EBS-BRAKING BY WIRE
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In a normal truck the braking process is activated by compressed air. With HS electronics the electrics perform this function-bytes and amperes, rather than bars are the maxim. Compressed air is still used as a medium for applying the brake at the wheel. Scania's EBS is based on allround disc brakes and a number of key components, including: + EBS control unit; + Service brake valve with pedal travel sensor; + Load sensor; + CAN data bus (CANController Area Network); + Trailer control valve; + One pressure-regulating module per wheel with a control unit for ABS/TC; + One lining-wear sensor per wheel; + One wire harness per wheel to the central control unit; + Wheel speed sensors at each
wheel.
The mechanical components include the sliding caliper disc brakes, the pneumatic components (for pressure generation and supply) and the mechanical park brake.
When the driver touches the pedal the service brake valve sends an electrical signal to the electronic control unit IECU). Pedal feel with EBS is said to be similar to a passenger car, with none of the slight vagueness of conventional pneumatic systems. The ECU also receives signals from the pressure regulating modules at each wheel and the load sensor. It processes this data and transmits braking pressure signals to the pressure regulating modules, as well as to the EBS circuit on the trailer, via the data bus.
The pressure regulating modules in turn give the command to pressurise the service brake cylinders with compressed air from the reservoir, thereby engaging the wheel brakes. Precise sensing of the actuating pressure also improves the ABS function. Brake applications are considerably faster with EBS than a conventional pneumatic system. The electronic control system also allows the brakes to be applied simultaneously on all wheels fitted with EBS providing more even, balanced braking across the complete vehicle/trailer combination.