摘要
试验针对车用发动机在WHTC循环试验中的NO_x污染物排放,根据试验程序和测量方法建立了NO_x排放的数学计算模型,并通过理论方法对模型中测量重复性、稀释排气流量、排气污染物浓度、NO_x湿度校正系数和实际循环功等各种参数的相对标准不确定度进行了分析,最终得到了NO_x排放的不确定度评定结果。结果表明,WHTC试验NO_x比排放量的合成相对标准不确定度为5%,满足标准法规对NO_x测量的精度要求。从不确定度的评定过程可以看出,在试验时要保证发动机和后处理系统状况良好,工作稳定,并在日常保养时加强定容稀释系统、排放分析系统和发动机测功机系统的标定和维护工作。
This test focuses on NOx emissions during the WHTC cycle test from automotive engine. According to the test procedure and measurement method, the mathematics model of NOx emissions was established. Relative standard uncertainty of measurement repeatability, dilute exhaust flow, NOx emissions concentration, humidity correction coefficient, actual circulation work and so on various parameters were analyzed by means of theoretical model. Finally evaluation results of uncertainty of NOx emissions were obtained. Results show that the synthesis of relative standard uncertainty of NOx emissions during WHTC test was 5%, satisfying the requirement of the standards and regulations for NOx measurement precision. Seen from the process of uncertainty evaluation process, the engine and after-treatment system should be in good condition and work stable in the test. The calibration and maintenance work of constant volume dilution system, emission analysis system and engine dynamometer system should also be strengthened during daily maintenance.
出处
《小型内燃机与车辆技术》
2015年第6期18-23,37,共7页
Small Internal Combustion Engine and Vehicle Technique
作者简介
张凡（1982-），男，博士，高级工程师，主要研究方向为排放测试技术。
