JP2929056B2 - Sub-chamber combustion chamber for 4-valve 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 sub-chamber type combustion chamber of a four-valve diesel engine, and more particularly to a combustion chamber capable of promoting a uniform mixing ratio of combustion expansion gas and air in a main combustion chamber.

[0002]

2. Description of the Related Art FIG. 5 shows a prior art of a sub-chamber type combustion chamber of a four-valve diesel engine. This has the following basic structure as in the present invention. That is, the main combustion chamber and the sub-combustion chamber communicate with each other at the injection port 103, and the piston head surface 104 facing the main combustion chamber is provided with two large-diameter valve recesses 107 and 108 concentric with the two large-diameter valve ports. The small-diameter valve port and the concentric small-diameter valve recesses 110 and 111 are recessed,
The combustion expansion gas ejected from the injection port 103 has large-diameter valve recesses 107 and 108 and small-diameter valve recesses 110 and 111.
It is configured to go to.

In the sub-chamber combustion chamber having such a basic structure, the combustion expansion gas generated by the premixed combustion in the sub-combustion chamber becomes a central jet 121 and left and right side jets 122 and 123 from an injection port 103. Spouts into the main combustion chamber. The center jet 121 goes straight in the main combustion chamber, and the left and right side jets 122.1
23 forms a pair of left and right vortices in the main combustion chamber. And
This combustion expansion gas is mixed with air in the main combustion chamber, whereby diffusion combustion is performed in the main combustion chamber.

In the prior art, the nozzle 103
The large-diameter valve recesses 107 and 108 are provided side by side at positions close to the nozzle, and the small-diameter valve recesses 110 and 111 are provided at right and left side at positions far from the nozzle 103.

[0005]

The above prior art has the following problems. Since the large-diameter valve recesses 107 and 108 are provided side by side at a position close to the injection port 103, the recess interval 124 becomes narrow. Therefore, the nozzle 103
Most of the combustion expansion gas escaping from the valve is large-diameter valve recess 1
07.108, and the amount of combustion expansion gas flowing out from the recess gap 124 to the front side thereof may be extremely small. For this reason, the mixing ratio of the combustion expansion gas and air tends to be biased toward the gas excess side on the side of the large-diameter valve recesses 107 and 108 close to the injection port 103, and tends to be biased toward the excess air side on the small-diameter valve recesses 110 and 111 far from the injection port 103. is there. As described above, the difference in the distance between the valve recess position and the injection port 103 tends to cause a difference in the mixing ratio between the combustion expansion gas and the air in the main combustion chamber, which is a factor that deteriorates the combustion performance.

An object of the present invention is to promote uniformization of the mixing ratio of combustion expansion gas and air in a main combustion chamber in a sub-chamber type combustion chamber of a four-valve diesel engine.

[0007]

According to the present invention, as shown in FIGS. 1 to 4, a main combustion chamber 1 and a sub-combustion chamber 2 communicate with each other through an injection port 3, and a piston head surface facing the main combustion chamber 1 is provided. 4 and at least one of the cylinder head surfaces 5, two large-diameter valve recesses 7.8 are formed corresponding to the two large-diameter intake valves 32, and two small-diameter exhaust valves 33 are formed. Correspondingly, two small-diameter valve recesses 10 and 11 are recessed so that the combustion expansion gas ejected from the nozzle 3 is directed to the large-diameter valve recesses 7.8 and the small-diameter valve recesses 10 and 11. The following is a feature of the sub-chamber type combustion chamber of the engine.

That is, as exemplified in FIGS.
The injection port 3 is constituted by a main injection port 12 and left and right side injection ports 13 and 14 provided on both left and right sides thereof.
Two large-diameter valve recesses 7 and 8 are provided on one side and two small-diameter valve recesses 10 and 11 are provided on the other side, and two large-diameter valve recesses 7 are provided. A large-diameter recess connection axis 17 connecting the recess centers 15 and 16 of 8 and a small-recess connection axis 20 connecting the recess centers 18 and 19 of the two small-diameter valve recesses 10 and 11 face the injection port 3. The large-diameter valve recesses 7.8 and the small-diameter valve recesses 10 and 11 are arranged so as to expand in a C-shape, and the diameter of the side injection port 14 on the side of the large-diameter valve recess 7.8 is adjusted to the small-diameter valve recess 10. The diameter is larger than the diameter of the side jet port 13 on the 11th side.

[0009]

The present invention operates as follows, for example, as shown in FIGS. That is, by arranging the large-diameter valve recess 7 and the small-diameter valve recess 10 side by side with respect to the injection port 3, for example, the diameter of the intake valve 32 is increased in order to quickly supply air to the main combustion chamber 1. Accordingly, even if the diameter of the large-diameter valve recess 7 is increased, the diameter of the small-diameter valve recess 10 located on the side of the large-diameter valve recess 7 is
The recess gap 24 can be made wider by an amount corresponding to the smaller exhaust valve 33. Therefore, nozzle 3
The combustion inflation gas ejected from the
From the nozzle hole 3 and is sufficiently supplied to the valve recesses 8 and 11 located far from the nozzle hole 3. As a result, the difference in the mixing ratio between the combustion expansion gas and the air caused by the difference in the position of the valve recess from the injection port 3 becomes smaller.

Further, the diameter of the side jet port 14 on the side of the large-diameter valve recesses 7 and 8 is changed to the side jet port 1 on the side of the small-diameter valve recesses 10 and 11.
3, larger diameter valve recess 7.8
The side jet 23 has a large amount of jet to the side, and the small-diameter valve recess 1
The ejection amount of the side jet 22 toward the 0.11 side is reduced. Accordingly, a large amount of the combustion expansion gas is supplied to the large-diameter valve recesses 7 and 8 having a large air capacity, and the small-diameter valve recesses 10 and 11 having a small air capacity are correspondingly supplied. A small amount of combustion expansion gas is supplied. For this reason,
The difference in the mixing ratio between the combustion expansion gas and the air caused by the size of the valve recess diameter can be reduced.

As described above, the difference in the position of the valve recess from the injection port 3 and the difference in the mixing ratio between the combustion expansion gas and the air caused by the size of the valve recess can be reduced, so that the combustion in the main combustion chamber 1 can be reduced. It is possible to promote the uniformity of the mixing ratio between the inflation gas and air, and to enhance the combustion performance.

[0012]

The present invention has the following effects because it is constructed and operates as described above. That is, since the large-diameter valve recess and the small-diameter valve recess are arranged side by side with respect to the injection port, even if the diameter of the large-diameter valve recess is large, the diameter of the small-diameter valve recess is reduced in accordance with the diameter of the exhaust valve. In addition, it is possible to sufficiently secure a recess gap between the large-diameter valve recess and the small-diameter valve recess. Therefore, a sufficient amount of combustion expansion gas is supplied to the valve recess at a position far from the injection port, and the mixing ratio of the combustion expansion gas and air in the main combustion chamber can be made uniform, whereby the combustion performance can be improved. In other words, both a point that a sufficient recess gap can be ensured and a point that the diameter of the intake valve can be increased to improve the air supply efficiency can be achieved. As described above, the large-diameter valve recess having a large air capacity is located on one side and the small-diameter valve recess having a small air capacity is located on the other side of the left and right sides of the nozzle as described above. Although the amount of storage differs, the diameter of the side outlet of the large-diameter valve recess side nozzle is correspondingly larger than the diameter of the side nozzle of the small-diameter valve recess side nozzle. The combustion expansion gas according to the amount can be distributed to the left and right in the main combustion chamber. Therefore, the mixing ratio of the combustion expansion gas and air is prevented from being different between the left and right sides in the main combustion chamber, and the combustion efficiency is further improved.

[0013]

An embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a view for explaining a sub-chamber type 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 inside a cylinder, and FIG. 1
1A is a cross-sectional view taken along the line BB, and FIG.
FIG. 4 is a sectional view taken along line C of FIG. FIG. 2 is a schematic view of an injection port used in the sub-chamber type combustion chamber of FIG.

The construction of the sub-chamber type combustion chamber of the first embodiment is as follows. That is, as shown in FIG. 1 (B), the cylinder head 26 is assembled on the cylinder head 26, the piston head 27 is fitted on the cylinder 25, and the cylinder 25
A main combustion chamber 1 is formed therein. A substantially spherical swirl-type sub-combustion chamber 2 facing the fuel injection nozzle 28 is formed in the cylinder head 26, and the main combustion chamber 1 and the sub-combustion chamber 2 communicate with each other through an injection port 3. As shown in FIG. 1A, the injection port 3 is provided at a position eccentric from the cylinder center 29.
As shown in FIG. 2, the nozzle 3 has a main nozzle 12 formed in an oblique direction and left and right side nozzles 13 and 14 provided on both left and right sides thereof.
It consists of

In this sub-chamber type combustion chamber, the combustion expansion gas generated by the premixed combustion in the sub-combustion chamber 2 shown in FIG. Jet 2
1 and the right and left side jets 22 and 23 are jetted into the main combustion chamber 1. The center jet 21 goes straight in the main combustion chamber 1, and the left and right side jets 22 and 23 form a pair of left and right vortex flows in the main combustion chamber 1. Then, the combustion expansion gas is mixed with the air in the main combustion chamber 1 to perform diffusion combustion in the main combustion chamber 1.

This engine is of a four-valve type.
As shown in (C), an intake port 30 and an exhaust port 31 are provided in the cylinder head 26, and intake valves 32 are provided at two large-diameter valve ports 6 before and after the intake port 30 so as to be openable and closable. An exhaust valve 33 is provided at each of the two small diameter valve openings 9 before and after 31 so as to be freely opened and closed. This intake valve 32
And the exhaust valve 33 are provided with a push rod 34 shown in FIG.
The valve is opened and closed at a predetermined timing via a valve operating device composed of the same. As shown in FIGS. 1 (A) and 1 (B), two large-diameter valve recesses 7 concentric with two large-diameter valve ports 6 are provided on a piston head surface 4 facing the main combustion chamber 1.
8 and two small-diameter valve recesses 10 and 11 concentric with the two small-diameter valve openings 9, and the combustion expansion gas ejected from the injection port 3 is used for the large-diameter valve recesses 7.8 and the small-diameter valve recesses. It is configured to go to 10.11.

In this embodiment, large-diameter valve recesses 7 and 8 are provided on the right side of the main combustion chamber 1 in order to reduce the difference in the mixing ratio between the combustion expansion gas and the air caused by the difference in the valve recess position from the injection port 3. A large-diameter recess connecting axis 17 connecting the center 15 and 16 of each of the large-diameter valve recesses 7 and 8;
Recess center 18/19 of small diameter valve recess 10/11
The large-diameter valve recesses 7 and 8 and the small-diameter valve recesses 10 and 11 are arranged so that the small-diameter recess connection axis 20 connecting them to each other expands in a C-shape toward the injection port 3. The recess center 15 of the large-diameter valve recess 7 on the side close to the nozzle 3 and the recess center 18 of the small-diameter valve recess 10 are arranged at the same distance from the nozzle 3, and the recess center 16 of the large-diameter valve recess 8 on the side far from the nozzle 3. The recess center 11 of the small-diameter valve recess 11 is arranged at an equal distance from the injection port 3.

As described above, the large-diameter valve recess 7 and the small-diameter valve recess 10 can be arranged side by side on the side close to the injection port 3, and the recess gap 24 is made wider than when the large-diameter valve recesses are arranged side by side. be able to.
For this reason, the combustion expansion gas ejected from the injection port 3 easily passes through the wide recess gap 24, and a sufficient combustion expansion gas is supplied to the large-diameter valve recess 8 and the small-diameter valve recess 11 far from the injection port 3. For this reason, the difference in the mixing ratio between the combustion expansion gas and the air caused by the difference in the position of the valve recess from the injection port can be reduced. In addition, a part of a sufficient amount of the combustion expansion gas that has passed straight through the wide recess gap 43 falls into the valve recesses 3 and 11 farther from the injection port 3, and this wraps around the peripheral wall of the valve recesses 8 and 11. . For this reason, the respective vortex centers 39 and 40 of the vortex in the valve recesses 8 and 11 substantially coincide with the recess centers 16 and 19.

Further, in this embodiment, in order to reduce the difference in the mixing ratio between the combustion expansion gas and the air caused by the size of the valve recess, the diameter of the side injection port 14 on the side of the large-diameter valve recess 7.8 is reduced. The diameter is larger than the diameter of the side injection port 13 on the valve recess 10/11 side. For this reason, the amount of the side jets 23 ejected toward the large-diameter valve recesses 7 and 8 is large, and the amount of the side jets 22 ejected toward the small-diameter valve recesses 10 and 11 is reduced. Accordingly, much of the combustion expansion gas is supplied to the large-diameter valve recesses 7 and 8 having a large air capacity, and the small-diameter valve recesses 10 and 10 having a small air capacity are supplied.
Correspondingly, a small amount of combustion expansion gas is supplied to the 11 side. For this reason, the difference in the mixing ratio between the combustion expansion gas and the air caused by the size of the valve recess diameter can be reduced. The vortex centers 41 and 42 of the left and right side jets 22 and 23
Is located at a position substantially coinciding with or near the recess center 18/15 of the valve recess 10.7.

As described above, in this embodiment, since the difference in the position of the valve recess from the injection port 3 and the difference in the mixing ratio between the combustion expansion gas and air caused by the size of the valve recess can be reduced, the main combustion chamber can be reduced. It is possible to promote the uniformity of the mixing ratio between the combustion expansion gas and the air within 1, thereby improving the combustion performance.

FIG. 3 is a view corresponding to FIG. 1C of a sub-chamber type combustion chamber according to a second embodiment of the present invention.
The large-diameter valve recesses 7.8 and the small-diameter valve recesses 10 and 11 of the first embodiment are formed at positions of the large-diameter valve port 6 and the small-diameter port 9 on the cylinder head surface 5 facing the main combustion chamber 1.

FIG. 4 is a view for explaining a sub-chamber type combustion chamber according to Embodiment 3 of the present invention. FIG. 4 (A) is a plan view of a piston head used in the sub-chamber type combustion chamber, and FIG. 4 (B). Is FIG. 4 (A)
4 (C) is a sectional view taken along line CC of FIG. 4 (A), and FIG. 4 (D) is a sectional view taken along line DD of FIG. 4 (A). In the third embodiment, a combustion expansion gas guide groove 35 is formed in the cylinder head surface 5 of the first embodiment shown in FIG.

The combustion expansion gas guide groove 35 extends from a portion 36 facing the injection port 3 to a large-diameter valve recess 7 near the injection port 3.
And a small diameter valve recess 10 to form a fan shape. The combustion expansion gas guide groove 35 has a portion 36 facing the injection port 3 serving as a fan, and as the distance from the injection port 3 increases,
It is formed so that its width gradually increases and its depth gradually decreases.

From the recess gap 24 between the large-diameter valve recess 7 and the small-diameter valve recess 10 on the side close to the injection port 3, bifurcated branch guide grooves 37 and 38 are led out. As the distance from the injection port 3 increases, the depths of the branch guide grooves 37 and 38 also become gradually smaller. The two branch guide grooves 37 and 38 are tangentially connected to the large-diameter valve recess 8 and the small-diameter valve recess 11 on the side remote from the injection port 3 respectively. The width of the diversion guide groove 38 connected to the large-diameter valve recess 8 is larger than the width of the diversion guide groove 37 connected to the small-diameter valve recess 11.
The flow rate of the combustion expansion gas into the small-diameter valve recess 11 is made larger than the flow rate of the combustion expansion gas into the small-diameter valve recess 11.
In this embodiment, the swirl centers 41 and 42 of the left and right side jets 22 and 23 are also located at the recess centers 18 of the valve recesses 10 and 7.
-It is located at a position substantially coincident with or at a position in the vicinity thereof. The vortex centers 39 and 40 of the vortex in the valve recesses 8 and 11 substantially coincide with the recess centers 16 and 19.

Although the contents of the embodiments of the present invention are as described above, the present invention is not limited to the above embodiments.
For example, in each of the embodiments, the auxiliary combustion chamber 2 is described as being of the swirl chamber type, but may be of the pre-combustion chamber type. Further, in each of the embodiments, the valve recess is formed on one of the piston head surface 4 and the cylinder head surface 5.
A valve recess may be formed on both the piston head surface 4 and the cylinder head surface 5.

[Brief description of the drawings]

FIG. 1 is a view for explaining a sub-chamber type 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 inside a cylinder, and FIG. FIG.
1A is a cross-sectional view taken along the line BB, and FIG.
FIG. 4 is a sectional view taken along line C of FIG.

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

FIG. 3 is a view showing a sub-chamber type combustion chamber according to a second embodiment of the present invention;
(C) It is an equivalent figure.

FIG. 4 is a view for explaining a sub-chamber type combustion chamber according to Embodiment 3 of the present invention. FIG. 4 (A) is a plan view of a piston head used in the sub-chamber type combustion chamber, and FIG. 4 (A) is a sectional view taken along line BB, FIG. 4 (C) is a sectional view taken along line CC in FIG. 4 (A), and FIG. 4 (D) is a sectional view taken along line DD in FIG. 4 (A). is there.

FIG. 5 is a plan view of a piston head used in a sub-chamber type combustion chamber of a diesel engine according to the related art.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Main combustion chamber, 2 ... Sub combustion chamber, 3 ... Injection port, 4 ... Piston head surface, 5 ... Cylinder head surface, 7.8 ... Large diameter valve recess, 10/11 ... Small valve recess, 12 ... Main injection port, 13・ 14 ・ ・ ・ Left and right side spout, 15 ・ 16 ・ ・ ・ Center of 7.8 recess, 17 ・ ・ ・ Large-diameter recess connection axis, 18 ・ 19 ・ ・ ・ 1
Recess center at 0.11, 11 ... 20 ... connection axis of small diameter recess, 3
2 ... intake valve, 33 ... exhaust valve.

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Manabu Miyazaki 64 Ishizukitamachi, Sakai City, Osaka Prefecture Kubota Sakai Works Co., Ltd. (56) References JP-A-4-339129 (JP, A) JP-A-4-116223 ( JP, A) JP-A 63-71417 (JP, U) JP-A 2-64720 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) F02B 1/00-23/10

Claims (1)

(57) [Claims] An injection hole is provided between a main combustion chamber (1) and a sub-combustion chamber (2).
(3) in communication, at least one of the piston head surface which faces to the main combustion chamber (1) and (4) cylinder head surface (5),
Two large-diameter valve valves corresponding to two large-diameter intake valves (32)
Seth (7) and (8) are recessed, and two small exhaust
Two small diameter valve recesses (10) and (11) corresponding to the valve (33)
Recessed, and the injection port (3) is ejected from the combustion expanding gas is above
Serial large-diameter valve recesses (7), (8) and the small-diameter valve recess
(10) is configured so as to be directed in the (11), 4 valves in the sub-chamber type combustion chamber of a diesel engine, the left and right side injection port provided above jetting nozzle and (3) and on the left and right both sides the main nozzle holes (12) ( 13) - (14) and de-configured, in the main combustion chamber (1) in, among positions in the left <br/> right sides with respect to the jetting nozzle (3), said two of the sides of one large diameter valve recesses provided (7) - (8), said two small-diameter valve recesses (10), (11) provided on the other side of each of the two large-diameter valve recesses (7), (8) Recess center
Large diameter recess connecting axis (17) connecting (15) and (16) and the above two
Center of each of the small diameter valve recesses (10) and (11)
Small diameter recess connecting axis connecting the 9) and (20), but so as to be widened in the form of a slanted roof toward the nozzle hole (3), the large-diameter valve recesses (7), (8) and the small-diameter valve recess (10) - (11) and disposed, the large-diameter valve recesses (7), (8) side of the diameter of the side nozzle holes (14), the small-diameter valve recesses (10), (11) side of the side injection port ( 13) A sub-chamber type combustion chamber for a four-valve diesel engine, which is larger than the diameter of 13).