Abstract: A method and device for controlling the fuel and/or air supply to an internal combustion engine in the fuel section thereof, such as a carburetor or a fuel injection system, so that the mixture ratio (A/F ratio) is adjusted automatically to a desired level in response to various operational conditions. In a rotational-speed feed back regulating circuit, a feed-back control unit which receives information on the rotational speed from the engine briefly adjusts an adjustment device to provide a brief change of the mixture ratio and, in connection with the brief A/F/ ratio change, a number of revolution times are measured. At least one revolution time refers to a rotational speed that is essentially unaffected by the A/F ratio change and at least one revolution time refers to a rotational speed that is affected by the A/F ratio change. On the basis of these revolution times, at least one difference in revolution times between affected and unaffected rotational speeds is computed.

Abstract: A method and device for controlling the fuel and/or air supply to an internal combustion engine in the fuel section thereof, such as a carburetor or a fuel injection system, so that the mixture ratio (A/F ratio) is adjusted automatically to a desired level in response to various operational conditions. In a rotational-speed feed back regulating circuit, a feed-back control unit which receives information on the rotational speed from the engine briefly adjusts an adjustment device to provide a brief change of the mixture ratio and, in connection with the brief A/F/ratio change, a number of revolution times are measured. At least one revolution time refers to a rotational speed that is essentially unaffected by the A/F ratio change and at least one revolution time refers to a rotational speed that is affected by the A/F ratio change. On the basis of these revolution times, at least one difference in revolution times between affected and unaffected rotational speeds is computed.