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From 1995 to 1997, the Coordinating Research Council (CRC) conducted a cold-start driveability program to evaluate the behavior of lower volatility fuels at cold, intermediate, and warm ambient temperatures. The program used 135 vehicles to evaluate 87 hydrocarbon, MTBE blended, and ethanol blended fuels. Evaporative driveability index equations (EDIs) were developed using the test design fuel variables (E158°F, E200°F, E300°F), and three other variable sets: (E158°F, E250°F, E330°F), (T10, T50, T90), and (E70°C, E100°C, E140°C). The models that best fit the data contained oxygenate offsets. Overall, the best indices are the E70°C, E100°C, E140°C equation and the DI equation with offsets.

In response to industry demands for a method to qualify fuels for their intake valve deposit (IVD) forming tendencies, the Coordinating Research Council (CRC) has developed an engine dynamometer test procedure. In Phase I, the 2.3L Ford engine was chosen as the focus test engine in comparison testing with two other high volume U.S. manufactured engines.1* A two-mode dynamometer test was developed in Phases II-A & II-B and shown to discriminate among the test fuels at a 95% confidence level.2 In Phase III, both an interlaboratory study (ILS) of the two-mode dynamometer test and a vehicle fleet study were performed. The ILS was conducted to determine the repeatability and reproducibility of the test procedure and also to fulfill requirements for consideration of the test as an American Society for Testing and Materials (ASTM) standard.