The Effects of Oxygenates on Intermediate Temperature Drivability of 1983/1984 Cars

A test program has been completed to evaluate the performance of late model passenger cars using a variety of oxygenated fuel blends. The tests were conducted using the Coordinating Research Council (CRC) intermediate temperature drivability test procedure. The program involved the use of sixteen 1983 and 1984 model vehicles that were selected to represent a variety of engine sizes, fuel system types, emission system configurations, and auto manufacturers. Two trained drivers were used to test these cars with 15 different fuels. The fuels consisted of three volatility classes with each including a hydrocarbon-only gasoline and blends with methanol and ethanol at the 3.7 percent oxygen level. In blends involving methanol, gasoline-grade tertiary butyl alcohol (GTBA) was used as a cosolvent. Statistical analysis of the resulting test data showed that, as a group, the cars tested were insensitive to the addition of this level of oxygenates to the fuels. Also, as a group, the cars followed a trend in later model cars toward improved drivability performance.