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Motorcycle sales have increased consistently during the last decade mostly in developing countries, especially in the BRICS. Low cost and less fuel consumption comparing to cars associated to the economic growth are the main reason for such trend. Emission limits have become stricter and the use of gas after treatment devices is widely present in new models. Flex fuel motorcycles have now become available, but effects of the combination of diverse gasoline/ethanol blends on the emissions are still an open issue that requires further understanding. This paper presents the most recent results regarding regulated and unregulated emissions from a Flex Fuel motorcycle fuelled with 4 different gasoline/ethanol blends: E22, E61, E85 and 100% ethanol. Both regulated (CO, THC, NOx) and unregulated emissions (Aldehydes, NMHC, NH3, N2O) were studied.

In order to comply with the introduction of new emission limits, motorcycles have been equipped with electronic injection systems and three-way catalytic converters for emissions abatement. However, these converters produce unwanted reactions, such as the formation of ammonia. This paper was focused on ammonia emission reduction in motorcycles. To provide ammonia abatement, one SCR (Selective Catalytic Reduction) catalyst has been developed and installed in a fourstroke motorcycle in addition to the original one, a three way catalyst (TWC). SCR systems work by chemically reducing NOx (NO and NO2) to nitrogen (N2). This is an experimental research work conducted by the Research and Development Institute (Lactec) and the Umicore Automotive Catalysts. Regulated and unregulated emissions have been measured in a chassis dynamometer test cell.