JP2603563B2 - Diesel engine swirl chamber - Google Patents

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.

[0002]

BACKGROUND OF THE INVENTION In a swirl chamber type combustion chamber of a diesel engine, an injection port of the swirl chamber is tangentially connected to the swirl chamber, and the main combustion chamber is connected to the swirl chamber via the injection port. Is adopted as a general structure.

In the swirl chamber type combustion chamber having such a structure, unburned gas and burned gas having different masses are separated from each other in the swirl chamber by centrifugal force based on swirling of the swirl flow. aggregate is less burned gas having a mass in the vicinity of, here locally high temperature and become by N0 _X generation is promoted. Therefore, in the swirl chamber type combustion chamber, reducing of the NO _X is one of the important issues.

[0004]

BACKGROUND ART Conventionally, as a technique to reduce the NO _X, is disclosed in Japanese Unexamined Utility Model Publication No. 60-139030. As shown in FIG. 4, a gas discharge device 102 is provided in the vicinity of the center of an eddy chamber 101. According to this, since the burned gas can be prevented from flowing into the vicinity of the center of the swirl chamber 101, the separation of the unburned gas and the burned gas in the swirl chamber 101 can be prevented. it is possible to reduce the generation amount of the NO _X to prevent the high-temperature region by a set of the burnt gas is formed in the chamber 101.

In this prior art, according to the above-mentioned publication, the gas repelling device 102 is provided in the swirl chamber 101, so that the velocity distribution of the swirl flow can be made uniform, thereby making the fuel distribution uniform. It is described that the generation amount of HC / CO can be reduced. FIG.
As shown in (B), particularly by narrowing both end portions of the gas rejection device 102, the combustion gas can be smoothly injected from the swirl chamber 101 to the main combustion chamber. Is described, whereby the output of the engine can be improved and the fuel consumption can be reduced.

[0006] However, this prior art only shows a means for improving eddy currents and combustion gases, and does not show HC / HC.
The following problems arise because there is no devising for the miniaturization and promotion of diffusion of the injected fuel, which are the most important factors for reducing CO, improving the output performance of the engine, and reducing fuel consumption.

[0007]

In the above-mentioned prior art, it is not possible to sufficiently miniaturize and diffuse the injected fuel, so that it is not possible to expect an improvement in the mixing performance of the injected fuel and air. For this reason, the combustion performance cannot be sufficiently improved, and HC
It is not possible to sufficiently reduce CO, improve the output performance of the engine, and reduce the fuel consumption.

The present invention, while at the same time achieve a reduction of NO _X, be achieved by miniaturization and diffusion of promotion of the injected fuel in sufficient improvement of the output performance of the engine, is referred to as its object.

[0009]

Means for Solving the Problems (First Invention) In a first invention, as shown in FIG. 1 (A), an injection port 2 is tangentially connected to a swirl chamber 1 of a diesel engine, and through the injection port 2. The swirl chamber type combustion chamber of a diesel engine in which the swirl chamber 1 communicates with the main combustion chamber 3, the fuel injection nozzle 4 faces the swirl chamber 1, and the column-shaped gas rejection device 5 is provided in the swirl chamber 1. Is characterized by the following.

That is, as shown in FIGS. 1 to 3, the axis 17 of the gas repelling device 5 is aligned with the center axis 18 of the swirl of the vortex flow 10 in the vortex chamber 1, and the injection axis of the injected fuel 7 is adjusted. The core 6 is configured so as to intersect the outer peripheral surface of the gas rejection device 5, and the injected fuel 7 from the fuel injection nozzle 4 is injected near the intersection 8 with the injection axis 6 on the outer peripheral surface of the gas rejection device 5. Crash surface part 9
The gas rejecting device 5 is configured such that it collides with the air outlet 2 on the outer surface of the gas discharge device 5 facing the injection port 2 along the swirling direction of the vortex flow 10. , So that a part 34 of the air pushed into the swirl chamber 1 from the injection port 2 by the press-fit air reversal guide surface 32 is guided in a direction against the swirl flow 10. Is what you do.

(Second Invention) In the second invention, as shown in FIG. 2, the outer peripheral surface of the gas rejection device 5 from the main combustion chamber 3 to the swirl chamber 1 via the injection port 2 as shown in FIG. A passage-enlarging recessed surface 31 is formed in the nozzle-extended-side peripheral surface portion 40 that overlaps with the swirl-chamber extended space 33 of the nozzle 2 through which the pushed air first passes. A press-fit air reversal guide surface 32 is provided adjacent to the upstream side of the turbulent flow 10 and the jetting protruding surface portion 9 is positioned downstream of the turbulent flow 10 from the passage enlarging concave surface 31. It is.

[0012]

Operation (First Invention) The operation of the first invention will be described with reference to FIG.

The fuel 7 injected from the fuel injection nozzle 4 is
By colliding with the jet colliding surface portion 9 of the gas rejecting device 5 and reflecting and scattering, the miniaturization and diffusion of the injected fuel 7 are promoted.

Injection fuel 7 which collides with the injection collision portion 9
However, the vaporization of the injected fuel 7 in the vortex chamber 1 is promoted by absorbing the heat of the gas discharger 5 which has been heated by the combustion flame in the vortex chamber 1 and has a high temperature.

Since the press-in air reversal guide surface 32 is formed by recessing the outer peripheral surface of the gas discharger 5, the cross-sectional area of the vortex 10 at the location where the press-in air reversal guide surface 32 is provided is reduced. It has become wider and the air passage resistance has become smaller. In addition, the press-fit air reversal guide surface 32 actively guides a part 34 of the air pushed in from the nozzle 2 in the direction against the vortex flow 10.
A part 34 of the air pushed in from the above-mentioned nozzle 2 is a vortex 1
The vortex flows quickly to the upstream side of 0, and a small vortex is generated in the vortex flow 10.

(Second Invention) The second invention operates as follows in addition to the operation of the first invention. As shown in FIG. 2 (B), the passage resistance of the air in the swirl chamber extension space 33 is reduced by the passage enlarging concave surface 31, so that the air is forced from the main combustion chamber 3 into the swirl chamber extension space 33. In addition, the cross-sectional area of the vortex flow 10 in the space where the injected fuel 7 scatters, which is downstream of the vortex flow 10 from the passage enlarging concave surface 31, becomes narrow, and the velocity of the vortex flow 10 in that space decreases. Be faster.

[0017]

(First invention) The first invention has the following effects (1) to (4).

A press-fit air reversal guide surface is formed by recessing the outer peripheral surface of the gas rejection device, and the press-fit air reversal guide surface allows a part of the air pushed in from the injection port to be positively directed in a direction against the vortex flow. So that a portion of the air pushed in from the above-mentioned injection port can be quickly flowed to the upstream side of the vortex, and a small vortex is reliably generated in the vortex, and the injected fuel and air Can be further improved. As a result, the reduction of HC and CO, the improvement of the output performance of the engine, and the reduction of fuel consumption can be further ensured.

[0019]

[0020]

(Second Invention) The second invention has the following effects in addition to the effects of the first invention. By forming a passage-enlarging concave surface on the peripheral surface of the gas rejection device on the nozzle extension side, the air passage resistance in the swirl chamber extension space is reduced, and the air from the main combustion chamber to the swirl chamber extension space vigorously In addition to being pushed in, the cross-sectional area of the vortex flow in the space where the injected fuel scatters, which is downstream of the vortex flow from the passage enlarging concave surface, becomes narrow and the vortex flow speed in that space increases. In addition, the mixing performance of the injected fuel and air can be further enhanced, whereby the HC / CO can be reduced, the output performance of the engine can be improved, and the fuel consumption can be further reduced.

[0022]

An embodiment of the present invention will be described with reference to the drawings. (First Embodiment) FIG. 1 is a view for explaining a swirl chamber type combustion chamber according to a first embodiment of the present invention. FIG. 1 (A) is a longitudinal sectional view of the swirl chamber type combustion chamber, and FIG. 1 (B). 1A is a cross-sectional view taken along the line BB of FIG. 1A, FIG. 1C is a perspective view of the gas discharging device used in the first embodiment, and FIG. 1D is a cross-sectional view taken along the line DD of FIG. FIG.

In FIG. 1A, reference numeral 50 indicates a swirl-type combustion chamber of a diesel engine, which is as follows. As shown in FIG. 1A, a piston 13 is fitted into a cylinder 12 of a cylinder block 11, and a main combustion chamber 3 is formed above the piston 13.
Cylinder head 1 assembled on cylinder block 11
The swirl chamber 1 is formed in the inside 4, the upper half of the swirl chamber 1 is formed in the wall of the cylinder head 14, and the lower half of the swirl chamber 1 is formed in the injection nozzle 15 fitted into the cylinder head 14. Is formed. An injection port 2 tangentially communicating with the swirl chamber 1 is formed on the bottom wall of the injection nozzle 15, and the swirl chamber 1 is connected to the main combustion chamber 3 via the injection port 2. A fuel injection nozzle 4 faces the vortex chamber 1.

[0024] In the swirl chamber type combustion chamber 50, to reduce the generation amount of NO _X, as shown in FIG. 1 (A) · (B) , the gas displacing member 5 disposed in the vicinity of the center of the swirl chamber 1 ing. As shown in FIG. 1C, the gas repelling device 5 has a cylindrical shape, and as shown in FIG.
And is suspended along the center axis 18 of the swirling flow 10. The axis 17 of the gas rejection device 5 is a vortex 10
Of the turning center axis 18.

In the swirl chamber combustion chamber 50, as shown in FIG. 1A, the injection axis 6 of the fuel injection nozzle 4 is connected to the gas rejection device 5 in order to promote the miniaturization and diffusion of the injected fuel. In the crossing direction, the injected fuel 7 from the fuel injection nozzle 4 collides with and is reflected by the jet-emergence surface 9 near the intersection 8 with the injection axis 6 on the outer peripheral surface of the gas rejection device 5. It is configured to scatter.

The jetting protruding surface portion 9 uses the peripheral surface of the columnar gas repelling device 5 as it is. For this reason, as shown in FIG. 1 (D), the jetting protruding surface portion 9 has a convex shape along the swirling direction of the vortex flow 10.

In this swirl chamber type combustion chamber 50, FIG.
As shown in (D), the angle θ formed by the injection axis 6 with respect to the injection protruding surface 9 is set to an acute angle on the upstream side of the flow 10 from the injection axis 6 of the fuel injection nozzle 4. Therefore, the injected fuel 7 can be reflected toward the downstream of the vortex flow 10 and the injected fuel 7 can be smoothly involved in the vortex flow 10, whereby the mixing performance of the injected fuel 7 and air can be improved.

Further, since the angle θ formed by the injection axis 6 with respect to the jetting protruding surface portion 9 is set to an acute angle, the injected fuel 7 collides obliquely with the jetting protruding surface portion 9 and the injected fuel 7 becomes The collision area of the injected fuel 7 is increased and the heat received by the injected fuel 7 from the gas rejection device 5 is increased as compared with the case where the collision occurs. Therefore, the vaporization of the injected fuel 7 in the swirl chamber 1 can be promoted. Reference numeral 19 denotes a tangent line of the jetting protruding surface portion 9 at the intersection 8.

In the swirl chamber type combustion chamber 50, in order to improve the mixing performance of the injected fuel and the air, the extension of the orifice that overlaps with the swirl chamber extension space 33 of the orifice 2 in the outer peripheral surface of the gas discharger 5 is provided. As viewed from the side peripheral surface portion 40, the vortex 10
A press-fit air reversal guide surface 32 is formed in an upstream adjacent peripheral surface portion 41 adjacent to the upstream side of the press-fit air reversal guide surface 3.
Numeral 2 is formed so as to guide a part 34 of the air pushed into the vortex chamber 1 from the injection port 2 in a direction against the vortex flow 10.

(Second Embodiment) FIG. 2 is a view for explaining a gas discharging device used in a second embodiment. In the second embodiment,
A passage-enlarging concave surface 31 is formed in the peripheral surface portion 40 on the nozzle port extension side of the gas discharger 5.

(Third Embodiment) FIG. 3 is a diagram for explaining a third embodiment. In the third embodiment, as shown in FIG. 3B, a hollow portion 30 is formed in the gas discharger 5 of the first embodiment.

In the third embodiment, since the inside of the jetting blast surface 9 of the gas discharging device 5 is hollowed by the hollow portion 30, the temperature of the gas discharging device 5 rises quickly. For this reason, quick ignition can be performed even in cold weather, thereby improving warm-up performance.

Although the embodiments of the present invention are as described above, the present invention is not limited to the above embodiments. For example,
The hollow portion 30 added in the third embodiment may be added to the second embodiment.

Further, the gas repelling device 5 is not limited to a pillar shape, but may be a spherical shape or other block shape. In this case, the support may be supported by a support rod or the like protruding from the peripheral wall of the swirl chamber 1.

Further, in order to diffusely reflect the injected fuel 7, irregularities may be formed on the surface of the jetting protruding surface 9. The uneven stripes may be formed in parallel or in a lattice.

[Brief description of the drawings]

FIG. 1 is a view for explaining a swirl chamber type combustion chamber according to a first embodiment of the present invention. FIG. 1 (A) is a longitudinal sectional view of the swirl chamber type combustion chamber, and FIG. 1 (A) is a sectional view taken along the line BB of FIG.
FIG. 1C is a perspective view of the gas discharging device used in the first embodiment, and FIG.
FIG. 2D is a sectional view taken along line DD of FIG.

FIG. 2 is a view for explaining a gas discharging device used in a second embodiment, FIG. 2 (A) is a perspective view of the gas discharging device, and FIG. 2 (B).
FIG. 3 is a sectional view taken along line BB of FIG.

FIG. 3 is a view for explaining a gas discharging device used in a third embodiment, FIG. 3 (A) is a perspective view of the gas discharging device, and FIG. 3 (B).
FIG. 4 is a sectional view taken along line BB of FIG.

FIG. 4 is a view for explaining a swirl chamber type combustion chamber according to the prior art; FIG. 4 (A) is a longitudinal sectional view of the swirl chamber type combustion chamber;
(B) is a sectional view taken along line BB of FIG. 4 (A).

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Eddy chamber, 2 ... 1 injection port, 3 ... Main combustion chamber, 4 ... Fuel injection nozzle, 5 ... Gas rejection tool, 6 ... 4 injection axis, 7 ... Injected fuel, 8 ... Intersection, 9 ... Injection collision Surface part, 10 ... vortex, 31 ... concaved surface for passage enlargement, 32 ... press-fit air reversal guide surface, 33 ... 2 vortex room extension space, 34 ... part of air,
Reference numeral 40 denotes a nozzle-extended peripheral surface portion, and 41 denotes an upstream-side adjacent peripheral surface portion.

Claims (2)

(57) [Claims] [Claim 1] injection ports in the diesel engine swirl chamber (1)
(2) to communicate with each other tangentially, through its the nozzle holes (2) communicates the upper Symbol swirl chamber (1) into the main combustion chamber (3), the fuel injection nozzle (4 As a swirl chamber (1) ) is faced to, As a swirl chamber (1) in de <br/> swirl chamber type combustion chamber of I over diesel engines pillar shape of the gas reject device (5) provided within, the gas expulsion member (5) axis Heart (17) in the vortex chamber (1)
The injection axis (6) of the injected fuel (7) is aligned with the central axis (18) of the swirling of the vortex flow (10) in the gas exhaust device (5).
The fuel injection nozzle is configured to intersect with the outer peripheral surface of the fuel injection nozzle.
(4) the injected fuel (7) from, crashed into the intersection (8) injection clash surface portion in the vicinity (9) between the injection axis of the outer peripheral surface of the gas expulsion member (5) (6) , configured to scatter reflected, of the outer peripheral surface of the gas expulsion member (5), the upper Symbol nozzle holes (2) and pairs
Vortex (10) on the press-fit air reversal guide surface (32 )
Of the air pushed into the vortex chamber (1) from the nozzle (2) by the press-fit air reversal guide surface (32) . Department (34)
And to guide in a direction against the above-mentioned vortex (10) configured
Forming the eddy chamber type combustion chamber of a diesel engine, characterized in that. 2. An outer peripheral surface of the gas repelling device (5) ,
The swirl chamber from the main combustion chamber (3) via the nozzle (2)
The above-mentioned nozzle (2) through which the air pushed into (1) first passes
The injection port extending side peripheral surface portion that wraps the eddy chamber extending space (33) (40), said forming a passage enlarging recess surface (31), vortex than its passage enlarging recess surface (31) Upstream of (10)
Side with the press-fit air reversal guide surface (32)
Then, the flow (10) of the flow
The swirl-type combustion chamber of a diesel engine according to claim 1, characterized in that the injection blast surface (9) is located downstream .