A diesel engine intake sound muffling and noise reduction device

Abstract

The application provides a diesel engine intake sound elimination and noise reduction device, which comprises a shell, air inlet holes are arranged on the left and right sides of the upper side of the shell, an air outlet hole is arranged on the right side of the bottom of the shell, a first sound elimination channel and a second sound elimination channel are arranged in the shell, a plurality of first sound elimination cavities are arranged from top to bottom between the first sound elimination channel and the second sound elimination channel, a plurality of second sound elimination cavities are arranged from top to bottom on the side, away from the first sound elimination cavities, of the first sound elimination channel and the second sound elimination channel, the first sound elimination channel, the second sound elimination channel, the first sound elimination cavities and the second sound elimination cavities are in communication with each other, sound elimination plates are fixedly connected to the left and right sides of the first sound elimination channel and the second sound elimination channel, the upper side inlet of the first sound elimination channel is connected to the left air inlet hole, the upper side inlet of the second sound elimination channel is connected to the right air inlet hole, the bottom outlets of the first sound elimination channel and the second sound elimination channel are connected and are connected to the air outlet hole. The device has the beneficial effects that the device improves the air intake, prolongs the residence time of sound waves in the device, and effectively eliminates sound and reduces noise.

Description

Technical Field

[0001] This invention belongs to the field of diesel engine muffler equipment, and in particular relates to an intake muffler and noise reduction device for diesel engines. Background Technology

[0002] When a diesel engine is running, air enters the cylinder. Compressed air is used to raise its temperature above the auto-ignition point of diesel fuel. Diesel engines generate considerable noise during operation, and to reduce this noise, a muffler is installed at the intake end. Currently, noise reduction at the intake end is achieved by adding mufflers to both ends of the turbocharger. The muffler structure consists of a cylindrical tube housed within a casing connected to the air pipe. A fixed baffle is fitted onto the outer surface of the tube, and through holes are formed in each area separated by the baffle. While this structure is relatively simple, its small size and relatively standardized internal structure result in poor noise reduction. The short airflow time prevents sound waves from undergoing multi-stage diffraction, reflection, and refraction within the muffler, leading to weak energy attenuation and ultimately affecting the noise reduction effect. Summary of the Invention

[0003] In view of this, the present invention aims to overcome the shortcomings of the above-mentioned problems in the prior art and proposes an intake noise reduction device for diesel engines.

[0004] To achieve the above objectives, the technical solution of the present invention is implemented as follows:

[0005] A diesel engine intake silencing and noise reduction device includes a housing. Air intake holes are provided at opposite ends on the upper left and right sides of the housing, and an air outlet is provided on the bottom right side. Inside the housing, a first silencing channel and a second silencing channel are provided. Multiple first silencing chambers are provided between the first and second silencing channels from top to bottom. Multiple second silencing chambers are provided on the side of the first and second silencing channels away from the first silencing chambers from top to bottom. The first silencing channel, the second silencing channel, the first silencing chamber, and the second silencing chamber are interconnected. Silencing plates are fixed to the left and right sides of both the first and second silencing channels. The upper inlet of the first silencing channel is connected to the left air intake hole, and the upper inlet of the second silencing channel is connected to the right air intake hole. The bottom outlets of the first and second silencing channels are connected and both lead to the air outlet.

[0006] Furthermore, the first silencing channel includes a first upper guide section, a first middle section, and a first lower guide section. The first middle section is vertically arranged and connected to the first upper guide section on its upper side and to the first lower guide section on its lower side. The first upper guide section is connected to the left air inlet. The part of the first upper guide section opposite to the left air inlet is a first inclined section that slopes from top to bottom away from the left air inlet. The part corresponding to the bottom of the left air inlet is a first arc-shaped section. The side of the first lower guide section away from the air outlet is a second arc-shaped section that slopes from top to bottom towards the air outlet. The bottom of the second arc-shaped section is located at the bottom wall of the housing.

[0007] The second silencing channel includes a second upper guide section, a second middle section, and a second lower guide section. The second middle section is vertically arranged and connected to the second upper guide section on its upper side and to the second lower guide section on its lower side. The second upper guide section is connected to the right air intake hole, and the part of the second upper guide section opposite to the right air intake hole is a second inclined section that slopes from top to bottom away from the right air intake hole. The part corresponding to the bottom of the right air intake hole is a third arc-shaped section.

[0008] The first lower guide section is configured with a fourth arc-shaped segment that slopes from top to bottom towards the side closest to the air outlet on the side near the air outlet. The second lower guide section is configured with a fifth arc-shaped segment that slopes from top to bottom towards the side closest to the air outlet on the side away from the air outlet. The bottoms of the fourth and fifth arc-shaped segments are connected by an arc-shaped transition section, and the lowest point of the transition section is higher than the bottom wall of the shell.

[0009] Furthermore, the fourth arc segment, the fifth arc segment, the transition segment, and the bottom of the first silencing cavity at the lowest side form a third silencing cavity.

[0010] Furthermore, the rear side of the second arc-shaped segment and the shell form a fourth silencing cavity. A connecting hole is provided on one side of the lower part of the shell corresponding to the fourth silencing cavity, and a connecting plate is connected at the connecting hole.

[0011] Furthermore, the sound-absorbing plate includes a substrate and a felt layer fixed to one side of the substrate, and the substrate is uniformly provided with multiple through holes.

[0012] Furthermore, the first, second, third, and fourth silencing chambers are all filled with sound-absorbing cotton.

[0013] Furthermore, each of the first silencing cavities has an annular connecting rib located at the circumferential center of its inner wall.

[0014] Furthermore, the housing includes an upper housing and a lower housing fixed to the lower side of the upper housing. The air inlet is located at both ends of the upper side of the upper housing. The first upper guide portion and the first middle portion of the first silencing channel, the second upper guide portion and the second middle portion of the second silencing channel, as well as the first silencing cavity and the second silencing cavity are all located inside the upper housing. The uppermost second silencing cavity is located below the corresponding air inlet. The first lower guide portion of the first silencing channel and the second lower guide portion of the second silencing channel are both located inside the lower housing. The air outlet is located on the lower housing, and the lowermost second silencing cavity on the right side is located below the air outlet.

[0015] Furthermore, the upper shell includes two half-shells fixed together. The bottom of each half-shell is fixed to the upper side of the lower shell, and each half-shell has two spaced and longitudinally arranged semi-silencing channels on one side. Each half-shell has a semi-circular air intake groove at both ends of its upper side. The upper end of each semi-silencing channel is connected to the corresponding air intake groove, and the lower end is open and connected to the lower shell. Between the two semi-silencing channels on one side of each half-shell, there are multiple first semi-silencing cavities distributed from top to bottom. Between the left and right side walls of each half-shell and the adjacent semi-silencing channels, there are multiple second semi-silencing cavities that are connected to the corresponding semi-silencing channels from top to bottom. When the two half-shells are fixed together, the two air intake grooves are joined together to form an air intake hole, the corresponding semi-silencing channels are joined together to form a silencing channel, the corresponding first semi-silencing cavities are joined together to form a first silencing cavity, and the corresponding second semi-silencing cavities are joined together to form a second silencing cavity.

[0016] Furthermore, each half-shell has a first fixed flange protruding outward at the side edges where they meet on the left and right sides, and a second fixed flange protruding upward at the side edges where they meet at the top. After the two half-shells are joined together, the two corresponding first fixed flanges at each end are fixed together by screws, and the second fixed flanges are also fixed together by screws. The bottom of each half-shell is fixed to the upper side of the lower shell by screws. Threaded connection holes are provided on the outer surface of one half-shell at the middle of each of the two adjacent first silencing cavities and at the bottom side wall of the lowest silencing cavity. Threaded blind holes are provided on the other half-shell at the locations corresponding to the threaded connection holes. Each threaded connection hole and the corresponding threaded blind hole are fixed together by screws.

[0017] Furthermore, each half-shell has a reinforcing flange circumferentially provided on the side wall opposite to the second silencing cavity.

[0018] Compared with the prior art, the present invention has the following advantages:

[0019] The diesel engine intake silencing and noise reduction device of the present invention has two interconnected silencing channels in the upper housing and a cavity connected to the silencing channels in the lower housing. An air outlet is provided on one side of the left and right side walls of the cavity. The air inlet and outlet are not in the same vertical direction as the silencing channels, but rather bend and change direction at the air inlet and outlet. When airflow enters the corresponding silencing channels from the air inlets on both sides, the sound waves in the airflow continuously impact the inner wall of the upper housing and the first and second silencing plates, producing diffraction, reflection, and refraction, reducing the amplitude of the sound waves and attenuating their energy, thereby achieving effective silencing and noise reduction. This device increases the intake volume and prolongs the residence time of the sound waves within the device, effectively reducing noise. Attached Figure Description

[0020] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0021] Figure 1 This is a schematic diagram of the structure of the intake muffler and noise reduction device for diesel engines according to an embodiment of the present invention;

[0022] Figure 2 This is a schematic diagram of the internal structure of the intake muffler and noise reduction device for diesel engines according to an embodiment of the present invention;

[0023] Figure 3 This is a schematic diagram of the structure of the diesel engine intake muffler and noise reduction device after removing one half of the housing, as described in an embodiment of the present invention.

[0024] Explanation of reference numerals in the attached figures:

[0025] 1. Upper housing; 101. Air inlet; 102. First fixed flange; 103. Second fixed flange; 104. Threaded connection hole;

[0026] 2. Lower housing; 201. Vent; 202. Connecting hole; 203. Connecting plate;

[0027] 3. First silencing channel; 301. First upper guide section; 3011. First inclined section; 3012. First arc-shaped section; 302. First middle section; 303. First lower guide section; 3031. Second arc-shaped section; 3032. Fourth arc-shaped section;

[0028] 4. Second silencing channel; 401. Second upper guide section; 4011. Second inclined section; 4012. Third arc-shaped section; 402. Second middle section; 403. Second lower guide section; 4031. Fifth arc-shaped section;

[0029] 5. First silencing cavity; 501. Connecting rib;

[0030] 6. Second silencing cavity; 601. Reinforcing convex edge;

[0031] 7. Third silencing chamber; 8. Fourth silencing chamber; 9. Silencer plate. Detailed Implementation

[0032] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0033] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0034] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0035] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0036] As shown in the figure, a diesel engine intake silencing and noise reduction device includes a housing. Intake holes 101 are provided at opposite ends on the upper left and right sides of the housing, and an exhaust hole 201 is provided on the bottom right side. Inside the housing, a first silencing channel 3 and a second silencing channel 4 are provided. Multiple first silencing chambers 5 are provided between the first silencing channel 3 and the second silencing channel 4 from top to bottom. Multiple second silencing chambers 6 are provided on the side of the first silencing channel 3 and the second silencing channel 4 away from the first silencing chambers 5 from top to bottom. The first silencing channel 3, the second silencing channel 4, the first silencing chambers 5, and the second silencing chambers 6 are interconnected. Silencer plates 9 are fixed to the left and right sides of both the first silencing channel 3 and the second silencing channel 4. The upper inlet of the first silencing channel 3 is connected to the left intake hole 101, and the upper inlet of the second silencing channel 4 is connected to the right intake hole 101. The bottom outlets of the first silencing channel 3 and the second silencing channel 4 are connected and both connect to the exhaust hole 201. In this embodiment, the airflow enters the housing from the air inlets 101 on both sides, flows along the first silencing channel 3 and the second silencing channel 4, and diffuses into the first silencing cavity 5 and the second silencing cavity 6. The sound waves in the airflow will continuously impact the inner wall of the housing and the silencing plate 9, producing diffraction, reflection, refraction, etc., reducing the amplitude of the sound waves and attenuating their energy, thereby achieving the effect of effective noise reduction.

[0037] The first silencing channel 3 includes a first upper guide section 301, a first middle section 302, and a first lower guide section 303. The first middle section 302 is vertically arranged and connected to the first upper guide section 301 on its upper side and to the first lower guide section 303 on its lower side. The first upper guide section 301 is connected to the left air inlet 101. The first upper guide section 301 is configured with a first inclined section 3011 that slopes from top to bottom away from the left air inlet 101 at the position opposite to the left air inlet 101. A first arc-shaped section 3012 is configured at the position corresponding to the bottom of the left air inlet 101. The first lower guide section 303 is configured with a second arc-shaped section 3031 that slopes from top to bottom towards the air outlet 201 on the side away from the air outlet 201. The bottom of the second arc-shaped section 3031 is located at the bottom wall of the housing. The second silencing channel 4 includes a second upper guide section 401, a second middle section 402, and a second lower guide section 403. Part 402 is vertically arranged and connected to the second upper guide part 401 on the upper side and the second lower guide part 403 on the lower side. The second upper guide part 401 is connected to the right air inlet 101. The second upper guide part 401 is configured as a second inclined section 4011 that slopes from top to bottom away from the right air inlet 101 at the position opposite to the right air inlet 101. The third arc-shaped section 4012 is configured at the position corresponding to the bottom of the right air inlet 101. The first lower guide part 303 is configured as a fourth arc-shaped section 3032 that slopes from top to bottom towards the side of the air outlet 201 on the side near the air outlet 201. The second lower guide part 403 is configured as a fifth arc-shaped section 4031 that slopes from top to bottom towards the side of the air outlet 201 on the side away from the air outlet 201. The bottom of the fourth arc-shaped section 3032 and the fifth arc-shaped section 4031 are connected together by an arc-shaped transition section, and the lowest point of the transition section is higher than the bottom wall of the shell. In this embodiment, the air inlet 101 is used to connect the air filter. The airflow entering the air inlet 101 is spiral-shaped, which can blow further and effectively reduce air resistance. After the airflow enters the air inlet 101, due to the inclined arrangement of the first inclined section 3011 and the second inclined section 4011, the airflow will collide with the first inclined section 3011 and the second inclined section 4011 for flow guidance, realizing a smooth transition of airflow direction, making the flow smoother, and effectively avoiding the direct impact of the airflow entering from the two air inlets 101, which would reduce the flow rate of the downward airflow. The first arc-shaped section 3012 and the third arc-shaped section 4012 both play a role in smoothing the airflow. The second arc-shaped section 3031 is inclined and intersects the bottom wall of the shell at an obtuse angle. This arrangement is to avoid the airflow vertically impacting the bottom wall of the shell in this area and then vertically returning to form a vacuum zone, thus guiding the airflow. The fourth arc-shaped section 3032, the fifth arc-shaped section 4031 and the transition section also guide the airflow towards the air outlet 201.

[0038] The third silencing cavity 7 is formed between the fourth arc segment 3032, the fifth arc segment 4031, the transition segment and the bottom of the first silencing cavity 5 at the bottom. The third silencing cavity 7 has the same function as the first silencing cavity 5, which is to diffuse the airflow and cause impact, attenuate the amplitude of the sound wave, and thus achieve the effect of silencing and noise reduction.

[0039] The rear side of the second arc segment 3031 and the shell form a fourth silencing cavity 8. The fourth silencing cavity 8 has the same function as the third silencing cavity 7. A connecting hole 202 is provided on one side of the lower part of the shell corresponding to the fourth silencing cavity 8, and a connecting plate 203 is connected at the connecting hole 202.

[0040] The sound-absorbing plate 9 includes a substrate and a felt layer fixed to one side of the substrate. Multiple through holes are uniformly distributed on the substrate. In this embodiment, the substrate is made of aluminum, which has good toughness. The felt layer and the through holes on the substrate at the contact points with the felt layer both have resistive sound-absorbing functions. The other side of the substrate has a resistive sound-absorbing function. The sound-absorbing plate 9 with this structure can effectively improve the sound-absorbing effect. The substrate in each side of the sound-absorbing plate 9 can be a one-piece molded structure or a structure in which multiple substrate units are arranged side-by-side and fixed together.

[0041] The first silencing cavity 5, the second silencing cavity 6, the third silencing cavity 7, and the fourth silencing cavity 8 are all filled with sound-absorbing cotton.

[0042] Each first silencing cavity 5 has an annular connecting rib 501 at the center of the inner sidewall. In this embodiment, the connecting rib 501 serves two purposes: firstly, it works in conjunction with the corresponding silencing plate 9 to allow sound waves in the airflow entering the first silencing cavity 5 to undergo diffraction, reflection, and refraction when they encounter obstacles during propagation, thereby reducing the amplitude and weakening the energy, thus achieving the effect of silencing and noise reduction; secondly, it strengthens the shell.

[0043] The housing includes an upper housing 1 and a lower housing 2 fixed to the lower side of the upper housing 1. The air inlet 101 is located at both ends of the upper side of the upper housing 1. The first upper guide portion 301 and the first middle portion 302 of the first silencing channel 3 and the second upper guide portion 401 and the second middle portion 402 of the second silencing channel 4, as well as the first silencing cavity 5 and the second silencing cavity 6 are all located inside the upper housing 1, and the uppermost second silencing cavity 6 is located below the corresponding air inlet 101. The first lower guide portion 303 of the first silencing channel 3 and the second lower guide portion 403 of the second silencing channel 4 are both located inside the lower housing 2. The air outlet 201 is located on the lower housing 2, and the lowermost second silencing cavity 6 on the right side is located below the air outlet 201.

[0044] The upper shell 1 includes two half-shells fixed together. The bottom of each half-shell is fixed to the upper side of the lower shell 2. Each half-shell has two spaced and longitudinally arranged semi-silencing channels on one side. Each half-shell has a semi-circular air inlet groove at both ends of its upper side. The upper end of each semi-silencing channel is connected to the corresponding air inlet groove, and the lower end is open and connected to the lower shell 2. Multiple first semi-silencing cavities are provided between the two semi-silencing channels on one side of each half-shell. Multiple second semi-silencing cavities connected to the corresponding semi-silencing channels are provided between the left and right side walls of each half-shell and the adjacent semi-silencing channels from top to bottom. When the two half-shells are fixed together, the two air inlets are joined together to form an air inlet 101, the corresponding semi-silencing channels are joined together to form a silencing channel, the corresponding first semi-silencing cavities are joined together to form a first silencing cavity 5, and the corresponding second semi-silencing cavities are joined together to form a second silencing cavity 6.

[0045] Each half-shell has a first fixing flange 102 protruding outward at the opposite side edges on the left and right sides, and a second fixing flange 103 protruding upward at the opposite side edges on the top. After the two half-shells are joined together, the two corresponding first fixing flanges 102 at each end are fixed together by screws, and the second fixing flanges 103 are also fixed together by screws. The bottom of each half-shell is fixed to the upper side of the lower shell 2 by screws. Threaded connection holes 104 are provided on the outer surface of one half-shell at the middle of each two adjacent first silencing cavities 5 and at the bottom side wall of the lowest silencing cavity. Threaded blind holes are provided on the other half-shell at the locations corresponding to the threaded connection holes 104. Each threaded connection hole 104 and the corresponding threaded blind hole are fixed together by screws to strengthen the fixed connection between the two half-shells.

[0046] Each half-shell has a reinforcing flange 601 circumferentially provided on the opposite side wall corresponding to the second silencing cavity 6, to ensure the connection strength of the two mating planes.

[0047] In this embodiment, the sound-absorbing plates 9 are all welded and fixed inside the upper shell 1 or the lower shell 2.

[0048] Both the front and rear sides of the lower housing 2 are provided with flow sensor mounting holes and crankcase exhaust gas connection holes near the air outlet 201. In use, the two sets of flow sensor mounting holes and crankcase exhaust gas connection holes serve as backups for each other.

[0049] The working process of this embodiment is as follows:

[0050] Two air inlets 101 are used to connect to the air filter, and an air outlet 201 is used to connect to the turbocharger. Airflow diffuses from the first silencer channel 3 and the second silencer channel 4 into the first silencer cavity 5, the second silencer cavity 6, the third silencer cavity 7, and the fourth silencer cavity 8. Sound waves are silenced and reduced in noise by the silencer plate 9. Sound waves entering each silencer cavity impact the inner wall of the housing, the connecting ribs 501, and the reinforcing convex edge 601, then return to impact the silencer plate 9. When sound waves encounter obstacles during propagation, diffraction, reflection, and refraction occur, causing the amplitude to decrease and the energy to weaken. The sound waves are then discharged from the air outlet 201, achieving the noise reduction effect. In addition to the silencer plate 9, sound-absorbing cotton further enhances the noise reduction effect. The silenced airflow flows into the turbocharger to participate in diesel engine combustion, thus achieving intake noise reduction during the intake process.

[0051] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A noise reduction device for intake air of a diesel engine, characterized in that: The device includes a housing with air inlets at the left and right ends of the upper side and an air outlet on the right side of the bottom. Inside the housing, there is a first silencing channel and a second silencing channel. Multiple first silencing chambers are arranged between the first and second silencing channels from top to bottom. Multiple second silencing chambers are arranged on the side of the first and second silencing channels away from the first silencing chambers from top to bottom. The first silencing channel, the second silencing channel, the first silencing chamber, and the second silencing chamber are interconnected. Silencing plates are fixed to the left and right sides of the first and second silencing channels. The upper inlet of the first silencing channel is connected to the left air inlet, and the upper inlet of the second silencing channel is connected to the right air inlet. The bottom outlets of the first and second silencing channels are connected and both are connected to the air outlet. The first silencing channel includes a first upper guide section, a first middle section, and a first lower guide section. The first middle section is vertically arranged and connected to the first upper guide section on its upper side and to the first lower guide section on its lower side. The first upper guide section is connected to the left air inlet. The part of the first upper guide section opposite to the left air inlet is a first inclined section that slopes from top to bottom away from the left air inlet. The part corresponding to the bottom of the left air inlet is a first arc-shaped section. The side of the first lower guide section away from the air outlet is a second arc-shaped section that slopes from top to bottom towards the air outlet. The bottom of the second arc-shaped section is located at the bottom wall of the housing. The second silencing channel includes a second upper guide section, a second middle section, and a second lower guide section. The second middle section is vertically arranged and connected to the second upper guide section on its upper side and to the second lower guide section on its lower side. The second upper guide section is connected to the right air intake hole, and the part of the second upper guide section opposite to the right air intake hole is a second inclined section that slopes from top to bottom away from the right air intake hole. The part corresponding to the bottom of the right air intake hole is a third arc-shaped section. The first lower guide section is configured with a fourth arc-shaped segment that slopes from top to bottom towards the side of the air outlet on the side near the air outlet. The second lower guide section is configured with a fifth arc-shaped segment that slopes from top to bottom towards the side of the air outlet on the side away from the air outlet. The bottoms of the fourth and fifth arc-shaped segments are connected by an arc-shaped transition section, and the lowest point of the transition section is higher than the bottom wall of the shell. The third silencing cavity is formed by the fourth arc segment, the fifth arc segment, the transition segment, and the bottom of the first silencing cavity at the bottom.

2. The intake noise reduction device for a diesel engine according to claim 1, characterized in that: The rear side of the second arc-shaped section forms a fourth silencing cavity with the shell.

3. The intake noise reduction device for a diesel engine according to claim 1, characterized in that: The sound-absorbing plate includes a substrate and a felt layer fixed to one side of the substrate. The substrate has multiple through holes evenly distributed on it.

4. The intake noise reduction device for a diesel engine according to claim 2, characterized in that: The first, second, third, and fourth silencing chambers are all filled with sound-absorbing cotton.

5. The intake noise reduction device for a diesel engine according to claim 1, characterized in that: Each of the first silencing chambers has an annular connecting rib located at the center of the circumference of its inner wall.

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