A system, method, and apparatus for active exhaust noise control

Abstract

The application discloses a system, method and device for active noise control of exhaust. The system comprises an exhaust pipe and a muffler for purifying exhaust gas, which transmits a primary noise transmission system generated by a power system; a microphone assembly system collects the primary noise signal in the pipe, and generates an error signal matrix through filtering processing; a narrow-band reference signal matrix is obtained through filtering processing according to a crankshaft speed signal collected by a rotating speed processing system; meanwhile, a CAN analysis system analyzes a CAN message signal transmitted, and obtains a CAN state signal matrix through analysis processing; a controller system obtains a secondary sound source signal for driving a loudspeaker assembly system through built-in adaptive algorithm operation according to the received error signal matrix, the reference signal matrix and the CAN state signal matrix. Compared with a traditional exhaust passive noise reduction, the application can better inhibit low-frequency noise, greatly reduce the volume of the muffler, optimize the total layout space of the exhaust pipe, and optimize back pressure, thereby improving the thermal efficiency of the engine.

Description

Technical Field

[0001] This invention relates to the field of active noise control technology for pipelines, specifically designing a system, method, and device for active noise control of exhaust gas. Background Technology

[0002] Current active noise control is mainly used in vehicles, aircraft, high-speed trains, and submarines for cabin noise reduction to improve driving and passenger comfort. For traditional internal combustion engines, the main noise generated during power generation is order noise. Traditional noise reduction methods can significantly reduce mid-to-high frequency noise through materials, structures, and tuning. However, passive noise control for low-to-mid frequency noise is difficult. Active noise control technology is mature in terms of performance and stability for low-frequency noise control, and its current application is mainly in multi-channel cabin noise reduction, with limited use for external noise control.

[0003] Traditional gasoline vehicles, range-extended vehicles, and hybrid vehicles have a large proportion of intake and exhaust noise. Traditional methods reduce exhaust noise through muffler design, but these mufflers occupy a large volume and increase weight, limiting vehicle lightweight development and cost optimization. With the emergence of range-extended hybrid vehicles, the vehicle has both an exhaust system and a battery pack, which conflict in the use of chassis space. If the exhaust muffler is eliminated or the exhaust pipeline is optimized, the battery pack can be further improved, thereby increasing the driving range. At the same time, due to the back pressure of the exhaust system, the engine thermal efficiency is not optimal.

[0004] Exhaust system noise is particularly prominent in traditional internal combustion engines, hybrid vehicles, and range-extended electric vehicles, directly impacting external environmental noise levels and in-vehicle acoustic quality. Currently, mainstream exhaust noise reduction technology relies on passive mufflers. These mufflers utilize internal porous tubes, baffles, expansion chambers, resonant chambers, and sound-absorbing materials to attenuate noise through the principles of sound wave reflection, interference, and absorption. Passive mufflers offer good control over mid-to-high frequency noise, but their noise reduction performance is highly dependent on size and length, and their ability to handle longer-wavelength low-frequency noise is limited. To meet increasingly stringent noise regulations, manufacturers often have to increase the volume and complexity of mufflers, directly leading to increased exhaust system weight, limited space, and increased exhaust back pressure. Increased exhaust back pressure hinders exhaust gas discharge, reducing engine fuel economy and thermal efficiency, contradicting the development goals of lightweight vehicles and increased driving range (especially important for hybrid / range-extended models).

[0005] To address this, Chinese invention patent CN103982281A discloses an active noise control system and its control method for automotive exhaust systems. This method mainly controls the low-frequency noise of exhaust based on engine operating parameters (such as engine speed). However, it relies on engine speed to generate a reference signal, and its control strategy is relatively fixed, making it unable to dynamically adapt to complex operating conditions.

[0006] Therefore, it is urgent to develop and design a control method that can accurately identify multiple operating conditions and simultaneously switch between multiple strategies. Summary of the Invention

[0007] The present invention aims to provide a system, method and apparatus for active exhaust noise control, which is suitable for improving the sound quality inside and outside of vehicles with traditional internal combustion engines. It is of great significance for vehicle lightweighting, and at the same time, it can further improve the driving range in the battery pack layout of hybrid range-extended vehicles.

[0008] The objective of this invention is achieved through the following technical solution:

[0009] For an active exhaust noise control system, the system includes:

[0010] Primary noise transmission system 200, configured to provide the environment required for noise reduction transmission;

[0011] The microphone assembly system 300 is configured to pick up the noise signal inside the tube in real time and send it to the controller system 600;

[0012] The CAN parsing system 500 is configured to receive physical signals collected and processed by the vehicle 100, and parse the signals into usable signals to send to the controller system 600.

[0013] The speed processing system 400 is configured to receive the PWM signal from the engine crankshaft sensor, and obtain a narrowband reference signal and a wideband reference signal usable by the algorithm through filtering and smoothing, and send them to the controller system 600.

[0014] The controller system 600 is configured to receive error signals, CAN gateway signals, crankshaft speed narrowband signals and broadband vibration signals, and output secondary sound source control signals through adaptive algorithm calculations.

[0015] The loudspeaker assembly system 700 is configured to output a sound source that cancels out primary noise.

[0016] Preferably, the primary noise transmission system 200 includes an exhaust pipe 201 for discharging exhaust gas and transmitting noise, and a muffler 202 for passively attenuating mid-to-high frequency noise within the pipe, wherein the muffler 202 is installed in the middle and rear part of the exhaust pipe 201.

[0017] Preferably, the microphone assembly system 300 includes:

[0018] Microphone sensor 303 is used to pick up the attenuated noise signal within the exhaust pipe 201;

[0019] Microphone branch tube 301 is used to reduce tube temperature and attenuate noise inside the tube;

[0020] The microphone sensor 303 is installed at the end of the microphone branch pipe 301, which is installed 200-400mm inside the end of the exhaust tailpipe 203. The microphone branch pipe 301 forms an angle of 45-85° with the exhaust airflow direction.

[0021] Preferably, in the CAN parsing system, the physical signals collected and processed by the vehicle include vehicle speed, accelerator pedal opening, brake pedal opening, gear position, SOC battery level, and exhaust system temperature.

[0022] Preferably, the loudspeaker assembly system 700 includes a loudspeaker 701 for receiving noise cancellation sound source signals, a housing 702, and a housing branch pipe 703. The loudspeaker 701 is detachably mounted on the housing 702. A sealed space for increasing low-frequency response is formed between the housing 702 and the inner surface of the loudspeaker 701. A space for canceling noise transmission is formed between the outer surface of the housing 702 and the outer surface of the loudspeaker 701. The edge of the space is welded to the housing branch pipe 703, and the housing branch pipe 703 is screwed to the exhaust tailpipe 203.

[0023] The present invention also provides a method for active exhaust noise control, the method comprising the following steps:

[0024] S1. Collect and analyze vehicle CAN signals for vehicle speed, accelerator pedal opening, brake pedal opening, gear position, SOC battery level, and exhaust system temperature to form a vehicle state vector. ;

[0025] Among them, the vehicle state vector , representing idle speed, creep, constant speed, and full throttle acceleration conditions respectively. This vector is a one-hot vector, with one and only one value of 1 and the rest of them being 0;

[0026] S2. Collect noise signals from the location of the error microphone inside the exhaust pipe and generate an error signal matrix. ;

[0027] Among them, the error signal matrix L represents the number of residual noise signals collected from the pipeline;

[0028] S3. Acquire engine crankshaft speed signal, process and generate narrowband reference signal matrix. Broadband reference signal ;

[0029] S4, Narrowband Filter Coefficient Matrix Received via transfer function matrix Narrowband reference signal matrix for filtering and the aforementioned error noise matrix Adaptive coefficient update to generate the narrowband control signal matrix for the loudspeaker. ;

[0030] Broadband filter coefficient matrix Received via transfer function matrix Filtered wideband reference signal matrix and the aforementioned error noise matrix Adaptive coefficient update to generate loudspeaker broadband control signal matrix ;

[0031] S5, via vehicle state vector Determine the narrowband control signal matrix of the loudspeaker and broadband control signal matrix The operating state generates the final speaker control signal matrix. ;

[0032] S6, Speaker Control Signal Matrix Through the transfer function matrix Secondary signal matrix generated at the location of the error microphone inside the exhaust pipe , and the primary noise matrix The noise is superimposed and canceled out, thereby achieving active noise control of the exhaust.

[0033] Preferably, in step S3, the narrowband reference signal matrix is ​​represented as follows:

[0034] ;

[0035] The broadband reference signal is represented as:

[0036] ;

[0037] in Z represents the frequency corresponding to the exhaust order noise to be controlled, and Z represents the number of exhaust order noise frequencies to be controlled.

[0038] Preferably, in step S4, the narrowband reference signal matrix It can be represented as:

[0039] , ,in I is the length of the time-domain transfer function;

[0040] Meanwhile, the narrowband filter coefficient matrix The update of the coefficients can be expressed as: , ,in This is the step size factor for the narrowband filter. This is the convergence factor of the narrowband filter;

[0041] and the secondary speaker narrowband control signal matrix It can be represented as: ,in To correspond to the accumulation of reference signals at the current time and before I-1 time when the narrowband filter is operating, the symbol... This represents signal convolution.

[0042] Preferably, in step S4, the broadband reference signal matrix It can be represented as:

[0043] , ,in , It is obtained by filtering the estimated value of the transfer function from the k-th vibration signal through the loudspeaker to the l-th error microphone;

[0044] Broadband filter coefficient matrix The coefficients are updated, represented as follows: ,in This is the step size factor for the broadband filter. This is the step size factor for the broadband filter;

[0045] Secondary speaker broadband control signal matrix It can be represented as: ,in This is to account for the accumulation of reference signals at the current time and before I-1 when the narrowband filter is in operation.

[0046] Preferably, in steps S5-S6: when the vehicle state is determined to be constant speed and full throttle, then the speaker control signal matrix... When the vehicle status is determined to be idling or creeping, the speaker control signal matrix... Ultimately, , .

[0047] Compared with the prior art, the advantages or beneficial effects of the technical solution of this application include:

[0048] 1. ANC technology is extremely efficient at reducing low-frequency noise, especially internal combustion engine noise. This method, through precise algorithm control, can generate anti-phase sound waves that are out of phase with the original noise, thus achieving effective cancellation.

[0049] 2. This method integrates multi-dimensional vehicle signals, enabling intelligent identification of different operating conditions such as idling, creeping, and acceleration, and dynamically switching control strategies. This not only improves noise reduction performance and system robustness under all operating conditions but also makes software control of engine noise levels possible, allowing for adaptive sound design to meet the acoustic design requirements of different brands or vehicle models. For example, the system can retain or enhance certain pleasant sound levels while ensuring noise reduction, thus enhancing the driving experience.

[0050] 3. Traditionally, mufflers enlarged to reduce noise can increase exhaust back pressure, hindering exhaust gas discharge and impairing engine performance. The introduction of ANC technology makes it possible to design an active free-flow exhaust system while ensuring noise reduction, thereby minimizing airflow restriction and reducing exhaust back pressure.

[0051] 4. The modified exhaust pipe structure optimizes chassis layout space, allowing for increased battery pack volume in hybrid and range-extended vehicles, thus improving pure electric range. Simultaneously, reducing the number of mufflers in the exhaust system enhances vehicle lightweighting. Attached Figure Description

[0052] Figure 1 This is a schematic diagram of the active exhaust noise control system of the present invention;

[0053] Figure 2 This is a schematic diagram of the active exhaust noise control method of the present invention;

[0054] Figure 3 This is a schematic diagram of the active exhaust noise control device of the present invention;

[0055] Figure 4 The results of the active exhaust noise control of this invention at idle speed on a real vehicle;

[0056] Figure 5 The results show the acceleration of a real vehicle for the active exhaust noise control method of this invention.

[0057] In the diagram: 100 - Vehicle; 200 - Primary noise transmission system; 201 - Exhaust pipe; 202 - Muffler; 203 - Exhaust tailpipe; 300 - Microphone assembly system; 301 - Microphone branch pipe; 302 - Waterproof, dustproof, and heat-insulating material; 303 - Microphone sensor; 400 - Speed ​​processing system; 500 - CAN parsing system; 600 - Controller system; 700 - Speaker assembly system; 701 - Speaker; 702 - Housing; 703 - Housing branch pipe. Detailed Implementation

[0058] The following detailed description of the embodiments of this application, in conjunction with the accompanying drawings, will provide a thorough understanding of how this application uses technical means to solve technical problems and achieve corresponding technical effects, enabling its implementation. The embodiments of this application and the various features within them can be combined with each other without conflict, and all resulting technical solutions are within the protection scope of this application.

[0059] It should be clearly stated that the embodiments described below are merely some embodiments of this application, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0060] Example 1:

[0061] Figure 1 This is a schematic diagram of an exemplary implementation of active exhaust noise control system. It should be noted that the active exhaust noise control method of this disclosure can be applied to the active exhaust noise control apparatus of this disclosure, which can be equipped on a vehicle.

[0062] like Figure 1 As shown, the system includes a vehicle 100, a primary noise transmission system 200 installed in the vehicle's engine compartment chassis for transmitting primary noise, a microphone assembly system 300 for acquiring the noise characteristics of the exhaust system, a speed processing system 400 for acquiring reference signals, a CAN parsing system 500 for receiving CAN message signals required by the vehicle's active exhaust noise control system, a controller system 600 for determining the vehicle's operating status in real time and calculating and generating noise reduction signals by receiving microphone error signals, speed reference signals, and CAN message signals, and a speaker output system 700 for converting electrical signals into acoustic signals for noise cancellation.

[0063] The microphone acquisition system 300 and the speaker output system 700 are installed on the primary noise transmission system 200, and together they form an active and passive exhaust noise reduction system.

[0064] The speed processing system 400 acquires signals through hard-wired speed data and mainly consists of an engine crankshaft sensor and a signal conversion module to improve the accuracy of speed changes and reduce the system delay introduced by the reference signal.

[0065] The CAN parsing system 500 includes signals from the vehicle gateway, such as vehicle speed, accelerator pedal opening, brake pedal opening, SOC (State of Charge), gear position, exhaust system temperature, and microphone / speaker diagnostic signals. It determines vehicle operating conditions (idle, creep, constant speed, coasting, gentle acceleration, and rapid acceleration) based on gear position, vehicle speed, and accelerator pedal opening signals, and further determines deceleration and emergency braking conditions based on brake pedal opening. It also assesses engine noise characteristics based on SOC levels. These signals control noise reduction performance under various operating conditions. The exhaust system temperature function determines whether to temporarily shut down the speakers to prevent environmental factors from causing abnormalities. Diagnostic signals are used to identify the real-time condition of the speakers and microphones, preventing abnormal noises caused by external environmental changes or hardware damage.

[0066] The controller system 600 collects microphone signals from the acquisition tube, receives and processes the speed reference signal, and generates output signals by combining the internal logic strategy of the algorithm, the system transmission path, and calibration parameters.

[0067] The speaker output system 700 converts the electrical signal output by the algorithm into an analog signal for playback. This sound is transmitted through a pipe to the exhaust tailpipe to cancel out the low-frequency noise generated by the engine, thereby drastically reducing the sound emitted from the exhaust tailpipe and reducing the noise pollution of the car to the environment.

[0068] Example 2:

[0069] Figure 2 This is a schematic diagram of an exemplary implementation of an active exhaust noise control method, including the following steps:

[0070] S1. Collect and analyze vehicle CAN signals for vehicle speed, accelerator pedal opening, brake pedal opening, gear position, SOC battery level, and exhaust system temperature to form a vehicle state vector. Vehicle state vector , representing idle speed, creep, constant speed, and full throttle acceleration conditions respectively. This vector is a one-hot vector, with exactly one value of 1 and the rest of the values ​​being 0.

[0071] S2. Collect noise signals from the location of the error microphone inside the exhaust pipe and generate an error signal matrix. The error signal matrix , where L is the number of residual noise signals collected from the pipeline.

[0072] S3. Acquire engine crankshaft speed signal, process and generate narrowband reference signal matrix. Broadband reference signal ;

[0073] The narrowband reference signal matrix is ​​represented as follows:

[0074]

[0075] The broadband reference signal is represented as:

[0076]

[0077] in, Z represents the frequency corresponding to the exhaust order noise to be controlled, and Z represents the number of exhaust order noise frequencies to be controlled.

[0078] S4, Narrowband Filter Coefficient Matrix Received via transfer function matrix Narrowband reference signal matrix for filtering and the aforementioned error noise matrix Adaptive coefficient update to generate the narrowband control signal matrix for the loudspeaker. Broadband filter coefficient matrix Received via transfer function matrix Filtered wideband reference signal matrix and the aforementioned error noise matrix Adaptive coefficient update to generate loudspeaker broadband control signal matrix ;

[0079] Among them, through the transfer function matrix Narrowband reference signal matrix for filtering , can be represented as:

[0080] , ;in I is the length of the time-domain transfer function.

[0081] Narrowband filter coefficient matrix The update of the coefficients can be expressed as:

[0082] , ,in This is the step size factor for the narrowband filter. This is the convergence factor for the narrowband filter.

[0083] The aforementioned transfer function matrix Filtered wideband reference signal matrix It can be represented as:

[0084] , ,in , It is obtained by filtering the estimated value of the transfer function from the k-th vibration signal through the loudspeaker to the l-th error microphone.

[0085] Broadband filter coefficient matrix The coefficients are updated, represented as follows: ,in This is the step size factor for the broadband filter. This is the step size factor for the broadband filter.

[0086] S5, via vehicle state vector Determine the narrowband control signal matrix of the loudspeaker and broadband control signal matrix The operating state generates the final speaker control signal matrix. ;

[0087] Secondary speaker narrowband control signal matrix It can be represented as: ,in To correspond to the accumulation of reference signals at the current time and before I-1 time when the narrowband filter is operating, the symbol... This represents signal convolution.

[0088] Secondary speaker broadband control signal matrix It can be represented as: ,in This is to account for the accumulation of reference signals at the current time and before I-1 when the narrowband filter is in operation.

[0089] S6, Speaker Control Signal Matrix Through the transfer function matrix Secondary signal matrix generated at the location of the error microphone inside the exhaust pipe , and the primary noise matrix To perform superposition and offsetting;

[0090] Speaker Narrowband Control Signal Matrix and broadband control signal matrix The working state is determined by the vehicle state vector. The narrowband control signal matrix is ​​determined when the vehicle state is judged to be constant speed and full throttle. The final speaker control signal matrix takes effect. When the vehicle status is determined to be idling or creeping, the broadband control signal matrix... , Secondary signal matrix It can be represented as: , .

[0091] Example 3:

[0092] Figure 3 This is a schematic diagram of an exhaust active noise control device according to an exemplary implementation, including the following main components:

[0093] During the process of converting physical heat energy into mechanical energy, the main noise sources are the air combustion noise generated by the compression and explosion of fuel and gas, the mechanical noise generated by the reciprocating motion of the piston, and the airflow noise generated by intake and exhaust. The exhaust gas and airflow noise flow into the exhaust pipe 201 through the exhaust manifold. A muffler 202 is installed in the middle and rear of the exhaust pipe to purify the exhaust gas and reduce high-frequency noise. Finally, the exhaust gas and airflow noise are discharged outside the vehicle through the exhaust tailpipe 203. A single small-volume muffler 202 cannot completely reduce the noise until the target requirements are met. Now, the low-frequency noise in the exhaust tailpipe is reduced by active noise reduction methods and devices.

[0094] The microphone assembly 300 is installed 200-400mm inward from the end of the exhaust tailpipe 203, at an angle of 45-85° to the direction of the exhaust airflow. To prevent the airflow from directly entering the interior of the branch pipe 301 of the microphone assembly 300, the branch pipe 301 is inserted into the exhaust tailpipe 203 by 3-5mm. The exterior is welded by laser. The interior of the branch pipe 301 is made of waterproof, dustproof and heat-insulating material 302, which can effectively protect the performance and service life of the end A2B microphone 303. This device can effectively pick up low-frequency noise from the exhaust tailpipe 203. It is used for error signal pickup and actual control point of noise reduction in the exhaust active noise control system.

[0095] The CAN gateway 401 sends vehicle speed, accelerator pedal opening, brake pedal opening, gear position, SOC (State of Charge), exhaust system temperature signal, and microphone / speaker diagnostic signal to the controller 601 for message parsing and algorithmic logic control. For example, in constant speed operation, the gear position signal indicates a forward gear, the vehicle speed fluctuates within 2 km / h, and the engine speed signal is present while the accelerator pedal opening remains within a certain percentage fluctuation of 2%. This indicates a constant speed operation. Because the engine's power generation efficiency requirements vary under different SOC states, resulting in differences in noise characteristics, parameters for different SOC ranges are calibrated. To ensure stable system operation in various environments, exhaust system temperature signal and microphone / speaker diagnostic signal are added. In extremely cold environments, to prevent speaker freezing and performance changes due to low temperatures, and to prevent abnormal noises during initial operation after a period of inactivity, the exhaust system temperature signal algorithm delays the activation of the exhaust noise control system. Since the microphone and speaker components operate in harsh environments and are used continuously for extended periods, damage may occur. The microphone / speaker diagnostic signal algorithm determines if the system can disable this function; after the hardware recovers, the system can be restarted normally.

[0096] The crankshaft sensor signal 501 is processed by the conversion module and sent to the controller 601. The main functions of the controller 601 are to generate a wide and narrow band reference signal matrix from the speed signal, to generate an error signal matrix by low-pass filtering of the error signal, to control the operating condition and robustness logic strategy, and to output a noise reduction signal matrix from the algorithm. The controller 601 is installed in the vehicle.

[0097] The speaker assembly 700 consists of a mid-low frequency speaker 701, a custom speaker housing 702, and a housing support tube 703. The mid-low frequency speaker 701 is a 6.5-inch high-sensitivity speaker with a high-temperature resistant paper cone, bolted to the custom housing 702, with the edges sealed with heat-insulating sealant. The custom housing 702 and the back of the mid-low frequency speaker 701 form a sealed space to increase the speaker's low-frequency response. Because the device is installed in a sealed pipe, a single-sided pressure relief valve needs to be designed on the back of the housing. Considering the weight and volume of the custom housing, a hook is designed on the edge of the housing and connected to the vehicle body via a rubber lug. The custom housing 702 and the front of the mid-low frequency speaker 701 form a separate space for the speaker to generate noise cancellation. The edge of this space is welded to the housing support tube 703, which is bolted to the exhaust tailpipe 203.

[0098] In this embodiment, a customized modification was performed on the exhaust system of a vehicle, and active exhaust noise control was implemented at the exhaust tailpipe. The test results are as follows: Figure 4 and Figure 5 As shown. Figure 4 The horizontal axis represents the noise reduction frequency, and the vertical axis represents the sound pressure level. When tested at 15cm from the tailpipe opening under idling conditions, the noise within 300Hz can be reduced by more than 10dBA, which is better than the low-frequency noise reduction performance of traditional exhaust systems. Figure 5 To accelerate noise control under operating conditions, the horizontal axis represents the engine speed range, and the vertical axis represents the sound pressure level. The active exhaust noise control system exhibits superior noise characteristics compared to the original vehicle exhaust system. This system significantly suppresses second-order noise, contributing 5-8 dBA in noise reduction within the 1500-5000 rpm range. The active exhaust noise control system, method, and device proposed in this invention achieve better control of low- and mid-frequency noise within the exhaust pipe.

[0099] In summary, those skilled in the art can make various modifications and improvements without departing from the technical solution of this invention. These modifications and improvements should also be considered within the scope of protection of this invention, and will not affect the effectiveness of the invention or the practicality of the patent. The scope of protection claimed in this application shall be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A system for active exhaust noise control, characterized in that, include: A primary noise transmission system (200) configured to provide the environment required for noise reduction transmission; A microphone assembly system (300) is configured to pick up the noise signal inside the tube in real time and send it to the controller system (600). A CAN parsing system (500) is configured to receive physical signals collected and processed by the vehicle (100) and parse the signals into usable signals to send to the controller system (600). The speed processing system (400) is configured to receive the PWM signal from the engine crankshaft sensor, and obtain a narrowband reference signal and a wideband reference signal usable by the algorithm through filtering and smoothing, and send them to the controller system (600); The controller system (600) is configured to receive error signals, CAN gateway signals, crankshaft speed narrowband signals and broadband vibration signals, and output secondary sound source control signals through adaptive algorithm calculations. The loudspeaker assembly system (700) is configured to output a sound source that cancels out primary noise.

2. The system according to claim 1, characterized in that, The primary noise transmission system (200) includes an exhaust pipe (201) for discharging exhaust gas and transmitting noise, and a muffler (202) for passive attenuation of mid-to-high frequency noise within the pipe, the muffler (202) being installed in the middle and rear part of the exhaust pipe (201).

3. The system according to claim 2, characterized in that, The microphone assembly system (300) includes: A microphone sensor (303) is used to pick up the attenuated noise signal inside the exhaust pipe (201); Microphone branch tube (301) is used to reduce tube temperature and attenuate noise inside the tube; The microphone sensor (303) is installed at the end of the microphone branch pipe (301), which is installed 200-400mm inside the end of the exhaust tailpipe (203). The microphone branch pipe (301) forms an angle of 45-85° with the exhaust airflow direction.

4. The system according to claim 1, characterized in that, The physical signals collected and processed by the vehicle in the CAN parsing system include vehicle speed, accelerator pedal opening, brake pedal opening, gear position, SOC (State of Charge) battery level, and exhaust system temperature.

5. The system according to claim 3, characterized in that, The loudspeaker assembly system (700) includes a loudspeaker (701) for receiving noise cancellation source signals, a housing (702) and a housing branch pipe (703). The loudspeaker (701) is detachably mounted on the housing (702). A sealed space for increasing low-frequency response is formed between the housing (702) and the inside of the loudspeaker (701). A space for canceling noise transmission is formed between the outer side of the housing (702) and the outer side of the loudspeaker (701). The edge of the space is welded to the housing branch pipe (703). The housing branch pipe (703) is screwed to the exhaust tailpipe (203).

6. A method for active exhaust noise control, characterized in that, Includes the following steps: S1. Collect and analyze vehicle CAN signals for vehicle speed, accelerator pedal opening, brake pedal opening, gear position, SOC battery level, and exhaust system temperature to form a vehicle state vector. ; Among them, the vehicle state vector , representing idle speed, creep, constant speed, and full throttle acceleration conditions respectively. This vector is a one-hot vector, with one and only one value of 1 and the rest of them being 0; S2. Collect noise signals from the location of the error microphone inside the exhaust pipe and generate an error signal matrix. ; Among them, the error signal matrix L represents the number of residual noise signals collected from the pipeline; S3. Acquire engine crankshaft speed signal, process and generate narrowband reference signal matrix. Broadband reference signal ; S4, Narrowband Filter Coefficient Matrix Received via transfer function matrix Narrowband reference signal matrix for filtering and the aforementioned error noise matrix Adaptive coefficient update to generate the narrowband control signal matrix for the loudspeaker. ; Broadband filter coefficient matrix Received via transfer function matrix Filtered wideband reference signal matrix and the aforementioned error noise matrix Adaptive coefficient update to generate loudspeaker broadband control signal matrix ; S5, via vehicle state vector Determine the narrowband control signal matrix of the loudspeaker and broadband control signal matrix The operating state generates the final speaker control signal matrix. ; S6, Speaker Control Signal Matrix Through the transfer function matrix Secondary signal matrix generated at the location of the error microphone inside the exhaust pipe , and the primary noise matrix The noise is superimposed and canceled out, thereby achieving active noise control of the exhaust.

7. The method according to claim 6, characterized in that, In step S3, the narrowband reference signal matrix is ​​represented as follows: ； The broadband reference signal is represented as: ； in Z represents the frequency corresponding to the exhaust order noise to be controlled, and Z represents the number of exhaust order noise frequencies to be controlled.

8. The method according to claim 6, characterized in that, In step S4, the narrowband reference signal matrix It can be represented as: , ,in I is the length of the time-domain transfer function; Meanwhile, the narrowband filter coefficient matrix The update of the coefficients can be expressed as: , ,in This is the step size factor for the narrowband filter. This is the convergence factor of the narrowband filter; and the secondary speaker narrowband control signal matrix It can be represented as: ,in To correspond to the accumulation of reference signals at the current time and before I-1 time when the narrowband filter is operating, the symbol... This represents signal convolution.

9. The method according to claim 6, characterized in that, In step S4, the broadband reference signal matrix It can be represented as: , ,in , It is obtained by filtering the estimated value of the transfer function from the k-th vibration signal through the loudspeaker to the l-th error microphone; Broadband filter coefficient matrix The coefficients are updated, represented as follows: ,in This is the step size factor for the broadband filter. This is the step size factor for the broadband filter; Secondary speaker broadband control signal matrix It can be represented as: ,in This is to account for the accumulation of reference signals at the current time and before I-1 when the narrowband filter is in operation.

10. The method according to claim 6, characterized in that, In steps S5-S6: when the vehicle state is determined to be constant speed and full throttle, the speaker control signal matrix... ; When the vehicle status is determined to be idling or creeping, the speaker control signal matrix... Ultimately, , .

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