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The aim of this paper is to analyze the quantitative impact of fuel sulfur content on particulate oxidation catalyst (POC) functionality, focusing on soot emission reduction and the ability to regenerate. Studies were conducted on fuels containing three different levels of sulfur, covering the range of 6 to 340 parts per million, for a light-duty application. The data presented in this paper provide further insights into the specific issues associated with usage of a POC with fuels of higher sulfur content. A 48-hour loading phase was performed for each fuel, during which filter smoke number, temperature and back-pressure were all observed to vary depending on the fuel sulfur level. The Fuel Sulfur Content (FSC) affected also soot particle size distributions (particle number and size) so that with FSC 6 ppm the soot particle concentration was lower than with FSC 65 and 340, both upstream and downstream of the POC.

This paper presents a study of passenger cars in terms of emissions measurements in tests conducted under real driving conditions (RDE - Real Driving Emissions) by means of PEMS (Portable Emission Measurement System) equipment. A special feature of the RDE tests presented in this paper is that they were performed under Polish conditions and the specified parameters may differ from those in most other European Union countries. Emission correction coefficients have been defined, based on the test results, equal to the increase (or decrease) of driving emissions during the laboratory (‘chassis dyno’) test or during normal usage in relation to the EU emission standards (emission class) of the vehicle.

Cold starts are demanding events for spark-ignition (SI) internal combustion engines. When the temperatures of the engine oil, coolant and the engine block are close to the ambient temperature, start-up can be difficult to achieve without fuel enrichment, which results in significant excesses in exhaust emissions and fuel consumption. In general, the lower the ambient temperature, the more substantial these problems are. Many nations frequently experience sub-zero ambient temperatures, and the European Union (among others) has specified an emissions test at low ambient temperature (-7°C). Passenger cars typically experience one to two cold start events per day, and so both cold starts and the warm-up period that follows are significant in terms of exhaust emissions. This paper examines emissions at low ambient temperatures with a special focus on cold start; emissions are also compared to start-up at a higher ambient temperature (24°C).