What is Electric Power Steering? Best for Car or Not?

Power steering is used in the car to steer the vehicle easily with less effort. There are many types of power steering systems used in a car that help to reduce the effort of the driver. In this article, I will discuss what is electric power steering and what are the advantages of using this system in a car.


What is Electric Power Steering?

As the name of this system “Electrical power steering”, this system uses an electrical motor similar to the starter motor in a car, that reduces the effort of the steering system. In this system, the mechanical force is less than the engine power, and the energy is restored for saving. In the power steering system, where everything is under control by the electrical sensors, the system delivers the precise work, and the lag disappears.

In the electric power steering system the electric motor is used in the system to drive the mechanism. The rack and pinion type gearbox is used in the system. The electric power is generated in the motor and delivers the mechanical power to the steering gearbox.

In this system, the steering gearbox is also used as it changes the rotary motion into the linear motion of the shaft.

Parts of Electric Power Steering


An electric power steering system uses an electric motor, which generates the current. But, some other parts are also used in the system to deliver the precise work. These parts are-

  1. Electric Motor.
  2. Electronic Control Unit.
  3. Torque Sensor.
  4. Steering Sensor.
  5. Gearbox.
  6. Steering Linkages.

#1. Electric Motor

In this system, the DC motor is used to generate the electric current. This electric motor receives the signal from the sensor or the ECU and generates the current into it. An electric motor should be capable of doing the mechanical work of changing the direction of the car.

#2. Electronic Control Unit(ECU)

The ECU is the main and unsung hero of this system. This ECU is important to receive and transfer the signal to the motor. ECU takes the information from the vehicle speed sensor and the steering sensor. In this system, the ECU controls the current and the steering mechanism.

The ECU also helps to determine the malfunction in the system, as it is fully controlled electronically the data can be read and the system can be restored by some work. EPS can also be integrated with safety features, such as lane-keeping assistance and stability control systems.

#3. Torque Sensor

The torque sensor measures the force applied to the steering wheel, and the steering angle sensor detects the angle at which the steering wheel is turned. The torque sensor is situated on both the input and output shafts, as the driver turns the steering wheel, the torque sensor measures the amount of force or torque applied to the wheel.

The torque sensor translates the mechanical force applied to the steering wheel into an electrical signal. This electrical signal is then sent to the control unit or electronic control module of the EPS system.

#4. Steering Sensor

The steering sensor is also called a Rotating or steering angle sensor. This sensor is located in the steering box, in the gearbox system. As the signal comes from the ECU this steering sensor helps to steer the vehicle according to the signal. The steering sensor also helps to convert the electrical power into mechanical as it rotates the mechanical equipment to point in a direction.

#5. Gearbox

In this system, the reduction gearbox is used. The reduction gearbox increases the torque generated by the electric motor before it is applied to the steering mechanism. The reduction gearbox helps to keep the electric motor within its optimal operating range, improving overall system efficiency and reducing energy consumption.

By adjusting the gear ratio, the system can provide a balance between ease of steering at low speeds (such as during parking) and a firmer, more controlled feel at higher speeds (such as on the highway).

#6. Steering Linkages

The steering linkage is a connection of various links between the steering gearbox and the front wheels. The motion of the pitman’s arm of the steering gearbox is transferred to the steering knuckles of the front wheels through the steering linkage.

When the steering wheel is turned to the left or right the pitman arm swings from one side to the other. This movement of the pitman gives angular movement to the front wheels through the linkages.

Read more – Torque Converter Construction and Working Diagram.

Working of Electric Power Steering


The electrical power steering system relies on the sensors and the electric motor. When the driver turns the wheel, the steering sensor senses the turn. This sensor is attached to the steering column and sends the electric message to the ECU.

Then, the EPS control unit, also known as the electronic control module (ECM), processes information from various sensors, including the torque sensor, steering angle sensor, and vehicle speed sensor. Based on these inputs, the control unit determines the appropriate level of assistance needed and sends commands to the electric motor.

Then the electricity takes the specific amount of electricity from the battery and generates the electricity into it. The electric motor needs to produce the torque as given the sense from the steering sensor. Then this torque is delivered through the torque sensor and the actuators.

The gears are placed on a shaft, that is attached to the electric motor. Then the pinion(where the motor output shaft connects the system) rotates and transfers the torque to the rack. This transfer of torque then turns the rack and the vehicle turns left or right.


The advantages of this system are –

  1. The primary advantage of power steering is the significant reduction in the amount of physical effort required to turn the steering wheel.
  2. This system reduced the hydraulic oil system. That’s why the time-to-time oil change is not needed.
  3. This system uses fewer components and relies on the electric sensors that’s why it is environment friendly and has a greater fuel economy.
  4. The design is simple and has a better servicing process.
  5. Drivers can enjoy smoother and more controlled steering inputs, contributing to a more relaxed ride.
  6. This system can help the driver in autopilot mode.
  7. The electric power steering system also provides the lane-changing warning sensor, automatic parking sensor, lane-changing sensor, etc.


If there are advantages then there are disadvantages also. The disadvantages of this system are-

  1. Because of the advanced sensors and the equipment the vehicle cost is very high.
  2. If there are some malfunctions in the system then the specialized trained technician can only repair or change the part.
  3. Electric power steering systems rely on electrical power to function. In the event of an electrical system failure or power loss, the steering assistance may be compromised, making steering more difficult for the driver.
  4. The production and disposal of electric power steering components, particularly batteries and electric motors, can have environmental impacts. Proper disposal and recycling practices are crucial to mitigate these concerns.
  5. In certain EPS systems, there may be a reduction in steering feel at higher speeds, which could affect driver confidence and control on the highway.

Conclusion on What is Electric Power Steering

In modern cars the electric power steering system is important to provide better steering control on the road and when parking. This system allows the driver good handling and better riding comfort. In this system, the electric motor is the main and important component that helps the system to run better. I hope you will like the article.

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