EPS System Description - Overview
This vehicle is equipped with electrical power steering (EPS). The driver's steering force is assisted by an electric motor at the steering gearbox, instead of an engine-driven oil pump to generate oil pressure, so the EPS system improves engine efficiency.
The EPS control unit monitors and controls the EPS motor's assisting force to match driving conditions.
- Low vehicle speeds: High power assist (for easy handling)
- High speed driving: Low power assist (for stable driving)
- Low speed to high speed driving: Change smoothly from high assist to low assist
The steering force from the steering wheel is sent to the pinion shaft. The torque sensor measures the difference in torque between the applied force to the pinion shaft and the resistance on the wheels due to road friction, then the torque sensor sends a voltage signal to the EPS control unit. Based on this signal, the EPS control unit controls the current to the EPS motor. The EPS motor transmits its power through a cogged belt and a ball screw mechanism to push the steering rack right or left.