HEXA

ELECTRONIC STABILITY PROGRAM (ESP) INTRODUCTION Electronic Stability Program (ESP) with Traction Control system (TCS) and Hydraulic Brake Assist (HBA) has evolved from the Anti lock Braking System (ABS). Where the ABS only aids the driver during braking the TCS will apply control to support the driver when accelerating, and the ESP will provide control supporting the driver when a critical situation such as skidding is detected. This could occur as a result of making a sudden emergency evasive swerve to avoid an object in the road or when cornering on a slippery road or trying to turn at higher speeds. ESP will only be able prevent the vehicle from skidding away as long as the vehicle remains within its physical limits. The ESP integrates with the ABS using a common hydraulic unit with attached ECU and containing a pressure sensor. The wheel speed sensors are common and in addition ESP has a steering wheel angle sensor and a combined yaw rate and lateral acceleration sensor. The system is also connected to the engine management system via the integrated vehicle network (IVN) or High speed CAN BUS. The ESP monitors the vehicles’ dynamic behavior and driver inputs and when it detects a situation where the vehicle is starting to understeer (moving straight ahead without responding to the steering) or oversteer (breaking away from the rear) . It will support the driver by applying individual brake controls combined with engine torque reductions to counter the under or oversteer behaviour. The TCS prevents the driven wheels from spinning when the driver is accelerating via a combination of individual brake interventions and engine torque reductions. This way it improves the vehicle traction and stability. The HBA monitors how the driver applies the brake by monitoring the brake pressure increases. If the system detects an emergency brake application it assists the driver by building up the brake pressure in the wheels to achieve full ABS braking.