can be improved.

If the outlet port is formed in a position perpendicular to the axis of the body as in the embodiment, the height can be suppressed while forming a lower buffer space in the lower cap , which has the advantage of making the check valve more compact. .

FIG. 3 is a diagram of the arrangement viewed from the horizontal direction. FIG. 3 is a longitudinal cross-sectional view of the check valve.

Next, embodiments of the present invention will be described based on the drawings. FIG. 1 shows the appearance and arrangement of the check valve 1, and FIG. 2 shows a longitudinal section. The check valve 1 is made of synthetic resin and has a body composed of a cylindrical intermediate member 2, an upper cap 3 fixed to the upper part of the intermediate member 2, and a lower cap 4 fixed to the lower part of the intermediate member 2. A horizontal inlet port 5 is integrally formed in the upper cap 3, and a horizontal outlet port 6 is integrally formed in the lower cap 4.

The inlet port 5 and the outlet port 6 are formed into a cylindrical shape so that the tubes 7 and 8 can be fitted therein, but they may also be in the form of holes into which a joint can be inserted or screwed. Also, although the inlet port 5 and the outlet port 6 are oriented in the same direction, they can also be oriented in different directions. It is also possible to have the inlet port 5 facing upward and the outlet port 6 facing sideways.

The upper cap 3 and the lower cap 4 are each fixed to the intermediate member 2 by welding or forced fitting. Although not shown, it is preferable to provide a sealing material on the overlapping surfaces of the upper cap 3 and the lower cap 4 and the intermediate member 2.

In the intermediate member 2, a feed passage 9 through which vaporized fuel flows downward and a return passage 10 through which vaporized fuel flows upward are formed so as to open on both upper and lower sides, respectively. The lower half of the feed passage 9 has a large diameter section 9a, and a first ball 11 and a first spring 12 that biases the ball from below are arranged in the large diameter section 9a. On the other hand, the return passage 10 has a large diameter section 10a in its upper half, and a second ball 13 and a second spring 14 that biases the second ball 13 from above are arranged in the large diameter section 10a.

An upper and lower buffer space 15 is formed in the upper part of the intermediate member 2 and communicates with the inlet port 5 and both passages 9 and 10. Further, the upper cap 3 is provided with an upper spring receiver 16 that projects downward and holds the second spring 14 so that it cannot be displaced laterally. Note that the upper buffer space 15 may be formed in the upper cap 3 or may be formed in a state spanning both the upper cap 3 and the intermediate member 2. Further, the upper spring receiver 16 may be a recess instead of a protrusion.

The lower cap 4 has a lower buffer space 17 whose inner bottom surface is lowered below the outlet port 6, and a lower buffer space 17 that holds the first spring 12 so as not to shift laterally is formed on the inner bottom surface of the lower buffer space 17. A spring receiver 18 is formed. This lower spring receiver 18 may also be a recess instead of a protrusion.

The starting end of the first tube 7 connected to the inlet port 5 is connected to a fuel tank (not shown). On the other hand, the terminal end of the second tube 8 connected to the outlet port 6 is connected to the inlet port 20 of the canister 19 . A third tube 22 is connected to the outlet port 21 of the canister 19 for sending vaporized fuel to the intake system.

The entire canister 19 is located at a higher position than the outlet port 6 of the check valve 1, but at least the inlet port 20 of the canister 19 may be located at a higher position than the outlet port 6 of the check valve 1.

In the above configuration, when the internal pressure of the fuel tank increases, the vaporized fuel pushes down the first ball 11 and flows from the feed passage 9 toward the canister 19. This can prevent the internal pressure of the fuel tank from becoming excessively high. Conversely, if the internal pressure of the fuel tank decreases or the pressure downstream of the check valve 1 increases for some reason, the vaporized fuel pushes up the second ball 13 and flows toward the first tube 7. In this way, the pressure in the purge passage is regulated.

In a cold environment such as winter, the liquefied fuel accumulated in the tubes 7 and 8 may condense and become liquefied, and these liquefied fuels flow down to the lower buffer space 17 and accumulate there. Even if the liquefied fuel 23 accumulated in the lower buffer space 17 freezes, the lower buffer space 17 has sufficient volume and the outlet port 6 and both passages 9 and 10 are in communication with each other, so that the internal pressure of the fuel tank When the liquefied fuel rises, the liquefied fuel can be released into the canister 19. Therefore, damage to the fuel tank can be prevented.

Further, since the lower buffer space 17 is integrally formed with the lower cap 4, there is no increase in the number of parts, and costs can be reduced accordingly.

If the outlet port 6 is formed in the lower cap 4 in a horizontal position as in the embodiment, the planar area of the lower buffer space 17 of the lower cap 4 can be increased. Therefore, a sufficient volume of the lower buffer space 17 can be secured, and the storage function of the liquefied fuel 23 can be ensured. There is also the advantage that the check valve 1 can be made more compact. If the inlet port 5 is formed laterally as in the embodiment, compactness can be further promoted.

The intermediate member 2 can be manufactured using a simple mold device in which a pair of molds are brought into close contact and separated. Further, the upper cap 3 and the lower cap 4 can be easily manufactured using a mold device equipped with slide pins that form the insides of the ports 5 and 6. Therefore, there are no manufacturing problems.

The present invention can be embodied in various ways other than the illustrated form. For example , the valve mechanism can be implemented in various ways other than the illustrated structure.

The present invention can be embodied in a check valve for a vehicle purge passage. Therefore, it can be used industrially.

1 Check valve 2 Intermediate member forming the body 3 Upper cap forming the body 4 Lower cap forming the body 5 Inlet port 6 Outlet port 7 First tube connected to the fuel tank 8 Second tube connected to the canister 9 Feed passage 10 Return passage 11, 13 Ball as an example of a valve body 12, 14 Spring 15 Upper buffer space 17 Lower buffer space 19 Canister

Claims (1)

It has an inlet port connected to the fuel tank via a tube, and an outlet port connected to the canister via a tube, and a lower buffer capable of storing liquefied fuel is located below the outlet port. A check valve for a purge passage in which a space is formed,
an upper cap having the inlet port, a lower cap having the outlet port, and an intermediate member sandwiched between the upper cap and the lower cap, the intermediate member having the inlet port and the outlet port. A passageway is formed that communicates with the
and the lower buffer space is formed by lowering the inner bottom surface of the lower cap below the outlet port.
Check valve for purge passage.

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