Development of in-situ, full stream, Laser induced incandescence technique for measurement of transient soot emissions

The Laser Induced Incandescence technique (LII) is a sensitive optical method for reliable spatially and temporally resolved measurement of particulate matter (PM) concentration. This technique appears to be suitable for measurement of fast transient PM emissions, from diesel engines, which forms the main fraction of total emissions during standardized test cycles. However, the existing commercial LII devices require modifications in the exhaust gas flow, dilution, sampling cell, or it measure only in a partial stream. This article presents the development of a laser based optical setup - LII for rapid in-situ measurement of PM concentrations during the combustion process of a diesel production engine. The presented LII setup is suitable for direct in-situ, full stream, measurements of soot emissions without needs of dilution or a sampling cell. The focus of this paper is to measure static and transient PM emissions at tail pipe of an EURO 5 passenger car 2l diesel production engine by LII. A comparison of the LII approach with commercial devices based on photo-acoustic principle, opacity and filter blackening is also given. Results obtained from the fast in-situ LII device can help in better understanding of PM emissions and support dynamic emission modelling as well as control design for development of virtual PM sensors.