So here we are back with the second part of our series- Safety Technology in Car. While last time we explained in detail about the ABS, this time we are explaining an extension of ABS, called ESP or Electronic Stability Control. Like ABS, ESP too is one of the most crucial components to prevent accidents and its importance can be judged by the fact that all the cars in U.S comes with a mandatory ESP.
Like we explained earlier, our aim of this series is to enhance the knowledge of our readers to understand safety, and hence, contribute in a very little manner we can. So, what is ESP, how does ESP works, and what are its components, we will address all your doubts.
What is ESP?
ESP refers to Electronic Stability Control or Electronic Stability Program and is almost a decade old now. Derived from the functionality of the ABS, ESP utilizes some advance sensors and controllers to avoid the car from getting into an accident, the ESP has been very successful, given the number of accidents it has avoided. The system was first developed by Bosch and the Mercedes-Benz S-Class and BMW 7-series were the first cars to use the new safety and regulatory devices.
What ESP does is use high-tech sensors, the car's central computer and mechanical actions to assist in driving safely by applying brakes on the individual wheels and reducing the power of the engine. What happens is, when a vehicle oversteers (a condition when the front wheels turn more than requires, causing the car to spin) or understeers (a condition when the front wheels don't turn as required), the ESP controls the situation, avoiding any mishappening.
How does ESP works?
The Electronic stability control system is not a single system, but a culmination of many safety systems in a car. The ESP takes help from the anti-lock braking system, traction control system and much more, and corrects problems before they become accidents. The basic component of the ESP is a 'Yaw Control Sensor'. What is Yaw? The name seems funny? Not at all! Infact, it is one of the three major aerodynamic force playing the role in a moving car.
There are three forces which come into action when a car is moving- Yaw, Pitch and Roll. The Yaw moment is along the Z-axis or the vertical of the car, and relates to the swinging motion. In simple language, any moment apart from the straight line motion, that is, left or right motion is Yaw. What a Yaw sensor does is, detects any out of the ordinary left or right movement of the car.
To detect any such movement, a Yaw control sensor is placed just underneath the driver's seat, in the centre of the car, somewhere between you and the passenger. As soon as the sensor detects something fishy, it uses all the modern electronic systems at its disposal, and activates individual brakes, depending on which wheel can increase driving safety the most. Also the engine power is controlled to reduce the speed. As explained earlier, the sensors look for the difference in the direction of the steering wheel and the direction the car is headed and then deploys corrective measures.
And how does it is different from an ABS? While an ABS controls the vehicle when it is in trouble, by applying manual brakes, ESP uses the ABS to detect the problem early and making it easy for the driver to control the car. We can say that the ABS is just a component of ESP.
The electronic stability control system consists of the ABS, Traction control system and many other sensors, to perform the job well. While we have explained the ABS in detail, in our previous article, the Traction control will be taken up in the upcoming series. We will explain the various sensors that are part of the ESP system for now.
ESC information is fed into the car's central computer via three types of sensor:
Wheel-speed sensors: One wheel-speed sensor at each wheel measures the speed of the wheel which the computer can then compare to the speed of the engine.
Steering-angle sensors: This sensor, in the steering column, measures the direction the driver intends to aim the car. If it's different than the direction the car is actually traveling, the ESC system will kick in.
Yaw sensor: This is also known as the rotational sensor. It's the one in the middle of the car that measures the side-to-side motion of the vehicle.
Benefits of Electronic Stability Control
There are innumerous benefits of the ESP system in a car, and we list down them point wise:
1. The most important role ESP plays is, reduce the severity of the crash, or in maximum cases, avoid the crash. If you are driving, accidents are bound to happen, if not by you, because of other's mistakes. Sometimes the roads are also responsible for the accident, like in the rainy conditions, ice patches or snowy roads. Electronic stability control, along with the other safety and regulatory devices on-board today's vehicles, can help drivers maintain control on the road.
2. ESP systems only come into action, when the conditions are too severe, that is the car is totally out of control. Sometimes, the is involved in a fender-bender, and a system like ESP can stop the car immediately, creating trouble for the vehicle following you.
3. ESP also has made the driving easier and less likely to end in a serious accident. According to various reports, ESP has prevented as much as 9,000 fatal crashes per year.