Abstract
Exhaust emissions were determined from a fleet of some 50 cars that have been in normal private ownership service in Finnish driving conditions. These represent typical Nordic climate with strongly varying ambient temperatures between summer and winter months. All cars were petrol-fuelled, and had an up-to-date emissions control system based on a three-way catalytic converter. Tested vehicles represented model years 1990 to 1996. They had odometer readings at the time of testing ranging from a low of 10,000 km up to a high of 373,000 km. The emissions performance was assessed using U.S. FTP75 urban driving schedule. Testing was carried out at normal ambient temperatures (+22 23 o C).
The paper reports an assessment of typical emissions performance as a function of distance driven encountered from normal TWC-cars that have been in day-to-day use under sometimes quite rigorous driving conditions. Additionally, for a subset of vehicles a follow-up and re-testing was performed after some two years rate also the stability of the subsequent emissions performance.
The results present information on the actual emission rates of typical in-service passenger cars. The results can be used e.g. in the emission inventory calculations or to rate the durability of the TWC emission control system under cold climate conditions.