JPH04241722A - Vortex chamber type combustion chamber for diesel engine - Google Patents

Abstract

PURPOSE:To improve a mixing condition of injected fuel, a vortex flow and air by striking the fuel injected from a fuel injection nozzle againsat a gas expulsive means in a vortex chamber, setting an angle formed by an injection axial center and an injection fuel striking part to be an acute angle, and recessedly forming the injection fuel striking part. CONSTITUTION:An injection port 2 is tangentially communicated with a vortex chamber 1 of a Diesel engine, while a main combustion chamber 3 is communicated with the vortex chamber 1 through the injection port 2. A fuel injection nozzle 4 is faced to the vortex chamber 1, while a gas expulsive means 5 is arranged on a center of the vortex chamber 1. In the above-mentioned combustion chamber, an injection axial center 6 of the fuel injection nozzle 4 is set in a direction crossing with the gas expulsive means 5. The injected fuel is struck against an injected fuel striking part 9 on an outer peripheral surface of the gas expulsive means 5 and in the vicinity of an intersection 8 with the injection axial center 6. An angle formed by the injected fuel striking part 9 and the injection axial center 6 on an upstream side of a vortex flow 10 is set to be an acute angle. In addition, the injection fuel striking part 9 is recessedly formed along a revolving direction of the vortex flow 10.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a swirl chamber combustion chamber for a diesel engine.

0002

BACKGROUND OF THE INVENTION In a whirlpool type combustion chamber of a diesel engine, the whirlpool chamber has its nozzle tangentially communicated with the main combustion chamber through the nozzle, and a fuel injection nozzle is connected to the whirlpool chamber. The structure that faces the front is adopted as a general structure.

By the way, in a whirlpool type combustion chamber having such a structure, unburned gas and burnt gas having different masses are separated in the whirlpool chamber by centrifugal force based on the swirling of the whirlpool, and the center of the whirlpool is separated. Burnt gas with a small mass gathers in the vicinity, and this becomes locally high temperature, promoting the generation of NOX. For this reason, reducing NOx has become one of the important issues in the whirlpool combustion chamber.

0004

2. Description of the Related Art Conventionally, there is a technique disclosed in Japanese Utility Model Application Publication No. 139030/1983 as a technique for reducing NOx. As shown in FIG. 5, this is a device in which a gas repelling device 102 is provided in the vicinity of the center of a whirlpool chamber 101. According to this, it is possible to prevent the burnt gas from flowing into the vicinity of the center of the whirlpool chamber 101, thereby preventing the separation of unburnt gas and burnt gas within the whirlpool chamber 101. Room 1
It is possible to prevent the formation of a high-temperature region due to the collection of burnt gases in the 01, thereby reducing the amount of NOx generated.

[0005] Regarding this prior art, the above-mentioned publication discloses that since the gas repelling device 102 is provided in the vortex chamber 101, the velocity distribution of the eddy flow can be made uniform, and thereby the fuel distribution can be made uniform. It is explained that the amount of HC and CO generated can be reduced. Also, Figure 5 (
As shown in B), by narrowing both ends of the gas ejector 102 in particular, combustion gas can be smoothly ejected from the swirl chamber 101 to the main combustion chamber, thereby reducing combustion in the main combustion chamber. It is explained that this can be done smoothly, thereby improving the output of the engine and reducing fuel consumption.

[0006] However, this prior art only suggests means for improving eddy flow and combustion gas, and only improves HC/combustion gas.
The following problems arise because there is a lack of ingenuity in making the injected fuel finer and promoting its diffusion, which are the most important factors for reducing CO, improving engine output performance, and reducing fuel consumption.

[0007]

Problems to be Solved by the Invention In the above-mentioned prior art, it is not possible to achieve sufficient fineness and diffusion of the injected fuel, and therefore no improvement in the mixing performance of the injected fuel and air can be expected. For this reason, combustion performance cannot be sufficiently improved, and HC/C
It is not possible to sufficiently reduce O, improve engine output performance, and reduce fuel consumption.

An object of the present invention is to reduce NOx and at the same time sufficiently improve the output performance of the engine by making the injected fuel finer and promoting its diffusion.

[0009]

[Means for Solving the Problems] (First Invention) As shown in FIG. 1(A), the first invention has a jet nozzle 2 tangentially connected to a whirlpool chamber 1 of a diesel engine. A diesel engine is constructed in which the whirlpool chamber 1 is communicated with the main combustion chamber 3 through the whirlpool chamber 1, the fuel injection nozzle 4 is faced to the whirlpool chamber 1, and a gas displacement device 5 is provided in the vicinity of the center of the whirlpool chamber 1. The swirl chamber type combustion chamber has the following features.

That is, as shown in FIGS. 1 to 4, within the swirl chamber 1, the injection axis 6 of the fuel injection nozzle 4 is oriented in a direction intersecting the gas displacement device 5, and the fuel injection nozzle 4 is The injected fuel 7 collides with the injection collision surface portion 9 near the intersection 8 with the injection axis 6 on the outer circumferential surface of the gas ejector 5, and is reflected and scattered. The jet axis 6 has a vortex flow 10 with respect to the surface portion 9.
The angle θ formed on the upstream side of the jet is set to an acute angle, and the injection collision surface portion 9 is formed in a concave shape along the swirling direction of the vortex flow 10.

(Second Invention) In the second invention, in the first invention, as shown in FIG.
It is characterized in that it is formed in the shape of a front-widening groove in which the width of the groove becomes gradually narrower as it progresses toward the downstream side of the eddy flow 10.

0012

[Operation] The operation of the first invention will be explained based on FIG. 1(D).

■ The injection axis 6 of the fuel injection nozzle 4 is oriented in a direction that intersects with the gas displacement device 5, and the injected fuel 7 from the fuel injection nozzle 4 collides with the injection collision portion 9 of the gas displacement device 5 and is reflected. Since it is configured to scatter, the injected fuel 7 can be made finer and diffused. Therefore, it is possible to improve the mixing performance of the injected fuel 7 and air, and improve the combustion performance, thereby making it possible to sufficiently reduce HC and CO, improve engine output performance, and reduce fuel consumption. can.

[0014] Since the gas repelling device 5 stores the combustion heat in the swirl chamber 1, the injected fuel 7 that collides with the injection collision portion 9 can absorb the heat. Therefore, vaporization of the injected fuel 7 within the swirl chamber 1 is promoted, ignition delay due to delay in vaporization of the injected fuel is prevented, and diesel knock can be effectively prevented from occurring.

■Since the angle θ formed by the injection axis 6 on the upstream side of the eddy flow 10 with respect to the injection collision surface portion 9 is set to an acute angle,
Reflecting the injected fuel 7 toward the downstream side of the eddy flow 10,
The injected fuel 7 can be smoothly drawn into the vortex 10. Therefore, it is possible to improve the mixing performance of the injected fuel 7 and air, and as a result, the HC/C
It is possible to further ensure a reduction in O, an improvement in engine output performance, and a reduction in fuel consumption.

■ Since the angle θ formed by the injection axis 6 with respect to the injection collision portion 9 is set to an acute angle, the case where the injected fuel 7 collides with the injection collision surface portion 9 obliquely and the injected fuel 7 collides head-on. The collision area is wider compared to . In addition, since the injection collision surface portion 9 is formed in a concave curved shape along the swirling direction of the eddy flow 10, the injection collision surface portion 9 is formed in a convex curved shape or a flat shape. The collision area of the injected fuel 7, which is injected in a divergent direction, increases by the distance from 4. In this way, the area where the injected fuel 7 collides with the injection collision portion 9 is expanded, and the heat absorbed by the injected fuel 7 from the gas repelling tool 5 can be increased. Therefore, the vaporization of the injected fuel 7 within the swirl chamber 1 can be promoted, thereby making it possible to further ensure the prevention of diesel knock described in the above (2).

(Second invention) The second invention operates in the following manner in addition to the functions (1) to (4) of the first invention.

■As shown in FIG. 3, the injection collision surface portion 9 is formed in the shape of a front-widening groove whose groove width gradually becomes wider as it progresses toward the downstream side of the eddy flow 10.
The injected fuel 7 that is reflected and scattered is guided by the groove walls 26 and 26 of the injection collision surface portion 9 to prevent the injected fuel 7 from scattering unevenly or unevenly, and to ensure that the injected fuel 7 flows into the eddy flow 10. It can be thrown towards the enemy. Therefore, it is possible to improve the mixing performance of air and the injected fuel 7, which further ensures the reduction of HC and CO, improvement of engine output performance, and reduction of fuel consumption as described in (■) above. can do.

[0019]

[Effects of the invention] (First invention) The first invention has the following effects ■
Play ~■.

■The injection axis of the fuel injection nozzle is oriented in a direction that intersects with the gas repellent, and the fuel injected from the fuel injection nozzle collides with the injection collision part of the gas repellent and is reflected and scattered. , it is possible to promote atomization and diffusion of the injected fuel. Therefore, it is possible to improve the mixing performance of the injected fuel and air and improve the combustion performance, which can sufficiently reduce HC and CO, improve engine output performance, and reduce fuel consumption. .

[0021] Since the gas repelling device stores combustion heat in the whirlpool chamber, the injected fuel 7 that collides with the injection collision part can absorb the heat. Therefore, vaporization of the injected fuel in the swirl chamber is promoted, ignition delay due to delay in vaporization of the injected fuel is prevented, and diesel knock can be effectively prevented from occurring.

■Since the angle formed by the injection axis on the upstream side of the eddy flow with respect to the injection collision surface is set at an acute angle, the injected fuel is reflected toward the downstream side of the eddy flow, and the injected fuel flows into the eddy flow. It can be rolled up smoothly. Therefore, it is possible to improve the mixing performance of the injected fuel and air, which further ensures the reduction of HC and CO, the improvement of engine output performance, and the reduction of fuel consumption, as described in effect ① above. can do.

■Since the angle between the injection axis and the injection collision part is set at an acute angle, the injected fuel collides with the injection collision surface obliquely, and the collision area is smaller than when the injected fuel collides head-on. spread. In addition, since the injection collision surface portion is formed in a concave curved shape along the swirling direction of the eddy flow, the injection collision surface portion is further away from the fuel injection nozzle compared to a case where the injection collision surface portion is formed in a convex curved shape or a flat shape. Therefore, the collision area of the injected fuel spreads out. In this way, the area where the injected fuel collides with the injection collision portion is expanded, and the heat absorbed by the injected fuel from the gas repelling device can be increased. Therefore, the vaporization of the injected fuel within the whirlpool chamber can be promoted, thereby making it possible to more reliably prevent the occurrence of diesel knock as described in the above-mentioned effect ①.

(Second invention) In addition to the effects (1) to (2) of the first invention, the second invention provides the following effect (2).

■Since the injection collision surface portion is formed in the shape of a front-widening groove whose groove width gradually becomes wider as it advances toward the downstream side of the eddy flow, the injected fuel that is reflected and scattered by the injection collision surface portion is transferred to the injection collision surface. By guiding the injected fuel with both groove walls, it is possible to prevent the injected fuel from scattering unevenly or unevenly, and to reliably scatter the injected fuel toward the eddy flow. Therefore, it is possible to improve the mixing performance of air and injected fuel, which further ensures the reduction of HC and CO, the improvement of engine output performance, and the reduction of fuel consumption, as described in effect ① above. can do.

[0026]

[Embodiment] An embodiment of the present invention will be explained based on the drawings. (First Embodiment) FIG. 1 is a diagram illustrating a whirlpool type combustion chamber according to a first embodiment of the present invention, and FIG. 1(A) is a longitudinal sectional view of the whirlpool type combustion chamber, and FIG. 1(B) 1(A) is a cross-sectional view taken along the line B-B in FIG. 1(A), FIG. 1(C) is a perspective view of the gas repellent used in the first embodiment, and FIG. 1(D) is a cross-sectional view taken along the line D-D in FIG. 1(C). Figure, Figure 1 (E
) is a sectional view taken along line E-E in FIG. 1(D).

In FIG. 1(A), reference numeral 50 indicates a spiral combustion chamber of a diesel engine, which is constructed as follows. As shown in FIG. 1(A), 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
A whirlpool chamber 1 is formed within the cylinder head 14, and the upper half of the whirlpool chamber 1 is formed within the wall of the cylinder head 14, and the lower half of the whirlpool chamber 1 is formed within the nozzle mouthpiece 15 fitted into the cylinder head 14. is formed. A nozzle 2 is formed in the bottom wall of the nozzle nozzle 15 and communicates tangentially with the vortex chamber 1, and the vortex chamber 1 is communicated with the main combustion chamber 3 via the nozzle 2. A fuel injection nozzle 4 faces inside the swirl chamber 1.

In this swirl chamber type combustion chamber 50, in order to reduce the amount of NOx generated, a gas repelling device 5 is provided in the vicinity of the center of the swirl chamber 1, as shown in FIGS. 1(A) and (B). There is. As shown in FIG. 1(C), this gas ejector 5 has a cylindrical shape, and as shown in FIG. It is suspended horizontally along the The axis 17 of the gas ejector 5 is aligned with the center axis 18 of rotation of the eddy flow 10.

In addition, in this swirl chamber type combustion chamber 50, in order to promote finer atomization and diffusion of the injected fuel, as shown in FIG.
The injected fuel 7 from the fuel injection nozzle 4 collides with the injection collision surface portion 9 near the intersection 8 with the injection axis 6 on the outer peripheral surface of the gas ejector 5, and is reflected. It is configured so that it scatters.

As shown in FIG. 1(C), the gas repelling device 5 is a cylindrical body with a part of its outer circumferential surface removed, and the jet collision surface portion 9 has a eddy flow as shown in FIG. 1(D). 10, and as shown in FIG.
It is made to be flat along the direction.

In addition, in this whirlpool type combustion chamber 50, in order to reflect the injected fuel toward the downstream side of the whirlpool, as shown in FIG.
As shown in (D), the angle θ formed by the injection axis 6 on the upstream side of the eddy flow 10 with respect to the injection collision surface portion 9 is set to be an acute angle. Reference numeral 19 indicates the injection collision surface portion 9 at the intersection 8.
is the tangent line of

[0032] The second and third embodiments shown below are as follows:
As shown in FIGS. 2 and 3, only the shape of the injection collision surface portion 9 of the cylindrical gas repelling tool 5 used in the first embodiment has been changed, and the gas repelling tool Only 5 is shown.

(Second Embodiment and Third Embodiment) In the second and third embodiments, as shown in FIGS. 2(B) and 3(B), as in the first embodiment, the injection collision A gas repelling tool is used in which the surface portion 9 is concavely curved along the swirling direction of the eddy flow 10.

FIG. 2 is a diagram illustrating a gas repellent used in the second embodiment. As shown in FIG. 2(A), this gas ejector 5 has a part of the outer circumferential surface of a cylindrical body cut out, and the jet collision surface portion 9 has a eddy flow 1 as shown in FIG. 2(B).
0, and as shown in FIG.
It is made to have a concave curved shape along the axis 17 direction.

FIG. 3 is a diagram illustrating a gas repellent used in the third embodiment. This gas ejector 5 has a cylindrical body with a part of its outer circumferential surface section removed as shown in FIG.
0, and as shown in FIG.
It is made to have a concave curved shape along the axis 17 direction. Further, as shown in FIG. 3(D), the injection collision surface portion 9 is formed in the shape of a front-widening groove whose groove width becomes wider as it progresses toward the downstream side of the eddy flow 10.

(Fourth Embodiment) FIG. 4 is a diagram illustrating a fourth embodiment. The fourth embodiment has the following components added to the first embodiment. That is, as shown in FIG. 4(B), a hollow portion 30 is formed in the gas displacement device 5, and a passage enlarging concave surface 31 and a press-in air reversing guide surface 32 are formed on the lower side of the outer peripheral surface of the gas displacement device 5. was formed.

In this fourth embodiment, since the inside of the injection collision surface portion 9 of the gas repelling device 5 is formed into a hollow shape by the hollow portion 30, the temperature of the injection collision surface portion 9 increases quickly immediately after starting. Therefore, it is possible to ignite quickly even in cold weather, thereby improving the warming performance.

[0038] Furthermore, an extension space 33 of the spout 2 in the whirlpool chamber 1
Since the passage enlarging concave surface 31 is formed on the circumferential surface portion of the nozzle extension side of the gas ejector 5 that overlaps with the nozzle nozzle 2, the passage cross-sectional area of the extension space 33 of the nozzle nozzle 2 is expanded. Therefore, the resistance when the air pushed into the vortex chamber 1 from the nozzle 2 passes through the extension space 33 of the nozzle 2 is reduced, which increases the flow velocity of the vortex 10 and improves the mixing of the injected fuel 7 and air. Improves performance.

Further, a press-in air reversing guide surface 32 is formed on the upstream side adjacent circumferential surface portion adjacent to the upstream side of the eddy flow 10 when viewed from the passage enlarging concave surface 31, and this guide air reversing guide surface 32 is Since the shape is formed to guide the part 34 of the air pushed into the vortex chamber 1 from the nozzle 2 in the direction opposite to the eddy flow 10, the part 34 of the air forced from the nozzle 2 collides with the eddy flow 10. be able to. Therefore, minute eddies can be generated within the eddy flow 10, thereby improving the mixing performance of the injected fuel 7 and air.

Although the embodiments of the present invention are as described above, the present invention is not limited to the above embodiments. For example, one or a combination of two or more of the components added in the fourth embodiment may be added to the first to third embodiments.

Further, the gas repellent 5 is not limited to a columnar shape, but may be spherical or other block-shaped. In this case, it may be supported by a support rod or the like protruding from the peripheral wall of the whirlpool chamber 1.

Furthermore, in order to diffusely reflect the injected fuel 7, uneven lines may be formed on the surface of the injection collision surface portion 9. These uneven stripes may be formed in parallel or in a lattice shape.

[Brief explanation of the drawing]

FIG. 1 is a diagram illustrating a whirlpool type combustion chamber according to a first embodiment of the present invention, where FIG. 1(A) is a longitudinal cross-sectional view of the whirlpool type combustion chamber, and FIG. 1(B) is a diagram. 1(A) BB line cross-sectional view, Figure 1
(C) is a perspective view of the gas ejector used in the first embodiment, FIG.
(D) is a sectional view taken along the line DD in FIG. 1(C), and FIG. 1(E) is a sectional view taken along the line EE in FIG. 1(D).

[Fig. 2] Fig. 2 is a diagram illustrating a gas ejector used in the second embodiment, and Fig. 2(A) is a perspective view of the gas ejector; Fig. 2(B) is a perspective view of the gas ejector.
is a sectional view taken along the line B-B in Fig. 2(A), and Fig. 2(C) is a sectional view taken along the line B-B in Fig. 2(A).
) is a sectional view taken along line CC.

[Fig. 3] Fig. 3 is a diagram for explaining a gas ejector used in the third embodiment, Fig. 3(A) is a perspective view of the gas ejector; Fig. 3(B) is a perspective view of the gas ejector.
is a sectional view taken along the line B-B in Fig. 3(A), and Fig. 3(C) is a sectional view taken along line B-B in Fig. 3(A).
), and FIG. 3(D) is a sectional view taken along the line C-C of FIG. 3(B).

FIG. 4 is a diagram illustrating a gas repelling tool used in the fourth embodiment, FIG. 4(A) is a perspective view of the gas repelling tool, and FIG. 4(B)
is a sectional view taken along line BB in FIG. 4(A).

FIG. 5 is a diagram illustrating a whirlpool type combustion chamber according to the prior art, and FIG. 5(A) is a longitudinal cross-sectional view of the whirlpool type combustion chamber;
(B) is a sectional view taken along the line BB in FIG. 5(A).

[Explanation of symbols]

1... Whirl chamber, 2... Nozzle nozzle 1, 3... Main combustion chamber, 4... Fuel injection nozzle, 5... Gas ejector, 6... Injection axis center of 4, 7... Injected fuel, 8... Intersection, 9... Injection collision Surface part, 10... Eddy flow, θ... Angle.

Claims (2)

[Claims] Claim 1: A nozzle (2) thereof is tangentially communicated with a whirlpool chamber (1) of a diesel engine, and the whirlpool chamber (1) is communicated with a main combustion chamber (3) through the nozzle (2). ,
In a whirlpool-type combustion chamber of a diesel engine, a fuel injection nozzle (4) faces the whirlpool chamber (1), and a gas repellent (5) is provided near the center of the whirlpool chamber (1). Within the swirl chamber (1), the fuel injection nozzle (4
) is oriented so that the injection axis (6) of the gas ejector (5) intersects with the gas ejector (5), and the injected fuel (7) from the fuel injection nozzle (4) is directed toward the outer peripheral surface of the gas ejector (5). collides with the injection collision surface portion (9) near the intersection (8) with the injection axis center (6), and is configured so that the injection collision surface portion (9) is reflected and scattered. The angle (θ) formed by the center (6) on the upstream side of the eddy flow (10) is set to be an acute angle, and the injection collision surface portion (9) is formed into a concave curved shape along the swirling direction of the eddy flow (10). A swirl chamber type combustion chamber of a diesel engine is characterized by being formed in. 2. The jet collision surface portion (9) is formed in the shape of a front-widening groove in which the width of the groove gradually increases as it advances downstream of the eddy flow (10). The spiral combustion chamber of the diesel engine described in .