JPH06221161A - Auxiliary chamber type combustion chamber of diesel engine - Google Patents

Abstract

PURPOSE:To feed a greater amount of combustion expansion gas to the a large valve recess side where an air containing amount is high and to uniformize a mixture ratio between gas and air by a method wherein the diameter of a side injection nozzle on the large valve recess side is set to a value higher than that of a side injection nozzle on the small valve recess. CONSTITUTION:An injection nozzle 3 through which main and auxiliary combustion chambers 1 and 2 are intercommunicated comprises a main injection nozzle 4 and two side injection nozzles 5 and 6 on both sides. Left and right valve recesses 9 and 10 having different diameters are formed at least in one of a piston head surface 7 fronting on the main combustion chamber 1 and a cylinder head surface 8. Right and left heat flows of combustion expansion gas injected through the injection nozzle 3 are caused to flow toward the left and right valve recesses 9 and 10. In this case, the diameter of the side injection nozzle 6 on the large valve recess 10 side is set to a value higher than that of the side injection nozzle 5 on the small valve recess 9 side. The center 14 of the large valve recess 10 is arranged in a position situated more away from the injection nozzle 3 than the center 13 of the small valve recess 9.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sub-combustion type combustion chamber of a diesel engine, and more particularly to a sub-combustion type combustion chamber capable of promoting uniformization of the mixing ratio of combustion expansion gas and air in the main combustion chamber.

[0002]

2. Description of the Related Art FIG. 9 shows a conventional technique of a sub-chamber type combustion chamber of a diesel engine. Like the present invention, it has the following basic structure. That is, the injection port 103 that connects the main combustion chamber and the auxiliary combustion chamber is composed of the main injection port 104 and the left and right side injection ports 105 and 106 provided on both left and right sides of the main injection port 104, and on the piston head surface 107 facing the main combustion chamber, Left and right valve recesses 109 and 110 with different diameters are recessed, and the injection port 1
Left and right side jets 111 of combustion expansion gas ejected from 03
112 is configured to face the left and right valve recesses 109 and 110.

In the sub-chamber type combustion chamber having such a basic structure, the combustion expansion gas generated by the premixed combustion in the sub-combustion chamber becomes the central jet 115 and the left and right side jets 111 and 112 from the nozzle 103. Eject into the main combustion chamber. The central jet 115 goes straight in the main combustion chamber,
12 forms a pair of left and right vortex flows in the main combustion chamber. And
Diffusion combustion is performed in the main combustion chamber by mixing the combustion expansion gas with the air in the main combustion chamber.

By the way, in this prior art, the left and right side jet nozzles 105 and 106 have the same diameter, and the valve recess 11 having a large diameter is used.
The recess center 114 of 0 is arranged farther from the injection hole 103 than the recess center 113 of the valve recess 109 having a small diameter.

[0005]

The above-mentioned conventional techniques have the following problems. Since the left and right side jet holes 105 and 106 have the same diameter, the jetting amounts of the left and right side jet flows 111 and 112 are almost the same, and the small-diameter valve recess 109 is also provided on the large-diameter valve recess 110 side.
The same amount of combustion expansion gas is also supplied to the side. Therefore, the mixing ratio of the combustion expansion gas and air is biased toward the air excess side on the large diameter valve recess 110 side where the air storage amount is large, and is biased toward the gas excess side on the small diameter valve recess 109 side where the air storage amount is small. As described above, the mixing ratio of the combustion expansion gas and the air in the main combustion chamber varies depending on the size of the diameter of the valve recess, which is a factor that deteriorates the combustion performance.

Since the right and left side jets 105 and 106 have the same diameter, the flow velocities of the left and right side jets 111 and 112 are substantially the same, and the vortex centers 116 and 117 of the left and right vortex flows formed by the left and right side jets 111 and 112. Are located at substantially the same distance from the injection port 103, but the recess center 114 of the large-diameter valve recess 110 is located at the small-diameter valve recess 1.
Since it is arranged farther from the nozzle 103 than the recess center 113 of 09, the vortex centers 116 and 117 of the jets 111 and 112 on the left and right sides are at the same time.
It cannot match 4. Also, the left and right side jets 11
It is also difficult to locate the vortex centers 116 and 117 of 1.112 near the recess centers 113 and 114 at the same time. Therefore, at least one of the vortex center 117 is greatly separated from the recess center 114, and the valve recess 1
The air accumulated inside 10 was not reliably entrained in the vortex flow of the side jet 112, and the utilization of air in the main combustion chamber was lowered, which was also a factor that deteriorates the combustion performance.

The first and second inventions have a common object to promote uniformization of the mixing ratio of the combustion expansion gas and air in the main combustion chamber in the sub-chamber type combustion chamber of the diesel engine. In addition to the above-mentioned subject, the 2nd invention makes it a subject to promote utilization of air in a main combustion chamber.

[0008]

[Means for Solving the Problems]

(First Invention) As shown in FIGS. 1 to 3, the first invention is a left and right side where a main injection port 4 and an injection port 3 communicating with each other are provided on the main injection port 4 and on both sides thereof. Left and right valve recesses 9 and 10 having different diameters are formed in at least one of the piston head surface 7 and the cylinder head surface 8 which face the main combustion chamber 1 and are ejected from the injection port 3. Right and left side jets 11 and 12 of combustion expansion gas are left and right valve recesses 9.
-A sub-chamber combustion chamber of a diesel engine configured to face 10 is characterized by the following.

That is, as illustrated in FIGS. 1 to 8,
It is characterized in that the diameter of the side injection port 6 on the side of the large-diameter valve recess 10 is made larger than the diameter of the side injection port 5 on the side of the small-diameter valve recess 9 side.

(Second Invention) In the second invention, as shown in FIGS. 1 to 6, in the first invention, the recess center 14 of the large-diameter valve recess 10 is made larger than the recess center 13 of the small-diameter valve recess 9. It is characterized in that it is arranged away from the injection port 3.

[0011]

[Action]

(First Invention) As illustrated in FIGS. 1 to 8, the diameter of the side nozzle hole 6 on the side of the large-diameter valve recess 10 is made small.
Since the diameter is made larger than the diameter of the side jet nozzle 5 on the side, the jet amount of the side jet 12 to the side of the large diameter valve recess 10 is large, and the jet amount of the side jet 11 to the side of the small diameter valve recess 9 is small.
Therefore, a large amount of combustion expansion gas is correspondingly supplied to the large-diameter valve recess 10 side having a large air storage amount, and a corresponding large combustion expansion gas is supplied to the small-diameter valve recess 9 side having a small air storage amount. As a result, the difference in the mixing ratio of the combustion expansion gas and air in the main combustion chamber 1 caused by the size of the diameter of the valve recess is reduced, and the combustion expansion gas and air in the main combustion chamber 1 are separated. Uniformization of the mixing ratio is promoted.

(Second invention) In addition to the operation of the first invention, it operates as follows. As illustrated in FIGS. 1 to 6, since the diameter of the side jet orifice 6 on the side of the large diameter valve recess 10 is made larger than the diameter of the side jet nozzle 5 on the side of the small diameter valve recess 9, the side portion to the side of the large diameter valve recess 10 is narrowed. The jet velocity of the jet 12 is high, and the jet velocity of the side jet 11 toward the valve recess 9 side having a small diameter is slow. Therefore, the side jet 1 on the side of the large-diameter valve recess 10
Side vortex 1 on the side of valve recess 9 where vortex center 17 of 2 is small
Although it will be farther from the nozzle 3 than the vortex center 16 of 1, the recess center 14 of the large-diameter valve recess 10 is arranged further away from the nozzle 3 than the recess center 13 of the small-diameter valve recess 9. There is a jet flow 1 on both sides
The vortex centers 16 and 17 of 1 and 12 can be positioned at the same time or at positions near the recess centers 13 and 14 of the left and right valve recesses 9 and 10 at the same time. Therefore, the air in the left and right valve recesses 9 and 10 is reliably entrained in the left and right side jet flows 11 and 12, and the utilization of air in the main combustion chamber 1 is increased.

[0013]

【The invention's effect】

(First Invention) A large amount of combustion expansion gas is correspondingly supplied to the large diameter valve recess side having a large air storage amount, and a small amount of combustion expansion gas is correspondingly supplied to the small diameter valve recess side having a small air storage amount. Since it is supplied, uniformization of the mixing ratio of the combustion expansion gas and air in the main combustion chamber is promoted. Therefore, the combustion performance can be improved.

(Second Invention) In addition to the effects of the first invention, the following effects are exhibited. The vortex center of the left and right side jet flows can be positioned at a position substantially coincident with the recess center of the left and right valve recesses or a position in the vicinity thereof. Therefore, the air inside the left and right valve recesses is reliably entrained in the jet flows on the left and right sides,
Increased air utilization in the main combustion chamber. Therefore, the combustion performance can be further enhanced.

[0015]

Embodiments of the present invention will be described with reference to the drawings.
1 is a diagram for explaining a sub-chamber combustion chamber of a diesel engine according to a first embodiment of the present invention, FIG. 1 (A) is a plan view of a cylinder head fitted in a cylinder, and FIG. 1 (B) is a diagram. 1
FIG. 1A is a cross-sectional view taken along the line BB of FIG. 1A, and C of FIG.
It is a -C line sectional view. FIG. 2 is a schematic diagram of an injection port used in the sub-chamber type combustion chamber of FIG.

The structure of the combustion chamber of the first embodiment is as follows. That is, as shown in FIG.
Cylinder head 19 is assembled on the upper side of
A piston head 20 is fitted in the cylinder 8 and a main combustion chamber 1 is formed in the cylinder 18. In the cylinder head 19,
A substantially spherical vortex chamber type auxiliary combustion chamber 2 facing the fuel injection nozzle 21 is formed, and the main combustion chamber 1 and the auxiliary combustion chamber 2 are connected to the injection port 3
It is in communication with. As shown in FIG. 1A, the injection port 3 is provided at a position eccentric from the cylinder center 22. As shown in FIG. 2, this injection port 3 is a main injection port 4 formed in an oblique direction.
And the left and right side jet nozzles 5 and 6 provided on both the left and right sides. In this combustion chamber, the combustion expansion gas generated by the premixed combustion in the auxiliary combustion chamber 2 shown in FIG.
As shown in (A), a central jet 15 and left and right side jets 11 and 12 are jetted from the jet port 3 into the main combustion chamber 1. The central jet 15 goes straight inside the main combustion chamber 1
2 forms a pair of left and right eddy flows in the main combustion chamber 1. And
Diffusion combustion is performed in the main combustion chamber 1 by mixing the combustion expansion gas with the air in the main combustion chamber 1.

This engine is of a two-valve type and is shown in FIG.
As shown in (C), an intake port 23 and an exhaust port 24 are provided in the cylinder head 19, an intake valve 26 is openably and closably provided at an intake valve port 25 of the intake port 23, and an exhaust valve port 27 of the exhaust port 24 is provided. An exhaust valve 28 is provided so as to be freely opened and closed. The intake valve 26 and the exhaust valve 28 are opened and closed at a predetermined timing via a valve operating device including a push rod 29 shown in FIG. And FIG.
As shown in (A) and (C), left and right valve recesses 9 and 10 having different diameters are recessed in the piston head surface 7 facing the main combustion chamber 1 at a position facing the intake valve 26 and the exhaust valve 28. , Left and right side jets 11 and 12 have left and right valve recesses 9.1
It is configured to go to 0. Large diameter valve recess 1
0 is for the intake valve 26, and the small-diameter valve recess 9 is for the exhaust valve 28.

In this embodiment, in order to promote uniformization of the mixing ratio of the combustion expansion gas and air in the main combustion chamber 1,
(A) or as shown in FIG. 2, a large-diameter valve recess 1
The diameter of the side injection port 6 on the 0 side is made larger than the diameter of the side injection port 5 on the side of the valve recess 9 having a small diameter. For this reason, the ejection amount of the side jet flow 12 toward the large-diameter valve recess 10 side is large, and the ejection amount of the side jet flow 11 toward the small-diameter valve recess 9 side is small. Therefore, the large-diameter valve recess 1 with a large air capacity
Correspondingly, a large amount of combustion expansion gas is supplied to the 0 side,
A small amount of combustion expansion gas is supplied to the side of the small-sized valve recess 9 having a small amount of air accommodated, so that the mixing ratio of the combustion expansion gas and air in the main combustion chamber caused by the size of the valve recess is small. The difference becomes smaller and the mixing ratio of the combustion expansion gas and air in the main combustion chamber 1 is promoted to be uniform.

Further, in this embodiment, in order to promote the utilization of air in the main combustion chamber 1, as shown in FIG. 1 (A), the recess center 14 of the large-diameter valve recess 10 is replaced with a small-diameter valve recess. The vortex center 16 of the left side jet 11 is substantially aligned with the recess center 13 of the small-diameter valve recess 9 and the vortex center 17 of the right side jet 12 is large in diameter. It is located near the recess center 14 of the valve recess 10. Therefore, the air in the left and right valve recesses 9 and 10 is reliably entrained in the left and right side jet flows 11 and 12, and the utilization of air in the main combustion chamber 1 is increased. The air accumulated in the left and right valve recesses 9 and 10 is surrounded by the vortex of the left and right side jets 11 and 12 from the surroundings, and is dragged by the spirals in the same direction as the left and right side jets 11 and 12 as indicated by arrows 30 and 31. To turn. At this time, since the specific gravity of air is larger than that of the combustion expanded gas, the air is jetted to the left and right side jet flows 11 as indicated by arrows 32 and 33 due to the difference in centrifugal force.
• Diffuses in 12 and mixes smoothly.

FIG. 3 is a view corresponding to FIG. 1C of a combustion chamber according to a second embodiment of the present invention. In this second embodiment, the left and right valve recesses 9 and 10 of the first embodiment shown in FIG. Intake valve opening 25 and exhaust valve opening 2 of the cylinder head surface 8 facing the chamber 1
It is formed at position 7.

FIG. 4 is a diagram for explaining a combustion chamber according to the third embodiment of the present invention, FIG. 4 (A) is a plan view of a piston head used in this combustion chamber, and FIG. 4 (B) is FIG. 4 (A). 4B is a sectional view taken along line BB, and FIG. 4C is a sectional view taken along line CC of FIG. In the third embodiment, the combustion expansion gas guide groove 34 is provided in the piston head surface 7 of the first embodiment shown in FIG.

The combustion expansion gas guide groove 34 is fan-shaped, and the portion 35 facing the injection port 3 is the core of the fan. As the distance from the injection port 3 increases, the width thereof gradually increases and the depth thereof gradually decreases. Has been formed. The left and right portions of the combustion expanded gas guide groove 34 are formed in the left and right valve recesses 9.
・ Connected to 10. Therefore, the combustion expansion gas ejected from the injection port 3 is guided by the combustion expansion gas guide groove 34 with less resistance, and the flow velocity of the combustion expansion gas is increased as compared with the first embodiment of FIG. 1 in which the combustion expansion gas guide groove 34 is not provided. The mixing of the air in the combustion chamber 1, particularly the air in the left and right valve recesses 9 and 10 with the combustion expansion gas is further promoted.

FIG. 5 is a plan view of a piston head used in a sub-chamber combustion chamber according to a fourth embodiment of the present invention. The sub-chamber type combustion chamber of Example 4 is of a three-valve engine equipped with a single exhaust valve (not shown) and two intake valves (not shown).
Contrary to the first embodiment shown in FIG. 1, on the piston head surface 7, a small-diameter valve recess 9 is arranged on the right side and a large-diameter valve recess 10 is arranged on the left side. Further, a valve recess 36 having a small diameter is arranged on the front side. The single large-diameter valve recess 10 is for an exhaust valve, and the two small-diameter valve recesses 9 and 36 are for an intake valve. Also,
In the fourth embodiment, as in the first embodiment shown in FIG. 1, the diameter of the side injection port 6 on the side of the large-diameter valve recess 10 is made larger than the diameter of the side injection port 5 on the side of the small-diameter valve recess 9 side. Also,
The recess center 14 of the large-diameter valve recess 10 is arranged farther from the injection port 3 than the recess center 13 of the small-diameter valve recess 9, and the vortex centers 16 and 17 of the left and right side jets 11 and 12 are the recess centers of both valve recesses 9 and 10. It is almost the same as 13 ・ 14.

FIG. 6 is a diagram for explaining a sub-chamber type combustion chamber according to a fifth embodiment of the present invention, FIG. 6 (A) is a plan view of a piston head used in this sub-chamber type combustion chamber, and FIG. 6 (B). Is shown in FIG.
6B is a sectional view taken along the line BB of FIG. 6C, and FIG. 6C is a sectional view taken along the line CC of FIG. In the fifth embodiment, the fourth embodiment shown in FIG.
A combustion expansion gas guide groove 34 is provided in the piston head surface 7 of the above. The combustion expansion gas guide groove 34 has the same structure as the combustion expansion gas guide groove 34 of the third embodiment shown in FIG.

FIG. 7 is a plan view of a piston head used in a sub-chamber type combustion chamber according to a sixth embodiment of the present invention. The sub-chamber type combustion chamber of the sixth embodiment is of a four-valve engine equipped with two exhaust valves (not shown) and two intake valves (not shown). The large diameter valve recesses 10 and 38 are arranged on the left side, and the two small diameter valve recesses 9 and 37 are arranged on the left side. Large diameter valve recess 10.3
Reference numeral 8 is for an intake valve, and valve recesses 9 and 37 having a small diameter are for an exhaust valve. In the sixth embodiment, a large diameter recess connecting axis 42 connecting the recess centers 14 and 40 of the large diameter valve recesses 10 and 38 and a small diameter recess connecting axis 41 that connects the recess centers 13 and 39 of the small diameter valve recesses 9 and 37. And the valve recesses 9 and 3 with large diameters and valve recesses 9 and 3 with small diameters so that
7 and 7 are arranged. Also, the large diameter valve recess 10
The diameter of the side injection port 6 on the 38 side is set to a small diameter valve recess 9.37.
It is made larger than the diameter of the side jet nozzle 5 on the side. The recess center 14 of the large-diameter valve recess 10 and the recess center 13 of the small-diameter valve recess 9 on the side close to the injection port 3 are arranged equidistant from the injection port 3. Further, the recess center 40 of the large diameter valve recess 38 on the side far from the injection port 3 and the small diameter valve recess 37.
The recess center is located equidistant from the injection port 3.

In the sixth embodiment, since the large-diameter valve recess 10 and the small-diameter valve recess 9 can be arranged side by side on the side closer to the injection port 3, the combustion expansion is larger than when the large-diameter valve recess is arranged side by side. The mixing ratio of gas and air can be made more uniform.

That is, in the case of a four-valve engine, when the large-diameter valve recesses are arranged side by side on the side closer to the injection port, the recess clearance becomes narrower, so most of the combustion expansion gas ejected from the injection port has a large diameter. The combustion expansion gas that flows into the valve recess and escapes through the recess to the front side may be extremely reduced. Therefore, the mixture ratio of the combustion expansion gas and air tends to be biased toward the gas excess side on the valve recess side near the injection port and biased toward the air excess side on the valve recess side far from the injection port.

On the other hand, in the sixth embodiment, since the large-diameter valve recess 10 and the small-diameter valve recess 9 can be arranged laterally side by side on the side closer to the injection port 3, the recess gap 43 can be formed larger. . Therefore, sufficient combustion expansion gas is supplied also to the valve recesses 37 and 38 side far from the injection port, and the mixing ratio of the combustion expansion gas and air can be made more uniform regardless of the distance difference between the valve recess positions from the injection port 3. The valve recess 37 on the side far from the nozzle 3
A sufficient amount of the combustion expansion gas that has gone straight through the wide recess gap 43 drops into the valve 38, and this winds a vortex along the peripheral walls of the valve recesses 37 and 38. Therefore, the vortex centers 46 and 47 of the vortex flows in the valve recesses 37 and 38 substantially coincide with the recess centers 39 and 40.

In addition, in the sixth embodiment, as in the other embodiments, the diameter of the side injection port 6 on the side of the large diameter valve recesses 10 and 38 is smaller than that of the side injection port 5 on the side of the smaller diameter valve recesses 9 and 37. Since it is made large, the mixing ratio of the combustion expansion gas and air can be made more uniform regardless of the size of the valve recess diameter. In the sixth embodiment, as described above, the mixing ratio of the combustion expansion gas and the air in the main combustion chamber can be made more uniform, regardless of the distance between the valve recess position from the injection port 3 and the size of the valve recess diameter. The vortex centers 16 and 17 of the right and left side jets 11 and 12 are the recess centers 1 of the valve recesses 9 and 10.
It is located at a position substantially coincident with 3 · 14 or in the vicinity thereof.

FIG. 8 is a view for explaining a sub-chamber type combustion chamber according to a seventh embodiment of the present invention, FIG. 8 (A) is a plan view of a piston head used in this sub-chamber type combustion chamber, and FIG. 8 (B). Is shown in FIG.
8B is a sectional view taken along line BB, FIG. 8C is a sectional view taken along line CC of FIG. 8A, and FIG. 8D is a sectional view taken along line DD of FIG. In the seventh embodiment, a combustion expansion gas guide groove 34 is provided in the piston head surface 7 of the sixth embodiment shown in FIG.

The combustion expansion gas guide groove 34 extends from the portion 35 facing the injection port 3 to the left and right valve recesses 9 near the injection port.
It is formed into a fan shape over 10. The combustion expansion gas guide groove 34 has a portion 35 facing the injection port 3 as a corner of a fan, and as the distance from the injection port 3 increases, its width gradually increases and its depth gradually decreases. Then, the left and right valve recesses 9 and 10 close to the injection port 3
From the recess gap 43 of the fork-shaped diversion guide grooves 44, 45
Has been derived.

As the shunt guide grooves 44 and 45 are separated from the injection port 3, the depth thereof is gradually reduced. The two flow dividing guide grooves 44 and 45 are tangentially connected to the left and right valve recesses 37 and 38 on the side far from the injection port 3, respectively. The width of the diversion guide groove 45 connected to the large diameter valve recess 38 is made larger than the width of the diversion guide groove 44 connected to the small diameter valve recess 37, so that the partial flow rate of the combustion expansion gas to the large diameter valve recess 38 is increased. It is designed to be larger than the partial flow rate of the combustion expansion gas to the valve recess 37 having a small diameter.

Also in this embodiment, the left and right side jets 11.
The vortex centers 16 and 17 of 2 are located at positions that are substantially coincident with the recess centers 13 and 14 of the valve recesses 9 and 10 or in the vicinity thereof. In addition, valve recesses 37 and 38
The vortex center 46.47 of the vortex inside is the recess center 39.4.
It almost matches 0.

The contents of the embodiments of the present invention are as described above, but the present invention is not limited to the above embodiments.
For example, in each of the embodiments, the auxiliary combustion chamber 2 is of the vortex chamber type, but it may be of the precombustion chamber type. Further, in each embodiment, the valve recess is formed on either the piston head surface 7 or the cylinder head surface 8.
Valve recesses may be formed on both the piston head surface 7 and the cylinder head surface 8.

[Brief description of drawings]

FIG. 1 is a diagram illustrating a sub-chamber combustion chamber of a diesel engine according to a first embodiment of the present invention, FIG. 1 (A) is a plan view of a cylinder head fitted in a cylinder, and FIG. Figure 1
FIG. 1A is a cross-sectional view taken along the line BB of FIG. 1A, and C of FIG.
It is a -C line sectional view.

FIG. 2 is a schematic view of an injection port used in the sub-chamber type combustion chamber of FIG.

FIG. 3 is a diagram of a sub-chamber combustion chamber according to a second embodiment of the present invention.
(C) It is a corresponding figure.

4A and 4B are diagrams illustrating a sub-chamber combustion chamber according to a third embodiment of the present invention, FIG. 4A is a plan view of a piston head used in the sub-chamber combustion chamber, and FIG. 4A is a sectional view taken along line BB, and FIG. 4C is a sectional view taken along line CC of FIG.

FIG. 5 is a plan view of a piston head used in a sub-chamber type combustion chamber according to a fourth embodiment of the present invention.

6A and 6B are views illustrating a sub-chamber combustion chamber according to a fifth embodiment of the present invention, FIG. 6A is a plan view of a piston head used in the sub-chamber combustion chamber, and FIG. 6A is a sectional view taken along line BB, and FIG. 6C is a sectional view taken along line CC of FIG.

FIG. 7 is a plan view of a piston head used in a sub-chamber combustion chamber according to a sixth embodiment of the present invention.

8A and 8B are views for explaining a sub-chamber type combustion chamber according to a seventh embodiment of the present invention, FIG. 8A is a plan view of a piston head used in this combustion chamber, and FIG. 8B is FIG. 8A. 8) is a sectional view taken along line BB in FIG. 8C, and FIG. 8C is a sectional view taken along line CC in FIG. 8A.
FIG. 8D is a sectional view taken along the line DD of FIG.

FIG. 9 is a plan view of a piston head of a sub-chamber combustion chamber of a diesel engine according to a conventional technique.

[Explanation of symbols]

1 ... Main combustion chamber, 2 ... Sub combustion chamber, 3 ... Injection port, 4 ... Main injection port,
5.6 ... Left and right side nozzles, 7 ... Piston head surface, 8 ... Cylinder head surface, 9/10 ... Left and right valve recesses, 11/1
2 ... Jets on the left and right sides, 13 ・ 14… 9/10 recess center.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Manabu Miyazaki 64 Ishizukitamachi, Sakai City, Osaka Prefecture Kubota Sakai Co., Ltd.

Claims (2)

[Claims] 1. A main injection port (4) and left and right side injection ports (5), (6) provided on the left and right sides of the main injection port (4) are provided with injection ports (3) communicating the main combustion chamber (1) and the auxiliary combustion chamber (2). ), The left and right valve recesses (9) and (10) having different diameters are provided in at least one of the piston head surface (7) and the cylinder head surface (8) facing the main combustion chamber (1), In the sub-chamber type combustion chamber of a diesel engine configured so that the left and right side jets (11) and (12) of the combustion expansion gas ejected from the nozzle (3) are directed toward the left and right valve recesses (9) and (10), respectively. A secondary chamber combustion of a diesel engine, characterized in that the diameter of the side injection port (6) on the side of the large valve recess (10) is made larger than the diameter of the side injection port (5) on the side of the small valve recess (9). Room. 2. The sub-chamber type combustion chamber of the diesel engine according to claim 1, wherein the recess center (14) of the large-diameter valve recess (10) is larger than the recess center (13) of the small-diameter valve recess (9). A sub-chamber combustion chamber for a diesel engine, which is arranged away from the injection port (3).