JPS648169B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an internal combustion engine with a large specific output, particularly a multi-valve internal combustion engine having at least two intake valves and an exhaust valve and suitable for use in motorcycles. The objective is to effectively cool the cylinder head and to reduce the size and weight of the cooling means as much as possible.

In general, multi-valve internal combustion engines are often used in motorcycles and sports cars because they have less ventilation resistance for intake and exhaust and can easily produce high output. However, the structure of the cylinder head is complicated, and the areas around the exhaust valve and spark plug are likely to overheat. Therefore, it is conceivable to cool the cylinder head using lubricating oil, but a structure in which lubricating oil simply flows may not necessarily effectively cool the area around the plurality of exhaust valves.

In this invention, a jacket is formed around an intake and exhaust valve, a guide wall is provided inside the jacket to define an intake port side and an exhaust port side, and by opening one end of this guide wall, the exhaust gas is It is characterized in that a flow path is formed from the port side to the intake port side, an inlet is provided at one end of the flow path on the exhaust port side, and an outlet is provided at the other end. The present invention will be explained with reference to illustrated embodiments. In the figure, 1 is the main body of the engine;
It consists of a crank chamber 2, a cylinder 3 and a cylinder head 4. 5 indicates an intake pipe, and 6 indicates an exhaust pipe. Reference numeral 7 denotes a trochoid type cooling pump that is attached to the side of the cylinder head 4 and pivoted by a camshaft, which will be described later.It is provided in the oil supply passage S, and its suction passage 7a is a lubrication pump formed at the bottom of the crank chamber 2. The discharge passage 7 opens at the bottom of the oil tank 8.
b communicates with an inlet of a jacket 9, which will be described later, formed within the cylinder head 4. Reference numeral 10 denotes a radiator installed in front of the vehicle body frame (not shown), which is installed in the oil return path R, and which connects the return oil to the jacket 9 via the high temperature passage 10a and to the oil tank 8 via the low temperature passage 10b. They each lead to Route 11. 12 is a lubricating oil pump provided in the crank chamber 2, 13 is its suction passage, and 14 is a discharge passage leading to each sliding portion. Cylinder head 4 is the third
As shown in the figure, a combustion chamber 15 is formed on the lower surface, and an intake port 16 and an exhaust port 17 are connected via an intake valve 18 and an exhaust valve 19, respectively. The intake valve 18 and the exhaust valve 19 are arranged so as to face each other, each of which operates simultaneously, and are opened and closed by an intake camshaft 21 and an exhaust camshaft 22 via a tappet 20. 23 is a valve spring. A jacket 9 is formed on the upper surface of the wall member 24 forming the combustion chamber 15 by an upper wall 25 and a peripheral wall 26 around the intake valve 18 and the exhaust valve 19. As shown in FIG. 2, the jacket 9 has an inlet 9a communicating with the discharge passage 7b of the cooling pump and an outlet 9b communicating with the high temperature passage 10a.
A series of flow paths are created by partitioning the area between the exhaust valve 19 and the exhaust valve 19, and the refrigerant first cools the area around the exhaust valve 19, and then flows to the opposite side of the guide wall 27 to the intake valve 1
It is designed to cool the area around 8. 28 is a spark plug, and 29 is a cylindrical wall surrounding the outer periphery thereof. The guide wall 27 extends from the cylindrical wall 29 so as to define the interior of the jacket into an exhaust port 17 side and an intake port 16 side.By opening one end of the guide wall 27, the exhaust port The flow path is formed from the 17 side to the intake port 16 side. The inlet 9a is the exhaust port 17 of the flow path.
The outlet 9b is provided at the other end of the flow path on the intake port 16 side.

The cooling device configured as described above operates as follows when the engine is operated.

That is, the cooling pump 7 is driven by the exhaust camshaft 22 and sucks the lubricating oil in the oil tank 8 and pumps it into the jacket 9. The lubricating oil flows into the jacket 9 from the inlet 9a and flows upward while cooling the right side of the guide wall 27, that is, the periphery of the exhaust port 17 and the outer surface of the cylindrical wall 29. The air then passes around the upper end of the guide wall to cool the left side, that is, around the intake port 16, and flows out from the outlet 9b. Therefore, the wall member 24 is cooled uniformly over its entire surface.
The lubricating oil heated in the cylinder head 4 reaches the radiator 10 via the hot passage 10a, is cooled, passes through the cold passage 10b, and returns to the oil tank 8 from the return oil passage 11.
Reflux into the inside. On the other hand, the lubricating oil is sent by the pump 12 to the bearings and gears in the crank chamber 2 and into the sliding parts in the cylinder head 4, and is returned to the oil tank 8 by gravity.

As described above, this invention circulates the lubricating oil in the lubricating oil tank to the jacket formed near the intake and exhaust valves of a multi-valve internal combustion engine via a cooling pump and a radiator, and the lubricating oil is circulated through a plurality of exhaust valves. The exhaust valves can be cooled one by one in series. Therefore, since the amount of lubricating oil flowing around each exhaust valve per unit time can be increased as much as possible, the area around the exhaust valve, which has the largest heat load in a multi-valve internal combustion engine, can be effectively cooled. Furthermore, since the lubricating oil is used as the refrigerant, there is no need to provide an oil tank for storing the lubricating oil as the refrigerant, and the structure of the vehicle body can be prevented from becoming complicated. Furthermore, the lubricating oil used as a refrigerant is cooled to a predetermined low temperature by the radiator and then returned to the oil tank, which prevents the lubricating oil temperature from rising excessively and reduces the tendency for the lubricating function to deteriorate during high-output operation. Deterred.

As in this example, if only the wall surface of the combustion chamber of the cylinder head is liquid-cooled and the rest is air-cooled, the radiator can be kept small. The cooling capacity of the engine is increased without making any major changes to the engine's configuration, and further improvements in output can be expected.

[Brief explanation of drawings]

The drawings show an example of the implementation of the present invention, and FIG. 1 is an overall view schematically showing a cooling device, FIG. 2 is an enlarged view of the main part of FIG. 1 showing a cross section, and FIG. FIG. 3 is an enlarged view of main parts showing a cross section. 7... Cooling pump, 8... Lubricating oil tank, 9... Jacket, 10... Radiator, 12... Lubricating oil pump.

Claims (1)

[Claims] 1. In a multi-valve internal combustion engine that has a lubricating oil tank 8 and is provided with at least two intake valves 18, 18 and exhaust valves 19, 19 per cylinder, a cooling pump 7 is installed around the intake and exhaust valves 18, 19. A jacket 9 is formed which is connected to the lubricating oil tank 8 via the radiator 10, and inside this jacket 9 there are connected an intake port 16 side and an exhaust port 17.
A guide wall 27 is provided that defines the sides, and this guide wall 2
Exhaust port 17 by opening one end of 7.
A cooling device for a multi-valve internal combustion engine, in which a series of flow channels are formed from the side to the intake port 16 side, an inlet 9a is provided at one end of the flow channel on the exhaust port 17 side, and an outlet 9b is provided at the other end. .