JPH05195785A - Combustion chamber of auxiliary combustion chamber type diesel engine - Google Patents

Abstract

PURPOSE:To generate sure mixing of the combustive expansion gas from a jet with the air by allowing the gas to produce a left and a right swirl, setting the centers of valve recesses approx. identical to the centers of the swirls, also furnishing another valve recess, and introducing the expansion gas to the two swirls and the third valve recess through an expansion gas guide groove and a straight advancing gas guide groove. CONSTITUTION:Combustive expansion gas from a jet 4 is so arranged as to generate a left and a right swirl 6, 7, and the centers 14, 15 of these swirls are made to lie approx, identical to the centers 16, 17 of valve recesses 10, 13. Another valve recess 37 is provided, and the expansion gas is guided through an expansion gas guide groove 40 and a straight-advancing gas guide groove 48 so as to ensure mixing with the air.

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. 7) and a technique disclosed in Japanese Utility Model Publication No. 61-13707 (see FIG. 7). 8)).

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 the above-mentioned prior art, the combustion performance is not significantly improved as compared with the case 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, it was not known at all where in the main combustion chamber the vortex windings 106 and 107 were generated.
I checked the location of 06.107. As a result, the injection port 104 is provided at a position eccentric from the cylinder center 103,
In the combustion chamber having a structure in which the auxiliary combustion chamber communicates with the main combustion chamber through the injection port 104, it has been discovered that the vortex centers 114 and 115 of the vortex windings 106 and 107 are generally located at specific places. That is, as illustrated in FIGS. 7 and 8,
Virtual longitudinal line 1 passing through the nozzle 104 and the center 103 of the cylinder
12 and a virtual transverse line 113 orthogonal to the cylinder center 103
Assuming that
On the 4th side, each vortex center 114 /
It was discovered that 115 was located.

Next, based on this finding, the inventor has found that the reason why the combustion performance is not improved in each of the above-mentioned prior arts is that the vortex winding 10
The position of each vortex center 114/115 and each recess center 116/117 were compared with each other, considering that there is a positional relationship between 6/107 and the valve recess 110/111. As a result, in each of the above-mentioned related arts, each recess center 116.117.
Are 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 inventor has found that the reason why the combustion performance is not improved in each of the above-mentioned prior arts is that each of the recess centers 116 and 117.
Does not coincide with the respective vortex centers 114 and 115, most of the air accumulated in the valve recesses 110 and 111 does not come into contact with the combustion expansion gas forming the vortex windings 106 and 107, so that these are reliably mixed. The inventors have found that the combustion performance can be improved by matching the recess centers 116 and 117 with the vortex centers 114 and 115, and have reached the present invention.

[0009]

In the present invention, as shown in FIG. 1, a fuel injection nozzle 2 faces a sub combustion chamber 1,
Combustion-expanded gas ejected from the auxiliary combustion chamber 1 through the injection port 4 by providing the 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 configured to form a pair of left and right spirals 6 and 7, and at least one of the piston head surface 8 and the cylinder head surface 9 facing the main combustion chamber 5 has a pair of left and right valve recesses. 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 FIG. 1 or FIGS. 4 to 6, a virtual longitudinal line 12 passing through the injection port 4 and the cylinder center 3 and a virtual transverse line 1 orthogonal to the cylinder center 3.
3 is assumed, the vortex center 14 of each of the vortex windings 6 and 7 located closer to the injection port 4 than the virtual transverse line 13 is.
・ The above-mentioned valve recess 10
11, the respective recess centers 16 and 17 of the valve recess 11 are set, and the combustion expansion gas guide groove is formed on the piston head surface 8 from the portion 41 facing the injection port 4 to the portions 42 and 43 of the valve recesses 10 and 11 near the virtual longitudinal line 12. 40 is recessed, and another valve recess 37 is recessed in the piston head surface 8 on the side farther from the injection port 4 than the respective valve recesses 10 and 11, and the straight gas 27 separated from the vortex windings 6 and 7 is introduced. The straight gas guide groove 48 for guiding is led out from the combustion expansion gas guide groove 40, and the other valve recess 3 is provided.
7 is tangentially connected.

[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 diffuses into the combustion expansion gas forming the spirals 6 and 7 as indicated by arrows 20 and 21 due to the difference in centrifugal force. In addition, the combustion expansion gas guide groove 40
Since it is guided with less resistance, the flow speed of the spiral windings 6 and 7 is high. For this reason, the air accumulated in the valve recesses 10 and 11 and the combustion expansion gas forming the vortex windings 6 and 7 are reliably mixed. Furthermore, the straight gas 27 is introduced tangentially into the other valve recess 37 through the straight gas guide groove 48 to form the spiral winding 49, so that the air accumulated in the other valve recess 37 and the straight gas 27 are mixed. Is certainly done.

[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,
Diffuse into combustion expansion gas. Moreover, the combustion expansion gas is
The flow velocity of the vortex winding is high because the resistance is guided by the combustion expansion gas guide groove. Therefore, the air accumulated in the valve recess is reliably mixed with the combustion expansion gas forming the whirlpool. Furthermore, since the straight-ahead gas is tangentially introduced into the other valve recess through the straight-ahead gas guide passage and forms a spiral here, the air accumulated in the other valve recess and the straight-ahead gas are reliably mixed. From the above,
Combustion performance is enhanced, which improves output performance and reduces fuel consumption.

Since the valve recess is arranged at a specific position and the combustion expansion gas guide groove and the straight gas guide groove are formed on the piston head surface, it can be manufactured by slightly changing the existing combustion chamber, and the manufacturing cost can be reduced. Is cheap.

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 line BB, FIG. 1C is a sectional view taken along line CC of FIG. 1A, and FIG. 1D is a sectional view taken along line DD of FIG. 1A. 1 (E) is a sectional view taken along the line EE of FIG. 1 (A). 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 auxiliary 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 combustion expanded gas, the difference in centrifugal force causes
The air diffuses into the combustion expanding gas forming the spirals 6 and 7 as shown by arrows 20 and 21, and the mixing of these is ensured.

Furthermore, in order to increase the flow velocity of the spirals 6 and 7,
A combustion expansion gas guide groove 40 is provided in the piston head surface 8. The combustion expansion gas guide groove 40 is fan-shaped and has a nozzle 4
The portion 41 facing with is the center of the fan, and the width thereof gradually increases and the depth thereof gradually decreases as the distance from the nozzle 4 increases along the virtual longitudinal line 12. The left and right portions of the combustion expansion gas guide groove 40 are
The pair of left and right valve recesses 10 and 11 are overlapped with the portions 42 and 43 near the vertical running lines 12. With 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 small resistance, and the flow velocity of the pair of left and right spirals 6 and 7 is increased.

Further, in order to ensure that the air accumulated in the front valve recess 37 and the straight gas 27 are mixed, a straight gas guide groove 40 for guiding the straight gas 27 is provided from the front end portion of the combustion expansion gas guide groove 40. It is led out and tangentially connected to the valve recess 37 on the front side. According to this structure, the straight gas 27 can be introduced tangentially into the front valve recess 37 through the straight gas guide groove 48, and the spiral winding 49 can be formed there, and the straight gas 27 can be collected in the front valve recess 37. Mixing of the air and the straight gas 27 is also reliably performed.

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 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 B-B of FIG. 4, and FIG. 4C is a sectional view taken along line CC of FIG.
4D is a cross-sectional view taken along the line DD of FIG. In this third embodiment, the piston head of the first embodiment shown in FIG. 1 is applied to a four-valve engine, and two straight gas 27 for branching and guiding the straight 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. 5 is a diagram for explaining a combustion chamber according to a fourth embodiment of the present invention, FIG. 5 (A) is a plan view of a piston head used in this combustion chamber, and FIG. 5 (B) is FIG. 5 (A). 5B is a sectional view taken along line BB in FIG. 5, and FIG. 5C is a sectional view taken along line CC in FIG.
FIG. 5D is a sectional view taken along the line D-D of FIG. The fourth embodiment is a combustion expansion gas guide groove 40 of the first embodiment shown in FIG.
Is formed in a rectangular shape along the virtual longitudinal line 12.
In the third embodiment, the combustion expanded gas guide groove 40 is formed in the injection port 4
It is formed so that the depth thereof gradually becomes shallower as it goes away from the injection port 4 along the virtual longitudinal line 12 from the portion 41 facing.

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 line BB of FIG. 6C, and FIG. 6C is a sectional view taken along line CC of FIG.
6D is a cross-sectional view taken along the line DD of FIG. In this fifth embodiment, the piston head of the fourth embodiment shown in FIG. 5 is applied to a four-valve engine, and two straight gas 27 for branching and guiding the straight gas 27 are branched from the front end portion of the combustion expansion gas guide groove 40. The guide grooves 48, 48 are led out, and these are connected tangentially to the two front-side valve recesses 37, 37.

The contents of the embodiment of the present invention are as described above, but the present invention is not limited to the above embodiment. 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]

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, and FIG. 1 (A) is a plan view of a cylinder head fitted in a cylinder;
1B is a sectional view taken along line BB in FIG. 1A, FIG. 1C is a sectional view taken along line CC in FIG. 1A, and FIG. 1D is D- in FIG. 1A. FIG. 1E is a sectional view taken along line D-E 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 diagram illustrating a combustion chamber according to a 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 in FIG. 4C, and FIG. 4C is a sectional view taken along line CC in FIG.
4D is a cross-sectional view taken along the line DD of FIG.

5 is a diagram illustrating a combustion chamber according to a fourth embodiment of the present invention, FIG. 5 (A) is a plan view of a piston head used in this combustion chamber, and FIG. 5 (B) is FIG. 5 (A). 5B is a sectional view taken along line BB in FIG. 5C, and FIG. 5C is a sectional view taken along line CC in FIG.
FIG. 5D is a sectional view taken along the line D-D of FIG.

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 the line BB of FIG. 6C, and FIG. 6C is a sectional view taken along the line CC of FIG.
6D is a cross-sectional view taken along the line DD of FIG.

FIG. 7 is a plan view of a piston head of a combustion chamber according to the related art.

FIG. 8 is a plan view of a piston head of a combustion chamber according to another related art.

[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 right and left 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 6 · 7, 16 · 17… each recess center of 10/11, 27… straight gas, 37 ... Front-side valve recess, 40 ... Combustion expansion gas guide groove, 41 ... 4 facing portion, 42, 43 ... 10
・ A part of 11 toward 12, 48 ... A straight gas guide groove.

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.
7) is set, and a portion (42) near the virtual longitudinal line (12) of each of the valve recesses (10) and (11) from the portion (41) facing the injection port (4).
・ Along with (43), a combustion expansion gas guide groove (40) is provided in the piston head surface (8), and on the side farther from the injection port (4) than the valve recesses (10) and (11).
Another valve recess (37) is provided in the piston head surface (8), and a straight gas (2) separated from the vortex windings (6) and (7) is formed.
The straight gas guide groove (48) for guiding 7) is led out from the combustion expansion gas guide groove (40) to provide the other valve recess.
A combustion chamber of a sub-combustion chamber type diesel engine, characterized in that it is tangentially connected to (37).