车用发动机燃用生物柴油的颗粒数量排放

Particle number emission from a vehicle diesel engine with biodiesel fuel

研究了车用电控共轨柴油机燃用生物柴油燃料的排放特性,重点探讨了排气颗粒数量的尺寸分布及浓度特性。所用4种燃料分别为纯柴油、纯生物柴油、生物柴油掺混体积配比分别为10%和20%的B10、B20混合燃料。结果表明:与柴油相比,使用B10和B20燃料的气态排放变化较小,纯生物柴油的HC和NOx排放有明显变化。柴油机排气颗粒数量的尺寸分布呈现单峰或双峰对数分布。生物柴油降低了聚集态颗粒的数量浓度,同时增加了核态颗粒的数量浓度。随着生物柴油配比的增加,发动机排气颗粒总数量浓度大都呈持续上升趋势,在高负荷下更为明显。但在低负荷燃用低配比生物柴油燃料时,聚集态颗粒数量的影响变大。

Biodiesel fuels were used on a direct injection, high pressure common-rail diesel engine. Effects of biodiesel on emissions of exhaust gas and particle number of the diesel engine are studied using an AVL AMA i60 and an Engine Exhaust Particle Sizer （EEPS）, respectively. The neat biodiesel, two different blends of petroleum diesel/biodiesel （10% and 20%, v/v biodiesel blends）, and the base petroleum diesel （B100, B10, B20 and B0 fuels） were tested without engine modification. For all test fuels, the particle number and size distribution show unimodal or bimodal log-normal distribution. With the biodiesel blend ratios increasing, the number of nucleation mode particles increases and accumulation mode particles decreases, and the total particle number ascend at most engine operating conditions, especially at higher engine load. Nucleation mode particles dominates the total particle number, and accumulation mode particles shows more effects at lower engine load with lower blend ratios of biodiesel fuel.