Improving the Combustion and Emissions of Direct Injection Compression Ignition Engines Using Oxygenated Fuel Additives Combined with a Cetane Number Improver

According to the fuel design concept, three oxygenated fuels including ethanol, dimethyl carbonate (DMC), and dimethoxy methane (DMM) were selected to mix with diesel fuel. Then, the effects of oxygen content and the cetane number of the blend fuels on diesel engine combustion and emissions were evaluated. The experiments were conducted on a four-cylinder high-speed diesel engine. The results show that, with the increase of the oxygen content in blend fuels, the ignition timing delays and the combustion duration shorten at different operating conditions, and the brake thermal efficiency improves from middle to full loads. The engine NOx emissions decreased at overall operating ranges when oxygenated fuels were added to the diesel fuel, and smoke emissions also improved for all oxygenated blend fuels except for ethanol−diesel blends at low and middle loads. In the case of the DMC−diesel blend fuel, when the oxygen content increased up to 15%, the smoke number decreased by 75%, and NOx emission improved by ...