基于粒径分布的直喷汽油车颗粒物排放特性研究

Taking a national VI standard gasoline direct injection vehicle (GDIV) equipped with an exhaust particulate filter as the research object, the particle number (PN) emission concentration of different particle size ranges in the exhaust gas is measured by two instruments, namely, condensation particle counters (CPC) and electrostatic low voltatge impactor (ELPI+). The worldwide harmonized light vehicle test cycle (WLTC) cold-start test is carried out on a chassis dynamometer, and the test results show that in the ultra-high-speed section of the WLTC cycle test, the measurement results of ELPI+_29~2 500 nm is 1 order of magnitude higher than that of CPC_ 23~2 500 nm, with ELPI+_6~29 nm ultrafine particulate matter as the main body of PN emission accounting for up to 97.5%. Under hot start conditions, the high-speed section and ultra-high-speed section of the WLTC cycle show that the poor original exhaust of the engine and the continuous regeneration reaction of the gasoline engine particulate trap lead to large amount of ultra-fine particulate matter emission. To reduce the impact of vehicle particulate matter emissions on the environment and human health, it is necessary to conduct in-depth research on the particle size distribution of vehicle exhaust particles, and pay more attention to ultra-fine particles below 23 nm.