OREANDA-NEWS. November 12, 2012. Two-wheelers dominate traffic in Asia's cities. Without the crumple zone of a car, however, the risk of injury for riders in an accident is much higher. Bosch has developed an antilock braking system which is specially adapted to the low-cost motorcycles and scooters common there. It is based on the Generation 9 braking control system for motorcycles, but it has only one hydraulic brake channel, which controls the front wheel. “The new front ABS offers a great improvement in safety at a low cost,” says Gerhard Steiger, president of the Chassis Systems Control division. “ABS can reduce the number of accidents with injuries and fatalities by a quarter.” Known as the ABS 9M light, this system is currently under development in the Bosch center for motorcycle safety in Japan, in cooperation with an Indian motorcycle manufacturer. Series production will start in 2013.

 When a wheel on a motorcycle locks up, this invariably results in a critical situation. And where a locked rear wheel can often be unlocked by releasing the brake, such a reaction nearly always comes too late in the event of a locked front wheel, and it is practically inevitable that the rider will take a spill. Weight shifts forward during braking, and so deceleration takes place primarily through the front wheel. This explains why in many Asian countries, even the rear wheels of motorcycles with engine displacements of 250 ccm and above are braked by a mechanical cable brake. “Regulating braking pressure at the hydraulically braked front wheel prevents locking and achieves maximum deceleration, and so greatly increases stability,” says Dr. Wolfgang Hiller, regional president of the Bosch Chassis Systems Control division in Japan.

High-performance ABS generation forms the basis
The new ABS 9M light is a cost-effective entry-level version of the Bosch Generation 9 braking control system for motorcycles. The hydraulic unit comprises two control valves, a storage chamber, and a pump element. As is the case with more powerful ABS systems, the electric motor that drives the return pump is mounted here, as is the control unit – in this case a circuit board. The wheel-specific reference velocity is calculated by the system on the basis of speed information relayed by a sensor in the front wheel. For the highest possible stability during braking, the wheel-specific reference velocity is continuously adapted to the actual vehicle speed. More precise braking control is possible if a second sensor is installed on the rear wheel. With this setup, deceleration rates match those of the basic 2-channel system, and counteract any lifting of the rear wheel. Motorcycle manufacturers can optionally integrate an on-off switch.

 The software for the new front ABS has been optimized for the lower power segment. For larger, more powerful motorcycles, Bosch offers the ABS base and ABS plus systems, which control both wheels and offer additional optional functions. At the top of the range, there is the ABS enhanced system. Its integrated eCBS composite brake function always brakes both wheels, even when the driver only applies one of the brakes.