four wheel drive KIA CARNIVAL 2007 Workshop Manual

2007 > 2.7L V6 GASOLINE >
description of ESP
Optimum driving safety now has a name : ESP, the Electronic Stability Control.
ESP recognizes critical driving conditions, such as panic reactions in dangerous situations, and stabilizes the vehicle
by wheel- individual braking and engine control intervention with no needfor actuating the brake or the gas pedal.
ESP adds a further function known as Active Yaw Control (AYC) to the ABS, TCS, EBD and ESP functions. Whereas
the ABS/TCS function controls wheel slip during braking and acceleration and, thus, mainly intervenes in the
longitudinal dynamics of the vehicle, active yaw control stabilizes the vehicle about its vertical axis.
This is achieved by wheel individual brake intervention and adaptation of the momentary engine torque with no need
for any action to be taken by the driver.
ESC essentially consists of three assemblies : the sensors, the electronic control unit and the actuators.
Of course, the stability control feature works under all driving and operating conditions. Under certain driving
conditions, the ABS/TCS function can be activated simultaneously with the ESP function in response to a command
by the driver.
In the event of a failure of the stability control function, the basic safety function, ABS, is still maintained.
DESCRIPTION OF ESP CONTROL
ESP system includes ABS/EBD, TCS and AYC (Active yaw control) function.
ABS/EBD function : The ECU changes the active sensor signal (current shift) coming from the four wheel sensors to
the square waveform.By using the input of above signals, the ECU calculates the vehicle speed and the acceleration
& deceleration of the four wheels.And, the ECU judges whether the ABS/EBD should be actuated or not.
TCS function prevents the wheel slip of drive direction by adding the brake pressure and engine torque reduction via
CAN communication.TCS function uses the wheel speed sensor signal to determine the wheel slip as far as ABS
function.
AYC function prevents unstable maneuver of the vehicle. To determine the vehicle maneuver, AYC function uses the
maneuver sensor signals(Yaw Rate Sensor, Lateral Acceleration Sensor, Steering Wheel Angle Sensor).If vehicle
maneuver is unstable (Over Steer or Under Steer), AYC function applies the brake pressure on certain wheel, and
send engine torque reduction signal by CAN.
After the key - on, the ECU continually diagnoses the system failure. (self- diagnosis)If the system failure is detected,
the ECU informs driver of the system failure through the BRAKE/ABS/ESP warning lamp. (fail- safe warning)