Steady State Diesel Engine Performance and NOx Emissions with Selected Biofuels

Abstract

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 for domestic agricultural products, but also greatly reduces particulate emissions. Unfortunately, biodiesel has been shown to increase NOx emissions upwards of 10% compared to petroleum diesel. The objective of this investigation was to evaluate the performance and NOx emissions of selected biofuels in a turbocharged and intercooled diesel engine using a steady state nonroad ISO 8-Mode test schedule. Test fuels included traditional 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 NOx analyzer. Biodiesel fuel showed a 12% increase in NOx emissions while 2% biodiesel fuel increased emissions 2.3%. The ethanol-diesel fuel blend reduced emissions by 2.7% and was highly sensitive to load with increased temperature and NOx emissions at light load. Addition of only 5% ethanol to biodiesel suppressed emissions, with only a 2.6% increase in NOx production. It was concluded that ethanol could act as an effective NOx emissions reducing additive.