Bosch puts foot down on brake system of the future

Bosch has developed a brake-by-wire system for Mercedes-Benz which it claims improves a vehicle’s stability and reduces stopping distances. The Sensotronic Brake Control took seven years to develop, and is designed to replace conventional hydraulic brakes, saving on weight and space.

John Clack, Bosch commercial operations manager, said: ‘The technology is a further extension of many vehicles’ existing systems, such as ABS. But it has taken this long to develop because of the need to simulate pedal feel and travel duringnormal road use.’

SBC relies on a central computer, which monitors how the car is being driven and regulates the braking. It receives data on each wheel’s speed and position, which it combines with information from sensors that track the brake-pedal’s distance and rate of travel along its arc.

The pedal’s electronic unit replaces the bulkier vacuum booster and master hydraulic cylinder. But at present the law demands that manufacturers still build in a smaller, hydraulic braking system as a back-up.

Information from the braking unit is fed electronically back to each wheel’s pressure modulator. This is the only hydraulic part of the new system, and it applies pressure direct to the brake pads.

SBC has been fitted to the new Mercedes-Benz SL sports car. Both companies claim the system improves stability, for example when braking on a bend, and reduces stopping distances by three per cent at 75mph.

Bosch and Mercedes-Benz say they plan to combine SBC with adaptive cruise control as featured on the Mercedes S-Class and the BMW 7-series. Called Traffic Assist, this would enable vehicles to be brought to a stop while maintaining a safe distance from the car ahead, from speeds of up to 40mph.

Using radar to detect the car ahead, the data would be monitored with speed and wheel information. When the driver’s foot leaves the accelerator the brake is engaged, bringing the car to a steady standstill.

‘This is only the first stage in this system’s development,’ said Clack. ‘The technology will be taken further.’

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