Two processes for metering fuel are disclosed. In one process, the expected intake manifold pressure during the next intake cycle is calculated and used to determine the quantity of fuel to be injected for the next intake cycle. In the other process, the quantity of air determined using the intake manifold pressure is corrected by means of a model which takes account of the effects of temperature. Both processes make it possible to meter fuel more accurately than conventional processes, which is an advantage particularly in the case of unsteady transitions. The ignition timing can also be advantageously adjusted using the calculated quantities of air.
