Laser diagnostics of soot formation by alternative fuels

Abstract

It has been reported in previous work that the reduction of particulate matter (PM) emissions from diesel engines is impacted by the molecular structure of additives and blended oxygenates. However, due to the physical and chemical complexity of the underlying processes, characterization of combustion-generated soot particles and the effects thereupon of different fuel composition are difficult to achieve. Laser diagnostics on a simple, optically accessible burner is proposed, to aid interpretation of observations in engine tests on the effect of molecular structure of additives on the sooting propensities of hydrocarbon fuels. We present measurements of the soot and poly-aromatic hydrocarbons (PAH) distributions conducted by means of Laser-induced incandescence (LII) and planar Laser-induced fluorescence (PLIF) of several kinds of blends on a stationary co-flow flame. Moreover, a comparison is made to earlier engine emission characteristics of the same blends