Effects of MTBE on Gasoline Engine Cold Weather Operation

The cold weather performance of a gasoline containing MTBE was studied at -25°C in chassis dynamometer tests. The reference fuel was a hydrocarbon-only gasoline. Two passenger car engines were used to assess the effects of high MTBE content on cold weather operability. Tests with three MTBE concentrations (7, 16 and 25 vol %) were carried out at +20, -10 and -25°C.

In terms of driveability demerits, the performance of the gasoline containing MTBE was substantially similar to that of the reference fuel, MTBE improved the cold startability of the test vehicles. Fuel consumption rose along with the decrease in calorific value. The increase in MTBE content resulted in lower CO emissions from the test engines at all the temperatures studied. NOx and hydrocarbon emissions remained practically unchanged.

Our conclusion is that MTBE does not detract from a vehicle's cold driving performance. The main advantage of the use of MTBE is the fall in CO emissions.