Based on heavy chassis dynamometer, an experimental study was conducted in diesel buses compliant with China Ⅲ,Ⅳ,Ⅴ emissions standards respectively, fueled with three different blends of petroleum diesel/biodiesel (0%,5%and 10%, V/V biodiesel blends), which investigated the characteristics of particulate matter (PM) emission under CCBC driving cycle. Results of study showed that the total PM number and mass emission from China Ⅴ bus respectively decreased by 68.1%,56.2%,57.5% and 52.7%,64.8%, 88.5% compared to China Ⅲ bus. When compared to China Ⅳ bus, the PM mass emission decreased by 43.0%, 47.3% and 42.1%, while the number increased by 4.0%,7.6% and 14.7%. The nucleation mode PM emission of China Ⅲ bus was mainly from high-speed driving condition, while China Ⅳ and Ⅴ buses were from middle-low speed. The accumulation mode PM emissions of China Ⅲ, Ⅳ and V buses were all mainly from middle-low speed driving conditions. In relatively lower speed conditions, compared to China Ⅲ bus, the nucleation mode PM emissions of China Ⅳ and Ⅴ buses obviously decreased, so was accumulation mode PM. Compared to China Ⅳ bus, emission of China Ⅴ bus did not improve obviously and the nucleation mode PM emission even increased. In high-speed driving condition, the nucleation mode PM emission from China Ⅲ bus increased dramatically, while those from China Ⅴ and Ⅳ buses slightly increased. Meanwhile, the accumulation PM number and mass emission of China Ⅳ bus was obviously higher than those of China Ⅴ and Ⅲ buses. When fueled with B10, the relatively bigger sizes PM emission of China Ⅲ bus deteriorated rapidly, indicating that China Ⅲ bus was not suitable for fuel with high blending ratio of biodiesel.
Keywords: China city bus driving cycle (CCBC); biodiesel; diesel bus; emission standard; particulate emission.