Brake Force Control and Distribution in Passenger Cars, Today and in the Future

Today and in the future, a decisive importance is to be attached to the optimum brake force distribution. The increasing introduction of anti-locking controlled brake systems does not alter this fact. After a detailed dealing with the layout principles and the factors influencing them, the conventional brake force distribution, conditioned by the wheel brakes, as well as its dispersion due to friction coefficient variations, is described. A short survey of hydraulic pressure valves follows. After that, for the first time, the adaptive brake force distribution principle is described; the characteristics of this principle are by means of electronic control the brake pressure increase at the rear axle is controlled dependent of the actual tire-to-road adherence of at least one front or rear wheel. This type of brake force distribution controls the given relation of front axle and rear axle tie-to-road adhesion, irrespective of each given design parameter, the loading and driving conditions, as well as of other external or internal disturbances. A discussion of the control ranges of the anti-locking systems, depending on the actual brake force distribution, concludes the report.