Abstract:The effects of diesel oxidation catalyst on the characteristics of particle was studied on a heavy duty diesel engine. The results show that particle mass concentrations of measuring point after DOC decrease compared to those before DOC, and the decreasing range reduces with the increase of engine speed, but differs insignificantly with the increase of engine load. When the engine is operating at full load, the conversion rates of total particles, nucleation mode particles and accumulation mode particles decline with the increase of engine speed, with an average conversion rate of 21.5%, 26.2% and 15.4%, respectively. At an engine speed of 1 400 r·min-1, the conversion rates of total particles, nucleation mode particles and accumulation mode particles decrease first and then increase with the increase of engine load, with an average conversion rate of 34.6%, 38.8% and 27.3%, respectively. The particle conversion rates of DOC to nucleation mode particles are higher than those of accumulation mode particles, and reach the peak when the particle size range from 9 to 12 nm. However, the particle conversion rate for the rest of the particle size vary from 20% to 40%.
