Exhaust emissions from a Diesel engine fueled with transesterified waste olive oil

The exhaust emissions of a Diesel direct injection Perkins engine fueled with waste olive oil methyl ester were studied at several steady-state operating conditions. Emissions were characterized with neat biodiesel from used olive oil and conventional Diesel fuel. Results revealed that the use of biodiesel resulted in lower emissions of CO (up to 58.9%), CO2 (up to 8.6%, excepting a case which presented a 7.4% increase), NO (up to 37.5%), and SO2 (up to 57.7%), with increase in emissions of NO2 (up to 81%, excepting a case which presented a slight reduction). Biodiesel also presented a slight increase in brake-specific fuel consumption (lower than 8.5%) that may be tolerated due to the exhaust emission benefits. Combustion efficiency remained constant using either biodiesel or Diesel fuel. The proposed alternative for Diesel fuel could significantly decrease the enormous amount of waste frying oil, furthermore becoming less dependent on fossil oil imports and decreasing environmental pollution. (C) 2003 Elsevier Science Ltd. All rights reserved.