Abstract
In order to investigate forming processes and reducing techniques of ultra fine particles generated in diesel engine, reliable measurement tools should be developed. Laser induced incandescence (LII) has emerged as a promising technique for measuring both primary particle size and PM concentration. In this study, time-resolved LII method is applied to diesel engine exhaust for the measurement of primary particles size. A simple formulation is developed to relate particle size with time resolved LII signal. The data from time-resolved LII experiments are calibrated using Transmission Electron Microscope photograph for all the experimental conditions to investigate the difference between two measurements. The averaged difference for all the experiments is less than 4%.
For the measurement of PM concentration in diesel exhaust, the peak LII signal normalized by laser fluence is correlated with PM concentration qualitatively and calibrated using laser extinction method to obtain the absolute PM concentration.
Keywords:LII, Primary particle, Diesel engine, TEM, Laser extinction