Emission characteristics of different combustion engines in the city, on rural roads and on highways

Abstract

For passenger cars the different emission rates for CO, HC, NOx and particles are described for operation in cities, on rural roads and on highways. Since there are great differences a distinction is made for the following combustion types: gasoline two-stroke and four-stroke engines without catalyst, gasoline engines with catalyst, with and without an oxygen sensor, diesel engines with and without an oxidation catalyst. The operation in cities is defined through different driving cycles, e.g. the European and US-City driving cycle and TÜV Rheinland urban cycles M3 and M4. The extra urban traffic is defined with intra- and extrapolation of another TÜV Rheinland cycle M2 with an average speed of 60 km/h and the constant speed of 100 km/h as well as the new European extra urban driving cycle. The emissions at 100 are multiplied by 30% to take into account the intermittent operation. As a result a ranking for each component is given. For CO two-stroke gasoline engines, four-stroke gasoline engines, gasoline engines with a catalyst without an oxygen sensor, gasoline engines in which the catalyst has an oxygen sensor, diesel engines and diesel engines with an oxidation catalyst. Two-stroke gasoline engines are by far the main HC-emitter. For HC and NOx the diesel engine is a little worse than catalyst equipped gasoline engines. Particles are mainly a problem for diesel engines but modern diesel have relatively low particle emission rates.