Function of the electro-pneumatic unit Signals are processed and errors monitored for the rear axles in the axle modulators, so that the sensor values can be subsequently transmitted to the central module via the data bus. The electro-pneumatic unit of the EBS system and its signal path work via Function of pneumatic redundancy Brake signal transmitter two distance sensors determine the nominal value which is transmitted as pulse-width modulated signal; two integrated switches are used for nominal value confirmation, among others Front and rear axle circuits work with different redundancy methods.
The front axle circuit works according to the additional redundancy principle, the rear axle circuit is equipped with a redundancy unit which can be activated with a valve.
EBS central module for determining the desired pressure for each axle, and system control Additional redundancy on the front axle Proportional relay valve for pressure control on the front axle The front axle circuit which functions pneumatically and serves as redundancy works via ABS solenoid valves for the quick ABS pressure control cycles on the left and right wheel brakes of the front axle Brake signal transmitter with 2 pneumatic circuits (front and rear axle) 3/2 relay valve for restraining the rear axle redundancy pressure Proportional relay valve relay valve with combined pre-control via pneumatic front axle circuit and the proportional solenoid valve Axle modulators with integrated control unit for regulating brake pressures on each side of the rear axle(s).
on the front axle brake cylinder. EBS can be activated electrically via the driving switch (pin 15) or by actuating the brake signal transmitter via the integrated brake switches. Electro-pneumatic pressure is delivered via the proportional valve when the brake signal transmitter is activated. Depending on the control force, pressure is supplied to the proportional valve by the brake signal transmitter in a delayed, pneumatically redundant manner. The measured brake pedal distance is interpreted as the desired delay and converted by the central module into desired pressure standards for the rear and front axle(s), using various criteria.
This is added to the pressure delivered already electro- pneumatically. The pressure delivered by the proportional valve is adjusted to the set desired pressure by varying the electro-pneumatic pressure. The nominal value standard for the axle modulators is transmitted by the central module via a central module. The axle modulators regulate and record the braking pressures of the rear axles’ left and right wheel brake. The braking pressure of the front axle is regulated by the central module via the proportional relay valve with integrated pressure sensor.
In case of electro-pneumatic unit failure, the pneumatic pressure part alone affects the proportional valve which can be raised to p max by actuating the brake pedal further. The wheel rotation speeds are recorded via the sensors known to the ABS system and serve, among others, as input quality for the pressure control algorithms, for the ABS function and for the ASR function.
Due to the need to restrain the front axle redundant brake pressure vis-а-vis the electro-pneumatic pressure output (for instance, measures to optimise wear, or integration of endurance brake), the ”electrical” nominal value predominates the pneumatic front axle pressure output on the brake signal transmitter (pneumatic dual circuit of the brake signal transmitter). Before carrying out a wear control operation, the brake lining wear sensors analyse the brake lining wear on each wheel brake. The sensor signals from the front axle are recorded by the central module whereas those from the rear axle are recorded by the axle modulators. Description of the EBS function 4. EBS 14