ECU control system and ECU control method

Abstract

In an ECU control system 100, a management ECU 30 monitors a memory usage amount of a downstream memory, and before the memory usage amount exceeds an upper limit capacity of the downstream memory, executes data migration for migrating vehicle data stored in the downstream memory from the downstream memory to the management ECU, and a downstream ECU deletes, from the downstream memory, the vehicle data migrated to the management ECU 30.

Description

ECU Control System and ECU Control Method

[0001] The present invention relates to an ECU control system and an ECU control method.

[0002] Conventionally, a vehicle system in which a communication unit and a plurality of ECUs are connected on an in-vehicle network (for example, a CAN network) is known. For example, in the vehicle system described in Patent Document 1, each ECU collects the update state of the ECU software, collects data items representing the state of the vehicle, and temporarily stores them in the RAM. Also, among the plurality of ECUs, the ECU that can communicate with the data center collects the update state of the software of each ECU and collects data items representing the state of the vehicle. For example, one ECU calculates the driving route information under certain conditions and outputs it on the in-vehicle network, and another ECU that can communicate with the data center records the driving route information acquired from the one ECU every minute and transmits it to the data center every three hours.

[0003] Japanese Patent Application Laid-Open No. 2022-107913

[0004] In the vehicle system described in Patent Document 1, the plurality of ECUs each have a RAM and store the collected data in the RAM. However, when the usage capacity of the RAM of one ECU reaches the upper limit capacity, one ECU cannot store new data even if it collects new data, so there is a problem that other ECUs cannot acquire new data from one ECU.

[0005] The problem to be solved by the present invention is to provide an ECU control system and an ECU control method that can transfer vehicle data from one ECU to another ECU before the memory usage amount of one ECU exceeds the upper limit capacity of the memory.

[0006] The present invention solves the above problem by monitoring the memory usage amount of the downstream memory by the management ECU 30, transferring the vehicle data stored in the downstream memory from the downstream memory to the management ECU before the memory usage amount exceeds the upper limit capacity of the downstream memory, and deleting the transferred vehicle data from the downstream memory.

[0007] According to the present invention, vehicle data can be transferred from the downstream ECU to the management ECU before the memory usage of the downstream ECU exceeds the upper limit of the memory capacity.

[0008] Figure 1 is a schematic diagram of the configuration of the ECU control system according to this embodiment. Figure 2 is a flowchart showing the control flow executed by the management ECU in the ECU control method of this embodiment.

[0009] Hereinafter, embodiments of the ECU control system according to the present invention will be described with reference to the drawings.

[0010] Figure 1 is a schematic diagram of the configuration of the ECU control system 100 and server 1 according to this embodiment. The ECU control system 100 according to this embodiment is a system that controls a plurality of ECUs and is mounted on a vehicle. The vehicle is a hybrid vehicle or electric vehicle equipped with an engine and a motor. The ECU control system 100 may also be mounted on a vehicle that obtains power from an engine (ICE vehicle). The ECU control system 100 includes a communication unit 10, an OBD terminal 20, a management ECU 30, a VCM 40, an IVI 41, a BMS 42, an ADCU 50, a camera 51, a LiDAR 52, a BCM 60, an ACU 61, a Meter 62, and buses 400-402, 500-502, and 600-602. The ECUs and loads (onboard devices) included in the ECU control system 100 are connected by an in-vehicle communication network such as CAN or LIN.

[0011] Server 1 communicates with the vehicle remotely and sends and receives data between the two. Server 1 performs tasks such as remote diagnostics, software updates, and vehicle data collection. Remote diagnostics involve connecting Server 1 and the vehicle wirelessly to access the vehicle remotely and diagnose its condition. Specifically, Server 1 sends a diagnostic command to the vehicle to be diagnosed, specifying the data to be extracted from the vehicle. Server 1 may also send a diagnostic command after specifying the ECU to be diagnosed from among the ECUs included in the vehicle. Server 1 uses the data acquired from the vehicle to diagnose whether or not there is an abnormality in the vehicle. The data sent from the vehicle to Server 1 includes fault codes (DTCs), ECU logs, or data indicating the vehicle's driving status. In remote diagnostics, the diagnosis of whether or not there is an abnormality in the vehicle may be performed on the server side or on the vehicle side.

[0012] Software updates involve sending update data for the software included in the vehicle's ECU from Server 1 to the vehicle via OTA (over-the-air) communication (wireless communication), and the vehicle performing the software update. Server 1 stores the update data for updating the ECU software in a database and sends the update data to the vehicle in response to an update request. The update data is the latest software data. The update data may also include the time required for the software update. Server 1 manages campaigns in the database, including vehicle identification information (VIN) and ECU identification information (e.g., ECU name). For example, when the latest version of the ECU software is uploaded, Server 1 sends an update request signal to the vehicle to obtain the information necessary for the software update. The update request signal may include the software to be updated or the identification information (ID) of the ECU. The vehicle's ECU control system 100 sends a signal to Server 1, including ECU update information (version information), in response to a request from Server 1. Server 1 determines from the update information whether the ECU software is up to date. If Server 1 determines that the current version of the ECU is outdated, it sends the latest software (update data, reprogramming data) to the vehicle. The management ECU 30 of the vehicle's ECU control system 100 downloads the update data sent from Server 1. The ECU control system 100 then uses the update data to update the software of the ECU to be updated.

[0013] Server 1 communicates with vehicles and acquires vehicle data, including vehicle location information, images captured by in-vehicle cameras, vehicle speed information, and application operation history. Vehicle data acquired from multiple vehicles is used for business purposes by insurance companies, vehicle repair companies, application vendors, music and video distribution companies, etc. For example, when a vehicle accident occurs, insurance companies collect vehicle data to understand the accident scene from the vehicle's location information, vehicle speed, and captured images, and to calculate the compensation burden rate. Application vendors and music distribution companies also collect vehicle data to understand the usage history of applications and entertainment content such as music by vehicle users, and to provide users with recommended information on relevant applications, etc. In addition to collecting vehicle data from multiple vehicles, Server 1 may also transmit application data to vehicles. It should be noted that Server 1 is a general term for data centers that can communicate with multiple vehicles remotely, and it is not necessary for remote diagnosis, software updates, and vehicle data collection to all be performed by separate Server 1s.

[0014] Next, the configuration of the ECU control system 100 will be described. The communication unit 10 controls the in-vehicle communication device to connect to a communication network such as an internet line (mobile line) and communicates with the server 1.

[0015] The management ECU 30 connects multiple ECUs downstream and forwards signals transmitted from one ECU to another. In other words, the management ECU 30 functions as a gateway. The management ECU 30 is connected to the communication unit 10 and performs tasks such as software updates, remote diagnostics, and transmission of vehicle data based on commands input from the communication unit 10.

[0016] The management ECU 30 has a memory 30a. The management ECU 30 acquires vehicle data from multiple downstream ECUs and stores it in the memory 30a. The memory 30a stores update data for updating the software of the downstream ECUs, application data for realizing various functions, etc. The vehicle data may be stored in the memory 30a with an ID assigned to it so that the type of vehicle data and the ECU from which the vehicle data is acquired can be distinguished. When the management ECU 30 receives a request from the server 1 to collect vehicle data, it identifies the vehicle data corresponding to the request from the recorded data in the memory 30a and transmits it to the server 1 via the communication unit 10. For example, when performing a software update, the management ECU 30 acquires update data from the server 1 and stores it in the memory 30a. The management ECU 30 then transmits the update data to the ECU to be updated at a predetermined timing, such as during a time when the communication capacity of buses 400, 500, and 600 is low. Furthermore, for example, when adding an application in response to a request from a user or system, the management ECU 30 retrieves the data for the additional application from the server 1 and stores it in memory 30a. If the additional application is to be processed under the control of the management ECU 30, the management ECU 30a starts the additional application stored in memory. On the other hand, if the additional application is to be processed by a downstream ECU, the management ECU 30 may send the data for the additional application stored in memory 30a to the downstream ECU in order to install the additional application on the downstream ECU.

[0017] Memory 30a should use a large-capacity recording medium so that it can store vehicle data and the like acquired from multiple downstream ECUs. Although each of the multiple downstream ECUs has its own memory, the storage capacity of the memory of the downstream ECUs is small, as is the storage capacity of the memory 30a of the management ECU 30.

[0018] Incidentally, the memory 30a of the management ECU 30 requires a large-capacity recording medium to meet the needs described below. The ECU's software and applications are expected to be updated or added after the vehicle is shipped, and furthermore, software and application updates may be carried out not only by the vehicle manufacturer but also by other industries or individuals. For example, if an application to the vehicle is added or changed from outside the vehicle, the ECU control system 100 needs to send the application data to the ECU to be updated. Also, by designing the management ECU 30 so that the application's functions can be realized through the management ECU 30's processing, the application data can be stored in the management ECU 30's memory 30a rather than in the memory of the downstream ECU. Furthermore, since the management ECU 30 can communicate directly with the server 1 via the communication unit 10, when application updates or changes are anticipated, it is necessary to give the management ECU 30 the functions that can be realized by the application, thereby increasing the number of applications processed by the management ECU 30. To meet these needs, it is preferable to use a large-capacity recording medium for the memory 30a.

[0019] Furthermore, assuming that server 1 collects vehicle data from multiple vehicles, the vehicle data should be stored near the communication unit 10 in the vehicle's communication network. As shown in Figure 1, the management ECU 30 is connected closer to the communication unit 10, i.e., upstream, than the multiple downstream ECUs. Therefore, the storage location for vehicle data is preferably the memory 30a of the management ECU 30 rather than the memory of the downstream ECUs.

[0020] On the other hand, some applications and software, such as software related to vehicle operation, should be processed by downstream ECUs, so it is not practical to completely eliminate the memory of downstream ECUs. In this embodiment, to meet the above needs, the management ECU 30 has a memory 30a with a large storage capacity, and the multiple downstream ECUs each have a memory with a small storage capacity.

[0021] The management ECU 30 connects to the VCM 40 via bus 400, to the ADCU 50 via bus 500, and to the BCM 60 via bus 600.

[0022] This section describes the software update process performed by the management ECU 30. The management ECU 30 receives a software update command from the server 1 via the communication unit 10 to perform the software update. Based on the software update command, the management ECU 30 identifies the target ECU for software update, or an ECU that is eligible for software update. The target ECU is an ECU connected downstream of the management ECU 30, such as the VCM 40, ADCU 50, and BCM 60, or an ECU connected downstream of the VCM 40, ADCU 50, and BCM 60. The management ECU 30 downloads the software update data from the server 1 and stores it in the memory 30a within the management ECU 30. The management ECU 30 assigns a software update ID to the target ECU and sends and receives signals to and from the target ECU in order to send and receive the data necessary for the software update.

[0023] The target ECU has memory for storing software. In the software update sequence control, the target ECU communicates with the management ECU 30 to identify the version information and software associated with the software update ID from the data stored in memory, and then transmits the version information of the target ECU, installs the software, and activates the software. Specifically, when the target ECU receives the software, the software is written to the target ECU's memory (installation). With both the old and new software stored in memory, the target ECU switches the software to be processed from the old software to the new software (activation). In this embodiment, the process for such software updates does not necessarily have to be performed in a continuous sequence; the target ECU may first perform the software installation and then, separately, perform the activation when the management ECU 30 receives an update start request.

[0024] Remote diagnosis by the management ECU 30 will now be described. The management ECU 30 receives a diagnostic command from the server 1 via the communication unit 10 to perform remote diagnosis. Based on the diagnostic command, the management ECU 30 identifies the target ECU to be remotely diagnosed. The target ECU is an ECU connected downstream of the management ECU 30, or downstream of the VCM 40, ADCU 50, and BCM 60. The management ECU 30 assigns a diagnostic ID to the target ECU and transmits and receives signals with the target ECU in order to send and receive data used for remote diagnosis.

[0025] The target ECU stores diagnostic data in its memory, such as fault codes (DTCs), ECU logs, or data indicating the vehicle's driving status, as diagnostic data used for diagnosis. In the diagnostic sequence control, the target ECU communicates with the management ECU 30 to identify data associated with a diagnostic ID from the data stored in its memory, and transmits the identified diagnostic data to the management ECU 30. The management ECU 30 transmits the diagnostic data transmitted from the target ECU to the server 1. As a result, the management ECU 30 obtains diagnostic data from the target ECU that is used to diagnose the vehicle's condition. The management ECU 30 then transmits the diagnostic data obtained from the target ECU to the server 1 via the communication unit 10. The management ECU 30 may perform a remote diagnosis immediately after receiving a diagnostic command from the server 1, or it may perform a remote diagnosis at a predetermined execution timing. The predetermined execution timing may be a periodic timing such as once a day, or it may be the timing of switching the power switch (ignition switch or power switch) on and off.

[0026] The management ECU 30 monitors the memory usage of the memory contained in the downstream ECUs. In the following description, the term "downstream ECU" is used to refer to all ECUs connected downstream of the management ECU 30, and / or downstream of the VCM 40, such as the VCM 40, ADCU 50, and BCM 60, and the term "downstream memory" is used to refer to the memory within the downstream ECUs. Before the memory usage exceeds the upper limit capacity of the downstream memory, the management ECU 30 performs a data migration to transfer vehicle data stored in the downstream memory from the downstream memory to the management ECU 30. Details of the management ECU 30's monitoring of downstream memory usage and data migration will be described later.

[0027] VCM40, ADCU50, and BCM60 are ECUs and are connected downstream of the management ECU30 via buses 400, 500, and 600. Note that the communication unit 10, management ECU30, VCM40, ADCU50, and BCM60 are examples of multiple ECUs included in a vehicle, and the vehicle may include other ECUs. Furthermore, the management ECU30 is not limited to CM40, ADCU50, and BCM60, and may be connected to other ECUs.

[0028] The VCM (Vehicle Control Module) 40 is a control unit that controls the vehicle's drivetrain. The VCM 40 monitors the amount the accelerator pedal is pressed and controls the drivetrain, including the motor and engine. The VCM 40 stores vehicle data, such as control parameters of the drivetrain, in memory 40a while the vehicle is running. The control parameters of the drivetrain include the motor output torque, engine torque, and battery charge level. The upper limit capacity of memory 40a is smaller than the upper limit capacity of memory 30a. Downstream of the VCM 40 are connected an INV (Inverter) 41, a BMS (Battery Management System) 42, etc. The INV 41 is connected to bus 401, which branches off from bus 400 downstream of the VCM 40. The INV 41 is connected between the vehicle battery and the vehicle motor and converts the voltage of the vehicle battery to output to the vehicle motor. The BMS42 is a control unit (ECU) for controlling the charging and discharging of the vehicle battery. The BMS42 is connected to bus 402, which branches off from bus 400 downstream of the VCM40. If the vehicle is an ICE vehicle or a hybrid vehicle, the engine is connected downstream of the VCM40. Note that, in addition to the INV41 and BMS42, other devices such as a DCDC converter may be connected downstream of the VCM40.

[0029] The ADCU (Assisted Driving Control Unit) 50 is a control unit that assists in the driving of the vehicle. During autonomous driving, the ADCU 50 stores vehicle data indicating the surrounding environment of the vehicle in memory 50a. This vehicle data indicating the surrounding environment includes, for example, images captured by an onboard camera and measurement data from measurement sensors such as LiDAR 52. The upper limit capacity of memory 50a is smaller than the upper limit capacity of memory 30a. Cameras 51 and LiDAR 52 are connected downstream of the ADCU 50. Camera 51 is connected to bus 501, which branches off from bus 500 downstream of the ADCU 50. LiDAR 52 is connected to bus 502, which branches off from bus 500 downstream of the ADCU 50. The ADCU 50 detects white lines from the images captured by camera 51 and performs steering control to prevent the vehicle from deviating from its lane. Furthermore, the ADCU 50 measures the distance to the preceding vehicle from the data detected by the LiDAR 52, maintains the distance between the preceding vehicle and its own vehicle, and performs steering control and / or vehicle speed control to follow the preceding vehicle. Downstream of the ADCU 50, a memory containing high-precision map data may be connected in addition to the camera 51 and LiDAR 52. The ADCU 50 may also use a high-precision map to recognize the road layout and perform autonomous driving control that is appropriate to the current road conditions, in addition to lane departure prevention control and preceding vehicle following control.

[0030] The BCM (Body Control Module) 60 is a control unit that controls the overall functions of the vehicle body, including interior and exterior lighting, doors, windows, mirrors, and wipers. The BCM 60 stores vehicle data, including the operation history of in-vehicle equipment, in memory 60a. The upper limit of memory 60a is smaller than the upper limit of memory 30a. Downstream of the BCM 60 are connected the ACU (Airbag control Unit) 61, Meter 62, etc. The ACU 61 is connected to bus 601, which branches off from bus 600 downstream of the BCM 60. The Meter 62 is connected to bus 602, which branches off from bus 600 downstream of the ADCU 50. The ACU 61 is an airbag control unit (ECU). The Meter 62 displays speed, etc. Furthermore, downstream of the BCM60, other devices such as HVAC (Heating Ventilation and Air-Conditioning) may be connected, in addition to the ACU61 and Meter62.

[0031] Bus 400 is a bus that groups the VCM 40 and multiple ECUs downstream of the VCM 40. Bus 400 branches downstream of the VCM 40, and the branched buses 401 and 402 are each connected to an ECU or load. Note that buses 401 and 402 may be connected to more than one ECU or load, or multiple ECUs and / or multiple loads. Buses 500-502 and buses 600-602 have the same communication network as buses 400-402. Note that an ECU or load may be connected between the management ECU 30 and the VCM 40, ADCU 50, and BCM 60. In this way, the ECU control system 100 consists of multiple control groups divided according to the basic configuration of the vehicle. These control groups are also called domains. For example, in the example in Figure 1, there is a vehicle drive system domain including the VCM 40, a vehicle driving support system domain including the ADCU 50, and a body domain including the BCM 60. The domains include a multimedia domain that controls information display within the vehicle, a powertrain domain that controls the engine, and a chassis domain that controls the steering mechanism. By defining the domain configuration, the configurations of buses 400-402, 500-502, and 600-602 can be separated.

[0032] In this embodiment, the storage capacity of the memory 30a of the management ECU 30 is increased, and the storage capacity of the downstream memory is decreased. Since the downstream ECU cannot store large amounts of data in its downstream memory, when the memory usage reaches its upper limit, it becomes impossible to store new vehicle data in the downstream memory. Furthermore, the management ECU 30 has multiple ECUs connected downstream, and the way the downstream memory is used differs for each ECU. The number and frequency of vehicle rides, driving content, frequency and duration of use of autonomous driving functions, etc., differ depending on the user. For example, if the number and frequency of rides are high, the VCM 40 stores more vehicle data in memory 40a compared to when the number and frequency of rides are low. Also, if the autonomous driving function is used frequently, the ADCU 50 stores more vehicle data in memory 50a compared to when the autonomous driving function is used infrequently. In other words, the usage capacity of the downstream memory differs depending on the driving scene and the way the user uses the vehicle, and also differs for each downstream ECU.

[0033] Therefore, the management ECU 30 monitors the memory usage of the downstream memory in the following manner. The management ECU 30 predicts the memory usage of the downstream memory in order to monitor memory usage. The management ECU 30 predicts the memory usage of the downstream memory based on the driver's driving history and / or the operation history of the in-vehicle equipment. For example, if a user uses the vehicle only during specific time periods, such as during commuting, the vehicle will be driven during those specific time periods. For example, since the VCM 40 stores vehicle data such as the output torque of the motor in memory 40a while the vehicle is running, the time periods when the VCM 40 stores a lot of vehicle data in memory 40a will be specific time periods such as during commuting. By identifying past driving time periods and the amount of data recorded in memory from the driving history and / or the operation history of the in-vehicle equipment, the management ECU 30 can calculate the trend of driving time periods and the amount of data recorded in the downstream memory, and use the calculation results to predict the memory usage of the downstream memory.

[0034] The management ECU 30 may predict the memory usage of the downstream memory based on the software update history. For example, assume that the software update is performed after the vehicle's power switch (also called the ignition switch or main switch) is switched from on to off. For example, if the user frequently uses the vehicle during a specific period such as a holiday, the software update will also be performed during that specific period. When the software is updated, the downstream ECU 30 stores data in the downstream memory to download the update data and record data such as the update date. By identifying the period during which the software update was performed and the amount of data recorded in memory from the software update history, the management ECU 30 can calculate the trend of the time periods in which data is stored in the downstream memory and the amount of data recorded in the downstream memory, and use the calculation results to predict the memory usage of the downstream memory.

[0035] The management ECU 30 may also predict the memory usage of downstream memory based on the usage history of downstream memory. The management ECU 30 identifies the storage time and amount of data recorded for vehicle data stored in downstream memory from the vehicle data acquired from the downstream ECU. The management ECU 30 identifies the storage time and amount of data for vehicle data for each of the multiple downstream memory units. Then, the management ECU 30 can predict the memory usage for each memory unit from the time series of the identified storage time and amount of data. In this way, the management ECU 30 may predict the memory usage (predicted value) based on at least one of the following: the driving history of the vehicle driver, the operation history of in-vehicle equipment, the update history of the software included in the downstream ECU, and the usage history of downstream memory.

[0036] The management ECU 30 may monitor the memory usage of downstream memory by measuring the memory usage of downstream memory. The downstream ECU transmits the current memory usage of downstream memory to the management ECU 30. The management ECU 30 may send a request command to the downstream ECU to output usage data indicating the current memory usage. The downstream ECU may then transmit usage data indicating the current memory usage to the management ECU 30 in response to the request command from the management ECU 30. The downstream ECU may also transmit data indicating the current memory usage to the management ECU 30 at predetermined timings or predetermined intervals. For example, the downstream ECU transmits usage data indicating the current memory usage to the management ECU 30 when the vehicle's power switch is turned from on to off, and / or at predetermined intervals while the vehicle is running. By acquiring the usage data from the downstream ECU, the management ECU 30 measures the memory usage (measured value) of each memory included in the multiple downstream ECUs.

[0037] The management ECU 30 executes data migration in the following manner. First, the management ECU 30 determines the timing of data migration so that memory usage does not exceed the upper limit of memory capacity. A memory usage threshold (hereinafter also referred to as the "memory usage threshold") is set for downstream memory. The memory usage threshold is set to a value lower than the upper limit of memory capacity. The memory usage threshold may be set to a different value for each memory contained in multiple downstream memory, or it may be the same value. The management ECU 30 determines the timing of data migration to be when memory usage exceeds the memory usage threshold.

[0038] Furthermore, if the management ECU 30 is monitoring the memory usage of the downstream memory by predicting the memory usage of the downstream memory, it may predict the point in time when the memory usage will exceed the memory usage threshold and determine the predicted point in time as the timing for executing data migration.

[0039] When the determined data migration execution timing is reached, the management ECU 30 sends a migration command to the downstream ECU to execute the data migration. The management ECU 30 may specify the data to be migrated, or the amount of data to be migrated, in the migration command. For example, the management ECU 30 specifies the data to be migrated by the ID assigned to the vehicle data. When the downstream ECU receives the migration command from the management ECU 30, it identifies the vehicle data to be migrated from the downstream memory. For example, if the data to be migrated is specified by ID, the downstream ECU 30 identifies the vehicle data corresponding to the specified ID from the downstream memory. If the amount of data to be migrated is specified, the downstream ECU 30 may identify the vehicle data in order from the oldest data to be stored in the downstream memory, so that the total amount of vehicle data equals the specified amount.

[0040] The downstream ECU 30 transmits the vehicle data identified from the downstream memory to the management ECU 30. The management ECU 30 stores the vehicle data transmitted from the downstream ECU in memory 30a. After recording the vehicle data in memory 30a, the management ECU 30 transmits a completion command to the downstream ECU indicating that the data migration is complete. Upon receiving the completion command from the management ECU 30, the downstream ECU deletes the migrated vehicle data from the downstream memory. This completes the data migration.

[0041] The management ECU 30 may monitor the communication load of buses 400-402, 500-502, and 600-602 that connect the management ECU 30 to the downstream ECUs. The management ECU 30 may then perform data migration when the communication load is below a predetermined level. For example, the management ECU 30 monitors the communication load of bus 400 by measuring or predicting the communication load of bus 400. The communication load is indicated by the amount of data flowing through bus 400, the communication speed, etc. For example, the management ECU 30 may monitor the current communication load by measuring the current amount of data and / or the communication speed while transmitting and receiving data with the VCM 40 via bus 400. Alternatively, the management ECU 30 may predict the communication load from time-series data of the amount of data that has passed through bus 400 and past communication speeds.

[0042] A communication load threshold (hereinafter also referred to as the "communication load threshold") is pre-set for buses 400-402, 500-502, and 600-602. The communication load threshold may be different or the same for each of the buses 400-402, 500-502, and 600-602. When the management ECU 30 performs data migration with the VCM 40, it performs the data migration only when the communication load of bus 400 is below the predetermined communication load threshold. Since the data migration transmits vehicle data from the downstream memory to the management ECU 30, the usage of buses 400-402, 500-502, and 600-602 increases. For example, while the vehicle is running, vehicle data acquired by the VCM 40, etc., is used not only by the VCM 40 but also by other ECUs, so buses 400-402, 500-502, and 600-602 are used for sending and receiving vehicle data. Therefore, by using the communication of buses 400-402, 500-502, and 600-602 for data updates, the management ECU 30 may perform data migration when the bus communication load is low, so as not to affect the transmission and reception of vehicle data necessary for driving. For example, when the vehicle is stopped, the amount of vehicle data transmitted and received between multiple ECUs is less than when the vehicle is in motion. Therefore, the management ECU 30 may monitor the bus communication load and perform data migration when the communication load falls below a predetermined communication load threshold.

[0043] The management ECU 30 may also identify the timing when the bus's communication load falls below a predetermined communication load threshold based on the vehicle's status, without monitoring the bus's communication load. For example, when the vehicle is stopped or parked, the amount of vehicle data transmitted and received between multiple ECUs is less than when the vehicle is in motion. Therefore, the management ECU 30 determines whether the vehicle is stopped or parked based on vehicle data such as vehicle speed, shift position, and brake operation amount. If it determines that the vehicle is stopped or parked, the management ECU 30 may then identify that the bus's communication load is below a predetermined communication load threshold.

[0044] Also, when the management ECU 30 transmits a request command to a downstream ECU so as to output usage data indicating the current memory usage amount, the request command may be transmitted in accordance with the timing when the communication load becomes equal to or less than a predetermined communication load threshold value. Thereby, the management ECU 30 can measure the memory usage amount of the downstream ECU while reducing the risk of affecting the transmission and reception of vehicle data.

[0045] Next, referring to FIG. 2, the procedure of the ECU control method of the present embodiment will be described. FIG. 2 is a flowchart showing a control flow executed by the management ECU 30.

[0046] In step S1, the management ECU 30 monitors the memory usage amount of the downstream memory included in the downstream ECU. In step S2, the management ECU 30 determines whether the memory usage amount is greater than the memory usage threshold value. If the memory usage amount is equal to or less than the memory usage threshold value, the control flow returns to step S1. If the memory usage amount is greater than the memory usage threshold value, in step S3, the management ECU 30 monitors the communication load of the bus.

[0047] In step S4, the management ECU 30 determines the timing when the communication load becomes equal to or less than a predetermined communication load threshold value as the execution timing of data transfer. In step S5, the management ECU 30 determines whether the current time has reached the execution timing of data transfer. If the current time has not reached the execution timing of data transfer, the control flow waits at step S5.

[0048] If the current time has reached the execution timing of data transfer, the management ECU 30 transmits a data transfer command to the downstream ECU that is the target of data transfer (step S6). Then, data transfer is started. In step S7, the management ECU 30 determines whether data transfer has been completed. If data transfer has not been completed, the control flow waits at step S7.

[0049] If the data migration is complete, in step S8, the management ECU 30 sends a completion command to the downstream ECU indicating that the data migration is complete. Upon receiving the completion command from the management ECU 30, the downstream ECU deletes the migrated vehicle data from the downstream memory. This ensures that the management ECU 30 executes the data before the memory usage of the downstream memory exceeds its upper limit.

[0050] The management ECU 30 does not need to perform all the steps shown in Figure 2; it may omit some steps, and the execution order of the steps may be changed. For example, step S3 may be omitted, and the management ECU 30 may determine the timing for executing the data migration as the timing when the predicted or measured value of memory usage becomes greater than the memory usage threshold (step S4), and then execute the control flow from step S5 onward. Alternatively, the management ECU 30 may execute the control flow of step S3 before step S1.

[0051] As described above, in this embodiment, the management ECU 30 monitors the memory usage of the downstream memory and performs data migration to transfer vehicle data stored in the downstream memory to the management ECU before the memory usage exceeds the upper limit of the downstream memory. The downstream ECU also deletes the vehicle data that has been migrated to the management ECU 30 from the downstream memory. This ensures that vehicle data can be migrated from the downstream ECU to the management ECU 30 before the memory usage of the downstream ECU exceeds the upper limit of the memory. Furthermore, the downstream ECU can free up memory by deleting unnecessary vehicle data from the downstream memory. In addition, because the management ECU 30 monitors the memory usage of the downstream memory and performs data migration as appropriate, it avoids using memory with unnecessarily large capacity in the downstream memory and minimizes the required capacity of the downstream memory. Moreover, it is possible to manage the memory usage of the downstream memory while maintaining a margin for the downstream memory.

[0052] In this embodiment, the management ECU 30 monitors the communication load of buses 400-402, 500-502, and 600-602 connecting the management ECU 30 to the downstream ECUs, and performs data migration when the communication load is below a predetermined communication load threshold. This makes it possible to measure the memory usage of the downstream ECUs while minimizing the risk of affecting the transmission and reception of vehicle data, for example, while the vehicle is in motion.

[0053] 1 Server 10 Communication Unit 20 OBD Terminal 30 Management ECU 30a Memory 40 VCM 40a Memory 50 ADCU 50a Memory 60 BCM 60a Memory 100 ECU Control System 400-402, 500-502, 600-602 Bus

Claims

1. An ECU control system installed in a vehicle, comprising a management ECU and a plurality of downstream ECUs connected downstream of the management ECU, wherein the downstream ECUs have downstream memory for storing vehicle data, the management ECU monitors the memory usage of the downstream memory, and before the memory usage exceeds the upper limit capacity of the downstream memory, performs data migration to transfer the vehicle data stored in the downstream memory from the downstream memory to the management ECU, and the downstream ECUs delete the vehicle data transferred to the management ECU from the downstream memory.

2. An ECU control system according to claim 1, wherein the management ECU predicts the amount of memory usage based on at least one of the following: the driving history of the vehicle's driver, the operation history of the in-vehicle equipment, the update history of the software included in the downstream ECU, and the usage history of the downstream memory.

3. An ECU control system according to claim 1 or 2, wherein the management ECU sends a request command to the downstream ECU to output usage data indicating the current memory usage, and the downstream ECU sends the usage data to the management ECU in response to the request command.

4. An ECU control system according to any one of claims 1 to 3, wherein the management ECU monitors the communication load of the bus connecting the management ECU and the downstream ECU, and performs the data migration when the communication load is less than or equal to a predetermined communication load threshold.

5. An ECU control method performed by a management ECU and a downstream ECU installed in a vehicle, wherein the management ECU monitors the memory usage of the downstream memory included in the downstream ECU, and before the memory usage exceeds the upper limit capacity of the downstream memory, it performs a data migration to move vehicle data stored in the downstream memory from the downstream memory to the management ECU, and the downstream ECU deletes the vehicle data that has been moved to the management ECU from the downstream memory.

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