Vehicle control device

Abstract

To provide a vehicular control device that can suppress decrease in output torque by a driving motor involved in completion of temporary power-up.SOLUTION: Output (generated electric power) of a power generation motor at the time of completing temporary power-up is predicted during the temporary power-up. A limit value of the output of the driving motor during the temporary power-up is set so that output (MG2 consumption power) of the driving motor at the time of completing the temporary power-up is not more than an additional value of the predicted value of the output of the power generation motor and electric power (output of a battery for MG2) determined by subtracting output other than output to the driving motor from rated power of a battery 11. During the temporary power-up, when the MG2 consumption power reaches the limit value, the MG2 consumption power is limited to the limit value until a limited time set in accordance with the limit value and an increase rate of the MG2 consumption power elapses thereafter.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a vehicle control device. [Background technology]

[0002] For example, a series-type hybrid vehicle (HV) is equipped with a power generating motor that generates electricity using engine power, and a drive motor that generates power for running. The hybrid vehicle is also equipped with a battery that stores the electricity used by the power generating motor and the drive motor.

[0003] A hybrid vehicle can run as an HV by having a generator motor generate electricity using engine power and driving a drive motor with the combined power of the generator motor's output and the battery's output. Also, when the engine is stopped, a hybrid vehicle can run as an electric vehicle (EV) by driving the drive motor with the battery's output without generating electricity using the generator motor.

[0004] When a request to accelerate the hybrid vehicle occurs during EV driving of the hybrid vehicle and the output required of the drive motor (required drive power) exceeds the output of the battery, the engine is started and the driving of the hybrid vehicle switches from EV driving to HV driving. When starting the engine, power is supplied from the battery to the generator motor, and the generator motor is powered, thereby cranking the engine with the power of the generator motor.

[0005] Batteries are set with a rated power, which is the upper limit of the power that can be continuously output. In hybrid vehicles equipped with small-sized batteries, when acceleration is requested during EV driving, it is difficult for the rated power of the battery to cover both the power required for cranking the engine and the output of the drive motor to realize a response according to the acceleration request (driver's intention), so the battery output may be temporarily increased from the rated power. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2014-101051 A Summary of the Invention [Problem to be solved by the invention]

[0007] FIG. 3 is a graph showing an example of changes over time in the available power of the drive motor, the power used by the drive motor, the power that can be output from the battery for the drive motor, and the output torque of the drive motor.

[0008] During the temporary boost, the power that can be output from the battery for use by the drive motor is the power (battery output for MG2) obtained by subtracting the output to the drive motor from the rated power of the battery, as shown by the solid line (thin line), plus the power boosted by the temporary boost (temporary boost). However, during engine cranking, power is used by the generator motor, so the power available for the drive motor (MG2 available power) is the power obtained by adding the temporary boost to the battery output for MG2, as shown by the thick line, minus the power used by the generator motor. After engine cranking is completed, that is, after the engine is started, the use of power by the generator motor stops and power generation by the generator motor begins, so the power available for MG2 is the power obtained by adding the temporary boost to the battery output for MG2 and the output of the generator motor (generated power).

[0009] On the other hand, the power usage of the drive motor (power usage of MG2) increases monotonically as the drive motor starts up, as shown by the dashed line. When the power usage of the drive motor reaches the available power of the drive motor, the power usage of the drive motor is limited by the available power of the drive motor, as shown by the overlap of the thick and dashed lines. If the power usage of the drive motor is limited by the available power of the drive motor before the end of the temporary up-time, the available power of the drive motor will decrease by the amount of the temporary up-time as the temporary up-time ends, and the power usage of the drive motor will decrease. When the power usage of the drive motor decreases, the output torque of the drive motor decreases and drivability deteriorates.

[0010] An object of the present invention is to provide a vehicle control device that can suppress a decrease in output torque of a drive motor that occurs when a temporary speed up ends. [Means for solving the problem]

[0011] In order to achieve the above-mentioned object, the vehicle control device of the present invention is a control device for use in a vehicle that is equipped with a battery, an engine, a generator motor that generates electricity using engine power, and a drive motor that generates power for driving by using the output of the battery and, as necessary, the output of the generator motor, and is capable of performing a temporary power-up that temporarily raises the upper limit of the battery output from the rated power, and includes a prediction means for calculating a predicted value of the output of the generator motor at the end of the temporary power-up when power generation by the generator motor is performed in parallel with the temporary power-up, and a limiting means for limiting the output of the drive motor based on the predicted value calculated by the prediction means.

[0012] According to this configuration, a temporary boost is performed in the vehicle to temporarily raise the upper limit of the battery output from the rated power.

[0013] For example, when the vehicle is running in EV mode driven by the drive motor with the engine stopped, if an acceleration request is made by operating the accelerator, the engine is started, the vehicle's running mode switches from EV running to HV running, and the generator motor generates electricity using the engine's power while the drive motor is driven by the combined power of the generator motor's output and the battery's output. When cranking to start the engine, the generator motor uses the battery's output, so the battery's output may temporarily be insufficient, in which case a temporary boost is performed.

[0014] In addition, in a vehicle equipped with an automatic air conditioner, when the ignition switch is turned on while the interior of the vehicle is hot, the cooling capacity is set to maximum and a cool-down process is performed to rapidly cool the interior of the vehicle. During the cool-down process, if an acceleration request is made by operating the accelerator after the vehicle starts to run as a hybrid vehicle, the battery output may be temporarily insufficient because a large amount of the battery output has been taken up by the automatic air conditioner. In this case, a temporary increase in battery output may be performed.

[0015] In these cases, the temporary boost and the power generation by the generator motor are performed in parallel. When the temporary boost ends, the available power for the drive motor is the sum of the power obtained by subtracting the output to the drive motor from the rated power of the battery and the output (generated power) of the generator motor, and if the output of the drive motor exceeds the available power of the drive motor at that point, the output of the drive motor is reduced to the available power of the drive motor. Note that the power used by the drive motor is the same as the output of the drive motor if losses in the drive motor are ignored.

[0016] Therefore, during the temporary speed-up, a predicted value of the output of the generator motor at the end of the temporary speed-up is calculated, and the output of the drive motor is limited based on the predicted value. This makes it possible to suppress a decrease in the power consumption of the drive motor at the end of the temporary speed-up, and to suppress a decrease in the output torque of the drive motor due to the decrease in the power consumption. As a result, a decrease in the acceleration of the vehicle unintended by the driver can be suppressed, and drivability can be improved.

[0017] The limiting means may limit the output of the drive motor so that the output of the drive motor at the end of the temporary up-time is equal to or less than the sum of the predicted value obtained by the prediction means and the output that the drive motor can use within the rated power of the battery.

[0018] With this configuration, when the temporary speed up ends, the output of the drive motor is equal to or less than the available power of the drive motor, and it is possible to prevent a decrease in output torque due to a decrease in the power used by the drive motor. As a result, it is possible to prevent a decrease in the acceleration of the vehicle unintended by the driver, and further improve drivability. Effect of the Invention

[0019] According to the present invention, it is possible to suppress a decrease in the power consumption of the drive motor when the temporary speed up ends, and to suppress a decrease in the output torque of the drive motor due to the decrease in the power consumption, thereby suppressing a decrease in the acceleration of the vehicle unintended by the driver, and improving drivability. [Brief description of the drawings]

[0020] [Figure 1] 1 is a block diagram showing a configuration of a main part of a hybrid vehicle; [Diagram 2] 5 is a graph showing an example of changes over time in available power for a drive motor, power used by the drive motor, and power that can be output from a battery for the drive motor. [Diagram 3] 5 is a graph showing a conventional example of changes over time in available power for a drive motor, power used by the drive motor, power that can be output from a battery for the drive motor, and output torque of the drive motor. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0022] <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.

[0023] 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.

[0024] 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.

[0025] The generator motor 3 and the drive motor 4 are, for example, permanent magnet synchronous motors (PMSMs).

[0026] 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 or the like.

[0027] The drive motor 4 serves as a drive motor that generates power for driving the hybrid vehicle 1, and its rotating shaft is connected to a driving system of the hybrid vehicle 1. The driving system includes, for example, a differential gear, and the power of the drive motor 4 is transmitted to the differential gear and distributed and transmitted from the differential gear to the left and right driving wheels.

[0028] In addition, the hybrid vehicle 1 is equipped with a battery (BAT) 11 and a PCU (Power Control Unit) 12.

[0029] Battery 11 is an assembled battery made up of a combination of multiple secondary batteries. The secondary batteries are, for example, lithium ion batteries. Battery 11 outputs, for example, DC power of approximately 200 to 150 V (volts).

[0030] 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.

[0031] 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.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] In the hybrid vehicle 1, when starting the engine 2, power is supplied from the battery 11 to the generator motor 3, and the generator motor 3 is powered, thereby motoring (cranking) the engine 2 by the generator motor 3. When the rotation speed of the engine 2 has increased to a rotation speed required for firing due to motoring, the ignition plug of the engine 2 is sparked, and the engine 2 fires.

[0037] When the hybrid vehicle 1 is running, the drive motor 4 is powered and generates power. With the engine 2 stopped and the generator motor 3 not generating power, the drive motor 4 is driven by the output of the battery 11, causing the hybrid vehicle 1 to run as an EV as an electric vehicle. Also, with the engine 2 in operation (firing) and the generator motor 3 running in a generating operation (regenerative operation), the drive motor 4 is driven by the combined power of the output (generated power) of the generator motor 3 and the output of the battery 11, causing the hybrid vehicle 1 to run as an HV.

[0038] 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 this resistance acts as a braking force (regenerative braking force) that brakes the hybrid vehicle 1. At this time, the generated power of the drive motor 4 is also supplied to the battery 11, thereby charging the battery 11.

[0039] <Drive restriction processing> FIG. 2 is a graph showing an example of changes over time in the available power of the drive motor 4, the power used by the drive motor 4, and the power that can be output from the battery 11 for the drive motor 4. In FIG.

[0040] For example, when the hybrid vehicle 1 is running in EV mode and a request for acceleration is made by the driver stepping on the accelerator pedal, the engine 2 is started, the running of the hybrid vehicle 1 is switched from EV running to HV running, and the driving motor 4 is driven by the combined power of the output of the generator motor 3 and the output of the battery 11 while the generator motor 3 generates electricity with the power of the engine 2. Since the output of the battery 11 is used by the generator motor 3 during cranking to start the engine 2, the output of the battery 11 may temporarily be insufficient. In such a case, the HVECU 17 temporarily increases the upper limit of the output of the battery 11 from the rated power. The rated power is the power that can be output continuously from the battery 11 for a long period of time, and is set to a value at which abnormalities such as thermal destruction do not occur even if that power is output continuously for a long period of time.

[0041] During the temporary boost, the power that can be output from the battery 11 to the drive motor 4 is the power obtained by subtracting the output to the motors other than the drive motor from the rated power of the battery 11 (hereinafter referred to as the "battery output for MG2") plus the boost due to the temporary boost (temporary boost), as shown by the solid line (thin line). However, during cranking of the engine 2, power is used by the generator motor 3, so the power available for the drive motor 4 (hereinafter referred to as the "power available for MG2") is the power obtained by subtracting the power used by the generator motor 3 from the power obtained by adding the temporary boost to the battery output for MG2, as shown by the thick line. After cranking of the engine 2 ends, the use of power by the generator motor 3 stops and power generation by the generator motor 3 begins, so the power available for MG2 is the sum of the battery output for MG2, the temporary boost, and the output of the generator motor 3.

[0042] When the temporary power-up ends, the power available for MG2 decreases from the sum of the MG2 battery output, the temporary power-up, and the output of the generator motor 3 to the sum of the MG2 battery output and the output of the generator motor 3. If the power used by the drive motor 4 (hereinafter referred to as "power used by MG2") exceeds the power available for MG2 at the end of the temporary power-up, the power used by MG2 is limited to the power available for MG2, and the output of the drive motor 4 is reduced to the power available for MG2.

[0043] Therefore, during the temporary up-shift, the HVECU 17 predicts the output (generated power) of the generator motor 3 at the end of the temporary up-shift. The rate at which the output of the generator motor 3 increases varies depending on the rate at which the rotation speed of the engine 2 increases, and the rate at which the rotation speed of the engine 2 increases varies depending on the vehicle speed of the hybrid vehicle 1, the accelerator opening (the ratio of the current operation amount to the maximum operation amount of the accelerator pedal), the setting of the drive mode (motion characteristics) of the hybrid vehicle 1, and the like. Therefore, for example, a relationship between the vehicle speed and accelerator opening and a predicted value of the output of the generator motor 3 at the end of the temporary up-shift is determined for each of a plurality of drive modes (normal mode, sports mode, etc.) and stored in the non-volatile memory of the HVECU 17, and during the temporary up-shift, the HVECU 17 acquires the settings of the vehicle speed, accelerator opening, and drive mode, and obtains a predicted value of the output of the generator motor 3 according to the setting of the vehicle speed, accelerator opening, and drive mode from the relationships stored in the non-volatile memory.

[0044] Then, the HVECU 17 sets a limit value for the output of the drive motor 4 during the temporary power-up so that the output of the drive motor 4 at the end of the temporary power-up will be equal to or less than the sum of the predicted output of the generator motor 3 and the MG2 battery output. The output of the drive motor 4 is the same as the power used by MG2, if losses in the drive motor 4 are ignored. When the power used by MG2 reaches the limit value during the temporary power-up, the power used by MG2 is limited to the limit value from that point on until the elapse of a limit time that is set according to the limit value and the rate of increase of the power used by MG2.

[0045] <Effects> As a result, at the end of the temporary up-time, the output of the drive motor 4 can be made equal to or less than the sum of the predicted output of the generator motor 3 and the battery output for MG2, that is, equal to or less than the power available for MG2. This makes it possible to prevent a decrease in the output of the drive motor 4 at the end of the temporary up-time. As a result, it is possible to prevent a decrease in the output torque of the drive motor 4 at the end of the temporary up-time, and it is possible to prevent a decrease in the acceleration of the hybrid vehicle 1 due to the decrease in output torque, thereby improving drivability.

[0046] <Modification> Although one embodiment of the present invention has been described above, the present invention can be embodied in other forms.

[0047] For example, in the above-described embodiment, a predicted value of the output of the generator motor 3 according to the settings of the vehicle speed, accelerator opening and drive mode is obtained from the relationship stored in the non-volatile memory, but the predicted value of the output of the generator motor 3 at the end of the temporary up-time may be a fixed value independent of the settings of the vehicle speed, accelerator opening and drive mode, or may be a variable value depending on one or two of the settings of the vehicle speed, accelerator opening and drive mode.

[0048] When the predicted value of the output of the generator motor 3 is a fixed value, the fixed value is set, for example, to the minimum value that ensures that the generator motor 3 is outputting at the end of the temporary uptime.

[0049] In addition, if the predicted value of the output of the generator motor 3 is a variable value, the actual value of the output of the generator motor 3 at the end of the temporary up-time may be obtained, and the relationship between the vehicle speed, accelerator opening and / or drive mode settings and the predicted value may be updated by learning using that actual value.

[0050] In the above embodiment, the hybrid vehicle 1 equipped with a series type hybrid system has been described, but the present invention is applicable 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.

[0051] In addition, various design modifications can be made to the above-described configuration within the scope of the claims. [Explanation of symbols]

[0052] 1: Hybrid vehicle (vehicle) 2: Engine 3: Generator motor 4: Drive motor 11:Battery 17: HVECU (controller, predictor, limiter)

Claims

1. A control device for a vehicle equipped with a battery, an engine, a generator motor that generates power using power from the engine, and a drive motor that generates power for traveling by using the output of the battery and, as necessary, the output of the generator motor, and capable of temporarily raising an upper limit of the output of the battery from a rated power, comprising: a prediction means for calculating a predicted value of an output of the generator motor at a time when the generator motor is generating electricity in parallel with the temporary up-time; a limiting means for setting a limiting value based on the predicted value obtained by the predicting means, and, when the output of the drive motor reaches the limiting value, limiting the output of the drive motor to the limiting value from the point at which the output of the drive motor reaches the limiting value until a limit time set according to a rate of increase of the output of the drive motor has elapsed.

2. 2. The vehicle control device according to claim 1, wherein the limiting means limits the output of the drive motor at the end of the temporary uptime to an output equal to or less than the sum of the predicted value obtained by the prediction means and the output that the drive motor can use within the rated power of the battery.

3. The vehicle is provided with a plurality of drive modes for setting motion characteristics of the vehicle, The vehicle control device according to claim 1 , wherein the prediction means determines the predicted value according to a setting of the drive mode.

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