Bosch reveals stability control for bikes

Motorcycles have been available with anti-lock braking and traction control systems for decades, but so far none have been fitted with the type of electronic stability control systems (ESC) that are now mandated for all passenger cars in Australia.

Bosch, the German automotive electronics giant that proved the life-saving potential of such yaw sensor-based systems in four-wheeled vehicles, has now developed motorcycle stability control (MSC), which it describes as “the first brake control system for motorcycles to ensure the best possible stability in all riding situations”.

The first series-production application of MSC, which is claimed to provide “optimum braking and accelerating even in bends” and “improved safety within the limits of driving dynamics”, will be for the 2014 model year KTM 1190 Adventure and Adventure R.

According to Bosch, MSC supports riders during both braking and accelerating, both in a straight line and while cornering – without any change to the motorcycle’s handling “and thus all the pleasure of riding”.

“Almost one in two fatal motorcycle accidents occurs in a bend,” said Bosch Chassis Systems Control division president Gerhard Steiger. “The Bosch MSC motorcycle stability control can help further reduce the number of accidents.”

Bosch says that in 2010 more than 5000 motorcyclists died in road accidents in Europe alone and studies show that ABS on its own can prevent around a quarter of all motorcycle accidents that lead to injury or death.

“The new stability control will increase this number even further,” said Bosch.

Head of the Bosch centre of competence for powered two-wheeler safety in Japan, Fevzi Yildirim, said MSC improves braking effectiveness and riding stability in all situations by using lean and pitch angle sensors.

“The technical basis of the MSC is the ABS enhanced system for motorcycles,” he said. “The new functions are made possible by an extensive array of sensors and sophisticated software.”

Bosch says MSC’s traction control function regulates maximum engine torque to maintain grip even on slippery road surfaces, but during heavy braking in corners it also reduces the motorcycle’s tendency to stand upright.

“In these situations, the eCBS electronic combined brake system creates the best possible distribution of brake force between the wheels, and thus stabilises the bike during cornering,” it claims.

MSC is also designed to reduce the risk of ‘lowside’ crashes, in which too much brake force is applied during cornering and the tyres lose traction.

“MSC counteracts this by detecting the risk of a lowsider and limiting the maximum brake force. The eCBS function distributes this maximum available brake force between the wheels, ensuring the best possible brake performance under cornering conditions,” says Bosch.

“The eCBS function ensures optimum distribution of brake force at all times – even when the biker mistakenly uses only one of the two brakes, or brakes with too much force.”

MSC also includes anti-wheelie and anti-stoppie control, with wheelie-mitigation controlling engine torque to prevent the front wheel from lifting uncontrollably and the rear-wheel lift-up mitigation function keeping the rear wheel on the road by reducing the maximum brake force on the front wheel on high-friction surfaces.

MSC employs a range of sensors to record the motorcycle’s handling dynamics in real time. Wheel sensors measure the rotational speed of both wheels, while an inertia sensor module computes the bik’s lean and pitch angles more than 100 times per second.

Bosch says that by analysing the sensor data including wheel speed differential, “the ABS control unit calculates the physical limits of brake force on the basis of lean angle.

“If the motorcycle stability control recognises that a wheel is starting to lock, the ABS control unit activates the pressure modulator in the hydraulic brake circuit. This lowers the brake pressure and builds it up again within a fraction of a second, with the result that exactly as much brake pressure is applied as is necessary to keep each wheel from locking.”

Bosch says MSC has the potential to save lives, but cautions it is not fool-proof.

“Bosch MSC can be a lifesaver. However, just like ABS, it cannot suspend the laws of physics. In particular, extreme misjudgement of the riding situation and major errors on the part of the biker can still lead to an accident.

“Nonetheless, the system supports bikers in borderline situations, helping them get more out of their motorcycles while keeping them much safer at the same time.”