JPH07668Y2 - Intake port structure of internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to an intake port structure of an internal combustion engine in which three intake valves are provided for one cylinder.

[Conventional technology]

In order to improve the output performance of the engine, a configuration in which three intake valves are provided for one cylinder is conventionally known (Japanese Patent Laid-Open No. 60-216013). FIG. 1 (B) shows a state in which the intake port is viewed from the inlet opening 11 in such an engine, and is located at the upper part of the inner wall of the intake port and directly above the three outlet openings 12, 13, 14. Stem guides 15, 16 and 17 supporting each intake valve project downward. Further, the walls 18 and 19 which are the inner walls of the intake port and which are between the central outlet opening 13 and the outlet openings 12 and 14 on both sides have the shortest intervals between the outlet openings. Located in the part.

[Problems to be Solved by the Invention] In the intake port having the above-mentioned configuration, the air flowing in from the inlet opening 11 is, as shown in FIG.
It passes through the outlet openings 12, 13, 14 along the arrows C, D, E, respectively, and flows into the cylinder 22, that is, the combustion chamber. But,
The air flow passing through the outlet openings 12 and 14 on both sides impinges on the walls 18 and 19 between the outlet openings, which causes turbulence and a large resistance, and therefore, from the central outlet opening 13. Sufficient air flows into the combustion chamber, but exit openings 1 on both sides
There is a problem that the amount of air flowing in from 2, 14 becomes small, and the intake efficiency becomes insufficient as a whole.

An object of the present invention is to obtain an intake port structure that allows intake air to flow into the combustion chamber from each outlet opening without being greatly affected by the wall near the outlet opening, and to exhibit sufficient intake efficiency. And

[Means for Solving the Problems]

The intake port structure of an internal combustion engine according to the present invention is provided with three intake valves for one cylinder, and the intake port has three outlet openings and one inlet opening opened and closed by each intake valve, In the intake port structure of the internal combustion engine in which the stem guide that supports the valve stem of the intake valve is projected on the inner wall of the intake port, the inner wall portions that are substantially upright in the vicinity of the three outlet openings of the intake port have a central outlet opening. A first portion contacting a peripheral portion of the portion in a range facing a rear surface of the valve stem of the corresponding intake valve when viewed from the inlet opening portion, and a peripheral portion of another outlet opening portion from both sides of the first portion. And a second portion reaching the portion.

[Action]

The intake air flows into the combustion chamber through the outlet openings with almost no collision with the wall between the outlet openings. Therefore, the resistance of the intake air is reduced, and the intake efficiency is improved.

〔Example〕

 The present invention will be described below with reference to illustrated embodiments.

FIG. 2 shows an embodiment of the present invention. In this figure, a cylinder head 20 is formed with an intake port 10 extending obliquely with respect to an axis I of the cylinder, and a terminal portion of the intake port 10 with respect to an axis J of an upstream side portion of the intake port 10. A throat portion 10a having an axis K that is slightly inclined is formed. An annular valve seat 21 is fitted in the throat portion 10a. The present embodiment is a 5-valve engine, and one cylinder is provided with three intake valves and two exhaust valves. As shown in FIG. 3, the intake port has three outlet openings 12, 13, 14 opened and closed by each intake valve and one inlet opening 11. Stem guides 15, 16 and 17 that slidably support valve stems (not shown) of the intake valves project from the inner wall of the intake port.

FIG. 1 (A) shows a state in which the intake port is viewed from the inlet opening 11 side, and a valve stem (not shown) is provided on the inner wall surface of the central outlet opening 13 on the cylinder center side. A rectangular wall surface 31 having substantially the same width as that of is formed. In other words, this rectangular wall surface 31 is
It is in contact with the rear surface of the valve stem of the corresponding intake valve when viewed from 11 in a range facing the rear surface. The surface shape of the walls 18 and 19 which are the inner wall of the intake port and between the central outlet opening 13 and the outlet openings 12 and 14 on both sides extends from the end of the rectangular wall surface 31 to form the outlet openings on both sides. It is formed so as to be in contact with the peripheral portions of 12,14. The walls 18 and 19 in this embodiment
When the shape of is compared with the conventional example shown in FIG. 1 (B), conventionally, the surfaces of the walls 18 and 19 are the portions with the shortest distance between the outlet openings (the portion indicated by the symbol P in FIG. 1 (B). ), And has a structure projecting between the outlet openings 12, 13, 14, but according to the present embodiment, the walls 18, 19 are in a retracted position as compared with the prior art. There is almost no protrusion between the outlet openings 12, 13, 14.

The rectangular wall surface 31 having substantially the same width as the valve stem is formed in order to secure the strength performance of the cylinder head without increasing the resistance to the air flow. That is,
Since the airflow flowing from the inlet opening 11 hits the valve stem and hardly collides with this rectangular wall surface 31, the rectangular wall surface 31 does not act as a resistance to the airflow.
This is because if the width of 31 is made wider, the resistance increases.
On the contrary, if the rectangular wall surface 31 is formed to have a narrower wall surface, the strength performance in this portion becomes insufficient.

Therefore, according to this embodiment, as shown in FIG. 3, the air flowing from the inlet opening 13 into the intake port and flowing along the arrow D directly flows into the cylinder 22 or the combustion chamber from the central outlet opening 13. Also, the air that flows in from the inlet opening 11 and flows along the arrows C and E passes through the outlet openings 12 and 14 on both sides and flows into the combustion chamber with almost no collision with the walls 18 and 19. Thus, the air flow along the arrows C and E is not disturbed by the walls 18 and 19, and as a result, the resistance that the air flow receives is greatly reduced, and the intake efficiency is improved.

[Effect of device]

As described above, according to the present invention, the intake air is not subjected to a large resistance by the wall near the outlet opening,
A sufficient amount of air flows into the combustion chamber through each outlet opening,
Sufficient intake efficiency can be obtained, so that the engine output can be improved.

[Brief description of drawings]

FIG. 1 (A) is a perspective view showing the inside of an intake port according to an embodiment of the present invention, FIG. 1 (B) is a perspective view showing the inside of a conventional intake port, and FIG. 2 is an embodiment of the present invention. FIG. 3 is a cross-sectional view showing a cylinder head to which the example is applied, and FIG. 3 is a plan view schematically showing the shape of the intake port. 10 ... intake port, 11 ... inlet opening, 12,13,14 ... outlet opening, 15,16,17 ... stem guide, 18,19 ... wall, 22 ... cylinder, 31 ... rectangular wall.

Front Page Continuation (72) Inventor Go Yamamura, Toyota City, Toyota City, Aichi Prefecture, Toyota Toyota Motor Co., Ltd. (72) Inventor, Hidefumi Hashizume, Toyota City, Toyota City, Aichi Prefecture, Toyota Motor Co., Ltd.

Claims (1)

[Scope of utility model registration request] 1. A cylinder is provided with three intake valves, and each intake port has three outlet openings and one inlet opening opened and closed by each intake valve, and the intake port inner wall has In an intake port structure of an internal combustion engine in which a stem guide that supports the valve stem of the intake valve projects, an inner wall portion that is substantially upright in the vicinity of the three outlet openings of the intake port has a peripheral portion of a central outlet opening. A first portion in contact with a rear surface of a corresponding valve stem of the intake valve when viewed from the inlet opening;
An intake port structure for an internal combustion engine, wherein the intake port structure is formed so as to have a second portion that reaches a peripheral portion of another outlet opening from both sides of the portion.