Effect of Fuel Volatility on Driveability at Low and intermediate Ambient Temperatures

The Coordinating Research Council (CRC) measured cold-start and warmup driveability at low (-20 to 28°F) and intermediate (40 to 69°F) ambient temperatures using sixteen 1980 model cars and nine fuels. This was the first CRC study at low temperature. Average driveability was worse at low than at intermediate temperature for some cars, but for others the reverse was true. As found previously, decreasing fuel volatility deteriorated driveability. A regression model was developed to relate cold start and warmup driveability to fuel volatility as measured by 10, 50, and 90% distillation temperatures. Overall, as ambient temperature decreased, the importance of the 10% distillation temperature increased.