GB 24929-2010Limit and measurement method of noise emitted by accelerating all-terrain vehicles (English PDF)

5.1 Acoustic measuring instruments

5.1.1 for measuring the sound level of the sound level meter or equivalent measurement system should be consistent with GB/T 3785 type 1 precision sound level meter requirements.

Note. Whenever possible, use the extension rods and extension cables.

5.1.2 At the beginning and end of each series of measurements, use a suitable sound source (such as a piston sound meter) according to GB/T 15173 requirements Checked and calibrated sound level meter. Use Sound Level Meters "fast (F)" profile Time weighting characteristics and "A" frequency weighting characteristics measurement measurements.

5.1.3 measurement process, should be required to use the sound level meter windshield instructions correctly, it should be noted windshield on the microphone sensitivity And directional influence.

5.2 vehicle speed and engine speed measuring instruments You should use a dedicated vehicle speed and engine tachometer measuring instruments, which should be consistent with the requirements of GB/T 5378 regulations.

5.3 Meteorological measuring instruments Anemometer, air pressure gauge and a thermometer should be consistent with GB/T 5378 regulations.

6 accelerated running noise test method

6.1.1 Measurement site (FIG. 1) Center

6.1.1.1 to survey the site should be a solid flat area surrounding the detection of the acceleration parts, this central acceleration section should be flat; Its surface should be dry, there should be no snow, dirt or similar sound absorbing material covered. Detecting road surface coating should be consistent with GB 16169-2005 Appendix B requirements.

6.1.1.2 on the measuring site, accelerated change free-field sound source and the microphone part of the center should not exceed 1dB (A). If the center portion 50m in the acceleration range, no large sound reflecting objects, such as buildings, fences, rocks, bridges, trees and parked Vehicle, can be considered for this condition is satisfied.

6.1.1.3 should not in any way that could affect the sound field microphone barrier, no one should stand between the microphone and the sound source, the measurement Own work stations observers should not affect the readings measuring device.

6.1.2 Meteorology Measurement should be no rain, no snow and the wind speed of not more than 3m/s climatic conditions. Excluding the impact should be measured gusts of sound level meter readings.

6.1.3 Background noise The measurement process, the A-weighted sound level of sound sources influence the detection of the vehicle other than the wind formed (background noise) ratio should be at least test the whole earth Noise generated by the car-shaped low 10dB (A) above. If the difference between the ambient noise and the measured noise is between 10dB (A) ~ 16dB (A) of the Room noise measured value of the test vehicle shall be reduced by the correction value shown in Figure 2. In meters 1 with noise measurement site, measurement region and microphone arrangement Figure 2 correction value of the background noise

6.2 Vehicle Condition

6.2.1 During the measurement, the test vehicle in addition to a pilot, shall not load and without people, vehicles should be in working order (including cooling Fluid, lubricants, fuel, tools, spare wheel). The total mass of the driver and their equipment should be between 75kg ~ 80kg, if necessary, increase Additional weights of 75kg to meet the minimum requirements.

6.2.2 If the test subject is equipped with automatic fans, in the measurement process, this system should be undisturbed.

6.2.3 before measuring, speed warm-up test shall be subject to the normal operation, and the vehicle engine to reach normal operating temperature.

6.3 Measurement Methods

6.3.1 The nature and number of measurements When traveling vehicle line AA 'and BB' between the measurement of A-weighted decibel [dB (A)] represents the maximum sound level. If the record Between the maximum value and the general sound level difference abnormally recorded, this measurement is invalid. On each side of the vehicle should be at least 2 measurements.

6.3.2 microphone position The microphone should be placed away from the runway reference line CC '(FIG. 1) 7.5m ± 0.2m above the ground and at a position 1.2m ± 0.1m on. Microphone reference axis parallel to the ground and perpendicular point line CC '.

6.3.3 with the operating conditions By gear and test shall be specified in the initial steady speed

6.3.4 approaching AA 'line speed tolerance of ± 3%. When the front end of the vehicle approaching AA 'line, as far as possible to the motor controller or the throttle fully open, and held in the fully open position; When the trailing end of the vehicle reaches the line BB ', then, as soon as possible to return the throttle to idle position or motor controller will return to the closed position Set on. In the whole process of measurement, the vehicle should be traveling straight over the acceleration section keeping the longitudinal center plane of the vehicle as close to the line CC '.

6.3.4 Test line speed used

6.3.4.1 In the internal combustion engine as the power source of all-terrain vehicles 6.3.4.1.1 ATVs without transmission The test vehicle shall be the maximum power of the engine speed matches the speed of 3/4 steady speed, or to allow the engine governor 3/4 of the maximum speed of the speed matching a steady speed, or to 50km/h speed close to the line AA ', whichever is the lowest one speed. 6.3.4.1.2 equipped with hand (foot) automatic transmission ATVs If the test vehicle has 4 or less transmission gear ratio, you should use the second gear measurement. If the transmission has five or more gear ratios, third gear should be used for measurement. If you reach the BB 'line engine speed exceeds the maximum power speed, you should choose the 2 block 3 and block outside in close proximity to high gear Bit, this gear can without exceeding the value of the maximum power speed, reaches line BB 'on the runway. Should not be selected overdrive. If the car Vehicles with dual-stage main transmission, the selected gear ratio and the maximum speed gear of the vehicle should be consistent. The test vehicle shall be the maximum power of the engine speed matches the speed of 3/4 steady speed, or to allow the engine governor 3/4 of the maximum speed of the speed matching a steady speed, or to 50km/h speed close to the line AA ', whichever is the lowest speed. 6.3.4.1.3 with automatic transmission ATVs The test vehicle shall be 50km/h or three-quarters of its maximum speed stable speed approaching AA 'line, whichever is lower vehicle speed. in When you can choose from several forward range, they should choose between line AA 'and BB' line can produce the highest average acceleration of the vehicle gear. Only then it should not be used in braking, parking or similar low-speed movement of the selected gear position.

6.3.4.2 In electric power source for driving ATVs The test vehicle shall be 50km/h or three-quarters of its maximum speed stable speed approaching AA 'line, whichever is lower vehicle speed.

6.3.4.3 hybrid drive ATVs Manual switching mode power-driven ATVs provisions of

6.3.4.1 And

6.3.4.2 respectively performed. Powered automatic switching parties According to their type of vehicle reaches a predetermined line drive mode when a steady speed test, and shall be stated in the report.

6.4 Value Requirements

6.4.1 should adopt readings rounded to the nearest integer decibel. If the number after the decimal point is between 0 and 4, the figures after the decimal point should be rounded down; if it is between 5 and 9, the carry.

6.4.2 If the results of two consecutive measurements on the same side of the vehicle exceeds 2dB (A), the measurement is invalid.

6.4.3 Consider measurement accuracy uncertainty will each reading measured minus 1dB (A) as a measurement result.

6.4.4 The average of four measurements (to one decimal place) as that of the acceleration test with the maximum noise level.

6.4.5 hybrid all-terrain vehicle to take the larger of the two results as that of the acceleration test with the maximum noise level.

6.5 Measurement Record Measurement data and results of measurement conditions, that is test and measurement instruments and other technical parameters to fill in the Appendix A table. If there is Note the case, should fill in the "Additional Notes" column.