An experimental and theoretical study of automotive catalytic converters for ethanol-fuelled engines

• Main Author: McAtee, Claire Roberta
• Published: Queen's University Belfast 2013
• Subjects: 629.2528
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.602397

The aim of this work was, to investigate and model the performance and characteristics of automotive catalytic converter formulations when subjected to a synthetic exhaust gas mixture representative of that emitted by an ethanol-fuelled engine. A synthetic gas reactor and exhaust gas analysers were used to investigate the catalytic activity and chemical mechanisms exhibited by various catalytic converter formulations. Commercially available automotive after•treatment modelling software was used to simulate the behaviour of one specific formulation. The experimental work contained within this study includes investigations into the procedures of initial thermal stabilisation and periodic pre•treatment of catalytic converter test samples. Protocols were established for stabilisation and pre•treatment and were adhered to in the subsequent experimental work. Further experimental work investigated the performance of platinum, palladium and palladium/rhodium catalytic converter formulations when subjected to non•traditional exhaust gas compounds as found from ethanol fuel combustion. In addition to catalytic activity these tests also revealed the chemical reaction pathways associated with each formulation. The final phase of testing was carried out using a 'Super Ultra Low Emissions Vehicle' specification catalytic converter sample provided by Jaguar Land Rover. This sample comprised of palladium and rhodium and was tested for catalytic performance and its chemical reaction pathway characteristics were found to be consistent with that of the original palladium and rhodium formulation tested. Further data was extracted from this sample with respect to the promoting and inhibiting compounds required for the purpose of structuring kinetic rate equations pertaining to the ethanol exhaust gas species chemical reaction pathways. These kinetic equations were required for modelling the formulation. A commercially available after•treatment modelling platform named Axisuite was used to simulate the performance of the 'Super Ultra Low Emissions Vehicle' sample. This software was used to assign the pre• exponential frequency factor and activation energy variables with in the reaction rate equations. A set of global kinetic coefficients was established.