Particulate matter characteristics of a light-duty diesel engine with alternative fuel blends

Abstract

The non-volatile particle emission characteristics of alternative (rapeseed methyl ester and gas-to-liquid) diesel fuel blends were studied through an experimental investigation carried out on a light-duty common-rail diesel engine. A blend ratio of 10 vol % was chosen as the practical limit for biodiesels in this study, and the research focus was on the particle number concentration and size distribution with various injection strategies, in which the non-volatile emissions were measured using thermodilution. The particle morphology and mass, together with the related gaseous emissions, were measured and analysed. The results indicate that, without any engine modification, adding selected alternative fuels even at a low percentage could result in a favourable reduction in the number of particles and in a significant reduction in the total particle concentration in both the nucleation mode and the accumulation mode. The particle emissions of the three fuels demonstrated monomodal size distributions under most engine conditions tested, except for the engine idling case, which produced a bimodal size distribution. The influence of 10 vol % rapeseed methyl ester or gas-to-liquid diesel blends on the carbon monoxide and nitrogen oxide emissions is not significant. Nevertheless, using these diesel fuel blends may increase the total hydrocarbon emissions and may lead to high particulate matter emissions.