US Patent 9725083 Vehicle and method of control thereof

The invention provides a speed control system and method for a hybrid electric vehicle, the vehicle having an engine (121), an electric machine (123) and a mode switch (169), to allow switching between a first speed control mode (EV) and a second speed control mode (HEV). When the control system is in the first mode and at least one of a prescribed one or more conditions is met, e.g. a rate of acceleration demanded by the driver or a difference between a target vehicle speed and a current vehicle speed exceeds a respective prescribed threshold value, the system is operable to not limit operation of the vehicle to the EV mode.