Method for operating an electrically actuable feed pump in a hydraulic circuit

A method for operating an electrically actuable feed pump comprising:

• an electric motor in a hydraulic circuit, which draws in a normal supply of fluid from a fluid sump, wherein the fluid circulated in the hydraulic circuit can be fed back into the fluid sump,
• wherein air intake occurs at least partially during a fluid undersupply condition,
• wherein the electric motor is integrated with a control circuit, which is provided with a control unit, which actuates the electric motor on the basis of an actual rotational speed and of a target rotational speed,
• wherein the control unit is associated with an evaluation unit for detection of the fluid undersupply condition, which is provided with a filling state model unit,
• wherein the evaluation unit compares the actual rotational speed of the electric motor to a reference rotational speed at an equivalent current consumption in order to detect the fluid undersupply condition, wherein the equivalent current consumption is correlated with the reference rotational speed,
• wherein the filling state model unit maintains a predictive model which generates a predicted fluid level of the fluid sump based on input data, the input data of the predictive model comprising a time variable and an occurrence of at least one event which exerts influence on an actual fluid level of the fluid sump, and
• wherein an evaluation of the feed pump for detection of the fluid undersupply condition is carried out only upon the fulfillment of a test condition in which the predictive model predicts a predicted fluid level of the fluid sump that is above a specified level.