JP2001152858A - Swirl chamber type combustion chamber for diesel engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve combustion, by generating swirl flow in every corner, in a swirl chamber. SOLUTION: A main combustion chamber 2 is communicated with a swirl chamber 5 by a nozzle hole 6. The nozzle hole 6 is constituted of a single main nozzle hole 7 and a plurality of sub-nozzle holes 8, 8 arranged along the main nozzle hole 7. Air flow A flows from the main combustion chamber 2 into the swirl chamber 5 via the nozzle hole 6 to generate the swirl flow 11 swirling along an inner face of the swirl chamber 5. Each of the sub-nozzle holes 8, 8, arranged along outermost right and left sides of the main nozzle hole 7, is curved into a shape of right and left hyperbolic curves with respect to the center axis 27 of the main nozzle hole 7.

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 technique for improving a combustion by generating a swirling swirl flow to every corner of the swirl chamber.

[0002]

2. Description of the Related Art As a prior art of a swirl type combustion chamber of a diesel engine, for example, there is one shown in FIG. Here, FIG. 5 shows a vortex combustion chamber according to a conventional example, and FIG.
5A is a longitudinal sectional view of a nozzle hole constituting the lower half of the vortex chamber, FIG. 5B is an enlarged vertical sectional view of a main part of the nozzle hole nozzle, and FIG. 5C is a perspective view of the nozzle hole. FIG. 5D is a schematic view of the nozzle hole when the nozzle hole is viewed from below in the direction of the central axis, FIG. 5E is a bottom view of the nozzle hole when the nozzle hole is viewed from below, and FIG. 5) is a vertical front view of the vortex chamber, and FIG. 5 (G) is a vertical side view of the vortex combustion chamber.

This conventional example is configured as follows.
That is, as shown in FIGS. 5F and 5G, the main combustion chamber 102
The swirl chamber 105 is communicated with the swirl chamber 105 through the injection hole 106, and the swirling swirl flow 111 swirling along the inner surface of the swirl chamber 105 is generated by the airflow flowing from the main combustion chamber 102 into the swirl chamber 105 via the injection hole 106. It is configured to be. The vortex chamber 105 is provided at a position greatly deviated from the cylinder center axis 126.

As shown in FIGS. 5A to 5E, a single main injection hole 107 and two sub injection holes 108 are provided.
The sub injection holes 108 are arranged along both sides of the main injection hole 107 over the entire length thereof. As shown in FIG. 5 (F), the swirling vortex 111 includes a main vortex 114 generated in the main injection hole 107 in the compression stroke,
The main vortex 114 is swirled along the inner wall of the central portion of the vortex chamber 105, and the sub vortex 115 is formed along both sides of the main vortex 114. Turn.

According to the above prior art, the fuel injection nozzle 1
The fuel 113 injected from 04 is mixed well with the air by the swirling vortex flow 111, and a considerably good combustion performance can be obtained.
There is room for improvement in the following points. That is, stagnant areas of the swirling vortex flow are recognized on both sides of the sub-vortex flow 115 swirling along both sides of the main vortex flow 114. This is the main vortex 114
It is considered that the flow velocity of the sub-vortex 115 is slow and the spread of the sub-vortex 115 to both sides is small.

[0006]

In order to adapt to the stricter regulation of exhaust gas, vortex flow efficiency is increased by eliminating swirling vortex flow stagnation areas on the left and right sides of the sub-vortex flow, thereby improving combustion efficiency. Therefore, it is necessary to eliminate blue and white smoke, reduce harmful substances in exhaust gas, reduce knocking, improve ignitability, and the like. The present invention has been made in view of such circumstances, and a technical problem of the present invention is to eliminate vortex stagnation areas on both left and right sides of a sub vortex flow, and to circulate vortex flow to every corner of a vortex room. The present invention provides a swirl-type combustion chamber of a diesel engine that can improve combustion by generating the combustion.

[0007]

The present invention is configured as follows to solve the above-mentioned problems. According to the first aspect of the present invention, the main combustion chamber 2 and the swirl chamber 5 communicate with each other through the injection hole 6,
The injection hole 6 is composed of a single main injection hole 7 and a plurality of sub injection holes 8.8 arranged along the main injection hole 7, and the eddy chamber passes through the injection hole 6 from the main combustion chamber 2. The swirling vortex 1 swirling along the inner surface of the vortex chamber 5 due to the airflow A flowing into the vortex 5
In the swirl chamber type combustion chamber of the diesel engine configured to generate the main injection holes 1, the sub injection holes 8 arranged along the left and right outermost sides of the main injection holes 7 It is characterized in that it is formed so as to be curved to the left and right with respect to the central axis 27. Here, “left and right” means the swirling vortex flow 1
1 means the left and right of the traveling direction (hereinafter the same).

According to a second aspect of the present invention, in the swirl-type combustion chamber of the diesel engine according to the first aspect, the swirling vortex flow 11 is applied to the inner surface Sb of the swirl chamber 5 near the injection hole. It is characterized in that a bulging portion 10 that diverges to both sides is formed.

[0009]

According to the first aspect of the present invention, the sub injection holes 8.8 arranged along the left and right outermost sides of the main injection hole 7 are connected to the main injection hole 7. The secondary eddy current 15 is formed by being curved to the left and right hyperbolic shape with respect to the central axis 27.
Are drawn into the main vortex flow 14 and swirl along both sides thereof, while most of the other sub-injections are curved to the left and right with respect to the central axis 27 of the main injection hole 7. The swirling vortex flow spreads right and left by 8.8 and reaches every corner in the vortex chamber 5. That is, even if the flow velocity of the sub-eddy current is low, the stagnation area of the swirling eddy current does not occur on both sides thereof.

(B) According to the invention described in claim 2, FIG.
(A) As shown in (B), the swirling vortex 11 is formed on the inner surface Sb of the vortex chamber 5 near the injection hole, and the swollen vortex 11 is diverted to the left and right sides of the injection hole 6. 11
Is diverted to the left and right before the injection hole 6 by the bulging portion 10, and collision with the strong airflow A flowing from the injection hole 6 is avoided. Thereby, the stagnation area of the swirling vortex flow 11 before the injection hole 6 does not occur.

(C) According to the second aspect of the present invention,
As shown in FIG. 2 (B), the vortices 14a and 14b that have diverted to the left and right before the injection hole 6 are not decelerated.
Flows smoothly along both sides of the airflow A that has flowed in from above, and reinforces the secondary eddy flows 15 on both sides. As a result, the intensity balance of the sub-vortex flows 15 and 15 with respect to the central main vortex flow 14 is equalized, and the mixing of fuel and air in the vortex chamber 5 is further improved as compared with the conventional example, and combustion is remarkable. Be improved. Therefore, eddy current efficiency is increased, and it is possible to improve combustion efficiency, eliminate blue and white smoke, reduce harmful substances in exhaust gas, reduce knocking, improve ignitability, and the like.

[0012]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 shows a vortex combustion chamber according to a first embodiment of the present invention. FIG. 1 (A) is a longitudinal sectional view of a main part of the combustion chamber, and FIG. 1 (B) is a view in FIG. B
FIG. 1 (C) is a perspective view of an injection hole, and FIG.
(D) is a bottom view of the injection hole when the injection hole die is viewed from below.

The vortex combustion chamber has the same basic configuration as that of the conventional example. That is, the main combustion chamber 2 communicates with the lower half of the swirl chamber 5 through the injection hole 6, and the airflow A flowing into the swirl chamber 5 from the main combustion chamber 2 through the injection hole 6 causes the spherical swirl chamber 5 to flow. Is configured to generate a swirling vortex flow 11 that swirls along the inner surface of the vortex. The eddy chamber 5 is provided inside the wall portion 22 of the cylinder head 3 as shown in FIG.
It is greatly deviated from the cylinder center axis 26. Also,
A fuel injection nozzle 4 faces the upper half of the vortex chamber 5.

The lower half of the vortex chamber 5 is formed in a nozzle hole base 24. The nozzle hole base 24 is formed in a recess 23 formed in the lower half of the cylinder wall 3 in the wall 22. It is inserted from the side. The vortex chamber 5 is defined by a hemispherical upper half inner surface Sa and a hemispherical lower half inner surface Sb formed in the injection hole nozzle 24. The injection hole 6 is opened to the injection hole base 24, and its central axis 27 is inclined toward the center of the main combustion chamber 2. The inclination angle θ between the center axis 27 and the bottom surface H of the injection hole base 24 (the end surface of the main combustion chamber 2 on the injection hole side) is set in a range of 40 ° to 50 °,
At 45 °, the strongest swirling vortex flow 11 is generated. As shown in FIGS. 1 (C) and 1 (D), the injection hole 6 is composed of a single main injection hole 7 and two sub injection holes 8, and each sub injection hole 8 has the entire length of the main injection hole 7. Are arranged along both sides.

As shown in FIG. 1C, the main injection hole 7 is formed in a cylindrical shape, and each sub injection hole 8 is formed such that the inner diameter gradually decreases as its peripheral surface approaches the vortex chamber 5. ,
The passage cross-sectional area of the injection hole 6 is configured to gradually decrease as approaching the swirl chamber 5. According to the above configuration, as shown in FIG. 1 (A), the strong air flow A flowing from the main combustion chamber 2 through the injection holes 6 into the swirl chamber 5 in the compression stroke causes
A swirling vortex 11 that swirls along the inner surface of the vortex chamber 5 is formed. The swirling vortex flow 11 is composed of the main vortex flow 14 generated at the main injection hole 7 and the sub vortex flow 15 generated at the sub injection hole 8 as described above.
Swirl along the inner wall of the central vortex, and the sub-vortex 15 swirls along both sides of the main vortex 14.

In this embodiment, the following characteristic configuration is employed in order to improve combustion. That is, FIG.
As shown in (D), each sub injection hole 8.8 arranged along both the left and right sides of the main injection hole 7 is curved in a right and left hyperbolic shape with respect to the central axis 27 of the main injection hole 7. Is formed. This means that a part 15 of the sub-vortex is drawn into the main vortex 14 and swirls along both sides thereof, while the other part 16 is hyperboloidal with respect to the central axis 27 of the main injection hole 7. It is intended that the swirling vortex flow spreads right and left by each of the curved sub-injection holes 8 and 8 to every corner in the swirl chamber 5. Thereby, even if the flow velocity of the sub-eddy current 15 is low, the generation of the eddy current stagnant area on both sides thereof is eliminated.

FIG. 2 shows a vortex combustion chamber according to a second embodiment of the present invention. FIG. 2 (A) is a longitudinal sectional view of a main part of the combustion chamber, and FIG. FIG. 2 (C) is a bottom view of the nozzle hole when the nozzle hole die is viewed from below. In this embodiment, in addition to the sub-injection holes 8.8 curved in a right and left hyperbolic shape, as shown in FIGS. 2A and 2B, the inner surface (lower half portion) of the vortex chamber 5 near the injection holes. Inner surface) S
A bulging portion 10 is formed in b to diverge the swirling main vortex flow 14 to the left and right sides of the injection hole 6.

This is because the swollen portion 10 formed in front of the injection hole 6 (on the upper side in the swirling direction) causes the main swirl 1 to swirl.
The main vortex 14 is divided into the injection holes 6
Of the swirling vortex 11 before the injection hole 6 is prevented, and the bulging portion 10 reduces the dead space in the vortex chamber 5 as much as possible. It is intended to ensure an efficient volume ratio while increasing the compression ratio by making it smaller.

As shown in FIG. 2 (B), the bulging portion 7 is formed symmetrically with a gentle convex curved surface having its vertex in front of the injection hole 6, and its skirt portion is formed in the eddy chamber 2 Is formed so as to be smoothly continuous with the inner surface Sb of the substrate. This reduces the flow resistance of the bulging portion 10 to the main vortex flow 14 and prevents the generation of unnecessary turbulence when the main vortex flow 14 is divided right and left before the injection hole 6. It is intended.

That is, the main vortex flow 14a divided into right and left
14b smoothly flows along both sides of the airflow A flowing from the injection hole 6 without being decelerated, and the sub-vortex flows 15 on both the left and right sides.
・ Reinforce 15 As a result, the intensity balance between the side vortex streams 15 and 15 on both sides with respect to the central main vortex stream 14 is further equalized, the mixing of fuel and air in the vortex chamber 5 is further improved, and the combustion is significantly improved. You. Therefore, eddy current efficiency is increased, and it is possible to improve combustion efficiency, eliminate blue and white smoke, reduce harmful substances in exhaust gas, reduce knocking, improve ignitability, and the like.

Generally, the swirl chamber 5 is a plus element in that the swirling vortex contributes to the improvement of combustion, and a minus element in increasing the compression ratio of the diesel engine. It greatly reduces the dead space inside and increases the compression ratio, and contributes to securing an efficient volume ratio.

FIG. 3 shows a third embodiment of the present invention. FIG. 3 (A) is a longitudinal sectional view of a main part of a vortex chamber, and FIG. 2 (B) is a vertical sectional front view of a main part of the vortex chamber. 2 (C) is a perspective view of the injection hole,
FIG. 2D is a bottom view of the injection hole when the injection hole die is viewed from below. In this embodiment, similarly to the second embodiment, a bulging portion 10 is formed on the inner surface Sb of the lower half portion of the vortex chamber 5 to divide the main vortex flow 14 into the left and right sides of the injection hole 6, and FIG. C)
As shown in (D), two sets of sub injection holes 8a and 8b are arranged along the left and right sides of the main injection hole 7, respectively.

The pair of sub injection holes 8a arranged on both inner sides
8a has its axis line as shown in FIGS.
The pair of sub-injection holes 8b, 8b, which are formed so as to intersect at the rearward crossing portion K in the front-rear direction at the middle part in the vertical direction and the left-right direction in the vortex chamber 5, and are arranged on both outer sides, are the main injection holes 7b. Are formed so as to be curved to the left and right with respect to the central axis 27 of the right side.

This is because the sub-eddy currents 15 generated by the inner sub-injections 8a collide at the intersection K, and the sub-eddy jets 8b generated by the outer sub-injections 8b are formed. The vortex flows 16 and 16 are intended to spread to the left and right of the sub-vortex flows 15 and 15 so that the swirling vortex flows to every corner in the vortex chamber 5. Also in this embodiment, the main vortex 14a · 1 diverted right and left by the bulging portion 10 is also used.
4b reinforces the sub-vortex 15 on both sides of the inner side, eliminates the occurrence of a stagnation area of the swirling vortex 11 in front of the injection hole 6, and the stagnation area on both sides of the sub-vortex 15 Eliminate what happens.

FIG. 4 is a sectional view of a main part of a swirl type combustion chamber according to a fourth embodiment of the present invention. This is one in which the vortex combustion chamber according to the second embodiment is applied to a horizontal diesel engine. That is, in this embodiment, the main combustion chamber 2 and the swirl chamber 5 communicate with each other through the injection hole 6, and the airflow A flowing into the swirl chamber 5 from the main combustion chamber 2 via the injection hole 6 causes the spherical swirl chamber to be formed. 5 is configured to generate a swirling vortex flow 11 that swirls along the inner surface of the swirl 5. Each of the sub-injection holes 8.8 arranged along the left and right sides of the main injection hole 7 is formed so as to be curved to the left and right with respect to the central axis 27 of the main injection hole 7. Furthermore, the inner surface (inner surface near the injection hole) Sb of the injection hole mouthpiece 24
Also, a bulging portion 10 is formed which divides the main vortex 14 to the left and right sides of the injection hole 6.

According to the fourth embodiment, the swelling portion 10 reduces the fuel pool generated in the lower portion of the swirl chamber 5 and eliminates an ignition error during cold start or cold start. That is, in the horizontal diesel engine, the fuel injected from the injector 4 tends to accumulate in the lower part of the swirl chamber 5 at the time of cold or cold start, and misfire may cause blue-white smoke or poor combustion. However, according to the fourth embodiment, the bulging portion 10 is provided on the inner surface (inner surface near the injection hole) Sb of the injection hole mouthpiece 24.
By forming the above, the above inconvenience can be solved.

Although the contents of the swirl type combustion chamber according to the embodiment of the present invention are as described above, the contents of the present invention are not limited to the above embodiment. That is, in the third embodiment, a pair of sub injection holes 8a, 8a
Are formed so that their axes intersect with each other, but at least the sub injection holes 8b
May be curved to the left and right in a hyperbolic shape with respect to the center axis 27 of the sub-injection holes 8a.
Changes can be made as appropriate.

The swollen portion 10 for diverting the swirling swirl flow 11 to the left and right sides of the injection hole 6 may be formed on the inner surface of the swirl chamber 5 near the injection hole. The present invention is not limited to this, and may be formed over the upper half inner surface Sa and the lower half inner surface Sb forming the swirl chamber 5. Further, the shape of the bulging portion 10 is not limited to the illustrated one.
The shape may be widened toward the injection hole 6.

Further, the main injection hole 7 is formed in an elliptical column shape, a square column shape,
Or a triangular prism shape, or a different opening shape between the swirl chamber 5 side and the main combustion chamber 2 side, a tapered shape in which the main injection hole 7 is reduced toward the swirl chamber 5,
The sub injection hole 8 may have a columnar shape, an elliptical columnar shape, or a rectangular columnar shape.

[Brief description of the drawings]

FIG. 1 shows a vortex combustion chamber according to a first embodiment of the present invention. FIG. 1 (A) is a longitudinal sectional view of a main part of the vortex combustion chamber, and FIG. 1 (B) is FIG. 1A is a vertical sectional view taken along the line BB in FIG. 1A, FIG. 1C is a perspective view of the nozzle hole, and FIG. 1D is a bottom view of the nozzle hole when the nozzle hole base is viewed from below.

FIG. 2 shows a swirl type combustion chamber according to a second embodiment of the present invention. FIG. 1 (A) is a longitudinal sectional view of a main part of the swirl type combustion chamber, and FIG. 1 (B) is an injection hole base. 1 (C) is a bottom view of the nozzle hole when the nozzle hole die is viewed from below.

FIG. 3 shows an eddy chamber according to a third embodiment of the present invention,
3A is a vertical sectional view of the swirl chamber, FIG. 3B is a vertical front view of the swirl chamber, FIG. 3C is a perspective view of the injection hole, and FIG.
(D) is a bottom view of the injection hole when the injection hole die is viewed from below.

FIG. 4 is a sectional view of a main part of a swirl type combustion chamber according to a fourth embodiment of the present invention.

FIG. 5 shows a vortex combustion chamber according to the prior art;
5A is a longitudinal sectional view of the nozzle hole nozzle, FIG. 5B is an enlarged vertical sectional view of a main part of the nozzle hole nozzle, FIG. 5C is a perspective view of the nozzle hole, and FIG. FIG. 5 (E) is a bottom view of the injection hole when the nozzle is viewed from below, and FIG. 5 (F) is a vertical front view of the eddy chamber. FIG.
(G) is a vertical side view of the vortex combustion chamber.

[Explanation of symbols]

2: Main combustion chamber, 5: swirl chamber, 6: injection hole, 7: main injection hole, 8
· 8a · 8b ··· sub-injection hole, 10 ··· bulging part, 11 · · · swirling vortex flow, 14 · · · main vortex flow, 27 · · · central axis of main injection hole, A · air flow, Sa · Sb · inner surface of vortex chamber, Sb ... Inner side (inner side of nozzle hole).

Claims (2)

[Claims] The main combustion chamber (2) and the swirl chamber (5) communicate with each other through an injection hole (6), and the injection hole (6) is connected to a single main injection hole (7).
And a plurality of sub-injection holes (8.8) arranged along the main injection hole (7), and from the main combustion chamber (2) through the injection hole (6) in the swirl chamber (5). In the swirl type combustion chamber of the diesel engine configured to generate the swirling swirl (11) swirling along the inner surface of the swirl chamber (5) by the air flow (A) flowing into the swirl chamber (5), the main injection hole ( 7) Each sub injection hole (8.8) arranged along the left and right outermost sides is curved in a right and left hyperbolic shape with respect to the center axis (27) of the main injection hole 7; A swirl chamber combustion chamber for a diesel engine. 2. The swirl-type combustion chamber of a diesel engine according to claim 1, wherein the swirling vortex flow (11) is applied to an inner surface (Sb) of the swirl chamber (5) near the injection hole. A swirl-type combustion chamber for a diesel engine, wherein a swollen portion (10) diverging to both left and right sides is formed.