Design, Modification and Testing of a Catalytic Converter for Natural Gas Fueled Engines

A new catalytic converter (catco) for use in natural gas fueled engines is reported. The catco contains a wire mesh substrate and is based on titanium dioxide (TiO2) and cobalt oxide (CoO). Such materials are preferable to the use of the conventional noble metals palladium and platinum. Environmental emissions of platinum group metals from conventional catcos, jewelry manufacturing and medical usage have been identified as posing a risk to human health risk. The TiO2/CoO wire mesh catco and compressed natural gas (CNG) direct injection (DI) engine were developed under a research collaboration. The original engine manufacturer (OEM) catco was based on noble metal catalysts with a honeycomb ceramic substrate, and was also tested for comparison purposes. Conversion efficiencies of the TiO2/CoO wire mesh catco were found to be 93, 89 and 82% for NOx, CO and HC emissions, respectively. The TiO2/CoO wire mesh catco results in 24, 41 and 40% higher reductions in NOx, CO and HC emissions, respectively, in comparison to the OEM catco. This study aimed to develop a low cost three way catco for use with the newly developed CNG-DI engine. Details of its development and testing results are discussed.

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