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The knock behavior of two groups of unleaded gasolines, each of which includes three fuels with different chemical compositions but comparable standard octane numbers, has been analyzed using a mass-produced engine. The aim of the work was to point out possible inconsistencies between the standard octane numbers of the fuels and their knock behavior in mass-produced engines. The fuels of the first group had R.O.N.s and M.O.N.s very close to the minimum values required by European Community regulations (95 and 85, respectively), whereas the fuels of the second group had higher R.O.N.s and M.O.N.s (about 100 and 87.5, respectively). One of the tested fuels in the first group was a typical European unleaded gasoline, the other gasolines had higher olefin or aromatic contents. An increase of the aromatic content has not shown appreciable differences between the expected knock behavior of the fuel from its standard octane numbers, and its performance on the mass-produced engine.

During the last four years FIAT AUTO has cooperated with AVL in the development of three generations of ethanol vehicles for the Brasilian market for current, 1992 and 1997 Brasilian emission standards. This paper deals with suitability of ethanol as SI-engine fuel combustion system development and calibration strategies for 1992 lean burn engines and 1997 TWC-concepts transient and warm up development single fuel cold start systems TWC emission control requirements vehicle performance, fuel economy, emissions with and w/o catalyst. The paper shows that the concepts chosen allow calibrations with sufficient margin with respect to emission standards. Cold start and driveability can be developed for single fuel operation down to 0 deg. C. Vehicle driveability and performance are on a competitive level. For aldehyde control the TWC is a very good solution. Application problems with TWC can occur if the catalyst is located remote from the engine.