JP2012182935A - Control device of vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent drivability of a vehicle from degrading because of instantaneous fluctuation of a vehicle braking force, with a recovery energy of regenerative power generation being assured, while control to suppress Li precipitation is performed, relating to a vehicle on which a lithium ion secondary battery is mounted.SOLUTION: An HV-ECU302 adjusts the upper limit value of charge power based on charging/discharging history of a battery 18, to suppress Li precipitation in the battery 18 which is a lithium ion secondary battery. Further, the HV-ECU302 performs braking coordination control which determines assignment of hydraulic braking force by a control device 10 and regenerative braking force by a second MG60, in response to a requested braking force corresponding to the operation of a brake pedal within the range of upper limit value of charge power that is adjusted. The limitation degree of a charge power upper limit value when limiting the charge power upper limit value for suppressing Li precipitation is reduced according to increase in accumulated operation frequency of a liquid pressure control actuator at a brake liquid pressure circuit 80 for supplying liquid pressure to the control device 10.

Description

  The present invention relates to a vehicle control device, and more particularly to brake coordination control using a regenerative braking force and a hydraulic braking force.

  In an electric vehicle such as a hybrid vehicle or an electric vehicle equipped with a vehicle driving motor, a regenerative braking force by the vehicle driving motor and a braking force by a hydraulic braking device (hereinafter also referred to as a hydraulic braking force) are coordinated during braking. Thus, braking force control for ensuring the required braking force of the entire vehicle has been put into practical use (for example, Patent Documents 1 to 3). Hereinafter, such braking force control is also referred to as “brake cooperative control”. By collecting the power generated by the regenerative braking as the charging power of the on-vehicle power storage device, the energy efficiency of the vehicle, that is, the fuel efficiency, is improved.

  Japanese Patent Laid-Open No. 2010-104087 (Patent Document 1) discloses a regenerative torque of an electric motor, that is, a regenerative braking force, based on the number of times of braking per predetermined travel distance in brake cooperative control of regenerative braking and friction braking by hydraulic pressure. It is described to increase.

  Japanese Patent Laid-Open No. 2010-104086 (Patent Document 2) describes an elapsed time in a state where the deceleration is equal to or higher than a predetermined value and the vehicle speed is equal to or higher than a predetermined value in the brake cooperative control during deceleration of the vehicle. Based on this, control for increasing the amount of regenerative torque of the electric motor is described.

  Japanese Patent Laid-Open No. 2010-141997 (Patent Document 3) discloses a reference for a charging power upper limit value that limits a regenerative braking force in accordance with a change speed of a charging power upper limit value of a power storage device in brake cooperative control of an electric vehicle. It describes that the value is set to be variable. As a result, it is possible to secure the time required for increasing the hydraulic pressure when shifting from a state where both regenerative braking and hydraulic braking are used to a state where only hydraulic pressure control is used.

  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, it is known that lithium ion secondary batteries may cause battery heat generation or performance degradation due to deposition of lithium metal on the negative electrode surface depending on the usage. For this reason, International Publication No. 2010/005079 (Patent Document 4) adjusts the input permission power to the battery based on the charge / discharge history in order to suppress the deposition of lithium metal at the negative electrode of the lithium ion secondary battery. Control to do is described. Specifically, based on the battery current history, the maximum current value at which lithium metal does not precipitate is sequentially calculated, and the input permission power to the battery is adjusted so that the battery current does not exceed the maximum current value. Is described.

JP 2010-104087 A JP 2010-104086 A JP 2010-141997 International Publication No. 2010/005079

  In a vehicle that performs brake cooperative control as described in Patent Documents 1 to 3, the fuel efficiency can be improved as the ratio of the regenerative braking force is increased during deceleration. Therefore, in a vehicle using a lithium ion secondary battery as an in-vehicle power storage device, it is preferable to increase the share of regenerative braking as much as possible after suppressing lithium metal deposition.

  However, as shown in Patent Document 4, when the charging state is such that lithium metal is likely to be deposited, it is necessary to limit the charging power to the battery, and thus the regenerative braking force is also limited. . When such charge restriction is started, it is necessary to reduce the regenerative braking force in order to suppress lithium metal deposition by brake cooperative control, while replacing the reduced amount with the hydraulic braking force.

  At this time, if the regenerative braking force is changed at a high rate, as described in Patent Documents 1 to 3, there is a possibility that instantaneous fluctuations may occur in the vehicle braking force due to the response delay of the hydraulic braking force. is there. When such a variation in braking force occurs, there is a possibility that the vehicle user may feel uncomfortable even if the braking performance of the vehicle is not affected. Therefore, it is a challenge to improve both energy efficiency by securing regenerative power and to suppress instantaneous braking force fluctuations.

  The present invention has been made to solve such a problem, and the object of the present invention is to limit charging in a vehicle equipped with a lithium ion secondary battery so as to suppress lithium metal deposition. In other words, the brake cooperative control is performed so that the instantaneous fluctuation of the vehicle braking force due to the influence of the control does not occur while securing the recovered energy by the regenerative power generation.

  In one aspect of the present invention, there is provided a control device for a vehicle, wherein the vehicle is configured such that a battery including a lithium ion secondary battery and a braking force corresponding to a supplied hydraulic pressure are applied to the wheels. To perform bidirectional power conversion between the battery generator and the motor generator so as to control the output torque of the motor generator and the motor generator configured to be able to mutually transmit the rotational force between the device and the wheel Power controller. The control device includes a charge control means for adjusting the charge power upper limit value of the battery so as to prevent the negative electrode potential of the battery from being lowered to the lithium reference potential based on the charge / discharge history of the battery, and the adjusted charge Braking control for determining the sharing of the hydraulic braking force and the regenerative braking force by the braking device with respect to the required braking force corresponding to the brake pedal operation so that the motor generator generates the regenerative braking force within the range of the power upper limit value Means and a counting means for counting the cumulative number of operations of the actuator for controlling the hydraulic pressure supplied to the braking device. The charging control means is a setting means for reducing the limit degree of the charging power upper limit value when limiting the charging power upper limit value in order to prevent a decrease in the negative electrode potential according to the cumulative number of operations detected by the counting means. including.

  Preferably, when the cumulative number of operations exceeds a predetermined threshold, the setting means sets a limit rate indicating a time change rate when the charge power upper limit value is decreased, compared to a case where the cumulative number of operations is less than the threshold. Set to a lower value. The charge control means sequentially sets the input allowable current value as the maximum current at which lithium metal does not deposit on the negative electrode of the battery based on the charge / discharge history, and reduces the input allowable current value as the limit rate increases. Means for determining an input current limit target value so as to have a set margin, and means for decreasing the charging power upper limit value according to the limit rate when the charging current of the battery exceeds the input current limit target value And further including.

  More preferably, the actuator is a solenoid valve configured to be opened and closed when the hydraulic pressure is changed.

  Preferably, the condition for starting the limit of the charging power upper limit value is relaxed as the limit degree is higher.

  According to the present invention, in a vehicle equipped with a lithium ion secondary battery, after executing control to limit charging so as to suppress the deposition of lithium metal, while ensuring the recovered energy by regenerative power generation, Brake coordination control can be performed so as not to give the user a sense of incongruity due to instantaneous fluctuations in the vehicle braking force due to the influence.

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 block diagram which shows the specific structural example of the brake hydraulic pressure circuit shown in FIG. FIG. 3 is a schematic structural diagram of the linear solenoid valve shown in FIG. 2. It is a conceptual diagram explaining the example of the brake cooperation control by regenerative braking force and hydraulic braking force. 2 is a flowchart showing a control processing procedure of brake cooperative control in the hybrid vehicle shown in FIG. 1. It is a wave form diagram explaining Li precipitation suppression control performed with the hybrid vehicle by embodiment of this invention. It is a wave form diagram explaining the regeneration restriction | limiting by Li precipitation suppression control. It is a conceptual waveform diagram explaining the response delay of the hydraulic pressure control in the brake hydraulic pressure circuit. It is a functional block diagram explaining the brake cooperation control combined with Li precipitation suppression control in the vehicle by an embodiment of the invention. It is a notional operation waveform diagram for explaining the definition of the number of operations of the linear solenoid valve. 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 explaining the process which sets a regeneration limiting rate according to the frequency | count of accumulation operation | movement of an actuator (linear solenoid valve). It is a conceptual waveform diagram explaining the relationship between the cumulative number of operations of the actuator (linear solenoid valve) and the set value of the regeneration limit rate in the embodiment of the present invention.

  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 the description thereof will not be repeated in principle.

  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 a braking device 10, drive wheels 12, a reduction gear 14, an engine 20, and a first motor generator for power generation and engine start (hereinafter referred to as a first MG). 40, a second motor generator (hereinafter referred to as second MG) 60 for driving the vehicle, a brake hydraulic circuit 80, a power split mechanism 100, and a transmission 200.

  The hybrid vehicle 5 includes a power control unit 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, an engine ECU 304, and a power supply ECU 306. And further including. Typically, each ECU includes a microcomputer (not shown) including a CPU (Central Processing Unit), a memory, an input / output port, and a communication port. 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.

  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.

  In the present embodiment, brake ECU 300, HV-ECU 302, engine ECU 304, and power supply ECU 306 have been described as separate ECUs, but some or all of these ECUs are integrated. An ECU may be provided.

  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. The engine 20 is provided with an engine speed sensor 34. The engine speed sensor 34 detects the speed of the engine 20 and transmits a signal indicating the detected speed of the engine 20 to the engine ECU 304.

  The engine ECU 304 controls the fuel injection amount, ignition timing, intake air amount, and the like of the engine 20 based on signals from various sensors including the engine speed sensor 34. Thereby, engine 20 is controlled so as to operate at the target rotational speed and target torque determined by HV-ECU 302.

  The battery 18 is constituted by a lithium ion secondary battery. A lithium ion secondary battery has a high energy density, and an initial circuit voltage and an average operating voltage are higher than those of other secondary batteries. For this reason, the lithium ion secondary battery is suitable for an in-vehicle power storage device for a vehicle that requires a large battery capacity and a 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 4, 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 4, 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 deposition 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 is a positive value (Ib> 0) when the battery 18 is discharged and a negative value (Ib <0) when charging. 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 61 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 165 is provided on the drive shaft 164. Based on the rotational speed of the drive shaft 164 detected by the vehicle speed sensor 165, 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 from that state and torque is output in the forward rotation direction, 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. Thereby, the second MG 60 operates as a generator. As a result, the second MG 60 acts as a regenerative brake that 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 starting the vehicle and traveling at a low speed, the hybrid vehicle 5 travels by the output of the second MG 60 with the engine 20 stopped. During steady running, the engine 20 is started, and the hybrid vehicle 5 runs by 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, HV-ECU 302 reflects the amount of operation of an accelerator pedal (not shown), sets the required driving force for the entire vehicle, and implements engine 20, first MG 40 and first MG so as to realize the travel control. An operation command value (typically, a rotation speed command value and / or a torque command value) of 2MG60 is set.

  Further, the HV-ECU 302 estimates the SOC (State of Charge) of the battery 18 based on the state values (battery current Ib, battery voltage Vb, battery temperature Tb) detected by the battery sensor 19. 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 (not shown in FIG. 1) 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. That is, the braking device 10 corresponds to a “braking device”.

  The brake fluid pressure circuit 80 is controlled in accordance with an operation command from the brake ECU 300 to control the supply fluid pressure Pwc to the braking device 10.

  FIG. 2 is a block diagram showing a specific configuration example of the brake hydraulic circuit 80 shown in FIG.

  Referring to FIG. 2, brake hydraulic pressure circuit 80 includes a hydraulic booster 81, a pump motor 82, an accumulator 83, a reservoir 84, a hydraulic pressure control circuit 85, and a stroke simulator 89.

  The hydraulic pressure control circuit 85 includes switching rhenoid valves SSC, SMC, SRC, SCC, linear solenoid valves SLA, SLR for controlling wheel cylinder hydraulic pressure during normal braking, and control solenoid valves FLH, FLR, FRH, FRR, RLH. , RLR, RRH, RRR and hydraulic pressure sensors 86-88. The operation of each solenoid valve is controlled in response to a control signal Svl from the brake ECU 300.

  The hydraulic booster 81 is configured to generate a hydraulic pressure (regulator pressure Prg) corresponding to the pedaling force so as to amplify the pedaling force of the brake pedal 22. The regulator pressure Prg from the hydraulic pressure booster 81 can be detected by a hydraulic pressure sensor 87. The value detected by the hydraulic pressure sensor 87 is sent to the brake ECU 300.

  The brake ECU 300 can detect the operation amount (stepping force) of the brake pedal 22 based on the detected regulator pressure Prg. Alternatively, by providing a stroke sensor that directly detects the operation amount of the brake pedal 22, the operation amount (depression force) of the brake pedal 22 can be detected.

  The stroke simulator 89 is configured to apply a reaction force according to the operation of the brake pedal 22 to the brake pedal 22 so as to give an optimal brake feeling to the driver.

  The pump motor 82 increases the pressure of the working fluid accumulated in the reservoir 84. The working fluid output from the pump motor 82 is supplied to the hydraulic pressure control circuit 85 via the accumulator 83. This supply hydraulic pressure (accumulator pressure Pac) can be detected by a hydraulic pressure sensor 88. The detected value of the accumulator pressure Pac by the hydraulic pressure sensor 88 is sent to the brake ECU 300. The brake ECU controls the pump motor 82 so that the accumulator pressure matches the command value.

  The switching solenoid valve SSC opens and closes a path leading to the stroke simulator 89. The switching solenoid valve SCC opens and closes a path between the fluid path 90 on the rear wheel side and the fluid path 91 on the front wheel side. The switching solenoid valve SMC opens and closes the path from the hydraulic pressure booster 81 to the fluid path 90. The switching solenoid valve SRC opens and closes the path from the hydraulic pressure booster 81 to the fluid path 91. The switching solenoid valves SMC, SRC are normally closed, and the switching solenoid valve SRC is normally open.

  The linear solenoid valves SLA and SLR control the fluid pressure (wheel cylinder pressure Pwc) of the fluid passages 90 and 91 detected by the fluid pressure sensor 86. The detected value of the wheel cylinder pressure Pwc by the hydraulic pressure sensor 86 is sent to the brake ECU 300.

  The brake ECU 300 controls the opening degrees of the linear solenoid valves SLA and SLR so that the wheel cylinder pressure Pwc matches the target hydraulic pressure. When increasing the wheel cylinder pressure, the linear solenoid valve SLA is opened (opening> 0) while the linear solenoid valve SLR is closed (opening = 0). On the other hand, when the wheel cylinder pressure is reduced, the linear solenoid valve SLR is opened while the linear solenoid valve SLA is closed. That is, the linear solenoid valves SLA and SLR correspond to “actuators” for controlling the hydraulic pressure (wheel cylinder pressure) supplied to the braking device 10.

  Control solenoid valves FLH, FLR, FRH, FRR, RLH, RLR, RRH, and RRR independently control the hydraulic pressure supplied to the wheel cylinder 161 of each wheel during the operation of ABS (Anti-lock Brake System), traction control system, etc. It is provided to control. The control solenoid valve includes a holding valve FLH, FRH, RLH, RRH for holding the supply hydraulic pressure to the corresponding wheel cylinder 161, and a pressure reducing valve FLR, for reducing the supply hydraulic pressure to the corresponding wheel cylinder 161. Includes FRR, RLR, and RRR. When the ABS or the like is not in operation, each control solenoid valve is kept closed.

  During normal braking, the wheel cylinder pressure Pwc controlled by the linear solenoid valves SLA and SLR is commonly supplied to the wheel cylinders 161. That is, the wheel cylinder pressure Pwc detected by the hydraulic pressure sensor 86 corresponds to the supply hydraulic pressure Pwc to the braking device 10 shown in FIG.

  When the hydraulic pressure control circuit 85 is abnormal, the switching solenoid valves SMC and SRC are opened, so that hydraulic pressure (regulator pressure) corresponding to the brake depression force is supplied from the hydraulic pressure booster 81 to each wheel cylinder 161. Is done. Further, by closing the switching solenoid valve SCC according to the abnormal part, the front wheel side path and the rear wheel side path can be separated.

  FIG. 3 is a schematic structural diagram of the linear solenoid valve shown in FIG. FIG. 3 typically shows the structure of the linear solenoid valve SLA.

  Referring to FIG. 3, linear solenoid valve SLA includes a solenoid core 501, a plunger 502, and a biasing means 505.

  The solenoid core 501 is supplied with a current from a power source (not shown) in response to a control signal instructing the opening degree of the linear solenoid valve. The solenoid core 501 causes the electromagnetic force Fe corresponding to the supplied current amount to act on the plunger. The opening degree can be controlled by changing the current amount of the solenoid core 501 according to the instruction of the opening degree.

  The urging means 505 is configured by a spring or the like, and applies an urging force Fs to the plunger 502. The urging force Fs acts in the opposite direction to the electromagnetic force Fe by the solenoid core 501.

  When the solenoid core 501 is not energized, the electromagnetic force Fe = 0. Therefore, the plunger 502 closes the contact 506 by the urging force Fs. When the contact 506 is in the closed state, the path of the working fluid from the accumulator side to the wheel cylinder side is interrupted. In order to provide reliable interruption, the contact 506 is provided with a mechanical seal structure made of a coating material or the like.

  On the other hand, when the solenoid core 501 is energized, the electromagnetic force Fe that overcomes the urging force Fs acts, so that the plunger 502 opens the contact 506. When the contact 506 is in an open state, a working fluid path is formed from the accumulator side to the wheel cylinder side, thereby increasing the wheel cylinder pressure.

  The linear solenoid valve SLR has the same structure as the linear solenoid valve SLA shown in FIG. In the linear solenoid valve SLR, when the wheel cylinder pressure is decreased, a current is supplied to the solenoid core 501 and the contact 506 is opened.

  As the contact 506 is opened and closed for hydraulic pressure control, the plunger 502 collides with the wall. Therefore, if the number of collisions becomes excessive, the sealing function may be deteriorated due to dropping of the coating material or wear of the plunger 502 or the wall portion. For example, the seal structure is designed to have a strength that does not deteriorate due to the cumulative number of operations of the linear solenoid valve in a certain service life, which is assumed in a normal use state. However, if the cumulative number of operations of the linear solenoid valve becomes excessive beyond the design assumption due to frequent use of the brake, the sealing function at the contact 506 may be deteriorated. In this case, since the working fluid cannot be properly blocked by the plunger 502, the responsiveness when controlling the hydraulic pressure may be reduced.

  In the hybrid vehicle 5 shown in FIG. 1, the required braking force (total braking force) for the entire vehicle corresponding to the operation of the brake pedal 22 by the driver is expressed as the regenerative braking force by the second MG 60 and the hydraulic braking force by the braking device 10. Brake coordination control is performed in which the output is shared and output. FIG. 4 shows an example of brake cooperative control by hydraulic braking and regenerative braking.

  Referring to FIG. 4, W10 represents the total braking force based on the driver's brake pedal operation. On the other hand, W20 indicates the regenerative braking force generated by the second MG 60. It is understood that the total braking force is ensured by the sum of the regenerative braking force and the hydraulic braking force. 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 to a range in which the input power to the battery 18 does not exceed Win (that is, within a range where Pb> Win). Therefore, if Win is limited, the original regenerative braking force shown in FIG. 4 may not be ensured. In particular, when the Li precipitation suppression control shown in Patent Document 4 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.

  At this time, it is necessary to increase the hydraulic braking force in correspondence with the decrease in the regenerative braking force. However, as described in Patent Document 1 and the like, in the case where the regenerative braking force suddenly decreases, the increase in the hydraulic braking force (an increase in the hydraulic pressure) cannot follow, and the target total There is a possibility that the braking force cannot be secured instantaneously. Then, even if the braking performance of the vehicle is not affected, there is a possibility that the vehicle user may feel uncomfortable.

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

  FIG. 5 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. 5 is executed by the HV-ECU 302 at regular intervals. Further, each step shown in FIG. 5 is realized by software processing and / or hardware processing by the HV-ECU 302.

  Referring to FIG. 5, 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, for example, the regulator pressure Prg detected by the hydraulic pressure sensor 87 in FIG. The vehicle speed V is detected based on the output of the vehicle speed sensor 165. The rotational speeds Nm1 and Nm2 can be calculated based on the outputs of the rotational position sensors 41 and 61 attached to the first MG 40 and the second MG 60.

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

  Typically, the required braking torque Tr * is calculated as a 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 Tr * is predetermined can be created in advance and stored in a memory (not shown) in the HV-ECU 302. In step S110, the required braking torque Tr * 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 to be shared among the required braking torque Tr * in accordance with 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 that the battery power (Pb = Vb · Ib) does not exceed 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 |.

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

Tbk * = Tr * −Tm2 * · Gr (1)
In this way, the brake cooperative control in which the required braking torque Tr * is shared by the regenerative braking torque (Tm2 *) and the hydraulic brake torque (Tbk *) is realized. That is, the function of “braking control means” is realized by the processing of steps S100 to S140.

  Further, in step S150, HV-ECU 302 outputs hydraulic brake torque Tbk * set in step S140 to brake ECU 300 (FIG. 1).

  The brake ECU 300 calculates a target hydraulic pressure to be supplied to the braking device 10 based on the hydraulic brake torque Tbk *. Then, the hydraulic pressure control circuit 85 shown in FIG. 2 is controlled so that the wheel cylinder pressure (Pwc) detected by the hydraulic pressure sensor 86 matches the target hydraulic pressure.

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

  6 and 7 are waveform diagrams illustrating the Li precipitation suppression control executed in hybrid vehicle 5 according to the embodiment of the present invention.

  Referring to FIG. 6, 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 4, 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 4. 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 4, 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. 6, 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. When Ib becomes lower than Itag at time t1 (Ib <Itag), it is necessary to limit the charging current in order to suppress lithium metal deposition.

  For this reason, as shown in FIG. 7, 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. 6 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. 7, 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 FIGS. 6 and 7, the larger the margin current ΔImr is, the more severe the start condition for the regeneration restriction. 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 restriction during regenerative braking, the processing of steps S120 and S130 of FIG. 5 reduces the share of regenerative braking torque (the absolute value of MG2 torque), and in response to the decrease, The share of the pressure brake torque Tbk * 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. As described above, at this time, a certain delay occurs in the increase in the supply hydraulic pressure Pwc with respect to the increase in the command value. Thereby, since the hydraulic brake torque is momentarily insufficient, there is a possibility that momentary fluctuations in the vehicle braking force may occur, giving the user a sense of discomfort.

  FIG. 8 is a conceptual waveform diagram for explaining the response delay of the hydraulic pressure control in the brake hydraulic pressure circuit.

  Referring to FIG. 8, when the supply hydraulic pressure to brake device 10 is increased, the wheel cylinder pressure command value is increased. Then, the brake ECU 300 controls the linear solenoid valve SLA shown in FIG. 2 so that the wheel cylinder pressure Pwc matches the increased command value. As a result, the actual value of the wheel cylinder pressure Pwc (that is, the hydraulic pressure supplied to the braking device 10) increases following the command value.

  At this time, a certain required time (delay time) ΔT exists for the wheel cylinder pressure Pwc to rise to the command value. A hydraulic pressure response rate is obtained by dividing the hydraulic pressure change amount ΔP by the delay time ΔT. It is understood that the rate (time change rate) at which the hydraulic brake torque is increased without causing an instantaneous fluctuation of the vehicle braking force when the regeneration is limited is determined depending on the hydraulic response rate. .

  As described above, when the accumulated value of the number of operations (opening / closing times) of the linear solenoid valves SLA and SLR which are actuators for controlling the hydraulic pressure (wheel cylinder pressure) supplied to the braking device 10 becomes excessive, the contact 506 (FIG. There is a possibility that the hydraulic pressure response rate may decrease due to the deterioration of the sealing performance in 3) over time. In such a case, there is a possibility that the vehicle braking force may fluctuate instantaneously due to the increase in the hydraulic brake torque being delayed from the expected time.

  For this reason, it is conceivable to set the regenerative restriction rate uniformly low so as to have a sufficient margin against a decrease in hydraulic pressure control responsiveness due to deterioration over time. However, when the regeneration limiting rate is lowered, the charging current starting from Ib <Itag also becomes moderate. Therefore, in order to prevent lithium metal from precipitating, it is necessary to increase the margin current ΔImr shown in FIG. 6 from the viewpoint of surely preventing Ib from reaching Ilim. That is, if the charge power limit for regeneration limitation is lowered, it is necessary to tighten the conditions for starting regeneration limitation. As a result, the recovered energy by regenerative power generation is reduced by excessively limiting Win.

  Therefore, in the embodiment of the present invention, as will be described below, the regeneration limit rate of the Li precipitation suppression control is variably set based on the cumulative number of operations of the actuator (rear solenoid valve) in the brake hydraulic circuit 80. .

  FIG. 9 is a functional block diagram illustrating brake cooperative control combined with Li precipitation suppression control in the vehicle according to the embodiment of the present invention. Each functional block shown in FIG. 9 can be realized by software processing and / or hardware processing by the brake ECU 300 or the HV-ECU 302.

  Referring to FIG. 9, brake ECU 300 includes a hydraulic pressure control unit 315 and an actuator operation frequency counting unit 320. The HV-ECU 302 includes a regeneration limit rate setting unit 330, an SOC calculation unit 340, a current determination unit 350, and a Win setting unit 360. FIG. 9 shows functional blocks of a portion related to the “charge control means” related to the Li precipitation suppression control among the functions of the HV-ECU 302.

  The hydraulic pressure control unit 315 generates a wheel cylinder pressure command value Pwc * based on the hydraulic brake torque Tbk * set by the HV-ECU 302 according to the flowchart of FIG. Further, the hydraulic pressure control unit 315 performs the hydraulic pressure control circuit 85 (particularly a linear solenoid) shown in FIG. 2 based on the command value Pwc * and the actual value of the wheel cylinder pressure Pwc detected by the hydraulic pressure sensor 86. A control signal Svl for controlling the valves SLA, SLR) is generated. The control signal Svl is sent to the brake hydraulic circuit 80.

  The actuator operation frequency counting unit 320 counts the operation times of the hydraulic pressure control actuators (linear solenoid valves SLA and SLR in the example of FIG. 2) in the brake hydraulic pressure circuit 80. Thereby, the cumulative number of operations of the linear solenoid valve (actuator) is obtained. The number of operations can be counted based on a control signal (part of Slv) instructing opening / closing of the linear solenoid valves SLA, SLR or a performance signal indicating an operation state of the linear solenoid valves SLA, SLR. That is, the actuator operation frequency counting unit 320 corresponds to “counting means”.

  FIG. 10 is a conceptual operation waveform diagram for explaining the definition of the number of operations of the linear solenoid valve.

  In FIG. 10, in order to simplify the explanation, a waveform is shown when the regeneration limitation by the Li precipitation suppression control is executed a plurality of times while the required braking torque Tr * according to the operation of the brake pedal is constant. ing.

  Referring to FIG. 10, regeneration restriction is turned on at each of times t1, t3, and t4. Each time the regenerative restriction is turned on, it is necessary to increase the hydraulic braking torque while reducing the regenerative braking torque. That is, the linear solenoid valve operates and the wheel cylinder pressure Pwc increases. At this time, the linear solenoid valve SLA is opened from the closed state to increase the pressure. When the pressure increases to the command value, the linear solenoid valve SLA returns to the closed state again. This series of opening / closing operations causes a mechanical collision at the contact 506 described with reference to FIG.

  Therefore, each time the linear solenoid valve is opened from the closed state (opening degree = 0) (that is, opening degree> 0), the number of operations of the linear solenoid valve can be counted by increasing the number of operations by one.

  Referring again to FIG. 9, the cumulative operation number Csv detected by actuator operation number counting unit 320 is sent to regeneration limit rate setting unit 330. When there are a plurality of linear solenoid valves (SLA, SLR in FIG. 2), the linear solenoid valve having the largest number of operations or a specific linear solenoid designated in advance because of its influence on hydraulic pressure control. The number of valve operations can be set to the cumulative operation number Csv.

  The SOC calculation unit 340 calculates an estimated value of the SOC of the battery 18 based on the state values (battery current Ib, battery voltage Vb, battery temperature Tb) detected by the battery sensor 19. Hereinafter, the estimated SOC value is also simply expressed as “SOC”.

  Based on the state value of battery 18 and the SOC, current determination unit 350 determines whether or not it is in a state that requires regeneration limitation by Li deposition suppression control. As will be described later in detail, this determination reflects the history of the battery current Ib. The current determination unit 350 turns on the flag FLG when regeneration limitation by the Li precipitation suppression control is necessary, and turns off the flag FLG when it is not. The flag FLG is sent to the Win setting unit 360.

  The regenerative restriction rate setting unit 330 sets the regenerative restriction rate Pr so that the regenerative restriction rate Pr decreases as the cumulative operation count Csv of the actuator increases. In other words, the regeneration limit rate setting unit 330 corresponds to “setting means”.

  Based on the current battery state (SOC, state value), the flag FLG from the current determination unit 350, and the regeneration limit rate Pr set by the regeneration limit rate setting unit 330, the Win setting unit 360 Set Win.

  FIG. 11 is a flowchart showing a control process for realizing the Li precipitation suppression control shown in FIG. FIG. 12 shows a flowchart for explaining in detail the control processing in step S250 of FIG.

  The control process according to the flowchart shown in FIG. 11 is executed by the HV-ECU 302 at regular intervals. Each step shown in FIGS. 11 and 12 can be realized by software processing and / or hardware processing by the HV-ECU 302.

  Referring to FIG. 11, 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. That is, the process of S210 corresponds to the function of the SOC calculation unit 340 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 the SOC and the battery temperature Tb.

  In step S240, the HV-ECU 302 inputs the cumulative operation frequency Csv of the actuator (linear solenoid valve) detected by the brake ECU 300 (actuator operation frequency counting unit 320). Then, in step S250, the HV-ECU 302 sets the regeneration limit rate Pr based on the cumulative operation count Csv.

  Referring to FIG. 12, step S250 includes steps S251 to S253. In step S251, the HV-ECU 302 determines whether or not the cumulative operation count Csv exceeds a predetermined threshold value Nth. As described above, the threshold value Nth can be determined according to the cumulative number of operations of the linear solenoid valve that is assumed when the seal structure of the contact 506 is designed. That is, when the cumulative number of operations Csv exceeds the threshold value Nth, there is a concern about a decrease in the hydraulic pressure response rate due to deterioration of the sealing performance.

  The HV-ECU 302 advances the process to step S252 and sets the regeneration limit rate Pr to a normal value until the cumulative operation count Csv exceeds the threshold value Nth (NO determination in S251).

  On the other hand, when the cumulative number of operations Csv exceeds the threshold value Nth (when YES is determined in S251), the HV-ECU 302 proceeds to step S253 and sets the regeneration limit rate Pr to the value set by S252. Set lower than (normal value).

  FIG. 13 shows the relationship between the cumulative number of operations of the actuator (linear solenoid valve) and the set value of the regeneration limit rate in the embodiment of the present invention.

  Referring to FIG. 13, the cumulative operation count Csv increases as the usage time (years) elapses. Until the cumulative operation count Csv reaches the threshold value Nth, the regeneration limit rate Pr is set to Pr = R1. In this case, recovery energy can be recovered by setting R1 as high as possible according to the hydraulic pressure response rate.

  On the other hand, after time Y1 when the cumulative number of operations Csv exceeds the threshold value Nth, there is a concern about a decrease in the hydraulic pressure control response rate in the brake hydraulic pressure circuit 80. Therefore, the regeneration limit rate Pr is Pr = R2 (R2 <R1). ). Along with this, the margin current ΔImg in the Li precipitation suppression control is also set to be large.

  As a result, it is possible to prevent instantaneous fluctuation of the vehicle braking force due to regenerative restriction during brake cooperative control due to a decrease in hydraulic pressure control responsiveness caused by an increase in the cumulative number of operations of the actuator (linear solenoid valve). .

  Note that, as indicated by a dotted line in FIG. 13, the regeneration limit rate may be gradually decreased in a plurality of stages. As for the mode of reducing the regenerative restriction rate Pr in accordance with the increase of the cumulative operation number Csv, it is arbitrarily selected according to the decrease characteristic of the hydraulic pressure response rate with the increase of the cumulative operation number of the actuator in the brake hydraulic circuit 80. It is possible to set.

  Referring to FIG. 11 again, in step S255, HV-ECU 302 sets margin current ΔImr in accordance with regeneration limit rate Pr set in step S250.

  As described above, when the regeneration limit rate is increased in order to increase the charge power limit degree, the charge current can be quickly reduced when Ib <Itag. For this reason, since the conditions for starting the regeneration limitation can be relaxed, the margin current ΔImr can be reduced. As a result, the amount of energy recovered by regenerative braking can be increased.

  Thus, it is necessary to change the margin current ΔImr in the Li precipitation suppression control with a characteristic opposite to the regeneration limit rate. That is, the margin current ΔImr is set to be smaller as the regeneration restriction rate Pr at the time of regeneration restriction becomes higher. On the contrary, the margin current ΔImr is set to be larger as the regeneration limit rate Pr at the time of regeneration limitation is lower. As a result, it is possible to achieve both suppression of lithium metal precipitation and securing of the recovered energy amount by regenerative braking.

  From this point of view, a map in which the relationship between the regeneration limit rate Pr and the margin current ΔImr is predetermined can be created in advance. This map is stored in advance in a memory (not shown) in the HV-ECU 302. In step S255, the margin current ΔImr can be set by referring to the map based on the regeneration limit rate Pr set in step S250.

  Furthermore, in step S260, the HV-ECU 302 executes a current control calculation for controlling Li precipitation suppression. That is, as described in FIG. 6, based on the method shown in Patent Document 4, 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 S255 with respect to the allowable input current value Ilim.

  Further, in step S270, the HV-ECU 302 compares the battery current Ib input in step S210 with the input current limit target value Itag calculated in step S260. The processing in steps S255 to S270 corresponds to the function of the current determination unit 350 in FIG.

  When Ib> Itag (NO determination in S270), HV-ECU 302 turns off flag FLG shown in FIG. 9 because the charging current has not reached Itag. At this time, the HV-ECU 302 turns off the regeneration restriction in step S280. In this case, in step S285, Win0 set in step S230 becomes the Win of battery 18 as it is (Win = Win0).

  On the other hand, when Ib <Itag (YES determination in S270), HV-ECU 302 turns on flag FLG because the charging current has reached Itag. At this time, the HV-ECU 302 turns on regeneration restriction in step S290. 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 S295. 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 processing in steps S230 and S280 to S295 corresponds to the function of the Win setting unit 360 in FIG.

  As described above, according to the present embodiment, in a vehicle equipped with a lithium ion secondary battery, the hydraulic pressure control in the brake hydraulic circuit 80 is performed when the charging current is limited for the Li deposition suppression control during regenerative power generation. Based on the cumulative number of operations of the actuator (for example, linear solenoid valve), charging power limitation (regeneration limitation) is performed in the Li deposition suppression control.

  Therefore, even if the response rate of the hydraulic pressure control decreases according to the cumulative number of times the actuator is used, the charging power limit (regeneration limit) by the Li deposition suppression control can be limited so that the hydraulic braking force is not delayed. As a result, it is possible to prevent the user from feeling uncomfortable due to charging power limitation (regeneration limitation) by Li deposition suppression control. In addition, since the number of times the actuator is used is small, the condition for starting the charging power limitation can be relaxed (that is, the margin current ΔImr can be reduced) in a state where the possibility of a decrease in the response rate of the hydraulic pressure control is low. Thereby, the energy efficiency (namely, fuel consumption) of a vehicle can be improved by ensuring regenerative energy to the maximum.

  The vehicle to which the brake cooperative control according to the embodiment of the present invention is applied is not limited to the hybrid vehicle 5 illustrated in FIG. The present invention is not limited to the number of motors (motor generators) to be mounted and driving as long as the braking force is secured by a combination of the regenerative braking force by the motor and the hydraulic braking force according to the supply of the hydraulic pressure. Regardless of the system configuration, in addition to hybrid vehicles, the invention can be commonly applied to all electric vehicles including electric vehicles not equipped with engines and fuel cell vehicles. In particular, the configuration of the hybrid vehicle is not limited to the example shown in FIG. 1, and it is confirmed that the present invention can be applied to any configuration including a parallel hybrid vehicle. Describe. Moreover, even if the vehicle is not equipped with a traveling motor, the present invention can be applied if a motor that generates regenerative braking force is installed.

  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.

  The present invention can be applied to an electronically controlled brake system in which a regenerative braking force and a hydraulic braking force are coordinated in a vehicle equipped with a lithium ion secondary battery.

  5 Hybrid vehicle, 10 Braking device, 12 Drive wheel, 14 Reduction gear, 16 Power control unit, 18 Battery, 19 Battery sensor, 20 Engine, 22 Brake pedal, 34 Engine speed sensor, 36 IG switch, 40 1st MG, 41 , 61 Rotation position sensor, 60 2nd MG, 80 Brake hydraulic circuit, 81 Hydraulic booster, 82 Pump motor, 83 Accumulator, 84 Reservoir, 85 Hydraulic control circuit, 86-88 Hydraulic sensor, 89 Stroke simulator, 90, 91 Fluid path, 100 Power split mechanism, 102 1st ring gear, 102a Ring gear shaft, 104 1st pinion gear, 106 1st carrier, 108 1st sun gear, 160 Brake caliper, 161 Wheel cylinder, 162 Brake de Disk, 164 drive shaft, 165 vehicle speed sensor, 200 transmission, 202 second ring gear, 204 second pinion gear, 206 second carrier, 208 second sun gear, 300 brake ECU, 302 HV-ECU, 304 engine ECU, 306 power ECU 310 communication bus, 315 hydraulic pressure control unit, 320 actuator operation frequency count unit, 330 regeneration limit rate setting unit, 340 SOC calculation unit, 350 current determination unit, 360 Win setting unit, 501 solenoid core, 502 plunger, 505 energizing Means, 506 contacts, Csv cumulative number of operations (actuator), Fe electromagnetic force, FLG flag (regenerative limit), FLH, FRH, RLH, RRH Control solenoid valve (holding valve), FLR, FRR, RLR, RRR Control solenoid valve (pressure reducing valve), Fs biasing force, Ib battery current, ΔImr margin current, Ilim allowable input current value, Ilim [0] initial value (allowable input current value), Itag input current limit target value, Nm1, Nm2 rotation Number (MG), Nth threshold value (actuator cumulative operation count), Pac accumulator pressure, Pr regeneration limit rate, Prg regulator pressure, Prt hydraulic pressure response rate, Pwc * command value (wheel cylinder pressure), Pwc detection value (wheel Cylinder pressure), SCC, SMC, SRC, SSC switching solenoid valve, SLA, SLR linear solenoid valve (actuator), Svl control signal (brake hydraulic circuit), Tb battery temperature, Tbk * hydraulic brake torque, Tr * required braking Torque, V vehicle speed, Vb Battery voltage.

Claims (4)

A battery composed of a lithium ion secondary battery, a braking device configured to cause a braking force according to a supplied hydraulic pressure to act on the wheel, and a rotational force can be transmitted between the wheels. A vehicle control device comprising: a motor generator; and a power controller for performing bidirectional power conversion between the battery and the motor generator so as to control an output torque of the motor generator. ,
Based on the charge / discharge history of the battery, charge control means for adjusting the charge power upper limit value of the battery so as to prevent the negative electrode potential of the battery from decreasing to a lithium reference potential;
The hydraulic braking force by the braking device and the regenerative braking force with respect to the required braking force corresponding to the brake pedal operation so that the motor generator generates the regenerative braking force within the range of the adjusted charging power upper limit value. Braking control means for determining sharing;
A counting means for counting the cumulative number of operations of the actuator for controlling the hydraulic pressure supplied to the braking device,
The charge control means includes
Setting means for reducing a limit degree of the charging power upper limit value when limiting the charging power upper limit value in order to prevent a decrease in the negative electrode potential according to the cumulative number of operations detected by the counting means. A vehicle control apparatus including: When the cumulative operation count exceeds a predetermined threshold, the setting means sets a limit rate indicating a rate of time change when the charge power upper limit value is lowered, and the cumulative operation count is less than the threshold. Set to a lower value,
The charge control means includes
Based on the charge / discharge history, the input allowable current value is sequentially set as the maximum current at which lithium metal does not deposit on the negative electrode of the battery, and the input allowable current value is set to a smaller value as the limit rate is higher. Means for determining the input current limit target value to have a margin of
The vehicle control device according to claim 1, further comprising: means for decreasing the charge power upper limit value according to the limit rate when a charge current of the battery exceeds the input current limit target value.   The vehicle control device according to claim 1, wherein the actuator is a solenoid valve configured to be opened and closed when the hydraulic pressure is changed.   The vehicle control device according to claim 1, wherein the condition for starting the restriction of the charging power upper limit value is relaxed as the restriction degree is higher.

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