Design, Development and Analysis of Mullite Catalytic Converter for CI Engines

Emissions of Hydrocarbon (HC), Carbon Monoxide (CO) and Oxides of Nitrogen (NOx) are the largest concerns for fossil fuel driven automotive vehicles. Catalytic converter is an important component in the selective catalytic reduction process. It oxidizes harmful CO and HC emission to CO₂ and H₂O in the exhaust system and thus the emission is controlled. Different kinds of problems are associated with noble metal based catalytic converter. A catalytic converter with a new catalyst for compression ignition engine is considered in this study. The catalytic converter is designed and developed with a new catalyst. Due to better durable characteristics and poison resistant nature, non-noble metal based material limestone (mullite) is selected as a catalyst for catalytic convertor and the emission characteristics are studied on four stroke single cylinder CI engine by using mullite based catalytic converter. The results are compared without catalytic converter in the same engine. In the design stage, the back pressure analysis is performed on perforated mullite plate with ANSYS software. After arriving satisfactory results, the design is taken for development. The developed catalytic converter is tested on a single cylinder DI diesel engine coupled with dynamometer under variable engine running conditions. Though not a noble metal, limestone works as a catalyst for reduction of HC, CO and NOx emissions. It is therefore concluded that a simple low-cost limestone based catalytic converter can be thought as an alternative for expensive noble metal based converters.