JPH0116982B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cylinder head in an engine having multiple V-type or horizontally opposed intake valves to which a plug is attached from the cam chain chamber side.

In V-type or horizontally opposed engines, in order to make effective use of space and make the engine more compact, camshaft drive sprockets are generally fixed to both ends of the crankshaft, etc., and the sprockets are connected to each other via the sprockets and cam chain. The camshaft of the cylinder is driven.

On the other hand, in the case of an engine with multiple valves on the intake side, if the spark plug is installed from the cam chain side to improve maintenance, the spark plug will inevitably be positioned on the exhaust valve side.

Therefore, as shown in FIGS. 8 and 9, in a V-type engine, for example, camshaft driving sprockets 102, 1 at both ends of the crankshaft 101, etc.
The cam chains 104 and 105 that connect 03 are:
The camshafts 11 and 11 are respectively wound around a driven sprocket 107 of the front cylinder head 106 and a driven sprocket 109 of the rear cylinder head 108.
The cylinder heads 106, 108 are configured to drive the respective cylinder heads 106, 112 in accordance with the mounting positions of the camshaft driving sprockets 102, 103.
The cam chain chambers 113 and 114 are in opposite directions.

The plugs 121 and 122 installed from the cam chain chamber 113 and 114 sides are
1,122 to each cylinder head 10
6, toward the center of 108, and plug 12
The rear end of 1,122 is the cam chain 104,105
Tight sides 104a, 105a and slack side 10
4b, 105b, different angles θ from the left-right center lines 106a, 108a of the cylinder heads 106, 108, respectively.
The plugs 121 and 122 must be installed with an angle of 1 and θ2. As this angle θ2 becomes smaller, the tip position of the plug 122 shifts more toward the intake hole from the optimum position between the exhaust hole and the intake hole, which is undesirable from the viewpoint of improving the combustion efficiency of the engine.

In addition, two types of cylinder heads 106 and 1 are available, the only difference being the mounting angle of the plugs 121 and 122.
08 had to be manufactured individually, and it was desired that the cylinder heads 106 and 108 be made common.

Therefore, by making the mounting angles θ1 and θ2 of the plugs 121 and 122 equal, both cylinder heads 10
When trying to share 6,108, plug 12
1,122 and the cam chains 104, 105, the driven sprockets 107, 109
etc. must be made larger, and the cylinder head 10
A problem arises in that 6, 108, etc. become larger.

The present invention was devised to solve these problems, and its purpose is to install a plug on the cam chain chamber side.
The opening position of the combustion chamber is set at the optimum position between the intake and exhaust holes, and by eliminating interference with the cam chain, both cylinder heads can be shared while ensuring engine performance.

In order to achieve the above object, the present invention provides a multi-valve overhead cam type cross-flow engine having a cam chain chamber on one side, in which the number of intake holes is greater than the number of exhaust holes. In addition to providing spark plugs in the opposing spaces, the combustion chamber opening of the spark plug on the opposite side of the cam chain chamber and the opening of the spark plug on the cam chain chamber side are connected to the center line of the cylinder passing through the center of the exhaust hole. The spark plug is arranged approximately symmetrically with respect to the cam chain chamber, and the connecting end of the ignition plug on the cam chain chamber side to the cap is disposed toward the approximate center of the cam chain chamber.

A preferred embodiment of the present invention will be described below with reference to the accompanying drawings.

Fig. 1 is a side view of a motorcycle equipped with a V-type engine, Fig. 2 is a sectional side view of the main parts of the engine, Fig. 3 is a sectional view taken along the line shown in Fig. 2, and Fig. 4 is an enlarged sectional view of the main parts. , FIG. 5 is a plan view showing the installed state of the plug taken along the line in FIG. 2, FIG. 6 is a bottom view of the cylinder head, and FIG. 7 is a sectional view taken along the line in FIG. 6.

A head tube 3 is provided at the front end of the frame 2 of the motorcycle 1, and a front wheel 4 is attached to the head tube 3.
A front fork 5 supporting the front fork 5 is supported so as to be freely steerable, and a handle 7 is provided on the top bridge 6.

The frame 2 includes a main pipe 2a extending rearward from the rear upper part of the head tube 3, a down tube 2b hanging downward from the rear lower part of the head tube 3, and a down tube blower 2e extending rearward from the lower end of the down tube 2b. , a center tube 2c that extends forward and upward from the rear end of the down tube blower 2e and is joined to the rear end of the main pipe 2a, a seat rail 2d that extends rearward of the main pipe 2a, and the like.

The down tube blower 2e, center tube 2c, etc. after the down tube tube 2b, and the main pipe 2a are provided on the left and right sides, and the combustion tank 8 is mounted across the main pipe 2a of the frame 2, and the combustion tank 8 is mounted on the seat rail 2d. A seat 9 is mounted on the seat 9, and a rear wheel 12 is supported via a rear fork 11 pivotally extended rearward from the lower part of the center tube 2c. 13 are interposed.

The engine 1 is located in a space surrounded by the main pipe 2a, down tube 2b, down tube blower 2e, and center tube 2c of the frame 2.
4, and the engine 14 has a narrow side angle in the example.
Shows a 45° V-type two-cylinder engine.

The engine 14 has front and rear cylinders 15,1
6, crankcase 17, etc., and the front cylinder 15 has a cam chain chamber 1 on the left side of the vehicle body.
8a, the rear cylinder 16 is provided with a cam chain chamber 18b on the right side of the vehicle body, and the cylinder holes of the front and rear cylinders 15 and 16 are offset from the vehicle center line in the left and right directions, respectively. .

Camshaft drive sprockets 22 and 23 are attached to both ends of the crankshaft 21 disposed in the crankcase 17, respectively, and the front cylinder 15
The driven sprocket 26 of the camshaft 25 disposed on the cylinder head 24 and the left camshaft driving sprocket 22 are connected to the chain chamber 18a.
connected by a cam chain 27 passing through the
The driven sprocket 33 of the camshaft 32 disposed on the cylinder head 31 of the rear cylinder 16 and the right camshaft driving sprocket 23 are connected by a cam chain 34 passing within the chain chamber 18b.

Cylinder head 24 of the front cylinder 15
The cylinder head 31 and the cylinder head 31 of the rear cylinder 16 have the same shape and structure, and are attached to the respective cylinder bodies 35 and 36 so as to be horizontally rotated by 180 degrees with respect to each other.

To explain the rear cylinder 16 for convenience, the cylinder head 31 is formed with two intake holes 41 and 42 and one exhaust hole 43, as shown in FIG. Plug screw holes 53, 49 are provided so that the tips of the plugs 44, 45 are located in the spaces facing each other. The opening positions of the plug screw holes 53 and 49 are arranged approximately symmetrically with respect to the center line of the cylinder 16 passing through the center of the exhaust hole 43.

Furthermore, in order to attach the rear end of the plug 44, which is attached from the cam chain chamber 18b side, to approximately the center of the cam chain chamber 18b, the axis 46 of this plug 44 is aligned from the top and bottom of the cylinder head 31. When viewed, the intersection of the extension line of the axis 46 and the longitudinal center line 55 of the combustion chamber 54 is slightly offset from the center 56 of the combustion chamber 54 toward the exhaust hole 43, and is located at the outer end 46b of the axis 46. is slightly offset toward the exhaust hole 43 from the lateral center line 57 of the combustion chamber 54 (the center line of the combustion chamber 54 substantially parallel to the crankshaft 21).

In this embodiment, the axial center 46 is inclined at about 3 degrees with respect to the lateral center line 57, and when viewed from the lateral direction of the cylinder head 31, as shown in FIG. The extension line is the center 56 of the combustion chamber 54
The outer end 46b of the shaft center 46 is formed to be slightly higher than the inner end. and,
A guide hole 47, a sleeve threaded hole 48, and a plug threaded hole 49 are formed along this axis 46, respectively.

The mounting axis 51 of the other plug 45 is located at the sixth
As shown in the figure, when the cylinder head 31 is viewed from above and below, the extension line of the axis 51 approximately coincides with the center 56 of the combustion chamber 54, and the outer end of the axis 51 is connected to the exhaust hole 43.
It is deviated to the side. In addition, the cylinder head 31
When viewed from the lateral direction, the extension line of the shaft center 51 intersects with the lower surface 31a of the cylinder head at a position offset from the center 56 of the combustion chamber 54 toward the outer end of the shaft center 51, and the outer end of the shaft center 51 Located higher than the end, the axis 51
The angle between the cylinder head and the lower surface 31a of the cylinder head is approximately 60° or less in consideration of the spark plug device.

Then, along this axis 51, a guide hole 52,
Plug screw holes 53 are formed respectively.

The sleeve 61 is inserted into the guide hole 47 and the sleeve threaded hole 48, and the plug 4 is inserted into the plug threaded hole 49.
A cap 62 is fitted to the rear of the plug 44, and the outer end of the cap 62 is supported by the outer end of the sleeve 61 via a seal member 63.
Further, a plug 45 is attached to the guide hole 52 and the plug screw hole 53.

In the drawing, 71 is a carburetor, 72 is a cooling water pipe, and a rubber member 73 is fitted to the portion of the cooling water pipe 72 facing the cylinder body 35, and the rubber member 73 prevents vibration of the cooling water pipe 72. ing.

The present invention is configured as described above, and the plug 44, which is attached from the cam chain chamber 18b side, is inserted between the tension side 34a and the slack side 43b of the cam chain 34, and between the tension side 34a or the slack side 34b as appropriate.
Since the plug 44 is arranged so as to be inclined in the direction, when the cylinder head 31 is attached to the front cylinder 15 as shown in FIG. without moving the cylinder head 3 to the rear cylinder 16.
1 is installed, the plug 44 does not interfere with the tight side 34a and slack side 34b of the cam chain 34, as shown by the imaginary line, and therefore the cylinder head 3
1 can be made compact and can be used commonly by the front cylinder 15 and the rear cylinder 16.

Furthermore, as shown in FIG. 4, the installation and removal of both the plugs 44 and 45 can be done easily and quickly without any tools or the like interfering with the main pipes 2a, 2a.

In the embodiment, a V-type engine has been described, but the present invention is also applicable to a horizontally opposed engine.

As is clear from the above description, the present invention allows the plug to be installed from the cam chain chamber side, and the rear end of the plug to be installed approximately at the center of the cam chain chamber while maintaining the optimum opening position of the combustion chamber. Since the ignition plug is installed so that the tip of the ignition plug faces the center of the cylinder head and the rear end of the ignition plug does not interfere with the cam chain, the tip of the ignition plug will move from the exhaust side to the intake side. In addition, the rear end of the spark plug is placed approximately in the center of the cam chain chamber, so it does not interfere with either the tight or slack side of the cam chain. Two cylinder heads of a V-type engine can be shared.

[Brief explanation of drawings]

Fig. 1 is a side view of a motorcycle equipped with a V-type engine, Fig. 2 is a sectional side view of the main parts of the engine, Fig. 3 is a sectional view taken along the line shown in Fig. 2, and Fig. 4 is an enlarged sectional view of the main parts. , FIG. 5 is a plan view showing the installed state of the plug in the section taken along the line in FIG. 2, FIG. 6 is a bottom view of the cylinder head, FIG. 7 is a sectional view taken along the line in FIG. 6, and FIGS. Figure 8 explains a conventional cylinder head, and Figure 8 is a schematic side view of the engine.
FIG. 9 is a diagram showing the relationship between the front and rear cylinder heads when FIG. 8 is viewed from above. In the drawing, 15 is a front cylinder, 16 is a rear cylinder, 18 is a cam chain chamber, 27, 3
3 is a cam chain, 41 and 42 are intake holes, 43 is an exhaust hole, 44 and 45 are spark plugs, 49
53 is the plug screw hole corresponding to the opening of the combustion chamber of the ignition plug on the side of the cam chain chamber, 53 is the plug screw hole corresponding to the opening of the combustion chamber of the ignition plug on the side opposite to the cam chain chamber, and 55 is the center of the exhaust hole. It is the center line of the cylinder that it passes through.

Claims (1)

[Claims] 1. In a V-type or horizontally opposed multi-valve overhead cam type cross-flow engine that is equipped with a cam chain chamber on one side and has more intake holes than exhaust holes, Spark plugs are provided in the opposing spaces, and the opening of the combustion chamber of the spark plug on the opposite side of the cam chain chamber and the opening of the spark plug on the side of the cam chain chamber are connected to a cylinder passing through the center of the exhaust hole. The spark plug is arranged approximately symmetrically with respect to the center line of the cam chain chamber, and the connecting end of the ignition plug on the side of the cam chain chamber to the cap is arranged toward the approximate center of the cam chain chamber. cylinder head.