Electronic Stability Program(ESP) first came into existence in the year 1987 when its earliest innovators Mercedes and BMW introduced Traction Control system. Traction control applies individual brakes and throttle while accelerating but it does not controls the steering like the ESP. Over the time, Mercedes developed it in collaboration with Robert Bosch GmbH or Bosch and named it Elektronisches Stabilitatsprogramm (German for Electronic Stability Program). On the other side, BMW too, in collaboration with Bosch and Continental Automotive System, developed a system to reduce torque and introduced it in its model lineup for 1992.
These little steps by these giants helped existence of ESP in modern motoring; and Mercedes Benz was among the first to introduce it in 1995, though it was supplied by Bosch.
Tech behind the working
ESP is always alive and its not just a system that kicks in critical conditions. Under normal driving conditions, it constantly monitors steering and moving direction, sitting in the background. It continuously compares the driver's intended path by the angle of steering and the direction vehicle is moving. The direction of vehicle is determined through the lateral acceleration, its rotation and wheel spin speed.
If in some case, it detects the clash between these two, that is the vehicle is not going where the driver wants it to, it kicks in prior to steering control loss. Then ESP asymmetrically brakes individual wheels of the vehicle to create a torque about the vertical axis of the car until it brings it back to the driver commanded path. It also reduces engine torque or transmission speed simultaneously to slow the vehicle down, if required.
Electronic Stability Control combines yaw (rotation about the vertical axis, spinning left or right of car) rate control into Anti Lock Braking System. ABS enables ESP to brake individual wheels. Moreover, many ESPs incorporate both Traction Control (TC) and ASR (Anti-Slip Regulation).
This system incorporates many sensors out of which some determine what the driver wants and the others decide where the vehicle is going. The control algorithm compares the driver input and vehicle response and operates accordingly if something unexpected happens. The ESP unit can also use other vehicle components like 4x4 drive and active suspensions to bring back the vehicle into control.
Causes of ESP to kick in
This loss or skidding could be the result of understeer, oversteer or evasive swerve due to some obstacle, like cattle or another vehicle. Vehicle could slip in heavy rain situation, gravel, sand and icy roads and it could be easily controlled by an ESP. Though in some reckless conditions like in hydroplaning or slippery roads, may cause the ESP to be ineffective but it could still reduce the damage. It also intervenes in case of high performance driving maneuvers, a one like drifting, and causes to restrict it totally. But in modern offerings, some ESP’s are made to do a certain amount of drifting or ESP could be shut down.
Is it costly?
Well, when it comes to human lives nothing is more expensive. In India it is not as popular as in developed countries. Also, safety features in India are treated as luxury features and hence, most of the people end up buying basic variants. Since, ESP works with ABS, it costs a little over ABS. In India, the accessibility of ESP is less as it is mostly offered in high end marques. The cheapest you can get is in Ford Ecosport 1.5 liter automatic variant.