为了准确测得机动车高温尾气中的COx、NOx、THC等气体成分,基于旋风分离器原理,详细讨论了高温尾气的预处理方案；以微粒物过滤室、 旋风分离器、阻液器和膜式干燥器为主要器件,设计了改进型旋风分离器和车载式高温尾气预处理采样气路；利用微粒物过滤室两次去杂、金属螺 旋管降温、旋风分离器去水去杂、阻液器去水、膜式干燥器去水,在不改变尾气气体成分和含量的情况下,提高了样气净度；实验结果表明,预处 理后的样气,相对湿度小于2.5%,温度低于40℃,所含颗粒物直径小于5 μm,且含量极少,满足车载式机动车尾气气体成分分析模块的要求。

To measure COx, NOx, THC and other gas components of vehicle high temperature exhaust accurately, based on the principle of cyclone, the high temperature exhaust pretreatment regimen is discussed in detail. An improved cyclone and vehicular high temperature exhaust pretreatment gas circuit are designed, taking particulate filter chamber, cyclones, fluid resistance and membrane dryers as the main device. Particulate filter chamber is used to remove dust, metal spiral is used to drop temperature, cyclone is used to remove water and dust, resistance dispenser is used to remove water and membrane dryer is used to remove water. Without changing the exhaust gas composition and content, the gas clarity is improved. Experimental results show that the relative humidity of pretreatment gas is less than 2.5%, temperature is below 40℃, particles diameter is less than 5 μm and the content is extremely low. The sampling pretreatment system meets requirements of motor vehicle exhaust composition analysis module.