A transmission control device (4) includes: a gear ratio calculating unit (4a) for calculating a target gear ratio of a transmission (2) based on a gear ratio control mode, to thereby control the transmission; an electric motor drive torque calculating unit (4b) for calculating a drive torque of an electric motor (9) based on the gear ratio control mode when drive of the electric motor (9) is permitted; and an engine torque calculating unit (4c) for calculating an output torque of an engine (1) based on the gear ratio control mode so as to achieve a best fuel efficiency operation state. The gear ratio calculating unit (4a) switches processing of calculating a gear ratio based on whether or not the drive of the electric motor (9) is permitted.

A transmission control device (4) includes: a gear ratio calculating unit (4a) for calculating a target gear ratio of a transmission (2) based on a gear ratio control mode, to thereby control the transmission; an electric motor drive torque calculating unit (4b) for calculating a drive torque of an electric motor (9) based on the gear ratio control mode when drive of the electric motor (9) is permitted; and an engine torque calculating unit (4c) for calculating an output torque of an engine (1) based on the gear ratio control mode so as to achieve a best fuel efficiency operation state. The gear ratio calculating unit (4a) switches processing of calculating a gear ratio based on whether or not the drive of the electric motor (9) is permitted.

A method is described for operating a motor vehicle, in which control is applied, in the context of a drive-off operation, to an electrical machine operable in motor mode in order to deliver a torque driving the vehicle, control simultaneously being applied to a braking system of the motor vehicle in such a way that it applies a braking torque.

A method is described for operating a motor vehicle, in which control is applied, in the context of a drive-off operation, to an electrical machine operable in motor mode in order to deliver a torque driving the vehicle, control simultaneously being applied to a braking system of the motor vehicle in such a way that it applies a braking torque.

Aspects of the present invention relate to a method and to a control system for a vehicle, the vehicle comprising an internal combustion engine configured to provide torque to a first axle of the vehicle for generating first axle wheel torque, and an electric machine configured to provide torque to a second axle of the vehicle for generating second axle wheel torque, the method comprising: outputting a torque request for the engine and a torque request for the electric machine, the torque requests having a first ratio dependent on a required torque split between the first axle wheel torque and the second axle wheel torque, wherein received first axle wheel torque and received second axle wheel torque have a second variable ratio dependent on a difference between wheel torque response capabilities of the engine and of the electric machine; determining that a trigger condition is satisfied; and controlling, in dependence on satisfaction of the trigger condition, determination of the torque request for the electric machine such that deviation of the second ratio from the first ratio is inhibited.

Embodiments of the present invention provide An electric machine control system for a vehicle, the electric machine control system comprising one or more controllers, wherein the vehicle comprises an electric machine arranged to be selectively coupleable to provide torque to at least one wheel of an axle of the vehicle, the control system comprising input means (330) to receive at least one attribute signal (410-4X0) indicative of one or more attributes of the vehicle (100), output means (340) arranged to output a coupling signal (345) to control coupling of the electric machine to the at least one wheel of the axle (222), and processing means (310) arranged to determine (1310) a coupling state of the electric machine (212) to the at least one wheel of the axle in dependence on the at least one attribute signal, wherein the processing means is arranged to control the output means to output the coupling signal (345) indicative of the determined coupling state, wherein the processing means is arranged to defer (1320, 1330) controlling the output means to output the coupling signal indicative of a change in the coupling state until expiry of a predetermined period of time since a last change in the coupling state indicated by the coupling signal.

Embodiments of the present invention provide An electric machine control system for a vehicle, the electric machine control system comprising one or more controllers, wherein the vehicle comprises an electric machine arranged to be selectively coupleable to provide torque to at least one wheel of an axle of the vehicle, the control system comprising input means to receive a speed signal indicative of a speed of the vehicle, processing means arranged to determine a coupling state of the electric machine to the at least one wheel of the axle in dependence on the speed signal, and output means arranged to output a coupling signal indicative of the coupling state to control coupling of the electric machine to the at least one wheel of the axle.

Aspects of the present invention relate to a method (400) and to a control system (208) for controlling at least one electric machine (212, 216) of a vehicle (10) to support diagnostic testing of a vehicle system (30) comprising an internal combustion engine (202), wherein the method (400) comprises: controlling a torque output (420) of the at least one electric machine (212,216) to allow a vehicle drive torque demand (410) to be met while the internal combustion engine (202) is operated within at least one torque threshold (432) for the diagnostic testing or operated at a torque setpoint (438) for the diagnostic testing.

Embodiments of the present invention provide an electric machine control system for a vehicle, the electric machine control system comprising one or more controllers, wherein the vehicle comprises an electric machine arranged to be selectively coupleable to provide torque to at least one wheel of an axle of the vehicle, the control system comprising input means to receive at least one attribute signal indicative of one or more attributes (410, 420, 430) of the vehicle and an efficiency signal (440) indicative of selection of an efficiency-based driving mode, output means arranged to output a coupling signal to control coupling of the electric machine to the at least one wheel of the axle, processing means arranged to determine (1510) a first coupling state of the electric machine to the at least one wheel of the axle in dependence on the at least one attribute signal and to determine (1520) a second coupling state of the electric machine to the at least one wheel of the axle in dependence on the at least one efficiency signal, wherein the processing means is arranged to control (1540) the output means to output the coupling signal indicative of the first and second coupling states when the same, and to output (1550) the coupling signal indicative of the first coupling state when the determined first and second coupling states differ.

Aspects of the present invention relate to a method and to a control system for a vehicle, the method comprising: receiving a torque request for an internal combustion engine configured to mechanically couple to a first axle of the vehicle; determining a shortfall relative to the torque request, dependent on torque providable by the engine; and providing an output to control an electric machine to provide a compensation torque configured to compensate for the shortfall, wherein the electric machine is mechanically coupled to a second axle of the vehicle.