Evaluation of a diesel engine fueled with hazelnut biodiesel/dibutyl maleate blends under DOC and SCR aftertreatment: performance, combustion, and emission analysis

This study investigated the effects of fuel blends consisting of diesel, hazelnut oil biodiesel, and DBM, designated as diesel, B50, B50DBM5D45, B50DBM10D40, and B50DBM15D35, on the combustion, performance, and emission characteristics of a diesel engine equipped with DOC-SCR aftertreatment. Experiments were conducted at 1800 rpm under engine loads of 10.98, 16.48, and 21.97 Nm. In-cylinder pressure, HRR, ID, CA50, CD, IMEP, MPRR, RI, COVIMEP, EGT, SFC, ITE, CO, CO2, HC, and NOx were evaluated. Compared with diesel, the biodiesel-DBM blends exhibited shorter ID due to their higher oxygen content. The B50DBM10D40 blend produced the highest in-cylinder pressure and HRR at the 10.98 and 21.97 Nm loads, whereas the B50 exhibited the highest values at the 16.48 Nm load. The B50DBM15D35 achieved an ITE of 32.8% at the 16.48 Nm load, comparable to that of diesel, although oxygenated fuels increased SFC. Oxygenated blends reduced engine-out CO emissions but increased NOx emissions, while HC emissions were strongly dependent on the DBM ratio. The integrated DOC-SCR system completely eliminated CO emissions under all tested conditions. In addition, at a load of 21.97 Nm, B50DBM10D40 decreased the measured volumetric CO2 concentration at the SCR outlet by up to 58.58% and achieved a maximum NOx conversion efficiency of 69.24%.