Emissions Performance of Abatement Technologies Over the Proposed EEC Extra-Urban Driving Cycle

The definition of what is likely to be the new EEC extra-urban cycle has made it possible to determine the emission characteristics of cars fitted with different emissions control equipment. Central part of the evaluation programme were three versions of experimental lean and dilute burn engines in comparison with engine modifications and open and closed loop three-way catalyst systems.

It is concluded that both lean or dilute burn plus an oxidation catalyst and the closed loop threeway catalyst can lead to sizeable reduction of emissions. The former being clearly superior in CO-emissions, the latter holding this position in NOx-emissions.

It is speculated that the ultimate clean gasoline engine is to be composed of the two systems.