Vehicle control device

Abstract

To provide a vehicular control device which can suppress fluctuation of motor output even if a motor temperature is hunting in the situation that the motor output is limited by a limit value according to the motor temperature without enlarging a range in which the motor output is limited.SOLUTION: In a limit range in which MG temperature is higher than a limit start threshold T1, a limit value of MG output is so set as to broadly-defined monotonously decrease as the MG temperature increases, and the MG output is limited with the limit value as an upper limit. In concrete, even if the MG temperature increases in a range in which an upper limit and a lower limit of the limit range is included in the limit range, a range T1 to T2, T2 to T3, T3 to T4, T4 to T5, in which the limit value becomes constant, is provided. In this range, even if the MG temperature is hunching in the situation that the MG output is limited by the limit value, the MG output is kept constant.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a control device for use in a vehicle equipped with a motor that generates power for running the vehicle. [Background technology]

[0002] For example, a hybrid vehicle is equipped with a motor that generates power for driving, and this motor is a permanent magnet synchronous motor. A permanent magnet synchronous motor generates heat due to copper loss and iron loss during operation, and if it becomes too hot, it may demagnetize or the resin mold that covers the coil may be thermally destroyed. Therefore, in a hybrid vehicle, the motor output (MG output) is limited according to the motor temperature (MG temperature), and the temperature rise of the motor is suppressed. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2014-101051 A Summary of the Invention [Problem to be solved by the invention]

[0004] FIG. 3 is a graph showing a conventional example of the relationship between the MG temperature and the limit value of the MG output.

[0005] In a hybrid vehicle, a component protection criterion that must not be exceeded in order to protect each component of the motor is set for the MG temperature, and an output stop threshold lower than the component protection criterion and a restriction start threshold even lower than the output stop threshold are set. Then, a limit value of the MG output is set in a range in which the MG temperature is higher than the restriction start threshold. That is, in a range in which the MG temperature is higher than the restriction start threshold and lower than the output stop threshold, the limit value of the MG output is set to become monotonically smaller as the MG temperature increases, and in a range in which the MG temperature is equal to or higher than the output stop threshold, the limit value of the MG output is set to 0.

[0006] Therefore, if the MG temperature hunts in a range higher than the restriction start threshold, the limit value of the MG output also hunts, and in a situation where the MG output is limited to the limit value, the MG output fluctuates and drivability deteriorates. For example, by filtering the MG temperature, the fluctuation of the MG output can be suppressed and the deterioration of drivability can be prevented. However, since a delay occurs in the detection of the MG temperature due to the filtering process, the restriction start threshold must be set taking this delay into account, and the range in which the MG output is limited expands (the restriction start threshold becomes lower).

[0007] The object of the present invention is to provide a vehicle control device that can suppress fluctuations in motor output even if the motor temperature hunts in a situation where the motor output is limited to a limit value corresponding to the motor temperature, without expanding the range in which the motor output is limited. [Means for solving the problem]

[0008] In order to achieve the above-mentioned object, the vehicle control device of the present invention is a control device used in a vehicle equipped with a motor that generates power for driving, and includes an output control means for controlling the motor output of the motor, and a limit value setting means for setting a limit value of the motor output corresponding to the motor temperature when the motor temperature of the motor is higher than the limit start threshold, and when a limit value is set by the limit value setting means, the output control means controls the motor output using the limit value as an upper limit of the motor output, and the limit value setting means sets the limit value corresponding to the motor temperature so that, in a limit range where the motor temperature is higher than the limit start threshold, the limit value monotonically decreases in a broad sense as the motor temperature increases, and a range in which the limit value remains constant even when the motor temperature rises is included within the limit range that does not include the upper and lower limits of the limit range.

[0009] According to this configuration, in the limited range where the motor temperature is higher than the limit start threshold, the limit value of the motor output is set to monotonically decrease broadly as the motor temperature increases, and the motor output is controlled with the limit value as the upper limit. As a result, the limit on the motor output becomes stronger as the motor temperature increases, so that the increase in the motor temperature can be suppressed.

[0010] In addition, a range that does not include the upper and lower limits of the limit range is provided in which the limit value remains constant even if the motor temperature rises. In this range, even if the motor temperature hunts while the motor output is limited by the limit value, the motor output remains constant, so fluctuations in the motor output can be suppressed. Moreover, since the motor temperature is not filtered, there is no need to set the limit start threshold low in consideration of the delay caused by the filtering process, and the range in which the motor output is limited is not expanded.

[0011] The limit value setting means may set the limit value corresponding to the upper limit of the limit range of the motor temperature to a predetermined value greater than 0, and set the limit value corresponding to a motor temperature higher than the upper limit of the limit range to 0.

[0012] In this configuration, when the motor temperature exceeds the upper limit of the limit range, the limit value is suddenly reduced from a predetermined value to 0. Therefore, a larger margin can be secured between the lower limit of the motor temperature (output stop threshold) where the limit value is set to 0 and the component protection criteria, compared to a configuration in which the limit value is gradually reduced from a predetermined value to 0 as the motor temperature rises from the upper limit of the limit range. As a result, it is possible to effectively prevent the motor temperature from reaching the component protection criteria.

[0013] The limit value setting means may set a limit value according to the motor temperature so that the motor output decreases stepwise with an increase in the motor temperature within the limited range.

[0014] In this configuration, when the motor output is limited by a limit value, the motor output is reduced stepwise as the motor temperature rises, and this is reflected in the vehicle behavior, so that the user can intuitively recognize that the motor output is being limited because the motor temperature is high. Also, compared to a configuration in which the motor output is continuously reduced, the content of the motor output control (control of the inverter that drives the motor) can be simplified. Effect of the Invention

[0015] According to the present invention, in a situation where the motor output is limited to a limit value corresponding to the motor temperature, fluctuations in motor output can be suppressed even if the motor temperature hunts, without expanding the range in which the motor output is limited. [Brief description of the drawings]

[0016] [Figure 1] 1 is a block diagram showing a configuration of a main part of a hybrid vehicle in which a vehicle control device according to an embodiment of the present invention is adopted; [Diagram 2] 4 is a graph showing an example of a relationship between an MG temperature and a limit value of an MG output. [Diagram 3] 1 is a graph showing a conventional example of the relationship between MG temperature and the limit value of MG output. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0018] <Main components of hybrid vehicles> FIG. 1 is a block diagram showing the configuration of a main part of a hybrid vehicle 1. As shown in FIG.

[0019] The hybrid vehicle 1 is a vehicle equipped with a series hybrid system. The hybrid vehicle 1 is equipped with an engine 2, a generator motor (MG1) 3, and a drive motor (MG2) 4.

[0020] The engine 2 is, for example, a gasoline engine, and is equipped with an electronic throttle valve for adjusting the amount of air intake into the combustion chamber, an injector (fuel injection device) for injecting fuel into the intake air, and an ignition plug for generating an electrical discharge in the combustion chamber.

[0021] The generator motor 3 and the drive motor 4 are, for example, permanent magnet synchronous motors (PMSMs). The permanent magnet synchronous motor includes a stator and a rotor. The stator includes a stator core and a coil. The stator core includes an annular (cylindrical) stator yoke and a plurality of teeth extending radially inward from the stator yoke, and the coils are wound around each tooth in a concentrated manner. The rotor is disposed inside the stator and includes an annular rotor yoke concentric with the stator yoke and a plurality of permanent magnets embedded in the rotor yoke in a line in the circumferential direction. When a current flows through the coil of the stator, a magnetic flux is generated that extends in the rotational radial direction along the teeth, and this magnetic flux acts on the permanent magnet of the rotor, generating a rotational force in the rotor. Therefore, by controlling the current flowing through the coil according to the rotational position of the rotor, a rotational force is continuously generated in the rotor, causing the rotor to rotate.

[0022] The generator motor 3 is a generator motor that generates electricity using the power of the engine 2, and its rotating shaft is mechanically connected to the crankshaft of the engine 2 via gears and the like. The drive motor 4 is a drive motor that generates power for running the hybrid vehicle 1, and its rotating shaft is connected to a running drive system of the hybrid vehicle 1. The running drive system includes, for example, a differential gear, and the power of the drive motor 4 is transmitted to the differential gear, and then distributed and transmitted from the differential gear to the left and right drive wheels.

[0023] In addition, the hybrid vehicle 1 is equipped with a battery (BAT) 11 and a PCU (Power Control Unit) 12.

[0024] The battery 11 is an assembled battery made up of a combination of a plurality of secondary batteries. The secondary batteries are, for example, lithium ion batteries. The battery 11 outputs, for example, DC power of about 200 to 150 V (volts).

[0025] The PCU 12 is a unit for controlling the driving of the generator motor 3 and the drive motor 4, and includes inverters 13 and 14, a converter (CONV) 15, and an MGECU 16.

[0026] The inverter (INV1) 13 is a three-phase voltage type inverter that drives the generator motor 3, and has a configuration in which a series circuit of two IGBTs (Insulated Gate Bipolar Transistors) is provided corresponding to each of the U-phase, V-phase, and W-phase, and these series circuits are connected in parallel between a positive wiring and a negative wiring. When the generator motor 3 is in power running operation, the inverter 13 converts DC power to AC power and supplies the AC power to the generator motor 3. Furthermore, when the generator motor 3 is in regenerative operation (power generation operation), the inverter 13 converts the AC power generated by the generator motor 3 into DC power.

[0027] The inverter (INV2) 14 is a three-phase voltage type inverter that drives the drive motor 4, and similarly to the inverter 13, has a configuration in which two IGBT series circuits are provided corresponding to each of the U, V, and W phases, and these series circuits are connected in parallel to each other between a positive wiring and a negative wiring. When the drive motor 4 is in a power running operation, the inverter 14 converts DC power to AC power and supplies the AC power to the drive motor 4. Furthermore, when the drive motor 4 is in a regenerative operation (power generation operation), the inverter 14 converts the AC power generated by the drive motor 4 into DC power.

[0028] The converter 15 boosts the DC power output from the battery 11 and supplies it to the inverters 13, 14 when the generator motor 3 and the drive motor 4 are in power running mode. In addition, the converter 15 lowers the DC power output from the inverters 13, 14 and supplies it to the battery 11 when the generator motor 3 and the drive motor 4 are in regenerative running mode.

[0029] The hybrid vehicle 1 is equipped with a plurality of ECUs (Electronic Control Units), and the MGECU 16 is one of the plurality of ECUs. Each ECU is equipped with a microcontroller, and the microcontroller includes, for example, a CPU, a non-volatile memory such as a flash memory, and a volatile memory such as a dynamic random access memory (DRAM). The plurality of ECUs are connected to each other so as to enable two-way communication according to a CAN (Controller Area Network) communication protocol.

[0030] The multiple ECUs include an HVECU 17. The HVECU 17 controls the engine 2, and also controls the generator motor 3 and the drive motor 4 via the PCU 12. In controlling the generator motor 3 and the drive motor 4, a torque command value for the generator motor 3 and a torque command value for the drive motor 4 are input from the HVECU 17 to the MGECU 16. The MGECU 16 controls the operations of the inverters 13, 14 and the converter 15 based on the torque command value input from the HVECU 17.

[0031] In the hybrid vehicle 1, when starting the engine 2, the DC power output from the battery 11 is boosted by the converter 15, the boosted DC power is converted to AC power by the inverter 13, and the AC power is supplied to the generator motor 3. This causes the generator motor 3 to perform power running, and the engine 2 is motored (cranked) by the generator motor 3. When the rotation speed of the engine 2 has increased to a rotation speed required for firing by motoring, the engine 2 fires when the spark plug of the engine 2 is sparked.

[0032] When the hybrid vehicle 1 is traveling, the drive motor 4 is operated in a power running mode and generates power.

[0033] When the sum of the outputs required for the generator motor 3 and the drive motor 4 is smaller than the output of the battery 11, the hybrid vehicle 1 runs in EV mode. That is, the engine 2 is stopped, no power is generated by the generator motor 3, and power is supplied from the battery 11 to the drive motor 4, which drives the drive motor 4.

[0034] On the other hand, when the sum of the outputs required for the generator motor 3 and the drive motor 4 exceeds the output of the battery 11, the hybrid vehicle 1 runs as an HV. That is, the engine 2 is put into operation (firing) and the generator motor 3 is operated to generate electricity (regenerative operation), so that the power of the engine 2 is converted into AC power by the generator motor 3. The AC power from the generator motor 3 is then converted into DC power by the inverter 13, and the DC power output from the inverter 13 is converted into AC power by the inverter 14, and the AC power is supplied to the drive motor 4, thereby driving the drive motor 4.

[0035] Furthermore, when the remaining charge of the battery 11 falls below a predetermined level, the generator motor 3 operates to generate electricity while the engine 2 is firing, regardless of whether the drive motor 4 is driven or stopped. At this time, AC power from the generator motor 3 is converted to DC power by the inverter 13, and the DC power output from the inverter 13 is stepped down by the converter 15, and the stepped-down DC power is supplied to the battery 11, thereby charging the battery 11.

[0036] When the hybrid vehicle 1 decelerates, the drive motor 4 is operated in a regenerative manner, and the power transmitted from the drive wheels to the drive motor 4 is converted into AC power. At this time, the drive motor 4 acts as a resistance in the traveling drive system, and the resistance acts as a braking force (regenerative braking force) that brakes the hybrid vehicle 1. At this time, too, the AC power from the drive motor 4 is converted into DC power by the inverter 14, and the DC power output from the inverter 13 is stepped down by the converter 15, and the stepped-down DC power is supplied to the battery 11, thereby charging the battery 11.

[0037] Various sensors required for control are connected to the HVECU 17, and detection signals from the connected sensors are input. The sensors include a thermistor 18. Thermistor 18 is attached to the stator core of the drive motor 4, and outputs a detection signal corresponding to the temperature of the stator core. The HVECU 17 calculates the temperature of the stator core of the drive motor 4 from the detection signal from thermistor 18, and detects the calculated stator core temperature as the temperature of the drive motor 4 (hereinafter referred to as "MG temperature").

[0038] <Output restriction process> FIG. 2 is a graph showing an example of the relationship between the MG temperature and the limit value of the MG output.

[0039] In the hybrid vehicle 1, a component protection criterion that must not be exceeded in order to protect each component of the drive motor 4 is set for the MG temperature, and a restriction start threshold T1 that is lower than the component protection criterion is set. When the MG temperature rises to a temperature higher than the restriction start threshold T1, the output of the drive motor 4 (hereinafter referred to as "MG output") is restricted.

[0040] In order to limit the output of the drive motor 4, the relationship between the MG temperature and the limit value of the MG output is stored in the non-volatile memory of the HVECU 17. The HVECU 17 detects the MG temperature, sets a limit value according to the MG temperature based on the relationship between the MG temperature and the limit value of the MG output, and sets a torque command value for the drive motor 4 so that the MG output is limited to or below the limit value.

[0041] When the MG temperature is in a range equal to or lower than the restriction start threshold T1, the limit value is set to the maximum output value of the drive motor 4, and when the MG temperature is in a range higher than the restriction start threshold T1, the limit value is set to decrease in five stages from the maximum output value of the drive motor 4 to 0. Specifically, when the MG temperature is higher than the restriction start threshold T1 and is in a range equal to or lower than the second restriction threshold T2, the limit value is set to a first limit value R1 lower than the maximum output value of the drive motor 4. When the MG temperature is higher than the second limit threshold T2 and is in a range equal to or lower than the third limit threshold T3 (>T2), the limit value is set to a second limit value R2 lower than the first limit value R1. When the MG temperature is higher than the third limit threshold T3 and is in a range equal to or lower than the fourth limit threshold T4 (>T3), the limit value is set to a third limit value R3 lower than the second limit value R2. When the MG temperature is higher than the fourth limit threshold T4 and is in a range equal to or lower than the fifth limit threshold T5 (>T4), the limit value is set to a fourth limit value R4 lower than the third limit value R3. In the range where the MG temperature is higher than the fifth limit threshold T5, the limit value is set to zero.

[0042] The state in which the limit value is set to the maximum output value of the drive motor 4 is equivalent to a state in which no limit value is set. The state in which the limit value is set to 0 is equivalent to a state in which the output of the drive motor 4 is stopped, and the fifth limit threshold T5 is an output stop threshold at which the output of the drive motor 4 is stopped.

[0043] The relationship between the MG temperature and the limit value of the MG output is created, for example, by setting a first limit value R1, a second limit value R2, a third limit value R3 and a fourth limit value R4, and by setting a straight line shown by a two-dot dashed line in Figure 2, i.e., a straight line along which the limit value of the MG output decreases proportionally from the maximum output value of the drive motor 4 to 0 as the MG temperature rises from the limit start threshold T1 to a temperature that is a certain amount lower than the component protection criteria, and by setting the MG temperatures on that straight line corresponding to the first limit value R1, the second limit value R2, the third limit value R3 and the fourth limit value R4 as the second limit threshold T2, the third limit threshold T3, the fourth limit threshold T4 and the fifth limit threshold T5, respectively. In addition, a relationship between the MG temperature and the limit value of the MG output may be created by setting the second limit threshold T2, the third limit threshold T3, the fourth limit threshold T4 and the fifth limit threshold T5, and setting a straight line indicated by a two-dot dashed line in FIG. 2, and setting the MG outputs corresponding to the second limit threshold T2, the third limit threshold T3, the fourth limit threshold T4 and the fifth limit threshold T5 on that straight line as the first limit value R1, the second limit value R2, the third limit value R3 and the fourth limit value R4, respectively.

[0044] In any case, the first limit value R1, the second limit value R2, the third limit value R3 and the fourth limit value R4 are set so that the difference between the maximum output value and the first limit value R1, the difference between the first limit value R1 and the second limit value R2, the difference between the second limit value R2 and the third limit value R3, the difference between the third limit value R3 and the fourth limit value R4, and the difference between the fourth limit value R4 and 0 are greatest in that order.

[0045] The non-volatile memory of the HVECU 17 also stores the relationship between the MG temperature and the limit value of the MG output when the limit on the output of the drive motor 4 is released. When the output limit of the drive motor 4 is released, the HVECU 17 detects the MG temperature, sets a limit value according to the MG temperature from the relationship between the MG temperature and the limit value of the MG output, and sets a torque command value for the drive motor 4 so that the MG output is limited to or below the limit value.

[0046] In a state where the limit value according to the MG temperature is set to 0, the limit value is returned from 0 to the fourth limit value R4 in response to the MG temperature decreasing to the fifth release threshold T'5 lower than the fifth limit threshold T5. In a state where the limit value according to the MG temperature is set to the fourth limit value R4, the limit value is returned from the fourth limit value R4 to the third limit value R3 in response to the MG temperature decreasing to the fourth release threshold T'4 lower than the fourth limit threshold T4. In a state where the limit value according to the MG temperature is set to the third limit value R3, the limit value is returned from the third limit value R3 to the second limit value R2 in response to the MG temperature decreasing to the third release threshold T'3 lower than the third limit threshold T3. In a state where the limit value according to the MG temperature is set to the second limit value R2, the limit value is returned from the second limit value R2 to the first limit value R1 in response to the MG temperature decreasing to the second release threshold T'2 lower than the second limit threshold T2. Then, when the limit value according to the MG temperature is set to the first limit value R1, in response to the MG temperature dropping to the first release threshold T'1 which is lower than the restriction start threshold T1, the limit value is returned from the first limit value R1 to the maximum output value, and the output restriction of the drive motor 4 is released.

[0047] <Action and effect> As described above, in the limited range where the MG temperature is higher than the restriction start threshold T1, the limit value of the MG output is set to decrease monotonically in a broad sense as the MG temperature increases, and the MG output is controlled with the limit value as the upper limit. As a result, the restriction on the MG output becomes stronger as the MG temperature increases, making it possible to suppress an increase in the MG temperature.

[0048] Furthermore, within the limit range, but not including the upper and lower limits, there are provided ranges T1-T2, T2-T3, T3-T4, and T4-T5 in which the limit value remains constant even if the MG temperature rises. In these ranges, even if the MG temperature hunts in a situation in which the MG output is limited by the limit value, the MG output remains constant, so fluctuations in the MG output can be suppressed. Moreover, since filtering of the MG temperature is not performed, there is no need to set the limit start threshold T1 low in consideration of the delay due to filtering, and the range in which the MG output is limited is not expanded.

[0049] In the limit range where the MG temperature is higher than the limit start threshold T1, the limit value is set to decrease in five stages from the maximum output value of the drive motor 4 to 0. With this configuration, in a situation where the MG output is limited by the limit value, the MG output decreases stepwise as the MG temperature increases, and this is manifested as the behavior of the vehicle, so that the user can intuitively recognize that the MG output is limited due to the high MG temperature. In addition, compared to a configuration in which the MG output is continuously decreased, the MG output does not need to be changed finely, so the content of the control of the MG output (control of the inverter 14 that drives the drive motor 4) can be simplified. Furthermore, in a situation where the MG output is limited by the limit value, the MG output limited along the thick solid line shown in FIG. 2 is equal to or lower than the MG output limited along the two-dot chain line shown in FIG. 2, so that the increase in the MG temperature can be further suppressed.

[0050] Moreover, when the MG temperature exceeds the fifth limit threshold T5, which is the upper limit of the limit range, the limit value is suddenly reduced from the fourth limit value R4 to 0. Therefore, a larger margin can be secured between the output stop threshold, which is the lower limit of the MG temperature at which the limit value is set to 0, and the component protection criteria, compared to a configuration in which the limit value is gradually reduced from the fifth limit threshold T5 to 0 as the MG temperature rises from the upper limit of the limit range, i.e., a configuration in which the relationship between the MG temperature and the limit value of the MG output is as shown by the two-dot chain line in Fig. 2. As a result, it is possible to effectively prevent the MG temperature from reaching the component protection criteria.

[0051] Furthermore, the first limit value R1, the second limit value R2, the third limit value R3, and the fourth limit value R4 are set so that the difference between the maximum output value and the first limit value R1, the difference between the first limit value R1 and the second limit value R2, the difference between the second limit value R2 and the third limit value R3, the difference between the third limit value R3 and the fourth limit value R4, and the difference between the fourth limit value R4 and 0 are increased in that order, so that the higher the MG temperature is, the larger the change range when the limit value of the MG output is changed. As a result, the higher the MG temperature is, the stronger the suppression of the rise in the MG temperature can be achieved.

[0052] In addition, hysteresis is provided for the thresholds T1, T2, T3, T4, and T5 when the limit value is set to a value one step smaller, and for the thresholds T'1, T'2, T'3, T'4, and T'5 when the limit value is returned from a value one step smaller to a value one step larger, thereby preventing the limit value from switching frequently and suppressing fluctuations in the MG temperature due to switching of the limit value.

[0053] <Modification> Although one embodiment of the present invention has been described above, the present invention can be embodied in other forms.

[0054] For example, in the above embodiment, the limit value of the MG output is reduced from the maximum output value to the first limit value R1 in response to the MG temperature exceeding the limit start threshold T1, but the limit value of the MG output may be gradually reduced from the maximum output value to the first limit value R1 while the MG temperature rises from the limit start threshold T1 to a value that is greater than the limit start threshold T1 and less than the second limit threshold T2. Similarly, the limit value of the MG output may be gradually reduced from the first limit value R1 to the second limit value R2 while the MG temperature rises from the second limit threshold T2 to a value that is greater than the second limit threshold T2 and less than the third limit threshold T3. Also, the limit value of the MG output may be gradually reduced from the second limit value R2 to the third limit value R3 while the MG temperature rises from the third limit threshold T3 to a value that is greater than the third limit threshold T3 and less than the fourth limit threshold T4. The limit value of the MG output may be gradually reduced from the third limit value R3 to the fourth limit value R4 while the MG temperature rises from the fourth limit threshold T4 to a value greater than the fourth limit threshold T4 and less than the fifth limit threshold T5. The limit value of the MG output may be gradually reduced from the fourth limit value R4 to 0 as the MG temperature rises from the fifth limit threshold T5.

[0055] In the above embodiment, the relationship between the MG temperature and the limit value of the MG output is stored in the non-volatile memory of the HVECU 17, and the limit value according to the MG temperature is set based on the relationship. However, the present invention is not limited to this. The relationship between a variable having a positive correlation with the MG temperature and the limit value of the MG output may be stored in the non-volatile memory of the HVECU 17, and the limit value according to the variable having a positive correlation with the MG temperature may be set based on the relationship. Examples of the variable having a positive correlation with the MG temperature include the temperature of a switching element included in the inverter 14 that drives the drive motor 4 and the temperature of the cooling water that cools the PCU 12.

[0056] Furthermore, the non-volatile memory of HVECU17 may store the MG temperature or a variable having a positive correlation with the MG temperature and the MG output limit rate (the ratio of the limit value to the maximum output value of the drive motor 4), and based on this relationship, a limit rate according to the MG temperature, etc. may be set, and the limit value may be set to a value obtained by multiplying the maximum output value of the drive motor 4 by the limit rate.

[0057] In addition, in the above-described embodiment, when the difference between the maximum output value and the first limit value R1 is defined as the first limit amount, the difference between the first limit value R1 and the second limit value R2 is defined as the second limit amount, the difference between the second limit value R2 and the third limit value R3 is defined as the third limit amount, and the difference between the third limit value R3 and the fourth limit value R4 is defined as the fourth limit amount, the first limit amount, the second limit amount, the third limit amount and the fourth limit amount have a relationship of first limit amount<second limit amount<third limit amount<fourth limit amount. However, the first limit amount, the second limit amount, the third limit amount and the fourth limit amount may be set so as to have a relationship of, for example, first limit amount=second limit amount<third limit amount=fourth limit amount. As a result, while the MG temperature exceeds the restriction start threshold T1 by a small amount, the increase in MG temperature can be suppressed while minimizing the decrease in driving performance of the hybrid vehicle 1 due to a decrease in MG output. If the MG temperature continues to rise, the amount of restriction on the MG output is increased, and protection of components such as the drive motor 4 can be prioritized over ensuring driving performance.

[0058] In the above embodiment, the hybrid vehicle 1 equipped with a series type hybrid system has been described, but the present invention can be applied to vehicles equipped with hybrid systems of types other than the series type, such as a series-parallel type. In a series-parallel type hybrid system, for example, an engine and a motor are connected to a planetary gear mechanism, and the power from the engine can be divided and distributed to the motor and the drive wheels, and the power from the engine and the power from the motor can be combined and transmitted to the drive wheels. In addition, the present invention is not limited to vehicles that employ a hybrid system, and can also be applied to electric vehicles (EVs) as long as the vehicle is equipped with a motor.

[0059] In addition, various design modifications can be made to the above-described configuration within the scope of the claims. [Explanation of symbols]

[0060] 1: Hybrid vehicle (vehicle) 4: Drive motor (motor) 17: HVECU (vehicle control device, output control means, limit value setting means) T1-T2, T2-T3, T3-T4, T4-T5: Range

Claims

1. A control device used in a vehicle equipped with a motor that generates power for driving, an output control means for controlling a motor output of the motor; a limit value setting means for setting a limit value of the motor output according to the motor temperature when the motor temperature of the motor is higher than a limit start threshold value, when the limit value is set by the limit value setting means, the output control means controls the motor output with the limit value as an upper limit of the motor output, The limit value setting means sets the limit value corresponding to the motor temperature so that, in a limit range where the motor temperature is higher than the limit start threshold, the limit value decreases in three or more stages as the motor temperature increases, with the decrease in each stage becoming greater, and the limit value remains constant even when the motor temperature increases, within a range that does not include the upper and lower limits of the limit range.

2. 2. The vehicle control device according to claim 1, wherein the limit value setting means sets the limit value corresponding to the motor temperature at the upper limit of the limit range to a predetermined value greater than 0, and sets the limit value corresponding to the motor temperature higher than the upper limit of the limit range to 0.

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