JPS5840256Y2 - combustion chamber of diesel engine - Google Patents

Description

[Detailed explanation of the idea] The present invention relates to an improvement in the combustion chamber of a diesel engine.

Conventionally, combustion in the combustion chamber of a direct injection diesel engine is carried out by injecting high-pressure fuel oil from a fuel injection pump into the wall of the combustion chamber located at the top of the piston using a fuel injection valve. The impinging fuel oil is reflected and diffused by the wall surface, and spreads throughout the combustion chamber formed by the lower surface of the cylinder head and the recessed portion of the top of the piston.

However, in the combustion chamber of a conventional direct injection diesel engine, the wall surface that the high-pressure injected fuel oil collides with is a concave or flat surface that is part of a circle or a spherical surface, so the reflected fuel oil is Since the fuel is mainly directed in the direction of the injector nozzle, the diffusion area of the fuel reflected by the combustion chamber wall is limited, while when the piston performs the compression stroke, air flows into the combustion chamber and creates a vortex flow. The mixing of the red-hot air in the swirling flow and the fuel oil reflected from the wall surface of the combustion chamber is limited, and there is a drawback that black smoke is generated due to poor combustion and incomplete combustion.

This has not only become a pollution problem in recent years, but has also been cited as a cause of increased fuel consumption.

Therefore, in order to eliminate the above-mentioned conventional drawbacks, the present invention actively promotes the diffusion of fuel reflected on the combustion chamber wall surface, thereby reducing the generation of black smoke due to incomplete combustion, and improving the combustion efficiency of the engine. The aim is to reduce fuel consumption by improving performance.

That is, in the present invention, in the combustion chamber of the piston, near the wall surface of the combustion chamber where the fuel oil injected from the fuel injection valve collides,
It consists of a combustion chamber of a diesel engine provided with a rough cast surface consisting of a large number of irregularities so that the colliding fuel is diffusely reflected at a reflection angle different from the incident angle.

Embodiments of the present invention will be described below based on the drawings.

Fig. 1 is a plan view of a piston combustion chamber in an embodiment of the present invention, Fig. 2 is a longitudinal sectional view of the combustion chamber portion in the above embodiment, and Fig. 3 is a diagram showing combustion in the above embodiment. FIG. 3 is a partially enlarged plan cross-sectional view of a main part of the wall of the chamber.

1 and 2, fuel oil injected from the fuel injection nozzle 1 is injected in the direction B shown in FIG. 1 and collides with the wall surface 7 of the combustion chamber 4 of the piston 6.

Therefore, in the present invention, the wall surface in the vicinity where the fuel oil collides is made into a rough casting surface 2, and the incident angle and the reflection angle of the injected fuel oil injected at high pressure are actively controlled by the uneven parts of this casting surface 2. This increases the fuel oil diffusion area and improves the fuel oil swirl flow (
(indicated by the flow direction S in FIG. 1).

That is, the high-pressure injected fuel oil injected from the fuel injection nozzle 1 in the combustion chamber 4 travels in the direction B shown in FIG. do.

As shown in Figure 3, some of the fuel oil is absorbed into the casting surface 2.
The wall surface 1 spreads like a film along the wall surface 7 which has been cut to prevent the swirl flow S from weakening.
The other part is a complicated reflected flow C, C' as shown in FIG.

and so on.

This reflected flow c, c', C! The first class forms a much wider diffusion region than the conventional diffusion region.

Furthermore, it has been confirmed through experiments that the casting surface 2 has rough irregularities of 200S or more and is suitable for the purpose of the present invention.

According to the present invention, a rough cast surface consisting of many irregularities is provided near the wall surface of the combustion chamber where the fuel oil injected from the fuel injection valve collides, so that the injection occurs due to the irregularities of the cast surface. By actively differentiating the angle of incidence of fuel oil and its reflection angle, the injected fuel oil can be reflected diffusely in complex directions away from the center of the combustion chamber, creating a significantly wider diffusion area. .

In addition, the unevenness of the casting surface creates a wide diffusion area, so
There is no reduction in the main swirl flow in the combustion chamber, and there is no attenuation of the main fuel injection flow due to collision with the reflected flow.

Therefore, since the injected fuel oil and air are actively mixed, a good air-fuel mixture is formed, thereby significantly improving the combustion performance of the engine and reducing fuel consumption.

Furthermore, since incomplete combustion is prevented, the generation of black smoke is also reduced.

Among these, the present invention is mainly effective for direct injection diesel engines.

[Brief explanation of drawings]

Fig. 1 is a plan view of the piston combustion chamber in the embodiment of the present invention, Fig. 2 is a longitudinal cross-sectional view of the combustion chamber portion in the above embodiment 1, and Fig. 3 is the combustion chamber in the above embodiment. FIG. 3 is a partially enlarged plan sectional view of the main part of the wall of the chamber. 2... Uneven surface, 3... Cylinder head, 4... Combustion chamber, 6... Piston, 7... Wall surface.

Claims (1)

[Scope of utility model registration request] In the combustion chamber of the piston, near the wall surface of the combustion chamber where the fuel oil injected from the fuel injection valve collides, there are many irregularities that cause the colliding fuel to be diffusely reflected at a reflection angle different from the angle of incidence. The combustion chamber of a diesel engine has a rough cast surface.