Power assembly and motorcycle adopting the same

Abstract

This application discloses a powertrain and a motorcycle using the powertrain. The powertrain includes a housing, a crankshaft, and a piston. The housing includes a crankcase and a cylinder block connected to the crankcase. The cylinder block has a cylinder bore and a cylinder water jacket. The cylinder water jacket is arranged around the cylinder bore and includes a first sidewall near the cylinder bore and a second sidewall away from the cylinder bore. A water channel for coolant passage is formed between the first and second sidewalls. The crankshaft is located in the crankcase and rotatably connected to the crankcase. The piston is at least partially located in the cylinder bore and drively connected to the crankshaft. Both the first and second sidewalls are arc-shaped and arranged around the centerline of the cylinder bore. The first sidewall protrudes radially along the cylinder bore to form a protrusion. The distance between the first and second sidewalls is greater than the distance between the first sidewall and the protrusion. The motorcycle includes the above-described powertrain. This arrangement improves the cooling efficiency of the coolant to the cylinder block.

Description

Technical Field

[0001] This application relates to the field of vehicle technology, and in particular to a powertrain and a motorcycle using the powertrain. Background Technology

[0002] Motorcycles are vehicles that are steered by using handlebars to turn the front wheel. They are lightweight, agile, and fast, and are widely used in patrol, passenger and freight transportation, and other fields.

[0003] Motorcycles typically consist of a frame, body panels, running gear, suspension system, seat, electrical system, and powertrain. The powertrain includes cylinder bores and cylinder water jackets. Coolant flows through the cylinder water jackets, carrying away heat from the jacket walls and thus cooling the cylinders. In related technologies, improving cooling efficiency at a constant cost while maintaining a constant coolant supply is a pressing issue that needs to be addressed. Summary of the Invention

[0004] In order to overcome the shortcomings of the prior art, the purpose of this application is to provide a powertrain and a motorcycle using the powertrain, wherein the coolant has a high heat dissipation efficiency for the cylinder block.

[0005] To achieve the above objectives, this application adopts the following technical solution:

[0006] A powertrain includes a housing, a crankshaft, and a piston. The housing includes a crankcase and a cylinder block connected to the crankcase. The cylinder block has a cylinder bore and a cylinder water jacket, the cylinder water jacket surrounding the cylinder bore. The cylinder water jacket includes a first sidewall near the cylinder bore and a second sidewall away from the cylinder bore, with a water channel for coolant passage formed between the first and second sidewalls. The crankshaft is located within the crankcase and rotatably connected to the crankcase. The piston is at least partially located within the cylinder bore and drively connected to the crankshaft. Both the first and second sidewalls are arc-shaped and arranged around the centerline of the cylinder bore. The first sidewall protrudes radially along the cylinder bore to form a protrusion, the distance between the first and second sidewalls being greater than the distance between the first sidewall and the protrusion.

[0007] Furthermore, the water channel includes an inlet section and a cooling section. The inlet section is connected to the cooling section and is used to transport coolant to the cooling section. The cooling section surrounds the cylinder bore. The difference between the maximum and minimum values ​​of the radius of curvature of the second sidewall of the cooling section is the sidewall difference. The ratio of the sidewall difference to the average radius of curvature of the second sidewall of the cooling section ranges from 0 to 0.2. Several protrusions are provided, and the protrusions are arranged sequentially along the circumference of the first sidewall.

[0008] Furthermore, the protrusion has a raised curved surface that arches away from the first sidewall, and the ratio of the radius of curvature of the raised curved surface to the radius of curvature of the first sidewall is in the range of 0.4 to 0.6; the ratio of the radius of curvature of the raised curved surface to the width of the cooling section is in the range of 2.6 to 3.9.

[0009] Furthermore, the protrusion has a cylindrical structure along the centerline of the cylinder bore. The distance between the first sidewall and the inner wall of the cylinder bore is the first thickness, and the ratio of the first thickness to the width of the cooling section is in the range of 0.82 to 1.25. The distance between the protrusion and the inner wall of the cylinder bore is the second thickness, and the ratio of the second thickness to the width of the cooling section is in the range of 1 to 1.5.

[0010] Furthermore, the protrusion includes an upper part and a lower part arranged along the extension direction of the cylinder bore centerline, and the upper and lower parts are arranged alternately along the extension direction of the water channel.

[0011] Furthermore, along the flow direction of the coolant within the cooling section, the thickness of the multiple protrusions gradually increases radially along the cylinder bore.

[0012] Furthermore, along the circumference of the cylinder bore, the ratio of the arc length of the second sidewall between two adjacent protrusions to the arc length of the second sidewall occupied by each protrusion ranges from 0.75 to 0.96.

[0013] Furthermore, the cylinder bores are provided in multiple ways, arranged in a straight line. The water channel includes a junction section located at the junction of two adjacent cylinder bores. The distance between the inner walls of two adjacent cylinder bores is the adjacent wall thickness. The distance between the first side wall and the inner wall of the cylinder bore is the first thickness. The ratio of the adjacent wall thickness to the first thickness ranges from 0.9 to 1.1. The junction section is connected to the cooling section. The ratio of the width of the junction section to the width of the cooling section ranges from 2.1 to 3.3.

[0014] Furthermore, the chamfer angle between the second sidewall and the bottom of the waterway is greater than the chamfer angle between the first sidewall and the bottom of the waterway.

[0015] To achieve the above objectives, this application also adopts the following technical solution:

[0016] A motorcycle includes a frame, body panels, a running gear, and the aforementioned powertrain, wherein the body panels at least partially cover the frame, the running gear is at least partially located below the frame, and the powertrain is supported by the frame and drivenly connected to the running gear.

[0017] In this application, the above-mentioned arrangement can cause the coolant to form turbulence at the protrusion, which is beneficial to improving the heat exchange efficiency between the coolant and the cylinder bore. At the same time, the protrusion can also increase the heat exchange area between the cylinder and the coolant, which is beneficial to improving the heat dissipation efficiency of the coolant on the cylinder block. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the overall structure of a motorcycle provided in an embodiment of this application.

[0019] Figure 2 This is a schematic diagram of the overall structure of the powertrain provided in an embodiment of this application.

[0020] Figure 3 This is an exploded view of the powertrain provided in an embodiment of this application.

[0021] Figure 4 This is a schematic diagram of the cylinder block of the powertrain provided in an embodiment of this application.

[0022] Figure 5 This is a structural schematic diagram of the cylinder block of the powertrain provided in an embodiment of this application from another perspective.

[0023] Figure 6 Examples of embodiments of this application Figure 5 Enlarged diagram of point A in the middle. Detailed Implementation

[0024] To enable those skilled in the art to better understand the present application, the technical solutions in specific embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings.

[0025] like Figure 1 and Figure 2 As shown, this application provides a motorcycle 100, which includes a frame 11, a body panel 12, a running system 13, a suspension system 14, a seat 15, an electrical system 16, a transmission system (not shown) and a powertrain 200.

[0026] For ease of description, this application defines the directions of front, back, left, right, up, and down. The front-back direction refers to the length direction of the motorcycle frame 11, the left-right direction refers to the width direction of the motorcycle frame 11, and the up-down direction refers to the height direction of the motorcycle frame 11. In this embodiment, the directions of front, back, left, right, up, and down are based on the motorcycle 100 traveling on a level road surface, not on a sloping road surface.

[0027] The frame 11 serves as the basic framework of the motorcycle 100, supporting the body panel 12, running system 13, suspension system 14, seat 15, electrical system 16, transmission system, and powertrain 200. The body panel 12 is at least partially located on and connected to the frame 11, protecting the internal components of the motorcycle 100. The running system 13 is at least partially located below the frame 11, and the suspension system 14 connects the running system 13 to the frame 11. The powertrain 200 is supported by the frame 11. The electrical system 16 is supported by the frame 11 and is at least partially mounted on the body panel 12 or the frame 11. The electrical system 16 is used to display the motorcycle 100's driving data and control the motorcycle 100's operation. The seat 15 is supported by the frame 11 and is used to support the driver and / or passenger. The transmission system is used to transmit power to the powertrain 200. The transmission system is supported by the frame 11 and is used to drive the powertrain 200 to the running system 13.

[0028] like Figure 3 As shown, in some implementations, the powertrain 200 may be an engine supported by the frame 11. In other implementations, the powertrain 200 may be an assembly of an engine and a transmission, supported by the frame 11, with the engine and transmission mechanism connected in a transmission.

[0029] Taking the powertrain 200 as an example, the engine includes a housing 21, a crankshaft 22, an intake mechanism 23, an ignition mechanism (not shown), a timing mechanism 25, and a piston mechanism 26. The housing 21 serves as the basic frame of the engine, supporting the crankshaft 22, intake mechanism 23, ignition mechanism, timing mechanism 25, and piston mechanism 26. Specifically, the housing 21 includes a cylinder head cover 211, a cylinder head 212, a cylinder block 213, a crankcase 214, and an oil pan 215, which are connected sequentially. The cylinder head 212 and cylinder block 213 are connected to form a combustion chamber. The intake mechanism 23 is connected to the cylinder head 212 and provides air to the combustion chamber to mix air and fuel. The ignition mechanism is at least partially located within the combustion chamber and is used to ignite the air-fuel mixture. A piston mechanism 26 is at least partially located within the cylinder block 213. The piston mechanism 26 converts the thermal energy generated by the combustion of the air-fuel mixture into mechanical energy. Specifically, the piston mechanism 26 includes a piston that converts thermal energy into reciprocating mechanical energy. A crankshaft 22 is at least partially located within a crankcase 214 and is rotatably connected to the crankcase 214. The crankshaft 22 converts the reciprocating motion of the piston into rotational motion and is drive-connected to a transmission mechanism. A timing mechanism 25 is at least partially located within the cylinder head 212 and is drive-connected to the crankshaft 22. The timing mechanism 25 controls the intake and exhaust of the engine.

[0030] like Figure 4 and Figure 5 As shown, in one embodiment, the cylinder block 213 has a cylinder bore 2131 and a cylinder water jacket 2132, with the cylinder water jacket 2132 surrounding the cylinder bore 2131. A piston (not shown) is at least partially located within the cylinder bore 2131 and is drively connected to the crankshaft 22. In some embodiments, the cylinder water jacket 2132 contains coolant, thereby cooling the bore wall of the cylinder bore 2131 and components such as the piston within the cylinder bore 2131.

[0031] In this embodiment, the cylinder water jacket 2132 includes a first sidewall 2132a and a second sidewall 2132d away from the cylinder bore 2131. The first sidewall 2132a is the sidewall of the cylinder water jacket 2132 closest to the cylinder bore 2131. A water channel 2133 for coolant to flow is formed between the first sidewall 2132a and the second sidewall 2132d, through which the cylinder bore 2131 is cooled by the coolant. Note that the first sidewall 2132a and the second sidewall 2132d do not refer to wall surfaces, but rather to walls with a certain thickness.

[0032] Specifically, the first sidewall 2132a and the second sidewall 2132d are arc-shaped and arranged around the centerline of the cylinder bore 2131. The first sidewall 2132a protrudes radially along the cylinder bore 2131 to form a protrusion 2132b. The distance between the first sidewall 2132a and the second sidewall 2132d is greater than the distance between the first sidewall 2132a and the protrusion 2132b. The protrusion 2132b allows the coolant in the cylinder water jacket 2132 to form turbulence. Since the coolant temperature away from the first sidewall 2132a is lower than that near the first sidewall 2132a, the turbulent coolant can flow chaotically and disorderly at the protrusion 2132b through the above arrangement. This allows the cooler coolant away from the first sidewall 2132a to mix with the hotter coolant near the first sidewall 2132a, thereby improving the cooling efficiency of the coolant to the cylinder block 213. Secondly, the turbulence formed by the coolant in the protrusion 2132b can increase the residence time of the coolant in the protrusion 2132b, thereby improving the heat exchange effect between the coolant and the cylinder bore 2131, and thus improving the heat dissipation efficiency of the coolant on the cylinder block 213.

[0033] In addition, the protrusion 2132b can increase the contact area between the first sidewall 2132a and the coolant in the cylinder water jacket 2132.

[0034] According to the convection heat transfer formula:

[0035] Q=h*A*(T1-T2) (1)

[0036] Where Q is the heat exchanged between a unit area of ​​solid surface and fluid per unit time, also known as heat flux density; h is the surface convective heat transfer coefficient; A is the wall area; T1 is the temperature of the solid surface; and T2 is the temperature of the fluid.

[0037] As can be seen from formula (1), the heat exchange capacity can be increased by increasing the wall area. Therefore, in this application, the heat exchange area between the first sidewall 2132a and the coolant can be increased by the protrusion 2132b, thereby further improving the heat exchange effect between the coolant and the cylinder bore 2131, which in turn helps to improve the heat dissipation effect of the coolant on the cylinder bore 2131.

[0038] In one implementation, the water channel 2133 includes an inlet section 2133a and a cooling section 2133b. The inlet section 2133a communicates with the cooling section 2133b, and is used to deliver coolant to the cooling section 2133b. The cooling section 2133b surrounds the cylinder bore 2131. The difference between the maximum and minimum values ​​of the radius of curvature of the second sidewall 2132d of the cooling section 2133b is called the sidewall difference value, and the ratio of the sidewall difference value to the average radius of curvature of the second sidewall 2132d of the cooling section 2133b ranges from 0 to 0.2. Specifically, the ratio of the sidewall difference value to the average radius of curvature of the second sidewall 2132d of the cooling section 2133b is 0. This design avoids excessively large ratios that could cause coolant fluctuations at the second sidewall 2132d, ensuring that the second sidewall 2132d has a smooth, even surface, thus allowing the coolant in the water channel 2133 to flow stably at the second sidewall 2132d. Furthermore, since the second sidewall 2132d is the outer wall of the water channel 2133, the centrifugal force of the coolant exiting from the second sidewall 2132d is relatively large. Therefore, setting the shape of the second sidewall 2132d to be smooth and even avoids disturbing the coolant.

[0039] In this embodiment, a plurality of protrusions 2132b are provided, and the plurality of protrusions 2132b are arranged sequentially along the circumference of the first sidewall 2132a. This arrangement allows the coolant to form turbulence at the protrusions 2132b, which is beneficial to improving the heat dissipation effect of the coolant on the cylinder bore 2131.

[0040] It should be noted that the centrifugal force of the coolant at the first side wall 2132a can drive the coolant to flow through the protrusion 2132b to achieve the heat dissipation effect.

[0041] In one embodiment, the protrusion 2132b has a raised curved surface that arches away from the first sidewall 2132a, and the ratio of the radius of curvature of the raised curved surface to the radius of curvature of the first sidewall 2132a ranges from 0.4 to 0.6. Specifically, the ratio of the radius of curvature of the raised curved surface to the radius of curvature of the first sidewall 2132a ranges from 0.46 to 0.56. More specifically, the ratio of the radius of curvature of the raised curved surface to the radius of curvature of the first sidewall 2132a is 0.51. This configuration avoids an excessively large ratio, which would result in an excessively large curvature of the protrusion 2132b. This prevents excessive turbulence in the protrusion 2132b from interfering with the coolant flow at the second sidewall 2132d. Instead, it ensures that the turbulence at the first sidewall 2132a is assimilated with the coolant in the water channel 2133 before reaching the second sidewall 2132d, thus preventing interference with the normal flow of coolant in the water channel 2133 and facilitating coolant circulation within the water channel 2133. Furthermore, it avoids an excessively small ratio, which would result in a small curvature of the protrusion 2132b, thus preventing insufficient turbulence and improving the heat dissipation effect of the cylinder bore 2131.

[0042] In this embodiment, the ratio of the radius of curvature of the raised surface to the width of the cooling section 2133b ranges from 2.6 to 3.9. Specifically, the ratio of the radius of curvature of the raised surface to the width of the cooling section 2133b ranges from 2.9 to 3.58. More specifically, the ratio of the radius of curvature of the raised surface to the width of the cooling section 2133b is 3.26. This setting avoids the aforementioned ratio being too large, which would result in an excessively large curvature of the raised portion 2132b, thus preventing excessive turbulence of the coolant formed at the raised portion 2132b from interfering with the coolant flow at the second sidewall 2132d. This allows the turbulence formed at the first sidewall 2132a to be assimilated with the coolant in the water channel 2133 before flowing to the second sidewall 2132d, thereby preventing the turbulence formed at the first sidewall 2132a from interfering with the normal flow of coolant in the water channel 2133 and facilitating the circulation of coolant within the water channel 2133. In addition, it can also avoid the curvature of the protrusion 2132b being too small due to the above ratio being too small, thereby avoiding insufficient turbulence effect formed at the protrusion 2132b, which is conducive to improving the heat dissipation effect of the cylinder bore 2131.

[0043] like Figure 6As shown, in one embodiment, the protrusion 2132b has a cylindrical structure along the centerline of the cylinder bore 2131. The distance between the first sidewall 2132a and the inner wall of the cylinder bore 2131 is a first thickness D1, and the ratio of the first thickness D1 to the width W1 of the cooling section 2133b ranges from 0.82 to 1.25. Specifically, the ratio of the first thickness D1 to the width W1 of the cooling section 2133b ranges from 0.93 to 1.14. More specifically, the ratio of the first thickness D1 to the width W1 of the cooling section 2133b is 1.04. This configuration avoids an excessively large first thickness D1 due to the aforementioned ratio, thereby preventing a reduction in the heat exchange efficiency of the coolant through the first sidewall 2132a and the cylinder bore 2131, and thus improving the heat dissipation effect of the cylinder bore 2131. In addition, it can also avoid the first thickness D1 being too small due to the above ratio being too small, thereby avoiding the sidewall of cylinder bore 2131 being too thin, which in turn helps to improve the structural strength of cylinder bore 2131.

[0044] In this embodiment, the distance between the protrusion 2132b and the inner wall of the cylinder bore 2131 is the second thickness D2, and the ratio of the second thickness D2 to the width W2 of the cooling section 2133b ranges from 1 to 1.5. Specifically, the ratio of the second thickness D2 to the width W2 of the cooling section 2133b ranges from 1.13 to 1.39. More specifically, the ratio of the second thickness D2 to the width W2 of the cooling section 2133b is 1.26. This setting avoids the above ratio being too large, which would result in an excessively small flow cross-section of the water channel 2133 at the protrusion 2132b, thus avoiding a reduction in the flow rate of coolant at the protrusion 2132b and consequently a decrease in the heat exchange effect of the coolant. Furthermore, it also avoids the above ratio being too small, which would result in an excessively large flow cross-section of the water channel 2133 at the protrusion 2132b, thus avoiding insufficient turbulence effect of the coolant at the protrusion 2132b, thereby improving the heat dissipation effect of the cylinder bore 2131.

[0045] In one embodiment, the protrusion 2132b includes an upper portion (not shown) and a lower portion (not shown) arranged along the extension direction of the cylinder bore 2131 centerline, with the upper and lower portions staggered along the extension direction of the water channel 2133. This staggered arrangement of the upper and lower portions increases the number of turbulent regions formed within the water channel 2133, allowing the coolant to remain within the water channel 2133 for a longer period. This improves the heat exchange effect between the coolant and the cylinder bore 2131, thereby enhancing the heat dissipation effect of the cylinder bore 2131.

[0046] In one implementation, along the flow direction of the coolant within the cooling section 2133b, the thickness of multiple protrusions 2132b gradually increases radially along the cylinder bore 2131. This arrangement, by increasing the thickness of the protrusions 2132b radially along the cylinder bore 2131, enhances the turbulence effect of the coolant at the protrusions 2132b, thereby improving the heat dissipation effect of the coolant on the cylinder bore 2131 at the protrusions 2132b. Understandably, when the coolant flows within the cooling section 2133b, its temperature increases after heat exchange, leading to a decrease in its heat dissipation effect. Therefore, by enhancing the turbulence effect at the protrusions 2132b, even with an increased coolant temperature, the coolant can meet the heat dissipation requirements of the cylinder bore 2131, thus improving the overall heat exchange uniformity of the cylinder bore 2131.

[0047] In one embodiment, along the circumferential direction of the cylinder bore 2131, the ratio of the arc length of the second sidewall 2132d between two adjacent protrusions 2132b to the arc length of the second sidewall 2132d occupied by each protrusion 2132b ranges from 0.75 to 0.96. Specifically, the ratio of the arc length of the second sidewall 2132d between two adjacent protrusions 2132b to the arc length of the second sidewall 2132d occupied by each protrusion 2132b ranges from 0.79 to 0.92. More specifically, the ratio of the arc length of the second sidewall 2132d between two adjacent protrusions 2132b to the arc length of the second sidewall 2132d occupied by each protrusion 2132b is 0.84. This configuration avoids the situation where the ratio is too small, resulting in an excessively small gap between two adjacent protrusions 2132b. This prevents the first sidewall 2132a from becoming too flat, thus preventing the protrusions 2132b from failing to generate turbulence and improving the cooling effect of the coolant on the cylinder bore 2131. Furthermore, it also avoids the situation where the ratio is too large, resulting in an excessively large gap between two adjacent protrusions 2132b. This prevents the excessive gap from causing insufficient turbulence within the water channel 2133, thus minimizing the turbulent effect of the coolant and further improving the cooling effect of the coolant on the cylinder bore 2131.

[0048] like Figure 5As shown, in one embodiment, multiple cylinder bores 2131 are provided, arranged in a straight line. The water channel 2133 includes a boundary section 2133c located at the junction of two adjacent cylinder bores 2131. The distance between the inner walls of two adjacent cylinder bores 2131 is the adjacent wall thickness D3, and the distance between the first side wall 2132a and the inner wall of the cylinder bore 2131 is the first thickness D1. The ratio of the adjacent wall thickness D3 to the first thickness D1 ranges from 0.9 to 1.1. Specifically, the ratio of the adjacent wall thickness D3 to the first thickness D1 ranges from 0.95 to 1.05. More specifically, the ratio of the adjacent wall thickness D3 to the first thickness D1 is 1. This setting avoids the above ratio being too large, which would result in an excessively large adjacent wall thickness D3, thus preventing the heat dissipation effect of the cylinder bore 2131 at the adjacent wall thickness D3 from being too low and reducing the overall heat dissipation effect of the cylinder bore 2131, thereby improving the cooling effect of the cylinder bore 2131. In addition, it can also avoid the above ratio being too small, which would result in the adjacent wall thickness D3 being too thin, thereby avoiding the structural strength of the cylinder bore 2131 at the adjacent wall thickness D3 being too low, so as to improve the overall structural strength of the cylinder bore 2131.

[0049] In one implementation, the junction section 2133c is connected to the cooling section 2133b, and the ratio of the width of the junction section 2133c to the width of the cooling section 2133b ranges from 2.1 to 3.3. Specifically, the ratio of the width of the junction section 2133c to the width of the cooling section 2133b ranges from 2.4 to 3. More specifically, the ratio of the width of the junction section 2133c to the width of the cooling section 2133b is 2.7. With this configuration, the junction section 2133c has a larger volume than the cooling section 2133b, which allows the coolant introduced into the water inlet section 2133a to be buffered within the junction section 2133c. This prevents the coolant from flowing too fast within the water channel 2133, thus reducing the heat exchange effect of the coolant and improving the heat dissipation effect on the cylinder bore 2131. Simultaneously, the cooling within the water channel 2133 reduces the flow rate at the junction section 2133c, which helps balance the overall pressure of the coolant within the water channel 2133. Secondly, it avoids the aforementioned ratio being too small, resulting in an excessively small volume at the junction section 2133c, thus preventing the junction section 2133c from failing to buffer and reduce the coolant flow rate, thereby improving the cooling effect of the coolant on the cylinder bore 2131. Furthermore, it also avoids the aforementioned ratio being too large, resulting in an excessively large volume at the junction section 2133c, thus preventing the coolant flow rate at the junction section 2133c from being too low, which would reduce the heat exchange effect of the coolant and further improve the cooling effect on the cylinder bore 2131.

[0050] In one implementation, the chamfer angle η1 between the second sidewall 2132d and the bottom of the water channel 2133 is greater than the chamfer angle η2 between the first sidewall 2132a and the bottom of the water channel 2133. This arrangement allows the coolant to flow more smoothly at the chamfer angle η1 of the second sidewall 2132d compared to the chamfer angle η2 of the first sidewall 2132a, facilitating stable flow of the coolant on the second sidewall 2132d. Simultaneously, it also helps to increase the flow velocity of the coolant at the chamfer angle η2 of the first sidewall 2132a, promoting turbulence at the protrusion 2132b of the first sidewall 2132a, thereby improving the cooling effect of the cylinder bore 2131.

[0051] It should be understood that those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A powertrain, comprising: The housing includes a crankcase and a cylinder block connected to the crankcase. The cylinder block has a cylinder bore and a cylinder water jacket. The cylinder water jacket is arranged around the cylinder bore. The cylinder water jacket includes a first sidewall close to the cylinder bore and a second sidewall away from the cylinder bore. A water channel for coolant to pass through is formed between the first sidewall and the second sidewall. A crankshaft located within the crankcase and rotatably connected to the crankcase; A piston, which is at least partially located within the cylinder bore and is drively connected to the crankshaft; Its features are, Both the first sidewall and the second sidewall are arc-shaped and arranged around the center line of the cylinder bore; the first sidewall protrudes radially along the cylinder bore to form a protrusion, and the distance between the first sidewall and the second sidewall is greater than the distance between the first sidewall and the protrusion.

2. The powertrain according to claim 1, characterized in that, The water channel includes an inlet section and a cooling section. The inlet section is connected to the cooling section and is used to deliver coolant to the cooling section. The cooling section surrounds the cylinder bore. The difference between the maximum and minimum values ​​of the radius of curvature of the second sidewall of the cooling section is the sidewall difference value. The ratio of the sidewall difference value to the average radius of curvature of the second sidewall of the cooling section ranges from 0 to 0.

2. A plurality of protrusions are provided, and the plurality of protrusions are arranged sequentially along the circumference of the first sidewall.

3. The powertrain according to claim 2, characterized in that, The protrusion has a raised curved surface that arches away from the first sidewall, and the ratio of the radius of curvature of the raised curved surface to the radius of curvature of the first sidewall is in the range of 0.4 to 0.6; the ratio of the radius of curvature of the raised curved surface to the width of the cooling section is in the range of 2.6 to 3.

9.

4. The powertrain according to claim 2, characterized in that, The protrusion has a cylindrical structure along the centerline of the cylinder bore. The distance between the first sidewall and the inner wall of the cylinder bore is the first thickness. The ratio of the first thickness to the width of the cooling section is in the range of 0.82 to 1.

25. The distance between the protrusion and the inner wall of the cylinder bore is the second thickness. The ratio of the second thickness to the width of the cooling section is in the range of 1 to 1.

5.

5. The powertrain according to claim 2, characterized in that, The protrusion includes an upper part and a lower part arranged along the extension direction of the cylinder bore centerline, and the upper part and the lower part are arranged alternately along the extension direction of the water channel.

6. The powertrain according to claim 2, characterized in that, Along the flow direction of the coolant within the cooling section, the thickness of the plurality of protrusions gradually increases along the radial direction of the cylinder bore.

7. The powertrain according to claim 2, characterized in that, Along the circumference of the cylinder bore, the ratio of the arc length of the second sidewall between two adjacent protrusions to the arc length of the second sidewall occupied by each protrusion ranges from 0.75 to 0.

96.

8. The powertrain according to claim 2, characterized in that, The cylinder bore is provided in multiple ways, and the multiple cylinder bores are arranged in a straight line. The water channel includes a junction section located at the junction of two adjacent cylinder bores. The distance between the inner walls of two adjacent cylinder bores is the adjacent wall thickness. The distance between the first side wall and the inner wall of the cylinder bore is the first thickness. The ratio of the adjacent wall thickness to the first thickness ranges from 0.9 to 1.

1. The junction section is connected to the cooling section, and the ratio of the width of the junction section to the width of the cooling section is in the range of 2.1 to 3.

3.

9. The powertrain according to claim 1, characterized in that, The chamfer angle between the second sidewall and the bottom of the waterway is greater than the chamfer angle between the first sidewall and the bottom of the waterway.

10. A motorcycle, characterized in that, include: Frame; A body panel that at least partially covers the vehicle frame; A walking system, at least partially located below the vehicle frame; The powertrain as described in any one of claims 1 to 9, wherein the powertrain is supported by the vehicle frame and is drive-connected to the running gear system.

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