Traction Control System (TCS)

TRACTION CONTROL SYSTEM (TCS)

FUNCTION

1. Main performance
1) Traction: Lower vibration and higher launchability, acceleration and climbability by slip control.
2) Cornering and passing: Stable cornering and passing.
3) Steering stability: Control traction force traverse vector prior to provide easy turning when turning the steering wheel.

2. General TCS features
1) Improved driveablity: Minor operation of acceleration is not necessary in launching and acceleration on slippery road.
2) More stable cornering by stable acceleration on normal road condition.
3) TCS system will compare vehicle speed received from rear wheel speed sensor and driving wheel speed from front wheel speed sensor on slippery road condition, and provide optimum slipping rate of driving wheels.

TYPE

FULL TRACTION CONTROL SYSTEM (FTCS)

1. ABS ECM controls TCS control too.
2. ECM will compare signals from front (driving) and rear wheel speed sensors to detect driving wheels slip.
3. Upon detecting driving wheels slip, ECM will perform TCS control. The TCS control will include brake TCS (BTCS) control.
4. ABS ECM will transmit engine torque reduction request, fuel cut cylinder number, and TCS control request signals in accordance with slip level to engine ECM and TCU through BUS line which will provide CAN communication for TCS control.
5. Engine ECM will perform fuel cut as requested by ABS ECM and retard ignition timing as per engine torque reduction request signal.
6. TCU will hold shift position by TCS control time according to TCS operation signal. Then enhanced acceleration by kick-down will not occur.

BRAKE TRACTION CONTROL SYSTEM (BTCS)

1. On TCS control, only brake control will be performed. (engine and TCU control will not happen)
2. Controlled by motor pump output pressure.





TRACTION CONTROL SYSTEM (TCS)

1. NORMAL MODE





^ In the normal driving condition, TC valve (normally open) is the passage between the master cylinder and each wheel cylinder.
^ When brake pedal is applied, brake pressure is delivered to the wheel cylinders via NO-TC valve and all solenoid valves inside the hydraulic unit are deactivated.
^ In case of TCS malfunction, it does not affect brake operation.





2. PRESSURE INCREASE MODE





^ If a front wheel spin is detected, TCS begins a brake control to decrease a wheel spin.
^ Hydraulic shuttle valve (HSV) is opened. Brake fluid is supplied from the master cylinder by motor operation to the spin wheel via HSV
^ TC valve is closed (ON). Brake pressure generated from motor pump is delivered only to the front wheel.
^ Inlet valve remains open to deliver the brake pressure generated from motor pump to the spinning wheels.





3. PRESSURE DUMP MODE





^ When the wheel deceleration is under the threshold and the wheel spin is reduced under a slip threshold, applied brake pressure is reduced to get an optimum traction force.
^ Outlet valve is open to release the brake pressure and inlet valve is closed to block the pressure increase from the motor pump.
^ Hydraulic shuttle valve (HSV) remains opened, TC valve is ON.
^ Motor is ON, to dump the brake fluid being released from the lock-up wheel.





4. PRESSURE HOLD MODE