REPORTED here are the results to date of a study undertaken to determine the effects of ignition quality, viscosity, and volatility of fuels on engine performance, with particular reference to engine deposits, odor and lachrymation, low-temperature starting, power output, fuel consumption, exhaust cleanliness, and engine smoothness.
It is shown that cetane number appears to be of importance in engine starting, combustion roughness, misfiring, and varnish formation.
Less viscous and correspondingly higher volatility fuels gave better engine combustion, as evidenced by cleaner exhaust and less deposition in the engines tested.
For practical purposes, it appears further, that the API gravity of a fuel can be taken as a measure of its heating value, which, in this work, appeared to be the most important single property affecting power and economy.