JP2686360B2 - Subcombustion chamber of internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a sub-combustion chamber of an internal combustion engine.

[Conventional technology]

FIG. 3 shows a sub chamber combustion chamber of a conventional internal combustion engine. In the figure, a main chamber 11 is provided above the piston 10, and the main chamber 11 is provided.
11 and the upper part 20 of the sub chamber are communicated with each other via the lower part 21 of the sub chamber and the nozzles 22 and 23. A fuel injection nozzle is provided in the upper part 20 of the sub chamber.
30 is provided to inject fuel into the upper portion 20 of the sub chamber.

[Problems to be solved by the invention]

However, in such a conventional example, since the injection pressure of the fuel injected from the fuel injection nozzle 30 to the sub chamber upper portion 20 is reduced when the engine rotation speed is reduced, the air in the sub chamber upper portion 20 is not sufficiently mixed, Inadequate combustion results in increased smoke density. Especially when the engine speed is low and the load is low, the amount of fuel injected into the upper part 20 of the sub chamber decreases, and the heat generation and combustion pressure in the sub chamber decrease. The outflow rate to the main chamber 11 decreases, mixing with the air in the main chamber 11 and the subsequent combustion become insufficient, leading to an increase in smoke concentration.

The object of the present invention is to solve the problems of the conventional device, promote the mixing of fuel and air in the sub-chamber even at low rotation speed and low load, improve combustion, suppress increase in smoke concentration, and improve engine performance. An improved combustion chamber of the internal combustion engine is provided.

[Means for solving the problem]

A sub-chamber combustion chamber of an internal combustion engine of the present invention is a sub-chamber combustion chamber of an internal combustion engine having a sub-chamber lower portion communicating with the main chamber via an injection port and a sub-chamber upper portion having a diameter larger than the sub-chamber lower portion. A plurality of lower sub-chambers are provided for one upper sub-chamber, and the projection lines of the center lines of the lower sub-chambers on the II-II cross section are substantially parallel to each other, and It is characterized in that the lower part of each sub chamber is inclined in the swirling direction.

[Action]

As described above, according to the present invention, a plurality of sub-chamber lower portions are provided for one sub-chamber upper portion, and each sub-chamber lower portion is inclined in the direction of the swirl flow. A flow of a swirl component perpendicular to the direction is generated, and mixed combustion with air is promoted in the peripheral portion of the fuel spray.

Further, the small-diameter injection port that communicates the lower portion of the sub chamber with the main chamber enhances the dispersibility of the jet flow in the main chamber and promotes combustion in the main chamber.

As a result, even when the engine is running at a low speed and the fuel injection pressure is low, the fuel and air are sufficiently mixed, good combustion is obtained, and an increase in smoke concentration can be suppressed.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 is a sectional view of the essential parts of the first embodiment, and FIG. 2 is a sectional view of FIG.
It is II-II sectional drawing.

In FIGS. 1 and 2, 11 is a main chamber formed in the upper part of the piston 10, and 50 is a sub chamber mouthpiece 50 fixed to the cylinder head. The tip of the sub-chamber cap 50 projects into the main chamber 11 as shown in FIG. In the sub-chamber base 50, one large-diameter sub-chamber upper portion 20 is formed on the upper portion thereof, and two (or a plurality of) sub-chamber lower portions 41, 42 communicate with the lower side of the sub-chamber upper portion 20. Is provided.

The tips of the lower parts 41 and 42 of the sub chambers are
Is communicated with the main chamber 11 via. Lower part of each sub chamber
As shown in FIG. 1, the reference numerals 41 and 42 incline in the direction of the entire inflow from the main chamber 11 to the sub chamber upper portion 20, that is, in the directions opposite to each other with respect to the center line a of the sub chamber upper portion 20, and the II-II cross section. The projection lines above are substantially parallel as shown in FIG.

Therefore, the two sub chamber lower parts 41 and 42 are provided so as to be inclined in the direction of the swirling flow in the sub chamber upper part 20.

In the sub-chamber combustion chamber configured as described above, air during the compression stroke flows from the main chamber 11 to the sub-chamber upper part 20 through the injection ports 22 and 23 and the sub-chamber lower parts 41 and 42, and in the sub-chamber upper part 20. A swirl flow in the direction of arrow b in FIG. 2 is generated. That is, according to such a configuration, a plurality of sub chamber lower parts 41 inclined in the direction of the swirl flow,
By 42, a flow of a swirl component perpendicular to the fuel injection direction is generated, and mixed combustion with air is promoted in the peripheral portion of the fuel spray.

Further, the small-diameter nozzles 22 and 23 that connect the sub-chamber lower portions 41 and 42 and the main chamber 11 enhance the dispersibility of the jet flow in the main chamber 11 and promote combustion in the main chamber 11.

As a result, even when the load is low, the mixing of fuel and air in the lower part 20 of the sub chamber is promoted, and good engine performance can be secured.

〔The invention's effect〕

Since the present invention is configured as described above, since a swirl flow is generated in the sub chamber (upper part, lower part) during the compression stroke, combustion in the sub chamber becomes good even at low rotation and low load.
Heat generation is large in the sub chamber, pressure also rises, and the outflow speed from the sub chamber to the main chamber is increased, so combustion in the main chamber is also improved,
The increase in smoke density is suppressed.

[Brief description of the drawings]

1 and 2 relate to the present invention, FIG. 1 is an overall configuration diagram of the first embodiment, FIG. 2 is a sectional view taken along line II-II of FIG. 1, and FIG. It is a figure. 11 ... Main chamber, 20 ... Sub chamber upper part, 41, 42 ... Sub chamber lower part, a ... Overall flow direction from main chamber to sub chamber.

Continuation of the front page (56) Bibliography Sho 56-159624 (JP, U) Steady flat 3-6022 (JP, U) Steady flat 3-145515 (JP, U) Japanese Patent Sho 32-6052 (JP , B1)

Claims (1)

(57) [Claims] 1. A sub-chamber combustion chamber of an internal combustion engine having a sub-chamber lower portion communicating with a main chamber via an injection port, and a sub-chamber upper portion having a larger diameter than the sub-chamber lower portion, wherein the sub-chamber lower portion is A plurality of sub-chambers are provided for each sub-chamber upper portion, and the projection lines of the center lines of the sub-chamber lower portions on the II-II cross section are substantially parallel to each other. A sub-chamber combustion chamber of an internal combustion engine, characterized by being inclined in a direction.