Performance, Efficiency, and NOX Emissions of a Compact Diesel Tractor Fueled with D2, B20, and B100 Under Steady-State Loads

Abstract

This study compared power take-off (pto) power performance, fuel efficiency, and NOX emissions of a 23.9-kW compact utility tractor fueled with No. 2 petroleum diesel (D2), a 20% biodiesel blend (B20), and neat biodiesel (B100) under two load conditions. Three steady-state (1h) tests were conducted with each fuel at both rated pto speed (540 rpm) and at peak torque (18 total tests). At rated pto speed, there were significant (p < 0.05) differences between the fuels for pto torque and power (D2 > B20 > B100) and pto-specific fuel consumption (D2 = B20 < B100); there were no significant differences for pto-specific NOX emissions, although specific NOX emissions trended higher as the biodiesel content of the fuel increased. At peak torque, there were significant differences (p < 0.05) between B100 and the other two fuels for pto torque and power (D2=B20>B100) and for pto-specific fuel consumption, thermal efficiency, and NOX emissions (D2=B20<B100). While not statistically significant, observed specific NOX emissions were also higher for B20 than for D2 at peak torque. The results indicate that performance and fuel efficiency were similar when the tractor was fueled with either D2 or B20, especially at peak torque. Fueling with B100 resulted in significantly less pto power and torque and higher specific fuel consumption under both load conditions and significantly higher specific NOX emissions at peak torque. Observed specific NOX emissions trended higher as the biodiesel content of the fuel increased for both load conditions.