1、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)1. 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
2、)（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 bonnet centre, 1.6m high（前端左侧与 右侧的麦克风置于离麦克风阀帽中心 1米，左右分别 45度离地高 1.6米处）Front middle at a distance of 1m from the fan cen
3、tre, 1.6m high（前端中间的麦克风放置于在轴线方向距风扇中心 1米，与地面距离 1.6米处）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-
4、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）2. 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
5、 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 of 1m from the centre of the fan, on the fan rotational axis（一个麦克风置于风扇轴线上，离风扇中心 1米处）Fan operating speed (if possible)（如果可能的话，操纵风扇转速）Opera
6、ting condition（测试条件）Fan at nominal high speed operating condition (operating voltage to be checked for initial Ford Focus measurements and kept constant for all further measurements)（风扇处于额定转速下，加以和福克斯相同的额定电压并保持稳定以便下一步的测量）Data acquisition and presentation（数据处理）Type: averaged (over 30 seconds) （模式：平均噪声
7、）Overall level in dB(A) （总声压级）Third octave bands (at least 100Hz to 20 kHz)（三分之一倍频程图 频率范围至少 100赫兹至 20000赫兹）3. Target item summary（目标概述）On vehicle:（整车中） Average overall level of 3 microphone measurements（三个麦克风的平均总声压级） Average level of blade passing frequency peak（叶片通过频率平均值）Component:（部件） Overall level dB(A)（总声压级） Level of third octave band containing blade passing frequency （三分之一倍频程图 包括叶片通过频率）(Blade passing frequency = fan speed (rpm) x number of blades on fan / 60)（叶片通过频率=风扇转速 x叶片个数/60）
