Patent ID: 8635989

Claim:
A method for operating an injection system for an internal combustion engine having a prefeed pump for conveying fuel out of a fuel tank and having a high pressure pump which is arranged downstream of the prefeed pump for conveying the fuel into a fuel accumulator, the method comprising: determining a prefeed value which is a function of at least one operating variable of the internal combustion engine as a function of a pilot control characteristic diagram, initializing a correction value for the prefeed pump with a safety value which is predefined in such a way that deviations from a predefined conveying behavior of the prefeed pump which lie within a predefined tolerance range are compensated for in such a way that a sufficient delivery performance of the prefeed pump is ensured, actuating the prefeed pump as a function of the prefeed value and the correction value, and adapting the correction value with regard to its effect to the conveying behavior of the prefeed pump as a function of a variable of the injection system, the value or value profile of which variable is representative for whether a desired pressure can be reached in the fuel accumulator, to be precise in the context of a reduction in the delivery performance of the prefeed pump as long as the value is representative for the fact that the desired pressure is reached in the fuel accumulator; the variable of the injection system, the value or value profile of which variable is representative for whether a desired pressure can be reached in the fuel accumulator, being a determined time-dependent profile of the pressure in the fuel accumulator, and the value being representative in this period for the fact that predefined deviations are not exceeded by a setpoint value of the pressure.