What is Electronic Stability Control (ESC) in Cars and How It Works?

Accidents are a common occurrence on the streets nowadays. Sudden incidents such as a pedestrian crossing the road, slippery surfaces, potholes, or obstacles can make you take unexpected and sudden turns. 

This can sometimes result in losing control of your vehicle. Due to such reasons, your vehicle should be properly equipped with safety components such as electronic stability control. 

Read on to learn more about this car safety feature and its pros and cons. 

As mentioned, ECS is an important safety feature in a car that prevents you from losing control of your vehicle. The main function of ESC is to prevent skidding when you are cornering, taking a sudden turn, or manoeuvring. 

With the help of ECS, the brakes apply automatically on the wheels, and you stay in control of your vehicle even during the most unexpected incidents. 

Apart from applying brakes, the system also detects a few more factors, such as throttle, steering, and rotation around the vertical axis of your car, to detect loss of stability or control. 

The primary function of ESC is to prevent you from losing control of your car due to spinning out or ploughing out. If applied effectively, the system can prevent the most dangerous form of single-car crash or accident – rollover. 

• There are a number of sensors that detect the direction of your car, the brakes on your car's tyre, and the position of your steering wheel. 

• If they detect that the car is not following the direction as intended, the system applies brakes on one or more wheels selectively and controls the speed to bring it back on track. 

• Spin-outs or plough-outs most effectively occur when you take sudden sharp, or quick turns. Slippery or uneven roads increase the chances of such accidents. Hence, you should be careful when taking turns in such road conditions and adjust your speed and following distance.

Now that you know what ESC does, it’s time to take a look at the components that make the whole process possible: 

• Steering Angle Sensor

The steering angle sensor detects the rotation angles of the steering wheel. Two other sensors are attached to it for detection on the steering wheel shaft – magnetic gears and a Hall Effect sensor. 

• Yaw Rate Sensor 

A yaw rate sensor detects the vehicle’s rotation. To measure this angle, the sensor utilises a micro-electromechanical gyroscope. The function of the gyroscope is to measure the Coriolis force acting on the vehicle and figure out how much rotation the car has made about its centre of gravity.  

• Wheel Speed Sensor

Each wheel of a car comes with a wheel speed sensor. This sensor comprises a perforated magnetic ring and a Hall Effect sensor. The magnetic field created by the ring changes as the wheel makes rotation. The function of a Hall Effect sensor is to collect and utilise this data to figure out the speed of the wheels. 

• Engine Control Module 

An engine Control Module, or ECM, is an ECU or electronic control unit that monitors several actuators and sensors in the engine area. This helps ECM in controlling and adjusting the power supplied by the engine. 

• Anti-Lock Braking System 

ABS or anti-lock braking system controls how much pressure should be applied to the tyres even though you control the brakes manually by pressing the brake pedals. In emergencies, ABS manages the hydraulic system to stabilise the car. 

• ECU

ECU monitors your car's critical functions, and there is more than one ECU in a car. ECU tracks the fuel and air entering the engine and performs other similar tasks. ECUs communicate with each other to enable features like Adaptive Cruise Control System, Automatic Emergency Braking, and Lane-Keeping Assist. 

Here are some of the reasons why ESC is an irreplaceable component in a vehicle: 

• It is not humanely possible to control every situation, such as how a vehicle reacts to different surfaces, friction on slippery or wet surfaces, etc. 

• Road conditions can change at any time, and accidents occur unannounced. 

• Along with ESC, stability and traction control are also available. 

• Driving through challenging environments is easier with safety and stability control systems. 

Now that you have learned about the functioning of Electronic Stability Control (ESC) in a car, you might be wondering about the situations in which it comes into action. Take a look at the following points to discover the answer.

• Suppose the vehicle is not moving in the direction intended by the driver. In that case, the ESC activates and adjusts the vehicle's course or helps prevent/minimise skidding during emergency manoeuvres.

• ESC in cars engages when it detects a loss of control over steering. It continuously monitors the inputs from your steering wheel.

• Over-correcting can occur when the vehicle experiences oversteer or understeer due to misjudging a corner or encountering a slippery road surface.

• The system also triggers when the driver abruptly turns the steering wheel too far during emergencies to regain vehicle control. This type of manoeuvre is known as over-correcting.

Here are some of the key advantages of Electronic Stability Control in cars: 

• ESC serves as a driver assistance feature, particularly in challenging driving conditions. For example, if you encounter slippery roads, the stability control system can assist in correcting your vehicle's trajectory if you lose control.

• One of the key advantages of ESC is its efficiency. It automatically activates and applies the brakes on individual wheels without human intervention.

• It effectively prevents serious accidents by eliminating skidding. When a vehicle skids out of control, there is a risk of rollover. ESC helps prevent such incidents.

• In emergencies where you must steer or brake forcefully, ESC helps you maintain control over your car, ensuring stability and safety.

Like everything else, along with advantages, ESC has some drawbacks too: 

• Despite being an important safety feature, ESC has limited effectiveness in enhancing cornering performance, especially at higher speeds. As it is primarily designed for controlled cornering, it cannot significantly improve traction during aggressive driving. This limitation is often observed as one of the common issues with electronic stability control.

• The presence of ESC can sometimes lead drivers to become overconfident and push their vehicles beyond safe limits. However, if the cornering speed exceeds a certain threshold, the safety feature may not be able to intervene effectively. Consequently, the car may ultimately lose control, highlighting the importance of responsible driving even with ESC in place.

• The system can unnecessarily intervene in certain situations, particularly when engaging in aggressive driving manoeuvres in a closed environment. For instance, if you take your car to a race track and attempt to drift, the ESC may restrict your actions. However, some vehicles offer the option to partially or completely disable the stability control system.

Here are some tips which you may find useful while driving using ESC: 

• ESC and ABS work in their finest ways when your car's tyres are properly inflated and in neat condition. 

• Your car's anti-lock braking system must be in optimum working condition for ESC to work properly. The ESC may not work at all when there are glitches in ABS. 

• The most common causes of ABS malfunctioning include dirt or air in the brake fluid and worn brake linings. 

Electronic Stability Control is one of the primary safety features in a car and works in unison with other safety controls. Hence, you need to ensure that all of them are working properly in order to ensure optimum safety while driving.