JP2000179343A - Diesel engine swirl chamber - Google Patents

Abstract

(57) Abstract: In a swirl chamber type combustion chamber of a diesel engine, a swirl chamber (2) includes a raised portion (7), and the raised portion (7) is a hemispherical surface of an inner surface (8) of the swirl chamber (2) on a communication hole (4) side. 9, the upper end face 7 a of the raised portion 7 is formed along the upper portion of the swirling direction of the swirl 18 from the communication hole 4, and the upper end surface 7 a of the raised portion 7 communicates when viewed in a direction parallel to the cylinder center axis 10. The hole 4 is disposed at a position that does not overlap with the vortex chamber side opening 11. [Effect] When a part of the vortex 18 touches the end face 7a of the raised portion 7, a minute turbulence is formed inside and outside the vortex 18, and the mixing of the injected fuel 15 and the air in the vortex chamber 2 is improved. Become. For this reason, a combustion period is shortened, the emission amount of particulate matter is reduced, and smoke is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a swirl type combustion chamber for a diesel engine, and more particularly to a combustion chamber capable of improving combustion performance.

[0002]

2. Description of the Related Art Conventionally, as a swirl chamber type combustion chamber of a diesel engine, a main combustion chamber, a swirl chamber, a fuel injection nozzle, and a communication hole are provided. The main combustion chamber is provided in a cylinder, and the swirl chamber is a cylinder. In some heads, the fuel injection nozzle faces the swirl chamber and connects the main combustion chamber and the swirl chamber through the communication hole.

In this conventional combustion chamber, the inner surface of the swirl chamber has a spherical shape without irregularities.

[0004]

In the above prior art, the inner surface of the eddy chamber has a spherical shape without irregularities, and it is impossible to give a change to the eddy flow with this shape as it is. Therefore, even if the volume of the swirl chamber is adjusted or the injection timing is adjusted, there is a limit to the improvement of the combustion performance.

[0005] It is an object of the present invention to provide a swirl-type combustion chamber of a diesel engine capable of improving combustion performance by changing a swirl flow.

[0006]

The structure of the first aspect of the present invention is as follows. As shown in each figure (A), the main combustion chamber
(1) a swirl chamber (2), a fuel injection nozzle (3), and a communication hole (4), the main combustion chamber (1) is provided in a cylinder (5), and the swirl chamber (2) is The fuel injection nozzle (3) is provided in a cylinder head (6) and faces the vortex chamber (2).
In the swirl chamber type combustion chamber of a diesel engine, which is configured to communicate the main combustion chamber (1) and the swirl chamber (2) with the communication hole (4), the following is performed. .

[0007] As shown in each figure (A), the eddy chamber (2) is provided with a raised portion (7), and the raised portion (7) is provided in the eddy chamber (2).
The inner surface (8) of the hemisphere (9) on the side of the communication hole (4) is formed along a portion on the upstream side in the swirling direction (18) in the swirling direction from the communication hole (4), and The upper end surface (7a) of the portion (7) is disposed at a position that does not overlap with the vortex chamber side opening (11) of the communication hole (4) when viewed in a direction parallel to the cylinder center axis (10). It is characterized by having been done.

[0008]

Operation and Effect of the Invention (Invention of claim 1) The invention of claim 1 has the following operation and effects. As shown in each figure (A),
When a part of the vortex (18) touches the end surface (7a) of the bulge (7), a minute turbulence is formed inside and outside the vortex (18), and the injected fuel (15) in the vortex chamber (2) is formed. ) And air are better mixed. For this reason, a combustion period is shortened, the emission amount of particulate matter is reduced, and smoke is reduced.

(Invention of claim 2) The invention of claim 2 has the following operation and effect in addition to the operation and effect of the invention of claim 1.
As shown in each figure (C), the communication hole (4) is the main communication hole (1).
2) and sub-communication holes (13) and (13).
3) (13) extends along the peripheral surface over the entire length of the main communication hole (12), and the main communication hole (12) and the sub communication hole (13)
Since the boundary with (13) is formed by the ridges (14) and (14) that protrude sharply toward the main communication hole (12), there are the following advantages. As shown in each figure (A), a ridge is formed by a pushing flow (19) passing through the communication hole (4) toward the vortex chamber (2).
Since a small turbulent flow is formed near the swirl chamber side end of (14), the mixing of the injected fuel (15) and air in the swirl chamber (18) is further improved.

(Invention of claim 3) The invention of claim 3 has the following operation and effect in addition to the operation and effect of the invention of claim 1 or 2. As shown in each figure (A), the fuel injection nozzle
(3) has the following advantages because the injected fuel (15) is directed toward the swirl chamber side opening (11) of the communication hole (4). As shown in each figure (A), the injected fuel (15) collides with the pushing flow (19) blown out from the communication hole (4) and is scattered in the swirl chamber (2). Injection fuel
Mixing of (15) with air is further improved.

(Invention of claim 4) The invention of claim 4 has the following operation and effect in addition to the operation and effect of any one of the inventions of claims 1 to 3. As shown in FIGS. 1 (B) and 4 (B), the end face (7a) of the raised portion (7) is aligned with the cylinder center axis (1).
When viewed in a direction parallel to 0), it has a crescent shape along the inner surface (8) of the vortex chamber (2), and has the following advantages. End face
Since the (7a) can be formed thin and long, the contact area of the eddy flow (18) to the end face (7a) is largely secured without reducing the flow velocity of the eddy flow (18) so much that the minute turbulence Can be generated efficiently, and the mixing of the injected fuel (15) and air in the swirl chamber (2) is further improved.

(Invention of claim 5) The invention of claim 5 has the following effects in addition to the effects of the inventions of claims 1 to 4. As shown in FIGS. 3A and 3B, the raised portion (7) has a guide groove (16), and the guide groove (16) is provided with the communication hole.
Since it is continuous with (4), there are the following advantages. As shown in FIG. 3A, the vortex (1) guided by the guide groove (16) is used.
Push-in flow (19) in which part of 8) gushes from communication hole (4)
And the turbulence inside and outside the vortex flow (18) diffuses throughout the vortex chamber (2), so that the mixing of the injected fuel (15) and air in the vortex chamber (2) is further improved.

(Invention of claim 6) The invention of claim 6 has the following operation and effect in addition to the operation and effect of any one of the inventions of claims 1 to 5. As shown in FIG. 4, the communication hole (4) is provided with a deflecting groove (17), and the deflecting groove (17) is directed to the upstream side of the eddy flow (18). FIG.
As shown in (A), a part of the pushing flow (19) guided by the deflection groove (17) collides with the eddy flow (18), and a new turbulent flow is generated. The mixing of the injected fuel (15) with the air at the step is even better.

[0014]

Embodiments of the present invention will be described with reference to the drawings. 1 to 4 are diagrams illustrating a swirl type combustion chamber of a diesel engine according to each embodiment of the present invention.

The configuration of the first embodiment shown in FIG. 1 is as follows. As shown in FIG. 1A, the swirl chamber combustion chamber includes a main combustion chamber (1), a swirl chamber (2), a fuel injection nozzle (3), and a communication hole (4). The combustion in the swirl chamber combustion chamber is performed as follows. In the compression stroke, the main combustion chamber
The air in (1) becomes a forced flow (19) and becomes a communication hole (4).
And this becomes eddy current (18) in the eddy chamber (2),
The injected fuel (15) and the air are mixed in the swirl chamber (2).
This mixture is ignited by the heat of compression in the vortex chamber (2),
(23) blows out to the main combustion chamber (1). And the inflation gas
(23) and the air in the main combustion chamber (1) are mixed, and this air-fuel mixture is ignited by the compression heat in the main combustion chamber (1) and burns.

The main combustion chamber (1) is formed between the piston (20) fitted inside the cylinder (5) and the cylinder head (6), and is located in the cylinder (5). The vortex chamber (2) is formed by aligning the hemispherical inner end surface of the recess (21) of the cylinder head (6) with the hemispherical inner surface of the base (22) press-fitted into the recess (21). And is formed in a spherical shape. This eddy room (2)
Is formed in a true spherical shape, but may be in an elliptical shape. The vortex chamber (2) is formed in the cylinder head (6) at a position deviated from the cylinder center axis (10). The combustion injection nozzle (3) is attached to the cylinder head (6) and faces the swirl chamber (2), through which the injection fuel (15) communicates.
(12) is directed toward the vortex chamber side opening (11).

The communication hole (4) is formed in the base (22) and includes a main communication hole (12) and a pair of sub communication holes (13) and (13).
Each of the sub communication holes (13) (13) extends along the peripheral surface over the entire length of the main communication hole (12). The main communication hole (12) is formed in a cylindrical shape, and the sub communication hole (13) is formed in a truncated cone shape whose diameter decreases toward the vortex chamber (2). The main communication hole (12) is oriented from the swirl chamber (2) toward the center of the main combustion chamber (1). As shown in FIG. 1 (C), each of the sub-communication holes (13) and (13) has a main communication hole (1) when viewed in a direction parallel to the cylinder center axis (10).
It is located on both sides of 2), and is oriented in such a direction as to expand in both sides of the main communication hole (12) from the swirl chamber (2) to the main combustion chamber (1). Main communication hole (12) and sub communication hole (13) (13)
Are formed by ridges (14) (14) that protrude sharply toward the main communication hole (12).

The vortex chamber (2) has a raised portion (7). The raised portion (7) is configured by raising a part of the inner surface of the base (22). This ridge (7) is the inner surface of the vortex chamber (2).
The vortex (18) of the hemisphere (9) on the side of the communication hole (4) of (8)
It is formed along the upper part in the turning direction. FIG.
As shown in (A), the cross-sectional shape of the raised portion (7) is curved in an arc along the inner surface (8) of the vortex chamber (2) when viewed from a direction perpendicular to the cylinder center axis (10). It has a nail shape. Ridge
The end surface (7a) on the upper side of (7) is the cylinder center axis.
Seeing in a direction parallel to (10), the vortex chamber side opening of the communication hole (4)
The vortex chamber is located so that it does not overlap with (11).
It has a crescent shape along the inner surface (8) of (2).

In the second embodiment shown in FIG. 2, the raised portion (7)
The upper end surface (7a) is formed in a bow shape having a straight chord. In the third embodiment shown in FIG.
The upper end surface (7a) of (7) is formed in an arc shape having a straight chord, and the raised portion (7) has a guide groove (1).
6). The guide groove (16) is formed in a concavely curved surface of the raised portion (7) extending from the end face (7a) to the communication hole (16). The guide groove (16) is continuous with the communication hole (4). In the fourth embodiment shown in FIG. 4, the communication hole (4) has a deflection groove (17), and this deflection groove (17) is directed to the upstream side of the vortex (18). Other structures of the second to fourth embodiments of FIGS. 2 to 4 are the same as those of the first embodiment of FIG. 1. In FIGS. 2 to 4, the same elements as those of FIG. Is attached.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a first embodiment of the present invention.
1A is a longitudinal sectional view of a combustion chamber, FIG. 1B is a plan view of a base, and FIG. 1C is a schematic view of a communication hole as viewed from a direction C in FIG. 1A.

FIG. 2 is a diagram for explaining a second embodiment of the present invention.
2A is a longitudinal sectional view of a combustion chamber, FIG. 2B is a plan view of a base, and FIG. 2C is a schematic view of a communication hole viewed from a direction C in FIG. 2A.

FIG. 3 is a diagram for explaining a third embodiment of the present invention.
3A is a longitudinal sectional view of a combustion chamber, FIG. 3B is a plan view of a base, and FIG. 3C is a schematic diagram of a communication hole viewed from a direction C in FIG. 3A.

FIG. 4 is a diagram for explaining a fourth embodiment of the present invention.
4A is a longitudinal sectional view of a combustion chamber, FIG. 4B is a plan view of a base, and FIG. 4C is a schematic view of a communication hole viewed from a direction C in FIG. 4A.

[Explanation of symbols]

(1) ... main combustion chamber, (2) vortex chamber, (3) ... fuel injection nozzle, (4) ... communication hole, (5) ... cylinder, (6) ... cylinder head, (7) ... bulge, (7a) ... end face, (8) ... inner face, (9)
... hemispherical surface, (10) central axis of cylinder, (11) vortex chamber side opening, (12) main communication hole, (13) sub communication hole, (14)
... ridge, (15) ... injected fuel, (16) ... guide groove, (17) ...
Deflection grooves, (18) ... vortex.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Setsuo Yamada 3-8 Chikushinmachi, Sakai City, Osaka Inside Kubota Sakai Rinkai Plant (72) Inventor Shunichi Manwa 3-8 Chikushinmachi, Sakai City, Osaka Prefecture Inside the Kubota Sakai Rinkai Plant (72) Keita Naito 3-8 Chikushinmachi, Sakai City, Osaka Prefecture Inside the Kubota Sakai Coastal Plant (72) Yoshihiko Fujiwara 3-8 Chikushinmachi, Sakai City, Osaka 3G023 AA04 AA07 AB05 AC05 AD09 AD22 AD23 AD27

Claims (6)

[Claims] 1. A main combustion chamber (1), a swirl chamber (2), a fuel injection nozzle (3), and a communication hole (4). The main combustion chamber (1) is provided in a cylinder (5). The swirl chamber (2) is provided in the cylinder head (6), the fuel injection nozzle (3) faces the swirl chamber (2), and the main combustion chamber (1) is connected to the communication hole (4).
And the swirl chamber (2) communicates with the swirl chamber type combustion chamber of the diesel engine. The swirl chamber (2) has a raised portion (7), and the raised portion (7)
Is a part of the inner surface (8) of the vortex chamber (2) on the side of the communication hole (4) on the side of the communication hole (4), on the upper side in the swirling direction (18) in the swirling direction from the communication hole (4). Formed along the ridge
The end surface (7a) on the upper side of (7) is the cylinder center axis.
A swirl chamber type combustion chamber for a diesel engine, wherein the swirl chamber type combustion chamber of a diesel engine is arranged so as not to overlap with the swirl chamber side opening (11) of the communication hole (4) when viewed in a direction parallel to (10). 2. The swirl-type combustion chamber of a diesel engine according to claim 1, wherein the communication hole (4) is a main communication hole.
(12) and sub-communication holes (13) and (13).
(13) (13) extends along the peripheral surface over the entire length of the main communication hole (12), and the main communication hole (12) and the sub communication hole (1)
3) A swirl chamber type combustion of a diesel engine, characterized in that the boundary with (13) is formed by ridges (14) (14) protruding sharply toward the main communication hole (12). Room. 3. The swirl-type combustion chamber of a diesel engine according to claim 1, wherein the fuel injection nozzle (3) is configured such that the injected fuel (15) is provided in the communication hole (4).
A swirl chamber type combustion chamber for a diesel engine, which is oriented so as to face a swirl chamber side opening (11). 4. The swirl type combustion chamber of a diesel engine according to claim 1, wherein the raised portion is provided.
The end face (7a) of (7) has a crescent shape along the inner surface (8) of the vortex chamber (2) when viewed in a direction parallel to the cylinder center axis (10). Whirlpool combustion chamber for diesel engine. 5. The swirl chamber type combustion chamber of a diesel engine according to claim 1, wherein the raised portion (7) has a guide groove (16), and the guide groove (16) is provided with the guide groove (16). A swirl-type combustion chamber for a diesel engine, which is continuous with the communication hole (4). 6. The swirl chamber type combustion chamber of a diesel engine according to claim 1, wherein the communication hole is provided.
(4) has a deflection groove (17), and this deflection groove (17)
A swirl-type combustion chamber for a diesel engine, which is directed to the upstream side of (18).