TRACTION CONTROL EXPLAINED

 TRACTION CONTROL

Traction system (How it works)

Overview:

Traction control is a dedicated electronic system that has the remarkable ability to reduce the chances of wheel-spin (slippage due to loss of traction)Traction Control System is activated when throttle input and engine power and torque transfer are mismatched to the road surface conditions. We've all had it happen to us - get a little too eager on the throttle on an imperfect surface and you’ll find your bike wanting to swap ends. So how do liter-class riders manage to whack open the gas without being sent into orbit? The answer is quite simple - traction control. The primary aim of any traction control system is to mitigate wheel spin under acceleration. To do this, you need to first know how quickly the wheels are spinning, and this is done using wheel speed sensors placed at either end of the motorcycle. The front wheel isn’t powered by the engine and is hence always rolling freely. In other words, unless you’re pulling a wheelie, your front wheel speed is equal to the overall vehicle speed. So when the rear wheel speed begins to exceed the front wheel speed, you know that there is some slippage occurring. This is what needs to be minimized. In essence, you need to reduce the torque being sent to the rear wheel, and there are a couple of ways to achieve this. The first, more rudimentary way, is by cutting ignition. With fuel not being ignited in the combustion chamber, no power or torque is produced for that cycle. So for example, cutting the ignition on every alternate cycle will result in a roughly 50% reduction in torque being sent to the rear wheel. In this manner, the exact amount of torque being sent to the rear wheel can be manipulated to ensure that front and rear wheel speeds always match up, and hence no slippage occurs. The second way to cut power to the rear wheel is by partially closing the butterfly valve in the throttle body. This restricts the amount of air-fuel charge entering the cylinder and consequently reduces the amount of power and torque produced by the engine. The smartest systems out there can even manipulate the butterfly valve opening independently on motorcycles with multiple cylinders and multiple throttle bodies to precisely deliver the exact amount of torque desired. In functioning, the wheel speed sensors send their data to the ECU, based on which it decides whether slippage is occurring or not. When slippage is detected, the ECU decides to either cut the ignition or partially close the throttle body/bodies depending on the hardware available, until both wheel speeds are equalized. Time and technology wait for none, and traction control systems are getting ever smarter by the day. The latest developments include IMU-assisted lean-sensitive traction control. The rear tire can put down more torque when the motorcycle is completely upright as compared to when it is leaned over. The IMU gathers data about the motorcycle’s orientation using its various accelerometers and gyroscopes and sends these numbers to the ECU. Based on this data, the ECU can further refine torque delivery to the rear wheel, minimizing wheelspin and maximizing acceleration.So the next time you roll on the gas with reckless abandon on a slippery surface and wonder how things panned out so smoothly, look down at the frantically flashing orange light on your cluster and appreciate the computer wizardry that’s keeping you right side up.

Operation

When the traction control computer (often incorporated into another control unit, such as the ABS module) detects one or more driven wheels spinning significantly faster than another, it invokes the ABS electronic control unit to apply brake friction to wheels spinning with lessened traction. Braking action on slipping wheel(s) will cause power transfer to wheel axle(s) with traction due to the mechanical action within the differential. All-wheel-drive (AWD) vehicles often have an electronically controlled coupling system in the transfer case or transaxle engaged (active part-time AWD), or locked-up tighter (in a true full-time setup driving all wheels with some power all the time) to supply non-slipping wheels with torque. Generally, the main hardware for traction control and ABS are mostly the same. In many vehicles, traction control is provided as an additional option for ABS. Each wheel is equipped with a sensor that senses changes in its speed due to loss of traction.

Traction control in cornering

Traction control is not just used for improving acceleration under slippery conditions. It can also help a driver to corner more safely. If too much throttle is applied during cornering, the driven wheels will lose traction and slide sideways. This occurs as understeer in front-wheel-drive vehicles and oversteer in rear-wheel-drive vehicles. Traction control can mitigate and possibly even correct understeer or oversteer from happening by limiting power to the overdriven wheel or wheels. However, it cannot increase the limits of frictional grip available and is used only to decrease the effect of driver error or compensate for a driver's inability to react quickly enough to wheel slip.

Conclusion:

Automobile manufacturers state in vehicle manuals that traction control systems should not encourage dangerous driving or encourage driving in conditions beyond the driver's control.