Abstract: A method and a brake system for providing haptic information for a driver of a motor vehicle equipped with a brake-by-wire brake system concerning an operational state of the brake system. The brake system has a main brake cylinder which can be actuated by a brake pedal, having at least one pressure chamber associated with at least one wheel brake, and a simulation device which co-operates with the main brake cylinder and gives the driver a brake pedal sensation in a brake-by-wire operating mode. When a predetermined operational state occurs in the brake-by-wire operating mode, a brake pedal reaction, as a change to the stiffness of the brake pedal sensed by the driver is carried out by means of a disengaging valve which is connected to the pressure chamber of the main brake cylinder and by which the action of the simulation device can be switched on and off.

Abstract: A method and a brake system for providing haptic information for a driver of a motor vehicle equipped with a brake-by-wire brake system concerning an operational state of the brake system. The brake system has a main brake cylinder which can be actuated by a brake pedal, having at least one pressure chamber associated with at least one wheel brake, and a simulation device which co-operates with the main brake cylinder and gives the driver a brake pedal sensation in a brake-by-wire operating mode. When a predetermined operational state occurs in the brake-by-wire operating mode, a brake pedal reaction, as a change to the stiffness of the brake pedal sensed by the driver is carried out by means of a disengaging valve which is connected to the pressure chamber of the main brake cylinder and by which the action of the simulation device can be switched on and off.

Abstract: A device for determining a driving state of a two-axle motor vehicle, which driving state is formed from the driving situation of the motor vehicle and the state of the underlying surface, wherein output signals from vehicle on-board sensors are evaluated in order to determine the driving situation and wherein a routine for determining and/or estimating the friction value of the underlying surface is provided in order to determine the state of the underlying surface. Also disclosed is a method for operating a combined vehicle brake system, in particular for motor vehicles, having hydraulically actuable wheel brakes at a front axle and having electromechanically actuable wheel brakes at a rear axle, wherein the vehicle wheels assigned to the rear axle can be driven at least at times by an electric motor which can be operated as a generator for the recuperation of braking energy.

Abstract: A device for determining a driving state of a two-axle motor vehicle, which driving state is formed from the driving situation of the motor vehicle and the state of the underlying surface, wherein output signals from vehicle on-board sensors are evaluated in order to determine the driving situation and wherein a routine for determining and/or estimating the friction value of the underlying surface is provided in order to determine the state of the underlying surface.