Abstract: In the method for the adapted precontrol and feedback control of the air/fuel mixtures to be supplied to the two fuel-metering devices of an internal combustion engine, which has two separate exhaust-gas channels with a lambda probe and a catalytic converter in each channel, a common value of the precontrol manipulated variable and a common lambda desired value are determined for both fuel-metering devices. On the other hand, values of a control manipulated variable are determined separately for each fuel-metering device and values of precontrol adaptation variables, which are dependent upon the values of the control manipulated value, are determined and are superposed separately one after the other on the common precontrol value. This method makes it possible to manage with a single device for both cylinder banks which are to be operated in a stereo lambda control.

Abstract: A method for operating a fuel-supply system using a lambda-control apparatus for an internal-combustion engine wherein the amount of fuel to be supplied to the internal combustion engine is a function of signals representing the speed (RPM), the engine load, the exhaust-composition, and the temperature of the exhaust-gas sensor together with the attainment of a given temperature of the engine as an additional control criteria for the lambda-control apparatus. The method further includes deriving a temperature signal from the internal combustion engine to operate a threshold element with a hystereses whose switching values lie at about 10.degree. C. and 50.degree. C. to 85.degree. C. for optimum fuel mixture in the combustion chamber. The output signal of the threshold element can be further utilized for a supplementary warm-up fuel enrichment for better ignition characteristics, engine smoothness, and exhaust gas composition.

Abstract: The exhaust system of the engine is provided with a reactor, for example a catalytic reactor; the air-fuel mixture normally fed to the engine is set to be on the lean range. During starting, the mixture is enriched for a predetermined time; the degree of enrichment is then decreased, in dependence on engine, or exhaust system temperature. After the engine, or the reactor has reached operating temperature, the composition of the mixture is controlled by operating parameters of the engine, or sensed exhaust gas composition.