George W. Wardlow

Effects of No.2 diesel, B-20 soy biofuel blend, and B-100 soy biofuel on performance, efficiency, and emissions in a compression ignition tractor

Tests were conducted in the fall of 2006 on a John Deere 3203 diesel tractor to determine the differences in specific fuel consumption, power take-off (PTO) torque, PTO power, thermal efficiency, and oxides of nitrogen (NOx) emissions between No. 2 diesel (D2), 20% biodiesel (B20), and 100% biodiesel (B100). Four, 1-hours tests were conducted on each fuel. The results indicated no statistically significant differences (p<.05) between D2 or B20 on any variable of interest. However, B100 resulted in significantly (p<.05) increased specific fuel consumption and thermal efficiency, and decreased PTO torque and PTO power over both D2 and B20. These data suggest that farmers could switch from D2 to B20 without any performance loses, but a switch to B100 would result in the use more fuel, and a loss of power and torque.

NOX Emissions and Performance in a Single-Cylinder Diesel Engine with Emulsified and Non-Emulsified Fuels

A single-cylinder diesel engine (4.8 kW) was fueled with petroleum diesel, 20% biodiesel (B20), neat biodiesel (B100) and 10% (by volume) emulsified D2 (Em-D2), B20 (Em-B20) and B100 (Em-B100) to determine their effects on exhaust gas temperature, brake specific NOX emissions, brake power, brake specific fuel consumption, and brake thermal efficiency at four engine speeds (3600, 3300, 2900, and 2400 rpm). Four replications were conducted at each level of fuel and speed (24 tests).Compared to D2, fueling with E-D2 resulted in similar NOX emissions and decreased power and fuel and thermal efficiencies. Fueling with Em-B20 and Em-B100 significantly reduced NOX emissions relative to both non-emulsified base fuels and to D2.Fueling with E-B20 significantly reduced power and fuel and thermal efficiencies (compared to B20), while Em-B100 resulted in some improvements in power and fuel and thermal efficiencies.

Effectiveness of a Biodiesel Education Program for Secondary School Students

A 2 h educational program on biodiesel production, quality, performance, and emissions was developed and delivered to students (N = 199) in 14 classes at eight public secondary schools. The program was conducted over two days in each class and consisted of a lecture-discussion (Day 1) and an engine performance demonstration and discussion (Day 2). A pre-test post-test design was used to measure changes in students’ knowledge and perceptions of biodiesel as a result of the educational program. Students’ knowledge of biodiesel increased significantly (p<.0001), with post-test knowledge scores increasing 107% relative to pre-test knowledge scores (61.5% vs. 30.1% correct). Students’ initial perceptions of biodiesel were fairly positive (pre-test mean =3.85 on a 1-5 scale) and did not significantly (p = .20) increase as a result of the educational program (post-test mean = 3.94). Students were very positive toward both the lecture-discussion and engine demonstration components of the educational program; however, they were significantly (p < .0001) more positive toward the engine demonstration.

A Mobile Unit for Demonstrating Performance, Efficiency, and Emissions of Biofueled Engines

A mobile unit was constructed to demonstrate the relative power performance, fuel efficiency, and exhaust emissions of a compression-ignition engine fueled with biodiesel or petroleum diesel. A Kubota D902-E3B, Tier IV compliant, compression-ignition engine (3-cylinder, 16.1 kW @ 3200 rpm) was mounted on a modified 1.5 m x 2.4 m trailer. The engine is fueled from two auxiliary fuel tanks; manual valves are used to select the tank and fuel type. Digital platform scales are used to measure fuel consumption (on a mass basis). A computer-controlled water-brake dynamometer is used to load the engine and display engine rpm, torque, and power. Exhaust emissions (HC, CO, CO2, and NOX) are measured using a portable exhaust gas analyzer. Data can be imported into a spreadsheet template and the fuels can be compared on the variables of power, torque, specific fuel consumption (kg/kWh), thermal efficiency, and exhaust emissions. The portable unit has been used in educational programs for public school students, college students, farmers, Extension personnel, and industry representatives. Informal feedback and data from pre- and post-test assessments indicates that the mobile unit is an effective method of demonstrating the relative performance, efficiency, and exhaust emissions from compression-ignition engines fueled with biodiesel and petroleum diesel.

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

This study compared 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 B20>B100) and pto specific fuel consumption (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.

Fueling Kubota RTV900 Utility Vehicles with D2 and B20: Effects on Fuel Efficiency, Engine Wear, and NOx Emissions Written for presentation at the

This paper reports preliminary results from an on-going study that began in July 2007 comparing the fuel efficiency (h/L), engine wear, and NOx emissions (ppm) of nine Kubota RTV900 utility vehicles fueled with B20 and eight vehicles fueled with D2. The 3-cylinder, 16.1 kW utility vehicles are used by the Facilities Management grounds department at the University of Arkansas. The vehicles are primarily used for transporting workers and grounds keeping equipment. Data on fuel use and hours of engine operation for all 17 vehicles are collected through operator log books. NOx emissions are monitored at 3-month intervals using the AutoLogic AutoGas 6-gas emissions analyzer with a chemiluminescent sensor (0-5000 ppm with 1-ppm resolution). During the first nine months of the study, there was no significant (p>.05) difference in fuel efficiency between vehicles fueled with B20 (0.611 h/L) and vehicles fueled with D2 (0.629 h/L). There was no significant (p>.05) difference in corrected NOx emissions levels between vehicles fueled with B20 (293 ppm) and vehicles fueled with D2 (287 ppm). There was no significant (p>.05) difference in engine wear metals (ppm) between vehicles fueled with B20 and vehicles fueled with D2 when analyzed using an independent t-test. This 2-year study will provide useful, real-world data on the fuel efficiency and NOx emissions of compression-ignition utility vehicles fueled with B20.

A Compact Variable-Rate Sprayer for Teaching Precision Agriculture

A compact variable rate application (VRA) sprayer for use in teaching precision agriculture (PA) concepts and skills was developed and field tested. A 3.66-m boom-type field sprayer with a 227-L tank was used as the base unit. The sprayer was designed to be towed with an all-terrain vehicle (ATV) and was equipped with a 12 VDC electric diaphragm pump. Off-the-shelf Global Positioning System (GPS) and variable rate application (VRA) components were modified as necessary and installed on the base unit. For field testing, a 13.3-m wide by 97.5-m long test course was laid out and spraying prescriptions were written for field speeds of 2.74-km h and 5.47-km h. Forty replications at each speed were conducted over two days to evaluate position accuracy (actual on/off point versus prescribed on/off point). With a 2s delay programmed into the unit, the mean position accuracy was 0.30-m and 1.02-m at 2.74-kn h and 5.47-km h, respectively. Application accuracy tests revealed the capacity of the electric diaphragm pump was not sufficient to allow effective regulation of application rates due to flow sensor requirements. This limitation has little practical effect on the sprayer’s use as a teaching model, since the primary educational benefits center around the larger issues of understanding precision agriculture, collecting and managing spatial agronomic data, developing field and prescription maps, operating the equipment, and integrating multiple technology systems.