Sunday 15 April 2012

Traction control - The technology which provides stability to your ride.

Almost all super bikes and cars nowadays are using a traction control system to maintain an excellent stability and also to provide better safety. I came across the word "Traction control" recently in a magazine. In that it was stated that all the race bikes which are being used in MotoGP races are equipped with a traction control system to assist better stability while cornering and sudden acceleration. Apart from that many top end cars also uses some kind of electronically controlled stability modules attached to it to maintain maximum stability and safety while if the driving situation goes out of control. In this part we'll see what a traction control means and how it works on your ride to provide stability.

In general, a traction control system is identical to some of the commonly and widely used electronic systems in vehicles today like ABS brakes, fuel injection systems and damping control system which uses micro controllers. It can be also called in many other names like ESC (Electronic Stability Control) ESP (Electronic Stability Program) VSA (Vehicle Stability Assist) etc depending on the brand of a vehicle.

Ducati 1098 assists traction control.
The super bikes and cars are usually equipped with high power engines which delivers instant power to the wheels to spin and move on. So when a situation like starting from halt to accelerate instantly and slowing down during cornering and accelerating again, there may a chance of wheel slip between the road surface and the vehicle. In bikes, the contact surface of tyres during cornering are not the same for both front and rear tyres. All these situations may lead to loss of stability & ultimately leading to an accident. 

In cars, during cornering or while taking a sharp turn the two rear wheels rotate at different speeds. This is being solved by using a differential on the drive axle. The traction control system in bikes senses the wheel slip when the drive wheel is breaking loose and spinning. This sensing is done by a traction control sensor which predicts the difference of wheel spins of front and rear wheel. After predicting the wheel slip, it sends a signal to the ECU (Engine Control Unit) and reduces engine power or applies brake to provide lost traction and making the bike to regain its stability.




Traction control in bike
You may occasionally experience a wheel spin when starting off or accelerating, particularly on a slippery or wet road surface. The Traction Control prevents wheel spin. While the Antilock Braking System ABS prevents the wheels from locking during braking by reducing the braking pressures, Traction Control ensures that the wheels do not spin when driving off or accelerating. To do this, the drive torque at each driven wheel is reduced respectively. Traction Control improves the traction of the vehicle and increases vehicle safety by avoiding unstable driving situations within the limits.


This feature is available in all super bikes like Yamaha YZF-R1, Ducati Diavel, 1098, Kawasaki ZX14-R etc..

Sensor box used in traction control system














Kawasaki Traction Control System

Powerful rear-drive cars from the sixties often had a primitive form of traction control called a limited slip rear differential. Sometimes referred to as Positraction, a limited-slip rear axle will mechanically transfer power to the rear wheel with the most traction, helping to reduce, but not eliminate wheel spin. While limited-slip rear axles are still in use in many front- and rear-drive vehicles today, the device can't completely eliminate wheel slip. Hence, a more sophisticated system was needed.


In cars ESC (Electronic Stability Control) is used which uses wheel speed sensors, steering wheel position sensors, yaw sensors to get the input value conditions. This system can apply brakes individually to any of the four wheels of the car to bring back its stability once the system detects if there is wheel slip or loss of stability. Manually we cannot apply brake to any of the four wheels in a car individually.

In some systems it also reduces the power output from the engine until the optimum traction between the tyre and road is obtained. In simple words its a reverse mechanism of ABS which senses wheel lock and in here the system senses for wheel spin.