Effects Of Combustion Mode On Exhaust Particle Size Distribution Produced By An Engine Fueled By Dimethyl Ether (dme)

摘要

Exhaust particle (10-487 nm) number size distributions (NSDs) from an engine fueled with dimethyl ether (DME) for three combustion modes [compression ignition direct injection (CIDI), homogeneous charge compression ignition (HCCI), and compound charge compression ignition combustion (CCCI)] were tested and compared. The results indicated that the NSD for various combustion modes showed similar unimodal structure with a nucleation mode at all test engine conditions. The exhaust particle geometric mean diameters of CCCI and HCCI were within the same range, and they were around 4-7 nm bigger than those of CIDI. Under the same engine condition (1100 revolutions/min, 20% of full load), the total exhaust particle number concentrations for CCCI (r_p = 0.18-0.85) were slightly lower than those of HCCI but 20.0-29.3% higher than those of CIDI. For CCCI, the total number decreased with the increase of the load at the same premixing ratios but increased significantly with the increase of the premixing ratio at the same engine conditions.