JPH0134659Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a swirl chamber installed in the cylinder head of a diesel engine.

Prior Art The swirl chamber of a conventional diesel engine consists of an upper hemispherical portion 20 formed in the cylinder head 1 itself, which is made of aluminum alloy or cast iron, as shown in FIG.
It generally consists of a lower hemispherical portion 22 that is formed separately from the cylinder head and is made of a heat-resistant metal and constitutes a lower chamber that is inserted from below the cylinder head. Although this type of swirl chamber is simple and inexpensive to manufacture, most of the wall of the swirl chamber is made up of the cylinder head itself, so the air, injected fuel, and combustion gas within the swirl chamber are directly connected to the cylinder head. There is a problem in that the inner wall surface is cooled and its heat retention is insufficient. Therefore, a type has been proposed in which the swirl chamber is constructed separately from the cylinder head and is inserted into a recess provided in the cylinder head. Among these types, there is one in which the vortex chamber has an integrated upper and lower structure (for example, see Japanese Patent Application Laid-Open No. 14827/1982), but this increases the casting cost and requires a large upper nozzle hole for casting. This is unfavorable in terms of combustion, and also has an adverse effect on the heat resistance of the nozzle.

In addition, the vortex chamber is divided into two parts (upper and lower parts) and welded to integrate them (for example,
135221), however, there is a problem in that distortion occurs due to welding and the fit is deteriorated when the swirl chamber is attached to the cylinder head.

Purpose of the invention The present invention was made in order to solve the above-mentioned problems of the swirl chamber of the conventional diesel engine, and its purpose is to Improves fitability and reduces welding distortion between the upper and lower swirl chambers, improves fitability to the cylinder head, improves heat retention of the swirl chamber, prevents smoke generation, and further improves fuel efficiency. The object of the present invention is to provide a swirl chamber for a diesel engine that can be used in a diesel engine.

Composition of the invention In order to achieve the above object, the present invention has a structure in which the swirl chamber is divided into two parts, an upper chamber and a lower chamber, and the upper end of the lower chamber and the lower end of the upper chamber are fitted together. , Spot welding is performed along the outer periphery of this fitting part, and a gasket is filled and sealed in the annular gap between the sealing surface on the outer periphery of the upper chamber and the cylinder head on the side of the upper chamber from this spot welding part to create a vortex flow. It is characterized by the fact that it is made up of a chamber.

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

FIG. 2 shows an embodiment of the present invention, in which a cylinder head 1 has a swirl chamber 2 assembled therein. As shown in FIG. 3a, the swirl chamber 2 consists of an upper chamber 21 and a lower chamber 22 made of a heat-resistant material such as a heat-resistant alloy. The upper end cylindrical outer peripheral part 25 is closely fitted in a lock-in style to form a vortex chamber as shown in FIG. Fixed and integrated. This spot welding is only required to prevent rotational deviation between the upper and lower chambers 21, 22, and three to four welding locations are sufficient.

The swirl chamber 2 integrated in this way is fitted into the cylinder head hole 11 formed in the cylinder head 1, and the sealing surface (shoulder) 23 on the outer periphery of the upper chamber 21 of the swirl chamber 2 is connected to the cylinder head hole. The annular gap 29 between the upper chamber 21 and the cylinder head 1 is filled with a gasket 3 and sealed.
Prevent combustion gas from leaking to the outer periphery of the lower chamber. This gasket 3 is preferably a steel plate gasket formed by bending a steel plate as shown in FIG. Reference numeral 28 denotes a gap between the outer cylindrical portion of the lower chamber 22 and the inner wall of the cylinder head hole 11, and the gasket 3 is installed to prevent combustion gas from flowing from the gap 29 to the gap 28. Note that the gap 29 must be provided due to dimensional tolerances when assembling the swirl chamber 2 and the cylinder head 1. When fitting the swirl chamber 2 into the cylinder head hole 11, the dowel pin 5 is inserted and fitted between the outer peripheral wall of the lower chamber 22 and the cylinder head hole 11 to position the swirl chamber 2.
This prevents rotational movement of the cylinder head 1 with respect to the cylinder head 1. 4 is an injection nozzle which is inserted into the upper chamber 2 as shown in the figure.
It communicates with 1. 12 is a fitting surface between the lower chamber 22 and the cylinder head hole 11, and 13 is the upper chamber 21.
Since both the fitting surfaces 12 and 13 have a coaxiality tolerance, the fitting surface 12 is usually an interference fit, and the fitting surface 13 is the fitting surface between the cylinder head hole 11 and the cylinder head hole 11.
The one is a gap fit.

A comparison in terms of performance between this embodiment having the above configuration and a conventional conventional swirl chamber is shown in FIG. The solid line shown in the figure represents the experimental results of this embodiment, and the broken line shown with 2 represents the experimental results of the conventional vortex chamber.

According to the figure, it can be seen that the heat retention effect of the vortex chamber 2 of this embodiment promotes mixing of fuel and air, and smoke and fuel consumption rate are reduced compared to the conventional example. The above-mentioned reduction effect is particularly remarkable in a high load range where the excess air ratio is small. There is a concern that the volumetric efficiency will decrease due to heat retention in the vortex chamber, but in this case, the heat retention is local and the degree of decrease in volumetric efficiency is extremely small and does not pose a problem.

Effects of the invention Since the invention has the above-mentioned configuration, the vortex chamber is configured separately from the cylinder head, which has a heat retention effect and promotes the mixing of fuel and air. As a result, both smoke generation and fuel consumption are significantly reduced, and since the upper and lower chambers are fitted in a seal type manner, the fit is good, making it easy to center the upper and lower chambers. Furthermore, since the upper and lower chambers are fixed by only spot welding, it is possible to reduce the distortion during welding that occurs in conventional continuous welding structures, and it is possible to reduce the distortion of the integrated vortex chamber to the cylinder head. Fitting performance is improved, so finishing work on the outer periphery of the swirl chamber after integration becomes unnecessary.

Furthermore, since the annular gap between the upper chamber of the swirl chamber and the inner wall of the cylinder head hole is filled and sealed with a gasket, wasted space is eliminated, gas leakage is prevented, and fuel consumption rate is prevented from deteriorating. Since the combustion gas does not reach the lower spot weld directly, there is an effect that the spot weld does not deteriorate due to heat.

[Brief explanation of drawings]

Fig. 1 is a vertical cross-sectional view of a conventional swirl chamber, Fig. 2 is an enlarged longitudinal cross-sectional view of an embodiment of the present invention, and Fig. 3 is an explanatory view showing the assembly process of the swirl chamber of the same embodiment. Fig. 4 is an enlarged sectional view showing the shape of the gasket in the above embodiment; Fig. 5 is the performance of the present invention and the conventional example. It is a graph showing the comparison of. 1... Cylinder head, 2... Vortex chamber, 21...
...Upper chamber, 22...Lower chamber, 23...Shoulder, 24
... Cylindrical inner peripheral part, 25 ... Cylindrical outer peripheral part, 26
...Spot welding, 3...Gasket, 4...Injection nozzle, 5...Knock pin.

Claims (1)

[Scope of utility model registration request] The swirl chamber to be provided in the cylinder head is divided into an upper chamber and a lower chamber, and the upper end of the lower chamber and the lower end of the upper chamber are fitted together, and spot welding is performed along the outer periphery of this fitting part. A swirl chamber for a diesel engine characterized in that an annular gap between a sealing surface on the outer periphery of the upper chamber and the cylinder head is filled and sealed with a gasket on the upper chamber side of the spot weld.