JPH0475365B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a multi-valve engine for use in motorcycles, etc., which has three intake valves and two exhaust valves in the same cylinder.

Conventionally, this type of engine has a combustion chamber b in a cylinder head a, as shown in FIGS. 1 and 2, for example.
Two intake valves c and two exhaust valves d are arranged on one side and the other side surrounding the center of the combustion chamber, and one intake valve c is placed at the center of the combustion chamber b.
It is known that a total of three intake valves C are provided in order to improve the output, but in this type, the intake valve C is provided in the center position, so the placement position of the spark plug e is lateral to the center position. In order to obtain uniform combustion, it is necessary to install a pair of spark plugs e on both sides of the center position in the lateral direction, which is cumbersome.In addition, to avoid interference with the spark plug e, the camshaft f is placed between the spark plugs e. This is disadvantageous because it has to be configured in a so-called DOHC type in which a pair of valves are installed horizontally on both sides of the arrangement part, and furthermore, in this one, the axes of the intake valves c and the exhaust valves d are parallel to each other. Because each valve is arranged, the difference in level between the end faces of each valve perpendicular to the axis facing into the combustion chamber b creates unevenness on the upper wall surface of the combustion chamber b, which tends to cause uneven combustion, resulting in poor combustion performance. accompanied by.

An object of the present invention is to provide a multi-valve engine that eliminates such disadvantages.
In a multi-valve engine that has three intake valves and two exhaust valves in the same cylinder, the cylinder head is surrounded by the center of a circular combustion chamber in plan view, with these intake valves on one side and the exhaust valves on the other side. The valves are arranged radially so that the axis of each valve intersects the axis of the cylinder, and the cylinder head is placed between the two exhaust valves, and the spark plug is placed in an inclined position so that its tip faces the center of the combustion chamber. At the same time, a common camshaft is horizontally installed at an intermediate position between the intake valve arranging part and the exhaust valve arranging part of the cylinder head, and a camshaft is installed at both ends of the exhaust valve arranging part and the intake valve arranging part. The two intake valves provided on the side are interlocked with the camshaft via each rocker arm and each sub-rocker arm, and the intake valve provided in the middle of the intake valve arrangement section is connected to the camshaft in parallel with a plane perpendicular to the camshaft. , and the intake valve is interlocked with the camshaft via a rocker arm.

Next, the present invention will be explained with reference to the illustrated embodiments.

With reference to FIGS. 3 and 4, 1 is a cylinder;
2 indicates a cylinder head, and the cylinder head 2
The center of the combustion chamber 3 is surrounded by three intake valves 4 on one side and two exhaust valves 5 on the other side.
The exhaust valves 5, 5 are arranged radially so as to intersect with the axis of the cylinder head 2, and further located between the two exhaust valves 5, 5 on the side of the cylinder head 2 where the exhaust valves 5, 5 are arranged, so that the tip thereof is located in the combustion chamber. The spark plug 6 was inserted in an inclined position so as to face the center of the spark plug 3.

According to this, the upper wall surface of the combustion chamber 3 can be formed into a smooth concave spherical surface with no unevenness and whose center of curvature is the intersection of the axes of the valves 4 and 5 and the axis of the cylinder 1. And the cylinder head 2
A space in which no spark plug 6 is present is formed between one side on which the intake valve 4 is disposed and the other side on which the exhaust valve 5 is disposed, and a common camshaft 7 is placed horizontally in this space. The so-called SOHC which drives the respective valves 4 and 5 by the camshaft 7
It becomes possible to configure it into a type.

In addition, in the case of an engine having a sub-combustion chamber, 3
One of the valve ports of the intake valves 4 is used as an opening of the auxiliary combustion chamber to the main combustion chamber.

The interlocking mechanism between the camshaft 7 and each of the valves 4 and 5 includes an intake rocker arm shaft 9 that pivotally supports three rocker arms 8 on the camshaft 7 in parallel therewith, and two rocker arms 8'. A rocker arm shaft 9' for the exhaust that is pivotally supported is arranged in parallel, and the valves 4 and 5 are linked to the camshaft 7 via the rocker arms 8 and 8'. Valve 4, 4,
The axis of the middle intake valve 4 among the intake valves 4 is located on a plane perpendicular to the camshaft 7, that is, the plane perpendicular to the rocker arm shaft 9 parallel to the camshaft 7, and the axis of each intake valve 4 on both sides of the Since the axis of the exhaust valve 5 does not coincide with the plane perpendicular to the rocker arm shafts 9, 9', these valves 4, 5 swing in the axial direction of the rocker arms 8, 8' and further of the valves 4, 5. It is configured to be driven via each moving sub-rocker arm 10, 10'.

As described above, according to the present invention, three intake valves are arranged radially around the center of the combustion chamber on one side and two exhaust valves on the other side, and the two exhaust valves are arranged radially. The ignition plug is installed at an angle so that its tip faces the center of the combustion chamber.The upper wall surface of the combustion chamber is formed into a concave spherical surface with few irregularities to improve combustion performance, and it is possible to improve combustion performance. The camshaft can be placed in the middle position between the placement part and the exhaust valve placement part without causing any interference with the spark plug, and one common camshaft is used.
A SOHC type multi-valve engine can be obtained, which is advantageous in making the engine smaller and lighter. Furthermore, since the two exhaust valves and the two intake valves on both end sides are driven via the rocker arm and subrocker arm, respectively, even if these intake and exhaust valves are arranged on a plane diagonally intersecting the camshaft. , each valve can be driven such that no lateral force is applied;
The intermediate intake valve, which is sandwiched between two intake valves and cannot secure space for the sub-rotsuka arm, is arranged parallel to the plane perpendicular to the camshaft, so that even if the intake valve is directly driven by the roka arm, the lateral force will be reduced. In this way, an engine as compact as possible is obtained in which five radially arranged valves can be driven by a single camshaft.

[Brief explanation of the drawing]

Figure 1 is a plan view of a conventional multi-valve engine.
2 is a cross-sectional side view thereof, FIG. 3 is a plan view of a cylinder head portion of an example of the engine of the present invention, and FIG. 4 is a cross-sectional side view taken along the line -- in FIG. 1...Cylinder, 2...Cylinder head, 3...
...Combustion chamber, 4...Intake valve, 5...Exhaust valve, 6...Spark plug, 7...Camshaft.

Claims (1)

[Claims] 1 In a multi-valve engine equipped with three intake valves and two exhaust valves in the same cylinder, the cylinder head is surrounded by the center of a circular combustion chamber in plan view, with these intake valves on one side and these on the other side. Exhaust valves are arranged radially so that the axis of each valve intersects the axis of the cylinder, and a spark plug is placed between the two exhaust valves on the cylinder head so that its tip faces the center of the combustion chamber. The camshaft is inserted in an inclined position, and a common camshaft is installed horizontally at an intermediate position between the intake valve arrangement part and the exhaust valve arrangement part of the cylinder head, The two intake valves provided at both ends of the camshaft are interlocked with each other via each rocker arm and each sub-rocker arm, and the intake valve provided in the middle of the intake valve arrangement portion is connected to the surface orthogonal to the camshaft. A multi-valve engine characterized in that the intake valve is arranged parallel to the camshaft and is interlocked with the camshaft via a rocker arm.