Experimental investigation on internal combustion engine for micro-cogeneration application fuelled with alternative fuels: energy recovery, performance and pollutants formation

This work is aimed to characterize in terms of energy recovery, combustion characteristics and pollutant emissions a small compression ignition engine for micro-cogeneration application fuelled with blended and pure biodiesel. The engine under investigation was a three-cylinder, 1028 cc of displacement, equipped with a common-rail injection system. The engine was fuelled with diesel, a blend of 20% v/v rapeseed methyl ester (RME), a blend of 50% v/v RME and pure RME. Tests were performed at different operating conditions. The quantity and the quality of the waste heat energy, which can be used for cogeneration purpose, were evaluated through energy and exergy analyses, respectively. Combustion process was studied by means of thermodynamic analyses. The environmental impact of the engine in terms of combustion noise and pollutant emissions was investigated. In particular, an in-depth understanding of pollutants formation was provided by non-intrusive optical diagnostics application. Results reported in this thesis could be useful for the development of a new technology of engine based micro-cogeneration system working at different engine speeds and loads.