文档介绍：NVH Engine Cooling Fan Testing Specification & Target Items
(NVH发动机冷却风扇试验规范与项目目标)
Testing Specification – On Vehicle(试验规范——整车条件)
Measurement environment(试验环境)
Vehicle should be in an approximately free-field environment (either semi-anechoic chamber or outside with no major reflecting surfaces close by)
(将车辆放置于一个近似于自由场的环境中或者半消声室中或附近没有较大反射物体的户外环境中)
Measurement locations(测试位置)
3 external microphones, (三个置于车外的麦克风)
Front left / right at a distance of 1m and angle of 45 deg from the front centre, high(前端左侧与右侧的麦克风置于离麦克风阀帽中心1米,)
Front middle at a distance of 1m from the fan centre, high(前端中间的麦克风放置于在轴线方向距风扇中心1米,)
Operating conditions:(测试条件)
Fan at nominal high speed operating condition(风扇处于额定转速)
Engine idling (warm)(发动机暖机后怠速)
Data acquisition (数据要求)
Type: averaged (over 30s)(模式:平均噪声)
Sample rate: 25600 Hz(采样频率:25600赫兹)
Frequency resolution: 1Hz (频率分辨率:1赫兹)
Post-processing and plotting (数据处理与绘图)
Third octave spectrum(三分之一倍频程图)
Narrow band spectrum (0 to 1kHz)(狭带谱频率范围1至1千赫兹)
Testing Specification – Component in Semi-Anechoic Chamber
(测试规范——风扇单体在半消声室中)
Measurement environment(试验环境)
Semi-anechoic chamber(半消声室)
Component mounting(风扇单体带散热器及悬置)
As per supplier standard test. Cooling fan attached to radiator matrix and rigidly attached to a base(与每个供应商的标准试验一样,冷却风扇连接散热器总成严格的连接到台架上)
Measurement items(测试条款)
1 microphone at a distance