JP3109266B2 - Oil injection structure of oil-cooled engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oil injection structure of an oil-cooled engine, and more particularly to an oil-cooled structure of an engine cylinder head of an engine equipped with a SOHC (single overhead camshaft) valve train for a motorcycle. The present invention relates to an oil injection structure of an oil-cooled engine suitable for use.

[0002]

2. Description of the Related Art Some engines for motorcycles and the like inject cooling oil in the cylinder head to the rear side of the combustion chamber of the cylinder head in order to enhance the cooling efficiency of the engine. Conventionally, this type of engine has a configuration as shown in FIG. 4 (with a cylinder head cover member removed). An oil cooling pipe 10 is inserted from the spark plug (not shown) side of the cylinder head, and cooling oil is injected from the oil cooling pipe 10 to the back side of the cylinder head combustion chamber to cool the cylinder head. FIG. 4 shows a state in which the upper structure of the cylinder head is removed, as viewed from above. 12 is a hole for a spark plug, 14 is a cam sprocket, 16 is a camshaft, 18 is an intake / exhaust valve, 20 is a gasket surface, and 22 is a mounting bolt hole.

[0003]

However, in the oil injection structure of the conventional oil-cooled engine, a space for an oil-cooling pipe is required in addition to a space for a sparging plug in a cylinder head, and this space is secured. Therefore, the included angle of the valve becomes large. Therefore, there is a problem that the engine of the cylinder head having a small valve included angle cannot be oil-cooled. In addition, in an engine having a large valve included angle, the combustion chamber volume is naturally large, so that there is a problem in that the cooling loss increases and the thermal efficiency decreases. In addition, since the rocker arm is large and heavy, and the equivalent inertial weight is large, there is a problem that the engine does not rotate at a high speed. Further, there is a problem that the engine becomes large and heavy because the cylinder head becomes large.

The present invention has been made in order to solve the above-mentioned conventional problems, and provides an oil injection structure of an oil-cooled engine in which a cylinder head having a small included angle of a valve can be oil-cooled. The task is to

[0005]

SUMMARY OF THE INVENTION The present invention relates to an oil-cooled engine for cooling an engine having an overhead cam by injecting oil from an oil-cooling pipe behind a combustion chamber of the cylinder head to cool the cylinder head. In the injection structure, the problem is solved by providing the oil cooling pipe so as to avoid the cam chain and the cam sprocket from the cam chain and the cam sprocket side and to face the back side of the combustion chamber of the cylinder head. .

[0006]

In the present invention, the oil cooling pipe is provided so as to avoid the cam chain and the cam sprocket from the cam chain and the cam sprocket side and to face the back side of the combustion chamber of the cylinder head. There is no need to avoid the spark plug and provide it on the cylinder head. Therefore, the oil cooling pipe can be provided without disturbing the spark plug even in the cylinder head having a small valve included angle, and thus even an engine having such a small valve included angle can be cooled.

[0007]

Embodiments of the present invention will be described below in detail with reference to the drawings. In the present embodiment, as shown in FIGS.
An engine (single-cylinder engine) provided with a SOHC type valve train, which is configured to reduce the angle between the valve intake / exhaust 18 of the cylinder head 24 and to make the entire head 24 compact and oil-cooled. 3) is an oil injection structure of an oil-cooled engine provided in the cylinder head 24. The same parts as those in the conventional oil injection structure shown in FIG. 4 are denoted by the same reference numerals.

FIG. 1 shows a cylinder head 2 of the engine.
FIG. 4 is a cross-sectional view of a main part, specifically showing a periphery of the device. In FIG. 1, the structure of the lower portion of the cylinder 35a of the engine is well-known, so that its configuration is not shown. FIG. 2 shows the cylinder head 2
4 is a top view of the cylinder head 24 when the upper structure is removed, FIG. 3B is a side view of the cylinder head 24, FIG.
4 shows a detailed structure of the cylinder head 24 around the oil cooling pipe 30.

In the engine of the embodiment, the valve 18
Is smaller, there is no space for the oil cooling pipe 30 to pass through on the spark plug side (the side with the spark plug hole 12). Therefore, as shown in FIGS. 1 and 2, the oil cooling pipe 30 is passed through the cylinder head 24 from the cam chain 32 and the cam sprocket 14 side so as to avoid the cam chain 32 (shown by a broken line) and the cam sprocket 14. The oil injection holes 30a, 30b are provided so that the front and side oil injection holes 30a, 30b of the oil cooling pipe 30 face the rear side 34 of the combustion chamber.
In this case, oil is injected into the combustion chamber rear side 34 for cooling. The oil cooling pipe 30 is provided with an oil injection hole 3 for supplying oil for cam journal lubrication.
0c is formed. 36 is a combustion chamber formed by the inner surface of the engine cylinder 35a and the upper surface of the piston 35b, 37a is the engine cylinder, and 37b is the cylinder 3
7a is an air cooling fin, 37c is a connecting rod, 38 is a cam chain chamber, 40a is a rocker arm, and 40b is a rocker shaft.

As shown in detail in FIG. 3, the oil cooling pipe 30 passes through the hole 24a formed in the outer wall of the cam chain chamber 38 of the cylinder head 24, and further passes through the cam chain chamber 3.
8 through a hole 38a formed in the inner wall of the combustion chamber rear side 34.
It is arranged to face. Also, the oil cooling pipe 30
Has flanges 42a and 42b extending in a direction perpendicular to the axis, and one of the flanges 42a is
Are provided in the direction of entry into the back side 34 of the combustion chamber, and are sealed by an O-ring 44a. The other flange 42b is sealed by an O-ring 44b provided outside the cylinder head 24.

The diameter d of the flange 42a is smaller than the diameter D of the hole 24b formed in the cylinder head 24, so that the oil cooling pipe 30 can be mounted from outside the engine. Also, the oil cooling pipe 30
An oil injection hole 30a capable of jet injection is provided at an axial end portion of the nozzle, so that injection can be performed in the axial forward direction. The amount of oil injected from the oil cooling pipe 30 and the amount of oil fed to the cam journal can be adjusted by the diameters of the holes 30a, 30b, and 30c formed in the oil cooling pipe 30 and the jet at the tip. The oil cooling pipe 30 is attached after the cam is attached.

In the present embodiment, since the configuration is as described above, the angle between the valve intake and exhaust 18 of the cylinder head 24 can be reduced to make the entire head 24 compact and oil-cooled. At the same time, the cam journal can be appropriately lubricated.

In the above-described embodiment, the present invention is applied to an SOHC type engine. However, the present invention can be applied to other types of engines such as a DOHC type engine.

[0014]

As described above, according to the present invention, it is possible to oil-cool a cylinder head engine in which the included angle of the valve is reduced. Therefore, since the angle between the valves of the engine can be reduced, the volume of the combustion chamber is naturally reduced, so that the cooling loss is reduced and the thermal efficiency is improved. Further, since the rocker arm is small and light, the equivalent inertial weight is reduced, and the engine rotates to a high speed. Also,
Since the cylinder head is small, excellent effects such as a small and light engine can be obtained.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a main part of an engine provided with an oil cooling pipe according to an embodiment of the present invention.

FIG. 2A is a top view of the engine provided with the oil cooling pipe, and FIG. 2B is a side view of the engine.

FIG. 3 is a sectional view of a main part showing a detailed attachment configuration of an oil cooling pipe of the engine.

FIG. 4 is a detailed top view of an engine cylinder head to which a conventional oil cooling pipe is attached.

[Explanation of symbols]

 Reference Signs List 12 spark plug mounting hole 14 cam sprocket 16 cam shaft 18 intake / exhaust valve 24 cylinder head 24 24a oil cooling pipe 30 mounting hole 30 oil cooling pipe 30 30a, 30b, 30c oil injection hole 32 cam chain 32 34 back side of combustion chamber 34 36 Combustion chamber 36 38 Cam chain chamber 38 38a Oil cooling pipe 30 mounting hole 40a, 40b Rocker arm, rocker shaft 42a, 42b Flange

Claims (1)

(57) [Claims] In an oil injection structure of an oil-cooled engine for injecting oil from an oil-cooling pipe to a back side of a combustion chamber of a cylinder head of an engine having an overhead cam to cool the cylinder head, an oil-cooling pipe is provided. The oil injection structure of an oil-cooled engine, wherein the oil injection structure is provided so as to avoid the cam chain and the cam sprocket from the cam chain and the cam sprocket side and to face the back side of the combustion chamber of the cylinder head.