Search Results

A correlation between engine dynamometer- and vehicle-aged catalysts has been established for novel lean-burn applications. A lean-burn, 1.8-L Ford Mondeo with a close-coupled three-way catalyst and an underfloor lean-NOx trap was used for this study. Vehicle aging of the emissions control system was done using a prescribed driving schedule. Engine dynamometer aging was done using a four-event aging cycle modified for lean-burn applications. The two aging methods were compared using maximum NOx conversion efficiencies measured during a two-mode dynamometer evaluation cycle. It was found that 75 h of four-event dynamometer aging is equivalent to 80,500 km of prescribed vehicle driving.

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.