JPH05332200A - Fuel supply device for gas engine - Google Patents

Abstract

PURPOSE:To improve fuel consumption performance, reduce white smoke from a tail pipe, and prevent unconformable combustion which is characteristic to a two-cycle engine by supplying a specified amount of liquefied gas according to an operation condition of a gas engine to a scavenging passage, and reducing an exhaust amount of total hydro carbon (THC). CONSTITUTION:In a fuel supply device, liquefied gas stored in a fuel tank 10 is adjusted in pressure and rate by a regulator 22, and supplied to a gas engine 2, a fuel supply means 26 is arranged for supplying the liquefied gas of a rate according to an operation condition of the gas engine to a scavenging passage 4. The fuel supply means has a main body 28, a piston valve body 32 reciprocating inside a cylinder, a cam 34 which pressurizes the piston valve body 32 and is driven in respect to a crank shaft with a ratio of 1:1, and a spring. A means for varying a sectional area of a port on a fuel inlet side is provided wherein the piston valve body is rotated by means of a lever interlocked to an accelerating pedal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel supply device for a gas engine, and more particularly to a fuel supply device for a gas engine that supplies liquefied gas to the gas engine as fuel.

[0002]

2. Description of the Related Art Gasoline, light oil, etc. are mainly used as fuel for an internal combustion engine mounted on a vehicle or the like. Recently, a gas engine using liquefied gas such as LNG (liquefied natural gas) as fuel. Is proposed. Gas engine
Liquefied gas that is fuel is supplied by the fuel supply device.

As a fuel supply device for a gas engine, there is one disclosed in Japanese Patent Laid-Open No. 2-149756. The fuel supply device for a liquefied gas internal combustion engine disclosed in this publication solves the problem that the supply of the gas-phase gas fuel to the gas engine becomes unstable due to the deposition expansion of the liquid-phase gas fuel in the fuel supply pipe. The inconvenience that hunting occurs in the operating state of the gas engine is solved by stably supplying the gas-phase gas fuel.

The fuel supply device for the gas engine is provided with a fuel pipe from a fuel tank for storing liquefied gas to a fuel supply section such as a fuel injection valve provided in the gas engine. The fuel pipe is opened and closed, for example, in order from the fuel tank side to extract the liquefied gas, a vaporizer for vaporizing the liquefied gas, and a liquefied gas stored in the fuel tank to shut off the gas engine. The stored fuel switching valve and the regulator for adjusting the pressure of the liquefied gas are interposed.

Further, the fuel supply device is provided with a relief pipe extending from the fuel tank to the fuel pipe between the solenoid valve which is the stored fuel switching valve and the regulator. The relief pipe is opened and closed in order from the fuel tank side, a relief valve for pressure adjustment, a storage tank for storing the liquefied gas, and a supply of the liquefied gas stored in the storage tank to the gas engine. The occluded fuel switching valve is interposed.

When the gas engine is driven, the extraction valve and the solenoid valve of the fuel supply device are opened in order to supply the liquefied gas in the fuel tank to the gas engine. As a result, the liquefied gas in the fuel tank flows through the fuel pipe, is vaporized by the vaporizer, is pressure-regulated by the regulator, and is supplied to the gas engine by the fuel supply unit for combustion.

Further, the fuel supply device is generally provided with a relief mechanism, and the relief mechanism has a relief value (for example, 10 kg / cm ² ) or more at which the pressure is set by vaporizing the liquefied gas in the fuel tank. Then, it is opened to supply the vaporized liquefied gas to the storage tank. As a result, the vaporized liquefied gas in the fuel tank is supplied to the storage tank and stored therein.

When the gas engine is stopped, the extraction valve and the stored fuel switching valve are closed and the storage fuel switching valve is closed in order to cut off the supply of the liquefied gas to the fuel tank and the storage tank. This prevents the liquefied gas in the fuel pipe and vaporizer, the relief pipe, and the storage tank from being released to the atmosphere.

[0009]

By the way, in a conventional spark ignition type two-cycle engine, a blow-through of fuel is generally generated, a large amount of total hydrocarbon (THC) is discharged, and fuel efficiency is deteriorated. However, there is an inconvenience that it is economically disadvantageous.

Further, white smoke is emitted from the tail pipe of the two-cycle engine supplied with the liquid fuel, which may cause air pollution and irregular combustion that is peculiar to the two-cycle engine. There is an inconvenience that

[0011]

Therefore, in order to eliminate the above-mentioned inconvenience, the present invention provides a gas engine for supplying a gas engine with a liquefied gas whose pressure is adjusted by a regulator through a fuel tank for storing the liquefied gas. In the fuel supply device, the fuel supply means for supplying the scavenging passage with an amount of liquefied gas according to the operating state of the gas engine is provided.

[0012]

According to the invention as described above, when the gas engine is driven, a predetermined amount of liquefied gas is supplied to the scavenging passage by the fuel supply means according to the operating state of the gas engine, and the total amount of hydrocarbon (THC) discharged To reduce fuel consumption, reduce white smoke from the tail pipe, and prevent irregular combustion peculiar to a two-cycle engine.

[0013]

Embodiments of the present invention will be described in detail below with reference to the drawings.

1 to 5 show a first embodiment of the present invention. In FIG. 1, 2 is a gas engine comprising a spark ignition type two-cycle engine, 4 is a scavenging passage, 6 is a piston, 8 is an exhaust passage, and 10 is a fuel tank for liquefied gas.

The fuel tank 10 is, as shown in FIG.
LNG, CNG, LPG, or other liquefied gas is stored, and is connected to the scavenging passage 4 via a fuel pipe 12.

In the middle of the fuel pipe 12, a manual shut-off valve 14, a pressure reducing valve 16, a filter 18, a solenoid valve 20, and a regulator 22 for adjusting the pressure of the liquefied gas in order from the fuel tank 10 side. The chamber 24 and the fuel supply means 26 are interposed.

The fuel supply means 26 supplies the scavenging passage 4 with the liquefied gas in an amount corresponding to the operating state of the gas engine 2.
It has a configuration for supplying to.

More specifically, the fuel supply means 26 includes a body portion 28, a piston valve body 32 that reciprocates in a cylinder 30 of the body portion 28, a piston valve body 32, and a crankshaft (not shown). The cam 34 driven at a ratio of 1: 1 and the piston valve body 32 are
And a spring 36 biasing to the side.

A fuel supply passage 38 communicating with the fuel pipe 12 is formed in the fuel supply means 26.

The fuel supply passage 38 extends from the outer periphery of the main body 28 to the piston valve body 32 and is a first fuel supply passage 38.
-1, a second fuel supply passage 38-2 extending from the outer periphery of the piston valve body 32 to the central portion and then extending downward to the installation space portion 40 of the spring 36, and the installation space portion 40.
To the injection nozzle 42 from the third fuel supply passage 38-
3 and 3.

The piston valve body 32 is shown in FIG.
As shown in (b), when the lever 44 is connected,
The shape of the inflow port portion 46 of the second fuel supply passage 38-2 is formed to be a long hole having a different cross-sectional area and inclined, and the lever 44 is configured to rotate in conjunction with an accelerator (not shown).

Next, the operation will be described.

The cam 34 is rotated by a crank shaft (not shown), and when the piston valve body 32 is pressed by the cam 34, the first and second fuel supply passages 38-1 and 38-2 are connected to each other,
The pressurized liquefied gas is used as the first to third fuel supply passages 38-.
1, 38-2, 38-3, and is supplied from the injection nozzle 42 to the scavenging passage 4.

It is effective to carry out this injection timing in the vicinity of BDC (bottom dead center) during scavenging shown in FIGS.

Further, the piston valve body 32 is rotated by a lever 44 interlocked with an accelerator (not shown) to change the cross-sectional area of the inflow side opening portion 46 of the second fuel supply passage 38-2, and to change the amount according to the operating state. Liquefied gas is supplied to the scavenging passage 4.

This makes it possible to reduce blowout of liquefied gas, reduce the amount of total hydrocarbon (THC) emitted, improve fuel efficiency, and are economically advantageous.

Further, since the liquefied gas is supplied to the gas engine 2, there is no fear that the liquefied gas will stay in the crank chamber (not shown), and it is possible to prevent the problem that white smoke is emitted from the tail pipe and to pollute the air pollution. In addition, the use of liquefied gas is advantageous for lean combustion, and irregular combustion peculiar to a two-cycle engine can be prevented, which is practically advantageous.

6 and 7 show a second embodiment of the present invention. In the second embodiment, the portions having the same functions as those in the first embodiment will be described with the same reference numerals.

The feature of the second embodiment resides in that the fuel supply means 26 is provided with a diaphragm mechanism 50 for controlling the flow rate of the liquefied gas.

That is, the main body portion 28 and the piston valve body 32
First to third fuel supply passages 38-1, 38-2, 38
-3 is formed, the needle valve element 52 that moves back and forth by the diaphragm mechanism 50 is moved to the third fuel supply passage 38-.
The passage cross-sectional area of the third fuel supply passage 38-3 is changed by projecting and retracting in the middle of 3.

More specifically, the diaphragm mechanism 50
Is a diaphragm 58 that defines the interior into a pressure chamber 54 and a negative pressure chamber 56, and the valve body whose one end is connected to this diaphragm 58 and whose other end appears and disappears in the middle of the third fuel supply passage 38-3. 52 and a spring 60 for urging the valve body 52 in the retracted direction, and the negative pressure chamber 56 has a communication port portion 62 for communicating with an intake system of a gas engine (not shown).
To form.

The cam 64, which comes into contact with the upper surface of the piston valve body 32, is spline-engaged with a shaft portion 66 formed in a twisted shape, and a timing pulley 68 is attached to one end of the shaft portion 66 and a timing pulley 68 is provided. The pulley 68 is provided so as to communicate with a crankshaft (not shown), and the shaft 66
The flange portion 70 is formed at the other end of the.

Then, the spring 72 for urging the shaft portion 66 to the other end side in the axial direction of the shaft portion 66 is attached to the shaft holding portion 74.
And the flange portion 70, and the other end of the shaft portion 66 is pressed by the governor mechanism 76 to change the cam 64 to the retarded or advanced state.

Reference numeral 78 is an O-ring provided between the main body portion 28 and the piston valve body 32 pipe.

By the way, when the gas engine (not shown) is driven, the negative pressure of the intake pipe is the negative pressure chamber 5 of the diaphragm mechanism 50.
6, the valve body 52 is moved forward and backward depending on the strength of the negative pressure of the intake pipe to change the protruding / retracting state to / from the third fuel supply passage 38-3 to control the flow rate of the liquefied gas.

The governor mechanism 76, which operates in response to changes in the engine speed, presses the other end of the shaft portion 66 against the urging force of the spring 72 to retard or advance the cam angle of the cam 64. It is in a state.

That is, the lift amount of the cam 64 increases as the engine speed increases, and the injection timing is slightly advanced.

As a result, the diaphragm mechanism 50 can supply the liquefied gas in an amount corresponding to the negative pressure of the intake pipe to the gas engine, and as in the first embodiment, the blow-through of the liquefied gas can be reduced. In addition, the total hydrocarbon (THC) emission can be reduced, the fuel consumption can be improved, and it is economically advantageous.

Further, as in the first embodiment, the liquefied gas is supplied to the gas engine, so that there is no fear that the liquefied gas will stay in the crank chamber (not shown) and white smoke will be emitted from the tail pipe. The use of liquefied gas is advantageous for lean combustion, and the irregular combustion peculiar to a two-cycle engine can be prevented, which is practically advantageous.

The present invention is not limited to the first and second embodiments described above, and various application modifications are possible.

For example, in the first embodiment of the present invention, the piston valve body of the fuel supply means is rotated by the lever interlocked with the accelerator. However, changes in the engine speed or intake pipe negative pressure, or acceleration, Start, sudden deceleration,
It is also possible to rotate the piston valve element of the fuel supply means according to each operating state such as idle operation.

[0042]

As described in detail above, according to the present invention, in the fuel supply device for the gas engine, which supplies the liquefied gas whose pressure is adjusted by the regulator through the fuel tank storing the liquefied gas to the gas engine, Since the fuel supply means for supplying the liquefied gas in an amount corresponding to the operating state of the gas engine is provided to the scavenging passage, blow-through of the liquefied gas can be reduced, and total hydrocarbon (TH
The emission amount of C) can be reduced, the fuel consumption is improved, and it is economically advantageous. In addition, since the liquefied gas is supplied to the gas engine, there is no fear that the liquefied gas will stay in the crank chamber, and the problem of white smoke from the tail pipe can be prevented, and there is no fear of causing air pollution. With
The use of liquefied gas is advantageous for lean combustion and can prevent irregular combustion peculiar to a two-cycle engine, which is practically advantageous.

[Brief description of drawings]

FIG. 1 is a schematic diagram of a fuel supply device for a gas engine showing a first embodiment of the present invention.

FIG. 2 is an enlarged sectional view of a fuel supply unit.

FIG. 3A is a plan view of a piston valve body and a lever. (B) It is a side view of a piston valve body.

FIG. 4 is a crank chamber compression two-cycle diesel engine (D = 88, S = 100) at 1200 rpm / 1/2 load.
FIG. 3 is a diagram showing pressure fluctuations in the crank chamber and the intake pipe in (3).

FIG. 5: Crank chamber compression 2 at 2250 rpm and full load
It is a figure which shows the pressure fluctuation of the crank chamber and intake pipe of a cycle diesel engine (D = 88, S = 100〓).

FIG. 6 is an enlarged sectional view of a fuel supply means showing a second embodiment of the present invention.

FIG. 7 is a schematic diagram showing a drive configuration of a cam.

[Explanation of symbols]

 2 Gas engine 4 Scavenging passage 6 Piston 10 Fuel tank for liquefied gas 12 Fuel pipe 14 Manual shutoff valve 16 Pressure reducing valve 20 Electromagnetic valve 22 Regulator 26 Fuel supply means 28 Main body 30 Cylinder 32 Piston valve body 34 Cam 36 Spring 38 Fuel supply Passage 38-1 First fuel supply passage 38-2 Second fuel supply passage 38-3 Third fuel supply passage 40 Arrangement space 42 Injection nozzle 44 Lever 46 Inflow port

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[Procedure amendment]

[Submission date] July 16, 1992

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Correction target item name] All drawings

[Correction method] Change

[Correction content]

[Figure 1]

[Fig. 2]

[Figure 3]

[Figure 4]

[Figure 5]

[Figure 6]

[Figure 7]

Claims (1)

[Claims] 1. A fuel supply device for a gas engine, which supplies a liquefied gas whose pressure is adjusted by a regulator to a gas engine through a fuel tank for storing the liquefied gas,
A fuel supply device for a gas engine, comprising fuel supply means for supplying a scavenging passage with an amount of liquefied gas according to an operating state of the gas engine.