EPS SYSTEM : System Description

DESCRIPTION

• The EPS system controls the power steering solenoid valve with 4WAS main control unit.
• The power steering solenoid valve control changes the power steering solenoid valve activation voltage according to the vehicle speed.
  Fig 1: Steering Solenoid Valve Activation Voltage Graph

  Courtesy of NISSAN MOTOR CO., U.S.A.

SYSTEM DIAGRAM

Fig 2: EPS System Diagram

Courtesy of NISSAN MOTOR CO., U.S.A.

Sectional View

Fig 3: Sectional View Of EPS System

Courtesy of NISSAN MOTOR CO., U.S.A.

OPERATION PRINCIPLE

When turning the steering wheel to the right.

During Parking

Fig 4: EPS System Operation Principle Diagram (Parking)

Courtesy of NISSAN MOTOR CO., U.S.A.

1. Power steering solenoid valve is closed while a vehicle is stopped.
2. Pinion "1R", "2R" and "3R" are closed depending on steering torque of steering wheel.
3. Oil pressure "P" in the gear housing assembly is the sum of oil pressures occurring in "2R" and "3R". This results in a light steering force because of high pressure.

During High-speed Operation

Fig 5: EPS System Operation Principle Diagram (High-Speed Operation)

Courtesy of NISSAN MOTOR CO., U.S.A.

1. Power steering solenoid valve is opened during high-speed operation.
2. Pinion "1R", "2R" and "3R" are closed depending on steering torque of steering wheel.
3. "2R" is bypassed to the return port by the EPS solenoid valve.
4. Oil pressure "P" in the gear housing assembly includes only oil pressure occurring in "3R" and results in a heavy steering force.