Method for performing open-loop/closed-loop control of the boosting of a braking force of a brake system, brake booster, and control unit

A method for performing control of boosting of a braking force of a brake system (1), wherein

• the brake system (1) comprises a brake booster (100) having a variable transmission (120) with an actuator (130) by which a variable additional force (F100) can be imparted to a piston (210) of a master brake cylinder (200) of the brake system (1),
• characterized in that,
• when a comparatively large additional force (F100) is requested a partial volume of a brake fluid is discharged from a brake circuit (300) of the brake system (1) so that a transmission ratio of the variable transmission (120) is adjusted and so that the piston (210) of the master brake cylinder (200) migrates into a new position, in such a way that the actuator (130) of the brake booster (100) is moved comparatively quickly into a first operating position in which it can impart a relatively large additional force (F100) onto the master brake cylinder (200), and
• in that the discharging of the partial volume of the brake fluid from the brake circuit (300) occurs by means of a controllable valve which discharges the partial volume into an equalizing circuit (400) or a low-pressure accumulator within an ABS or ESP system of the brake system (1), wherein the discharging of the partial volume takes place by means of an ABS or an ESP system of the motor vehicle, and the ABS or the ESP system discharges the partial volume at a rear wheel.