|关键词: 双怠速法 过量空气系数 机动车 尾气 排放检测
|Analysis on Factors that Influence the Testing Result of Motor Vehicle Exhaust Emission by the Double Idle Speed Method
ZHONG Shiyu，ZHANG Su1,2
1. Jiangsu Jiecheng Motor Vehicle Inspection Co.，Ltd.，Kunshan，Jiangsu 215300，China;2. Jiangsu Environmental Monitoring Center，Nanjing ，Jiangsu 210036，China
|In view of the unqualified excess air ratio （λ） during the application of the double idle speed method，the article analyzed various factors affecting the testing results based on relevant standards and work practices. The testing results of λ were affected by a series of factors including poor air tightness of the sampling lines，not up to standard system response time，set up errors of the test software，unreasonable settings of the high idle speed，and selection criteria and operation errors caused by vehicle characteristics. These factors also affected the accuracy of the double idle speed method.
|Key words: Double idle speed method Excess air ratio Motor vehicle Vehicle exhaust Emission detection