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The exhaust gas mixture of a carburettored 2-stroke engine requires specially designed catalyst formulations if optimum pollutant conversions, durability and cost requirements are to be realised. Formulation improvements which increase the conversion of carbon monoxide (CO) allow manufacturers to tune their vehicles richer to give more power, improve rideability and promote longer engine life. In order to design catalyst formulations which facilitate engine tuning whilst still meeting legislative emissions targets, a study was performed on the effects of platinum group metal (PGM) combinations and advanced washcoat materials on CO performance. The effect of PGM and washcoat materials on fresh and aged CO conversion were assessed on vehicles representative of the European, Chinese and Indian markets. A road-correlated bench engine ageing cycle was used to simulate 30,000 km road ageing.

In many parts of the world, two and three-wheelers are the principle mode of transport for the majority of people. The large numbers of these vehicles contribute significantly to urban pollution, and many of the affected countries are introducing legislation to reduce emissions from these sources. This paper reviews the current emissions legislation in Europe, India and China, and describes the aftertreatment systems that have been designed to give emissions which comply with the legislation on both 2-stroke and 4-stroke powered two-wheeled vehicles.

Ceramic honeycombs have been used as automotive catalytic supports in Europe. USA, Japan and other highly urbanized countries. (1)(2)(3) Maximising engine power output is of great interest to automotive manufacturers. Power output is partly dependant on the back pressure of the catalytic converter in the exhaust system. This paper discusses the use of a catalytic converter, designed to give a low pressure drop, that incorporates a ceramic catalytic support with low cell wall thickness. Further discussion concerns the canning techniques associated with this new substrate material, as well as converter durability and engine performance.