Cooling structure of motorcycle engine

Abstract

The present invention provides a cooling structure for a motorcycle engine, belonging to the field of engine technology. It solves the problem of poor engine oil cooling performance in existing motorcycle engines. The cooling structure of the motorcycle engine comprises a housing, a cylinder block, and a cylinder head. An oil cooler is mounted on the outer wall of the housing, and a thermostat is mounted on the outer wall of the cylinder block. The cooling structure includes heat dissipation ribs on the front side wall of the housing. The heat dissipation ribs protrude forward, one of the heat dissipation ribs defines a water inlet channel, and the other defines a water outlet channel. The upper end of the water inlet channel is connected to the upper water jacket, and the lower end is connected to the water inlet of the oil cooler. The upper end of the water outlet channel is connected to the thermostat, and the lower end is connected to the water outlet of the oil cooler. The cooling structure of the motorcycle engine has an excellent cooling effect on engine oil.

Description

Technical Field

[0001] The invention belongs to the technical field of engines and relates to a cooling structure of a motorcycle engine. Background Art

[0002] A motorcycle engine ignites the fuel mixture entering the cylinder, converting the resulting heat into mechanical energy. The crankshaft then transmits this energy through a transmission mechanism to the motorcycle's rear wheel, effectively turning it into propulsion. The eight main components of a motorcycle engine, arranged from top to bottom, are the cylinder head, cylinder block, and engine case. The cylinder head houses components like spark plugs and valves, the cylinder block houses the combustion chamber, and the case houses the crankshaft. The piston in the combustion chamber drives the crankshaft below via a connecting rod, which then connects the crankshaft's outer end to the rear wheel via a transmission mechanism, generating power output. Because the engine's temperature is low upon startup, affecting performance, it needs to be heated up. During normal operation, a significant amount of heat is generated, requiring cooling. This requires a circulating water circuit. An upper water jacket is located within the cylinder head, a chamber used to cool the cylinder head, spark plugs, and other components. A lower water jacket surrounds the combustion chamber and cools the cylinder block. The engine has two circulating water circuits: a small circuit and a large circuit. The thermostat switches these two circuits via an internal valve. The small circuit runs from water pump to upper water jacket, thermostat, lower water jacket, and water pump. This entire cycle is unheated, allowing heat to be circulated and transported, ensuring rapid and even engine temperature rise upon startup. The large circuit runs from water pump to upper water jacket, thermostat, radiator, thermostat, lower water jacket, and water pump. Cooling water is dissipated through the radiator and used to cool the engine.

[0003] The engine also has engine oil for lubrication, that is, the oil pump draws the oil in the oil pan into the oil channel. The oil in the oil channel is filtered by the oil filter and then lubricated to the crankshaft, camshaft and other components. However, the oil temperature will rise during operation, so an oil cooler will be installed on the engine. The oil cooler is an existing heat exchange device with water and oil circuits inside. Therefore, it has an oil inlet, an oil outlet, a water inlet and a water outlet. The water inlet and the water outlet are respectively connected to the circulating water circuit, and the oil inlet and the oil outlet are respectively connected to the oil channel, and the engine oil is cooled by cooling water.

[0004] As disclosed in the patent application (application number: 202211647623.9), the water circulation structure of a motorcycle engine includes a cylinder block and a cylinder head. The water circulation structure includes a water pump, a thermostat, and a water circuit. The water circuit includes a cylinder water jacket located in the cylinder block and a cylinder head water jacket located in the cylinder head. The inlet and outlet of the water pump are respectively connected to the cylinder water jacket and the cylinder head water jacket. The water circulation structure also includes a thermostat located on one side of the engine. The thermostat has an inlet chamber and an outlet chamber. The inlet chamber and the outlet chamber are connected through a liquid port. The cylinder water jacket is connected to the inlet chamber, and the cylinder head water jacket is connected to the outlet chamber. The inner wall of the inlet chamber has an inlet, and the inner wall of the outlet chamber has an outlet. At the same time, the engine also includes an oil cooler. The inner wall of the inlet chamber has a port 1, and the inner wall of the outlet chamber has a port 2. Port 1 and port 2 are respectively connected to the outlet and inlet of the oil cooler through external water pipes to cool the engine oil. However, the liquid outlet cavity that supplies water to the oil cooler is connected to the cylinder head water jacket, that is, the water pump inputs cooling water into the cylinder head water jacket to cool the cylinder head, and the cooling water in the cylinder head water jacket then enters the liquid outlet cavity, and then enters the oil cooler to cool the engine oil. The cooling water after cooling the cylinder head has a higher temperature. At this time, it directly enters the oil cooler to cool the engine oil, and the cooling effect is poor. Summary of the Invention

[0005] The purpose of the present invention is to solve the above problems in the existing technology and propose a cooling structure for a motorcycle engine to solve the problem that the existing motorcycle engine has a poor cooling effect on the engine oil.

[0006] The objectives of the present invention can be achieved through the following technical solutions: a cooling structure for a motorcycle engine, the engine comprising a case, a cylinder block and a cylinder head with an upper water jacket, an oil cooler being mounted on the outer wall of the case, and a thermostat being mounted on the outer wall of the cylinder block, characterized in that the cooling structure comprises two heat dissipation ribs integrally formed on the front side wall of the case, the heat dissipation ribs being long strips and protruding forward, a water inlet channel being provided in one of the heat dissipation ribs along its length, and a water outlet channel being provided in the other heat dissipation rib along its length, the upper end of the water inlet channel being connected to the upper water jacket, and the lower end being connected to the water inlet of the oil cooler, the upper end of the water outlet channel being connected to the thermostat, and the lower end being connected to the water outlet of the oil cooler.

[0007] From bottom to top, the engine consists of an oil pan, a casing, a cylinder block, and a cylinder head. The casing houses the crankshaft, and the cylinder block contains a combustion chamber. The piston in the combustion chamber drives the crankshaft below via a connecting rod to generate power. The upper water jacket is a chamber within the cylinder head used to cool the cylinder head, spark plugs, and other components. The engine has two circulating water circuits: a small loop and a large loop. The thermostat switches between the two circuits. The small loop, which runs from water pump to upper water jacket, thermostat, cylinder block, and water pump, is used to quickly heat up the engine during startup. The large loop, which typically runs from water pump to upper water jacket, thermostat, radiator, thermostat, cylinder block, and water pump, is used to cool the engine. The oil cooler is an existing heat exchange device with internal water and oil circuits, and therefore has an oil inlet, an oil outlet, a water inlet, and a water outlet. Cooling water is used to cool the engine oil. The present application connects the water circuit of the oil cooler to the circulating water circuit, that is, the cooling water in the upper water jacket enters the oil cooler through the water inlet channel to cool the engine oil, then returns to the thermostat from the water outlet channel, and then flows into the cylinder body from the thermostat. Since the cooling water in the upper water jacket has exchanged heat with the cylinder head, the water temperature rises. For this reason, the present application provides protruding heat dissipation ribs on the side walls of the box body. The two are integrally formed so that their material is consistent with the material of the box body, both of which are metal materials with good thermal conductivity. The heat dissipation ribs are located on the front side wall and set forward, and the water inlet channel is opened in the heat dissipation ribs. When the motorcycle is running, the airflow acts on the heat dissipation ribs from the front, dissipates heat from the heat dissipation ribs, and reduces the temperature of the cooling water in the water inlet channel, so that the cooling water after cooling the cylinder head can be cooled first, and then enters the oil cooler to cool the engine oil, thereby improving the cooling effect of the engine oil. At the same time, the water outlet channel is also opened in another heat dissipation rib, that is, the cooling water after heat exchange with the engine oil in the oil cooler can also be cooled down when passing through the water outlet channel, so that the cooling water enters the thermostat at a lower temperature, and will not affect the cooling of the cylinder block due to the cooling of the engine oil, thereby improving the cooling effect of the entire large circulation water circuit.

[0008] In the above-mentioned motorcycle engine cooling structure, the upper end of the front side wall of the housing is tilted forward, so that the upper ends of the two heat dissipation ribs are tilted forward. The lower portion of the front side wall of the housing has an oil cooling mount that protrudes forward. The oil cooler is fixedly mounted on the front end surface of the oil cooling mount. The oil cooling mount is located below the two heat dissipation ribs, and the lower ends of the two heat dissipation ribs extend downward to the upper side surface of the oil cooling mount. The upper portions of the front side wall of the housing and the heat dissipation ribs are both tilted forward, so that the lower oil cooler is positioned rearward. While airflow acts on the heat dissipation ribs to dissipate heat, it can also be directed from top to bottom, acting on the lower oil cooling mount and oil cooler. This allows the airflow to cool the cooling water while also directly cooling the oil cooler, thereby improving the cooling effect on the engine oil.

[0009] In the aforementioned motorcycle engine cooling structure, a long, strip-shaped guide groove is formed between the two heat dissipation ribs. The upper end of the guide groove is tilted forward, and the lower end extends to the upper side of the oil cooler mounting base. Airflow is concentrated within the guide groove, avoiding direct diffusion from the left and right sides. Airflow flows downward along the guide groove, improving the cooling effect on the heat dissipation ribs on both sides. At the same time, the airflow within the guide groove directly impacts the oil cooler mounting base below, improving the heat dissipation effect on the oil cooler mounting base. This also allows the oil cooler mounted on the oil cooler mounting base to dissipate heat and cool down, improving the cooling effect on the engine oil.

[0010] In the aforementioned motorcycle engine cooling structure, the oil cooler is rectangular and located below two heat dissipation ribs. The angle between the upper side of the oil cooler and the heat dissipation ribs is acute. The upper side of the oil cooler is generally horizontal, while the upper ends of the heat dissipation ribs are tilted forward. This angle ensures that airflow from the front sidewall of the housing and within the guide grooves is fully applied to the upper side of the oil cooler, enhancing the cooling effect on the oil cooler and, consequently, the engine oil.

[0011] In the aforementioned motorcycle engine cooling structure, the thermostat includes a housing mounted on the front sidewall of the cylinder block. A water inlet chamber and a water return chamber are formed between the housing and the cylinder block. The water inlet chamber communicates with the upper water jacket. The upper end of the water inlet channel communicates with the water inlet chamber, and the upper end of the water outlet channel communicates with the water return chamber. Since the cylinder block is located between the cylinder head and the casing, the water inlet channel communicates with the upper water jacket via the water inlet chamber, eliminating the need for additional water channels and simplifying the structure.

[0012] In the cooling structure of the above-mentioned motorcycle engine, the shell also has a return water chamber and a water outlet chamber, the return water chamber has a return water interface for connecting to the water outlet end of the radiator, and the water outlet chamber has a water outlet interface for connecting to the water inlet end of the radiator. The cylinder body is provided with a lower water jacket, the return water chamber is connected to the lower water jacket, the water inlet chamber is connected to the water outlet chamber, and the return water chamber and the water outlet chamber are connected through a water outlet. The shell is also provided with a valve core that can control the opening and closing of the water outlet and the water outlet interface. The output end of the water pump is connected to the upper water jacket of the cylinder head, the input end is connected to the lower water jacket of the cylinder body, the water inlet end of the radiator is connected to the water outlet interface of the water outlet chamber, and the water outlet end is connected to the return water interface of the return water chamber. Therefore, when the valve core opens the water outlet and closes the water outlet interface, a small circulation water path is formed: water pump-upper water jacket-water inlet chamber-water outlet chamber-return water chamber-lower water jacket-water pump; when the valve core closes the water outlet and opens the water outlet interface, a large circulation water path is formed: water pump-upper water jacket-water inlet chamber-water outlet chamber-radiator-return water chamber-lower water jacket-water pump. Therefore, the cooling water returning to the return water chamber through the oil cooler will not pass through the radiator for heat dissipation and cooling, but the cooling water coming out of the oil cooler can be cooled through the water outlet channel in the heat dissipation rib, thereby reducing the temperature of the cooling water in the return water chamber, avoiding affecting the cooling of the cylinder body due to cooling of the engine oil.

[0013] In the aforementioned motorcycle engine cooling structure, a heat exchange channel and a water return channel are vertically defined within the cylinder body. The lower end of the heat exchange channel communicates with the upper end of the water inlet channel, while the upper end of the heat exchange channel communicates with the water inlet chamber. The lower end of the water return channel is in contact with and communicates with the upper end of the water outlet channel, while the upper end of the water return channel communicates with the water return chamber. The heat exchange channel and water return channel are defined within the cylinder body, allowing for airflow cooling, thereby enhancing cooling effectiveness.

[0014] In the aforementioned motorcycle engine cooling structure, a buffer chamber is further defined within the cylinder body. This buffer chamber is located between the heat exchange channel and the water inlet channel. The lower end of the heat exchange channel extends downward to the top surface of the buffer chamber, while the upper end of the water inlet channel extends downward to the bottom surface of the buffer chamber. Cooling water flowing from the heat exchange channel to the water inlet channel is first buffered in the buffer chamber, thereby reducing the flow rate upon entering the water inlet channel, extending the cooling time, and improving the cooling effect.

[0015] In the aforementioned motorcycle engine cooling structure, the water inlet chamber is located above the return water chamber. The return water chamber includes a columnar, vertically disposed heat exchange portion, and the heat exchange channel extends vertically within the heat exchange portion. Since the cooling water in the water inlet chamber flows in from the upper water jacket and has already undergone heat exchange with the cylinder head, its temperature is relatively high, while the cooling water in the return water chamber enters from the radiator and has already been cooled by heat dissipation, its temperature is relatively low. Therefore, the thermostat positions the water inlet chamber above the return water chamber, requiring the heat exchange channel to pass through the return water chamber. Therefore, a columnar heat exchange portion is provided within the return water chamber, and the heat exchange channel is provided within the heat exchange portion. The cooling water in the water inlet chamber is cooled by the cooling water in the return water chamber as it flows through the heat exchange channel to the oil cooler. The cooling water then enters the water inlet channel from the heat exchange channel, receiving air cooling. This combines water cooling with air cooling, improving the cooling effect on the engine oil.

[0016] In the aforementioned motorcycle engine cooling structure, the cylinder sidewall has two through-holes connecting the lower water jacket and the return water chamber. The heat exchange portion is located approximately in the middle of the return water chamber's width and protrudes forward, with the two through-holes located on either side of the heat exchange portion. These two through-holes, located on either side of the heat exchange portion, function to divert cooling water, allowing the cooling water to fully impact and act on the heat exchange portion, thereby cooling the heat exchange portion, specifically, the cooling water within the heat exchange channel, and improving the cooling effect on the engine oil.

[0017] Compared with the prior art, the cooling structure of the motorcycle engine has the following advantages:

[0018] 1. Since protruding heat dissipation ribs are provided on the front side wall of the box body, and the water inlet channel is opened in the heat dissipation ribs, the airflow acts on the heat dissipation ribs positively when the motorcycle is running, dissipating the heat from the ribs and reducing the temperature of the cooling water in the water inlet channel. As a result, the cooling water after cooling the cylinder head can be cooled down first, and then enter the oil cooler to cool down the engine oil, thereby improving the cooling effect of the engine oil.

[0019] 2. Since the water outlet channel is opened in the heat dissipation rib, the cooling water after heat exchange with the engine oil in the oil cooler can also be cooled down when passing through the water outlet channel, so that the cooling water enters the thermostat at a lower temperature, and will not affect the cooling of the cylinder block due to the cooling of the engine oil, thereby improving the cooling effect of the entire large circulation water circuit.

[0020] 3. Since a guide groove is formed between the two heat dissipation ribs, the air flow can be gathered in the guide groove to avoid direct diffusion from the left and right sides. The air flow flows downward along the guide groove, improving the cooling effect on the heat dissipation ribs on both sides. At the same time, the air flow in the guide groove directly impacts the oil cooling mounting seat below, improving the heat dissipation effect of the oil cooling mounting seat, that is, improving the cooling effect of the engine oil.

[0021] 4. Since there is a heat exchange part in the return water chamber and the heat exchange channel is opened in the heat exchange part, the cooling water in the water inlet chamber can be cooled by the cooling water in the return water chamber when it flows to the oil cooler through the heat exchange channel, and then enters the water inlet channel from the heat exchange channel to be cooled by the air flow, thereby combining water cooling and air cooling to improve the cooling effect of the engine oil. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the three-dimensional structure of a motorcycle engine.

[0023] Figure 2 This is a three-dimensional structural diagram of a motorcycle engine from another perspective.

[0024] Figure 3 This is a front view of the structure of a motorcycle engine.

[0025] Figure 4 It is a schematic diagram of the three-dimensional structure of the cylinder.

[0026] Figure 5 yes Figure 1 A magnified view of the structure at point A.

[0027] Figure 6 yes Figure 3 Cross-sectional view of the local structure at BB in the middle.

[0028] Figure 7 yes Figure 3 Structural cross-section view at CC in the middle.

[0029] Figure 8 yes Figure 3 Structural cross-section view at DD in the middle.

[0030] Figure 9 yes Figure 3 Structural cross-section view at EE.

[0031] Figure 10 yes Figure 3 Structural cross-sectional view at FF in the middle.

[0032] Figure 11 yes Figure 10 Enlarged view of the structure at G in the middle.

[0033] Figure 12 yes Figure 3 Cross-sectional view of the local structure at HH in the middle.

[0034] Figure 13 yes Figure 3 Partial structural cross-sectional view at point II.

[0035] In the figure, 1. casing; 11. heat dissipation rib; 12. water inlet channel; 13. water outlet channel; 14. guide groove; 15. oil cooling mounting seat; 16. oil filter mounting seat; 17. air passage; 18. heat dissipation rib; 19. oil inlet channel; 2. cylinder block; 21. lower water jacket; 22. heat exchange part; 23. heat exchange channel; 24. buffer chamber; 25. return water channel; 26. through-hole; 3. cylinder head; 31. upper water jacket; 4. thermostat; 41. casing; 42. water inlet chamber; 43. return water chamber; 431. return water interface; 44. water outlet chamber; 441. water outlet interface; 45. water outlet; 46. valve core; 47. throttling part; 48. throttling channel; 5. oil cooler; 6. oil filter; 7. water pump; 71. water pipe. DETAILED DESCRIPTION

[0036] The following are specific embodiments of the present invention and the accompanying drawings to further describe the technical solutions of the present invention, but the present invention is not limited to these embodiments.

[0037] like Figure 1 、 Figure 2 As shown, a cooling structure of a motorcycle engine, the engine includes a housing 1, a cylinder block 2 and a cylinder head 3. The cylinder block 2 is fixed on the top surface of the housing 1, and the cylinder head 3 is fixed on the top surface of the cylinder block 2, and the cylinder head 3 is tilted forward. The cooling structure includes a thermostat 4 installed on the front side wall of the cylinder block 2, and an oil cooler 5 and an oil filter 6 are installed on the front side wall of the housing 1. The oil cooler 5 is located below the thermostat 4, and the oil filter 6 is located on one side of the oil cooler 5. A water pump 7 is installed on the side of the housing 1, and the output and input ends of the water pump 7 are both connected to a water pipe 71. Combined Figure 3 、 Figure 4As shown, the cylinder head 3 has an upper water jacket 31 for cooling the cylinder head 3, spark plugs, etc. The cylinder body 2 has a lower water jacket 21, which surrounds the combustion chamber and is used to cool the cylinder body 2. A water pipe 71 at the output end of the water pump 7 is connected to the upper water jacket 31 in the cylinder head 3, and a water pipe 71 at the input end of the water pump 7 is connected to the lower water jacket 21 in the cylinder body 2. The thermostat 4 includes a housing 41, which is fixedly covered on the front side wall of the cylinder body 2, and a water inlet chamber 42 and a water return chamber 43 are formed between the housing 41 and the front side wall of the cylinder body 2. A water outlet chamber 44 is also provided in the housing 41, wherein the water inlet chamber 42 is respectively connected to the upper water jacket 31 of the cylinder head 3 and the water outlet chamber 44, and one lateral end of the water outlet chamber 44 is connected to the water return chamber 43 through a water port 45. The other lateral end of the water outlet chamber 44 has a water outlet interface 441, which is used to connect to the water inlet end of the radiator, and the water return chamber 43 has a water return interface 431, which is used to connect to the water outlet end of the radiator. The return water chamber 43 is also connected to the lower water jacket 21 of the cylinder body 2. A valve core 46 capable of controlling the opening and closing of the water port 45 and the water outlet interface 441 is provided in the water outlet chamber 44 of the shell 41. The control structure of the valve core 46 is the existing technology, including an elastic member and a thermostat. When the engine is just started and the overall temperature is low, the elastic member acts on one end of the valve core 46 to close the water outlet interface 441 of the water outlet chamber 44, and the other end to open the water port 45. At this time, the circulating water circuit is a small circulating water circuit: water pump 7-upper water jacket 31-water inlet chamber 42-water outlet chamber 44-return water chamber 43-lower water jacket 21-water pump 7, which is used to quickly heat up the engine when it starts. When the engine temperature reaches the set value, the valve core 46 moves to open the water outlet interface 441 and close the water outlet 45. At this time, the circulating water circuit is a large circulating water circuit: water pump 7-upper water jacket 31-water inlet chamber 42-water outlet chamber 44-radiator-return water chamber 43-lower water jacket 21-water pump 7, which is used to cool the engine.

[0038] Specifically, combined Figures 5 to 9As shown, the oil cooler 5 is a conventional heat exchange device with internal water and oil circuits, and thus has an oil inlet, an oil outlet, a water inlet, and a water outlet, and cools the engine oil with cooling water. The front side wall of the casing 1 has a forward-projecting oil cooler mounting seat 15 and an oil filter mounting seat 16. The oil cooler 5 is fixedly mounted on the front end surface of the oil cooler mounting seat 15, and the oil filter 6 is fixedly mounted on the front end surface of the oil filter mounting seat 16. Two heat dissipation ribs 11 are integrally formed on the front side wall of the casing 1. These two heat dissipation ribs 11 are elongated and protrude forward. One heat dissipation rib 11 has a water inlet channel 12 formed along its length, and the other heat dissipation rib 11 has a water outlet channel 13 formed along its length. A heat exchange channel 23, a buffer chamber 24, and a return water channel 25 are vertically formed in the cylinder body 2. The cross-section of the buffer chamber 24 is larger than the cross-sectional area of ​​the heat exchange channel 23 and the water inlet channel 12. The upper end of the heat exchange channel 23 is connected to the water inlet chamber 42, and the lower end of the heat exchange channel 23 extends downward to the top surface of the buffer chamber 24 and is connected to the buffer chamber 24. The upper end of the water inlet channel 12 extends to the bottom surface of the buffer chamber 24 and is connected to the buffer chamber 24. The lower end of the water inlet channel 12 extends to the oil cooling mounting seat 15 and is connected to the water inlet of the oil cooler 5. The lower end of the water outlet channel 13 extends to the oil cooling mounting seat 15 and is connected to the water outlet of the oil cooler 5. The upper end of the water outlet channel 13 is connected to the lower end of the water return channel 25, and the upper end of the water return channel 25 extends to the bottom surface of the water return chamber 43 and is connected to the water return chamber 43.

[0039] The upper end of the front side wall of the box body 1 is tilted forward, so that the upper ends of the two heat dissipation ribs 11 are tilted forward, the oil cooling mounting seat 15 is located below the two heat dissipation ribs 11, and the lower ends of the two heat dissipation ribs 11 extend downward to the upper side of the oil cooling mounting seat 15. A long strip of guide groove 14 is formed between the two heat dissipation ribs 11, the upper end of the guide groove 14 is tilted forward, and the lower end extends to the upper side of the oil cooling mounting seat 15. The oil cooler 5 is in the shape of a rectangular block, and the oil cooler 5 is located below the two heat dissipation ribs 11. The angle between the upper side of the oil cooler 5 and the heat dissipation ribs 11 is an acute angle. Combined with Figure 12 、 Figure 13 As shown, the oil cooling mounting seat 15 and the oil filter mounting seat 16 are arranged horizontally and close to each other, and an air passage 17 is formed between the oil cooling mounting seat 15 and the oil filter mounting seat 16. The air passage 17 is arranged vertically, and the middle part of the air passage 17 is curved toward the side where the oil cooling mounting seat 15 is located. A heat dissipation protrusion 18 protruding forward is provided on the front side wall of the box body 1. The heat dissipation protrusion 18 passes through the air passage 17 horizontally, and an oil inlet passage 19 is opened horizontally in the heat dissipation protrusion 18. One end of the oil inlet passage 19 is connected to the oil filter 6, and the other end passes through the oil cooling mounting seat 15 and is connected to the oil inlet of the oil cooler 5. The airflow passing through the air passage 17 can cool the heat dissipation protrusion 18, thereby cooling the oil in the oil inlet passage 19.

[0040] Combine Figure 10 、 Figure 11 As shown, the water inlet chamber 42 is located above the return water chamber 43, and the return water chamber 43 has a heat exchange portion 22 extending from the bottom surface to the top surface. The heat exchange portion 22 is columnar, and the upper end of the heat exchange channel 23 is opened in the heat exchange portion 22 along the length direction, and the upper end of the heat exchange channel 23 penetrates upward to the bottom surface of the water inlet chamber 42. There are two through-holes 26 on the side wall of the cylinder body 2 that connect the lower water jacket 21 and the return water chamber 43. The heat exchange portion 22 is roughly located in the middle of the return water chamber 43 in the horizontal direction and protrudes forward. The two through-holes 26 are respectively located on both sides of the heat exchange portion 22, and the inner end of the return water interface 431 of the return water chamber 43 is tilted backward and toward the heat exchange portion 22. The bottom surface of the return water chamber 43 also has a throttling portion 47 protruding toward the heat exchange portion 22, and the throttling portion 47 extends forward to the front side wall of the return water chamber 43. The throttling portion 47 is located in the front side of the heat exchange portion 22, and a throttling channel 48 is formed between the throttling portion 47 and the heat exchange portion 22. One of the through-ports 26 and the return water interface 431 are respectively located at the two ends of the throttling channel 48. The cooling water in the return water chamber 43 needs to pass through the throttling channel 48 when entering the through-port 26 on the side. The throttling channel 48 can make the passing water flow closer to the heat exchange portion 22 and the flow rate become faster, thereby improving the cooling effect on the heat exchange portion 22.

[0041] The specific embodiments described herein are merely illustrative of the spirit of the present invention. Persons skilled in the art may make various modifications, additions, or substitutions to the described specific embodiments without departing from the spirit of the present invention or exceeding the scope of the appended claims.

[0042] Although this document frequently uses terms such as housing 1, heat dissipation ribs 11, and water inlet channel 12, the use of other terms is not excluded. These terms are used solely to more conveniently describe and explain the essence of the present invention; interpreting them as any additional limitations is contrary to the spirit of the present invention.

Claims

1. A cooling structure for a motorcycle engine, the engine comprising a housing (1), a cylinder block (2) and a cylinder head (3) having an upper water jacket (31), an oil cooler (5) being mounted on the outer wall of the housing (1), and a thermostat (4) being mounted on the outer wall of the cylinder block (2), characterized in that: The cooling structure comprises two heat dissipation ribs (11) integrally formed on the front side wall of the box body (1), the heat dissipation ribs (11) are long and protrude forward, one of the heat dissipation ribs (11) is provided with a water inlet channel (12) along the length direction, and the other heat dissipation rib (11) is provided with a water outlet channel (13) along the length direction, the upper end of the water inlet channel (12) is connected to the upper water jacket (31), and the lower end is connected to the water inlet of the oil cooler (5), the upper end of the water outlet channel (13) is connected to the thermostat (4), and the lower end is connected to the water outlet of the oil cooler (5); the thermostat The thermostat (4) includes a shell (41) which is covered on the front side wall of the cylinder body (2), and a water inlet chamber (42) and a water return chamber (43) are formed between the shell (41) and the cylinder body (2). A heat exchange channel (23) and a water return channel (25) are vertically opened in the cylinder body (2), the lower end of the heat exchange channel (23) is connected to the upper end of the water inlet channel (12), the upper end of the heat exchange channel (23) is connected to the water inlet chamber (42), the lower end of the water return channel (25) is connected to the upper end of the water outlet channel (13), and the upper end of the water return channel (25) is connected to the water return chamber (43).

2. The cooling structure of a motorcycle engine according to claim 1, characterized in that: The upper end of the front side wall of the box body (1) is tilted forward so that the upper ends of the two heat dissipation ribs (11) are tilted forward. The lower portion of the front side wall of the box body (1) has an oil cooling mounting seat (15) protruding forward. The oil cooler (5) is fixedly mounted on the front end surface of the oil cooling mounting seat (15). The oil cooling mounting seat (15) is located below the two heat dissipation ribs (11), and the lower ends of the two heat dissipation ribs (11) extend downward to the upper side surface of the oil cooling mounting seat (15).

3. The cooling structure of a motorcycle engine according to claim 2, characterized in that: A long strip-shaped guide groove (14) is formed between the two heat dissipation ribs (11), the upper end of the guide groove (14) is inclined forward, and the lower end extends to the upper side surface of the oil cooling mounting seat (15).

4. The cooling structure of a motorcycle engine according to claim 3, characterized in that: The oil cooler (5) is in the shape of a rectangular block. The oil cooler (5) is located below the two heat dissipation ribs (11). The angle between the upper side surface of the oil cooler (5) and the heat dissipation ribs (11) is an acute angle.

5. The motorcycle engine cooling structure according to any one of claims 1 to 4, characterized in that: The water inlet chamber (42) is connected to the upper water jacket (31), the upper end of the water inlet channel (12) is connected to the water inlet chamber (42), and the upper end of the water outlet channel (13) is connected to the return water chamber (43).

6. The cooling structure of a motorcycle engine according to claim 5, characterized in that: The housing (41) further comprises a water outlet chamber (44), the return water chamber (43) comprises a return water interface (431) for connecting to the water outlet of the radiator, and the water outlet chamber (44) comprises a water outlet interface (441) for connecting to the water inlet of the radiator. The cylinder body (2) comprises a lower water jacket (21), the return water chamber (43) is connected to the lower water jacket (21), the water inlet chamber (42) is connected to the water outlet chamber (44), and the return water chamber (43) is connected to the water outlet chamber (44) via a water outlet (45). The housing (41) further comprises a valve core (46) capable of controlling the opening and closing of the water outlet (45) and the water outlet interface (441).

7. The cooling structure of a motorcycle engine according to claim 6, characterized in that: A buffer chamber (24) is further provided in the cylinder body (2), and the buffer chamber (24) is located between the heat exchange channel (23) and the water inlet channel (12), and the lower end of the heat exchange channel (23) extends downwardly through the top surface of the buffer chamber (24), and the upper end of the water inlet channel (12) extends downwardly through the bottom surface of the buffer chamber (24).

8. The cooling structure of a motorcycle engine according to claim 6, characterized in that: The water inlet chamber (42) is located above the water return chamber (43). The water return chamber (43) has a columnar, vertically arranged heat exchange portion (22). The heat exchange channel (23) is vertically opened in the heat exchange portion (22).

9. The cooling structure of a motorcycle engine according to claim 8, characterized in that: The side wall of the cylinder body (2) has two through-holes (26) communicating with the lower water jacket (21) and the return water chamber (43). The heat exchange portion (22) is approximately located in the middle of the return water chamber (43) in the width direction and protrudes forward. The two through-holes (26) are respectively located on both sides of the heat exchange portion (22).

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