JPH07667Y2 - Intake structure of internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to an intake structure for an internal combustion engine of an automobile, etc.
The present invention relates to an intake structure having a branched intake port.

(Prior Art) Recently, internal combustion engines such as automobiles are required to be miniaturized in addition to performance improvements such as high output, low fuel consumption, and low exhaust. Attempts to realize these issues from various directions. Has been.

An example of such a conventional intake structure for an internal combustion engine is described in Japanese Patent Application Laid-Open No. 59-15613.
Shown as shown.

In the figure, reference numeral 1 is a cylinder head, and an intake port 4 that guides an air-fuel mixture from a carburetor not shown in the cylinder head 1 to a combustion chamber 3 via an intake manifold 2.
Further, an exhaust port 5 that guides exhaust gas from the combustion chamber 3 is provided. At least the intake port 4 is the cylinder head 1
Air inlet opening on the side wall (wall on the left side of the drawing) of the
4a and two air outlets 4b opening in the combustion chamber 3 of the engine,
4c (these outlets are arranged in the front and back direction of the drawing, and one outlet is hidden behind the other two outlets and is not visible) has a two-branch shape. Valve guides 8 and 9 that support an intake valve 6 and an exhaust valve 7 are disposed above the combustion chamber 3, and the intake valve 6 is driven by a swing arm 11 that is driven by a cam 10. The swing arm 11 is swingably supported by an end pivot 12 provided outside the cylinder head 1 with respect to the valve guide 8 and directly above the intake port 4. The end pivot 12 is for adjusting the clearance between the contact portions of the swing arm 11 and the intake valve 6 without adjustment. For example, a screw type or hydraulic type (so-called lash adjuster; HLA) is used.

Although not shown, the intake valve 6 and the exhaust valve 7 have a four-valve structure in which two valves are provided for each combustion chamber 3, and two intake valves 6 and two exhaust valves 7 are provided for each intake valve 6.
A system intake port 4 is provided.

(Problems to be Solved by the Invention) However, in such a conventional intake structure for an internal combustion engine, since the intake port 4 is located directly below the end pivot 12, for example, in order to improve intake efficiency. When the intake port 4 is designed to have a small bend, in the extreme case, the base of the end pivot 12 (indicated by reference numeral a for convenience) projects into the intake port 4 and rather deteriorates the intake efficiency. was there.

(Purpose of the Invention) Therefore, the present invention optimizes the positional relationship between the intake port and the end pivot and the shape of the intake port.
The purpose is to avoid interference with the end pivot, reduce bending of the intake port, and sufficiently improve intake efficiency.

(Issues for solving the problems) The intake structure of the internal combustion engine according to the present invention is designed to achieve the above object.
A bifurcated intake port that connects between one air inlet opening on the side wall of the cylinder head and two air outlets opening on the combustion chamber of the engine, and opens and closes each of the two air outlets. An intake structure for an internal combustion engine, comprising: two intake valves; two swing arms that drive each of the two intake valves; and two end pivots that support the fulcrum-side ends of the two swing arms. A center line of the intake port is passed between the two end pivots, and a branch wall of the intake port is located between the combustion chamber and the end pivot and close to the two end pivots. It is provided with a configuration to allow it.

(Operation) In the present invention, since the center line of the intake port is not located directly below the end pivot, for example, even if the bend of the intake port is reduced, the projection of the end pivot into the port is avoided and the required intake efficiency is obtained. Improvement is planned. Furthermore, since the branch wall of the intake port is close to the two end pivots (in other words, far from the combustion chamber), the branch angle of the intake port is small, and the bending of the intake port in the horizontal plane is also small, so the intake efficiency is improved. Is further enhanced.

(Example) Hereinafter, the present invention will be described with reference to the drawings.

1 and 2 are views showing an embodiment of an intake structure for an internal combustion engine according to the present invention.

First, the structure will be described, but the members having the same structures as those of the conventional example shown in FIG.

FIG. 1 is a sectional view showing the structure of the main part thereof, and the exhaust side is not shown for convenience of explanation.

In the figure, 21 is a cylinder head, and an intake manifold 22 is connected to the cylinder head 21. The intake manifold 22 is provided with an injector 23, and the injector 23 atomizes the fuel into a conical shape and injects the fuel, as indicated by A in the figure. The intake port 25 is connected to the intake passage 24 of the intake manifold 22, and the intake port 25 is one system near the end pivot 12, but after passing near the end pivot 12, it is branched into two systems. The air-fuel mixture is introduced into the combustion chamber 3 via different lines. FIG. 2 is a diagram showing the positional relationship between the intake port 25 and the two end pivots 12a and 12b and the shape of the intake port 25. As can be understood from this figure, the point of this embodiment is 2 The center line La of the intake port 25 is passed between the two end pivots 12a and 12b, and the branch wall 25c between the two branch side intake ports 25a and 25b of the intake port 25 is connected to the combustion chamber 3 and two. End pivot 12a, 12b
12 end pivots between and as much as possible
It is located close to a and 12b. In this figure, 25d is one air inlet opening on the side wall of the cylinder head (see reference numeral 21 in FIG. 1), 25e and 25f are two air outlets opening on the combustion chamber 3 of the engine, respectively.
Reference numerals a and 6b are two intake valves similar to the conventional example that open and close each of the two air outlets 25e and 25f. Returning to FIG. 1, the cylinder head 21 and the intake manifold 22 are formed with an introduction path 26 for guiding fuel to the intake port 25 along the spray direction of the injector 23, and the axis line of the injector 23 is almost combusted. The intake ports 25a and 25b of the two systems opening to the chamber 3 are provided so as to coincide with the center of the opening.

A plug tube 27 is opened in the combustion chamber 3, and a spark plug (not shown) is housed in the plug tube 27.
Reference numeral 28 is a cam journal that supports a cam shaft (not shown), and the valve stem 30 supported by the valve guide 29 reciprocates following the cam of the cam shaft. A valve spring retainer 31 is provided on the valve stem 30, and the valve spring retainer 31 transmits the biasing force of the valve spring 32 to the valve stem 30 to close a valve (not shown) provided at the tip of the valve stem 30. To

According to the above configuration, as can be easily understood from FIG. 2, since the center line La of the intake port 25 is not located directly below each of the two end pivots 12a and 12b, for example,
Even if the bend of the intake port 25 is reduced to make it a high port, the intake ports of the end pivots 12a and 12b
Since the protrusion into 25 can be avoided, the required intake efficiency can be improved. Furthermore, the branch wall 25c of the intake port 25
Is close to the two end pivots 12a and 12b (in other words, far from the combustion chamber 3), the branch angle of the intake port 25 (see reference numeral α in FIG. 2) is small, and the bending of the intake port 25 in the horizontal plane is small. Therefore, the effect of improving the intake efficiency can be further enhanced. Therefore, the engine output can be improved. Further, by increasing the number of high ports, most of the fuel injected from the injector 23 is directly supplied to the combustion chamber 3, so that the amount of fuel adhering to the wall surface of the intake port 25 can be reduced and the mixture gas It is possible to prevent leaning and obtain a good air-fuel ratio.

(Effect) According to the present invention, since the center line of the intake port is not located directly below the end pivot, for example, even if the bending of the intake port is reduced, the protrusion of the end pivot into the port can be avoided, and the required It is possible to improve intake efficiency.
Further, since the branch wall of the intake port is close to the two end pivots (in other words, far from the combustion chamber), the branch angle of the intake port is small, and the bending of the intake port in the horizontal plane can be reduced, thereby improving the intake efficiency. The improvement effect can be further enhanced.

[Brief description of drawings]

FIGS. 1 and 2 are views showing an embodiment of an intake structure for internal combustion according to the present invention. FIG. 1 is a sectional view showing a main part thereof, and FIG. 2 is a perspective view showing an intake system passage thereof. FIG. 3 is a sectional view of an essential part showing a conventional intake structure for an internal combustion engine. La …… center line, 3 …… combustion chamber, 6a, 6b …… intake valve,
11 …… Swing arm, 12a, 12b …… End pivot, 21 …… Cylinder head, 25 …… Intake port, 25c…
… Branching wall, 25d …… Air inlet, 25e, 25f …… Air outlet.

Claims (1)

[Scope of utility model registration request] 1. A two-branch-shaped intake port connecting between one air inlet opening in a side wall of a cylinder head and two air outlets opening in a combustion chamber of an engine, and the two air outlets. Two intake valves that open and close each of the
An intake structure for an internal combustion engine, comprising: two swing arms that drive each of the two intake valves; and two end pivots that support fulcrum-side ends of the two swing arms. While passing the center line of the intake port between
An intake structure for an internal combustion engine, characterized in that a branch wall of the intake port is arranged between the combustion chamber and the end pivot and close to the two end pivots.