JPS5924818Y2 - Combustion device for split combustion internal combustion engine - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a combustion device for a split combustion internal combustion engine in which combustion is performed in multiple stages using a reciprocating piston.

A split combustion internal combustion engine is a prior art example, as shown in Japanese Patent Application Laid-Open No. 51-14511, in which a combustion chamber formed in a cylinder head is separated from the top by a piston having an auxiliary piston protruding from the top. The combustion chamber is divided into a plurality of chambers during a predetermined period before and after the point, and ignition occurs in the first combustion chamber, and immediately before or immediately after the first combustion chamber communicates with the second combustion chamber due to the descent of the piston during the expansion stroke. , a split combustion internal combustion engine in which the air-fuel mixture in the second combustion chamber is ignited by the flame from the first combustion chamber, and the combustion weight ratio in each chamber and the division period of the combustion chamber are adjusted as appropriate. By making the combustion mode closer to constant-pressure combustion, the maximum pressure and temperature of the initial combustion are suppressed, and the generation of nitrogen oxides (NOx), which is a harmful component of exhaust gas, is suppressed, and in the later stages of combustion, the combustion is carried out by torch ignition. By increasing the speed, fuel efficiency and output can be maintained.

In such split-combustion internal combustion engines, by making the air-fuel mixture lean, it is possible to reduce the generation of carbon monoxide (CO) and hydrocarbons (HC), which are harmful exhaust components. Fuel consumption can also be reduced, but on the other hand, there is a problem in that a lean mixture reduces ignitability and combustion speed.

Utility Model Application Publication No. 1987, which is an example of prior art that solves such problems.
Publication No. 12805 discloses a secondary piston in which several ribs are formed in the radial direction extending from the dividing boundary surface of the first and second combustion chambers toward the top of the piston at top dead center. According to the above, during the compression stroke, several knobs guide the flow of the air-fuel mixture from the gap between the auxiliary piston and the first combustion chamber to the second combustion chamber, resulting in large turbulence. Furthermore, thick turbirence is generated in the air-fuel mixture in the first combustion chamber, resulting in poor ignitability of the air-fuel mixture.
The ribs also guide the flame into the combustion chamber, causing large turbulence, which has the disadvantage of reducing the combustion speed of the air-fuel mixture in the second combustion chamber, and thus reducing the output.

The present invention eliminates these drawbacks, reliably ignites even lean mixtures, has a high combustion speed, and reduces harmful exhaust components such as NOx, CO, and HC without reducing fuel efficiency or output. The purpose is to obtain an internal combustion engine.

In order to achieve this objective distantly, the present invention provides a compression ratio difference between each divided combustion chamber in the above-mentioned split combustion internal combustion engine, and a comb-like turbulence generating member near the boundary of each chamber. By providing this, fine turbulence is created in the air-fuel mixture flowing into the first combustion chamber during the compression stroke, improving ignitability, and fine turbulence is created in the flame jetting out from the first combustion chamber into the second combustion chamber during the expansion stroke. It is characterized in that turbirence is generated to increase the combustion speed in the second combustion chamber.

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

In the figure, 1 is a cylinder, 2 is a cylinder head joined to the top of the cylinder, and inside the cylinder 1 is a piston 3.
is slidably inserted.

A protruding sub-piston part 3a is provided on the top of the piston 3, and the combustion chamber space formed in the cylinder head 2 is formed by a first sub-piston part 3a into which the sub-piston part 3a is fitted. It is divided into a combustion chamber 4 and a second combustion chamber 5 separated from the first combustion chamber 4 by fitting the auxiliary piston portion 3a therein.

The compartments of the first combustion chamber 4 and the second combustion chamber 5 are set to have different ratios (compression ratios) between the combustion chamber volume and the compression cross-sectional area.

This difference in compression ratio may be in either the first combustion chamber (or the second combustion chamber or the first combustion chamber) or the second combustion chamber.

A comb-like turbulence generating member 6 is provided between the first combustion chamber 4 and the second combustion chamber 5, located near the boundary between the compartments.

In the embodiment shown in FIGS. 1 and 2, a large number of turbulence generating members 6 are provided to protrude downward from the inner wall surface 2a of the cylinder head 2. As shown in the figure, it may be installed upright on the outer circumference of the top surface of the sub-piston part 3a, or as shown in FIG. However, as described above, the mixture flowing into the first combustion chamber or the flame flowing into the second combustion chamber collides with these many comb-shaped turbulence generating members 6 and is stirred. Formed in such a way that fine turbirence can occur.

Further, the turbulence generating member 6 is made in advance from the same kind of material as the cylinder head 2 or the piston 3, or from a different kind of material.
It may be cast or assembled, or it may be integrally formed during casting.

In addition, the spark plug 7 in the figure is provided in the first combustion chamber 4, and the second combustion chamber 5 is provided with an intake valve 8 and an exhaust valve 9, and this intake valve 5 is connected to the intake pipe. The exhaust valve 9 is connected to a carburetor 11 through the carburetor 10 so that the air-fuel mixture is sucked into the cylinder 1 from the carburetor 11, and an exhaust pipe 12 is connected to the exhaust valve 9. .

However, these intake valves 8 and exhaust valves 9 may be provided in the first combustion chamber 4.

With the configuration described above, the air-fuel mixture taken into the cylinder 1 is compressed in the first and second combustion chambers 4 and 5 as the piston 3 rises.

During this compression stroke, there is a difference in compression ratio between the two combustion chambers 4 and 5. For example, the compression ratio of the first combustion chamber 4 is different from that of the second combustion chamber 5.
If it is set smaller than that of It collides with a large number of comb-shaped turbulence generating members 6, is agitated, creates fine turbulence, and flows into the first combustion chamber.
Creates fine turbulence in the air-fuel mixture in the first combustion chamber,
This, together with the increase in the pressure of the air-fuel mixture, further improves the ignitability, and the energization of the spark plug 7 ensures ignition.

Also, when the sub-piston part 3a is pulled out of the first combustion chamber 4 by the descent of the piston 3 during the expansion stroke (at the end of the split period), the flame in the first combustion chamber 4 is directed toward the second combustion chamber 5. The ejected flame ignites the air-fuel mixture in the second combustion chamber 5, but in this process, the ejected flame collides with the turbulence generating member 6, where it is stirred and creates fine turbulence. Since the air-fuel mixture is generated and injected, the combustion speed of the air-fuel mixture in the second combustion chamber 5 is further improved, combustion occurs quickly, and output can be maximized.

Thus, according to the present invention, in the split combustion internal combustion engine described above, ignition is reliable even when using a lean mixture, and the combustion speed in the second combustion chamber can be increased, so that the output is 1 °C. NOx and CO, H without
It is possible to provide an internal combustion engine that can reduce both the exhaust harmful components of C.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional view showing one embodiment of the present invention, Fig. 2 is a transverse sectional view taken along the line A-A in Fig. 1, and Fig. 3 is a longitudinal sectional view showing another example of the formation of the turbulence generating member. 4 is a plan view of the piston, and FIG. 5 is a longitudinal sectional view of the top of the piston showing another example of the formation of the turbulence generating member. 1...Cylinder, 2...Cylinder head, 3...Piston, 3a...Sub-piston part, 4...First combustion chamber , 5... Second combustion chamber, 6... Turbulence generating member, 7...
・Spark plug, 8... Intake valve, 9...
Exhaust valve, 1o... suction pipe, 11... carburetor,
12...Exhaust pipe.

Claims (1)

[Scope of utility model registration request] The combustion chamber of an internal combustion engine is divided into a plurality of chambers at a predetermined period before and after top dead center by a piston with an auxiliary piston part protruding from the top, and ignition occurs in the first combustion chamber, causing the piston to move during its expansion stroke. Due to the lowering, the first combustion chamber becomes the second combustion chamber.
In a split combustion internal combustion engine, the air-fuel mixture in the second combustion chamber is torch ignited by the flame from the first combustion chamber immediately before or after the first and second combustion chambers are communicated with the first and second combustion chambers. A comb-like shape is provided near the boundary between the two combustion chambers in the cylinder head or at the top of the auxiliary piston section to create a fine turbulence in the air-fuel mixture or flame passing near the boundary. A combustion device for a split combustion internal combustion engine, comprising a turbulence generating member.