【摘要】 本文根据实测的催化器入口、出口温度及HC排放浓度 ,结合示功图对电喷汽油机冷起动时HC排放量在台架上进行了模拟分析 ,认为起动过程以节气门突开为界 ,可划分为 2个阶段。其中HC排放主要集中在开始起动到节气门开这一段时间内 ,而这段时间的HC排放又以起动后最初几秒钟为主。适当减稀空燃比 ,促使缸内发生不完全燃烧 ,则未燃HC在排气管内可继续氧化 ,使得最终排出的HC量降低 ,并有利于催化剂的起燃。更多还原

【Abstract】 Experiment is carried out on an engine dynamometer bench for simulating the cold start of port injected gasoline engines.Based on the measured temperatures and HC emission at the inlet and outlet of the catalytic converter as well as cylinder pressure,how to achieve minimum catalytic converter out HC emissions prior to catalyst light off has been discussed.In this experiment,the cold start period is divided into two stages referred to the opening of the throttle valve.Most of the HC are emitted in the first stage,i.e.from cranking to the opening of the throttle valve.And the HC emitted in the first several seconds contribute most to this stage.Proper leaner A/F could result in incomplete combustion in the combustion chamber and the unburned HC continue to be oxidized in the exhaust manifold,which could contribute to the reduction of HC emission and quicken the light-off of the catalyst.更多还原