JPH07166873A - Fuel direct injection gas fuel internal combustion engine and its combustion method - Google Patents

Abstract

PURPOSE:To improve performance by developing a fuel mixture block with a combustion chamber center region serving as the start point, constructing a physical condition by ignition capable from the center region, shortening a combustion period by uniformity of a flame propagation distance, also suppressing self ignition in an end region, attaining applying high compression ratio, and attaining simultaneously improving thermal efficiency and low public pollution of exhaust. CONSTITUTION:A fuel jet flow collision part 4 is arranged in the center region of a combustion chamber 3, a fuel supply valve 5 is protruded from a cylinder head 1 to the vicinity of the collision part 4, an injection fuel group is partly diffused by colliding action to form a stratified mixture block of high fuel density thinning it in accordance with going to an external region in the combustion chamber center region, further for performing ignition to this mixture and flame propagation from the combustion chamber center region, an electrode 11 is constituted partly in the fuel supply valve, and sure ignition is performed by a discharge between electrode 11 and an electrode 12 constituted in the colliding part. The fuel supply valve uses a check valve of small sized poppet valve or the like, and a fuel supply period, from an intake stroke to a compression stroke former period, is by electrically or mechanically opening/closing a nozzle.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas fuel internal combustion engine and its combustion system.

[0002]

It is well known that when a gas fuel is used for an internal combustion engine, it is effective to supply it to the engine as a liquid having a small volume. However, in addition to cost increase for fuel liquefaction and high compression, storage and storage are required. There are many problems with storage and it is not in practical use at present.

Further, the high compression ratio direct injection system, which is advantageous in terms of thermal efficiency as an engine, has high power loss as well as a complicated device, resulting in little overall merit in engine performance. Has arrived. Therefore,
The pre-mixing system is the main type for small gas engines currently in use, and the type with a sub-combustion chamber is the mainstream for medium size engines.

For this reason, the premixing type small engine has a low thermal efficiency due to the limitation of the compression ratio due to the knocking phenomenon. The diffusion rate of gas engines is currently low.

[0005]

SUMMARY OF THE INVENTION The present invention is intended to improve the thermal efficiency of a gas engine, reduce the pollution of exhaust gas, reduce the engine manufacturing cost, and facilitate maintenance. The supply condition and the ignition condition are developed by the new technical means for the fuel supply technology and the ignition condition, and the new technology eliminates the knocking phenomenon which is a high compression ratio barrier necessary for improving the thermal efficiency of the engine. The purpose of the present invention is to present an effective technology for high performance and low pollution of a gas engine by both effects of ignition from the central region and reduction of combustion period due to flame propagation.

[0006]

In the gas engine, the present invention first describes the formation of a mixture of gas fuel and air, which is a predominant element and a precondition for the combustion reaction of the gas engine, and its development in the central region of the combustion chamber. It is in the technological development of how to form it.

That is, in the present invention, a means for forming an arbitrary air-fuel mixture in the central region of the combustion chamber, and a jet flow control collision portion for diffusing the fuel jet in the central region of the combustion chamber are provided. The fuel supply control device is configured so that the jet flow is controlled and a portion of the jet flow is surely collided with the outer cylinder of the injection valve in a positional relationship close to the colliding part. An electrode for spark discharge is formed on a part of the tip of the injection valve outer cylinder and a part of the collision part.

Therefore, the fuel group supplied from the injection valve in a jet shape into the combustion chamber can be freely diffused and expanded in any direction from the collision point as a starting point by the correlative design of the shape of the jet flow and the shape of the collision section. There is.

In this case, in the development of the air-fuel mixture, a stratified air-fuel mixture region in which the fuel density is higher in the central region (collision point) and the fuel density is lower in the outer region is formed by the correlation with the cavity shape. .

As described above, since the air is mainly present in the end area of the combustion chamber due to the formation of the layered mixture lump having the high fuel density in the central area of the combustion chamber and the thinner the outer area, the end gas is obtained even if the high compression ratio is adopted. The knocking problem will never occur.

In addition, ignition from the central region is effective in equalizing and shortening the flame propagation arrival distance, and the combustion period is shortened.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, a fuel gas injection nozzle portion (2) is provided in a central region of a cylinder head portion (1) so as to project into a piston combustion chamber (3), and a fuel collision diffusion control portion (4) is provided at a position opposed to the nozzle tip. Is provided.

The collision diffusing portion (4) is provided so as to be located at the center axis of the cylinder and substantially at the center of the cavity space section (combustion chamber) formed in the piston at the piston top dead center position.

The correlation between the fuel injection nozzle and the fuel collision diffusion section is as shown in FIG. 1. In this example, a mushroom valve type opening / closing nozzle (5) is used, and the collision section opposite to this has a fuel injection control hole at the center. It is a simple component structure having (6) and is supported by the head portion by a plurality of support columns (7).

The fuel supply timing is started by the air intake stroke of the piston and is performed by opening and closing the mushroom valve nozzle so as to end in the first half of the compression stroke, and the valve is electrically or mechanically opened and closed at the base (8). The action takes place.

It is not necessary to use high pressure as the supply pressure of the fuel gas, and the fuel gas is supplied through the pressure adjusting section (9).

As shown in FIG. 2, a group of fuels supplied at such a timing is partially expanded through the hole (6) of the collision part (4) into the cavity as shown in (A). The part is developed in the vicinity of the collision part as in (B) by the collision action.

Then, while being compressed and reaching the top dead center, mixing and activation in the cavity are promoted by the atmospheric pressure and temperature, and ignition is effected by spark discharge in this atmosphere.

In this case, the fuel does not exist in the squish region and only air is present, and by suppressing the intake air swirl flow in the vicinity of the wall surface in the cavity, the fuel group does not form a rich region on the wall surface.

That is, at the compression top dead center, the expansion of a stratified mixture having a high fuel density in the central region of the combustion chamber and a lower fuel density in the outer region is rationally achieved. As a result, the end gas knocking phenomenon does not occur.

For ignition, sparks are generated in a part where the energizing circuit (10) is formed in a part of the outer region of the injection nozzle, the tip of the circuit is used as an electrode (11), and a gap in which an electrode (12) is provided in a part of the collision part. It is performed by discharge.

In this case, if the outside of the nozzle is made of a heat-resistant / oxidation-proof / insulating material such as ceramics, it is easy to construct the energizing circuit (11) in a part of it, and it is not necessary to use a separate electrode, and the cost is reduced. Is advantageous.

[0023]

The structure of the present invention in a gas fuel engine is characterized in that, in a wide operating range in which the fuel supply amount is varied according to the load, a fuel air region is formed near the ignition electrode that is always ignitable with a small amount of discharge energy. In addition, by setting the starting point of the flame kernel associated with ignition as the central region of the combustion chamber, the flame propagation from the flame kernel to the peripheral region is rationalized rationally, and as a result, the combustion period shortening action is realized. .

Further, the stratified mixture distribution characteristic in which the fuel density is high in the central area of the combustion chamber and the fuel density decreases in the outer area confirms that the end gas knocking phenomenon does not occur, and is highly advantageous for improving thermal efficiency. A compression ratio can be adopted.

Further, according to the fuel supply means and the air-fuel mixture forming / developing action of the present invention starting from the central region of the combustion chamber, the air swirl flow at the time of intake is not necessary, the intake passage can be easily designed, and intake charge can be achieved. Efficiency is improved.

[0026]

EFFECTS OF THE INVENTION Since swirl flow due to intake air is not required, the intake passage resistance is reduced, the charging efficiency is improved, and the intake charging efficiency is improved, so that the specific output of the engine is improved.

Since the cause of the end gas knocking is eliminated by the stratified mixture distribution, a high compression ratio can be adopted and the thermal efficiency of the engine is improved. Therefore CO ₂
It is effective in suppressing

Reliable ignition from the central region of the combustion chamber equalizes the flame propagation distance and shortens the combustion period.

By suppressing the fuel distribution in the vicinity of the wall surface by the stratified mixture distribution, the unburned fuel content is reduced, and it is possible to achieve the purpose of reducing exhaust pollution.

The present invention has a simple structure in addition to the above characteristics.
It will be easy and will play an important role in the diversification of fuel, energy consumption and emission pollution of the earth in the future, and will greatly contribute to global environment protection and resource saving.

[0031]

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a configuration of the present invention.

FIG. 2 is an explanatory view of a fuel gas diffusion action according to the present invention.

[0032]

[Explanation of symbols]

 1 ... Cylinder head part 2 ... Fuel gas injection nozzle 3 ... Piston combustion chamber 4 ... Fuel collision diffusion control part 5 ... Pixel valve nozzle 6 ... Fuel jet control hole 7 ... Support pillar 8 ... Nozzle opening and closing operation part 9 ... Fuel gas adjustment Pressure part 10 ... Energizing circuit 11 ... Discharge electrode 12 ... Discharge electrode A = main development area of fuel gas B = collision diffusion area of fuel gas

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Claims (2)

[Claims] 1. A fuel gas injection valve having an electrode structure in the vicinity of the central region of the combustion chamber as means for forming a stratified mixture lump having a high fuel density in the central region of the combustion chamber and a lower fuel density in the end region. A gas fuel internal combustion engine characterized by having a gas fuel collision diffusion control section for projecting this tip into the central region of the combustion chamber and controlling and diffusing the supplied fuel flow by rectification and collision. 2. A combustion system for a gas fuel engine, characterized by performing both a diffuse fuel supply system starting from the center of the combustion chamber and a system of spark ignition from the center of the combustion chamber.