KR100569164B1 - Air-cooled internal combustion engine - Google Patents

Abstract

The present invention aims to improve the air cooling effect in the cooling wind passage, and to provide the spark plug at a position where attachment and detachment are easy, and to enable the effective air cooling.

In an air-cooled internal combustion engine provided with a dynamic valve mechanism in an upper portion of a combustion chamber, and a front and rear cooling wind passage along an exhaust port and an intake port between the combustion chamber and the copper valve mechanism, the exhaust port and A horizontal cooling wind passage communicating with the front and rear cooling wind passage is provided between the intake port, a spark plug is provided in the horizontal cooling wind passage, and the horizontal cooling is performed in the front and rear cooling wind passage. Cooling fins that curve toward the wind passage were provided. In addition, the exhaust port centerline was inclined with respect to the internal combustion engine front and rear directions so as to enlarge the front opening of the front and rear cooling wind passages.

Description

Air-cooled internal combustion engine {AIR-COOLED INTERNAL COMBUSTION ENGINE}

BRIEF DESCRIPTION OF THE DRAWINGS It is a longitudinal cross-sectional view of the principal part of the air-cooled internal combustion engine which concerns on one Embodiment of this invention.

2 is a view of the cross section of the main part of the internal combustion engine seen from the rear.

3 is a horizontal cross-sectional view (section III-III of FIG. 2) of the cylinder head of the internal combustion engine.

4 is a perspective view of the cooling fin as seen from an inclined rear side;

<Explanation of symbols for the main parts of the drawings>

1: air-cooled internal combustion engine 2: cylinder block

3: cylinder head 4: cylinder head cover

5: piston 6: combustion chamber

7: Exhaust port 7a: Exhaust port peripheral wall

8: exhaust valve 9: intake port

9a: Intake port peripheral wall 10: Intake valve

11 valve spring 12 valve spring

13: copper valve chamber 14: camshaft

15: exhaust cam 16: intake cam

17: rocker arm for exhaust 18: rocker arm shaft for exhaust

19: tappet 20: roller shaft

21: exhaust roller 22: intake rocker arm

23: intake rocker arm axis 24: tappet

25 roller axis 26 intake roller

27: spark plug 27a: electrode

28: chain chamber 28a: chain chamber main wall

29: driven sprocket 30: cam chain

31: spark plug mounting portion 32: front and rear cooling wind passage

33: front opening 34: rear opening

35: horizontal cooling wind passage 36: side opening

37: front pin 38: middle pin

38a: thick vertical section of middle pin 39: rear pin

39a: thick vertical section of rear fin 40: outer shell of combustion chamber head

The present invention relates to a cooling wind passage of an air-cooled internal combustion engine mounted on a motorcycle or the like.

The conventional air-cooled internal combustion engine has the following structures. The internal combustion engine is provided with two exhaust ports and two exhaust valves corresponding to them in the front part of the cylinder head, two intake ports and two intake valves corresponding to them in the rear part, respectively. The spark plug is provided in the position enclosed in the cylinder, and the camshaft is provided between the cylinder head and the cylinder head cover toward the left-right direction, and it passes between two exhaust valves, and between two intake valves, and a cylinder A cooling wind passage penetrating the head in the front-rear direction is provided, and a horizontal cooling wind passage communicating with the front-rear cooling wind passage is provided (see Patent Document 1, for example). In this example, a spark plug attachment hole is provided in the cylinder head surrounding the main body of the spark plug with a gap around it, and the spark plug attachment hole also communicates with the front-rear cooling wind passage.

When the motorcycle runs while the internal combustion engine is mounted on the motorcycle, air flows in from the front opening of the front-rear cooling wind passage, and a part thereof exits the upper outer portion of the internal combustion engine from the spark plug attachment hole, In addition, the other part exits the side outward of the internal combustion engine in the lateral cooling wind passage, and the remaining air escapes rearward from the rear opening of the front-rear cooling wind passage. In the course of this air flow, the cylinder head and the spark plug are cooled.

[Patent Document 1]

Japanese Patent Laid-Open No. 62-43050 (Figs. 2 and 3).

In the prior art, the air cooling effect is not sufficient in the cooling wind passage. In addition, the detachment of the spark plug is not easy. The present invention is intended to improve the air cooling effect in the cooling wind passage, and to provide the spark plug at a position where attachment and detachment are easily possible, and to enable the effective air cooling.

This invention solved the said subject, The invention of Claim 1 provided the copper valve mechanism in the upper part of a combustion chamber, and between the said combustion chamber and the said copper valve mechanism, an exhaust port and an intake port are provided. In the air-cooled internal combustion engine provided with the front and rear cooling air passages, a horizontal cooling wind passage communicating with the front and rear cooling wind passages is provided between the exhaust port and the intake port. A spark plug is provided and a cooling fin that curves toward the transverse cooling wind passage from the front-rear cooling wind passage is provided.

Since this invention is comprised in this way and a cooling fin is provided in the cooling wind passage above a combustion chamber, the surroundings of a combustion chamber can be cooled effectively. Since the spark plug is provided in the horizontal cooling wind passage, and the cooling fin is curved to guide the cooling wind in the direction of the spark plug, overheating of the spark plug can be prevented.

The invention according to claim 2 is characterized in that, in the air-cooled internal combustion engine according to claim 1, the exhaust port centerline is inclined with respect to the front and rear directions of the internal combustion engine so as to enlarge the front opening of the front and rear cooling wind passage. .

Since this invention is comprised in this way, since the opening area of a front opening becomes large and a large amount of air can be introduce | transduced into a cooling wind passage, the air cooling effect by running wind can be heightened.

1 is a longitudinal cross-sectional view of an essential part of an air-cooled internal combustion engine 1 according to an embodiment of the present invention, and shows an upper portion of an overhead camshaft type short cylinder internal combustion engine. In the drawing, the arrow F is pointing forward. In the drawing, the outer shell of the main part of the internal combustion engine 1 is composed of a cylinder block 2, a cylinder head 3, and a cylinder head cover 4. The piston 5 moves up and down inside the cylinder block 2. The combustion chamber 6 is formed in the lower surface side of the cylinder head 3. The cylinder head 3 is provided with an exhaust port 7 and an intake port 9 which lead to the combustion chamber 6. At an inner end of the exhaust port 7, an exhaust valve 8 is provided to open and close this passage. An exhaust pipe (not shown) is continuous at the outer end of the exhaust port 7. Moreover, the intake valve 10 which opens and closes this channel | path is provided in the inner end of the intake port 9. As shown in FIG. Carburetor which is not shown in figure continues in the outer end of the intake port 9. As shown in FIG.

The exhaust valve 8 is provided so that the shaft portion 8a is inclined forward in front of the cylinder head 3, and the valve spring 11 for pressurizing the exhaust valve 8 in the closing direction to the upper protrusion of the shaft portion 8a. Is equipped. The intake valve 10 is provided to the rear of the cylinder head 3 so that the shaft portion 10a is inclined backward, and the valve spring 12 for pressurizing the intake valve 10 in the direction of closing the intake valve 10 to the upper protrusion of the shaft portion 10a. Is equipped.

A dynamic valve chamber 13 is formed by the cylinder head 3 and the cylinder head cover 4, and a copper valve mechanism for opening and closing the exhaust valve 8 and the intake valve 10 is housed therein. have. In the V-shaped space formed by the exhaust valve 8 and the intake valve 10, the cam shaft 14 in the left and right directions orthogonal to the front-back direction of the internal combustion engine 1 is provided with the cylinder head 3 and the cylinder head cover ( The engagement with 4) is rotatably supported between the faces. The camshaft 14 is provided with an exhaust cam 15 for opening and closing the exhaust valve 8 and an intake cam 16 for opening and closing the intake valve 10.

The exhaust rocker arm 17 is rotatably supported by the exhaust rocker arm shaft 18 above the exhaust valve 8, and one end thereof is supported by the tappet 19 on the upper end of the shaft portion 8a of the exhaust valve. The other end is in contact with the exhaust cam 15 through the exhaust roller 21 supported by the roller shaft 20. The intake rocker arm 22 is swingably supported on the intake rocker arm shaft 23 above the intake valve 10, and one end thereof is provided on the upper end of the shaft portion 10a of the intake valve via the tappet 24. The other end is in contact with the intake cam 16 via the intake roller 26 supported by the roller shaft 25.

2 is a view of the cross section of the main part of the internal combustion engine 1 seen from the rear. In the figure, the spark plug 27 is attached to the cylinder head 3 at the right side thereof, and the electrode 27a at the tip thereof protrudes into the combustion chamber 6. Moreover, one end of the camshaft 14 protrudes in the chain chamber 28, and the driven sprocket 29 is being fixed to the protruding end. A drive sprocket (not shown) is fixed to the crankshaft, and the cam chain 30 is rotated in the chain chamber 28 between the drive sprocket and the driven sprocket 29. When the crankshaft rotates, the camshaft 14 is driven to rotate through the cam chain 30.

3 is a cross-sectional view taken along line III-III of FIG. 2 and shows a horizontal cross section of the cylinder head of the internal combustion engine. In the figure, a state where the spark plug 27 is removed and the spark plug attachment portion 31 is exposed is shown. Arrow F is pointing forward. Along the cylinder head center side of the circumferential wall 28a of the chain chamber 28, a front-rear cooling wind passage 32 is formed to penetrate the cylinder head in the front-rear direction. The space inserted between the chain chamber circumferential wall 28a and the exhaust port circumferential wall 7a is the front opening 33, and the space fitted between the chain chamber circumferential wall 28a and the intake port circumferential wall 9a is the rear opening 34. In addition, a horizontal cooling wind passage 35 is formed which communicates with the front and rear cooling wind passage 32, passes between the exhaust port circumferential wall 7a and the intake port circumferential wall 9a, and exits to the side of the internal combustion engine. have. The outer sides of both sides of the spark plug attachment portion 31 are the side openings 36. In addition, as shown in the figure, the centerline A of the exhaust port 7 is inclined by an angle α in the direction in which the front opening 33 is enlarged with respect to the front-rear direction line B of the internal combustion engine, The opening area of the opening 33 is enlarged to introduce a large amount of air into the cooling wind passage.

Three cooling fins are formed in the connecting portion between the front-rear cooling wind passage 32 and the transverse cooling wind passage 35 and the transverse cooling wind passage 35. Front pin 37, middle pin 38, rear pin 39. The hatching of the middle pin 38 and the rear pin 39 shown in the figure is a thick vertical part thickened for reinforcement, and the head part is connected to the ceiling of the cooling wind passage.

4 is a perspective view of the cooling fin as viewed from the inclined upper side. The hatching part of the crown part of the intermediate | middle fin 38 and the rear fin 39 is a cross section of the crown part of the thick vertical parts 38a and 39a connected to the ceiling of a cooling wind passage. In addition, in FIG. 1, the longitudinal cross sections of the three fins are drawn in the horizontal cooling wind passage 35. In FIG. 2, the three fins provided in the cooling wind passage are viewed from the rear of the internal combustion engine.

The configuration of the air-cooled internal combustion engine of the present embodiment is as described above. Running wind is generated when the motorcycle equipped with this internal combustion engine travels, and this running wind flows in from the front opening 33 of the front-rear cooling wind passage 32, and part of the driving wind is guided by a guide of three fins. By this, it passes through both sides of the spark plug 27 past the horizontal cooling wind passage 35 and flows out from the side opening 36. The other part exits between the three fins and flows out from the rear opening 34 of the front-rear cooling wind passage 32.

During traveling of the vehicle, the outer wall surfaces of the cylinder heads facing the front-rear cooling wind passage 32 and the transverse cooling wind passage 35 are cooled by the running wind. In particular, the high temperature of the combustion chamber 6 is transmitted to the front fins, the middle fins, and the rear fins 37, 38, and 39 via the combustion chamber crown outer shell 40 (FIG. 2), so that the front and rear cooling winds and the horizontal cooling are performed. Cooled by the wind. By these cooling actions, overheating of the cylinder head is prevented and seal deterioration around the cylinder head is prevented. Moreover, since the high temperature which generate | occur | produced in the electrode 27a of the spark plug 27 is transmitted to the outer exposure part of the spark plug 27, and is cooled by said horizontal cooling wind, deterioration by overheating of a spark plug is prevented. This prevents the life of the spark plug. Moreover, since the spark plug of this invention is provided inclined in the horizontal cooling wind path | pass, it is easy to detach | desorb at the side part of an internal combustion engine, and the maintainability is improved.

Furthermore, as shown in FIG. 3, since the center line A of the exhaust port 7 is inclined by the angle α in the direction in which the front opening 33 is enlarged with respect to the internal combustion engine front-rear direction line B, Since the opening area of the front opening 33 becomes large and a large amount of air can be introduced, the effect of air cooling by the running wind is large.

According to the present invention, the air cooling effect is improved in the cooling wind passage, and the spark plug is provided at a position where attachment and detachment are easy, and the effective air cooling is enabled.

Claims (2)

A dynamic valve mechanism is provided in the upper part of the combustion chamber, Front and rear between the combustion chamber and the copper valve mechanism from the front opening of the internal combustion engine between the exhaust port and the chain chamber circumferential wall to the rear opening between the intake port and the chain chamber circumferential wall. In the air-cooled internal combustion engine provided with a directional cooling wind passage, Between the exhaust port and the intake port, a horizontal cooling wind passage communicating with the front-rear cooling wind passage, through which cooling air introduced from the front of the internal combustion engine falls into the lateral opening of the internal combustion engine, is provided. A spark plug is provided in this horizontal cooling wind passage, An air-cooled internal combustion engine, characterized by providing a cooling fin that curves from the front-rear cooling wind passage toward the transverse cooling wind passage. The method of claim 1, The air-cooled internal combustion engine, characterized in that the exhaust port centerline is inclined with respect to the internal and rearward direction of the internal combustion engine so as to enlarge the front opening of the front-rear cooling wind passage.

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