CONCAWE/GFC Study on Gasoline Volatility and Ethanol Effects on Hot and Cold Weather Driveability of Modern European Vehicles

A joint test programme has been carried out by CONCAWE and GFC to evaluate the impact of gasoline volatility and ethanol on the driveability performance of modern European vehicles. Eight vehicles, three with DISI fuel systems and five with MPI, were tested for hot driveability performance. After screening tests, a subset of four vehicles was selected and tested for cold driveability. The latest test procedures developed by GFC were used for both hot (20, 30 and 40°C) and cold (+5 and -10°C: representative of moderate winter conditions) weather testing on climate controlled chassis dynamometers. A matrix of four hydrocarbon test fuels at two levels of DVPE and E70 was blended for the hot weather testing, and three fuels with varying E100 but essentially parallel distillation curves for the cold weather tests. For each hydrocarbon fuel, two other fuels containing 10% ethanol were made, one splash blend and one with matched volatility. Some tests were also carried out using 5% ethanol fuels made by blending hydrocarbon and 10% ethanol fuels. The paper describes the detailed results obtained for both hot and cold weather driveability, in terms of vehicle, fuel (volatility and ethanol content) and temperature effects.