JP3000246B2 - Gas engine combustion chamber - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a combustion chamber of a gas engine using mainly natural gas as a fuel.

[0002]

2. Description of the Related Art Gasoline and light oil are usually used as fuel for an internal combustion engine, and it is known to increase the compression ratio in order to increase the theoretical thermal efficiency during combustion. A diesel engine that performs compression ignition using light oil as fuel is operated at a compression ratio of about 16 to 23.

[0003] Further, in the case of an engine using gas as a fuel, when compressed fuel is injected into air, it is difficult to mix the fuel uniformly. Therefore, it is important to devise a method for quickly generating a uniform mixture. For this reason, it is common to prepare a mixture in advance, fill the cylinder with the mixture, and ignite with an ignition plug. In this method, the compression ratio is about 10 to 13, and the theoretical thermal efficiency is too small. It is not high, and the theoretical thermal efficiency is calculated to be about 50%, and if the compression ratio is increased to about 20, a theoretical thermal efficiency of 62% will be obtained.

[0004]

As described above, increasing the compression ratio improves the theoretical thermal efficiency. However, as the equivalence ratio of the fuel increases, the specific heat ratio K decreases and the theoretical thermal efficiency deteriorates. In a gas engine, it is an important issue to quickly mix gas and air to generate a uniform mixture in a sub-combustion chamber and to quickly improve combustion in a main chamber.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide a combustion chamber of a gas engine which aims to achieve a high compression ratio of a gas engine and a rapid generation of an air-fuel mixture. It is in.

[0006]

According to the present invention, in order to attain the above object, gaseous fuel supplied at a low pressure is supplied to a sub-combustion chamber to be premixed with air, thereby achieving high mixing. In a combustion chamber of a gas engine that burns at a compression ratio, a depressed main combustion chamber provided on an upper surface of a piston, a sub-combustion chamber having a communication port opened corresponding to the main combustion chamber, and a sub-combustion chamber An umbrella valve formed in an inverted umbrella shape that moves to the side to open a communication port, and sends compressed air from the main combustion chamber side toward the side wall of the sub-combustion chamber and ignites the mixture in the sub-chamber combustion chamber And a control valve for injecting the fuel into the main combustion chamber in a direction perpendicular to the main combustion chamber.

[0007]

A control valve formed in an inverted umbrella shape is provided at the communication port between the sub-combustion chamber and the main combustion chamber, and a rectifying plate is provided below the control valve. The fuel mixture is sent in the direction to speed up the generation of the mixture with the fuel gas, and the rich mixture ignited from the sub-combustion chamber becomes a cylindrical flame perpendicular to the main combustion chamber by the rectifier. Since it is ejected, it mixes smoothly with the air on the upper surface of the piston to obtain an extremely good combustion state.

[0008]

Next, an embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a structural view of a main part showing an embodiment of a combustion chamber of a gas engine according to the present invention. In FIG. 1, 1 is a cylinder, 2 is a piston, and the center of the upper surface of the piston 2 is shown. A hollow main combustion chamber (main chamber) 21 is engraved in the hole, and the diameter of the hollow is smaller than that of the opening.

Reference numeral 3 denotes a sub-combustion chamber (sub-chamber), which is made of, for example, high-strength and heat-resistant ceramic.
1 is provided at a central portion, and its vertical cross-section is formed in a substantially heart shape, and the bottom is opened above the main chamber 21 as a communication port 31 with the main chamber.

Reference numeral 4 denotes a control valve for controlling the opening and closing of the communication port 31. The control valve is provided with an umbrella valve 41 which closes the valve seat 32 of the communication port 31 from above and closes the sub-chamber 3, and below the umbrella valve 41. Rectifying plate 42 having a predetermined smaller diameter than the hole diameter of communication port 31
Are provided to control the direction in which the flame is blown from the sub-chamber 3 during fuel combustion. The stem 43 of the control valve 4 is axially supported by the valve guide 33 on the upper wall of the sub-chamber 3, and the stem 43 is biased by a spring 45 that pushes up the upper plate 44.

Reference numeral 5 denotes a gas fuel valve mounted on the upper side of the sub-chamber 3 for controlling the gas flow by opening and closing the fuel gas supply port 34 from the gas supply pipe 53 to the sub-chamber 3. And a valve spring 52 for pushing up the upper end of the stem 51.
Thus, the supply port 34 is normally closed.

Next, the operation of this embodiment constructed as described above will be described. In the compression stroke of the engine, as the piston 2 rises, compressed air pushes up the control valve 4 to cause the sub-chamber 3 to pass through the communication port 31. Since the umbrella valve 41 of the control valve 4 expands upward, the main flow of the compressed air proceeds toward the side wall having a large volume in the sub chamber and is supplied through the gas fuel valve 5 as shown in FIG. The fuel gas is efficiently mixed with the fuel gas to be produced at once, and a mixture is three-dimensionally generated.

Immediately after the mixing, the combustion is started, and the pressure of the combustion gas rises. Therefore, the combustion gas containing the rich mixture becomes a flame, and as shown in FIG.
It blows out from between 1 and the communication port 31 in the direction of the main room 21.

In this case, a rectifying plate 42 is provided at the lower end of the control valve 4.
Is formed, the flame becomes cylindrical and blows downward from the gap with the communication port 31 as shown in the figure, and the air on the piston upper surface becomes a squish flow at right angles to the flow of the flame. Since it is supplied in the direction, the rate of change in volume is increased, combustion is efficiently performed in the main chamber 21, and the piston 2 is lowered strongly. Then, the flame containing a large amount of air blown out from the hollow of the main chamber as the combustion progresses collides with the flame from the sub-chamber at right angles to further promote the mixing.

Although the present invention has been described with reference to the above-described embodiment, various modifications are possible within the scope of the present invention, and these modifications are not excluded from the scope of the present invention.

[0017]

According to the present invention, a control valve having an inverted umbrella-shaped umbrella valve is attached to the communication port between the sub-chamber to which fuel gas is supplied and the main chamber above the piston, and rectification is performed on the lower surface thereof. With the addition of a panel, the compressed air when the piston rises is sent by the umbrella valve toward the side wall of the sub-chamber with a large volume to promote the generation of air-fuel mixture with the fuel gas. Air is blown out as a cylindrical flame in the direction of the main chamber by the rectifier below the control valve, so that the air on the top surface of the piston flows at a right angle from the lateral direction, and the mixture of the flame and air becomes good, There is an effect that combustion is actively performed .

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a main part showing one embodiment of a combustion chamber of a gas engine according to the present invention.

FIG. 2 is an explanatory diagram showing the flow of compressed air into a sub-chamber at the end of a compression stroke according to one embodiment of the present invention .

FIG. 3 is an explanatory diagram showing a state in which an ignited air-fuel mixture in a sub-chamber flows into a main chamber at an early stage of an explosion stroke according to one embodiment of the present invention .

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Cylinder 2 ... Piston 3 ... Subcombustion chamber 4 ... Control valve 5 ... Gas fuel valve 21 ... Main combustion chamber 41 ... Umbrella valve 42 ... Rectifier board

Continuation of the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) F02B 19/02 F02B 19/08 F02B 19/14 F02B 19/16 F02B 19/18 F02M 21/02 301

Claims (2)

(57) [Claims] A gas fuel supplied at a low pressure is supplied to a sub-combustion chamber to be premixed with air and to be burned at a high compression ratio. A hollow main combustion chamber, a sub-combustion chamber having a communication port that opens corresponding to the main combustion chamber, and an umbrella formed in an inverted umbrella shape that moves toward the sub-combustion chamber and opens the communication port. And a control valve for supplying compressed air from the main combustion chamber side toward the side wall of the sub-combustion chamber and causing the ignited air-fuel mixture in the sub-combustion chamber to be emitted perpendicularly to the main combustion chamber. Combustion engine of a gas engine. 2. A combustion chamber for a gas engine according to claim 1, wherein said control valve is provided with a rectifier having a diameter smaller than an inner diameter of said communication port below said umbrella valve.