JPH0211819A - Combustion chamber of internal combustion engine - Google Patents

Abstract

PURPOSE:To reduce the inflow loss of intake and secure the high intake charging rate by forming the wall surface of a combustion chamber between the valve ports corresponding to each intake valve into flat surface and forming the wall surface of other combustion chamber on the periphery of each valve port into conical form from the both edge parts of a valve seat. CONSTITUTION:Between intake valve ports 17a and 17b and between exhaust valve ports 18a and 18b, each wall surface 21, 22 of a combustion chamber 10 is formed into flat surface form extending from the corresponding opened port surfaces so as to be continuous to the opened port surfaces of the corresponding valve ports 17a, 17b, 18a, and 18b. While, each wall surface 23a, 23b, 24a, 24b of the combustion chamber 10 on the periphery of the intake valve ports 17a, 17b and exhaust valve ports 18a, 18b except the walls surfaces 21 and 22 is formed into conical form extending from the corresponding seat surfaces 25 and 26 so as to be continuous to the seat surfaces 25 and 26 of the valve seats 19 and 20 of the corresponding valve ports 17a, 17b, 18a and 18b. Therefore, the intake directed to the outward periphery of the intake valve ports 17a and 17b is smoothly introduced without generating an eddy current since each wall surface 23a, 23b on the periphery forms the conical plane extended from the seat surface 25.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a combustion chamber of an internal combustion engine.

(Prior Art and Problems to be Solved by the Invention) Internal combustion engines are known that are equipped with a plurality of intake and exhaust valves in order to improve output performance, etc., and the combustion chamber of such an internal combustion engine is Generally, a hemispherical combustion chamber is used, which makes it easy to arrange the valves.

However, when a hemispherical combustion chamber is used in such an internal combustion engine, depending on the wall shape of the combustion chamber, the intake air from the intake valve may not flow smoothly into the combustion chamber, which may adversely affect the intake air filling rate. .

The hemispherical combustion chamber 1 shown in FIG.
The wall surface of the combustion chamber around the valve 3 is formed in a hemispherical shape centered on the axis of the intake valve 2. -2
(Refer to Japanese Patent No. 1203), such a shape provides resistance to the intake air flowing in from the intake valve 2 regardless of the radius of the hemispherical surface.

That is, when the radius of the hemispherical surface is set to R1 so that the combustion chamber wall surface is in contact with the seat surface 5 of the valve seat 4, the intake valve 2
The intake air flows into the valve seat 4 at an angle θ of the seat surface, but the inflow angle θ is changed by the wall surface as shown in FIG.
As a result, a vortex of incoming intake air is generated on the intake valve 2 side, resulting in a loss.

Also, when the radius of the hemisphere is set to R, which is larger than R2, the wall angle θ2 is greater than the inflow angle θ, as shown in Figure 7.
becomes larger, and as a result, a vortex of incoming intake air is generated on the wall side, which also results in loss. In this case, the wall surface at the center of the combustion chamber where the ignition plug is arranged has four groove-like parts, so fuel tends to concentrate and the ignition plug tends to smolder.

Therefore, in such a hemispherical combustion chamber, there is a problem in that the intake air filling rate decreases due to loss when intake air flows in, and sufficient output performance cannot be obtained.

In addition, with such a hemispherical combustion chamber, the structure becomes more complicated as the number of intake valves and the like increases, and there is also the problem that manufacturability deteriorates.

This invention aims to solve these problems.

(Means for Solving the Problems) This invention provides, in a combustion chamber of an internal combustion engine having a plurality of intake valves, a wall surface of the combustion chamber between each valve port corresponding to each intake valve, from the end of the opening surface of the valve port. The other combustion chamber wall surface around each valve port is formed as a conical surface from the end of the valve seat surface of the valve port.

(Operation) Therefore, the intake air from each intake valve flows smoothly along the conical wall surface of the combustion chamber connected to the valve seat surface of each valve port, and no loss occurs. In addition, although the intake air also flows toward the opening of each valve port, the flow on the surrounding conical wall side becomes the main flow, so that the loss along the planar wall surface between each valve port becomes small.

(Embodiment) FIGS. 1 to 4 show an embodiment of the present invention, in which 10 is a combustion chamber, 11 is a sill head forming the combustion chamber 10,
12 is a shilling block, 13 is a piston, and 14 is a spark plug.

The combustion chamber 10 includes an intake valve port 17a that communicates with an intake port 15 and an exhaust port 16 formed in the Schilling Rad 11;
17b and exhaust valve ports 18a, 18b are opened in parallel with each other in a state inclined at a predetermined angle with respect to the central axis of the combustion chamber 10, and the intake valve port 17a.

17b and the exhaust valve ports 18a and 18b have suction and exhaust valves (not shown).
The valve seats 19 and 20 on which the exhaust valves are seated are respectively fitted.

Between the intake valve ports 17a and 17b and the exhaust valve port 1
8a and 18b, the wall surface 21 of the combustion chamber 10, respectively.
．． 22 are corresponding valve ports 17a and 17b.

It is formed in a planar shape extending from each corresponding opening surface so as to be continuous with the opening surfaces of 18a and 18b.

On the other hand, the intake valve ports 17a, 1 excluding the wall surfaces 21 and 22
7b and the combustion chamber 10 around the exhaust valve ports 18a, 18b.
The wall surfaces 23a, 23b, 24a, and 24b (striped portions in FIG. 3) correspond to the respective valve ports 17a.

Each corresponding seat surface 2 is continuous with the seat surface 25.26 of the valve seat 19.20 of 17b, 18a, 18b.
It is formed into a conical shape extending from 5.26. In this embodiment, the angle θ1 between the seat surface 25 and the intake valve center line 01 is the same as the angle θ2 between the wall surfaces 23a and 23b and the intake valve center line 02, but θ may be slightly larger than θ2. It may be slightly smaller.

Similarly, in this embodiment, the angle θ3 between the seat surface 26 and the exhaust valve center line 02 is the same as the angle θ4 between the wall surfaces 24a, 24b and the exhaust valve center line 02; It may be a little larger or a little smaller.

Note that the boundary 27 between the wall surfaces 23a and 24g and the wall surface 23
The boundary portion 28 between b and 24b has a protruding mountain shape, but in this case, the wall surface 29 of the inner combustion chamber 10 surrounded by the planar wall surfaces 21 and 22 may be formed of a smooth curved surface. good.

Also, on both sides of the walls 21.22, the shilling head 11
The end surfaces 30 and 31 of the holder are formed so as to protrude in an arc shape.

With such a configuration, the intake air from the intake port 15 is
When the intake valve opens, the intake valve ports 17a, 17b# flow into the combustion chamber 10 at the angle of the seat surface 25 of the valve seat 19.
At this time, the intake air directed toward the outer periphery of the intake valve ports 17a and 17b flows through the surrounding wall surface 23a.

23b are conical surfaces extending from the sheet surface 25, so that the conical wall surfaces 23a,
23b, it flows smoothly.

Furthermore, when a plurality of intake valve ports 17a and 17b are provided in this way, the flow of intake air toward the outer periphery of these ports becomes the mainstream, and most of the intake air flows through the surrounding conical wall surfaces 23a and 23.
It flows along b. Therefore, the intake air is
, 17b, but since the amount of intake air is small, the inflow resistance is small even if the wall surfaces 21 of the intake valve ports 17a, 17b are flat.

Furthermore, when the exhaust valve is opened, the exhaust gas that has finished combustion in the combustion chamber 10 is transferred to the conical wall surface 2 around the exhaust valve ports 18a and 18b.
4a, 24b and the exhaust valve port 1 along the planar wall surface 22.
8a, 18b to the exhaust boat 16 smoothly.

Therefore, intake air inflow loss is significantly reduced, and a good exhaust effect is obtained, thereby ensuring a high intake air filling rate and ensuring sufficient output performance of an internal combustion engine equipped with a plurality of intake valves.

Further, since the open wall surfaces 21 and 22 of each of the valve ports 17a and 17b and 18a and 18b are formed as flat surfaces, the structure is simplified and the manufacturability is improved.

In addition, the wall surface 2 of the combustion chamber 10 where the ignition plug 14 is arranged
Since 9 has a convex shape, the ignition plug 14 is caused by concentration of fuel.
It never smolders.

It goes without saying that this embodiment can also be applied to an internal combustion engine having three or more intake and exhaust valves.

(Effects of the Invention) As described above, according to the present invention, in a combustion chamber of an internal combustion engine including a plurality of intake valves, the wall surface of the combustion chamber between the valve ports corresponding to each intake valve is connected to the opening surface end of the valve ports. The other combustion chamber wall surface around each valve port is formed as a conical surface from the end of the valve seat surface of the valve port, simplifying the structure and reducing intake air inflow loss. A high intake air filling rate can be ensured, and a combustion chamber suitable for an internal combustion engine equipped with a plurality of intake valves can be provided.

[Brief explanation of the drawing]

Figures 1 to 4 are a plan view, a sectional view taken along the line A-A, a schematic perspective view, and a partial sectional view of a combustion chamber showing an embodiment of the present invention, and Figures 5 to 7 are of a conventional example. It is an explanatory diagram. 17a, 17b...Intake valve port, 19...Valve seat,
21...Wall surface, 23a, 23b...-Wall surface, 25...
- Seat surface. Patent applicant Nissan Motor Co., Ltd.

Claims (1)

[Claims] 1. In a combustion chamber of an internal combustion engine equipped with a plurality of intake valves, the combustion chamber wall surface between each valve port corresponding to each intake valve is formed in a plane from the end of the opening surface of the valve port, and A combustion chamber for an internal combustion engine, characterized in that a wall surface of the combustion chamber is formed from a conical surface from an end of a valve seat surface of a valve port.