What are the key differences in the blending strategies for winter-grade versus summer-grade gasoline?

The key differences in blending strategies for winter-grade versus summer-grade gasoline primarily revolve around the Reid Vapor Pressure (RVP) and the inclusion of butane. RVP is a measure of the volatility of gasoline; it indicates how easily the gasoline evaporates. Winter-grade gasoline requires a higher RVP than summer-grade gasoline. This is because, in cold weather, gasoline needs to vaporize more readily to ensure easy engine starting and good cold-weather performance. The higher RVP allows the gasoline to form a sufficient vapor mixture in the engine's cylinders, even at low temperatures. Summer-grade gasoline, on the other hand, requires a lower RVP to prevent excessive evaporative emissions, which contribute to smog formation. High ....