Vehicle drive systems

Abstract

To warm up the oil in the power unit quickly. [Solution] The vehicle drive system has a power unit comprising an electric motor housed in a housing. The power unit includes an oil return passage for returning oil from a heat exchanger to the housing. The power unit comprises a first oil jacket covering the stator end face of the electric motor and a second oil jacket covering the outer circumferential surface of the stator of the electric motor. The power unit is provided with an on / off valve in a connecting passage that connects the oil return passage and the second oil jacket to each other, and which operates to open the connecting passage and close the connecting passage.

Description

Technical Field

[0004] , , , , , , , , , , , , , , ,

[0005] ,

[0001] The present disclosure relates to a drive device for a vehicle.

Background Art

[0002] Vehicles such as automobiles have a power unit incorporating an electric motor (see Patent Documents 1-3). Further, the electric motor in the power unit has an oil cooling structure that cools the stator with oil.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0004] By supplying the oil in the power unit to a heat exchanger, it is conceivable to warm devices such as a battery pack through the heat exchanger. For example, in an extremely low temperature environment, it is conceivable to actively warm the battery pack by giving thermal energy from the power unit to the battery pack through the heat exchanger to improve the charge and discharge performance. Further, when warming devices such as a battery pack using a heat exchanger, it is required to warm the oil in the power unit early.

Means for Solving the Problems

[0005] According to this disclosure, a vehicle drive system has a heat exchanger comprising a first heat exchange passage through which oil is guided and a second heat exchange passage through which a heat transfer medium is guided. The vehicle drive system has a power unit comprising a housing connected to the first heat exchange passage and an electric motor housed in the housing. The power unit comprises an oil supply passage connected to the input port of the first heat exchange passage and supplying oil from the housing to the heat exchanger, and an oil return passage connected to the output port of the first heat exchange passage and returning oil from the heat exchanger to the housing. The power unit comprises a first oil jacket connected to the oil return passage and covering the stator end face of the electric motor, and a second oil jacket connected to the oil return passage and covering the outer circumferential surface of the stator of the electric motor. The power unit comprises an on / off valve provided in a connecting passage that connects the oil return passage and the second oil jacket to each other, which operates to open the connecting passage and to close the connecting passage. The on / off valve operates in an open state when the internal pressure of the oil return passage exceeds a threshold, and operates in a closed state when the internal pressure of the oil return passage falls below the threshold. [Effects of the Invention]

[0006] According to this disclosure, by operating the on / off valve to the closed position, the oil in the power unit can be warmed up quickly. [Brief explanation of the drawing]

[0007] [Figure 1] Figure 1 shows a vehicle equipped with a vehicle drive system, which is one embodiment of the present disclosure. [Figure 2] Figure 2 shows the status of the battery cooling mode. [Figure 3] Figure 3 shows the status of the battery heating mode. [Figure 4] Figure 4 shows an example of the basic structure of an electronic control unit. [Figure 5]Figure 5 shows an example of an electric axle and heat exchanger included in a vehicle drive system. [Figure 6A] Figure 6A is a cross-sectional view showing the electric axle along the line 6A-6A in Figure 5. [Figure 6B] Figure 6B is a cross-sectional view showing the electric axle along the line 6B-6B in Figure 5. [Figure 7] Figure 7 shows the oil flow within the electric axle in low discharge mode. [Figure 8A] Figure 8A is a cross-sectional view showing the electric axle along the line 8A-8A in Figure 7. [Figure 8B] Figure 8B is a cross-sectional view showing the electric axle along the line 8B-8B in Figure 7. [Figure 9] Figure 9 shows the oil flow within the electric axle in high discharge mode. [Figure 10] Figure 10 is a cross-sectional view showing the electric axle along line 10-10 in Figure 9. [Figure 11] Figure 11 is a flowchart showing an example of the procedure for performing battery heating control. [Figure 12] Figure 12 shows a modified example of a vehicle drive system. [Figure 13] Figure 13 is a flowchart showing an example of the procedure for performing heater core heating control. [Modes for carrying out the invention]

[0008] Embodiments of this disclosure will be described in detail below with reference to the drawings. In the following description, identical or substantially identical components and elements will be denoted by the same reference numerals, and repeated descriptions will be omitted.

[0009] <Vehicle> FIG. 1 is a diagram showing a vehicle 11 equipped with a vehicle drive device 10 according to an embodiment of the present disclosure. As shown in FIG. 1, the vehicle 11 includes an electric axle (power unit) 14 composed of an electric motor 12 and a differential 13, and a battery pack 16 connected to the electric axle 14 via an inverter 15. A motor control unit 17, which is an electronic control unit, executes switching control of the inverter 15 and controls the torque and rotational speed of the electric motor 12. Note that the differential 13 of the electric axle 14 is connected to a wheel 19 via an axle 18.

[0010] The battery pack 16 includes a battery module 20 composed of a plurality of battery cells, and a battery control unit 21 that monitors the charge and discharge of the battery module 20. The battery pack 16 also includes a battery sensor 22 that detects the charge and discharge current, terminal voltage, etc., and a temperature sensor 23 that detects the temperature of the battery pack 16, that is, the temperature of the battery module 20. The battery control unit 21, which is an electronic control unit, determines the temperature of the battery module 20 and calculates the state of charge (SOC) of the battery module 20.

[0011] <Temperature management system> The vehicle 11 includes a temperature management system 33 composed of a radiator 30, a switching valve 31, a heat exchanger 32, etc. The radiator 30 and the switching valve 31 are connected to each other via connection pipes 35a and 35b, and the battery pack 16 and the switching valve 31 are connected to each other via connection pipes 36a and 36b. The heat exchanger 32 and the switching valve 31 are connected to each other via connection pipes 37a and 37b, and the heat exchanger 32 and the electric axle 14 are connected to each other via connection pipes 38a and 38b.

[0012] The valve body 31a of the switching valve 31 is operable between a cooling position that allows the connecting pipes 35a, 35b, 36a, and 36b to communicate with each other and a heating position that allows the connecting pipes 36a, 36b, 37a, and 37b to communicate with each other. By operating the valve body 31a of the switching valve 31 to the cooling position, the battery pack 16 can be connected to the radiator 30. Also, by operating the valve body 31a of the switching valve 31 to the heating position, the battery pack 16 can be connected to the heat exchanger 32.

[0013] The temperature management system 33 includes a water pump 40 provided in the connecting pipe 36a and an oil pump 41 provided in the electric axle 14. The water pump 40 is an electric water pump driven by an electric motor (not shown), and the oil pump 41 is an electric oil pump driven by an electric motor (not shown). Also, the temperature management system 33 includes a temperature control unit 42 which is an electronic control unit. The temperature control unit 42 outputs control signals to the switching valve 31, the water pump 40, the oil pump 41, etc., and operates the temperature management system 33 to control the battery pack 16 within a predetermined temperature range.

[0014] As shown in the enlarged portion of FIG. 1, the heat exchanger 32 includes a heat exchange flow path (first heat exchange flow path) 51 to which the connecting pipes 38a and 38b are connected, and a heat exchange flow path (second heat exchange flow path) 52 to which the connecting pipes 37a and 37b are connected. That is, the connecting pipe 38a is connected to the input port 51a of the heat exchange flow path 51, and the connecting pipe 38b is connected to the output port 51b of the heat exchange flow path 51. Also, the connecting pipe 37a is connected to the input port 52a of the heat exchange flow path 52, and the connecting pipe 37b is connected to the output port 52b of the heat exchange flow path 52. The connecting pipes 35a, 35b, 36a, 36b, 37a, 37b, and the heat exchange flow path 52 are filled with a coolant for cooling the battery pack 16. Also, the connecting pipes 38a, 38b, and the heat exchange flow path 51 are filled with oil supplied from the electric axle 14.

[0015] <Battery Cooling Mode, Battery Heating Mode> The battery cooling mode and battery heating mode, which are control modes of the temperature management system 33, will now be described. Here, Figure 2 shows the execution status of the battery cooling mode, and Figure 3 shows the execution status of the battery heating mode. The battery cooling mode, which cools the battery pack 16, is a control mode that operates the valve body 31a of the switching valve 31 to the cooling position, and is executed, for example, when the temperature of the battery pack 16 exceeds a predetermined high-temperature threshold. The battery heating mode, which warms the battery pack 16, is a control mode that operates the valve body 31a of the switching valve 31 to the heating position, and is executed, for example, when the temperature of the battery pack 16 falls below a predetermined low-temperature threshold.

[0016] As shown in Figure 2, when the temperature control unit 42 executes the battery cooling mode, it moves the valve body 31a of the switching valve 31 to the cooling position and drives the water pump 40. In other words, by moving the valve body 31a of the switching valve 31 to the cooling position, the cooling passage (heat transfer medium passage) 16a provided in the battery pack 16 is connected to the radiator 30 via connecting pipes 35a, 35b, 36a, and 36b. Furthermore, since the water pump 40 is driven, as indicated by arrow FL1, the coolant (heat transfer medium) can be circulated between the battery pack 16 and the radiator 30, and the battery pack 16 can be controlled to an appropriate temperature range.

[0017] Furthermore, the cooling channel 16a of the battery pack 16 is configured to guide coolant between battery cells (not shown) in order to cool the battery cells in the battery module 20. Also, since the oil in the electric axle 14 is used for cooling and lubrication, the oil pump 41 is driven according to the operating state of the electric axle 14. In other words, even in the battery cooling mode when the heat exchanger 32 is disconnected from the battery pack 16, oil circulates between the electric axle 14 and the heat exchanger 32, as shown by the arrow FL2 in Figure 2.

[0018] As shown in Figure 3, when the temperature control unit 42 executes the battery heating mode, it moves the valve body 31a of the switching valve 31 to the heating position and drives the water pump 40 and the oil pump 41. As a result, coolant circulates between the battery pack 16 and the heat exchanger 32, as indicated by arrow FL3, and oil circulates between the electric axle 14 and the heat exchanger 32, as indicated by arrow FL2.

[0019] In other words, the coolant flowing through the battery pack 16 is guided to the heat exchanger 32, and the oil heated in the electric axle 14 is also guided to the heat exchanger 32. This allows thermal energy to be supplied from the electric axle 14 to the battery pack 16 via the heat exchanger 32, thereby actively warming the battery pack 16. Thus, in battery heating mode, the coolant flowing through the cooling channel 16a of the battery pack 16 functions as a heat transfer medium for warming the battery pack 16.

[0020] <External charging system> As shown in Figure 1, the vehicle 11 has an external charging system 62 consisting of an onboard charger 60 and a charging inlet 61. The onboard charger 60 is connected to the battery pack 16 via power cables 63p and 63n. The charging inlet 61 is also connected to the onboard charger 60 via power cables 64p and 64n. Thus, the charging inlet 61 is connected to the battery pack 16 via the onboard charger 60, which is a power conversion device. In addition, a charging connector 67 for a charging cable 66 connected to an external power source 65 is detachably attached to the charging inlet 61 of the vehicle 11.

[0021] The external charging system 62 includes a charging control unit 68, which is an electronic control unit. When the user connects the charging connector 67 to the charging inlet 61 and performs a predetermined operation to start external charging, the charging control unit 68 outputs a control signal to the onboard charger 60. As a result, the onboard charger 60 converts the AC power from the external power source 65 to DC power, and the onboard charger 60 supplies DC power to the battery pack 16. In this way, the charging control unit 68 outputs a control signal to the onboard charger 60 and controls the operating state of the external charging system 62.

[0022] <Control System> As shown in Figure 1, the vehicle 11 has a control system 70 consisting of multiple electronic control units. The electronic control units that make up the control system 70 include the motor control unit 17, battery control unit 21, temperature control unit 42, and charging control unit 68 mentioned above. In addition, the vehicle control unit 71 that outputs control signals to each of the aforementioned control units 17, 21, 42, and 68 also makes up the control system 70.

[0023] These control units 17, 21, 42, 68, and 71 are connected to each other via an in-vehicle network 72 so that they can communicate with one another. The vehicle control unit 71 sets operating targets for the temperature management system 33 and the external charging system 62 based on input information from the various control units 17, 21, 42, 68 and various sensors described later. The vehicle control unit 71 also generates control signals according to the operating targets for the temperature management system 33, etc., and outputs these control signals to the various control units 17, 21, 42, and 68.

[0024] Sensors connected to the vehicle control unit 71 include a vehicle speed sensor 73 for detecting the vehicle speed, which is the travel speed of the vehicle 11; an accelerator sensor 74 for detecting the accelerator pedal opening, which is the amount the accelerator pedal is operated; and a brake sensor 75 for detecting the amount the brake pedal is operated. Sensors connected to the vehicle control unit 71 include a rotational speed sensor 76 for detecting the rotational speed of the oil pump 41; a temperature sensor 77 for detecting the temperature of the oil circulating in the electric axle 14; and a temperature sensor 78 for detecting the temperature of the coolant circulating in the battery pack 16. Furthermore, the vehicle control unit 71 is connected to a start switch 79 which is operated by the driver when starting the control system 70.

[0025] Figure 4 shows an example of the basic structure of the electronic control units 17, 21, 42, 68, and 71. As shown in Figure 4, the electronic control units 17, 21, 42, 68, and 71 have a microcontroller 82 into which a processor 80 and main memory (memory) 81 are incorporated. A predetermined program is stored in the main memory 81, and the program is executed by the processor 80. The processor 80 and the main memory 81 are connected to each other so as to be able to communicate with each other. Note that the microcontroller 82 may incorporate multiple processors 80, and the microcontroller 82 may also incorporate multiple main memory 81.

[0026] The electronic control units 17, 21, 42, 68, and 71 each have an input circuit 83, a drive circuit 84, a communication circuit 85, an external memory 86, and a power supply circuit 87. The input circuit 83 converts signals input from various sensors into signals that can be input to the microcontroller 82. The drive circuit 84 generates drive signals for devices such as the inverter 15 and the on-board charger 60 based on signals output from the microcontroller 82. The communication circuit 85 converts signals output from the microcontroller 82 into communication signals for other electronic control units, etc. The communication circuit 85 also converts communication signals received from other electronic control units, etc., into signals that can be input to the microcontroller 82. Furthermore, the power supply circuit 87 supplies power voltage to the microcontroller 82, input circuit 83, drive circuit 84, communication circuit 85, and external memory 86, etc. In addition, the external memory 86, which consists of non-volatile memory, stores programs and various data.

[0027] <Electric Axle> The structure of the electric axle 14 will be described in detail below. Figure 5 shows an example of the electric axle 14 and heat exchanger 32 provided in the vehicle drive unit 10. Figure 6A is a cross-sectional view showing the electric axle 14 along the line 6A-6A in Figure 5, and Figure 6B is a cross-sectional view showing the electric axle 14 along the line 6B-6B in Figure 5.

[0028] As shown in Figure 5, the electric axle 14 has a housing 93 that includes a motor housing 90, a gear housing 91, and a pump housing 92. The housing 93 stores oil L used for lubrication and cooling. The motor housing 90 houses the electric motor 12, the gear housing 91 houses the reduction gear train 94 and the differential 13, and the pump housing 92 houses an oil supply passage 95 equipped with an oil pump 41. The motor housing 90 of the housing 93 is partitioned by a sleeve wall 96 surrounding the electric motor 12, a partition wall 97 connected to one end of the sleeve wall 96, and a partition wall 98 connected to the other end of the sleeve wall 96. The motor housing 90 and the gear housing 91 are separated by partition wall 97, and the motor housing 90 and the pump housing 92 are separated by partition wall 98.

[0029] The electric motor 12 housed in the housing 93 comprises a stator 102 consisting of a stator core 100 and stator coils 101, and a rotor 105 consisting of a rotor core 103 and permanent magnets 104. The stator 102 includes coil ends 106 of the stator coils 101 protruding from one end face of the stator core 100, and coil ends 107 of the stator coils 101 protruding from the other end face of the stator core 100. The rotor shaft 108, fixed to the rotor core 103, is rotatably supported by partition walls 97 and 98 via bearings 109 and 110. Furthermore, the stator core 100 is fixed to the sleeve wall 96 via bolts (not shown).

[0030] Two seal rings 111 and 112 are installed between the inner surface of the sleeve wall 96 and the outer surface of the stator 102. Two seal rings 113 and 114 are installed between the inner surface of the stator 102 and the outer surface of the rotor 105. In this way, by incorporating the seal rings 111 to 114 into the motor housing chamber 90, multiple oil jackets 120, 121, and 122 are partitioned within the motor housing chamber 90. Specifically, the motor housing chamber 90 is partitioned into a side jacket (first oil jacket) 120 that covers one end face (stator end face) 102a of the stator 102, and a side jacket (first oil jacket) 121 that covers the other end face (stator end face) 102b of the stator 102. In addition, the motor housing chamber 90 is partitioned into a sleeve jacket (second oil jacket) 122 that covers the outer surface (stator outer surface) 102c of the stator 102.

[0031] As shown in Figures 5, 6A, and 6B, an oil return passage 123 is formed in the upper part of the sleeve wall 96. This oil return passage 123 is connected to the output port 51b of the heat exchange passage 51 via a connecting pipe 38b. In addition, an inlet port 120a communicating with the side jacket 120, an inlet port 121a communicating with the side jacket 121, and an inlet port 122a communicating with the sleeve jacket 122 are formed in the upper part of the sleeve wall 96. Furthermore, an outlet port 120b communicating with the side jacket 120, an outlet port 121b communicating with the side jacket 121, and an outlet port 122b communicating with the sleeve jacket 122 are formed in the lower part of the sleeve wall 96. The outlet ports 120b, 121b, and 122b formed in the lower part of the sleeve wall 96 open toward the oil pan 93a provided in the lower part of the housing 93. In other words, the discharge ports 120b, 121b, and 122b open to the inside of the housing 93.

[0032] As shown in Figures 5 and 6A, the electric axle 14 has an on / off valve 130 that opens and closes the inlet port 122a of the sleeve jacket 122. The on / off valve 130, located inside the sleeve jacket 122, comprises a valve body 131 facing the inlet port 122a and a spring 132 that biases the valve body 131 toward the inlet port 122a. When the internal pressure of the oil return passage 123 exceeds a predetermined threshold, the oil pressure causes the valve body 131 to move away from the inlet port 122a, so the on / off valve 130 operates in an open state, opening the inlet port 122a. On the other hand, when the internal pressure of the oil return passage 123 falls below a predetermined threshold, the spring force of the spring 132 causes the valve body 131 to contact the inlet port 122a, so the on / off valve 130 operates in a closed state, closing the inlet port 122a. In other words, the electric axle 14 has an on / off valve 130 provided in a connecting passage 133 that connects the oil return passage 123 and the sleeve jacket 122 to each other. This on / off valve 130 operates in an open state that opens the connecting passage 133 and a closed state that closes the connecting passage 133.

[0033] As shown in Figures 5 and 6B, the discharge port 120b of the side jacket 120 is smaller than the inlet port 120a of the side jacket 120. In other words, the flow path cross-sectional area of ​​the discharge port 120b is smaller than the flow path cross-sectional area of ​​the inlet port 120a. Similarly, the discharge port 121b of the side jacket 121 is smaller than the inlet port 121a of the side jacket 121. In other words, the flow path cross-sectional area of ​​the discharge port 121b is smaller than the flow path cross-sectional area of ​​the inlet port 121a.

[0034] As shown in Figure 5, the electric axle 14 has an oil supply channel 95 that supplies oil from the oil pan 93a of the housing 93 to the heat exchanger 32, and an oil return channel 123 that returns oil from the heat exchanger 32 to the housing 93. In other words, the oil supply channel 95 is connected to the input port 51a of the heat exchanger 32 via a connecting pipe 38a, and the oil return channel 123 is connected to the output port 51b of the heat exchanger 32 via a connecting pipe 38b. The oil supply channel 95 is composed of a strainer 134, an oil pump 41, and a supply pipe 135.

[0035] As shown in Figures 5 and 6A, the electric axle 14 has a communication passage 140 that connects the sleeve jacket 122 and the gear housing chamber 91 to each other. The electric axle 14 also has a breather port 141 that connects the inside and outside of the gear housing chamber 91. In other words, the sleeve jacket 122 and the breather port 141 are in communication with each other via the communication passage 140 and the gear housing chamber 91. That is, the sleeve jacket 122 is in communication with the outside of the housing 93 via the communication passage 140, the gear housing chamber 91 and the breather port 141.

[0036] <Low discharge mode, High discharge mode> The low-discharge mode and high-discharge mode, which are control modes of the oil pump 41, will now be described. Here, Figure 7 shows the oil flow in the electric axle 14 in the low-discharge mode. Figure 8A is a cross-sectional view of the electric axle 14 along the line 8A-8A in Figure 7, and Figure 8B is a cross-sectional view of the electric axle 14 along the line 8B-8B in Figure 7. Figure 9 shows the oil flow in the electric axle 14 in the high-discharge mode. Figure 10 is a cross-sectional view of the electric axle 14 along the line 10-10 in Figure 9. Note that cross-hatching is used to show the oil and coolant in Figures 7, 8A, 8B, 9, and 10. Also, in Figures 7 and 9, the arrows in the cross-hatching indicate the direction of oil flow.

[0037] As shown in Figure 7, when the temperature control unit 42 is running the low discharge mode, it controls the rotational speed of the oil pump 41 within a range below a predetermined threshold. By suppressing the rotational speed of the oil pump 41, i.e., the oil discharge rate, the flow rate of oil supplied from the oil pump 41 to the oil return passage 123 via the heat exchanger 32 can be reduced, and the internal pressure of the oil return passage 123 can be kept below a predetermined threshold. As a result, as shown in Figures 7 and 8A, the introduction port 122a of the sleeve jacket 122 is closed by the on / off valve 130, so no oil is supplied from the oil return passage 123 to the sleeve jacket 122, and oil is supplied only to the side jackets 120 and 121 from the oil return passage 123.

[0038] As shown in Figures 7 and 8B, the flow path cross-sectional area of ​​the discharge port 120b in the side jacket 120 is smaller than the flow path cross-sectional area of ​​the inlet port 120a. In other words, the inlet port 120a of the side jacket 120 is larger than the discharge port 120b of the side jacket 120. This means that in the side jacket 120, the amount of oil supplied is greater than the amount of oil discharged. As a result, even when the oil pump 41 is driven in low discharge mode, oil can be stored in almost the entire side jacket 120. Similarly, the flow path cross-sectional area of ​​the discharge port 121b in the side jacket 121 is smaller than the flow path cross-sectional area of ​​the inlet port 121a. In other words, the inlet port 121a of the side jacket 121 is larger than the discharge port 121b of the side jacket 121. This means that in the side jacket 121, the amount of oil supplied is greater than the amount of oil discharged. As a result, even when the oil pump 41 is driven in low discharge mode, oil can be stored in almost the entire side jacket 121.

[0039] Thus, in the low discharge mode, oil is supplied only to the side jackets 120 and 121 from the oil return passage 123, allowing the oil to be quickly heated by the coil ends 106 and 107. For example, if oil is supplied to the sleeve jacket 122 in an extremely low temperature environment, a large amount of thermal energy is transferred from the oil to the sleeve wall 96, making it difficult to quickly raise the oil temperature. In contrast, in the low discharge mode, the oil supply to the sleeve jacket 122 is cut off, allowing the oil to be quickly heated.

[0040] As shown in Figures 7 and 8A, in the low discharge mode, the lower end position X1 of the sleeve jacket 122 is located above the oil level X2. This prevents oil from flowing into the sleeve jacket 122 when the low discharge mode is executed, allowing the oil to be quickly warmed even in extremely low temperature environments. In addition, outside air is introduced into the sleeve jacket 122 from the breather port 141, so oil is discharged from the sleeve jacket 122 in the low discharge mode.

[0041] As shown in Figure 9, when the high discharge mode is executed, the temperature control unit 42 controls the rotational speed of the oil pump 41 within a range exceeding a predetermined threshold. By increasing the rotational speed of the oil pump 41 in this way and increasing the oil discharge rate, the flow rate of oil supplied from the oil pump 41 to the oil return passage 123 via the heat exchanger 32 can be increased, and the internal pressure of the oil return passage 123 can be kept above a predetermined threshold. As a result, as shown in Figures 9 and 10, the introduction port 122a of the sleeve jacket 122 is opened by the on / off valve 130, so that oil can be supplied from the oil return passage 123 to the sleeve jacket 122.

[0042] Thus, in high discharge mode, oil is supplied from the oil return passage 123 to the sleeve jacket 122 and the side jackets 120 and 121. In other words, in high discharge mode, a lot of thermal energy is transferred from the oil passing through the sleeve jacket 122 to the sleeve wall 96, so the stator 102 can be actively cooled by the oil. Furthermore, in high discharge mode, as shown by arrow α in Figure 9, oil flows from the sleeve jacket 122 to the gear housing chamber 91 via the communication passage 140, and oil is supplied to the differential 13 and the reduction gear train 94.

[0043] <Battery overheating control> Next, we will describe the battery heating control performed during external charging in an extremely low-temperature environment. Figure 11 is a flowchart showing an example of the procedure for executing battery heating control. Each step in the flowchart in Figure 11 is performed by the processor 80 that constitutes the control system 70.

[0044] As shown in Figure 11, the control system 70 proceeds to step S10 and determines whether external charging is in progress with the charging connector 67 connected to the charging inlet 61, that is, whether external charging is in progress with the battery pack 16 connected to an external power supply 65. If the control system 70 determines in step S10 that external charging is in progress, it proceeds to step S11 and determines whether the temperature of the battery pack 16 (hereinafter referred to as battery temperature) falls below a predetermined threshold TA.

[0045] If the control system 70 determines in step S11 that the battery temperature falls below the threshold TA, it proceeds to step S12 and controls the electric motor 12 in heating mode. Here, the heating mode of the electric motor 12 is a control mode in which only one phase of the stator coil 101 is energized. By executing this heating mode, the stator coil 101 of the electric motor 12 can be actively heated without rotating the rotor 105 of the electric motor 12.

[0046] The control system 70 proceeds to step S13, where it operates the valve body 31a of the switching valve 31 to the heating position, and then proceeds to step S14, where it drives the water pump 40. The control system 70 also proceeds to step S15, where it drives the oil pump 41 in low discharge mode. This shuts off the oil supply from the oil return passage 123 to the sleeve jacket 122, as shown in Figure 7, and allows the coil ends 106 and 107 to actively heat the oil. The thermal energy of the heated oil is then transferred from the heat exchanger 32 to the battery pack 16 via the coolant. In this way, by heating the battery pack 16 with the oil from the electric axle 14, the internal resistance of the battery pack 16 can be reduced, allowing the battery pack 16 to be charged efficiently even in extremely low temperature environments.

[0047] On the other hand, if the control system 70 determines in step S11 that the battery temperature is above the threshold TA, it proceeds to steps S16, S17, and S18, and stops the electric motor 12, water pump 40, and oil pump 41. In other words, if the battery temperature is at the expected temperature for external charging, external charging of the battery pack 16 using the external power supply 65 is performed without operating the electric motor 12, water pump 40, and oil pump 41.

[0048] In the above explanation, the oil pump 41 is controlled in low discharge mode during external charging, but this is not the only option. The oil pump 41 may also be controlled in low discharge mode when the vehicle is running in an extremely low temperature environment. In other words, the control system 70 may operate the valve body 31a of the switching valve 31 to the heating position when the battery temperature falls below the threshold TA, drive the water pump 40, and drive the oil pump 41 in low discharge mode. This allows the battery pack 16 to be actively warmed by the oil in the electric axle 14, thereby lowering the internal resistance of the battery pack 16 in an extremely low temperature environment and improving the output characteristics during charging and discharging.

[0049] <Example 1> In the examples shown in Figures 2 and 3, the battery pack 16 is connected to the heat exchanger 32 via a switching valve 31, but this is not the only option, and other devices besides the battery pack 16 may be connected to the heat exchanger 32. Here, Figure 12 shows a modified vehicle drive unit 150. In Figure 12, components and elements similar to those shown in Figure 2 are denoted by the same reference numerals and their descriptions are omitted.

[0050] As shown in Figure 12, the vehicle drive unit 150 has an air conditioning unit 153 consisting of a heater core 151 and a blower 152, etc. The heat exchange passage 52 of the heat exchanger 32 and the heat exchange passage 154 of the heater core 151 are connected to each other via connecting pipes 155a and 155b. A circulation pump 156 for pressurizing the circulating fluid (heat transfer medium) is also provided in the connecting pipe 155a. By driving the circulation pump 156 and the oil pump 41, the circulating fluid is circulated between the heater core 151 and the heat exchanger 32, as shown by arrow FL4, and oil is circulated between the electric axle 14 and the heat exchanger 32, as shown by arrow FL5. This allows thermal energy to be supplied from the electric axle 14 to the heater core 151 via the heat exchanger 32, and the heater core 151 can be actively heated by the oil in the electric axle 14.

[0051] <Heater core heating control> This section describes heater core heating control performed during vehicle cabin heating. Figure 13 is a flowchart showing an example of the procedure for performing heater core heating control. Each step in the flowchart in Figure 13 is performed by the processor 80 that constitutes the control system 70.

[0052] As shown in Figure 13, the control system 70 proceeds to step S20 to determine whether or not the cabin heating is in progress and the heater core 151 is activated. If the control system 70 determines in step S20 that the cabin heating is in progress, it proceeds to step S21 to determine whether or not the vehicle 11 is stopped. If the control system 70 determines in step S21 that the vehicle is stopped, it proceeds to step S22 to control the electric motor 12 in heating mode, proceeds to step S23 to drive the circulation pump, and proceeds to step S24 to drive the oil pump 41 in low discharge mode.

[0053] Meanwhile, if the control system 70 determines in step S21 that the vehicle is in motion, it proceeds to step S25 and determines whether the temperature of the circulating fluid flowing through the heater core 151 (hereinafter referred to as the circulating fluid temperature) falls below a predetermined threshold TB. If the control system 70 determines in step S25 that the circulating fluid temperature falls below the threshold TB, it proceeds to step S26 and drives the electric motor 12 according to the accelerator opening, etc. The control system 70 also proceeds to step S27 to drive the circulation pump, and then to step S28 to drive the oil pump 41 in low discharge mode.

[0054] Thus, when the vehicle is stationary or the circulating fluid temperature is low, the oil pump 41 is driven in low discharge mode. As a result, as shown in Figure 7, the oil supply from the oil return passage 123 to the sleeve jacket 122 can be shut off, and the coil ends 106 and 107 can actively heat the oil. The thermal energy of the heated oil is then transferred from the heat exchanger 32 to the heater core 151 via the circulating fluid. In this way, by quickly heating the oil in the electric axle 14, the heater core 151 can be heated quickly even in an extremely low temperature environment.

[0055] As shown in Figure 13, when the control system 70 determines in step S25 that the circulating fluid temperature is above the threshold TB, it proceeds to step S29 and drives the electric motor 12 according to the accelerator opening, etc. The control system 70 also proceeds to step S30 to drive the circulation pump, and then to step S31 to drive the oil pump 41 in high discharge mode. In this way, when the circulating fluid temperature is high, that is, when the heater core 151 is sufficiently warm, the oil pump 41 is driven in high discharge mode, and as shown in Figure 9, the introduction port 122a of the sleeve jacket 122 is opened and the electric motor 12 is actively cooled.

[0056] <Other variations> This disclosure is not limited to the embodiments described above, and it goes without saying that various modifications are possible without departing from the gist of the disclosure. In the illustrated example, the housing 93 is provided with two side jackets 120 and 121, but this is not limited to this, and the housing 93 may be provided with only one of the side jackets 120 and 121. In the above description, an on-off valve 130 that is opened and closed by the pressure applied to the valve body 131 is used, but this is not limited to this, and an on-off valve that is opened and closed by electromagnetic force may be used. In the above description, when the heating mode of the electric motor 12 is executed, only one phase of the stator coil 101 is energized, but this is not limited to this. For example, the three phases of the stator coil 101 may be energized while the electric motor 12 is in a brake state.

[0057] In the illustrated example, an electric axle 14 that drives the rear wheel 19 is used as the power unit, but it is not limited to this. For example, it may be a power unit that drives the front wheel, or a power unit that drives both the front and rear wheels. In the illustrated example, the control system 70 is composed of multiple electronic control units 17, 21, 42, 68, and 71, but it is not limited to this, and the control system 70 may be composed of a single electronic control unit. In the illustrated example, the heat exchanger 32 is connected to the housing 93 via connecting pipes 38a and 38b, but it is not limited to this, and the heat exchanger 32 and the housing 93 may be connected directly. [Explanation of symbols]

[0058] 10...Vehicle drive unit, 12...Electric motor, 14...Electric axle (power unit), 16...Battery pack, 16a...Cooling passage (heat transfer passage), 32...Heat exchanger, 41...Oil pump, 51...Heat exchange passage (first heat exchange passage), 51a...Input port, 51b...Output port, 52...Heat exchange passage (second heat exchange passage), 65...External power supply, 70...Control system, 80...Processor, 81...Main memory (memory), 93...Housing, 95...Oil supply passage, 102a...One end face (stay) 102b…Other end face (stator end face), 102c…Outer circumference (stator outer circumference), 120…Side jacket (first oil jacket), 120a…Inlet port, 120b…Discharge port, 121…Side jacket (first oil jacket), 121a…Inlet port, 121b…Discharge port, 122…Sleeve jacket (second oil jacket), 123…Oil return passage, 130…On / off valve, 133…Connecting passage, 141…Breather port, 150…Vehicle drive system

Claims

1. A heat exchanger comprising a first heat exchange channel through which oil is guided, and a second heat exchange channel through which a heat transfer medium is guided, A power unit comprising a housing connected to the first heat exchange channel, and an electric motor housed in the housing, It has, The aforementioned power unit is An oil supply channel connected to the input port of the first heat exchange channel, which supplies oil from the housing to the heat exchanger, An oil return channel connected to the output port of the first heat exchange channel, which returns oil from the heat exchanger to the housing, A first oil jacket connected to the oil return passage and covering the stator end face of the electric motor, A second oil jacket connected to the aforementioned oil return passage and covering the outer surface of the stator of the electric motor, A connecting passage is provided in the connecting passage that connects the oil return passage and the second oil jacket to each other, and an on / off valve is provided that operates to open the connecting passage and to close the connecting passage, Equipped with, The on / off valve operates in an open state when the internal pressure of the oil return passage exceeds a threshold, and operates in a closed state when the internal pressure of the oil return passage falls below the threshold. Vehicle drive system.

2. In the vehicle drive system according to claim 1, The heat transfer medium channel of the battery pack is connected to the second heat exchange channel. Vehicle drive system.

3. In the vehicle drive system according to claim 2, An oil pump provided in the aforementioned oil supply passage, A control system comprising a processor and memory connected to each other in a manner that enables communication, It has, The control system controls the oil pump with an oil discharge amount that activates the on / off valve to the closed state when an external power supply is connected to the battery pack and the temperature of the battery pack falls below a threshold. Vehicle drive system.

4. In the vehicle drive system according to claim 1, The first oil jacket comprises an inlet port communicating with the oil return passage and a discharge port opening to the inside of the housing, The cross-sectional area of ​​the flow path of the discharge port is smaller than the cross-sectional area of ​​the flow path of the inlet port. Vehicle drive system.

5. In the vehicle drive system according to claim 1, The second oil jacket is in communication with the breather port. Vehicle drive system.

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