JPH08232663A - Combustion chamber for subsidiary chamber type internal combustion engine - Google Patents

Abstract

PURPOSE: To realize improvement in fuel consumption and reforming of emissions such as smoking and HC by providing an air pocket part formed in a hollow in a bottom part side wall surface of a subchamber base to be opened to a subchamber space to serve partly as a subchamber. CONSTITUTION: An air pocket 22, formed of a circular arc-shaped hollow with a position eccentrical from a subchamber center serving as the start point, is provided to be cut in a lower part side wall surface (side wall surface against which atomized fuel collides) of a subchamber base 9 formed with the inside into a reverse truncated cone shape and in a subchamber lower part hollowly provided in a cylinder head 4. The pocket 22 is opened so as to serve partly as a subchamber 2. In the subchamber 2, since gas is burned while introducing new air in the air pocket 22 provided in the subchamber bottom part side wall surface, energy of jet gas to a main chamber 1 from the subchamber 2 is increased, in its turn to activate combustion in the main chamber 1. Thus by improving combustion efficiency and swivelability of an engine, increasing an output and reforming fuel consumption are performed, so that reforming exhaust gas of smoking, HC, etc., can be realized.

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 an internal combustion engine of a subchamber type.

[0002]

2. Description of the Related Art A conventional auxiliary chamber internal combustion engine will be described with reference to FIG. Although the auxiliary chamber injection port has a right cylindrical shape in the figure, it may have a bent cylindrical shape or a tapered shape. The sub-chamber 2 is recessed in the cylinder head, and the sub-chamber 2 is provided at a position away from the cylinder center line AA and offset to the cylinder 8.

The sub-chamber 2 has a hemispherical upper portion and a truncated cone lower portion. A fuel valve 5 for injecting fuel is installed in the sub-chamber 2, and a glow plug 6 for preheating the inside of the chamber 2 at the time of starting the engine. Are installed as needed. The sub-chamber 2 communicates with the main combustion chamber 1 (hereinafter abbreviated as the main chamber) via a sub-chamber injection port 3 provided in a sub-chamber mouthpiece 9 provided in the lower portion of the sub-chamber.
The main chamber is composed of the piston cavity 11, the cylinder 8 and the lower surface of the cylinder head 4.

Next, the operation of the conventional example will be described.
During engine operation, air is sucked into the cylinder during the intake stroke in which the piston 7 descends, and the intake air in the main chamber 1 is compressed by the piston 7 during the compression stroke in which the piston 7 rises. And flows into the inside to generate a vortex S. The velocity of the vortex S becomes maximum at the top dead center of the piston 7. Next, when fuel is injected from the fuel valve 5 along the direction of the vortex S near the top dead center, the fuel swirls in the sub chamber together with the vortex S to mix with the air to form a mixture, and near the glow plug. Ignite and start burning.

When combustion is started in the sub-chamber 2, the pressure in the sub-chamber rises, and the combustion gas and the unburned gas are pistoned due to the pressure difference between the main chamber 1 and the sub-chamber 2 (main chamber <sub-chamber). At the time of descending 7, the water is ejected into the main chamber 1 through the auxiliary chamber injection port 3. The jetted gas gives work to the piston 7 and, at the same time, mixes with the air in the main chamber 1 and further diffuses and burns.

[0006]

In order to improve the output of the sub-chamber type internal combustion engine, the fuel consumption, and the exhaust gas smoke and HC, the combustion in the sub-chamber 2 is first activated to the main chamber 1. It is necessary to increase the ejection energy of. Conventionally, the sub-chamber injection port 3 is throttled to increase the vortex velocity to promote the formation of the air-fuel mixture, thereby promoting the combustion in the sub-chamber 2. Since the heat loss increases, it is necessary to promote the combustion in the sub chamber 2 with the expansion of the sub chamber injection port 3.

That is, if the lower part of the sub-chamber 2 has an inverted frustoconical shape as in the conventional case, ignition combustion starts from the vicinity of the glow plug 6 in the sub-chamber 2, so that a new jet gas (unburned gas, burned gas) is generated. Since it is somewhat difficult to introduce air, it is difficult to promote combustion in the sub chamber. Therefore, the combustion energy in the sub-chamber 2 is weak, and thus the jetting energy into the main chamber 1 is also low, and the combustion in the main chamber 1 is not easily activated, so that the output is reduced, and the smoke, HC (unburned hydrocarbons) ) Is likely to increase.

The object of the present invention is to rapidly increase the gas pressure in the sub-chamber, to quickly generate a jet flow from the sub-chamber nozzle to the main chamber, activate combustion in the main chamber, and accelerate completion of combustion. It is an object of the present invention to provide a combustion chamber of an internal combustion engine of a sub-chamber type in which complete combustion is performed and fuel consumption can be improved and exhaust gas such as smoke and HC can be improved.

[0009]

A combustion chamber of a sub-chamber internal combustion engine according to the present invention is provided with a center line BB of the sub-chamber provided at a position eccentric to the center line A-A of the cylinder. A recess is formed on the bottom side wall surface of the sub-chamber mouthpiece 9 near the A-A, starting from a position eccentric from the center line A-A of the sub-chamber, and opening into the sub-chamber space to form a part of the sub-chamber. It is characterized in that an air pocket portion 22 forming

[0010]

When the piston rises during the compression stroke of the engine, the intake air in the main chamber is compressed and flows into the sub chamber through the sub chamber injection port to generate a vortex in the sub chamber. Then, when the fuel is injected from the fuel injection valve along the direction of the vortex S, the fuel is mixed with the vortex air and is made to flow downstream,
Ignition and combustion starts near the glow plug, and the jet gas, which is a mixture of unburned and burnt gases, reaches the lower side wall and the bottom while burning.

At this time, in the sub-chamber, gas is burned while introducing fresh air in the air pocket 22 provided at the bottom of the sub-chamber mouthpiece 9, so that the ejection energy from the sub-chamber to the main chamber increases. As a result, combustion in the main chamber is activated. It is necessary to select the specifications of the volume of the air pocket portion so that the volume ratio of the sub chamber is optimized depending on the engine so as not to reduce the compression ratio.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a sectional view around the combustion chamber, and FIG. 2 is an enlarged top view of a lower portion of the sub chamber. 1 and 2 are different from the conventional example only in that an air pocket 22 is newly provided.

In FIG. 1, the sub-chamber base 9 is formed in the lower part of the sub-chamber recessed in the cylinder head 4 and the inside of which is formed into an inverted truncated cone shape.
On the lower side wall surface (side wall surface where fuel spray collides) of the sub chamber 2 is formed an air pocket 22 formed of an arcuate recess having a position eccentric from the center of the sub chamber as a starting point.
It is opened to become a part of. The air pocket has a circular arc shape and a cylindrical shape, but in addition to this, an unillustrated square shape such as a prismatic shape or a spherical shape can be considered.

Next, the operation of the above embodiment will be described.
During the compression stroke of the engine, when the air in the main chamber 1 is compressed by the rise of the piston 7, the air flows into the sub chamber 2 through the sub chamber injection port 3 and a swirl S is generated. Next, when the fuel is injected from the fuel injection valve 5 along the swirl, the fuel is swirled by the swirl S.
Ignition and combustion is started from the vicinity of the glow plug 6 provided on the downstream side while being mixed with. The jet composed of a mixture of unburned and burnt gases reaches the lower side wall surface and the bottom surface while burning.

At this time, in the sub-chamber 2, the gas burns while introducing the fresh air in the air pocket 22 provided on the side wall surface of the sub-chamber lower part, so that the gas ejected from the sub-chamber 2 to the main chamber 1 Energy is increased, and combustion in the main chamber 1 is activated. When the air pocket 22 is provided, it is necessary to select its specifications so as to obtain the optimum sub chamber volume ratio without lowering the compression ratio.

[0016]

With the sub chamber shape of the present invention, the jet gas that has started ignition and combustion in the vicinity of the glow plug is ejected from the sub chamber 2 into the main chamber 1 through the sub chamber nozzle 3. , The air pocket 2 provided on the lower side wall of the sub chamber
Combustion is carried out while introducing fresh air in 2.

Therefore, since the combustion is promoted and accelerated in the latter part of the combustion in the latter part of the combustion, the jet flow energy from the auxiliary chamber injection port 3 is increased and the combustion in the main chamber 1 is promoted. Therefore, the combustion efficiency and the equal volume of the engine are improved, the output is increased and the fuel efficiency is improved, and the exhaust gas such as smoke emission and HC can be improved.

[Brief description of drawings]

FIG. 1 is a sectional view around a combustion chamber according to an embodiment of the present invention.

FIG. 2 is an enlarged top view of a lower part of a sub chamber of the combustion chamber of the above.

FIG. 3 is a prior art example corresponding to FIG. 1.

[Explanation of symbols]

1 ... Main chamber, 2 ... Sub chamber, 3 ... Sub chamber nozzle, 4 ... Cylinder head, 5 ... Fuel injection valve, 6 ... Glow plug, 7 ... Piston, 8 ... Cylinder, 9 ... Sub chamber base, 10 ... Piston top Surface, 55 ... Fuel spray, 22 ... Air pocket part (recess),
A-A ... Cylinder center line, B-B ... Sub chamber center line, S ... Vortex flow.

Claims (1)

[Claims] 1. A sub-combustion chamber of a sub-chamber internal combustion engine (hereinafter abbreviated as a sub-chamber), which is provided at a position eccentric to the cylinder center line A-A from the sub-chamber center line BB to the cylinder center line. A recess is formed on the bottom side wall surface of the sub-chamber mouthpiece (9) near the A-A, with a position eccentric from the center line A-A of the sub-chamber as a starting point, and opens into the sub-chamber space to open the sub-chamber. A combustion chamber of a subchamber internal combustion engine provided with an air pocket portion (22) forming a part.