Engine air duct

Abstract

The utility model discloses an engine air duct which comprises an air inlet formed in a crankcase of an engine, an air guide cavity formed in the position, corresponding to a driving wheel assembly, of the inner side face of a crankcase cover of the engine, an upper air outlet and a lower air outlet. The air guide cavity is defined by the inner side face of the crankcase cover and an air guide partition plate arranged on the inner side face of the crankcase cover. An air guide opening is coaxially formed in the side, facing the driving wheel assembly, of the air guide cavity, the air guide opening is used for enabling the air guide cavity to communicate with the cavity where the driving wheel assembly is located, and the driving wheel assembly and the driven wheel assembly are both arranged in the cavity; the air guide cavity is further provided with a ventilation opening communicating with the air inlet. The upper air outlet is formed in the crankcase and is close to and located above the driven wheel assembly, the lower air outlet is formed in the crankcase and located below the driven wheel assembly, and cold air at the air guide opening can be aligned with the driving wheel assembly for cooling and can flow to the upper portion and the lower portion of the driven wheel assembly correspondingly. And heat generated in the operation process of the engine in the cavity is effectively taken away.

Description

Technical Field

[0001] This utility model belongs to the field of motorcycle engine technology, specifically relating to an engine air duct. Background Technology

[0002] The crankcase is an indispensable part of the overall structure of a motorcycle engine. During operation, the engine's power system is prone to high internal temperatures due to poor heat dissipation. If the components are kept at their maximum operating temperature for a long time, they are prone to wear or breakage, thereby reducing the engine's service life. Utility Model Content

[0003] In view of the technical problems existing in the prior art, this utility model provides an engine air duct.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] An engine air duct, comprising:

[0006] The air intake is located on the engine crankcase;

[0007] An air guide chamber is located on the inner side of the crankcase cover of the engine, corresponding to the position of the drive wheel assembly. The air guide chamber is enclosed by the inner side of the crankcase cover and an air guide baffle disposed thereon. An air guide port is coaxially disposed on the side of the air guide chamber facing the drive wheel assembly. The air guide port is used to connect the air guide chamber with the chamber where the drive wheel assembly is located. Both the drive wheel assembly and the driven wheel assembly are disposed in the chamber. The air guide chamber is also provided with a ventilation opening that communicates with the air inlet.

[0008] An upper air outlet, located on the crankcase near and above the driven wheel assembly, allows gas arriving at this location to exit the chamber; and

[0009] The lower air outlet is located on the crankcase and below the driven wheel assembly, for allowing gas arriving at this location to flow out of the chamber.

[0010] Furthermore, the engine air duct also includes a first spiral air guide section, which is disposed on the chamber and distributed around the outer edge of the drive wheel assembly away from the driven wheel assembly. The input end of the first spiral air guide section is located above the drive wheel assembly, and the output end of the first spiral air guide section extends downward and toward the lower air outlet after passing around the outer edge of the drive wheel assembly away from the driven wheel assembly. The first spiral air guide section guides a portion of the gas from the air guide port to the lower air outlet and a position on the driven wheel assembly near the first spiral air guide section. A portion of the gas passing through the first spiral air guide section flows out from the lower air outlet, and the other portion flows toward the upper air outlet and flows out from the upper air outlet.

[0011] The second spiral air guide is disposed on the side of the air guide chamber facing the driving wheel assembly and distributed on the outer edge of the driving wheel assembly away from the driven wheel assembly. One end of the second spiral air guide is located above the driving wheel assembly, and the other end faces the driven wheel assembly. The second spiral air guide directs another part of the gas from the air guide port to the driven wheel assembly.

[0012] Furthermore, the engine air duct also includes a third spiral air guide section disposed on the chamber and distributed around the outer edge of the driven wheel assembly away from the outer edge of the driving wheel assembly. The air inlet end of the third spiral air guide section corresponds to the other end of the second spiral air guide section, and the air outlet end of the third spiral air guide section is close to the upper air outlet. The third spiral air guide section is used to guide the gas from the second spiral air guide section to the upper air outlet.

[0013] Furthermore, the crankcase is provided with an appendage to divide the internal space of the crankcase into two parts. The cavity is formed between the appendage and the crankcase cover. The driving wheel portion of the driving wheel assembly, the driven wheel portion of the driven wheel assembly, and the transmission portion are all disposed in the cavity. The air inlet is disposed on the appendage and communicates with the cavity. The appendage is provided with an appendage air duct. One end of the appendage air duct is connected to the air inlet, and the other end is connected to the air guide cavity through the ventilation opening.

[0014] Furthermore, the appendage has a front wall facing the crankcase cover and a peripheral wall extending from the periphery of the front wall toward the crankcase cover, and the air inlet and the upper air outlet are both disposed on the peripheral wall; the first spiral air guide and the third spiral air guide are disposed near the edge of the front wall.

[0015] Furthermore, an air guide shroud communicating with the upper air outlet is provided. The air guide shroud has a lateral opening and is used to change the direction of the gas from the upper air outlet so that the gas flows out laterally from the lateral opening of the air guide shroud.

[0016] Furthermore, the inner side of the crankcase cover has a groove with an opening facing the drive wheel assembly, and the air guide baffle is disposed at the opening of the groove to enclose and form the air guide chamber; the vent is disposed on the groove wall of the groove facing the upper end of the crankcase cover to communicate with the air inlet.

[0017] Furthermore, the portion of the groove wall away from the driven wheel assembly protrudes from the air guide baffle towards the driving wheel assembly, and the portion of the groove wall protruding from the air guide baffle is open towards the driven wheel assembly and close to the first spiral air guide portion.

[0018] Furthermore, a first slot is provided on the groove at the location of the vent. The air guide baffle includes a plate with the air guide and a limiting part fixedly connected to the plate. The plate is detachably connected to the crankcase cover to cover the opening of the groove. The limiting part has a limiting lug corresponding to the position of the first slot and can be slidably assembled in the first slot.

[0019] Furthermore, the engine air duct also includes an impeller, which is disposed on one side of the drive wheel assembly facing the air guide baffle, for pressurizing and accelerating the gas from the air guide chamber.

[0020] In summary, the beneficial effects of this utility model are as follows: 1. By introducing cold air through the air inlet and guiding it through the air guide chamber, it effectively removes the heat generated during operation, preventing these critical components from experiencing performance degradation, accelerated wear, or even damage due to overheating, thus ensuring the normal and reliable operation of the entire engine. 2. The first spiral air guide is located at the outer edge of the drive wheel assembly, allowing for targeted airflow into the chamber. It first cools the drive wheel portion before acting on its outer edge area. Furthermore, when rotating clockwise, some airflow also cools the driven wheel portion near the drive wheel. The first spiral air guide enhances local heat exchange in the drive wheel, preventing localized overheating and ensuring comprehensive heat dissipation of the drive wheel assembly. The second spiral air guide directs airflow to the center of the driven wheel assembly, achieving targeted cooling of the core area and preventing localized overheating and performance degradation caused by poor heat dissipation in the central area, thus ensuring stable operation of the driven wheel assembly. The third spiral air guide can guide the airflow along the outer edge of the driven wheel section, facilitating heat exchange and cooling on its outer side. Simultaneously, it assists in heat dissipation on the inner side of the driving wheel section, further enhancing the overall cooling effect. The second spiral air guide utilizes the groove wall structure on the crankcase cover, eliminating the need for numerous additional complex components or excessive space occupation. This optimizes the layout of the air duct within the engine chamber, making the air duct system more compact, efficient, and rational. When the driving and driven wheel assemblies rotate, each spiral air guide directs airflow within the chamber, promoting air convection between the upper and lower areas, driving air circulation throughout the chamber, enhancing heat transfer and dissipation between different locations, helping to maintain temperature uniformity within the chamber, and improving overall heat dissipation performance. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of an engine air duct provided by this utility model.

[0022] Figure 2 This is the front view of the diagram.

[0023] Figure 3 yes Figure 2 Sectional view along the AA direction.

[0024] Figure 4 This is a cross-sectional view of the central chamber of this utility model.

[0025] Figure 5 This is a three-dimensional structural diagram of the engine without the crankcase cover in this utility model.

[0026] Figure 6 yes Figure 5 The main view.

[0027] Figure 7This is a schematic diagram of the crankcase cover without an air guide baffle in this utility model.

[0028] Figure 8 This is a three-dimensional structural diagram of the crankcase cover after the air guide baffle is installed in this utility model.

[0029] Figure 9 yes Figure 8 The main view.

[0030] Figure 10 This is a schematic diagram of the air guide baffle in this utility model.

[0031] Figure 11 yes Figure 10 A sectional view.

[0032] In the diagram, 100-crankcase, 110-air inlet pipe, 111-air inlet, 120-chamber, 121-first spiral air guide, 122-third spiral air guide, 130-attachment, 131-attachment air duct, 132-front wall, 133-peripheral wall, 134-air guide cover, 200-crankcase cover, 210-air guide baffle, 211-plate, 2110-air guide port, 212-limiting part, 2120-limiting support, 220-air guide chamber, 221-ventilation port, 230-groove, 240-second spiral air guide, 250-first slot, 260-second slot, 300-drive wheel assembly, 310-impeller, 311-blade, 400-driven wheel assembly, 500-lower air outlet plate, 510-lower air outlet. Detailed Implementation

[0033] The present invention will be further explained below with reference to specific illustrations.

[0034] Please see Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 6 This utility model provides an engine air duct, including an air inlet 111, an air guide chamber 220, an upper air outlet, and a lower air outlet 510 disposed on the crankcase 100 of the engine. The air guide chamber 220 is disposed on the inner side of the crankcase cover 200 of the engine, corresponding to the position of the drive wheel assembly 300, and is enclosed by the inner side of the crankcase cover 200 and an air guide baffle 210 disposed thereon. An air guide port 2110 is coaxially disposed on the side of the air guide chamber 220 facing the drive wheel assembly 300, and the air guide port 2110 is used to communicate the air guide chamber 220 with the chamber 120 where the drive wheel assembly 300 is located. Both the drive wheel assembly 300 and the driven wheel assembly 400 are disposed within the chamber 120. The air guide chamber 220 is also provided with a vent 221 communicating with the air inlet 111.

[0035] An upper air outlet is located on the crankcase 100 near and above the driven wheel assembly 400, for allowing gas arriving at this location to exit the chamber 120. A lower air outlet 510 is located on the crankcase 100 and below the driven wheel assembly 400, for allowing gas arriving at this location to exit the chamber 120. Those skilled in the art will understand that the terms "above" and "below" can refer to directly above, directly below, diagonally above, or diagonally below the driven wheel assembly 400. In this embodiment, the upper air outlet is located diagonally above the driven wheel assembly 400 (biased away from the driving wheel assembly 300), and the lower air outlet 510 is located diagonally below the driven wheel assembly 400 (biased away from the driving wheel assembly 300). Specifically, an air guide shroud 134 is installed at the upper air outlet and is connected to it. The air guide shroud 134 has a lateral opening. The air guide shroud 134 is used to change the direction of the air from the upper air outlet so that the air flows out laterally from the lateral opening of the air guide shroud 134. This prevents the hot air blown out of the upper air outlet from blowing directly upwards onto the rider and affecting the overall riding experience of the vehicle.

[0036] The cool air outside the crankcase 100 is guided by the air inlet 111 through the air guide chamber 220, enters the chamber 120 through the air guide port 2110, and is directed to the drive wheel assembly 300 for heat exchange and cooling. As the drive wheel assembly 300 and the driven wheel assembly 400 rotate, the cool air at the air guide port 2110 flows to the top and bottom of the driven wheel assembly 400 respectively, and then flows out from the corresponding air outlets. This effectively removes the heat generated by the drive wheel assembly 300 and the driven wheel assembly 400 during operation, preventing performance degradation, accelerated wear of parts, or even damage due to overheating. This ensures the normal and reliable operation of the entire transmission system and also helps maintain the engine within a suitable operating temperature range, extending the engine's service life.

[0037] Please continue reading. Figure 3The crankcase 100 is provided with an appendage 130, which divides the internal space of the crankcase 100 into two parts. The appendage 130 is located between the crankcase 100 and the crankcase cover 200 and is screwed to both the crankcase 100 and the crankcase cover 200. The screwed connection of the crankcase 100, appendage 130, and crankcase cover 200 facilitates disassembly and assembly, and makes it easy to replace and repair worn parts. A chamber 120 is formed between the appendage 130 and the crankcase cover 200. The driving wheel portion of the driving wheel assembly 300, the driven wheel portion of the driven wheel assembly 400, and the transmission components are all disposed within the chamber 120. In this way, components that are in operation for a long time can be placed in an independent chamber 120. By drawing in external cold air from the air inlet 111 into the chamber 120, effective heat dissipation and a good air environment can be created for the driving wheel, driven wheel and transmission parts in the chamber 120, which can ensure the transmission accuracy and transmission efficiency of the driving wheel, driven wheel and transmission parts.

[0038] Please see Figure 5 and Figure 6 The attachment 130 has a front wall 132 facing the crankcase cover 200 and a peripheral wall 133 extending from the periphery of the front wall 132 toward the crankcase cover 200. The air inlet 111 and the upper air outlet mentioned above are both provided on the peripheral wall 133. The first spiral air guide section 121 (dashed line B part) and the third spiral air guide section 122 (dashed line C part) are provided near the edge of the front wall 132. The first spiral air guide section 121 and the third spiral air guide section 122 cooperate with the crankcase 100 to guide air.

[0039] The appendage 130 is equipped with an air inlet pipe 110, the port of which is defined as an air inlet 111 communicating with the chamber 120. The appendage 130 also has an appendage air duct 131, one end of which is connected to the air inlet 111, and the other end is connected to the air guide chamber 220 via a vent 221. The appendage air duct 131 provides a clear and fixed flow path for the incoming cold air, allowing it to follow a pre-designed route, passing sequentially through the air inlet 111, the appendage air duct 131, and the vent 221, ultimately reaching the air guide chamber 220, and then flowing into the chamber 120 containing the driving wheel, driven wheel, and transmission components. This precisely delivers cold air to critical areas requiring heat dissipation, preventing disordered, dispersed, or ineffective airflow to the target area, improving the targeting and effectiveness of ventilation and heat dissipation, and ensuring efficient heat exchange and cooling for important components such as the driving and driven wheels.

[0040] Please continue reading. Figure 6The engine air duct also includes a first spiral air guide section 121, a second spiral air guide section 240, and a third spiral air guide section 122. The first spiral air guide section 121 is disposed on the chamber 120 around the outer edge of the drive wheel assembly 300 away from the driven wheel assembly 400, and the input end of the first spiral air guide section 121 is located above the drive wheel assembly 300. The output end of the first spiral air guide section 121 extends downward and toward the lower air outlet 510 around the outer edge of the drive wheel assembly 300 away from the driven wheel assembly 400. The distance between the first spiral air guide section 121 and the drive wheel part gradually increases from the input end to the output end. The air pressure is higher at the narrower distance and lower at the wider distance. Therefore, when the drive wheel part rotates clockwise, air flows more easily from the high-pressure area to the low-pressure area, making it easier for air to flow out from the air outlet.

[0041] The first spiral air guide 121 guides a portion of the gas from the air guide 2110 to the lower air outlet 510 and a position on the driven wheel assembly 400 near the first spiral air guide 121. The first spiral air guide 121 is located on the driving wheel assembly 300 away from the outer edge of the driven wheel assembly 400. It can specifically guide a portion of the gas entering the chamber 120 from the air guide 2110, so that this portion of cold air is actually aimed at the driving wheel part for cooling first, and then directly acts on the outer edge area of ​​the driving wheel part on that side. This can enhance the heat exchange of this local part of the driving wheel part, avoid local overheating due to poor heat dissipation, and thus more comprehensively ensure the overall heat dissipation effect of the driving wheel assembly 300 and maintain its good working condition.

[0042] Please continue reading. Figure 6When the drive wheel assembly 300 is working, it rotates clockwise. Part of the gas passing through the first spiral air guide 121 flows out from the lower air outlet 510, while the other part flows to the upper air outlet and flows out from the upper air outlet. This process promotes air convection between the upper and lower areas within the chamber 120, drives the circulation of air throughout the entire chamber 120, enhances the transfer and dissipation of heat between different locations, helps maintain the temperature uniformity within the chamber 120, and improves the overall heat dissipation performance, as well as the air flowing out from the upper air outlet. The first spiral air guide 121 can guide the gas to the third spiral air guide 122 near the driven wheel assembly 400. After being guided by the third spiral air guide 122, the gas can flow out from the upper air outlet, and there is also airflow to dissipate heat on the part of the driven wheel assembly 400 near the driving wheel (i.e., the inner side of the driven wheel assembly 400, near the driving wheel assembly), providing additional assistance for the heat dissipation of the driven wheel assembly 400. The part of cold air guided by the first spiral air guide 121 can further enhance the cooling effect on the corresponding position of the driven wheel assembly 400, and more comprehensively ensure the heat dissipation of the driven wheel assembly 400, ensuring that it will not affect the transmission efficiency and accuracy due to overheating during long-term operation.

[0043] Please continue reading. Figure 4 The drive wheel assembly 300 has an impeller 310 arranged clockwise on one side facing the guide vane 200, which is used to pressurize and accelerate the gas from the guide chamber 220. The impeller 310 includes several blades 311 distributed around the center of the impeller 310. Each blade 311 is curved in a clockwise arc, which can accelerate the gas from the guide chamber 220 and guide it to the first spiral guide section 121 and the second spiral guide section 240. When the engine is working, the impeller 310 rotates clockwise and blows air from the center of the impeller 310 to the outer edge, forcibly pressurizing and accelerating the cold air entering through the air guide port 2110. This significantly increases the cold air velocity, and the high-speed cold air can more quickly pass over the surfaces of components that need heat dissipation, such as the drive wheel assembly 300, the driven wheel assembly 400, and the transmission parts. This increases the number of contacts with these heat-generating components per unit time, thereby enhancing the heat exchange process.

[0044] The second spiral air guide 240 is disposed on the side of the air guide chamber 220 facing the driving wheel assembly 300, and the second spiral air guide 240 is located on the outer edge of the driving wheel assembly 300 away from the driven wheel assembly 400. One end of the second spiral air guide 240 is located above the driving wheel assembly 300, and the other end faces the driven wheel assembly 400. The distance between the second spiral air guide 240 and the center of the air guide port 2110 gradually increases from the one end to the other end, and the effect of the gradually increasing distance is the same as that of the first spiral air guide 121. The second spiral air guide 240 directs another portion of the gas from the air guide 2110 to the driven wheel assembly 400. The function of the second spiral air guide 240 is to guide the air coming out of the air guide 2110 to the driven wheel assembly 400 in an orderly manner. The cold air can directly act on the core area of ​​the driven wheel assembly 400, achieving targeted cooling of the driven wheel assembly 400, enhancing the heat dissipation effect of the driven wheel part, and avoiding problems such as local overheating and performance degradation of the entire driven wheel assembly 400 due to poor heat dissipation in the central area, thus ensuring the stable operation of the driven wheel assembly 400. After the clockwise rotation of the driven wheel assembly 400, the air is guided to flow out from the lower air outlet 510. At the same time, some air reaches the third spiral air guide 122 and is guided to flow out from the upper air outlet.

[0045] Please see Figure 7 and Figure 8 The inner side of the crankcase cover 200 has a groove 230 with an opening facing the drive wheel assembly 300. A baffle 210 is disposed at the opening of the groove 230 to enclose it and form a baffle chamber 220. A vent 221 is disposed on the groove wall of the groove 230 facing the upper end of the crankcase cover 200 to communicate with the air inlet 111. A portion of the groove wall of the groove 230 away from the driven wheel assembly 400 protrudes from the baffle 210 towards the drive wheel assembly 300. This protruding portion of the groove wall faces the driven wheel assembly 400 and is close to the first spiral air guide section 121. The second spiral air guide section 240 is designed using the groove wall structure of the recess 230 on the crankcase cover 200. The part protruding from the air guide baffle 210 serves as the second spiral air guide section 240. This ingenious design, which combines with the existing structure, effectively guides the airflow from the air guide port 2110 without adding a large number of complex components or occupying too much space. This optimizes the layout of the air duct within the entire engine chamber 120, making the air duct system more compact, efficient, and rational. Furthermore, by precisely guiding the airflow to the driven wheel assembly 400, the heat dissipation effect of the driven wheel is enhanced.

[0046] After the engine starts, the drive wheel will keep rotating with the engine, so the air flowing out of the air vent can be guided to the driven wheel very quickly.

[0047] Please see Figure 7 A first slot 250 is provided on the groove 230 at the position of the vent 221. Please refer to [link / reference]. Figure 10 and Figure 11 The air guide baffle 210 includes a plate 211 with an air guide port 2110 and a limiting part 212 fixedly connected to the plate 211. The plate 211 is detachably connected to the crankcase cover 200 to cover the opening of the groove 230. The limiting part 212 has a limiting lug 2120 that corresponds to the position of the first slot 250 and can be slidably fitted into the first slot 250. After the limiting lug 2120 is installed in the corresponding first slot 250, it can initially position the air guide baffle 210. In order to make the air guide baffle 210 more stable, the plate 211 is also bolted to the crankcase cover 200. The air guide baffle 210 connected in this way is easy to install and easy to disassemble and maintain.

[0048] Please see Figure 8 and Figure 9 The crankcase cover 200 has a notch on its side wall that communicates with the interior, and a second slot 260 is provided at the edge of the notch. A lower air outlet 500 is inserted into the second slot 260, and the lower air outlet 500 has several lower air outlets 510. The lower air outlets 510 can be located directly below or diagonally below the driven wheel section.

[0049] The third spiral air guide section 122 is disposed on the chamber 120, distributed around the outer edge of the driven wheel assembly 400 away from the driving wheel assembly 300. The air inlet end of the third spiral air guide section 122 corresponds to the other end of the second spiral air guide section 240, and the air outlet end of the third spiral air guide section 122 is close to the upper air outlet. The third spiral air guide section 122 is used to guide the gas from the second spiral air guide section 240 to the upper air outlet. The distance between the third spiral air guide section 122 and the center of the driven wheel assembly gradually increases from the air inlet end to the air outlet end. As the engine starts, the driven wheel assembly 400 rotates clockwise. In addition, the third spiral air guide section 122 guides the gas from the outer edge of the driven wheel part to the upper air outlet, performing heat exchange and cooling on the outer side of the driven wheel part. As the driven wheel assembly 400 rotates clockwise, air is also guided to the first spiral air guide section 121, and then guided by the first spiral air guide section 121, the air is drawn out from the lower air outlet 510. During the clockwise rotation, a small amount of air will be directed to the position of the driving wheel near itself (i.e., the inner side of the driving wheel, near the driven wheel). Finally, this part of the air flows out from the lower air outlet 510, which can also perform heat exchange and cooling on the inner side of the driving wheel.

[0050] The engine's airflow system has two main functions: First, it introduces cool air through the air inlet 111, which is then guided through the air guide chamber 220 to exchange heat with and cool the drive wheel assembly 300, driven wheel assembly 400, and transmission components. This effectively removes heat generated during operation, preventing performance degradation, accelerated wear, or even damage to these critical components due to overheating, thus ensuring the normal and reliable operation of the entire engine. Second, the first spiral air guide section 121 is located at the outer edge of the drive wheel assembly 300. It can selectively guide a portion of the gas entering the chamber 120, first cooling the drive wheel section and then its outer edge area. Furthermore, when rotating clockwise, some airflow can also cool the driven wheel section near the drive wheel. The first spiral air guide section 121 enhances local heat exchange in the drive wheel, preventing localized overheating and comprehensively ensuring the heat dissipation effect of the drive wheel assembly 300. The second spiral air guide 240 guides air to the driven wheel assembly 400, cooling it and preventing localized overheating and performance degradation caused by poor heat dissipation in the central area, thus ensuring stable operation of the driven wheel assembly 400. The third spiral air guide 122 guides the airflow to the outer edge of the driven wheel section, facilitating heat exchange and cooling on its outer side. It also assists in heat dissipation on the inner side of the driving wheel section, further improving overall heat dissipation. Thirdly, the second spiral air guide 240 utilizes the groove wall structure of the recess 230 on the crankcase cover 200, eliminating the need for numerous additional complex components or excessive space occupation. This optimizes the layout of the air duct within the engine chamber 120, making the air duct system more compact, efficient, and rational. Fourth, when the drive wheel assembly 300 and the driven wheel assembly 400 rotate, each spiral air guide guides the airflow within the chamber 120, promoting air convection between the upper and lower areas within the chamber 120, driving the air circulation within the entire chamber 120, enhancing heat transfer and dissipation between different locations, helping to maintain the temperature uniformity within the chamber 120, and improving the overall heat dissipation performance.

[0051] The above are merely embodiments of this utility model and do not limit the patent scope of this utility model. Any equivalent structure made using the contents of this utility model specification and drawings, whether directly or indirectly applied to other related technical fields, shall also be within the patent protection scope of this utility model.

Claims

1. An engine air duct, characterized in that, include: The air intake is located on the engine crankcase; An air guide chamber is located on the inner side of the crankcase cover of the engine, corresponding to the position of the drive wheel assembly. The air guide chamber is enclosed by the inner side of the crankcase cover and an air guide baffle disposed thereon. An air guide port is coaxially disposed on the side of the air guide chamber facing the drive wheel assembly. The air guide port is used to connect the air guide chamber with the chamber where the drive wheel assembly is located. Both the drive wheel assembly and the driven wheel assembly are disposed in the chamber. The air guide chamber is also provided with a ventilation opening that communicates with the air inlet. An upper air outlet, located on the crankcase near and above the driven wheel assembly, allows gas arriving at this location to exit the chamber; and The lower air outlet is located on the crankcase and below the driven wheel assembly, for allowing gas arriving at this location to flow out of the chamber.

2. The engine air duct as described in claim 1, characterized in that, Also includes: A first spiral air guide is disposed on the chamber, distributed around the outer edge of the driving wheel assembly away from the driven wheel assembly. The input end of the first spiral air guide is located above the driving wheel assembly, and the output end of the first spiral air guide extends downward and toward the lower air outlet after passing around the outer edge of the driving wheel assembly away from the driven wheel assembly. The first spiral air guide directs a portion of the gas from the air guide to the lower air outlet and a position on the driven wheel assembly near the first spiral air guide. A portion of the gas passing through the first spiral air guide flows out from the lower air outlet, and the other portion flows toward the upper air outlet and flows out from the upper air outlet. The second spiral air guide is disposed on the side of the air guide chamber facing the driving wheel assembly and distributed on the outer edge of the driving wheel assembly away from the driven wheel assembly. One end of the second spiral air guide is located above the driving wheel assembly, and the other end faces the driven wheel assembly. The second spiral air guide directs another part of the gas from the air guide port to the driven wheel assembly.

3. The engine air duct as described in claim 2, characterized in that: It also includes a third spiral air guide section disposed on the chamber and distributed around the outer edge of the driven wheel assembly away from the driving wheel assembly. The air inlet end of the third spiral air guide section corresponds to the other end of the second spiral air guide section, and the air outlet end of the third spiral air guide section is close to the upper air outlet. The third spiral air guide section is used to guide the gas from the second spiral air guide section to the upper air outlet.

4. The engine air duct as described in claim 3, characterized in that: The crankcase is provided with an appendage to divide the internal space of the crankcase into two parts. The cavity is formed between the appendage and the crankcase cover. The driving wheel part of the driving wheel assembly, the driven wheel part of the driven wheel assembly, and the transmission part are all disposed in the cavity. The air inlet is disposed on the appendage and communicates with the cavity. The appendage is provided with an appendage air duct. One end of the appendage air duct is connected to the air inlet, and the other end is connected to the air guide cavity through the ventilation opening.

5. The engine air duct as described in claim 4, characterized in that: The attachment has a front wall facing the crankcase cover and a peripheral wall extending from the periphery of the front wall toward the crankcase cover. The air inlet and the upper air outlet are both disposed on the peripheral wall. The first spiral air guide and the third spiral air guide are disposed near the edge of the front wall.

6. The engine air duct as described in claim 1, characterized in that: An air guide shroud is provided at the upper air outlet and communicates with it. The air guide shroud has a side opening and is used to change the direction of the gas from the upper air outlet so that the gas flows out laterally from the side opening of the air guide shroud.

7. The engine air duct as described in claim 2, characterized in that: The inner side of the crankcase cover has a groove with an opening facing the drive wheel assembly. The air guide baffle is disposed at the opening of the groove to enclose and form the air guide chamber. The vent is disposed on the groove wall facing the upper end of the crankcase cover to communicate with the air inlet.

8. The engine air duct as described in claim 7, characterized in that: The portion of the groove wall away from the driven wheel assembly protrudes from the air guide baffle towards the driving wheel assembly, and the portion of the groove wall protruding from the air guide baffle is open towards the driven wheel assembly and close to the first spiral air guide section.

9. The engine air duct as described in claim 7, characterized in that: A first slot is provided on the groove at the position of the vent. The air guide baffle includes a plate with the air guide and a limiting part fixedly connected to the plate. The plate is detachably connected to the crankcase cover to cover the opening of the groove. The limiting part has a limiting lug that corresponds to the position of the first slot and can be slidably assembled in the first slot.

10. The engine air duct as described in any one of claims 1-9, characterized in that: It also includes an impeller, which is disposed on one side of the drive wheel assembly facing the air guide baffle, for pressurizing and accelerating the gas from the air guide chamber.

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