Steady State Diesel Engine Performance and NOx Emissions with Selected Biofuels

Oxygenated biofuels such as biodiesel and ethanol blended with diesel fuel are biodegradable,non-toxic, renewable alternatives to imported petroleum diesel and their use not only creates new markets fordomestic agricultural products, but also greatly reduces particulate emissions. Unfortunately, biodiesel hasbeen shown to increase NOx emissions upwards of 10% compared to petroleum diesel. The objective of thisinvestigation was to evaluate the performance and NOx emissions of selected biofuels in a turbocharged andintercooled diesel engine using a steady state nonroad ISO 8-Mode test schedule. Test fuels includedtraditional No. 2 diesel and four biofuels comprising 100% soy methyl ester biodiesel, 2% biodiesel, 10%ethanol-diesel fuel, and 5% ethanol in biodiesel. Exhaust NOx emissions were monitored with a Horiba NOxanalyzer. Biodiesel fuel showed a 12% increase in NOx emissions while 2% biodiesel fuel increasedemissions 2.3%. The ethanol-diesel fuel blend reduced emissions by 2.7% and was highly sensitive to loadwith increased temperature and NOx emissions at light load. Addition of only 5% ethanol to biodieselsuppressed emissions, with only a 2.6% increase in NOx production. It was concluded that ethanol could actas an effective NOx emissions reducing additive.