增压直喷汽油机细小颗粒物排放特性研究

A simultaneous test study on the particle number emission of particles whose diameters are greater than 23 nm and 10 nm was conducted on a China-6 certified, turbocharged, direct-injection gasoline engine vehicle without particulate filter using the worldwide harmonized light vehicles test cycle(WLTC) and RTS95 test cycle at ambient temperature(23℃), and real drive emission(RDE) test cycle at low temperature(0℃), to research the emission characteristics of sub-23 nm particles from turbocharged direct-injection gasoline engine vehicles. The results showed that the emissions of numbers of particles whose diameters are above 10 nm were 32.4%, 30.4% and 15.6% higher than those of China-6 standard required particles whose diameters are above 23 nm in the ambient-temperature WLTC, ambient-temperature RTS95 test cycle and low-temperature RDE cycle respectively. Without particulate filter, the percentage of sub-23 nm particles in the total particle emissions increased significantly during harsh accelerations, decelerations, and idle conditions, but it was very low in the cold-start and warm-up stages. Sub-23 nm particles mainly formed after the vehicle was fully warmed-up and the three-way catalyst converter was fired. Lower ambient temperature was not beneficial to the formation of sub-23 nm particles.