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Recently Volvo Car Corporation introduced the new PremAir® catalyst system from Engelhard Corporation on their S80 luxury sedan and the new V70 estate wagon. In this paper, performance results of this catalyst system after long-term mileage accumulation will be presented. Urban taxi vehicles were used to test the catalyst over 110,000 miles. The rate of deactivation in long-term catalyst performance was found to be dependent on the radiator design, and was least for the radiator design with the highest total geometric surface area. Subsequently, a new catalyst version was developed in order to minimize the deactivation rate. This new catalyst has been evaluated under similar taxi driving conditions over 80,000 miles, and has shown improved durability performance.

This paper presents results from a quantitative characterization of the NO distribution in a SI engine fueled with a stoichiometric iso-octane/air mixture. Different engine operating conditions were investigated and accurate results on NO concentrations were obtained from essentially the whole cylinder for crank angle ranges from ignition to the mid expansion stroke. The technique used to measure the two-dimensional NO concentration distributions was laser induced fluorescence utilizing a KrF excimer laser to excite the NO A-X (0,2) bandhead. Results were achieved with high temporal and spatial resolution. The accuracy of the measurements was estimated to be 30% for absolute concentration values and 20% for relative values. Images of NO distributions could also be used to evaluate the flame development. Both the mean and the variance of a combustion progress variable could be deduced.