Patent ID: 8333179

Claim:
A method of operating an internal combustion engine with an engine oil as a lubricant, wherein a fuel mass flow outgassing from the engine oil is calculated in a model and is taken into account via a map-based pilot control during a metering of a quantity of fuel supplied to the internal combustion engine, and wherein a fuel/air ratio supplied to the internal combustion engine is determined as a lambda control factor, the method comprising: selecting warm-up phases of the map-based pilot control; wherein the warm-up phases are based on evaporation properties; determining deviations of the lambda control factor from a nominal value during the relevant warm-up phases of the map-based pilot control; determining a mass flow offset from the determined deviations as a function of a size of the fuel mass flow outgassing from the engine oil and a fresh air mass flow drawn in by the internal combustion engine, wherein determining the mass flow offset comprises: taking into account a large share of the deviations of the lambda control factor from the nominal factor when the size of the fuel mass flow is large; and taking into account a small share of the deviations of the lambda control factor from the nominal factor when the size of the fuel mass flow is low.