满足国Ⅳ排放法规的某柴油机改进设计和试验

摘要

为满足国Ⅳ排放法规的要求，在某国产二气门国Ⅲ柴油机基础上，改进了增压器及燃烧系统的设计：升级电控系统，设计燃烧室，优化喷油器、增压器，采用冷却废气再循环（EGR）和先进的后处理技术等；并对增压器、燃烧室、供油提前角、轨压、EGR进行排放优化选型及排放标定试验，测量了功率、扭矩、油耗、烟度、气体排放和EGR率、噪声等排放和性能参数，确定了该EGR系统及标定策略。对整机进行了车载故障诊断(OBD)标定。结果表明：这些措施改善了排放和性能；使该柴油机达到了国Ⅳ排放标准，怠速噪声由原来的74 dB降到70 dB。%A two-valve CN-III diesel engine was improved by designs and tests to meet the CN (China)-IV emission regulation. The improved designs involved upgrading the electronic control system, redesigning the combustion chamber, optimizing the injector and the turbocharger, adopting the exhaust gas recirculation (EGR) and the advanced after-treatment technology. The turbocharger, the combustion chamber, the fuel supply advance angle, the rail pressure and EGR were optimized and calibrated. The performance tests, the emission tests and the noise tests were completed. The EGR system and the calibration strategy were conifrmed by measuring and analyzing the parameters ofpower, torque, fuel consumption, smoke, emission, EGR rates, and the idle speed noise. The vehicle was calibrated by OBD (on-board diagnostic). The results show that the diesel engine meets the CN-IV emission regulation, and the idle speed noise decreased from 74 dB to 70 dB by improving emission and performance.