Electric vehicle having a hydraulic brake system

Claim 1

An electric-powered vehicle having a drive system which comprises: at least one electric motor which has an electrical supply and is controlled and monitored by an electric control system driving at least one vehicle wheel in a drive mode of operation of the motor and also varying the electric torque to selectively provide a contribution to an overall braking torque of the vehicle when controlled by said control system to operate in a braking mode, which also includes a hydraulic braking system which is actuated by a vehicle driver, and which operates on at least front wheels of the vehicle, a first mechanism adjusting hydraulic braking torque, produced by the vehicle driver by way of the hydraulic braking system in such a manner that, for modulating overall braking torque effective at said wheels, variation of electric torque produced by said motor stays within a regenerative range of operation of the electric motor, said first mechanism comprising an electronically controlled booster enabling a variable booster ratio to be selected electronically a second mechanism controlling the electrical supply to the electric motor and modulating said overall braking torque for braking in an ABS anti-lock mode such that, if excessive wheel slip occurs, the electric motor torque is reduced; and a third mechanism allowing control of the braking system when hydraulic brake torque alone exceeds wheel locking torque, by which the electric brake torque produced by said electric motor is removed, and an additional tractive torque is then produced by said electric motor and applied to counteract the hydraulic brake torque.