A device and a method for controlling vehicle speed in a vehicle equipped with cruise control when the vehicle is travelling downhill. The method involves driving a vehicle downhill with the cruise control set to a first brake set speed value; detecting a current vehicle speed; applying a brake torque using at least one auxiliary brake to maintain the first brake set speed, which brake torque is dependent on a currently engaged gear; detecting a manual request for a downshift from a currently engaged gear to a lower gear, in order to decrease vehicle speed; and determining if a downshift is permissible at the current vehicle speed. If a control unit determines that a downshift is not permissible, then the control unit is automatically arranged to apply a brake torque using at least a vehicle service brake to retard the vehicle speed; to retard the vehicle from a current, first vehicle speed to a lower, second vehicle speed at which a downshift to a lower gear is permissible; and to perform a downshift to a lower gear when the second vehicle speed is reached. The cruise control brake set speed is set to a second brake set speed that is lower than the first cruise control brake set speed value; and a brake torque using at least the auxiliary brake is applied if a detected current vehicle speed exceeds the second brake set speed.
A METHOD AND A SYSTEM FOR CONTROLLING VEHICLE SPEED
2018-08-30
Patent
Electronic Resource
English
IPC: | B60W CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION , Gemeinsame Steuerung oder Regelung von Fahrzeug-Unteraggregaten verschiedenen Typs oder verschiedener Funktion |