Abstract: A method for operating an closed-loop control system for injecting fuel into an internal combustion engine, with the control system having an error correcting capability for deviations that occur in the control signal being processed by the control system, and with the control system having a controlling element, which is embodied as a precontrol, PI-controller that are operated in parallel, and a non-volatile memory for storing deviation signals.

Abstract: A method and apparatus for determining the injected fuel quantity in internal combustion engines having self-ignition are proposed. A performance graph is prepared which includes the injected fuel quantity per stroke in accordance with the injection duration, with the rpm as a parameter. In order to avoid a fictive 0 point, the injection duration is shortened by a predetermined period of time and multiplicatively linked with an rpm signal, while linear rpm correction curves having a dependency of the rpm voltage on the injection duration can be assumed. At the output of an integrator by means of a sample and hold circuit, an injection quantity signal is produced whenever the rpm signal (Un) is supplied to the integrator for the integration process and the duration of the integration is determined on the basis of the injection duration signal (SD).