Critical Factors Affecting Automotive Sulfate Emissions

Two recently completed experimental programs provide data on four critical factors affecting automotive sulfate emissions: catalyst selectivity, catalyst age, driving mode, and gasoline sulfur level. A fifth factor, excess 02 level is discussed, but was not studied experimentally. In the first program, 20 1975 California model cars each accumulated 80,000 km on fuel containing 300 ppm sulfur. The cars used three different catalyst systems and were tested under four different test conditions. In the second program, four catalyst systems were tested on fuels containing 24 to 469 ppm sulfur using SET, 64 km/h cruise, and FTP test conditions. /GMRL/