Method and system for reducing noise of engine in vehicle
By collecting and analyzing noise signals in the car and generating reverse sound waves with opposite phases, the problem of poor results of traditional noise reduction methods is solved, and effective engine noise reduction in the car is achieved, providing passengers with a quieter ride environment.
Patent Information
- Application Number
- CN202510358593.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-25
- Publication Date
- 2025-06-24
AI Technical Summary
The traditional method of reducing engine noise cannot achieve satisfactory noise reduction, mainly due to layout costs, material properties and structural design.
By setting up a noise collector in the vehicle ceiling, the original noise signal in the vehicle is collected, and combined with the vehicle operating conditions information, these signals are processed and analyzed, and sound waves with the opposite phase and the same amplitude as the original noise signal are generated, and the sound waves are output in the vehicle through the speakers to achieve mutual cancellation of noise.
Effectively reduce engine noise in the car, provide passengers with a quieter and more comfortable ride environment, and ensure the stability and optimization of noise reduction effect through real-time monitoring and dynamic adjustment.
Smart Images
Figure CN120199220A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical fields of NVH and electronic appliances, and particularly to a method and system for reducing engine noise in a vehicle. Background Art
[0002] With the rapid development of the automotive industry and the increasing improvement of people's living standards, cars have gradually become an indispensable means of transportation in people's daily lives. While enjoying the convenience and comfort brought by cars, people's requirements for the performance of cars are also increasing day by day. Among them, ride comfort has become one of the important considerations for consumers when choosing a car; Noise is one of the key factors affecting the ride comfort of cars. During the operation of a car, engine noise, as the most obvious component of vehicle noise, has a great impact on the riding experience of passengers in the car. Traditional methods for reducing engine noise mainly rely on using sound-absorbing and sound-insulating materials to reduce the engine noise from entering the car by absorption and blocking. However, this method has certain limitations in practical applications. Due to reasons such as layout costs, material properties, and structural design, traditional noise reduction methods often cannot achieve satisfactory noise reduction effects. In this regard, we propose a method for reducing engine noise in a vehicle. Summary of the Invention
[0003] To solve the above technical problems, a method and system for reducing engine noise in a vehicle are provided. This technical solution is used to solve the problem that traditional noise reduction methods often cannot achieve satisfactory noise reduction effects.
[0004] To achieve the above object, the technical solution adopted by the present invention is as follows: In the first aspect of the present invention, a method for reducing engine noise in a vehicle is provided, including: Four noise collectors are arranged in a closed sound-insulating pipe with one end open inside the vehicle roof to collect the original noise signal inside the vehicle; Obtain the vehicle operating condition information through the vehicle CAN bus, and the operating condition information includes: engine speed, vehicle speed, gear information; Based on the collected original noise signal and vehicle operating condition information, process and analyze the original noise signal and vehicle operating condition information to obtain the original noise signal sound wave information data; Based on the obtained original noise signal sound wave information data, the signal processor converts the original noise signal into a noise signal with the opposite phase, and amplifies the noise signal with the opposite phase through the power amplifier module to make its amplitude reach the amplitude of the original noise signal; The amplified noise signals with opposite phases are transmitted to the speaker, and the speaker outputs sound waves in the vehicle that are opposite in phase and equal in amplitude to the original noise signal, and the sound waves are transmitted to the passenger's ear area, so that the reverse sound waves transmitted to the passenger's ear area cancel out the original noise signal, achieving the effect of reducing the engine noise in the vehicle.
[0005] Preferably, four noise collectors are arranged in a closed sound insulation duct with one end open inside the vehicle roof. Collecting the original noise signal in the vehicle specifically includes: The arrangement position of the noise collector inside the vehicle roof is close to the passenger's head area, specifically directly above the position of the roof armrest. The distance requirement between it and the armrest position in the vertical direction is:
[0006] In the formula, h represents the vertical distance between the noise collector and the armrest position, and the unit is centimeter.
[0007] Preferably, the frequency response range of the noise collector is , and the sensitivity requirement is not less than -38dB (0dB = 1V / Pa).
[0008] Preferably, the processing and analysis of the original noise signal and the vehicle operating condition information specifically include: The collected original noise signal is filtered to remove high-frequency interference signals and low-frequency fluctuation signals. The Butterworth low-pass filter and high-pass filter are cascaded. The cut-off frequency of the low-pass filter is set to , and the cut-off frequency of the high-pass filter is set to ; Among them, for the Butterworth low-pass filter, its transfer function is:
[0009] In the formula, represents the transfer function of the filter in the complex frequency domain, s represents the complex variable, represents the cut-off angular frequency, , N represents the order of the filter; The original noise signal is input into this filter to obtain the low-pass filtered signal. The expression of the low-pass filtered signal is:
[0010] In the formula, represents the low-pass filtered signal, represents the inverse Laplace transform, represents the original noise signal of the Laplace transform; Among them, for the Butterworth high-pass filter, its transfer function is:
[0011] Wherein, represents the transfer function of the filter in the complex frequency domain, represents the cut-off angular frequency, ; Input the original noise signal into this filter to obtain the high-pass filtered signal, and the expression of the high-pass filtered signal is:
[0012] Wherein, represents the high-pass filtered signal, represents the low-pass filtered signal of the Laplace transform; Perform data verification on the vehicle operating condition information. If data anomalies are found, mark them as invalid data according to the vehicle's historical operating data and the preset normal operating condition range; Based on the noise feature extraction of the operating condition, obtain the engine fundamental frequency and the main harmonic frequencies according to the engine speed and gear information. The main harmonic frequencies are integer multiples of the fundamental frequency. Among them, the calculation formula for the engine fundamental frequency is:
[0013] Wherein, represents the engine fundamental frequency, n represents the engine speed, and z represents the number of engine cylinders; Integrate the extracted engine fundamental frequency and harmonic frequency components according to the time sequence and frequency distribution through short-time Fourier transform to construct the time-frequency representation of the original noise signal; Perform amplitude and phase analysis on the result of the short-time Fourier transform to obtain the amplitude and phase of each frequency component within each time segment, and record the corresponding engine speed, vehicle speed, and gear information; Combine these data into the original noise signal acoustic wave information data model, and the data model is represented as a multi-dimensional array:
[0014] Among them, represents the amplitude, represents the phase, represents the engine speed, represents the vehicle speed, represents the gear information, t represents the time index, and k represents the frequency component index.
[0015] Preferably, the output power of the power amplifier module is matched according to the size of the vehicle interior space and the required noise reduction effect; Let the volume of the vehicle interior space be V, and the output power of the power amplifier module be P, then when , ; The total harmonic distortion is:
[0016] Wherein, represents the amplitude of the k-th harmonic voltage, represents the amplitude of the fundamental voltage.
[0017] Preferably, four speakers are arranged in the vehicle, respectively located at the positions near the doors on the left and right sides of the front row of the vehicle and at the positions near the windows on the left and right sides of the rear row. The sound-emitting directions of the speakers are towards the ear regions of the passengers, and the pointing angle in the horizontal direction is , and the pointing angle in the vertical direction is .
[0018] Preferably, multiple noise monitoring sensors are arranged at different positions in the vehicle to monitor the noise reduction effect in real time. According to the monitoring results, the signal processor dynamically adjusts the parameters of the processing algorithm; When the noise reduction effect at a certain position is lower than the set threshold, increase the output power of the corresponding speaker in this area or adjust the signal phase. The threshold is set to 80% of the noise reduction amount lower than the expected noise reduction amount; Suppose the expected noise reduction amount at a certain position is , and the actual noise reduction amount is , then when , adjust the output power of the speaker:
[0019] Wherein, represents the adjusted power, represents the power before adjustment, and a represents the adjustment coefficient.
[0020] Preferably, when the engine control system detects that the engine is in a high-load operation state, it notifies the noise reduction system in advance to adjust the parameters. When the engine output torque exceeds 80% of the rated torque, the noise reduction system increases the signal acquisition frequency and processing speed.
[0021] Preferably, the noise reduction system is equipped with an independent power management module, which can automatically adjust the power consumption of the noise reduction system according to the vehicle battery power and the vehicle operation state; When the vehicle battery power is lower than 30% and the vehicle is in a parked or low-speed driving state, reduce the working frequency of the noise reduction system or some functions enter the sleep state to save power; When the vehicle battery is in the charging state and the power is higher than 80%, restore the noise reduction system to the best performance state.
[0022] Preferably, the software of the noise reduction system has an online upgrade function. It receives update data from the manufacturer's server through the vehicle's in-vehicle communication system. When the software is upgraded, the system automatically detects the compatibility with other vehicle electronic systems. If compatibility issues are found, it automatically rolls back to the previous stable version.
[0023] In the second aspect of the present invention, a system for reducing engine noise in a vehicle is provided, including a noise acquisition module, an operating condition information acquisition module, a preprocessing module, a noise signal amplification module, and a noise reduction module; The noise acquisition module includes four noise collectors disposed in a closed sound insulation pipe with one end open inside the vehicle roof to collect the original noise signal inside the vehicle; The operating condition information acquisition module obtains the vehicle operating condition information through the vehicle CAN bus. The operating condition information includes engine speed, vehicle speed, and gear information; The preprocessing module processes and analyzes the original noise signal and the vehicle operating condition information based on the collected original noise signal and vehicle operating condition information to obtain the acoustic wave information data of the original noise signal; The noise signal amplification module, based on the obtained acoustic wave information data of the original noise signal, the signal processor converts the original noise signal into a noise signal with the opposite phase, and amplifies the noise signal with the opposite phase through the in-vehicle power amplifier module to make its amplitude reach the amplitude of the original noise signal; The noise reduction module transmits the amplified noise signal with the opposite phase to the speaker, outputs an acoustic wave with the opposite phase and the same amplitude as the original noise signal inside the vehicle through the speaker, and transmits the acoustic wave to the passenger's ear area, so that the reverse acoustic wave transmitted to the passenger's ear area cancels out the original noise signal with each other, achieving the effect of reducing the engine noise inside the vehicle.
[0024] Compared with the prior art, the beneficial effects of the present invention are as follows: The present invention proposes a method for reducing engine noise in a vehicle. By accurately collecting the original noise signal inside the vehicle and combining the vehicle operating condition information, this method can generate an acoustic wave with the opposite phase and the same amplitude as the original noise signal, so as to achieve the mutual cancellation of noise in the passenger's ear area, effectively reduce the engine noise inside the vehicle, provide a more quiet and comfortable riding environment for passengers. By real-time monitoring the noise reduction effect and dynamically adjusting the processing algorithm parameters, it can ensure the stability and optimization of the noise reduction effect, realize the intelligentization of the noise reduction process, and can automatically adjust the power consumption according to the vehicle battery power and vehicle operating state, ensuring the noise reduction effect while also improving the energy utilization efficiency. BRIEF DESCRIPTION OF THE DRAWINGS
[0025] Figure 1 It is a flowchart of the method of the present invention. DETAILED DESCRIPTION OF THE INVENTION
[0026] The following description is used to disclose the present invention so that those skilled in the art can implement the present invention. The preferred embodiments in the following description are only examples, and those skilled in the art can think of other obvious variations.
[0027] Referring to Figure 1 as shown, a method for reducing engine noise in a vehicle includes: Four noise collectors are carefully arranged in a closed sound insulation duct with one end open inside the vehicle ceiling. Such an arrangement can effectively isolate the interfering noise in the external environment, ensuring that the noise collectors can accurately collect the original noise signals inside the vehicle. These noise collectors are precisely calibrated and have high sensitivity and wide-frequency response characteristics, capable of capturing noises of various frequencies, and can accurately collect low-frequency engine roars and mechanical vibration noises.
[0028] Through the vehicle's CAN bus, rich information about the vehicle's operating conditions can be obtained. This includes engine speed information, which reflects the working state of the engine, and different speeds will generate noises of different intensities and frequencies; vehicle speed information is also crucial, as changes in vehicle speed will cause changes in wind noise and the noise of tires rubbing against the road surface; gear information is closely related to the load and speed of the engine, and the engine's working state is different under different gears, resulting in different noises.
[0029] Based on the collected original noise signals and this detailed information about the vehicle's operating conditions, the signal processing system will conduct comprehensive and in-depth processing and analysis on them. First, the original noise signals are filtered and noise-reduced to remove the clutter and interference signals therein, so as to extract pure noise signals. Then, in combination with the vehicle's operating condition information, the characteristics and variation laws of the noises under different conditions are analyzed. Through complex algorithms and mathematical models, these data are processed and analyzed, and finally, the acoustic wave information data of the original noise signals are obtained, including the frequency, amplitude, and phase of the acoustic waves.
[0030] Based on the obtained acoustic wave information data of the original noise signals, a high-performance signal processor begins to play a key role. It precisely performs phase inversion processing on the original noise signals to make them into noise signals with opposite phases. This process requires highly precise calculation and processing capabilities to ensure that the phase of the inverted noise signal is exactly opposite to that of the original noise signal. Then, the noise signals with opposite phases are amplified through a powerful power amplifier module. The power amplifier module has high-power output and low-distortion characteristics and can amplify the noise signals to the same amplitude as the original noise signals. During the amplification process, the distortion degree of the signal is strictly controlled to ensure that the amplified signal is highly consistent with the original noise signal in amplitude and frequency.
[0031] The amplified noise signals with opposite phases are transmitted to high-quality speakers. The speakers are carefully selected and tuned to accurately output sound waves with the same amplitude as the original noise signals but in the opposite phase. These sound waves propagate inside the vehicle and are precisely transmitted to the area near the passengers' ears. At the area near the passengers' ears, the reverse sound waves meet the original noise signals. Since they have opposite phases and the same amplitude, they cancel each other out. This cancellation effect can effectively reduce the engine noise inside the vehicle, creating a quieter and more comfortable riding environment for passengers.
[0032] Four noise collectors are set in a closed sound-insulating duct with one end open inside the vehicle roof to collect the original noise signals inside the vehicle, specifically including: The layout positions of the noise collectors inside the vehicle roof are carefully considered. Specifically, they are deliberately chosen to be near the passengers' head areas. More precisely, they are arranged 0 to 15 centimeters directly above the position of the roof armrest. Such layout positions are of great significance. Being near the passengers' head areas can more accurately collect the actual noise conditions felt by the passengers. Since passengers' perception of noise mainly focuses around the head, arranging the noise collectors in this position can ensure that the collected noise signals are closest to the noise actually heard by the passengers, thus providing a more accurate data basis for subsequent noise reduction processing. Secondly, being arranged 0 to 15 centimeters directly above the position of the roof armrest neither interferes with the normal riding and activities of passengers nor takes up too much space inside the vehicle roof, achieving efficient noise collection without affecting the overall aesthetics and practicality of the vehicle. In addition, this position is relatively stable, with relatively less vibration and shaking during vehicle driving, which is conducive to the noise collectors maintaining a stable working state and ensuring the accuracy and reliability of the collected noise signals. The distance requirement between it and the armrest position in the vertical direction is:
[0033] In the formula, h represents the vertical distance between the noise collector and the armrest position, with the unit of centimeter.
[0034] The frequency response range of the noise collector is , this frequency range covers most of the sound frequencies that the human ear can perceive. Starting from the low 20Hz frequency, it can capture the low-frequency rumbling noise generated when the vehicle engine is running, as well as the low-frequency vibration noise caused by some large vehicles passing by. At the higher frequency end, the 20kHz frequency response upper limit can accurately collect various high-frequency noises generated during vehicle driving. The sensitivity requirement is not less than -38dB (0dB = 1V / Pa). Such a high sensitivity means that the noise collector can effectively detect and collect extremely weak noise signals. Even very slight noise fluctuations can be keenly captured by the noise collector and converted into electrical signals for subsequent processing and analysis, thus creating a more peaceful and comfortable riding environment for passengers.
[0035] The processing and analysis of the original noise signal and vehicle operating condition information specifically include: Perform detailed filtering on the collected original noise signal. This step is crucial. The purpose is to remove the high-frequency interference signals and low-frequency fluctuation signals in it. The high-frequency interference signals come from the environmental noise outside the vehicle, and these signals will interfere with the accurate analysis and processing of the in-vehicle noise. The low-frequency fluctuation signals are generated due to the vibration during vehicle driving or the unstable operation of the engine, and they will also affect the accuracy of the noise reduction system.
[0036] To achieve efficient filtering, a cascaded method of Butterworth low-pass filter and high-pass filter is adopted. The Butterworth filter has a flat passband response and a slow cut-off characteristic, which can minimize the signal distortion during filtering. The low-pass filter allows signals below a specific cut-off frequency to pass through while blocking signals above this cut-off frequency. By reasonably setting the cut-off frequency of the low-pass filter, the high-frequency interference signals can be effectively removed, and the useful low-frequency components in the in-vehicle noise can be retained.
[0037] On the contrary, the high-pass filter allows signals above a specific cut-off frequency to pass through while blocking signals below this cut-off frequency. By cascading the high-pass filter with the low-pass filter, the low-frequency fluctuation signals in the original noise signal can be removed, and the useful high-frequency components can be retained. This cascaded method can achieve comprehensive filtering of the original noise signal, remove unnecessary interference signals, and provide a cleaner signal for subsequent noise analysis and processing.
[0038] When the vehicle is driving on noisy urban roads, the surrounding environmental noise contains a large number of high-frequency components. The low-pass filter can filter out these high-frequency interference signals, making the subsequent processed signals cleaner. At the same time, the vehicle engine generates some low-frequency fluctuations during startup and operation. The high-pass filter can remove these low-frequency fluctuation signals to ensure that the noise reduction system can accurately process the main noise components inside the vehicle. By cascading this Butterworth low-pass filter and high-pass filter, the performance of the noise reduction system can be effectively improved, providing a quieter riding environment for passengers. The cut-off frequency of the low-pass filter is set to , and the cut-off frequency of the high-pass filter is set to ; Among them, for the Butterworth low-pass filter, its transfer function is:
[0039] In the formula, represents the transfer function of the filter in the complex frequency domain, s represents the complex variable, represents the cut-off angular frequency, , and N represents the filter order; Input the original noise signal into this filter to obtain the low-pass filtered signal. The expression of the low-pass filtered signal is:
[0040] In the formula, represents the low-pass filtered signal, represents the inverse Laplace transform, represents the original noise signal 's Laplace transform; Among them, for the Butterworth high-pass filter, its transfer function is:
[0041] In the formula, represents the transfer function of the filter in the complex frequency domain, represents the cut-off angular frequency, ; Input the original noise signal into this filter to obtain the high-pass filtered signal. The expression of the high-pass filtered signal is:
[0042] In the formula, represents the high-pass filtered signal, represents the Laplace transform of the low-pass filtered signal ; Perform data verification on the vehicle operating condition information. If data anomalies are found, mark them as invalid data based on the vehicle's historical operating data and the preset normal operating condition range; During the process of extracting noise characteristics based on the operating conditions, make full use of the engine speed and gear information to obtain the engine fundamental frequency and the main harmonic frequencies. When the engine operates at different speeds and gears, specific frequency characteristics will be generated. By analyzing this information, the engine fundamental frequency can be accurately determined. The main harmonic frequencies are usually integer multiples of the fundamental frequency, which is determined by the engine's working principle. Among them, the formula for calculating the engine fundamental frequency is:
[0043] In the formula, represents the engine fundamental frequency, n represents the engine speed, and z represents the number of engine cylinders; Integrate the extracted engine fundamental frequency and harmonic frequency components according to the time sequence and frequency distribution through the short-time Fourier transform. The short-time Fourier transform is a powerful signal processing tool that can analyze the signal in both the time and frequency dimensions. Integrating according to the time sequence can observe the change of the noise signal over time; while integrating according to the frequency distribution can clearly see the distribution of different frequency components in the entire signal. In this way, a time-frequency representation of the original noise signal is constructed, providing comprehensive information for subsequent analysis and processing.
[0044] Performing amplitude and phase analysis on the result of the short-time Fourier transform is a crucial step. Through the analysis, the amplitude and phase of each frequency component within each time segment can be obtained. The amplitude represents the intensity of the signal, and the phase reflects the relative position of the signal. At the same time, record the corresponding engine speed, vehicle speed, and gear information, which helps to establish the relationship between the noise signal and the vehicle operating conditions. For example, when the engine speed increases, the amplitude of some frequency components will increase, and the phase will also change. By recording this information, the change law of the noise signal can be better understood.
[0045] Combine these data into the original noise signal acoustic wave information data model. This data model is represented as a multi-dimensional array, which contains time, frequency, amplitude, phase, as well as engine speed, vehicle speed, and gear. Such a multi-dimensional array can comprehensively describe the characteristics of the original noise signal, providing a rich data basis for subsequent noise reduction processing. By analyzing this multi-dimensional array, determine the parameters of the reverse noise signal to be generated under different operating conditions to achieve a more accurate noise reduction effect. The data model is represented as a multi-dimensional array:
[0046] Among them, represents the amplitude, represents the phase represents the engine speed represents the vehicle speed represents the gear information, t represents the time index, and k represents the frequency component index
[0047] The output power of the power amplifier module is matched according to the size of the vehicle interior space and the required noise reduction effect Let the volume of the vehicle interior space be V and the output power of the power amplifier module be P. Then when , ; The total harmonic distortion is
[0048] In the formula represents the amplitude of the k-th harmonic voltage represents the amplitude of the fundamental voltage
[0049] Four speakers are arranged inside the vehicle, located on the left and right sides of the front row of the vehicle near the door positions and on the left and right sides of the rear row near the window positions. The sound emission direction of the speakers faces the ear area of the passengers, aiming to provide the best noise reduction experience for the passengers. The sound emission direction of the speakers is precisely adjusted to face the ear area of the passengers to ensure that the reverse sound waves can accurately reach near the ears of the passengers, achieving the most effective noise cancellation. The pointing angle in the horizontal direction is , and this angle range can minimize the unnecessary influence on other areas while ensuring coverage of the ear area of the passengers. When the passenger is sitting in the left front position of the vehicle, the speaker on that side can accurately focus the reverse sound waves near the ear of the passenger by adjusting the horizontal pointing angle without excessive diffusion to other areas of the vehicle, thereby improving the pertinence and effect of noise reduction. The pointing angle in the vertical direction is , and this angle setting is also to better adapt to the ear position of the passengers to ensure that the reverse sound waves can be transmitted to the ears of the passengers at the best angle. Whether the passenger is in a normal sitting position or slightly adjusting the sitting position, the vertical pointing angle of the speaker can ensure the effectiveness of the reverse sound waves
[0050] In order to monitor the noise reduction effect in real time, multiple noise monitoring sensors are set at different positions inside the vehicle. These sensors are distributed at various key positions inside the vehicle and can comprehensively detect the noise level inside the vehicle. Through real-time monitoring, the working state of the noise reduction system and the noise reduction effect in different areas can be understood in a timely manner
[0051] Based on the monitoring results, the signal processor will dynamically adjust the parameters of the processing algorithm. If the noise level in a certain area is high, or the noise reduction effect is not ideal, the signal processor will automatically analyze the monitoring data and adjust the parameters of the processing algorithm. The amplitude and phase parameters of the generated anti-noise signal will be adjusted to improve the noise reduction effect in that area.
[0052] When the noise reduction effect at a certain position is lower than the set threshold, the system will take corresponding measures for adjustment. Here, the threshold is set to 80% of the expected noise reduction amount. If the noise reduction effect at a certain position fails to meet this standard, the system will first consider increasing the output power of the corresponding speaker in that area. By increasing the output power of the speaker, the intensity of the reverse sound wave can be enhanced, thus better canceling the original noise signal. In addition, the system can also adjust the phase of the signal to ensure that the reverse sound wave is exactly opposite in phase to the original noise signal, achieving more effective noise cancellation.
[0053] For example, when the vehicle is driving on a rough road, due to the road surface bumps, the noise level inside the vehicle will change. At this time, the noise monitoring sensor will detect the noise change in real time and transmit the data to the signal processor. If the noise reduction effect in a certain area is lower than the set threshold, the system will take measures such as increasing the output power or adjusting the signal phase according to the specific situation to ensure that the noise reduction effect inside the vehicle is always good; Let the expected noise reduction amount at a certain position be , and the actual noise reduction amount be , then when , the output power of the speaker is adjusted as follows:
[0054] In the formula, represents the adjusted power, represents the power before adjustment, and a represents the adjustment coefficient.
[0055] When the engine control system plays its important role and detects that the engine is in a high-load operating state, it will immediately notify the noise reduction system in advance to prepare for parameter adjustment. Specifically, when the engine output torque exceeds 80% of the rated torque, this means that the engine is under a large load. At this time, the noise reduction system will quickly respond by increasing the signal acquisition frequency and processing speed. By increasing the signal acquisition frequency, the noise changes generated during the high-load operation of the engine can be captured more timely, providing more accurate data for subsequent noise reduction processing. At the same time, accelerating the processing speed can ensure that the noise reduction system analyzes and processes the collected noise signals within a short time to generate effective reverse sound waves to cope with the noise challenges brought by the high-load operation of the engine.
[0056] The noise reduction system is equipped with an independent power management module, which plays a crucial role. It can automatically adjust the power consumption of the noise reduction system according to the vehicle battery power and the vehicle operating state. For example, when the vehicle battery power is below 30% and the vehicle is in a parked or low-speed driving state, in order to save power, the power management module will reduce the operating frequency of the noise reduction system or put some functions into the sleep state. In this case, the noise reduction system will give priority to ensuring the power required for the basic driving functions of the vehicle while trying to reduce its own power consumption. Some functions entering the sleep state can temporarily turn off some less critical noise reduction processing links, or reduce the working intensity of certain modules to reduce the overall power consumption. And when the vehicle battery is in the charging state and the power is above 80%, the power management module will promptly restore the noise reduction system to the optimal performance state. At this time, the noise reduction system can fully exert its powerful noise reduction function to provide a more quiet and comfortable riding environment for passengers.
[0057] In addition, the software of the noise reduction system has an online upgrade function. Through the vehicle's in-vehicle communication system, the noise reduction system can receive update data from the manufacturer's server. This enables the noise reduction system to continuously optimize and improve its performance to adapt to the changing vehicle operating environment and user needs. When the software is upgraded, the system will automatically detect the compatibility with other vehicle electronic systems. This is a very important step because there are many electronic systems in the vehicle, and compatibility issues between different systems will affect the overall performance and stability of the vehicle. If the system detects compatibility issues, it will automatically roll back to the previous stable version to ensure the normal operation of the vehicle. Such a design not only ensures that the noise reduction system can continuously improve its performance but also avoids potential risks caused by software upgrades.
[0058] The usage process of the present invention is as follows: Set up a noise collector to collect the original noise inside the vehicle, obtain the vehicle operating condition information through the CAN bus, process and analyze the original noise signal and the condition information, convert the original noise signal into a signal with the opposite phase and amplify it, and output the amplified reverse noise signal through the speaker.
[0059] In another embodiment of the present invention, a system for reducing engine noise inside the vehicle is provided, including a noise collection module, an operating condition information collection module, a preprocessing module, a noise signal amplification module, and a noise reduction module; The noise collection module includes four noise collectors arranged in a closed sound insulation duct with one end open inside the vehicle roof to collect the original noise signal inside the vehicle; The operating condition information collection module obtains the vehicle operating condition information through the vehicle CAN bus, and the operating condition information includes: engine speed, vehicle speed, gear information; A preprocessing module, based on the collected original noise signal and vehicle operating condition information, processes and analyzes the original noise signal and vehicle operating condition information to obtain the original noise signal acoustic wave information data; A noise signal amplification module, based on the obtained original noise signal acoustic wave information data, the signal processor converts the original noise signal into a noise signal with the opposite phase, and amplifies the noise signal with the opposite phase through the power amplifier module in the vehicle to make its amplitude reach the amplitude of the original noise signal; A noise reduction module transmits the amplified noise signal with the opposite phase to the speaker, outputs an acoustic wave with the opposite phase and the same amplitude as the original noise signal in the vehicle through the speaker, and transmits the acoustic wave to the passenger's ear area, so that the reverse acoustic wave transmitted to the passenger's ear area cancels out the original noise signal, achieving the effect of reducing the engine noise in the vehicle.
[0060] In summary, the advantages of the present invention are as follows: accurately collect the original noise signal in the vehicle and combine the vehicle operating condition information to generate an acoustic wave with the opposite phase and the same amplitude as the original noise signal to cancel the noise, providing a quiet and comfortable riding environment for passengers. Real-time monitor the noise reduction effect and dynamically adjust the processing algorithm parameters to achieve intelligent noise reduction. It can also automatically adjust the power consumption according to the vehicle battery power and operating state, improving the energy utilization efficiency.
[0061] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. What is described in the above embodiments and the specification is only the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed. The scope of protection claimed by the present invention is defined by the appended claims and their equivalents.
Claims
1. A method for reducing engine noise in a vehicle, characterized in that: include: Four noise collectors are placed in a closed soundproof pipe with one end open inside the roof of the vehicle to collect the original noise signal inside the vehicle; Obtaining vehicle operating condition information through the vehicle CAN bus, the operating condition information including engine speed, vehicle speed, and gear position information; Based on the collected original noise signal and the vehicle operating condition information, the original noise signal and the vehicle operating condition information are processed and analyzed to obtain the original noise signal sound wave information data; Based on the obtained sound wave information data of the original noise signal, the signal processor converts the original noise signal into a noise signal with an opposite phase, and amplifies the noise signal with an opposite phase through the power amplifier module in the vehicle so that its amplitude reaches the amplitude of the original noise signal; The amplified noise signal with opposite phase is transmitted to the speaker, which outputs a sound wave with opposite phase and the same amplitude as the original noise signal in the car, and transmits the sound wave to the passenger's ear area, so that the reverse sound wave transmitted to the passenger's ear area and the original noise signal cancel each other out, thereby achieving the effect of reducing the engine noise in the car.
2. A method for reducing engine noise in a vehicle according to claim 1, characterized in that: Four noise collectors are placed in a closed soundproof pipe with one end open in the roof of the vehicle to collect the original noise signal inside the vehicle, including: The noise collector is arranged in the vehicle ceiling close to the passenger head area, specifically just above the ceiling handrail. The vertical distance requirement between the noise collector and the handrail is: Where h is the vertical distance between the noise collector and the handrail, in centimeters.
3. The method for reducing engine noise in a vehicle according to claim 1, characterized in that: The frequency response range of the noise collector is , the sensitivity requirement is not less than -38dB (0dB=1V / Pa).
4. The method for reducing engine noise in a vehicle according to claim 1, characterized in that: The processing and analysis of the original noise signal and vehicle operating condition information specifically include: The collected original noise signal is filtered to remove high-frequency interference signals and low-frequency fluctuation signals. The Butterworth low-pass filter and high-pass filter are cascaded, and the cutoff frequency of the low-pass filter is set to , the high-pass filter cutoff frequency is set to ; Among them, the transfer function of the Butterworth low-pass filter is: In the formula, represents the transfer function of the filter in the complex frequency domain, s represents a complex variable, represents the cut-off angular frequency, , N represents the filter order; The original noise signal is input into the filter to obtain the signal after low-pass filtering, where the expression of the signal after low-pass filtering is: In the formula, represents the signal after low-pass filtering, represents the inverse Laplace transform, Represents the original noise signal The Laplace transform of Among them, the Butterworth high-pass filter has a transfer function of: In the formula, represents the transfer function of the filter in the complex frequency domain, represents the cut-off angular frequency, ; The original noise signal is input into the filter to obtain the signal after high-pass filtering, where the expression of the signal after high-pass filtering is: In the formula, represents the signal after high-pass filtering, Represents the signal after low-pass filtering The Laplace transform of Perform data verification on the vehicle operating condition information. If any data abnormality is found, it will be marked as invalid data based on the vehicle's historical operating data and the preset normal operating condition range; Based on the noise feature extraction of the operating conditions, the engine fundamental frequency and main harmonic frequency are obtained according to the engine speed and gear information. The main harmonic frequency is an integer multiple of the fundamental frequency. The engine fundamental frequency calculation formula is: In the formula, represents the engine base frequency, n represents the engine speed, and z represents the number of engine cylinders; The extracted engine fundamental frequency and harmonic frequency components are integrated according to the time sequence and frequency distribution through short-time Fourier transform to construct the time-frequency representation of the original noise signal; Perform amplitude and phase analysis on the results of short-time Fourier transform to obtain the amplitude and phase of each frequency component in each time segment, and record the corresponding engine speed, vehicle speed and gear information; Combine these data into the original noise signal sound wave information data model, which is represented by a multidimensional array: in, represents the amplitude, Indicates the phase, Indicates the engine speed, Indicates vehicle speed. represents the gear information, t represents the time index, and k represents the frequency component index.
5. The method for reducing engine noise in a vehicle according to claim 1, characterized in that: The output power of the power amplifier module is matched according to the size of the vehicle's interior space and the required noise reduction effect; Assume that the volume of the vehicle interior is V and the output power of the power amplifier module is P. , ; The total harmonic distortion is: In the formula, represents the kth harmonic voltage amplitude, Indicates the fundamental voltage amplitude.
6. The method for reducing engine noise in a vehicle according to claim 1, characterized in that: Four speakers are arranged in the car, located on the left and right sides of the front row near the door and the left and right sides of the rear row near the window. The sound direction of the speakers is toward the passenger ear area, and its horizontal pointing angle is , the vertical direction angle is .
7. The method for reducing engine noise in a vehicle according to claim 1, characterized in that: Multiple noise monitoring sensors are set up at different locations in the car to monitor the noise reduction effect in real time. Based on the monitoring results, the signal processor dynamically adjusts the parameters of the processing algorithm; When the noise reduction effect at a certain location is lower than the set threshold, increase the output power of the corresponding speaker in that area or adjust the signal phase. The threshold is set to 80% of the noise reduction amount that is lower than the expected noise reduction amount; Assume that the expected noise reduction at a certain location is , the actual noise reduction is , then when When the speaker output power is adjusted: In the formula, represents the adjusted power, It is expressed as the power before adjustment, and a is the adjustment coefficient.
8. The method for reducing engine noise in a vehicle according to claim 1, characterized in that: When the engine control system detects that the engine is in a high-load operating state, it notifies the noise reduction system in advance to adjust the parameters. When the engine output torque exceeds 80% of the rated torque, the noise reduction system increases the signal acquisition frequency and processing speed.
9. The method for reducing engine noise in a vehicle according to claim 1, characterized in that: The noise reduction system is equipped with an independent power management module, which can automatically adjust the power consumption of the noise reduction system according to the vehicle battery power and vehicle operating status; When the vehicle battery power is less than 30% and the vehicle is parked or driving at a low speed, the noise reduction system will reduce its operating frequency or some functions will enter a dormant state to save power; When the vehicle battery is charged and the power level is above 80%, the noise reduction system is restored to optimal performance.
10. A system for reducing engine noise in a vehicle, characterized in that: It includes a noise collection module, an operating condition information collection module, a preprocessing module, a noise signal amplification module and a noise reduction module; The noise collection module includes four noise collectors arranged in a closed soundproof pipe with one end open in the roof of the vehicle to collect the original noise signal in the vehicle; The operating condition information acquisition module obtains the vehicle operating condition information through the vehicle CAN bus, and the operating condition information includes engine speed, vehicle speed, and gear position information; A preprocessing module processes and analyzes the original noise signal and the vehicle operating condition information based on the collected original noise signal and the vehicle operating condition information to obtain the original noise signal sound wave information data; The noise signal amplification module converts the original noise signal into a noise signal with an opposite phase based on the obtained sound wave information data of the original noise signal by the signal processor, and amplifies the noise signal with an opposite phase through the power amplifier module in the vehicle to make its amplitude reach the amplitude of the original noise signal; The noise reduction module transmits the amplified noise signal with opposite phase to the speaker, which outputs a sound wave with opposite phase and the same amplitude as the original noise signal in the car, and transmits the sound wave to the passenger's ear area, so that the reverse sound wave transmitted to the passenger's ear area and the original noise signal cancel each other out, thereby achieving the effect of reducing the engine noise in the car.