ASTM D2533 Test Method for Vapor-Liquid Ratio of Spark-Ignition Engine Fuels
4. Summary of Test Method
4.1 A measured volume of liquid fuel at 32 to 40°F (0 to 4°C) is introduced through a rubber septum into a glycerol or mercury filled buret. The charged buret is placed in a temperature-controlled water bath. The volume of vapor in equilibrium with liquid fuel is measured as the desired temperature or temperatures and the specified pressure, usually 760 mm Hg. The vapor-liquid ratio (V/L) is then calculated.
4.2 If it is desired to know the temperature corresponding to a given V/L, the vapor-liquid ratio is determined at several temperatures and the selected pressure. The results are plotted and the temperature read at the given V/L.
5. Significance and Use
5.1 The tendency of a fuel to vaporize in common automobile fuel systems is indicated by the vapor-liquid ratio of that fuel at conditions approximating those in critical parts of the fuel systems.
