JPS6318113A - Sohc type muticylinder internal combustion engine - Google Patents

Abstract

PURPOSE:To simplify the structure, by integrally forming a holder member for supporting a cam shaft and rocker shafts with a cylindrical portion having a spark plug insert hole extending obliquely, and commonly supporting rocker arms on the side where the cylindrical portion is provided, between adjacent two cylinders. CONSTITUTION:In an engine having intake and exhaust valves adapted to be opened and closed through and exhaust rocker arms 17 and 18 by the rotation of a cam shaft 14, the cam shaft 14 is rotatably supported to cam holders 31 fixed to an upper portion of a cylinder head 2 by bolts 29 and 30. Each cam holder 31 is integrally formed with a cylindrical portion 37 having as insertion hole 36 communicated with a central portion of a ceiling surface of each combustion chamber and inclined to either of the suction or exhaust valve as extending upwardly. Between adjacent two cylinders, the rocker arms 17 on the side where the cylindrical portions 37 are provided are located between the adjacent cylindrical portions 37 in such a manner that the rocker arms 17 are commonly supported to rocker shafts 15 and 16 provided between the adjacent cam holders 31.

Description

Detailed Description of the Invention A1 Objective of the Invention (1) Industrial Field of Application The present invention is directed to a 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.

(2) Prior Art Conventionally, in SOHC multi-cylinder internal combustion engines, the spark plug is generally located at a position offset from the center of the ceiling surface of the combustion chamber.

(3) Problems that the invention attempts to solve However, the above-mentioned conventional type is prone to knocking.

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 has been made in view of the above circumstances, and the present invention solves the above problems by arranging the spark plug in the center of the combustion chamber, and provides an SOHC with an increased degree of freedom in arrangement.
The purpose is to provide a 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 forming an insertion hole tilted to one side is integrally provided in the holder member, and between two mutually adjacent cylinders, the rocker arm on the side where the cylindrical part is disposed is connected to the holder member. The rocker arm shafts are respectively disposed between the cylindrical portions of both cylinders so as to be commonly supported by a rocker arm shaft provided between the holder members.

(2) Function The spark plug is disposed through the insertion hole facing the center of the ceiling surface of the combustion chamber, thereby preventing the occurrence of knocking. Furthermore, between two mutually adjacent cylinders, the rocker arm on the side where the cylindrical portion is disposed is placed between the cylindrical portions of both cylinders, and the rocker arm shaft is provided between the holder members of both cylinders, so that the rocker arm shaft and the cylinder The cylindrical portion can be brought close to the camshaft side without interfering with the camshaft. Moreover, the rocker arm shaft can be omitted in the redundant part, thereby reducing the weight.

(3) Example Hereinafter, one example in which the present invention is applied to a SOHC type four-cylinder internal combustion engine will be explained with reference to the drawings.
In the figures and FIG.
The cylinder head 2 is polymerized and bonded via the cylinder head 2,
Pistons 5 are slidably connected to four cylinders 4 bored in the cylinder block 1, respectively. A combustion chamber 6 is defined by the cylinder block 1, cylinder head 2, and piston 5, and the ceiling surface of the combustion chamber 6 is formed in the shape of a roof that slopes toward each other.

One intake valve lower is opened on one side of the ceiling surface of each combustion chamber 6, and an intake port 9 communicating with this 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).

Further, 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 an exhaust manifold (not shown) through an exhaust port 10 bored in the cylinder head 2. connected to.

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. Moreover, the intake valve 11 and the exhaust valve 12 are arranged on both sides of the central axis 130 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
At a position above the camshaft 14 between the intake valve 11 and the intake valve 11, two intake-side rocker arm shafts 15 for all cylinders
The camshaft 14 and the exhaust valve 12 are fixedly arranged in parallel with each other.
Three exhaust-side rocker arm shafts 16 for all cylinders are fixedly arranged parallel to the camshaft 14 at positions above the camshaft 14 between the camshaft 14 and the camshaft 14 .

One intake-side rocker arm 17 per cylinder is swingably supported on each intake-side port 7 arm shaft 15, and the outer end of each intake-side rocker arm 17 is attached to each intake valve 11 via an adjuster 19. A slipper surface 20 abutting the upper end and provided at each inner end is in sliding contact with an intake side valve operating cam 21 of the camshaft 14 .

Further, one exhaust side rocker arm 18 per cylinder is swingably supported on the exhaust side port 7 arm shaft 16, and the outer end of each rocker arm 18 is connected to the upper end 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 port V arm 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 28 connected 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 provided between the holder 32 attached to the end 2a of the cylinder head 2 and the cam holder 31 in the cylinder at the outer end of the rain volume along the axis of the camshaft 14, and extends along the axis of the camshaft 14. In the two inner cylinders, an exhaust rocker arm shaft 16 is provided between the cam holders 31 of both cylinders. That is, the four exhaust rocker arms 18 are swingably supported by the three exhaust rocker arm shafts 16.

Further, a coil spring 33 surrounding the exhaust rocker arm shaft 16 is interposed between the holder 32, the exhaust side port 7 arm 18, and the two exhaust side rocker arms 17, and these coil springs 33 cause each exhaust side rocker arm 17 to The axial position of is fixed.

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 upper holder 28 and the lower holder 27 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 . A spark plug P is inserted into the insertion hole 36, and the spark plug P is hinged to the screw hole 38 with its tip facing the center of the ceiling surface of the combustion chamber 6.

In the cylinder at the outer end of the rain volume 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, the intake rocker arm 17 is arranged on the outer side of the cylindrical portion 37 along the axis of the camshaft 14. The intake side opening hook 7-arm shaft 15 that pivotally supports these intake side 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 outer end 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, web washers 48 are interposed between the intake side rocker arms 17 that are adjacent to each other.

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, to explain the operation of this embodiment, when the camshaft 14 is rotationally driven in accordance with the operation of the engine, the intake side and exhaust side rocker arms 17.1i<the intake side and exhaust side ports/7 arm shafts 15.16 swings around 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 placed 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, and therefore the combustion time is shortened to the minimum. High output can be achieved, knocking can be prevented, and there is no need to build up on the ceiling surface of the combustion chamber 6.

In addition, since the intake rocker arm shaft 15 is provided between the cam holders 31 of adjacent cylinders, interference between the cylindrical portion 37 and the intake rocker arm shaft 15 can be avoided, and the cylindrical portion 37 can be brought closer to the camshaft 14 side. This increases the degree of freedom in arrangement.

Furthermore, since the intake side rocker arm 17 is disposed inwardly from the cylindrical portion 37 at both outer ends along the axis of the camshaft 14, both ends of the cylinder head 2 along the axis of the camshaft 14
It is possible to shorten the distance between a and the cylindrical portion 37, which contributes to downsizing of the engine body E.

Furthermore, the intake rocker arm shaft 15 is not provided commonly to each cylinder, but is provided as a necessary part and is divided into two pieces, which contributes to weight reduction.

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 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 portion forming an insertion hole inclined to the holder member is integrally provided with the holder member, and between two mutually adjacent cylinders, the rocker arm on the side where the cylindrical portion is disposed is provided between the holder members of both cylinders. The spark plugs should be commonly supported by the rocker arm shafts located between the two cylinders, so the spark plugs should be placed in the center of the ceiling of the combustion chamber to prevent kinging. At the same time, it is possible to bring the cylindrical part closer to the camshaft side, increasing the degree of freedom in arrangement.Furthermore, the rocker arms on the side where the cylindrical part is installed can be moved between adjacent cylinders. Since the rocker arms are placed close to each other and supported in common by the rocker arm shaft, the rocker arm shaft is omitted in unnecessary parts, and the rocker arm is supported by the minimum necessary rocker arm shaft, reducing weight. It will be planned.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIG. 1 is a longitudinal sectional side view, and FIG. 2 is a side view of the first embodiment with the head cover removed.
FIG. 6... Combustion chamber, 14... Camshaft, 15... Intake side rocker arm shaft, 16... Exhaust side port 7 rocker arm shaft, 1
7...Intake side rocker arm, 18...Exhaust side rocker arm, 31...Cam holder as a holder member, 3
6...Insertion hole, 37...Cylinder part, P...Spark plug

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. A section is provided integrally with the holder member, and between two mutually adjacent cylinders, the rocker arm on the side where the cylinder section is disposed is commonly supported by a rocker arm shaft provided between the holder members of both cylinders. An SOHC type multi-cylinder internal combustion engine characterized in that the SOHC type multi-cylinder internal combustion engine is arranged between the cylindrical portions of both cylinders.