How Electric power Steering can be useful to reduce the fuel consumption and pollution? what are the advantages of EPS over conventional steering

What is an Electric power steering

The Electric power steering is the combination of a mechanical steering system with an electrically controlled electric motor, its major difference from the conventional steering is that the hydraulic system is replaced by an electrical system. The desired torque will be created by the help of an electric motor

An electric motor is used to drive either the power steering hydraulic pump or the steering linkage directly so that the power steering function is independent of the engine speed and due to that energy saving can be done

Difference between conventional and Electric steering

Conventional steering uses an engine accessory belt to drive the pump. pressurized fluids are provided that operates a piston in power steering gear or actuator to assist the driver. In case of the electric power steering, a motor is used to drive the pump, and the speed of the pump is regulated by an electric controller to vary the flow and pump pressure.

In case of electric power steering, the pump can run at low speed or it can be turned off in straight-ahead lines to achieve the energy-saving

  • Energy consumption is less in Electric power steering
  • Provides optimal steering force according to the driving speed
  • Steering stability is increased while driving at high speed
  • Fuel consumption is reduced in the electric power steering
  • Electric steering will only consume energy when the steering wheel is turned
  • There is no need for parts such as steering pump, hydraulic hose, pump pulley, oil reservoir… so less space is required
  • There is no need for hydraulic oil, so environment protection can be done
  • Active return function will provide better balance in every riding condition


The electric motor is attached to the steering rack by through gear mechanism in electric steering, many types of motor and gas drives are possible. Microprocessor-based steering dynamics and driver effort is needed for its operation

In the input shaft a steering sensor is located where it enters the gearbox housing there are two types of steering sensor one is torque sensor which converts steering torque inputs and its direction to voltage signals and a rotation sensor which converts the direction and rotation speed into voltage signals.

A microcontroller steering unit monitors the inputs from the steering sensor and from the vehicle speed sensor. The inputs are checked to determine how much power is needed after that the control unit sends a command to the power unit which will supply current to an electric motor. According to the flow of the voltage, the motor pushes the rack to right or left. The power assist can be improved by increasing the current to the motor.

What are the Functions of Electric power Steering

  • It will help to swing the wheels left and right
  • Less effort is needed to turn the vehicle
  • Directional stability
  • Wear and tear of the tyres can be controlled
  • Self-retuning effect is achieved
  • It can absorb the road shock and it will prevent it from reaching the driver

Advantages over conventional steering system

  • EPS is less expensive and flexible
  • Due to ‘active return to center’ less driver effort is needed to return to center
  • Improved vehicle stability and safety
  • Reduction in steering pull while accelerating is done by active torque damping
  • Acceleration and fuel economy is improved due to engine independence
  • Power steering is available even when the engine is off