JP3047210B2 - Diesel engine swirl chamber combustion chamber - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a swirl chamber combustion chamber of a diesel engine.

2. Description of the Related Art A vortex chamber type combustion chamber of a diesel engine of this type has conventionally been disclosed in, for example,
The one disclosed in Japanese Patent Publication No. 2 is known. It is Figure 3
As shown in FIG. 3, the vortex chamber 2 facing the injection nozzle 11 of the fuel injector 10 and the main combustion chamber 6 are communicated via the injection port 5, and the vortex chamber 2 is transmitted from the injection port 5 during the compression stroke of the engine.
The vortex is generated by the air A flowing into the inside, and the mixing of the spray fuel Q and the air A injected from the injection nozzle 11 is promoted. In FIG. 3 , reference numeral 1 denotes a cylinder head, 7 denotes a piston, 8 denotes a suction / exhaust valve, 9 denotes a preheating plug, 12 denotes a nozzle orifice, and 13 denotes a cylinder liner.

[0003]

In the above-mentioned prior art, the injection nozzle 11 of the fuel injector 10 is provided near the inner wall surface inside the swirl flow chamber 2 so as to face the spray fuel Q injected from the injection nozzle 11 and the eddy current. Although it is configured to promote the mixing with A, the mixing between the spray fuel Q and the vortex A is not always sufficient. Further, the burned gas is likely to remain near the injection nozzle 11 in the back of the swirl chamber 2, and the sprayed fuel Q takes in the burned gas and locally lacks air (oxygen). For this reason, smoke (black smoke) may be generated. The present invention has been made in view of such circumstances, and it is an object of the present invention to further promote the mixing of spray fuel and air to prevent generation of smoke.

[0004]

The present invention is configured as follows to solve the above-mentioned problems. The invention according to claim 1 is a vortex chamber type combustion chamber of a diesel engine in which the vortex chamber 2 and the main combustion chamber 6 are communicated via the injection port 5,
A tapered fuel injection port 3 is formed in a recessed inner wall surface of the swirl chamber 2, and an injection nozzle 11 of a fuel injector 10 is provided inside the fuel injection port 3 so as to face the injection nozzle.
The spray fuel Q injected from the nozzle 11 is the tapered fuel
By flowing out into the vortex chamber 2 through the nozzle 3,
The inside of the fuel injection port 3 is configured to have a negative pressure, and the vortex chamber 2 and the inside of the fuel injection port 3 communicate with each other through a fresh air introduction path 4. The portion 4a is opened apart from the fuel injection port 3.

[0005] Further, the invention according to claim 2 is based on claim 1.
In the vortex chamber type combustion chamber of the diesel engine described in (1), the vortex chamber side end 4a of the fresh air introduction passage 4 is opened only on the vortex upstream side of the fuel injection port 3. Here, “the upstream side of the vortex of the fuel injection port 3”
In FIG. 1, air A flowing into the swirl chamber 2 from the injection port 5 is shown.
This means that it is upstream of the fuel injection port 3 when viewed in a direction along the flow of the fuel.

According to a third aspect of the present invention, in the vortex chamber type combustion chamber of the diesel engine according to the first aspect, a plurality of fresh air introduction paths 4 are provided, and the fresh air introduction path 4 is located on the vortex chamber side. The end portion 4a is opened at least on the upstream side and the downstream side of the vortex flow of the fuel injection port 3. Here, “at least” means that the swirl chamber side end 4 a of the fresh air introduction passage 4 is opened on the upstream side and the downstream side of the swirl flow of the fuel injection port 3. Does not exclude the one that opens the swirl-chamber-side end 4a of the fresh air introduction passage 4 around the periphery.

[0007]

According to the present invention, the following functions and effects can be obtained. According to the vortex chamber type combustion chamber according to the first aspect, the tapered fuel injection port 3 is formed to be recessed in the inner wall surface at the inner side of the vortex chamber 2, and the fuel injector 10 provided to face the injection nozzle 11, the injection
The spray fuel Q injected from the nozzle 11 has the above tapered shape.
By flowing out into the swirl chamber 2 through the fuel nozzle 3,
The inside of the fuel injection port 3 is configured to have a negative pressure, and the swirl chamber 2 and the inside of the fuel injection port 3 are connected to the fresh air introduction passage 4.
In the fact that communicates with spray fuel Q injected from the injection nozzle 11 comes between you outflow into the swirl chamber 2 through the tapered fuel injection port 3, together with the back inside of the fuel injection port 3 becomes a negative pressure The new air (hereinafter referred to as fresh air) pressurized into the swirl chamber 2 passes through the fresh air introduction passage 4 to become a negative pressure fuel injection port 3.
Flows into the interior of the interior.

The spray fuel Q subsequently injected from the injection nozzle 11 takes in fresh air flowing into the interior of the fuel injection port 3 and flows out into the swirl chamber 2. Thereby, the mixing of the spray fuel and fresh air is further promoted, and the generation of smoke is prevented. In addition, since the swirl chamber side end 4a of the fresh air introduction passage 4 is opened apart from the fuel injection port 3, the burned gas Q remaining in the vicinity of the outlet of the fuel injection port 3 is discharged by the spray fuel Q. Even if the burned gas flows down, the burned gas is
Does not flow into the interior of the fuel injection port 3 through the nozzle.

According to the swirl chamber type combustion chamber of the second aspect, the swirl chamber side end 4a of the fresh air introduction passage 4 is opened only to the swirl flow upstream side of the fuel injection port 3, so that the swirl flow of the spray fuel is reduced. When the injection pressure is relatively strong, the fresh air introduction path 4
The amount of fresh air that is supplied under pressure to the interior of the fuel nozzle 3 through the nozzle increases, and the mixing of the spray fuel and the fresh air is further promoted. Here, the case where the vortex is relatively strong with respect to the injection pressure of the spray fuel refers to an engine for high-speed rotation or an engine having a relatively long injection port communicating the main combustion chamber and the vortex chamber and having good straight-line guideability. This means that the vortex caused by the pressurization in the compression stroke is strong.

According to the swirl chamber type combustion chamber of the third aspect, the swirl chamber side ends 4a of the plurality of fresh air introduction passages 4 are opened at least on the upstream side of the fuel injection port 3 and on the downstream side of the swirl flow. Even when the vortex is relatively weak with respect to the injection pressure of the spray fuel, necessary and sufficient fresh air is supplied to the inner portion of the fuel injection port 3 through the plurality of fresh air introduction passages 4. Mixing with fresh air is sufficiently promoted. Here, the case where the vortex is relatively weak with respect to the injection pressure of the spray fuel refers to an engine for a low-speed rotation or an engine having a relatively short injection guide communicating the main combustion chamber and the vortex chamber and having a low straight guide property. This refers to the case where the vortex caused by pressurization in the compression stroke is not strong.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a vertical sectional front view of a main part of a swirl chamber type combustion chamber according to Embodiment 1 of the present invention. As shown in FIG. 1, the basic configuration of the vortex chamber type combustion chamber is configured such that a vortex chamber 2 formed in a cylinder head 1 and a main combustion chamber 6 communicate with each other through an injection port 5. Hereinafter, the characteristic configuration of the swirl chamber type combustion chamber according to the first embodiment will be described.

[0012] As shown in FIG. 1, the rear inner wall surface of the swirl chamber 2 is tape path like fuel injection port 3 is formed recessed, this tape
The injection nozzle 11 of the fuel injector 10 faces the inside of the fuel injection port 3 in the shape of a letter P. And swirl chamber 2 and fuel injection port 3
And a plurality of fresh air introduction passages 4, each of the swirl chamber side ends 4 a of these fresh air introduction passages 4 are provided at least on the upstream side and the downstream side of the vortex flow of the fuel nozzle 3. 3
The opening is separated from the opening.

According to the above configuration, the spray fuel Q injected from the injection nozzle 11 flows into the swirl chamber 2 through the tapered fuel injection port 3, but the fuel fuel Q injected from the inner side of the tapered fuel injection port 3. The inside becomes negative pressure due to the outflow of the spray fuel Q, and fresh air pressurized into the swirl chamber 2 flows through the fresh air introduction path 4 into the inside of the fuel injection port 3 which has become negative pressure . Then, the spray fuel Q continuously flowing into the swirl chamber 2 takes in fresh air flowing into the inside of the fuel injection port 3, and the mixing of the spray fuel and the fresh air is further promoted, thereby preventing generation of smoke.

The vortex flow chamber-side end 4a of the fresh air introduction passage 4 is opened at least on the vortex flow upstream side and the vortex flow downstream side of the fuel injection port 3 because the vortex flow is relative to the injection pressure of the spray fuel Q. Even if it is weak, the fresh air is sufficient
And intended to further promote the mixing of the spray fuel Q and the fresh air A. Therefore, not only the vortex upstream side and the vortex downstream side, but also a plurality of vortex chamber side ends 4a may be opened around the fuel injection port 3 as needed.

Further, in the present invention, the end 4a of the fresh air introduction passage 4 on the vortex chamber side is opened apart from the fuel injection port 3.
This is to prevent the burned gas remaining near the outlet of the fuel nozzle 3 from flowing into the interior of the fuel nozzle 3 through the fresh air introduction passage 4 together with fresh air. The burned gas is pushed out by the spray fuel Q flowing down,
Spread.

FIG. 2 is a vertical sectional front view of a main part of a swirl chamber type combustion chamber according to a second embodiment of the present invention. In the second embodiment, FIG.
As shown in FIG. 2, the swirl chamber side end 4a of the fresh air introduction passage 4 is opened only on the upstream side of the swirl flow of the fuel injection port 3, and the other points are configured in the same manner as in the first embodiment (FIG. 1). I have. According to the second embodiment, when the vortex A is relatively strong with respect to the injection pressure of the spray fuel Q, the fresh air pressurized and supplied to the inside of the fuel injection port 3 through the fresh air introduction passage 4 is formed. As a result, the mixing of the spray fuel Q and fresh air is further promoted. That is, the second embodiment is suitable for a high-speed rotation engine.

[0017]

[0018]

[0019]

[Brief description of the drawings]

FIG. 1 is a vertical sectional view of a main part of a swirl chamber type combustion chamber according to a first embodiment of the present invention.

FIG. 2 is a diagram corresponding to FIG. 1 according to a second embodiment of the present invention.

FIG. 3 is a diagram corresponding to FIG. 1 according to a conventional example.

[Explanation of symbols]

2 ... swirl chamber, 3 ... fuel injection port, 4 ... fresh air introduction path, 4a ... end of the new air introduction path on the swirl chamber side, 5 ... injection port, 6 ... main combustion chamber, 1
0: fuel injector, 11: injection nozzle of fuel injector, E:
diesel engine.

Continuation of front page (56) References JP-A-3-124913 (JP, A) JP-A-62-276212 (JP, A) JP-A-6-14440 (JP, U) JP-A-60-41521 (JP , U) Japanese Utility Model Application Showa 59-179230 (JP, U) Japanese Utility Model Application Showa 59-165922 (JP, U) Japanese Utility Model Utility Model 2-1421 (JP, U) (58) Fields surveyed (Int. Cl. ⁷ , DB Name) F02B 19/08-19/18 F02M 61/14 310 F02M 61/18 340

Claims (3)

(57) [Claims] 1. A swirl chamber type combustion chamber of a diesel engine comprising a swirl chamber (2) and a main combustion chamber (6) communicating with each other through an injection port (5). while the recessed form a tapered fuel nozzle holes (3) on the wall, provided a fuel injector to the injection nozzle (10) (11) to face the back inside of the fuel injection port (3), the injection nozzle (11 Spray fuel (Q) injected from)
Passes through the tapered fuel injection port (3) and passes through the vortex chamber.
By flowing into (2), the fuel nozzle (3)
The inside of the back is configured to have a negative pressure, and the vortex chamber (2) communicates with the inside of the fuel injection port (3) through a fresh air introduction path (4). A swirl chamber type combustion chamber for a diesel engine, wherein an end (4a) of the swirl chamber side is opened apart from the fuel injection port (3). 2. The vortex chamber combustion of a diesel engine according to claim 1, wherein the vortex chamber side end (4a) of the fresh air introduction passage (4) is opened only on the vortex upstream side of the fuel injection port (3). Room. 3. A plurality of fresh air introduction paths (4) are provided, and the end (4a) of the fresh air introduction path (4) on the vortex flow chamber side is at least upstream of the fuel injection port (3) and downstream of the vortex flow. The swirl chamber type combustion chamber of a diesel engine according to claim 1, wherein the combustion chamber is open to the inside.