Electric vehicle control device, electric drive device, and electric vehicle control method

Abstract

This electric vehicle control device comprises: an oil temperature detection unit that detects an oil temperature; a power consumption calculation unit that calculates a power consumption per unit flow rate of an electric oil pump on the basis of the power consumption and an oil flow rate per unit time of the electric oil pump; and an oil temperature adjustment unit that adjusts the state of warm-up control on the basis of the oil temperature and the power consumption per unit flow rate of the electric oil pump.

Description

Electric vehicle control device, electric drive device, and electric vehicle control method

[0001] The present invention relates to an electric vehicle control device, an electric drive device, and an electric vehicle control method that perform warm-up control.

[0002] In an electric vehicle that travels by driving a motor connected to wheels via a gear, the gear is lubricated with lubricating oil (hereinafter referred to as "oil"). Generally, oil has the property that its kinematic viscosity changes according to temperature. For example, when the oil temperature is below a predetermined temperature, the kinematic viscosity increases exponentially with a decrease in the oil temperature. Also, when the oil temperature becomes high, the amount of decrease in the kinematic viscosity with respect to an increase in the oil temperature becomes small, and the kinematic viscosity asymptotically approaches (saturates) a substantial minimum value. That is, when the oil temperature is below the predetermined temperature, the kinematic viscosity of the oil increases, increasing the rotational resistance in the gear, motor, etc. Therefore, when the oil temperature is lower than the predetermined temperature, warm-up control is performed to warm the oil by energizing the motor before starting the travel of the electric vehicle, and the travelable distance of the electric vehicle is extended.

[0003] For example, Patent Document 1 states that "an electric vehicle includes a power storage device, an electric motor, a power transmission device, a charging device, and a control device", and "when the temperature of the lubricating oil is lower than a predetermined temperature when charging the power storage device using the charging device, the control device executes warm-up control to warm the lubricating oil by rotating the electric motor when the power transmission device is in a power-off state".

[0004] JP-A-2014-117006

[0005] For example, when the temperature-kinematic viscosity characteristics of the lubricating oil change to the low-viscosity side due to contamination, deterioration, or replacement of the lubricating oil during the use of an electric vehicle, the kinematic viscosity may decrease even though the oil temperature is the same. In that case, in the technique described in Patent Document 1, warm-up control may be executed in a state where the kinematic viscosity is saturated. For this reason, the amount of electric power input to the warm-up control does not contribute to the reduction of the rotational resistance due to the warm-up control, and the travelable distance of the electric vehicle is shortened.

[0006] Conversely, if the user of an electric vehicle changes to an oil with a higher kinematic viscosity than the oil specified at the factory, even if the oil temperature is raised to a predetermined target temperature and the temperature rise control is terminated, the oil may not reach a temperature at which the kinematic viscosity saturates sufficiently. As a result, the rotational resistance in the gears and motor cannot be sufficiently reduced by the temperature rise control.

[0007] Given the above circumstances, there was a need for a method to extend the driving range of electric vehicles by appropriately raising the oil temperature, even when the oil viscosity changes.

[0008] To solve the above problems, an electric vehicle control device according to one aspect of the present invention comprises an electric drive unit and an electric oil pump for circulating oil to the electric drive unit, and is an electric vehicle control device that performs warm-up control to heat the electric drive unit and raise the temperature of the oil, comprising: an oil temperature detection unit that detects or estimates and obtains the oil temperature; a power consumption calculation unit that determines the current value flowing through the motor of the electric oil pump and the oil flow rate per unit time by the electric oil pump, and calculates the power consumption of the electric oil pump per unit flow rate based on the current value and the oil flow rate; and an oil temperature adjustment unit that adjusts the state of warm-up control based on the oil temperature and the power consumption per unit flow rate.

[0009] According to at least one aspect of the present invention, the warm-up control state is adjusted based on the oil temperature and the power consumption per unit flow rate of the electric oil pump. This allows the oil temperature to be appropriately raised even when the oil viscosity changes, thereby extending the driving range of the electric vehicle. Problems, configurations, and effects other than those described above will be clarified by the following description of embodiments for carrying out the invention.

[0010] This figure shows an example of the configuration of an electric vehicle controlled by an electric vehicle control device according to one embodiment of the present invention and an example of the cooling system circuit. This figure shows an example of the hardware configuration of an integrated ECU according to one embodiment of the present invention. This block diagram shows an example of the functional configuration of the arithmetic unit of a control device according to one embodiment of the present invention. This is a flowchart of electric vehicle control according to one embodiment of the present invention. This is a subroutine flowchart showing the processing of steps S1301 to S1310 of the electric vehicle control shown in Figure 4. This is a subroutine flowchart showing the processing of steps S1401 to S1410 of the electric vehicle control shown in Figure 4. This is a subroutine flowchart showing the processing of steps S1601 to S1610 of the electric vehicle control shown in Figure 4. This is a subroutine flowchart showing the processing of steps S901 to S910 of the electric vehicle control shown in Figure 4. This figure shows an example of the kinematic viscosity characteristics with respect to oil temperature. This figure shows the difference in gear loss when stop-time warm-up control is implemented and when stop-time warm-up control is not implemented according to one embodiment of the present invention. This figure shows the difference in power consumption during WLTC driving when stop-time warm-up control is implemented and when stop-time warm-up control is not implemented according to one embodiment of the present invention. This figure shows examples of the kinematic viscosity characteristics with respect to oil temperature for high viscosity oil and low viscosity oil, respectively. This figure shows the difference in gear loss when learning oil temperature acquisition is performed and when learning oil temperature acquisition is not performed, according to one embodiment of the present invention. This figure shows the difference in electric power consumption during WLTC driving when learning oil temperature acquisition is performed and when learning oil temperature acquisition is not performed, according to one embodiment of the present invention. This figure shows the difference in gear loss when warm-up control is performed and when warm-up control is not performed, according to one embodiment of the present invention.

[0011] Hereinafter, examples of embodiments for carrying out the present invention (hereinafter referred to as "embodiments") will be described with reference to the accompanying drawings. In this specification and the accompanying drawings, common or similar components are assigned the same reference numeral, and redundant descriptions are omitted. Furthermore, if there are multiple identical or similar components, different subscripts may be assigned to the same reference numeral in the description. However, if it is not necessary to distinguish between these multiple components, the subscript may be omitted in the description. Unless otherwise specified, the number of each component may be singular or plural.

[0012] The electric vehicle control device of the present invention is applicable, for example, to an in-vehicle ECU (Electronic Control Unit) for an Advanced Driver Assistance System (ADAS) or Autonomous Driving (AD). Alternatively, the present invention is applicable to a control device that can communicate with an in-vehicle ECU for AD or AD.

[0013] First, an overview of the electric vehicle controlled by the electric vehicle control device according to one embodiment of the present invention will be described with reference to Figure 1. Figure 1 is a diagram showing the configuration of the electric vehicle 1 controlled by the electric vehicle control device and an example of the cooling system circuit. Figure 1 shows an integrated ECU 9 equipped with input and output of various sensor signals and control signals of the electric vehicle 1, and a cooling system circuit using coolant and oil.

[0014] The electric vehicle 1 is a vehicle (for example, an electric car) whose wheels are driven by a traction motor. The motor 22 is an electric motor that operates on power supplied from a high-voltage battery 4, and in this embodiment, it is a three-phase motor having three phases of UVW (see Figure 1). The electric vehicle 1 is equipped with an electromechanical integrated electric drive unit 2 as a power unit, which has an inverter 21, a motor 22, a gearbox 23, and an electric oil pump 24. The motor 22 is an oil-cooled type (indicated as "oil-cooled motor" in the figure) that cools the coil with oil. The electric drive unit 2 shown in Figure 1 is also called, for example, "eAxle". Note that the electric drive unit 2 may also be configured without a built-in electric oil pump 24.

[0015] The motor 22 and gearbox 23 are examples of an electric drive system. In this embodiment, the electric drive system includes at least the motor 22 and gearbox 23. The electric drive unit 2, which includes an inverter 21 that supplies power to the motor 22, is an example of a heat-generating device. The present invention can be applied to an electric drive unit 2 incorporating such an electric drive system to appropriately raise the oil temperature and extend the driving range of an electric vehicle.

[0016] The motor 22 and the gears of the gearbox 23 are meshed so that the rotational torque generated by the motor 22 is transmitted to the axle via the gears. For example, the gearbox 23 can be configured as a three-axis gear mechanism (not shown). The three-axis gear mechanism consists of an input shaft and input gear to which the rotation of the motor 22 is input, an output shaft and output gear connected to the axle, and an intermediate gear and intermediate shaft interposed between the input gear and the output gear, and the reduction ratio, which is the ratio of the input shaft rotation speed to the output shaft rotation speed, is set to a predetermined value (for example, 10). The three-axis gear mechanism is lubricated with oil supplied from an oil pan (not shown), as will be described later, and the oil shares the function of both a gear lubricant and a motor 22 coolant.

[0017] The oil in the oil pan is pumped up by an electric oil pump 24. The oil is pumped up to the top of the motor 22 via an oil pipe 26, and an oil cooler 25 is provided along the way as a heat exchanger capable of exchanging heat with cooling water. In this embodiment, an oil flow sensor 28 is attached to the oil pipe 26 connecting the electric oil pump 24 and the oil cooler 25. The oil flow sensor 28 measures the flow rate of oil flowing through the oil pipe 26. For example, the oil flow sensor 28 can be a so-called impeller-type sensor that detects the rotation speed of an impeller immersed in the oil flowing through the oil pipe 26.

[0018] The oil flow rate can also be estimated by detecting the motor rotation speed of the electric oil pump 24, the current flowing through the motor of the electric oil pump 24, and the power supply voltage (low-voltage battery voltage) supplied to the electric oil pump 24. Therefore, for example, an electromechanical integrated oil pump control unit (not shown) capable of detecting the motor rotation speed of the electric oil pump 24 can be installed inside the electric oil pump 24, and this oil pump control unit can be used as an oil flow rate sensor 28. An outlet for the oil piping 26 is provided inside the motor 22 so that the oil pumped up to the top of the motor 22 is discharged toward the coils of the motor 22. After the oil has cooled the coils of the motor 22, it reaches the bottom of the motor 22 and drips into the gearbox 23 via the oil piping 26, lubricates the three-axis gear mechanism inside the gearbox 23, and returns to the oil pan.

[0019] The cooling water is circulated by an electric cooling water pump 7 (labeled "electric cooling water pump" in the diagram). The inverter 21 is water-cooled. Inside the inverter 21, a cooling water channel is provided to cool the heat generated from the power semiconductors used as inverter elements. The cooling water piping 8 that forms the cooling water channel circulates the cooling water to cool each component in the following order: inverter 21, oil cooler 25, radiator 3, high-voltage battery 4, charger 5, and DC / DC converter 6.

[0020] In this embodiment, a cooling water flow sensor 71 is attached to the cooling water pump 7 or the cooling water piping 8 connected to the cooling water pump 7. The cooling water flow sensor 71 measures the flow rate of cooling water flowing through the cooling water piping 8. For example, the cooling water flow sensor 71 can be an impeller-type sensor that detects the rotation speed of an impeller placed in the cooling water piping 8. The cooling water flow rate can also be estimated by detecting the rotation speed of the pump impeller of the cooling water pump 7, the current flowing to the motor of the cooling water pump 7, and the power supply voltage (low-voltage battery voltage) supplied to the cooling water pump 7. Therefore, for example, a mechatronic integrated cooling water pump control unit (not shown) capable of detecting the rotation speed of the impeller of the cooling water pump 7 and the amount of current flowing to the motor of the cooling water pump 7 can be placed inside the cooling water pump 7, and this cooling water pump control unit can be used as the cooling water flow sensor 71.

[0021] The oil piping 26 connected to the oil cooler 25 is equipped with a first switching valve 81 and a bypass passage 8b-1 so that the oil can bypass the oil cooler 25. The gearbox 23 is also fitted with an oil temperature sensor 27 that measures the temperature of the oil supplied to the gearbox 23. The first switching valve 81 switches to the side that bypasses the oil cooler 25 when the oil temperature measured by the oil temperature sensor 27 is lower than a predetermined value. This allows the oil to flow into the bypass passage 8b-1, preventing heat exchange between the oil and coolant and thus preventing the oil temperature from dropping. On the other hand, if the oil temperature is higher than a predetermined value, for example, 60 degC, the first switching valve 81 switches to the side where the oil and coolant exchange heat to cool the oil.

[0022] The integrated ECU 9 may detect the oil temperature based on the sensor signal output by the oil temperature sensor 27, as described above, or it may estimate the oil temperature from the sensor signals of one or more other sensors. For example, a machine learning model that takes one or more other sensor signals as input and outputs the oil temperature may be used to estimate the oil temperature.

[0023] The coolant piping 8 connected to the radiator 3 is equipped with a second switching valve 82 and a bypass passage 8b-2 so that the coolant can bypass the radiator 3. The second switching valve 82 switches to the bypass side of the radiator 3 when the coolant temperature of the coolant temperature sensor 31 installed downstream of the radiator 3 is lower than a predetermined value. This controls the flow of coolant to the bypass passage 8b-2, preventing the coolant from radiating heat from the radiator 3. On the other hand, when the coolant temperature is higher than a predetermined value, the second switching valve 82 switches to the side where the coolant flows to the radiator 3, lowering the coolant temperature by radiating heat from the radiator 3 to the atmosphere.

[0024] The high-voltage battery 4 supplies high-voltage direct current (DC) power to the inverter 21 and the DC / DC converter 6. The inverter 21 is a DC / AC converter that converts high-voltage direct current (DC) to alternating current (AC) and supplies it to the motor 22. The DC / DC converter 6 converts the high-voltage direct current (DC) power to, for example, 12-volt direct current (12VDC) and supplies power to the various devices inside or outside the electric drive unit 2, excluding the motor 22. The high-voltage battery 4 is equipped with a battery temperature sensor 41 that measures the cell temperature of the high-voltage battery 4. Alternatively, the 12-volt direct current power from the DC / DC converter 6 may be used to charge a low-voltage battery (not shown), and direct current (12VDC) power may be supplied from the low-voltage battery to the various devices inside or outside the electric drive unit 2.

[0025] The control described above is performed by the integrated ECU 9. The integrated ECU 9 receives signals such as oil temperature, oil flow rate (oil pump rotation speed, current consumption of electric oil pump 24), coolant temperature, coolant flow rate (coolant pump rotation speed, current consumption of coolant pump 7), voltage and temperature of high-voltage battery 4, output voltage of DC / DC converter 6 (voltage of low-voltage battery), current of inverter 21 (current to the UVW phases of motor 22), and rotation speed of motor 22. The integrated ECU 9 also receives a signal of the current ambient temperature measured by an ambient temperature sensor (not shown).

[0026] The integrated ECU 9 then performs calculations based on the input signals and outputs various control signals (commands) from the calculation results. The integrated ECU 9 outputs signals such as the target rotational speed of the electric oil pump 24, the target rotational speed of the cooling water pump 7, the operation settings of the inverter 21 (d-axis current value and q-axis current value for the vector control of the motor 22, and the target rotational speed of the motor 22), the opening and closing command for the first switching valve 81, and the opening and closing command for the second switching valve 82. The current to the UVW phases of the motor 22, the opening and closing of the first switching valve 81 and the second switching valve 82, the rotational speed of the electric oil pump 24, and the rotational speed of the cooling water pump 7 are controlled by the various control signals output from the integrated ECU 9.

[0027] Next, the hardware configuration of the integrated ECU 9 according to one embodiment of the present invention will be described with reference to Figure 2.

[0028] Figure 2 is a diagram showing an example of the hardware configuration of an integrated ECU 9 according to one embodiment of the present invention. The integrated ECU 9 comprises an input unit 91, a control unit 92, and an output unit 93. The input unit 91 is an interface for processing the input of sensor signals. The control unit 92 is a device that controls the entire integrated ECU 9. The input unit 91 is an interface for processing the output of control signals.

[0029] The input unit 91 receives, for example, a coolant temperature signal, an oil temperature signal, a battery temperature signal, an inverter current signal, a high-voltage battery voltage signal, a motor rotation speed signal, a coolant flow rate signal (coolant pump rotation speed, current consumption of the coolant pump 7), and an oil flow rate signal (oil pump rotation speed, current consumption of the electric oil pump 24), and a DC-DC output voltage signal (low-voltage battery voltage signal). The input unit 91 also receives an ambient temperature signal. The motor rotation speed can be detected, for example, by processing the signal from a rotation angle sensor (resolver) (not shown) provided on the motor 22 using the inverter 21.

[0030] The output unit 93 outputs control signals for, for example, the target rotational speed of the cooling water pump, the target rotational speed of the oil pump, inverter operation settings (d-axis current value and q-axis current value for the vector control of the motor 22, and the target rotational speed of the motor 22), opening / closing of the first switching valve, and opening / closing of the second switching valve. Here, only the input sensor signals and output control signals related to this embodiment are described, and there are other input sensor signals and output control signals other than those shown in Figure 2.

[0031] The control device 92 includes an arithmetic unit 921, a ROM (Read Only Memory) 922, a RAM (Random Access Memory) 923, and a learning result storage unit 924. Based on sensor signals input from the input unit 91, calculations are performed in the arithmetic unit 921, and control signals are generated from the calculation results in the arithmetic unit 921. The control signals are output to each device by the output unit 93. The arithmetic unit 921 is a processor such as a CPU (Central Processing Unit) or an MPU (Micro Processing Unit). The arithmetic unit 921 performs calculations based on input signals and outputs control signals to each device from the output unit 93 based on the calculation results.

[0032] ROM 922 stores various map data that are referenced based on input sensor signals. For example, ROM 922 stores various setting values ​​for the vector control of the motor 22, various setting values ​​for the warm-up control when stopped, and various setting values ​​for the warm-up control when running. Calculation results generated during the calculation processing of the arithmetic unit 921 are recorded in RAM 923. In this embodiment, as will be described later, a warm-up control function is provided that energizes the inverter 21 when the gear oil temperature is low. The arithmetic unit 921 includes a learning result storage unit 924 that records an oil temperature threshold (learned oil temperature) for determining whether to turn this warm-up control on or off. Non-volatile memory is used for the learning result storage unit 924.

[0033] Furthermore, the ROM 922 or non-volatile memory stores program code for the software that implements the electric vehicle control according to this embodiment. The arithmetic unit 921 executes the program code read from the ROM 922 or non-volatile memory, thereby realizing the functions of each functional block of the arithmetic unit 921 shown in Figure 3, which will be described later.

[0034] When the electric vehicle 1 is driven by the motor 22, the inverter 21 sets the d-axis current value and q-axis current value of the motor's vector control based on the target rotational speed, required drive torque, and warm-up energization command of the motor 22 output from the integrated ECU 9, and supplies current to the UVW phase (see Figure 1) of the motor 22. In this way, the inverter 21 forms a rotating magnetic field in the coil, causing the motor 22 to rotate at the target rotational speed while generating a rotational torque that matches the required drive torque.

[0035] In this embodiment, the motor 22 is equipped with a motor rotation angle sensor for detecting the rotation angle of the rotor. The inverter 21 acquires the rotation angle of the motor rotor detected by the motor rotation angle sensor, as well as the target rotation speed, required drive torque, and warm-up energization command for the motor 22 input from the control device 92. Based on this acquired information, the inverter 21 sets the d-axis current value and q-axis current value for the motor's vector control and controls the timing of the three-phase AC waveform and the amount of energized current supplied to the UVW phases. For example, during normal operation, the inverter 21 sets the d-axis current value and q-axis current value based on a data table (map) that is set in advance to correspond to the rotation angle of the motor 22's rotor, target rotation speed, and required drive torque, so that the efficiency of the motor 22 is appropriate experimentally or theoretically. In this way, the inverter 21 controls the rotation speed and torque of the motor 22 during normal operation.

[0036] In this embodiment, in addition to the normal vector control (normal control mode) which drives the motor 22 to ensure proper efficiency, there are two motor drive modes. One is the running warm-up control mode. In the running warm-up control mode, the inverter 21 sets the q-axis current value according to the required drive torque necessary for vehicle operation, and also sets the d-axis current value in cooperation with the q-axis current value to promote the warm-up operation of the motor 22, thereby driving the motor 22 and driving the electric vehicle 1. This makes it possible to increase the input power by increasing the d-axis current value while satisfying the target rotational speed and required drive torque of the motor 22. As a result, the inverter 21 and the rotor and stator of the motor 22 can generate more heat than in normal operation.

[0037] Another mode is the stop-time warm-up control mode. In the stop-time warm-up control mode, the inverter 21 sets a q-axis current value that does not generate driving torque in the motor 22, and also sets a d-axis current value that works in cooperation with the q-axis current value to promote the warm-up operation of the motor 22. This allows heat to be generated in the inverter 21 and the rotor or stator of the motor 22 when the motor 22 is stopped.

[0038] In this embodiment, the electric drive unit 2 is configured to use the same oil for cooling the coils of the motor 22 and lubricating the gears. The electric drive unit 2 can preheat the oil by supplying power to the motor 22 from the inverter 21 before starting to drive using the stop-time warm-up control mode. In this embodiment, the stop-time warm-up control mode or the driving-time warm-up control mode is used to adjust the stop-time warm-up control or the driving-time warm-up control so that the decrease in power consumption due to the reduction in oil friction loss during driving caused by warming the oil is greater than the increase in power consumption due to warming the oil at low temperatures. This embodiment reduces the total power consumption by adjusting the stop-time warm-up control or the driving-time warm-up control, thereby extending the driving range of the electric vehicle 1.

[0039] Under conditions where the oil temperature is lower than the learned oil temperature described later and the kinematic viscosity of the oil is high, the power loss due to oil friction when the vehicle is running is greater than the power consumption consumed by using the stop-time warm-up control mode or the running-time warm-up control mode. Conversely, under conditions where the oil temperature is above the learned oil temperature described later and the kinematic viscosity of the oil is low, the power loss due to oil friction when the vehicle is running is less than or equal to the power consumption consumed by using the stop-time warm-up control mode or the running-time warm-up control mode. Therefore, this embodiment monitors the oil temperature and selects and adjusts the stop-time warm-up control mode, the running-time warm-up control mode, and the normal control mode based on the learned oil temperature described later, thereby reducing the power consumption of the electric vehicle 1 when it is running.

[0040] Incidentally, the kinematic viscosity of oil changes due to normal wear and tear and aging during the vehicle's use. Furthermore, when a user changes the oil during the vehicle's use, the oil may have different kinematic viscosity characteristics than the previous oil. In such cases, where the kinematic viscosity characteristics of the oil change during the vehicle's use, a predetermined threshold temperature may no longer be sufficient.

[0041] For example, if the kinematic viscosity of the oil changes due to normal wear to a state lower than that of new oil, the optimal threshold temperature will fall below a predetermined threshold temperature based on the kinematic viscosity of new oil. In other words, the power loss due to oil friction when the vehicle is running with an oil temperature lower than a predetermined threshold temperature will be less than or equal to the power consumption by using the stop-time warm-up control mode or the running warm-up control mode. Therefore, warm-up control based on a predetermined threshold temperature will overheat the oil that has changed to a state with low kinematic viscosity due to normal wear, resulting in a deterioration of energy efficiency.

[0042] Conversely, when the oil is changed to an oil with a kinematic viscosity greater than that before the change, the optimal threshold temperature increases from a certain fixed threshold temperature determined in advance based on the kinematic viscosity of the new oil. That is, the power loss due to oil friction when the vehicle is running at an oil temperature higher than a certain fixed threshold temperature determined in advance exceeds the power consumption consumed by using the warm-up control mode during stop or the warm-up control mode during running. Therefore, in the warm-up control based on a certain fixed threshold temperature determined in advance, the heating of the oil is insufficient, the oil friction at the start of running is large, and the electricity cost deteriorates.

[0043] Therefore, in the control device 92 according to the present embodiment, in the warm-up control during stop or the warm-up control during running, when the motor 22 is energized, the electric oil pump 24 is also operated, and the oil flow rate is obtained from the sensor signal of the oil flow rate sensor 28 or the rotation speed of the oil pump. Then, the control device 92 uses an oil pump power consumption calculation unit 111 described later to calculate the power consumption of the electric oil pump 24 per unit oil flow rate from the oil pump current value flowing through the motor of the electric oil pump 24 and the voltage value of the low-voltage battery that is the operating power source of the electric oil pump 24. Further, the control device 92 obtains the change amount per unit time of the power consumption of the electric oil pump 24 every predetermined time (for example, every second), or the first derivative value obtained by differentiating the power consumption of the electric oil pump 24 once with respect to time. Then, the control device 92 stops the warm-up control mode during stop or the warm-up control mode during running at the timing when the value based on the change amount per unit time of the oil pump power consumption or the first derivative value becomes less than or equal to a predetermined value, and records the oil temperature at this time as the learned oil temperature. Thereby, a learned oil temperature corresponding to the change in the kinematic viscosity characteristics of the oil can be obtained.

[0044] Next, the function of the arithmetic device 921 of the control device 92 according to an embodiment of the present invention will be described with reference to FIG. 3. FIG. 3 is a block diagram showing a functional configuration example of the arithmetic device 921 of the control device 92 according to an embodiment of the present invention. The arithmetic device 921 includes a plurality of determination units and calculation units necessary for controlling the electric vehicle 1. The main functions of each determination unit and calculation unit will be described.

[0045] The warm-up on / off control determination unit 101 has a function of determining on or off of the warm-up control from the learned oil temperature and the current oil temperature. Further, the warm-up on / off control determination unit 101 has a function of determining the end timing of the warm-up control from the value of the power consumption of the electric oil pump 24. Further, the warm-up on / off control determination unit 101 controls the switching from off to on or from on to off of the warm-up control. Further, the warm-up on / off control determination unit 101 executes the control in the selected control mode. Further, the warm-up on / off control determination unit 101 performs processing and calculation on the input / output of the arithmetic unit 921 during warm-up on and during warm-up off.

[0046] The warm-up control mode determination unit 102 has a function of selecting the control mode of the motor 22 from the stop-time warm-up control mode, the running-time warm-up control mode, or the normal control mode.

[0047] The switching valve opening / closing determination unit 109 has a function of determining the opening and closing of the first switching valve 81 and the second switching valve 82 from the coolant temperature and the oil temperature.

[0048] The oil pump power consumption calculation unit 111 has a function of calculating the power consumption of the electric oil pump 24 per unit oil flow rate from the oil pump current value flowing through the electric motor (oil pump motor) in the electric oil pump 24 and the voltage value of the low-voltage battery which is the operating power source of the electric oil pump 24. The oil pump current value can be obtained by an oil pump motor control unit (not shown) provided inside the electric oil pump 24 together with the oil pump motor rotation speed. The oil pump current value and the oil pump rotation speed obtained by the oil pump motor control unit can be obtained from the oil pump motor control unit of the electric oil pump 24 to the arithmetic unit 921 via a well-known communication means. As the communication means, for example, SENT (Single Edge Nibble Transmission) communication or CAN (Controller Area Network) communication can be used.

[0049] Next, the electric vehicle control by the control device 92 before or after the electric vehicle 1 starts running in one embodiment of the present invention will be described with reference to FIGS. 4 to 8.

[0050] Figure 4 is a flowchart showing an example of a procedure for controlling an electric vehicle in which a stop-time warm-up control mode, a driving-time warm-up control mode, or a normal control mode is selected according to one embodiment of the present invention. First, the warm-up on / off control determination unit 101 of the calculation unit 921 determines whether or not the power switch of the electric vehicle 1 is in the "power on" state (S0).

[0051] In this context, the power switch is a contact-type or contactless push switch located on the vehicle body that emits a switch operation signal in response to a driver's press. However, a remote control switch that transmits a switch operation signal from outside the vehicle using radio waves or the like can also be used as the power switch. The warm-up on / off control determination unit 101 is configured, for example, using a flip-flop, and determines "power on" and "power off" according to the input switch operation signal. For example, the warm-up on / off control determination unit 101 determines "power on" when a switch operation signal is input from a push switch or remote control switch while the initial state is "power off," or it determines "power off" when a switch operation signal is input from a push switch or remote control switch while the "power on" state is "power on."

[0052] Next, the warm-up on / off control determination unit 101 detects the current oil temperature using the oil temperature sensor 27. The warm-up on / off control determination unit 101 also detects the current coolant temperature using the coolant temperature sensor 31. Furthermore, the warm-up on / off control determination unit 101 detects the current ambient temperature using an ambient temperature sensor (not shown).

[0053] Next, the warm-up on / off control determination unit 101 determines whether the current oil temperature is higher than the current ambient temperature (S2) if the electric vehicle 1 is "power off" (NO in S1). If it determines that the current oil temperature is less than or equal to the current ambient temperature (NO in S2), it indicates that the electric vehicle 1 is parked and the heat from the oil has been dissipated into the outside air, so the learning flag F_TOILADPT is reset to zero (S2a).

[0054] Next, if step S2 determines that the current oil temperature is higher than the current ambient temperature (YES in S2), or after processing in step S2a, the warm-up on / off control determination unit 101 resets the warm-up control execution count CTWUP to zero (S3). The warm-up on / off control determination unit 101 also stops the power supply to the motor 22 and the electric oil pump 24 as part of the parking control mode. Furthermore, it resets the control mode "MODE" to #0 (S4).

[0055] In step S1, if the electric vehicle 1 is "powered on" (YES in S1), the rotational speed of the motor 22, the target rotational speed of the motor 22, and the requested drive torque are read into the calculation unit 921 (S5).

[0056] After the processing in step S5, the warm-up on / off control determination unit 101 detects the oil flow rate per unit time using the oil flow rate sensor 28 (S6).

[0057] Next, the oil pump power consumption calculation unit 111 calculates the power consumption of the electric oil pump 24 per unit flow rate (S7). The power consumption of the electric oil pump 24 per unit time can be calculated from the oil pump current value flowing to the motor of the electric oil pump 24 and the voltage value of the low-voltage battery which is the operating power source for the electric oil pump 24. Furthermore, the power consumption of the electric oil pump 24 per unit flow rate can be calculated using the oil pump current value, the voltage value of the low-voltage battery, and the oil flow rate per unit time as described above.

[0058] Next, the oil pump power consumption calculation unit 111 calculates the derivative value of oil pump power consumption by differentiating the power consumption per unit flow rate of the electric oil pump 24 once with respect to time (S8). As an approximation of the derivative value of oil pump power consumption, the change in oil pump power consumption, which is the amount of change in the power consumption per unit flow rate of the electric oil pump 24 per unit time, can also be used.

[0059] Next, the warm-up on / off control determination unit 101 acquires the learned oil temperature (S9). The learned oil temperature is a temperature threshold that switches whether or not to perform warm-up control while stopped or warm-up control while driving instead of the normal control mode. Details of the process in step S9 will be explained later with reference to Figure 8.

[0060] Next, the warm-up on / off control determination unit 101 determines whether the learning flag F_TOILADPT is 1 or not (S10). If the learning flag F_TOILADPT is "1" (YES in S10), the warm-up on / off control determination unit 101 determines whether the oil temperature detected in step S0 is greater than the learned oil temperature (S15). If the learning flag F_TOILADPT is 1, the learned oil temperature has already been acquired.

[0061] If the learning flag F_TOILADPT is zero (NO in S10), or if the detected oil temperature is below the learned oil temperature (NO in S15), the oil needs to be heated. Therefore, the warm-up control mode determination unit 102 determines whether the rotational speed of the motor 22 is greater than 0 [r / min] (S11), and whether the target rotational speed of the motor 22 is greater than 0 [r / min] (S12).

[0062] The warm-up control mode determination unit 102 determines that the rotational speed of the motor 22 is 0 [r / min] or less (NO in S11) and that the target rotational speed of the motor 22 is 0 [r / min] or less (NO in S12), that is, when the electric vehicle 1 is stopped, it selects the stop-time warm-up control mode (S13). Then, the warm-up on / off control determination unit 101 sets MODE to #1 after executing the stop-time warm-up control mode subroutine (S13). The details of the process in step S13 will be explained later with reference to Figure 5.

[0063] On the other hand, if the warm-up control mode determination unit 102 determines that the motor rotation speed is greater than 0 [r / min] (YES in S11) or the target motor rotation speed is greater than 0 [r / min] (YES in S12), that is, if the electric vehicle 1 is running or has requested to run, it selects the running warm-up control mode (S14). Then, the warm-up on / off control determination unit 101 sets MODE to #2 after executing the running warm-up control mode subroutine (S14). Details of the process in step S14 will be explained later with reference to Figure 6.

[0064] The warm-up control mode determination unit 102 determines that the learning flag F_TOILADPT is "1" (YES in S10) and that the current oil temperature is greater than the learned oil temperature (YES in S15), and selects the normal control mode (S16). Then, the warm-up on / off control determination unit 101 executes the subroutine for the normal control mode and sets MODE to #3 (S16). Details of the process in step S16 will be explained later with reference to Figure 7.

[0065] After processing in step S4, step S13, step S14, or step S16, the arithmetic unit 921 returns to step S0 and repeats the electric vehicle control process described above. That is, the arithmetic unit 921 periodically repeats the electric vehicle control process described above as long as power is supplied.

[0066] Next, the process of the stop-time warm-up control (S13) according to one embodiment of the present invention will be described with reference to Figure 5. Figure 5 is a flowchart showing an example of the stop-time warm-up control procedure according to one embodiment of the present invention. When the stop-time warm-up control mode for when the vehicle is not moving is selected according to the flowchart shown in Figure 4, the control device 92 operates according to the flowchart shown in Figure 5.

[0067] First, the warm-up on / off control determination unit 101 determines whether the warm-up control execution count CTWUP is less than the warm-up control execution count setting value #CTWUP (S1301). If the execution count CTWUP is less than the setting value #CTWUP (YES in S1301), the warm-up on / off control determination unit 101 determines whether the MODE is #1 (S1302). If the MODE is #1 (YES in S1302), the stop-time warm-up control (S13) process has already started, and the process proceeds to step S1304.

[0068] If MODE is not #1 (NO in S1302), it indicates that it is time to start the warm-up control process during shutdown (S13), so the warm-up on / off control determination unit 101 increments the execution count CTWUP (S1303).

[0069] Next, if MODE is #1 (YES in S1302), or after processing in step S1303, the warm-up on / off control determination unit 101 accesses ROM 922 to set the d-axis current value and q-axis current value of the motor 22's vector control as inverter operation settings in the warm-up control when stopped. Furthermore, the warm-up on / off control determination unit 101 accesses ROM 922 to set the oil pump rotation speed (oil pump target rotation speed) for the warm-up control when stopped (S1304).

[0070] In step S1301, if the execution count CTWUP is greater than or equal to the set value #CTWUP (NO in S1301), it indicates that the predetermined number of warm-up control cycles has been completed. Here, the warm-up on / off control determination unit 101 sets the d-axis current value and q-axis current value for the vector control of the motor 22, similar to the inverter operation setting in the normal control mode (S16) described later. Furthermore, the warm-up on / off control determination unit 101 accesses the ROM 922 to set the oil pump rotation speed (oil pump target rotation speed) for normal control (S1305).

[0071] After the processing in step S1304 or step S1305 described above, the warm-up on / off control determination unit 101 transmits the target rotational speed of the oil pump to the oil pump control unit (not shown) of the electric oil pump 24. The oil pump control unit of the electric oil pump 24 controls the energization of the electric oil pump 24 based on the target rotational speed of the oil pump (S1306).

[0072] Next, the warm-up on / off control determination unit 101 transmits the inverter operation settings to the inverter 21. The inverter 21 then energizes the motor 22 based on the inverter operation setting values ​​(d-axis current value and q-axis current value) (S1307).

[0073] Next, the switching valve opening / closing determination unit 109 determines whether the coolant temperature detected in step S0 (Figure 4) above is greater than the oil temperature (S1308). If the coolant temperature is less than or equal to the oil temperature (NO in S1308), the first switching valve 81 is set to "closed" to prevent heat from being released from the oil to the coolant (S1309). When the first switching valve 81 is "closed", the system switches to the bypass passage 8b-1, which does not allow the coolant to flow to the oil cooler 25. If the coolant temperature is greater than the oil temperature (YES in S1308), the first switching valve 81 is set to "open" (S1310). When the first switching valve 81 is "open", the coolant flows to the oil cooler 25, and heat is absorbed from the coolant into the oil, accelerating the rise in oil temperature.

[0074] After the processing in step S1309 or S1310 in Figure 5, the process returns to the flowchart shown in Figure 4, and the processing (S0 to S16) in the flowchart of Figure 4 is repeated.

[0075] Next, the process of the on-road warm-up control (S14) according to one embodiment of the present invention will be described with reference to Figure 6. Figure 6 is a flowchart showing an example of the on-road warm-up control procedure according to one embodiment of the present invention. When the on-road warm-up control mode (S14) for when the vehicle is running is selected according to the flowchart shown in Figure 4, the control device 92 operates according to the flowchart shown in Figure 6.

[0076] First, the warm-up on / off control determination unit 101 determines whether the warm-up control execution count CTWUP is less than the warm-up control execution count setting value #CTWUP (S1401). If the execution count CTWUP is less than the setting value #CTWUP (YES in S1401), the warm-up on / off control determination unit 101 determines whether the MODE is #2 (S1402). If the MODE is #2 (YES in S1302), the warm-up control during driving (S14) process has already started, and the process proceeds to step S1404.

[0077] If MODE is not #2 (NO in S1402), it indicates that it is time to start the warm-up control process during driving (S14), so the warm-up on / off control determination unit 101 increments the execution count CTWUP (S1403).

[0078] Next, if MODE is #2 (YES in S1402), or after processing in step S1403, the warm-up on / off control determination unit 101 accesses ROM 922 to set the d-axis current value and q-axis current value of the motor 22's vector control as inverter operation settings for warm-up control during driving. Furthermore, the warm-up on / off control determination unit 101 accesses ROM 922 to set the oil pump rotation speed (oil pump target rotation speed) for warm-up control during driving (S1404).

[0079] In step S1401, if the execution count CTWUP is greater than or equal to the set value #CTWUP (NO in S1401), it indicates that the predetermined number of warm-up control cycles has been completed. Here, the warm-up on / off control determination unit 101 sets the d-axis current value and q-axis current value for the vector control of the motor 22, similar to the inverter operation setting in the normal control mode (S16) described later. Furthermore, the warm-up on / off control determination unit 101 accesses the ROM 922 to set the oil pump rotation speed (oil pump target rotation speed) for normal control (S1405).

[0080] After the processing in step S1404 or step S1405 described above, the warm-up on / off control determination unit 101 transmits the target rotational speed of the oil pump to the oil pump control unit (not shown) of the electric oil pump 24. The oil pump control unit of the electric oil pump 24 controls the energization of the electric oil pump 24 based on the target rotational speed of the oil pump (S1406).

[0081] Next, the warm-up on / off control determination unit 101 transmits the inverter operation settings to the inverter 21. The inverter 21 then energizes the motor 22 based on the inverter operation setting values ​​(d-axis current value and q-axis current value) (S1407).

[0082] Next, the switching valve opening / closing determination unit 109 determines whether the coolant temperature detected in step S0 (Figure 4) above is greater than the oil temperature (S1408). If the coolant temperature is less than or equal to the oil temperature (NO in S1408), the switching valve opening / closing determination unit 109 sets the first switching valve 81 to "closed" to prevent heat from being released from the oil to the coolant (S1409). When the first switching valve 81 is "closed", the system switches to the bypass flow path 8b-1, which does not allow the coolant to flow to the oil cooler 25. If the coolant temperature is greater than the oil temperature (YES in S1408), the switching valve opening / closing determination unit 109 sets the first switching valve 81 to "open" (S1410). When the first switching valve 81 is "open", the coolant flows to the oil cooler 25, and heat is absorbed from the coolant into the oil, accelerating the rise in oil temperature.

[0083] After the completion of step S1409 or S1410 in Figure 6, the process returns to the flowchart shown in Figure 4, and the steps (S0 to S16) of the flowchart in Figure 4 are repeated.

[0084] Next, the processing of the normal control mode (S16) according to one embodiment of the present invention will be described with reference to Figure 7. Figure 7 is a flowchart showing an example of the normal control procedure according to one embodiment of the present invention. When the normal control mode is selected according to the flowchart shown in Figure 4, the control device 92 operates according to the flowchart shown in Figure 7.

[0085] In normal control mode, the warm-up on / off control determination unit 101 first sets the d-axis current value and q-axis current value of the motor 22's vector control as inverter operation settings (S1601).

[0086] Next, the warm-up on / off control determination unit 101 accesses the ROM 922 to set the normal control oil pump rotation speed (oil pump target rotation speed) (S1602).

[0087] Next, the warm-up on / off control determination unit 101 transmits the target rotational speed of the oil pump to the oil pump control unit (not shown) of the electric oil pump 24. The oil pump control unit of the electric oil pump 24 controls the power supply to the electric oil pump 24 based on the target rotational speed (S1603).

[0088] Next, the warm-up on / off control determination unit 101 transmits the inverter operation settings to the inverter 21. The inverter 21 then energizes the motor 22 based on the inverter operation setting values ​​(d-axis current value and q-axis current value) obtained in step S1601 (S1604).

[0089] Next, the switching valve opening / closing determination unit 109 determines whether the oil temperature detected in step S0 (Figure 4) is, for example, less than 60 degrees Celsius (S1605). If the oil temperature is less than 60 degrees Celsius (YES in S1605), the switching valve opening / closing determination unit 109 sets the first switching valve 81 to "closed" to prevent heat from being dissipated from the oil to the coolant (S1606). When the first switching valve 81 is "closed", the system switches to the bypass passage 8b-1, which does not allow coolant to flow to the oil cooler 25. If the oil temperature is 60 degrees Celsius or higher (NO in S1605), the switching valve opening / closing determination unit 109 sets the first switching valve 81 to "open" to terminate the oil temperature rise (S1607). When the first switching valve 81 is "open", the system switches to the coolant passage, which allows coolant to flow to the oil cooler 25, and heat is dissipated from the oil to the coolant.

[0090] Next, after processing in step S1606 or S1607, the switching valve opening / closing determination unit 109 determines whether the coolant temperature detected in step S0 (Figure 4) is, for example, less than 20 degrees Celsius (S1608). If the coolant temperature is less than 20 degrees Celsius (YES in S1608), the switching valve opening / closing determination unit 109 sets the second switching valve 82 to "closed" so that the heat from the coolant is not released into the atmosphere (S1609). When the second switching valve 82 is "closed", the system switches to the bypass passage 8b-2, which does not allow the coolant to flow to the radiator 3. If the coolant temperature is 20 degrees Celsius or higher (NO in S1608), the switching valve opening / closing determination unit 109 sets the second switching valve 82 to "open" (S1610). When the second switching valve 82 is "open", the system switches to the coolant passage that allows the coolant to flow to the radiator 3, and heat is released from the coolant to the air outside the vehicle.

[0091] After the processing in step S1609 or S1610 in Figure 7, the process returns to the flowchart shown in Figure 4, and the processing (S0 to S16) in the flowchart of Figure 4 is repeated.

[0092] Next, the process of acquiring the learned oil temperature (S9) according to one embodiment of the present invention will be described with reference to Figure 8. Figure 8 is a flowchart showing an example of the procedure for acquiring the learned oil temperature according to one embodiment of the present invention. The control device 92 executes the process of acquiring the learned oil temperature according to the flowchart shown in Figure 8.

[0093] In acquiring the learned oil temperature, the warm-up on / off control determination unit 101 first reads the learned oil temperature from the learning result storage unit 924 (S901). If it is the first run or the learning result has been reset, the ROM 922 is accessed and a predetermined initial value for the learned oil temperature is read. Here, the initial value for the learned oil temperature is set to -10 degrees Celsius.

[0094] Next, the warm-up on / off control determination unit 101 determines whether the oil flow rate detected in step S6 (Figure 4) is less than or equal to a predetermined learn-permit flow rate (S902). If the oil flow rate is less than the predetermined learn-permit flow rate (YES in S902), the oil temperature learning is not permitted, and this process is terminated.

[0095] If the oil flow rate is greater than or equal to a predetermined learning permission flow rate (NO in S902), the warm-up on / off control determination unit 101 determines whether the time change (amount of change) of the oil pump target rotation speed exceeds a predetermined learning permission amount (S903). If the amount of change of the oil pump target rotation speed exceeds a predetermined learning permission amount (YES in S903), the oil temperature learning is not permitted, and this process is terminated.

[0096] If the time change (amount of change) of the target rotational speed of the oil pump is less than or equal to a predetermined learning permission amount (NO in S903), the warm-up on / off control determination unit 101 determines whether the oil temperature is higher than a predetermined learning upper limit oil temperature (S904). If the oil temperature is higher than the predetermined learning upper limit oil temperature (YES in S904), the process proceeds to step S910. In this case, learning of the oil temperature after warm-up is not permitted.

[0097] If the oil temperature is below a predetermined learning upper limit oil temperature (NO in S904), the warm-up on / off control determination unit 101 determines whether or not the oil temperature is rising (S905). If the oil temperature is not rising (NO in S905), the process proceeds to step S910.

[0098] If the oil temperature is rising (YES in S905), the warm-up on / off control determination unit 101 determines whether the differential value of oil pump power consumption or the change in oil pump power consumption calculated in step S8 (Figure 4) above is decreasing over time (S906). If the differential value of oil pump power consumption is increasing (NO in S906), the process proceeds to step S910. This indicates that the kinematic viscosity of the oil is increasing.

[0099] If the differential value of the oil pump power consumption or the change in the amount of oil pump power consumption is decreasing over time (YES in S906), the warm-up on / off control determination unit 101 determines whether the differential value of the oil pump power consumption or the change in the amount of oil pump power consumption is greater than a predetermined value, for example, whether the differential value of the pump power consumption is greater than 0.1 [W / s] (S907). If the differential value of the oil pump power consumption or the change in the amount of oil pump power consumption is greater than the predetermined value (YES in S907), this process is terminated.

[0100] If the differential value of the oil pump power consumption or the change in oil pump power consumption is less than or equal to a predetermined value (NO in S907), the warm-up on / off control determination unit 101 determines whether the learning flag F_TOILADPT (Figure 4) is 1 or not (S908). If the learning flag F_TOILADPT is 1 (YES in S908), the oil temperature has been adjusted and this process is terminated.

[0101] If the learning flag F_TOILADPT is zero (NO in S908), the warm-up on / off control determination unit 101 overwrites and updates the learned oil temperature with the current oil temperature detected in step S0 (Figure 4) described above (S909). At this time, the warm-up on / off control determination unit 101 stores the updated learned oil temperature in the learning result storage unit 924, and further sets the learning flag F_TOILADPT to 1 to terminate the learned oil temperature acquisition (S9) process.

[0102] If the answer to step S904 is YES, step S905 is NO, or step S906 is NO, the warm-up on / off control determination unit 101 sets the learning flag F_TOILADPT to 1 (S910). Then, the warm-up on / off control determination unit 101 terminates the learning oil temperature acquisition (S9) process without updating the learning oil temperature.

[0103] After the completion of the learning oil temperature acquisition (S9) shown in Figure 8, the process returns to the flowchart shown in Figure 4, and the processing from step S10 onwards is carried out.

[0104] [Warm-up control mode during shutdown] Next, the operation of the warm-up control during shutdown in one embodiment of the present invention will be explained using Figures 9 to 11.

[0105] Figure 9 shows an example of the kinematic viscosity characteristics with respect to oil temperature. In Figure 9, at an oil temperature of -20 degrees Celsius, the kinematic viscosity is 1080 mmHg. ２ Although it is large at [ / s], the kinematic viscosity is 220 [mm²] at an oil temperature of 0 degC. ２The characteristic is that it decreases to [W / s]. As a result, the oil pump power consumption [W] decreases as the oil temperature rises. Also, as shown in Figure 9, the change in kinematic viscosity with respect to oil temperature change in the range of -20 degC to 0 degC (the slope of the graph in Figure 9) is greater than the change in kinematic viscosity with respect to oil temperature change in the range of 0 degC to 40 degC. As a result, the differential value of oil pump power consumption [W / s] in the range of -20 degC to 0 degC is greater than the differential value of oil pump power consumption [W / s] in the range of 0 degC to 40 degC.

[0106] Figure 10 shows the difference in gear loss of the electric vehicle 1 when the warm-up control of the present invention is implemented and when the warm-up control is not implemented. Gear loss is friction loss that occurs in the gears of the gearbox 23, etc. Figure 10 shows a timing chart with time [s] on the common horizontal axis, showing the "key signal" which is a signal indicating the determination result of the power switch determination (Figure 4, S0) described above, vehicle speed [km / h], warm-up power input [kW], oil pump power consumption per 1 L / min [W], oil pump power consumption derivative [W / s], oil temperature [degC], and gear loss [kW]. Note that in the timing chart, the oil pump power consumption derivative is written as "oil pump power derivative". Also, if a negative derivative is obtained when calculating the oil pump power consumption derivative, the negative sign is inverted and displayed on the graph.

[0107] In the example shown in Figure 10, the World Wide-Harmonized Light Vehicle Test Cycle (WLTC) is applied to the driving conditions, with the WLTC start time set to 0 seconds. Furthermore, the oil used in the electric vehicle 1 has the kinematic viscosity characteristics shown in Figure 9.

[0108] (When stop-time warm-up control is not performed) First, let's explain the operation when stop-time warm-up control, which is the comparison target, is not performed. In Figure 10, the operation when stop-time warm-up control is not performed is shown by a dashed line. In the dashed line in Figure 10, the coolant temperature and oil temperature at the left end are the same as the ambient temperature, -20 degrees Celsius. Here, the learned oil temperature and the learned upper limit oil temperature (see Figure 8, S904) are experimentally set to -25 degrees Celsius. In addition, the learned permitted flow rate (see Figure 8, S902) is experimentally set to a value that exceeds the maximum flow rate of the electric oil pump 24. In other words, experimentally, the above-mentioned stop-time warm-up control (S13), driving warm-up control (S14), and learned oil temperature acquisition (S9) are pre-set so that they are not performed.

[0109] In the dashed line of Figure 10, the coolant flow rate and oil flow rate are zero during the period from the left end to the WLTC start timing because the "key signal" is off.

[0110] Immediately after the key signal switches from off to on at the start of WLTC, the oil temperature is low at -20°C and the kinematic viscosity is 1080 mm². ２ The value is large at [ / s]. Moreover, since the oil temperature is greater than the value of -25 degC set as the learned oil temperature, the above-mentioned warm-up control during stopping and warm-up control during driving are not performed. For this reason, when the motor 22 is energized from the inverter 21 to move the electric vehicle 1 along the WLTC after the key signal switches from off to on, the vehicle speed [km / h] turns positive and the power consumption of the electric oil pump 24 per 1 [L / min] of oil flow reaches a maximum of 180W. When the electric vehicle 1 starts moving from here, the vehicle speed [km / h] turns positive and heat is generated in the coil of the motor 22 due to losses. The oil is heated by this generated heat.

[0111] At this time, the first switching valve 81 is in the "closed" state, so the coolant flows through the bypass passage 8b-1 (Figure 1). Therefore, heat from the oil is not transferred to the coolant, and the oil temperature gradually rises as the WLTC progresses. As a result, the kinematic viscosity of the oil decreases as the WLTC progresses, and the power consumption of the electric oil pump 24 also decreases. If warm-up control is not performed, the oil temperature reaches 0 degrees Celsius around 1700 seconds towards the end of the WLTC.

[0112] (When warm-up control is performed while stopped) Next, the operation when warm-up control is performed while stopped will be explained. In Figure 10, the operation status when warm-up control is performed while stopped is shown by a solid line. In the solid line of Figure 10, the coolant temperature and oil temperature from the left end until the timing when the key signal switches from off to on is the same as the ambient temperature, -20 degC (low temperature). Here, the learned oil temperature is initially set to -10 degC. The learned upper limit oil temperature (Figure 8, S904) is set to 60 degC. In addition, the learned permitted flow rate (Figure 8, S902) is set to a value lower than the oil flow rate of the electric oil pump 24 set in warm-up control while stopped (S13). In other words, it is pre-set so that the warm-up control while stopped (S13), warm-up control while driving (S14), and acquisition of learned oil temperature (S9) described above can be executed from the timing when the key signal switches from off to on.

[0113] Furthermore, in the solid line of Figure 10, the coolant flow rate and oil flow rate are zero during the period from the left end until the key signal switches from off to on, because the "key signal" is off. Note that the driving pattern is WLTC, but the electric vehicle 1 starts moving after the warm-up control during stopping is completed.

[0114] In the solid line of Figure 10, when the key signal switches from off to on, the arithmetic unit 921 reads the learned oil temperature, which is set to -10 degrees Celsius, from the learning result storage unit 924. Furthermore, the oil temperature, ambient temperature, motor speed, and target motor speed are read into the arithmetic unit 921. Here, the oil temperature is the same as the ambient temperature, -20 degrees Celsius. Therefore, at the timing when the key signal switches from off to on, the oil temperature is lower than the learned oil temperature (-10 degrees Celsius), and both the motor speed and target motor speed are 0 [r / min], meaning the electric vehicle 1 is in a stopped state. For this reason, when the key signal switches from off to on, the stop warm-up control (S13) is executed.

[0115] In the stop-time warm-up control (S13), the electric oil pump 24 is operated at a predetermined set value (target rotational speed) to start the circulation of oil to the oil cooler 25, motor 22, and gearbox 23.

[0116] Then, power is supplied to the motor 22 at the d-axis current value (inverter operation setting value) of the motor's vector control set for warm-up. Since the first switching valve 81 is in the "closed" state during stop-time warm-up control, the coolant flows through the bypass passage 8b-1 (Figure 1). Therefore, heat from the oil is not transferred to the coolant, and the oil temperature rises as the stop-time warm-up control begins. In the solid line of Figure 10, at the WLTC start timing when the stop-time warm-up control ends, the oil temperature has reached -1.5 degrees Celsius.

[0117] As the oil temperature rises during the warm-up control while stopped, the kinematic viscosity of the oil decreases. As a result, the power consumption of the oil pump, which recorded a peak value of 130W per 1 L / min of oil flow rate immediately after the electric oil pump 24 started operating, decreases to 20W 90 seconds after the warm-up control started (when driving began).

[0118] Therefore, in the gear loss graph of Figure 10, the gear loss shown by the solid line, "when warm-up control is performed," is lower than the gear loss shown by the dashed line, "when warm-up control is not performed."

[0119] In this embodiment, the threshold value for the derivative of the oil pump power consumption during the acquisition of the learned oil temperature (S9) is set to 0.1 [W / s] (Figure 8, S907). Therefore, the stop-time warm-up control is terminated 90 seconds after the start of the stop-time warm-up control (time 0s) when the derivative of the oil pump power consumption becomes 0.1 [W / s] or less. The oil temperature at the time the stop-time warm-up control is terminated is -1.5 degC, and this result is stored in the learning result storage unit 924 as the learned oil temperature (Figure 8, S909). In this way, the learned oil temperature is updated from the initial value of -10 degC to -1.5 degC.

[0120] Figure 11 shows the difference in power consumption during WLTC driving between cases where stop-time warm-up control is implemented and cases where stop-time warm-up control is not implemented. In Figure 11, the amount of power consumed when driving on the WLTC (electricity consumption [kWh]) is shown separately for the amount of power consumed by the driving resistance corresponding to the vehicle speed of the electric vehicle 1 during WLTC driving, the amount of power lost due to gear loss during the same WLTC driving, and the amount of warm-up power consumed before starting WLTC driving with stop-time warm-up control.

[0121] As shown in Figure 11, the energy consumption [kWh] is reduced by approximately 2.9% when WLTC driving with "stop-time warm-up control enabled" compared to when "stop-time warm-up control disabled". Specifically, the sum of the amount of energy lost due to gear loss and the amount of energy used for warming up during WLTC driving with stop-time warm-up control enabled is approximately 2.9% less than the amount of energy lost due to gear loss during WLTC driving without stop-time warm-up control enabled. In other words, when stop-time warm-up control is enabled, even after subtracting the amount of energy used for warming up during stop-time warm-up control, it is possible to comprehensively improve the energy consumption [kWh] of the electric vehicle 1 compared to when stop-time warm-up control is disabled.

[0122] [Acquiring Learned Oil Temperature] Next, the operation of acquiring the learned oil temperature according to one embodiment of the present invention will be explained with reference to Figures 12 to 14. An example of a scenario assumed is one in which the kinematic viscosity characteristics of the oil with respect to temperature have changed because the user has changed the oil.

[0123] Figure 12 shows examples of the kinematic viscosity characteristics with respect to oil temperature for the "low viscosity oil" shown in Figure 9 and the "high viscosity oil" which has a higher kinematic viscosity than the low viscosity oil in Figure 9. As shown in Figure 12, the kinematic viscosity of the low viscosity oil at an oil temperature of 0 degrees Celsius is 220 mm². ２ [ / s]. In contrast, for high-viscosity oil, the kinematic viscosity at an oil temperature of 0 degrees Celsius is 900 [mm²]. ２ The kinematic viscosity is higher than that of low-viscosity oils, as shown by [ / s]. Furthermore, in high-viscosity oils, the kinematic viscosity decreases as the oil temperature rises, dropping to the same level as low-viscosity oils at 70 degC.

[0124] Although the kinematic viscosity characteristics of low-viscosity and high-viscosity oils differ significantly, their specific heat remains almost the same. Therefore, for example, the time required to raise the oil temperature from -20°C to -1.5°C is almost the same for both low-viscosity and high-viscosity oils.

[0125] Next, with reference to Figure 13, we will explain the results when learning oil temperature acquisition according to this embodiment is performed and when learning oil temperature acquisition is not performed in a scenario where the kinematic viscosity characteristics with respect to oil temperature have changed due to the user changing the oil.

[0126] Figure 13 shows the difference in gear loss for electric vehicle 1 when learning oil temperature acquisition is performed and when learning oil temperature acquisition is not performed. In Figure 13, the common horizontal axis is time [s], and timing charts are shown for the "key signal," which is a signal indicating the judgment result of the power switch judgment (Figure 4, S0) described above, as well as vehicle speed [km / h], warm-up power input [kW], oil pump power consumption per 1 L / min [W], oil pump power consumption derivative [W / s], oil temperature [degC], and gear loss [kW]. Note that in the timing chart, the oil pump power consumption derivative is written as "oil pump power derivative". Also, if a negative derivative is obtained when calculating the oil pump power consumption derivative, the negative sign is inverted and displayed on the graph.

[0127] (When learning oil temperature acquisition is not performed) First, we will explain the operation when stop-time warm-up control is performed without learning oil temperature acquisition, which is the comparison point. In Figure 13, the operation status when stop-time warm-up control is performed without learning oil temperature acquisition is shown by a dashed line.

[0128] In the dashed line of Figure 13, the coolant temperature and oil temperature at the leftmost end are -20 degrees Celsius, the same as the ambient temperature. Here, the learning oil temperature is experimentally set to -1.5 degrees Celsius, which corresponds to the learning oil temperature of low viscosity oil. Also, the learning upper limit oil temperature (see Figure 8, S904) is experimentally set to -30 degrees Celsius. In other words, experimentally, the above-mentioned warm-up control during stopping (S13) and warm-up control during driving (S14) are executed, but the acquisition of the learning oil temperature (S9) is pre-set not to be executed.

[0129] Furthermore, in the dashed line of Figure 13, the coolant flow rate and oil flow rate are zero during the period from the left end until the key signal switches from off to on, because the "key signal" is off. Note that the driving pattern is WLTC, but the electric vehicle 1 starts driving after the warm-up control during stopping has finished.

[0130] In the dashed line of Figure 13, when the key signal switches from off to on, the arithmetic unit 921 reads the learned oil temperature, which is set to -1.5 degrees C, from the learning result storage unit 924. Furthermore, the oil temperature, ambient temperature, motor speed, and target motor speed are read into the arithmetic unit 921. Here, the oil temperature is the same as the ambient temperature, -20 degrees C. Therefore, at the timing when the key signal switches from off to on, the oil temperature is lower than the learned oil temperature (-1.5 degrees C), and both the motor speed and target motor speed are 0 [r / min], meaning the electric vehicle 1 is stopped. For this reason, when the key signal switches from off to on, the stop warm-up control (S13) is executed.

[0131] During the stop-time warm-up control (S13), the electric oil pump 24 is activated (Figure 5, S1306) to start circulating oil to the oil cooler 25, motor 22, and gearbox 23.

[0132] Then, power is supplied to the motor 22 at the inverter operation setting value set for warm-up (Figure 5, S1304). Since the first switching valve 81 is in the "closed" state during stop-time warm-up control, the coolant flows through the bypass passage 8b-1 (Figure 1). Therefore, heat from the oil is not transferred to the coolant, and the oil temperature rises as soon as the stop-time warm-up control starts. In the dashed line of Figure 13, the stop-time warm-up control ends and WLTC driving begins when the oil temperature reaches the learned oil temperature of -1.5 degC.

[0133] As the oil temperature rises during warm-up control while stopped, the kinematic viscosity of the high-viscosity oil decreases. As a result, the oil pump power consumption, which recorded a peak value of over 500W per 1 L / min of oil flow rate immediately after the electric oil pump 24 started operating, decreased to about 100W by the time WLTC driving began. However, this oil pump power consumption is five times higher than the oil pump power consumption (20W) at the start of WLTC driving when using low-viscosity oil, as shown by the solid line in Figure 12 above. In other words, if the user does not perform "learned oil temperature acquisition" when changing from low-viscosity oil to high-viscosity oil, the electric vehicle 1 will start driving at the learned oil temperature of -1.5 degC for low-viscosity oil, resulting in very large gear losses.

[0134] (When learning oil temperature acquisition is performed) Next, we will explain the operation when warm-up control is performed while learning oil temperature acquisition is performed. In Figure 13, the operation status when warm-up control is performed while learning oil temperature acquisition is performed is shown by a solid line.

[0135] In the solid line of Figure 13, the coolant temperature and oil temperature at the leftmost end are -20 degrees Celsius, the same as the ambient temperature. Here, the learning oil temperature is set to -1.5 degrees Celsius, which corresponds to the learning oil temperature of low-viscosity oil. In addition, the learning upper limit oil temperature (see Figure 8, S904) is set to 60 degrees Celsius. In other words, the above-mentioned warm-up control during stopping (S13), warm-up control during driving (S14), and acquisition of the learning oil temperature (S9) are pre-configured to be executable.

[0136] Furthermore, in the solid line of Figure 13, the coolant flow rate and oil flow rate are zero during the period from the left end until the key signal switches from off to on, because the "key signal" is off. Note that the driving pattern is WLTC, but the electric vehicle 1 starts moving after the warm-up control during stopping is completed.

[0137] In the solid line of Figure 13, when the key signal switches from off to on, the arithmetic unit 921 reads the learned oil temperature, which is set to -1.5 degrees C, from the learning result storage unit 924. Furthermore, the oil temperature, ambient temperature, motor speed, and target motor speed are read into the arithmetic unit 921. Here, the oil temperature is the same as the ambient temperature, -20 degrees C. Therefore, at the timing when the key signal switches from off to on, the oil temperature is lower than the learned oil temperature (-1.5 degrees C), and both the motor speed and target motor speed are 0 [r / min], meaning the electric vehicle 1 is stopped. For this reason, when the key signal switches from off to on, the stop warm-up control (S13) is executed.

[0138] In the stop-time warm-up control (S13), the electric oil pump 24 is operated at a predetermined set value (target rotation speed) (Figure 5, S1306) to start the circulation of oil to the oil cooler 25, motor 22, and gearbox 23.

[0139] Then, power is supplied to the motor 22 at the inverter operation setting value set for warm-up (Figure 5, S1304). At this point, the first switching valve 81 is in the "closed" state during stop-time warm-up control, so the coolant flows through the bypass passage 8b-1 (Figure 1). Consequently, the heat from the oil is not transferred to the coolant, and the oil temperature rises as soon as the stop-time warm-up control starts.

[0140] In this embodiment, the threshold value of the derivative of the oil pump power consumption during learning oil temperature acquisition (S9) is set to 0.1 [W / s] (Figure 8, S907). However, as shown by the solid line in Figure 13, the derivative of the oil pump power consumption at the timing when the high viscosity oil temperature reaches the learning oil temperature of -1.5 degC for low viscosity oil is a large 1.5 [W / s]. For this reason, even if the high viscosity oil temperature exceeds the learning oil temperature of -1.5 degC for low viscosity oil, the stop-time warm-up control continues.

[0141] In the solid line of Figure 13, when the oil temperature reaches the learned oil temperature of -1.5 degC, the stop-time warm-up control is terminated and WLTC driving begins. The calculation unit 921 monitors the differential value of the oil pump power consumption and continues the stop-time warm-up control even if the oil temperature exceeds the learned oil temperature of -1.5 degC. Finally, the calculation unit 921 stops the stop-time warm-up control when the differential value becomes 0.1 [W / s] or less (Figure 8, S907), 298 seconds after the start of the stop-time warm-up control. At that time, the high-viscosity oil temperature is 25 degC, and this result is stored in the learning result storage unit 924 as the learned oil temperature (Figure 8, S909). In this way, when learning oil temperature acquisition (S9) is performed, the learned oil temperature is updated from -1.5 degC, which is the learned oil temperature for low-viscosity oil, to 25 degC, which is the learned oil temperature for high-viscosity oil.

[0142] Figure 14 shows the difference in power consumption during WLTC driving between cases where learning oil temperature acquisition is performed and cases where learning oil temperature acquisition is not performed. In Figure 14, the amount of power consumed when driving on the WLTC (electricity consumption [kWh]) is shown separately for the amount of power converted to the vehicle speed of electric vehicle 1 during WLTC driving of electric vehicle 1, the amount of power lost due to gear loss during the same WLTC driving, and the amount of warm-up power consumed before starting WLTC driving by stop warm-up control.

[0143] As shown in Figure 14, in WLTC driving where learning oil temperature acquisition is not performed, i.e., with a "fixed threshold temperature," the energy consumption [kWh] is reduced by about 7.7% compared to when learning oil temperature acquisition is performed, i.e., with a "fixed and variable threshold temperature." More specifically, the sum of the amount of energy lost due to gear loss and the amount of energy consumed for warm-up control during WLTC driving with learning oil temperature acquisition is about 7.7% less than the sum of the amount of energy lost due to gear loss and the amount of energy consumed for warm-up control during WLTC driving without learning oil temperature acquisition.

[0144] Thus, when learning oil temperature acquisition is performed, even after accounting for the increase in the amount of power input required for warm-up control during stopping due to the user changing from low-viscosity oil to high-viscosity oil (in the scene in Figure 13, the warm-up time increases from 90 seconds to 298 seconds), it is possible to comprehensively improve the power consumption [kWh] of the electric vehicle 1.

[0145] [Driving Warm-Up Control Mode] Next, the operation of the driving warm-up control in one embodiment of the present invention will be described with reference to Figure 15.

[0146] Figure 15 shows examples of gear loss in an electric vehicle 1 when the warm-up control during driving according to the present invention is implemented and when the warm-up control during driving is not implemented. In Figure 15, a timing chart is shown with time [s] on the common horizontal axis, showing the key signal, vehicle speed [km / h], warm-up power input [kW], oil pump power consumption per 1 L / min [W], oil pump power consumption derivative [W / s], oil temperature [degC], and gear loss [kW]. Period WCS1 and the subsequent period WCS2 represent the warm-up control during stopping, and period WCD represents the warm-up control during driving.

[0147] In the example shown in Figure 15, the World Long-Term Test Cycle (WLTC) is applied to the driving conditions, with the WLTC start time set to 0 seconds. Furthermore, the oil used in the electric vehicle 1 is the low-viscosity oil shown in Figure 9 or Figure 12.

[0148] (When warm-up control is not performed after the start of driving) First, we will explain the operation when warm-up control is not performed after the start of driving, which is the point of comparison. In Figure 15, the operation when warm-up control is not performed while driving is shown by a dashed line.

[0149] In the dashed line of Figure 15, the coolant temperature and oil temperature from the left end until the key signal switches from off to on are the same as the ambient temperature, -20 degrees Celsius. Here, the learned oil temperature is set to -1.5 degrees Celsius. The learned upper limit oil temperature (see Figure 8, S904) is set to 60 degrees Celsius. In addition, the learned permitted flow rate (Figure 8, S902) is experimentally set to a value that exceeds the maximum flow rate of the electric oil pump 24. Furthermore, the setting value for the number of times the warm-up control is executed #CTWUP (S1301, S1401) is experimentally set to 1 [time]. That is, experimentally, the above-mentioned stop-time warm-up control (S13) is executed only once after the key signal switches from off to on, but the driving-time warm-up control (S14) and learned oil temperature acquisition (S9) are pre-set not to be executed.

[0150] In the dashed line of Figure 15, the coolant flow rate and oil flow rate are zero from the left end to the WLTC start timing because the "key signal" is off. Although the driving pattern is WLTC, the electric vehicle 1 starts moving before the oil temperature rise due to the stop warm-up control is complete.

[0151] In the dashed line of Figure 15, when the key signal switches from off to on, the arithmetic unit 921 reads the learned oil temperature, which is set to -1.5 degrees C, from the learning result storage unit 924. Furthermore, the oil temperature, ambient temperature, motor speed, and target motor speed are read into the arithmetic unit 921. Here, the oil temperature is the same as the ambient temperature, -20 degrees C. Therefore, at the timing when the key signal switches from off to on, the oil temperature is lower than the learned oil temperature (-1.5 degrees C), and both the motor speed and target motor speed are 0 [r / min], meaning the electric vehicle 1 is stopped. For this reason, when the key signal switches from off to on, the stop warm-up control (S13) is executed. At this time, although not shown in Figure 15, the warm-up control execution count CTWUP is incremented and set to "#1".

[0152] In the stop-time warm-up control (S13), the electric oil pump 24 is operated at a predetermined set value (target rotation speed) (Figure 5, S1306) to start the circulation of oil to the oil cooler 25, motor 22, and gearbox 23.

[0153] Then, power is supplied to the motor 22 at the inverter operation setting value set for warm-up (Figure 5, S1304). Since the first switching valve 81 is in the "closed" state during stop-time warm-up control, the coolant flows through the bypass passage 8b-1 (Figure 1). Therefore, the heat from the oil is not transferred to the coolant, and the oil temperature rises as soon as the stop-time warm-up control starts.

[0154] In the dashed line of Figure 15, the driver decides to start driving the electric vehicle 1 when the oil temperature reaches -12 degrees C, 30 seconds after the start of the stop-time warm-up control, before it reaches the learned oil temperature -1.5 degrees C. At this point, if the motor target rotational speed becomes greater than 0 [r / min] due to the driver's accelerator operation, the stop-time warm-up control is interrupted and the system switches to the driving warm-up control mode (S14) (Figure 4, S11, S12). In other words, the stop-time warm-up control is stopped before driving begins due to the driver's accelerator operation.

[0155] In the running warm-up control mode (S14), as described above, the set value for the number of warm-up control executions #CTWUP (S1301, S1401) is experimentally set to 1 [times], and the warm-up control execution count CTWUP is incremented to "#1". Therefore, the motor energization is performed in essentially the same way as in the normal control mode (S15). That is, similar to the normal control mode (S15), the d-axis current value and q-axis current value of the motor's vector control are set so that the efficiency of the motor 22 is appropriate, and current is supplied from the inverter 21 to the UVW phase (see Figure 1) of the motor 22. As a result, the switching control of the inverter 21 is performed so that a rotating magnetic field is formed in the coil, the motor 22 rotates at the target rotational speed, and the desired rotational torque is generated.

[0156] In the dashed line of Figure 15, the electric vehicle 1 comes to a stop 91 seconds after the start of driving (after the WCD period has elapsed). At this timing, the oil temperature is -16 degrees Celsius, which is below the learning oil temperature of low viscosity oil, which is -1.5 degrees Celsius. However, the warm-up control execution count CTWUP has been incremented to "#1". Therefore, the warm-up control during stopping is not restarted even if the electric vehicle 1 comes to a stop.

[0157] Even after the WCD period has elapsed, the first switching valve 81 remains in the "closed" state, so the coolant flows through the bypass passage 8b-1 (Figure 1). Therefore, even after the WCD period has elapsed, the heat from the oil is not transferred to the coolant, and the oil temperature gradually rises as WLTC progresses. As a result, the kinematic viscosity of the oil decreases as WLTC progresses, and the power consumption of the electric oil pump 24 decreases accordingly. If warm-up control is not performed, the oil temperature reaches the learned oil temperature - 1.5 degrees C at around 1650 seconds towards the end of WLTC.

[0158] (When warm-up control is performed after the start of driving) Next, we will explain the operation when warm-up control is performed before and after the start of driving. In Figure 15, the operation status when warm-up control is performed while stopped and warm-up control is performed while driving is performed is shown by solid lines.

[0159] In the solid line of Figure 15, the coolant temperature and oil temperature from the left end to the timing when the key signal switches from off to on are the same as the ambient temperature, -20 degrees Celsius. Here, the learned oil temperature is set to -1.5 degrees Celsius. The learned upper limit oil temperature (see Figure 8, S904) is set to 60 degrees Celsius. In addition, the learned permitted flow rate (see Figure 8) is set to a value lower than the oil flow rate of the electric oil pump 24 set in the stop warm-up control (S13). Furthermore, the set value for the number of warm-up control executions #CTWUP (S1301, S1401) is experimentally set to 3 [times]. In other words, it is pre-set to perform a total of three warm-up control operations: a warm-up control operation while stopped before starting WLTC driving (S13), a warm-up control operation while driving after starting WLTC driving (S14), and a second warm-up control operation while stopped (S13) which is performed when the electric vehicle 1 comes to a complete stop after starting WLTC driving, as well as learning oil temperature acquisition (S9).

[0160] In the solid line of Figure 15, the coolant flow rate and oil flow rate are zero from the left end to the WLTC start timing because the "key signal" is off. Although the driving pattern is WLTC, the electric vehicle 1 starts moving before the oil temperature rise due to the stop warm-up control is complete.

[0161] In the solid line of Figure 15, when the key signal switches from off to on, the arithmetic unit 921 reads the learned oil temperature, which is set to -1.5 degrees C, from the learning result storage unit 924. Furthermore, the oil temperature, ambient temperature, motor speed, and target motor speed are read into the arithmetic unit 921. Here, the oil temperature is the same as the ambient temperature, -20 degrees C. Therefore, at the timing when the key signal switches from off to on, the oil temperature is lower than the learned oil temperature (-1.5 degrees C), and both the motor speed and target motor speed are 0 [r / min], meaning the electric vehicle 1 is in a stopped state. For this reason, when the key signal switches from off to on, the stop warm-up control (S13) is executed. At this time, although not shown in Figure 15, the warm-up control execution count CTWUP is incremented and set to "#1" (Figure 5, S1303).

[0162] In the stop-time warm-up control (S13), the electric oil pump 24 is operated at a predetermined set value (target rotation speed) (Figure 5, S1306) to start the circulation of oil to the oil cooler 25, motor 22, and gearbox 23.

[0163] Then, power is supplied to the motor 22 at the inverter operation setting value set for warm-up (Figure 5, S1304). Since the first switching valve 81 is in the "closed" state during stop-time warm-up control, the coolant flows through the bypass passage 8b-1 (Figure 1). Therefore, the heat from the oil is not transferred to the coolant, and the oil temperature rises as soon as the stop-time warm-up control starts.

[0164] In the solid line of Figure 15, the electric vehicle 1 starts running at a timing of -12 degrees C, 30 seconds after the start of the stop-time warm-up control, before the oil temperature reaches the learned oil temperature -1.5 degrees C. When the motor target rotational speed becomes greater than 0 [r / min] due to the driver's accelerator operation at the -12 degrees C timing, the stop-time warm-up control is stopped and the mode switches to running warm-up control mode (S14) (see Figure 4, S12). At this time, the warm-up control execution count CTWUP is incremented again and set to "#2" (Figure 6, S1403).

[0165] In the warm-up control mode during driving (S14), as described above, an inverter operation setting value is set to increase the d-axis current value of the motor 22's vector control in order to raise the oil temperature.

[0166] In the solid line of Figure 15, the electric vehicle 1 comes to a stop 91 seconds after the start of driving (after the WCD period has elapsed). However, since the oil temperature is -5 degrees C and the differential value of the oil pump power consumption is greater than the threshold (Figure 8, S907), the warm-up control continues. Here, because the motor speed and motor target speed are 0 [r / min] due to the stop, the warm-up control during driving (S14) is stopped and the system switches to the second warm-up control mode during stopping (S13) (Figure 4, S11, S12). At this time, the warm-up control execution count CTWUP is incremented again and set to "#3" (Figure 5, S1303).

[0167] In the solid line of Figure 15, when the second stop-time warm-up control mode (S13) is executed after the WCD period has elapsed, the oil temperature is further increased. When the oil temperature rises and the differential value of the oil pump power consumption falls below the threshold of 0.1 [W / s], the second stop-time warm-up control is stopped (after the WCS2 period has elapsed). Thus, at the time when the second stop-time warm-up control is completed, the oil temperature is -1.5 degC, and the oil pump power consumption has decreased to 20W. In other words, in the scene of Figure 15, if warm-up control is performed after the start of driving, the oil temperature can be sufficiently raised before the WCS2 period has elapsed.

[0168] As described above, by performing warm-up control even while the electric vehicle 1 is running, the oil temperature can be sufficiently raised. Therefore, the increase in gear loss when the oil temperature is below the threshold temperature can be suppressed.

[0169] From another perspective, by configuring the system to perform warm-up control even while the electric vehicle 1 is in motion, the execution time of the stop-time warm-up control mode before the electric vehicle 1 starts moving can be shortened. For example, even if the driver presses the accelerator to start immediately after getting into the electric vehicle 1, the stop-time warm-up control is stopped, and the system switches to the running warm-up control mode (S14) to perform warm-up control. This makes it possible to raise the oil temperature quickly and sufficiently. This makes it possible to improve the convenience of the electric vehicle 1.

[0170] As described above, the electric vehicle control device (integrated ECU 9 (control device 92)) according to this embodiment is an electric vehicle control device that includes an electric drive device and an electric oil pump that circulates oil to the electric drive device, and performs warm-up control to raise the temperature of the oil by generating heat in the electric drive device (equipment in the electric drive unit 2). The electric vehicle control device includes an oil temperature detection unit (for example, a warm-up on / off control determination unit 101) that detects or estimates and acquires the oil temperature, a power consumption calculation unit (for example, an oil pump power consumption calculation unit 111) that determines the current value flowing through the motor of the electric oil pump and the oil flow rate per unit time by the electric oil pump, and calculates the power consumption of the electric oil pump per unit flow rate based on the current value and the oil flow rate, and an oil temperature adjustment unit (for example, a warm-up on / off control determination unit 101, a warm-up control mode determination unit 102, and a switching valve opening / closing determination unit 109) that adjusts the state of warm-up control based on the oil temperature and power consumption per unit flow rate. Adjusting the warm-up control state may include at least one of the following: starting / stopping the warm-up control, setting conditions for determining the start / stop of the warm-up control (e.g., learning oil temperature), and controlling equipment within the electric drive unit associated with the warm-up control (electric oil pump 24, inverter 21 (motor 22), first switching valve 81, second switching valve 82, etc.).

[0171] In this embodiment of the electric vehicle control device, the warm-up control is stopped when the actual kinematic viscosity of the oil becomes sufficiently low. As a result, this embodiment can appropriately raise the oil temperature even when the kinematic viscosity characteristics (viscosity) of the oil (lubricant) change due to contamination, deterioration, replacement, etc. of the oil (lubricant). Therefore, the rotational resistance of the electric vehicle can be reduced and the driving range can be extended.

[0172] Furthermore, in the electric vehicle control device according to this embodiment, the power consumption calculation unit acquires time-series data of the power consumption per unit flow rate of the electric oil pump during the operating period of the electric oil pump, calculates the amount of change per unit time of the power consumption per unit flow rate of the electric oil pump based on the time-series data, and stops the warm-up control when the amount of change per unit time of the power consumption per unit flow rate falls below a threshold.

[0173] The electric vehicle control device of this embodiment can accurately grasp the actual state of the oil used in the electric vehicle based on the change in power consumption per unit time per unit flow rate, and can appropriately raise the oil temperature. Therefore, the electric vehicle control device can reduce the rotational resistance of the electric vehicle and extend its driving range.

[0174] Furthermore, in the electric vehicle control device according to this embodiment, the power consumption calculation unit acquires time-series data of power consumption per unit flow rate of the electric oil pump during the operating period of the electric oil pump, calculates the amount of change per unit time of power consumption per unit flow rate of the electric oil pump based on the time-series data, and the oil temperature control unit learns the oil temperature at the time when it is determined that the amount of change per unit time of power consumption per unit flow rate matches a threshold as the learned oil temperature, starts warm-up control when the oil temperature acquired by the oil temperature detection unit after learning the learned oil temperature falls below the learned oil temperature, and stops warm-up control when the oil temperature acquired by the oil temperature detection unit after learning the learned oil temperature falls above the learned oil temperature.

[0175] In this embodiment, the electric vehicle control device accurately determines the oil temperature at which the kinematic viscosity actually saturates (learned oil temperature) based on the change in power consumption per unit time per unit flow rate of the electric oil pump. The electric vehicle control device can then perform warm-up control to appropriately raise the oil temperature when the oil temperature falls below the learned oil temperature. Therefore, the electric vehicle control device can reduce the rotational resistance of the electric vehicle and extend its driving range.

[0176] Furthermore, in the electric vehicle control device according to this embodiment, the power consumption calculation unit acquires time-series data of the power consumption per unit flow rate of the electric oil pump during the operating period of the electric oil pump, calculates the differential value of the oil pump power consumption obtained by differentiating the power consumption per unit flow rate of the electric oil pump once with respect to time based on the time-series data, and the oil temperature control unit stops the warm-up control when the differential value of the oil pump power consumption falls below a threshold.

[0177] The electric vehicle control device of this embodiment can accurately determine the actual state of the oil used in the electric vehicle based on the differential value of the oil pump's power consumption, and can appropriately raise the oil temperature. Therefore, the electric vehicle control device can reduce the rotational resistance of the electric vehicle and extend its driving range.

[0178] Furthermore, in the electric vehicle control device according to this embodiment, the power consumption calculation unit acquires time-series data of the power consumption per unit flow rate of the electric oil pump during the operating period of the electric oil pump, calculates the differential value of the oil pump power consumption obtained by differentiating the power consumption per unit flow rate of the electric oil pump once with respect to time based on the time-series data, the oil temperature control unit learns the oil temperature at the time when it is determined that the differential value of the oil pump power consumption matches a threshold as the learned oil temperature, the oil temperature control unit starts warm-up control when the oil temperature acquired by the oil temperature detection unit after learning the learned oil temperature falls below the learned oil temperature, and the oil temperature control unit stops warm-up control when the oil temperature acquired by the oil temperature detection unit after learning the learned oil temperature falls above the learned oil temperature.

[0179] In this embodiment, the electric vehicle control device accurately determines the oil temperature at which the kinematic viscosity actually saturates (learned oil temperature) based on the derivative of the oil pump power consumption, which is obtained by differentiating the power consumption per unit flow rate of the electric oil pump once with respect to time. The electric vehicle control device can then perform warm-up control when the oil temperature falls below the learned oil temperature to appropriately raise the oil temperature. Therefore, the electric vehicle control device can reduce the rotational resistance of the electric vehicle and extend its driving range.

[0180] Furthermore, the electric drive device according to this embodiment is, as an example, a mechatronic integrated electric drive unit having an electric motor (motor 22), gears for rotating the wheels, an oil cooler, and an inverter for driving the electric motor. Each component within the electric drive unit is controlled by the electric vehicle control device described above.

[0181] According to this embodiment, for example, the heat generated in the inverter 21 can be transferred to the oil circulating in the electric drive unit instead of to the cooling water. This makes it possible to save the warm-up power [kW] supplied to the motor 22 via the inverter 21 during warm-up control. Therefore, the energy efficiency of the electric vehicle can be improved and the driving range can be extended.

[0182] The electric vehicle control method according to this embodiment is an electric vehicle control method that performs warm-up control by generating heat in an electric drive unit and raising the temperature of the oil circulated to the electric drive unit by an electric oil pump, and comprises an oil temperature detection process that detects or estimates and obtains the oil temperature, a power consumption calculation process that determines the current value flowing through the motor of the electric oil pump and the oil flow rate per unit time by the electric oil pump and calculates the power consumption of the electric oil pump per unit flow rate based on the current value and the oil flow rate, and an oil temperature adjustment process that adjusts the state of warm-up control based on the oil temperature and the power consumption per unit flow rate.

[0183] According to this embodiment of the electric vehicle control method, the warm-up control is stopped when the actual kinematic viscosity of the oil becomes sufficiently low. As a result, this embodiment can appropriately raise the oil temperature even when the kinematic viscosity characteristics (viscosity) of the oil (lubricant) change due to contamination, deterioration, replacement, etc. of the oil (lubricant). Therefore, the rotational resistance of the electric vehicle can be reduced and the driving range can be extended.

[0184] The present invention is not limited to the embodiments described above, and various other modifications and applications are possible as long as they do not depart from the gist of the invention as described in the claims. For example, the embodiments described above are described in detail and specifically in order to explain the present invention in an easy-to-understand manner, and are not necessarily limited to those comprising all the components described. Furthermore, it is possible to add, replace, or delete other components in some of the components of each embodiment.

[0185] Furthermore, some or all of the above configurations, functions, and processing units may be implemented in hardware, for example, by designing them as integrated circuits. Broadly defined processor devices such as FPGAs (Field Programmable Gate Arrays) and ASICs (Application Specific Integrated Circuits) may be used as hardware.

[0186] Furthermore, in the embodiments described above, the control lines and information lines shown are those deemed necessary for explanatory purposes, and not all control lines and information lines are necessarily shown in the actual product. In practice, it can be assumed that almost all components are interconnected.

[0187] Furthermore, in this specification, processing steps describing chronological processing include not only processing performed chronologically in the order described, but also processing that is not necessarily performed chronologically but is executed in parallel or individually (for example, processing by objects). In addition, the processing order of processing steps describing chronological processing may be changed to the extent that it does not affect the processing result.

[0188] 1...Electric vehicle, 2...Electric drive unit, 3...Radiator, 4...High-voltage battery, 5...Charger, 6...DC / DC converter, 7...Cooling water pump, 8...Cooling water piping, 8b-1, 8b-2...Bypass passage, 9...Integrated ECU, 21...Inverter, 22...Motor, 23...Gearbox, 24...Electric oil pump, 25...Oil cooler, 26...Oil piping, 27...Oil temperature sensor, 28...Oil flow sensor, 31...Cooling water temperature sensor, 41...Battery temperature sensor, 71...Cooling water flow sensor, 81...First switching valve, 82...Second switching valve, 91...Input unit, 92...Control device, 93...Output unit, 101...Warm-up on / off control determination unit, 102...Warm-up control mode determination unit, 109...Switching valve opening / closing determination unit, 110...Inverter power consumption calculation unit, 111... Oil pump power consumption calculation unit, 921... arithmetic unit, 922... ROM, 923... RAM, 924... Learning result storage unit

Claims

1. An electric vehicle control device comprising an electric drive unit and an electric oil pump for circulating oil through the electric drive unit, and performing warm-up control to raise the temperature of the oil by generating heat in the electric drive unit, comprising: an oil temperature detection unit for detecting or estimating and acquiring the oil temperature; a power consumption calculation unit for determining the current value flowing through the motor of the electric oil pump and the oil flow rate per unit time by the electric oil pump, and calculating the power consumption of the electric oil pump per unit flow rate based on the current value and the oil flow rate; and an oil temperature adjustment unit for adjusting the state of the warm-up control based on the oil temperature and the power consumption per unit flow rate.

2. The electric vehicle control device according to claim 1, wherein the power consumption calculation unit acquires time-series data of the power consumption per unit flow rate of the electric oil pump during the operating period of the electric oil pump, calculates the amount of change per unit time of the power consumption per unit flow rate of the electric oil pump based on the time-series data, and the oil temperature control unit stops the warm-up control when the amount of change per unit time of the power consumption per unit flow rate falls below a threshold.

3. The electric vehicle control device according to claim 1, wherein the power consumption calculation unit acquires time-series data of the power consumption per unit flow rate of the electric oil pump during the operating period of the electric oil pump, calculates the amount of change per unit time of the power consumption per unit flow rate of the electric oil pump based on the time-series data, the oil temperature control unit learns the oil temperature at the time when it is determined that the amount of change per unit time of the power consumption per unit flow rate matches a threshold, the oil temperature control unit starts the warm-up control when the oil temperature acquired by the oil temperature detection unit after learning the learned oil temperature falls below the learned oil temperature, and the oil temperature control unit stops the warm-up control when the oil temperature acquired by the oil temperature detection unit after learning the learned oil temperature falls above the learned oil temperature.

4. The electric vehicle control device according to claim 1, wherein the power consumption calculation unit acquires time-series data of the power consumption per unit flow rate of the electric oil pump during the operating period of the electric oil pump, calculates an oil pump power consumption derivative value obtained by differentiating the power consumption per unit flow rate of the electric oil pump once with respect to time based on the time-series data, and the oil temperature control unit stops the warm-up control when the oil pump power consumption derivative value falls below a threshold.

5. The electric vehicle control device according to claim 1, wherein the power consumption calculation unit acquires time-series data of the power consumption per unit flow rate of the electric oil pump during the operating period of the electric oil pump, calculates an oil pump power consumption derivative value obtained by differentiating the power consumption per unit flow rate of the electric oil pump once with respect to time based on the time-series data, the oil temperature control unit learns the oil temperature at the time when it is determined that the oil pump power consumption derivative value matches a threshold as the learned oil temperature, the oil temperature control unit starts the warm-up control when the oil temperature acquired by the oil temperature detection unit after learning the learned oil temperature falls below the learned oil temperature, and the oil temperature control unit stops the warm-up control when the oil temperature acquired by the oil temperature detection unit after learning the learned oil temperature falls above the learned oil temperature.

6. An electric drive device controlled by an electric vehicle control device according to any one of claims 1 to 5, wherein the electric drive device is a mechatronic electric drive unit having an electric motor, gears for rotating wheels, an oil cooler, and an inverter for driving the electric motor.

7. An electric vehicle control method that performs warm-up control by generating heat in an electric drive unit and raising the temperature of the oil circulated to the electric drive unit by an electric oil pump, comprising: an oil temperature detection process that detects or estimates and obtains the oil temperature; a power consumption calculation process that determines the current value flowing through the motor of the electric oil pump and the oil flow rate per unit time by the electric oil pump, and calculates the power consumption of the electric oil pump per unit flow rate based on the current value and the oil flow rate; and an oil temperature adjustment process that adjusts the state of the warm-up control based on the oil temperature and the power consumption per unit flow rate.

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