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The continued pursuit in Europe for lower emissions from transport vehicles now identifies several new areas to be targeted as their total emissions become ever more significant when compared to the continued decrease in automotive emissions. One such transport area that now faces pressure in the reduction of exhaust emissions, is the scooter/ moped market. The new ECE R47 cycle that governs the operational mode of the vehicle specifies a typical driving cycle over which the total emissions are collected and analysed. This paper evaluates a carburetted 50 cc moped over such a cycle and from the results ascertains the possibility of catalysing the exhaust gas to achieve acceptable limits. An empirical catalyst model is used to predict exhaust gas and substrate bed temperatures with the view to prolonging durability of the catalyst support. Results are presented for operating strategies which offer better long-term durability.

The author believes the piston-ring problem to be an engineering one worthy of serious study and that it should be possible to standardize types and sizes in a way that will go far toward elminating present difficulties. It is stated that cast iron is the only satisfactory metal suitable for use in the internal-combustion engine and that the foundry offers the greatest opportunity for improvement, in the elimination of poor castings. The superiority of individually cast rings is averred and a formula for their composition is given. Leakage and oil-pumping are discussed, followed by comment upon the width and form most desirable for piston-rings; and some of the difficulties of their manufacture are enumerated, together with suggested improvements, inclusive of inspection and testing methods.