SOOT MASS CONCENTRATION MEASUREMENTS IN DIESEL-ENGINE EXHAUST USING LASER-INDUCED INCANDESCENCE

Simultaneous measurements of laser-induced incandescence (LII) and ela stic scattering from soot particles in diesel engine exhaust have been made, The Ln signal scaled linearly with the mass concentration of th e non-volatile particulate mass fraction over the entire range of engi ne operating loads, Over this range of conditions, the volume mean dia meter of the soot particles varied from 0.07 to 0.11 mu m, but the siz e change did not appear to affect the signal response. The scattering response did not scale linearly with the mass concentration of soot. M ass concentrations of 0.2 mg/m(3) were easily detectable, with even lo wer values possible. Additional techniques for determining the volatil e fraction of particulate mass are described.