Report no. 99/51

21 Jan 1999

CONCAWE has reviewed the current gasoline volatility specifications within EN228relating to hot weather driveability, i.e. RVP, E70 and Vapour Lock Index (VLI), in anticipation of changes to volatility characteristics after year 2000, due to the impact of the new EU Fuels Directive (98/70/EC). This study utilises the assessment of the hot weather driveability (or Hot Fuel Handling (HFH) performance of current European vehicles and the trends of current and year 2000 car populations to determine the volatility requirements of individual European markets for year 2000. The generation and interpretation of such data is based upon extensive knowledge in this field accumulated by member companies over many years.Along with appropriate consideration of future trends in gasoline composition, the study leads to the conclusion that for year 2000 summer volatility classes, a VLI specification is no longer necessary. Data also shows that for other seasons volatility classes (non-summer time), a VLI specification is also generally no longer necessary. Only during the transition periods between summer and winter for four markets, identified as critical, might a VLI be used as an alternative solution to ensure satisfactory driveability.This report had been made available to CEN / TC19 / WG21 during their review of EN 228 and contains total customer satisfaction curves as a means of allowing the appropriate selection of volatility classes for individual European markets inaccordance with their climatic variation and car populations. Further proposals for changes to year 2000 volatility, in addition to VLI removal, are included in this report.Due to the proposed increase in minimum levels of E70 and E100, in addition to the introduction of an E150 minimum limit, the new version on EN 228 should improve the cold weather driveability performance of gasoline vehicles.