ON-BOARD REAL-LIFE EMISSION MEASUREMENTS ON A 3 WAY CATALYST GASOLINECAR IN MOTOR WAY TRAFFIC, RURAL TRAFFIC AND CITY TRAFFIC AND ON 2 EURO-1 DIESEL CITY BUSES

On-board emission measurements were performed on a Ford Escort 1.3 l g asoline car and on two Van Hool A300D turbo diesel buses. When compare d to the limit values of the 91/441/EEC directive, the TWC car yields lower emissions in motor way traffic and values are about equal in rur al traffic. However, in the city with a hot start the CO- and HC + NOx -emissions amount to 5.7 and 2.3 g/km, that is double the limit values . Respectively, 16 and 4.2 g/km are measured with a cold start which i s five and four times the limit values. The Euro-1 diesel city buses, that are tested during the regular bus service, have on-the-road emiss ion intervals for CO, HC and NOx of respectively 7-8, 0.9-1.1 and 18-2 3 g/km. These transient emissions, transformed to g/kWh, are about 1, 0.5 and 1 to 1.5 times the Euro-1 limit values, respectively. The car to bus comparison of hot start city emissions in g/km shows that CO an d HC are about equal, whereas NOx is 30 times higher for the bus. Howe ver, in g/passenger km, CO and HC-emissions are respectively 30 and 50 times lower for the bus, while NOx-emission is equal.