EPS System

EPS SYSTEM

System Description

EPS CONTROL UNIT





^ EPS control unit performs an arithmetical operation on data, such as steering wheel turning force (sensor signal) from the torque sensor, vehicle speed signal, etc. Then it generates an optimum assist torque to the EPS motor according to the driving condition.
^ EPS control unit decreases the output to EPS motor while extremely using the power steering function (e.g., full steering) for protecting EPS motor and EPS control unit (Protect overload status). While activating protect overload status, the assist torque gradually decreases, and the steering wheel turning force becomes heavy. The normal assist torque reactivates by not steering.
^ In case of an error in the electrical system, the fail-safe function stops output signals to the EPS motor. Then the previous state is changed to the manual steering state.
^ Self-diagnosis can be done with CONSULT-III.

EPS MOTOR
EPS motor provides the assist torque by control signal from EPS control unit.

TORQUE SENSOR





Torque sensor detects the steering torque, and transmit the signal to EPS control unit.

REDUCTION GEAR
Reduction gear increases the assist torque provided from EPS motor with worm gears, and outputs to the column shaft.

EPS WARNING LAMP
Turns ON when there is a malfunction in EPS system. It indicates that fail-safe mode is engaged and enters a manual steering state (Control turning force steering wheel becomes heavy).

Also turns ON when ignition switch is turned ON, for purpose of lamp check. Turns OFF after the engine starts if system is normal.

EPS Warning Lamp Indication





Schematic





COMPONENTS FUNCTION DESCRIPTION





CAN Communication

SYSTEM DESCRIPTION
CAN (Controller Area Network) is a serial communication line for real time application. It is an on-vehicle multiplex communication line with high data communication speed and excellent error detection ability. Many electronic control units are equipped onto a vehicle, and each control unit shares information and links with other control units during operation (not independent). In CAN communication, control units are connected with 2 communication lines (CAN-H line, CAN-L line) allowing a high rate of information transmission with less wiring. Each control unit transmits/receives data but selectively reads required data only.

For details, refer to LAN-23, "CAN System Specification Chart". CAN System Specification Chart