Jeffrey W. Hodgson

Stabilizing Excessive EGR With an Oxidation Catalyst on a Modern Diesel Engine

For diesel engines (CIDI) the excessive use of exhaust gas recirculation (EGR) can reduce in-cylinder oxides of nitrogen (NOx) generation dramatically, but engine operation can also approach zones with high instabilities, usually accompanied with high cycle-to-cycle variations and deteriorated emissions of total hydrocarbon (THC), carbon monoxide (CO), and soot. A new approach has been proposed and tested to eliminate the influences of recycled combustibles on such instabilities, by applying an oxidation catalyst in the high-pressure EGR loop of a turbocharged diesel engine. The testing was directed to identifying the thresholds of stable operation at high rates of EGR without causing cycle-to-cycle variations associated with untreated recycled combustibles. The elimination of recycled combustibles using the oxidation catalyst showed significant influences on stabilizing the cyclic variations, so that the EGR applicable limits are effectively extended. The attainability of low NOx emissions with the catalytically oxidized EGR is also evaluated.Copyright

Graduate Automotive Technology Education (GATE) Center

The Graduate Automotive Technology Education (GATE) Center at the University of Tennessee, Knoxville has completed its sixth year of operation. During this period the Center has involved thirteen GATE Fellows and ten GATE Research Assistants in preparing them to contribute to advanced automotive technologies in the centers focus area: hybrid drive trains and control systems. Eighteen GATE students have graduated, and three have completed their course work requirements. Nine faculty members from three departments in the College of Engineering have been involved in the GATE Center. In addition to the impact that the Center has had on the students and faculty involved, the presence of the center has led to the acquisition of resources that probably would not have been obtained if the GATE Center had not existed. Significant industry interaction such as internships, equipment donations, and support for GATE students has been realized. The value of the total resources brought to the university (including related research contracts) exceeds

Development of a Dedicated CNG Compact Car

4,000,000. Problem areas are discussed in the hope that future activities may benefit from the operation of the current program.

Fuel Nitrogen Conversion in a Spark Ignition Engine

The use of compressed natural gas (CNG) as a fuel for small vehicles presents challenges associated with the vehicle cost, system packaging, and vehicle range. The University of Tennessee with primary support from the Saturn Corporation has adapted a Saturn SL1 to dedicated CNG operation with the objective being to do so with a minimal impact on the production of the base vehicle. The adapted vehicle meets the California ULEV emission values at low mileage, achieves a gasoline equivalent fuel economy of 21 km per liter (49 miles per gallon) at a steady speed of 90 km/hr (55 miles per hour), and has a range (at 90 km/hr) of over 400 km (240 miles) when fueled with an initial tank fill of 24.8 MPa (3,600 psig). As expected, wide-open throttle performance of the adapted vehicle was degraded from the gasoline baseline vehicle. The vehicle design features are compared with two similar pre-production vehicles that have been described in the literature.

Development of Data-Based Light-Duty Modal Emissions and Fuel Consumption Models

Tests were conducted using an ASTM Aviation Supercharge CFR engine to determine whether high levels of fuel-bound nitrogen lead to increased nitric oxide emissions in a supercharge engine. Fuel nitrogen levels were formulated by doping several different fuels with pyridine. The results of the testing on this particular engine indicate that the effects of fuel nitrogen on nitric oxide emissions were so small that they were masked by the uncertainties associated with the experimental procedures used. Comparisons with the results from other researchers suggest that the results of this study are probably associated with stratification of the fuel-air mixture. It is recommended that additional tests be conducted to investigate the effects of fuel-air mixing on fuel nitrogen conversion. The purpose of this study was to determine how the nitrogen content of liquid fuels affects the nitric oxide emissions from a spark ignition engine. The study was motivated by concerns that future fuels may contain higher levels of nitrogen than the fuels they will replace - particularly if these future fuels are derived from coal or oil shales.