本文件规定了一种通过安装测力计的半消声室测量M和N类道路车辆发出的噪声的工程方法。 本规范旨在实现在半消声室内测试道路车辆外部噪声与ISO362-1. 本文件提供了室内试验的所有必要规范和程序，以获得与当前型式认证试验中典型的测量值逐次变化相当的结果。 本文件提供了一种设计用于满足简单性要求的方法，只要其与车辆运行条件下结果的再现性一致。 注意事项1.通过该方法获得的结果给出了在规定试验条件下发出的噪声的客观测量。有必要考虑这样一个事实，即对不同类别机动车的噪声烦扰度的主观评估不仅仅与声音测量系统的指示有关。由于烦扰度与个人人类感知、生理人类条件、文化和环境条件密切相关，因此存在很大的差异，因此烦扰度不可用作描述特定车辆状况的参数。 注意事项2.如果在不符合本文件规定要求的房间内进行测量，则所得结果可能与使用规定条件的结果有所偏差。

This document specifies an engineering method for measuring the noise emitted by road vehicles of categories M and N by using a semi anechoic chamber with a dynamometer installed. The specifications are intended to achieve an acoustical correlation between testing the exterior noise of road vehicles in a semi anechoic chamber and outdoor testing as described in ISO 362-1. This document provides all necessary specifications and procedures for indoor testing to obtain results which are comparable to typical run-to-run variations of measurements in today’s type approval tests. This document provides a method designed to meet the requirements of simplicity as far as they are consistent with the reproducibility of results under the operating conditions of the vehicle. NOTE 1   The results obtained by this method give an objective measure of the noise emitted under the specified conditions of test. It is necessary to consider the fact that the subjective appraisal of the noise annoyance of different classes of motor vehicles is not simply related to the indications of a sound measuring system. As annoyance is strongly related to personal human perception, physiological human conditions, culture, and environmental conditions, there is a large variation and annoyance is therefore not useful as a parameter to describe a specific vehicle condition. NOTE 2   If measurements are carried out in rooms which do not fulfil the requirements stated in this document, the results obtained can deviate from the results using the specified conditions.