OPERATING A COMBUSTION ENGINE BY MODELING AND REGULATING A FLUID ADMIXTURE IN A FUEL SYSTEM

In a method for operating an internal combustion engine with at least one cylinder (30), a predeterminable volume of a fluid is admixed to a fuel and the fluid-fuel mixture is introduced into a fuel system (50). A control device (60) considers the fuel system (50) as being subdivided, at least in sections, into a plurality of virtual segments (55, 56) with a predetermined volume, wherein the control device (60) detects a filling of the fuel system (50) with the fluid-fuel mixture as a successive filling of the segments (55, 56), stores a mixing ratio of the fluid-fuel mixture for each segment (55, 56), and controls the injection of the fluid-fuel mixture into the at least one cylinder (30) at least as a function of the stored mixing ratio.