查看文章

Diesel engines offer higher fuel efficiency, but produce more exhaust particulate than conventional gasoline engines. Diesel particulate filters are presently the most efficient means to reduce these emissions. These filters typically trap particles in two basic modes: at the beginning of the exposure cycle the particles are captured in the filter holes, and at longer times the particles form a “cake” on which particles are trapped. Eventually the “cake” is removed by oxidation and the cycle is repeated. We have investigated the properties and behavior of two commonly used filters: silicon carbide (SiC) and cordierite (DuraTrap^® RC) by exposing them to nearly-spherical ammonium sulfate particles. We show that the transition from deep bed filtration to “cake” filtration can easily be identified by recording the change in pressure across the filters as a function of exposure. We investigated the performance of these filters as a …