Aviation piston engine silencer

Abstract

The invention provides an aviation piston engine silencer. The aviation piston engine silencer comprises a cavity with a containing space; the first exhaust pipeline and the second exhaust pipeline are located in the cavity, and a plurality of first holes are formed in the first exhaust pipeline; a plurality of second holes are formed in the second exhaust pipeline; the first exhaust pipeline is connected with a first cylinder body exhaust port of the aviation piston engine, and the second exhaust pipeline is connected with a second cylinder body exhaust port of the aviation piston engine; the first exhaust pipeline and the second exhaust pipeline are symmetrically arranged; the first exhaust tail pipe is positioned at the first end part of the cavity; the second exhaust tail pipe is positioned at the second end part of the cavity; wherein at least one partition plate is arranged in the cavity; the first exhaust pipeline penetrates through at least one partition plate and is communicated with the first exhaust tail pipe; the second exhaust pipeline penetrates through at least one partition plate to be communicated with the second exhaust tail pipe. According to the scheme, the noise reduction effect, the space utilization rate, the structural stability and the layout convenience of the aviation piston engine can be improved.

Description

Technical Field

[0001] The invention relates to the technical field of engine noise reduction processing, in particular to an aviation piston engine muffler. Background Art

[0002] In the field of UAV technology, two-stroke aviation piston engines are widely used for their high power density, simple structure and good high-altitude performance. The exhaust noise of the engine can be divided into two aspects: pulsation noise and airflow noise. The former is the sound of exhaust after high-pressure combustion in the cylinder. It is a periodic noise related to the engine speed and the number of cylinders, and belongs to the low-frequency noise range; while the latter is a general term for fluid noise such as turbulent noise and jet sound that occurs when exhaust flows in the exhaust system. It belongs to wide-band high-frequency noise. When the engine speed is low, pulsation noise is the main noise, and as the speed increases, airflow noise gradually becomes the main noise. Compared with four-stroke engines, the exhaust airflow speed of two-stroke engines is faster and the exhaust energy is greater, so the noise generated is also greater.

[0003] UAVs have very high requirements for the overall layout of the engine, and light weight and compact structure are basic requirements. Most traditional horizontally opposed twin-cylinder two-stroke engines use dual silencers for noise reduction. The dual silencers are large in size and installed in a cantilever beam structure. The structural reliability is low and does not meet the compact layout requirements of UAVs. This type of silencer is mostly a single reactive silencer or a resistive silencer; another commonly used silencer is that the two exhaust ports of the engine share a chamber, but the silencer is internally silenced in the silencer and discharged from one outlet. Although this silencer has a compact structure, the two cylinders of the two-stroke engine exhaust at the same time and share a chamber, which will cause exhaust collision, reduce exhaust energy, increase exhaust back pressure, and lead to a decrease in exhaust rate, a decrease in combustion efficiency, and a deterioration in engine power performance.

[0004] The reactive muffler consists of an exhaust pipe and several partition chambers of different lengths connected to it. The changes in the exhaust pipe section and the size of the partition chamber, the change in the exhaust gas flow direction, and the resonance chamber formed by the exhaust pipe and the partition chamber can effectively reduce noise, especially low-frequency noise. The more partition chambers there are, the better the muffler effect. However, this type of muffler will cause higher exhaust back pressure, greater power loss, and greater mass. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide an aviation piston engine muffler, which can improve the noise reduction effect, space utilization, structural stability and layout convenience of the aviation piston engine.

[0006] In order to solve the above technical problems, the technical solution of the present invention is as follows:

[0007] An aviation piston engine muffler, comprising:

[0008] A cavity having an accommodating space;

[0009] A first exhaust pipeline and a second exhaust pipeline are located inside the cavity, wherein the first exhaust pipeline is provided with a plurality of first holes; and the second exhaust pipeline is provided with a plurality of second holes;

[0010] The first exhaust pipeline is connected to the exhaust port of the first cylinder of the aviation piston engine, and the second exhaust pipeline is connected to the exhaust port of the second cylinder of the aviation piston engine; the first exhaust pipeline and the second exhaust pipeline are symmetrically arranged;

[0011] a first exhaust tail pipe located at a first end of the cavity;

[0012] a second exhaust tail pipe located at a second end of the cavity;

[0013] Wherein, at least one partition is arranged in the cavity, the first exhaust tail pipe is arranged corresponding to the gas outlet of the first exhaust pipeline, and the second exhaust tail pipe is arranged corresponding to the gas outlet of the second exhaust pipeline;

[0014] The first exhaust pipeline is connected to the first exhaust tail pipe through the at least one partition;

[0015] The second exhaust pipe passes through the at least one partition plate and is in communication with the second exhaust tail pipe.

[0016] Optionally, the cavity comprises:

[0017] a first chamber located at a first end of the cavity and connected to a first exhaust tail pipe;

[0018] a second chamber connected to the first chamber via a first partition;

[0019] a third chamber connected to the second chamber via a second partition;

[0020] a fourth chamber connected to the third chamber via a third partition;

[0021] a fifth chamber connected to the fourth chamber via a fourth partition;

[0022] a sixth chamber connected to the fifth chamber via a fifth partition, the sixth chamber being located at a second end of the chamber and being in communication with the second exhaust tail pipe;

[0023] The first exhaust pipeline passes through the fifth chamber, the fourth partition, the fourth chamber, the third partition, the third chamber, the second partition, the second chamber, the first partition, the first chamber, and is connected to the first exhaust tail pipe;

[0024] The second exhaust pipeline passes through the second chamber, the second partition, the third chamber, the third partition, the fourth chamber, the fourth partition, the fifth chamber, the fifth partition, and the sixth chamber to be connected with the second exhaust tail pipe.

[0025] Optionally, the widths of the first chamber and the sixth chamber are both first preset values;

[0026] The widths of the second chamber and the fifth chamber are both second preset values;

[0027] The widths of the third chamber and the fourth chamber are both third preset values;

[0028] The third preset value is a first preset multiple of the second preset value.

[0029] Optionally, the air inlet of the first exhaust pipeline is provided with a first flange, and is connected to the exhaust port of the first cylinder block of the aviation piston engine through the first flange.

[0030] Optionally, the first exhaust pipeline located in the fourth chamber is provided with a first hole belt, and the ratio of the number of holes in the first hole belt is greater than a first preset ratio;

[0031] The first exhaust pipe in the second chamber is provided with a second hole belt, and the ratio of the number of holes in the second hole belt is greater than a second preset ratio;

[0032] Wherein, the second chamber is filled with sound-absorbing material.

[0033] Optionally, the distance between the second hole belt and the second partition is a first preset distance, and the distance between the second hole belt and the first partition is a second preset distance;

[0034] The first preset distance is a second preset multiple of the width of the second chamber; and the second preset distance is a third preset multiple of the width of the second chamber.

[0035] Optionally, the air inlet of the second exhaust pipeline is provided with a second flange, and is connected to the exhaust port of the second cylinder block of the aviation piston engine via the second flange.

[0036] Optionally, the second exhaust pipeline located in the third chamber is provided with a third hole band, and the ratio of the number of holes in the third hole band is greater than the first preset ratio; the second exhaust pipeline located in the fifth chamber is provided with a fourth hole band, and the ratio of the number of holes in the fourth hole band is greater than the second preset ratio; wherein the fifth chamber is filled with sound-absorbing material.

[0037] Optionally, the distance between the fourth hole band and the fourth partition plate is the third preset distance, and the distance between the fourth hole band and the fifth partition plate is the fourth preset distance; wherein the third preset distance is the second preset multiple of the width of the fifth chamber; and the fourth preset distance is the third preset multiple of the width of the fifth chamber.

[0038] Optionally, a gap is left between the gas outlet of the first exhaust pipeline and the first end of the cavity, and a gap is left between the gas outlet of the second exhaust pipeline and the second end of the cavity.

[0039] The above technical solution of the present invention has at least the following technical effects:

[0040] The above-mentioned aviation piston engine silencer of the present invention comprises: a cavity with a accommodating space; a first exhaust pipeline and a second exhaust pipeline located inside the cavity, wherein a plurality of first holes are arranged on the first exhaust pipeline; a plurality of second holes are arranged on the second exhaust pipeline; the first exhaust pipeline is connected to the exhaust port of the first cylinder of the aviation piston engine, and the second exhaust pipeline is connected to the exhaust port of the second cylinder of the aviation piston engine; the first exhaust pipeline and the second exhaust pipeline are symmetrically arranged; a first exhaust tail pipe located at the first end of the cavity; a second exhaust tail pipe located at the second end of the cavity; wherein at least one partition is arranged in the cavity, the first exhaust tail pipe is arranged correspondingly to the air outlet of the first exhaust pipeline, and the second exhaust tail pipe is arranged correspondingly to the air outlet of the second exhaust pipeline; the first exhaust pipeline is connected to the first exhaust tail pipe through the at least one partition; the second exhaust pipeline is connected to the second exhaust tail pipe through the at least one partition. The aviation piston engine silencer of the present invention can improve the noise reduction effect, space utilization, structural stability and layout convenience of the aviation piston engine. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 is a side sectional view of an aviation piston engine muffler of the present invention;

[0042] Figure 2 is a top sectional view of an aviation piston engine muffler of the present invention;

[0043] Figure 3 It is a schematic diagram of the appearance of the aviation piston engine muffler of the present invention.

[0044] Description of reference numerals:

[0045] 1-first flange; 2-second flange; 3-first exhaust pipeline; 31-first hole belt; 32-second hole belt; 4-second exhaust pipeline; 41-third hole belt; 42-fourth hole belt; 5-cavity; 6-first chamber; 7-second chamber; 8-third chamber; 9-fourth chamber; 10-fifth chamber; 11-sixth chamber; 121-first partition; 122-second partition; 123-third partition; 124-fourth partition; 125-fifth partition; 13-first exhaust tail pipe; 14-second exhaust tail pipe. DETAILED DESCRIPTION

[0046] The exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present invention and to enable the scope of the present invention to be fully communicated to those skilled in the art.

[0047] like Figure 1 , Figure 2 As shown, an embodiment of the present invention provides an aviation piston engine muffler, comprising: a cavity 5 having an accommodating space;

[0048] A first exhaust pipeline 3 and a second exhaust pipeline 4 are located inside the cavity 5, wherein the first exhaust pipeline 3 is provided with a plurality of first holes; and the second exhaust pipeline 4 is provided with a plurality of second holes;

[0049] The first exhaust pipeline 3 is connected to the exhaust port of the first cylinder of the aviation piston engine, and the second exhaust pipeline 4 is connected to the exhaust port of the second cylinder of the aviation piston engine; the first exhaust pipeline 3 and the second exhaust pipeline 4 are symmetrically arranged;

[0050] A first exhaust tail pipe 13 located at a first end of the cavity 5;

[0051] A second exhaust tail pipe 14 located at a second end of the cavity 5;

[0052] Among them, at least one partition is arranged in the cavity 5, the first exhaust tail pipe 13 is arranged corresponding to the outlet of the first exhaust pipeline 3, and the second exhaust tail pipe 14 is arranged corresponding to the outlet of the second exhaust pipeline 4; the first exhaust pipeline 3 is connected to the first exhaust tail pipe 13 through the at least one partition; the second exhaust pipeline 4 is connected to the second exhaust tail pipe 14 through the at least one partition.

[0053] In this embodiment, Figure 1As shown, the main body of the aircraft piston engine muffler is a cavity 5, the main bodies of the first exhaust pipeline 3 and the second exhaust pipeline 4 are located inside the cavity 5, and the air inlets of the first exhaust pipeline 3 and the second exhaust pipeline 4 are located outside the cavity 5, which are used to connect with the air outlet of the aircraft piston engine; holes are provided on the first exhaust pipeline 3 and the second exhaust pipeline 4 to reduce noise; at least one partition is provided inside the cavity 5 to divide the cavity 5 into a plurality of chambers to enhance the noise reduction effect; at the first end of the cavity 5, a gas outlet corresponding to the first exhaust pipeline 3 is provided. A first exhaust tail pipe 13 is arranged at a position, and a second exhaust tail pipe 14 is arranged at a position corresponding to the air outlet of the second exhaust pipe 4 at the second end of the cavity 5, and the two exhaust tail pipes discharge the gas respectively; the first exhaust pipe 3 is connected with the first exhaust tail pipe 13 through the at least one partition; the second exhaust pipe 4 is connected with the second exhaust tail pipe 14 through the at least one partition; the solution of the present invention uses two sets of silencer pipes, which are arranged in a large cavity by setting pipes and partitions, so as to realize the function of sharing a cavity and independent silencer.

[0054] like Figure 1 As shown, in an optional embodiment of the present invention, the cavity 5 includes:

[0055] a first chamber 6 located at a first end of the cavity 5 and communicating with the first exhaust tail pipe 13;

[0056] a second chamber 7 connected to the first chamber 6 via a first partition 121;

[0057] a third chamber 8 connected to the second chamber 7 via a second partition 122;

[0058] A fourth chamber 9 connected to the third chamber 8 via a third partition 123;

[0059] a fifth chamber 10 connected to the fourth chamber 9 via a fourth partition 124;

[0060] a sixth chamber 11 connected to the fifth chamber 10 via a fifth partition 125 , the sixth chamber 11 being located at a second end of the chamber 5 and communicating with the second exhaust tail pipe 14 ;

[0061] The first exhaust pipeline 3 passes through the fifth chamber 10, the fourth partition 124, the fourth chamber 9, the third partition 123, the third chamber 8, the second partition 122, the second chamber 7, the first partition 121, the first chamber 6 and communicates with the first exhaust tail pipe 13;

[0062] The second exhaust pipeline 4 passes through the second chamber 7 , the second partition 122 , the third chamber 8 , the third partition 123 , the fourth chamber 9 , the fourth partition 124 , the fifth chamber 10 , the fifth partition 125 , and the sixth chamber 11 to communicate with the second exhaust tail pipe 14 .

[0063] In this embodiment, Figure 1 As shown, a first partition plate 121, a second partition plate 122, a third partition plate 123, a fourth partition plate 124, and a fifth partition plate 125 are arranged inside the cavity 5 to divide the internal space of the cavity 5 into a first chamber 6, a second chamber 7, a third chamber 8, a fourth chamber 9, a fifth chamber 10, and a sixth chamber 11, and each chamber is arranged adjacent to each other, wherein the first chamber 6 is located at the first end of the cavity 5, and the sixth chamber 11 is located at the second end of the cavity 5; an air inlet of the first exhaust pipeline 3 is arranged on the outside of the fifth chamber 10, and the first exhaust pipeline 3 enters the cavity 5 through the opening at the fifth chamber 10, and then passes through the fifth chamber 10, the fourth partition plate 124, the fourth chamber 9, the third partition plate 123, the third chamber 8, the second partition plate 122, the second chamber 7, the first partition plate 12 1. The first chamber 6 is connected to the first exhaust tail pipe 13, and the air outlet of the first exhaust pipeline 3 is located inside the first chamber 6; the air inlet of the second exhaust pipeline 4 is arranged on the outside of the second chamber 7, and the second exhaust pipeline 4 enters the cavity 5 through the opening at the second chamber 7, and then passes through the second chamber 7, the second partition 122, the third chamber 8, the third partition 123, the fourth chamber 9, the fourth partition 124, the fifth chamber 10, the fifth partition 125, and the sixth chamber 11 in sequence to connect with the second exhaust tail pipe 14, and the air outlet of the second exhaust pipeline 4 is located inside the sixth chamber 11; when the sound wave propagates along the pipeline to the chamber, the sudden change of the cross-sectional area will cause the sound wave impedance characteristics to change, and the sound wave can be reflected in the chamber until it disappears, thereby enhancing the noise reduction effect.

[0064] like Figure 1 As shown, in an optional embodiment of the present invention, the widths of the first chamber 6 and the sixth chamber 11 are both first preset values;

[0065] The widths of the second chamber 7 and the fifth chamber 10 are both second preset values;

[0066] The widths of the third chamber 8 and the fourth chamber 9 are both third preset values;

[0067] The third preset value is a first preset multiple of the second preset value.

[0068] In this embodiment, Figure 1As shown, by adjusting the positions of each partition, the first chamber 6 and the sixth chamber 11 are set to the same width, and both are the first preset value; the second chamber 7 and the fifth chamber 10 are set to the same width, and both are the second preset value; the third chamber 8 and the fourth chamber 9 are set to the same width, and both are the third preset value; the first chamber 6, the second chamber 7, the third chamber 8 and the sixth chamber 11, the fifth chamber 10, and the fourth chamber 9 are symmetrically distributed in the cavity 5, and the width and volume of each symmetrical chamber are the same; wherein the third preset value is the first preset multiple of the second preset value, and preferably, the first preset multiple is 1.5 times.

[0069] like Figure 3 As shown, in an optional embodiment of the present invention, the air inlet of the first exhaust pipe 3 is provided with a first flange 1, which is connected to the exhaust port of the first cylinder block of the aviation piston engine through the first flange 1.

[0070] In this embodiment, Figure 3 As shown, a first flange 1 is provided at the air inlet of the first exhaust pipe 3 for fixed connection with the cylinder block of an aviation piston engine. The first flange 1 is coplanarly mounted on the exhaust port of the engine cylinder block by bolts, and the flange mounting method is adopted to avoid the cantilever mounting method, making the muffler installation simpler and more reliable.

[0071] like Figure 1 As shown, in an optional embodiment of the present invention, the first exhaust pipe 3 located in the fourth chamber 9 is provided with a first hole belt 31, and the ratio of the number of holes in the first hole belt 31 is greater than a first preset ratio;

[0072] The first exhaust pipe 3 in the second chamber 7 is provided with a second hole belt 32, and the ratio of the number of holes in the second hole belt 32 is greater than a second preset ratio;

[0073] The second chamber 7 is filled with sound-absorbing material.

[0074] In this embodiment, Figure 1As shown, the first exhaust pipeline 3 is in a sealed state at the portion passing through the fifth chamber 10, and a first hole belt 31 is provided on the pipeline located in the fourth chamber 9, and the first hole belt 31 is provided with evenly distributed holes. The first exhaust pipeline 3 is ventilated with the space of the fourth chamber 9 through the holes on the first hole belt 31, and the number of holes in the first hole belt 31 is greater than the first preset ratio. Preferably, the first preset ratio is 80%. A perforation rate greater than 80% can reduce the local resistance caused by airflow expansion and reduce the exhaust back pressure; the first exhaust pipeline 3 is provided with a first hole belt 31 on the pipeline located in the second chamber 7. The second hole belt 32 is provided with evenly distributed holes, the first exhaust pipe 3 is ventilated with the space of the second chamber 7 through the holes on the second hole belt 32, the ratio of the number of holes in the second hole belt 32 is greater than the second preset ratio, preferably, the second preset ratio is 30%; the first exhaust pipe 3 is filled with a sound-absorbing material in the second chamber 7, and the sound-absorbing material is used to absorb noise; preferably, the sound-absorbing material is a long-fiber sound-absorbing material with a density of 120-150g / L, and the long-fiber sound-absorbing material has a wide sound absorption frequency and can absorb 60Hz-3000Hz noise.

[0075] like Figure 1 As shown, in an optional embodiment of the present invention, the distance between the second hole belt 32 and the second partition plate 122 is a first preset distance, and the distance between the second hole belt 32 and the first partition plate 121 is a second preset distance;

[0076] The first preset distance is a second preset multiple of the width of the second chamber 7 ; the second preset distance is a third preset multiple of the width of the second chamber 7 .

[0077] In this embodiment, Figure 1 As shown, the second hole band 32 is set at a suitable position in the second chamber 7, the distance between the edge of the second hole band 32 and the second partition 122 is a first preset distance, the distance between the second hole band 32 and the first partition 121 is a second preset distance, the first preset distance and the second preset distance are both preset values, the first preset distance is a second preset multiple of the width of the second chamber 7, and the second preset distance is a third preset multiple of the width of the second chamber 7. Preferably, the second preset multiple is 0.5, and the third preset multiple is 0.25, that is to say, the first preset distance is preferably 0.5 times the width of the second chamber 7, and the second preset distance is preferably 0.25 times the width of the second chamber 7; setting the second preset multiple to 0.5 can eliminate the passing frequencies of odd multiples of 1 / 2 wavelength, and setting the third preset multiple to 0.25 can eliminate the passing frequencies of even multiples of 1 / 2 wavelength, thereby improving the noise reduction effect.

[0078] like Figure 3As shown, in an optional embodiment of the present invention, the air inlet of the second exhaust pipe 4 is provided with a second flange 2, which is connected to the exhaust port of the second cylinder block of the aviation piston engine through the second flange 2.

[0079] In this embodiment, Figure 3 As shown, a second flange 2 is provided at the air inlet of the second exhaust pipe 4 for fixed connection with the cylinder block of the aviation piston engine. The first flange 2 is coplanarly installed on the exhaust port of the engine cylinder block by bolts. The flange installation method is adopted to avoid the cantilever installation method, making the muffler installation simpler and more reliable.

[0080] like Figure 1 As shown, in an optional embodiment of the present invention, the second exhaust pipe 4 located in the third chamber 8 is provided with a third hole band 41, and the ratio of the number of holes in the third hole band 41 is greater than the first preset ratio; the second exhaust pipe 4 located in the fifth chamber 10 is provided with a fourth hole band 42, and the ratio of the number of holes in the fourth hole band 42 is greater than the second preset ratio; wherein the fifth chamber 10 is filled with sound-absorbing material.

[0081] In this embodiment, Figure 1 As shown, the second exhaust pipeline 4 is in a sealed state at the portion passing through the second chamber 7, and a third hole belt 41 is provided on the pipeline located in the third chamber 8, and the third hole belt 41 is provided with evenly distributed holes. The second exhaust pipeline 4 is ventilated with the space of the third chamber 8 through the holes on the third hole belt 41, and the number of holes in the third hole belt 41 is greater than the first preset ratio. Preferably, the first preset ratio is 80%. A perforation rate greater than 80% can reduce the local resistance caused by airflow expansion and reduce the exhaust back pressure; the second exhaust pipeline 4 is provided with a third hole belt 41 on the pipeline located in the fifth chamber 10. The fourth hole belt 42 is provided with evenly distributed holes, the second exhaust pipe 4 is ventilated with the space of the fifth chamber 10 through the holes on the fourth hole belt 42, and the ratio of the number of holes in the fourth hole belt 42 is greater than the second preset ratio, preferably, the second preset ratio is 30%; the fifth chamber 10 is filled with a sound-absorbing material around the second exhaust pipe 4, and the sound-absorbing material is used to absorb noise; preferably, the sound-absorbing material is a long-fiber sound-absorbing material with a density of 120-150g / L, and the long-fiber sound-absorbing material has a wide sound absorption frequency and can absorb 60Hz-3000Hz noise.

[0082] like Figure 1As shown, in an optional embodiment of the present invention, the distance between the fourth hole band 42 and the fourth partition plate 124 is the third preset distance, and the distance between the fourth hole band 42 and the fifth partition plate 125 is the fourth preset distance; wherein, the third preset distance is the second preset multiple of the width of the fifth chamber 10; and the fourth preset distance is the third preset multiple of the width of the fifth chamber 10.

[0083] In this embodiment, Figure 1 As shown, the fourth hole band 42 is set at a suitable position in the fifth chamber 10, the distance between the edge of the fourth hole band 42 and the fourth partition 124 is the third preset distance, the distance between the fourth hole band 42 and the fifth partition 125 is the fourth preset distance, the third preset distance and the fourth preset distance are both preset values, the third preset distance is the second preset multiple of the width of the fifth chamber 10, and the fourth preset distance is the third preset multiple of the width of the fifth chamber 10. Preferably, the second preset multiple is 0.5, and the third preset multiple is 0.25, that is to say, the third preset distance is preferably 0.5 times the width of the fifth chamber 10, and the fourth preset distance is preferably 0.25 times the width of the fifth chamber 10; setting the second preset multiple to 0.5 can eliminate the passing frequencies of odd multiples of 1 / 2 wavelength, and setting the third preset multiple to 0.25 can eliminate the passing frequencies of even multiples of 1 / 2 wavelength, thereby improving the noise reduction effect.

[0084] like Figure 1 As shown, in an optional embodiment of the present invention, a gap is left between the air outlet of the first exhaust pipe 3 and the first end of the cavity 5, and a gap is left between the air outlet of the second exhaust pipe 4 and the second end of the cavity 5.

[0085] In this embodiment, Figure 1 As shown, the air outlet of the first exhaust pipeline 3 is located inside the first chamber 6 of the cavity 5, and the air outlet is close to the first end of the cavity 5, with a gap between the air outlet and the first end of the cavity 5. Preferably, the gap size is 5mm-8mm, and the reserved gap can form a Helmholtz chamber inside the first chamber 6 for resonance and silencing again, and finally be discharged through the first exhaust tail pipe 13; the air outlet of the second exhaust pipeline 4 is located inside the sixth chamber 11 of the cavity 5, and the air outlet is close to the second end of the cavity 5, with a gap between the air outlet and the second end of the cavity 5. Preferably, the gap size is 5mm-8mm, and the reserved gap can form a Helmholtz chamber inside the sixth chamber 11 for resonance and silencing again, and finally be discharged through the second exhaust tail pipe 14.

[0086] The scheme of the present invention provides a horizontally opposed twin-cylinder two-stroke aviation piston engine muffler, the muffler is characterized in that two exhaust pipes share a muffler cavity, and pipes and partitions are arranged inside the muffler cavity, so that the exhaust of the two pipes is independent of each other, avoiding the exhaust gas flow collision, and realizing the function of sharing a cavity and independent muffler; the muffler is an impedance composite muffler, which can simultaneously eliminate the low, medium and high frequency noise of the engine exhaust tail sound, has a wide-band muffler function, and has obvious noise reduction effect; at the same time, it has the characteristics of small size, simple structure, and is easy to layout on a twin-cylinder two-stroke engine.

[0087] From the outside, the muffler body of the present invention is a circular cavity, and both ends of the cavity are closed by end covers; the muffler is provided with two mounting flanges and two air inlets; and two exhaust tail pipes are provided at the tail of the muffler;

[0088] The muffler of the present invention is provided with two independent muffler systems. The muffler is divided into a first exhaust pipeline 3 and a second exhaust pipeline 4, and the first exhaust pipeline 3 and the second exhaust pipeline 4 include a flange, an exhaust pipeline, a muffler cavity, a sound absorbing material, and an exhaust tail pipe.

[0089] The muffler cavity, in addition to the left and right end covers, is internally provided with 5 partitions to divide the cavity into 6 chambers; when the sound wave propagates along the pipeline to the chamber, the sudden change in the cross-sectional area will cause the acoustic impedance characteristics to change, and the sound wave will be reflected in the chamber until it disappears;

[0090] The first exhaust pipe 3 runs through five chambers from left to right, and the chambers that play a silencing role are the fourth chamber 9, the second chamber 7, and the first chamber 6; the exhaust pipe in the fourth chamber 9 is provided with a first hole belt 31, and the exhaust pipe in the second chamber 7 is provided with a second hole belt 32, and the perforation rate of the first hole belt 31 is greater than 80%, and the characteristic impedance changes caused by the expansion of the cross-sectional area during the transmission of exhaust sound waves can make most of the sound waves reflect back, thereby reducing the energy of the sound waves passing through, and the chamber silencing method can reduce the low-frequency and medium-frequency sound waves in the noise; the exhaust pipe in the second chamber 7 adopts a silencing method of a porous inner tube, and the perforation rate of the second hole belt 32 is greater than 30%, and is covered with long-fiber sound-absorbing materials, and the noise is absorbed by the attracting material; sufficient perforation rate can reduce the local resistance caused by the sudden change of the interface of the expansion chamber; a 5-8mm gap is set between the first exhaust pipe 3 and the inlet of the first exhaust tail pipe 13 in the first chamber 6, so that the first chamber 6 forms a resonance cavity;

[0091] The silencing working process of the first exhaust pipe 3 is to flow through the fourth chamber 9 for resistive silencing to eliminate part of the low and medium frequency noise, and then pass through the second chamber 7 for resistive composite silencing to eliminate high frequency noise, and finally partially expand again through the first chamber 6, and discharge the muffler through the first exhaust tail pipe 13 to achieve the final silencing effect; specifically, the high-temperature exhaust gas first enters the first exhaust pipe 3 from the first flange 1, and the exhaust gas flows through the fourth chamber 9 for resistive silencing. The first exhaust pipe 3 is provided with honeycomb holes in the fourth chamber 9 section, and the high-temperature and high-speed gas flows through the holes and partially diffuses to the fourth chamber 9. The airflow is reflected in the fourth chamber 9, and the gas flow rate slows down, which can eliminate part of the low and medium frequency noise. ; A perforation rate greater than 80% can reduce the local resistance caused by airflow expansion and reduce exhaust back pressure; the second chamber 7 is paved with long-fiber sound-absorbing material with a density of 120-150g / L, and the first exhaust pipe 3 is provided with holes in the second chamber 7. The exhaust gas flows through the second chamber 7, and part of the airflow expands to the second chamber 7. The noise is absorbed by the sound-absorbing material. The long-fiber sound-absorbing material has a wide sound absorption frequency and can absorb 60Hz-3000Hz noise; the air outlet of the first exhaust pipe 3 is inserted into the first chamber 6, leaving a gap of 5-8mm from the first end of the cavity 5, and a Helmholtz chamber is formed inside the first chamber 6 to resonate and silence again, and finally discharged through the first exhaust tail pipe 13.

[0092] The second exhaust pipe 4 runs through five chambers from right to left, and the chambers that play a silencing role are the third chamber 8, the fifth chamber 10, and the sixth chamber 11; the exhaust pipe in the third chamber 8 is provided with a third hole belt 41, and the exhaust pipe in the fifth chamber 10 is provided with a fourth hole belt 42. The perforation rate of the third hole belt 41 is greater than 80%. The characteristic impedance changes caused by the expansion of the cross-sectional area during the transmission of exhaust sound waves can reflect most of the sound waves back, thereby reducing the energy of the sound waves passing through. The chamber silencing method can reduce low-frequency and medium-frequency sound waves in the noise; the fifth chamber 10 adopts a silencing method of a porous inner tube, the perforation rate of the fourth hole belt 42 is greater than 30%, and is covered with long-fiber sound-absorbing materials, and the noise is absorbed by the attracting material; sufficient perforation rate can reduce the local resistance caused by the sudden change of the interface of the expansion chamber; a 5-8mm gap is set between the second exhaust pipe 4 and the inlet of the second exhaust tail pipe 14 in the sixth chamber 11, so that the sixth chamber 11 forms a resonance cavity;

[0093] The silencing working process of the second exhaust pipe 4 is to flow through the third chamber 8 for resistive silencing to eliminate part of the low and medium frequency noise, and then pass through the fifth chamber 10 for resistive composite silencing to eliminate high frequency noise, and finally partially expand again through the sixth chamber 11, and discharge the muffler through the second exhaust tail pipe 14 to achieve the final silencing effect; specifically, the high-temperature exhaust gas first enters the second exhaust pipe 4 from the second flange 2, and the exhaust gas flows through the third chamber 8 for resistive silencing. The second exhaust pipe 4 is provided with honeycomb holes in the third chamber 8 section. The high-temperature and high-speed gas flows through the holes and partially diffuses to the third chamber 8. The airflow is reflected in the third chamber 8, and the gas flow rate slows down, which can eliminate part of the low and medium frequency noise; large A perforation rate of 80% can reduce the local resistance caused by airflow expansion and reduce exhaust back pressure; the fifth chamber 10 is paved with long-fiber sound-absorbing material with a density of 120-150g / L, and the second exhaust pipe 4 is provided with holes in the fifth chamber 10. The exhaust gas flows through the fifth chamber 10, and part of the airflow expands to the fifth chamber 10. The noise is absorbed by the sound-absorbing material. The long-fiber sound-absorbing material has a wide sound absorption frequency and can absorb 60Hz-3000Hz noise; the air outlet of the second exhaust pipe 4 is inserted into the sixth chamber 11, leaving a gap of 5-8mm from the second end of the cavity 5, and the Helmholtz chamber is formed inside the sixth chamber 11 to resonate and silence again, and finally discharged through the second exhaust tail pipe 14.

[0094] The aviation piston engine silencer described in the above scheme of the present invention is suitable for noise reduction and silencing of horizontally opposed twin-cylinder two-stroke aviation piston engines, and has a small size and light weight; two independent silencing systems are arranged in a silencing cavity, which rationally utilizes the peripheral space of the engine, and the two external flanges are fixedly connected to the engine cylinder body, avoiding the cantilever installation method, and the fixing method is simple and reliable; the impedance composite silencing method is used to widen the silencing frequency range, taking into account low, medium and high frequency silencing; the combination of gas expansion and perforated inner tube reduces the gas flow velocity and energy, reduces the exhaust back pressure, and minimizes the engine power loss.

[0095] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. An aviation piston engine muffler, characterized in that: include: A cavity (5) having an accommodating space; A first exhaust pipeline (3) and a second exhaust pipeline (4) are located inside the cavity (5), wherein the first exhaust pipeline (3) is provided with a plurality of first holes; and the second exhaust pipeline (4) is provided with a plurality of second holes; The first exhaust pipeline (3) is connected to the exhaust port of the first cylinder of the aviation piston engine, and the second exhaust pipeline (4) is connected to the exhaust port of the second cylinder of the aviation piston engine; the first exhaust pipeline (3) and the second exhaust pipeline (4) are symmetrically arranged; a first exhaust tail pipe (13) located at a first end of the cavity (5); a second exhaust tail pipe (14) located at a second end of the cavity (5); Wherein, at least one partition is arranged in the cavity (5), the first exhaust tail pipe (13) is arranged corresponding to the air outlet of the first exhaust pipeline (3), and the second exhaust tail pipe (14) is arranged corresponding to the air outlet of the second exhaust pipeline (4); The first exhaust pipeline (3) passes through the at least one partition plate and is in communication with the first exhaust tail pipe (13); The second exhaust pipe (4) passes through the at least one partition plate and is in communication with the second exhaust tail pipe (14).

2. The aviation piston engine muffler according to claim 1, characterized in that: The cavity (5) comprises: A first chamber (6) located at a first end of the cavity (5) and connected to a first exhaust tail pipe (13); a second chamber (7) connected to the first chamber (6) via a first partition (121); a third chamber (8) connected to the second chamber (7) via a second partition (122); a fourth chamber (9) connected to the third chamber (8) via a third partition plate (123); a fifth chamber (10) connected to the fourth chamber (9) via a fourth partition plate (124); a sixth chamber (11) connected to the fifth chamber (10) via a fifth partition (125), the sixth chamber (11) being located at a second end of the chamber (5) and communicating with the second exhaust tail pipe (14); The first exhaust pipeline (3) passes through the fifth chamber (10), the fourth partition plate (124), the fourth chamber (9), the third partition plate (123), the third chamber (8), the second partition plate (122), the second chamber (7), the first partition plate (121), and the first chamber (6) to communicate with the first exhaust tail pipe (13); The second exhaust pipeline (4) passes through the second chamber (7), the second partition (122), the third chamber (8), the third partition (123), the fourth chamber (9), the fourth partition (124), the fifth chamber (10), the fifth partition (125), and the sixth chamber (11) and is connected to the second exhaust tail pipe (14).

3. The aviation piston engine muffler according to claim 2, characterized in that: The widths of the first chamber (6) and the sixth chamber (11) are both first preset values; The widths of the second chamber (7) and the fifth chamber (10) are both second preset values; The widths of the third chamber (8) and the fourth chamber (9) are both third preset values; The third preset value is a first preset multiple of the second preset value.

4. The aviation piston engine muffler according to claim 3, characterized in that: The air inlet of the first exhaust pipeline (3) is provided with a first flange (1), and is connected to the exhaust port of the first cylinder block of the aviation piston engine via the first flange (1).

5. The aviation piston engine muffler according to claim 4, characterized in that: The first exhaust pipe (3) located in the fourth chamber (9) is provided with a first hole belt (31), and the ratio of the number of holes in the first hole belt (31) is greater than a first preset ratio; The first exhaust pipe (3) located in the second chamber (7) is provided with a second hole belt (32), and the ratio of the number of holes in the second hole belt (32) is greater than a second preset ratio; Wherein, the second chamber (7) is filled with sound-absorbing material.

6. The aviation piston engine muffler according to claim 5, characterized in that: The distance between the second hole belt (32) and the second partition plate (122) is a first preset distance, and the distance between the second hole belt (32) and the first partition plate (121) is a second preset distance; Wherein, the first preset distance is a second preset multiple of the width of the second chamber (7); and the second preset distance is a third preset multiple of the width of the second chamber (7).

7. The aviation piston engine muffler according to claim 6, characterized in that: The air inlet of the second exhaust pipeline (4) is provided with a second flange (2), and is connected to the exhaust port of the second cylinder block of the aviation piston engine via the second flange (2).

8. The aviation piston engine muffler according to claim 7, characterized in that: The second exhaust pipe (4) located in the third chamber (8) is provided with a third hole belt (41), and the ratio of the number of holes in the third hole belt (41) is greater than the first preset ratio; the second exhaust pipe (4) located in the fifth chamber (10) is provided with a fourth hole belt (42), and the ratio of the number of holes in the fourth hole belt (42) is greater than the second preset ratio; wherein the fifth chamber (10) is filled with a sound-absorbing material.

9. The aviation piston engine muffler according to claim 8, characterized in that: The distance between the fourth hole belt (42) and the fourth partition plate (124) is the third preset distance, and the distance between the fourth hole belt (42) and the fifth partition plate (125) is the fourth preset distance; wherein the third preset distance is the second preset multiple of the width of the fifth chamber (10); and the fourth preset distance is the third preset multiple of the width of the fifth chamber (10).

10. The aviation piston engine muffler according to claim 9, characterized in that: A gap is left between the gas outlet of the first exhaust pipeline (3) and the first end of the cavity (5), and a gap is left between the gas outlet of the second exhaust pipeline (4) and the second end of the cavity (5).

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