JPH1054243A - Volute chamber type combustion chamber for diesel engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase air utilization rate by supplying flux to the central part of a volute chamber. SOLUTION: This combustion chamber is formed so that air in a main combustion chamber 4 may flows into a volute chamber 5 from a jetting hole 8, forming a volute main flux 10. A guide groove 11 is recessed along a volute chamber inner periphery 5a on which the main flux 10 runs. An inner bottom in a final end range is formed so as to narrower as it approaches the final end by an inclined part 12. The secondary flux 15 guided by the guide groove 11 is formed so as to be deviated toward the central part of the volute chamber 5. With the above constitution, the secondary flux 15 passing through the guide groove 11 from the main flux 10 is branched, and the secondary flux 15 is deviated toward the center of the volute chamber by the inclined part 12, therefore, it is possible to increase air utilization rate as a result of the flux being supplied to the central part of the volute chamber.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vortex chamber type combustion chamber of a diesel engine, and more particularly, to a diesel engine in which air in a main combustion chamber flows into the vortex chamber while forming a vortex main flux. It relates to a vortex chamber type combustion chamber.

[0002]

2. Description of the Related Art In a conventional vortex chamber type combustion chamber of a diesel engine, as shown in FIG.
4 is formed, and compressed air pushed in from the main combustion chamber 104 through the injection holes 108 in the compression step is caused to flow into the vortex chamber 105 as a vortex main flux 110, so that air and It is configured to mix fuel.

[0003]

However, in the above prior art, the flow rate of the main flux 110 is reduced near the center O of the vortex chamber 105, so that the flow of air and the injected fuel 116 near the center O is reduced. Insufficient mixing. For this reason, the air utilization rate in the vortex chamber 105 decreases, and problems such as a decrease in combustion performance and generation of unburned harmful components are likely to occur.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above problems, and has as its object to provide a vortex chamber type combustion chamber of a diesel engine which can increase the air utilization rate in the vortex chamber.

[0005]

According to a first aspect of the present invention, there is provided a vortex chamber type combustion chamber of a diesel engine for achieving the above object.
For example, referring to FIGS. 1 and 2, a vortex chamber 5 is provided in a cylinder head 2 of a diesel engine, and the vortex chamber 5 communicates with a main combustion chamber 4 through an injection hole 8 so that air in the main combustion chamber 4 is discharged. In a vortex chamber type combustion chamber of a diesel engine configured to form and flow into the vortex chamber 5 from the injection hole 8 into the vortex chamber 5, the vortex chamber circumferential surface 5a is guided along the flow direction of the main flux 10 in the vortex chamber peripheral surface 5a. A groove 11 is recessed, and the inner bottom 11c of the terminal end region 11b of the guide groove 11 is formed so as to become shallower toward the terminal end, and the flux guided by the guide groove 11 (secondary flux) 15) is configured to be deflected toward the center of the vortex chamber 5.

A vortex chamber type combustion chamber of a diesel engine according to claim 2 will be described with reference to FIGS. 3 and 4, for example, in which a vortex chamber 5 is provided in a cylinder head 2 of a diesel engine.
The vortex chamber 5 is communicated with the main combustion chamber 4 through the injection hole 8, and the air in the main combustion chamber 4 is formed from the injection hole 8 into the vortex chamber 5 into the vortex chamber 5 while forming a main flux 31. In the vortex chamber type combustion chamber of the engine, the injection hole wall surface 28 on the side where air first flows from the injection hole 8 into the vortex chamber 5 has a predetermined basic shape (arc 35).
By forming the injection hole wall surface 27 on the opposite side of the injection hole 8 according to the flat basic shape (elliptical sphere 22) flatter than the predetermined basic shape (arc 35). The height position of the hole wall surface 27 is set higher than the injection hole wall surface 28 on the side where air flows first.

[0007]

According to the first aspect of the present invention, in the case of the vortex chamber type combustion chamber of the diesel engine, the guide groove is recessed so that the main flux flowing through the peripheral surface of the vortex chamber flows through the guide groove.
The next flux 15 is branched. That is, the main flux 10 flows with a certain extent on the peripheral surface 5 a of the vortex chamber, but the main flux 10 in the portion where the guide groove 11 is recessed flows in the guide groove 11 and becomes the secondary flux 15. Due to the generation of the secondary flux 15, a turbulent flow region is generated between the main flux 10 and the secondary flux 15 to generate a small vortex, and the air and the injected fuel 16 are mixed well.

The inner bottom 11c of the end portion 11b of the guide groove 11 is formed so as to become shallower toward the end thereof, and the secondary flux 15 guided by the guide groove 11 Since it is configured to be deflected toward the center, the generated minute vortex is supplied to the center of the vortex chamber. As described above, the generation of the minute vortex is promoted, and the secondary flux 15 guided by the guide groove 11 is supplied to the center of the vortex chamber, so that the air utilization rate at the center of the vortex chamber can be increased. .

In the case of the vortex chamber type combustion chamber of the diesel engine according to the second aspect, the height position of the injection hole wall surface 27 on the opposite side is set higher than the injection hole wall surface 28 on the side where air flows first. The main flux 31 is supplied to the center of the vortex chamber 5 according to the flat basic shape (the elliptical sphere 22), so that the air and the injected fuel are sufficiently mixed also in the center of the vortex chamber.

[0010]

As described above, according to the first aspect of the present invention, the following specific effects can be obtained. (A) Since a small vortex flow can be supplied to the center of the vortex chamber, the air utilization rate in the vortex chamber can be increased, and effects such as improved combustion performance and reduced unburned harmful components can be obtained. (B) By setting the width and depth of the guide groove, the branching ratio between the main flux and the secondary flux can be set, and the secondary angle can be set by setting the inclination angle of the inner bottom of the terminal area. Since the flow direction of the flux can be adjusted, it can be widely applied to combustion chambers of various configurations.

(C) It can be realized by a simple processing simply by forming a guide groove in the peripheral wall of the vortex chamber, and can be implemented at low cost. According to the second aspect of the present invention, since the main flow is configured to flow into the central portion of the vortex chamber, it is possible to generate a turbulent air flow in the central portion of the vortex chamber to generate a micro vortex. Therefore, it is possible to increase the air utilization rate in the vortex chamber, and to achieve a specific effect of improving combustion performance and reducing unburned harmful components.

[0012]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a first embodiment of the present invention. FIG. 1 is a view for explaining a first embodiment of a vortex chamber type combustion chamber of a diesel engine according to the present invention. FIG. 1 (A) is a longitudinal sectional view, and FIG. 1 (B) is FIG.
FIG. 1A is a view taken along the line BB of FIG. 1, and FIG.
FIG. 1D is an enlarged sectional view taken along line DD of FIG. 1B, and FIG. 1E is a view showing a flow of a flux in the vortex chamber. FIG. 2A is a developed plan view of the guide groove, and FIG.
FIG. 2B is a sectional view taken along line EE of FIG.

As shown in FIG. 1 (A), a cylinder head 2 is mounted on the upper side of a cylinder 1 of a vertical diesel engine, a piston 3 is fitted inside the cylinder 2, and a main body is provided between the piston 3 and the cylinder head 2. A combustion chamber 4 is formed.
A spherical vortex chamber 5 is provided in the cylinder head 2, and an injection nozzle 6 of a fuel injection pump projects into the vortex chamber 5 from above the cylinder head 2. A vortex chamber base 7 is provided below the cylinder head 2 in correspondence with the vortex chamber 5, and an injection hole 8 is provided through the vortex chamber base 7, so that the main combustion chamber 4 and the vortex chamber 5 are formed.
And communicates. The compressed air pushed in from the main combustion chamber 4 through the injection hole 8 in the compression step is configured to flow in a spiral main flux as shown by an arrow 10 in FIG. is there.

In addition, a V-shaped guide groove 11 is recessed from a predetermined position above the inner wall of the vortex chamber 5 along the direction in which the main stream 10 flows. Since the vortex chamber 5 is spherical, the guide groove 11 is formed in a substantially elliptical shape so as to protrude outward from the peripheral surface 5a of the vortex chamber. As shown in FIG.
The tip region 11a has a tapered shape in which the width of the groove is narrower toward the tip, and reaches the groove bottom 11c by an inclined portion 13 that gradually becomes deeper from the tip as shown in FIG. 2 (B). Is formed. In addition, an inclined portion 12 that gradually becomes shallow from the groove bottom 11c and reaches the vortex chamber wall surface 5a is formed in the terminal end region 11b of the guide groove 11.

Next, the operation of the vortex chamber type combustion chamber will be described. The air supplied to the main combustion chamber 4 via the intake passage of the engine flows into the vortex chamber 5 while forming a main flux 10 in a compression process. In this case, since the guide groove 11 is recessed in the inner peripheral surface 5a of the vortex chamber 5, as shown in FIG. Is another flux (hereinafter referred to as secondary flux 15)
Branches. When the secondary flux 15 flows in the guide groove 11, a turbulent flow region is generated between the main fluxes 10, and a minute vortex is generated.

The secondary flux 15 flows through the guide groove 11 while generating a small eddy current, and the terminal area 11b of the guide groove 11
Reach Since the inclined portion 12 is formed in the terminal region 11b, the secondary flux 15 is deflected by the inclined portion 12,
It flows toward the center of the vortex chamber. Therefore, in the configuration of the present embodiment, a secondary flux 15 accompanied by a small vortex toward the center of the vortex chamber can be formed separately from the main flow velocity 10,
Even in the center of the vortex chamber, the air is uniformly and uniformly mixed with the injected fuel 16. By this action, the air utilization rate in the vortex chamber 5 can be increased, and the combustion performance of the engine can be improved.

[0017]

Embodiment 2 FIG. 3 is a view for explaining a second embodiment of a vortex chamber type combustion chamber of a diesel engine according to the present invention. FIG. 3 (A) is a longitudinal sectional view, and FIG. FIG. 4 is a view taken along line BB of FIG. FIG. 4 is a view for explaining the structure of the vortex chamber in this embodiment.

Also in the vortex chamber type combustion chamber according to this embodiment, a vortex chamber 5 is provided in the cylinder head 2, a vortex chamber base 7 is provided corresponding to the vortex chamber 5, and an injection hole is provided in the vortex chamber base 7. 8, the main combustion chamber 4 and the vortex chamber 5 are communicated. As shown in FIG. 4, the upper half portion of the vortex chamber 5, that is, the portion provided in the cylinder head 2 is a hemisphere 21 having a radius r1 around O.

The lower half of the vortex chamber 5, that is, the vortex chamber base 7
Has a basic shape of an elliptical sphere 22 which is flatter than a sphere. After the injection hole 8 is formed in the ellipsoidal sphere 22, the inner peripheral surface portion of the ellipse on the right side of the injection hole (the side where air flows in immediately) is cut with an arc of a small circle 23 having a radius r2, and the arc wall surface 24 and the elliptical wall surface 25 are formed. Is connected by the connecting wall 26 so as to be smoothly continuous with the radius r1.
Arc 35. On the other hand, since the left side wall 27 of the injection hole (the side reached after the flux turns) uses the wall surface of the elliptical sphere 22 as it is, the height position of the left side wall 27 of the injection hole is
It is higher by d than the height position of the injection hole right side wall 28.

Next, the operation of the vortex chamber type combustion chamber will be described. The air supplied to the main combustion chamber 5 through the intake passage of the engine flows into the vortex chamber 5 in the compression process to form a vortex main flow velocity 31 (see the reference numeral 31 in FIG. 3A). In this case, the main flux 31 that has swirled in the vortex chamber 5 and reached the injection hole left side wall 27 is deflected by the injection hole left side wall 27 and reaches the center of the vortex chamber, so that the main flux 31 passes through a complete sphere. As compared with the swirling, the vortex chamber can be supplied with the flux at the center, and the airflow at the center of the vortex chamber is disturbed. Due to the turbulence of the airflow, a large number of minute vortices are formed, and even in the center of the vortex chamber, the air is evenly mixed with the injected fuel, so that the air utilization rate in the vortex chamber can be increased.

[0021]

Embodiment 3 FIG. 5 is a view for explaining a third embodiment of a vortex chamber type combustion chamber of a diesel engine according to the present invention. FIG. 5 (A) shows a main flux and a sub flux in the vortex chamber. FIG. 5B is a view schematically illustrating the inflow of the vortex chamber, and FIG. 5B is an external view of the vortex chamber base viewed from the main combustion chamber. The feature of the third embodiment is that in the configuration of the first embodiment or the configuration of the second embodiment, the injection holes are provided along the main injection hole 8 and the left and right sides of the main injection hole 8. And the compressed air of the main combustion chamber is transferred from the main injection hole 8 and the sub injection holes 41, 41 to the vortex chamber 5.
And the axes 45 and 45 of the sub-injection holes 41 intersect with the points configured to be supplied by the main flow velocity 10 and the sub-flow rates 43 and 43, respectively. And two sub-flow rates 4 on both sides of the main flow rate 10 in the vortex chamber 5.
3 is made to collide.

When the configuration of the first embodiment is adopted in the third embodiment, the guide groove 11 is recessed in the peripheral wall of the vortex chamber along the main flux 10. In this case, the main flux 10 is affected by two sub-fluxes 43 and one secondary flux (not shown in FIG. 5), and the main flux 10 is on both sides, the front-rear direction (the direction in which the secondary flux can be performed). Vortex flow can be formed in the vortex chamber 5, and the air utilization rate in the vortex chamber 5 can be further increased.

Also in the case where the configuration of the second embodiment is adopted in the third embodiment, a small eddy current can be formed in both sides of the main flux 10 by the action of the sub-fluxes 43, 43, and the step d ( 4), the main flux 10 can be supplied toward the center of the vortex chamber 5, and the air utilization rate can be increased.

The present invention is not limited to the above embodiment, and various design changes can be made without departing from the scope of the present invention. Hereinafter, such an embodiment will be described. (1) In the first embodiment, a guide groove based on a V-shape is adopted, but a rectangular or arc-shaped guide groove may be used. In the first embodiment, only one guide groove is formed on the peripheral surface of the vortex chamber. However, since the main flux flows into the vortex chamber while expanding in the width direction, a plurality of guide grooves are provided corresponding to the expansion. A groove may be formed.

(2) In the second embodiment, the basic shape of the lower half portion formed in the vortex chamber base for allowing the main flux to flow toward the center is set to be an elliptical sphere that is flatter than a sphere. However, the present invention is not limited to an elliptical sphere, but is not particularly limited as long as the height of the left wall surface of the injection hole is higher than the height of the right wall surface of the injection hole.

[Brief description of the drawings]

FIG. 1 is a view for explaining a first embodiment of a vortex chamber type combustion chamber of a diesel engine according to the present invention, and FIG.
1A is a longitudinal sectional view, FIG. 1B is a view taken along line BB of FIG. 1A, FIG. 1C is an enlarged sectional view taken along line CC of FIG. (D) is an enlarged sectional view taken along line DD of FIG. 1 (B), and FIG. 1 (E) is a view showing a flow of a flux in the vortex chamber.

FIG. 2 (A) is a developed plan view of a guide groove, and FIG. 2 (B).
FIG. 3 is a sectional view taken along line EE of FIG.

FIG. 3 is a view for explaining a second embodiment of a vortex chamber type combustion chamber of a diesel engine according to the present invention, and FIG.
3A is a longitudinal sectional view, and FIG. 3B is a view taken along line BB of FIG. 3A.

FIG. 4 is a view for explaining a structure of a vortex chamber in a second embodiment.

FIG. 5 is a view for explaining a third embodiment of a vortex chamber type combustion chamber of a diesel engine according to the present invention, and FIG.
(A) is a diagram for schematically explaining the inflow of the main flux and the sub-flux in the vortex chamber, and FIG. 5 (B) is an external view of the vortex chamber base viewed from the main combustion chamber.

FIG. 6 is a longitudinal sectional view of a vortex chamber type combustion chamber of a conventional diesel engine.

[Explanation of symbols]

2 ... Cylinder head, 4 ... Main combustion chamber, 5 ... Swirl chamber, 5a ...
8: injection hole, 10: main flux, 11: guide groove,
11b: terminal area, 11c: groove bottom, 22: oval sphere, 27
... Injection hole left side wall, 28 ... Injection hole right side wall, 35 ... Circular arc.

Claims (2)

[Claims] A vortex chamber (5) is provided in a cylinder head (2) of a diesel engine, and the vortex chamber (5) communicates with a main combustion chamber (4) through an injection hole (8) to form a main combustion chamber (5). The air of (4) flows into the vortex chamber (5) from the injection hole (8) into the vortex main flow (10).
In a vortex chamber type combustion chamber of a diesel engine configured to flow into the vortex chamber, a guide groove (11) is formed in the vortex chamber peripheral surface (5a) along the flow direction of the main flux (10). The inner groove (11c) of the terminal area (11b) of the guide groove (11) is formed so as to become shallower toward the terminal end, and the guide groove (11) is formed.
A vortex chamber combustion chamber of a diesel engine, characterized in that the flux (15) guided by (1) is deflected toward the center of the vortex chamber (5). 2. A vortex chamber (5) is provided in a cylinder head (2) of a diesel engine, and the vortex chamber (5) communicates with a main combustion chamber (4) through an injection hole (8). The air of 4) flows from the injection hole (8) into the vortex chamber (5) into the vortex main flow (31).
In the vortex chamber type combustion chamber of a diesel engine configured to flow into the vortex chamber (5), the injection hole wall (28) on the side where air first flows into the vortex chamber (5) from the injection hole (8) is formed into a predetermined basic shape ( 35) and by forming the injection hole wall surface (27) on the opposite side of the injection hole (8) according to the flat basic shape (22) which is flatter than the predetermined basic shape (35). A swirl chamber type combustion chamber for a diesel engine, characterized in that the height position of the injection hole wall surface (27) on the side is set higher than the injection hole wall surface (28) on the side where air first flows in.