Traction Control is an Active Vehicle Safety Feature Designed to Safe Lives

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Traction control is an active vehicle safety feature designed to help vehicles make effective use of all the traction available on the road when accelerating on low-friction road surfaces. When a vehicle without traction control attempts to accelerate on a slippery surface like ice, snow, or loose gravel, the wheels are liable to slip. The result of wheel slip is that the tires spin quickly on the surface of the road without gaining any actual grip, so the vehicle does not accelerate. Traction control activates when it senses that the wheels may slip, helping drivers make the most of the traction that is available on the road surface.

A Computer-controlled safety system, keeps the car tracking right and getting the power to the ground through traction. Thus it didn’t take long for automotive engineers to work out that if you could control a car’s braking system to steer around objects, you could also optimise friction at the tyres for enhanced road holding and traction, in other words modern ABS and traction control systems are setup with the ECU and the hydraulic modulator attached together so that while they have different functions, they are physically one unit.

Friction or rather traction between your vehicle’s tyres and the road surface is the critical force that keeps the vehicle going where the driver intends it to travel. Without tyre grip the vehicle will travel in the direction of its momentum, causing the tyres to skid across the road surface. That of course applies in a lateral, sideways direction as well as in a straight line. Needless to say the condition of your vehicles tyres is crucial to how your vehicle behaves on the road. All other stability control systems (including the steering wheel) rely on this small contact patch each tyre maps out on the road surface for grip.

In 1990Bosch developed a electronic stability system and made its mainstream debut with Mercedes Benz and BMW. Known more generically within the industry as ESC (Electronic Stability Control), the system is now mandated in Australia as standard equipment for new passenger cars.

Though initially the ABS was introduced to prevent your wheels locking-up during braking (allowing vehicle manoeuvrability under braking). Additionally, sudden changes in vehicle attitude, due to evasive steering or road conditions, are controlled by the stability control system, today the system suppresses vehicle sideslip when driving due to vehicle spin (oversteer) or drift-out (understeer) by controlling braking and engine speed (torque). As a result, the driver can calmly react and is provided leeway for the next manoeuvre, resulting in safe driving conditions.  When brakes are applied to one side of the vehicle it is forced to pivot on an axis (theoretically the centre of the vehicle) and engine torque is reduced at the same time as the brakes are being applied to slow the vehicle and catch the oversteer/understeer condition.

Another function of the stability control system is traction control. Like stability control it is marketed under different acronyms, ETC, TCS or ASR, to list three. Traction control prevents the drive wheels from spinning on take off. If the drive wheels start to lose traction (start to spin) the traction control system reduces torque to the engine and brakes the drive wheels to prevent wheel spin, this happens many times per second which helps the drive wheels achieve grip. Think of it as ABS in reverse. And the beauty of traction control is that it can ‘nip’ a brake on just one drive wheel to deliver what’s known as ‘torque vectoring’ – the process of sending torque to the other drive wheel to level the vehicle’s cornering attitude, whether understeer or oversteering.

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