Journal of Agricultural Systems, Technology, and Management Volume 24 January 2013 Hunt, C. L., Johnson, D. M., & Edgar, D. W. (2013). NO X Emissions and Performance of a Compact Diesel Tractor Fueled with Emulsified and Non-Emulsified Biodiesel. Journal of Agricultural Systems, Technology, and Management, 24, 12-22. 12 NO X Emissions and Performance of a Compact Diesel Tractor Fueled with Emulsified and Non-Emulsified Biodiesel Chris L. Hunt 1 , Donald M. Johnson 2 , Don W. Edgar 3 1 Graduate Assistant, University of Arkansas, Agricultural Systems Technology Management, 235 Agriculture Building, Fayetteville, AR 72701. Phone: 479-575-2035 FAX: 479-575-2610 Email:clhunt@uark.edu 2 Professor, University of Arkansas, Agricultural Systems Technology Management, 235 Agriculture Building, Fayetteville, AR 72701. Phone: 479-575-2035 FAX: 479-575-2610 Email: dmjohnso@uark.edu 3 Associate Professor, University of Arkansas, Agricultural Education, 235 Agriculture Building, Fayetteville, AR 72701. Phone: 479-575-2035 FAX: 479-575-2610 Email: dedgar@uark.edu Abstract A John Deere 3203 compact utility tractor (23.9 kW rated engine power) was fueled with No. 2 petroleum diesel (D2), neat biodiesel (B100), and a 10% water-in-biodiesel emulsion (Em-B100) to determine the effects on exhaust gas temperature, oxides of nitrogen (NO X ) emissions, power, specific fuel consumption, and thermal efficiency under two load conditions (rated engine speed and peak torque). At rated engine speed, fueling with D2 resulted in statistically significantly (p < .05) higher exhaust gas temperatures than B100 and Em-B100; however, there were no significant differences in power take-off (PTO) specific NO X emissions. Specific fuel consumption was statistically significantly lower for D2 when compared to B100 and Em-B100, but there were no significant differences in thermal efficiency among fuels. For peak torque tests, exhaust gas temperatures were statistically significantly lower with Em-B100 than with D2 or B100. PTO specific NO X emissions with Em-B100 were equal to D2 and statistically significantly lower than B100. There was no significant difference between B100 and Em-B100 in specific fuel consumption, but specific fuel consumption for both fuels was statistically significantly higher than D2. However, fueling with B100 and Em-B100 resulted in statistically significantly higher thermal efficiencies as compared to D2. At both rated engine speed and peak torque, there were statistically significant decreases in PTO power as fuel was switched from D2 to B100 to Em-B100. These results indicate that Em-B100 has the potential to decrease NO X emissions and increase engine thermal efficiency under heavy load conditions; however, NO X reduction with Em-B100 will be at the expense of decreased power at both rated engine speed and peak torque. Keywords: biodiesel, engine performance, emulsified biodiesel, fuel efficiency, oxides of nitrogen, power