1、_ SAE Technical Standards Board Rules provide that: “This report is published by SAE to advance the state of technical and engineering sciences. The use of this report is entirely voluntary, and its applicability and suitability for any particular use, including any patent infringement arising there
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4、0 (outside USA) Fax: 724-776-0790 Email: CustomerServicesae.org SAE WEB ADDRESS: http:/www.sae.org SAE values your input. To provide feedback on this Technical Report, please visit http:/www.sae.org/technical/standards/J2889/1_201511 SURFACE VEHICLE RECOMMENDED PRACTICE J2889-1 NOV2015 Issued 2011-0
5、9 Revised 2015-11 Superseding J2889-1 DEC2014 Measurement of Minimum Noise Emitted by Road Vehicles RATIONALE Updated to correct equations in Table 2 as well as the correct modifier in Appendix As Item #5. FOREWORD This SAE Standard is derived from SAE J2805 which itself is derived from ISO 362-1. T
6、his SAE Standard retains relevant descriptions and requirements for measurement facilities, equipment, ambient conditions and other factors from SAE J2805. TABLE OF CONTENTS 1. SCOPE 2 2. REFERENCES 3 2.1 Applicable Documents 3 3. DEFINITIONS . 4 4. SYMBOLS AND ABBREVIATED TERMS 5 5. INSTRUMENTATION
7、 6 5.1 Instruments for Acoustic Measurement 6 5.2 Instrumentation for Speed Measurements 7 5.3 Meteorological Instrumentation . 7 6. ACOUSTIC ENVIRONMENT, METEOROLOGICAL CONDITIONS, AND BACKGROUND NOISE . 7 6.1 Test Site 7 6.2 Meteorological Conditions . 9 6.3 Background Noise . 10 7. TEST PROCEDURE
8、S . 12 7.1 Full Vehicle Testing . 12 7.2 Measurement of Sound to Determine Frequency Shift . 18 8. TEST REPORT . 22 9. NOTES 22 9.1 Marginal Indicia . 22 SAE J2889-1 NOV2015 Page 2 of 28 APPENDIX A INFORMATION ON DEVELOPMENT OF SAE J2889-1 23 APPENDIX B DEVELOPMENT OF FREQUENCY SHIFT INFORMATION . 2
9、5 APPENDIX C RELEVANCE OF OBJECTIVE ACOUSTIC MEASUREMENTS TO PEDESTRIAN SAFETY . 27 FIGURE 1 TEST SITE DIMENSIONS - SHADED AREA IS THE MINIMUM AREA TO BE COVERED WITH A SURFACE COMPLYING WITH ISO 10844 8 FIGURE 2 DETERMINATION OF THE RANGE OF BACKGROUND NOISE. 10 FIGURE 3 ILLUSTRATIVE EXAMPLE OF COM
10、MENCING MOTION SOUND . 17 FIGURE B1 EXAMPLE OF MEASUREMENT OF FREQUENCY VS. SPEED INFORMATION. . 26 TABLE 1 LISTS SYMBOLS AND THE PARAGRAPH THEY ARE FIRST USED. 5 TABLE 2 CORRECTION FOR BACKGROUND NOISE WHEN MEASURING FULL VEHICLE OVERALL SOUND PRESSURE LEVEL. . 11 TABLE 3 VEHICLE SPEEDS FOR MEASURE
11、MENT . 21 1. SCOPE This SAE Standard is derived from SAE J2805 and specifies an engineering method for measuring the sound emitted by M and N category road vehicles at standstill and low speed operating conditions The specifications reproduce the level of sound which is generated by the principal ve
12、hicle sound sources consistent with stationary and low speed vehicle operating conditions relevant for pedestrian safety. The method is designed to meet the requirements of simplicity as far as they are consistent with reproducibility of results under the operating conditions of the vehicle. The tes
13、t method requires an acoustic environment which is only obtained in an extensive open space or in special designed indoor facilities replicating the conditions of an extensive open space. Such conditions usually exist during: Measurements of vehicles for regulatory certification. Measurements at the
14、 manufacturing stage. Measurements at official testing stations. The results obtained by this method give an objective measure of the sound emitted under the specified conditions of test. It is necessary to consider the fact that the subjective appraisal of the annoyance, perceptibility, and/or dete
15、ctability of different motor vehicles or classes of motor vehicles due to their sound emission are not simply related to the indications of a sound measurement system. As annoyance, perceptibility, and/or detectability are strongly related to personal human perception, physiological human condition,
16、 culture, and environmental conditions, there are large variations and therefore these terms are not useful as parameters to describe a specific vehicle condition. SAE J2889-1 NOV2015 Page 3 of 28 Spot checks of vehicles chosen at random rarely occur in an ideal acoustic environment. If measurements
17、 are carried out on the road in an acoustic environment which does not fulfill the requirements stated in this SAE Standard, the results obtained may deviate appreciably from the results obtained using the specified conditions. In addition, this standard provides an engineering method to assess the
18、performance of external sound generation systems intended for the purpose of providing acoustic information to pedestrians on a vehicles operating condition. This information is reported as objective criteria related to the external sound generation systems sound pressure level, frequency content, a
19、nd changes in sound pressure level and frequency content as a function of vehicle speed. As such, these measures can provide pedestrians with information on the location, speed, direction of travel, acceleration, and deceleration behavior of a vehicle. Annex A contains background information relevan
20、t in the development of this SAE Standard. 2. REFERENCES 2.1 Applicable Documents 2.1.1 SAE Publications Available from SAE International, 400 Commonwealth Drive, Warrendale, PA 15096-0001, Tel: 877-606-7323 (inside USA and Canada) or +1 724-776-4970 (outside USA), www.sae.org. SAE J1715 Hybrid Elec
21、tric Vehicle (HEV) fuel (tank filled to at least 90 % of the capacity specified by the manufacturer); other equipment if included as basic parts for the vehicle, such as spare wheel(s), wheel chocks, fire extinguisher(s), spare parts and tool kit NOTE:The definition of curb (kerb) mass can vary from
22、 country to country, but in this SAE Standard, it refers to the definition contained in ISO 1176. 3.6 MASS IN RUNNING ORDER Nominal mass of an N2, N3 or M2 vehicle having a maximum authorized mass greater than 3 500 kg, or an M3 vehicle as determined by the following conditions: a. the mass is taken
23、 as the sum of the unladen vehicle mass and the drivers mass; b. in the case of category M2 and M3 vehicles that include seating positions for additional crewmembers, their mass is incorporated in the same way and equal to that of the driver NOTE 1 TO ENTRY: The drivers mass is calculated in accorda
24、nce with ISO 2416. SAE J2889-1 NOV2015 Page 5 of 28 3.7 FULL VEHICLE OPERATION Operation of a vehicle with all systems and components operating as per the manufacturers specification for normal road use. 3.8 SIMULATED VEHICLE OPERATION Operation of a vehicle with some systems or components disabled
25、to reduce noise interference during testing. Simulated vehicle operation may include external signals applied to the vehicle to simulate actual in-use signals. 3.9 LOWEST FREQUENCY OF INTEREST Frequency below which there is no signal content relevant to the measurement of sound emission for the vehi
26、cle under test. 4. SYMBOLS AND ABBREVIATED TERMS Table 1 - Lists symbols and the paragraph they are first used. Symbol Unit Clause Explanation AA - 7.1.5.1 Line perpendicular to vehicle travel which indicates beginning of zone to record sound pressure level during test BB - 7.1.5.1 Line perpendicula
27、r to vehicle travel which indicates end of zone to record sound pressure level during test CC - 7.1.1 Centreline of vehicle travel faudible Hz 7.1.6.4 Highest audible frequency of external sound generation system fi, speed Hz 7.2.7.1 Single frequency component of external sound generation system at
28、a given vehicle speed fi, ref Hz 7.2.7.1 Single frequency component of external sound generation system at reference vehicle speed del_f % 7.2.4.3 Frequency shift expressed in percent of a reference frequency. f Hz 7.2.3 Frequency resolution of narrowband analysis used to measure frequency spectrums
29、 for the purpose of determining frequency shift information. fs Hz 7.1.6.4 Sampling frequency used by digital signal processing system j - 6.3.2 Index for single test run within stopped or slow speed cruise test conditions Lst, fwddB 7.1.8 Vehicle A-weighted sound pressure level in stationary forwar
30、d condition. Lsta, rev dB 7.1.8 Vehicle A-weighted sound pressure level in stationary reverse condition. Lstop dB 7.1.8 Vehicle A-weighted sound pressure level L crs dB 7.1.10 Cruise vehicle A-weighted sound pressure level L crs, 10 dB 7.1.10 Cruise vehicle A-weighted sound pressure level at a vehic
31、le speed of 10 km/h. L crs, 20 dB 7.1.10 Cruise vehicle A-weighted sound pressure level at a vehicle speed of 20 km/h. L crs, 30 dB 7.1.10 Cruise vehicle A-weighted sound pressure level at a vehicle speed of 30 km/h. Lcorr dB 6.3.2 Background noise correction Ltest,jdB6.3.2 A-weighted sound pressure
32、 level result of jth test run SAE J2889-1 NOV2015 Page 6 of 28 Symbol Unit Clause Explanation Ltestcorr,jdB6.3.2 A-weighted sound pressure level result of jth test run corrected for background noise LbgndB 6.3.1 Background A-weighted sound pressure level. Lbgn,p-p dB6.3.2 Range of maximum to minimum
33、 value of the representative background noise A-weighted sound pressure level over a defined time period. LxdB A-weighted sound pressure level for any stationary or cruise condition for use in assessment of measurement uncertainty. L dB 6.3.2 A-weighted sound pressure level of jth test result minus
34、the A-weighted background noise level (L = Ltest,j - Lbgn) N - 7.2.3 Block size of digital sample used for discrete Fourier transform or autopower spectrum analysis PP - 7.1.5.2 Line perpendicular to vehicle travel which indicates location of microphones v AAkm/h 5.2 Vehicle velocity when vehicle re
35、ference point in forward motion passes line AA. See 3.1.1 for definition of reference point. v BBkm/h 5.2 Vehicle velocity when vehicle reference point or rear of vehicle in forward motion passes line BB. See 3.1.1 for definition of reference point. v PPkm/h 5.2 Vehicle velocity when reference point
36、 in forward motion passes line PP. See 3.1.1 for definition of reference point. v refkm/h 7.2.4.4 Reference vehicle velocity used for calculating frequency shift percentage. vtest km/h 7.1.5.3 Target vehicle test velocity AA - 7.1.5.1 Line perpendicular to vehicle travel which indicates beginning of
37、 zone to record sound pressure level during test 5. INSTRUMENTATION 5.1 Instruments for Acoustic Measurement 5.1.1 General The apparatus used for measuring the sound pressure level shall be a sound level meter or equivalent measurement system meeting the requirements of Class 1 instruments (inclusiv
38、e of the recommended windscreen, if used). These requirements are described in IEC 61672-1. The entire measurement system shall be checked by means of a sound calibrator that fulfills the requirements of Class 1 sound calibrators according to IEC 60942. Measurements shall be carried out using the ti
39、me weighting “F“ of the acoustic measurement instrument and the “A“ frequency weighting also described in IEC 61672-1. When using a system that includes a periodic monitoring of the A-weighted sound pressure level, a reading should be made at a time interval not greater than 30 ms. The instruments s
40、hall be maintained and calibrated in accordance to the instructions of the instrument manufacturer. 5.1.2 Calibration At the beginning and at the end of every measurement session, the entire acoustic measurement system shall be checked by means of a sound calibrator as described in 5.1.1. Without an
41、y further adjustment, the difference between the readings shall be less than or equal to 0.5 dB. If this value is exceeded, the results of the measurements obtained after the previous satisfactory check shall be discarded. SAE J2889-1 NOV2015 Page 7 of 28 5.1.3 Compliance with requirements Complianc
42、e of the sound calibrator with the requirements of IEC 60942 shall be verified once a year. Compliance of the instrumentation system with the requirements of IEC 61672-1 shall be verified at least every 2 years. All compliance testing shall be conducted by a laboratory which is authorized to perform
43、 calibrations traceable to the appropriate standards. 5.2 Instrumentation for Speed Measurements The road speed of the vehicle shall be measured with instruments meeting specification limits of at least 0.5 km/h when using continuous measuring devices. If testing uses independent measurements of spe
44、ed, this instrumentation shall meet specification limits of at least 0.2 km/h. These requirements are only valid for full vehicle testing. NOTE: Independent measurements of speed are when two or more separate devices will determine the v AAv BB and v PPvalues. A continuous measuring device will dete
45、rmine all required speed information with one device 5.3 Meteorological Instrumentation The meteorological instrumentation used to monitor the environmental conditions during the test shall meet the specifications of: 1 C or less for a temperature measuring device; 1.0 m/s for a wind speed-measuring
46、 device; 5 hPa for a barometric pressure measuring device; 5 % for a relative humidity measuring device. 6. ACOUSTIC ENVIRONMENT, METEOROLOGICAL CONDITIONS, AND BACKGROUND NOISE 6.1 Test Site 6.1.1 General The specifications for the test site provide the necessary acoustic environment to carry out t
47、he full vehicle or component level tests documented in this SAE standard. Outdoor and indoor test environments that meet the specifications of this SAE Standard provide equivalent acoustic environments and produce results that are equally valid. 6.1.2 Outdoor testing The test site shall be substanti
48、ally level. The test track construction and surface shall meet the requirements of ISO 10844:2011, ISO 10844:2014, or ISO 10844:1994. Within a radius of 50 m around the center of the track, the space shall be free of large reflecting objects such as fences, rocks, bridges or buildings. The test trac
49、k and the surface of the site shall be dry and free from absorbing materials such as powdery snow, or loose debris. In the vicinity of the microphone, there shall be no obstacle that could influence the acoustic field and no person shall remain between the microphone and the noise source. The meter observer shall be positioned so as not to influence the meter reading. SAE J2889-1 NOV2015 Pag
