The Impact of Oxygenates on Exhaust Emissions of Six European Cars

The effect of adding Oxygenates to the fuel, on exhaust emissions and fuel consumption, was evaluated. Chassis dynamometer tests (ECE + EUDC) were carried out on six petrol cars. Three of the cars were fitted with three way catalysts. The fuels had been oxygenated by adding 10 % MTBE, 15 % MTBE, and 5.2 % Ethanol. Test results show that oxygenates in the fuel reduce emissions and fuel consumption. Of the fuels investigated, addition of 15 % MTBE gave most benefits with the following reductions in emissions:- CO: 15 - 30 %, NOx: 1.3 - 1.7 %, THC: 10 - 20 %, CO₂: 1.0 - 4.0 %, Reductions in fuel consumption with 15 % MTBE were 1.3 - 1.7 % for non catalyst cars and 3.2 - 5.2 % for catalyst cars.