NEXON BSVI MCE - SERVICE MANUAL

ELECTRONIC STABILITY CONTROL INTEGRETED PROGRAM (ESCi) 1 1 ELECTRONIC STABILITY CONTROL INTEGRATED PROGRAM (ESCi) 1.1 GENERAL INFORMATION A NECESSITY OF ESCi AND TCS The road grip available to the vehicle can vary greatly as a result of road conditions, weather, tyres etc. Whenever a wheel looses its grip with the road surface, the vehicles’ stability and controllability is ultimately affected. I. TRACTION CONTROL SYSTEM (TCS) When starting off or accelerating if the driver gives too much throttle the driven wheels can loose traction with the road surface. This can occur when accelerating from stand still on the flat or a hill, accelerating after a gear change, through a corner or just by increasing the throttle suddenly on a slippery road. If the front wheels loose traction the vehicle will tend to understeer where as if the rear wheels loose traction the vehicle may tend towards over steer. This effect can be magnified if available grip is different for each side of the vehicle. The primary function of the traction control system is to prevent the vehicle from entering these unstable conditions by controlling the vehicles’ longitudinal accelerations and hence enhancing the driving safety. In addition the TCS by regulating the optimum slip levels and emulating the function of a differential lock prevents the wheels from spinning and increases the traction capability of the vehicle. This is achieved through a combination of brake control regulating the torque being transferred to the road at each driving wheel, and engine torque management regulating the amount of torque available. II. Vehicle Dynamic controller (VDC) A vehicle can reach it critical limits for many reasons be it through environmental influences such as a sudden change in the road surface, adverse weather conditions, an obstacle appearing in the road, or making a sudden steering input or simply due to driving at an inappropriate speed. When a vehicle reaches it critical limits it can becomes uncontrollable. Any one of these conditions could cause the vehicle to yaw about its axis, and it is in these situations that ESCi has been developed to support the driver by reacting to the rotational and lateral accelerations of the vehicle. The ESCi monitors the driver inputs and vehicle responses through the various sensors when the system detects that the vehicle is becoming unstable and no longer following the driver intended course i.e. starting to under or over steer it induces a corrective yaw moment to the vehicle through the application of one of the wheel brakes, usually combined with a reduction in the engine torque. ESCi is a recognised vehicle safety system but can only work within the physical limits of the vehicle and environment, and is not a substitute for responsible driving. III. HYDRAULIC BRAKE ASSIST (HBA) In an emergency braking situation the best stopping performance will only be reached if the driver brakes quickly and with sufficient force to bring all four wheels to ABS control. Research has shown that while many drivers apply the brakes quickly in an emergency but often do not apply sufficient force to achieve the best possible stopping distance. The function of the Hydraulic Brake Assist is to detect the emergency brake application and to boost to the brake pressure hence enabling a normal driver to achieve the best possible stop. Value Added functions configured with ESCi 9.2 A. Hill Hold Control Hill Hold Control is a comfort function. The main intend is to prevent the vehicle from rolling backwards while driving off up-hill on an inclined surface. B. Hill decent control HDC is a comfort function, which assists the driver descending a hill by means of active brake intervention. Therefore, the vehicle speed is limited without driver´s help. This function works in both forward and reverse gear (in reverse gear, thresholds for operation may vary). Activation and deactivation of the HDC-function are done by pressing the HDC button on the dashboard. C. Roll over mitigation Rollovers are dangerous incidents and have a higher fatality rate than other kinds of crashes. The main feature of the Roll Movement Functions is the detection of a rollover critical situation, and to mitigate the vehicle rollover. This function try to prevent friction-induced roll-over. This is done by active brake interventions on selected wheels, thereby reducing the tire side forces that cause a roll-over situation.