A closed-loop control device for closed-loop control of a power assembly is configured for: detecting a generator frequency of a generator; determining a control deviation as a difference between the detected generator frequency and a target generator frequency; determining a target torque as a manipulated variable for controlling an internal combustion engine as a function of the control deviation; using a control rule for determining the target torque; and adapting the control ruleused to determine the target torqueas a function of an adaptation variable, the adaptation variable being the detected generator frequency, a target torque variable, or a generator power, wherein the closed-loop control device can adapt the control rule by determining a proportional coefficient of the control rule such that a predetermined loop gain (v.sup.f) of an open control loop is constant, the predetermined loop gain (v.sup.f) being: v.sup.f=k.sub.p.sup.f((f.sub.G,stat)(30 M.sub.m,stat)).

Systems and methods for controlling fuel that is supplied to cylinders of an internal combustion engine are described. In one example, the fuel is controlled in response to output of two different outer-loop fuel controllers. The fuel may be controlled according to the individual separate outputs of outer-loop controllers or the combined outputs of the two different fuel controllers.