Vehicle control system

Abstract

To suppress rewrite frequency of SOC (State of Change) stored to a non-volatile memory.SOLUTION: An ECU 300 has a non-volatile memory 302a. An SOC acquisition part 310 acquires SOCc to be a current SOC of a battery. A ΔSOC calculation part 320 calculates difference ΔSOC (=|SOCm-SOCc|) between SOCm (stored SOC) and the SOCc stored to the non-volatile memory 302a. A rewrite part 330 rewrites SOCm stored to the non-volatile memory 302a with SOCc in the case of ΔSOC>threshold S1 when charged, ΔSOC>threshold S2 when discharged, and ΔSOC>specified value α during ON→OFF operation of an ignition switch.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to a control device for a vehicle, and particularly to a control device for a vehicle equipped with a driving battery.

Background Art

[0002] Japanese Patent Application Laid-Open No. 2002-71360 (Patent Document 1) discloses that writing (storing) vehicle position information in a non-volatile memory that retains the written content even when the power supply is cut off is executed only when the vehicle is in a stopped state. This makes it possible to reliably store and hold the vehicle position information immediately before the power supply is cut off without providing a power supply that can be constantly supplied.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In an electric vehicle, the state of charge (SOC) of a battery is used for various controls of the vehicle. It is desirable that the SOC information be stored in a non-volatile memory so that it does not disappear even when the power supply to the control device is cut off.

[0005] Due to deterioration or the like, the non-volatile memory has a limit on the number of write operations (storage times). When the number of write operations reaches the upper limit, the SOC information may not be stored properly. Therefore, for example, if the SOC information stored in the non-volatile memory is rewritten every time the electric vehicle stops, there is a concern that the number of write operations will increase unnecessarily and exceed the upper limit of the number of rewrites of the non-volatile memory.

[0006] The purpose of this disclosure is to reduce the number of write cycles for SOCs stored in non-volatile memory. [Means for solving the problem]

[0007] The vehicle control device of this disclosure is a control device for a vehicle equipped with a drive battery. The control device includes a non-volatile memory. The control device includes an SOC acquisition unit that acquires the current SOC, which is the current state of charge (SOC) of the battery; a ΔSOC acquisition unit that acquires ΔSOC, which is the difference between the stored SOC stored in the non-volatile memory and the current SOC; and a rewrite unit that, when ΔSOC is greater than a predetermined value, rewrites the stored SOC stored in the non-volatile memory to the current SOC.

[0008] With this configuration, when ΔSOC, which is the difference between the stored SOC stored in non-volatile memory and the current SOC, is greater than a predetermined value, the stored SOC is rewritten, thereby suppressing the number of rewrites. Furthermore, by setting the predetermined value to a value acceptable when executing various controls, it becomes possible to perform various controls using the stored SOC.

[0009] Preferably, the predetermined value may be set based on the vehicle speed.

[0010] In this configuration, the predetermined value is set based on the vehicle speed. For example, when the vehicle speed is high, such as when driving on a highway, the rate of decrease of SOC increases, so ΔSOC becomes larger. When the vehicle speed is high, the number of rewrites can be reduced by increasing the predetermined value compared to when the vehicle speed is low. When the vehicle speed is high (while driving), the possibility of the control device's power being cut off is low, so the possibility of performing various controls using the stored SOC is low, and even if the discrepancy between the current SOC and the stored SOC is large, the impact is small.

[0011] Preferably, the predetermined value may be set to different values ​​during battery charging and discharging.

[0012] When the current SOC cannot be obtained, various controls are performed using the stored SOC stored in non-volatile memory, and the stored SOC may also be used as the battery's SOC display. When the battery is discharged, if the current SOC (actual SOC) is smaller than the stored SOC, the actual amount of dischargeable power will be less than the amount of dischargeable power indicated by the stored SOC (in the case of driving, the actual driving range will be shorter than the driving range indicated by the stored SOC), which may cause disadvantage to the user.

[0013] With this configuration, for example, by setting a predetermined value during discharge to be smaller than the predetermined value during charging, the above-mentioned disadvantages during discharge can be reduced, and during charging, the number of rewrite cycles of the non-volatile memory can be reduced.

[0014] Preferably, the rewriting unit may rewrite the stored SOC stored in the non-volatile memory to the current SOC when the ignition switch is operated from ON to OFF and ΔSOC is greater than a predetermined value.

[0015] When the ignition switch is operated from ON to OFF, the saved SOC stored in non-volatile memory is overwritten with the current SOC. The next time the ignition switch is operated ON, the saved SOC is read from the non-volatile memory, and various controls are executed using the read saved SOC.

[0016] With this configuration, when the ignition switch is operated from ON to OFF, if ΔSOC is greater than a predetermined value, the non-volatile memory is rewritten, thereby reducing the number of rewrites. [Effects of the Invention]

[0017] According to this disclosure, the number of write cycles for the SOC stored in non-volatile memory can be suppressed. [Brief explanation of the drawing]

[0018] [Figure 1]This is an overall configuration diagram of a vehicle according to the present embodiment. [Figure 2] This is a diagram showing functional blocks configured in the ECU in the present embodiment. [Figure 3] An example of a map showing a rewrite area is shown. [Figure 4] This is a flowchart showing an example of rewrite processing executed in the ECU.

Embodiments for Carrying Out the Invention

[0019] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and their description will not be repeated.

[0020] FIG. 1 is an overall configuration diagram of a vehicle according to the present embodiment. In the present embodiment, the vehicle 1 is, for example, an electric vehicle. The vehicle 1 includes a motor generator (MG) 10 that is a rotary electric machine, a power transmission gear 20, drive wheels 30, a power control unit (PCU) 40, a system main relay (SMR) 50, a battery 100, a monitoring unit 200, and an electronic control unit (ECU) 300 which is an example of a control device.

[0021] The MG 10 has functions as an electric motor (motor) and as a generator. The output torque of the MG 10 is transmitted to the drive wheels 30 via a power transmission gear 20 configured to include a reduction gear, a differential device, and the like.

[0022] When the vehicle 1 is braking, the MG10 is driven by the drive wheels 30 and the MG10 operates as a generator. Thereby, the MG10 also functions as a braking device that performs regenerative braking to convert the kinetic energy of the vehicle 1 into electric power. The regenerative electric power generated by the regenerative braking force in the MG10 is stored in the battery 100. The PCU40 is a power conversion device that converts power bidirectionally between the MG10 and the battery 100. The SMR50 is electrically connected to the power line connecting the battery 100 and the PCU40, and when the SMR50 is closed (ON), power is exchanged between the battery 100 and the PCU40.

[0023] The battery 100 stores electric power for driving the MG10. The battery 100 is a rechargeable DC power source (secondary battery), for example, a plurality of single cells (battery cells) are stacked and electrically connected in series.

[0024] The monitoring unit 200 includes a voltage sensor 210 that detects the voltage VB of the battery 100, a current sensor 220 that detects the current IB input to and output from the battery 100, and a temperature sensor 230 that detects the temperature TB of the battery 100.

[0025] The vehicle 1 is provided with a DC inlet 60, and a connector 420 provided at the tip of a charging cable 410 of an external DC power source (charging facility) 400 is configured to be connectable. When the charging relay 70 is closed, external charging (rapid charging) of the battery 100 is executed. In addition to external charging, a V2H device 600 capable of external discharging (power feeding) from the battery 100 may be connected to the DC inlet 60.

[0026] The vehicle 1 is provided with an AC inlet 80, and a connector 520 provided at the tip of a charging cable 510 of an external AC power source (charging facility) 500 is configured to be connectable. When the charging relay 90 is closed, external charging (normal) of the battery 100 is executed using the in-vehicle charger 130.

[0027] The ECU 300 includes a CPU (Central Processing Unit) 301 and memory (including, for example, ROM (Read Only Memory) and RAM (Random Access Memory)) 302. The memory 302 also includes rewritable non-volatile memory (for example, flash memory) 302a. The ECU 300 operates on power supplied from the auxiliary battery 110 via a power relay 111. Based on signals received from the monitoring unit 200, signals from various sensors (for example, vehicle speed SPD detected by the vehicle speed sensor 260, accelerator opening, etc.), and information such as maps and programs stored in the memory 302, the ECU 300 controls each device to bring the vehicle 1 to a desired state. For example, based on signals received from the monitoring unit 200, the ECU 300 calculates the State of Charge (SOC) of the battery 100 and uses this SOC to control the charging and discharging of the battery 100. The ON / OFF state of the ignition switch (power switch) 250 is also input to the ECU 300.

[0028] Figure 2 shows the functional blocks configured in the ECU 300 in this embodiment. The SOC acquisition unit 310 acquires the current SOC of the battery 100, SOCc (current SOC), from the voltage VB and current IB. For example, SOCc may be calculated by combining the OCV (Open Circuit Voltage) method and the Coulomb current method. If the monitoring unit 200 is a BMS (Buttery Management System), the EMS (monitoring unit 200) may calculate SOCc and acquire the SOCc calculated by the BMS.

[0029] The ΔSOC calculation unit 320 reads SOCm (stored SOC), which is the SOC stored in the non-volatile memory 302a, and calculates ΔSOC, which is the difference between SOCm and SOCc (ΔSOC = |SOCm - SOCc|).

[0030] The rewrite unit 330 determines whether or not the SOCm needs to be rewritten, and if it does, it rewrites the SOCm stored in the non-volatile memory 302a. Figure 3 shows an example of a map showing the rewrite area. In Figure 3, the vertical axis is ΔSOC, with 0 as the base and increasing values ​​in the vertical direction. Above 0 is the rewrite area during charging, and below 0 is the rewrite area during discharging. During charging of the battery 100, the area where ΔSOC is greater than threshold S1 is set as the rewrite area. During discharging, the area where ΔSOC is greater than threshold S2 is set as the rewrite area. As shown in Figure 3, thresholds S1 and S2 are set to larger values ​​when the vehicle speed SPD is high. Also, when the vehicle speed SPD is the same, threshold S2 (during discharging) is set to a smaller value than threshold S1 (during charging). Thresholds S1 and S2 correspond to an example of the "predetermined values" in this disclosure.

[0031] The rewriting unit 330 determines whether it is charging or discharging based, for example, on the direction (sign of current IB) of the current IB detected by the current sensor 220. Then, based on the ΔSOC during charging and the vehicle speed SPD, the rewriting unit 330 uses the map in Figure 3 to determine if it is a rewriting area when ΔSOC is greater than threshold S1, and if it is a standby area when ΔSOC is less than or equal to threshold S1. Based on the ΔSOC during discharging and the vehicle speed SPD, the rewriting unit 330 uses the map in Figure 3 to determine if it is a rewriting area when ΔSOC is greater than threshold S2, and if it is a standby area when ΔSOC is less than or equal to threshold S2. When the rewriting unit 330 determines that it is a rewriting area, it rewrites the SOCm stored in the non-volatile memory 302a to SOCc.

[0032] Furthermore, when the ignition switch 250 is operated from ON to OFF, if ΔSOC is greater than a predetermined value α, the rewriting unit 330 rewrites SOCm stored in the non-volatile memory 302a to SOCc.

[0033] Figure 4 is a flowchart showing an example of a rewriting process performed in the ECU 300. This flowchart is executed repeatedly while the ECU 300 is enabled to start (for example, when the ignition switch is ON, when the battery 100 is being externally charged, or when it is being externally discharged (powered)). In step 10 (hereinafter, steps are abbreviated as "S"), the SOCc (current SOC) of the battery 100 is obtained. The SOCc may be calculated from the voltage VB and current IB, or if the monitoring unit 200 is a BMS, the SOCc calculated by the monitoring unit 200 (BMS) may be obtained.

[0034] In the following step S11, SOCm (stored SOC) is read from the non-volatile memory 302a. In S12, ΔSOC (=|SOCm-SOCc|) is calculated.

[0035] In S13, it is determined whether the ignition switch 250 has been operated from ON to OFF. If the ignition switch 250 has been operated from ON to OFF in S13 and the result is positive, proceed to S15; otherwise, proceed to S14.

[0036] In S14, based on ΔSOC and vehicle speed SPD, the map in Figure 3 is used to determine whether or not it is a rewrite area. When the battery 100 is charging, if ΔSOC is greater than or equal to threshold S1, it is determined to be a rewrite area and the process proceeds to S16. When the battery is discharging, if ΔSOC is greater than or equal to threshold S2, it is determined to be a rewrite area and the process proceeds to S16. If it is a standby area, it is determined to be negative, and the routine ends.

[0037] In S15, it is determined whether ΔSOC is greater than or equal to a predetermined value α. If the determination is positive, the process proceeds to S16. If the determination in S15 is negative, the current routine is terminated.

[0038] In S16, the SOCm stored in the non-volatile memory 302a is rewritten to SOCc. If the result in S13 is positive, after the processing in S15 and S16 is completed, the power relay 111 may be shut off to cut off the power supply to the ECU 300.

[0039] According to this embodiment, when ΔSOC, which is the difference between SOCm (stored SOC) and SOCc (current SOC) stored in the non-volatile memory 302a, is greater than a predetermined value (threshold S1, S2, predetermined value α), SOCm is rewritten, thereby suppressing the number of rewrites. Furthermore, by setting the predetermined value to an acceptable value when executing various controls, various controls using SOCm can be performed.

[0040] According to this embodiment, thresholds S1 and S2 are set based on the vehicle speed SPD, and when the vehicle speed SPD is high, thresholds S1 and S2 are set to be larger compared to when the vehicle speed SPD is low. When the vehicle speed SPD is high, such as when driving on a highway, the rate of decrease in SOCc increases and ΔSOC becomes large, but by making the thresholds S1 and S2 larger compared to when the vehicle speed is low, the number of rewrites can be reduced. In addition, when the vehicle speed SPD is high (while driving), the auxiliary battery 110 is not removed, the possibility of the auxiliary battery 110's charge being depleted is low, and the possibility of the ECU 300's power being cut off is low, so the possibility of various controls using SOCc being interrupted is low, and even if the discrepancy between SOCc and SOCm is large, the effect can be reduced.

[0041] In this embodiment, threshold S1 (threshold during charging) and threshold S2 (threshold during discharging) are set to different values, with threshold S2 being set smaller than threshold S1. When SOCc cannot be obtained, various controls are performed using SOCm stored in the non-volatile memory 302a, and SOCm may also be used as the SOC display for battery 100. During discharge, if SOCc (actual SOC) is smaller than SOCm, the actual dischargeable power will be smaller than the dischargeable power amount indicated by the displayed SOCm (in the case of driving, the actual driving distance will be shorter than the driving distance indicated by SOCm), which may cause disadvantage to the user. By setting threshold S2 smaller than threshold S1, the above disadvantage during discharge can be reduced, and during charging, since threshold S1 is large, it is possible to reduce the number of rewrites of the non-volatile memory 302a.

[0042] According to this embodiment, when the ignition switch 250 is operated from ON to OFF, if ΔSOC is greater than a predetermined value α, the SOCm stored in the non-volatile memory 302a is rewritten to SOCc. Therefore, compared to the case where SOCm is rewritten each time the ignition switch 250 is operated from ON to OFF, the number of rewrites of the non-volatile memory 302a can be suppressed.

[0043] In the above embodiment, the ECU 300 that controls each device was configured with the functional block shown in Figure 2, and the flowchart in Figure 4 was executed. However, the battery ECU that controls the charging and discharging of the battery 100, or the BMS (monitoring unit 200), may also be equipped with non-volatile memory and perform these functions. Furthermore, the vehicle 1 may be any electric vehicle, and may be a PHEV (Plug-in Hybrid Electric Vehicle) or HEV (Hybrid Electric Vehicle) equipped with an internal combustion engine, or an FCEV (Fuel Cell Electric Vehicle).

[0044] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the present invention is indicated by the claims rather than by the description of the embodiments above, and all modifications within the meaning and scope equivalent to the claims are intended to be included. [Explanation of Symbols]

[0045] 1 Vehicle, 10 Motor Generator (MG), 20 Drive Transmission Gear, 30 Drive Wheel, 40 PCU, 50 SMR, 60 DC Inlet, 80 AC Inlet, 100 Battery, 110 Auxiliary Battery, 111 Power Relay, 200 Monitoring Unit, 210 Voltage Sensor, 220 Current Sensor, 250 Ignition Switch, 260 Vehicle Speed ​​Sensor, 300 ECU, 301 CPU, 302 Memory, 302a Non-Volatile Memory, 400 DC Power Supply, 500 AC Power Supply, 520 Connector, 600 V2H Equipment.

Claims

1. A control device for a vehicle equipped with a drive battery, The control device is equipped with non-volatile memory, The control device is An SOC acquisition unit that acquires the current SOC, which is the current SOC of the aforementioned battery, A ΔSOC acquisition unit acquires ΔSOC, which is the difference between the stored SOC stored in the non-volatile memory and the current SOC. The system includes a rewriting unit that, when the ΔSOC is greater than a predetermined value, rewrites the stored SOC stored in the non-volatile memory to the current SOC. A vehicle control device in which, when the ignition switch is ON, the predetermined value is set to be larger when the vehicle speed is high compared to when the vehicle speed is low.

2. A control device for a vehicle equipped with a drive battery, The control device is equipped with non-volatile memory, The control device is An SOC acquisition unit that acquires the current SOC, which is the current SOC of the aforementioned battery, A ΔSOC acquisition unit acquires ΔSOC, which is the difference between the stored SOC stored in the non-volatile memory and the current SOC. The system includes a rewriting unit that, when the ΔSOC is greater than a predetermined value, rewrites the stored SOC stored in the non-volatile memory to the current SOC. A vehicle control device wherein, when the ignition switch is ON and the vehicle speed is the same, the predetermined value during battery discharge is set to be smaller than the predetermined value during battery charging.

3. A control device for a vehicle equipped with a drive battery, The control device is equipped with non-volatile memory, The control device is An SOC acquisition unit that acquires the current SOC, which is the current SOC of the aforementioned battery, A ΔSOC acquisition unit acquires ΔSOC, which is the difference between the stored SOC stored in the non-volatile memory and the current SOC. The system includes a rewriting unit that, when the ΔSOC is greater than a predetermined value, rewrites the stored SOC stored in the non-volatile memory to the current SOC. With the ignition switch in the ON position, When the vehicle speed is high, the predetermined value is set to be larger compared to when the vehicle speed is low, A vehicle control device wherein, when the vehicle speed is the same, the predetermined value during battery discharge is set to be smaller than the predetermined value during battery charging.

4. The vehicle control device according to any one of claims 1 to 3, wherein the rewriting unit rewrites the stored SOC stored in the non-volatile memory to the current SOC when the ignition switch is operated from ON to OFF and the ΔSOC is greater than the predetermined value.

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