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Alcohols (methanol and ethanol) have been identified as having the potential to improve air quality when used to replace conventional gasoline. This potential is primarily due to the different organic species that are emitted by alcohol-fueled engines. The use of “near neat” alcohols gives greater benefits than fuels containing lower levels of alcohol, but neat alcohols present a significant cold starting problem. The primary objective of this study was to develop a rich combustor device which will extend the cold start range of alcohol fueled engines to -30° C. In this approach a portion of the fuel is burned outside the engine under fuel-rich conditions. This rich combustion creates a product stream that contains significant amounts of hydrogen and carbon monoxide (along with other gases such as carbon dioxide, nitrogen, water vapor, and organics). The hydrogen and carbon monoxide are combustible and non-condensable and provide the fuel for starting the 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 (3600 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.

Due to increasing interest in the emissions-producing characteristics of today's automobiles, emissions testing procedures have come under close scrutiny. In addition, development of procedures to measure emissions of vehicles operating in “on-road” conditions have been proposed to gain knowledge of the instantaneous mass flow rates of various legislated gaseous emissions. The problem with the measurement of these instantaneous flow rates is that the responses of modern emissions analyzers to transients are too slow for reliable results. Therefore, a method for improving the dynamic response of these instruments is needed. A method is described which utilizes generalized predictive control theory concepts in conjunction with system identification techniques to produce a software “filter” which reconstructs the distorted output of these analyzers.