JPH11315774A - Sparkplug extension structure of air-cooled single cylinder engine for motorcycle and extension method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sparkplug extension structure of a new structure which permits the extension of a new sparkplug in addition to the existing sparkplug of an air-cooled single cylinder engine for a motorcycle, as well as a new sparkplug extension method. SOLUTION: This extension structure of a sparkplug eliminates the fin for cooling on the wall outside surface which forms the camshaft system housing chamber on the right outside of a cylinder head. An insertion hole 6 for the extension plug is made which faces the top dead center surface center of the piston in the combustion chamber from this outside surface and which passes through the wall portion which forms the camshaft system housing chamber and the wall portion of the combustion chamber. Then, an extension plug sleeve 7, which connects the combustion chamber with the outside wall of the camshaft system housing chamber, is inserted and integrated with the engine body such that the sparkplug is separated from the inside of the cam drive system housing chamber. Meanwhile, a sparkplug 2 for extension is detachably connected and attached to this extension plug sleeve 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine structure for improving the output performance of an air-cooled single-cylinder engine for motorcycles, which is widely used for driving on general public roads and racing circuits, and to processing and assembly of the engine. In particular, it is an object of the present invention to provide an additional structure and a method for adding a spark plug of an air-cooled single-cylinder engine for a motorcycle having a novel structure for improving the combustion efficiency of gasoline.

[0002]

2. Description of the Related Art Motorcycles produced in Japan have been proven in high performance and reliability because each manufacturer has participated in various races and achieved high results. Is expected to continue to lead the world with the development of new world-class technologies. Despite this favorable technical environment, the demand for motorcycles has not been seen in Japan as automobiles have spread due to the spread of automobiles. With the increasing tendency to enjoy and motor sports being actively performed, the demand has been resurrected again, and it has recently been manufactured and sold to meet those needs. Some of the motorcycles, which utilize the technology accumulated so far, are not just practical vehicles for driving on public roads, but also have a large number of motorcycles with high performance so that they can participate in the race as it is, Has attracted the attention of many users.

[0003] Among various categories of motorcycles such as off-road and on-road models, the air-cooled single-cylinder engine has a simpler structure than a water-cooled engine or a multi-cylinder engine, and has a smaller width. It is small in size and satisfies the conditions necessary to enhance the turning performance of a motorcycle that is lightweight, and it is easy to disassemble and assemble.
There are many popular parts, and various parts are prepared in the market, and individual users can perform their own tuning and remodeling according to their preference, so they are becoming a good material as a hobby object, Recently, there are many races competing for the tuned performance of motorcycles equipped with the same vehicle type or the same type of engine in many places, and there are many users who desire further improvement in output.

For example, a Yamaha SR400 / 500 (trade name) shown in a side view of a motorcycle shown in FIG. 8 is a motorcycle equipped with an OHC air-cooled single-cylinder engine, which is the most basic configuration, and has a rear side of the engine body 1. Carburetor 11 provided on the engine body 1, is burned by a spark plug 2 provided on the left side of the engine body 1, and is exhausted from an exhaust pipe 12 through a front exhaust manifold. Is constructed as shown in an exploded perspective view of the cylinder in FIG.

In general, in order to improve the performance of a single-cylinder engine, parts such as a carburetor, an intake / exhaust valve, and a camshaft are reduced in weight, changed to a durable material, or subjected to rework to increase the height. In addition to tuning to accuracy, mounting an oil cooler and improving the performance of a muffler are being performed. However, in order to further increase the combustion efficiency, an additional spark plug 2 is required to improve the performance. It is desirable to increase the output. In fact, it is widely known that other types of engines (for example, a water-cooled multi-cylinder engine) which adopt a twin plug structure to increase the combustion efficiency and improve the output are already widely known. It is as it is.

However, an OHC air-cooled single-cylinder engine is
An existing ignition plug 2 is provided on the left side wall of the cylinder head 4, an intake manifold is provided on a rear side wall, an exhaust manifold is formed on a front side wall, and a sprocket for a camshaft is provided on a right side wall. A cam drive system accommodating chamber 13 for accommodating the engine oil and the cam chain 52 is provided, and an intake / exhaust valve and a camshaft 5 (not shown) are provided above the cylinder head 4. Since it is provided, it is a structure in which it is impossible to add a new spark plug also on the peripheral side wall of the cylinder head 4 and the upper side of the combustion chamber.

The present invention focuses on the necessity of a new technology that allows the addition of a new spark plug in addition to the existing spark plug in the above-described air-cooled single-cylinder engine for motorcycles. As a result of repeating trial and error over a long period of time for the attachment structure and its processing and assembly method, as well as conducting numerous trial manufactures and experiments, this time, finally, a new structure of an air-cooled single-cylinder engine ignition plug extension for motorcycles, The present invention has succeeded in developing and realizing a new spark plug adding method. Hereinafter, the configuration will be described in detail together with an embodiment which is representative of the present invention shown in the drawings.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS As clearly understood from the embodiments of the present invention shown in the drawings, the spark plug extension structure of the air-cooled single cylinder engine for a motorcycle included in the present invention is basically as follows. It consists of a simple configuration. That is, an engine in an OHC air-cooled single-cylinder engine in which a spark plug is mounted on the left side wall of a cylinder head and a cam drive system accommodating chamber in which a camshaft sprocket and a cam chain are built is formed in a right side wall across a combustion chamber. On the right outside of the cylinder head that forms part of the body,
A part or all of the air-cooling fins at a predetermined portion of the outer surface of the cam drive system housing chamber forming wall portion are cut off, and the direction from the exposed outer surface predetermined position to the center of the piston top dead center in the combustion chamber is obtained. The cam drive system housing chamber forming wall portion, the cam drive system housing chamber, between the cam chains below the sprocket for the camshaft, and through the combustion chamber wall portion, are provided with additional plug insertion holes, and the additional plug A sleeve for an additional plug, which is formed in a substantially cylindrical shape, connects the combustion chamber and a predetermined position on the outer surface of the wall on which the cam drive system housing chamber is formed so as to have a structure isolated from the cam drive system housing chamber. An additional spark plug for an air-cooled single-cylinder engine for motorcycles, which is inserted, fixed and integrated with the engine body by an appropriate coupling structure, and detachably screwed and mounted with an additional spark plug to the additional plug sleeve. It is an elephant.

An air-cooled single cylinder engine for a motorcycle uses gasoline employing an overhead camshaft system,
A four-stroke cycle with a vertical cylinder, an intake manifold at the rear of the combustion chamber, an exhaust manifold at the front, an existing spark plug on the left, and a camshaft sprocket and cam chain on the right. The cam drive system accommodating chamber is provided, and specifically, is set to a displacement of 400 CC or 500 CC.

The cylinder head has a bottom surface joined to the top surface of the cylinder block via a gasket and connected by a plurality of bolts, and has a central portion facing the top of the cylinder formed in the cylinder block. A combustion chamber is formed at a lower portion, and one camshaft, a pair of rocker arms, and an intake / exhaust valve are configured to be mounted above the combustion chamber. A plug mounting hole into which the spark plug is screwed and mounted is formed, and a cam drive system housing chamber for housing a camshaft sprocket and a cam chain is formed in the right side wall.

The extension plug insertion hole serves as a fixing hole for inserting and fixing the extension plug sleeve. The extension hole is located between the cam chains located below the sprocket for the cam shaft, and the cam drive is provided. It must be perforated so as to concentrically penetrate the outer wall of the system housing chamber and the side wall of the combustion chamber, for example, the outer wall of the cam drive system housing chamber or the side wall of the combustion chamber, or Female threads may be formed on both the outer wall of the cam drive system accommodating chamber and the side wall of the combustion chamber, and an additional plug sleeve to be inserted may be screwed and fixed, or may be welded. Alternatively, a structure may be adopted in which a seat surface having a metal adhesive or a plurality of screw holes is formed, a flange portion is formed on the side of the additional plug sleeve, and the flange portion is joined by screws.

The extension plug sleeve functions as a mounting seat hole for securely fixing the extension spark plug at an appropriate position, and also functions as a partition wall surface for isolating the extension spark plug from the cam drive system accommodating chamber. It is formed in a cylindrical shape to which an additional spark plug can be attached,
A female screw portion for screwing and fixing the additional spark plug must be formed on the inner peripheral surface.For example, a female screw portion is formed in an additional plug insertion hole located in the side wall portion of the combustion chamber. If so, a male thread is formed on the outer peripheral wall at the tip end of the additional plug sleeve that is inserted into the female thread to ensure the isolation structure between the combustion chamber and the cam drive system housing chamber. Further, it is also possible to provide an oil leakage prevention collar for preventing the engine oil from leaking, which is further annularly mounted on the outer periphery of the additional plug sleeve in the cam drive system accommodating chamber. The collar is preferably fixed to the engine body by a metal adhesive having excellent oil and heat resistance, welding or brazing, or a bolted structure.

The extension plug sleeve is arranged so that its axis is inclined at an angle of 16 degrees upward from the center of the piston top dead center in the combustion chamber and crosses the center of the piston top dead center in the combustion chamber. If it is tilted beyond 16 degrees 30 minutes, it will interfere with the camshaft sprocket, making it impossible to obtain normal engine operation, and tilting more than 15 degrees 30 minutes. Is small, it interferes with the upper surface side of the cylinder block.
It must be mounted so that it tilts upward at an angle regulated within the range of 30 degrees to 16 degrees 30 minutes.

The extension plug sleeve is arranged such that its axis is inclined at an angle of 5 degrees toward the exhaust side in the plane of the piston top dead center and crosses the center of the piston top dead center in the combustion chamber. Desirably, if it exceeds 5 degrees 30 minutes, the tip of the additional ignition plug will interfere with the exhaust valve, or the outer peripheral surface of the additional plug sleeve will interfere with the inner edge of the cam chain located on the exhaust side. If the angle is smaller than 4 degrees 30 minutes, the tip of the additional ignition plug may interfere with the intake valve, or the outer peripheral surface of the additional plug sleeve may be in contact with the inner edge of the cam chain located on the intake side. Since there is a possibility of causing interference, it is necessary to arrange at an angle of 4 degrees 30 minutes to 5 degrees 30 minutes toward the exhaust side at least in the plane of the piston top dead center.

The extension plug sleeve is 33.5 to 35.5 m from the inner edge of the cam chain located on the intake side.
m and 25.5 to 27.5 from the inner edge of the cam chain located on the exhaust side of the exhaust valve. The tip may interfere with any of the intake and exhaust valves, or the outer peripheral wall surface of the additional plug sleeve may interfere with the cam chain running during driving of the engine.

Further, it is necessary that the center of the additional plug sleeve is located 69.5 to 70.5 mm below the center of the camshaft. Interference occurs, and if it is located below this, there is a high possibility that it will interfere with the cylinder block side. In addition,
The specific arrangement dimensions of the additional plug sleeve up to the above are numerical values assuming that the outer diameter of the additional plug sleeve is set to 35 mm.
When the outer diameter is smaller than 5 mm, it is needless to say that the setting range can be expanded correspondingly, and the dimensional difference of only several mm or several degrees can be used to increase the spark plug extension structure of the present invention. Needless to say, the scope of the basic configuration is not excluded.

The oil leakage preventing collar functions not only as a packing for preventing oil leakage, but also as a fixing metal for fixing the additional plug sleeve to the engine body. An annular rubber gasket that fits outside can also be provided. For example, a cylindrical shape is fixed to the right wall surface in the cam drive system accommodating chamber, and a total of three gaskets are arranged at every 120 degrees penetrating the cylindrical wall surface. It is also possible to have a configuration in which the adjusting screw is provided, and by adjusting the adjusting screw forward and backward, the axial position of the inserted additional plug sleeve is finely adjusted vertically and horizontally.

The additional spark plug is a plug that is newly added in addition to the existing spark plug inserted at the time of factory production of the engine, and has substantially the same performance as the existing plug, or has the same performance. An ignition plug having
It goes without saying that various types of ignition plugs, such as a spark plug employing a special lateral electrode such as a pole type or a creepage type, and a burnt type, a cold type, or a platinum plug having excellent durability are used.

[0019]

[Related Invention] In connection with the above-described structure for adding a spark plug of an air-cooled single-cylinder engine for a motorcycle, the present invention also includes a new method for adding a spark plug, and the gist thereof is basically as follows. belongs to. That is, an ignition plug is mounted on the left side wall of the cylinder head, and a cam drive system accommodating chamber in which a camshaft sprocket and a cam chain are built is formed in the right side wall across the combustion chamber.
In the HC air-cooled single-cylinder engine, a part or all of the air-cooling fins at a predetermined portion of the outer surface of the wall on which the cam drive system housing chamber is formed is cut off on the right outer side of the cylinder head forming a part of the engine body, and the exposed outer rim is exposed. A direction from a predetermined position of the side surface toward the center of the piston top dead center in the combustion chamber, the cam drive system housing chamber forming wall portion, between the cam chains below the camshaft sprocket in the cam drive system housing chamber, and the combustion chamber. An insertion hole for an additional plug penetrating the wall portion is formed, and a female screw portion is engraved inside a tip side portion of the insertion hole for the additional plug corresponding to the combustion chamber wall portion. An external thread is formed on the tip end side of the hole, and it is formed in a substantially cylindrical shape that connects the combustion chamber and the cam drive system housing chamber forming wall outer surface at a predetermined position so as to be isolated from the cam drive system housing chamber. Extension plug The sleeve is inserted and screwed in. Further, the collar for preventing oil leakage provided in the cam drive system accommodating chamber is fitted, fixed and integrated with the engine body, and the additional ignition plug is detachably attached to the additional plug sleeve. This is a method for adding a spark plug of an air-cooled single cylinder engine for a motorcycle to be screwed and mounted.

The method of adding a spark plug of an air-cooled single-cylinder engine for a motorcycle is based on the fact that a new spark plug is added to an OHC air-cooled single-cylinder engine completed by factory production in addition to the existing one spark plug. It is a method of remodeling an engine with a total of two spark plugs,
In particular, a sleeve for an additional plug is attached to the side of the engine body having a cam drive system accommodating chamber where it is impossible to add an ignition plug as it is, and the additional ignition plug is detachably attached to this. It is.

Therefore, in order to carry out the method of adding a spark plug, the engine is disassembled, the cylinder head is removed, a hole for inserting the additional plug is formed, and a sleeve for the additional plug is inserted and fixed. Then, after reassembling the engine, install the additional spark plug, or obtain a new cylinder head separately from the one attached to the engine, and , And the sleeve for the additional plug is inserted and fixed, and then the processed cylinder head and the existing cylinder head are exchanged and assembled, and the additional plug can be attached and added.

Further, when removing the cylinder head,
It is of course possible to replace or rework various parts such as camshafts, sprockets for camshafts, cam chains, intake / exhaust valves, rocker arms, gaskets, etc., as well as perform engine adjustment and overhaul work in parallel. It is. In the following, the structure of the present invention will be described in detail, together with the embodiment shown in the drawings.

[0023]

FIG. 2 is a perspective view showing an expanded state of the spark plug of FIG. 1, and FIG.
3 is a vertical cross-sectional view of the expanded state of the spark plug, FIG. 3 is a bottom view of the expanded cylinder head of the spark plug, FIG. 4 is a side view of the expanded state of the spark plug, FIG. The case shown in the front view of the oil leakage prevention collar 6 and the longitudinal cross-sectional view of the oil leakage prevention collar in FIG. 7 is an embodiment of the spark plug extension structure of the air-cooled single cylinder engine included in the present invention. A new ignition plug 2 is provided in the right side wall of the engine body 1 in which the cam drive system accommodating chamber 13 of the OHC air-cooled single cylinder engine is provided.

Cam drive system housing chamber 1 of cylinder head 4
The air-cooling fins 14, 14,... Formed over a range corresponding to the combustion chamber 41 on the right side wall portion where 3 is formed.
A hole for an additional plug penetrating the cam drive system accommodating chamber 13 and the peripheral wall of the combustion chamber 41 is formed in the exposed side wall surface by cutting off a part of the plug hole. A female thread 61 with a pitch of 1.25 mm is engraved on the distal end portion corresponding to the peripheral wall portion of the combustion chamber 41, and M14, a pitch of 1.2 on the distal end side with respect to the insertion hole 6 for the additional plug.
A cylindrical additional plug sleeve 7 having a 5 mm male screw portion 71 is inserted and screwed so as to be arranged between the cam chains 52 located below the camshaft sprocket 51.

The extension plug sleeve 7 has a larger diameter at the rear end located outside and a smaller diameter at the tip end located at the combustion chamber 41 side, and has the extension plug 2 attached and detached from the rear end inside. M10 freely inserted and screwed, pitch 1.
A female screw portion 72 of 25 mm is formed, and a hexagonal head portion 73 having a hexagonal diameter and rotatable by a wrench is formed on the outer peripheral portion on the rear end side. The outer diameter dimension A of the rear end portion is 35 m.
m, the inner diameter dimension B is 22 mm, the thickness C is 6.5 mm,
The base of the male screw portion 71 on the distal end side is formed as a bearing surface portion having a thickness D of about 3 mm, and has a structure that can withstand screw tightening. Further, the distal end portion of the male screw portion 71 is inserted into and fixed to the combustion chamber. A cutout shape is provided so as to match the outer peripheral wall shape of 41.

On the outer peripheral wall portion of the additional plug sleeve 7 located in the cam drive system accommodating chamber 13, an oil leakage prevention collar 8 formed annularly and having a rubber annular gasket 81 is provided all around. And a total of three position adjusting screws 82, 82, 82 are screwed toward the center every 120 degrees around the oil leakage preventing collar 8. A peripheral portion facing the inner wall surface of the cam drive system accommodating chamber 13 located on the upper and right outer sides is joined and fixed to the cylinder head 4 with a heat-resistant metal adhesive so as to maintain a closed state, and a position adjusting screw is provided. 82, 82, 82
The axial center position of the additional plug sleeve 7 is finely adjusted and fixed by the forward / backward adjustment.

The extension plug sleeve 7 inserted into and fixed to the extension plug insertion hole 6 has its axis centered upward from the top dead center surface 91 of the piston 9 in the combustion chamber 41 by an angle F of 16 degrees.
And the exhaust valve 43 side has an angle G of 5 degrees.
The piston is tilted, and the axis is arranged so as to cross the center E of the piston top dead center surface 91.
The distance H from the inner edge of the cam chain 52 located on the intake valve 42 side is 34.5 mm, and the distance J from the inner edge of the cam chain 52 located on the exhaust valve 43 side is about 2
The camshaft 5 is fixed at a distance K of 70 mm from the center of the camshaft 5.

The wall thickness of the rear end side of the additional plug sleeve 7 is set to 6.5 mm in order to ensure the highest possible strength, but the thickness is reduced to about 4 mm.
It is also possible to set the outer diameter dimension A to about 30 mm, and when the diameter is reduced in this way, it is possible to further change the arrangement dimensions of the respective parts within a range of several mm or several degrees. .

[0029]

The structure and method for adding a spark plug of an air-cooled single-cylinder engine for a motorcycle according to the present invention having the above-described structure are provided in a wall portion where a cam drive system accommodating chamber 13 on the right outside of the cylinder head 4 is formed. Are formed at predetermined positions on the outer surface of the cam drive system housing chamber 13 from the exposed outer wall surface toward the center E of the piston top dead center of the combustion chamber 41. , An additional plug insertion hole 6 penetrating between the cam chain 52 located below the camshaft sprocket 51 in the cam drive system housing chamber 13 and the combustion chamber 41 wall, A female screw portion 61 is formed on the inner peripheral wall surface of the additional plug insertion hole 6 corresponding to the wall of the combustion chamber 41, and a male screw portion 71 is formed on the distal end side of the additional plug insertion hole 6. ,
A sleeve 7 for an additional plug which has a tubular shape connecting the wall of the combustion chamber 41 and a predetermined position on the outer surface of the wall forming the cam drive system housing chamber 13 and is isolated from the cam drive system housing chamber 13.
Is inserted and screwed, and an oil leakage prevention collar 8 provided in the cam drive system accommodating chamber 13 is fitted and integrated with the engine main body 1 through the collar 8. 7, the spark plug 2 is inserted, screwed, and added.

The additional plug sleeve 7 forms a new attachment portion for detachably fixing the additional spark plug 2 at an appropriate position, and penetrates through the cam drive system accommodating chamber 13 in a state of being isolated. In addition, a protective wall for preventing engine oil from adhering to a terminal portion or a corrugation portion of the additional ignition plug 2 is formed.

The axis of the additional plug sleeve 7 is
1 above the top dead center surface 91 of the piston 9 in the combustion chamber 41
The arrangement is inclined at an angle F of 6 degrees, and the exhaust valve 43
Side and an angle G of 5 degrees, and 34.5 mm from the inner edge of the cam chain 52 located on the intake valve 42 side.
Of the cam chain 5 located on the exhaust valve 43 side with a distance H of
A distance J of 26.5 mm from the inner edge of 2 and a distance K of 70 mm from the center of the camshaft 5;
The additional plug sleeve 7 is inserted and fixed so as not to interfere with driving parts such as the camshaft sprocket 51 and the cam chain 52 and other components of the engine body 1 other than the cylinder head 4 such as the cylinder block 3. .

Further, the additional plug sleeve 7 has a male screw portion 71 on the front end side and a hexagonal head portion 73 for tightening on the rear end side, and is inserted into the insertion hole 6 for the additional plug. At this time, the tightening hexagonal head 73 is screwed and tightened to the female screw portion 61 of the additional plug insertion hole 6 by rotating the hexagonal head 73 using a wrench. While fitting the oil leakage prevention collar 8 having the annular gasket 81,
The periphery of the oil leakage prevention collar 8 is set in the cam drive system accommodation chamber 1.
3 is adhered and fixed to the inner wall surface with a heat-resistant adhesive for metal, connected to the cylinder head 4 and tightened with the position adjusting screws 82, 82, 82 to adjust the axial center position of the additional plug sleeve 7. Fine adjustment is made and the ignition electrode of the additional ignition plug 2 is fixed so as to be set toward the center of the combustion chamber 41.

The extension plug sleeve 7 has a male screw portion 71 at the distal end screwed and fixed to the female screw portion 61 of the extension plug mounting hole 6 to form a closed structure.
The engine oil inside 3 is prevented from flowing into the combustion chamber 41, and the oil leakage preventing collar 8 is provided via a rubber gasket 81 that is hermetically mounted on the additional plug sleeve 7. The engine oil in the cam drive system housing chamber 13 leaks from between the peripheral wall surface of the additional plug sleeve 7 and the outer wall surface of the cylinder head 4 by isolating the cam drive system housing chamber 13 from the outside of the cylinder head 4. A closed structure is formed so as not to cover.

[0034]

[Effect] As described above, the conventional ignition plug, intake / exhaust valve, camshaft sprocket, cam chain wound around the sprocket, and the like are arranged around the combustion chamber. Since a camshaft and a rocker arm are arranged in the upper part of the chamber, there is no space where a new spark plug can be added to a commercially available OHC single cylinder gasoline engine for motorcycles.
Although it was impossible to increase the output by using two plugs and many people gave up trying to increase the output by using two plugs, the air-cooled single-cylinder engine for motorcycles according to the present invention was developed. According to the additional spark plug structure and method, the additional spark plug is provided in the right side wall of the engine and penetrates the cam drive system accommodating chamber in which engine oil circulates to protect the additional spark plug from splashing of oil. In addition, an excellent feature that two plugs can be realized by being replaceable at an accurate position so that engine output can be improved can be obtained.

Further, a female screw portion is formed at a portion corresponding to the combustion chamber wall portion of the additional plug mounting hole, and a male screw portion is formed at the tip end side of the additional plug sleeve.
The coupling prevents the engine oil flowing around the cam drive system housing chamber from flowing into the combustion chamber, and the combustion gas burned and expanded in the combustion chamber flows out into the cam drive system housing chamber. In addition, if the structure is provided with an oil leakage prevention collar that fits into the additional plug sleeve in the cam drive system accommodating chamber, it is possible to prevent the ignition plug from being added. Advantageously, it is possible to prevent the engine oil from leaking to the outside, and it is possible to ensure the confidentiality that is concerned when an ignition plug is added.

Furthermore, the extension plug sleeve inserted and fixed to the cylinder head is restricted in the layout by the mechanical structure around the combustion chamber, but without compromising the easy extension position, the extension spark plug can be used. This is an excellent position opposite the existing ignition plug with the center of the combustion chamber in between, and the tip of the additional ignition plug is arranged to cross the center of the piston top dead center plane. Sparks from the plug for use will be concentrated and ignited in the center of the top dead center of the piston in a substantially symmetrical manner, and before the plug is added, the area that covers the corner of the combustion chamber where sufficient combustion was not obtained As a result of achieving reliable combustion up to a powerful explosive power, a significant increase in output has been achieved, resulting in an extremely effective feature that leads to a reduction in fuel consumption. There.

In particular, in the spark plug extension structure and the extension method described in the embodiment, the extension plug sleeve 7 has an angle F of 16 degrees with the axis of the extension plug sleeve 7 directed upward from the piston top dead center in the combustion chamber 41. To prevent the cylinder block 4 from protruding. The intake valve 42 is arranged at an angle G of 5 degrees toward the exhaust valve 43 side.
In addition to avoiding interference with the cam chain 52 located on the side of the intake valve 42, a distance H of 34.5 mm from the inner edge of the cam chain 52 located on the side of the intake valve 42, the exhaust valve 4
26.5 from the inner edge of the cam chain 52 located on the third side.
mm and a camshaft 5
Of the camshaft sprocket 51 and the cam chain 5
2 can be reliably prevented, and the additional spark plug 2 can be connected to the intake and exhaust valves 42,
It is arranged at the most ideal position without causing any interference with 43, and in combination with the original ignition plug, a strong ignition and explosion are caused, and extremely good combustion is obtained. have.

Further, in this embodiment, the additional plug sleeve 7 has a structure in which a hexagonal head portion 73 for tightening is provided on the rear end side, and the male screw portion provided on the front end side is provided. The three screws 71 for adjusting the position of the oil leakage preventing collar 8 are provided so that the screw 71 can be easily screwed, fixed or unscrewed and detached easily from the female screw portion 61 of the additional plug insertion hole 6. Each of 82, 82, 82 is advanced and retracted so that the axial center position of the additional plug sleeve 7 can be finely adjusted. The engine used for many years and other modified parts are provided. For some reason,
When the position of the ignition electrode of the plug needs to be slightly adjusted, it can be easily handled, so that the adjustment according to the engine condition is extremely easy to make. It has become.

As described above, the ignition plug extension structure and the extension method of the air-cooled single-cylinder engine for a motorcycle according to the present invention can achieve the intended purpose widely by its novel structure, and are extremely efficient. In addition to improving engine output and improving fuel efficiency, reducing incomplete combustion gas emissions and making it desirable in terms of pollution control. It is very suitable for not only engines for commercial vehicles but also engines used in motorcycle races where high output is important, as it is easy to add and the engine weight hardly increases. It has the advantage that it can be used regardless of whether it is a new car or a favorite car, and it is accepted and widely used by many users who want to improve output. It is expected to, it can be said to be the ones that contribute greatly to the activation of the future of the motorcycle industry.

[Brief description of the drawings]

The drawings show a typical embodiment embodying the technical idea of the spark plug extension structure and the extension method of the air-cooled single-cylinder engine for a motorcycle according to the present invention, and a conventional example.

FIG. 1 is a perspective view of a main part showing an exploded state of an additional structure of an ignition plug.

FIG. 2 is a longitudinal sectional view of a main part showing an additional structure of an ignition plug.

FIG. 3 is a bottom view of a cylinder head showing an additional structure of an ignition plug.

FIG. 4 is a side view of a main part showing an arrangement of an additional structure of an ignition plug.

FIG. 5 is a side view showing the structure of an additional plug sleeve with a partial cross section.

FIG. 6 is a front view showing an oil leakage prevention collar.

FIG. 7 is a longitudinal sectional view showing an oil leakage prevention collar.

FIG. 8 is a side view showing a motorcycle equipped with a conventional air-cooled single-cylinder engine.

FIG. 9 is an exploded perspective view showing a main part of a conventional air-cooled single-cylinder engine.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Engine main body 11 Same carburetor 12 Same exhaust pipe 13 Same cam drive system accommodation room 14 Same air cooling fin 2 Ignition plug 3 Cylinder block 4 Cylinder head 41 Same combustion chamber 42 Same intake valve 43 Same exhaust valve 5 Camshaft 51 Same camshaft Sprocket 52 Same Cam chain 6 Insertion hole for additional plug 61 Same female screw part 7 Additional plug sleeve 71 Same male screw part 72 Same female screw part 73 Same hexagonal head for tightening A Same rear end outer diameter B Same inner diameter C Same body thickness D Same tip side seat surface thickness F Same Upward inclination angle G Same Exhaust valve side inclination angle H Same Distance from intake valve side cam chain J Same Distance from exhaust valve side cam chain K Distance from camshaft center 8 Oil leakage prevention collar 81 Ring gasket DOO 82 the position adjusting screw 9 the piston 91 the top dead center plane E the piston top dead center surface center,

Claims (7)

[Claims] An OHC air-cooled single cylinder in which a spark plug is mounted on a left side wall portion of a cylinder head and a cam drive system accommodating chamber in which a camshaft sprocket and a cam chain are built in a right side wall across a combustion chamber. On the outside of the right side of the cylinder head of the engine and engine body, cut off a part or all of the air cooling fins on the outer surface of the cam drive system housing chamber forming wall, and from the exposed outer surface on the piston in the combustion chamber from the predetermined position. Direction towards the center of the dead center plane,
An extension plug insertion hole is formed so as to penetrate the cam drive system accommodation chamber forming wall portion, between the cam chains under the cam sprocket in the cam drive system accommodation room, and the combustion chamber wall portion, and then the extension is performed. A substantially cylindrical additional plug sleeve that connects the combustion chamber and a predetermined position on the outer surface of the wall on which the cam drive system housing chamber is formed is inserted into the plug insertion hole so as to be isolated from the cam drive system housing chamber. An air-cooled single-cylinder engine for a motorcycle, characterized in that an additional ignition plug is detachably screwed and attached to the additional plug sleeve while being fixedly attached to and integrated with the engine body by an appropriate coupling structure. Additional spark plug structure. 2. An OHC air-cooled single cylinder in which a spark plug is mounted on a left side wall of a cylinder head, and a cam drive system accommodating chamber in which a camshaft sprocket and a cam chain are built in a right side wall across a combustion chamber. On the outside of the right side of the cylinder head of the engine and engine body, cut off a part or all of the air cooling fins on the outer surface of the cam drive system housing chamber forming wall, and from the exposed outer surface on the piston in the combustion chamber from the predetermined position. Direction towards the center of the dead center plane,
The cam drive system accommodating chamber forming wall portion, between the cam chains below the cam sprocket in the cam drive system accommodating chamber, and through the combustion chamber wall portion, and a female screw portion is engraved on the combustion chamber wall portion. After the insertion hole for the additional plug is formed, the insertion hole for the additional plug has a male screw portion on the tip end side, so that the cam and the combustion chamber are separated from the cam drive system housing chamber. A substantially cylindrical sleeve for an additional plug that connects to a predetermined position on the outer surface of the drive system housing chamber forming wall is inserted and screwed in, and an oil leakage prevention collar provided in the cam drive system housing chamber is fitted. A spark plug extension structure for an air-cooled single-cylinder engine for motorcycles, wherein an extension spark plug is detachably screwed into and attached to the extension plug sleeve while being integrated with the engine body. 3. The extension plug sleeve has its axis centered upward from the piston top dead center in the combustion chamber by 15 degrees 30 minutes to 1 minute.
3. The air-cooled single-cylinder engine for a motorcycle according to claim 1, wherein the air-cooled single-cylinder engine according to claim 1 or 2 is arranged so as to be inclined at an angle of 6 degrees 30 minutes and to be arranged so as to intersect with the center of the piston top dead center in the combustion chamber. Additional spark plug structure. 4. The additional plug sleeve is arranged so that its axis is inclined to the exhaust side at an angle of 4 ° 30 minutes to 5 ° 30 minutes and crosses around the center of the piston top dead center in the combustion chamber. 4. The structure for adding an ignition plug to an air-cooled single-cylinder engine for a motorcycle according to any one of claims 1 to 3, wherein the ignition plug is provided. 5. The plug sleeve is located 33.5 to 35.5 mm away from the inner edge of the cam chain located on the intake side and 25.5 to 55.5 mm from the inner edge of the cam chain located on the exhaust side. 5. The additional spark plug structure for an air-cooled single-cylinder engine for a motorcycle according to claim 1, wherein the spark plug is arranged at a position separated by 27.5 mm. 6. The spark plug for an air-cooled single-cylinder engine for a motorcycle according to claim 1, wherein the plug sleeve is disposed 69.5 to 70.5 mm below the center of the camshaft. Extension structure. 7. An OHC air-cooled single cylinder in which a spark plug is mounted on a left side wall portion of a cylinder head and a cam drive system accommodating chamber in which a camshaft sprocket and a cam chain are built in a right side wall across a combustion chamber. On the outside of the right side of the cylinder head of the engine and engine body, cut off a part or all of the air cooling fins on the outer surface of the cam drive system housing chamber forming wall, and from the exposed outer surface on the piston in the combustion chamber from the predetermined position. Direction towards the center of the dead center plane,
The cam drive system accommodating chamber forming wall portion, between the cam chains below the cam sprocket in the cam drive system accommodating chamber, and through the combustion chamber wall portion, and a female screw portion is engraved on the combustion chamber wall portion. After the insertion hole for the additional plug is formed, the insertion hole for the additional plug has a male screw portion on the tip end side, so that the cam and the combustion chamber are separated from the cam drive system housing chamber. A substantially cylindrical sleeve for an additional plug that connects to a predetermined position on the outer surface of the drive system housing chamber forming wall is inserted and screwed in, and an oil leakage prevention collar provided in the cam drive system housing chamber is fitted. A spark plug for an air-cooled single-cylinder engine for a motorcycle, wherein the spark plug for an additional engine is detachably screwed and attached to the sleeve for the additional plug while being integrated with the engine body.