The first electrical power steering system was present in Suzuki Cervo in the year 1988. Electrical Power Steering Pump is also known as Electric Power Assist Steering Pump. This uses an electric motor to assist the driver of the vehicle. These are very helpful and economical when compared to hydraulic power steering systems. They provide more assistance at lower speeds and less assistance at higher speeds. This system can be turned on or turned off manually.
Electric Power Steering system consists of the following basic parts. They are as follows –
- Steering Angle Sensor
- Torque Sensor
- Speed Sensor
- Motor
- Gear
- Electrical Control Unit is often known as ECU.
The torque sensor has two independent wire coils. One coil detects the turn when it is to the left side and the another coil detects the turn when it is to the right side. When the vehicle is in movement, the speed sensors detect the speed, torque, and position of the vehicle and send the signals to the electrical control unit. The electrical control unit operates and controls the motor which connects to the steering gear or steering column with the help of two coils present in the in the torque sensor. The electrical control unit provides variable amounts of assistance depending on the driving conditions. When there is a failure of any component, a rack, and a pinion mechanism acts as a backup system for electrical power steering.
There are usually three electric power steering modes. They are as follows –
Normal Mode – Left and right assist in steering are provided by an Electric control unit in response to the inputs by the driver of the vehicle. The level of assist decreases as the speed of the vehicle increases and the level of assist increases as the speed of the vehicle decreases.
Assist Limitation Mode – This mode comes to the play only when there is a problem with sending the information to an electrical control unit or receiving the information from the electrical control unit. Overheating may also lead to malfunctioning of the electric power steering system and sometimes may damage the circuits.
Assist Off Mode – In this mode, the help from the electrical control unit is completely turned off and is a free fall. This mode can be turned on manually in some cars but in most of the cars, this mode comes into play when there is a major problem with an electrical control unit.
Advantages of Electrical Power Steering System –
- It is very fuel efficient.
- It is very cost efficient and so is very economical when compared to hydraulic systems.
- Varying amounts of assistance can be implemented based on the driver of the vehicle and speed of the vehicle.
- It is very helpful in emergency situations.
- It completely eliminates the use of belt driven engine accessory.
- It eliminates the limitation of a hydraulic pump.
- It is very low in cost.
- It decreases the weight of the vehicle.
- The stability of the vehicle will be improved even in the turns.
- The manufacturing cost is very low.
- The ECU can be simply changed with code.
- The maintenance cost involved is low and has no fluid leakages.
- Moreover, the ECU does not use engine’s power supply.
