POMDME-diesel blends: Evaluation of performance and exhaust emissions in a single cylinder heavy-duty diesel engine

Oxygenated fuels produced from methane-based products are characterized by strong capability of reducing soot at the exhaust of internal combustion engines. In addition some oxygenates are characterized by similar physical properties to diesel thus not requiring substantial modifications to the engine infrastructure. Therefore, their production on industrial scale could be proposed to obtain blends with commercial diesel once results on emission reduction and fuel economy would have been experienced.In the present paper different poly (oxymethylene) dimethyl ethers (POMDME) in diesel blends (5 and 10%) have been investigated in a single cylinder heavy duty diesel engine in order to achieve a complete overview of their impact on engine performance and exhaust emissions. In addition to exhaust soot and gas analysis, the kL calculation has been carried on in order to discuss further details regarding the soot formation/oxidation dominant phases for the different fuels. For this purpose a miniaturized optical light probe (OLP) has been mounted directly in the engine combustion chamber.The comparison between the POMDME diesel blends and commercial diesel has shown a significant reduction in soot emissions, close to 35%. Moreover no significant increase in NOX emissions has been found, highlighting as molecular oxygen can be not crucial (at least up to the percentages considered in the present paper) for this pollutant in a premixed plus diffusive combustion mode.