JPH04330323A - Swirl chamber type combustion chamber - Google Patents

Abstract

PURPOSE:To correct a flow so as to prevent a secondary swirl or stagnation from being generated in an atomized flow inside of a swirl chamber type combustion chamber for a diesel engine, and restrain production of smoke. CONSTITUTION:In a swirl chamber 10 comprising an upper chamber 1 and a lower chamber 2, a rib 13 is projected in such a manner that the edge line 14 thereof extends in the direction of a connecting port 4 between the lover chamber 2 and a main combustion chamber 5 on an inner wall surface 7 of the lower chamber as a colliding surface of a main stream F of an injection flow injected into the swirl chamber 10 in a position 6 opposite to an injection port 3 of a fuel injection valve.

Description

[Detailed description of the invention]

0001

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

0002

2. Description of the Related Art An example of an overall view of a swirl chamber type combustion chamber of a conventional diesel engine is shown in FIGS. 3(a) and 3(b). Figure 3
As shown in (a), the swirl chamber type combustion chamber is located in the upper chamber 1.
The upper chamber 1 has a substantially hemispherical shape, the lower chamber 2 has a cylindrical or truncated conical shape, and the upper chamber is injected into the swirl chamber 10 from the injection valve nozzle position 3 that is open at the top. After the main stream F of the spray collides with the opposing surface 6 of the nozzle 3 on the wall of the vortex chamber, it generates a swirl flow S as shown by the arrow, mixes with air in the vortex chamber, and then enters the engine's main combustion through the communication port 4. Combustion gas is ejected into the chamber 5 to perform a fuel stroke, and power is transmitted to the crankshaft via the piston.

0003

[Problems to be Solved by the Invention] In the above structure, the spray that reaches the inner wall of the lower chamber 2 generates a swirl flow S and flows, reaching the bottom of the lower chamber 2, and a part of the spray reaches the bottom as indicated by the arrow Sc in the figure. It goes around in the circumferential direction like this,
A part of the fuel flows in the radial direction at the bottom as shown by the arrow Sd (FIG. 3(b)), reaches the communication port 4, and then flows out from there into the main combustion chamber 5. During this process, when the spray separates at the bottom of the lower chamber 2, secondary vortices and stagnation are generated as shown by the arrows in Figure 3(b), which sufficiently promotes the mixing of fuel and air. However, there is a problem in that incomplete combustion occurs and smoke is more likely to occur.

In order to solve the above problem, the present invention provides a swirl chamber type combustion chamber having a structure in which the flow is well rectified so that no secondary swirl or stagnation occurs in the spray flow flowing inside the swirl chamber 10. The purpose is to suppress smoke generation by providing

[0005]

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a vortex flow chamber having a vortex chamber consisting of an upper chamber equipped with a fuel injection valve and a lower chamber having a communication port with a main combustion chamber. In the indoor diesel engine, a vertical rib is protrudingly provided on the inner wall surface of the lower chamber at a position opposite to the injection port of the fuel injection valve, which is a collision surface of the main stream of the spray flow injected into the swirl chamber, and the rib provides a swirl chamber type combustion chamber for a diesel engine, characterized in that the ridge line is arranged so as to extend in the direction of the communication port.

[0006]

[Operation] When fuel is injected into the swirl chamber from the injection valve nozzle in the swirl chamber, the fuel spray hits a rib formed on the inner wall of the lower chamber on the opposite surface of the nozzle, where the spray is split into left and right sides. The mixed gas flows from the vortex chamber through the communication port and flows out into the main combustion chamber of the engine.

[0007]

[Embodiment] An embodiment of the present invention will be explained based on the drawings. The embodiment is shown in FIGS. 1 and 2, and the same parts as in FIG. 3 described above are given the same numbers and detailed explanations are omitted.

FIG. 1 shows an overall diagram of the shape of the swirl chamber type combustion chamber, in which 1 is the upper chamber, 2 is the lower chamber, 3 is the position of the injection valve nozzle, and 4 is the flow from the swirl chamber 10 to the main combustion chamber 5 of the engine. A communication port 6 for the spray flow is a surface facing the nozzle 3 on the wall of the vortex chamber, with which the main stream of the spray injected from the nozzle 3 first collides.

The inner surface 7 and the dish-shaped bottom surface 8 of the lower chamber 2
A rib is provided in a protruding shape extending from the lower part of the opposing surface 6 to the bottom surface 8 of the vortex chamber toward the direction of the nozzle 3, surrounding the inner wall portion 9 forming an R-shape at the boundary with the r
ib) 13 is formed in the vertical direction on the inner wall surface 7 of the lower chamber 2. The ridgeline 14 of this rib 13 extends in the direction of the communication port 4, and its shape is similar to the cross-sectional view of the rib 13 in FIG.
As shown in C)), the root portion 15 of the rib 13 has a gently rounded shape so that the spray flow that hits the rib is smoothly divided.

[0010] With the above configuration, the spray stream injected from the nozzle 3 of the upper chamber 1 hits the opposing surface 6 of the nozzle, where it is divided into right and left by the ribs 13 and circulates around the bottom of the lower chamber 2. At this time, the ribs act as guide plates for the spray flow,
Since the spray stream is rectified, the branched spray streams reach the communication port 4 without interfering with each other as shown by the arrows in FIG. 2(a). Furthermore, the rib 13 also functions to ensure that the spray flows smoothly and does not stagnate due to the rounded shape of the root portion 15 of the rib.

[0011] Through the above process, the spray flow is well rectified,
Flow interference and secondary vortices are no longer generated.

0012

[Effects of the Invention] By implementing the present invention, the following effects can be achieved. In other words, by providing ribs on the inner wall surface of the lower chamber of the combustion chamber of the swirl chamber, the spray flow inside the swirl chamber is well rectified, eliminating flow interference, stagnation, and the generation of secondary vortices, and improving the mixing of fuel and air. is sufficiently promoted, good combustion conditions are obtained, and smoke generation is suppressed.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing the entire swirl chamber type combustion chamber according to an embodiment of the present invention.

FIG. 2(a) is a cross-sectional plan view of the swirl chamber type combustion chamber shown in FIG. 1, FIG. 2(b) is a BB sectional view of FIG. 2(a), and FIG. 2(C) is a diagram 2(b) is a cross-sectional view taken along line CC of the rib portion shown in FIG.

FIG. 3(a) is a perspective view showing the entire swirl type combustion chamber according to the prior art, and FIG. 3(b) is a cross-sectional plan view of FIG. 3(a).

[Explanation of symbols]

1...Upper chamber 2...Lower chamber 3...Injection valve nozzle 4... Contact point 5...Main combustion chamber 6... Opposite surface of the spout 10... Vortex chamber 13...Rib 14... Rib ridgeline

Claims (1)

[Claims] 1. In a swirl chamber type diesel engine having a swirl chamber consisting of an upper chamber equipped with a fuel injection valve and a lower chamber having a communication port with a main combustion chamber, the fuel is injected into the swirl chamber from an inner wall surface of the lower chamber. A vertical rib is provided in a protruding position at a position opposite to the nozzle of the fuel injection valve, which is a collision surface of the main stream of the spray stream, and the rib is arranged so that its ridgeline extends in the direction of the communication port. A swirl chamber type combustion chamber for a diesel engine is characterized by: