Gasoline Volatility and Hot Weather Driveability of Japanese Cars

Hot weather driveability test procedures on a chassis dynamometer correlated with field tests were established, and the effect of gasoline volatility on driveability performance was examined using 11 Japanese cars.

It was found that the 50% evaporated temperature had a larger effect on hot weather driveability than the Reid vapor pressure. Also, hot idle compensators and fuel return systems were very effective for reducing malfunctions.

As to conditions which should be controlled in chassis dynamometer tests, wind velocity were important as the same as ambient temperature; however, sun loading was not.