JP2552578Y2 - Combustion chamber of subchamber internal combustion engine - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a combustion chamber of a sub-chamber internal combustion engine.

[0002]

2. Description of the Related Art A combustion chamber of a conventional sub-chamber internal combustion engine is shown in FIGS.
4 will be described. FIG. 3 is a sectional view when a piston of a combustion chamber of a conventional sub-chamber internal combustion engine is at a top dead center, and FIG. 4 is a sectional view taken along line IV-IV in FIG. In the figure, reference numeral 7 denotes a cylinder, 4 denotes a cylinder head, and 6 denotes a piston, all of which are known elements of an internal combustion engine. Reference numeral 2 denotes a sub-combustion chamber provided in the cylinder head 4 and having a substantially cylindrical shape. The auxiliary combustion chamber has various shapes based on a cylindrical shape, a spherical shape, and a conical shape, but this example is based on a cylindrical shape. 1 is a main combustion chamber and a piston 6
, The lower surface of the cylinder head 4, and the space surrounded by the cylinder 7. Reference numeral 8 denotes a sub-chamber base, which forms the tip of the sub-combustion chamber 2 and protrudes into the main combustion chamber 1.
Is divided. Reference numeral 3 denotes a sub-chamber nozzle, which has eight holes formed at the tip of the sub-chamber base 8 and is provided at equal intervals radially with respect to the center line of the sub-chamber base 8. Reference numeral 5 denotes a fuel injection valve which is open to the sub combustion chamber.

Next, the operation of the conventional example will be described. During the compression stroke during engine operation, compressed air in the cylinder flows from the main combustion chamber 1 through the sub chamber injection port 3 into the sub combustion chamber 2. The fuel is injected from the fuel injection valve 5 into the sub-combustion chamber 2 slightly before the top dead center of the piston. The injected fuel is mixed with high-temperature air having a temperature equal to or higher than the ignition point, and a part of the fuel is self-ignited and the pressure in the sub-combustion chamber 2 is increased. The fuel is ejected from the injection port 3 into the main combustion chamber 1 and mixed with air in the main combustion chamber to burn. During this time, the piston passes the top dead center and enters the expansion stroke.

[0004]

The combustion chamber of the conventional sub-chamber internal combustion engine has the following disadvantages. In order to improve the fuel efficiency and smoke emission of the sub-chamber internal combustion engine, it is important to form a mixture of fuel and air in the main combustion chamber, and therefore to promote combustion. In the prior art, a plurality of sub-chamber nozzles are provided at equal intervals, so if the total area of the sub-chamber nozzles is constant and the number of sub-chamber nozzles is reduced, the diameter of each sub-chamber nozzle increases, so that the jet penetration improves. The jet dispersibility deteriorates, the air utilization rate between the jets deteriorates, and the combustion becomes poor. Conversely, increasing the number of sub-chamber injection ports increases the dispersibility of the jet flowing from the sub-combustion chamber to the main combustion chamber, but reduces the diameter of each injection port, lowering the jet penetration, resulting in the formation of a fuel-air mixture and combustion. Getting worse. SUMMARY OF THE INVENTION An object of the present invention is to provide a combustion chamber for promoting the formation of a mixture of fuel and air in the main combustion chamber and thus the combustion in order to solve the above problems and reduce fuel consumption and smoke emission.

[0005]

SUMMARY OF THE INVENTION The gist of the present invention is that a main combustion chamber and a sub-combustion chamber provided inside a sub-chamber base whose tip projects from the cylinder head into the main combustion chamber are provided. In the combustion chamber of the internal combustion engine which is communicated with the sub-chamber injection port, the plurality of sub-chamber injection ports have two adjacent center lines (C-C) arranged near the center of the main combustion chamber. The main combustion chamber extends from the sub-combustion chamber toward the outer periphery, and the extension of the center line (C-C) intersects at a position near the outer periphery of the main combustion chamber in horizontal projection. A combustion chamber of a sub-chamber internal combustion engine.

[0006]

A part of the fuel injected into the sub-combustion chamber burns and the pressure in the sub-combustion chamber rises, and from the sub-combustion chamber to the outer periphery of the main combustion chamber from the sub-combustion chamber provided near the center of the main combustion chamber When burned unburned gas or fuel flows out to the main combustion chamber through the sub chamber injection port extending toward the main chamber, the extension of the axis of two adjacent sub chamber injection ports intersects at a position near the outer periphery in the main combustion chamber Therefore, the jets collide with each other at the intersection, the vectors are synthesized, and the jet penetration can be improved. Further, since the impinging jet causes large turbulence in the jet (composed of burned gas, fuel, and air), the formation and combustion of a mixture of unburned fuel and air in the main combustion chamber can be promoted.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a cross-sectional view of the combustion chamber when the piston according to the embodiment is at the top dead center, and FIG. 2 is a cross-sectional view along II-II in FIG. In the figure, reference numeral 1 denotes a main combustion chamber, which is a space surrounded by the top surface of the piston 6, the cylinder head 4, and the cylinder head 7. Reference numeral 2 denotes a sub-combustion chamber which is provided in a sub-chamber base 8 fixed to the cylinder head 4 and has a substantially cylindrical shape. Secondary combustion chamber 2
There are various shapes based on a cylindrical shape, a spherical shape, and a disk shape, but this embodiment is based on a cylindrical shape. Reference numeral 6 denotes a fuel injection valve which is open to the sub-combustion chamber 2. A glow plug for preheating the sub-combustion chamber when the engine is started is installed in the sub-combustion chamber 2 as necessary, but is not shown.

The sub-chamber base 8 has the tip of the sub-combustion chamber 2 formed therein and protrudes into the main combustion chamber. The sub-combustion chamber 2 is arranged substantially at the center of the main combustion chamber 1 as shown in FIG. Reference numeral 3 denotes a sub-chamber nozzle, which is provided at a portion of the sub-chamber mouthpiece 8 projecting into the main combustion chamber 1.
And an even number of holes communicating the main combustion chamber 1 with each other. As shown in FIG. 2, the extension of two adjacent center lines (C-C) at the outer peripheral portion in the main combustion chamber 1 in horizontal projection. Crossed.

Next, the operation of the embodiment will be described. In the compression stroke during engine operation, air in the cylinder is compressed and flows into the sub-combustion chamber 2 through the sub-chamber injection port 3. Near the end of the compression stroke, fuel is injected from the fuel injection valve 5 into the sub-combustion chamber 2, a part of the injected fuel burns in the sub-combustion chamber 2, and the pressure in the sub-combustion chamber 2 increases. The unburned matter in the sub-combustion chamber is ejected from the sub chamber injection port 3 to the main combustion chamber 1 together with the burned matter. During this time, the piston 6 passes the top dead center and enters an expansion stroke. The main combustion chamber 1
The unburned matter ejected to the air mixes with the air in the main combustion chamber 1 and burns.

A jet jet from any one sub chamber injection port 3 into the main combustion chamber 1 collides with any adjacent similar jet in the main combustion chamber 1. FIG. 2 schematically shows the state. By the collision of the jets, the vectors of the respective jets are synthesized, and the jet penetration can be improved. Furthermore, since the impinging jet causes large turbulence in the jet (composed of burned gas, fuel, and air), a mixture of unburned fuel and air in the main combustion chamber 1 is formed.
It promotes combustion and improves fuel efficiency and smoke emission.

[0011]

[Effect of the Invention] The present invention is configured as described above, so that the collision of two jets at the outer peripheral portion in the main combustion chamber improves the penetration of the jet, and also causes a large turbulence in the jet. Formation of air-fuel mixture and combustion in the combustion chamber are promoted, and fuel consumption and smoke emission can be reduced.

[Brief description of the drawings]

FIG. 1 is a sectional view of a combustion chamber according to an embodiment of the present invention when a piston is at a top dead center.

FIG. 2 is a sectional view taken along the line II-II in FIG.

FIG. 3 is a cross-sectional view when a piston of a conventional combustion chamber is at a top dead center.

FIG. 4 is a sectional view taken along line IV-IV in FIG. 3;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Main combustion chamber, 2 ... Subcombustion chamber, 3 ... Subchamber nozzle, 4 ... Cylinder head, 8 ... Subchamber base, cc ... Center line of subchamber injection port.

Claims (1)

(57) [Scope of request for utility model registration] An internal combustion engine in which a sub combustion chamber provided inside a sub chamber base whose tip projects from a cylinder head into a main combustion chamber and the main combustion chamber are communicated by a plurality of sub chamber injection holes. In the combustion chamber, the plurality of sub-chamber injection ports are:
Two adjacent center lines (CC) extend from the sub-combustion chamber disposed near the center of the main combustion chamber toward the outer peripheral side of the main combustion chamber, and the center line (CC) is provided. A combustion chamber of a sub-chamber internal combustion engine, characterized in that, in a horizontal projection, an extension line of the crosses at a portion near the outer periphery of the main combustion chamber.