JPS6113707Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an improvement to a nozzle for a pre-chamber of a diesel engine.

For convenience, the main parts of the combustion chamber of a diesel engine equipped with this type of conventional mouthpiece will be explained with reference to FIGS. 1 and 2.

In the figure, 1 is the cylinder head, 2 is the combustion chamber of the cylinder, 3 is the piston, 4 is the auxiliary chamber formed in the cylinder head, 5 is the fuel injection valve, 6 is the plug, 7 is the base for the auxiliary chamber, and 8 is a press fit. part, 9 is the spout, 1
0 is an exhaust valve, 11 is an intake valve, and 15 is a cylinder liner.

The mouthpiece 7 is formed into a cup shape and is fitted into the auxiliary chamber 4 of the cylinder head via a press-fitting part 8 formed at the bottom of the outer peripheral surface. The nozzle 9 extends from an opening 9a in the center of the inner surface of the bottom wall of the mouthpiece 7 toward the combustion chamber, that is, inclined toward the peripheral wall, and has an opening 9b on the outer surface of the outer wall. The cross section is rectangular.

The temperature around the nozzle 9 becomes very high, especially in the direction of the nozzle, and the end of the cylinder head on the combustion chamber 2 side that contacts the press-fit part 8 around the nozzle of the nozzle expands inward into the combustion chamber 2 as shown in the figure. There is a drawback in that a protruding portion α is formed, and a crack β is generated from the protruding portion α, that is, the mouth of the nozzle, toward the spout, and similar cracks are sequentially generated inward.

The purpose of the present invention is to provide a sub-combustion chamber mouthpiece that can eliminate the above-mentioned drawbacks. In the sub-chamber mouthpiece of a diesel engine, which is disposed in a portion communicating with the sub-chamber of the diesel engine, the sub-chamber mouthpiece has a substantially cup-shaped shape consisting of a peripheral wall and a bottom wall, and the inner surface of the bottom wall. A nozzle opening that extends from the central portion toward the central portion of the cylinder liner and communicates with the outer surface of the bottom wall, a press-fitting portion that is formed on the outer wall surface of the circumferential wall and press-fitting into the cylinder head, and a lower periphery of the press-fitting portion. The gist of the present invention is to provide a mouthpiece for a pre-chamber of a diesel engine, in which only a portion of the end portion close to the opening of the outer surface of the bottom wall of the jet nozzle is provided with a chamfered portion cut out at a small angle with respect to the outer wall surface. .

According to the configuration of the present invention, by forming the chamfered portion on the outer wall surface of the auxiliary chamber mouthpiece, the cylinder head side is free from the crack β without forming the bulge α into the combustion chamber as in the conventional structure. It is possible to prevent this from occurring.

In addition, since the chamfer is formed only on the lower peripheral end of the press-fitting part of the sub-chamber mouthpiece that is close to the nozzle, the chamfered part is formed around the entire circumference of the press-fitting lower end of the mouthpiece for the sub-chamber. Compared to the structure thus formed, the press-fitting area of the auxiliary chamber mouthpiece into the cylinder head is larger, and the holding force of the auxiliary chamber mouthpiece is increased.

Furthermore, since no chamfer is formed around the entire circumference of the lower end of the press-fitting mouthpiece for the sub-chamber, combustion gas is prevented from escaping to the outside through the gap between the mouthpiece for the sub-chamber and the gasket, thereby reducing the cylinder pressure. , it is possible to eliminate problems such as deterioration of fuel efficiency.

Furthermore, since the chamfer is cut out at a small angle with respect to the outer wall surface of the auxiliary chamber mouthpiece, the air space between the cylinder head and the auxiliary chamber mouthpiece created by the chamfer can be reduced and the compression ratio can be reduced. It is possible to minimize the decrease in Therefore, deterioration in combustibility due to a decrease in compression ratio can be prevented.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view showing a combustion chamber equipped with an embodiment of the mouthpiece according to the present invention, and FIG. 2 is a cross-sectional view taken along line A-A in FIG.
FIG. 3 is a plan view showing a cross-sectional section taken along arrow B and a section taken along arrow B; In the figure, numerals 1 to 11 and 15 are those explained in the conventional example.

In the present invention, the end of the opening 9b on the lower surface of the bottom wall of the nozzle 9 on the combustion chamber 2 side, that is, the end on the lower surface side of the bottom wall of the outer wall surface of the nozzle opposite to the edge 9c of the peripheral wall side of the opening 9b, is connected to the subchamber of the cylinder head. This is because the chamfer 12 is chamfered so as to escape from the inner circumferential surface of 4. This portion is indicated by the hatched area 12 in FIG.

The functions and effects of the above configuration will be described.

By providing the chamfered portion 12 described above, there is no need to form a bulge α into the combustion chamber 2 on the cylinder head side as in the conventional case, and there is an effect that the crack β which conventionally occurs can be prevented. Furthermore, the chamfered portion 12 can be manufactured together with the interior of the sub-chamber during casting.

In addition, since the chamfered portion 12 is formed only in the lower circumferential end of the press-fitting part of the sub-chamber mouthpiece 7 in a portion close to the opening 9b on the outer surface of the bottom wall of the spout 9, the press-fitting part of the sub-chamber mouthpiece 7 Compared to a structure in which a chamfered portion is formed over the entire circumference of the lower end, the press-fitting area of the sub-chamber mouthpiece 7 into the cylinder head 1 is increased, and the holding force of the sub-chamber mouthpiece 7 is increased.

Furthermore, in the configuration of the present application, since a chamfer is not formed around the entire circumference of the lower end of the press-fitting mouthpiece 7 for the sub-chamber, combustion gas can be prevented from escaping from the gap between the mouthpiece for the sub-chamber and the gasket. decrease in internal pressure,
Problems such as deterioration of fuel efficiency can be resolved.

Furthermore, since the chamfered portion 12 is cut out at a small angle with respect to the outer wall surface of the sub-chamber mouthpiece 7, the air space between the cylinder head 1 and the sub-chamber mouthpiece 7 created by the chamfered portion 12 is can be made small, and the drop in the actual compression ratio can be made extremely small. Therefore, it is possible to prevent deterioration of combustibility due to a reduction in the actual compression ratio.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a combustion chamber equipped with an auxiliary chamber mouthpiece according to an embodiment of the present invention, and FIG. 2 is a plan view showing a sectional area taken along the line A-A and an arrow B in FIG. 1. be. 1... Cylinder head, 2... Combustion chamber, 3...
Piston, 4...Subchamber, 7...Socket for subchamber, 8...
. . . Press-fitting portion, 9 . . . Nozzle port, 9a .

Claims (1)

[Scope of utility model registration request] For use in diesel engine sub-chambers located in the part that communicates the main combustion chamber with the diesel engine sub-chamber, which is located in the cylinder head radially outward of the cylinder liner from the cylinder liner extension line. In the cap, the cap for the sub-chamber has a substantially cup-shaped shape consisting of a peripheral wall and a bottom wall,
A nozzle opening extending obliquely from the center of the inner surface of the bottom wall toward the center of the cylinder liner and communicating with the outer surface of the bottom wall; and a press-fitting portion formed on the outer wall surface of the peripheral wall and press-fitted into the cylinder head. A sub-diesel engine characterized in that only a portion of the lower circumferential end of the press-fitting portion that is close to the opening of the outer surface of the bottom wall of the jet nozzle is provided with a chamfered portion cut out at a small angle with respect to the outer wall surface. Room cap.