A comparative study of combustion and emission characteristics of dual-fuel engine fueled with diesel/methanol and diesel-polyoxymethylene dimethyl ether blend/methanol

In this study, a comparative study of the combustion characteristics and performances of a dual-fuel engine fueled with diesel/methanol and diesel-polyoxymethylene dimethyl ether blend/methanol was conducted. All the experiments were conducted on a heavy-duty common rail diesel engine at an engine speed of 1800 r/min. The engine loads were fixed at low, medium, and heavy loads, with the brake mean effective pressure at 0.42 MPa, 0.7 MPa and 0.9 MPa, respectively. Methanol substitution ratio (MSR) was defined as the torque output contributed by methanol to the total torque output, and in this study, three MSRs (0 %, 20 %, and 40 %) were defined. Diesel-polyoxymethylene dimethyl ether (PODE) blend was defined as P50 (50 % diesel and 50 % PODE by volume) to clarify the effect of PODE addition on engine performance. The results showed that the dual-fuel engine fueled with P50/methanol had a higher peak cylinder pressure, lower first peak heat release rate (HRR), and higher second peak HRR than the dual-fuel engine fueled with diesel/methanol. Both the ignition delay and combustion duration of the dual-fuel engine decreased when the pilot fuel injection changed from diesel to P50. Moreover, both NOx emissions and particulate matter produced by the P50/methanol engine were lower than those produced by the diesel/methanol engine for the specific MSR and engine load. (C) 2021 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.