CN222576783U - Engine with multiple ignition devices and motorcycle with same - Google Patents

Abstract

The utility model relates to an engine with multiple ignition devices and a motorcycle with the engine. The engine with multiple ignition devices includes a cylinder, a cylinder head assembly, a first spark plug and a cylinder head cover. The cylinder head assembly includes a cylinder head and an intake rocker arm, an exhaust rocker arm, an intake valve, an exhaust valve and a camshaft accommodated in the cylinder head. The cylinder head has a combination seat surface, a combustion chamber, an outer wall portion and a chain chamber. The outer wall portion has a first mounting hole that penetrates from the cylinder head to the combustion chamber. The first spark plug is installed in the first mounting hole, and the cylinder head cover is locked to the combination seat surface. The cylinder head further includes a second mounting hole extending from the cylinder head to the combustion chamber and a sleeve connected to the second mounting hole. The second mounting hole is located between the intake valve and the chain chamber or between the exhaust valve and the chain chamber. The cylinder head cover further includes a through hole. A first end of the sleeve is inserted into the through hole. A second end of the sleeve is assembled in the cylinder head. The engine further includes a second spark plug, which is assembled in the sleeve and installed in the second mounting hole.

Description

Engine with multiple ignition devices and motorcycle with same

Technical Field

The present utility model relates to an engine with multiple ignition devices and a motorcycle with the same, and more particularly, to an engine with multiple ignition devices and a motorcycle with the same, which are suitable for a power vehicle.

Background

In recent years, due to the strict requirements of environmental regulations and the energy crisis of various countries in the world, various motorcycle manufacturers actively develop low-pollution, low-fuel-consumption and high-performance engines, and taiwan belongs to the scooter motorcycle as the largest.

In the past, the cylinder heads of engines have been ignited using a spark plug, but the ever-increasing regulations in the future have not been met under various operating and load conditions, such that fuel consumption, pollution and performance have not been compromised. Therefore, in order to further reduce the fuel consumption and pollution of the scooter motorcycle, besides optimizing the combustion chamber, a second spark plug (for example, the taiwan new patent No. M607042) may be disposed on the engine, so that the combustion efficiency of the engine is improved under the combustion stroke. The configuration of the double spark plugs is particularly to solve the problems that when a motorcycle starts and accelerates, the engine mixture is thicker, and the combustion is required to be more efficient so as to avoid serious exhaust pollution, thereby reducing the noble metal usage amount of the catalytic converter for exhaust aftertreatment and reducing the oil consumption and pollution of the engine. However, the pursuit of pollution reduction and fuel consumption reduction must be continuous for environmental protection and energy conservation, so that there is still room for improvement in the prior art.

In addition, in the above-mentioned prior art, when the scooter type motorcycle with the front pedal is provided with the second spark plug, the first and second spark plugs are respectively arranged on opposite sides of the cylinder head air inlet when viewed from the upper side of the motorcycle due to the arrangement factor of engine cylinder head parts, and the second spark plug is positioned above the front section auxiliary pipe and below the rear section auxiliary pipe when viewed from the left side of the motorcycle, so that the motorcycle can be maintained only by disassembling more appearance parts, which is troublesome and has poor convenience. In the prior art, the engine is an air-cooled engine, and if the engine is a water-cooled engine, the second spark plug position easily causes poor water jacket flow passage to influence the cooling effect.

The inventors have paid attention to an engine with a plurality of ignition devices and a motorcycle with the engine, which solve the above problems, and have completed the present utility model through several research experiments.

Disclosure of utility model

The main object of the present utility model is to provide an engine with a plurality of ignition devices and a motorcycle with the engine, wherein the cylinder head further comprises a second mounting hole penetrating from the cylinder head to the combustion chamber and a sleeve communicated with the second mounting hole by adjusting the arrangement positions of the first spark plug and the second spark plug and optimizing the arrangement structure of the second spark plug, and the cylinder head cover further comprises a through hole, the first end of the sleeve penetrates through the through hole, and the second end of the sleeve is assembled on the cylinder head, so that the engine has better assembling and maintaining properties than the prior art, and is an optimal design.

In order to achieve the above object, the engine with a plurality of ignition devices of the present utility model comprises a cylinder, a cylinder head assembly, a first spark plug and a cylinder head cover. The cylinder head assembly is fixedly arranged on the cylinder and comprises a cylinder head, an air inlet rocker arm, an air outlet rocker arm, an air inlet valve, an air outlet valve and a cam shaft which are accommodated in the cylinder head, the cylinder head is provided with a combined seat surface, a combustion chamber, an outer wall part and a chain chamber, the outer wall part and the chain chamber are respectively positioned at two opposite end sides of the cam shaft, and the outer wall part is provided with a first mounting hole which penetrates through the cylinder head to the combustion chamber. The first spark plug is mounted in the first mounting hole, and the top end of the first spark plug is located outside the joint seat surface as viewed from the axial direction of the cylinder. The cylinder head cover is locked and attached to the combining seat surface. The cylinder head further comprises a second mounting hole penetrating through the combustion chamber from the cylinder head and a sleeve communicated with the second mounting hole, the second mounting hole is located between the air inlet valve and the chain chamber or between the exhaust valve and the chain chamber as seen from the axial direction of the cylinder, the second mounting hole is located on the inner side of the combined seat surface, the cylinder head cover further comprises a penetrating hole, a first end of the sleeve penetrates through the penetrating hole, a second end of the sleeve is assembled on the cylinder head, and the engine further comprises a second spark plug which is assembled in the sleeve and is installed in the second mounting hole.

In an embodiment, the bonding surface may be an annular structure.

In one embodiment, the first spark plug may not overlap the camshaft and the second spark plug may overlap the camshaft as viewed from a direction perpendicular to both the axis of the camshaft and the axis of the cylinder.

In one embodiment, the sleeve may overlap the engagement seat surface as viewed in the axial direction of the camshaft.

In one embodiment, the through hole may overlap the joint seat surface when viewed in the axial direction of the cylinder.

In one embodiment, a sealing member may be disposed between the cylinder head cover and the sleeve for sealing the through hole.

In an embodiment, the second end of the sleeve may be tightly fitted to the cylinder head or may be loosely fitted to the cylinder head.

In an embodiment, the axis of the intake valve and the axis of the second spark plug or the axis of the exhaust valve and the axis of the second spark plug are disposed on two sides of the first center line of the combustion chamber, respectively, when viewed from the combustion chamber toward the axis of the cylinder.

In an embodiment, the axis of the intake valve and the axis of the second spark plug or the axis of the exhaust valve and the axis of the second spark plug are disposed on two sides of the second center line of the combustion chamber, respectively, when viewed from the combustion chamber toward the axis of the cylinder.

In one embodiment, the engine may be a water cooled engine, and the cylinder head may further include a water jacket surrounding the first mounting hole and the second mounting hole for cooling the first spark plug and the second spark plug. Alternatively, the engine may be an air-cooled engine.

The motorcycle of the present utility model includes one frame, one oil tank, one article holding box and one engine with several ignition devices. The frame comprises a head pipe, a main pipe, a bottom pipe and a tail pipe which are connected in sequence. The oil tank is locked and attached to the frame, and the storage box is locked and attached to the frame. The engine group is arranged on the frame and comprises a cylinder, a cylinder head assembly, a first spark plug and a cylinder head cover, wherein the cylinder head assembly is fixedly arranged on the cylinder and comprises a cylinder head, an air inlet rocker arm, an air outlet rocker arm, an air inlet valve, an air outlet valve and a cam shaft, the cylinder head is provided with a combination seat surface, a combustion chamber, an outer wall part and a chain chamber, the outer wall part and the chain chamber are respectively positioned at two opposite end sides of the cam shaft, the outer wall part is provided with a first mounting hole penetrating through the combustion chamber from the cylinder head, the first spark plug is mounted in the first mounting hole, the top end of the first spark plug is positioned at the outer side of the combination seat surface when being observed from the axial direction of the cylinder, and the cylinder head cover is locked and attached to the combination seat surface. The cylinder head further comprises a second mounting hole penetrating through the combustion chamber from the cylinder head and a sleeve communicated with the second mounting hole, the second mounting hole is arranged between the air inlet valve and the chain chamber or between the exhaust valve and the chain chamber as seen from the axial direction of the cylinder, the second mounting hole is arranged on the inner side of the combining seat surface, the cylinder head cover further comprises a through hole, a first end of the sleeve penetrates through the through hole, a second end of the sleeve is assembled on the cylinder head, the engine further comprises a second spark plug, the second spark plug is assembled in the sleeve and is mounted in the second mounting hole, and the first spark plug and the second spark plug are both arranged behind the oil tank and below a bottom surface of the storage box and above an extension line of the bottom pipe as seen from the side view direction of the motorcycle.

In one embodiment, the sleeve and tailpipe may partially overlap when viewed from the side of the motorcycle.

In one embodiment, the bottom pipe may be an approximately straight line segment.

In one embodiment, the tail pipe may be a rising curved section.

In one embodiment, the engine is configured to swing relative to the frame.

In one embodiment, the motorcycle may be a scooter type motorcycle.

The foregoing summary and the following detailed description are exemplary in nature and are intended to further illustrate the utility model as claimed. Other objects and advantages of the present utility model will be apparent from the following detailed description and the accompanying drawings.

Drawings

Fig. 1 is a perspective view of an engine according to a first embodiment of the present utility model.

FIG. 2 is a top view of a cylinder head assembly and cylinder head cover according to a first embodiment of the present utility model.

FIG. 3 is a top view of a cylinder head assembly according to a first embodiment of the present utility model.

FIG. 4 is a perspective view, partially in section, of a cylinder head assembly according to a first embodiment of the present utility model.

FIG. 5 is a bottom view of the cylinder head assembly of the first embodiment of the present utility model.

FIG. 6 is a cross-sectional view of a cylinder head assembly according to a first embodiment of the present utility model.

FIG. 7 is a cross-sectional view of another perspective of a cylinder head assembly according to a first embodiment of the present utility model.

Fig. 8A and 8B are configuration structural diagrams of a water jacket of a first embodiment of the present utility model.

FIG. 9 is a top view of a cylinder head assembly and cylinder head cover according to a second embodiment of the present utility model.

FIG. 10 is a top view of a cylinder head assembly according to a second embodiment of the present utility model.

FIG. 11 is a perspective view, partially in section, of a cylinder head assembly according to a second embodiment of the present utility model.

FIG. 12 is a bottom view of a cylinder head assembly according to a second embodiment of the present utility model.

FIG. 13 is a cross-sectional view of a cylinder head assembly according to a second embodiment of the present utility model.

FIG. 14 is a cross-sectional view of another perspective of a cylinder head assembly according to a second embodiment of the present utility model.

Fig. 15A and 15B are configuration structural diagrams of a water jacket according to a second embodiment of the present utility model.

Fig. 16 is a side view of a motorcycle according to a third embodiment of the present utility model.

Fig. 17 is a partial front view of a motorcycle according to a third embodiment of the present utility model.

Fig. 18 is a side view of a motorcycle according to a fourth embodiment of the present utility model.

Fig. 19 is a partial front view of a motorcycle of a fourth embodiment of the present utility model.

Description of main reference numerals:

1,1' engine

10,10' Motorcycle

11. Frame of bicycle

111. Head pipe

112. Main pipe

113. Bottom pipe

114. Tail pipe

12. Oil tank

13. Storage box

130. Bottom surface

2. Cylinder with a cylinder head

3,3' Cylinder head assembly

30. Sleeve barrel

301. First end

302. Second end

31. Cylinder head

311. Combined seat surface

312. Combustion chamber

313. Outer wall portion

314. Chain chamber

32. Inlet rocker arm

33. Exhaust rocker arm

34. Air inlet valve

340. Axle center

35. Exhaust valve

350. Axle center

36. Cam shaft

37. Water jacket

4. First spark plug

5,5' Cylinder head cover

51. Sealing element

6. Second spark plug

60. Axle center

C1 A first center line

C2 A second center line

C3 Extension wire

H1 First mounting hole

H2 Second mounting hole

H3 Through hole

L1, L2 axis

Detailed Description

Fig. 1 to 4 are a perspective view of an engine, a top view of a cylinder head assembly and a cylinder head cover, a top view of a cylinder head assembly, and a partially cut-away perspective view of a cylinder head assembly, respectively, according to a first embodiment of the present utility model. In the figure, an engine 1 is shown with a plurality of ignition devices, in this embodiment two spark plugs, mainly comprising a cylinder 2, a cylinder head assembly 3, a first spark plug 4, a cylinder head cover 5 and a second spark plug 6.

The cylinder head assembly 3 is fixedly arranged on the cylinder 2, and comprises a cylinder head 31, an air inlet rocker arm 32, an air outlet rocker arm 33, an air inlet valve 34, an air outlet valve 35 and a cam shaft 36 which are accommodated in the cylinder head 31, wherein the cylinder head 31 is provided with a combined seat surface 311, a combustion chamber 312, an outer wall 313, a chain chamber 314, a first mounting hole h1, a second mounting hole h2 and a sleeve 30. The engaging seat 311 is formed in a ring-shaped structure along the top end edge of the cylinder head 31, and the cylinder head cover 5 is locked to the engaging seat 311. The combustion chamber 312 is located in the accommodating space below the cylinder head 31, the outer wall portion 313 and the chain chamber 314 are located at opposite end sides of the cam shaft 36, the outer wall portion 313 has a first mounting hole h1 penetrating from the cylinder head 31 to the combustion chamber 312, the cylinder head 31 further includes a second mounting hole h2 penetrating from the cylinder head 31 to the combustion chamber 312, the second mounting hole h2 communicates with the sleeve 30, in this embodiment, the second mounting hole h2 is located between the exhaust valve 35 and the chain chamber 314 as viewed from the direction of the axis L1 of the cylinder 2, and the second mounting hole h2 is located inside the joint seat surface 311.

The first spark plug 4 is attached to the first attachment hole h1, and the tip of the first spark plug 4 is located outside the joint seat surface 311 as viewed from the direction of the axis L1 of the cylinder 2. The second spark plug 6 is assembled in the sleeve 30 and is mounted in the second mounting hole h2. The cylinder head cover 5 further includes a through hole h3, and the through hole h3 overlaps the joint seat surface 311 when viewed from the direction of the axis L1 of the cylinder 2, a first end 301 of the sleeve 30 is disposed through the through hole h3, and a second end 302 of the sleeve 30 may be tightly fitted and fixed to the cylinder head or may be loosely fitted and fixed to the cylinder head, in this embodiment, tightly fitted and fixed to the cylinder head 31, so that the sleeve 30 and the second mounting hole h2 form a communicating through hole for passing through the second spark plug 6. In addition, a sealing member 51 is disposed between the cylinder head cover 5 and the sleeve 30 in this embodiment, such that the sealing member 51 is sleeved on the sleeve 30 to seal the through hole h3.

FIG. 5 is a bottom view of the cylinder head assembly of the first embodiment of the present utility model. As shown in the drawing, in the present embodiment, the axial center 340 of the intake valve 34 and the axial center 60 of the second plug 6 are provided on both sides of the first center line C1 of the combustion chamber 312, respectively, as viewed from the combustion chamber 312 toward the axis L1 of the cylinder 2. The axis 350 of the exhaust valve 35 and the axis 60 of the second spark plug 6 are disposed on both sides of the second center line C2 of the combustion chamber 312.

FIG. 6 is a cross-sectional view of a cylinder head assembly according to a first embodiment of the present utility model. As shown, the first spark plug 4 does not overlap the camshaft 36, and the second spark plug 6 overlaps the camshaft 36, as viewed from a direction perpendicular to both the axis L2 of the camshaft 36 and the axis L1 of the cylinder 2.

FIG. 7 is a cross-sectional view of another perspective of a cylinder head assembly according to a first embodiment of the present utility model. As shown in the drawing, the sleeve 30 overlaps the joint seat surface 311 as viewed in the direction of the axis L2 of the camshaft 36.

Fig. 8A and 8B are configuration structural diagrams of a water jacket of a first embodiment of the present utility model. As shown in the drawing, the engine 1 of the present embodiment is a water-cooled engine, the cylinder head 31 further includes a water jacket 37 surrounding the first mounting hole h1 and the second mounting hole h2, which is helpful for cooling the vicinity of the first mounting hole h1 and the second mounting hole h2, and further cooling the first spark plug 4 and the second spark plug 6, but the configuration structure of the plurality of ignition devices of the present embodiment is not limited to the water-cooled engine, and may be an air-cooled engine.

Fig. 9 to 11 are a top view of a cylinder head assembly and a cylinder head cover, a top view of the cylinder head assembly, and a partially cut-away perspective view of the cylinder head assembly, respectively, according to a second embodiment of the present utility model. The basic structure of the engine with a plurality of ignition devices is the same as that of the first embodiment, and referring to fig. 1, in this embodiment, the plurality of ignition devices are two spark plugs, and mainly include a cylinder 2, a cylinder head assembly 3', a first spark plug 4, a cylinder head cover 5', and a second spark plug 6, which are only adjusted in the structural arrangement of the cylinder head assembly 3 'and the cylinder head cover 5', so that the cylinder 2 can refer to the reference sign of fig. 1.

The cylinder head assembly 3' is fixedly arranged on the cylinder 2, and comprises a cylinder head 31, an air inlet rocker arm 32, an air outlet rocker arm 33, an air inlet valve 34, an air outlet valve 35 and a cam shaft 36 which are accommodated in the cylinder head 31, wherein the cylinder head 31 is provided with a combined seat surface 311, a combustion chamber 312, an outer wall 313, a chain chamber 314, a first mounting hole h1, a second mounting hole h2 and a sleeve 30. The engaging seat surface 311 is formed in a ring-shaped structure along the top end edge of the cylinder head 31, and the cylinder head cover 5' is locked to the engaging seat surface 311. The combustion chamber 312 is located in the accommodating space below the cylinder head 31, the outer wall portion 313 and the chain chamber 314 are located at opposite end sides of the cam shaft 36, the outer wall portion 313 has a first mounting hole h1 penetrating from the cylinder head 31 to the combustion chamber 312, the cylinder head 31 further includes a second mounting hole h2 penetrating from the cylinder head 31 to the combustion chamber 312, the second mounting hole h2 communicates with the sleeve 30, in this embodiment, the second mounting hole h2 is located between the intake valve 34 and the chain chamber 314 as viewed from the direction of the axis L1 of the cylinder 2, and the second mounting hole h2 is located inside the joint seat surface 311.

The first spark plug 4 is attached to the first attachment hole h1, and the tip of the first spark plug 4 is located outside the joint seat surface 311 as viewed from the direction of the axis L1 of the cylinder 2. The second spark plug 6 is assembled in the sleeve 30 and is mounted in the second mounting hole h2. The cylinder head cover 5' further includes a through hole h3, and the through hole h3 overlaps the joint seat surface 311 when viewed from the direction of the axis L1 of the cylinder 2, a first end 301 of the sleeve 30 is disposed through the through hole h3, a second end 302 of the sleeve 30 may be tightly fitted and fixed to the cylinder head, or may be loosely fitted and fixed to the cylinder head, in this embodiment, tightly fitted and fixed to the cylinder head 31, so that the sleeve 30 and the second mounting hole h2 form a communicating through hole for passing through the second spark plug 6. In addition, a sealing member 51 is disposed between the cylinder head cover 5' and the sleeve 30 in this embodiment, such that the sealing member 51 is sleeved on the sleeve 30 to seal the through hole h3.

FIG. 12 is a bottom view of a cylinder head assembly according to a second embodiment of the present utility model. As shown in the drawing, in the present embodiment, the axial center 350 of the exhaust valve 35 and the axial center 60 of the second plug 6 are provided on both sides of the first center line C1 of the combustion chamber 312, respectively, as viewed from the combustion chamber 312 toward the axis L1 of the cylinder 2. The axis 340 of the intake valve 34 and the axis 60 of the second spark plug 6 are disposed on both sides of the second center line C2 of the combustion chamber 312.

FIG. 13 is a cross-sectional view of a cylinder head assembly according to a second embodiment of the present utility model. As shown, the first spark plug 4 does not overlap the camshaft 36, and the second spark plug 6 overlaps the camshaft 36, as viewed from a direction perpendicular to both the axis L2 of the camshaft 36 and the axis L1 of the cylinder 2.

FIG. 14 is a cross-sectional view of another perspective of a cylinder head assembly according to a second embodiment of the present utility model. As shown in the drawing, the sleeve 30 overlaps the joint seat surface 311 as viewed in the direction of the axis L2 of the camshaft 36.

Fig. 15A and 15B are configuration structural diagrams of a water jacket according to a second embodiment of the present utility model. As shown in the drawing, the engine of the present embodiment is a water-cooled engine, and the cylinder head 31 further includes a water jacket 37 surrounding the first mounting hole h1 and the second mounting hole h2, which is helpful for cooling the vicinity of the first mounting hole h1 and the second mounting hole h2, so as to achieve the cooling effect on the first spark plug 4 and the second spark plug 6.

Fig. 16 and 17 are a side view of a motorcycle and a partial front view of the motorcycle, respectively, according to a third embodiment of the present utility model. The motorcycle 10 of the present embodiment is a scooter type motorcycle, and includes a frame 11, an oil tank 12, a storage box 13, and an engine 1. The frame 11 includes a head pipe 111, a main pipe 112, a bottom pipe 113 and a tail pipe 114 connected in sequence, wherein the bottom pipe 113 is an approximately straight section, and the tail pipe 114 is an ascending curved section. The oil tank 12 and the storage box 13 are respectively locked and attached to the frame 11. The engine 1 in this embodiment is assembled on the frame 11 and can swing and rotate relative to the frame 11, which is the engine 1 in the first embodiment, so the description of the structural features of the engine 1 can be referred to in the first embodiment, and will not be repeated here.

The first and second spark plugs 4 and 6 are disposed behind the fuel tank 12, the first and second spark plugs 4 and 6 are disposed below a bottom 130 of the storage box 13, and the first and second spark plugs 4 and 6 are disposed above an extension line C3 of the bottom pipe 113, as viewed from a side view of the motorcycle 10. Further, the sleeve 30 partially overlaps the tail pipe 114 as viewed from the side view of the motorcycle 10.

Fig. 18 and 19 are a side view of a motorcycle and a partial front view of the motorcycle, respectively, according to a fourth embodiment of the present utility model. The motorcycle 10 'of the present embodiment is a scooter type motorcycle, and includes a frame 11, an oil tank 12, a storage box 13, and an engine 1'. The frame 11 includes a head pipe 111, a main pipe 112, a bottom pipe 113 and a tail pipe 114 connected in sequence, wherein the bottom pipe 113 is an approximately straight section, and the tail pipe 114 is an ascending curved section. The oil tank 12 and the storage box 13 are respectively locked and attached to the frame 11. The engine 1 'of the present embodiment is assembled on the frame 11 and can swing and rotate relative to the frame 11, which is the engine of the second embodiment, so the description of the structural features of the engine 1' can be referred to the second embodiment, and will not be repeated here.

The first and second spark plugs 4 and 6 are disposed behind the fuel tank 12, the first and second spark plugs 4 and 6 are disposed below a bottom 130 of the storage box 13, and the first and second spark plugs 4 and 6 are disposed above an extension line C3 of the bottom pipe 113, as viewed from a side view of the motorcycle 10'. Further, the sleeve 30 partially overlaps the tail pipe 114 as viewed from the side view of the motorcycle 10'.

The foregoing embodiments are merely illustrative, and the scope of the utility model is defined by the claims rather than by the foregoing embodiments.

Claims (17)

1. An engine having a plurality of ignition devices, comprising:

A cylinder;

the cylinder head assembly is fixedly arranged on the cylinder and comprises a cylinder head, an air inlet rocker arm, an air outlet rocker arm, an air inlet valve, an air outlet valve and a cam shaft which are contained in the cylinder head, the cylinder head is provided with a combined seat surface, a combustion chamber, an outer wall part and a chain chamber, the outer wall part and the chain chamber are respectively positioned at two opposite end sides of the cam shaft, and the outer wall part is provided with a first mounting hole which penetrates through the cylinder head to the combustion chamber;

A first spark plug mounted in the first mounting hole, the top end of the first spark plug being located outside the joint seat surface as viewed from the axial direction of the cylinder, and

A cylinder head cover, which is locked and attached to the combined seat surface;

The cylinder head is characterized by further comprising a second mounting hole penetrating through the combustion chamber from the cylinder head and a sleeve communicated with the second mounting hole, the second mounting hole is positioned between the air inlet valve and the chain chamber or between the air outlet valve and the chain chamber as seen from the axis direction of the cylinder, the second mounting hole is positioned at the inner side of the combined seat surface, the cylinder head cover further comprises a through hole, a first end of the sleeve penetrates through the through hole, a second end of the sleeve is assembled on the cylinder head, and the engine further comprises a second spark plug which is assembled in the sleeve and is mounted in the second mounting hole.

2. The engine of claim 1 having a plurality of ignition devices, wherein the engagement seat is of a ring-shaped configuration.

3. The engine of claim 1 having a plurality of ignition devices, wherein the first spark plug does not overlap the camshaft and the second spark plug overlaps the camshaft as viewed in a direction perpendicular to both the axis of the camshaft and the axis of the cylinder.

4. The engine with a plurality of ignition devices as recited in claim 1, wherein said sleeve overlaps said joint seat surface as viewed in an axial direction of said camshaft.

5. The engine with multiple ignition devices as recited in claim 1, wherein said through hole overlaps said joint seat surface as viewed in an axial direction of said cylinder.

6. An engine having a plurality of ignition devices as recited in claim 1, wherein a seal is provided between said cylinder head cover and said sleeve for sealing said through hole.

7. The engine of claim 1, wherein the second end of the sleeve is secured to the cylinder head in a close-fitting manner.

8. The engine with a plurality of ignition devices according to claim 1, wherein the axis of the intake valve and the axis of the second spark plug, or the axis of the exhaust valve and the axis of the second spark plug are respectively disposed on both sides of the first center line of the combustion chamber as viewed from the combustion chamber toward the axis direction of the cylinder.

9. The engine with a plurality of ignition devices according to claim 1, wherein the axis of the intake valve and the axis of the second spark plug, or the axis of the exhaust valve and the axis of the second spark plug, are respectively disposed on both sides of the second center line of the combustion chamber as viewed from the combustion chamber toward the axis direction of the cylinder.

10. The engine of claim 1, wherein the engine is a water cooled engine, and the cylinder head further comprises a water jacket surrounding the first mounting hole and the second mounting hole.

11. The engine with multiple ignition devices of claim 1, wherein the engine is an air-cooled engine.

12. A motorcycle, comprising:

A frame comprising a head pipe, a main pipe, a bottom pipe and a tail pipe which are connected in sequence;

The oil tank is locked and attached to the frame;

A storage box locked and attached to the frame, and

The engine is assembled on the frame and comprises a cylinder, a cylinder head assembly, a first spark plug and a cylinder head cover, wherein the cylinder head assembly is fixedly arranged on the cylinder and comprises a cylinder head, an air inlet rocker arm, an air outlet rocker arm, an air inlet valve, an air outlet valve and a cam shaft which are arranged in the cylinder head, the cylinder head is provided with a combined seat surface, a combustion chamber, an outer wall part and a chain chamber, the outer wall part and the chain chamber are respectively positioned at two opposite end sides of the cam shaft, the outer wall part is provided with a first mounting hole penetrating from the cylinder head to the combustion chamber, the first spark plug is mounted on the first mounting hole, the top end of the first spark plug is positioned at the outer side of the combined seat surface when viewed from the axis direction of the cylinder, and the cylinder head cover is locked on the combined seat surface;

The cylinder head is characterized by further comprising a second mounting hole penetrating through the combustion chamber from the cylinder head and a sleeve communicated with the second mounting hole, wherein the second mounting hole is positioned between the air inlet valve and the chain chamber or between the air outlet valve and the chain chamber as seen from the axial direction of the cylinder, the second mounting hole is positioned at the inner side of the combining seat surface, the cylinder head cover further comprises a through hole, a first end of the sleeve penetrates through the through hole, a second end of the sleeve is assembled on the cylinder head, the engine further comprises a second spark plug, the second spark plug is assembled in the sleeve and is mounted in the second mounting hole, and the first spark plug and the second spark plug are both arranged at the rear of the oil tank, below a bottom surface of the storage box and above an extension line of the bottom pipe as seen from the side view direction of the motorcycle.

13. A motorcycle as claimed in claim 12 wherein the sleeve overlaps the tailpipe portion when viewed from a side view of the motorcycle.

14. A motorcycle as claimed in claim 12 wherein the base pipe is an approximately straight section.

15. A motorcycle as claimed in claim 12 wherein the tail pipe is a rising curved section.

16. A motorcycle as claimed in claim 12 wherein the engine is rocking with respect to the frame.

17. A motorcycle as claimed in claim 12 wherein the motorcycle is a scooter type motorcycle.