JP6693407B2 - Hybrid vehicle - Google Patents

Description

  The present disclosure relates to a hybrid vehicle, and more particularly to control for switching between an electric drive mode and a hybrid drive mode.

BACKGROUND ART A hybrid vehicle including an internal combustion engine (engine) and an electric motor (motor) as a drive source for traveling has attracted attention as an environment-friendly vehicle.
In a hybrid vehicle, in order to reduce fuel consumption of the engine, and from the viewpoint of quietness, it is desirable to suppress running by driving the engine and give priority to running the motor by electric power supplied from the driving battery as much as possible.

In JP-A-2009-143563, an EV priority switch is provided, and the user can request switching between the EV priority mode and the HV (hybrid) mode. It is disclosed that “priority” in the EV priority mode means that the engine is stopped and the vehicle runs only using the motor generator without maintaining the SOC of the power storage device at a predetermined target value. (Patent Document 1, paragraph 0047).
Then, when the switching to the HV mode is requested by the traveling mode switching request switch in the EV priority mode, if the SOC of the power storage device is lower than the threshold value Sth1, the traveling mode is switched to the HV mode and the HV mode is set. The SOC is controlled in the vicinity of the SOC at the time of the request to switch to, and if the SOC is equal to or higher than the threshold value Sth1, the EV priority mode is maintained. Further, it is shown that when the SOC reaches the threshold value Sth2 smaller than the threshold value Sth1, the traveling mode is forcibly switched to the HV mode.

  Further, in Patent Document 2 (Japanese Patent Laid-Open No. 2013-154652), a first traveling mode in which only power generated by an electric motor driven by electric power from a drive battery is used, power generated by the electric motor, and internal combustion engine In the hybrid vehicle that travels in either one of the second travel mode using the generated power, when the charging rate of the drive battery becomes equal to or less than the first threshold value, the first travel mode is changed to the second travel mode. Switching to a drive mode is disclosed. Further, it is shown that the first threshold value is set to increase as the degree of deterioration of the driving battery increases.

JP, 2009-143563, A JP, 2013-154652, A

As described above, Patent Documents 1 and 2 disclose switching to a hybrid drive mode using engine power when the SOC (State of Charge) of the drive battery drops below a predetermined value. ..
However, there is no disclosure of delaying the timing of switching from EV traveling using an electric motor to hybrid traveling using engine power. In particular, in the case where the EV priority mode is switched to the hybrid drive by the engine drive when the voltage of the drive battery drops below a predetermined value, control for delaying the drop to the predetermined value voltage as much as possible is disclosed. It has not been.

  Further, one of the conditions for starting the engine during traveling in the EV priority mode is that the voltage of the driving battery drops below a predetermined value. This voltage drop of the driving battery cannot be recognized by the driver and causes the engine to start suddenly. For this reason, it is desirable to delay the voltage drop to a predetermined voltage as much as possible to prevent an unexpected engine start.

  Therefore, in view of the above technical problem, in at least one embodiment of the present invention, in a hybrid vehicle, when the EV priority switch is turned on and the vehicle is traveling in the electric traveling mode, the voltage value of the drive battery changes to the engine starting voltage. An object of the present invention is to delay the decrease, delay the timing from EV running to engine start, reduce the fuel consumption of the engine due to EV running, and maintain quietness.

(1) A hybrid vehicle according to at least one embodiment of the present invention travels using an electric traveling mode in which an electric motor is driven by only electric power from a drive battery for traveling, and engine power and power generated by the motor. In a hybrid vehicle having a hybrid drive mode,
When the EV priority switch requesting to prioritize the electric traveling mode and the EV priority switch are turned on and the electric traveling mode is prioritized, the electric traveling mode is canceled and the hybrid traveling mode is set. An electric drive mode release control section for switching the engine to drive the engine, wherein the electric drive mode release control section changes from the electric drive mode to the hybrid mode when the voltage of the drive battery drops below a first predetermined value. A canceling unit that switches to a traveling mode; and a canceling delay unit that delays the decrease to the first predetermined value when the voltage of the driving battery decreases to a second predetermined value higher than the first predetermined value, The release delay unit suppresses the current value to a predetermined current value when the voltage of the drive battery drops to the second predetermined value, thereby reducing the drive battery Characterized by being configured to delay the pressure drop.

According to the above configuration (1), the EV priority switch is turned on, the voltage of the drive battery decreases while traveling in the electric traveling mode, reaches the first predetermined value, and switches to the hybrid traveling mode to switch the engine. When the voltage of the drive battery decreases to a second predetermined value higher than the first predetermined value before starting the operation, the decrease to the first predetermined value is delayed, so that the vehicle is driven in the electric travel mode. It can be made to continue as much as possible.
As a result, the fuel consumption of the engine can be suppressed and the quietness due to the electric running can be maintained. Further, it is possible to reduce the frequency with which the driver cannot recognize and suddenly start the engine.

(2) In some embodiments, in the configuration (1), the second predetermined value is changed according to a rate of change of the battery temperature with respect to time.
According to the above configuration (2), since the second predetermined value is changed according to the rate of change of the battery temperature with respect to time, it is effective in protecting the drive battery by preventing battery deterioration due to increase in battery temperature. ..
The rate of change ΔT of the battery temperature with respect to time is calculated by ΔT = (current battery temperature−battery temperature at the start of electric running when the EV priority switch is ON) / electric running duration from when the EV priority switch is ON. To be done.

(3) In some embodiments, in the above configuration (2), the second predetermined value is changed to a higher voltage value as the temperature increase change rate increases.
According to the above configuration (3), the higher the temperature change rate, the earlier the temperature reaches a high temperature. Therefore, from the viewpoint of battery protection, current suppression control can be performed earlier to suppress deterioration of the drive battery.

(4) In some embodiments, in any one of the configurations (1) to (3), the predetermined current value is changed according to the maximum battery temperature.
According to the above configuration (4), the maximum temperature of the battery affects the deterioration of the battery. Therefore, by controlling the predetermined current value, that is, the maximum current value to be suppressed according to the maximum temperature, the deterioration protection of the battery is prevented. Is effective in.

(5) In some embodiments, in the configuration (4), the predetermined current value is reduced as the maximum battery temperature increases.
According to the above configuration (5), the suppression current value is lowered as the maximum battery temperature rises, which is effective for protection against deterioration of the driving battery.

(6) In some embodiments, in the above configuration (2) or (3), the rate of change of the battery temperature with time is a rate of change with time in the battery cell having the highest temperature among the plurality of battery cells. It is characterized by being.
According to the above configuration (6), since the detection data of the highest temperature battery cell among the plurality of battery cells is used, deterioration protection of the battery (each battery cell) is reliably performed.

(7) In some embodiments, in the above configuration (4) or (5), the maximum temperature of the battery temperature is the maximum temperature of the battery cell having the highest temperature among the plurality of battery cells. And
According to the above configuration (7), since the detection data of the highest temperature battery cell among the plurality of battery cells is used, deterioration protection of the battery (each battery cell) is reliably performed.

  According to at least one embodiment of the present invention, in the hybrid vehicle, while the EV priority switch is turned on and the vehicle is traveling in the electric traveling mode, the voltage value of the driving battery is delayed from decreasing to the engine starting voltage, By delaying the timing from EV running to engine start, it is possible to reduce the fuel consumption of the engine due to EV running and maintain quietness.

1 is an overall schematic diagram of a hybrid vehicle according to an embodiment of the present invention. It is explanatory drawing of the driving mode of a hybrid vehicle. FIG. 1 is a schematic configuration diagram of a control device for a hybrid vehicle according to an embodiment of the present invention. 3 is a control flowchart of a hybrid vehicle control device according to an embodiment of the present invention. 4 is a time chart showing a control state by a control device for a hybrid vehicle according to an embodiment of the present invention, in which (A) accelerator opening, (B) vehicle speed, (C) battery output, (D) battery voltage, (E) ) Battery current, (F) maximum cell temperature, (G) engine output, and (H) vehicle output are shown.

Hereinafter, some embodiments of the present invention will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes and relative arrangements of the components described in these embodiments or shown in the drawings are not intended to limit the scope of the present invention thereto, but merely illustrative examples. Nothing more.
For example, the expressions representing relative or absolute arrangements such as "in a certain direction", "along a certain direction", "parallel", "orthogonal", "center", "concentric", or "coaxial" are strict. In addition to representing such an arrangement, it also represents a state of relative displacement, or a state of relative displacement with an angle or distance such that the same function can be obtained. On the other hand, the expressions “comprising”, “comprising”, “comprising”, “including”, or “having” one element are not exclusive expressions excluding the existence of other elements.

A control device for a hybrid vehicle according to an embodiment of the present invention will be described with reference to FIG.
FIG. 1 shows a schematic configuration of a hybrid vehicle 1. Although FIG. 1 shows a vehicle in which a motor (electric motor) 3 is arranged on the front side and the rear side, the present invention is not limited to this.

As shown in FIG. 1, the hybrid vehicle 1 includes a power source 7 including an engine 5 and a motor 3 (front motor 3A, rear motor 3B), a fuel tank 9 for storing fuel supplied to the engine 5, and an engine 5 The generator (generator) 11 driven by the motor and the motor 3 (3A, 3B), and the driving battery (battery) 13 to which the electric power generated by the generator 11 is supplied, the engine 5, or the motor. 3 (3A, 3B) drive wheels 15 driven by power generated (front wheels 15A, rear wheels 15B), and a transaxle (power transmission that transmits power generated by the engine 5 or the motor 3 to the drive wheels 15). Device 17 (front transaxle 17A, rear transaxle 17B).
The engine 5 is arranged in front of the vehicle body, and the drive battery 13 is arranged under the floor at the center of the vehicle body.

  Further, the hybrid vehicle 1 according to the embodiment of the present invention includes a front motor ECU (Electronic Control Unit) 19 for controlling the front motor 3A and the generator 11, a rear motor ECU 21 for controlling the rear motor 3B, and an engine ECU 23 for controlling the engine 5. A battery ECU 25 for controlling the drive battery 13 is provided, and an integrated ECU 27 for controlling the front motor ECU 19, the rear motor ECU 21, the engine ECU 23, and the battery ECU 25 is further provided. These ECUs are connected by CAN (Controller Area Network) communication in the vehicle.

  The hybrid vehicle 1 according to the present embodiment has an EV traveling mode (electric traveling mode), a series traveling mode (hybrid traveling mode 1), or a parallel traveling mode (hybrid traveling mode 2) as traveling modes. Any one of the traveling modes can be arbitrarily selected, and the vehicle is configured to travel in any one of the traveling modes.

  The EV traveling mode is a traveling mode in which the motor 3 (3A, 3B) is driven by the electric power charged in the drive battery 13, as shown in FIG. 2 (A). Electric power is supplied from the drive battery 13 to the motor 3 (3A, 3B). As a result, the engine 5 is stopped, and the traveling wheels 15 (front wheels 15A, rear wheels 15B) are driven using only the motor 3 (3A, 3B) as a power source (referred to as "EV traveling").

  As shown in FIG. 2B, the series traveling mode is a traveling mode in which the engine 5 drives the generator 11 and the electric power generated by the generator 11 drives the motor 3 (3A, 3B). Electric power generated by the generator 11 driven by the engine 5 is supplied to the motor 3 (3A, 3B) and the driving battery 13. Thus, the engine 5 is operated, but the traveling wheels 15 (15A, 15B) are driven by the motor 3 (3A, 3B) as a power source (hybrid traveling mode 1).

The parallel traveling mode is a traveling mode in which the engine 5 and the motor 3 (3A, 3B) are used as the power source for traveling, as shown in FIG. 2 (C). The front wheel 15A is driven by the engine 5 and the front motor 3A, and the rear wheel 15B is driven by the rear motor 3B (hybrid traveling mode 2).
Furthermore, surplus power may be supplied to the driving battery 13 from the generator 11 driven by the engine 5.

  Further, the front transaxle 17A is provided with a clutch device 29, which controls connection and disconnection according to switching between the series traveling mode and the parallel traveling mode, and the clutch device 29 is engaged in the parallel traveling mode. The rotation of the output shaft of the engine 5 is transmitted to the front wheels 15A. In the series traveling mode, the clutch device 29 is disengaged and the rotation of the output shaft of the engine 5 is not transmitted to the front wheels 15A.

As described above, the battery ECU 25 is provided for the drive battery 13, and detects the temperature, the output voltage, the discharge current, and the state of charge (SOC) of the drive battery 13 to detect them. The information is transmitted to the integrated ECU 27.
Further, the battery ECU 25 is provided with a cell ECU 28 that detects a state of each cell forming the battery. The cell ECU 28 obtains temperature information from the temperature sensor 30 provided in each cell.

  An engine ECU 23 is provided for the engine 5, detects various kinds of information indicating the operating state of the engine, such as the amount of fuel supplied to the combustion chamber and the timing of the supply, and transmits the detected information to the integrated ECU 27. The ECU 23 controls the fuel supply amount and the supply timing to the combustion chamber of the engine 5 according to an instruction from the integrated ECU 27.

  A front motor ECU 19 is provided for the front motor 3A, and a rear motor ECU 21 is provided for the rear motor 3B. The torque information of each of the front motor 3A and the rear motor 3B is detected, and the detected information is transmitted to the integrated ECU 27. At the same time, the front motor ECU 19 and the rear motor ECU 21 are instructed by the integrated ECU 27 to operate the front motor 3A and the rear motor 3B respectively. Inverter control of each motor is performed to control the output torque of the motor.

Next, the integrated ECU (control device) 27 will be described.
As shown in FIGS. 1 and 2, the integrated ECU 27 is provided with a signal input unit, a signal output unit, a storage unit, a calculation unit, etc., which are not shown. The signal from the EV priority switch 31 is input to the signal input unit. The EV priority switch 31 is a switch operated by the driver in order to request that the EV traveling be prioritized for traveling as much as possible, that is, until a predetermined condition is satisfied.
The predetermined condition for canceling the EV traveling is, for example, when the depression amount of the accelerator is a certain value or more, when the SOC of the driving battery 13 drops below a certain value, and when the voltage value of the driving battery 13 falls below a certain value. There are various cases such as the case of a decrease. In this embodiment, EV traveling is canceled when the voltage value of the driving battery 13 drops below a certain level.

  In addition, signals from a vehicle state detection sensor mounted on the vehicle, such as a vehicle speed sensor 33 and an accelerator opening sensor 35, are input to the input signal section.

  As shown in FIG. 3, the integrated ECU 27 mainly includes an EV traveling mode release control unit 43, an EV traveling mode control unit 45, a series traveling mode control unit 47, and a parallel traveling mode control unit 49.

  The EV traveling mode control unit 45 includes signals from various sensors of the vehicle operating state, information on the current, voltage, SOC, etc. of the driving battery 13 from the battery ECU 25, information on torque, etc. from the front motor ECU 19, the rear motor ECU 21, Also, based on the information on the engine state from the engine ECU 23, the engine 5 is stopped and the running wheels 15 (front wheels 15A, rear wheels 15B) are driven by using only the motor 3 (3A, 3B) as a power source. The ECU 23, the front motor ECU 19, and the rear motor ECU 21 are instructed.

  The series traveling mode control unit 47 includes signals from various sensors of the vehicle operating state, further information such as the current, voltage and SOC of the driving battery 13 from the battery ECU 25, information such as torque from the front motor ECU 19 and the rear motor ECU 21, Also, based on the information on the engine state from the engine ECU 23, the electric power generated by the generator 11 driven by the engine 5 is supplied to the motor 3 (3A, 3B) and the driving battery 13, and the motor 3 (3A, 3B) as a power source to instruct the engine ECU 23, the front motor ECU 19, and the rear motor ECU 21 to drive the traveling wheels 15 (15A, 15B).

  The parallel traveling mode control unit 49 includes signals from various sensors of the vehicle operating state, information such as the current, voltage, SOC, etc. of the driving battery 13 from the battery ECU 25, information such as torque from the front motor ECU 19, the rear motor ECU 21, and the like. And the traveling wheels 15 (15A, 15B) are driven by the engine 5 and the motor 3 (3A, 3B) based on the information on the engine state from the engine ECU 23, and the generator 11 driven by the engine 5 drives a driving battery. The engine ECU 23, the front motor ECU 19, and the rear motor ECU 21 are instructed to supply the surplus power to 13.

  The EV traveling mode cancellation control unit 43 controls the drive of the engine 5 by canceling the EV traveling mode and switching to the series traveling mode (hybrid traveling mode 1) or the parallel traveling mode (hybrid traveling mode 2).

  When the EV priority switch 31 is ON, the EV traveling mode release control unit 43 causes the voltage of the drive battery 13 to reach a predetermined voltage value V1 (first predetermined value) and drop below it when traveling in the EV traveling mode. At some times, the voltage of the release unit 51 that drives the engine 5 by switching to the series traveling mode (hybrid traveling mode 1) or the parallel traveling mode (hybrid traveling mode 2) mode, and the voltage of the driving battery 13 is higher than the predetermined voltage value V1. And a release delay unit 53 that delays the decrease to the predetermined voltage value V1 when the voltage drops to the predetermined voltage value V2 (second predetermined value).

  In addition, in order to delay the voltage drop of the drive battery 13, the release delay unit 53 suppresses the discharge current value output from the drive battery 13 to a predetermined constant current value that is lower than the normal time. ing. As shown in FIG. 5E, the predetermined current value Im is suppressed to delay the voltage drop as shown in FIG. 5D. That is, normally, by lowering the current value that rises to maintain the output to the predetermined current value Im, the voltage rises due to the internal resistance of the drive battery 13 and the amount of current decrease, and the current consumption is further reduced. By being small, the voltage drop can be delayed. The predetermined current value Im means the maximum current value to be suppressed.

The integrated ECU 27 is adapted to automatically select a traveling mode so as to increase energy efficiency. For example, when traveling at a low or medium speed in a residential area or in a city, the EV traveling mode control unit 45 controls the driving in the EV traveling mode in which the vehicle is driven by the electric power of the driving battery 13.
Then, the integrated ECU 27 is one of the starting conditions for the engine 5 when acceleration is required or during high-speed traveling during operation in the EV traveling mode, and when the accelerator is depressed or the accelerator depression amount is constant. Based on the decrease in the output voltage of the driving battery 13, the EV drive mode cancellation control unit 43 automatically starts the operation of the engine 5 to supply electric power to the front motor 3A, the rear motor 3B, and the driving battery 13. The operation is switched to the series drive mode (hybrid drive mode 1) for supply. When the vehicle is traveling at a higher load and at a higher speed, the EV traveling mode cancellation control unit 43 causes the engine 5 to automatically start operating and travel using the driving force of the engine 5, and the front motor 3A and the rear motor 3B assist. Then, the operation is switched to the parallel traveling mode (hybrid traveling mode 2) in which the vehicle travels as a vehicle. In this parallel traveling mode, the drive battery 13 may be charged.
Further, the integrated ECU 27 uses the front motor 3A and the rear motor 3B as generators during deceleration, and regenerates deceleration energy to charge the drive battery 13.

Next, the control of the EV traveling mode cancellation control unit 43 will be described with reference to the control flowchart of FIG. 4 and the control time chart of FIG.
In the flowchart of FIG. 4, first, in step S1, it is determined whether or not the EV priority mode is in progress. That is, it is determined whether the EV priority switch 31 is turned on by the driver's intention and the EV traveling mode is in effect.

  If No, the process returns, and if Yes, the process proceeds to step S2 to update the battery temperature ΔT. That is, based on the information of each cell temperature from the cell ECU 28, the rate of change ΔT with respect to time is calculated from the temperature information of the highest temperature battery cell, and ΔT is updated for each calculation cycle. This ΔT is calculated by ΔT = (current battery cell temperature−battery temperature at the start of electric running when the EV priority switch is turned ON) / electric running duration from when the EV priority switch is turned ON.

Next, in step S3, the predetermined voltage value V2 (second predetermined value) is updated according to ΔT.
The predetermined voltage value V2 is updated to a higher predetermined voltage value V2 as ΔT increases, that is, as the temperature increase change rate increases. The predetermined voltage value V2 is a value higher than the engine starting voltage V1 and never falls below the engine starting voltage V1.
For this reason, the higher the rate of change in temperature, the higher the temperature will reach earlier. Therefore, from the viewpoint of battery protection, the predetermined voltage value V2 is made higher, and current suppression control is performed earlier to suppress deterioration of the drive battery. You can

In step S4, it is determined whether or not the battery voltage of the driving battery 13 is less than or equal to the updated predetermined voltage value V2. If No, the process returns to step S2, and if Yes, the process proceeds to step S5.
In step S5, the maximum temperature is detected from the temperature information of the battery cell having the highest temperature, based on the cell temperature information from the cell ECU 28. Then, in step S6, the predetermined current value Im is determined according to the maximum temperature.
The predetermined current value Im is updated so as to decrease as the maximum battery temperature increases. In this way, the predetermined current value Im, which is the suppression current value, is lowered as the maximum battery temperature rises, which is effective for protection against deterioration of the driving battery.

In step S7, the current is suppressed by changing to the determined predetermined current value Im. Then, in step S8, it is determined whether or not the engine start condition is satisfied. That is, it is determined whether or not the battery voltage has dropped below a predetermined voltage value V1 (first predetermined value). If it has fallen, the determination is Yes and the routine proceeds to step S9, where the mode is switched to the series traveling mode (hybrid traveling mode 1) or the parallel traveling mode (hybrid traveling mode 2) mode, and the engine 5 is started.
On the other hand, when the battery voltage has not dropped to the predetermined voltage value V1 in step S8, the process returns to step S5 and steps S5 to S8 are repeated.

Next, a control time chart will be described with reference to FIG.
In FIG. 5, (A) is the accelerator opening, (B) is the vehicle speed, (C) is the battery output, (D) is the battery voltage, (E) is the battery current, (F) is the maximum cell temperature, and (G) is Engine output and (H) indicate vehicle output, respectively.

As shown in FIG. 5 (A), the accelerator opening degree is increased by further pressing the accelerator (accelerator pedal) from time t0 to t1 during the EV traveling mode (in the EV priority mode) when the EV priority switch 31 is turned on. Shows a case where is a constant state.
As shown in FIG. 5 (B), the vehicle speed accelerates under further accelerator depression and constant accelerator depression.
As shown in FIG. 5 (C), the battery output of the driving battery 13 increases by further pressing the accelerator to reach the point Q at t1, and thereafter, the accelerator remains constant and the output continues until t2.

  As shown in FIG. 5 (D), the voltage of the driving battery 13 decreases due to the consumption of electric power due to EV traveling, and reaches a predetermined voltage value V2 at t2. At time t2 when the voltage has dropped to the predetermined voltage value V2, the current suppression is started. That is, as shown in FIG. 5 (E), the current is suppressed to the predetermined current value Im. As a result, as shown in FIG. 5D, the slope of the voltage decrease is moderated to delay the voltage decrease. That is, by reducing the current value to the predetermined current value Im, the voltage rise R due to the internal resistance of the driving battery 13 and the current decrease amount can be brought about, and the voltage decrease can be delayed because the current consumption is small. After the voltage R increases, the voltage decreases and reaches a predetermined voltage value V1 which is an engine starting voltage value, and the engine is started.

  As shown in FIG. 5 (E), the current rapidly increases to t1 when the accelerator is depressed, and then increases to t2 to maintain the battery output. Then, as described above, the current value Im is lowered to the predetermined current value Im at t2, and the predetermined current value Im is kept constant.

  As shown in FIG. 5 (F), the maximum cell temperature increases as the current increases. Then, after the current value is suppressed at t2, the temperature increase moderates and increases due to the current suppression. This highest cell temperature indicates the cell temperature in the highest temperature among the plurality of cells. The change rate ΔT with respect to time is calculated based on this maximum cell temperature.

As shown in FIG. 5 (G), the output of the engine 5 is lowered to the predetermined voltage value V1 which is the engine start voltage value because the EV priority switch 31 is ON and the EV running mode is in effect due to the driver's intention. Until then, the engine 5 is in a stopped state.
As shown in FIG. 5 (H), the vehicle output depends on only the output from the drive battery 13 until the engine is started at t3 because the EV priority switch 31 is ON and the EV traveling mode is in the driver's intention. The vehicle output, which changes according to the same tendency as the battery output in (C).

According to the present embodiment described above, the EV priority switch 31 is turned on, and the voltage of the drive battery 13 gradually decreases while traveling in the EV traveling mode, reaches a predetermined voltage value V1, and switches to the hybrid traveling mode. When the voltage of the driving battery 13 drops to a predetermined voltage value V2 higher than the predetermined voltage value V1 before the engine is started by the engine, the current (output) is suppressed and the decrease to the predetermined voltage value V1 is delayed. It is possible to continue traveling in the EV traveling mode as desired by the driver as much as possible.
As a result, the fuel consumption of the engine can be suppressed and the quietness due to the electric running can be maintained. Further, it is possible to reduce the frequency with which the driver cannot recognize and suddenly start the engine.

  Further, since the predetermined voltage value V2, which is the determination threshold value of the voltage of the driving battery 13, is changed according to the change rate ΔT of the battery temperature with respect to time, in particular, as the change rate ΔT of the temperature increase increases, the higher voltage value Therefore, the EV running mode can be continued as much as possible, and from the viewpoint of battery protection, the current can be suppressed earlier and the deterioration of the driving battery can be suppressed.

  Further, since the predetermined current value Im that reduces the current value to the predetermined voltage value V2 is changed according to the maximum temperature of the battery (battery cell), the maximum temperature of the battery (battery cell) becomes particularly high. Therefore, it is effective to protect the battery from deterioration by controlling the current suppression value according to the maximum temperature that affects the deterioration of the battery.

  Further, according to the present embodiment, the rate of change ΔT of the battery temperature with respect to time, and the maximum temperature of the battery cell is the rate of change ΔT and the maximum temperature of the battery cell showing the highest temperature among the plurality of battery cells. Therefore, deterioration protection of each battery cell can be surely performed.

  According to at least one embodiment of the present invention, when the EV priority switch is turned on and the vehicle is traveling in the EV traveling mode, the voltage value of the driving battery is delayed from being lowered to the engine starting voltage, so that the EV traveling can be stopped. By delaying the timing to the start and associating the drive battery temperature with the output suppression during EV traveling, it is possible to reduce the fuel consumption of the engine and maintain quietness. Suitable for use.

1 Hybrid vehicle 3 Motor (electric motor)
3A Front motor 3B Rear motor 5 Engine 13 Drive battery (battery)
19 Front motor ECU
21 Rear motor ECU
23 Engine ECU
25 Battery ECU
27 Integrated ECU
28-cell ECU
30 Temperature Sensor 31 EV Priority Switch 33 Vehicle Speed Sensor 35 Accelerator Opening Sensor 43 EV Driving Mode Release Control Unit 45 EV Driving Mode Control Unit 47 Series Driving Mode Control Unit 49 Parallel Driving Mode Control Unit 51 Release Unit 53 Release Delay Unit

Claims (3)

In a hybrid vehicle including an electric drive mode in which an electric motor is driven only by electric power from a drive battery to drive the vehicle, and a hybrid drive mode in which the vehicle is driven using the power generated by the engine and the electric power generated by the electric motor,
An EV priority switch that requests to prioritize the electric running mode;
When the EV priority switch is turned on and the electric traveling mode is prioritized, the electric traveling mode is canceled and the hybrid traveling mode is switched to to drive the engine. The electric drive mode release control unit,
A release unit that switches from the electric drive mode to the hybrid drive mode when the voltage of the drive battery drops below a first predetermined value;
And a release delay unit that delays the decrease to the first predetermined value when the voltage of the driving battery decreases to a second predetermined value higher than the first predetermined value,
The release delay unit is configured to delay the voltage drop of the driving battery by suppressing the current value to a predetermined current value when the voltage of the driving battery drops to the second predetermined value .
The hybrid vehicle, wherein the second predetermined value is changed to a higher voltage value as a rate of change in temperature rise, which is a rate of change in battery temperature with time, increases . The hybrid vehicle according to claim 1, wherein the predetermined current value is reduced as the maximum temperature of the battery cell having the highest temperature among the plurality of battery cells is increased . 3. The hybrid vehicle according to claim 1, wherein the rate of change of the battery temperature with respect to time is the rate of change with time of the battery cell having the highest temperature among the plurality of battery cells.

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