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Two catalyst formulations were tested on a diesel engine. A Fourier Transform Infrared (FTIR) analyzer was used to measure concentrations of nitric oxide (NO) and nitrogen dioxide (NO2). Other exhaust gas components were measured by conventional analyzers. The results indicate that nitrogen oxides (NOx) undergo complex chemical reactions in the diesel oxidation catalyst (DOC). The increase of NO2 occurring at a certain temperature range is accompanied by a decrease of the total NOx emission. NO2 is probably an important itermediate product in the lean NOx catalyst reaction chain.

The U.S. Bureau of Mines (USBM) and Diesel Controls Limited are evaluating a new diesel emission control system on an underground mine vehicle. The system is a catalyzed ceramic wall-flow diesel particulate filter (CDPF) combined with an oxidation catalytic converter (OCC). It is the first installation in the U.S. of a CDPF on a mining vehicle with a turbocharged engine at a high altitude mine, and the first installation of both a CDPF and an OCC on a mine vehicle. This paper describes the design and installation of the system on the load-haul-dump (LHD) vehicle. The results of screening tests conducted by the USBM are also given. The screening tests were conducted to determine if the device's particulate collection efficiency, regeneration temperature, and effect on gaseous hydrocarbon (HC) and carbon monoxide (CO) emissions changed over the period at was being used. The system was removed from the LHD and evaluated in the laboratory after operating for 308 and 1200 hours.