Hot-weather driveability performance is influenced by vehicle design, ambient temperature and fuel volatility. For individual markets, the gasoline producer can control this aspect of performance by adjusting the fuel volatility level to meet the requirements of the car population under the seasonal ambient temperature conditions.
The volatility expression that has been successfully used for several years to control hot-weather iriveability is (RVP + 0.7E70).
A standard CBC test procedure is used by a volatility data-sharing group of European oil companies to characterise the performance of modern car models available in European markets. The data thus produced are used to determine the hot-weather driveability performance of European car populations.
The data reveal that the performance of these car populations has improved significantly over recent years, although some modern car models with high under-bonnet temperatures show some deterioration. Using this approach to setting gasoline volatility levels, very high levels of consumer satisfaction have been achieved.