Abstract: In the embodiment described in the specification, the fuel injection quantity for an internal combustion engine is adjusted for regulating smooth operation by recording a number of uneven operation fuel injection values for each individual cylinder during an observation interval, sorting the recorded uneven operation values individually for each cylinder operation according to their sign and magnitude, determining, individually for each cylinder, whether the median uneven operation value is lower than, equal to, or higher than zero, and increasing the injection quantity if the median uneven operation value is lower than zero, or reducing the fuel injection quantity if the median uneven operation value is higher than zero.

Abstract: An internal combustion engine has a temperature-dependent exhaust gas converter arranged to receive a secondary air supply from a secondary air pump, and the engine has a fuel vapor accumulator to collect fuel vapors from the fuel supply for the engine. During cold-starting of the engine, the air pump is operated to draw fuel vapors from the accumulator into the secondary air supply to regenerate the accumulator and provide a flammable secondary air-fuel mixture to the exhaust gas converter.