How Does the Electronic Stability Program (ESP) Work?

What is Electronic Stability Program or Electronic Stability Control (ESP/ESC)?

Imagine you are driving a car at high-speed and suddenly come across an obstacle. In such a scenario, you will be forced to take a sharp turn or apply brakes to avoid a possible collision. While doing so, you might lose control and skid off the road. Thus, it may lead to an untoward incident such as an accident. Also, the car you are driving may tip over. So, to avoid this situation, the manufacturers employ Electronic Stability Program or Electronic Stability Control system. It is one of the active safety systems in a modern car.

The term ESP stands for Electronic Stability Program while the ESC for Electronic Stability Control. It is an intelligent safety system which can predict driving intentions. Firstly, the ESP helps the driver to maintain the wheel trajectory. It does so by applying brakes to the individual wheels. Secondly, it can also adjust the engine performance in critical maneuvers. However, the ultimate purpose of the ESP is to enhance vehicle stability. Thus, ESP improves stability by avoiding skidding.

Components of the Electronic Stability Program or Electronic Stability Control:

The Electronic Stability Program consists of the following components which are:

1. Hydraulic Unit
2. Wheel speed sensors
3. Steering angle sensor
4. Yaw rate and lateral acceleration sensor
5. Engine Control Unit

Components of Electronic Stability Program, Electronic Stability Control

How does the Electronic Stability Program or Electronic Stability Control work?

The wheel speed sensors detect the speed of each wheel. Furthermore, they send this data to ECU continuously. The steering angle sensor determines the position of the steering wheel by measuring the actual steering angle. Additionally, the Yaw rate and lateral acceleration sensors determine the exact location of the vehicle with reference to the driver's input.

Afterward, the ECU processes this input data. However, if the sensor data varies suddenly, the ESP detects that the vehicle is facing a difficult driving condition. Thus, the system can detect that if there is an obstacle in the path or a very sharp turn. In such cases, the system applies the desired braking force only on the wheels in need. And thus, it restores the driver control over the vehicle.

This system has more advantage compared to the ABS and TCS systems. This is because it can actually predict the driving behavior of the vehicle. When the Electronic Stability Program comes into action, it gives an indication in the form of a glowing indicator in the instrument cluster. In most of the cases, the driver does not feel any difference in the vehicle except the enhanced control when the ESP starts working.

Figure 2-Vehicle travel with and without ESP

While referring to the Electronic Stability Program or Electronic Stability Control, the majority of vehicle manufacturers use term ESP. However, some manufacturers use the following custom acronyms.