Patent Publication Number: US-2023150352-A1

Title: Oil Temperature Control Method, Controller, Powertrain, and Electric Vehicle

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This claims priority to Chinese Patent Application No. 202111331434.6 filed on Nov. 10, 2021, which is hereby incorporated by reference in its entirety. 
     TECHNICAL FIELD 
     This disclosure relates to the field of electric vehicle technologies, and in particular, to an oil temperature control method, a controller, a powertrain, and an electric vehicle. 
     BACKGROUND 
     A powertrain of an electric vehicle includes a motor, an inverter, a cooling system, and the like. With technology evolution, a cooling system in the powertrain dissipates heat for a motor, an inverter, and the like by using an oil cooling circuit, and transfers heat of the oil cooling circuit to a water cooling circuit by using an oil-water heat exchanger. 
     However, viscosity of an oil coolant varies greatly with temperature. The viscosity increases at a low temperature. In this case, heat exchange capability decreases. In an actual test, when a temperature of an oil coolant of a brand is 40 degrees Celsius (° C.), viscosity is 24.9 millipascal seconds (mPa·s). When the temperature is −40° C., the viscosity is 12030 mPa·s. There is an increase of three orders of magnitude, and correspondingly a heat dissipation effect is also much worse. Therefore, how to control an oil temperature of the oil coolant to be within a specific range to avoid great degradation of heat dissipation performance of the powertrain due to large-scale fluctuation of oil temperatures is an urgent problem that needs to be resolved. 
     SUMMARY 
     Embodiments of this disclosure provide an oil temperature control method, a controller, a powertrain, and an electric vehicle, so as to control an oil temperature in an oil cooling circuit to be within a target temperature range. 
     According to a first aspect, an embodiment of this disclosure provides an oil temperature control method, applied to a controller of an electric vehicle that includes an oil cooling circuit, where the oil cooling circuit flows through a motor and an inverter. The method includes the following steps: determining an oil temperature at a detection point, where the detection point is a specified location in the oil cooling circuit; when the oil temperature is lower than a first target temperature, triggering one or more of the following operations: bypassing an oil-water heat exchanger, reducing a water flow rate, and increasing a power of an oil pump; or when the oil temperature is higher than a second target temperature, triggering one or more of the following operations: disabling a bypass path of an oil-water heat exchanger, increasing a water flow rate, and reducing a power of an oil pump. 
     It should be noted that, reducing the water flow rate may be maintaining a water flow and reducing the water flow rate, or may be stopping the water flow. The water flow rate may be adjusted by adjusting a valve in a water circuit, or may be adjusted by changing a rotation speed of a water pump or in another manner. For example, the water flow rate may be reduced by reducing the rotation speed of the water pump, or the water flow rate may be increased by increasing the rotation speed of the water pump. A specific implementation method is not limited herein. 
     In some possible implementations, the oil temperature at the detection point may be an oil temperature of the oil pump, an oil temperature of the motor, an oil temperature at an inverter inlet, an oil temperature at an inverter outlet, or the like. 
     In this implementation, the controller triggers different operations based on the oil temperatures at the detection point in the oil cooling circuit, to enable the oil temperature to be located between the first target temperature and the second target temperature, so as to control an oil temperature in a refrigeration circuit to be within a target range. 
     With reference to the first aspect of embodiments of this disclosure, in some possible implementations, the determining an oil temperature at a detection point includes: directly obtaining the oil temperature at the detection point by using a sensor; or obtaining a first specified parameter, and determining the oil temperature at the detection point based on the first specified parameter, where the first specified parameter includes one or more of the following parameters: a current of the oil pump, a rotation speed of the oil pump, a current of the motor, a rotation speed of the motor, a water flow rate, and a water temperature. 
     With reference to the first aspect of embodiments of this disclosure, in some possible implementations, the first target temperature and the second target temperature are determined based on a second specified parameter, and the second specified parameter includes operating scenario parameters of the electric vehicle. 
     With reference to the first aspect of embodiments of this disclosure, in some possible implementations, the operating scenario parameters of the electric vehicle include a current location of the electric vehicle, and/or a current date, and/or an operation mode of the electric vehicle, where the operation mode includes a motion mode and a normal mode. 
     According to a second aspect, an embodiment of this disclosure provides a controller, applied to an electric vehicle that includes an oil cooling circuit, where the oil cooling circuit flows through a motor and an inverter. The controller includes: a determining unit, configured to determine an oil temperature at a detection point, where the detection point is a specified location in the oil cooling circuit; and a processing unit, configured to: when the oil temperature is lower than a first target temperature, trigger one or more of the following operations: bypassing an oil-water heat exchanger, reducing a water flow rate, and increasing a power of an oil pump, and configured to: when the oil temperature is higher than a second target temperature, trigger one or more of the following operations: disabling a bypass path of an oil-water heat exchanger, increasing a water flow rate, and reducing a power of an oil pump. 
     It should be noted that, reducing the water flow rate may be maintaining a water flow and reducing the water flow rate, or may be stopping the water flow. The water flow rate may be adjusted by adjusting a valve in a water circuit, or may be adjusted by changing a rotation speed of a water pump or in another manner. For example, the water flow rate may be reduced by reducing the rotation speed of the water pump, or the water flow rate may be increased by increasing the rotation speed of the water pump. A specific implementation method is not limited herein. 
     With reference to the second aspect of embodiments of this disclosure, in some possible implementations, the determining unit is specifically configured to: directly obtain the oil temperature at the detection point by using a sensor; or obtain a first specified parameter, and determine the oil temperature at the detection point based on the first specified parameter, where a first specified parameter set includes one or more of the following parameters: a current of the oil pump, a rotation speed of the oil pump, a current of the motor, a rotation speed of the motor, a water flow rate, and a water temperature. 
     With reference to the second aspect of embodiments of this disclosure, in some possible implementations, the processing unit is further configured to determine the first target temperature and the second target temperature based on a second specified parameter, where the second specified parameter includes operating scenario parameters of the electric vehicle. 
     With reference to the second aspect of embodiments of this disclosure, in some possible implementations, the operating scenario parameters of the electric vehicle include a current location of the electric vehicle, and/or a current date, and/or an operation mode of the electric vehicle, where the operation mode includes a motion mode and a normal mode. 
     According to a third aspect, an embodiment of this disclosure provides a powertrain, including: the controller, the inverter, the motor, the water pump, the oil pump, and the oil-water heat exchanger according to any one of the first aspect or the possible implementations of the first aspect. The inverter is configured to convert a direct current into an alternating current and then transmit the alternating current to the motor. The motor is configured to convert the alternating current into mechanical energy to drive an electric vehicle to travel. The controller is configured to control a power of the oil pump and a rotation speed of the water pump. The oil-water heat exchanger is configured to transfer heat of an oil cooling circuit to a water cooling circuit. 
     According to a fourth aspect, an embodiment of this disclosure provides an electric vehicle, including: the powertrain according to the third aspect and a power battery pack, where the power battery pack is configured to provide a direct current for the inverter. 
     According to a fifth aspect, an embodiment of this disclosure provides a computer-readable storage medium, where the computer storage medium stores a computer program, the computer program includes program instructions, and when the program instructions are executed by a processor, the processor is enabled to implement the oil temperature control method according to any one of the first aspect or the possible implementations of the first aspect. 
     According to a sixth aspect, an embodiment of this disclosure provides a computer program product, where the computer program product includes a non-transitory computer-readable storage medium that stores a computer program, and the computer program can be operated to enable a computer to implement the oil temperature control method according to any one of the first aspect or the possible implementations of the first aspect. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       To describe the technical solutions in embodiments of this disclosure more clearly, the following illustrates the accompanying drawings used in embodiments of this disclosure. 
         FIG.  1    is a schematic diagram of a structure of a powertrain integrated with an oil-cooled inverter according to an embodiment of this disclosure. 
         FIG.  2 A  is a schematic diagram of an oil temperature curve. 
         FIG.  2 B  is a schematic diagram of another oil temperature curve. 
         FIG.  2 C  is a schematic diagram of an oil temperature curve within a target oil temperature range. 
         FIG.  3 A- 1    and  FIG.  3 A- 2    are a schematic flowchart of an oil temperature control method according to an embodiment of this disclosure. 
         FIG.  3 B- 1    and  FIG.  3 B- 2    are a schematic flowchart of an oil temperature control method according to an embodiment of this disclosure. 
         FIG.  3 C- 1    and  FIG.  3 C- 2    are a schematic flowchart of an oil temperature control method according to an embodiment of this disclosure. 
         FIG.  3 D- 1    and  FIG.  3 D- 2    are a schematic flowchart of an oil temperature control method according to an embodiment of this disclosure. 
         FIG.  4 A- 1    and  FIG.  4 A- 2    are a schematic flowchart of an oil temperature control method according to an embodiment of this disclosure. 
         FIG.  4 B- 1    and  FIG.  4 B- 2    are a schematic flowchart of an oil temperature control method according to an embodiment of this disclosure. 
         FIG.  4 C- 1    and  FIG.  4 C- 2    are a schematic flowchart of an oil temperature control method according to an embodiment of this disclosure. 
         FIG.  4 D- 1    and  FIG.  4 D- 2    are a schematic flowchart of an oil temperature control method according to an embodiment of this disclosure. 
         FIG.  5    is a schematic diagram of a structure of a powertrain according to an embodiment of this disclosure. 
         FIG.  6    is a schematic diagram of a structure of a network device according to an embodiment of this disclosure. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     The following describes embodiments of this disclosure with reference to the accompanying drawings in embodiments of this disclosure. 
       FIG.  1    is a schematic diagram of a structure of a powertrain integrated with an oil-cooled inverter according to this disclosure. 
     The powertrain integrated with an oil-cooled inverter mainly includes a controller  101 , an inverter  102 , a motor  103 , an oil pump  104 , a water pump  105 , an oil-water heat exchanger  106 , and the like. The inverter  102  is configured to convert a direct current into an alternating current and then transmit the alternating current to the motor  103 . The motor  103  is configured to convert the alternating current into mechanical energy to drive an electric vehicle to travel. The controller  101  is configured to control a power of the oil pump  104  and a rotation speed of the water pump  105  based on an oil temperature at a detection point in an oil cooling circuit. The oil-water heat exchanger  106  is configured to transfer heat of the oil cooling circuit to a water cooling circuit. 
     A cooling system in the powertrain includes the water cooling circuit and the oil cooling circuit. The water cooling circuit and the oil cooling circuit are not connected. The oil cooling circuit is configured to dissipate heat for the inverter  102  and the motor  103 . The water cooling circuit flows through the oil-water heat exchanger  106 . The oil-water heat exchanger  106  includes both a path that belongs to the water cooling circuit and a path that belongs to the oil cooling circuit, and is configured to dissipate heat for the oil cooling circuit by using the water cooling circuit. In specific implementation, the controller  101  determines the oil temperature at the detection point, where the detection point may be a specified location in the oil cooling circuit. For example, the oil temperature at the detection point may be an oil temperature of the oil pump, an oil temperature of the motor, an oil temperature at an inverter inlet, an oil temperature at an inverter outlet, or the like. The controller  101  may directly obtain the oil temperature at the detection point by using a sensor, or obtain a specified parameter, and determine the oil temperature at the detection point based on the specified parameter. The specified parameter may include one or more of the following parameters: a current of the oil pump, a rotation speed of the oil pump, a current of the motor, a rotation speed of the motor, a water flow rate, a water temperature, and the like. When the oil temperature is lower than a first target temperature, the controller  101  triggers one or more of the following operations: bypassing the oil-water heat exchanger, reducing a water flow rate, increasing the power of the oil pump, and the like. When the oil temperature is higher than a second target temperature, the controller  101  triggers one or more of the following operations: disabling a bypass path of the oil-water heat exchanger, increasing a water flow rate, and reducing the power of the oil pump. It should be noted that, the first target temperature and the second target temperature may be preset fixed values, or may be values determined based on motion scenario parameters of the electric vehicle. The motion scenario parameters of the electric vehicle may include a current location of the electric vehicle, and/or a current date, and/or an operation mode of the electric vehicle, where the operation mode of the electric vehicle may include a motion mode and a normal mode. 
     In this implementation, the controller triggers different operations based on the oil temperatures at the detection point in the oil cooling circuit, to enable the oil temperature to be located between the first target temperature and the second target temperature, so as to control an oil temperature in a refrigeration circuit to be within a target range. 
       FIG.  2 A  is a schematic diagram of an oil temperature curve. As shown in  FIG.  2 A , T 1  is the first target temperature, and T 2  is the second target temperature. The oil temperature curve shows that an initial oil temperature is lower than the first target temperature T 1 , and a final oil temperature is higher than the second target temperature T 2 . 
       FIG.  2 B  is a schematic diagram of another oil temperature curve. As shown in  FIG.  2 B , T 1  is the first target temperature, and T 2  is the second target temperature. The oil temperature curve shows that an initial oil temperature is between the first target temperature T 1  and the second target temperature T 2 , and a final oil temperature is higher than the second target temperature T 2 . 
       FIG.  2 C  is a schematic diagram of an oil temperature curve in a target temperature range. As shown in  FIG.  2 C , T 1  is the first target temperature, and T 2  is the second target temperature. The oil temperature curve shows that an oil temperature is between the first target temperature T 1  and the second target temperature T 2 . A target temperature curve controlled by using the controller is also that an oil temperature curve is between the first target temperature T 1  and the second target temperature T 2 . This helps improve a heat dissipation effect of the powertrain integrated with an oil-cooled inverter. 
     To make a person skilled in the art understand the technical solutions in this disclosure better, the following describes the technical solutions in embodiments of this disclosure with reference to the accompanying drawings in embodiments of this disclosure. 
     The terms such as “first” and “second” in this disclosure are merely intended for a purpose of description, and shall not be understood as an indication or implication of relative importance or implicit indication of a quantity of indicated technical features. 
     In addition, in this disclosure, orientation terms such as “up” and “down” may include but are not limited to orientations schematically placed relative to components in the accompanying drawings. It should be understood that these directional terms may be relative concepts, and are used for relative description and clarification, and may be correspondingly changed based on changes in placement orientations of the components in the accompanying drawings. In this disclosure, unless otherwise expressly specified and limited, the term “connection” should be understood in a broad sense. For example, “connection” may be a fixed connection, a detachable connection, or an integrated connection, or may be a direct connection or an indirect connection through an intermediate medium. In this disclosure, when an oil cooling circuit is described, for ease of description, a “circuit” or a “path” may be used instead of a “pipeline” in a physical structure or a container that can carry a cooling medium. 
     Embodiment 1 
     This embodiment of this disclosure provides an oil temperature control method, which is described in detail below with reference to  FIG.  3 A- 1    and  FIG.  3 A- 2   .  FIG.  3 A- 1    and  FIG.  3 A- 2    are a schematic flowchart of an oil temperature control method according to an embodiment of this disclosure. The method is applied to a controller of an electric vehicle that includes an oil cooling circuit. The oil cooling circuit flows through a motor and an inverter. The oil temperature control method includes the following steps. 
       301 : Obtain a detection instruction. 
     For example, if the detection instruction may be triggered by default after the electric vehicle is started, the controller obtains the detection instruction after the electric vehicle is started. It may be understood that, the detection instruction may be alternatively triggered by another operation or event, which is not limited herein. 
       302 : Determine whether a detection stopping instruction is obtained. 
     If yes, a control procedure ends. If no, step  303  is performed. 
       303 : Determine an oil temperature at a detection point. 
     In some possible implementations, the oil temperature at the detection point may be obtained by using a temperature sensor. In some other embodiments, a first specified parameter may be obtained, and the oil temperature at the detection point is determined based on the first specified parameter. The first specified parameter may include one or more of the following parameters: a current of an oil pump, a rotation speed of the oil pump, a current of the motor, a rotation speed of the motor, a water flow rate, a water temperature, and the like. The oil temperature at the detection point may be an oil temperature of the oil pump, an oil temperature of the motor, an oil temperature at an inverter inlet, an oil temperature at an inverter outlet, or the like. 
       304 : Determine whether the oil temperature meets the following condition: T 2 ≤the oil temperature≤T 1 . 
     If yes, step  302  is performed. If no, step  305  is performed. T 1  is a first target temperature, and T 2  is a second target temperature. The first target temperature T 1  and the second target temperature T 2  may be preset fixed values, or may be values determined based on motion scenario parameters of the electric vehicle. The motion scenario parameters of the electric vehicle may include a current location of the electric vehicle, and/or a current date, and/or an operation mode of the electric vehicle, and/or the like, where the operation mode of the electric vehicle may include a motion mode, a normal mode, and the like. 
       305 : Determine whether the oil temperature is less than T 2 . 
     If yes, step  3061  is performed. If no, step  3091  is performed. 
       3061 : Bypass an oil-water heat exchanger and/or reduce a water flow rate. 
     It should be noted that, these control manners may be used separately or in combination as required. 
     It should be noted that, reducing the water flow rate may be maintaining a water flow and reducing the water flow rate, or may be stopping the water flow. The water flow rate may be adjusted by adjusting a valve in a water circuit, or may be adjusted by changing a rotation speed of a water pump or in another manner. For example, the water flow rate may be reduced by reducing the rotation speed of the water pump, or the water flow rate may be increased by increasing the rotation speed of the water pump. A specific implementation method is not limited herein. 
       307 : Determine whether a power of the oil pump is less than X1. 
     If yes, step  308  is performed. If no, step  302  is performed. 
       308 : Increase the power of the oil pump. 
     It should be noted that, in some possible implementations, the power of the oil pump may be increased by a predetermined value each time. The predetermined value may be a fixed value, or may be a value changed based on a specified condition. Step  307  may be performed again every predetermined time to determine whether an adjusted power of the oil pump is less than X1. 
       3091 : Disable a bypass path of an oil-water heat exchanger and/or increase a water flow rate. 
       310 : Determine whether the power of the oil pump is greater than X2. 
     If yes, step  311  is performed. If no, step  3091  is performed. 
       311 : Reduce the power of the oil pump. 
     It should be noted that, in some possible implementations, the power of the oil pump may be reduced by a predetermined value each time. Step  310  may be performed again every predetermined time to determine whether an adjusted power of the oil pump is greater than X2. 
     In this implementation, the controller triggers different operations based on the oil temperatures at the detection point in the oil cooling circuit, to enable the oil temperature in the oil cooling circuit to be located between the first target temperature and the second target temperature. 
     Embodiment 2 
     This embodiment of this disclosure provides an oil temperature control method, which is described in detail below with reference to  FIG.  3 B- 1    and  FIG.  3 B- 2   .  FIG.  3 B- 1    and  FIG.  3 B- 2    are a schematic flowchart of an oil temperature control method according to an embodiment of this disclosure. The method is applied to a controller of an electric vehicle that includes an oil cooling circuit. The oil cooling circuit flows through a motor and an inverter. The oil temperature control method includes the following steps. 
       301 : Obtain a detection instruction. 
     For example, if the detection instruction may be triggered by default after the electric vehicle is started, the controller obtains the detection instruction after the electric vehicle is started. It may be understood that, the detection instruction may be alternatively triggered by another operation or event, which is not limited herein. 
       302 : Determine whether a detection stopping instruction is obtained. 
     If yes, a control procedure ends. If no, step  303  is performed. 
       303 : Determine an oil temperature at a detection point. 
     In some possible implementations, the oil temperature at the detection point may be obtained by using a temperature sensor. In some other embodiments, a first specified parameter may be obtained, and the oil temperature at the detection point is determined based on the first specified parameter. The first specified parameter may include one or more of the following parameters: a current of an oil pump, a rotation speed of the oil pump, a current of the motor, a rotation speed of the motor, a water flow rate, a water temperature, and the like. The oil temperature at the detection point may be an oil temperature of the oil pump, an oil temperature of the motor, an oil temperature at an inverter inlet, an oil temperature at an inverter outlet, or the like. 
       304 : Determine whether the oil temperature meets the following condition: T 2 ≤the oil temperature≤T 1 . 
     If yes, step  302  is performed. If no, step  305  is performed. T 1  is a first target temperature, and T 2  is a second target temperature. The first target temperature T 1  and the second target temperature T 2  may be preset fixed values, or may be values determined based on motion scenario parameters of the electric vehicle. The motion scenario parameters of the electric vehicle may include a current location of the electric vehicle, and/or a current date, and/or an operation mode of the electric vehicle, and/or the like, where the operation mode of the electric vehicle may include a motion mode, a normal mode, and the like. 
       305 : Determine whether the oil temperature is less than T 2 . 
     If yes, step  3062  is performed. If no, step  310  is performed. 
       3062 : Bypass an oil-water heat exchanger and/or reduce a water flow rate. 
     It should be noted that, these control manners may be used separately or in combination as required. 
       307 : Determine whether a power of the oil pump is less than X1. 
     If yes, step  308  is performed. If no, step  302  is performed. 
       308 : Increase the power of the oil pump. 
     It should be noted that, in some possible implementations, the power of the oil pump may be increased by a predetermined value each time. The predetermined value may be a fixed value, or may be a value changed based on a specified condition. Step  307  may be performed again every predetermined time to determine whether an adjusted power of the oil pump is less than X1. 
       310 : Determine whether the power of the oil pump is greater than X2. 
     If yes, step  311  is performed. If no, step  3092  is performed. 
       3092 : Disable a bypass path of an oil-water heat exchanger and/or increase a water flow rate. 
       311 : Reduce the power of the oil pump. 
     It should be noted that, in some possible implementations, the power of the oil pump may be reduced by a predetermined value each time. Step  310  may be performed again every predetermined time to determine whether an adjusted power of the oil pump is greater than X2. 
     In this implementation, the controller triggers different operations based on the oil temperatures at the detection point in the oil cooling circuit, to enable the oil temperature in the oil cooling circuit to be located between the first target temperature and the second target temperature. 
     Embodiment 3 
     This embodiment of this disclosure provides an oil temperature control method, which is described in detail below with reference to  FIG.  3 C- 1    and  FIG.  3 C- 2   .  FIG.  3 C- 1    and  FIG.  3 C- 2    are a schematic flowchart of an oil temperature control method according to an embodiment of this disclosure. The method is applied to a controller of an electric vehicle that includes an oil cooling circuit. The oil cooling circuit flows through a motor and an inverter. The oil temperature control method includes the following steps. 
       301 : Obtain a detection instruction. 
     For example, if the detection instruction may be triggered by default after the electric vehicle is started, the controller obtains the detection instruction after the electric vehicle is started. It may be understood that, the detection instruction may be alternatively triggered by another operation or event, which is not limited herein. 
       302 : Determine whether a detection stopping instruction is obtained. 
     If yes, a control procedure ends. If no, step  303  is performed. 
       303 : Determine an oil temperature at a detection point. 
     In some possible implementations, the oil temperature at the detection point may be obtained by using a temperature sensor. In some other embodiments, a first specified parameter may be obtained, and the oil temperature at the detection point is determined based on the first specified parameter. The first specified parameter may include one or more of the following parameters: a current of an oil pump, a rotation speed of the oil pump, a current of the motor, a rotation speed of the motor, a water flow rate, a water temperature, and the like. The oil temperature at the detection point may be an oil temperature of the oil pump, an oil temperature of the motor, an oil temperature at an inverter inlet, an oil temperature at an inverter outlet, or the like. 
       304 : Determine whether the oil temperature meets the following condition: T 2 ≤the oil temperature≤T 1 . 
     If yes, step  302  is performed. If no, step  305  is performed. T 1  is a first target temperature, and T 2  is a second target temperature. The first target temperature T 1  and the second target temperature T 2  may be preset fixed values, or may be values determined based on motion scenario parameters of the electric vehicle. The motion scenario parameters of the electric vehicle may include a current location of the electric vehicle, and/or a current date, and/or an operation mode of the electric vehicle, and/or the like, where the operation mode of the electric vehicle may include a motion mode, a normal mode, and the like. 
       305 : Determine whether the oil temperature is less than T 2 . 
     If yes, step  307  is performed. If no, step  3093  is performed. 
       307 : Determine whether a power of the oil pump is less than X1. 
     If yes, step  308  is performed. If no, step  3063  is performed. 
       3063 : Bypass an oil-water heat exchanger and/or reduce a water flow rate. 
     It should be noted that, these control manners may be used separately or in combination as required. 
       308 : Increase the power of the oil pump. 
     It should be noted that, in some possible implementations, the power of the oil pump may be increased by a predetermined value each time. The predetermined value may be a fixed value, or may be a value changed based on a specified condition. Step  307  may be performed again every predetermined time to determine whether an adjusted power of the oil pump is less than X1. 
       3093 : Disable a bypass path of an oil-water heat exchanger and/or increase a water flow rate. 
       310 : Determine whether the power of the oil pump is greater than X2. 
     If yes, step  311  is performed. If no, step  302  is performed. 
       311 : Reduce the power of the oil pump. 
     It should be noted that, in some possible implementations, the power of the oil pump may be reduced by a predetermined value each time. Step  310  may be performed again every predetermined time to determine whether an adjusted power of the oil pump is greater than X2. 
     In this implementation, the controller triggers different operations based on the oil temperatures at the detection point in the oil cooling circuit, to enable the oil temperature in the oil cooling circuit to be located between the first target temperature and the second target temperature. 
     Embodiment 4 
     This embodiment of this disclosure provides an oil temperature control method, which is described in detail below with reference to  FIG.  3 D- 1    and  FIG.  3 D- 2   .  FIG.  3 D- 1    and  FIG.  3 D- 2    are a schematic flowchart of an oil temperature control method according to an embodiment of this disclosure. The method is applied to a controller of an electric vehicle that includes an oil cooling circuit. The oil cooling circuit flows through a motor and an inverter. The oil temperature control method includes the following steps. 
       301 : Obtain a detection instruction. 
     For example, if the detection instruction may be triggered by default after the electric vehicle is started, the controller obtains the detection instruction after the electric vehicle is started. It may be understood that, the detection instruction may be alternatively triggered by another operation or event, which is not limited herein. 
       302 : Determine whether a detection stopping instruction is obtained. 
     If yes, a control procedure ends. If no, step  303  is performed. 
       303 : Determine an oil temperature at a detection point. 
     In some possible implementations, the oil temperature at the detection point may be obtained by using a temperature sensor. In some other embodiments, a first specified parameter may be obtained, and the oil temperature at the detection point is determined based on the first specified parameter. The first specified parameter may include one or more of the following parameters: a current of an oil pump, a rotation speed of the oil pump, a current of the motor, a rotation speed of the motor, a water flow rate, a water temperature, and the like. The oil temperature at the detection point may be an oil temperature of the oil pump, an oil temperature of the motor, an oil temperature at an inverter inlet, an oil temperature at an inverter outlet, or the like. 
       304 : Determine whether the oil temperature meets the following condition: T 2 ≤the oil temperature≤T 1 . 
     If yes, step  302  is performed. If no, step  305  is performed. T 1  is a first target temperature, and T 2  is a second target temperature. The first target temperature T 1  and the second target temperature T 2  may be preset fixed values, or may be values determined based on motion scenario parameters of the electric vehicle. The motion scenario parameters of the electric vehicle may include a current location of the electric vehicle, and/or a current date, and/or an operation mode of the electric vehicle, and/or the like, where the operation mode of the electric vehicle may include a motion mode, a normal mode, and the like. 
       305 : Determine whether the oil temperature is less than T 2 . 
     If yes, step  307  is performed. If no, step  310  is performed. 
       307 : Determine whether a power of the oil pump is less than X1. 
     If yes, step  308  is performed. If no, step  3064  is performed. 
       3064 : Bypass an oil-water heat exchanger and/or reduce a water flow rate. 
     It should be noted that, these control manners may be used separately or in combination as required. 
       308 : Increase the power of the oil pump. 
     It should be noted that, in some possible implementations, the power of the oil pump may be increased by a predetermined value each time. The predetermined value may be a fixed value, or may be a value changed based on a specified condition. Step  307  may be performed again every predetermined time to determine whether an adjusted power of the oil pump is less than X1. 
       310 : Determine whether the power of the oil pump is greater than X2. 
     If yes, step  311  is performed. If no, step  3094  is performed. 
       3094 : Disable a bypass path of an oil-water heat exchanger and/or increase a water flow rate. 
       311 : Reduce the power of the oil pump. 
     It should be noted that, in some possible implementations, the power of the oil pump may be reduced by a predetermined value each time. Step  310  may be performed again every predetermined time to determine whether an adjusted power of the oil pump is greater than X2. 
     In this implementation, the controller triggers different operations based on the oil temperatures at the detection point in the oil cooling circuit, to enable the oil temperature in the oil cooling circuit to be located between the first target temperature and the second target temperature. 
     Embodiment 5 
     This embodiment of this disclosure provides an oil temperature control method, which is described in detail below with reference to  FIG.  4 A- 1    and  FIG.  4 A- 2   .  FIG.  4 A- 1    and  FIG.  4 A- 2    are a schematic flowchart of an oil temperature control method according to an embodiment of this disclosure. The method is applied to a controller of an electric vehicle that includes an oil cooling circuit. The oil cooling circuit flows through a motor and an inverter. The oil temperature control method includes the following steps. 
       401 : Obtain a detection instruction. 
     For example, if the detection instruction may be triggered by default after the electric vehicle is started, the controller obtains the detection instruction after the electric vehicle is started. It may be understood that, the detection instruction may be alternatively triggered by another operation or event, which is not limited herein. 
       402 : Determine whether a detection stopping instruction is obtained. 
     If yes, a control procedure ends. If no, step  403  is performed. 
       403 : Determine an oil temperature at a detection point. 
     In some possible implementations, the oil temperature at the detection point may be obtained by using a temperature sensor. In some other embodiments, a first specified parameter may be obtained, and the oil temperature at the detection point is determined based on the first specified parameter. The first specified parameter may include one or more of the following parameters: a current of an oil pump, a rotation speed of the oil pump, a current of the motor, a rotation speed of the motor, a water flow rate, a water temperature, and the like. The oil temperature at the detection point may be an oil temperature of the oil pump, an oil temperature of the motor, an oil temperature at an inverter inlet, an oil temperature at an inverter outlet, or the like. 
       404 : Determine whether the oil temperature meets the following condition: T 2 ≤the oil temperature≤T 1 . 
     If yes, step  402  is performed. If no, step  405  is performed. T 1  is a first target temperature, and T 2  is a second target temperature. The first target temperature T 1  and the second target temperature T 2  may be preset fixed values, or may be values determined based on motion scenario parameters of the electric vehicle. The motion scenario parameters of the electric vehicle may include a current location of the electric vehicle, and/or a current date, and/or an operation mode of the electric vehicle, and/or the like, where the operation mode of the electric vehicle may include a motion mode, a normal mode, and the like. 
       405 : Determine whether the oil temperature is greater than T 1 . 
     If yes, step  4091  is performed. If no, step  4061  is performed. 
       4061 : Bypass an oil-water heat exchanger and/or reduce a water flow rate. 
     It should be noted that, these control manners may be used separately or in combination as required. 
       407 : Determine whether a power of the oil pump is less than X1. 
     If yes, step  408  is performed. If no, step  402  is performed. 
       408 : Increase the power of the oil pump. 
     It should be noted that, in some possible implementations, the power of the oil pump may be increased by a predetermined value each time. The predetermined value may be a fixed value, or may be a value changed based on a specified condition. Step  407  may be performed again every predetermined time to determine whether an adjusted power of the oil pump is less than X1. 
       4091 : Disable a bypass path of an oil-water heat exchanger and/or increase a water flow rate. 
       410 : Determine whether the power of the oil pump is greater than X2. 
     If yes, step  411  is performed. If no, step  402  is performed. 
       411 : Reduce the power of the oil pump. 
     It should be noted that, in some possible implementations, the power of the oil pump may be reduced by a predetermined value each time. Step  410  may be performed again every predetermined time to determine whether an adjusted power of the oil pump is greater than X2. 
     In this implementation, the controller triggers different operations based on the oil temperatures at the detection point in the oil cooling circuit, to enable the oil temperature in the oil cooling circuit to be located between the first target temperature and the second target temperature. 
     Embodiment 6 
     This embodiment of this disclosure provides an oil temperature control method, which is described in detail below with reference to  FIG.  4 B- 1    and  FIG.  4 B- 2   .  FIG.  4 B- 1    and  FIG.  4 B- 2    are a schematic flowchart of an oil temperature control method according to an embodiment of this disclosure. The method is applied to a controller of an electric vehicle that includes an oil cooling circuit. The oil cooling circuit flows through a motor and an inverter. The oil temperature control method includes the following steps. 
       401 : Obtain a detection instruction. 
     For example, if the detection instruction may be triggered by default after the electric vehicle is started, the controller obtains the detection instruction after the electric vehicle is started. It may be understood that, the detection instruction may be alternatively triggered by another operation or event, which is not limited herein. 
       402 : Determine whether a detection stopping instruction is obtained. 
     If yes, a control procedure ends. If no, step  403  is performed. 
       403 : Determine an oil temperature at a detection point. 
     In some possible implementations, the oil temperature at the detection point may be obtained by using a temperature sensor. In some other embodiments, a first specified parameter may be obtained, and the oil temperature at the detection point is determined based on the first specified parameter. The first specified parameter may include one or more of the following parameters: a current of an oil pump, a rotation speed of the oil pump, a current of the motor, a rotation speed of the motor, a water flow rate, a water temperature, and the like. The oil temperature at the detection point may be an oil temperature of the oil pump, an oil temperature of the motor, an oil temperature at an inverter inlet, an oil temperature at an inverter outlet, or the like. 
       404 : Determine whether the oil temperature meets the following condition: T 2 ≤the oil temperature≤T 1 . 
     If yes, step  402  is performed. If no, step  405  is performed. T 1  is a first target temperature, and T 2  is a second target temperature. The first target temperature T 1  and the second target temperature T 2  may be preset fixed values, or may be values determined based on motion scenario parameters of the electric vehicle. The motion scenario parameters of the electric vehicle may include a current location of the electric vehicle, and/or a current date, and/or an operation mode of the electric vehicle, and/or the like, where the operation mode of the electric vehicle may include a motion mode, a normal mode, and the like. 
       405 : Determine whether the oil temperature is greater than T 1 . 
     If yes, step  410  is performed. If no, step  4062  is performed. 
       4062 : Bypass an oil-water heat exchanger and/or reduce a water flow rate. 
     It should be noted that, these control manners may be used separately or in combination as required. 
       407 : Determine whether a power of the oil pump is less than X1. 
     If yes, step  408  is performed. If no, step  402  is performed. 
       408 : Increase the power of the oil pump. 
     It should be noted that, in some possible implementations, the power of the oil pump may be increased by a predetermined value each time. The predetermined value may be a fixed value, or may be a value changed based on a specified condition. Step  407  may be performed again every predetermined time to determine whether an adjusted power of the oil pump is less than X1. 
       410 : Determine whether the power of the oil pump is greater than X2. 
     If yes, step  411  is performed. If no, step  4092  is performed. 
       4092 : Disable a bypass path of an oil-water heat exchanger and/or increase a water flow rate. 
       411 : Reduce the power of the oil pump. 
     It should be noted that, in some possible implementations, the power of the oil pump may be reduced by a predetermined value each time. Step  410  may be performed again every predetermined time to determine whether an adjusted power of the oil pump is greater than X2. 
     In this implementation, the controller triggers different operations based on the oil temperatures at the detection point in the oil cooling circuit, to enable the oil temperature in the oil cooling circuit to be located between the first target temperature and the second target temperature. 
     Embodiment 7 
     This embodiment of this disclosure provides an oil temperature control method, which is described in detail below with reference to  FIG.  4 C- 1    and  FIG.  4 C- 2   .  FIG.  4 C- 1    and  FIG.  4 C- 2    are a schematic flowchart of an oil temperature control method according to an embodiment of this disclosure. The method is applied to a controller of an electric vehicle that includes an oil cooling circuit. The oil cooling circuit flows through a motor and an inverter. The oil temperature control method includes the following steps. 
       401 : Obtain a detection instruction. 
     For example, if the detection instruction may be triggered by default after the electric vehicle is started, the controller obtains the detection instruction after the electric vehicle is started. It may be understood that, the detection instruction may be alternatively triggered by another operation or event, which is not limited herein. 
       402 : Determine whether a detection stopping instruction is obtained. 
     If yes, a control procedure ends. If no, step  403  is performed. 
       403 : Determine an oil temperature at a detection point. 
     In some possible implementations, the oil temperature at the detection point may be obtained by using a temperature sensor. In some other embodiments, a first specified parameter may be obtained, and the oil temperature at the detection point is determined based on the first specified parameter. The first specified parameter may include one or more of the following parameters: a current of an oil pump, a rotation speed of the oil pump, a current of the motor, a rotation speed of the motor, a water flow rate, a water temperature, and the like. The oil temperature at the detection point may be an oil temperature of the oil pump, an oil temperature of the motor, an oil temperature at an inverter inlet, an oil temperature at an inverter outlet, or the like. 
       404 : Determine whether the oil temperature meets the following condition: T 2 ≤the oil temperature≤T 1 . 
     If yes, step  402  is performed. If no, step  405  is performed. T 1  is a first target temperature, and T 2  is a second target temperature. The first target temperature T 1  and the second target temperature T 2  may be preset fixed values, or may be values determined based on motion scenario parameters of the electric vehicle. The motion scenario parameters of the electric vehicle may include a current location of the electric vehicle, and/or a current date, and/or an operation mode of the electric vehicle, and/or the like, where the operation mode of the electric vehicle may include a motion mode, a normal mode, and the like. 
       405 : Determine whether the oil temperature is greater than T 1 . 
     If yes, step  4093  is performed. If no, step  407  is performed. 
       407 : Determine whether a power of the oil pump is less than X1. 
     If yes, step  408  is performed. If no, step  4063  is performed. 
       4063 : Bypass an oil-water heat exchanger and/or reduce a water flow rate. 
     It should be noted that, these control manners may be used separately or in combination as required. 
       408 : Increase the power of the oil pump. 
     It should be noted that, in some possible implementations, the power of the oil pump may be increased by a predetermined value each time. The predetermined value may be a fixed value, or may be a value changed based on a specified condition. Step  407  may be performed again every predetermined time to determine whether an adjusted power of the oil pump is less than X1. 
       4093 : Disable a bypass path of an oil-water heat exchanger and/or increase a water flow rate. 
       410 : Determine whether the power of the oil pump is greater than X2. 
     If yes, step  411  is performed. If no, step  402  is performed. 
       411 : Reduce the power of the oil pump. 
     It should be noted that, in some possible implementations, the power of the oil pump may be reduced by a predetermined value each time. Step  410  may be performed again every predetermined time to determine whether an adjusted power of the oil pump is greater than X2. 
     In this implementation, the controller triggers different operations based on the oil temperatures at the detection point in the oil cooling circuit, to enable the oil temperature in the oil cooling circuit to be located between the first target temperature and the second target temperature. 
     Embodiment 8 
     This embodiment of this disclosure provides an oil temperature control method, which is described in detail below with reference to  FIG.  4 D- 1    and  FIG.  4 D- 2   .  FIG.  4 D- 1    and  FIG.  4 D- 2    are a schematic flowchart of an oil temperature control method according to an embodiment of this disclosure. The method is applied to a controller of an electric vehicle that includes an oil cooling circuit. The oil cooling circuit flows through a motor and an inverter. The oil temperature control method includes the following steps. 
       401 : Obtain a detection instruction. 
     For example, if the detection instruction may be triggered by default after the electric vehicle is started, the controller obtains the detection instruction after the electric vehicle is started. It may be understood that, the detection instruction may be alternatively triggered by another operation or event, which is not limited herein. 
       402 : Determine whether a detection stopping instruction is obtained. 
     If yes, a control procedure ends. If no, step  403  is performed. 
       403 : Determine an oil temperature at a detection point. 
     In some possible implementations, the oil temperature at the detection point may be obtained by using a temperature sensor. In some other embodiments, a first specified parameter may be obtained, and the oil temperature at the detection point is determined based on the first specified parameter. The first specified parameter may include one or more of the following parameters: a current of an oil pump, a rotation speed of the oil pump, a current of the motor, a rotation speed of the motor, a water flow rate, a water temperature, and the like. The oil temperature at the detection point may be an oil temperature of the oil pump, an oil temperature of the motor, an oil temperature at an inverter inlet, an oil temperature at an inverter outlet, or the like. 
       404 : Determine whether the oil temperature meets the following condition: T 2 ≤the oil temperature≤T 1 . 
     If yes, step  402  is performed. If no, step  405  is performed. T 1  is a first target temperature, and T 2  is a second target temperature. The first target temperature T 1  and the second target temperature T 2  may be preset fixed values, or may be values determined based on motion scenario parameters of the electric vehicle. The motion scenario parameters of the electric vehicle may include a current location of the electric vehicle, and/or a current date, and/or an operation mode of the electric vehicle, and/or the like, where the operation mode of the electric vehicle may include a motion mode, a normal mode, and the like. 
       405 : Determine whether the oil temperature is greater than T 1 . 
     If yes, step  410  is performed. If no, step  407  is performed. 
       407 : Determine whether a power of the oil pump is less than X1. 
     If yes, step  408  is performed. If no, step  4064  is performed. 
       4064 : Bypass an oil-water heat exchanger and/or reduce a water flow rate. 
     It should be noted that, these control manners may be used separately or in combination as required. 
       408 : Increase the power of the oil pump. 
     It should be noted that, in some possible implementations, the power of the oil pump may be increased by a predetermined value each time. The predetermined value may be a fixed value, or may be a value changed based on a specified condition. Step  407  may be performed again every predetermined time to determine whether an adjusted power of the oil pump is less than X1. 
       410 : Determine whether the power of the oil pump is greater than X2. 
     If yes, step  411  is performed. If no, step  4094  is performed. 
       4094 : Disable a bypass path of an oil-water heat exchanger and/or increase a water flow rate. 
       411 : Reduce the power of the oil pump. 
     It should be noted that, in some possible implementations, the power of the oil pump may be reduced by a predetermined value each time. Step  410  may be performed again every predetermined time to determine whether an adjusted power of the oil pump is greater than X2. 
     In this implementation, the controller triggers different operations based on the oil temperatures at the detection point in the oil cooling circuit, to enable the oil temperature in the oil cooling circuit to be located between the first target temperature and the second target temperature. 
     An embodiment of this disclosure further provides a controller, applied to an electric vehicle that includes an oil cooling circuit, where the oil cooling circuit flows through a motor and an inverter. The controller includes: a determining unit, configured to determine an oil temperature at a detection point, where the detection point is a specified location in the oil cooling circuit; and a processing unit, configured to: when the oil temperature is lower than a first target temperature, trigger one or more of the following operations: bypassing an oil-water heat exchanger, reducing a water flow rate, and increasing a power of an oil pump, and configured to: when the oil temperature is higher than a second target temperature, trigger one or more of the following operations: disabling a bypass path of an oil-water heat exchanger, increasing a water flow rate, and reducing a power of an oil pump. The determining unit may directly obtain the oil temperature at the detection point by using a sensor, or obtain a first specified parameter, and determine the oil temperature at the detection point based on the first specified parameter. A first specified parameter set includes one or more of the following parameters: a current of the oil pump, a rotation speed of the oil pump, a current of the motor, a rotation speed of the motor, a water flow rate, and a water temperature. The processing unit may be further configured to determine the first target temperature and the second target temperature based on a second specified parameter, where the second specified parameter includes operating scenario parameters of the electric vehicle. The operating scenario parameters of the electric vehicle include a current location of the electric vehicle, and/or a current date, and/or an operation mode of the electric vehicle, where the operation mode may include a motion mode and a normal mode. 
     Referring to  FIG.  5   , an embodiment of this disclosure provides a powertrain  500 , including a motor  501 , an inverter  502 , an oil pump  503 , an oil-water heat exchanger  504 , a water pump  505 , and a controller  506 . The inverter  502  is configured to convert a direct current into an alternating current and then transmit the alternating current to the motor  501 . The motor  501  is configured to convert the alternating current into mechanical energy to drive an electric vehicle to travel. The controller  506  is configured to control a power of the oil pump  503  and a rotation speed of the water pump  505 . The oil-water heat exchanger  504  is configured to transfer heat of an oil cooling circuit to a water cooling circuit. The controller  506  is specifically configured to perform the oil temperature control method according to any one of the embodiments in  FIG.  3 A- 1    and  FIG.  3 A- 2    to  FIG.  4 D- 1    and  FIG.  4 D- 2   . For specific details, refer to the foregoing description. Details are not described herein again. 
     Referring to  FIG.  6   , an embodiment of this disclosure further provides an electric vehicle  600 , including a power battery pack  601  and a powertrain  602 . The power battery pack  601  is configured to supply power to the powertrain  602 . The powertrain  602  is shown in  FIG.  5   . Reference is made to the foregoing description, and details are not described herein again. 
     This disclosure further provides a computer-readable storage medium, which stores a computer program. For an implementation and beneficial effects of resolving a problem by using the program, refer to implementations and beneficial effects of the oil temperature control method in  FIG.  3 A- 1    and  FIG.  3 A- 2    to  FIG.  4 D- 1    and  FIG.  4 D- 2   . No repeated description is provided. 
     An embodiment of this disclosure further provides a computer program product, where the computer program product includes a non-volatile computer-readable storage medium that stores a computer program. When the computer program is executed, a computer is enabled to perform the steps of the oil temperature control method in the embodiments corresponding to  FIG.  3 A- 1    and  FIG.  3 A- 2    to  FIG.  4 D- 1    and  FIG.  4 D- 2   . For an implementation and beneficial effects of resolving a problem by using the computer program product, refer to implementations and beneficial effects of the oil temperature control method in  FIG.  3 A- 1    and  FIG.  3 A- 2    to  FIG.  4 D- 1    and  FIG.  4 D- 2   . No repeated description is provided. 
     A person of ordinary skill in the art may understand that all or some of the processes of the methods in embodiments may be implemented by a computer program instructing relevant hardware. The program may be stored in a computer-readable storage medium. When the program runs, the processes of the methods in embodiments are performed. 
     It should be understood that, in this disclosure, “at least one (item)” means one or more, and “a plurality of” means two or more. The term “and/or” is used for describing an association relationship between associated objects, and represents that three relationships may exist. For example, “A and/or B” may represent the following three cases: Only A exists, only B exists, and both A and B exist, where A and B may be singular or plural. The character “/” usually indicates an “or” relationship between associated objects. “At least one of the following items (pieces)” or a similar expression thereof refers to any combination of these items, including any combination of singular items (pieces) or plural items (pieces). For example, at least one item (piece) of a, b, or c may indicate a, b, c, a and b, a and c, b and c, or a, b, and c, where a, b, and c may be singular or plural. 
     The apparatus embodiments described above are merely examples, and the units and modules described as separate parts may or may not be physically separate. Some or all of the units and modules may be selected based on an actual requirement to achieve the objectives of the solutions of the embodiments. A person of ordinary skill in the art may understand and implement embodiments without creative efforts. 
     The foregoing descriptions are merely specific implementations of this disclosure. It should be noted that a person of ordinary skill in the art may make several improvements or polishing without departing from the principle of this disclosure and the improvements or polishing shall fall within the protection scope of this disclosure.