JP2013071622A - Control device for hybrid vehicle, and hybrid vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control device for a hybrid vehicle which is improved in power performance and fuel economy and mounted with a battery including a lithium ion secondary battery, and to provide a hybrid vehicle.SOLUTION: A control device for a vehicle includes: an adjustment power calculation section 460 calculating requested power Pchg* for bringing a battery charged state close to a target value within a range capable of being requested; a distribution processing section 480 performing power distribution between an engine and a motor generator on the basis of the total power Pt* and an input/output allowable power value to a battery; and a battery protection processing section 450. The battery protection processing section 450 changes the input/output allowable power value (Win or Wout) on the basis of the history of a charge/discharge current IB to the battery, and commands a change of the requested power Pchg* to the adjustment power calculation section 460 on the basis of the history of the charge/discharge current IB to the battery.

Description

  The present invention relates to a hybrid vehicle control device and a hybrid vehicle, and more particularly to a hybrid vehicle control device and a hybrid vehicle equipped with a battery including a lithium ion secondary battery.

  Some hybrid vehicles generate power using the power generated by the engine and charge the battery so that the state of charge of the battery is maintained within a predetermined range. This predetermined range is determined in consideration of battery life, energy efficiency, and the like.

  Japanese Patent Laying-Open No. 10-150701 (Patent Document 1) calculates a target value (target state SOC *) of a state of charge of a battery and performs a control so as to converge the state of the battery to the target state SOC *. Is disclosed.

JP-A-10-150701 International Publication No. 2010/005079 Pamphlet

  On the other hand, the application of lithium ion secondary batteries is being promoted as an in-vehicle power storage device. A lithium ion secondary battery has a high energy density and a high output voltage, and thus is suitable as an in-vehicle power storage device that requires a large battery capacity and a high voltage.

  However, depending on the mode of use, lithium ion secondary batteries may cause heat generation or performance degradation due to lithium metal deposition mainly on the negative electrode surface during continuous charging, or increase internal resistance mainly during continuous discharge. It is known that there is a risk of doing so. For this reason, the battery protection control of a lithium ion secondary battery is applied.

  As an example of this battery protection control, International Publication No. 2010/005079 (Patent Document 2) includes a history of charge / discharge to suppress precipitation of lithium metal on the negative electrode of a lithium ion secondary battery. Control for adjusting the input permission power to the battery is described. Specifically, it is described that the maximum current value at which lithium metal does not precipitate is sequentially calculated based on the battery current, and the input permission power to the battery is adjusted so that the battery current does not exceed the maximum current value. Has been.

  When the control for converging the SOC of the battery to the target SOC described in JP-A-10-150701 (Patent Document 1) and the battery protection control for the lithium ion secondary battery described above are applied to a hybrid vehicle at the same time, Due to the interference of the control, there is a concern about adverse effects on the power performance and fuel consumption of the vehicle.

  An object of the present invention is to provide a hybrid vehicle control device and a hybrid vehicle equipped with a battery including a lithium ion secondary battery in which the power performance and fuel consumption of the vehicle are improved.

  In summary, the present invention provides a control device for a hybrid vehicle equipped with an engine, a battery including a lithium ion secondary battery, and a motor generator configured to be capable of mutually transmitting rotational force between wheels. An adjustment power calculation unit for calculating a first required power for bringing the state of charge of the battery close to a target value within a requestable range based on the state of charge of the battery; a second required power required for traveling of the vehicle; A distribution processing unit for distributing power between the engine and the motor generator based on the total power of the requested power and the input / output permission power value to the battery, and a battery protection process for performing a protection process for protecting the battery A part. The battery protection processing unit changes the input / output permission power value based on the history of charge / discharge current to the battery, and the first required power to the adjustment power calculation unit based on the history of charge / discharge current to the battery. Instruct to change.

  Preferably, the battery protection processing unit sets the input / output permission power value to the first standard value when the magnitude of the charge / discharge current to the battery is smaller than the threshold value, and the magnitude of the charge / discharge current to the battery is a threshold. When the value is larger than the value, the input / output permission power value is limited to be lower than the first standard value as a protection process. When the difference between the magnitude of the charge / discharge current to the battery and the threshold value is smaller than a predetermined value, the battery protection processing unit instructs the adjustment power calculation unit to further limit the requestable range.

  More preferably, the input / output permission power value includes an input permission power value indicating an upper limit value of charging power to the battery. When the magnitude of the charging current to the battery is smaller than the charging threshold value, the battery protection processing unit sets the input permission power value to the first standard value, and the magnitude of the charging current to the battery is the charging threshold. When the value is larger than the value, a charge restriction processing unit that restricts the input permission power value to the battery from the first standard value is included as a protection process. When the difference between the magnitude of the charging current to the battery and the charging threshold value is smaller than a predetermined value, the charging restriction processing unit further restricts the charging upper limit value of the requestable range to the adjustment power calculation unit. To give instructions.

  More preferably, the input / output permission power value includes an output permission power value indicating an upper limit value of the discharge power of the battery. When the magnitude of the battery discharge current is smaller than the discharge threshold, the battery protection processing unit sets the output permission power value to the first standard value, and the magnitude of the battery discharge current is greater than the discharge threshold. If larger, a discharge limiting processing unit that limits the output permission power value from the first standard value is included as a protection process. When the difference between the magnitude of the discharge current of the battery and the discharge threshold value is smaller than a predetermined value, the discharge limit processing unit further limits the discharge upper limit value in the required range to the adjustment power calculation unit. Give instructions.

  More preferably, the vehicle further includes a braking device configured to apply a friction braking force to the wheels. The input / output permission power value includes an input permission power value indicating the upper limit value of the charging power to the battery and an output permission power value indicating the upper limit value of the discharge power of the battery. The distribution processing unit includes a drive torque distribution processing unit that distributes the drive torque between the engine and the motor generator based on the total power, the input permitted power value, and the output permitted power value, and the requested braking torque and the input permission. And a braking torque distribution processing unit that distributes the braking torque between the motor generator and the braking device based on the electric power value.

  In another aspect, the present invention is a hybrid vehicle including any one of the control devices described above.

  According to the present invention, it is possible to improve the power performance and fuel consumption of a hybrid vehicle equipped with a battery including a lithium ion secondary battery.

1 is a block diagram illustrating a schematic configuration of a hybrid vehicle shown as a representative example of a vehicle equipped with a vehicle control device according to an embodiment of the present invention. It is a functional block diagram of HV-ECU of FIG. It is a figure for demonstrating an example of the brake cooperative control by hydraulic braking and regenerative braking. It is a flowchart which shows the control processing procedure of the brake cooperation control in the hybrid vehicle 5 shown in FIG. It is a wave form diagram explaining Li precipitation suppression control performed with the hybrid vehicle 5 by embodiment of this invention. It is a flowchart explaining the setting process of Win by Li precipitation suppression control in the vehicle by embodiment of this invention. It is a flowchart for demonstrating the control processing for the traveling control of the hybrid vehicle of this Embodiment. It is a conceptual diagram for demonstrating the setting of an engine operating point. It is a flowchart for demonstrating the detail of the control processing for setting charging / discharging power Pchg *. It is a standard map for determining charging / discharging power Pchg *. It is a charge upper limit restriction map for determining charge / discharge power Pchg *. It is a discharge upper limit restriction map for determining charge / discharge power Pchg *. It is a wave form diagram for demonstrating the restriction intervention signal SIWin. FIG. 10 is an operation waveform diagram for explaining an operation when the charge / discharge power Pchg * is not limited (comparative example) in the present embodiment. It is an operation waveform diagram for explaining the operation when the charge / discharge power Pchg * is limited in the present embodiment. It is a figure for demonstrating the map which determines charging / discharging power Pchg * in a modification. It is a wave form chart for explaining change of Win and Pchg * in a modification.

  Embodiments of the present invention will be described below in detail with reference to the drawings. In the following, the same or corresponding parts in the drawings are denoted by the same reference numerals and description thereof will not be repeated.

[Description of overall vehicle configuration]
FIG. 1 is a block diagram illustrating a schematic configuration of a hybrid vehicle shown as a representative example of a vehicle equipped with a vehicle control device according to an embodiment of the present invention.

  Referring to FIG. 1, hybrid vehicle 5 includes drive wheels 12, a reduction gear 14, an engine 20, a first motor generator (hereinafter referred to as a first MG) 40 for power generation and engine start, and vehicle drive. Second motor generator (hereinafter referred to as second MG) 60, brake hydraulic circuit 80, power split mechanism 100, and transmission 200.

  The hybrid vehicle 5 includes a power control unit (PCU) 16, a battery 18 composed of a lithium ion secondary battery, a brake pedal 22, a brake ECU (Electronic Control Unit) 300, an HV-ECU 302, Engine ECU 304 and power supply ECU 306 are further included. Typically, each ECU is configured by a microcomputer including a CPU (Central Processing Unit), a memory, an input / output port, and a communication port (not shown). At least a part of each ECU may be configured to execute predetermined numerical / logical operation processing by hardware such as an electronic circuit.

  The brake ECU 300, the HV-ECU 302, the engine ECU 304, and the power supply ECU 306 are connected to be communicable with each other using a communication bus 310. In the present embodiment, the brake ECU 300, the HV-ECU 302, the engine ECU 304, and the power supply ECU 306 have been described as separate ECUs, but these ECUs are integrated into fewer ECUs than in the current situation. Alternatively, it may be divided into ECUs having a larger number than the current state.

  An IG switch 36 is connected to the power supply ECU 306. The power supply ECU 306 is provided with an IG relay (or an IG relay not shown) on condition that the brake pedal 22 is depressed when the driver performs an operation to activate the system of the hybrid vehicle 5 with respect to the IG switch 36. ACC relay) is turned on. In response to this, power is supplied to the electric device group constituting the hybrid vehicle 5 so that the hybrid vehicle 5 can travel.

  The engine 20 is a known internal combustion engine that outputs power by burning fuel such as a gasoline engine or a diesel engine, and electrically operates the operating state such as the throttle opening (intake amount), the fuel supply amount, and the ignition timing. It is configured to be controllable. A signal indicating the rotational speed Ne of the engine 20 is transmitted from the engine 20 to the engine ECU 304.

  The engine ECU 304 is configured so that the engine 20 operates at a target rotational speed and a target torque determined by the HV-ECU 302 based on signals from various sensors including an engine rotational speed sensor provided in the engine 20. 20 fuel injection amount, ignition timing, intake air amount and the like are controlled.

  The battery 18 includes a lithium ion secondary battery. Lithium ion secondary batteries have high energy density and higher initial circuit voltage and average operating voltage than other secondary batteries, and are therefore suitable for in-vehicle power storage devices for vehicles that require large battery capacity and high voltage. In addition, the lithium ion secondary battery has high charge / discharge efficiency because the Coulomb efficiency is close to 100%, and thus has an advantage that energy can be effectively used compared to other secondary batteries.

  However, as shown in Patent Document 2, lithium ion secondary batteries may deposit lithium metal on the negative electrode surface depending on the charging conditions. For this reason, in the present embodiment, similarly to Patent Document 2, control for limiting charging to the battery 18 in order to suppress lithium metal deposition in the lithium ion secondary battery (hereinafter referred to as “Li precipitation suppression control”). To be executed).

  The battery 18 is provided with a battery sensor 19 for detecting the state value of the battery 18. For example, the battery sensor 19 is configured to detect a battery current IB, a battery voltage VB, and a battery temperature TB as state values. The state value detected by the battery sensor 19 is transmitted to the HV-ECU 302.

  In the following, it is assumed that the battery current IB has a positive value (IB> 0) when the battery 18 is discharged, and a negative value (IB <0) when charged. The HV-ECU 302 can grasp the charge / discharge history of the battery 18 based on the battery current IB transmitted sequentially.

  Each of first MG 40 and second MG 60 is, for example, a three-phase AC rotating electric machine, and has a function as an electric motor (motor) and a function as a generator (generator).

  The first MG 40 and the second MG 60 are provided with rotational position sensors 41 and 42 for detecting the rotational position (angle) of the rotor (not shown), respectively.

  First MG 40 and second MG 60 are connected to battery 18 via power control unit (PCU) 16. The PCU 16 has an inverter and / or converter that includes a plurality of power semiconductor switching elements (not shown). The PCU 16 performs bidirectional power conversion between the first MG 40 and the second MG 60 and the battery 18 in accordance with a control instruction from the HV-ECU 302. The HV-ECU 302 controls power conversion in the PCU 16 so that the output torque of the first MG 40 and the output torque of the second MG 60 match the torque command values.

  Power split device 100 is a planetary gear provided between engine 20 and first MG 40. The power split mechanism 100 splits the power input from the engine 20 into power to the first MG 40 and power to the reduction gear 14 connected to the drive wheels 12 via the drive shaft 164. A vehicle speed sensor 161 is provided on the drive shaft 164. Based on the rotational speed of the drive shaft 164 detected by the vehicle speed sensor 161, the vehicle speed V of the hybrid vehicle 5 is detected.

  Power split device 100 includes a first ring gear 102, a first pinion gear 104, a first carrier 106, and a first sun gear 108. The first sun gear 108 is an external gear connected to the output shaft of the first MG 40. The first ring gear 102 is an internal gear arranged concentrically with the first sun gear 108. The first ring gear 102 is connected to the reduction gear 14 via a ring gear shaft 102 a that rotates together with the first ring gear 102. First pinion gear 104 meshes with each of first ring gear 102 and first sun gear 108. The first carrier 106 holds the first pinion gear 104 so as to rotate and revolve, and is connected to the output shaft of the engine 20.

  That is, the first carrier 106 is an input element, the first sun gear 108 is a reaction force element, and the first ring gear 102 is an output element. Then, the driving force (torque) output to the ring gear shaft 102 a is transmitted to the drive wheels 12 via the reduction gear 14 and the drive shaft 164.

  During the operation of the engine 20, when the reaction torque generated by the first MG 40 is input to the first sun gear 108 with respect to the output torque of the engine 20 input to the first carrier 106, the torque having a magnitude obtained by adding and subtracting these torques. Appears in the first ring gear 102 which is an output element. In that case, the first MG 40 functions as a generator because the rotor of the first MG 40 is rotated by the torque. When the rotation speed (output rotation speed) of the first ring gear 102 is constant, the rotation speed of the engine 20 can be changed continuously (steplessly) by changing the rotation speed of the first MG 40. . That is, control for setting the engine speed to, for example, the speed with the best fuel efficiency can be performed by controlling first MG 40. The control is performed by the HV-ECU 302.

When the engine 20 is stopped while the hybrid vehicle 5 is traveling, the second MG 60 rotates in the forward direction while the first MG 40 rotates in the reverse direction. When the first MG 40 is caused to function as an electric motor and torque is output in the forward rotation direction from that state, the torque in the forward rotation direction can be applied to the engine 20 connected to the first carrier 106. Therefore, the engine 20 can be started (motored or cranked) by the first MG 40. In that case, torque in a direction to stop the rotation acts on the reduction gear 14. Therefore, the driving force for running the vehicle can be maintained by controlling the output torque of the second MG 60, and at the same time, the engine 20 can be started smoothly. The hybrid type of the hybrid vehicle 5 shown in FIG. 1 is called a mechanical distribution type or a split type.

  During regenerative braking of the hybrid vehicle 5, the second MG 60 is driven by the drive wheels 12 via the reduction gear 14 and the transmission 200, so that the second MG 60 operates as a generator. Thereby, 2nd MG60 acts as a regenerative brake which converts braking energy into electric power. The electric power generated by the second MG 60 is stored in the battery 18 via the PCU 16. Since the power generated by the second MG 60 is determined by the product of the torque and the rotation speed of the second MG 60, the power generated by regenerative braking can be adjusted by the torque of the second MG 60.

  The transmission 200 is a planetary gear provided between the reduction gear 14 and the second MG 60. The transmission 200 changes the rotation speed of the second MG 60 and transmits it to the reduction gear 14. The transmission 200 may be omitted and the output shaft of the second MG 60 may be directly connected to the reduction gear 14.

  Transmission 200 includes a second ring gear 202, a second pinion gear 204, a second carrier 206, and a second sun gear 208. Second sun gear 208 is an external gear connected to the output shaft of second MG 60. Second ring gear 202 is an internal gear arranged concentrically with respect to second sun gear 208. The second ring gear 202 is connected to the reduction gear 14. Second pinion gear 204 meshes with each of second ring gear 202 and second sun gear 208. The second carrier 206 holds the second pinion gear 204 so as to rotate and revolve freely. The second carrier 206 is fixed to a case or the like (not shown) so as not to rotate.

  The transmission 200 uses the friction engagement element to limit the rotation of each element of the planetary gear based on the control signal from the HV-ECU 302 or to synchronize the rotation so that the rotation speed of the second MG 60 is one step. Alternatively, the gear may be shifted in a plurality of stages and transmitted to the reduction gear 14.

  The HV-ECU 302 executes travel control for performing travel suitable for the vehicle state. For example, when the vehicle starts and travels at a low speed, the hybrid vehicle 5 travels with the engine 20 stopped by the output of the second MG 60. During steady running, the hybrid vehicle 5 starts with the engine 20 and runs with the outputs of the engine 20 and the second MG 60. In particular, the fuel efficiency of the hybrid vehicle 5 is improved by operating the engine 20 at a highly efficient operating point. Specifically, the HV-ECU 302 reflects the accelerator pedal operation amount ACC detected by the accelerator pedal operation amount detection unit 34 to set the required driving force of the entire vehicle and realize the above-described travel control. As described above, the operation command values (typically, the rotational speed command value and / or the torque command value) of the engine 20, the first MG 40, and the second MG 60 are set.

  Further, the HV-ECU 302 estimates an SOC (State of Charge) of the battery 18 based on state values (battery current IB, battery voltage VB, battery temperature TB) detected by a battery sensor provided in the battery 18. . The SOC is indicated by a value indicating the current charge amount with respect to the full charge amount as a percentage. Since any known method can be applied to the SOC estimation method, detailed description will not be repeated.

  Further, the HV-ECU 302 is based on at least the SOC, and an input permission power value (hereinafter also referred to as “Win”) indicating a limit value of power charged in the battery 18 and an output permission indicating a limit value of power discharged from the battery 18. A power value (hereinafter also referred to as Wout) is set. Input / output power to the battery 18 (hereinafter also simply referred to as “battery power”) is a positive value when the battery 18 is discharged, and a negative value when charging. Therefore, Wout is zero or a positive value (Wout ≧ 0), and Win is zero or a negative value (Win ≦ 0). The HV-ECU 302 sets the operation command values of the first MG 40 and the second MG 60 by limiting the battery power to fall within the power range of Win to Wout.

Next, the brake system of the hybrid vehicle 5 will be described.
The braking device 10 includes a brake caliper 160 and a disc-shaped brake disc 162. The brake disc 162 is fixed to the drive shaft 164 so that the rotation axis thereof coincides. Brake caliper 160 includes a wheel cylinder and a brake pad (not shown). When the hydraulic pressure is supplied from the brake hydraulic pressure circuit 80 to the brake caliper 160, the wheel cylinder operates. The actuated wheel cylinder presses the brake pad against the brake disc 162, so that the rotation of the brake disc 162 is limited. As a result, the braking device 10 generates a hydraulic braking force corresponding to the supply hydraulic pressure Pwc from the brake hydraulic circuit 80.

  The brake fluid pressure circuit 80 includes a fluid pressure sensor 82 for detecting the fluid pressure Pwc supplied to the braking device 10 and a brake pedal operation amount detector 84 that detects the operation amount of the brake pedal 22. Furthermore, the brake fluid pressure circuit 80 includes a fluid pressure control actuator (typically a control valve) (not shown) that is controlled in accordance with an operation command from the brake ECU 300. The brake ECU 300 controls the hydraulic pressure Pwc supplied to the braking device 10 by opening / closing control or opening degree control of these control valves.

  The brake pedal operation amount detection unit 84 is configured by, for example, a pressure sensor that detects a master cylinder pressure output from a master cylinder (not shown). The master cylinder is connected to the brake pedal 22 and generates a hydraulic pressure corresponding to the operation amount of the brake pedal 22 of the driver. Alternatively, the brake pedal operation amount detection unit 84 may be configured by a stroke sensor that directly detects the operation amount of the brake pedal 22. The brake ECU 300 can detect an operation amount of the brake pedal 22 by the driver based on a signal from the brake pedal operation amount detection unit 84.

  In the hybrid vehicle 5, the required braking force (total braking force) for the entire vehicle corresponding to the operation of the brake pedal 22 by the driver is divided and output by the regenerative braking force by the second MG 60 and the hydraulic braking force by the braking device 10. The brake coordination control is executed.

FIG. 2 is a functional block diagram of the HV-ECU of FIG.
Referring to FIG. 2, HV-ECU 302 includes a required torque calculation unit 410, an SOC estimation unit 420, and a Win / Wout standard value calculation unit 430. The required torque calculation unit 410 includes a required drive torque calculation unit 414 and a required braking torque calculation unit 412.

  The HV-ECU 302 further includes a lithium battery protection processing unit 450, an SOC adjustment power calculation unit 460, a required power calculation unit 440, an addition unit 470, and a distribution processing unit 480. The lithium battery protection processing unit 450 includes a charge limitation processing unit 452 for suppressing lithium deposition and a discharge limitation processing unit 454 for suppressing discharge at a high rate.

  Distribution processing unit 480 includes a braking torque distribution processing unit 482, a drive torque distribution processing unit 483, and a motor torque addition unit 488. Drive torque distribution processing unit 483 includes an engine operating point determination unit 484 and a torque correction unit 486.

[Description of brake coordination control and battery protection processing by regenerative braking]
FIG. 3 is a diagram for explaining an example of brake cooperative control by hydraulic braking and regenerative braking. The control shown in FIG. 3 is mainly executed in the braking torque distribution processing unit 482 in FIG.

  2 and 3, line W10 indicates the total braking force (corresponding to braking torque Trb *) based on the driver's brake pedal operation. On the other hand, the line W20 indicates the regenerative braking force (corresponding to the braking torque Tmb *) generated by the second MG 60. It is understood that the total braking force is secured by the sum of the regenerative braking force and the hydraulic braking force (corresponding to the braking torque Tb *). Although not shown, in a hybrid vehicle equipped with an engine, in addition to the above-described hydraulic braking force and regenerative braking force, engine braking force by so-called engine braking is also generated. Therefore, strictly speaking, the regenerative braking force and the hydraulic braking force are determined in consideration of the engine braking force as necessary. However, in the following, in order to simplify the description, the description will be made assuming that the engine braking force = 0.

  Here, the regenerative braking force, that is, the braking torque output by the second MG 60 is limited within a range where the input power Pb to the battery 18 does not exceed Win (that is, within a range where Pb> Win). Therefore, when Win is limited, there is a possibility that the amount of recovered regenerative power may be reduced without generating the original regenerative braking force. In particular, when the Li precipitation suppression control shown in Patent Document 2 is applied, Win may change in the positive direction while the regenerative braking force is generated. In this case, in order to protect the battery 18, it is necessary to quickly reduce the regenerative braking force.

  Therefore, in the vehicle according to the present embodiment, the limit of regenerative power in the brake cooperative control considering the compatibility with the Li deposition suppression control is set as follows.

  FIG. 4 is a flowchart showing a control processing procedure of brake cooperative control in the hybrid vehicle 5 shown in FIG.

  The control process according to the flowchart shown in FIG. 4 is executed by the HV-ECU 302 at regular intervals. Further, each step shown in FIG. 4 is realized by software processing and / or hardware processing by the HV-ECU 302.

  Referring to FIG. 3, HV-ECU 302 inputs the vehicle state of hybrid vehicle 5 in step S100. The vehicle state includes a brake pedal operation amount BP that is an operation amount of the brake pedal 22, a vehicle speed V, a rotation speed Nm1 of the first MG 40, and a rotation speed Nm2 of the second MG 60.

  The brake pedal operation amount BP is detected based on the output of the brake pedal operation amount detection unit 84 in FIG. The vehicle speed V is detected based on the output of the vehicle speed sensor 161. The rotational speeds Nm1 and Nm2 are calculated based on the outputs of the rotational position sensors 41 and 42 attached to the first MG 40 and the second MG 60.

  In step S110, HV-ECU 302 sets the required braking torque Trb * for the entire vehicle based on the vehicle state of hybrid vehicle 5. The required braking torque Trb * corresponds to the total braking force shown in FIG. The required braking torque Trb * is calculated by the required braking torque calculation unit 412 in FIG.

  Typically, the required braking torque Trb * is calculated as the braking torque to be output to the ring gear shaft 102a based on the brake pedal operation amount BP and the vehicle speed V input in step S100. For example, a map in which the relationship between the brake pedal operation amount BP and the vehicle speed V and the required braking torque Trb * is determined in advance can be created in advance and stored in a memory (not shown) in the HV-ECU 302. In step S110, the required braking torque Trb * can be set by referring to the map based on the brake pedal operation amount BP and the vehicle speed V input in step S100.

  Subsequently, the HV-ECU 302 reads the Win of the battery 18 in step S120. The control process for setting Win will be described in detail later. | Win | (Win ≦ 0) indicates the maximum value of the charging power of the battery 18 at the present time (the control cycle), that is, the “charging power upper limit value”. Further, the magnitude (| IB |) of the battery current IB at the time of charging (IB <0) is also expressed as “charging current” below.

  In step S130, the HV-ECU 302 determines the amount of regenerative braking torque Tmb * of the requested braking torque Trb * according to the brake coordination control shown in FIG. A torque command value (second MG torque Tm2 *) of the second MG 60 that generates the regenerative braking force is set based on this shared amount.

  During regenerative braking, second MG 60 generates electric power according to the product of torque and rotational speed. Therefore, it is necessary to prevent the battery power (Pb = VB · IB) from exceeding the Win read in step S120. That is, it is necessary that | Pb | <| Win |. Therefore, in step S130, the second MG torque Tm2 * for brake cooperative control is set after being limited to a range where | Pb | <| Win |. Therefore, the amount of energy for recovering the kinetic energy of the vehicle as regenerative power is reduced by the amount limited by Win.

  Further, in step S140, the HV-ECU 302 sets the hydraulic brake torque Tb * according to the following equation (1). Note that Gr in equation (1) is a reduction ratio of the transmission 200.

Tb * = Trb * −Tmb * · Gr (1)
In this way, the brake cooperative control in which the required braking torque Trb * is shared by the regenerative braking torque (Tmb *) and the hydraulic brake torque (Tb *) is realized.

  Further, in step S150, the HV-ECU 302 outputs the hydraulic brake torque Tb * set in step S140 to the brake ECU 300 (FIGS. 1 and 2). The above braking torque distribution processing is executed by the braking torque distribution processing unit 482 in FIG.

  The brake ECU 300 calculates a target hydraulic pressure to be supplied to the braking device 10 based on the hydraulic brake torque Tb *. Then, the brake fluid pressure circuit 80 is controlled so that the supply fluid pressure Pwc detected by the fluid pressure sensor 82 matches the target fluid pressure.

  Next, Li deposition suppression control for the battery 18 constituted by a lithium ion secondary battery will be described.

  FIG. 5 is a waveform diagram for explaining the Li precipitation suppression control executed in the hybrid vehicle 5 according to the embodiment of the present invention.

  Referring to FIG. 5, battery current IB changes in the negative direction from time t0, and charging of battery 18 is started.

  The allowable input current value Ilim of the battery 18 is set according to the charge / discharge history of the battery 18. As described in Patent Document 2, the allowable input current value Ilim is obtained as the maximum current value at which lithium metal does not precipitate when the battery negative electrode potential decreases to the lithium reference potential within a unit time. The allowable input current value Ilim can be set similarly to Patent Document 2. That is, from the initial value Ilim [0] of the allowable input current value in a state where there is no charge / discharge history, by adding / subtracting a decrease amount due to continued charging, a recovery amount due to continued discharge, or a recovery amount due to neglecting for each control cycle, time Ilim [t] at t is sequentially obtained.

  Further, a margin current ΔImr with respect to the allowable input current value Ilim is set to set an input current limit target value Itag for preventing lithium metal deposition. As described in Patent Document 2, the input current limit target value Itag can be set by offsetting the allowable input current value Ilim in the positive direction. In this case, the offset current value becomes the margin current ΔImr.

As shown in FIG. 5, the allowable input current value Ilim and the input current limit target value Itag gradually change in the positive direction by continuous charging. As a result, it is understood that the allowable charging current (| IB |) is reduced. At time t1, IB is Itag
If it becomes lower than (IB <Itag), it becomes necessary to limit the charging current in order to suppress the precipitation of lithium metal.

  For this reason, as shown in FIG. 6, charging power (that is, regenerative power) is limited by changing Win of battery 18 in the positive direction from time t1. For example, Win is changed in the positive direction at a constant rate (time change rate). As a result, | Win |, that is, the “charging power upper limit value” decreases. The Win change rate at this time is also referred to as a “regeneration limit rate” below. The regeneration limit rate corresponds to an example of the degree of restriction in charging power limitation (hereinafter also referred to as “regeneration limitation”) by Li deposition suppression control.

  Referring to FIG. 5 again, the charging current decreases due to the limitation of Win from time t1 (that is, IB changes in the positive direction), and IB> Itag again at time t2. Thereby, as shown in FIG. 5, the regeneration restriction is released from time t2. As a result, the Win of the battery 18 gradually returns to the normal value.

  As described above, during regenerative braking in which a large charging current is generated, when the charging current reaches the input current limit target value Itag, the regenerative restriction that changes Win at a constant regenerative restriction rate is performed to suppress lithium metal deposition. Is started. As can be understood from FIG. 5, the larger the margin current ΔImr is, the more severe the regenerative restriction start condition is. On the other hand, when the margin current ΔImr is reduced, the energy recovered by the regenerative power generation can be increased by relaxing the regenerative restriction start condition.

  If Win changes due to regenerative braking during regenerative braking, the processing of steps S120 and S130 in FIG. 4 (braking torque distribution processing unit 482 in FIG. 2) reduces the sharing of regenerative braking torque (the absolute value of MG2 torque). Along with this decrease, the share of the hydraulic brake torque Tb * increases. In response to this, the brake ECU 300 controls the brake hydraulic pressure circuit 80 so as to increase the supply hydraulic pressure Pwc to the braking device 10.

  Such a decrease in the share of regenerative power due to the intervention of the Li precipitation suppression control leads to a deterioration in fuel consumption, so it is desirable that it does not occur as much as possible. In this embodiment, as will be described later with reference to FIG. 9, the charging / discharging power Pchg * is limited so as to avoid the intervention of the Li precipitation suppression control as much as possible.

  In the present embodiment, as described below, the regeneration limit rate in the Li deposition suppression control is variably set based on the vehicle speed and the battery state.

  FIG. 6 is a flowchart for explaining the Win setting process by the Li precipitation suppression control in the vehicle according to the embodiment of the present invention.

  The control process according to the flowchart shown in FIG. 6 is executed by the HV-ECU 302 at regular intervals. Further, each step shown in FIG. 6 is realized by software processing and / or hardware processing by the HV-ECU 302.

  Referring to FIG. 6, HV-ECU 302 inputs vehicle speed V of hybrid vehicle 5 in step S200. The vehicle speed V can be detected based on the output of the vehicle speed sensor 161 shown in FIG.

  Furthermore, HV-ECU 302 inputs the state value of battery 18 based on the output of battery sensor 19 in step S210. As described above, the state value input in step S210 includes, for example, voltage VB, current IB, and temperature TB of battery 18.

  In step S220, the HV-ECU 302 calculates the SOC of the battery 18. The processes in steps S210 and S220 described above are executed by the SOC estimation unit 420 in FIG.

  Furthermore, HV-ECU 302 sets Win0 of battery 18 in step S230. Win0 is Win before executing the regeneration limit rate process, and is set based on the current battery state (SOC, state value, etc.) without taking Li precipitation suppression control into consideration. That is, this Win0 corresponds to the Win of the battery 18 that is normally set based on a known method. For example, Win0 is set based on SOC and battery temperature TB. The process of step S230 described above is executed by the Win / Wout standard value calculation unit 430 in FIG.

  In step S240, the HV-ECU 302 sets the regeneration limit rate and the margin current based on the Li deposition suppression control based on the vehicle speed and the battery state. The regeneration limit rate corresponds to the change rate (time change rate) of Win in the positive direction shown at times t1 to t2 in FIG.

  It should be noted that the regeneration limit rate and the margin current are preferably made variable according to the vehicle speed V, the state of charge SOC, and the battery temperature TB.

  Subsequently, in step S250, the HV-ECU 302 executes a current control calculation for Li precipitation suppression control. That is, as described in FIG. 5, based on the method shown in Patent Document 2, the allowable input current value Ilim [t] in the current control cycle is calculated based on the charge / discharge history of the battery 18. Then, the input current limit target value Itag is calculated by providing the margin current ΔImr set in step S240 with respect to the allowable input current value Ilim.

  Further, in step S260, the HV-ECU 302 compares the battery current IB input in step S210 with the input current limit target value Itag calculated in step S250.

  Then, when IB> Itag (when NO is determined in S260), HV-ECU 302 turns off the regenerative restriction in step S270 because the charging current has not reached Itag. In this case, in step S275, Win0 set in step S230 becomes the Win of battery 18 as it is (Win = Win0).

  On the other hand, when IB <Itag (when YES is determined in S260), HV-ECU 302 turns on regeneration limitation in step S280 because the charging current has reached Itag. This is because IB may reach the allowable input current value Ilim unless the charging current is reduced from the current level.

  When the regeneration limit is turned on, HV-ECU 302 sets Win according to the regeneration limit rate set in step S240 in step S285. Specifically, Win is set so as to change in the positive direction according to the regeneration limit rate from Win in the previous control cycle. As the charging power upper limit value (| Win |) of the battery 18 decreases according to the regeneration limit rate, the charging current of the battery 18 decreases. As a result, a decrease in the negative electrode potential is suppressed, and precipitation of lithium metal is prevented.

  The processes in steps S240 to S285 described above are executed in the charge restriction processing unit 452 in FIG.

  Note that the same restriction as that in FIG. 5 is executed for the discharge current and Wout by the discharge restriction processing unit 454 in FIG. In this case, when the current IB increases in the (+) direction and exceeds the threshold value corresponding to Itag, Wout is limited. At this time, the waveform is obtained by vertically inverting the graph showing IB in FIG. 5 with the horizontal axis as the axis of symmetry. Further, the vertical axis of the graph showing Win in FIG. 5 may be read as Wout, and the positive and negative of the vertical axis may be replaced with (+) for the upward direction and (-) for the downward direction.

[Description of switching between required power distribution and charge / discharge power Pchg *]
In a hybrid vehicle that controls the SOC of the power storage device within a predetermined control range in the travel mode in which the engine operates, the engine outputs the sum of the power required for charging and discharging the power storage device and the power required for vehicle travel. Become. For this reason, normally, in order to control the SOC of the power storage device to the target SOC, discharge of the power storage device is promoted in the SOC region higher than the target SOC, while charging of the power storage device is performed in the SOC region lower than the target SOC. The engine output is controlled to facilitate.

  FIG. 7 is a flowchart for illustrating a control process for traveling control of the hybrid vehicle according to the present embodiment. The processing of each step in each flowchart including FIG. 7 is realized by software processing and / or hardware processing by the HV-ECU 302.

  In step S310, the HV-ECU 302 calculates the required drive torque Tr * from the vehicle state. For example, a map (not shown) in which the relationship between the accelerator opening (ACC) and the vehicle speed (V) and the required drive torque Tr * is determined in advance is stored in the HV-ECU 302 in advance. Then, the HV-ECU 302 can calculate the required drive torque Tr * by referring to the map based on the current accelerator opening and the vehicle speed. This process is executed by the required drive torque calculation unit 414 in FIG.

  Subsequently, HV-ECU 302 obtains charging / discharging power Pchg * of battery 18 in step S320. The charge / discharge power Pchg * is set to a positive value (Pchg *> 0) when a charge is requested, and is set to a negative value (Pchg * <0) when a discharge is requested. The method for setting the charge / discharge power Pchg * will be described in detail later. By determining the charge / discharge power Pchg *, the charge / discharge power of the battery 18 is set. In FIG. 2, the process of step S320 is executed by the SOC adjustment power calculation unit 460.

  Further, HV-ECU 302 calculates total required power Pt * in step S330. The total required power Pt * is calculated by the following equation (2). In Equation (2), Nr indicates the rotational speed of the output shaft 252 and Loss indicates a loss term.

Pt * = Tr * · Nr + Pchg * + Loss (2)
The processing in step S330 is executed by the required power calculation unit 440 and the addition unit 470 in FIG.

  In step S340, the HV-ECU 302 determines the operating point of the engine 20 according to the total required power Pt * calculated in step S330. At this time, the operating point is temporarily determined as total required power Pt * = engine required power Pe *.

FIG. 8 is a conceptual diagram for explaining the setting of the engine operating point.
Referring to FIG. 8, the engine operating point is defined by a combination of engine speed Ne and engine torque Te. The product of the engine speed Ne and the engine torque Te corresponds to the engine output power Pe.

  The operation line 110 is determined in advance as a set of engine operating points that can operate the engine 20 with high efficiency. The operation line 110 corresponds to an optimum fuel consumption line for suppressing fuel consumption at the same power output.

  In step S340, the HV-ECU 302 assumes that the predetermined operation line 110 and the total required power Pt * calculated in step S330 are the engine required power Pe *, and the equal power line corresponding to the engine required power Pe *. The intersection with 120 is determined as the engine operating point (target rotational speed Ne * and target torque Te *). The process of step S340 is executed by the engine operating point determination unit 484 in FIG.

  Referring to FIG. 7 again, HV-ECU 302 generates operation command values for engine 20 and motor generators 40, 60 in step S350.

  At this time, the output torque of the first MG 40 is determined such that the engine speed is controlled to the target speed Ne * by the output torque of the first MG 40 mechanically connected to the engine 20 by the power split mechanism 250.

  Further, HV-ECU 302 calculates drive torque (direct torque) Tep that is mechanically transmitted to output shaft 252 when engine 20 is operated in accordance with the engine operating point determined as described above. For example, direct torque Tep is set in consideration of the gear ratio of power split mechanism 250.

  Then, the HV-ECU 302 calculates the required drive torque Tmp * of the second MG 60 so as to compensate for the excess / deficiency (Tr * -Tep) of the direct torque Tep with respect to the required drive torque Tr *. That is, when the required drive torque to the second MG 60 is Tmp *, the following equation (3) is established. Note that Tmp * is the required drive torque of the torque that acts on the output shaft 252 by the output of the second MG 60.

Tr * = Tep + Tmp * (3)
If the electric power charged / discharged to the battery 18 when the first MG 40 and the second MG 60 are operated based on Tmp * thus calculated is within the range of Win and Wout, the command is output as it is. If the electric power charged / discharged to and from the range of Win and Wout appears, the command value is limited based on Win and Wout. At this time, the power required for the engine 20 may be increased or decreased by a limited amount. This processing is executed by the torque correction unit 486 in FIG.

  In step S500, the operation command values of engine 20, first MG 40, and second MG 60 are set based on the operating point of engine 20 and the output torque of first MG 40 and second MG 60 determined as described above. Engine 20 and first MG 40 and second MG 60 are controlled in accordance with these operation command values. At this time, the braking torque Tmb * is also taken into consideration.

  With such travel control, in the travel mode (HV mode) with engine operation, the engine 20, the required drive torque Tr * is applied to the drive shaft while the engine 20 is operated on a highly efficient operation line. The power distribution for the total required power between the first MG 40 and the second MG 60 can be determined. Further, the SOC can be controlled by charging / discharging the battery 18 according to the charge / discharge power Pchg *.

Next, the setting of the charge / discharge power Pchg * will be described in detail.
FIG. 9 is a flowchart for explaining details of a control process for setting the charge / discharge power Pchg *. The process of this flowchart shows the details of S320 of FIG. 7, and is called and executed when the process of step S310 of FIG. 7 is completed. According to the flowchart of FIG. 9, one of the three maps is selected and applied, and the charge / discharge power Pchg * is set.

  FIG. 10 is a standard map for determining the charge / discharge power Pchg *. FIG. 11 is a charge upper limit restriction map for determining the charge / discharge power Pchg *. FIG. 12 is a discharge upper limit restriction map for determining the charge / discharge power Pchg *.

  The standard map shown in FIG. 10 is set to Pchg * = 0 when the SOC is the target value SOCt. As the SOC increases from SOCt to SOCU, the charge / discharge power Pchg * increases from zero to P1 (discharge upper limit value). If the SOC is larger than the SOCU, Pchg * = P1 is set. Thereby, when the SOC is higher than the target value SOCt, the battery is discharged.

  Further, as the SOC decreases from SOCt to SOCL, the charge / discharge power Pchg * decreases from zero to P2 (charging upper limit value). If SOC is smaller than SOCL, Pchg * = P2. Thereby, when the SOC is lower than the target value SOCt, the battery is charged.

  Compared to the standard map of FIG. 10, in the charge upper limit restriction map of FIG. 11, the charge upper limit is restricted from P2 to P2X, and in the discharge upper limit restriction map of FIG. 12, the discharge upper limit is restricted from P1 to P1X. ing.

  Referring to FIG. 9, first, in step S321, it is determined whether or not a charge restriction process is being performed as a lithium battery protection process. In step S260 shown in FIG. 6, the HV-ECU 302 compares the battery current IB with the input current limit target value Itag to determine whether or not to execute the regeneration limit. The restriction intervention signal SIWin is turned on, and when the regeneration restriction is off, the restriction intervention signal SIWin is turned off.

  If the charging restriction process is in progress (SIWin = ON), the process proceeds to step S322. If the charging restriction process is not in progress (SIWin = OFF), the process proceeds to step S323.

  In step S322, the charge upper limit restriction map shown in FIG. 11 is applied to determine the charge / discharge power Pchg *. In the charge upper limit restriction map shown in FIG. 11, the charge upper limit is restricted from P2 to P2X compared to the standard map of FIG. Accordingly, by determining the charge / discharge power Pchg * by applying this map, the required charge power when the SOC is lower than the target value is large, so that the required charge power becomes small, so steps S280 and S285 in FIG. The frequency of execution of the Win restriction process by the Li precipitation suppression control shown in FIG. Therefore, the cumulative restriction on the previous value in step S285 is also reduced.

  On the other hand, in step S323, it is determined whether the discharge limiting process is being performed as the lithium battery protection process. The HV-ECU 302 compares the battery current IB with the output current limit target value (threshold value corresponding to Itag) in the discharge limit determination process similar to step S260 shown in FIG. However, when the discharge restriction is on, the restriction intervention signal SDWout is turned on. When the discharge restriction is off, the restriction intervention signal SDWout is turned off.

  If the discharge restriction process is in progress (SDWout = ON), the process proceeds to step S324. If the discharge restriction process is not in progress (SDWout = OFF), the process proceeds to step S325.

  In step S324, the discharge upper limit restriction map shown in FIG. 12 is applied to determine the charge / discharge power Pchg *. In the discharge upper limit restriction map shown in FIG. 12, the upper limit value of discharge is restricted from P1 to P1X compared to the standard map of FIG. Therefore, by applying this map to determine the charge / discharge power Pchg *, the required discharge power when the increase in the SOC is larger than the target value is large, so that the required discharge power becomes small. Therefore, steps S280 and S285 in FIG. The frequency at which the same process as the Li precipitation suppression control shown in (1) is applied to Wout is reduced, and the cumulative limitation of Wout is also reduced.

  On the other hand, in step S325, the standard map shown in FIG. 10 is applied to determine the charge / discharge power Pchg *. When the charge / discharge power Pchg * is determined by any one of steps S322, S324, and S325, the process proceeds to step S326, and the control returns to the flowchart of FIG.

FIG. 13 is a waveform diagram for explaining the restriction intervention signal SIWin.
In FIG. 13, the charging / discharging current IB of the battery 18 is shown in the upper stage, and the limiting intervention signal SIWin is shown in the lower stage. Until the time t11, the Li precipitation suppression threshold Itag is gradually narrowed (approaching zero) based on the charge / discharge history. A notice threshold value Tag2 that is offset by ΔImr2 in a direction close to zero with respect to the threshold value Itag is set. When the charging current reaches the warning threshold Itag, the restriction intervention signal SIWin changes from the off state to the on state. The limit intervention signal SIWin is kept on for a while once it is turned on. Accordingly, even if the charging / discharging current IB approaches zero immediately after the charging / discharging current IB reaches the warning threshold Itag2 at time t11, the time t11 to t12 is limited even if it moves away from the warning threshold Itag2. The intervention signal SIWin is kept on. For example, the HV-ECU 302 controls the generation of signals internally so that once the limited intervention signal SIWin changes to the on state, it does not return to the off state until a certain time has elapsed. In FIG. 2, the restriction intervention signal SIWin is generated as shown in FIG. 13 inside the charge restriction processing unit 452.

  If the SOC is significantly lower than the target value and the battery is being charged while the limiting intervention signal SIWin is in the on state, the charging upper limit value in FIG. 11 is limited from P2 to P2X. The charging current to the battery is also reduced. Therefore, the charge / discharge history of the battery 18 also changes in the direction in which the charge amount decreases, and thereby the threshold value Tag and the notice threshold value Tag2 change in a direction away from zero.

  Since such processing is performed, in the waveform diagram of FIG. 13, at time t11 to t12 and t13 to t14, the limiting intervention signal SIWin is turned on and the charging current is limited before the charging limiting processing unit 452 limits Win. Decrease.

  As described above, since the lithium battery protection process is suppressed, the power performance is improved and the fuel consumption is also improved.

  FIG. 14 is an operation waveform diagram for explaining the operation when the charge / discharge power Pchg * is not limited (comparative example) in the present embodiment.

  FIG. 15 is an operation waveform diagram for explaining the operation when the charge / discharge power Pchg * is limited in the present embodiment.

  In FIG. 14, the battery current IB reaches the threshold Itag that has been approaching zero based on the charge / discharge history of the battery 18 at time t21, and the battery protection process for suppressing lithium deposition is executed, and the input permitted power value. Win starts limiting toward zero.

  At time t21, since the SOC of the battery 18 is close to the lower limit side, the charge / discharge power Pchg * is set to a negative fixed value that requires charging. By continuing to set the charging / discharging power Pchg * to a negative fixed value, the charging current is eventually limited by the limitation of Win. In this case, since the state in which Win is limited continues, the degree of freedom of charge and discharge is impaired.

  On the other hand, in FIG. 15, the threshold Itag is approaching zero based on the charge / discharge history of the battery 18 at time t31. However, since the notice threshold value Tag2 is set, the battery current IB reaches the notice threshold value Tag2, and the charge / discharge power Pchg * is reduced to zero before the battery protection process for suppressing lithium deposition is executed. Start limiting towards.

  That is, when the charging current is about to reach the threshold Itag of the Li deposition suppression control (executed by the charge restriction processing unit 452 in FIG. 2), the charge / discharge power Pchg * for SOC adjustment is reduced. For this reason, the increase in SOC has a portion that rises more slowly than shown in FIG. 14, but Win is not limited as compared to FIG. Therefore, the effects of improved vehicle power performance and improved fuel efficiency can be obtained.

  The relationship described with reference to FIGS. 14 and 15 also holds for the relationship between the discharge current and the discharge limiting process executed by the discharge limiting processing unit 454 in FIG. 2 and Wout. Therefore, since the frequency at which Wout is restricted from the normal value is reduced, the effect of improving the vehicle power performance and improving the fuel consumption can be obtained in this respect as well.

[Modification]
In the above embodiment, as shown in FIGS. 11 and 12, whether or not the map limited to the standard map is applied to the calculation of the charge / discharge power Pchg * is determined in the charge limiting process or the discharge limiting process. Switching was performed based on the relationship between the notice threshold and the charge / discharge current.

  On the other hand, if the Li deposition suppression control intervenes, the forced charging power may be reduced and feedback control may be performed so that the intervention is eliminated.

  FIG. 16 is a diagram for explaining a map for determining charge / discharge power Pchg * in the modification. As shown in FIG. 16, the limit amount ΔP that further limits the charging upper limit value P2 may be changed little by little as P2X1, P2X2, and P2X3.

  FIG. 17 is a waveform diagram for explaining changes in Win and Pchg * in the modification.

  As shown in FIGS. 16 and 17, the limit amount ΔP for further limiting the charging upper limit value P2 is gradually changed to P2X1, P2X2, and P2X3 according to the degree of intervention (time, etc.) of the Li precipitation suppression control, and the Li precipitation suppression control is performed. Feedback control may be performed so as to eliminate the intervention.

  At time t41 in FIG. 17, the intervention of the Li precipitation suppression control is started based on the charge / discharge current history, and Win is starting to be limited. The amount of restriction of the charge / discharge power Pchg * for SOC adjustment is feedback controlled based on the degree of restriction of Win and the restriction duration. This increases the possibility that Win will return to the normal value before the Win limit increases.

  Finally, the present embodiment will be summarized with reference to the drawings again. Referring to FIGS. 1 and 2, the hybrid vehicle shown in the present embodiment can transmit rotational force between engine 20, battery 18 including a lithium ion secondary battery, and drive wheel 12. The motor generators 40 and 60 configured as described above are mounted. The control apparatus for the hybrid vehicle can request the first required power (charge / discharge power Pchg *) for bringing the state of charge of the battery 18 close to the target value (SOCt in FIG. 10) based on the state of charge of the battery 18 (see FIG. The total power Pt of the adjustment power calculation unit 460 calculated within 10 P1 to P2) and the second required power (Tr * × Nr) and the first required power (charge / discharge power Pchg *) required for traveling of the vehicle * And a distribution processing unit 480 for distributing power between the engine 20 and the motor generators 40 and 60 based on the input / output permission power values (Win, Wout) to the battery 18, and for protecting the battery 18 And a lithium battery protection processing unit 450 that performs protection processing. The lithium battery protection processing unit 450 changes the input / output permission power value (Win or Wout) based on the history of the charging / discharging current IB to the battery 18, and based on the history of the charging / discharging current IB to the battery 18. The adjustment power calculation unit 460 is instructed to change the first required power (charge / discharge power Pchg *).

  Preferably, when the charge / discharge current IB to the battery 18 is smaller than the threshold value | Itag |, the lithium battery protection processing unit 450 sets the input / output permission power value (Win or Wout) to the first standard value (Win0). Or if the charge / discharge current IB to the battery 18 is larger than the threshold value | Itag |, the input / output permission power value is limited as compared with the first standard value (Win0 or Wout0) as protection processing. To do. When the difference between the magnitude of the charging / discharging current IB to the battery 18 and the threshold value | Itag | becomes smaller than the predetermined value (ΔImr2 in FIG. 13), the lithium battery protection processing unit 450 adjusts the adjusted power calculation unit 460. Is requested to further limit the requestable range (P2 to P1 in FIG. 10) (P2X to P1 in FIG. 11 or P2 to P1X in FIG. 12).

  More preferably, the input / output permission power value includes an input permission power value Win indicating an upper limit value of charging power to the battery 18. When the magnitude of the charging current IB to the battery 18 is smaller than the charging threshold Itag, the lithium battery protection processing unit 450 sets the input permission power value Win to the first standard value Win0 and charges the battery 18 When the magnitude of the current IB is larger than the charging threshold value Itag, the charging limiting processing unit 452 that limits the input permission power value Win to the battery 18 from the first standard value is included as a protection process. When the difference between the magnitude of the charging current IB to the battery 18 and the charging threshold Itag becomes smaller than a predetermined value (ΔImr2 in FIG. 13), the charging restriction processing unit 452 requests the adjustment power calculation unit 460. An instruction is given to further limit charging upper limit value P2 in the possible range (P2 to P1 in FIG. 10) to P2X as shown in FIG.

  More preferably, the input / output permission power value includes an output permission power value Wout indicating an upper limit value of the discharge power of the battery 18. When the magnitude of the discharge current of the battery 18 is smaller than the discharge threshold value (threshold value corresponding to Itag in FIG. 5), the lithium battery protection processing unit 450 sets the output permission power value Wout to the first standard value Wout0. When the magnitude of the discharge current of the battery 18 is larger than the discharge threshold value (the threshold value on the discharge side corresponding to Itag in FIG. 5), the output permission power value Wout is set to the first standard as protection processing. A discharge restriction processing unit 454 that restricts the value Wout0 is included. The discharge restriction processing unit 454 is configured such that the difference between the magnitude of the discharge current of the battery 18 and the discharge threshold value (the threshold value on the discharge side corresponding to Itag in FIG. 5) is a predetermined value (the discharge side corresponding to ΔImr2 in FIG. Is less than the difference value), the adjustment power calculation unit 460 is instructed to further limit the discharge upper limit P1 of the required range (P2 to P1 in FIG. 10) to P1X as shown in FIG. To do.

  More preferably, the vehicle further includes a braking device 10 configured to apply a friction braking force to the drive wheels 12. The input / output permission power value includes an input permission power value Win indicating the upper limit value of the charging power to the battery 18 and an output permission power value Wout indicating the upper limit value of the discharge power of the battery 18. Distribution processing unit 480 distributes drive torque between engine 20 and motor generators 40 and 60 based on total power Pt *, input permitted power value Win, and output permitted power value Wout. Unit 483 and a braking torque distribution processing unit 482 that distributes the braking torque between motor generators 40 and 60 and braking device 10 based on required braking torque Trb * and input permission power value Win.

  Note that the vehicle in which the battery protection process and the SOC adjustment power calculation process according to the embodiment of the present invention are executed in cooperation is not limited to the hybrid vehicle 5 illustrated in FIG. The present invention includes a battery and a power generation device for charging the battery, and performs battery protection processing and charge / discharge power calculation processing for converging the SOC of the battery to a target value. Regardless of the number of electric motors (motor generators) to be mounted and the configuration of the drive system, the present invention can be commonly applied to all electric vehicles including fuel cell vehicles and the like that are not equipped with an engine in addition to hybrid vehicles. In particular, the configuration of the hybrid vehicle is not limited to the example shown in FIG. 1, and the present invention can be applied to any configuration including a parallel hybrid vehicle.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  DESCRIPTION OF SYMBOLS 5 Hybrid vehicle, 10 Braking device, 12 Drive wheel, 14 Reduction gear, 18 Battery, 19 Battery sensor, 20 Engine, 22 Brake pedal, 34 Accelerator pedal operation amount detection part, 36 Switch, 40 1st MG, 40, 60 Motor generator , 41, 42 Rotational position sensor, 60 2nd MG, 80 Brake hydraulic pressure circuit, 82 Hydraulic pressure sensor, 84 Brake pedal operation amount detector, 100, 250 Power split mechanism, 102 First ring gear, 102a Ring gear shaft, 104 1st Pinion gear, 106 1st carrier, 108 1st sun gear, 110 operation line, 120 equal power line, 160 brake caliper, 161 vehicle speed sensor, 162 brake disc, 164 drive shaft, 200 transmission, 202 second phosphorus Gear, 204 second pinion gear, 206 second carrier, 208 second sun gear, 252 output shaft, 300 brake ECU, 304 engine ECU, 306 power supply ECU, 310 communication bus, 410 required torque calculation unit, 412 required braking torque calculation unit, 414 Required drive torque calculator, 420 SOC estimator, 430 Win / Wout standard value calculator, 440 Required power calculator, 450 Lithium battery protection processor, 452 Charge limit processor, 454 Discharge limit processor, 460 SOC adjustment power Calculation unit, 470 addition unit, 480 distribution processing unit, 482 braking torque distribution processing unit, 483 drive torque distribution processing unit, 484 engine operating point determination unit, 486 torque correction unit, 488 motor torque addition unit.

Claims (6)

A control device for a hybrid vehicle including an engine, a battery including a lithium ion secondary battery, and a motor generator configured to be able to transmit rotational force between wheels,
An adjustment power calculation unit that calculates a first required power within a requestable range for bringing the state of charge of the battery closer to a target value based on the state of charge of the battery;
Distribution for performing power distribution between the engine and the motor generator based on the total power of the second required power and the first required power required for traveling of the vehicle and the input / output permission power value to the battery A processing unit;
A battery protection processing unit for performing a protection process for protecting the battery,
The battery protection processing unit changes the input / output permission power value based on a history of charge / discharge current to the battery, and to the adjusted power calculation unit based on a history of charge / discharge current to the battery. A control device for a hybrid vehicle that instructs to change the first required power. The battery protection processing unit
When the magnitude of the charge / discharge current to the battery is smaller than the threshold value, the input / output permission power value is set to a first standard value, and the magnitude of the charge / discharge current to the battery is larger than the threshold value. In the case, the input / output permission power value is limited as the protection process from the first standard value,
The battery protection processing unit
When the difference between the charge / discharge current to the battery and the threshold value is smaller than a predetermined value, the adjustment power calculation unit is instructed to further limit the requestable range. Item 2. The hybrid vehicle control device according to Item 1. The input / output permission power value includes an input permission power value indicating an upper limit value of charging power to the battery,
The battery protection processing unit
When the magnitude of the charging current to the battery is smaller than the charging threshold, the input allowed power value is set to the first standard value, and the magnitude of the charging current to the battery is the charging threshold. In the case of being larger, a charge restriction processing unit for restricting the input permission power value to the battery as the protection process from the first standard value,
The charging restriction processing unit
When the difference between the magnitude of the charging current to the battery and the charging threshold value is smaller than the predetermined value, the adjustment power calculation unit is further limited to the charging upper limit value of the requestable range. The hybrid vehicle control device according to claim 2, wherein an instruction is given. The input / output permission power value includes an output permission power value indicating an upper limit value of the discharge power of the battery,
The battery protection processing unit
When the magnitude of the discharge current of the battery is smaller than the discharge threshold value, the output permission power value is set to the first standard value, and the magnitude of the battery discharge current is larger than the discharge threshold value. In the case, including a discharge restriction processing unit for restricting the output permission power value from the first standard value as the protection process,
The discharge restriction processing unit
When the difference between the discharge current magnitude of the battery and the discharge threshold value is smaller than the predetermined value, the adjustment power calculation unit is instructed to further limit the discharge upper limit value of the requestable range. The control apparatus of the hybrid vehicle of Claim 2 which performs. The vehicle further includes a braking device configured to apply a friction braking force to the wheels,
The input / output permission power value includes an input permission power value indicating an upper limit value of charging power to the battery, and an output permission power value indicating an upper limit value of discharge power of the battery,
The distribution processing unit
A drive torque distribution processing unit that distributes drive torque between the engine and the motor generator based on the total power, the input permitted power value, and the output permitted power value;
The hybrid vehicle control according to claim 2, further comprising: a braking torque distribution processing unit that distributes a braking torque between the motor generator and the braking device based on a required braking torque and the input permission power value. apparatus.   A hybrid vehicle comprising the control device according to claim 1.

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