Detailed Analysis of the Effects of Biodiesel Fraction Increase on the Combustion Stability and Characteristics of a Reactivity-Controlled Compression Ignition Diesel-Biodiesel/Natural Gas Engine

A single-cylinder marine diesel engine was modified to be operated in reactivity controlled compression ignition (RCCI) combustion mode. The fueling system upgraded a common rail fuel injection system. Natural gas (NG) used as port injection, and diesel/sunflower methyl ester biodiesel mixture for direct injection. fraction of the changed from 0% (B0; 100% diesel) 5% (B5) 20% (B20) while keeping total energy input into constant. objective understand impacts increased on characteristics stability, emissions, knocking/misfiring behavior, all other influential parameters results showed that nitrogen oxides (NOx) emissions B5 B20 without need any after-treatment devices were lower than NOx emission limit Euro VI stationary regulation. decreased by more 70% compared baseline. Significantly unburned hydrocarbons (UHCs) carbon monoxide (CO) produced when (DFI). also using instead B0 led an increase 18% 13.5% UHCs 88.5% 97% CO respectively. Increasing reduced maximum in-cylinder pressure 3% 10.2%, respectively, B0. Combustion instability is characterized coefficient variation (COV) indicated mean effective (IMEP), which measured 4.2% 4.8% 1.8% Therefore, resulted up 34.9% instabilities, 18.5% baseline case. tendency knocking 13.7% 4.3% B20. case (B0) had no misfiring cycle. some cycles, but cycle observed. Moreover, historical cyclic analysis data dispersions DFI. This study shows potential replacement NG/diesel RCCI engines. can effectively reduce intensity combustion. However, needs monitored.