Effects of an Oxidation Catalytic Converter on Regulated and Unregulated Diesel Emissions
In this study, the effects of an oxidation catalytic converter (OCC) on regulated and unregulated emissions from a 1991 prototype Cummins I.10-310 diesel engine fueled with a 0.01 weight percent sulfur fuel were investigated. The OCC's effects were determined by measuring and comparing selected raw exhaust emissions with and without the platinum-based OCC installed in the exhaust system, with the engine operated at three steady-state modes. It was found that the OCC had no significant effect on oxides of nitrogen (NOX) and nitric oxide (NO) at any mode, but reduced hydrocarbon (HC) emmissions by 60 to 70 percent. The OCC reduced total particulate matter (TPM) levels by 27 to 54 percent, primarily resulting from 53 to 71 percent reductions of the soluble organic fraction (SOF). The OCC increased sulfate (SO42-) levels at two of the three modes (modes 9 and 10), but the overall SO42- contribution to TPM was less than 6 percent at all modes due to the low sulfur level of the fuel.