CN108318130B - Noise source identification method for accelerating out-of-vehicle noise test - Google Patents
Noise source identification method for accelerating out-of-vehicle noise test Download PDFInfo
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- CN108318130B CN108318130B CN201810304805.3A CN201810304805A CN108318130B CN 108318130 B CN108318130 B CN 108318130B CN 201810304805 A CN201810304805 A CN 201810304805A CN 108318130 B CN108318130 B CN 108318130B
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- 238000000034 method Methods 0.000 title claims abstract description 27
- 238000012360 testing method Methods 0.000 title claims abstract description 16
- 238000001816 cooling Methods 0.000 claims abstract description 32
- 230000001133 acceleration Effects 0.000 claims abstract description 6
- 238000005452 bending Methods 0.000 claims description 9
- 230000008030 elimination Effects 0.000 claims description 4
- 238000003379 elimination reaction Methods 0.000 claims description 4
- 238000001228 spectrum Methods 0.000 abstract description 4
- 238000005259 measurement Methods 0.000 abstract description 3
- 238000004519 manufacturing process Methods 0.000 description 2
- 230000003584 silencer Effects 0.000 description 2
- 230000007547 defect Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
Classifications
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01H—MEASUREMENT OF MECHANICAL VIBRATIONS OR ULTRASONIC, SONIC OR INFRASONIC WAVES
- G01H17/00—Measuring mechanical vibrations or ultrasonic, sonic or infrasonic waves, not provided for in the preceding groups
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M17/00—Testing of vehicles
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T90/00—Enabling technologies or technologies with a potential or indirect contribution to GHG emissions mitigation
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- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Exhaust Silencers (AREA)
- Measurement Of Mechanical Vibrations Or Ultrasonic Waves (AREA)
Abstract
The invention discloses a noise source identification method for an acceleration driving vehicle external noise test, which comprises the following specific steps: step 1: classifying the noise sources outside the vehicle accelerating the running, and step 2: the normally running vehicle is accelerated to run through a noise measuring area, then a noise comparison value is measured, and step 3: judging and identifying cooling fan noise, and step 4: judging and identifying noise of the exhaust muffler, and step 5: the method of cancellation is used to determine if the noise source is engine block noise. The invention also discloses a structure of the exhaust port turning device. The invention can not only conveniently and accurately confirm the noise source and solve the problem that the noise frequency of the engine body is similar to that of the exhaust muffler in the prior art and cannot be judged through the frequency spectrum characteristics, but also does not increase or change the measurement scene, and is convenient, practical and accurate.
Description
Technical Field
The invention relates to the field of automobile manufacturing and production, in particular to a noise source identification method for an outside noise test of an accelerated driving automobile.
Background
Noise pollution is an environmental problem, so that special regulations (for example, GB1495-2002, ISO 362-1-2007, ECE R51-03 and the like) in various countries are used for limiting noise outside an accelerating vehicle, the noise is increasingly strict (the requirement of the regulations is reduced by 2-3 dB at intervals), and vehicles which cannot meet the requirement cannot be sold on the market.
The main noise sources of noise outside the accelerating vehicle can be generally classified into engine body noise, exhaust muffler noise, cooling fan noise, and the like. Different noise sources adopt different noise treatment schemes, and only the main noise source is judged to be capable of carrying out targeted noise improvement.
In the prior art, cooling fan noise can be considered to be a main noise source by manually canceling fan rotation, but engine body noise and exhaust silencer noise are generally similar in frequency and cannot be judged through frequency spectrum characteristics, and an exhaust port is generally exposed, so that if the exhaust silencer is a main noise source, the problem can be effectively solved by improving the part.
In existing vehicles, the exhaust ports of most vehicles are generally oriented in a rearward or rearward and simultaneously downward direction. In the test, the difference of the influence of the exhaust noise on the left and right sides of the standard measuring place is not large enough, and whether the exhaust noise is a main noise source cannot be distinguished.
Disclosure of Invention
The invention discloses a noise source identification method for an out-of-vehicle noise test of an accelerated traveling vehicle, which mainly aims to overcome the defects and shortcomings in the prior art.
The technical scheme adopted by the invention is as follows:
a noise source identification method for an acceleration driving vehicle external noise test comprises the following specific steps:
step 1: classifying the noise sources outside the vehicle for accelerating the running into three main categories, namely engine body noise, exhaust muffler noise and cooling fan noise;
step 2: accelerating a normally running vehicle to pass through a noise measuring area, and then measuring to obtain a noise comparison value;
step 2: judging and identifying the noise of the cooling fan, accelerating the vehicle to pass through a noise measuring area by canceling or starting the cooling fan, calculating according to the measuring result and the noise comparison value obtained in the step 2 to obtain a noise pressure level, and judging whether the noise is a noise source according to the noise pressure level;
step 3: when the noise source is not the noise of the cooling fan, judging and identifying the noise of the exhaust muffler, firstly measuring to obtain a noise value of the exhaust muffler, then calculating according to the noise value obtained by the measuring result and the noise comparison value obtained by the step 2 to obtain a noise sound pressure level, and judging whether the noise is the noise source according to the noise sound pressure level;
step 4: when the noise source is not exhaust muffling noise, the engine body noise is determined as the noise source by using a removal method.
Further, the judging of the noise of the cooling fan in the step 3 includes the following specific steps:
(1) Closing a cooling fan, accelerating the vehicle to pass through a noise measuring area, and recording noise data 1 obtained by measuring microphones placed on the left side and the right side of the noise measuring area;
(3) Then according to the formula for calculating sound pressure level:wherein: p is noise data 1, P0 is noise comparison value, and sound pressure level is obtained;
(4) When the obtained sound pressure level is 3dB or more, the noise source is the cooling fan noise.
Further, the step 4 of judging and identifying the noise of the exhaust muffler includes the following specific methods:
(1) An exhaust port direction changing device capable of adjusting the direction of an exhaust port is arranged on the exhaust port of the exhaust muffler;
(2) Firstly, adjusting the direction of the exhaust port steering device to one of the left and right directions, accelerating the vehicle to pass through a noise measuring area, and then recording noise data 2 and noise data 3 obtained by measuring microphones placed at the left and right sides of the noise measuring area;
(3) Comparing the noise data 2 with the noise data 3, and when the variation value of the noise data is more than 3dB, the noise source is exhaust muffler noise.
Further, when the exhaust port of the vehicle in the step (2) is installed on the right side, the direction of the exhaust port direction changing device is left; when the vehicle exhaust port is arranged on the left side, the direction of the exhaust port steering device is right.
Still further, the exhaust port direction changing device in the step (1) includes: the vehicle steering device comprises a first connecting pipe body, a steering connecting pipe body, a second straight connecting pipe body and a third bending pipe body, wherein the first connecting pipe body comprises a fixed connecting end and a movable connecting end, the fixed connecting end is detachably and fixedly arranged at a vehicle exhaust port through a clamp, the fixed connecting end is matched and sleeved in the exhaust port, and the movable connecting end of the first connecting pipe body is rotatably and obliquely arranged in a downward extending mode; the steering connecting pipe body is respectively connected with the movable connecting end of the first connecting pipe body and the second straight connecting pipe body, one end of the second straight connecting pipe body is connected with the steering connecting pipe body through a connecting flange, and the other end of the second straight connecting pipe body is connected with the third bending pipe body through a connecting elbow pipe.
Still further, the first connection pipe body has an outer diameter smaller than an inner diameter of the vehicle exhaust port.
Further, the angle of downward inclination of the movable connecting end of the first connecting pipe body is 30-45 degrees.
Furthermore, the second direct connection pipe body is fixedly connected with the vehicle through a fixed clamping ring.
Further, the third bending tube body is oriented in any one of left and right directions.
As can be seen from the above description of the present invention, the present invention has the following advantages compared with the prior art:
firstly judging cooling fan noise, investigating the influence of the cooling fan noise by artificially canceling the rotation of the fan, and judging and identifying whether the cooling fan noise is a noise source in a datamation manner through a set sound pressure level formula; when the cooling fan is determined to be not the most dominant noise source, judging the noise of the exhaust muffler, installing an exhaust port steering device capable of adjusting and changing the direction of an exhaust hole, obtaining different noise data through measuring microphones at the left side and the right side of a noise measuring area, comparing the data, and judging whether the noise source is the noise of the exhaust muffler; when it is determined that the exhaust muffler is not the dominant noise source, the method of elimination may be used to directly identify the noise source as engine block noise. The noise source identification method not only can very conveniently and accurately confirm the noise source and solve the problem that the noise frequency of the engine body is similar to that of the exhaust muffler in the prior art and cannot be judged through the frequency spectrum characteristics, but also does not increase or change the measurement scene, and is convenient, practical and accurate.
Drawings
Fig. 1 is a schematic view of a simple structure of the exhaust port redirecting device of the present invention.
Detailed Description
Specific embodiments of the present invention will be further described with reference to the accompanying drawings.
As shown in fig. 1, a noise source identification method for an acceleration driving vehicle external noise test includes the following specific steps:
step 1: classifying the noise sources outside the vehicle for accelerating the running into three main categories, namely engine body noise, exhaust muffler noise and cooling fan noise;
step 2: accelerating a normally running vehicle to pass through a noise measuring area, and then measuring to obtain a noise comparison value;
step 2: judging and identifying the noise of the cooling fan, accelerating the vehicle to pass through a noise measuring area by canceling or starting the cooling fan, calculating according to the measuring result and the noise comparison value obtained in the step 2 to obtain a noise pressure level, and judging whether the noise is a noise source according to the noise pressure level;
step 3: when the noise source is not the noise of the cooling fan, judging and identifying the noise of the exhaust muffler, firstly measuring to obtain a noise value of the exhaust muffler, then calculating according to the noise value obtained by the measuring result and the noise comparison value obtained by the step 2 to obtain a noise sound pressure level, and judging whether the noise is the noise source according to the noise sound pressure level;
step 4: when the noise source is not exhaust muffling noise, the engine body noise is determined as the noise source by using a removal method.
Further, the judging of the noise of the cooling fan in the step 3 includes the following specific steps:
(1) Closing a cooling fan, accelerating the vehicle to pass through a noise measuring area, and recording noise data 1 obtained by measuring microphones placed on the left side and the right side of the noise measuring area;
(3) Then according to the formula for calculating sound pressure level:wherein: p is noise data 1, P0 is noise comparison value, and sound pressure level is obtained;
(4) When the obtained sound pressure level is 3dB or more, the noise source is the cooling fan noise.
Further, the step 4 of judging and identifying the noise of the exhaust muffler includes the following specific methods:
(1) An exhaust port direction changing device capable of adjusting the direction of an exhaust port is arranged on the exhaust port of the exhaust muffler;
(2) Firstly, adjusting the direction of the exhaust port steering device to one of the left and right directions, accelerating the vehicle to pass through a noise measuring area, and then recording noise data 2 and noise data 3 obtained by measuring microphones placed at the left and right sides of the noise measuring area;
(3) Comparing the noise data 2 with the noise data 3, and when the variation value of the noise data is more than 3dB, the noise source is exhaust muffler noise.
Further, when the exhaust port of the vehicle in the step (2) is installed on the right side, the direction of the exhaust port direction changing device is left; when the vehicle exhaust port is arranged on the left side, the direction of the exhaust port steering device is right.
As shown in fig. 1, the exhaust port turning device in the step (1) includes: the vehicle steering device comprises a first connecting pipe body 1, a steering connecting pipe body 2, a second straight connecting pipe body 3 and a third bending pipe body 4, wherein the first connecting pipe body 1 comprises a fixed connecting end 11 and a movable connecting end 12, the fixed connecting end 11 is detachably and fixedly arranged at a vehicle exhaust port through a clamp 5, the fixed connecting end 12 is matched and sleeved in the exhaust port, and the movable connecting end 12 of the first connecting pipe body 1 can be rotatably and obliquely and downwardly extended; the turning connecting pipe body 2 is respectively connected with the movable connecting end 12 of the first connecting pipe body 1 and the second straight connecting pipe body 3, one end of the second straight connecting pipe body 3 is connected with the turning connecting pipe body 2 through a connecting flange 6, and the other end is connected with the third bending pipe body 4 through a connecting elbow pipe.
Still further, the outer diameter of the first connection pipe body 1 is smaller than the inner diameter of the vehicle exhaust port.
Further, the movable connection end 12 of the first connection pipe body 1 is inclined downward by an angle of 30 ° -45 °.
Furthermore, the second direct connection pipe body 3 is fixedly connected with the vehicle through a fixed clamping ring.
Further, the third bending tube body 4 is oriented in either one of left and right directions.
As can be seen from the above description of the present invention, the present invention has the following advantages compared with the prior art:
firstly judging cooling fan noise, investigating the influence of the cooling fan noise by artificially canceling the rotation of the fan, and judging and identifying whether the cooling fan noise is a noise source in a datamation manner through a set sound pressure level formula; when the cooling fan is determined to be not the most dominant noise source, judging the noise of the exhaust muffler, installing an exhaust port steering device capable of adjusting and changing the direction of an exhaust hole, obtaining different noise data through measuring microphones at the left side and the right side of a noise measuring area, comparing the data, and judging whether the noise source is the noise of the exhaust muffler; when it is determined that the exhaust muffler is not the dominant noise source, the method of elimination may be used to directly identify the noise source as engine block noise. The noise source identification method not only can very conveniently and accurately confirm the noise source and solve the problem that the noise frequency of the engine body is similar to that of the exhaust muffler in the prior art and cannot be judged through the frequency spectrum characteristics, but also does not increase or change the measurement scene, and is convenient, practical and accurate.
The foregoing is merely illustrative of specific embodiments of the present invention, and the design concept of the present invention is not limited thereto, and any insubstantial modifications made by the present invention shall fall within the scope of protection of the present invention.
Claims (8)
1. A noise source identification method for an outside noise test of an accelerating vehicle is characterized by comprising the following steps of: the noise source identification method comprises the following specific steps:
step 1: classifying the noise sources outside the vehicle for accelerating the running into three main categories, namely engine body noise, exhaust muffler noise and cooling fan noise;
step 2: accelerating a normally running vehicle to pass through a noise measuring area, and then measuring to obtain a noise comparison value;
step 3: judging and identifying the noise of the cooling fan, accelerating the vehicle to pass through a noise measuring area by canceling or starting the cooling fan, calculating according to the measuring result and the noise comparison value obtained in the step 2 to obtain a noise pressure level, and judging whether the noise is a noise source according to the noise pressure level;
step 4: when the noise source is not the noise of the cooling fan, judging and identifying the noise of the exhaust muffler, firstly measuring to obtain a noise value of the exhaust muffler, then calculating according to the noise value obtained by the measuring result and the noise comparison value obtained by the step 2 to obtain a noise sound pressure level, and judging whether the noise is the noise source according to the noise sound pressure level;
step 5: when the noise source is not exhaust noise elimination noise, determining the noise source as engine body noise by using an elimination method;
the step 4 of judging and identifying the noise of the exhaust muffler comprises the following specific methods:
(1) An exhaust port direction changing device capable of adjusting the direction of an exhaust port is arranged on the exhaust port of the exhaust muffler;
(2) Firstly, adjusting the direction of the exhaust port steering device to one of the left and right directions, accelerating the vehicle to pass through a noise measuring area, and then recording noise data 2 and noise data 3 obtained by measuring microphones placed at the left and right sides of the noise measuring area;
(3) Comparing the noise data 2 with the noise data 3, and when the variation value of the noise data is more than 3dB, the noise source is exhaust muffler noise.
2. The noise source identification method for an outside-vehicle noise test for acceleration according to claim 1, wherein: the step 3 of judging the noise of the cooling fan comprises the following specific steps:
(1) Closing a cooling fan, accelerating the vehicle to pass through a noise measuring area, and recording noise data 1 obtained by measuring microphones placed on the left side and the right side of the noise measuring area;
(2) Then according to the formula for calculating sound pressure level:wherein: p is noise data 1, P0 is noise comparison value, and sound pressure level is obtained;
(3) When the obtained sound pressure level is 3dB or more, the noise source is the cooling fan noise.
3. The noise source identification method for an outside-vehicle noise test for acceleration according to claim 1, wherein: when the vehicle exhaust port in the step (2) is arranged on the right side, the direction of the exhaust port steering device is left; when the vehicle exhaust port is arranged on the left side, the direction of the exhaust port steering device is right.
4. The noise source identification method for an outside-vehicle noise test for acceleration according to claim 1, wherein: the exhaust port turning device in the step (1) comprises: the vehicle steering device comprises a first connecting pipe body, a steering connecting pipe body, a second straight connecting pipe body and a third bending pipe body, wherein the first connecting pipe body comprises a fixed connecting end and a movable connecting end, the fixed connecting end is detachably and fixedly arranged at a vehicle exhaust port through a clamp, the fixed connecting end is matched and sleeved in the exhaust port, and the movable connecting end of the first connecting pipe body is rotatably and obliquely arranged in a downward extending mode; the steering connecting pipe body is respectively connected with the movable connecting end of the first connecting pipe body and the second straight connecting pipe body, one end of the second straight connecting pipe body is connected with the steering connecting pipe body through a connecting flange, and the other end of the second straight connecting pipe body is connected with the third bending pipe body through a connecting elbow pipe.
5. The noise source recognition method for an accelerated traveling vehicle external noise test of claim 4, wherein: the outer diameter of the first connecting pipe body is smaller than the inner diameter of the vehicle exhaust port.
6. The noise source recognition method for an accelerated traveling vehicle external noise test of claim 4, wherein: the angle of downward inclination of the movable connecting end of the first connecting pipe body is 30-45 degrees.
7. The noise source recognition method for an accelerated traveling vehicle external noise test of claim 4, wherein: the second direct connection pipe body is fixedly connected with the vehicle through a fixed clamping ring.
8. The noise source recognition method for an accelerated traveling vehicle external noise test of claim 4, wherein: the third bending tube body is oriented in any one of left and right directions.
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| CN109443793B (en) * | 2018-10-12 | 2021-04-09 | 东风汽车有限公司 | Method for testing noise outside automobile |
| CN109781245B (en) * | 2019-01-15 | 2021-03-23 | 江铃汽车股份有限公司 | Objective evaluation method for pulse noise of diesel engine |
| CN113532635B (en) * | 2021-08-18 | 2024-02-09 | 广东电网有限责任公司 | Noise silence evaluation method and device for power transmission and transformation project |
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