CN102175299A - Method and system for measuring noise frequency response function - Google Patents
Method and system for measuring noise frequency response function Download PDFInfo
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- CN102175299A CN102175299A CN2011100227505A CN201110022750A CN102175299A CN 102175299 A CN102175299 A CN 102175299A CN 2011100227505 A CN2011100227505 A CN 2011100227505A CN 201110022750 A CN201110022750 A CN 201110022750A CN 102175299 A CN102175299 A CN 102175299A
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- 238000005316 response function Methods 0.000 title claims abstract description 33
- 238000000034 method Methods 0.000 title claims abstract description 23
- 238000005259 measurement Methods 0.000 claims abstract description 15
- 230000005284 excitation Effects 0.000 claims description 20
- 230000007246 mechanism Effects 0.000 claims description 6
- 239000011810 insulating material Substances 0.000 claims description 5
- 238000013461 design Methods 0.000 claims description 4
- 239000002184 metal Substances 0.000 claims description 3
- 239000011148 porous material Substances 0.000 claims description 3
- 238000001228 spectrum Methods 0.000 claims description 3
- 238000005314 correlation function Methods 0.000 claims description 2
- 238000012360 testing method Methods 0.000 abstract description 23
- 238000011161 development Methods 0.000 abstract description 3
- 238000012545 processing Methods 0.000 abstract description 3
- 230000000694 effects Effects 0.000 description 8
- 230000008030 elimination Effects 0.000 description 7
- 238000003379 elimination reaction Methods 0.000 description 7
- 230000008569 process Effects 0.000 description 7
- 230000003584 silencer Effects 0.000 description 6
- 230000005540 biological transmission Effects 0.000 description 4
- 238000010998 test method Methods 0.000 description 4
- 238000006243 chemical reaction Methods 0.000 description 3
- 230000003750 conditioning effect Effects 0.000 description 2
- 230000008676 import Effects 0.000 description 2
- 238000003780 insertion Methods 0.000 description 2
- 230000037431 insertion Effects 0.000 description 2
- 238000004451 qualitative analysis Methods 0.000 description 2
- 238000004364 calculation method Methods 0.000 description 1
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- 238000010276 construction Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 230000036541 health Effects 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 238000005086 pumping Methods 0.000 description 1
- 230000004044 response Effects 0.000 description 1
- 238000007789 sealing Methods 0.000 description 1
- 230000005236 sound signal Effects 0.000 description 1
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Abstract
The invention discloses a method and system for measuring a noise frequency response function. The method is used for testing the sound pressures at the inlet and outlet of a tested part and performing the ratio operation on the sound pressures so as to acquire a frequency response function curve of the tested part, thereby showing the noise feature of the tested part based on the frequency response function curve. The measuring system comprises the tested part, a measuring device used for measuring noise signals, a noise signal source and a tail pipe, wherein the noise signal source and the tail pipe are respectively arranged at two ends of the tested part; the measuring device used for measuring the noise signals comprises a first microphone arranged at the outlet of the noise signal source and a second microphone arranged on the tail pipe; and the output signals of the first and second microphones are connected to a noise data processing system. The measuring method provided by the invention is reasonable, simple and convenient, and high in measuring efficiency. The measurement in an anechoic chamber is not required, the demand on the external environment is lower, and the experimental cost is low. The adopted device is simple in structure and convenient to operate. The development period of parts can be shortened and the development cost can be saved. The method and system provided by the invention are suitable for noise measurement on parts of air-intake exhaust systems of various cars.
Description
Technical field
The present invention relates to a kind of noise measurement system and measuring method, specifically relate to a kind of automobile air inlet system and exhaust system parts noise frequency response function measuring system and method.
Background technology
Along with the requirement of consumer to driver comfort, each big motor corporation more and more payes attention to automobile NVH (Noise, Vibration, Harshness) performance.In the noise of car load, under the low vehicle speed condition, the contribution of noise maximum derives from the air inlet system and exhaust system of motor car engine.
At present, the noise rating at automobile air inlet system and exhaust system or parts generally is to lose by transmission loss or the insertion of testing this system or part.Transmission loss can be estimated independent silencer element noise elimination effect, can analyze silencer element in each frequency noise elimination effect,, when anechoic room is done this test, need standing wave tube to be installed at afterbody if need to measure the parts effect of eliminating the noise accurately, it is bigger to take up room, and experimentation cost is higher.The measurement of transmission loss is to calculate the difference of acoustical power by surveying tested part import and export acoustic pressure, need before and after tested part 2 microphones be installed respectively at least, and complicated operation calculates loaded down with trivial details.
The test of inserting loss is a noise elimination effect of measuring whole air inlet system and exhaust system on car load, and test operation is loaded down with trivial details.This test is measured at twice, measures respectively sound-attenuating system and the noise acoustic pressure of not installing under the sound-attenuating system installation pipeline situation are installed, and the acoustic pressure of calculating twice is poor.Need to measure after the engine start, test operation is more loaded down with trivial details.This test effect on the whole air inlet system and exhaust system of evaluation is better, but can't estimate the noisiness of single silencer element separately.
Summary of the invention
The measuring method and the measuring system that the purpose of this invention is to provide a kind of noise frequency response function, solve the sky high cost and the complicated operations of present transmission loss method of testing, and solve the loaded down with trivial details of insertion loss method of testing, and insert the problem that loss can't be tested the parts noisiness separately.The employed equipment cost of measuring method of the present invention is cheap, and is easy to operate, the acoustic characteristics of qualitative analysis silencer element fast, and the frequency response function curve that draws is accurately reliable.
The present invention for realizing the technical scheme that its purpose adopts is: a kind of measuring method of noise frequency response function may further comprise the steps:
Steps A, measure tested part respectively in the acoustic pressure at different frequency lower inlet place and the acoustic pressure in exit simultaneously;
Step B, the acoustic pressure of inflow point and the acoustic pressure in exit are carried out the ratio computing during to same frequency;
The acoustic pressure of the inflow point of step C, comprehensive whole measurement frequency band and the acoustic pressure in exit are carried out the frequency response function curve that ratio obtains the part of surveying.
Further, in the measuring method of above-mentioned a kind of noise frequency response function: among the described step B, the ratio computing is exactly the cross correlation function of the acoustic pressure in the acoustic pressure at time domain lower inlet place and exit, obtains cross-power spectrum under the frequency through the variation of FFT then.
Another object of the present invention provides a kind of measuring system of noise frequency response function, and this system equipment is with low cost, and is easy to operate, the acoustic characteristics of qualitative analysis silencer element fast, and the frequency response function curve that draws is accurately reliable.Measuring system comprises tested part, measures measurement mechanism, noise signal source and the tail pipe of noise signal, described noise signal source and tail pipe are separately positioned on the two ends of tested part, the measurement mechanism of described measurement noise signal comprises first microphone of the outlet that is arranged on described noise signal source and is arranged on second microphone at tail pipe place that the output signal of described first microphone and second microphone is connected with the noise data disposal system.Finish in described noise data disposal system the output signal of described first microphone and the output signal of second microphone are carried out the ratio computing, obtain the frequency response function curve of described tested part.
Further, in the measuring system of above-mentioned a kind of noise frequency response function: described noise data disposal system comprises: power amplifier, A/D transducer, be equipped with and finish the computer that two groups of data are carried out the ratio computing and shown the noise software of frequency response function curve, the output signal of the output signal of described first microphone and second microphone is amplified into the A/D transducer through power amplifier respectively and converts digital signal to, and digital signal is input in the computer and handles.
Further, in the measuring system of above-mentioned a kind of noise frequency response function: described noise signal source comprises white noise, pink noise, sinusoidal signal and four kinds of basic sound sources of 20-2000Hz swept-frequency signal.
Further, in the measuring system of above-mentioned a kind of noise frequency response function: described noise signal source comprises excitation sound source and power amplifier, and the output of described excitation sound source connects power amplifier, and the output of power amplifier connects the tested part front end.Described excitation sound source adopts two cast-in-block metal shells, and the sounding end is a horn designs, inner filling porous material parcel pronunciation loudspeaker.
Further, in the measuring system of above-mentioned a kind of noise frequency response function: described tested part, the junction of measuring measurement mechanism, noise signal source and the tail pipe of noise signal all use the porous sound insulating material to seal.
Good effect of the present invention is that the employing method of testing is rationally easy, testing efficiency is high; Do not need in the anechoic room test, environmental requirement is lower to external world; Experimentation cost is low, and institute's employing device structure is simple, and is easy to operate.Can shorten the part construction cycle, save cost of development, be applicable to each vehicle air inlet system and exhaust system parts noiseproof feature exploitation.
Below by in conjunction with specific embodiments with accompanying drawing, technical scheme of the present invention is carried out comparatively detailed description.
Description of drawings
Fig. 1 is the synoptic diagram of the embodiment of the invention 1 measuring system.
Fig. 2 is the coherence function of the embodiment of the invention 1 test.
Fig. 3 is the result that the embodiment of the invention 1 is measured.
Embodiment
Embodiment 1: the measuring method and the measuring process that are a kind of measuring system of noise frequency response function as shown in Figure 1.The present invention proposes a kind of new method of testing, the acoustic pressure of test tested part import and export is carried out the frequency response function curve that the ratio computing obtains the part of surveying to acoustic pressure, the noisiness of tested part as can be seen from the frequency response function curve.Present embodiment is used following equipment: the noise data acquisition system, measure the microphone of noise signal, the notebook of noise software or other computer, power amplifier, excitation sound source, tail pipe be installed.The noise software that present embodiment uses is conventional noise software, is provided by Saic Chery Automobile Co., Ltd, and its dbase is RFR test.9A.Noise data acquisition system output terminal links to each other with the power amplifier input end, and the power amplifier output terminal links to each other with the excitation sound source, and the voice signal that notebook sends is through power amplifier conditioning rear drive excitation sound source.Microphone links to each other with the data acquisition system (DAS) input end, and microphone signal is sent in the notebook after being handled by data acquisition system (DAS), by the data acquisition system (DAS) software processes.
Carry out the processing of following steps by software in data acquisition system (DAS):
Steps A, measure tested part respectively in the acoustic pressure at different frequency lower inlet place and the acoustic pressure in exit simultaneously;
Step B, the acoustic pressure of inflow point and the acoustic pressure in exit are carried out the ratio computing during to same frequency; Here, the ratio computing is exactly the cross correlation function of the acoustic pressure in the acoustic pressure at time domain lower inlet place and exit, obtains cross-power spectrum under the frequency domain through the variation of FFT then.
The acoustic pressure of the inflow point of step C, comprehensive whole measurement frequency band and the acoustic pressure in exit are carried out the frequency response function curve that ratio obtains the part of surveying.
Sound stimulation adopts power amplifier, excitation sound source in the present embodiment, and the acoustical signal of excitation usefulness adopts the swept-frequency signal of software processes.Connect data acquisition system (DAS), microphone, notebook, power amplifier and excitation sound source by the high-performance shielded cable.The selection of sound source is according to the 4 kinds of basic sound sources that need of test; Be integrated with 4 kinds of basic sound sources in the present embodiment: 1, white noise, 2, pink noise, 3, sinusoidal signal, 4, the 20-2000Hz swept-frequency signal.The excitation sound source adopts two cast-in-block metal shells, the sounding end is a conical design, inner filling porous material parcel pronunciation loudspeaker, excitation sound source and tested part, tested part and tail pipe junction, microphone bearing adopt the sound insulating material parcel, and these designs can completely cut off the influence of external sound signal to the test macro accuracy greatly.
At excitation sound source sounding mouth place a microphone is installed during test, a microphone is installed at the tail pipe place behind the silencer element.Microphone with the tail pipe place is reference, uses the microphone at sound source sounding mouth place to respond, and with data acquisition software sound pressure signal is carried out ratio calculation, can obtain the frequency response function curve of this tested part.No matter be single-frequency or other signals, the calculating of carrying out in computing machine in the present embodiment all is the cross-power spectrum of input noise in output noise.And the conversion that input noise signal and output noise signal need not to compose separately.Can directly find out the frequency characteristic of tested part from the curve, peak value place frequency is exactly the best frequency of this tested part noise elimination effect, can be used to verify whether the frequency of noise elimination of noise elimination part meets the requirements.
Structural representation as shown in Figure 1 filters the excitation sound source 1 that is input to noise signal after amplifier is nursed one's health through the frequency sweep voice signal process that software processes is crossed.1 outlet of excitation sound source is connected with tested part 2, and measured device is the exhaust box of automobile in the present embodiment.Tested part 2 other ends are connected with tail pipe 3.Each junction seals with the porous sound insulating material.Tail pipe 3 directions are pointed to spacious place, to avoid reecho interference test result.First microphone 4 and second microphone 5 are installed in exhaust box and excitation sound source 1 and exhaust box and tail pipe 3 junctions respectively.Handle in the data acquisition system (DAS) software of the voice signal that collects on notebook, the signal that second microphone 5 collects as a reference, the signal that first microphone 4 collects is as excitation, the curve that obtains is exactly the frequency response curve of tested part.
Test process is as follows:
1, connects power amplifier and data acquisition system (DAS), connect the sound-source signal line, connect the excitation sound source 1 and tested part 2 (as mobile muffler) of noise signal, connect mobile muffler and tail pipe 3 to power amplifier.Install first microphone 4 and second microphone 5 respectively.Disturb to prevent external sound with the sound insulating material sealing all junctions.
When 2, testing, start voice signal software, the voice signal that sends is the input stimulus sound source after the power amplifier conditioning, and first microphone 4 is gathered the sound after sound sources, the 5 process exhaust box conversion of second microphone.The voice signal of first microphone 4 and second microphone 5 is input to data acquisition system (DAS).The signal of gathering with second microphone 5 at tail pipe 3 places is as the reference signal, the voice signal that first microphone 4 is gathered compares the frequency response function curve that processing promptly obtains required tested part 2 (being exhaust box) as pumping signal in the data acquisition system (DAS) software of notebook.Peak of curve place frequency is exactly the frequency that tested part (exhaust box) mainly works, and the peak value size is represented the noise elimination effect size of this frequency qualitatively.
Fig. 2 is the coherence function of test result, is the function of input noise under the frequency domain of the related function (statistical function of time domain) of output noise, is coherence function, and it is the accuracy of the frequency response function of reaction test.The coherence is that 1 explanation output is caused by input fully, can fully believe the measurement result of frequency response function.As can be seen from the figure the above coherence function value of 50Hz is all more than 0.9, and measurement result is very accurate.
Fig. 3 is the frequency response function of this tested part, shows among the figure that it mainly eliminates the noise the zone near 166Hz.This figure is that a kind of custom shows.In fact with importing, be a kind of problem of seeing drawing method of custom than last output or with exporting than last input.Provide two kinds to see drawing method in the present embodiment, actual test also can be selected in calculating.No matter be the input than last output or output than last input, can not change the characteristic of system under test (SUT), also all be frequency response function.The method difference of seeing of the curve that just obtains.
Claims (8)
1. the measuring method of a noise frequency response function may further comprise the steps:
Steps A, measure tested part respectively in the acoustic pressure at different frequency lower inlet place and the acoustic pressure in exit simultaneously;
Step B, the acoustic pressure of inflow point and the acoustic pressure in exit are carried out the ratio computing during to same frequency;
The acoustic pressure of the inflow point of step C, comprehensive whole measurement frequency band and the acoustic pressure in exit are carried out the frequency response function curve that ratio obtains the part of surveying.
2. the measuring method of a kind of noise frequency response function according to claim 1, it is characterized in that: among the described step B, the ratio computing is exactly the cross correlation function of the acoustic pressure in the acoustic pressure at time domain lower inlet place and exit, obtains cross-power spectrum under the frequency through the variation of FFT then.
3. measuring system that realizes noise frequency response function measuring method as claimed in claim 1, comprise tested part, measure the measurement mechanism of noise signal, noise signal source and tail pipe, it is characterized in that: described noise signal source and tail pipe are separately positioned on the two ends of tested part, the measurement mechanism of described measurement noise signal comprises first microphone of the outlet that is arranged on described noise signal source and is arranged on second microphone at tail pipe place, the output signal of described first microphone and second microphone is connected with the noise data disposal system, finish in described noise data disposal system the output signal of described first microphone and the output signal of second microphone are carried out the ratio computing, obtain the frequency response function curve of described tested part.
4. measuring system according to claim 3, it is characterized in that: described noise data disposal system comprises: power amplifier, A/D transducer, be equipped with and finish the computer that two groups of data are carried out the ratio computing and shown the noise software of frequency response function curve, the output signal of the output signal of described first microphone and second microphone is amplified into the A/D transducer through power amplifier respectively and converts digital signal to, and digital signal is input in the computer and handles.
5. measuring system according to claim 3 is characterized in that: described noise signal source comprises white noise, pink noise, sinusoidal signal and four kinds of basic sound sources of 20-2000Hz swept-frequency signal.
6. measuring system according to claim 5 is characterized in that: described noise signal source comprises excitation sound source and power amplifier, and the output of described excitation sound source connects power amplifier, and the output of power amplifier connects the tested part front end.
7. measuring system according to claim 6 is characterized in that: described excitation sound source adopts two cast-in-block metal shells, and the sounding end is a horn designs, inner filling porous material parcel pronunciation loudspeaker.
8. according to arbitrary described measuring system in the claim 3 to 7, it is characterized in that: described tested part, the junction of measuring measurement mechanism, noise signal source and the tail pipe of noise signal all use the porous sound insulating material to seal.
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| CN201110022750.5A CN102175299B (en) | 2011-01-20 | The measuring method of a kind of noise frequency response function and the system of measurement |
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| CN201110022750.5A CN102175299B (en) | 2011-01-20 | The measuring method of a kind of noise frequency response function and the system of measurement |
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| CN102175299A true CN102175299A (en) | 2011-09-07 |
| CN102175299B CN102175299B (en) | 2016-12-14 |
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Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN102928230A (en) * | 2012-10-31 | 2013-02-13 | 芜湖市顺昌汽车配件有限公司 | Bench test device of automobile engine air intake system |
| CN103674227A (en) * | 2012-09-17 | 2014-03-26 | 重庆长安汽车股份有限公司 | Method for testing engine vibration noise under whole-automobile condition |
| CN105467013A (en) * | 2016-01-20 | 2016-04-06 | 华晨汽车集团控股有限公司 | Sound insulating material transmission loss predicting system and method based on mass law |
| CN107179451A (en) * | 2017-05-15 | 2017-09-19 | 深圳市量为科技有限公司 | Integrated low frequency noise measurement device |
| EP3480436A1 (en) * | 2017-11-06 | 2019-05-08 | Eberspächer Exhaust Technology GmbH & Co. KG | Method and device for analysing the acoustics of an exhaust gas flap |
| DE102017129234A1 (en) * | 2017-11-06 | 2019-05-09 | Eberspächer Exhaust Technology GmbH & Co. KG | Method and device for analyzing the acoustic behavior of an exhaust flap |
| CN113916348A (en) * | 2021-09-09 | 2022-01-11 | 山东大学 | Device and method for measuring material transmission loss |
| CN116299147A (en) * | 2023-03-13 | 2023-06-23 | 中国科学院声学研究所 | One-dimensional structure internal sound source positioning method based on acoustic coherence technology |
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Cited By (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103674227A (en) * | 2012-09-17 | 2014-03-26 | 重庆长安汽车股份有限公司 | Method for testing engine vibration noise under whole-automobile condition |
| CN103674227B (en) * | 2012-09-17 | 2015-09-09 | 重庆长安汽车股份有限公司 | Engine vibration and noise test method under whole vehicle state |
| CN102928230A (en) * | 2012-10-31 | 2013-02-13 | 芜湖市顺昌汽车配件有限公司 | Bench test device of automobile engine air intake system |
| CN105467013A (en) * | 2016-01-20 | 2016-04-06 | 华晨汽车集团控股有限公司 | Sound insulating material transmission loss predicting system and method based on mass law |
| CN107179451A (en) * | 2017-05-15 | 2017-09-19 | 深圳市量为科技有限公司 | Integrated low frequency noise measurement device |
| DE102017129234A1 (en) * | 2017-11-06 | 2019-05-09 | Eberspächer Exhaust Technology GmbH & Co. KG | Method and device for analyzing the acoustic behavior of an exhaust flap |
| EP3480436A1 (en) * | 2017-11-06 | 2019-05-08 | Eberspächer Exhaust Technology GmbH & Co. KG | Method and device for analysing the acoustics of an exhaust gas flap |
| CN109752074A (en) * | 2017-11-06 | 2019-05-14 | 埃贝斯佩歇排气技术有限责任两合公司 | Method and apparatus for analyzing the acoustic characteristic of exhaust valve |
| US10753910B2 (en) | 2017-11-06 | 2020-08-25 | Eberspächer Exhaust Technology GmbH & Co. KG | Process and device for the analysis of the acoustic characteristic of an exhaust gas flap |
| CN109752074B (en) * | 2017-11-06 | 2021-04-30 | 埃贝斯佩歇排气技术有限责任两合公司 | Method and device for analyzing acoustic properties of an exhaust valve |
| CN113916348A (en) * | 2021-09-09 | 2022-01-11 | 山东大学 | Device and method for measuring material transmission loss |
| CN113916348B (en) * | 2021-09-09 | 2022-10-18 | 山东大学 | Device and method for measuring material transmission loss |
| CN116299147A (en) * | 2023-03-13 | 2023-06-23 | 中国科学院声学研究所 | One-dimensional structure internal sound source positioning method based on acoustic coherence technology |
| CN116299147B (en) * | 2023-03-13 | 2023-11-28 | 中国科学院声学研究所 | One-dimensional structure internal sound source positioning method based on acoustic coherence technology |
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