Engine Performance and Emissions from Dual Fuelled Engine with In-Cylinder Injected Diesel Fuels and In-Port Injected Bioethanol 2009-01-1853

Biofuels development and specification are currently driven by the engine (mainly gasoline- and diesel-type) technology, existing fossil fuel specification and availability of feedstock. The ability to use biofuels with conventional fuels without jeopardising the standard fuel specifications is a very effective means for the implementation of these fuels. In this work the effect of dual fuelling with in-cylinder injected ULSD fuel or synthetic second generation biofuels (a Gas-To-Liquid GTL fuel as a surrogate of these biofuels as its composition, specifications and production process are very similar to second generation biofuels) and with inlet port injected bioethanol on the engine performance and emissions were investigated. The introduction of anhydrous bioethanol improved the NOx and smoke emissions, but increased total hydrocarbons and carbon monoxide. The improvement in the engine emissions was magnified when the engine was run with in-port injected bioethanol and in-cylinder injected GTL, compared to the engine operation only on diesel fuel. Although the small bioethanol additions at the inlet port did not significantly affect the combustion patterns (e.g. ignition delay, cylinder pressure, heat release rate, combustion phase), the engine efficiency from the dual fuelled operation was slightly reduced at low loads due to inefficient bioethanol combustion. As the engine load increases, bioethanol combustion and engine efficiency were improved.