JPS59141717A - Piston for use in internal-combustion engine - Google Patents

Abstract

PURPOSE:To prevent quenching of flame, by forming cavities in the inner surface of an open chamber type combustion chamber at the positions thereof corresponding to holes of a fuel injection nozzle, and forming a pocket at a particular position of each cavity. CONSTITUTION:A combustion chamber 12 consisting of a round recess is formed at the top 11 of a piston 10 substantially at the central portion of the same. The same number of cavities 14 as the number of holes of a fuel injection nozzle 13 are formed in the inner surface of the combustion chamber 12 in the manner that they oppose the holes of the injection nozzle 13. Further, a pocket 16 is formed in each cavity 14 at the position thereof located on the upstream side of circumferential swirl 15. With such an arrangement, micro-swirls 21 are produced by the cavities 14 each having a pocket 16, so that mixing of fuel and intake air is promoted. Further, quenching of flame is prevented by the flame flow along the surfaces of the cavities 14.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a piston for an internal combustion engine, and more particularly to a piston having an oven chamber type combustion chamber in 16 parts.

In a direct-injection diesel engine, fuel is injected from a fuel injection nozzle toward a combustion chamber formed at the top of a piston, and combustion explosion occurs within the combustion chamber to obtain output. That is, for example, as shown in FIG. 1, an open chamber type combustion chamber 2 is formed at the top of a piston 1, and fuel is injected onto the inner surface of this combustion chamber 2 to cause a combustion explosion. However, the flame generated in the combustion chamber 2 moves in the direction C1 along the surface of the combustion chamber 2 as shown by the arrow 3 in FIG.
Flows toward the top side. And piston 1 l711? ; Since the flame is quenched in the lower temperature part, the flame is extinguished here, resulting in incomplete combustion.

In other words, an open chamber type fuel 1 as shown in FIG.
If a piston 1 with two chambers 2 is used, the carbon content in the exhaust gas will increase, resulting in black smoke 11 being emitted.

In order to avoid such drawbacks of the open chamber type combustion chamber, a screw engine 1 equipped with an end runt type combustion chamber 4 as shown in FIG. 2 has been used. By forming a squish lip 5 on the opening edge of the combustion chamber 4, the amount of flame ejected to the top of the piston 1 is reduced.
・The squish lip 5 that forms the opening edge of the combustion chamber 4 (the flesh 11 at its tip) Since it is exposed to high heat loads, it is prone to cracking, which reduces reliability.
That will happen.

The present invention has been made in view of these problems, and aims to provide a highly reliable piston that prevents flame quenching. An example will be explained.

3 and 4 show a piston 10 according to this embodiment, and a combustion chamber 12 consisting of a circular recess is formed approximately at the center of the top 11 of the piston 10. has been done. This combustion chamber 12 is basically an oven chamber type. On the inner surface of this combustion chamber 12, four parts 14 are formed, the same number of which corresponds to the nozzles of the combustion nozzle 13. As shown in FIG. 5, the cross-sectional shape of the four portions 14 in the height direction is deeper at the upper end to form a bulge 1-22. On the other hand, the lower side is formed by a gentle curve and is almost continuous with the single part of the combustion chamber 12.

The upper end of the fourth part 14 (J) is lower on the downstream side of the swirl 15 than on the eleventh stream side. Also, the cross-sectional shape of the fourth part 14 in the circumferential direction is as shown in FIG. It is asymmetrical with respect to f-) swirl 15
The upstream side of the pocket is deeper, and this portion constitutes the pocket 16. Further, at the top of this piston 10, a relief is formed by a fourth part 17.1B to escape a pair of valves.

In the above-described configuration, the combustion chamber 1 of the piston 10
The fuel injected from the nozzle of the fuel injection nozzle 13, which is arranged at a position that corresponds approximately to the medium flame part 2, is injected toward the recess 14 of the combustion chamber 12, as shown by the arrow 19 at a3 in FIG. will be done. Then, due to the high temperature in the combustion chamber 12, it is ignited and combustion does not occur. The flame during this combustion is transmitted to the recess 14 as shown by the arrow 20 in FIG.
It will rise along the wall. Since the upper end of the wall surface of the fourth part 14 is deeply recessed by the bore 22, the shape of the wall surface of the fourth part 14 allows the flame 20 to be directed back to the inner part 11 of the combustion chamber 12. 1′
Ru.

Therefore, due to these four parts 14, the amount of flame 1j1 emitted to the upper side of the piston 10 is reduced. Therefore, the amount of fuel that is quenched on the outer circumferential side t of the top 11 of the piston 10 is also reduced. This makes it possible to reduce the amount of black smoke in the exhaust gas. Furthermore, the flame indicated by the arrow 20 in FIG. 5 is interfered with by the swirl 15 flowing in the circumferential direction on the inner surface of the combustion chamber 12, so that the mixing ratio with the intake air is increased and the combustion is further accelerated. Serve what is done to you.

Further, according to the screws 1 to 10 according to the seventh embodiment, the recess 141 formed on the inner surface of the combustion chamber 12 has a deep pocket 16 on the upstream side with respect to the flow of the seven swirls 15. Please refer to Figure 6 for this four part] 4
It becomes possible to generate micro-swirls 21 within. The lever microswirl 21 causes the ffa content of the atomized fuel and air to be decimalized, thereby making it possible to achieve more complete combustion.

However, this microphone [1 swirl 21] is generated more effectively because the pocket 16 is placed on the Q side (IQ G) of the scanner 15.

As described above, if the screw 1 according to this embodiment is used, the four parts 14 are provided on the inner surface of the combustion chamber 12. Due to this, the flame 20 flows onto the wall surface of this recess 14,
At the same time, combustion is promoted by intersecting the swirl 15, and quenching is prevented by preventing the flow from flowing radially outward over the top 11 of the piston 1°. 11th ability and t3. Therefore Jl
It becomes possible to reduce black smoke in the 1-air gas. Moreover, pockets 1 to 16 are arranged in the fourth part 14, and the existence of this pocket 16 is due to this micro-swirl 21 in order to effectively generate the micro-swirl 21. This further promotes the mixing of fuel and intake air, making it possible to perform targeted combustion. Moreover, this combustion v12 is basically 1. Since it is configured in an east oven chamber type and no skiff lip is formed on the opening edge, it is possible to obtain a highly reliable piston 10.

As mentioned above, the present invention forms four parts on the inner surface of the combustion chamber at positions corresponding to the injection nozzle [1], and upstream of the nozzles in the circumferential direction of these four parts. It is designed with a pocket 1~ installed on the side. Therefore, according to the present invention, a micro-swirl is generated by the concave portion of the pocket, which further promotes the mixing of the fuel and the intake air, and prevents the flame flow along the four parts from occurring. It is possible to do 11; It is also necessary to set up a squish lip.
! This makes it possible to provide highly reliable services for customers.

[Brief explanation of the drawing]

Figure 1 is a vertical cross-sectional view of a piston with a combustion chamber of a conventional engine 11 chamber Qlj, Figure 2 is a longitudinal sectional view of a piston equipped with a combustion chamber of a conventional engine
・Longitudinal cross-sectional view of a piston with a run I-type combustion chamber II,
FIG. 3 is a plan view of the screws 1 to 1 according to an embodiment of the present invention, FIG. 4 is a sectional view taken along the line ■ to ■ in FIG. 3, and FIG. 5 is a sectional view taken along the line V to V in FIG. 3. , Figure 6 is d-3 in Figure 5.
This is a cross-sectional view taken along lines V1 to V. In the codes used on page 1 of the 1st page, 10...Bis 1-11...Top 12...Combustion dormitory 13...Moon II llFm nozzle 14...Four parts 15...Swirl 16 ...It's blurry.

Claims (1)

[Claims] I! has an oven chamber type combustion chamber on the top! 9( ), the inner surface of the combustion chamber has a fuel f11
For an internal combustion engine, a recess is formed in each hole W corresponding to the nozzle of the 11A injection nozzle, and a pocket is provided on the upstream side of the swirl in the circumferential direction of the recess. piston.