Experimental Investigation on Combustion and Emission of a Common Rail Diesel Engine Fueled with Methyl-Ethyl-Ketone as Port Fuel

In this study, we investigated the methyl-ethyl-ketone/diesel (MEK/diesel) partially premix-charged compression-ignite-based combustion in a common-rail 4-cylinders compressed engine. The static engine was modified with a MEK port-fuel injecting unit and electronic controlling equipment. An experiment was conducted under various loads, brake mean effective pressures (BMEPs; 4.2, 7.0, and 9.8 bar), a speed of 1,600 rpm achieved by varying the MEK energy substitution (0–15%) conducted with exhaust gas recirculation (EGR) (0–15%), and three port-fuel ratios. The results indicated that, at 4.2 bar BMEP, the combustion characteristics of the diesel engine remained nearly unchanged regardless of the port-fuel ratio. At a BMEP of 7 bar, the peaking heat releasing rate(HRR) of MEK15, MEK10, also MEK5 increased by 4.12, 2.11, and 1.87%, respectively, and the ignition delay (ID) was extended. At the given EGR rates, the peak HRR increased evidently when the substitution rate rose. The peaking temperature cylinder decreased with the increase in the mass of MEK. Owing to the effect of MEK on the ID, there was no significant transformation in the premixed ratio despite the substitution rate rise. At a BMEP of 9.8 bar, the NO and NOx emissions of MEK5, MEK10, and MEK15 decreased by 12.9 and 6.8%, 14.5 and 9.8%, and 17.3 and 9.7%, respectively. Thus, the use of MEK as the fuel eliminates the trade-off between NOx and soot. We recommend an EGR of 10% and a higher MEK energy ratio of 15% for this type of engine.