JPH0450450Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a technology for preventing fuel gas from leaking into a mixer after the engine is stopped, using a shutoff valve in a fuel supply system for a gas fuel engine.

[Assumption structure]

The basic structure for preventing fuel gas from leaking into the mixer after the gas fuel engine is stopped is as shown in FIG. 1 or 3, for example, as follows.

That is, the cutoff valve 9 is closed when there is no intake negative pressure downstream of the throttle valve 4 in the intake passage 7 of the mixer 1 in the gas fuel supply passage 6 from the gas supply source 5 to the fuel suction port 8 of the mixer 1. It is configured by providing.

[Prior art]

In the above-mentioned structure, in the prior art, as shown in FIG. 3, the cutoff valve 9 is interposed in the middle of the gas supply pipe connecting the regulator 24 and the mixer 1. (Approximate material: Jikko Sho 40-9204
(No. Publication) [Problems to be solved by the invention] The above-mentioned conventional technology has the following problems.

(a) The regulator 24 and the shutoff valve 9 are connected to the mixer 1
A total of a gas supply pipe that connects the regulator 24 and the cutoff valve 9, a gas supply pipe that connects the cutoff valve 9 and the mixer 1, and a negative pressure guide pipe that connects the mixer 1 and the cutoff valve 9. Because it requires three pipes and six pipe joints,
The piping structure is complicated and expensive.

(b) The above three pipes, the shutoff valve 9 as an independent component,
The space required for each of these parts increases to the extent that a support device for the shutoff valve 9 is required, making the engine large. Moreover, it increases manufacturing costs.

[Means to solve the problem]

In the above-mentioned premise structure, the present invention provides, for example, the first
As shown in the figure, the cutoff valve 9 is characterized in that it is configured as follows.

That is, the fuel suction port 8 of the mixer 1
A negative pressure drive part 12 of the cutoff valve 9 is provided in the mixer part on the opposite side, and the stem 11, which is driven forward and backward by the negative pressure drive part 12 of the cutoff valve 9, is thrust into the bench lily part 2 in the mixer 1. In this bench lily portion 2, a valve member 10 provided at the tip of a stem 11 is configured to face the fuel suction port 8 of the mixer 1 so as to be openable and detachable.

[Effect of idea]

Since the present invention is configured as described above, it has the following effects.

(b) Since the shutoff valve is installed in a part of the mixer, the negative pressure guide path connecting this shutoff valve and the regulator is
It can be formed with holes drilled in the mixer and isolation valve, eliminating the need for pipes.

Then, it is only necessary to connect the regulator and the mixer with one gas supply pipe.

As a result, in order to connect the regulator and the shutoff valve to the mixer, the conventional technology required three pipes and six pipe joints, whereas the present invention requires one third of the pipe joints. pipe and 2
The number of pipe joints can be reduced to a number of pipe joints, which greatly simplifies the piping structure and makes it cheaper.

(b) Since the cutoff valve is provided in a part of the mixer, the main body of the cutoff valve can also be used as a part of the mixer main body, and the structure can be simplified.

Furthermore, since the valve member of the shutoff valve faces the fuel suction port of the mixer so that it can be opened and closed, the valve seat and the valve inlet hole, which are opened and closed by this valve member, are also used as the fuel suction port of the mixer. can be simplified.

Thereby, the total structure of the mixer and the shutoff valve can be simplified and downsized.

(c) As mentioned above, the total structure of the mixer and shutoff valve can be simplified and downsized.

Since the shutoff valve is integrated into the mixer, a support device for the shutoff valve can be omitted.

Furthermore, the number of pipes required to fluidly connect the regulator and the shutoff valve to the mixer can be reduced from three to one.

By combining these three factors, the space required for each component such as the shutoff valve and piping is reduced, allowing the engine to be made smaller. Furthermore, manufacturing costs can also be reduced.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

FIG. 1 is a vertical cross-sectional view of a main part of an embodiment of the present invention, and FIG. 2 is a front view of an interlocking mechanism between a throttle valve and a choke valve.

The mixer 1 connected to the gas fuel engine E is
It is equipped with a bench lily section 2 through which intake air passes, a choke valve 3 upstream thereof, and a throttle valve 4 downstream thereof. A fuel suction port 8 for discharging fuel into the fuel tank 7 is opened on the circumferential surface of the bench lily part 2.

This fuel suction port 8 is provided with a shutoff valve 9 that moves forward and backward toward the fuel suction port 8 . This shutoff valve 9 includes a valve member 10 that approaches and separates from the fuel suction port 8, and a stem 11 that is airtightly supported on a portion of the peripheral wall of the bench lily portion 2 that opposes the fuel suction port 8 so as to be movable back and forth.
and a negative pressure drive section 12 connected to this stem 11.
Equipped with. The negative pressure drive unit 12 includes an atmospheric pressure receiving chamber 13 that is open to the atmosphere, and an intake negative pressure receiving chamber 1 that is connected to the downstream side of the throttle valve 4 of the intake path 7.
4, a diaphragm 15 that partitions both pressure receiving chambers 13 and 14, and a valve closing spring 16 that urges this diaphragm 15 toward the atmospheric pressure receiving chamber 13.
The valve member 10 is connected to a diaphragm 15 of a negative pressure drive unit 12 via a stem 11, and the valve closing spring 1 is activated by the differential pressure acting on both sides of the diaphragm 15.
6, the diaphragm 1 is driven in the valve opening direction against the diaphragm 1.
If the differential pressure acting on both sides of valve 5 is eliminated, valve closing spring 1
6 to the valve closing position where the fuel suction port 8 is closed.

The throttle valve 3 is configured to be closed in conjunction with the throttle valve, which is fully opened at the time of starting, via an interlocking mechanism 17 shown in FIG. 2, for example.

That is, this interlocking mechanism 17 includes a one-arm lever 19 fixed to the valve shaft 18 of the throttle valve 4 and a double-arm lever 21 fixed to the valve shaft 20 of the throttle valve 3.
, a rod 22 that connects the one-arm lever 19 and the two-arm lever 21, and a valve-opening spring 23 that biases the valve 3 in the opening direction via the two-arm lever 21 and the valve shaft 20. One end of the rod 23 is rotatably connected to the one-arm lever 19, and the other end of the rod 22 is slidably and rotatably connected to an elongated hole 24 formed in the double-arm lever 21. When the one-arm lever 19 is moved to the starting position (indicated by the one-dot chain line) where the throttle valve 4 is fully opened, the two-arm lever 21 is moved to the fully closed position (indicated by the one-dot chain line) via the rod 22 against the valve opening spring 23. (indicated by the dotted chain line), and the valve 3 is moved to
is configured so that it is fully closed.

In the above configuration, when starting the engine,
The throttle valve 4 is fully opened, and the choke valve 3 is fully closed. Then, when the engine starts rotating,
Since the intake passage 7 is closed by the choke valve 3, negative pressure is generated downstream of the throttle valve 4.
As a result of the internal pressure of the intake negative pressure receiving chamber 14 of the negative pressure drive unit 12 becoming a negative pressure, a differential pressure between this negative pressure and the atmosphere acts on the diaphragm 15, and this differential pressure overcomes the valve closing spring 16 to close the stem 11. Then, the valve member 10 is driven in the valve opening direction, and the valve member 10 opens the fuel suction port 8. Further, when the engine in operation is stopped, the negative pressure in the intake passage 7 is eliminated, and the internal pressure in the intake passage 7 becomes equal to atmospheric pressure. As a result, the internal pressure of the intake negative pressure receiving chamber 14 becomes atmospheric pressure, and the diaphragm 15
The differential pressure that was acting on the valve is eliminated, the stem 11 and the valve member 10 are driven in the valve closing direction by the valve closing spring 16, and the valve member 10 closes the fuel suction port 8. Note that when the throttle valve 4 is opened nearly fully open during operation, the pressure difference before and after the throttle valve becomes small, but since the throttle valve 3 is closed in conjunction with the throttle valve 4, the throttle valve 3 The downstream side of the throttle valve 4 is maintained in a negative pressure state, and the shutoff valve 9 is maintained in an open state.

In this way, the intake negative pressure that is immediately resolved when the engine stops is used to open the shutoff valve 9 of the gas fuel supply path 6 while the engine is running, and the shutoff valve 9 of the gas fuel supply path 6 is opened at the same time as the engine is stopped. Since the valve is automatically closed, the gas fuel supply path 6 can be reliably shut off when the engine is stopped, and leakage of fuel gas can be reliably prevented, regardless of the operation of the key switch. especially,
In this embodiment, in which the shutoff valve 9 is configured to open and close the fuel suction port 8 of the mixer 1, the response to start and stop of fuel supply when starting and stopping the engine can be made most sensitive.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view of the main parts of an embodiment of the present invention.
FIG. 2 is a front view of the interlocking mechanism between the throttle valve and the choke valve, and FIG. 3 is a diagram of the fuel gas supply piping of the prior art. 1... Mixer, 4... Throttle valve, 5... Gas supply source (gas cylinder), 6... Gas fuel supply path,
7...Intake path, 8...Fuel suction port, 9...Shutoff valve, 10...Valve member, 11...Stem, 12...
Negative pressure drive unit.

Claims (1)

[Scope of Claim for Utility Model Registration] Closed when there is no intake negative pressure downstream of the throttle valve 4 in the intake passage 7 of the mixer 1 in the gas fuel supply passage 6 from the gas supply source 5 to the fuel suction port 8 of the mixer 1. In a fuel supply system for a gas fuel engine, which is configured with a shutoff valve 9 that is operated, a negative pressure drive section 12 of the shutoff valve 9 is connected to a portion of the mixer 1 on the side opposite to the fuel suction port 8. The stem 11, which is driven forward and backward by the negative pressure drive section 12 of the shutoff valve 9, is inserted into the bench lily section 2 of the mixer 1, and within the bench lily section 2, the valve member 10 provided at the tip of the stem 11 is inserted. A fuel supply device for a gas fuel engine, characterized in that it is configured to face a fuel suction port 8 of a mixer 1 so as to be openable and detachable.