A two-stroke internal combustion engine, exhaust device and drone

Abstract

The utility model discloses a two -stroke internal -combustion engine, exhaust device and unmanned plane, wherein two -stroke internal -combustion engine includes cylinder and exhaust device, and exhaust device is directly or indirectly connected with the exhaust port of cylinder, and exhaust device includes: the tubular body, and the tubular body has the air inlet, the baffle group and the exhaust port who are arranged in proper order along the exhaust direction in, the air inlet is directly or indirectly connected with the exhaust port of the cylinder of two -stroke internal -combustion engine, the baffle group includes the back pressure baffle and the sound -absorbing baffle group who are arranged in proper order along the exhaust direction, and the space between back pressure baffle and the rear end inner wall of tubular body forms the sound -absorbing chamber, and the rear end of tubular body is the one end of tubular body close to the exhaust port of exhaust device, is provided with exhaust hole array on back pressure baffle and the sound -absorbing baffle group, and the space between back pressure baffle and the front end inner wall of tubular body forms the back pressure chamber, and the front end of tubular body is the one end of tubular body close to the air inlet, and the volume of back pressure chamber is a, and the displacement of the cylinder connected with back pressure chamber in two -stroke internal -combustion engine is b, and the numerical value of a is the numerical value of b 15 times ~ 25 times.

Description

Technical Field

[0001] This utility model relates to the field of two-stroke internal combustion engines, and more particularly to a two-stroke internal combustion engine, an exhaust device, and an unmanned aerial vehicle. Background Technology

[0002] Two-stroke internal combustion engines are a type of internal combustion engine that completes one working cycle in two strokes. They have advantages such as high power density and rapid start-up, and are widely used in equipment such as drones and motorboats.

[0003] During the operation of a two-stroke internal combustion engine, the exhaust phase often involves the loss of fresh combustible mixture, leading to decreased emission performance and poor fuel economy. To mitigate this issue, a muffler is typically installed at the exhaust port of a two-stroke internal combustion engine. Existing exhaust systems generally include a back pressure chamber and a muffler chamber. The back pressure chamber's function is to control the exhaust back pressure, prompting some unburned fresh mixture to return to the cylinder. The muffler chamber, on the other hand, guides the exhaust gases out and effectively reduces exhaust noise during the emission process.

[0004] Existing two-stroke internal combustion engines still face some technical challenges in practical applications: the noise generated during exhaust is relatively large, affecting the surrounding environment. Utility Model Content

[0005] Therefore, it is necessary to provide a two-stroke internal combustion engine, an exhaust device, and a drone to solve the problem of excessive noise generated during the exhaust process.

[0006] To achieve the above objectives, the inventor provides a two-stroke internal combustion engine, including a cylinder and an exhaust device, wherein the exhaust device is directly or indirectly connected to the exhaust port of the cylinder, and the exhaust device includes: a pipe body, wherein an air inlet, a baffle group and an exhaust port are sequentially arranged in the exhaust direction within the pipe body;

[0007] The air intake is directly or indirectly connected to the exhaust port of the cylinder of the two-stroke internal combustion engine.

[0008] The baffle assembly includes a backpressure baffle and a silencer baffle assembly arranged sequentially along the exhaust direction. The space between the backpressure baffle and the inner wall of the rear end of the pipe body forms a silencer chamber. The rear end of the pipe body is the end of the pipe body near the exhaust port of the exhaust device. Both the backpressure baffle and the silencer baffle assembly are provided with an array of exhaust through holes. The space between the backpressure baffle and the inner wall of the front end of the pipe body forms a backpressure chamber. The front end of the pipe body is the end of the pipe body near the air inlet. The volume of the backpressure chamber is a, and the displacement of the cylinder connected to the backpressure chamber in the two-stroke internal combustion engine is b, where the value of a is 15 to 25 times the value of b.

[0009] Further: the volume 'a' of the back pressure chamber is 1.6–2.6 L; or,

[0010] The volume 'a' of the back pressure chamber is 2.5 to 4.2 L.

[0011] Furthermore, the back pressure baffle is a curved surface that bulges out toward the sound-absorbing baffle assembly.

[0012] Furthermore: the sound-absorbing baffle assembly includes two or more sound-absorbing baffles, the back pressure baffle and the second sound-absorbing baffle are structurally mirror images of each other, the second sound-absorbing baffle is the one closest to the first sound-absorbing baffle in the sound-absorbing baffle assembly, and the first sound-absorbing baffle is the one closest to the back pressure baffle in the sound-absorbing baffle assembly.

[0013] Furthermore: the sound-absorbing baffle assembly includes two or more sound-absorbing baffles, the first sound-absorbing baffle is a curved surface protruding towards the back pressure baffle, and the first sound-absorbing baffle is the one closest to the back pressure baffle in the sound-absorbing baffle assembly.

[0014] Furthermore, the inner wall of the front end of the tube is a curved surface that bulges towards the air inlet.

[0015] Furthermore: the exhaust port of the exhaust device is located on the exhaust pipe, and the exhaust pipe extends into the silencer chamber from the rear end of the pipe body.

[0016] Further: the sound-absorbing baffle assembly includes two or more sound-absorbing baffles, the back pressure baffle and / or the sound-absorbing baffle includes a plate body and multiple protrusions, the plate body has a first vent hole, the protrusions have a second vent hole, the protrusions are fixed to the plate body and the second vent hole communicates with the first vent hole to form a venting through hole, one first vent hole corresponds to one protrusion; or,

[0017] The exhaust vents located on the back pressure baffle and / or the sound-absorbing baffle are formed by stamping the back pressure baffle and / or the sound-absorbing baffle; or,

[0018] The perforated plates on the back pressure baffle and / or the sound-absorbing baffle are bent toward the rear or front end of the pipe body, so that the original position of the back pressure baffle and / or the sound-absorbing baffle corresponding to the perforated plates forms the exhaust passage. The outer edge of the perforated plate is adapted to the inner edge of the exhaust passage, and the perforated plate is connected to the back pressure baffle and / or the sound-absorbing baffle through a connecting part.

[0019] To achieve the above objectives, the inventors also provide a two-stroke internal combustion engine exhaust device, wherein the exhaust device is the exhaust device described in any of the above embodiments.

[0020] To achieve the above objectives, the inventors provide an unmanned aerial vehicle (UAV) including a two-stroke internal combustion engine as described in any of the above embodiments.

[0021] Unlike existing technologies, the above technical solution has the following beneficial effects:

[0022] When a two-stroke internal combustion engine is running, high-temperature, high-pressure exhaust gas is discharged from the engine exhaust port and enters the intake port of this exhaust device. The exhaust gas first enters the back pressure chamber. Under the action of the back pressure baffle, some unburned fresh combustible mixture is effectively drawn into this chamber and flows back to the cylinder to participate in combustion. By optimizing the ratio between the back pressure chamber volume 'a' and the cylinder displacement 'b', i.e., 'a' is 15 to 25 times 'b', the exhaust back pressure can be made more stable and controllable, thereby effectively reducing the loss of fresh mixture, improving combustion efficiency and energy utilization, and enabling the two-stroke internal combustion engine to achieve a stable output close to its rated power. At the same time, another part of the exhaust gas enters the silencing chamber through the exhaust vent array on the back pressure baffle, and undergoes multiple reflections and attenuations in this chamber before finally being discharged through the exhaust port, significantly reducing exhaust noise.

[0023] The above description of the utility model is merely an overview of the technical solution of this application. In order to enable those skilled in the art to better understand the technical solution of this application and to implement it based on the description and drawings, and to make the above-mentioned objectives and other objectives, features and advantages of this application easier to understand, the following description is provided in conjunction with the specific embodiments and drawings of this application. Attached Figure Description

[0024] The accompanying drawings are only used to illustrate the principles, implementation methods, applications, features, and effects of specific embodiments of this utility model and other related contents, and should not be considered as limitations on this application.

[0025] Figure 1 This is a schematic diagram of the exhaust system of a two-stroke internal combustion engine in this embodiment;

[0026] Figure 2 This is a schematic diagram of the internal structure of the exhaust device in Embodiment 2;

[0027] Figure 3 This is a schematic diagram of the tubular component in some embodiments;

[0028] Figure 4 This is one of the exploded views of the back pressure baffle and the four sound-absorbing baffles in Example 1;

[0029] Figure 5 for Figure 4 Enlarged view of part A in the middle;

[0030] Figure 6 This is a schematic diagram of the exhaust port of the back pressure baffle in Example 1;

[0031] Figure 7 for Figure 6 Enlarged view of section C;

[0032] Figure 8 This is an exploded view of the back pressure baffle and the five sound-absorbing baffles in Example 3;

[0033] Figure 9 for Figure 8 Enlarged view of part B in the middle;

[0034] Figure 10 This is a schematic diagram of the exhaust pipe extending from the rear end of the pipe body into the silencing chamber and the silencing baffle in Embodiment 1;

[0035] Figure 11 This is a schematic diagram of the internal structure of the exhaust device in Embodiment 1;

[0036] Figure 12 This is the second exploded view of the back pressure baffle and the four sound-absorbing baffles in Example 1.

[0037] Explanation of reference numerals in the attached figures:

[0038] 1. Pipe body; 11. Air inlet; 12. Exhaust outlet; 13. Back pressure chamber; 14. Silencer chamber; 15. Exhaust pipe; 16. Front inner wall; 17. Rear inner wall; 18. Exhaust gas treatment device; 19. Tubular component;

[0039] 2. Back pressure baffle;

[0040] 3. Sound-absorbing barrier assembly; 31. First sound-absorbing barrier; 32. Second sound-absorbing barrier; 33. Third sound-absorbing barrier; 34. Fourth sound-absorbing barrier; 35. Fifth sound-absorbing barrier;

[0041] 4. Exhaust vent array; 41. Exhaust vent; 42. Plate; 43. Protrusion; 44. First exhaust vent; 45. Second exhaust vent;

[0042] 5. Perforated plate; 51. Connecting part. Detailed Implementation

[0043] To illustrate the possible application scenarios, technical principles, implementable specific solutions, and achievable objectives and effects of this application in detail, the following description, in conjunction with the listed specific embodiments and accompanying drawings, provides a detailed explanation. The embodiments described herein are merely illustrative of the technical solutions of this application and are therefore intended to limit the scope of protection of this application.

[0044] In this document, the term "embodiment" means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The term "embodiment" appearing in various places throughout the specification does not necessarily refer to the same embodiment, nor does it specifically limit its independence or connection with other embodiments. In principle, in this application, as long as there are no technical contradictions or conflicts, the technical features mentioned in each embodiment can be combined in any way to form corresponding implementable technical solutions.

[0045] Unless otherwise defined, the technical terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the use of related terms herein is merely for the purpose of describing particular embodiments and is not intended to limit this application.

[0046] In the description of this application, the term "and / or" is used to describe the logical relationship between objects, indicating that three relationships can exist. For example, A and / or B means: A exists, B exists, and A and B exist simultaneously. Additionally, the character " / " in this document generally indicates that the preceding and following objects have an "or" logical relationship.

[0047] In this application, terms such as “first” and “second” are used only to distinguish one entity or operation from another, and do not necessarily require or imply any actual quantity, hierarchy or order relationship between these entities or operations.

[0048] Without further limitations, the use of terms such as “comprising,” “including,” “having,” or other similar open-ended expressions in this application is intended to cover non-exclusive inclusion, which does not exclude the presence of additional elements in a process, method, or product that includes the stated elements, such that a process, method, or product that includes a list of elements may include not only those defined elements but also other elements not expressly listed, or elements inherent to such a process, method, or product.

[0049] Similar to the understanding in the Examination Guidelines, in this application, expressions such as "greater than," "less than," and "exceeding" are understood to exclude the stated number; expressions such as "above," "below," and "within" are understood to include the stated number. Furthermore, in the description of the embodiments in this application, "multiple" means two or more (including two), and similar expressions related to "multiple" are also understood in this way, such as "multiple groups" and "multiple times," unless otherwise explicitly specified.

[0050] In the description of the embodiments of this application, the space-related expressions used, such as "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "vertical," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential," indicate the orientation or positional relationship based on the orientation or positional relationship shown in the specific embodiments or drawings. They are only for the purpose of describing the specific embodiments of this application or for the reader's understanding, and do not indicate or imply that the device or component referred to must have a specific position, a specific orientation, or be constructed or operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0051] Unless otherwise expressly specified or limited, the terms "installation," "connection," "linking," "fixing," and "setting," as used in the description of the embodiments of this application, should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral arrangement; it can be a direct connection or an indirect connection through an intermediate medium; it can be a relationship of two components combined together, an interaction relationship between two components, or a connection within two structures. Those skilled in the art to which this application pertains can understand the specific meaning of the above terms in the embodiments of this application according to the specific circumstances.

[0052] Existing two-stroke internal combustion engines still face some technical challenges in practical applications. On the one hand, the noise generated during exhaust is relatively large, affecting the operating environment; on the other hand, the power output performance of internal combustion engines still needs improvement. The inventors discovered that an unreasonable design of the back pressure chamber volume can affect the power of a two-stroke internal combustion engine. For example, when the back pressure chamber volume is too small, it is difficult to form a stable back pressure environment, affecting combustion quality and thus limiting the improvement of the engine's output power.

[0053] Please see Figures 1 to 12 This embodiment provides a two-stroke internal combustion engine, including a cylinder and an exhaust device. The exhaust device is directly or indirectly connected to the exhaust port of the cylinder. The exhaust device includes a pipe body 1, and the pipe body 1 has an air inlet 11, a baffle group and an exhaust port 12 arranged sequentially along the exhaust direction.

[0054] The air intake 11 is directly or indirectly connected to the exhaust port of the cylinder of the two-stroke internal combustion engine.

[0055] The baffle assembly includes a backpressure baffle 2 and a noise-reducing baffle assembly 3 arranged sequentially along the exhaust direction. The space between the backpressure baffle 2 and the inner wall 17 at the rear end of the pipe body 1 forms a noise-reducing chamber 14. The rear end of the pipe body 1 is the end of the pipe body 1 near the exhaust port of the exhaust device. Both the backpressure baffle 2 and the noise-reducing baffle assembly 3 are provided with an exhaust through-hole array 4. The space between the backpressure baffle 2 and the inner wall 16 at the front end of the pipe body forms a backpressure chamber 13. The front end of the pipe body is the end of the pipe body 1 near the air inlet 11. The volume of the backpressure chamber 13 is a, and the displacement of the cylinder connected to the backpressure chamber 13 in the two-stroke internal combustion engine is b, where the value of a is 15 to 25 times the value of b.

[0056] Tube 1 is a hollow cylindrical structure, such as Figure 1 and Figure 2 In the embodiment shown, the air inlet 11 is located at one end of the pipe body 1, as shown... Figure 1 and Figure 2 The right end of the pipe body 1 can be fitted onto the exhaust port of a two-stroke internal combustion engine to collect the exhaust gas discharged from the engine. The exhaust port 12 is located at the other end of the pipe body 1, such as... Figure 1 and Figure 2 From the left end of the device, a portion of the treated waste gas is discharged. The exhaust direction is from the inlet 11 of the exhaust device towards the outlet 12. Figure 1 and Figure 2 The center also corresponds to the axial direction of tube 1, such as... Figure 2 As indicated by the middle arrow z.

[0057] A back pressure chamber 13 and a silencer chamber 14 are provided between the front and rear ends of the pipe body. Those skilled in the art should understand that the pipe body 1 is a structural concept and should not be rigidly interpreted as a mechanical component. That is, in this application, the pipe body is a tubular structure, in which the back pressure chamber 13 and the silencer chamber 14 are divided by a baffle group. In a specific exhaust device embodiment, this pipe body can be a separate component or it can be incorporated into a component. For example, in a tubular component 19, in addition to the pipe body described in this application, this tubular component 19 also has an exhaust gas treatment device 18 (e.g., a three-way catalytic converter) after the exhaust port 12, with the structure as follows: Figure 3 As shown, however, it should be understood that these additional devices do not belong to the structural concept of the tube body in the application. Just because the front or rear part of the tubular component has a structure other than the tube body in a specific embodiment does not mean that it does not have the "tube body" structure described in this application. It should be considered that as long as the device has a "tube body" structure that conforms to the description in this application and has the same function, it should be considered to conform to the relevant description in this application.

[0058] The volume a of the back pressure chamber 13 has the same unit as the cylinder displacement b, typically liters (L), although other units such as milliliters (mL) may be used in some embodiments. A larger volume ratio results in more stable power output at high engine speeds. At high ratios, the distance between the exhaust port 12 and the center of the back pressure chamber 13 is also shorter, accelerating gas reflection and making the engine more fuel-efficient and stable. Conversely, an excessively small back pressure chamber 13 volume affects the engine's operating efficiency. When the back pressure chamber 13 volume is too large, the pressure wave cannot reach the cylinder in time before the next engine stroke, leading to decreased combustion efficiency and consequently affecting the overall engine power.

[0059] When the two-stroke internal combustion engine is running, high-temperature, high-pressure exhaust gas is discharged from the engine exhaust port and enters the intake port 11 of the exhaust device. The exhaust gas first enters the back pressure chamber 13. Under the action of the back pressure baffle, some unburned fresh combustible mixture is effectively drawn into this chamber and flows back to the cylinder to participate in combustion. By optimizing the ratio between the back pressure chamber volume a and the cylinder displacement b, i.e., a is 15 to 25 times b, the exhaust back pressure can be made more stable and controllable, thereby effectively reducing the loss of fresh mixture, improving combustion efficiency and energy utilization, and enabling the two-stroke internal combustion engine to achieve a stable output close to the rated power. At the same time, another part of the exhaust gas enters the silencer chamber through the exhaust through-hole array on the back pressure baffle, and undergoes multiple reflections and attenuations in this chamber before finally being discharged through the exhaust port, significantly reducing exhaust noise.

[0060] Please see Figure 2 In some embodiments, the volume a of the back pressure chamber 13 is 1.600–2.600 L, and the displacement b of the cylinder connected to the back pressure chamber 13 in the two-stroke internal combustion engine is 0.064–0.173 L. This volume range provides an appropriate back pressure effect. If the back pressure chamber volume is too small, a stable back pressure environment is difficult to form, affecting combustion quality and thus limiting the increase in the internal combustion engine's output power. If the back pressure chamber volume is too large, the pressure wave cannot reach the cylinder in time before the next stroke of the internal combustion engine, leading to a decrease in combustion efficiency and affecting the overall engine power. By designing a reasonable relationship between the back pressure chamber 13 and the internal combustion engine's displacement, the airflow from the engine's exhaust port can form a stable local high-pressure zone after entering the back pressure chamber 13, while avoiding power loss or poor exhaust caused by excessive back pressure, allowing the internal combustion engine to reach its rated power.

[0061] Preferably, the displacement b of the cylinder connected to the back pressure chamber 13 in the two-stroke internal combustion engine can be set to 0.105L, and the rated power is 15kW (power unit, kilowatt). This internal combustion engine can be configured with one cylinder and one exhaust device, meaning each cylinder is connected to an independent exhaust device, and the engine has two cylinders and two exhaust devices. When the volume a of the back pressure chamber is 1.6–2.6L, such as 1.6L, 1.8L, or 2.6L, the internal combustion engine can achieve its rated power of 15kW; however, when the volume of the back pressure chamber is less than 1.6L, the actual output power of the two-stroke internal combustion engine can only reach approximately 13kW, failing to fully realize its design performance. In other embodiments, a design can also be adopted where one exhaust device connects to two cylinders simultaneously. In this case, the exhaust ports of the two cylinders are connected to the intake port of the same exhaust device through a confluence structure, sharing the same back pressure chamber and silencer structure.

[0062] In other embodiments, the volume a of the back pressure chamber 13 is 2.500 to 4.200 L, and the displacement b of the cylinder connected to the back pressure chamber 13 in the two-stroke internal combustion engine is 0.100 to 0.280 L. The combustion process of the two-stroke internal combustion engine is more complete, the acceleration of the internal combustion engine is more powerful, and the high-speed operation is more stable.

[0063] Please see Figure 2 , Figure 4 , Figure 8 , Figures 10 to 12 In some embodiments, the backpressure baffle 2 is a curved surface convex toward the sound-absorbing baffle assembly 3. The convex surface faces the air inlet 11, and the concave surface faces the exhaust outlet 12. The backpressure baffle 2 is machined into a rotating surface with a certain curvature (e.g., Figure 4 The curvature of the spherical surface shown can be adjusted according to actual operating conditions to match the exhaust characteristics of different engines. The curved shape allows some of the fresh combustible mixture to diffuse back and be re-drawn into the cylinder during the next intake stroke of the internal combustion engine.

[0064] Please see Figure 2 , Figure 4 , Figure 8 , Figures 10 to 12 In a further embodiment, the thickness of the back pressure baffle 2 is 0.5 to 1 mm, and metal back pressure baffles within this thickness range are easy to stamp into curved shapes.

[0065] In some embodiments, the sound-absorbing baffle group 3 includes two or more sound-absorbing baffles, all of which are curved surfaces protruding toward the back pressure baffle 2 or the inner wall 17 of the rear end of the pipe wall.

[0066] In some embodiments, the first noise-absorbing baffle 31 is a curved surface protruding towards the back pressure baffle 2, and the first noise-absorbing baffle 31 is the one closest to the back pressure baffle in the noise-absorbing baffle group 3.

[0067] In some embodiments, the back pressure baffle 2 and the second noise-absorbing baffle 32 are structurally mirror images of each other. The second noise-absorbing baffle 32 is the one closest to the first noise-absorbing baffle 31 in the noise-absorbing baffle group, and the first noise-absorbing baffle 31 is the one closest to the back pressure baffle 2 in the noise-absorbing baffle group 3.

[0068] Preferably, two or more sound-absorbing baffles are curved surfaces protruding towards the back pressure baffle 2 or the inner wall 17 at the rear end of the pipe. The multiple sound-absorbing baffles are placed side-by-side, and their curved surfaces face the same direction. When the sound-absorbing baffles are curved surfaces protruding towards the back pressure baffle 2, such as... Figure 10 , Figure 11 and Figure 12 As shown, this structure causes the exhaust port array to move backward, i.e., away from the back pressure baffle 2, extending the airflow path of the exhaust port array between the back pressure baffle 2 and the silencer baffle, enhancing the reflection and interference of exhaust gas between them, thereby further improving the noise reduction performance of the exhaust device. When the silencer baffle is a curved surface bulging towards the inner wall 17 at the rear end of the pipe, such as... Figure 2 and Figure 8 As shown, this structure can shorten the length of the exhaust system.

[0069] In some embodiments, the sound-absorbing baffle may be a flat plate, placed radially or obliquely along the tube body 1.

[0070] Please see Figure 2 , Figure 11 and Figure 12 In some embodiments, the inner wall 16 at the front end of the tube 1 is a curved surface that protrudes towards the air inlet 11, with the concave surface of the curved surface facing the back pressure baffle 2. Combined with the curved back pressure baffle 2, the back pressure chamber 13 forms a capsule shape, which helps to establish a more stable back pressure environment.

[0071] Please see Figure 2 , Figure 10 and Figure 11 In some embodiments, the exhaust port of the exhaust device is located on the exhaust pipe 15, which extends from the rear end of the pipe body 1 into the anechoic chamber 14. Extending the exhaust path allows the airflow to linger longer in the last space of the anechoic chamber 14, resulting in better noise reduction. Preferably, the exhaust pipe 15 can be positioned very close to the panel closest to the exhaust port 12 in the anechoic baffle assembly 3, for example... Figure 10 The exhaust pipe 15 extends from the rear into the concave surface of the curved fourth noise-reducing baffle 34, causing the airflow to bounce multiple times in this area, achieving more effective noise cancellation.

[0072] Please see Figure 2In some embodiments, to avoid poor exhaust due to excessively small through-holes, the area of ​​the exhaust through-hole array 4 is 550–935 mm². 2 (Area unit, square millimeters), the diameter of a single exhaust port 41 is 5-10 mm. This structure allows the exhaust gas after combustion to be discharged through the exhaust port 12 in a timely manner, avoiding excessive accumulation in the pipe body 1 and affecting the power of the internal combustion engine. The total area of ​​the exhaust port array 4 can be set to several different values ​​according to actual needs, such as 220 mm². 2 300mm 2 500mm 2 935mm 2 Meanwhile, the diameter of a single exhaust port 41 can also be selected according to the specific application, such as 5mm, 8mm, 10mm, etc.

[0073] In some embodiments, the exhaust port 41 can be designed in various shapes, including but not limited to round holes, square holes, or other geometric shapes (such as triangles, polygons, etc.), for example Figure 2 The exhaust vent 41 shown is round.

[0074] To meet the noise reduction requirements and manufacturing feasibility under different working conditions, the exhaust vents on the baffle (including the back pressure baffle 2 and the sound-absorbing baffle) described in this application can adopt the following three structural forms, which will be described in detail below.

[0075] Please see Figures 4 to 7 , Figures 10 to 12 In the first structural form, the sound-absorbing baffle group 3 includes two or more sound-absorbing baffles. The back pressure baffle 2 and / or the sound-absorbing baffle includes a plate body 42 and a plurality of protrusions 43. The plate body 42 has a first exhaust hole 44, and the protrusions 43 have a second exhaust hole 45. The protrusions 43 are fixed on the plate body 42 and the second exhaust hole 45 communicates with the first exhaust hole 44 to form an exhaust through hole 41. One first exhaust hole 44 corresponds to one protrusion 43. Figures 4 to 7 The exhaust vent structure on the backpressure baffle 2 is shown. The exhaust vent structure on the sound-absorbing baffle is the same and will not be shown in an enlarged view. Since the baffle has multiple exhaust vents 41, there are multiple protrusions 43. These protrusions 43 can be fixed to the plate body 42 by welding, snap-fitting, riveting, etc. The protrusions 43 have a certain length and protrude from the surface of the plate body 42. Airflow passes through the protrusions 43, enhancing energy consumption and further attenuating sound energy. This method has a superior noise reduction effect. Preferably, the protrusions 43 on the backpressure baffle 2 are at the rear end of the backpressure baffle 2, and the protrusions 43 on the sound-absorbing baffle are at the front end of the sound-absorbing baffle.

[0076] The protrusion 43 is a hollow annular structure. An annular groove can be provided on the plate 42 to fix the protrusion 43. The annular groove surrounds the first vent hole 44. The protrusion 43 can be placed into the annular groove 46 and welded to achieve the assembly of the protrusion 43 and the plate 42. The first vent hole 44 and the second vent hole 45 together form the vent hole 41. In some embodiments, the protrusion can be fixed to the inner wall of the first vent hole. In this case, the first vent hole is only used to support the protrusion 43 and is not part of the vent hole 41. In this case, the protrusion 43 serves as the vent hole 41.

[0077] In the first structural form, the distance between the two partitions is generally 15mm (length unit, millimeter), so the depth of the exhaust hole 41 is 8 to 10mm, which can be 8mm, 8.5mm, 9mm, 10mm, etc., which not only has a certain degree of noise reduction effect, but also controls the overall length.

[0078] Please see Figure 2 In the second structural form, the exhaust holes 41 located on the back pressure baffle 2 and / or the sound-absorbing baffle are formed by stamping a predetermined area on the baffle. Similarly, the exhaust holes 41 on the back pressure baffle 2 and / or the sound-absorbing baffle are formed by stamping the back pressure baffle 2 and / or the sound-absorbing baffle. The exhaust holes 41 on the back pressure baffle 2 are formed by stamping the back pressure baffle, and then the stamped portion completely separates from the back pressure baffle, forming an exhaust hole 41 at the stamped location.

[0079] Please see Figure 8 and Figure 9In the third structural form, the perforated plate 5 on the backpressure baffle 2 and / or the sound-absorbing baffle is bent toward the rear or front end of the pipe body 1, so that the exhaust through-hole 41 is formed at the position of the perforated plate 5 corresponding to the backpressure baffle 2 and / or the sound-absorbing baffle. The outer edge of the perforated plate 5 is adapted to the inner edge of the exhaust through-hole 41, and the perforated plate 5 is connected to the backpressure baffle 2 and / or the sound-absorbing baffle through the connecting part 51. The perforated plate 5 is originally part of the baffle. It can be bent toward the rear or front end of the pipe body 1 through a stamping process, thereby forming the exhaust through-hole 41 at that position. The perforated plate 5 is not completely separated from the baffle, but is kept connected to the baffle through the connecting part 51. The connecting part 51 is part of the plate body and is the boundary between the body and the perforated plate. Generally, the outer edge of the perforated plate 5 has the same shape as the inner edge of the exhaust through-hole 41, and the two are adapted to each other. However, in some embodiments, the perforated plate 5 can be trimmed to change its edge shape to adapt to different airflow disturbance design requirements. Located near the exhaust port 41, the perforated plate 5 can disturb the airflow as it passes through. When the airflow impacts the surface of the perforated plate 5, its direction is deflected, thereby enhancing energy dissipation, further weakening sound energy, and improving noise reduction performance.

[0080] Preferably, the perforated plate 5 is located at the rear end of the tube body 1. Figure 8 The diagram shows that the perforated plates 5 on the back pressure baffle 2 and the sound-absorbing baffle are both facing the rear end of the pipe body. After the exhaust gas passes through the exhaust port, it hits the perforated plates 5 and some of the sound energy is consumed.

[0081] The following are several different embodiments of the exhaust device for your reference:

[0082] Example 1

[0083] Please see Figures 4 to 8 , Figures 10 to 12 Along the direction from the air inlet 11 to the exhaust outlet 12, there are four noise-absorbing baffles: the first noise-absorbing baffle 31, the second noise-absorbing baffle 32, the third noise-absorbing baffle 33, and the fourth noise-absorbing baffle 34. The exhaust holes on the four noise-absorbing baffles and the backpressure baffle 2 are arranged in a circular array. The exhaust holes on the backpressure baffle 2 and the noise-absorbing baffles are both structures consisting of a plate 42 with a protrusion 43. The distance between two noise-absorbing baffles is approximately 15 mm, and the depth of the exhaust hole 41 formed by the protrusion 43 and the plate 42 is 8–10 mm. The thickness of the plate 42 is 0.5–1 mm, which allows the exhaust device to maintain an appropriate weight. Excessive thickness would increase the weight of the exhaust device.

[0084] The backpressure baffle 2 has a curved surface protruding towards the first silencing baffle 31. The first silencing baffle 31 also has a curved surface protruding towards the backpressure baffle 2. The second silencing baffle 32 also has a curved surface protruding towards the backpressure baffle 2 and is mirror-symmetrical to it. The subsequent silencing baffles have the same structure. The structure of the silencing baffles is the same as that of the backpressure baffle 2, which facilitates manufacturing and replacement. The exhaust pipe 15 located at the rear end extends into the last silencing baffle.

[0085] Example 2

[0086] Please see Figure 2 The difference between Embodiment 2 and Embodiment 1 is that the number of sound-absorbing baffles is different, the orientation of the curved surface is different, and the structure of the exhaust port 41 is different.

[0087] Along the direction from the air inlet 11 to the exhaust outlet 12, there are five noise-absorbing baffles, namely the first noise-absorbing baffle 31, the second noise-absorbing baffle 32, the third noise-absorbing baffle 33, the fourth noise-absorbing baffle 34, and the fifth noise-absorbing baffle 35. The exhaust through-hole array on the five noise-absorbing baffles and the back pressure baffle 2 is in a circular array. The noise-absorbing baffles are not curved surfaces that bulge towards the back pressure baffle 2, but rather curved surfaces that bulge towards the inner wall 17 of the rear end of the pipe body. This structure can shorten the length of the exhaust device.

[0088] The exhaust holes 41 of both the back pressure baffle 2 and the sound-absorbing baffle are through holes that penetrate both sides of the baffle. The exhaust holes can be formed by stamping the baffle so that the stamped part is completely detached, or they can be formed by cutting the baffle. The thickness of the baffle is 0.5 to 1 mm, which can control the weight of the exhaust device within an appropriate range.

[0089] Example 3

[0090] Please see Figure 8 and Figure 9 The difference between Embodiment 3 and Embodiment 2 lies in the structure of the exhaust port 41. Specifically, the perforated plate 5 on the backpressure baffle 2 and / or the noise-absorbing baffle is bent towards the rear end of the pipe body 1, so that the exhaust port 41 is formed at the original position of the perforated plate 5 on the backpressure baffle 2 and / or the noise-absorbing baffle. The perforated plate 5 is connected to the backpressure baffle 2 and / or the noise-absorbing baffle via a connecting part 51. The perforated plate 5 was originally part of the baffle; it can be bent towards the rear end or front end of the pipe body 1 through a stamping or cutting process, thereby forming the exhaust port 41 at that position.

[0091] This embodiment also provides a two-stroke internal combustion engine exhaust device, which is the exhaust device described in any of the above embodiments, and the structure of the exhaust device is as follows: Figures 1 to 12As shown. This device is installed on a two-stroke internal combustion engine via a special connecting accessory, connecting the exhaust device's intake port to the engine's exhaust port. This achieves effective exhaust while providing reasonable back pressure control for the engine, significantly reducing operating noise, and improving the drone's environmental adaptability and user experience in various application scenarios.

[0092] This embodiment also provides a drone, including a two-stroke internal combustion engine exhaust device as described in any of the above embodiments, the structure of which is as follows: Figures 1 to 12 As shown. An unmanned aerial vehicle (UAV) is an aircraft that flies without a pilot, controlled by a remote or autonomous flight control system. It can carry various payloads (such as cameras, cargo, water pipes, etc.) and can automatically return to its home base or be guided to land by ground control personnel after completing a specific mission.

[0093] Those skilled in the art should understand that although the exhaust device described in this application is illustrated with an example of a drone, its applicability is not limited to drones. This exhaust device can also be widely used in other power equipment equipped with two-stroke internal combustion engines, such as lawnmowers, motorboats, and ATVs. By reasonably adjusting the structural parameters and installation method, this device can effectively reduce engine exhaust noise and optimize back pressure control, thereby improving the operational stability and environmental adaptability of the equipment.

[0094] Finally, it should be noted that although the above embodiments have been described in the text and drawings of this application, this should not limit the scope of patent protection of this application. Any technical solutions that are based on the essential concept of this application and utilize the content described in the text and drawings of this application, resulting in equivalent structural or procedural substitutions or modifications, as well as the direct or indirect application of the technical solutions of the above embodiments to other related technical fields, are all included within the scope of patent protection of this application.

Claims

1. A two-stroke internal combustion engine, characterized in that The device includes a cylinder and an exhaust device, wherein the exhaust device is directly or indirectly connected to the exhaust port of the cylinder, and the exhaust device includes a pipe body, wherein an air inlet, a baffle group and an exhaust port are sequentially arranged in the exhaust direction within the pipe body. The air intake is directly or indirectly connected to the exhaust port of the cylinder of the two-stroke internal combustion engine. The baffle assembly includes a backpressure baffle and a silencer baffle assembly arranged sequentially along the exhaust direction. The space between the backpressure baffle and the inner wall of the rear end of the pipe body forms a silencer chamber. The rear end of the pipe body is the end of the pipe body near the exhaust port of the exhaust device. Both the backpressure baffle and the silencer baffle assembly are provided with an array of exhaust through holes. The space between the backpressure baffle and the inner wall of the front end of the pipe body forms a backpressure chamber. The front end of the pipe body is the end of the pipe body near the air inlet. The volume of the backpressure chamber is a, and the displacement of the cylinder connected to the backpressure chamber in the two-stroke internal combustion engine is b, where the value of a is 15 to 25 times the value of b.

2. The two-stroke internal combustion engine according to claim 1, characterized in that: The volume 'a' of the back pressure chamber is 1.6–2.6 L; or, The volume 'a' of the back pressure chamber is 2.5 to 4.2 L.

3. The two-stroke internal combustion engine according to claim 1, characterized in that: The back pressure baffle is a curved surface that bulges out toward the sound-absorbing baffle assembly.

4. The two-stroke internal combustion engine according to claim 3, characterized in that: The sound-absorbing baffle assembly includes two or more sound-absorbing baffles. The back pressure baffle and the second sound-absorbing baffle are structurally mirror images of each other. The second sound-absorbing baffle is the one closest to the first sound-absorbing baffle in the sound-absorbing baffle assembly, and the first sound-absorbing baffle is the one closest to the back pressure baffle in the sound-absorbing baffle assembly.

5. The two-stroke internal combustion engine of claim 1, characterized by: The sound-absorbing baffle assembly includes two or more sound-absorbing baffles. The first sound-absorbing baffle is a curved surface that protrudes towards the back pressure baffle. The first sound-absorbing baffle is the one closest to the back pressure baffle in the sound-absorbing baffle assembly.

6. The two-stroke internal combustion engine of claim 1, characterized by: The inner wall of the front end of the tube is a curved surface that bulges towards the air inlet.

7. The two-stroke internal combustion engine of claim 1, characterized by: The exhaust port of the exhaust device is located on the exhaust pipe, and the exhaust pipe extends into the silencer chamber from the rear end of the pipe body.

8. The two-stroke internal combustion engine of claim 1, characterized by: The sound-absorbing baffle assembly includes two or more sound-absorbing baffles. The back pressure baffle and / or the sound-absorbing baffle includes a plate body and multiple protrusions. The plate body has a first vent hole, and the protrusions have second vent holes. The protrusions are fixed to the plate body, and the second vent hole communicates with the first vent hole to form a venting through hole. One first vent hole corresponds to one protrusion; or... The exhaust vents located on the back pressure baffle and / or the sound-absorbing baffle are formed by stamping the back pressure baffle and / or the sound-absorbing baffle; or, The perforated plates on the back pressure baffle and / or the sound-absorbing baffle are bent toward the rear or front end of the pipe body, so that the original position of the back pressure baffle and / or the sound-absorbing baffle corresponding to the perforated plates forms the exhaust passage. The outer edge of the perforated plate is adapted to the inner edge of the exhaust passage, and the perforated plate is connected to the back pressure baffle and / or the sound-absorbing baffle through a connecting part.

9. An exhaust system for a two-stroke internal combustion engine, characterised in that The exhaust device is the exhaust device of the two-stroke internal combustion engine as described in any one of claims 1 to 8.

10. A drone, characterized in that, Including the two-stroke internal combustion engine as described in any one of claims 1 to 8.

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