Vehicle control device

Abstract

To provide a vehicle control device that can ensure the withstand voltage of a device, to which the electric power generated by an electric motor is supplied, and can suppress deterioration of power performance during evacuation traveling using an engine.SOLUTION: A vehicle 10 comprises an engine 12, an automatic transmission 28, an electric motor MG that is dragged to rotate in a non-driving state during evacuation traveling using the engine 12, and a relay 62 that connects and disconnects the electric motor MG and a main battery 60. An electronic control unit 100: (a) disconnects the relay 62 based on a predetermined vehicle state, puts the electric motor MG in a non-driving state, and performs evacuation traveling using the engine 12; (b) during the evacuation traveling, calculates the upper limit value Nmg_up of an electric motor rotation speed Nmg based on a stator coil temperature THcoil and a withstand voltage Vws of an air conditioner AC; and (c) during the evacuation traveling, sets an upshift point of the automatic transmission 28 so that the electric motor rotation speed Nmg does not exceed the upper limit value Nmg_up.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a control device for a vehicle that includes an engine as a power source for driving, an automatic transmission provided in a power transmission path between the engine and a pair of drive wheels, and an electric motor that is composed of a permanent magnet motor generator and is rotated when the motor generator is not driven while the vehicle is running using the engine. [Background technology]

[0002] There are known control devices for vehicles that include an engine as a power source for driving, an automatic transmission provided in a power transmission path between the engine and a pair of drive wheels, and an electric motor formed by a permanent magnet motor generator that is rotated when the motor generator is not driven while the vehicle is running using the engine. For example, the control device described in Patent Document 1 is one such device. In the control device described in Patent Document 1, during evacuation running using the engine, the automatic transmission upshifts when the rotational speed of the electric motor reaches or exceeds a predetermined fixed value in order to ensure a withstand voltage for devices supplied with power generated by the electric motor. In other words, the upshift point at which the upshift is performed is set based on the predetermined fixed value of the rotational speed of the electric motor. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2023-121351 Summary of the Invention [Problem to be solved by the invention]

[0004] When the upshift point is set based on a predetermined fixed value, it may be possible to ensure the withstand voltage of the aforementioned devices even if the upshift point is set at a higher rotational speed. In such cases, the upshift point is set lower than normal, resulting in a lack of driving force and preventing the vehicle from achieving the power performance that would have been achieved.

[0005] The present invention has been made against the background of the above circumstances, and its purpose is to provide a vehicle control device that can ensure the voltage resistance of equipment supplied with power generated by an electric motor and suppress a decrease in power performance during evacuation driving using the engine. [Means for solving the problem]

[0006] The gist of the present invention is a control device for a vehicle that includes an engine as a power source for driving, an automatic transmission provided in a power transmission path between the engine and a pair of drive wheels, an electric motor consisting of a permanent magnet motor generator that is rotated when the engine is not driven while driving using the engine, a battery that supplies and receives power to the electric motor, and a relay that disconnects the electric motor from the battery, wherein the control device (a) disconnects the relay based on a predetermined vehicle state, puts the electric motor in a non-driven state, and performs evacuation driving using the engine, (b) calculates an upper limit value for the rotational speed of the electric motor based on the temperature of the stator coil of the electric motor and the withstand voltage of equipment to which the power generated by the electric motor is supplied, and (c) sets an upshift point of the automatic transmission so that the rotational speed of the electric motor does not exceed the upper limit value during the evacuation driving. [Effects of the Invention]

[0007] According to the control device of the present invention, (a) the relay is disconnected based on a predetermined vehicle state, the electric motor is put into a non-driven state, and evacuation travel is performed using the engine; (b) during the evacuation travel, an upper limit of the rotational speed of the electric motor is calculated based on the temperature of the stator coil of the electric motor and the withstand voltage of the equipment to which electric power generated by the electric motor is supplied; and (c) during the evacuation travel, an upshift point of the automatic transmission is set so that the rotational speed of the electric motor does not exceed the upper limit. In this way, the upper limit of the rotational speed of the electric motor and the upshift point are set based on the temperature of the stator coil of the electric motor and the withstand voltage of the equipment. Therefore, compared to when the upshift point is set based on no temperature of the stator coil, the upshift point can be set to a higher rotational speed while ensuring the withstand voltage of the equipment to which electric power generated by the electric motor is supplied. This ensures the withstand voltage of the equipment to which electric power generated by the electric motor is supplied and suppresses a decrease in power performance during evacuation travel using the engine. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a schematic configuration diagram of a vehicle equipped with an electronic control device according to an embodiment of the present invention, and is also a functional block diagram showing the main parts of control functions for various controls in the vehicle. [Figure 2] 10A and 10B are diagrams illustrating the relationship between the stator coil temperature and the rotation speed of the electric motor, and the back electromotive force generated by the electric motor during evacuation running. [Figure 3] 2 is an example of a flowchart illustrating a control operation of the electronic control device shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that in the embodiments, the drawings are appropriately simplified or modified, and the dimensional ratios and shapes of the various parts are not necessarily drawn accurately. [Example]

[0010] FIG. 1 is a schematic diagram of a vehicle 10 equipped with an electronic control device 100 according to an embodiment of the present invention, and is also a functional block diagram showing the main parts of control functions for various controls in the vehicle 10.

[0011] The vehicle 10 includes an engine 12 and an electric motor MG as power sources for traveling, and a power transmission device 16 provided in a power transmission path between the engine 12 and a pair of drive wheels 14. The vehicle 10 also includes an inverter 52, a hydraulic control circuit 54, an EOP 56 which is an electric oil pump, a main battery 60, a system main relay 62 (hereinafter simply referred to as "relay 62"), an auxiliary battery 66, a DC / DC converter 68, a starter motor 70, an alternator 72, and an electronic control device 100.

[0012] The engine 12 is a well-known internal combustion engine. The electric motor MG is a permanent magnet motor generator, such as a three-phase synchronous motor. The electric motor MG includes a stator wound with a stator coil and a rotor provided with a surface magnet or embedded magnet permanent magnet.

[0013] The power transmission device 16 includes, in order from the engine 12 side, an engine connecting shaft 20, a clutch K0, a rotor shaft 22 non-rotatably connected to the rotor of the electric motor MG, a torque converter 24, an input shaft 26, and an automatic transmission 28, all of which are well-known components, housed within a case 18, which is a non-rotating member. The power transmission device 16 also includes, in order from the automatic transmission 28 side, an output shaft 30, a differential 32, and a pair of axles 34, all of which are well-known components. The automatic transmission 28 is a well-known automatic transmission that changes the speed of driving power input from the engine 12 and the electric motor MG and outputs the power. The automatic transmission 28 is controlled by a hydraulic control circuit 54, which is controlled by an electronic control unit 100, so as to form a desired gear ratio γat (= input shaft rotation speed Nin [rpm] / output shaft rotation speed Nout [rpm]) from among different gear ratios. The input shaft rotation speed Nin is the rotation speed of the input shaft 26, and the output shaft rotation speed Nout is the rotation speed of the output shaft 30. In this specification, unless otherwise specified, the terms driving force, power, force (= power), and torque are synonymous.

[0014] The inverter 52 is a power supply circuit that is provided between the electric motor MG and the main battery 60 and that converts direct current to alternating current and vice versa under the control of the electronic control device 100. For example, the inverter 52 converts direct current supplied from the main battery 60 into alternating current and outputs the alternating current to the electric motor MG, or converts alternating current generated by the electric motor MG into direct current and outputs the direct current to the main battery 60.

[0015] The starter motor 70 is a motor of known construction that starts the engine 12. The alternator 72 is a known alternator that generates electricity using the power of the engine 12. The electric power generated by the alternator 72 is charged into the auxiliary battery 66.

[0016] The main battery 60 is a rechargeable secondary battery, such as a lithium-ion battery or a nickel-metal hydride battery. The main battery 60 is a high-voltage battery that is mainly used to supply power for driving the electric motor MG and to charge the electric power generated by the electric motor MG through regeneration. The auxiliary battery 66 is a rechargeable secondary battery, such as a lead-acid battery or a lithium-ion battery. The auxiliary battery 66 is a low-voltage battery that is mainly used to supply power to the auxiliary devices (e.g., devices necessary for controlling the operation of the engine 12, including the starter motor 70 and the engine control device 50). Due to the difference in usage, the main battery 60 has a higher battery voltage Vbat [V] than the auxiliary battery 66. For example, the auxiliary battery 66 has a voltage of 12 [V], while the main battery 60 has a higher voltage. The main battery 60 corresponds to the "battery" in this invention.

[0017] The main battery 60 is connected to the inverter 52 via a relay 62. The relay 62 is, for example, a mechanical relay that is switched between an open state (disconnected state) and a closed state (connected state) by the electronic control device 100. When the relay 62 is in the closed state, power can be exchanged between the main battery 60 and the inverter 52. When the relay 62 is in the open state, power cannot be exchanged between the main battery 60 and the inverter 52.

[0018] DC / DC converter 68 is provided between a power line 64 connecting inverter 52 and relay 62 and auxiliary battery 66. DC / DC converter 68 is a power supply circuit that boosts and lowers the voltage of direct current. For example, DC / DC converter 68 lowers the voltage supplied from main battery 60 to power line 64 to charge auxiliary battery 66 with direct current having a lower voltage than that of main battery 60, or boosts the direct current supplied from auxiliary battery 66 to output direct current having a higher voltage than that of auxiliary battery 66 to power line 64. Air conditioner AC is connected to power line 64 and is supplied with power from power line 64.

[0019] The MOP 42 is a well-known mechanical oil pump that is connected to, for example, a pump impeller of the torque converter 24 and driven by at least one of the engine 12 and the electric motor MG. The EOP 56 is a well-known oil pump that can be driven by the rotation of an EOP drive motor 58, independently of the rotation of the engine 12 and the electric motor MG.

[0020] The hydraulic control circuit 54 uses the hydraulic pressure of the hydraulic oil (lubricating oil, cooling oil) OIL discharged from the MOP 42 and the EOP 56 as the source pressure and supplies the necessary hydraulic oil OIL to each part within the case 18. For example, the hydraulic control circuit 54 generates hydraulic pressure for controlling the engagement and disengagement of the clutch K0, hydraulic pressure for controlling the shifting of the automatic transmission 28, and hydraulic pressure for controlling the engagement and disengagement of the lock-up clutch LU of the torque converter 24, and supplies these to each hydraulic actuator within the case 18. The hydraulic control circuit 54 also controls the amount of lubricating oil (cooling oil) OIL supplied to supply the lubricating oil into the case 18.

[0021] The vehicle 10 can select one of three driving modes: a BEV driving mode, an engine driving mode, and an HEV driving mode. The BEV driving mode is a driving mode in which the engine 12 is stopped and the electric motor MG is powered, thereby performing BEV (Battery Electric Vehicle) driving using only the electric motor MG as a power source. The engine driving mode is a driving mode in which the clutch K0 is engaged and the engine 12 is used as a power source. In the engine driving mode, the electric motor MG is in a non-driving state, and the rotor shaft 22 of the electric motor MG is rotated by the engine 12. The HEV driving mode is a driving mode in which the clutch K0 is engaged and the HEV (Hybrid Electric Vehicle) driving is performed using both the engine 12 and the electric motor MG as power sources. Note that driving in the engine driving mode corresponds to "driving using the engine" in this invention.

[0022] The electronic control unit 100 includes, for example, a so-called microcomputer, and performs signal processing in accordance with pre-stored programs to execute various controls of the vehicle 10. The electronic control unit 100 corresponds to the "control unit" of the present invention.

[0023] The electronic control device 100 receives inputs of various signals based on detection values ​​from various sensors provided on the vehicle 10 (e.g., an engine rotation speed sensor 80, an input shaft rotation speed sensor 82, an output shaft rotation speed sensor 84, an electric motor rotation speed sensor 86, an accelerator opening sensor 88, a throttle valve opening sensor 90, a battery sensor 92, a temperature sensor 94, etc.) (e.g., an engine rotation speed Ne [rpm] which is the rotation speed of the engine 12, an input shaft rotation speed Nin, an output shaft rotation speed Nout corresponding to the vehicle speed V [km / h], an electric motor rotation speed Nmg [rpm] which is the rotation speed of the electric motor MG, an accelerator opening θacc [%] which is the driver's accelerator operation amount which indicates the magnitude of the driver's acceleration operation, a throttle valve opening θth [%] which is the opening of the electronic throttle valve, a battery temperature THbat [°C], a battery charge / discharge current Ibat [A] and a battery voltage Vbat of the main battery 60, and a stator coil temperature THcoil [°C] which is the temperature of the stator coil of the electric motor MG).

[0024] The electronic control device 100 outputs various command signals (e.g., an engine control signal Se for controlling the operation of the engine 12, an electric motor control signal Smg for controlling the operation of the electric motor MG, a shift control signal Sat for controlling the shift of the automatic transmission 28, a K0 control signal Sk0 for controlling the connection and disconnection of the clutch K0, an LU control signal Slu for controlling the connection and disconnection of the lock-up clutch LU of the torque converter 24, an EOP control signal Seop for controlling the operation of the EOP 56, a relay control signal Ssmr for controlling the opening and closing of the relay 62, a converter control signal Scon for controlling the voltage conversion of the DC / DC converter 68, etc.) to each device provided in the vehicle 10 (e.g., an engine control device 50, an inverter 52, a hydraulic control circuit 54, an EOP drive motor 58, a relay 62, a DC / DC converter 68, etc.).

[0025] The electronic control device 100 functionally comprises a power source control unit 102, a transmission control unit 104, a clutch control unit 106, a torque converter control unit 108, a relay control unit 110, a converter control unit 112, an abnormality determination unit 114, an upper limit value calculation unit 116, and a shift point setting unit 118.

[0026] The power source control unit 102 functionally includes an engine control unit 102 a that controls the operation of the engine 12 , and an electric motor control unit 102 b that controls the operation of the electric motor MG via the inverter 52 .

[0027] The power source control unit 102 calculates the required drive torque Trdem by applying the actual accelerator opening θacc and vehicle speed V to a map in which the relationship between the accelerator opening θacc, vehicle speed V, and the required drive torque Trdem [N·m] is determined in advance experimentally or by design and stored. The power source control unit 102 takes into consideration factors such as transmission loss, the auxiliary load, the gear ratio γat of the automatic transmission 28, and the chargeable power Win [W] and dischargeable power Wout [W] of the main battery 60, and outputs an engine control signal Se that controls the operation of the engine 12 and an electric motor control signal Smg that controls the operation of the electric motor MG so that the drive torque Tr [N·m] transmitted to the pair of drive wheels 14 achieves the required drive torque Trdem, taking into account transmission loss, the auxiliary load, the gear ratio γat of the automatic transmission 28, the chargeable power Win [W] and dischargeable power Wout [W] of the main battery 60, etc.

[0028] The transmission control unit 104 determines whether to shift the automatic transmission 28 using, for example, a shift map, and outputs a shift control signal Sat to the hydraulic control circuit 54 to execute shift control as necessary. The shift map is a predetermined relationship having shift lines for determining whether to shift the automatic transmission 28 on a two-dimensional coordinate system using, for example, vehicle speed V and required drive torque Trdem as variables. The clutch control unit 106 controls the engagement and disengagement of the clutch K0 via the hydraulic control circuit 54 in accordance with the selected driving mode. The torque converter control unit 108 controls the engagement and disengagement of the lock-up clutch LU of the torque converter 24 via the hydraulic control circuit 54 in accordance with the vehicle state. The relay control unit 110 controls the open / close state of the relay 62. The converter control unit 112 controls the operation state of the DC / DC converter 68 to switch between an operating state and a stopped state.

[0029] From here, we will explain the control functions of the electronic control unit 100 when, based on a predetermined vehicle state, the relay 62 is disconnected, the electric motor MG is put into a non-driving state, and evacuation driving is performed in engine driving mode using the engine 12.

[0030] The abnormality determination unit 114 determines whether the vehicle 10 is in a predetermined vehicle state. The "predetermined vehicle state" is a predetermined vehicle state in which the relay 62 must be disconnected and the electric motor MG must be put into a non-driving state. For example, the predetermined vehicle state includes a case in which the battery temperature THbat, the battery charge / discharge current Ibat, and the battery voltage Vbat are each at a predetermined abnormal value. The relay 62 corresponds to the "relay" in this invention.

[0031] When the abnormality determination unit 114 determines that the vehicle 10 is in a predetermined vehicle state, the electronic control unit 100 controls the electric motor MG to be in a non-driving state and to perform evacuation traveling using the engine 12. Specifically, the relay control unit 110 controls the relay 62 to be in an open state, the electric motor control unit 102b controls the electric motor MG to be in a non-driving state via the inverter 52, and the converter control unit 112 controls the DC / DC converter 68 to be in a stopped state. In addition, the engine control unit 102a controls the operation of the engine 12 to perform evacuation traveling using the engine 12. The transmission control unit 104 controls the shifting of the automatic transmission 28 via the hydraulic control circuit 54. The shifting control of the automatic transmission 28 during evacuation traveling will be described later.

[0032] During evacuation running using the engine 12, the rotor shaft 22 of the electric motor MG, which is in a non-driven state, is rotated by the engine 12, generating a back electromotive force Vemf [V] in the stator coil. Specifically, a rotating magnetic field is generated by the rotation of the rotor provided with permanent magnets, and a back electromotive force Vemf is generated in the stator coil, which is linked to the magnetic flux of this rotating magnetic field. The back electromotive force Vemf depends on the stator coil temperature T coil, the magnet temperature T magnet (which is the temperature of the permanent magnet), and the temperature of the electromagnetic steel sheet that constitutes the electric motor MG. This is because the stator coil temperature T coil, the magnet temperature T magnet, and the temperature of the electromagnetic steel sheet affect characteristics such as the inductance of the stator coil, the magnetic force of the permanent magnet, and the magnetic permeability of the electromagnetic steel sheet. Here, because each part of the electric motor MG (e.g., the stator and rotor) is cooled by circulating cooling oil O, the thermal resistance between these parts is low, and the temperatures of each part of the electric motor MG are substantially the same. Therefore, since the stator coil temperature THcoil, the magnet temperature THmagnet, and the temperature of the electromagnetic steel sheet are substantially the same, the stator coil temperature THcoil described in this specification represents the temperature of each part of the electric motor MG.

[0033] Fig. 2 is a diagram illustrating the relationship between the stator coil temperature THcoil and the motor rotation speed Nmg, and the back electromotive force Vemf generated in the motor MG during evacuation running. Each solid line shown in Fig. 2 represents the relationship between the stator coil temperature THcoil and the back electromotive force Vemf for each rotation speed of the rotor shaft 22, i.e., for each motor rotation speed Nmg.

[0034] As shown in Fig. 2, the higher the motor rotation speed Nmg, the larger the back electromotive force Vemf. For example, as shown in Fig. 2, the lower the stator coil temperature THcoil, the larger the back electromotive force Vemf. The electronic control device 100 stores a map, which is determined in advance experimentally or by design, showing the relationship between the stator coil temperature THcoil and the motor rotation speed Nmg and the back electromotive force Vemf generated by the motor MG, as shown in Fig. 2, for example.

[0035] Returning to FIG. 1, during evacuation running using the engine 12, electric power generated by the electric motor MG is supplied to the air conditioner AC via the inverter 52 and the power line 64. That is, the back electromotive force Vemf generated by the electric motor MG is applied to the air conditioner AC. During evacuation running using the engine 12, the upper limit calculation unit 116 calculates the upper limit Nmg_up of the electric motor rotation speed Nmg based on the stator coil temperature THcoil and the withstand voltage Vws [V] of the air conditioner AC. The "upper limit Nmg_up" is the upper limit of the electric motor rotation speed Nmg at which the back electromotive force Vemf does not exceed the withstand voltage Vws of the air conditioner AC. Note that during evacuation running using the engine 12, the electric motor rotation speed Nmg is equal to the engine rotation speed Ne. Specifically, the upper limit calculation unit 116 calculates the upper limit Nmg_up of the motor rotation speed Nmg at which the back electromotive force Vemf does not exceed the withstand voltage Vws of the air conditioner AC by applying the actual stator coil temperature THcoil to the map described above. The stator coil temperature THcoil corresponds to the "temperature of the stator coil" in this invention. The motor rotation speed Nmg corresponds to the "rotational speed of the motor" in this invention, and the air conditioner AC corresponds to the "device" in this invention.

[0036] Once the upper limit value calculation unit 116 calculates the upper limit value Nmg_up, the shift point setting unit 118 sets upshift points and downshift points based on the accelerator pedal position θacc and the vehicle speed V so that the electric motor rotation speed Nmg does not exceed the upper limit value Nmg_up. An "upshift point" is an operating point for determining an upshift of the automatic transmission 28, and a "downshift point" is an operating point for determining a downshift of the automatic transmission 28. The "upshift point" and the "downshift point" are expressed as shift lines for determining a shift of the automatic transmission 28 on a two-dimensional coordinate system using the accelerator pedal position θacc and the vehicle speed V as variables in a shift map, for example. Preferably, hysteresis is provided between the upshift point and the downshift point. This hysteresis prevents upshifts and downshifts from occurring relatively frequently within a short period of time.

[0037] In this way, the upshift points and downshift points are set according to the upper limit value Nmg_up calculated based on the stator coil temperature THcoil and the withstand voltage Vws of the air conditioner AC. If the upshift points and downshift points are set without reference to the stator coil temperature THcoil, it is necessary to ensure the withstand voltage Vws of the air conditioner AC over the entire practical temperature range of the stator coil temperature THcoil. On the other hand, if the upshift points and downshift points are set based on the stator coil temperature THcoil, it is sufficient to ensure the withstand voltage Vws of the air conditioner AC only at the actual stator coil temperature THcoil. Therefore, if the upshift points and downshift points are set without reference to the stator coil temperature THcoil, the upshift points and downshift points are set at lower rotation speeds than in other cases.

[0038] Preferably, the upshift point and the downshift point are set based on the accelerator opening θacc and the vehicle speed V, as well as on a predetermined difference ΔNmg (=Nmg_up−Nmg) of the electric motor rotation speed Nmg from the upper limit value Nmg_up. The predetermined difference ΔNmg is a value determined in advance through experimentation or design so that the electric motor rotation speed Nmg does not exceed the upper limit value Nmg_up with a margin of error. For example, the predetermined difference ΔNmg is determined so that the electric motor rotation speed Nmg does not exceed the upper limit value Nmg_up even if there is a delay period from when it is determined that the electric motor rotation speed Nmg has reached the upshift point until the electric motor rotation speed Nmg decreases due to the execution of an upshift.

[0039] Once the upshift points and downshift points are set by the shift point setting unit 118, the transmission control unit 104 determines whether to shift the automatic transmission 28 using the upshift points and downshift points set by the shift point setting unit 118, and executes shift control as necessary. If the upshift points and downshift points during evacuation travel are set on the high rotation speed side, the gear ratio γat of the automatic transmission 28 is more likely to be maintained high, and the drive torque Tr transmitted to the pair of drive wheels 14 is more likely to achieve the required drive torque Trdem. In other words, a decrease in power performance during evacuation travel using the engine 12 is suppressed.

[0040] Fig. 3 is an example of a flowchart illustrating the control operation of the electronic control unit 100 shown in Fig. 1. The flowchart of Fig. 3 is repeatedly executed during evacuation running using the engine 12.

[0041] First, in step (hereinafter, step will be omitted) S10, an upper limit value Nmg_up of the electric motor rotation speed Nmg is calculated based on the stator coil temperature THcoil and the withstand voltage Vws of the air conditioner AC. After S10 is executed, in S20, an upshift point and a downshift point are set based on the accelerator opening θacc and the vehicle speed V so that the electric motor rotation speed Nmg does not exceed the upper limit value Nmg_up. After S20 is executed, in S30, gear change control for upshifting and downshifting is executed as needed based on the upshift point and the downshift point. After S30 is executed, the process returns.

[0042] According to this embodiment, (a) based on a predetermined vehicle state, the relay 62 is disconnected, the electric motor MG is put into a non-driven state, and evacuation travel is performed using the engine 12; (b) during evacuation travel, the upper limit value Nmg_up of the electric motor rotation speed Nmg is calculated based on the stator coil temperature THcoil and the withstand voltage Vws of the air conditioner AC; and (c) during evacuation travel, the upshift points and downshift points of the automatic transmission 28 are set so that the electric motor rotation speed Nmg does not exceed the upper limit value Nmg_up. In this manner, the upper limit value Nmg_up of the electric motor rotation speed Nmg and the upshift points and downshift points are set based on the stator coil temperature THcoil and the withstand voltage Vws of the air conditioner AC. Therefore, compared to when the upshift points and downshift points are set not based on the stator coil temperature THcoil, the withstand voltage Vws of the air conditioner AC to which power generated by the electric motor MG is supplied is ensured, and the upshift points and downshift points can be set to higher rotation speeds. This ensures a withstand voltage Vws of the air conditioner AC to which the electric power generated by the electric motor MG is supplied, and also suppresses a decrease in power performance during evacuation running using the engine 12.

[0043] According to this embodiment, the upshift points and downshift points are set based on the accelerator opening θacc, the vehicle speed V, and a predetermined difference ΔNmg between the upper limit value Nmg_up and the electric motor rotation speed Nmg. Since the upshift points and downshift points are set based on the predetermined difference ΔNmg, the electric motor rotation speed Nmg at the upshift points and downshift points is set lower than the upper limit value Nmg_up by the predetermined difference ΔNmg. This ensures a sufficient withstand voltage Vws of the air conditioner AC to which electric power generated by the electric motor MG is supplied, compared to when the upshift points and downshift points are set not based on the predetermined difference ΔNmg.

[0044] The above-described embodiments of the present invention are merely illustrative, and the present invention can be embodied in various forms with various modifications and improvements based on the knowledge of those skilled in the art without departing from the spirit of the present invention.

[0045] In the above-described embodiment, the "device" in the present invention is exemplified as an air conditioner AC, but this is not limiting. For example, the inverter 52 is also included in the device to which the power generated by the motor MG is supplied. In short, all devices to which the power generated by the motor MG, specifically the back electromotive force Vemf, is applied correspond to the "device" in the present invention.

[0046] In the above-described embodiment, the upshift points and downshift points are set based on the stator coil temperature THcoil, but this is not limiting. For example, only the upshift points may be set based on the stator coil temperature THcoil. Even if the upshift points are set based on the stator coil temperature THcoil and the downshift points are set without being based on the stator coil temperature THcoil as in the conventional case, the same effects as those of the first embodiment can be achieved.

[0047] In the above-described embodiment, the vehicle configuration is a two-wheel drive vehicle, but the present invention is not limited to this. For example, in the vehicle configuration described in the above-described embodiment, the present invention can also be applied to a four-wheel drive vehicle in which the output of the automatic transmission 28 is transmitted to all four wheels of the vehicle via a transfer case. [Explanation of symbols]

[0048] 10: vehicle, 12: engine, 14: pair of drive wheels, 28: automatic transmission, 60: main battery (battery), 62: system main relay (relay), 100: electronic control unit (control unit), AC: air conditioner (equipment), MG: electric motor, Nmg: electric motor rotation speed (electric motor rotation speed), Nmg_up: upper limit value, THcoil: stator coil temperature (stator coil temperature), V: vehicle speed, Vws: withstand voltage, ΔNmg: specified difference, θacc: accelerator opening

Claims

1. A control device for a vehicle including an engine as a power source for driving, an automatic transmission provided in a power transmission path between the engine and a pair of drive wheels, an electric motor formed by a permanent magnet type motor generator and rotated in a non-driving state while the vehicle is running using the engine, a battery that supplies and receives electric power to and from the electric motor, and a relay that connects and disconnects the electric motor and the battery, based on a predetermined vehicle state, disconnecting the relay, putting the electric motor into a non-driving state, and executing evacuation running using the engine; During the evacuation traveling, an upper limit value of the rotation speed of the electric motor is calculated based on a temperature of a stator coil of the electric motor and a withstand voltage of a device to which electric power generated by the electric motor is supplied; During the evacuation travel, an upshift point of the automatic transmission is set so that the rotation speed of the electric motor does not exceed the upper limit value. A vehicle control device characterized by:

2. The upshift point is set based on the accelerator opening, the vehicle speed, and a predetermined difference in the rotation speed of the electric motor from the upper limit value.

2. The vehicle control device according to claim 1.

3. During the evacuation travel, a downshift point of the automatic transmission is set so that the rotation speed of the electric motor does not exceed the upper limit value.

3. The vehicle control device according to claim 1 or 2.

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