Evolution of deep-bed filtration of engine exhaust particulates with trapped mass:

Size-resolved particle mass and number concentrations were obtained from different operating conditions using a spark-ignition direct-injection engine and a heavy-duty diesel engine. Particle mass versus mobility diameter results obtained for the engines showed weak dependence on the operating condition. The particle mass–mobility data enabled the use of an integrated particle size distribution method to estimate the particulate matter mass concentration in the exhaust stream. Average mass concentrations determined with the integrated particle size distribution method were 77−32+47% of the gravimetric measurements performed using Teflon filters. Despite the relatively low elemental carbon fraction (∼0.4 to 0.7), the integrated particle size distribution mass for stoichiometric spark-ignition direct-injection exhaust was 83% ± 38 % of the gravimetric measurement. Exhaust from the spark-ignition direct-injection engine was also used to perform wall-scale filtration experiments on identical cordierite filter...