Gasoline engine for motorcycle

Abstract

The invention belongs to the technical field of motorcycles, and particularly relates to a gasoline engine for motorcycles, which comprises a crankshaft box body and a cylinder head, a pump body is arranged on the side edge of the cylinder head, and a main water inlet channel, a mounting cavity, a minor-cycle water inlet channel, a major-cycle water outlet channel, a major-cycle water inlet channel and a pump water outlet channel are arranged in the pump body. The thermostat divides the installation cavity into a first cavity and a second cavity, the main water inlet channel is communicated with the cylinder head water outlet channel and the first cavity, the small circulation water inlet channel is communicated with the first cavity and the pump cavity, the large circulation water outlet channel is communicated with the second cavity and the water tank water inlet channel, and the large circulation water inlet channel is communicated with the water tank water outlet channel and the pump cavity. The pump water outlet channel is communicated with the pump cavity and the cylinder head water inlet channel, and when the temperature does not reach a set value, the thermostat disconnects the first cavity and the second cavity; and when the temperature reaches a set value, the thermostat is communicated with the first chamber and the second chamber. Additional water pipe connection is not needed, the structure is compact, the occupied space is small, meanwhile, the number of parts is small, installation is easy and convenient, and cost is low.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of motorcycle technology, in particular to a gasoline engine for motorcycle. BACKGROUND

[0002] The water-cooled engine of motorcycle relies on water to cool the engine, and the cooling system is composed of a water pump, a radiator and water pipes connecting them, and the working cycle of the cooling water has two working states, one is high-temperature state: the cooling water circulates, and the other is low-temperature state: the cooling water circulates. The high-temperature state cooling water passes through the radiator and the water pump, and the low-temperature state cooling water passes through the water pump but not through the radiator. The high-temperature state and the low-temperature state are automatically completed by installing a thermostat on the pipeline.

[0003] Chinese patent (publication number CN107489509A, application date 2017.10.19, publication date 2017.12.19) discloses a motorcycle engine water cooling device, which comprises a cylinder head, a cylinder body (i.e. a cylinder head), a water channel, a water pump, an oil pump gear, a thermostat, a first water channel is arranged on the cylinder head, a second water channel is arranged on the cylinder body, the second water channel is connected with the water outlet of the water pump, the first water channel and the second water channel are communicated, the water pump is driven by the oil pump gear, a micro generator is arranged on the cylinder body, the micro generator is driven by the oil pump gear, a refrigeration structure is arranged on the cylinder body, the refrigeration structure is electrically connected with the micro generator, and the refrigeration structure is communicated with the second water channel. The lower part of the cylinder body is provided with a water inlet, the water inlet is communicated with the second water channel, and the upper part of the cylinder head is provided with a water outlet, the water outlet is communicated with the first water channel. The water outlet is connected with the thermostat through a conduit, and the thermostat is provided with a sensing device for detecting water temperature. The thermostat is provided with a high-temperature pipe and a low-temperature pipe, the high-temperature pipe is connected with a radiator, the radiator is connected with the water pump, and the low-temperature pipe is directly connected with the water pump. The cooling water flows out from the water outlet on the cylinder head, flows to the thermostat through the conduit, the sensing device in the thermostat automatically detects the water temperature, when the water temperature exceeds the specified value, the high-temperature valve opens, the water flows to the radiator through the high-temperature pipe, is cooled after heat dissipation through the radiator, and then flows back to the water pump by gravity; when the water temperature does not exceed the specified value, the low-temperature valve opens, the water flows back to the water pump through the low-temperature pipe, and the cycle is repeated.

[0004] The motorcycle engine water cooling device has the following disadvantages: the thermostat, the water pump and the radiator are separately arranged, and are respectively connected with the thermostat, the water pump and the cylinder head through additional water pipes, the structure is not compact, the space occupied is large, and the installation is troublesome. SUMMARY

[0005] The motorcycle gasoline engine has the advantages of compact structure, small space occupation, less parts, simple installation, low cost and no need of additional water pipe connection.

[0006] The motorcycle gasoline engine has the advantages of compact structure, small space occupation, less parts, simple installation, low cost and no need of additional water pipe connection.

[0007] The motorcycle gasoline engine has the advantages of compact structure, small space occupation, less parts, simple installation, low cost and no need of additional water pipe connection.

[0008] The motorcycle gasoline engine has the advantages of compact structure, small space occupation, less parts, simple installation, low cost and no need of additional water pipe connection.

[0009] The motorcycle gasoline engine has the advantages of compact structure, small space occupation, less parts, simple installation, low cost and no need of additional water pipe connection.

[0010] In the above-mentioned gasoline engine for motorcycle, the thermostat comprises a bracket I, a bracket II mounted on one end of the bracket I, and a valve core assembly sliding between the bracket I and the bracket II, the end of the bracket I connecting the bracket II is provided with an annular portion, the edge of the annular portion is turned outward to form a mounting protrusion clamped between the pump shell I and the pump shell II, and the middle of the annular portion is formed with a valve port, the valve core assembly comprises a mounting sleeve, a temperature sensing element arranged in the mounting sleeve, a push rod sliding in the mounting sleeve, a valve plate connected to the end of the mounting sleeve, and a spring arranged between the bracket II and the valve plate, the end of the push rod close to the bracket I protrudes out of the mounting sleeve to abut against the bracket I, and the other end abuts against the temperature sensing element, when the temperature rises, the temperature sensing element expands, the push rod protrudes out of the mounting sleeve, the mounting sleeve and the valve plate move to the end away from the bracket I, the spring is compressed, the valve plate opens the valve port, and the chamber I and the chamber II are communicated; when the temperature drops, under the elastic force of the spring, the mounting sleeve and the valve plate move to the side of the bracket I until the valve plate blocks the valve port, and the chamber I and the chamber II are disconnected.

[0011] In the above-mentioned gasoline engine for motorcycle, the crankcase is provided with a crankshaft, the crankcase comprises a left crankcase and a right crankcase, the right crankcase is provided with a fixing seat on the side away from the left crankcase, the right crankcase is provided with a magneto, the magneto comprises a stator assembly sleeved on the crankshaft and a flywheel assembly sleeved on the stator assembly, the flywheel assembly is fixedly connected with the crankshaft, the fixing seat is provided with a fan fixedly connected with the flywheel assembly, the fixing seat is provided with the water tank radiator on the side away from the right crankcase, the water tank radiator is provided with a mounting column, the mounting column is provided with a rubber sleeve, the rubber sleeve is axially limited in the mounting column, the rubber sleeve is provided with a T-shaped bushing, the T-shaped bushing comprises a sleeve portion and a flat plate portion, the edge of the fixing seat is provided with a connecting protrusion, the right crankcase is screwed with a connecting column, the rod portion of the screw passes through the T-shaped bushing, the connecting protrusion and the connecting column, the flat plate portion is limited between the head portion of the screw and the rubber sleeve, and the connecting protrusion is limited between the rubber sleeve and the connecting column.

[0012] In the above-mentioned gasoline engine for motorcycle, the side wall of the cylinder body is provided with a mounting hole, an oil return hole and an oil inlet hole communicating with an oil supply pipeline, the mounting hole is provided with a tensioner assembly, the tensioner assembly comprises an outer shaft sleeve sliding in the mounting hole, an inner bushing sliding in the outer shaft sleeve and a compression spring I arranged between the outer shaft sleeve and the inner bushing, the inner end of the outer shaft sleeve protrudes out of the mounting hole to abut against a tensioning plate for pressing a timing chain, the inner cavity of the inner bushing is communicated with the oil inlet hole and the oil return hole, the inner cavity of the inner bushing and the inner cavity of the outer shaft sleeve are blocked and communicated through a one-way valve, the inner side wall of the outer shaft sleeve and the outer side wall of the inner bushing are left with an oil outlet gap I, and the outer side wall of the outer shaft sleeve and the hole wall of the mounting hole are left with an oil outlet gap II communicating with the oil outlet gap I.

[0013] In the motorcycle gasoline engine, the installation hole and the oil return hole are respectively arranged through the side wall of the cylinder body, the outer end of the oil inlet hole is arranged through the cylinder body, and the inner end is communicated with the oil supply pipeline, the outer side of the cylinder body is provided with a tension cover, the tension cover is arranged on the installation hole, the oil return hole and the oil inlet hole, and the tension cover is provided with an oil inlet channel communicated with the oil inlet hole and the inner cavity of the inner sleeve and an oil return channel communicated with the oil return hole and the inner cavity of the inner sleeve.

[0014] In the motorcycle gasoline engine, the tension cover comprises a cover body and a plug for plugging the outer end of the installation hole, the plug is hollow and has an open inner end, the outer end surface of the inner sleeve is in abutment and sealing with the inner end surface of the plug, the side wall of the plug is provided with an oil inlet small hole and an oil return small hole, the cover body and the cylinder body are provided with a sealing gasket sleeved outside the plug, the outer end surface of the cylinder body is concave to form an oil inlet groove and an oil return groove, the oil return groove is communicated with the oil return small hole and the oil return hole, the oil inlet groove is communicated with the oil inlet small hole, the inner surface of the cover body is concave to form an oil passing groove, the sealing gasket is provided with an oil passing hole one communicated with the oil inlet hole and the oil passing groove and an oil passing hole two communicated with the oil passing groove and the oil inlet groove, the oil passing hole one, the oil passing groove, the oil passing hole two, the oil inlet groove and the oil inlet small hole form the oil inlet channel, the oil return small hole is the oil return channel, the plug and the outer shaft sleeve are provided with an oil passing cavity communicated with the oil outlet gap one and the oil outlet gap two, the diameter of the oil inlet small hole is the same as that of the oil return small hole, the oil passing hole one is provided with a plurality of oil passing holes, and the diameter of the oil passing hole is smaller than that of the oil inlet small hole.

[0015] In the motorcycle gasoline engine, the cylinder head is provided with a combustion chamber and four valves, the inner wall of the combustion chamber is provided with four valve holes, and the four valves respectively plug and open the corresponding valve holes, the inner wall surface of the combustion chamber comprises an upper plane, a lower plane, a left plane and a right plane, two valve holes for intake are arranged on the upper plane, and two valve holes for exhaust are arranged on the lower plane, the included angle between the upper plane and the horizontal plane is the same as that between the lower plane and the horizontal plane, the included angle α between the upper plane and the lower plane is greater than 100° and less than 150°, the left plane and the right plane are mirror symmetric, and the included angle β between the two planes is less than 90°.

[0016] In the motorcycle gasoline engine, the upper end of the cylinder head is provided with an air inlet channel communicated with the two valve holes for intake, and the lower end of the cylinder head is provided with an exhaust channel communicated with the two valve holes for exhaust, the cylinder head is provided with a cooling water channel around the combustion chamber, the upper end of the cylinder head is provided with the cylinder head water outlet channel communicated with the cooling water channel, and the lower end of the cylinder head is provided with the cylinder head water inlet channel communicated with the cooling water channel, and the cylinder head water inlet channel is closely attached to the exhaust channel.

[0017] Compared with the prior art, the motorcycle gasoline engine has the following advantages:

[0018] 1. The present invention integrates the thermostat into the pump body, and arranges the main water inlet channel, small-circulation water inlet channel, large-circulation water outlet channel, and large-circulation water inlet channel in the pump body. No additional water pipe connections are required, resulting in a compact structure, small space occupation, a small number of parts, simple and convenient installation, and low cost. At the same time, the pump body is arranged on the side of the cylinder block, and the water tank radiator is arranged on the side of the crankcase body. The structure is compact, small space occupation, and the connecting pipes are short, effectively reducing the risk of water leakage and facilitating vehicle design.

[0019] 2. The present invention provides a fixing seat on one side of the right crankcase, and secures the water tank radiator to the fixing seat via a rubber sleeve, a T-shaped bushing, and screws. The rubber sleeve provides an all-round stress buffering effect, reducing the risk of rupture of the water tank radiator; the T-shaped bushing improves the force-bearing capacity of the rubber sleeve; at the same time, a fan fixedly connected to the flywheel assembly is provided in the fixing seat, effectively accelerating the heat dissipation speed of the water tank radiator. The fan is provided in the fixing seat, making the right crankcase structure simple and easy to process.

[0020] 3. The present invention arranges the tensioner assembly on the cylinder block, leaving a small space between the cylinder block and the tensioning plate, resulting in a small cylinder block and a small space occupation. Furthermore, the mounting hole is arranged on the side wall of the cylinder block, eliminating the need to insert the tensioner into the inner cavity of the cylinder block, thereby facilitating installation of the tensioner. Furthermore, an oil return hole is provided, one for inlet and one for outlet, so that the oil pressure entering the inner cavity of the inner sleeve remains stable. The oil in the inner cavity of the outer sleeve seeps through the first and second oil outlet gaps to the chamber where the timing chain is located. Damping is generated during the oil seepage process, thereby reducing some of the vibration caused by the movement of the timing chain and providing a buffering effect.

[0021] 4. The inner wall surface of the combustion chamber of the present invention includes an upper plane, a lower plane, a left plane and a right plane, all of which are flat. The angle α between the upper plane and the lower plane is greater than 100° and less than 150°, and the angle β between the left plane and the right plane is less than 90°, forming an extrusion-type combustion chamber with a small combustion chamber space, sufficient combustion and high efficiency. Description of the drawings:

[0022] Figure 1 It is a perspective view of the present invention;

[0023] Figure 2 The water pump of the present invention is a three-dimensional Figure 1 ;

[0024] Figure 3 The water pump of the present invention is a three-dimensional Figure 2 ;

[0025] Figure 4 is a cross-sectional view of a water pump of the present invention;

[0026] Figure 5is another perspective view of the water pump of the present invention;

[0027] Figure 6 is a perspective view of the water pump of the present invention;

[0028] Figure 7 is a perspective view of the water tank radiator and right crankcase body of the present invention Figure 1 ;

[0029] Figure 8 is a perspective view of the water tank radiator and right crankcase body of the present invention Figure 2 ;

[0030] Figure 9 is a perspective view of the water tank radiator and right crankcase body of the present invention;

[0031] Figure 10 is a perspective view of the water tank radiator of the present invention;

[0032] Figure 11 is a perspective view of the right crankcase body, cylinder block, tensioner assembly and cylinder head of the present invention;

[0033] Figure 12 is a perspective view of the cylinder block of the present invention;

[0034] Figure 13 is a perspective view of the gasket of the present invention;

[0035] Figure 14 is a perspective view of the tensioner cap of the present invention;

[0036] Figure 15 is a perspective view of the cylinder head of the present invention;

[0037] Figure 16 is a perspective view of the cylinder head, valve and pump body of the present invention;

[0038] Figure 17 is a front view of the cylinder head and valve of the present invention;

[0039] Figure 18 is Figure 17 a sectional view along the line A-A;

[0040] Figure 19 is Figure 17 a sectional view along the line B-B.

[0041] 1, crankcase; 1a, left crankcase; 1b, right crankcase; 2, cylinder block; 3, cylinder head; 4, radiator; 4a, upper water chamber; 4b, lower water chamber; 4c, core; 5, pump body; 5a, pump shell one; 5b, pump shell two; 6, pump cavity; 7, impeller; 8, total water inlet channel; 9, mounting cavity; 9a, cavity one; 9b, cavity two; 10, small circulation water inlet channel; 11, large circulation water outlet channel; 12, large circulation water inlet channel; 13, pump water outlet channel; 14, thermostat; 14a, bracket one; 14b, bracket two; 14c, valve core assembly; 15, cylinder head water outlet channel; 16, radiator water inlet channel; 17, radiator water outlet channel; 18, cylinder head water inlet channel; 19, large circulation water outlet pipe; 20, large circulation water inlet pipe; 21, total water inlet pipe; 22, pump water outlet pipe; 23, radiator water inlet pipe; 24, radiator water outlet pipe; 25, cylinder head water outlet pipe; 26, cylinder head water inlet pipe; 27, mounting boss; 28, pump shaft; 29, camshaft; 30, crankshaft; 31, fixing seat; 32, magneto; 32a, stator assembly; 32b, flywheel assembly; 33, fan; 34, air guide strip; 35, mounting column; 36, rubber sleeve; 37, T-shaped bushing; 37a, sleeve part; 37b, flat plate part; 38, connecting convex edge; 39, connecting column; 40, mounting hole; 41, oil return hole; 42, oil inlet hole; 43, outer shaft sleeve; 44, inner bushing; 45, compression spring one; 46, timing chain; 47, tensioning plate; 48, tensioning cover; 48a, cover body; 48b, plug; 49, oil inlet small hole; 50, oil return small hole; 51, sealing gasket; 52, oil inlet groove; 53, oil return groove; 54, oil passing groove; 55, oil passing hole one; 56, oil passing hole two; 57, oil passing cavity; 58, combustion chamber; 58a, upper plane; 58b, lower plane; 58c, left plane; 58d, right plane; 58e, arc surface; 59, valve; 60, valve hole; 61, air inlet channel; 62, exhaust channel; 63, cooling water channel; 64, mounting pipe; 65, temperature sensor; 66, guard cover; 67, mounting strip; 68, oil outlet hole; 69, steel ball; 70, limiting frame; 71, compression spring two; 72, check ring; 73, mounting part; 74, front end face. DETAILED DESCRIPTION

[0042] The application will be further described in the following specific examples, referring to Figure 1 -19:

[0043] A gasoline engine for motorcycle comprises a crankcase 1, a cylinder body 2 and a cylinder head 3 arranged in sequence, the crankcase 1 is provided with a water tank radiator 4, the cylinder head 3 is provided with a pump body 5, the pump body 5 is provided with a pump cavity 6, a total water inlet channel 8, a mounting cavity 9, a small circulation water inlet channel 10, a large circulation water outlet channel 11, a large circulation water inlet channel 12 and a pump water outlet channel 13, the pump cavity 6 is provided with an impeller 7, the mounting cavity 9 is provided with a thermostat 14, the thermostat 14 divides the mounting cavity 9 into two chambers, i.e., a chamber one 9a and a chamber two 9b, the total water inlet channel 8 is connected with a cylinder head water outlet channel 15 of the cylinder head 3 and the chamber one 9a, the small circulation water inlet channel 10 is connected with the chamber one 9a and the pump cavity 6, the large circulation water outlet channel 11 is connected with the chamber two 9b and a water tank water inlet channel 16 of the water tank radiator 4, the large circulation water inlet channel 12 is connected with a water tank water outlet channel 17 of the water tank radiator 4 and the pump cavity 6, and the pump water outlet channel 13 is connected with the pump cavity 6 and a cylinder head water inlet channel 18 of the cylinder head 3, when the temperature does not reach the set value, the thermostat 14 disconnects the connection between the chamber one 9a and the chamber two 9b, and when the temperature reaches the set value, the thermostat 14 connects the chamber one 9a and the chamber two 9b.

[0044] The working principle of the present application is as shown in the drawings, Figures 1-19 when the temperature does not reach the set value, the thermostat 14 disconnects the connection between the chamber one 9a and the chamber two 9b, and the water in the cylinder head water outlet channel 15 enters the pump cavity 6 through the total water inlet channel 8, the chamber one 9a and the small circulation water inlet channel 10 to form a small circulation, when the temperature reaches the set value, the thermostat 14 connects the chamber one 9a and the chamber two 9b, the water in the cylinder head water outlet channel 15 enters the pump cavity 2 through the total water inlet channel 8, the chamber one 9a, the chamber two 9b, the large circulation water outlet channel 11, the water tank water inlet channel 16, the water tank radiator 4, the water tank water outlet channel 17, the large circulation water inlet channel 12 to form a large circulation, and a small part of the water enters the pump cavity 2 through the small circulation water inlet channel 10. The water in the pump cavity 2 enters the cylinder head 3 through the pump water outlet channel 13 and the cylinder head water inlet channel 18 to cool the cylinder head 3.

[0045] The present application integrates the thermostat 14 in the pump body 5, and sets the total water inlet channel 8, the small circulation water inlet channel 10, the large circulation water outlet channel 11 and the large circulation water inlet channel 12 in the pump body 5, without the need of additional water pipes, so that the structure is compact, the space occupied is small, the number of parts is small, the installation is simple and convenient, and the cost is low. At the same time, the pump body 5 is arranged at the side of the cylinder body 3, and the water tank radiator 4 is arranged at the side of the crankcase 1, so that the structure is compact, the space occupied is small, and the connecting pipeline is short, which effectively reduces the risk of water leakage and facilitates the design of the whole vehicle.

[0046] The specific structure of the pump body 5 and the specific mounting structure of the water tank radiator 4 and the cylinder head 3 are as shown in the drawings, Figures 1-5, 7, 8, 10, 15-17, the pump body 5 comprises pump shell one 5a and pump shell two 5b, the middle part of the pump body 5 forms the pump cavity 6, the upper end forms the installation cavity 9, the small circulation water inlet channel 10 is arranged between the pump shell one 5a and the pump shell two 5b, the upper end of the pump shell one 5a is integrally formed with the large circulation water outlet pipe 19 with the large circulation water outlet channel 11, the middle part is integrally formed with the large circulation water inlet pipe 20 with the large circulation water inlet channel 12, the upper end of the pump shell two 5b is integrally formed with the total water inlet pipe 21 with the total water inlet channel 8, the lower end is integrally formed with the pump water outlet pipe 22 with the pump water outlet channel 13, the upper end of the water tank radiator 4 is integrally formed with the water tank water inlet pipe 23 with the water tank water inlet channel 16, the lower end is integrally formed with the water tank water outlet pipe 24 with the water tank water outlet channel 17, the large circulation water outlet pipe 19 is connected with the water tank water inlet pipe 23 through a pipeline, the large circulation water inlet pipe 20 is connected with the water tank water outlet pipe 24 through a pipeline, the upper end of the cylinder head 3 is integrally formed with the cylinder head water outlet pipe 25 with the cylinder head water outlet channel 15, the lower end is integrally formed with the cylinder head water inlet pipe 26 with the cylinder head water inlet channel 18, the total water inlet pipe 21 is inserted into the cylinder head water outlet pipe 25, and the pump water outlet pipe 22 is inserted into the cylinder head water inlet pipe 26.

[0047] The connecting structure of the pump shell one 5a and the pump shell two 5b: the pump shell one 5a and the pump shell two 5b are fixedly connected through screws.

[0048] In order to detect the temperature of the total water inlet pipe 21 and further improve the integration degree, the total water inlet pipe 21 is integrally formed with a mounting pipe 64, and a temperature sensor 65 for detecting the water temperature of the total water inlet pipe 21 is mounted on the mounting pipe 64.

[0049] In order to further make the motorcycle engine structure compact, the end of the pump shell two 5b away from the pump shell one 5a is provided with a mounting boss 27 matched with the assembly hole on the cylinder head 3, a pump shaft 28 coaxial with the mounting boss 27 and extending out of the mounting boss 27 is rotationally arranged in the pump body 5, one end of the pump shaft 28 is connected with the impeller 7, and the other end is connected with a cam shaft 29 arranged in the cylinder head 3, and the end of the pump shell two 5b away from the pump shell one 5a is provided with a mounting platform matched with the mounting plane on the cylinder body 3, and the mounting boss 27 is arranged in the mounting platform, so that the mounting is facilitated.

[0050] The mounting structure of the pump shaft 28: the pump shaft 28 is rotationally connected with the mounting boss 27 through two bearings, and an integrated water seal is arranged between the impeller 7 and the bearing between the pump shell two 5b and the pump shaft 28, and an oil seal is arranged between the integrated water seal and the bearing between the pump shaft 28 and the mounting boss 27.

[0051] Structure of thermostat 14: As shown in Figure 4 the bracket 14a is connected with the end of bracket 14b, and the end of bracket 14b is provided with an annular part, and the edge of the annular part is turned outward to form a mounting protrusion which is clamped between the pump shell 5a and the pump shell 5b, and the middle part of the annular part is formed with a valve port, the valve core assembly 14c includes a mounting sleeve, a temperature sensing element arranged in the mounting sleeve, a push rod slidingly arranged in the mounting sleeve, a valve plate connected with the end of the mounting sleeve, and a spring arranged between the bracket 14b and the valve plate, the end of the push rod close to the bracket 14a protrudes from the mounting sleeve and abuts against the bracket 14a, and the other end abuts against the temperature sensing element, when the temperature rises, the temperature sensing element expands, the push rod protrudes from the mounting sleeve, the mounting sleeve and the valve plate move away from the end of the bracket 14a, the spring is compressed, the valve plate opens the valve port, and the chamber 9a and the chamber 9b are communicated; when the temperature drops, under the elastic force of the spring, the mounting sleeve and the valve plate move to the side of the bracket 14a until the valve plate blocks the valve port, and the chamber 9a and the chamber 9b are disconnected.

[0052] In order to avoid the temperature sensing element from leaving the mounting sleeve, the end of the push rod close to the temperature sensing element is sleeved with a rubber pipe, the rubber pipe is fixedly connected with the mounting sleeve through a sealing seat, and the rubber pipe blocks the mounting sleeve, and the sealing seat is provided with a through hole for the push rod to protrude.

[0053] Preferably, the temperature sensing element is solid, liquid or gas. In this embodiment, the temperature sensing element is solid paraffin.

[0054] Mounting structure of water tank radiator 4: As shown in Figures 6-10As shown, the crankcase 1 is provided with a crankshaft 30, the crankcase 1 comprises a left crankcase 1a and a right crankcase 1b, the right crankcase 1b is provided with a fixing base 31 on the side away from the left crankcase 1a, the right crankcase 1b is provided with a magneto 32, the magneto 32 comprises a stator assembly 32a sleeved on the crankshaft 30 and a flywheel assembly 32b sleeved on the stator assembly 32a, the flywheel assembly 32b is fixedly connected with the crankshaft 30, the fixing base 31 is provided with a fan 33 fixedly connected with the flywheel assembly 32b, the fixing base 31 is provided with the water tank radiator 4 on the side away from the right crankcase 1b, the water tank radiator 4 is provided with a mounting column 35, the mounting column 35 is provided with a rubber sleeve 36, the rubber sleeve 36 is axially limited in the mounting column 35, the rubber sleeve 36 is provided with a T-shaped bushing 37, the T-shaped bushing 37 comprises a sleeve part 37a and a flat plate part 37b, the edge of the fixing base 31 is provided with a connecting convex edge 38, the right crankcase 1b is screwed with a connecting column 39, the rod of the screw is screwed with the connecting column 39 through the T-shaped bushing 37 and the connecting convex edge 38, the flat plate part 37b is limited between the head of the screw and the rubber sleeve 36, and the connecting convex edge 38 is limited between the rubber sleeve 36 and the connecting column 39.

[0055] The fixing base 31 is arranged on the side of the right crankcase 1b, the water tank radiator 4 is fixedly arranged on the fixing base 31 through the rubber sleeve 36, the T-shaped bushing 37 and the screw, the rubber sleeve 36 is arranged to buffer stress in all directions and reduce the risk of water tank radiator 4 breaking, the T-shaped bushing 37 is arranged to improve the stress capacity of the rubber sleeve 36, meanwhile, the fan 33 fixedly connected with the flywheel assembly 32b is arranged in the fixing base 31, so that the heat dissipation speed of the water tank radiator 4 is effectively accelerated, and the right crankcase 1b is simple in structure and convenient to process.

[0056] Preferably, the material of the T-shaped bushing 37 is copper, steel or cast iron.

[0057] The axial limiting structure of the rubber sleeve 36 and the mounting column 35 is as shown in the figure. Figure 9 The inside of the connecting column 39 is provided with an annular part, the outside wall of the rubber sleeve 36 is concave to form an annular groove, and the rubber sleeve 36 is axially limited in the mounting column 35 through the annular part arranged in the annular groove.

[0058] In order to facilitate the air flow driven by the fan 33, the lower part and the side edge of the fixing base 31 are provided with communicating notches, and the notches are provided with a plurality of air guide strips 34.

[0059] The specific structure of the flywheel assembly 32b and the mounting structure of the fan 33: the flywheel assembly 32b comprises a shell, a magnetic steel arranged in the shell, and a wheel sleeve fixed in the middle of the shell, the wheel sleeve is fixedly connected with the crankshaft 30, and the fan 33 is fixedly connected on the shell.

[0060] The specific structure of the water tank radiator 4 and the mounting structure: the mounting column 35 is provided with a plurality of mounting columns, the water tank radiator 4 comprises an upper water chamber 4a, a lower water chamber 4b, and a core 4c arranged between the upper water chamber 4a and the lower water chamber 4b, the edges of the upper water chamber 4a and the lower water chamber 4b are respectively provided with mounting plates, and the mounting plates are provided with the mounting columns 35.

[0061] Further, the water tank inlet pipe 23 is in an integral structure with the upper water chamber 4a, and the water tank outlet pipe 24 is in an integral structure with the lower water chamber 4b.

[0062] In order to protect the water tank radiator 4, the water tank radiator 4 is provided with a protective cover 66, the protective cover 66 is fixedly connected on the mounting protruding edge of the fixed seat 31 by screws, the fixed seat 31 protrudes towards the side of the water tank radiator 4 and is provided with a mounting strip 67 abutting against the protective cover 66, and the mounting protruding edge is arranged outside the mounting strip 67.

[0063] The structure of the tensioner assembly: as shown in Figures 11-14 The mounting hole 40 is provided with a tensioner assembly, the tensioner assembly comprises an outer shaft sleeve 43 slidingly arranged in the mounting hole 40, an inner bushing 44 slidingly arranged in the outer shaft sleeve 43, and a compression spring 45 arranged between the outer shaft sleeve 43 and the inner bushing 44, the inner end of the outer shaft sleeve 43 protrudes out of the mounting hole 40 and abuts against a tensioning plate 47 for pressing a timing chain 46, the inner cavity of the inner bushing 44 is communicated with the oil inlet hole 42 and the oil return hole 41, the inner cavity of the inner bushing 44 is communicated with the inner cavity of the outer shaft sleeve 43 through a one-way valve, and an oil outlet gap one is left between the inner wall of the outer shaft sleeve 43 and the outer wall of the inner bushing 44, and an oil outlet gap two is left between the outer wall of the outer shaft sleeve 43 and the hole wall of the mounting hole 40 and communicated with the oil outlet gap one.

[0064] The working principle of the tensioner assembly of the application: as shown in Figures 11-14As shown, the oil in the crankcase 1 is pumped into the oil supply pipeline by the oil pump, then enters the inner cavity of the inner bushing 44 through the oil inlet hole 42, part of the oil opens the one-way valve and flows into the inner cavity of the outer shaft sleeve 43, so that the outer shaft sleeve 43 extends inward and tightens the timing chain 46 through the tension plate 47, and the other part of the oil flows out through the oil return hole 41 to the chamber where the timing chain 46 is located, and finally returns to the crankcase 1. The oil return hole 41 is set to enter and exit, so that the oil pressure in the inner cavity of the inner bushing 44 remains stable, and the oil in the inner cavity of the outer shaft sleeve 43 seeps out to the chamber where the timing chain 46 is located through the oil outlet gap one and the oil outlet gap two. In the process of oil seepage, damping will be generated, which can reduce a part of the vibration caused by the movement of the timing chain 46, and plays a buffering role.

[0065] The tensioner assembly is arranged on the cylinder block 2, the space between the cylinder block 2 and the tension plate 47 is small, the cylinder block has small volume and occupies small space, the mounting hole 40 is arranged on the side wall of the cylinder block 2, the tensioner does not need to extend into the inner cavity of the cylinder block 2 for installation, and the installation of the tensioner is facilitated; the compression spring one 45 is arranged for low-pressure pre-tightening, that is, when the low pressure is low, the outer shaft sleeve 43 is pressed against the timing chain 46 through the tension plate 47 under the elastic force of the compression spring one 45.

[0066] In the above-mentioned motorcycle gasoline engine, the mounting hole 40 and the oil return hole 41 are arranged through the side wall of the cylinder block 2 respectively, the outer end of the oil inlet hole 42 is arranged through the cylinder block 2 and the inner end is communicated with the oil supply pipeline, the outer side of the cylinder block 2 is provided with a tension cover 48, the tension cover 48 is arranged on the mounting hole 40, the oil return hole 41 and the oil inlet hole 42, and the tension cover 48 is provided with an oil inlet channel communicated with the oil inlet hole 42 and the inner cavity of the inner bushing 44, and an oil return channel communicated with the oil return hole 41 and the inner cavity of the inner bushing 44.

[0067] Specific structure of the tensioner cover 48 and the cylinder block 2, and the mounting structure: the tensioner cover 48 includes a cover body 48a and a plug 48b for plugging the outer end of the mounting hole 40, the plug 48b is hollow and the inner end is open, the outer end surface of the inner liner 44 is in abutting sealing with the inner end surface of the plug 48b, the side wall of the plug 48b is provided with an oil inlet small hole 49 and an oil return small hole 50, a sealing gasket 51 is arranged between the cover body 48a and the cylinder block 2 and is sleeved outside the plug 48b, the outer end surface of the cylinder block 2 is concave to form an oil inlet groove 52 and an oil return groove 53, the oil return groove 53 is communicated with the oil return small hole 50 and the oil return hole 41, the oil inlet groove 52 is communicated with the oil inlet small hole 49, the inner surface of the cover body 48a is concave to form an oil passing groove 54, the sealing gasket 51 is provided with an oil passing hole one 55 communicated with the oil inlet hole 42 and the oil passing groove 54 and an oil passing hole two 56 communicated with the oil passing groove 54 and the oil inlet groove 52, the oil passing hole one 55, the oil passing groove 54, the oil passing hole two 56, the oil inlet groove 52 and the oil inlet small hole 49 form the oil inlet channel, the oil return small hole 50 is the oil return channel, the plug 48b and the outer shaft sleeve 43 are provided with an oil passing cavity 57 communicated with the oil outlet gap one and the oil outlet gap two, the diameter of the oil inlet small hole 49 is the same as that of the oil return small hole 50, the oil passing hole one 55 is provided with a plurality of oil passing holes and the diameter is smaller than that of the oil inlet small hole 49, so as to filter the oil entering the oil inlet small hole 49 and avoid the oil inlet small hole 49 and the oil return small hole 50 being blocked. The oil passage design of the tensioner assembly of the application is ingenious, which is convenient for processing and mounting.

[0068] Mounting structure of the tensioner cover 48: the tensioner cover 48 is fixedly connected on the cylinder block 2 by screws.

[0069] Specific structure of the one-way valve: the inner liner 44 is hollow and the outer end is open, the inner end of the inner liner 44 is provided with an oil outlet hole 68 communicated with the inner cavity of the inner liner 44 and the inner cavity of the outer shaft sleeve 43, the one-way valve includes a steel ball 69 for plugging and opening the oil outlet hole 68, the steel ball 69 is located outside the inner end of the inner liner 44, the inner liner 44 is provided with a limiting frame 70 for limiting the steel ball 69, and the steel ball 69 and the limiting frame 70 are provided with a compression spring two 71 for moving the steel ball 69 to the side of the oil outlet hole 68.

[0070] In order to limit the movement of the outer shaft sleeve 43 relative to the inner liner 44, the inner side wall of the outer shaft sleeve 43 is concave to form an annular groove, the outer sleeve of the inner liner 44 is provided with a check ring 72, the check ring 72 is in abutting limiting with the end surface of the annular groove close to the tensioner cover 48, and the inner end of the inner liner 44 is in abutting limiting with the end surface of the annular groove away from the tensioner cover 48.

[0071] In order to reduce the overall thickness of the side wall of the cylinder body 2 and reduce the weight of the cylinder body 2, a mounting portion 73 with an outer surface protruding from the cylinder body 2 is provided on the side wall of the cylinder body 2, and the mounting hole 40, the oil return hole 41 and the oil inlet hole 42 are all arranged in the mounting portion 73.

[0072] Furthermore, one end of the timing chain 46 is connected to the crankshaft 30 and the other end is connected to the camshaft 29. The oil supply pipeline includes a pipeline 1 arranged in the cylinder body 2 and a pipeline 2 arranged in the cylinder head 3. The pipeline 1 connects the inner cavity of the crankcase 1 and the pipeline 2, and the inner end of the oil inlet hole 42 is connected to the pipeline 1.

[0073] The structure of the combustion chamber 58 is as follows: Figures 15-19 As shown, the cylinder head 3 is provided with a combustion chamber 58 and four valves 59, and four valve holes 60 are provided on the inner wall of the combustion chamber 58. The four valves 59 respectively block and open the corresponding valve holes 60. The inner wall surface of the combustion chamber 58 includes an upper plane 58a, a lower plane 58b, a left plane 58c and a right plane 58d. The two valve holes 60 for intake are provided on the upper plane 58a, and the two valve holes 60 for exhaust are provided on the lower plane 58b. The angle between the upper plane 58a and the horizontal plane is the same as the angle between the lower plane 58b and the horizontal plane. The angle α between the upper plane 58a and the lower plane 58b is greater than 100° and less than 150°. The left plane 58c and the right plane 58d are mirror-symmetrical, and the angle β between the two planes is less than 90°.

[0074] like Figures 15-19 As shown, the inner wall surface of the combustion chamber 58 of the present invention includes an upper plane 58a, a lower plane 58b, a left plane 58c and a right plane 8, all of which are planes. The angle α between the upper plane 58a and the lower plane 58b is greater than 100° and less than 150°, and the angle β between the left plane 58c and the right plane 58d is less than 90°, forming an extrusion-type combustion chamber. The combustion chamber 58 has a small space, sufficient combustion and high efficiency.

[0075] In order to achieve more complete combustion and further improve efficiency, the upper plane 58a and the lower plane 58b are connected by an arc surface 58e. The maximum distance H between the arc surface 58e and the front end surface 74 of the combustion chamber 58 is 8mm-10mm.

[0076] In order to stabilize the engine temperature performance, the upper end of the cylinder head 3 is provided with an air inlet passage 61, the air inlet passage 61 is communicated with two air valve holes 60 for air inlet, the lower end of the cylinder head 3 is provided with an exhaust passage 62, the exhaust passage 62 is communicated with two air valve holes 60 for air outlet, the cylinder head 3 is provided with a cooling water channel 63 around the combustion chamber 58, the upper end of the cylinder head 3 is provided with the cylinder head water outlet passage 15 communicated with the cooling water channel 63, the lower end of the cylinder head 3 is provided with the cylinder head water inlet passage 18 communicated with the cooling water channel 63, the cylinder head water inlet passage 18 is closely attached to the exhaust passage 62, the temperature of the exhaust passage 62 is the highest, the cylinder head water inlet passage 18 can effectively cool the exhaust passage 62, and then effectively cool the cylinder head 3. The cooling water channel is optimally designed, and the cooling is reliable.

[0077] The above embodiment is only one of the preferred embodiments of the present application, and does not limit the scope of the present application, so: any equivalent changes made according to the shape, structure, principle of the present application should be covered within the protection scope of the present application.

Claims

1. A gasoline engine for a motorcycle, comprising a crankcase (1), a cylinder block (2) and a cylinder head (3) arranged in sequence, characterized in that: A water tank radiator (4) is provided on the side of the crankcase (1), and a pump body (5) is provided on the side of the cylinder head (3). The pump body (5) is provided with a pump chamber (6), a total water inlet channel (8), an installation chamber (9), a small circulation water inlet channel (10), a large circulation water outlet channel (11), a large circulation water inlet channel (12) and a pump outlet channel (13). An impeller (7) is provided in the pump chamber (6), and a thermostat (14) is installed in the installation chamber (9). The thermostat (14) divides the installation chamber (9) into two chambers, chamber 1 (9a) and chamber 2 (9b). The total water inlet channel (8) is connected to the cylinder head water outlet channel (15) and the chamber (11) of the cylinder head (3). The first chamber (9a) is connected to the second chamber (9a), the small circulation water inlet channel (10) is connected to the pump chamber (6), the large circulation water outlet channel (11) is connected to the second chamber (9b) and the water tank water inlet channel (16) of the water tank radiator (4), the large circulation water inlet channel (12) is connected to the water tank water outlet channel (17) of the water tank radiator (4) and the pump chamber (6), the pump water outlet channel (13) is connected to the pump chamber (6) and the cylinder head water inlet channel (18) of the cylinder head (3), when the temperature does not reach the set value, the thermostat (14) disconnects the connection between the first chamber (9a) and the second chamber (9b); when the temperature reaches the set value, the thermostat (14) connects the first chamber (9a) and the second chamber (9b).

2. A gasoline engine for motorcycle according to claim 1, characterized in that: The pump body (5) comprises a pump housing (5a) and a pump housing (5b). The pump cavity (6) is formed in the middle of the pump body (5) and the installation cavity (9) is formed at the upper end. The small circulation water inlet channel (10) is arranged between the pump housing (5a) and the pump housing (5b). The upper end of the pump housing (5a) is integrally formed with a large circulation water outlet pipe (19) having a large circulation water outlet channel (11), and the middle part is integrally formed with a large circulation water inlet pipe (20) having a large circulation water inlet channel (12). The upper end of the pump housing (5b) is integrally formed with a main water inlet pipe (21) having a main water inlet channel (8), and the lower end is integrally formed with a pump outlet pipe (22) having a pump outlet channel (13). The water tank heat dissipation The upper end of the device (4) is integrally formed with a water tank inlet pipe (23) having a water tank inlet channel (16), and the lower end is integrally formed with a water tank outlet pipe (24) having a water tank outlet channel (17); the large circulation outlet pipe (19) is connected to the water tank inlet pipe (23) through a pipe, and the large circulation inlet pipe (20) is connected to the water tank outlet pipe (24) through a pipe; the upper end of the cylinder head (3) is integrally formed with a cylinder head outlet pipe (25) having a cylinder head outlet channel (15), and the lower end is integrally formed with a cylinder head inlet pipe (26) having a cylinder head inlet channel (18); the main water inlet pipe (21) is inserted into the cylinder head outlet pipe (25), and the pump outlet pipe (22) is inserted into the cylinder head inlet pipe (26).

3. A gasoline engine for motorcycle according to claim 2, characterized in that: The end of the pump housing 2 (5b) away from the pump housing 1 (5a) is provided with a mounting boss (27) that matches the assembly hole on the cylinder head (3); a pump shaft (28) is rotatably provided in the pump body (5) and is coaxial with the mounting boss (27) and has one end extending out of the mounting boss (27); one end of the pump shaft (28) is connected to the impeller (7) and the other end is connected to a camshaft (29) provided in the cylinder head (3); the end of the pump housing 2 (5b) away from the pump housing 1 (5a) is provided with a mounting platform that matches the mounting plane on the cylinder body (3); and the mounting boss (27) is provided in the mounting platform.

4. A gasoline engine for motorcycle according to claim 1, characterized in that: The thermostat (14) includes a bracket (14a), a bracket (14b) with one end mounted on the bracket (14a), and a valve core assembly (14c) slidably arranged between the bracket (14a) and the bracket (14b), wherein the end of the bracket (14a) connected to the bracket (14b) is provided with an annular portion, and the edge of the annular portion is turned outward to form a mounting convex edge that is clamped between the pump housing (5a) and the pump housing (5b), and the middle of the annular portion forms a valve port, and the valve core assembly (14c) includes a mounting sleeve, a temperature sensing element arranged in the mounting sleeve, a push rod slidably arranged in the mounting sleeve, a valve plate connected to the end of the mounting sleeve, And a spring is arranged between the second bracket (14b) and the valve plate, the end of the push rod close to the first bracket (14a) extends out of the mounting sleeve to abut against the first bracket (14a), and the other end abuts against the temperature sensing element. When the temperature rises, the temperature sensing element expands, the push rod extends out of the mounting sleeve, and the mounting sleeve and the valve plate move toward the end away from the first bracket (14a). The spring is compressed, the valve plate opens the valve port, and the chamber one (9a) and the chamber two (9b) are connected; when the temperature drops, under the elastic force of the spring, the mounting sleeve and the valve plate move toward the side of the first bracket (14a) until the valve plate blocks the valve port, and the chamber one (9a) and the chamber two (9b) are disconnected.

5. A gasoline engine for motorcycle according to claim 1, characterized in that: A crankshaft (30) is provided in the crankcase (1), and the crankcase (1) comprises a left crankcase (1a) and a right crankcase (1b). A fixing seat (31) is installed on a side of the right crankcase (1b) away from the left crankcase (1a). A magneto (32) is provided in the right crankcase (1b). The magneto (32) comprises a stator assembly (32a) sleeved outside the crankshaft (30) and a flywheel assembly (32b) sleeved outside the stator assembly (32a). The flywheel assembly (32b) is fixedly connected to the crankshaft (30). A fan (33) fixedly connected to the flywheel assembly (32b) is provided in the fixing seat (31). The water tank radiator is provided on a side of the fixing seat (31) away from the right crankcase (1b). (4), a mounting column (35) is provided on the water tank radiator (4), a rubber sleeve (36) is provided in the mounting column (35), the rubber sleeve (36) is axially limited in the mounting column (35), a T-shaped bushing (37) is provided in the rubber sleeve (36), the T-shaped bushing (37) includes a sleeve portion (37a) and a flat plate portion (37b), the edge of the fixing seat (31) is provided with a connecting ridge (38), a connecting column (39) is screwed on the right crankcase body (1b), the rod of the screw passes through the T-shaped bushing (37), the connecting ridge (38) is screwed to the connecting column (39), the flat plate portion (37b) is limited between the head of the screw and the rubber sleeve (36), and the connecting ridge (38) is limited between the rubber sleeve (36) and the connecting column (39).

6. A gasoline engine for motorcycle according to claim 1, characterized in that: The side wall of the cylinder body (2) is provided with a mounting hole (40), an oil return hole (41), and an oil inlet hole (42) connected to the oil supply line. A tensioner assembly is provided in the mounting hole (40). The tensioner assembly includes an outer sleeve (43) slidably arranged in the mounting hole (40), an inner sleeve (44) slidably arranged in the outer sleeve (43), and a compression spring (45) arranged between the outer sleeve (43) and the inner sleeve (44). The inner end of the outer sleeve (43) extends out of the mounting hole. (40) abuts against a tensioning plate (47) for compressing a timing chain (46); the inner cavity of the inner sleeve (44) is connected to the oil inlet hole (42) and the oil return hole (41); the inner cavity of the inner sleeve (44) and the inner cavity of the outer sleeve (43) are blocked and connected through a one-way valve; an oil outlet gap 1 is left between the inner side wall of the outer sleeve (43) and the outer side wall of the inner sleeve (44); an oil outlet gap 2 connected to the oil outlet gap 1 is left between the outer side wall of the outer sleeve (43) and the hole wall of the mounting hole (40).

7. A gasoline engine for motorcycle according to claim 6, characterized in that: The mounting hole (40) and the oil return hole (41) are respectively arranged through the side wall of the cylinder body (2); the outer end of the oil inlet hole (42) penetrates the cylinder body (2) and the inner end is connected to the oil supply pipeline; a tensioning cover (48) is provided on the outer side of the cylinder body (2); the tensioning cover (48) is provided on the mounting hole (40), the oil return hole (41) and the oil inlet hole (42); an oil inlet channel connecting the oil inlet hole (42) and the inner cavity of the inner sleeve (44) and an oil return channel connecting the oil return hole (41) and the inner cavity of the inner sleeve (44) are provided between the tensioning cover (48) and the cylinder body (2).

8. A gasoline engine for motorcycle according to claim 7, characterized in that: The tensioning cover (48) includes a cover body (48a) and a plug (48b) for sealing the outer end of the mounting hole (40). The plug (48b) is hollow and has an inner end open. The outer end surface of the inner sleeve (44) is in contact with the inner end surface of the plug (48b) for sealing. An oil inlet hole (49) and an oil return hole (50) are provided through the side wall of the plug (48b). A sealing gasket (51) is provided between the cover body (48a) and the cylinder body (2) and is sleeved on the outside of the plug (48b). The outer end surface of the cylinder body (2) is concave to form an oil inlet groove (52) and an oil return groove (53). The oil return groove (53) is connected to the oil return hole (50) and the oil return hole (41). The oil inlet groove (52) is connected to the oil inlet hole (49). The inner surface of the cover body (48a) is provided with a plurality of sealing rings. The surface is concave to form an oil-passing groove (54); the sealing gasket (51) is provided with an oil-passing hole (55) connecting the oil inlet hole (42) and the oil-passing groove (54); and an oil-passing hole (56) connecting the oil-passing groove (54) and the oil-inlet groove (52); the oil-passing hole (55), the oil-passing groove (54), the oil-passing hole (56), the oil-inlet groove (52) and the oil-inlet hole (49) form the oil-inlet passage; the oil-returning hole (50) is the oil-returning passage; an oil-passing cavity (57) connecting the oil-outlet gap (1) and the oil-outlet gap (2) is provided between the plug (48b) and the outer sleeve (43); the diameter of the oil-inlet hole (49) is the same as the diameter of the oil-returning hole (50); a plurality of oil-passing holes (55) are provided, and the diameter is smaller than the diameter of the oil-inlet hole (49).

9. The gasoline engine for motorcycle according to claim 1, characterized in that: The cylinder head (3) is provided with a combustion chamber (58) and four valves (59). Four valve holes (60) are provided on the inner wall of the combustion chamber (58). The four valves (59) respectively block and open the corresponding valve holes (60). The inner wall surface of the combustion chamber (58) includes an upper plane (58a), a lower plane (58b), a left plane (58c) and a right plane (58d). The two valve holes (60) for air intake are provided on the upper plane (58a), and the two valve holes (60) for exhaust are provided on the lower plane (58b). The angle between the upper plane (58a) and the horizontal plane is the same as the angle between the lower plane (58b) and the horizontal plane. The angle α between the upper plane (58a) and the lower plane (58b) is greater than 100° and less than 150°. The left plane (58c) and the right plane (58d) are mirror-symmetrical, and the angle β between the two planes is less than 90°.

10. A gasoline engine for motorcycle according to claim 9, characterized in that: An intake channel (61) is provided at the upper end of the cylinder head (3), and the intake channel (61) is connected to two valve holes (60) for intake. An exhaust channel (62) is provided at the lower end of the cylinder head (3), and the exhaust channel (62) is connected to the two valve holes (60) for exhaust. A cooling water channel (63) is provided in the cylinder head (3) around the combustion chamber (58). The upper end of the cylinder head (3) is provided with a cylinder head water outlet channel (15) connected to the cooling water channel (63), and the lower end is provided with a cylinder head water inlet channel (18) connected to the cooling water channel (63). The cylinder head water inlet channel (18) is closely attached to the exhaust channel (62).

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