Electronic Stability Control (ESC) - Simple Explanation

Electronic Stability Control (ESC) is one of the popular feature available in cars which is highly recommended to avoid accidents. Some of its other names are Electronic Stability Program (ESP), StabiliTrak, Vehicle Stability Assist (VSA), Vehicle Stability Control (VSC), Vehicle Dynamic Control (VDC), Dynamic Stability Control (DSC), and Active Stability Control (ASC). Ok...Let us see why do we need ESC? and how does it work? in this article.

If you enter your car in a curve too fast and start to lose control of your vehicle, you might not safely make it through the turn. Electronic Stability Control (ESC) is a feature that can help us to avoid this type of accidents. Most of the fatal passenger vehicle crashes on roads involve a single vehicle that happened due to loss of stability and ESC can reduce these type of crashes. ESC is an extension of the anti-lock braking system with speed sensors and independent braking for each wheel.

Additional ESC sensors continuously monitor a driver's steering input. So, they can tell if the wheel is pointed in the intended direction on slippery roads, curves, and in emergency maneuvers. When the front end of a vehicle may start to plow ahead or the rear end may spin out, the ESC will help to apply the brake on individual wheels to maintain control in the vehicle. ESC also reduces engine speed to bring the car back into the intended line of travel. ESC assists the driver in situations like understeering, oversteering and sudden maneuvers and helps to maintain the stability on icy or slippery roads. If every vehicle on the road has ESC, we can definitely avoid more accidents.

Main Components of Electronic Stability Control (ESC):

• Steering angle sensor
• Wheel speed sensor
• Control module
• Yaw rate sensor
• Acceleration sensors
• Hydraulic modulator

Steering angle sensor 

It is used to determine where the front wheels of the car are pointing. The steering angle can be measured with the help of optical sensors, by assessing the Hall effect and through other technologies. These sensors measure the angle of movement of the steering wheel in degrees.

Wheel speed sensor

It monitors the speed of the wheels.

Control module

The control module is used to detect the discrepancy between the intended path and the actual path by communicating with the steering angle sensor and yaw rate sensor. In case of an over-steering situation, the control module would apply the brake to the front outside wheel to keep the vehicle under control.

Yaw rate sensor

This sensor is used to determine where the car is exactly pointing. A Yaw Rate Sensor measures a vehicle’s angular velocity about its vertical axis in degrees or radians per second in order to determine the exact orientation of the vehicle. So, by comparing the vehicle’s actual yaw rate to the target yaw rate, the onboard computer can identify at what degree the vehicle will under- or over-steer, and what corrective action the system should take. Corrective action may include reducing engine power or speed as well as applying the brake on one or more wheels to realign the vehicle to maintain the stability.

Acceleration sensors

It measures lateral and longitudinal acceleration acting on the car in order to calculate its actual position. It is used to detect whether the vehicle is sliding.

Hydraulic modulator

The hydraulic modulator is used to optimize the brake pressure on each wheel to increase or decrease the wheel speed accordingly to maintain vehicle stability.

Some other automotive safety-related articles:
Automotive Safety systems- Introduction
Anti-lock braking system
Traction Control System (TCS) - Simple Explanation
Adaptive Cruise Control (ACC)
Tire (Tyre) Pressure Monitoring System (TPMS) - Simple Explanation
Lane Departure Warning (LDW) - Simple Explanation
Night Vision System (NVS) in Automobiles - Simple Explanation