ABS and Traction control systems

ABS AND TRACTION CONTROL SYSTEMS EXSPLAINED

In a modern world where more and more cars are being fitted with ABS and traction control it helps to understand why they are there, what they do and how do they work??

Starting with ABS -

ABS (Anti-locking brake system) is a system designed to prevent the wheel and tyre locking up and loosing friction, by locking up all four wheels on a car while braking the control of the vehicle is lost (steering) and stopping distances are massivly increase. ABS prevents this happening by releasing the brake to the wheel that is loosing grip when braking and then re-applying the brake again until the wheel starts to lock again.
To understand why ill tell you a little more about what the system consists off.

In an ABS system there are 4 metal reluctor rings placed normaly on the drive shafts and the rear hub, On each ring is a fixed inductive pik-up sensor that measures the speed that the wheel is spinning at, These sensor relay the information back to the ABS ecu where the information is interprited. Then there is an ABS mudule and pump which controls the rapid on - off motion of the brakes.
When you brake hard and one or more of the wheels start to loose traction and begin to lock up the sensors measure the rapid fall in wheel speed and in turn the ABS unit releases the brake to that wheel/wheels trying to lock until the wheel reaches the same speed as the road again and then it re-applys the brake once again.
By doing this the control of the car is maintained so the driver can steer away from an accident or round a corner while the brakes are firmly applied.

Traction Control systems -

There are differnt types of traction control which vary from one car manafacturer to another such as ESP,DSG,TC,ASC,ASR.
To look at a simple form of traction control being fitted to alot of cars now i will talk about ASC (Anti spin control).
ASR is designed to maintain traction when setting off fast or accelerating on wet surfaces etc on front wheel drive cars. The need for this is because while ever the wheels are not spinning the car can be fully controlled by the steering wheel, when the wheels start to spin say when your setting off sharpish from a roundabout with the wheels facing slightly one way and the wheels start to spin, acceleration is slow and the car can move around unsafly on the road, the car my very quickly slide into the next to you for example.
To prevent this happening the Anti Spin control uses the ABS system to apply brake to the wheel/wheels spining until they re-gain traction and then release the brake again. By doing this it means the car can pull away best as possible and safely with full control.
Anti Spin control can also kick in when you accelerate around a corner bescause cars without a Limited Slip Differnsial will spin the inside wheel as the weight is transfered so you loose the ability to actauly accelerate around the corner, by applying the brake to the wheel spining more torque is transfered to the wheel with lots of grip so your car will pull through the corner.

Systems such as ESP are the latest and more advanced versions of traction control, ESP or Electronic Stability Program are designed to give more fine control over the handling of your car when the car starts to loose control and you loose the ability to control a bad situation. Say for example you turn into a corner hard and accelerate and the car starts to understeer followed by oversteer leading to a violent swerve into a tree!!! the ESP would have seen a slight change in the front wheels as they speed up from loosing traction while understeering and it would back the throttle off stopping the torque to the wheel and then it would apply the brakes rapidly on and off from one wheel to the other to regain a stable motion, it would then have prevented the after affects of the manover. ESP is saving lifes and preventing accidents alot more than you would ever now if it is fitted to your car, only a flashing light on the dash shows the system is active.

feel free to ask questions or tell me your thoughts on these two systems.