In-Cylinder Measurement of Particulate Number Density and Size

A technique to determine time and space resolved particulate number density and size in the cylinder of an operating diesel engine is described and sample data presented. Basically the technique uses Mie scattering of a laser beam passed through the jet of gases leaking through a 0.015 diameter orifice inserted into the combustion chamber. Number density and size are inferred from measurements of scattering as a function of angle of scattering. The data show a linear relationship between exhaust measurements using this technique and Bosch smoke meter readings as well as an approximately linear relationship between in-cylinder measurements of number density and mass measurements made by collecting particulates flowing through the 0.015 in, orifice on a filter.