JP2838743B2 - Combustion chamber of sub-combustion chamber diesel engine - Google Patents

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 sub-combustion chamber type diesel engine.

[0002]

2. Description of the Related Art Conventionally, as a combustion chamber of a sub-combustion chamber type diesel engine, a technique disclosed in Japanese Patent Application Laid-Open No. 58-138217 (see FIG. 3 ) and a technique disclosed in Japanese Utility Model Publication No. 61-13707 ( FIG. 4 ).

In these prior arts, a fuel injection nozzle faces a sub-combustion chamber, an injection port 104 is provided at a position eccentric from a cylinder center axis 103, and the sub-combustion chamber communicates with the main combustion chamber via the injection port 104. The combustion expansion gas ejected from the sub-combustion chamber through the injection port 104 is configured to form a pair of left and right spirals 106 and 107 in the main combustion chamber, and a pair of left and right is formed on a piston head surface 108 facing the main combustion chamber. The present invention relates to a combustion chamber in which valve recesses 110 and 111 are provided. And these are the valve recesses 110
・ Large amount of air and vortex 106.1 accumulated in 111
07 is made to come into contact with a combustion expansion gas which forms 07, and by mixing these, it is intended to improve combustion performance.

[0004]

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

SUMMARY OF THE INVENTION It is an object of the present invention to reliably mix air accumulated in a valve recess with a combustion expansion gas forming a spiral.

[0006]

In the prior art, it was not known at all where the spirals 106 and 107 occur in the main combustion chamber. I checked the location where it occurred. As a result, the injection chamber 104 is provided at a position eccentric from the cylinder center axis 103, and in the combustion chamber having a structure in which the sub combustion chamber communicates with the main combustion chamber via the injection port 104, generally, the spirals 106 and 10 are provided.
It has been found that each of the vortex centers 114 and 115 of No. 7 is located at a specific location. That is, as illustrated in FIGS. 3 and 4 , when viewed in a direction parallel to the cylinder center axis 103, a virtual vertical running line 112 passing through the injection port 104 and the cylinder center axis 103 and a virtual transverse line orthogonal to the cylinder center axis 103. Assuming that the whirlpool 113 is located closer to the injection nozzle 104 than the virtual transverse line 113,
4.115 was located.

[0007] 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 1
Assuming that there is a positional relationship between 06.107 and the valve recesses 110 and 111, the positions of the respective vortex centers 114 and 115 and the respective recess centers 116 and 117 were compared. As a result, in each of the above prior arts, each recess center 116 and 117
Are located on the virtual traversing line 113 or on the side farther from the injection port 104 than the virtual traversing line 113, and each vortex center 114.
It was confirmed that the value deviated significantly from 115.

The inventors have 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 11
7 is largely deviated from each of the swirl centers 114 and 115, much of the air accumulated in the valve recesses 110 and 111 does not come into contact with the combustion expansion gas forming the swirls 106 and 107, and the mixing thereof is ensured. While noting that there was a point that had not been
It has been found that the combustion performance can be improved by making 7 sufficiently coincident with or sufficiently close to the vortex centers 114 and 115, and the present invention has been achieved.

[0009]

According to the present invention, as illustrated in FIG. 1, a fuel injection nozzle 2 faces a sub-combustion chamber 1 and an injection port 4 is provided at a position eccentric from a cylinder center axis 3, and this injection port is provided. The auxiliary combustion chamber 1 is communicated with the main combustion chamber 5 through the auxiliary combustion chamber 4, and the combustion expansion gas ejected from the auxiliary combustion chamber 1 via the injection port 4 is supplied to the main combustion chamber 5 by a pair of left and right spirals 6. 7 and a pair of left and right valve recesses 10 and 11 formed in at least one of the piston head surface 8 and the cylinder head surface 9 facing the main combustion chamber 5 to burn the diesel engine. The room is characterized as follows.

That is, as illustrated in FIG. 1, when viewed in a direction parallel to the cylinder center axis 3, a virtual vertical running line 12 passing through the injection port 4 and the cylinder center axis 3 and a virtual vertical line perpendicular to the cylinder center axis 3. Assuming the traversing line 13, the virtual vertical running line 1
By setting the respective recess centers 16 and 17 of the pair of valve recesses 10 and 11 on the left and right sides of the pair 2, the pair of spiral windings 6 located on the injection port 4 side with respect to the virtual transverse line 13.
7 so that the respective vortex centers 14 and 15 are located within the pair of valve recesses 10 and 11, and the cylinder center axis 3
When viewed in a direction parallel to
The intake valve that allows the intake valve 33 to enter
The lubrication recess 37 is provided.
The center of the recess comes on the virtual vertical line 12 and
The recess center 38 of the
So that the piston head face 8 has a fan-shaped combustion expansion
The gas guide groove 40 is recessed, and the portion 41 facing the nozzle 4 is
The main point of the fan, looking parallel to the cylinder axis 3,
As the distance from the spout 4 increases, the width gradually increases.
In both cases, the depth is gradually reduced without any steps
When viewed in a direction parallel to the cylinder center axis 3, the combustion expansion
The left and right portions of the upholstery gas guide groove 40 are a pair of left and right valve recesses.
10 and 11, each section 42 and 43 near the vertical line 12
Burlap, center of the tip of combustion expansion gas guide groove 40
The minute is near the imaginary transverse line 13 of the intake valve recess 37.
It is characterized by overlapping with the portion 44.

[0011]

The present invention has the following functions and effects (see FIG. 1 ). The inventors have discovered the following prior to the present invention. That is, in a combustion chamber having a structure in which the injection port 4 is provided at a position eccentric from the cylinder center axis 3 and the sub combustion chamber 1 communicates with the main combustion chamber 5 via the injection port 4, regardless of the position of the valve recesses 10 and 11. A pair of left and right spirals 6 and 7 are generated in the main combustion chamber 5, and the respective spiral centers 14 and 15 are formed.
Is located closer to the injection port 4 than the virtual transverse line 13. The spiral windings 6 and 7 are provided with valve recesses 10 and 11 having a small radius of curvature.
The speed is higher than that of a spiral wound depending on a valve recess formed while receiving a large flow resistance due to the guide of the inner peripheral surface of the coil.

In the present invention, based on the above findings, a pair of recess centers 16 and 17 are set on the left and right sides of the imaginary vertical running line 12 on the side of the injection port 4 with respect to the imaginary traversing line 13, whereby Each vortex center 14 and 15 was located in a pair of valve recesses 10 and 11. In this way, the center 14 of each of the high-speed spirals 6 and 7
15 and the center of each of the recesses 16 and 17 can be made coincident or sufficiently close to each other. For this reason, the air collected in the pair of 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 air, and the arrow 18 moves in the same direction as the spirals 6 and 7.・ Turning at high speed like 19 Since the specific gravity of the air is greater than that of the combustion expansion gas, due to the difference in centrifugal force, the air becomes
As shown in FIG. 21, the gas diffuses into the combustion expansion gas forming the spirals 6 and 7, and the air in the pair of left and right valve recesses 10 and 11 is diffused.
Mixing with the combustion expansion gas is ensured.

According to the present invention, a fan-shaped
A combustion expansion gas guide groove 40 is provided, and
As the width gradually increases, the depth increases.
No difference, it is formed so that it gradually becomes shallow, and the left and right parts
Overlap with a pair of left and right valve recesses 10 and 11
I'm making it. By doing so, the fuel injected from the nozzle 4
The burning expansion gas passes through the fuel expansion gas guide groove 40,
If it spreads smoothly left and right without being disturbed by the inner wall
In both cases, the speed is increased by the throttle effect due to the inclination of the inner bottom.
The right and left overlay of the fuel expansion gas guide groove 40
Pair of left and right spirals to pass through the
The speed of 6.7 is kept high and a pair of left and right valve recesses
The mixture of air and fuel expansion gas accumulated in 10.11 is
It is done efficiently.

In the present invention, the air is sucked at a position away from the injection port 4.
An intake valve recess 37 for injecting the valve 33 is provided,
This intake valve recess 37 is imaginary in the center of the recess.
Comes on the vertical line 12 and its recess center 38 is virtual
It was arranged so as to come off the vertical running line 12. this
As a result, the high purity air in the intake valve recess 37 is removed.
Air and straight gas passing through the center of the recess are in long contact
The straight gas that has passed through the center of the recess
When it collides with the peripheral wall surface of the valve recess 37, the peripheral wall surface
The air in the intake valve recess 37
Mixing with the fuel expansion gas is ensured. Note that the intake
The reason that the purity of the air in Lubricess 37 is high is that
The combustion gas remaining in the cylinder after the process is
Therefore, the air is scavenged from the vicinity of the intake valve recess 37.
is there.

According to the present invention, a fan-shaped
A combustion expansion gas guide groove 40 is provided, and
As the width gradually increases, the depth increases.
Without any difference, it is formed so that it gradually becomes shallow, and the combustion expansion gas
The central portion of the tip of the inner groove 40 is in contact with the intake valve recess 37.
-Overlapping. If this is done,
The combustion expansion gas injected from the fuel expansion gas guide groove 40
Smooth left and right without being disturbed by the inner wall surfaces
The gas 27 spreads straight and a pair of right and left spirals 6.7
Separates smoothly from the squeeze and creates a diaphragm effect due to the inclination of the inner bottom surface
Therefore, while increasing the speed, the tip of the fuel expansion gas guide groove 40 is
In order to smoothly pass through the end overlap,
The speed of the advancing gas 27 is kept high, and the intake valve recess 3
Mixing air and fuel expansion gas accumulated in 7 efficiently
Done.

[0016]

An embodiment of the present invention will be described with reference to the drawings.
First, a first embodiment will be described. FIG. 1 shows an embodiment of the present invention.
A diagram illustrating a combustion chamber of the auxiliary combustion chamber type diesel engine according to the embodiment, FIG. 1 (A) is a plan view of a cylinder head which is fitted in the cylinder, FIG. 1 (B) Figure 1 (A) B- 1 (C) is a sectional view taken along line CC of FIG. 1 (A), and FIG.
FIG. 2D is a sectional view taken along line DD of FIG. FIG. 2 is a schematic view of an injection port used in the combustion chamber of FIG.

The combustion chamber of this embodiment is as follows. That is, as shown in FIG.
Assemble the cylinder head 23 on the upper side of the cylinder 2
2, the main combustion chamber 5 is formed in the cylinder 22. In the cylinder head 23,
A substantially spherical swirl type auxiliary combustion chamber 1 facing a fuel injection nozzle 2 is formed, and the auxiliary combustion chamber 1 is connected to a 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 center 3 of the cylinder. As shown in FIG. 2, the injection port 4 is formed along the left and right sides of a main passage 25 provided in an oblique direction, and a lower-side expanded side passage 26.
26 are formed.

In this combustion chamber, as shown in FIG. 1A, a combustion expansion gas ejected from the auxiliary combustion chamber 1 shown in FIG. Vortex 6
Form 7. And each vortex center 14 ・ 15
Is located as follows. That is, assuming a virtual vertical running line 12 passing through the injection port 4 and the cylinder center axis 3 and a virtual crossing line 13 orthogonal to the cylinder center axis 3 when viewed in a direction parallel to the cylinder center axis 3, The vortex centers 14 and 15 are also located near the nozzle 4. Further, a part of the combustion and expansion gas ejected from the injection port 4 is divided into the spiral windings 6 and 7 to become the straight gas 27 that travels straight along the virtual vertical running line 12.

As shown in FIGS. 1B and 1C,
An intake port 28 and an exhaust port 29 are formed in the cylinder head 23, and two intake valve ports 3 of the intake port 28 are formed.
The two intake valves 32 and 33 are provided at 0.31 to open and close freely,
An exhaust valve 35 is provided at an exhaust valve port 34 of the exhaust port 29 so as to be freely opened and closed. This is a so-called three-valve structure. The intake / exhaust valves 32, 33, and 35 are opened and closed at a predetermined timing via a valve train including a push rod 36 and the like. And these intake and exhaust valves 32, 33.3
As shown in FIG. 1A, a pair of left and right valve recesses 10 and 11 and a front valve recess 37 are formed in the piston head surface 8 facing the main combustion chamber 5 at a position facing the main combustion chamber 5.

In this embodiment, as shown in FIG. 1A, in order to surely 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. A pair of left and right valve recesses 1 is provided on the left and right sides of the virtual vertical running line 12 on the side of the injection port 4 with respect to the virtual crossing line 13.
The center of each of the recesses 16 and 17 of the valve recesses 10 and 11 is defined by setting the center of each of the recesses 0.11 and 1. 17 is set so as to substantially match. In such a 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 this, and is drawn in the same direction as the spirals 6 and 7. Then, the vehicle turns as indicated by arrows 18 and 19. At this time, since the specific gravity of the 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 indicated by arrows 20 and 21 due to the difference in centrifugal force, and the mixture of these airs is mixed. Is performed reliably.

In the direction parallel to the cylinder center axis 3
As seen, a position farther from the nozzle 4 than the cylinder center axis 3
, An intake valve recess 37 for allowing the intake valve 33 to enter.
The intake valve recess 37 is located at the center of the recess.
Part is on the virtual vertical line 12 and its recess center 3
8 is located off the virtual vertical line 12
It is. Therefore, the mixing between the air collected in the intake valve recess 37 and the straight gas 27 is also improved.

In this embodiment, a fan-shaped combustion expansion gas guide groove 40 is formed in the piston head surface 8 so that a portion 41 facing the injection port 4 is a key of the fan, and viewed in a direction parallel to the cylinder center axis 3. As the distance from the nozzle 4 along the imaginary vertical running line 12 increases, the width thereof gradually increases, and the depth thereof gradually decreases without a step. When viewed in a direction parallel to the cylinder center axis 3, the left and right portions of the combustion expansion gas guide groove 40 overlap the portions 42 and 43 of the pair of left and right valve recesses 10 and 11 near the vertical running lines 12, respectively. The central portion of the leading end of the guide groove 40 overlaps a portion 44 of the intake valve recess 37 near the imaginary transverse line 13. 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 low resistance, the flow rates of the pair of left and right spirals 6 and 7 and the straight gas 27 are increased, and the combustion expansion gas guide is provided. Compared to the case without groove 40, all valve recesses 10.1
Mixing of the air accumulated in 1.37 with the combustion expansion gas is further promoted.

Although the contents of the embodiment of the present invention are as described above, 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 left and right pair of valve recesses 10 and 11 are cylinder heads.
Face 9, or piston head face 8 and cylinder head face 9
May be formed on both.

[Brief description of the drawings]

FIG. 1 is a view for explaining a combustion chamber of a sub-combustion chamber type diesel engine according to an 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 line BB of FIG. 1A, FIG. 1C is a sectional view taken along line CC of FIG . 1A , and FIG. 1D is a sectional view of FIG.
It is DD sectional drawing .

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

FIG. 3 is a plan view of a piston head of a combustion chamber according to the prior art .
FIG.

FIG. 4 shows a piston head of a combustion chamber according to another prior art .
It is a top view.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Sub combustion chamber, 2 ... Fuel injection nozzle, 3 ... Cylinder center axis line, 4 ... Injection port, 5 ... Main combustion chamber, 6. 7 ... Left and right pair of spirals, 8 ... Piston head surface, 9 ... Cylinder head surface,
10 ・ 11 ・ ・ ・ A pair of left and right valve recesses 、 12 ・ ・ ・ Virtual vertical running line 、 13 ・ ・ ・ Virtual crossing line 、 14 ・ 15 ・ ・ ・ 6.7 ・ 7 each vortex center 、 16 ・ 17 ・ ・ ・ 10 ・ 11 each recess center 、 27 ・ ・ ・ Straight gas 、 30, 31 ... intake valve opening, 33 ... intake valve, 37 ...
Intake valve recess, 40 ... Expansion gas guide groove, 41 ... Start end, 42/43 ... Partition near virtual imaginary running line.

Continuation of the front page (56) References JP-A-58-91326 (JP, A) JP-A-1-257714 (JP, A) JP-A-63-104634 (JP, A) JP-A-1-104914 (JP) , A) Japanese Utility Model Showa 55-132320 (JP, U) Japanese Utility Model Utility Model Hei 2-64720 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) F02B 1/00-23/10

Claims (1)

(57) [Claims] 1. A fuel injection nozzle (2) facing a sub-combustion chamber (1), and an injection port located at a position eccentric from a cylinder center axis (3).
(4), the sub-combustion chamber (1) communicates with the main combustion chamber (5) through the injection port (4), and the injection port is formed from the sub-combustion chamber (1).
The combustion expansion gas ejected through (4) flows into the main combustion chamber.
(5) A pair of left and right spirals (6) and (7) are formed, and at least a piston head surface (8) and a cylinder head surface (9) facing the main combustion chamber (5). In the combustion chamber of a sub-combustion chamber type diesel engine having a pair of left and right valve recesses (10) and (11) recessed on one side, when viewed in a direction parallel to the cylinder center axis (3),
A virtual vertical line (12) passing through (4) and the cylinder center axis (3)
And an imaginary transverse line (1) orthogonal to the cylinder center axis (3).
Assuming 3), the center of each recess of the pair of valve recesses (10) and (11) is located on both the left and right sides of the virtual vertical running line (12) on the side of the nozzle (4) above this virtual transverse line (13). (16)
・ By setting (17), the center of each of the vortices (14) and (15) of the pair of spirals (6) and (7) located closer to the injection port (4) than the virtual transverse line (13) is The pair of valve recesses
(10) and (11), and look in a direction parallel to the cylinder center axis (3).
The intake valve is located farther from the injection port (4) than the mandrel (3).
The intake valve recess (37) for invading the valve (33) is provided,
This intake valve recess (37) is temporarily
Comes on the vertical line (12) and its recess center (38)
Is positioned off the virtual vertical line (12)
And a fan-shaped combustion expansion gas guide groove (4) on the piston head surface (8).
0) is recessed, and the part (41) facing the nozzle (4) is
And viewed in a direction parallel to the cylinder center axis (3),
As we move away from (4), the width will gradually increase
Formed so that its depth is gradually reduced without any steps
When viewed in a direction parallel to the cylinder center axis (3), the combustion expansion
The left and right portions of the upholstery gas guide groove (40) are
Seth (10), (11) each vertical running line (12) leaning part (42)
(43), and the combustion expansion gas guide groove (4
0) is located at the center of the tip of the intake valve recess (37).
Virtual horizontal break (13) inner portion (44) overlapped
In addition, a diesel engine with a sub-combustion chamber
Combustion chamber .