IPGATE E87 defines a new standard for a fail-safe brake-by-wire system, proposing a design with much higher braking performance in failure mode.

Pedal characteristics in Brake-by-Wire mode:

In brake-by-wire operation the pedal acts on a travel simulator, and the pedal force is determined by the non-linear spring characteristics of the travel simulator which generates a pedal force Fp. After 50% of the pedal travel, the travel simulator reaches its limit and just before the limit, the pedal force rises sharply. The relationship between pedal force and pedal travel is characterized by a first non-linear curve (58a). Furthermore, a second curve (58) is defined to assign a pressure to a given pedal displacement s or a pedal force Fp, i.e. the second curve (58) defines the pedal characteristics assigning a pressure to a pedal force Fp.

The relationship between brake pressure p and pedal force Fp is variable and can be adjusted to take account of factors such as vehicle deceleration or brake fading. This means that if the brake system is fading, a higher brake pressure can be applied for a given pedal force, ensuring consistent braking performance in changing conditions.

The short-stroke pedal simulator design allows full braking with a relatively short pedal stroke, resulting in a very responsive braking system.

Pedal characteristics in Failure Mode:

In the event of a failure, such as the loss of the electric motor generating the brake boost, the travel simulator is deactivated, resulting in increased pedal displacement and a different pedal force characteristic, i.e. to achieve a given pedal force Fp1, the pedal must be moved further along a third curve (59). The pressure is generated solely by the driver and the advantageous design with a small diameter of the master cylinder, about 40% smaller compared to conventional travel, allows a higher pressure to be generated for a given pedal force.

Unlike conventional brake boosters, such as vacuum or electric brake boosters, which are designed to meet UN/ECU requirements for a deceleration of 2.44 m/s2 at a pedal force of 500 N. The deceleration potential for a given pedal force is significantly increased, giving drivers less capable of applying a large brake force much greater confidence when driving. The new master cylinder design was setting a new standard for fail-operational brake-by-wire brake systems.

Brake system having an actuating device (30) and a control and regulating device (22), the control and regulating device (22) using the movement and/or position of the actuating device (30) controlling an electromotive drive device (5c, 6, 7, 7a ) controls, the electromotive drive device (5c, 6, 7, 7a) adjusting a piston (1) of a piston-cylinder system via a non-hydraulic gear device, so that in the working space (4, 4a, 4b) of the cylinder, a pressure being set, the working chamber (4, 4a, 4b) being connected to a wheel brake (15, 17) via a pressure line (13), and if the electromotive drive device (5c, 6, 7, 7a) the actuating device (30) adjusts the piston (1), characterized in that the pressure is regulated using a characteristic map, the control and regulating device (22) using at least one first sensor to determine the piston position and using a second sensor ors determines the current and sets the position of the piston (1) using the map, with the map being adapted during operation.