Control system and method for an electric vehicle

1 . A control system, comprising one or more controllers, for an electric vehicle, the control system comprising:

an input arranged to receive a temperature signal indicative of a temperature of a transmission associated with a traction electric machine of the vehicle;

an output arranged to output a flow control signal for controlling one or more valves and/or pumps to control a flow of lubricant fluid associated with the traction electric machine and the transmission through a heat exchanger, the flow control signal being indicative of a proportion of the flow of lubricant fluid through the heat exchanger and at least one bypass fluid path, respectively, the at least one bypass fluid path comprising one or more conduits allowing a circulation of the lubricant fluid between the traction electric machine and the transmission bypassing the heat exchanger; and

an electronic processing device arranged to (i) control the output to output the flow control signal in dependence on the temperature signal and (ii) determine the proportion of the flow of lubricant through the heat exchanger and the at least one bypass fluid path in dependence on the temperature signal.

2 . The control system of claim 1 , wherein electronic processing device is arranged to control the output to output the flow control signal in dependence on the temperature signal to cause the traction electric machine to heat the transmission.

3 . The control system of claim 1 , wherein:

the output is arranged to output a heat control signal for causing the electric machine to operate in a loss operating mode for heating the lubricant fluid; and

the electronic processing device is arranged to control the output to output the heat control signal in dependence on the temperature signal.

4 . The control system of claim 3 , wherein the electronic processing device is arranged to control the output to output the heat control signal whilst the vehicle is stationary.

5 . The control system of claim 1 , wherein the electronic processing device is arranged to control the output to output the flow control signal in dependence on a temperature threshold.

6 . The control system of claim 5 , wherein

the electronic processing device is arranged to determine the proportion of the flow of lubricant fluid through the heat exchanger to maintain the temperature of the transmission above the temperature threshold.

7 . The control system of claim 1 , wherein:

the input is arranged to receive a heat request signal indicative of a request for heating of one or both of a traction battery of the vehicle and a cabin of the vehicle; and

the electronic processing device is arranged to control the output to output the flow control signal in dependence on the heat request signal.

8 . A coolant system for the traction electric machine of the vehicle, comprising:

the heat exchanger for exchanging thermal energy between the lubricant fluid and a coolant fluid;

the one or more pumps and/or valves for controlling the flow of the lubricant fluid through the heat exchanger, wherein the lubricant fluid is associated with the traction electric machine and the transmission of the traction electric machine; and

the control system according to claim 1 , wherein the one or more pumps and/or valves is arranged to receive the flow control signal from the control system and to control the flow of lubricant fluid through the heat exchanger in dependence thereon.

9 . The coolant system of claim 8 , comprising at least one bypass fluid path for allowing at least a portion of the flow of lubricant fluid to bypass the heat exchanger, wherein the one or more pumps and/or valves is arranged to control a proportion of the flow of lubricant fluid through the heat exchanger and the at least one bypass fluid path respectively in dependence on the flow control signal.

10 . The coolant system of claim 8 comprising a coolant fluid circuit arranged to circulate the coolant fluid therethrough via the heat exchanger, wherein the coolant fluid circuit comprises either a traction battery circuit for circulating the coolant fluid in thermal communication with a traction battery of the vehicle for heating the traction battery; or a cabin heating circuit for circulating the coolant fluid in thermal communication with a cabin heater of the vehicle for heating a cabin of the vehicle.

11 . A vehicle comprising the coolant system according to claim 8 .

12 . A vehicle comprising the control system according to claim 1 .

13 . A computer-implemented method, comprising:

receiving a temperature signal indicative of a temperature of a transmission associated with a traction electric machine of a vehicle; and

controlling flow of a proportion of lubricant fluid associated with the traction electric machine and the transmission of the vehicle through a heat exchanger and at least one bypass fluid path in dependence on the temperature signal,

wherein the at least one bypass fluid path comprises one or more conduits allowing a circulation of the lubricant fluid between the traction electric machine and the transmission bypassing the heat exchanger.

14 . The method of claim 13 , comprising:

determining the proportion of the flow of lubricant fluid through the heat exchanger and the at least one bypass fluid path, respectively; and

controlling the flow of lubricant fluid in dependence on the determined proportion.

15 . The method of claim 14 , wherein the proportion of the flow of lubricant fluid through the heat exchanger is determined to maintain the temperature of the transmission above a temperature threshold.

16 . A non-transitory computer readable medium storing software which, when executed by a computer, is arranged to cause the computer to perform the method according to claim 13 .