An intake muffler for an automotive engine

Abstract

The application relates to the technical field of silencers, in particular to an air intake silencer for an automobile engine, which comprises a shell, an inner pipe, a noise reduction assembly and a rotational flow adsorption assembly. The inner pipe is coaxially arranged in the shell. The noise reduction assembly is coaxially arranged in the shell and located at the two ends of the inner pipe. The rotational flow adsorption assembly is coaxially arranged in the inner pipe and connected with the shell. When air enters the shell through the air inlet end of the shell, the air first passes through the noise reduction assembly, then passes through the rotational flow adsorption assembly, and finally is discharged from the air outlet end of the shell. When the air flows in the shell, the rotational flow adsorption assembly is driven to rotate. The inner pipe, the noise reduction assembly and the rotational flow assembly can generate heat by friction on the basis of reducing the noise of the airflow, convert part of the kinetic energy of the airflow into heat energy, and thus improve the driving experience on the basis of reducing the surge noise.

Description

Technical Field

[0001] This invention relates to the field of muffler technology, specifically to an intake muffler for automobile engines. Background Technology

[0002] In the field of automotive engineering, noise, vibration, and acoustic roughness have become core dimensions for measuring vehicle quality. Engine intake noise, as one of the main noise sources of the vehicle, can easily exceed 100dB in sound pressure level without treatment. This not only poses a potential threat to the health of passengers, but also has a negative impact on the urban ecological environment.

[0003] Intake noise is generated in a complex manner, primarily stemming from the periodic intake fluctuations caused by piston movement within the cylinder. These airflow fluctuations excite acoustic resonance within the intake manifold, generating fundamental frequency noise dominated by low and mid-frequency components. Existing technologies offer relatively good solutions to this problem, such as the automotive engine intake muffler disclosed in CN103452717B. This muffler effectively reduces the number of resonant cavities and adjusts the silencing frequency by changing the volume of the resonant cavities, thus expanding the muffler's silencing range and capability. However, the following drawbacks remain: besides frequency noise, surge noise is also a noise source. When the engine operates near the surge line, airflow separation and recirculation occur within the compressor, generating broadband surge noise, typically concentrated between 1-4kHz. This noise is particularly noticeable during rapid acceleration or deceleration, significantly impacting the driving experience.

[0004] Therefore, in order to solve the above problems, an intake muffler for automobile engines is proposed. Summary of the Invention

[0005] The purpose of this invention is to provide an intake muffler for automobile engines, which solves the problem of wide-band surge noise caused by airflow separation and recirculation inside the compressor, thus affecting the driving experience. Through the design of the inner tube, noise reduction components, and swirling components, it can reduce airflow noise while simultaneously generating heat through friction with PVC oil mist in the airflow, converting some of the airflow's kinetic energy into heat energy, thereby improving the driving experience while reducing surge noise.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] An intake muffler for an automobile engine includes a housing, an inner tube, a noise reduction component, and a swirling adsorption component. The inner tube is coaxially and fixedly sleeved inside the housing. The noise reduction component is coaxially disposed inside the housing and located at both ends of the inner tube. The swirling adsorption component is coaxially disposed inside the inner tube and connected to the housing. When air enters the housing through the intake end, it is first reduced by the noise reduction component, then flows through the swirling adsorption component, and finally exits from the outlet end of the housing. When the air flows inside the housing, it drives the swirling adsorption component to rotate. When the swirling adsorption component rotates, it throws PVC oil mist in the air onto the inner wall of the inner tube.

[0008] Preferably, the noise reduction component includes a tapered tube, and an air inlet and an air outlet are respectively provided on the inner walls of the air inlet and air outlet of the housing. A rotating rod is provided between the air inlet and the air outlet. The tapered tube is coaxially disposed inside the housing and sleeved with the rotating rod. The large opening end of the tapered tube faces the air inlet and is fixedly connected to the inner wall of the housing. A spiral cutting groove is provided on the inner wall of the tapered tube, and the inner wall surface of the spiral cutting groove is frosted.

[0009] Preferably, the cyclone adsorption assembly includes a spiral blade and a sound-absorbing bushing. The spiral blade is coaxially disposed inside the inner tube and fixedly sleeved on the rotating rod, and the spiral direction of the spiral blade is the same as the spiral direction of the spiral cutting groove. The sound-absorbing bushing is fixedly sleeved on the outer wall of the inner tube, and the surface of the inner tube has an array of multiple sound-absorbing holes.

[0010] Preferably, the diameter of the silencing hole decreases from the inside to the outside along the radial direction of the inner tube, and the ratio of the diameters at both ends is 1.5:1 to 3:1.

[0011] Preferably, the spiral blades are configured with a variable pitch, and the pitch of the spiral blades decreases along the air intake direction.

[0012] Preferably, the two ends of the rotating rod are rotatably connected to the corresponding air inlet and air outlet respectively, and an annular gap of 1.5 mm to 2 mm is provided between the spiral blade and the inner wall of the inner tube.

[0013] Preferably, the thickness of the spiral blade is uniformly distributed, and the ratio of the thickness of the spiral blade to the annular gap between the spiral blade and the inner wall of the inner tube is less than 1.5:1.

[0014] Preferably, the sound-absorbing bushing is composed of multiple layers of metal woven mesh, and the porosity of the sound-absorbing bushing decreases from the inside to the outside along the radial direction of the inner tube.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0016] 1. By using noise reduction components and swirling adsorption components, the system utilizes the flow characteristics of air entering the shell, being accelerated through a conical tube, and then driving the high-speed self-rotation of the variable-pitch spiral blades. This creates a powerful centrifugal field without the need for an external power source, throwing the PVC oil mist mixed in the airflow toward the inner tube wall and the sound-absorbing bushing. This not only cleans up the harmful oil mist, effectively preventing the risk of air leakage caused by swelling, aging, and embrittlement of the air intake hose and sealing ring, but also lays the foundation for maintaining the long-term performance of subsequent acoustic components, avoiding the blockage of the sound-absorbing holes or structural failure caused by grease accumulation.

[0017] 2. Through the set swirling adsorption component, during the airflow swirling process, the pressure fluctuation in the airflow generates intense friction with the abrasive spiral cutting groove on the inner wall of the conical tube. Combined with the silencing holes that decrease radially from the inside to the outside and the silencing bushing with a synchronously decreasing porosity gradient, the sound energy is guided, squeezed and converted into a small amount of heat energy dissipation. This breaks the frequency limitation of the single resonant cavity of the traditional muffler, and can accurately lock and filter the wideband surge noise generated during rapid acceleration or deceleration, thereby improving the driving experience. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0019] Figure 2 This is a cross-sectional structural diagram of the present invention;

[0020] Figure 3 This is a schematic diagram of the connection structure between the noise reduction component and the cyclone adsorption component of the present invention;

[0021] Figure 4 For the present invention Figure 3 Enlarged view of the structure of part A in the middle section;

[0022] Figure 5 This is a schematic diagram of the structure of the present invention;

[0023] Figure 6 This is a schematic diagram of the tapered tube structure of the present invention.

[0024] In the diagram: 1. Outer shell; 11. Air inlet duct; 12. Air outlet duct; 13. Rotating rod; 2. Inner tube; 21. Silencing hole; 3. Noise reduction component; 31. Conical tube; 311. Spiral cutting groove; 4. Swirl adsorption component; 41. Spiral blade; 42. Silencing bushing. Detailed Implementation

[0025] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] Please see Figures 1 to 6 This invention provides an intake muffler for automobile engines, the technical solution of which is as follows:

[0027] For details, please refer to Figure 1 , Figure 2 , Figure 3 and Figure 4 An intake muffler for an automobile engine includes a housing 1, an inner tube 2, a noise reduction component 3, and a swirling adsorption component 4. The inner tube 2 is coaxially and fixedly sleeved inside the housing 1. The noise reduction component 3 is coaxially disposed inside the housing 1 and located at both ends of the inner tube 2. The noise reduction component 3 includes a tapered tube 31. An air inlet duct 11 and an air outlet duct 12 are respectively disposed on the inner walls of the air inlet end and the air outlet end of the housing 1. A rotating rod 13 is disposed between the air inlet duct 11 and the air outlet duct 12. The tapered tube 31 is coaxially disposed inside the housing 1 and sleeved with the rotating rod 13. The large opening end of the tapered tube 31 faces the air inlet duct 11 and is fixedly connected to the inner wall of the housing 1. A spiral cutting groove 311 is opened on the inner wall of the tapered tube 31, and the inner wall surface of the spiral cutting groove 311 is frosted.

[0028] It is known that when the engine is running, the car's intake system uses a large number of plastic and rubber parts. PVC materials contain plasticizers. In the high-temperature environment of the engine compartment, these plasticizers may be released from the pipe wall in the form of tiny droplets and form "oil mist" with the high-speed airflow. At the same time, during the production and processing of plastic pipes in the intake manifold, lubricating oil may remain for easy demolding or assembly. Under long-term heat and airflow, it forms a mist. Long-term contact with the rubber seals or plastic connectors in the intake system can cause these parts to swell, age, or become brittle, ultimately leading to air leakage in the intake system. Therefore, under the above-mentioned conditions, on the one hand, after the airflow enters the interior of the outer casing 1 through the air inlet duct 11, it will first gather in the conical tube 31. During the gathering process, the airflow, under its own fluidity, can generate a swirling acceleration effect in conjunction with the spiral cutting groove 311 on the inner wall of the conical tube 31. During the spiral acceleration of the airflow, the mixed PVC oil mist in the airflow is thrown into the interior of the spiral cutting groove 311 by the action of centrifugal force. The PVC oil mist can be cleaned without an external power source, and at the same time, the air intake system can be effectively prevented from leaking. On the other hand, the frosted surface of the spiral cutting groove 311 can greatly increase the friction coefficient of the air boundary layer. When the PVC oil mist enters the spiral cutting groove 311 and comes into contact with the frosted surface, due to the roughness of the frosted surface, the particles and the wall will generate intense shear friction, thereby efficiently converting the pressure fluctuation in the airflow into a small amount of heat energy. Furthermore, the geometry of the spiral cutting groove 311 and the microstructure of the frosted surface work together to change the sound path and reduce the sound impedance, creating a composite noise reduction environment and effectively reducing surge noise.

[0029] As one embodiment of the present invention, refer to Figure 2 , Figure 3 , Figure 4 , Figure 5 and Figure 6 The cyclone adsorption component 4 is coaxially arranged inside the inner tube 2 and connected to the outer shell 1. When air enters the inner shell 1 through the air inlet end of the outer shell 1, it is first reduced by the noise reduction component 3 and then flows through the cyclone adsorption component 4 before being discharged from the air outlet end of the outer shell 1. When the air flows inside the outer shell 1, it drives the cyclone adsorption component 4 to rotate. When the cyclone adsorption component 4 rotates, it throws the PVC oil mist in the air onto the inner wall of the inner tube 2. The cyclone adsorption component 4 includes a spiral blade 41 and a sound-absorbing bushing 42. The spiral blade 41 is coaxially arranged inside the inner tube 2 and fixedly sleeved on the rotating rod 13. The spiral direction of the spiral blade 41 is the same as the spiral direction of the spiral cutting groove 311. The sound-absorbing bushing 42 is fixedly sleeved on the outer wall of the inner tube 2. The surface of the inner tube 2 has multiple sound-absorbing holes 21 arrayed.

[0030] Under the above conditions, on the one hand, when the airflow flows out through the small opening end of the conical tube 31, it enters the inner tube 2 through the spiral cutting groove 311 and is blocked by the spiral blade 41 and continues to rotate. During the rotation, the centrifugal force is used to throw the PVC oil mist particles, which are much denser than air, toward the inner wall of the inner tube 2. Then, they pass through the silencing hole 21 and come into contact with the sound-absorbing bushing 42 sleeved on the outside of the inner tube 2. On the other hand, when the airflow carrying noise passes through the inner tube 2, the sound waves will pass through the silencing hole 21 and enter the sound-absorbing bushing 42. The sound waves generate viscous friction in the tiny holes and the gaps in the metal woven mesh, which efficiently converts the sound energy into heat energy for dissipation, thereby achieving a further noise reduction effect.

[0031] As one embodiment of the present invention, refer to Figure 3 , Figure 4 and Figure 5 The diameter of the silencing hole 21 decreases from the inside to the outside along the radial direction of the inner tube 2, and the ratio of the diameters at both ends is 1.5:1 to 3:1.

[0032] It is known that the traditional constant-diameter silencing hole 21 will produce a large change in acoustic impedance when sound waves enter, resulting in a large amount of sound energy being directly reflected back to the air intake. Therefore, this solution is adopted. By utilizing the change in the diameter at both ends of the silencing hole 21, sound waves can be guided into the interior of the hole more efficiently, significantly reducing the acoustic reflectivity of the orifice, allowing more noise energy to smoothly enter the silencing bushing 42 for attenuation. At the same time, as the diameter of the silencing hole 21 decreases, the viscous damping effect of the sound waves in the pore is enhanced, effectively increasing the friction area and friction intensity between the sound waves and the hole wall, thereby more efficiently converting sound energy into heat energy for consumption and improving the silencing efficiency per unit area. Furthermore, limiting the diameter at both ends of the silencing hole 21 to between 1.5:1 and 3:1 can ensure both the acoustic gradient silencing performance and maintain the structural strength of the inner tube 2, while ensuring that the dynamic response of the air intake system is not affected.

[0033] As one embodiment of the present invention, refer to Figure 2 and Figure 3 The spiral blade 41 is configured with a variable pitch, and the pitch of the spiral blade 41 decreases along the air intake direction.

[0034] Under the aforementioned conditions, the variable pitch structure of the helical blade 41 breaks the periodicity of the physical structure. The changing spacing of the helical blades 41 means that the acoustic impedance of the sound wave propagation path is continuously changing. This non-periodic structure can scatter the sound energy of a single frequency into a wider spectrum, thereby suppressing the formation of standing waves at specific frequencies. At the same time, at the rear end of the airflow path, as the pitch decreases, the contact frequency between the airflow and the helical blade 41 and the inner tube 2 wall increases significantly, intensifying shear friction. This allows the pressure pulsations in the airflow to be converted into trace amounts of heat energy more efficiently through intense friction with the wall surface, abrasive surface, and oil mist particles, enhancing the effect of energy dissipation-based noise reduction.

[0035] As one embodiment of the present invention, refer to Figure 2 and Figure 3 The two ends of the rotating rod 13 are rotatably connected to the corresponding air inlet duct 11 and air outlet duct 12 respectively. A 1.5 mm to 2 mm annular gap is provided between the spiral blade 41 and the inner wall of the inner tube 2. The thickness of the spiral blade 41 is uniformly set, and the ratio of the thickness of the spiral blade 41 to the annular gap between the spiral blade 41 and the inner wall of the inner tube 2 is less than 1.5:1.

[0036] Under the aforementioned conditions, on the one hand, the precisely set 1.5 mm to 2 mm annular gap between the spiral blade 41 and the inner wall of the inner tube 2 completely avoids friction and collision between the spiral blade 41 and the inner tube 2 during rotation, effectively eliminating secondary noise generated by mechanical wear and significantly improving the operational stability and service life of the device. At the same time, this annular gap forms a natural "air damping layer." When sound waves pass through this annular gap, they generate severe viscous dissipation and pressure drop. This acoustic effect, similar to a "squeezed membrane," can specifically absorb high-frequency micro-vibrations in the airflow, further enhancing the noise reduction effect. On the other hand, the 1.5 mm to 2 mm gap setting can prevent tip vortex noise caused by an excessively small annular gap, and ensure that most of the airflow is effectively guided by the spiral blade 41 to form a strong vortex. The centrifugal force generated is sufficient to accurately throw PVC oil mist into the gap, thereby achieving long-term and stable noise reduction while ensuring efficient and smooth air intake.

[0037] As one embodiment of the present invention, refer to Figure 3 and Figure 4 The sound-absorbing bushing 42 is composed of multiple layers of metal woven mesh, and the porosity of the sound-absorbing bushing 42 decreases from the inside to the outside along the radial direction of the inner tube 2.

[0038] Under the aforementioned conditions, the tiny PVC oil mist particles ejected by the spiral blade 41 pass through the silencing holes 21 and first enter the inner layer of the relatively sparse silencing bushing 42. As the porosity decreases, the outer silencing bushing 42 intercepts and locks the PVC oil mist between the bushing layers. This gradient interception effect prevents the oil mist from rapidly forming a film and clogging the surface, ensuring that the silencing bushing 42 maintains good sound wave penetration during long-term use. It also completely solves the problem of aging in the air intake system caused by oil mist leakage.

[0039] Working principle:

[0040] External air first enters the interior of the outer casing 1 through the air inlet duct 11 at the air inlet end of the outer casing 1. The airflow first passes through the conical tube 31 of the noise reduction component 3. The spiral cutting groove 311 with a frosted surface on the inner wall of the conical tube 31, combined with the airflow's own fluidity, generates an initial swirling acceleration. During this process, the frosted surface increases the friction coefficient of the air boundary layer, converting some pressure fluctuations into a small amount of heat energy dissipation. Subsequently, the airflow enters the inner tube 2. Since the two ends of the rotating rod 13 are rotatably connected to the air inlet duct 11 and the air outlet duct 12 respectively, the airflow power drives the spiral blade 41 fixed on the rotating rod 13 to rotate at high speed. The centrifugal force generated throws the PVC oil mist that has been released from the air due to high temperature onto the inner wall of the inner tube 2 and into the spiral cutting groove 311 for interception and cleaning, thus removing the PVC oil mist from the source. The design avoids air leakage caused by the swelling and aging of the intake system seals due to oil mist. At the same time, the sound waves carrying noise permeate outward through the array of silencing holes 21 distributed on the surface of the inner tube 2. By utilizing the changes in the diameter of the silencing holes 21 and the changes in the porosity of the silencing bushing 42, the sound waves generate intense viscous friction and multiple interference reflections when passing through the multi-layer composite medium. Combined with the variable pitch design of the spiral blade 41 with the pitch decreasing along the intake direction, the propagation path of the 1-4kHz broadband surge noise is effectively broken and the acoustic impedance is reduced. Finally, the airflow is damped and regulated when passing through the annular gap between the spiral blade 41 and the inner wall of the inner tube 2. Under the premise of ensuring a stable flow field and no mechanical wear, the clean and noise-reduced airflow is finally smoothly discharged from the exhaust duct 12.

[0041] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An intake muffler for an automobile engine, characterized in that: The device includes an outer shell (1), an inner tube (2), a noise reduction component (3), and a swirling adsorption component (4). The inner tube (2) is coaxial and fixedly fitted inside the outer shell (1). The noise reduction component (3) is coaxially disposed inside the outer shell (1) and located at both ends of the inner tube (2). The swirling adsorption component (4) is coaxially disposed inside the inner tube (2) and connected to the outer shell (1). When air enters the inner shell (1) through the air inlet end of the outer shell (1), it is first reduced by the noise reduction component (3) and then flows through the swirling adsorption component (4) before being discharged from the air outlet end of the outer shell (1). When the air flows inside the outer shell (1), it drives the swirling adsorption component (4) to rotate. When the swirling adsorption component (4) rotates, it throws the PVC oil mist in the air onto the inner wall of the inner tube (2).

2. The intake muffler for an automobile engine according to claim 1, characterized in that: The noise reduction component (3) includes a tapered tube (31). The inner walls of the air inlet and air outlet of the outer shell (1) are respectively provided with an air inlet tube (11) and an air outlet tube (12). A rotating rod (13) is provided between the air inlet tube (11) and the air outlet tube (12). The tapered tube (31) is coaxially arranged inside the outer shell (1) and sleeved with the rotating rod (13). The large opening end of the tapered tube (31) faces the air inlet tube (11) and is fixedly connected to the inner wall of the outer shell (1). The inner wall of the tapered tube (31) is provided with a spiral cutting groove (311). The inner wall surface of the spiral cutting groove (311) is frosted.

3. The intake muffler for an automobile engine according to claim 2, characterized in that: The swirling adsorption assembly (4) includes a spiral blade (41) and a sound-absorbing bushing (42). The spiral blade (41) is coaxially disposed inside the inner tube (2) and fixedly sleeved on the rotating rod (13). The spiral direction of the spiral blade (41) is the same as the spiral direction of the spiral cutting groove (311). The sound-absorbing bushing (42) is fixedly sleeved on the outer wall of the inner tube (2). The surface of the inner tube (2) has a plurality of sound-absorbing holes (21).

4. The intake muffler for an automobile engine according to claim 3, characterized in that: The diameter of the silencing hole (21) decreases from the inside to the outside along the radial direction of the inner tube (2), and the ratio of the diameters at both ends is 1.5:1 to 3:

1.

5. An intake muffler for an automobile engine according to claim 3, characterized in that: The spiral blade (41) is configured with a variable pitch, and the pitch of the spiral blade (41) decreases along the air intake direction.

6. The intake muffler for an automobile engine according to claim 3, characterized in that: The two ends of the rotating rod (13) are rotatably connected to the corresponding air inlet (11) and air outlet (12) respectively, and an annular gap of 1.5 mm to 2 mm is provided between the spiral blade (41) and the inner wall of the inner tube (2).

7. An intake muffler for an automobile engine according to claim 3, characterized in that: The thickness of the spiral blade (41) is uniformly set, and the ratio of the thickness of the spiral blade (41) to the annular gap between the spiral blade (41) and the inner wall of the inner tube (2) is less than 1.5:

1.

8. An intake muffler for an automobile engine according to claim 3, characterized in that: The sound-absorbing bushing (42) is composed of multiple layers of metal woven mesh, and the porosity of the sound-absorbing bushing (42) decreases from the inside to the outside along the radial direction of the inner tube (2).

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