JPS6318102A - Sohc type multicylinder internal combustion engine - Google Patents

Abstract

PURPOSE:To control the occurrence of knocking and shorten the length of a cylinder head by forming a cylindrical part having an ignition plug inserting hole extending obliquely toward the center of the ceiling of a combustion chamber in a body with a cam holder. CONSTITUTION:A cam holder 31 is composed of a lower holder 27 provided in a body with a cylinder head 2 on its upper part and an upper holder 28 bolted on the upper part of said holder 27, and supports a cam shaft 14 and rocker arm shafts 15, 16 each located on an intake and an exhaust side. In the above constitution, said cam holder 31 is provided in a body with a cylindrical part 37 having an inserting hole 36 extending obliquely toward the center of the ceiling of a combustion chamber 6. An ignition plug P is inserted in said inserting hole 36, and thread-mounted in a tapped hole 38 with its top facing to said center of the ceiling of the combustion chamber 6. In a cylinder at outside end, rocker arms 17, 18 on an intake or an exhaust side on the side on which the cylindrical part 37 is located are arranged on the inner side of said part 37 against the axis of the cam shaft 14.

Description

Detailed Description of the Invention A1 Object of the Invention (11 Industrial Application Fields) The present invention is directed to a single spark plug, in which a spark plug is arranged facing the ceiling of a combustion chamber and is rotatably arranged above the combustion chamber. On both sides of the camshaft, the intake side and exhaust side rocker arm shafts are supported by holder members, and the intake side rocker arm shaft has one
An intake side rocker arm that interlocks and connects one intake valve and camshaft per cylinder is swingably supported, and an exhaust side rocker arm that interlocks and connects the exhaust valve and camshaft is supported on the exhaust side rocker arm shaft. This invention relates to an SOHC multi-cylinder internal combustion engine.

t2) Prior Art Conventionally, in SOHC multi-cylinder internal combustion engines, the spark plug has generally been placed at a position offset from the center of the ceiling surface of the combustion chamber.

(3) Problems to be Solved by the Invention However, the above-mentioned conventional device tends to cause non-king. Furthermore, in order to insert the spark plug from the side of the cylinder head, it is necessary to build up the area around the spark plug on the ceiling surface of the combustion chamber, resulting in an undesirable shape of the combustion chamber.

The present invention was made in view of the above circumstances, and it solves the above problems by arranging the spark plug in the center of the combustion chamber, and also makes it possible to shorten the length of the engine body along the axial direction of the camshaft. The purpose of the present invention is to provide an SOHC type multi-cylinder internal combustion engine.

B0 Structure of the Invention (Means for Solving 11 Problems) According to the present invention, in order to insert the ignition plug into the center of the ceiling surface of the combustion chamber, the intake valve and the exhaust valve are connected to the center of the ceiling surface and extend upward toward the ceiling surface of the combustion chamber. A cylindrical part that forms an insertion hole that is inclined to one side is integrally provided in the holder member, and in the outermost cylinder along the axial direction of the camshaft, the cylinder part is installed on the intake side or the side where the cylindrical part is arranged. An exhaust side rocker arm is arranged inward of the cylindrical portion along the axial direction of the camshaft.

(2) Function The ignition plug is placed facing the center of the ceiling surface of the combustion chamber through the insertion hole, and the occurrence of non-king can be prevented. Moreover, by locating the rocker arm on the side where the cylindrical part is arranged on the inner side of the cylindrical part in the outermost cylinder along the axial direction of the camshaft, the distance of the cylinder head along the axial direction of the camshaft can be reduced. This can contribute to reducing the size of the cylinder head.

(3) Embodiment Hereinafter, an embodiment in which the present invention is applied to an SOHC type four-cylinder internal combustion engine will be explained with reference to the drawings. First, in FIGS. The main body E includes a cylinder block 1 and a cylinder head 2 which is superimposed and connected to the upper part of the cylinder block 1 via a gasket 3, and four cylinders 4 bored in the cylinder block 1 have pistons 5. are rubbed together. A combustion chamber 6 is defined by the cylinder block 1, cylinder head 2, and piston 5.
The ceiling surface of the building is formed in the shape of a roof that slopes toward each other.

One intake valve lower is opened in one example of the ceiling surface of each combustion chamber 6, and an intake boat 9 communicating with the intake valve lower is bored in the cylinder head 2. Furthermore, the intake port 9 is connected to a fuel supply device, such as a carburetor, via an intake manifold (not shown).

In addition, one exhaust valve port 8 is opened on the other side of the ceiling surface of the combustion chamber 6, and this exhaust valve port 8 is connected to the exhaust manifold ( (not shown).

The cylinder head 2 has an intake valve 1 that opens and closes the intake valve lower.
1 and an exhaust valve 12 that opens and closes the exhaust valve port 8 are supported so as to be vertically slidable. Furthermore, the intake valve 11 and the exhaust valve 12 are arranged on both sides of the central axis 13 of the cylinder 4 so that their upper ends are inclined away from each other.

A single camshaft 14 common to each cylinder is rotatably disposed above the combustion chamber 6 and near the central axis 13 between the intake valve 11 and the exhaust valve 12. This camshaft 14
A total of three intake-side rocker arm shafts 15 for all cylinders are fixedly arranged parallel to the camshaft 14 at a position above the camshaft 14 between the camshaft 14 and the exhaust valve 12. An exhaust-side rocker arm shaft 16 common to all cylinders is fixedly disposed in parallel with the camshaft 14 at a position above the camshaft 14 between the two.

One intake rocker arm 17 per cylinder is swingably supported on each intake rocker arm shaft 15, and the outer end of each rocker arm 17 is connected to the upper end of each intake valve 11 via an adjuster 19. The slipper surfaces 20 provided at each inner end are in sliding contact with the intake side valve operating cam 21 of the camshaft 14 .

Further, one exhaust side rocker arm 18 per cylinder is pivotally supported on the exhaust side rocker arm shaft 16, and the outer end of each rocker arm 18 is connected to the upper end ratio of the exhaust valve 12 via an adjuster 22. A slipper surface 23 provided at each inner end is in sliding contact with an exhaust side valve operating cam 24 of the camshaft 14. Therefore, as the camshaft 14 rotates, the intake side and exhaust side rocker arms 1
7゜18 is the intake side and exhaust side rocker arm shaft 15゜1
6, respectively, and can open and close the intake and exhaust valves 11 and 12 in cooperation with valve springs 25 and 26.

The camshaft 14 includes a lower holder 27 that is integrally provided on the upper part of the cylinder head 2, and a bolt 2 that is attached to the lower holder 27.
It is rotatably supported by a cam holder 31 as a holder member constituted by an upper holder 2B which is connected to the upper holder 2B at 9.30. Furthermore, the lower holder 27 is integrally provided at the upper part of the cylinder head 2 so as to protrude upward within a plane that includes the center axis 13 of each cylinder 4 and is perpendicular to the axis of the camshaft 14 .

The exhaust side rocker arm shaft 16 is fixedly arranged to pass through each upper holder 28, and both ends of the exhaust side rocker arm shaft 16 are held by holders 32 attached to both ends 2a of the cylinder head 2 along the axial direction of the camshaft 14. supported.

The exhaust side rocker arm 18 is connected to the exhaust side rocker arm shaft 16 on the outside of each cam holder 31 along the axis of the camshaft 14.
The holders 32
A coil spring 33 that surrounds the exhaust rocker arm shaft 16 is interposed between the cam holder 31 and the exhaust rocker arm 18 and between the cam holder 31 and the exhaust rocker arm 18 in order to fix the axial position of each exhaust rocker arm 18. .

A support portion 35 that is thicker in the axial direction than a portion that supports the camshaft 14 and the exhaust rocker arm shaft 16 is integrally provided on the intake valve 11 side of the upper holder 28 . The lower holder 27 and the upper holder 28 that constitute the cam holder 31 are formed with an insertion hole 36 that is coaxially connected via a seal member 47 and extends obliquely from the outer side of the support portion 35 toward the center of the ceiling surface of the combustion chamber 6. Cylinder part 3
A screw hole 38 communicating with the center of the ceiling surface of the combustion chamber 6 is provided at the tip of the insertion hole 36 . An ignition plug P is inserted into the insertion hole 36, and the ignition plug P is screwed into the screw hole 38 so that its tip reaches the center of the ceiling surface of the combustion chamber 6.

In both outermost cylinders along the axis of the camshaft 14, the intake side rocker arm 17 is arranged on the inner side of the cylindrical part 37 along the axis of the camshaft 14; In the two cylinders on the side as well, the intake side rocker arm 17 is arranged inward of the cylindrical portion 37 along the axis of the camshaft 14. The intake rocker arm shaft 15 that pivotally supports these intake rocker arms 17 is connected to the support portions 35 of mutually adjacent cylinders.
fixedly arranged throughout the period. That is, one intake-side rocker arm shaft 15 is provided between the support portion 35 of the cylinder at both outer ends and the support portion 35 of the cylinder adjacent to the cylinder at the outer end on the inner side. One intake rocker arm shaft 15 extends between the two cylinder support parts 35.
is provided. In other words, the three intake side rocker arm shafts 1
5, the four intake side rocker arms 17 are swingably supported. Further, a coil spring 34 is interposed between each intake-side rocker arm 17 and the support portion 35 to fix the axial position of the intake-side rocker arm 17 (the coil spring 34 surrounds the intake-side rocker arm shaft 15).

The cylinder head 2 has a head cover 4 that covers the valve train.
0 is coupled to the head cover 40 via a seal member 39, and a pressing portion 42 that abuts the upper end of the cylindrical portion 37 via a seal member 41 is integrally provided on the head cover 40. A hole 43 that connects to the cylindrical portion 37 is bored in the pressing portion 42 .
3 is closed by a cap 45 provided on a cord 44 connected to the spark plug P so as to be openable and closable.

Next, the operation of this embodiment will be explained. When the camshaft 14 is rotationally driven in accordance with the operation of the engine, the intake side and exhaust side ports and the rocker arm 17.18 are rotated around the intake side and exhaust side rocker arm shafts 15.16. The valve spring 25,
26 to open and close the intake valve 11 and the exhaust valve 12 at predetermined timing.

At this time, since the spark plug P is arranged facing the center of the ceiling surface of the combustion chamber 6, the flame propagation distance from the ignition point to each peripheral edge of the combustion chamber 6 is approximately equal, so the combustion time is shortened and the output is high. It is possible to achieve this and prevent the occurrence of non-king, and it is not necessary to build up on the ceiling surface of the combustion chamber 6.

Furthermore, since the intake side rocker arm 17 is disposed inward from the cylindrical portion 37 at both outer ends along the axis of the camshaft 14,
Both ends 2a of the cylinder rod 2 along the axis of the camshaft 14
It is possible to shorten the distance between the cylinder part 37 and the cylinder part 37,
This can contribute to downsizing of the engine body E. In addition, the intake rocker arm shaft 15 is not provided commonly to each cylinder (but is provided as a necessary part and is divided into three pieces), which contributes to weight reduction.

FIG. 3 shows a second embodiment of the present invention, and parts corresponding to those in the first embodiment are given the same reference numerals.

The exhaust side Ronca arm shaft 16' is connected to the holder 32 and the cam holder 3 in both outermost cylinders along the axis of the camshaft 14.
It is provided across the cam holder 31 of the two cylinders along the axis of the camshaft 14. That is, the four exhaust rocker arms 18 are swingably supported by the three exhaust rocker arm shafts 16'.

Furthermore, in the two inner cylinders along the axis of the camshaft 14, the intake rocker arms 17 are arranged axially outward from the cylinder portion 37, and the intake rocker arms 17 are supported on the intake side. The rocker arm shaft 15' is provided between the support portion 35 of the outermost cylinder along the axis of the camshaft 14 and a cylinder adjacent to that cylinder on the inner side. That is, the four intake rocker arms 17 are swingably supported by the two intake rocker arm shafts 15'. Furthermore, a washcloth 48 is interposed between the intake side rocker arms 17 that are adjacent to each other.

According to this embodiment, in addition to achieving the same effects as the first embodiment, it is possible to further reduce the weight.

In the above embodiment, a case has been described in which the cylindrical portion 37 is provided on the intake valve 11 side, but it is also possible to provide the cylindrical portion 37 side on the cam holder 31 on the exhaust valve 12 side. Further, in the above embodiment, the camshaft 14 and the rocker arm shaft 15.16 were supported by the cam holder 31, but a holder member for supporting the rocker arm shaft 15.16 was provided separately from the cam holder that supported the camshaft 14. The present invention can also be applied to objects.

C0 Effects of the Invention As described above, according to the present invention, the ignition plug must be inserted into the center of the ceiling of the combustion chamber. A cylindrical part that forms an insertion hole that is tilted is provided integrally with the holder member, and in the outermost cylinder along the axial direction of the camshaft, the intake side or exhaust side rocker arm on the side where the cylindrical part is arranged is connected to the cam. Since the spark plug is placed inward of the cylindrical part along the axial direction of the shaft, the spark plug can be placed in the center of the ceiling surface of the combustion chamber to prevent knocking, and the cylindrical part is provided. As a result, the length of the cylinder head along the axial direction of the camshaft can be avoided, contributing to miniaturization.

[Brief explanation of the drawing]

Figures 1 and 2 show a first embodiment of the present invention, with Figure 1 being a longitudinal side view, Figure 2 being a plan view of Figure 1 with the head cover removed, and Figure 3 being a top view of Figure 1 with the head cover removed. FIG. 2 is a plan view corresponding to FIG. 2 of a second embodiment of the present invention. 6... Combustion chamber, 14... Camshaft, 15.15'...
・Intake side rocker arm axis, 16.16'...Exhaust side rocker arm axis, 17...Intake side rocker arm, 18・
...Exhaust side rocker arm, 31...Cam holder as a holder member, 36...Insertion hole, 37...Cylinder part, P
...Spark plug Figure 1 Z

Claims (1)

[Claims] The spark plug is placed facing the ceiling of the combustion chamber, and the intake side and exhaust side rocker arm shafts are respectively supported by holder members on both sides of a single camshaft that is rotatably placed above the combustion chamber. 1 per cylinder on the rocker arm shaft
An SOHC type in which an intake side rocker arm that interlocks and connects the two intake valves and camshafts is swingably supported, and an exhaust side rocker arm that interlocks and connects the exhaust valves and camshafts is supported on the exhaust side rocker arm shaft. In a multi-cylinder internal combustion engine, a cylinder that forms an insertion hole that connects to the center of a ceiling surface of a combustion chamber and tilts toward one of the intake valve and exhaust valve as it goes upward, in order to insert a spark plug into the center of the ceiling surface of a combustion chamber. In the outermost cylinder along the axial direction of the camshaft, the intake side or exhaust side rocker arm on the side where the cylindrical part is installed is attached to the cylindrical part along the axial direction of the camshaft. An SOHC type multi-cylinder internal combustion engine, characterized in that it is arranged on the inner side of the SOHC type internal combustion engine.