Description And Operation

DESCRIPTION 

Antilock Brake System (ABS) 

The Electronic Stability Control (ESC) system on the vehicle is a sophisticated four-channel (independent control of all four wheels on the vehicle) active management system. The dynamic control system helps the driver to maintain control in difficult or adverse conditions such as wet, snow-covered or icy roads, tight corners and evasive maneuvers.

The ESC system determines the driver's intentions and maintains dynamic control of the vehicle in general to keep the dynamic forces within the safety limits in all driving conditions, doing this nearly transparently, so that the control seems almost intuitive.

The ESC system primarily complements the ABS and traction control, to control all four wheels of the vehicle independently in accordance with the signals from the yaw sensor and steering angle sensor. The algorithm of the system determines when to intervene on the basis of the data received from the following sensors: wheel speed, yaw, lateral acceleration, master cylinder pressure, steering angle and vehicle speed.

If the driver pushes the vehicle so that it exceeds the grip limits of the road surface and that the vehicle overseers or understeers, the system instantaneously analyses the data input from the sensors and corrects the loss of control by applying one, several or all of the brakes to adjust the yaw rate, maintaining the vehicle in the direction set by the driver.

OPERATION 

The ESC system includes the following functions:

• Activation of brake lights above a deceleration threshold  permits the indication of vehicle deceleration to other vehicles by simulating braking. This function permits the activation of the brake lights for at least 1 second in two situations: during the operation of the Adaptive Cruise Control (ACC), Hill Descent Control (HDC) or Hill Start Assist (HSA), the brake lights are activated when the brake fluid pressure exceeds a minimum threshold value; during ESC or Trailer Sway Control (TSC), when the deceleration exceeds the set threshold.
• Dynamic Steering Control (DST - Dynamic Steering Torque)  uses the integration of the ESC system with the Electric Power Steering (EPS) to increase the level of safety on the whole vehicle. In critical situations (understeer, oversteer, braking on surfaces with different grip conditions), through the DST function, the ESC system controls the steering, providing additional torque on the steering wheel, to suggest the most appropriate maneuver to the driver. The coordinated action of the brakes and steering increases the sensation of safety and control of the vehicle.
• Electronic Brake Pre-fill (EBP)  detects whether the driver raises their foot from the accelerator pedal and, if detected, the brake module applies light braking pressure (not enough to decelerate the vehicle) to ensure that the brake pads are aligned correctly in anticipation of emergency braking.
• Electronic Roll Mitigation (ERM)  uses the information from the ESC system sensors to determine in advance whether the vehicle is at risk of entering a potential rollover situation, then activates the brakes individually and requests that the Powertrain Control Module reduce the torque provided if necessary.
• Electronic Traction Control (BLD - Electronic Brake Differential)  applies braking force to the wheel of a single axle which is slipping in order to permit both wheels on the axle to receive a sufficient drive torque value, thus improving the traction in all road and weather conditions.
• Hill Descent Control (HDC)  maintains vehicle speed while descending hills in off-road driving conditions by applying the brakes when necessary. HDC can only be enabled when the transfer case is in the "4WD LOW" position and the vehicle speed is less then 48 km/h (30 mph). If these conditions are not met while attempting to use the HDC feature, the HDC indicator light will flash ON/OFF. The HDC indicator lamp will be ON solid when HDC is enabled. When enabled, HDC senses the terrain and activates when the vehicle is descending a hill. HDC is only intended for low speed off-road driving. The accelerator pedal will override HDC at any time.
• Hill Start Assist (HSA)  allows the driver to move their foot from the brake pedal to the accelerator and keep the vehicle braked in the process. The system maintains the braking pressure for about two seconds after the release of the brake pedal. The system reduces the braking pressure on the wheel's calipers in accordance with the pressure on the accelerator pedal.
• Hydraulic Boost Failure Compensation (HBFC)  detects failure in the brake servo (vacuum loss) through a sensor. If failure is detected, the brake module activates the ABS pump to assist braking.
• Panic Brake Assist (PBA)  detects emergency braking by measuring the brake operation speed and increases the braking power if necessary. In certain conditions, the braking assistance may activate the ABS more rapidly compared to vehicles that don't have this function. The more rapid intervention of the ABS has the potential to reduce the stopping distance, compensating for the delayed intervention of the driver on the brakes.
• Trailer Sway Control (TSC)  reduces the sway of the vehicle caused by the trailer that may occur in adverse conditions (side wind and traffic). The system monitors the motion of the vehicle with respect to the trajectory envisaged by the driver and applies alternate pressure to the brakes to slow down the vehicle then increases the pressure on a front wheel to counteract the effect of the trailer.