JPH04241721A - 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 against a gas expulsive means in a vortex chamber for scattering, and setting an angle formed by an injection axial center and an injection fuel striking part on an upstream side of the vortex flow to be an acute angle. 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 fuel injected from the fuel injection nozzle 4 is stuck 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.

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. 9, this is a device in which a gas repelling device 102 is provided near 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 9 (
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 8, 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.
It is characterized in that the angle θ formed on the upstream side of is set to be an acute angle.

(Second invention) The second invention is the first invention, in which FIG. 1(D), FIG. 2(B), FIG. 3(B) and FIG. 7(
As shown in B), the jet collision surface portion 9 is
It is characterized by being formed in a convexly curved shape along the turning direction of zero.

(Third invention) In the third invention, in the first invention, as shown in FIG. 4(B), FIG. 5(B), and FIG. 6(B), It is characterized by being formed flat along the swirling direction of the flow 10.

[0013]

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

■ Orient the injection axis 6 of the fuel injection nozzle 4 in a direction that intersects with the gas ejector 5, and the fuel injection nozzle 4
Since the injected fuel 7 collides with the injection collision surface portion 9 of the gas ejector 5 and is reflected and scattered, it is possible to promote the atomization and diffusion of the injected fuel 7. Therefore, it is possible to improve the mixing performance of the injected fuel 7 and air and improve the combustion performance, thereby sufficiently reducing HC and CO, improving the output performance of the engine, and reducing fuel consumption. Can be done.

(2) Since the gas repellent device 5 stores the combustion heat in the swirl chamber 1, the injected fuel 7 that collides with the injection collision surface portion 9 can absorb the heat. For this reason, the whirlpool chamber 1
By promoting the vaporization of the injected fuel 7 within the engine, it is possible to prevent an ignition delay caused by a delay in the vaporization of the injected fuel, thereby effectively preventing the occurrence of diesel knock.

■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,
The injected fuel 7 can be reflected toward the downstream of the eddy flow 10, and the injected fuel 7 can be smoothly involved in the eddy flow 10. For this reason, the mixing performance of the injected fuel 7 and air can be further improved, and as a result, the HC/
It is possible to further ensure a reduction in CO, 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 surface portion 9 is set to an acute angle, 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 expanded compared to the case where the collision area is expanded, and the heat absorbed by the injected fuel 7 from the gas repelling device 5 can be increased. Therefore, the vaporization of the injected fuel 7 in the whirlpool chamber can be further promoted, thereby making it possible to more reliably prevent the occurrence of diesel knock as described in (2) above.

The effects of the second and third inventions are also similar.

[0019]

[Effects of the invention] In the first to third inventions, the following effects ■
Play ~■.

[0020] ■ The injection axis of the fuel injection nozzle is oriented in a direction that intersects with the gas displacement device, so that the fuel injected from the fuel injection nozzle collides with the injection collision surface of the gas displacement device and is reflected and scattered. Therefore, 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. can.

[0021] Since the gas repellent device stores combustion heat in the whirlpool chamber, the injected fuel that collides with the injection collision surface portion can absorb the heat. Therefore, it is possible to promote the vaporization of the injected fuel in the swirl chamber and prevent the ignition delay caused by the delay in the vaporization of the injected fuel, thereby effectively preventing the occurrence of diesel knock.

■Since the angle that the injection axis makes on the upstream side of the eddy flow with respect to the injection collision surface is set to an acute angle, the injected fuel is reflected toward the downstream of the eddy flow, and the injected fuel flows smoothly into the eddy flow. can be involved in. 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 formed by the injection axis with respect to the injection collision surface is set at an acute angle, the injected fuel collides with the injection collision surface from an angle, and the impact area is smaller than that in the case where the injected fuel collides head-on. can spread, increasing the heat that the injected fuel absorbs from the gas displacement device. 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.

[0024]

[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 whirlpool 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 whirlpool 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 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), this injection collision surface portion 9 utilizes the outer circumferential surface of the cylindrical gas repelling tool 5 as it is. Therefore, this injection collision surface portion 9 is
As shown in (D), the shape is convexly curved along the swirling direction of the swirling flow 10, and as shown in FIG. becomes flat along.

Furthermore, in this swirl chamber type combustion chamber 50, in order to reflect the injected fuel toward the downstream side of the swirl flow, 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

In the second to sixth embodiments described below, as shown in FIGS. 2 to 6, the injection impact surface portion 9 of the cylindrical gas repellent device 5 used in the first embodiment is Only the shape of the gas repelling tool 5 is changed, and only the gas repelling tool 5 is shown in the drawing.

(Second and Third Embodiments) In the second and third embodiments, as shown in FIGS. 2 and 3, the first
As in the embodiment, a gas repelling device is used in which the jet collision surface portion 9 is convexly 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).
As shown in FIG.
It is made to have a convex 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.
As shown in FIG.
It is made to have a concave curved shape along the axis 17 direction.

(Fourth Example to Sixth Example) Fourth Example to
In the sixth embodiment, as shown in FIGS. 4 to 6, a gas repelling device is used in which the jet collision surface portion 9 is flat along the swirling direction of the eddy flow 10.

FIG. 4 is a diagram illustrating a gas repellent used in the fourth embodiment. As shown in FIG. 4(A), this gas ejecting tool 5 is made by cutting out a part of the outer peripheral surface of a cylindrical body.
0, and as shown in FIG.
It is made to be flat along the axial center 17 direction.

FIG. 5 is a diagram illustrating a gas repellent used in the fifth embodiment. As shown in FIG. 5(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. 5(B).
0, and as shown in FIG.
It is made to have a concave curved shape along the axis 17 direction.

FIG. 6 is a diagram illustrating a gas repellent used in the sixth embodiment. As shown in FIG. 6(A), this gas ejector 5 is a cylindrical body with a part of its outer peripheral surface removed.
As shown in FIG. 6(B), the injection collision surface portion 9 becomes flat along the swirling direction of the vortex flow 10, and as shown in FIG. It has a convex curved shape along the direction of the axis 17 of the repelling tool 5.

(Seventh Embodiment) FIG. 7 is a diagram for explaining the seventh embodiment. This seventh embodiment is obtained by adding a plurality of constituent elements as described below to the first embodiment. That is, as shown in FIG. 7(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 seventh embodiment, since the inside of the injection collision surface portion 9 of the gas repellent 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.

[0040] Also, in the whirlpool chamber 1, an extension space 33 of the spout 2 is provided.
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 of the eddy flow 10 adjacent to the upstream side when viewed from the passage enlarging concave surface 31, and this guide air reversing guide surface 32 has the following features: 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.

(Seventh Embodiment) FIG. 8 is a diagram for explaining the eighth embodiment. In this embodiment, both left and right sides 2 of the whirl chamber 1 are
0.20 are configured to be shifted closer to the center of the whirlpool chamber 1 than both basic side surfaces 22.22 of the basic shape (spherical shape) 21 of the whirlpool chamber 1, The width dimension 23 between the vortex chambers 1 and 20 is set to a value smaller than the diameter dimension 25 of the vortex flow guide surface 24 located at the center of the inner peripheral surface of the vortex chamber 1 in the left-right direction. According to the eighth embodiment, stagnation of air on both the left and right sides of the eddy flow 10 can be reduced. Therefore, the mixing performance of the injected fuel 7 and air can be improved.

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

Furthermore, 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, unevenness 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 is a diagram illustrating a gas ejector used in the third embodiment, FIG. 3(A) is a perspective view of the gas ejector, and 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 the line B-B in Fig. 3(A).
) is a sectional view taken along line CC.

FIG. 4 is a diagram illustrating a gas ejector used in the fourth embodiment, FIG. 4(A) is a perspective view of the gas ejector, and FIG. 4(B) is a perspective view of the gas ejector.
is a cross-sectional view taken along the line B-B in FIG. 4(A), and FIG.
) is a sectional view taken along line CC.

FIG. 5 is a diagram illustrating a gas ejector used in the fifth embodiment, FIG. 5(A) is a perspective view of the gas ejector, and FIG. 5(B) is a perspective view of the gas ejector.
is a cross-sectional view taken along the line B-B in FIG. 5(A), and FIG.
) is a sectional view taken along line CC.

FIG. 6 is a diagram illustrating a gas ejector used in the sixth embodiment, FIG. 6(A) is a perspective view of the gas ejector, and FIG. 6(B) is a perspective view of the gas ejector.
is a cross-sectional view taken along the line B-B in FIG. 6(A), and FIG.
) is a sectional view taken along line CC.

FIG. 7 is a diagram illustrating a gas repellent used in a seventh embodiment, FIG. 7(A) is a perspective view of the gas repellent, and FIG. 7(B) is a perspective view of the gas repelling tool.
is a cross-sectional view taken along line BB in FIG. 7(A).

FIG. 8 is a diagram corresponding to FIG. 1(B) of the eighth embodiment.

FIG. 9 is a diagram illustrating a whirlpool type combustion chamber according to the prior art, and FIG. 9(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. 9(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 (3)

[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). The jet collides with the jet collision surface portion (9) near the intersection (8) with the jet shaft center (6), and is configured to be reflected and scattered, and the jet collides with the jet collision surface portion (9). A whirlpool combustion chamber for a diesel engine, characterized in that the angle (θ) formed by the axis (6) on the upstream side of the whirlpool (10) is set to be an acute angle. 2. The whirl chamber type diesel engine according to claim 1, wherein the injection collision surface portion (9) is formed in a convexly curved shape along the swirling direction of the whirlpool flow (10). combustion chamber. 3. The whirl chamber combustion for a diesel engine according to claim 1, wherein the injection collision surface portion (9) is formed flat along the swirling direction of the whirlpool flow (10). Room.