The test programme was carried out in order to establish the influence of type and concentration of commercial oxygenates in motor gasoline on the exhaust emissions of European cars.
All the tests were done on a chassis dynamometer combined with a CVS-test-system according to EC-Specifications. Moreover, all the measurings were taken on the European driving cycle ECE R 15.04 with additional measuring at constant speeds.
A test fuel series was blended to cover the full range of oxygenate compositions in accordance with the EC Oxygenates Directive in addition, some blends were used which exceeded these limits. The fuel series included fuels containing 3 V% methanol + 2 V% cosolvent, 5 V% methanol + 3 V% cosolvent, and up to 20 V% MTBE. In addition to these fuels other gasolines without oxygenates were blended and included in the exhaust emission tests.
The test fleet consisted of carburetor, injection, catalyst and non-catalyst equipped cars, all designed to run on unleaded motor gasolines.
The results of measuring the limited exhaust gas emissions are described and related to the fuel-matrix as well as to the different engine designs.