SAE J 986-1998 Sound Level for Passenger Cars and Light Trucks.pdf

1、 6$(7HFKQLFDO6WDQGDUGV%RDUG5XOHVSURYLGHWKDW7KLVUHSRUWLVSXEOLVKHGE6$(WRDGYDQFHWKHVWDWHRIWHFKQLFDO 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 tKHUHIURPLVWKHVROHUHVSRQVL

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4、0 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/J986_201311 SURFACE VEHICLE RECOMMENDED PRACTICE J986 NOV2013 Issued 1967-07 Reaffirmed 2013-11 Superseding J986

5、MAY1998 Sound Level for Passenger Cars and Light Trucks RATIONALE J986 has been reaffirmed to comply with the SAE five year review policy. 1. ScopeThis SAE Standard establishes the test procedure, environment, and instrumentation for determiningthe exterior sound level for passenger cars, multipurpo

6、se vehicles, and light trucks having a gross vehiclemass rating of 4540 kg or less. The test procedure is characterized by having fixed initial conditions, i.e., anas-specified initial vehicle speed and gear selection at a fixed start point on the test site. Full-throttleacceleration and closed-thro

7、ttle deceleration of the vehicle are included in this procedure.Sound levels determined in accordance with this document are dependent on the performance capability ofthe test vehicle, as influenced by power-to-mass ratio and overall powertrain gear ratio.2. References2.1 Applicable PublicationsThe

8、following publications form a part of this specification to the extent specifiedherein. The latest issue of SAE publications shall apply.2.1.1 SAE PUBLICATIONSAvailable from SAE, 400 Commonwealth Drive, Warrendale, PA 15096-0001.SAE J184Qualifying a Sound Data Acquisition SystemSAE J1349Engine Power

9、 Test CodeSpark Ignition and Diesel2.1.2 ANSI PUBLICATIONSAvailable from 11 West 42nd Street, New York, NY 10036-8002.ANSI S1.4-1983Specification for Sound Level MetersANSI S14A-1985Sound Level Meters2.1.3 U.S. Environmental Protection Agency Noise Advisory Circular: A/C No. 3, January 27, 19783. De

10、finitions3.1 Curb MassThe mass of the vehicle with standard equipment, optional equipment, and fluids filled tocapacity.3.2 Multi-fuel VehicleA vehicle, such as a dual- or bi-fuel vehicle, equipped to operate on more than one typeof fuel, e.g., either compressed natural gas or gasoline.3.3 Variable

11、Fuel VehicleA vehicle equipped to operate on a variety of fuel blends, e.g., a mixture of gasolineand methanol.3.4 Rated Engine SpeedThe engine speed at which the engine delivers rated power output as defined inSAE J1349, as determined by the manufacturer.3.5 Throttle ControlThe driver operated peda

12、l (or other control) which connects through some mechanism tothe engine fuel metering device (carburetor, fuel injectors, fuel distributor, or equivalent device) and therebycontrols the engine power output.NOTEFor the purpose of this document, depression of the throttle control acts to increase engi

13、ne speedand release of the throttle control acts to reduce engine speed.4. Vehicle Operation4.1 The test mass of the vehicle, including the driver and equipment, shall not exceed 125 kg over the curb mass(fuel level may be reduced as needed to ensure that this requirement is met).4.2 The powertrain

14、and exhaust system temperatures shall be within the normal operating range throughout eachtest run. A 1 min stabilizing period with the engine at idle speed and the transmission in neutral is requiredprior to each test run.NOTEUsually a vehicle brought to normal engine coolant temperature through mo

15、derate driving operationsis adequately conditioned for testing.4.3 Vehicle tires shall be inflated to the proper pressure in accordance with the manufacturers recommendations.4.4 Preliminary runs to familiarize the driver and to establish the vehicle operating conditions should be madebefore taking

16、sound level measurements.4.5 Acceleration TestThe acceleration test is the primary test mode and must be conducted first to obtaininformation necessary to conduct the deceleration test.4.5.1 For this test, the vehicle shall approach the measurement area along the vehicle path with the vehicle speeds

17、tabilized at 48 km/h 1.2 km/h. The highest-numerical-ratio transmission gear shall be used that will resultin the front of the vehicle reaching or passing the entry point of the end zone before rated engine speed isattained. It is recommended that the approach speed be held constant for a distance o

18、f at least 7.5 m priorto reaching the start point.When the front of the vehicle reaches the start point 1.5 m, the throttle control shall be fully depressed asrapidly as possible and the vehicle allowed to accelerate until the engine reaches rated engine speed. Thetest run is then terminated and the

19、 throttle control may be released.Should rated engine speed not be attained in the end zone, the test run is nonetheless terminated when thefront of the vehicle reaches the end of the end zone. The maximum engine speed attained should be noted.(See 4.5.1)._SAE INTERNATIONAL J986 Reaffirmed NOV2013 P

20、age 2 of 74.5.2 When vehicles equipped with automatic transmissions downshift from the gear ratio determined inaccordance with 4.5.1, the downshift shall be prevented by one of the following methods:a. The approach speed of the vehicle may be increased to a maximum of 60 km/h.b. Maintain the speed a

21、t 48 km/h, with the fuel supply to the engine limited to 95% of the supplynecessary for full load.NOTEThis condition shall be satisfied in the case of a spark-ignition engine when the angle of the butterflyvalve is 90% of full travel, and in the case of a compression-ignition engine when the movemen

22、t ofthe feed-rack of the injection pump is limited to 90% of its stroke.c. The downshift mechanism may be disabled as recommended by the vehicle manufacturer.d. Establish an electronic program that will maintain the gear selected and prevent changes to any othergear ratio.4.5.3 If the vehicle is equ

23、ipped with all-wheel drive that can be engaged or disengaged by operator control, theposition used for normal urban driving shall be used.4.5.4 If the vehicle is equipped with a multi-mode exhaust system that can be switched between modes byoperator control, the vehicle shall be tested in each mode

24、and the mode yielding the highest sound levelshall be recorded.4.5.5 If the vehicle is equipped with two or more driving modes (e.g., “normal“ and “performance“) affectingtransmission shift schedules that can be engaged by operator control, the vehicle shall be tested in eachmode and the mode yieldi

25、ng the highest sound level shall be recorded.4.5.6 If the vehicle is equipped for operation on variable fuels or fuel mixtures, or if the vehicle is equipped formultiple (dual- or bi-) fuel operation, the vehicle shall be tested using each fuel or fuel mixture unless priortesting has established tha

26、t the maximum sound level is produced when using a particular fuel or fuelmixture, in which case the vehicle shall be tested using that fuel or fuel mixture only.4.5.7 If the vehicle is equipped with two or more multi-mode systems yielding a large number of possiblecombinations then a sufficient num

27、ber of combinations shall be tested to establish a sound level range.Henceforth, a combination deemed to produce the highest sound levels in the sound level range shall betested, and these data shall be recorded.4.6 Deceleration TestThe deceleration test shall also be conducted unless prior testing

28、has established that themaximum sound level is produced in the acceleration test mode.4.6.1 The maximum engine speed attained in the acceleration test is to be used as the approach speed for thedeceleration test (if conducted). This approach speed will be rated engine speed or the average of theterm

29、inal engine speed values at the end of the end zone as determined in 5.4.1.4.6.2 For this test, the vehicle shall approach the measurement area along the vehicle path in the same gear usedfor the acceleration test with the engine speed stabilized at the speed determined according to 4.5.1. It isreco

30、mmended that the approach speed be held constant for a distance of at least 7.5 m prior to reaching thestart point. When the front of the vehicle reaches the start point 1.5 m, the throttle control shall becompletely released as rapidly as possible and the vehicle allowed to decelerate until the eng

31、ine speeddrops to one-half the approach speed or the front of the vehicle reaches the end of the end zone._SAE INTERNATIONAL J986 Reaffirmed NOV2013 Page 3 of 75. Measurements5.1 The sound level meter shall be set for fast (F) exponential time-averaging and for the A-weighted network.5.2 The ambient

32、 sound level at the test site due to sources other than the vehicle being measured, including windeffects, shall be at least 10 dB lower than the sound level produced by the vehicle under test. To improve therepeatability of the measurement, a 15 dB signal to ambient level is preferred.5.3 Measureme

33、nts shall be made only when the wind speed does not exceed 19 km/h.5.4 The sound level meter or indicating instrument shall be observed during the constant-speed approach andacceleration or deceleration test phases specified in 4.4 or 4.5. The highest sound level occurring during thisobservation per

34、iod shall be recorded. If a sound peak is obviously out of character with the general soundlevels observed, the measurement shall be discarded.5.4.1 If an instantaneous sound level “spike“ occurs at depression of the throttle control at the start of theacceleration test due to momentary loss of tire

35、 traction (tire “chirp“), the “spike“ shall be disregarded.5.5 Measurements are to be made on each side of the vehicle, four consecutive valid measurements within 2 dBare achieved. The arithmetic average of these four measurements is the reported level for that side of thevehicle. The figure reporte

36、d for the vehicle is the highest side average.5.6 The reported sound level shall be that for the side of the vehicle having the highest sound level, as determinedaccording to 5.5, from either the acceleration test mode or the deceleration test mode (if conducted).6. Instrumentation6.1 The instrument

37、ation necessary to conduct this test shall meet the minimum performance requirementsspecified as follows.6.2 The sound level meter shall meet the Type 1 or S1A requirements of ANSI S1.4-1983 and S1.4A-1985.6.2.1 As an alternative to making direct measurements using a sound level meter, a microphone

38、or sound levelmeter may be used with a magnetic tape recorder and/or a graphic level recorder or other indicatinginstrument providing the system is in conformance with SAE J184.6.3 The sound level calibrator shall be accurate to 0.5 dB (see 8.3.4).6.4 Engine and vehicle speed shall be measured with

39、instruments having an accuracy of 2% at the speedsrequired for the measurements being made (see 8.4).6.5 The anemometer shall be accurate to 10% at 19 km/h wind speed.6.6 A microphone windscreen may be used, provided that it does not affect the microphone response more than1 dB for frequencies from

40、20 to 4000 Hz and 1.5 dB for frequencies from 4000 to 10 000 Hz._SAE INTERNATIONAL J986 Reaffirmed NOV2013 Page 4 of 77. Test Site7.1 The test site shall be a flat, open space free of large reflecting surfaces such as parked vehicles, signboards,buildings, or hillsides located within 30 m of the mea

41、surement area. The measurement area, which is definedas the plane surface fixed by the point at the microphone location and the end points of the end zone on the farside of the traffic lane in both directions of vehicle travel, shall be flat to within 0.05 m. The entire plane mayslope toward or away

42、 from the microphone for drainage. The vehicle path shall be of minimal grade end-to-end to avoid variations in vehicle loading. To minimize measurement variability, it is recommended that a two-sided site have both measurement areas in the same uniform plane. See 7.5 and 7.6, Figure 1, and Appendix

43、A for flatness measurement procedure.7.2 The surface of the measurement area shall be concrete or nonporous asphalt, dry, and free from snow, soil, orother extraneous material.7.3 The test site shall include a vehicle path of relatively smooth concrete or asphalt, dry, and free of extraneousmaterial

44、s such as gravel and of sufficient length for acceleration, deceleration, and stopping of the vehicle.7.4 The test site surface sound absorption coefficient (normal incidence), as measured in situ by the impedancetube method, shall be 0.10 or less.7.5 The microphone shall be located 15 m from the ce

45、nterline of the vehicle path and 1.2 m above the groundplane. The reference axis of the microphone shall lie in the vertical plane containing the perpendicular to thevehicle path through the microphone location.7.6 The following fixed points and zones shall be established on the vehicle path:7.6.1 T

46、he start point, 7.5 m ahead of the perpendicular to the vehicle path through the microphone location.7.6.2 The end zone, starting at 7.5 m beyond, and ending at 38 m beyond the perpendicular to the vehicle paththrough the microphone location.7.7 If it is desired to measure the sound level for both s

47、ides of the vehicle during each test run, anothermicrophone location, measurement area, and clear area shall be established laterally opposite, meeting therequirements of 7.1, 7.2, and 7.5.8. General Comments8.1 It is recommended that persons technically trained and experienced in current sound measurementtechniques, select the test instrumentation and conduct the tests.8.2 When making sound level measurements, not more than one person other than the observer reading themeter shall be within 15 m of the vehicle or micropho