Abstract: Method and means are provided for effecting the controlled vaporization of a liquid fuel to simplify the ability to control a specific air-fuel ratio for an internal combustion engine. The invention contemplates two basic operations: first, a vaporized fuel is provided in which the fuel content is precisely known. This is accomplished by vaporizing liquid fuel with a diluent gas and separating out any fuel droplets so that the vaporized fuel is provided at the dew point. Second, orifice-venturi combination meters are incorporated in the inlet air and fuel flow paths providing respective air and fuel pressure signals which, when balanced against each other, establish a desired air-fuel ratio over a desired operating range of the internal combustion engine.