JP2015009746A - Control device for hybrid vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress discomfort felt by a driver when an engine is started and stopped.SOLUTION: When a charging state SOC of a power storage device 20 becomes equal to or less than a charging threshold SOC_CHG in a second travel mode, an engine 12 is started and the mode is shifted to a first travel mode with a condition that vehicle requirement drive force Tp is increased after the charging state becomes equal to or less than the charging threshold. In the first travel mode, when the charging state SOC of the power storage device 20 becomes equal to or more than a discharge threshold SOC_DCHG, the engine 12 is stopped and the mode is shifted to the second travel mode with a condition that the vehicle requirement drive force Tp is decreased after the charging state becomes equal to or more than the discharge threshold.

Description

  The present invention includes a first travel mode in which the vehicle travels and the power storage device is charged using the power of the engine, and a second travel mode in which the vehicle travels using the power of the power storage device while the engine is stopped. The present invention relates to a control device for a hybrid vehicle that can be selected, and particularly relates to control when switching between a first travel mode and a second travel mode.

  In Patent Document 1 below, when it is determined that the state of charge is insufficient, the engine is intermittently operated, the engine is started when the accelerator is on or brake off, and the engine is started when the accelerator is off or brake on. The stop is going on.

JP 2011-20571 A JP 2010-202119 A JP 2013-35336 A JP 2010-149783 A JP 2013-52802 A

  In Patent Literature 1, since the engine is repeatedly started and stopped only in response to the accelerator operation or the brake operation, if the accelerator operation or the brake operation is frequently performed, the engine is started or stopped frequently, and the engine is started or stopped. Frequent vibrations and noises that occur during driving make the driver feel uncomfortable.

  The present invention includes a first travel mode in which the vehicle travels and the power storage device is charged using the power of the engine, and a second travel mode in which the vehicle travels using the power of the power storage device while the engine is stopped. The purpose is to prevent the driver from feeling uncomfortable when the engine is started or stopped.

  The control device for a hybrid vehicle according to the present invention employs the following means in order to achieve the above-described object.

  The control device for a hybrid vehicle according to the present invention includes a first travel mode in which the vehicle is driven and the power storage device is charged using the power of the engine, and the vehicle travels using the power of the power storage device while the engine is stopped. In the second traveling mode, when the state of charge of the power storage device is equal to or lower than the charging threshold value, the accelerator is depressed and the vehicle requested driving force thereafter. On the condition that any of the increase occurs, the engine is started and switched to the first traveling mode, and in the first traveling mode, when the state of charge of the power storage device becomes equal to or greater than the discharge threshold value, After that, the engine is stopped and switched to the second traveling mode on condition that either the accelerator depressing back or the vehicle required driving force decrease occurs. That.

  In one aspect of the present invention, in the first traveling mode, when the state of charge of the power storage device is smaller than the discharge threshold value, it is preferable that the engine is not stopped even when either the accelerator depressing or the vehicle required driving force is reduced. It is.

  In one aspect of the present invention, in the second traveling mode, it is preferable that the engine is not started until either the accelerator is depressed or the vehicle required driving force increases even when the state of charge of the power storage device is equal to or less than the charging threshold. It is.

  According to the present invention, in the second travel mode, when the state of charge of the power storage device becomes equal to or lower than the charge threshold, the engine is operated on the condition that either accelerator depression or increase in vehicle required driving force has occurred thereafter. By starting the engine and switching to the first traveling mode, it is possible to suppress the driver from feeling uncomfortable by starting the engine while reducing the frequency of starting the engine. Then, in the first traveling mode, when the state of charge of the power storage device is equal to or higher than the discharge threshold value that is greater than the charge threshold value, on the condition that any of the accelerator depressing and the vehicle required driving force decrease occurs thereafter. By stopping the engine and switching to the second travel mode, it is possible to suppress the driver from feeling uncomfortable by stopping the engine while reducing the frequency of stopping the engine.

It is a figure which shows schematic structure of a hybrid vehicle provided with the control apparatus which concerns on embodiment of this invention. It is a functional block diagram which shows the structural example of the electronic controller for hybrids. It is a figure which shows an example of the characteristic of the vehicle request | requirement driving force Tp with respect to accelerator opening Ta. It is a figure which shows an example of the characteristic of the vehicle request | requirement driving force Tp with respect to the vehicle speed Vspd. It is a flowchart explaining an example of the process which the electronic controller for hybrids performs. FIG. 6 is a diagram illustrating an example of a temporal change of a vehicle speed Vspd, an accelerator opening degree Ta, and a state of charge SOC of a power storage device when the process of the flowchart of FIG. 5 is executed.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention (hereinafter referred to as embodiments) will be described with reference to the drawings.

  FIG. 1 is a diagram illustrating a schematic configuration of a hybrid vehicle including a control device according to an embodiment of the present invention. In the following description of the embodiment, the hybrid vehicle having the configuration shown in FIG. 1 will be described as an example. However, the hybrid vehicle to which the present invention can be applied is not limited to the configuration shown in FIG. A hybrid capable of selecting a first travel mode in which the vehicle is driven and the power storage device is charged using the power of the engine, and a second travel mode in which the vehicle is traveled using the power of the power storage device while the engine is stopped. The present invention can be applied to any vehicle.

  The engine 12 generates power by burning fuel. The power generated by the engine 12 is transmitted to the carrier C of the planetary gear mechanism (single pinion planetary gear) 32. The planetary gear mechanism 32 here functions as a power distribution mechanism that distributes the power transmitted to the carrier C to the sun gear S and the ring gear R. By transmitting the power distributed from the carrier C to the ring gear R to the drive shaft 17, it is possible to drive the vehicle by rotating the wheels 18 using the power of the engine 12. On the other hand, the power distributed from the carrier C to the sun gear S is transmitted to the motor generator 14 and converted into electric power generated by the power generation operation of the motor generator 14. The electric power generated by the motor generator 14 is supplied to the motor generator 15. At that time, a part of the power generated by the motor generator 14 is collected in the power storage device 20 such as a secondary battery to charge the power storage device 20, or the electric power stored in the power storage device 20 is used as the motor generator 15. It is also possible to supply The AC power supplied to the motor generator 15 is converted into power by the power running operation of the motor generator 15, and the power of the motor generator 15 is transmitted to the drive shaft 17, so that the wheels 18 are rotationally driven to drive the vehicle. Can be done.

  In the first travel mode in which the power of the engine 12 is used to travel the vehicle and the power storage device 20 is charged, the power distributed from the engine 12 to the ring gear R is transmitted to the wheels 18 and from the engine 12 to the sun gear. The power generation operation of the motor generator 14 is performed using the power distributed to S, and at least a part of the generated power of the motor generator 14 is recovered by the power storage device 20. Further, in the second travel mode (EV travel mode) in which the vehicle travels using the power of power storage device 20 while engine 12 is stopped, power running operation of motor generator 15 is performed using the power of power storage device 20. The power generated by the power running operation of the motor generator 15 is transmitted to the wheels 18.

  The operating state of the engine 12 is controlled by an engine electronic control unit (engine ECU) 40. The engine ECU 40 is in communication with a hybrid electronic control unit (hybrid ECU) 60, controls the operation of the engine 12 by a control signal from the hybrid ECU 60, and outputs data related to the operating state of the engine 12 to the hybrid ECU 60. The operating state of the motor generators 14 and 15 is controlled by a motor electronic control device (motor ECU) 50. The motor ECU 50 is also in communication with the hybrid ECU 60, controls the operation of the motor generators 14, 15 by a control signal from the hybrid ECU 60, and outputs data related to the operation state of the motor generators 14, 15 to the hybrid ECU 60. In hybrid ECU 60, a signal indicating voltage Vb of power storage device 20 detected by voltage sensor 61, a signal indicating current Ib of power storage device 20 detected by current sensor 62, and a vehicle speed Vspd detected by vehicle speed sensor 63 are indicated. The signal and the signal indicating the accelerator opening (depressed amount of the accelerator pedal) Ta detected by the accelerator opening sensor 64 are input.

  In the present embodiment, the average thermal efficiency is improved by alternately repeating the first traveling mode and the second traveling mode (hereinafter referred to as a high-speed cruise control mode) during high-speed cruise where the vehicle speed Vspd is equal to or higher than the set speed VSPD_HI. A functional block diagram of the hybrid ECU 60 for this purpose is shown in FIG. The charge state calculation unit 71 calculates the charge state (remaining capacity SOC of the secondary battery) of the power storage device 20. A known technique can be applied to a method for calculating the state of charge of the power storage device 20 (remaining capacity SOC of the secondary battery). For example, the calculation can be performed based on the voltage Vb and current Ib of the power storage device 20. The vehicle required driving force calculation unit 72 calculates the vehicle required driving force Tp by the driver and its time change rate dTp based on the accelerator opening degree Ta and the vehicle speed Vspd. For a constant vehicle speed Vspd, the required vehicle driving force Tp increases as the accelerator opening degree Ta increases (see, for example, FIG. 3). For a fixed accelerator opening degree Ta, the lower the vehicle speed Vspd decreases, the required vehicle drive. The vehicle required driving force Tp by the driver is calculated so that the force Tp slightly increases (see, for example, FIG. 4). Traveling mode switching unit 73 switches between the first traveling mode and the second traveling mode based on the state of charge SOC of power storage device 20 and the time change rate dTp of the vehicle required driving force in the high-speed cruise control mode.

  Next, a control routine in which the hybrid ECU 60 switches between the first travel mode and the second travel mode will be described with reference to the flowchart of FIG. The control routine according to the flowchart of FIG. 5 is repeatedly executed every predetermined time (for example, every several msec).

  First, in step S101, the vehicle required driving force Tp by the driver and its time change rate dTp are calculated by the vehicle required driving force calculator 72 based on the accelerator opening degree Ta and the vehicle speed Vspd. In step S102, it is determined whether or not the vehicle speed Vspd is equal to or higher than the set speed VSPD_HI. When Vspd <VSPD_H (when the determination result of step S102 is NO), the high-speed cruise control mode is not executed and this control routine is terminated. In this case, when the state of charge SOC of the power storage device 20 becomes equal to or less than the forced charge start threshold value SOC_C0, the power storage device 20 is charged using the power of the engine 12, and the charge state SOC of the power storage device 20 is set to the forced discharge start threshold value. When it becomes more than SOC_D0, the charge of the electrical storage apparatus 20 is stopped. On the other hand, when Vspd ≧ VSPD_HI (when the determination result in step S102 is YES), execution of the high-speed cruise control mode is permitted in step S103.

  In step S <b> 104, traveling mode switching unit 73 determines whether or not state of charge SOC of power storage device 20 is equal to or lower than charging threshold value SOC_CHG. The charging threshold SOC_CHG here is set to a value larger than the forced charging start threshold SOC_C0. If SOC ≦ SOC_CHG (if the determination result in step S104 is YES), the process proceeds to step S105. On the other hand, when SOC> SOC_CHG (when the determination result of step S104 is NO), the process proceeds to step S107.

  In step S105, the travel mode switching unit 73 determines whether the time change rate dTp of the vehicle required driving force is equal to or greater than the acceleration threshold value DTP_ACC (DTP_ACC> 0). When dTp <DTP_ACC (when the determination result of step S105 is NO), the present control routine is terminated without switching the travel mode. On the other hand, if dTp ≧ DTP_ACC (if the determination result in step S105 is YES), the first travel mode is selected by the travel mode switching unit 73 in step S106. When the first traveling mode is selected last time, the first traveling mode is maintained, and when the second traveling mode is selected last time, the second traveling mode is switched to the first traveling mode. When switching from the second travel mode to the first travel mode, the engine 12 is started.

  In step S107, travel mode switching unit 73 determines whether or not the state of charge SOC of power storage device 20 is equal to or greater than discharge threshold SOC_DCHG. Here, the discharge threshold SOC_DCHG is set to a value larger than the charge threshold SOC_CHG and smaller than the forced discharge start threshold SOC_D0. When SOC <SOC_DCHG (when the determination result of step S107 is NO), this control routine is terminated without switching the travel mode. On the other hand, if SOC ≧ SOC_DCHG (if the determination result in step S107 is YES), the process proceeds to step S108.

  In step S108, the travel mode switching unit 73 determines whether the time change rate dTp of the vehicle required driving force is equal to or less than the deceleration threshold value DTP_DEC (DTP_DEC <0). When dTp> DTP_DEC (when the determination result of step S108 is NO), this control routine is terminated without switching the travel mode. On the other hand, when dTp ≦ DTP_DEC (when the determination result in step S108 is YES), the second travel mode is selected by the travel mode switching unit 73 in step S109. When the second traveling mode is selected last time, the second traveling mode is maintained, and when the first traveling mode is selected last time, the first traveling mode is switched to the second traveling mode. When switching from the first travel mode to the second travel mode, the operation of the engine 12 is stopped.

  FIG. 6 shows an example of changes over time in the vehicle speed Vspd, the accelerator opening degree Ta, and the state of charge SOC of the power storage device 20 when the process of the flowchart of FIG. 5 is executed. In the example of FIG. 6, the second traveling mode is selected at time t1. In the second travel mode, the operation of the engine 12 is stopped, and the vehicle travels by performing the power running operation of the motor generator 15 using the electric power of the power storage device 20. In the second travel mode, the state of charge SOC of power storage device 20 gradually decreases due to the discharge of power storage device 20.

  At time t3, the state of charge SOC of the power storage device 20 decreases to the charging threshold SOC_CHG, but the accelerator opening degree Ta does not increase constantly (the accelerator is not depressed by the driver), and dTp <DTP_ACC is The vehicle request driving force Tp is not increased. In that case, the second traveling mode is maintained, the engine 12 is not started, and the switching to the first traveling mode is not performed. After time t2, the state of charge SOC of the power storage device 20 falls below the charging threshold SOC_CHG, but the accelerator opening degree Ta is constant or the accelerator opening degree Ta has decreased (the accelerator depressing operation by the driver is performed). When dTp <DTP_ACC is satisfied (the vehicle required driving force Tp has not increased), the second traveling mode is maintained, the engine 12 is not started, and the switching to the first traveling mode is performed. Not performed.

  At time t4, when the accelerator opening degree Ta increases (accelerator depression operation by the driver is performed) and the vehicle required driving force Tp increases so that dTp ≧ DTP_ACC is satisfied, the engine 12 is started and the second traveling mode is started. To the first travel mode. As described above, in the second traveling mode, even when the state of charge SOC of the power storage device 20 becomes equal to or less than the charging threshold SOC_CHG, the engine 12 is started until the accelerator opening degree Ta increases and dTp ≧ DTP_ACC is satisfied. Absent. In the first traveling mode, the power of the engine 12 is controlled to be larger than the vehicle required power Tp × Vspd, and the difference between the power of the engine 12 and the vehicle required power Tp × Vspd out of the generated power of the motor generator 14. The amount corresponding to is used for charging the power storage device 20. At that time, the torque and rotation speed of the engine 12 are controlled so that the engine efficiency becomes a predetermined high efficiency (for example, the highest thermal efficiency) with respect to the given engine power. In the first travel mode, the state of charge SOC of power storage device 20 gradually increases due to charging of power storage device 20.

  At time t2 prior to time t3, the accelerator opening degree Ta increases and the vehicle required driving force Tp increases so that dTp ≧ DTP_ACC is satisfied, but the state of charge SOC of the power storage device 20 is greater than the charging threshold SOC_CHG. Therefore, the second traveling mode is maintained, the engine 12 is not started, and the switching to the first traveling mode is not performed.

  At time t6, the state of charge SOC of the power storage device 20 increases to the discharge threshold SOC_DCHG, but the accelerator opening degree Ta is not constant and does not decrease (the accelerator is not depressed by the driver), and dTp> DTP_DEC Is established, and the vehicle required driving force Tp does not decrease. In that case, the first traveling mode is maintained, the operation of the engine 12 is not stopped, and the switching to the second traveling mode is not performed. After time t4, the state of charge SOC of the power storage device 20 exceeds the discharge threshold SOC_DCHG, but the accelerator opening degree Ta is constant or the accelerator opening degree Ta has increased (the accelerator depression operation by the driver is performed). When dTp> DTP_DEC is satisfied (the vehicle required driving force Tp has not decreased), the first traveling mode is maintained, the engine 12 is not stopped, and the switching to the second traveling mode is performed. Not performed.

  At time t7, when the accelerator opening degree Ta decreases (accelerator depressing operation by the driver is performed) and the vehicle required driving force Tp decreases so that dTp ≦ DTP_DEC is satisfied, the engine 12 is stopped, and the first The travel mode is switched to the second travel mode. As described above, in the first traveling mode, even if the state of charge SOC of the power storage device 20 becomes equal to or higher than the discharge threshold SOC_DCHG, the engine 12 is stopped until the accelerator opening degree Ta decreases and dTp ≦ DTP_DEC is satisfied. Not performed. At time t5 prior to time t6, the accelerator opening degree Ta decreases and the vehicle required driving force Tp decreases so that dTp ≦ DTP_DEC is satisfied, but the state of charge SOC of the power storage device 20 is greater than the discharge threshold SOC_DCHG. Therefore, the first traveling mode is maintained, the operation of the engine 12 is not stopped, and the switching to the second traveling mode is not performed.

  In the second traveling mode, when the state of charge SOC of the power storage device 20 becomes equal to or less than the forced charging start threshold SOC_C0, the engine 12 is started regardless of the condition of the vehicle required driving force Tp (accelerator opening degree Ta). And switch from the second travel mode to the first travel mode. Further, in the first traveling mode, when the state of charge SOC of the power storage device 20 becomes equal to or greater than the forced discharge start threshold SOC_D0, the engine 12 is stopped regardless of the condition of the vehicle required driving force Tp (accelerator opening degree Ta). To switch from the first travel mode to the second travel mode.

  According to the present embodiment described above, in the second traveling mode, even if the state of charge SOC of the power storage device 20 becomes equal to or lower than the charging threshold SOC_CHG, the engine 12 for charging the power storage device 20 is started only under that condition. The engine 12 is started and switched to the first travel mode on the condition that the increase in the vehicle required driving force Tp (dTp ≧ DTP_ACC) has occurred thereafter (without switching to the first travel mode). When the state of charge SOC of the power storage device 20 decreases and the power of the engine 12 is used to charge the power storage device 20, the engine 12 is started in accordance with the timing when the vehicle required driving force Tp by the driver increases. By doing so, it is possible to prevent the engine 12 from being started in a state where the vehicle required driving force Tp is constant or decreased, and to prevent the driver from feeling uncomfortable due to the engine starting unrelated to the driver's intention. . Further, until the state of charge SOC of the power storage device 20 becomes equal to or lower than the charging threshold SOC_CHG, the engine 12 is not started even if the vehicle required driving force Tp increases (dTp ≧ DTP_ACC). It is possible to suppress the frequent operation, and it is possible to prevent the driver from feeling uncomfortable due to the frequent occurrence of vibrations and noises that occur when starting the engine.

  In the first travel mode, even if the state of charge SOC of the power storage device 20 is equal to or higher than the discharge threshold SOC_DCHG, the engine 12 is not stopped for discharging the power storage device 20 only under that condition (second travel mode). Thereafter, the engine 12 is stopped and switched to the second traveling mode on condition that a decrease in the vehicle required driving force Tp (dTp ≦ DTP_DEC) occurs thereafter. When the state of charge SOC of the power storage device 20 is sufficiently large and the power storage device 20 is to be discharged, the vehicle 12 is driven by stopping the operation of the engine 12 at the timing when the vehicle required driving force Tp by the driver decreases. It is possible to prevent the engine 12 from being stopped while the force Tp is constant or increasing, and to prevent the driver from feeling uncomfortable due to the engine stop not related to the driver's intention. Further, until the state of charge SOC of the power storage device 20 becomes equal to or higher than the discharge threshold SOC_DCHG, even if a decrease in the vehicle required driving force Tp (dTp ≦ DTP_DEC) occurs, the operation of the engine 12 is not stopped. It is possible to prevent frequent stoppages, and it is possible to prevent the driver from feeling uncomfortable due to frequent occurrence of vibrations and noises that occur when the engine is stopped.

  In the present embodiment, in the second traveling mode, when the state of charge SOC of the power storage device 20 is equal to or lower than the charging threshold SOC_CHG, it is a condition that an accelerator depression (an increase in the accelerator opening degree Ta) has occurred thereafter. In addition, it is possible to start the engine 12 and switch to the first traveling mode. Even if the state of charge SOC of the power storage device 20 is equal to or less than the charging threshold SOC_CHG, the engine 12 is not started until the accelerator is depressed (increase in the accelerator opening Ta), and the accelerator is depressed by the driver (increase in the accelerator opening Ta). By starting the engine 12 in accordance with the timing, it is possible to prevent the engine 12 from being started when the accelerator opening degree Ta is constant or decreasing. Further, when the state of charge SOC of the power storage device 20 is larger than the charging threshold SOC_CHG, the engine 12 is not started even when the accelerator is depressed (increase in the accelerator opening degree Ta), so the engine 12 is frequently started. Can be deterred.

  In the first traveling mode, when the state of charge SOC of the power storage device 20 is equal to or higher than the discharge threshold SOC_DCHG, the engine 12 is operated on the condition that the accelerator is stepped back (the accelerator opening degree Ta is decreased) thereafter. It is also possible to stop the operation and switch to the second traveling mode. Even if the state of charge SOC of the power storage device 20 becomes equal to or greater than the discharge threshold SOC_DCHG, the operation of the engine 12 is not stopped until the accelerator is stepped back (decrease in the accelerator opening degree Ta). By stopping the operation of the engine 12 in accordance with the timing of the decrease in Ta, it is possible to prevent the operation of the engine 12 from being stopped while the accelerator opening degree Ta is constant or increasing. Further, when the state of charge SOC of the power storage device 20 is smaller than the discharge threshold SOC_DCHG, the engine 12 is not stopped even when the accelerator is stepped back (decrease in the accelerator opening degree Ta). It can be suppressed from being performed frequently.

  As mentioned above, although the form for implementing this invention was demonstrated, this invention is not limited to such embodiment at all, and it can implement with a various form in the range which does not deviate from the summary of this invention. Of course.

  12 engine, 14, 15 motor generator, 17 drive shaft, 18 wheels, 20 power storage device, 32 planetary gear mechanism, 40 engine electronic control device, 50 motor electronic control device, 60 hybrid electronic control device, 61 voltage sensor, 62 current sensor, 63 vehicle speed sensor, 64 accelerator opening sensor, 71 charge state calculation unit, 72 vehicle required driving force calculation unit, 73 travel mode switching unit.

Claims (3)

A hybrid capable of selecting a first travel mode in which the vehicle is driven and the power storage device is charged using the power of the engine, and a second travel mode in which the vehicle is traveled using the power of the power storage device while the engine is stopped. A control device for a vehicle,
In the second traveling mode, when the state of charge of the power storage device becomes equal to or less than the charging threshold, the engine is started and the first is started on the condition that either accelerator depression or vehicle required driving force increase occurs thereafter. Switch to driving mode,
In the first traveling mode, when the state of charge of the power storage device becomes greater than or equal to the discharge threshold value that is greater than the charge threshold value, the engine is operated on the condition that either the accelerator depressing or the vehicle required driving force is reduced thereafter The control apparatus of a hybrid vehicle which stops and switches to 2nd driving mode. The hybrid vehicle control device according to claim 1,
In the first travel mode, when the state of charge of the power storage device is smaller than the discharge threshold, the hybrid vehicle control device does not stop the engine even when either the accelerator depressing back or the vehicle required driving force is reduced. A control device for a hybrid vehicle according to claim 1 or 2,
In the second traveling mode, the hybrid vehicle control device does not start the engine until either the accelerator is depressed or the vehicle required driving force is increased even if the state of charge of the power storage device is equal to or less than the charging threshold.

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