JPH05195782A - Combustion chamber of auxiliary combustion chamber type diesel engine - Google Patents

Abstract

PURPOSE:To generate sure mixing of combustion gas with air by locating the recess center of a valve recess in a position approx. identical to the center of swirl of the combustive expansion gas on the jet side of an intercepting line perpendicular to the line tying the jet to the center of cylinder. CONSTITUTION:Valve recesses 10, 11 are provided in at least either of a piston head and cylinder head so that the combustive expansion gas jetted out of a jet 4 forms swirls 6, 7 in a main combustion chamber. If an assumed intercepting line 13 is set which intersects at the center 3 of cylinder perpendicularly to the assumed longitudinally running line 12 tying the jet 4 to the center 3 of cylinder, then the centers 14, 15 of the swirls 6, 7 are made approx. identical to the centers 16, 17 of the valve recesses 10, 11. In this manner, the air is diffused in the combustive expansion gas to ensure the mixing operation.

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 secondary combustion chamber type diesel engine.

[0002]

2. Description of the Related Art Conventionally, as a combustion chamber of a secondary combustion chamber type diesel engine, a technique disclosed in Japanese Patent Laid-Open No. 58-138217 (see FIG. 14) and a technique disclosed in Japanese Utility Model Publication No. 61-13707 (FIG. 15)).

In these prior arts, the fuel injection nozzle faces the auxiliary combustion chamber, the injection port 104 is provided at a position eccentric from the cylinder center 103, and the auxiliary combustion chamber communicates with the main combustion chamber through the injection port 104. The combustion expansion gas ejected from the auxiliary combustion chamber through the injection port 104 is configured so as to form a pair of left and right spirals 106 and 107 in the main combustion chamber, and a pair of left and right sides is formed on the piston head surface 108 facing the main combustion chamber. The present invention relates to a combustion chamber in which the valve recesses 110 and 111 are recessed. And these are the valve recesses 110/11
It is intended to improve the combustion performance by bringing a large amount of air accumulated in No. 1 into contact with the combustion expansion gas forming the spirals 106 and 107 and mixing them.

[0004]

However, in these prior arts, there is no significant improvement in combustion performance as compared with those without the valve recesses 110 and 111. It is considered that the reason is that the air accumulated in the valve recesses 110 and 111 is not reliably mixed with the combustion expansion gas forming the spirals 106 and 107.

An object of the present invention is to reliably mix the air accumulated in the valve recess with the combustion expansion gas forming the spiral.

[0006]

BACKGROUND OF THE INVENTION In the past, since it was not known at all in the main combustion chamber where the spirals 106 and 107 were generated, the inventors first of all, prior to the present invention, of the spirals 106 and 107. I checked the place of occurrence. As a result, in a combustion chamber having a structure in which the injection port 104 is provided at a position eccentric from the cylinder center 103 and the auxiliary combustion chamber communicates with the main combustion chamber via the injection port 104, generally, the spiral windings 106, 107 are formed.
It has been found that each of the vortex centers 114 and 115 of is located at a specific place. That is, as illustrated in FIG. 14 and FIG. 15, when a virtual longitudinal line 112 passing through the injection port 104 and the cylinder center 103 and a virtual transverse line 113 orthogonal to the cylinder center 103 are assumed, the injection port is more than the virtual transverse line 113. It was discovered that the vortex centers 114 and 115 of the vortex windings 106 and 107 were located closer to 104.

Next, based on this finding, the inventors have found that the reason why the combustion performance is not improved in each of the above-mentioned prior arts is that the vortex winding 1
It is considered that there is a positional relationship between 06.107 and the valve recesses 110 and 111, and the positions of the vortex centers 114 and 115 and the recess centers 116 and 117 were compared. As a result, in each of the above-mentioned related arts, each recess center 116.117.
Is located on the virtual transverse line 113 or on the side farther from the injection port 104 than the virtual transverse line 113, and each vortex center 114.
It was confirmed that it was far from 115.

The inventors have found that the reason why the combustion performance is not improved in each of the above prior arts is that each recess center 116.
Since 7 does not match each vortex center 114/115,
It is noted that most of the air accumulated in the valve recesses 110 and 111 does not come into contact with the combustion expansion gas forming the spirals 106 and 107, and the mixing of these has not been reliably performed, while the recess center 116 is determined. It has been found that the combustion performance can be improved by matching 117 with the vortex centers 114 and 115, and the present invention has been achieved.

[0009]

In the present invention, as shown in FIG. 1, a fuel injection nozzle 2 is made to face a sub combustion chamber 1.
Combustion-expanded gas ejected from the auxiliary combustion chamber 1 through the injection port 4 by providing an injection port 4 at a position eccentric from the cylinder center 3 and communicating the auxiliary combustion chamber 1 with the main combustion chamber 5 through the injection port 4. However, the main combustion chamber 5 is formed so as to form a pair of left and right spirals 6 and 7, and a pair of left and right valve recesses is provided on at least one of the piston head surface 8 and the cylinder head surface 9 facing the main combustion chamber 5. In the combustion chamber of the sub-combustion chamber type diesel engine in which 10 and 11 are recessed, it is characterized as follows.

That is, as illustrated in FIGS. 1 and 4 to 13, a virtual longitudinal line 12 passing through the injection port 4 and the cylinder center 3 and a virtual transverse line 13 orthogonal to the cylinder center 3 are provided.
Assuming that
Center of each vortex of the above-mentioned vortex windings 6 and 7 located nearer
The valve recess 10.1
It is characterized in that the recess centers 16 and 17 of 1 are set.

[0011]

The operation of the present invention will be described with reference to FIG. In the present invention, the recess centers 16 and 17 are substantially aligned with the vortex centers 14 and 15, respectively.
The air accumulated in 11 is surrounded by the combustion expansion gas forming the spirals 6 and 7 from the surroundings and dragged by this.
Turn in the same direction as the spirals 6 and 7 as indicated by arrows 18 and 19. At this time, since the specific gravity of air is larger than that of the combustion expansion gas, the air is diffused into the combustion expansion gas forming the spirals 6 and 7 as shown by arrows 20 and 21 due to the difference in centrifugal force.
These are surely mixed.

[0012]

Since the center of each recess coincides with the center of each vortex, the air accumulated in the valve recess is surrounded by the combustion expansion gas that forms the vortex, and is dragged by the same to generate the same as the vortex. It turns in the direction and due to the centrifugal force difference,
Diffusion in the combustion expansion gas ensures their mixing. For this reason, combustion performance is enhanced, which improves output performance and reduces fuel consumption.

Since the valve recess is simply arranged at a specific position, it can be manufactured by slightly changing the existing combustion chamber, and the manufacturing cost is low.

Since the mixing performance of the air and the combustion expansion gas in the main combustion chamber is good, the temperature distribution of the combustion temperature in the main combustion chamber becomes more uniform, and the cylinder head, piston head, etc.
The thermal distortion of the part that constitutes the main combustion chamber is reduced, and the thermal damage and thermal deformation thereof are suppressed.

[0015]

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

The combustion chamber of the first embodiment is as follows. That is, as shown in FIG. 1B, the cylinder head 23 is assembled on the upper side of the cylinder 22, the piston head 24 is fitted in the cylinder 22, and the main combustion chamber 5 is formed in the cylinder 22. In the cylinder head 23, a substantially spherical vortex chamber type auxiliary combustion chamber 1 facing the fuel injection nozzle 2 is formed, and the auxiliary combustion chamber 1 is connected to the main combustion chamber 5 via an injection port 4. As shown in FIG. 1A, the injection port 4 is provided at a position eccentric from the cylinder center 3. As shown in FIG. 2, the injection port 4 is formed along the left and right sides of the main passage 25 that is provided in an oblique direction, and the side passage 2 that is a downward widening shape is formed.
6 and 26 are formed and configured.

In this combustion chamber, the combustion expansion gas ejected from the sub-combustion chamber 1 shown in FIG. 1 (B) through the injection port 4 has a pair of left and right sides in the main combustion chamber 5 as shown in FIG. 1 (A). Volute 6
・ Form 7. And each vortex center 14 ・ 15
Is located as follows: That is, assuming a virtual longitudinal line 12 passing through the injection port 4 and the cylinder center 3 and a virtual transverse line 13 orthogonal to the cylinder center 3, the virtual transverse line 13 is assumed.
The vortex centers 14 and 15 are located closer to the injection port 4 than.
In addition, a part of the combustion expansion gas ejected from the injection port 4 is separated into the vortex windings 6 and 7, and becomes a straight gas 27 that travels straight along the virtual longitudinal line 12.

Further, as shown in FIGS. 1 (B) and 1 (C),
An intake port 28 and an exhaust port 29 are formed in the cylinder head 23, and the two intake valve openings 3 of the intake port 28 are formed.
Two intake valves 32 and 33 are provided at 0 and 31 to open and close,
An exhaust valve 35 is provided at an exhaust valve port 34 of the exhaust port 29 so as to be openable and closable. This is a so-called three-valve structure. The intake / exhaust valves 32, 33, 35 are opened and closed at a predetermined timing via a valve operating device including a push rod 36 and the like. And these intake and exhaust valves 32, 33.3
As shown in FIG. 1 (A), a pair of left and right valve recesses 10 and 11 and a front valve recess 37 are recessed in the piston head surface 8 facing the main combustion chamber 5 at a position opposed to 5.

In this embodiment, as shown in FIG. 1A, in order to reliably mix the air accumulated in the pair of left and right valve recesses 10 and 11 with the combustion expansion gas forming the spirals 6 and 7. The recess centers 16 and 17 of the valve recesses 10 and 11 are set at positions closer to the injection port 4 than the virtual transverse line 13 and substantially coincident with the vortex centers 14 and 15 of the vortex windings 6 and 7. With this configuration,
The air accumulated in the valve recesses 10 and 11 is surrounded by the combustion expansion gas forming the spirals 6 and 7 from the surroundings, and is dragged by the combustion expansion gas, as shown by arrows 18 and 19 in the same direction as the spirals 6 and 7. Turn to. At this time, since the specific gravity of air is larger than that of the combustion expanded gas, due to the difference in centrifugal force,
The air diffuses into the combustion expansion gas forming the spirals 6 and 7 as shown by arrows 20 and 21, and the mixing of these is ensured.

The recess center 38 of the front valve recess 37 is set in the vicinity of the imaginary longitudinal line 12 through which the straight gas 27 passes. Therefore, the air accumulated in the valve recess 37 on the front side and the straight traveling gas 27 are effectively mixed.

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 pair of left and right valve recesses 10 and 11 of the first embodiment shown in FIG. It is formed on the cylinder head surface 9 facing the main combustion chamber 5.

FIG. 4 is a plan view of a piston head used in a combustion chamber according to the third embodiment of the present invention. The piston head 24 is of a two-valve engine, and is obtained by removing the front valve recess 37 from the piston head surface 8 of the first embodiment shown in FIG.

FIG. 5 is a plan view of a piston head used in a combustion chamber according to the fourth embodiment of the present invention. This piston head 24 is of a four-valve engine, and the diameter of the pair of left and right valve recesses 10 and 11 of the first embodiment shown in FIG. 1 is made slightly smaller to approach the injection port 4 side, and the front side valve recess 37 is a left and right pair. , The respective recess centers 38, 38 of the valve recesses 37, 37 on the front side, the recess centers 16 of the valve recesses 10, 11 near the injection port 4 with respect to the virtual transverse line 13.
It is set at a position line-symmetrical to 17. With such a configuration, the straight gas 27 collides with the inner peripheral surface of the cylinder 22 and is inverted, and enters the front-side valve recesses 37, 37 to form spirals 39, 39, and the respective valve recesses 37.
The mixing of the air accumulated in 7 with the straight gas 27 is also reliably performed.

FIG. 6 is a view for explaining a combustion chamber according to the fifth embodiment of the present invention, FIG. 6 (A) is a plan view of a piston head used in this combustion chamber, and FIG. 6 (B) is FIG. 6 (A). 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 combustion expansion gas guide groove 40 is provided in the piston head surface 8 of the first embodiment shown in FIG.

The combustion-expanded gas guide groove 40 is fan-shaped, and the portion 41 facing the injection port 4 is the core of the fan, and the virtual vertical running line 12 is provided.
The width is gradually increased and the depth is gradually decreased as the distance from the nozzle 4 is increased along. The left and right portions of the combustion expanded gas guide groove 40 are formed by the vertical running lines 12 of the pair of left and right valve recesses 10 and 11.
The central portion of the tip end of the combustion expansion gas guide groove 40 is overlapped with the side portions 42 and 43, and the front side valve recess 3 is formed.
It is overlapped with the portion 44 of the virtual crossing line 13 of 7. According to such a configuration, the combustion expansion gas ejected from the injection port 4 is guided by the combustion expansion gas guide groove 40 with a low resistance, the flow velocity of the pair of left and right spirals 6 and 7 and the straight gas 27 is increased, and the combustion expansion gas guide is formed. As compared with the embodiment 1 of FIG. 1 in which the groove 40 is not provided, the mixing of the air accumulated in all the valve recesses 10, 11, and 37 with the combustion expansion gas is further promoted.

FIG. 7 is a diagram for explaining a combustion chamber according to a sixth embodiment of the present invention, FIG. 7 (A) is a plan view of a piston head used in this combustion chamber, and FIG. 7 (B) is FIG. 7 (A). 7 is a sectional view taken along line BB of FIG. 7, FIG. 7C is a sectional view taken along line CC of FIG.
7D is a cross-sectional view taken along the line DD of FIG. The sixth embodiment is a combustion expansion gas guide groove 40 of the fifth embodiment shown in FIG.
Is formed in a bifurcated shape, and the combustion expansion gas is divided into vortex windings 6 and 7 and the straight gas 27. In front of the bifurcated front end portion 45 of the combustion expansion gas guide groove 40, a straight gas rising slope is formed via a rising portion 46. 47 is provided in a stepped shape.

According to such a configuration, the rising portion 4
Due to the resistance of 6, part of the straight gas 27 is swirled 6.7.
Since it is deflected to the side, the flow velocity of the spirals 6 and 7 increases, and there is no such deflecting means for the straight gas 27.
In comparison with the fifth embodiment, the pair of left and right valve recesses 10 and 11
The mixing of the air accumulated in the air with the combustion expansion gas forming the spirals 6 and 7 is further promoted.

FIG. 8 is a diagram for explaining a 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 combustion chamber, and FIG. 8 (B) is FIG. 8 (A). 8 is a sectional view taken along line BB of FIG. 8C, and FIG. 8C is a sectional view taken along line CC of FIG.
8D is a cross-sectional view taken along the line D-D of FIG. The seventh embodiment is a combustion expansion gas guide groove 40 of the fifth embodiment shown in FIG.
Is shortened, the straight gas guide groove 48 is led out from the front end portion of the combustion expanded gas guide groove 40, and this is connected tangentially to the valve recess 37 on the front side.

With this structure, the straight gas 27 can be introduced tangentially into the valve recess 37 on the front side through the straight gas guide groove 48, and the spiral winding 49 can be formed here. As compared with the fifth embodiment shown in FIG. 6 which does not have the groove 48, the mixing of the air accumulated in the front valve recess 37 and the straight gas 27 is further promoted.

FIG. 9 is a diagram for explaining a combustion chamber according to the eighth embodiment of the present invention, FIG. 9 (A) is a plan view of a piston head used in this combustion chamber, and FIG. 9 (B) is FIG. 9 (A). 9B is a sectional view taken along line BB of FIG. 9C, and FIG. 9C is a sectional view taken along line CC of FIG. 9A.
9D is a cross-sectional view taken along the line DD of FIG. 9A. In this ninth embodiment, the piston head of the seventh embodiment shown in FIG. 8 is applied to a four-valve engine, and two straight traveling gases 27 for branching and guiding the straight traveling gas 27 from the front end portion of the combustion expansion gas guide groove 40 are provided. The guide grooves 48, 48 are led out, and these are connected tangentially to the two front-side valve recesses 37, 37.

FIG. 10 is a diagram for explaining a combustion chamber according to a ninth embodiment of the present invention, FIG. 10 (A) is a plan view of a piston head used in this combustion chamber, and FIG. 10 (B) is FIG. 10 (A). B
-B line sectional drawing, FIG.10 (C) is CC sectional view taken on the line of FIG.10 (A). In the ninth embodiment, the combustion expansion gas guide groove 40 of the fifth embodiment shown in FIG. 6 is formed in a rectangular shape along the virtual longitudinal line 12. In the ninth embodiment, the combustion expansion gas guide groove 40 is formed so that the depth thereof becomes gradually shallower as the distance from the portion 41 facing the injection port 4 increases along the virtual longitudinal line 12. . The left and right portions of the combustion expanded gas guide groove 40 are the portions 42 and 43 of the pair of left and right valve recesses 10 and 11 which are close to the virtual vertical running lines 12.
It is in communication with.

FIG. 11 is a view for explaining a combustion chamber according to the tenth embodiment of the present invention, FIG. 11 (A) is a plan view of a piston head used in this combustion chamber, and FIG. 11 (B) is FIG. 11 (A). 11B is a cross-sectional view taken along the line BB of FIG.
FIG. 11D is a sectional view taken along line D-D of FIG. 11A. In the tenth embodiment, the ninth embodiment shown in FIG.
The combustion expansion gas guide groove 40 is formed in a bifurcated shape, and a straight gas rising slope 47 is provided in a stepwise manner on the front side of the bifurcated front end portion 45 of the combustion expansion gas guide groove 40 via a rising portion 46. ..

FIG. 12 is a view for explaining a combustion chamber according to the eleventh embodiment of the present invention, FIG. 12 (A) is a plan view of a piston head used in this combustion chamber, and FIG. 12 (B) is FIG. 12 (A). 12B is a cross-sectional view taken along the line BB of FIG. 12, and FIG. 12C is CC of FIG.
FIG. 12D is a sectional view taken along the line D-D of FIG. 12A. In this eleventh embodiment, the straight gas guide groove 4 extends from the front end portion of the combustion expansion gas guide groove 40 of the ninth embodiment shown in FIG.
8 is derived and connected tangentially to the front valve recess 37.

FIG. 13 is a diagram for explaining a combustion chamber according to a twelfth embodiment of the present invention, FIG. 13 (A) is a plan view of a piston head used in this combustion chamber, and FIG. 13 (B) is FIG. 13 (A). 13B is a cross-sectional view taken along the line BB of FIG.
FIG. 13D is a sectional view taken along the line DD of FIG. 13A. The twelfth embodiment corresponds to the eleventh embodiment shown in FIG.
This piston head 24 is applied to a four-valve engine, and the straight gas 2 is introduced from the front end portion of the combustion expansion gas guide groove 40.
Two straight gas guide grooves 48, 48 for branching and guiding 7 are led out, and these are connected tangentially to two front valve recesses 37, 37.

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, the auxiliary combustion chamber 1 may be a pre-combustion chamber type. Also,
The pair of left and right valve recesses 10 and 11 may be formed on both the piston head surface 8 and the cylinder head surface 9.

[Brief description of drawings]

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

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

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

FIG. 4 is a plan view of a piston head used in a combustion chamber according to a third embodiment of the present invention.

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

FIG. 6 is a diagram illustrating a 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 combustion chamber, and FIG. 6 (B) is FIG. 6 (A). 6B is a sectional view taken along line BB of FIG. 6C, and FIG. 6C is a sectional view taken along line CC of FIG.

FIG. 7 is a diagram illustrating a combustion chamber according to a sixth embodiment of the present invention, FIG. 7 (A) is a plan view of a piston head used in this combustion chamber, and FIG. 7 (B) is FIG. 7 (A). 7B is a sectional view taken along line BB in FIG. 7C, and FIG. 7C is a sectional view taken along line CC in FIG. 7A.
7D is a cross-sectional view taken along line DD of FIG.

8 is a diagram illustrating a 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 combustion chamber, and FIG. 8 (B) is FIG. 8 (A). 8B 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.
8D is a cross-sectional view taken along the line D-D of FIG.

9 is a diagram for explaining a combustion chamber according to an eighth embodiment of the present invention, FIG. 9 (A) is a plan view of a piston head used in this combustion chamber, and FIG. 9 (B) is FIG. 9 (A). 9B is a sectional view taken along the line BB of FIG. 9C, and FIG. 9C is a sectional view taken along the line CC of FIG. 9A.
9D is a cross-sectional view taken along the line DD of FIG. 9A.

10 is a diagram illustrating a combustion chamber according to a ninth embodiment of the present invention, FIG. 10 (A) is a plan view of a piston head used in this combustion chamber, and FIG. 10 (B) is FIG. 10 (A). ) B-
FIG. 10C is a sectional view taken along line B-C in FIG. 10A.

11 is a diagram illustrating a combustion chamber according to a tenth embodiment of the present invention, FIG. 11 (A) is a plan view of a piston head used in this combustion chamber, and FIG. 11 (B) is FIG. 11 (A). ) B
11B is a sectional view taken along line B-B, FIG. 11C is a sectional view taken along line CC of FIG. 11A, and FIG. 11D is a sectional view taken along line DD of FIG. 11A.

12 is a diagram illustrating a combustion chamber according to an eleventh embodiment of the present invention, FIG. 12 (A) is a plan view of a piston head used in this combustion chamber, and FIG. 12 (B) is FIG. 12 (A). ) B
12B is a sectional view taken along the line B-B, FIG. 12C is a sectional view taken along the line CC of FIG. 12A, and FIG. 12D is a sectional view taken along the line DD of FIG. 12A.

13 is a diagram illustrating a combustion chamber according to a twelfth embodiment of the present invention, FIG. 13 (A) is a plan view of a piston head used in this combustion chamber, and FIG. 13 (B) is FIG. 13 (A). ) B
13B is a sectional view taken along the line B-C, FIG. 13C is a sectional view taken along the line CC of FIG. 13A, and FIG. 13D is a sectional view taken along the line DD of FIG. 13A.

FIG. 14 is a plan view of a piston head of a combustion chamber according to the related art.

FIG. 15 is a plan view of a piston head of a combustion chamber according to another conventional technique.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Auxiliary combustion chamber, 2 ... Fuel injection nozzle, 3 ... Cylinder center, 4 ... Injection port, 5 ... Main combustion chamber, 6.7 ... A pair of left and right spirals, 8 ... Piston head surface, 9 ... Cylinder head surface, 1
0 · 11 ... a pair of left and right valve recesses, 12 ... virtual longitudinal line, 13 ... virtual transverse line, 14 * 15 ... each vortex center of 16/7, 16 * 17 ... each recess center of 11/11.

Claims (1)

[Claims] 1. A fuel injection nozzle (2) is made to face the auxiliary combustion chamber (1), an injection port (4) is provided at a position eccentric from the cylinder center (3), and the auxiliary combustion is performed through this injection port (4). Combustion expansion gas, which communicates the chamber (1) with the main combustion chamber (5) and is ejected from the auxiliary combustion chamber (1) through the injection port (4), has a pair of left and right vortices in the main combustion chamber (5). In addition to forming the windings (6) and (7), a pair of left and right valve recesses (10) are formed on at least one of the piston head surface (8) and the cylinder head surface (9) facing the main combustion chamber (5). ) ・ In the combustion chamber of the sub-combustion chamber type diesel engine in which (11) is recessed, a virtual longitudinal line passing through the injection port (4) and the cylinder center (3)
Virtual crossing line that is orthogonal to (12) and the center of the cylinder (3)
Assuming (13), the vortex centers (14) and (15) of the vortex windings (6) and (7), which are located closer to the injection port (4) than the virtual transverse line (13), are almost the same. At the matching positions, the recess centers (16) and (1) of the valve recesses (10) and (11), respectively.
A combustion chamber of a sub-combustion chamber type diesel engine characterized by setting 7).