A method for reducing the fuel consumption of a mild hybrid vehicle

Method for reducing fuel consumption in hybrid motor vehicle which has an engine, multi-speed transmission, electric machine (e.g. motor / generator, BISG, CISG), and a battery, where an engine speed limit is set and used to determine a transmission ratio change point to optimise fuel consumption, the engine speed limit depending on a state of charge of the battery (SOC). The engine speed limit may depend on battery charge level permitting a temporary torque boost from the electric machine, hence engine speed limit could be set lower than if the SOC was insufficient. Baseline engine speed and second lower adjusted engine speed limits may be pre-set. A state of charge threshold may be used to ascertain whether a torque boost is possible. Gear change may be upshift or downshift. Transmission may be manual, resulting in a driver alert, or automatic, causing automatic shift.