In-vehicle network system and control method for an in-vehicle network system

Abstract

The power supply to the lower-level control device, which receives power via a relay circuit, should be cut off at an appropriate time. [Solution] The intermediate ECUs 20 and 30 have relay control units 24 and 34 that turn on or off relay circuits 26, 28, and 36 provided on the power supply lines 6 of the lower ECUs 40, 50, and 60. The relay control units turn on or off the relay circuits according to vehicle status information relating to the state of the vehicle. The lower ECUs are able to perform control processing and termination processing by being supplied with power via the relay circuits, and periodically send periodic messages while performing control processing and termination processing. The relay control units keep the relay circuits on as long as periodic messages are being sent from the lower ECUs, even if the vehicle status information changes to switch the relay circuits from on to off.

Description

Technical Field

[0001] The present disclosure relates to an in-vehicle network system having a plurality of control devices connected to a communication bus and capable of communicating with each other in a vehicle, and a control method for the in-vehicle network system.

Background Art

[0002] For example, Patent Document 1 discloses an in-vehicle device capable of cutting off power supply from a power supply device to an in-vehicle ECU that does not require startup. The in-vehicle device is communicably connected to a plurality of in-vehicle ECUs. The in-vehicle device acquires information regarding the in-vehicle ECU to be started via an in-vehicle network. Then, the in-vehicle device supplies power to the in-vehicle ECU to be started and outputs a startup signal via the in-vehicle network in a state where power supply to the in-vehicle ECU that does not require startup is cut off. As a result, only the in-vehicle ECU to be started is started by the startup signal, and startup of the in-vehicle ECU that does not require startup is avoided.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the system of Patent Document 1 described above, no consideration is given to stopping power supply to the started in-vehicle ECU. For example, assume a case where the in-vehicle device starts one or more in-vehicle ECUs based on information regarding the in-vehicle ECU to be started acquired in the past, but the in-vehicle ECU in question is out of the startup target according to the information regarding the in-vehicle ECU to be started acquired later. In this case, the in-vehicle device will cut off power supply to the corresponding in-vehicle ECU based on the information regarding the in-vehicle ECU to be started acquired later.

[0005] However, cutting off power to the vehicle's ECU without considering its current state could lead to various problems. For example, if the power supply to the vehicle's ECU is cut off while it is still performing processing to fulfill a specific function, that function will be interrupted. Also, if the processing to fulfill a specific function has finished, but the vehicle's ECU is performing termination processing, including backing up data such as processing progress and learning results, cutting off power to the vehicle's ECU could prevent the necessary data from being saved.

[0006] This disclosure has been made in view of the above-mentioned points, and aims to provide an in-vehicle network system and a control method for an in-vehicle network system that can interrupt the power supply to a lower-level control device, which is powered via a relay circuit, at an appropriate timing. [Means for solving the problem]

[0007] To achieve the above objective, the in-vehicle network system according to this disclosure is an in-vehicle network system (100) having a plurality of control devices (10, 20, 30, 40, 50, 60) connected to a communication bus (38, 44, 54, 64) in a vehicle and capable of communicating with each other, Multiple control devices include at least one lower control device (40, 50, 60) and at least one higher control device (20, 30) positioned above the lower control device. The upper-level control unit has relay control units (24, 34) that turn on or off relay circuits (26, 28, 36) provided on the power supply line (6) of the lower-level control unit. The relay control unit turns the relay circuit on or off according to vehicle status information regarding the vehicle's condition. The lower-level control unit is powered via a relay circuit, enabling it to perform predetermined processes, and while performing these processes, it periodically transmits periodic messages. The relay control unit is configured to keep the relay circuit on even when the vehicle status information changes to switch the relay circuit from on to off, as long as a periodic message is being sent from the lower-level control unit.

[0008] Furthermore, the control method for an in-vehicle network system according to this disclosure is a control method for an in-vehicle network system (100) having a plurality of control devices (10, 20, 30, 40, 50, 60) connected to a communication bus (38, 44, 54, 64) in a vehicle and capable of communicating with each other, Multiple control devices include at least one lower control device (40, 50, 60) and at least one higher control device (20, 30) positioned above the lower control device. The upper-level control unit has relay control units (24, 34) that turn on and off relay circuits (26, 28, 36) provided on the power supply line (6) of the lower-level control unit. The relay control unit turns the relay circuit on or off according to vehicle status information regarding the vehicle's condition. A lower-level control unit, which has become capable of performing a predetermined process by receiving power through a relay circuit, periodically transmits a periodic message while performing the predetermined process, and The relay control unit is configured to keep the relay circuit on even if the vehicle status information changes to switch the relay circuit from on to off, as long as a periodic message is being sent from the lower-level control unit.

[0009] In the in-vehicle network system and control method for the in-vehicle network system described herein, the relay control unit of the higher-level control unit keeps the relay circuit ON as long as a periodic message is being transmitted from the lower-level control unit, even if the vehicle status information changes to switch the relay circuit from ON to OFF as described above.

[0010] Therefore, according to the in-vehicle network system and control method for the in-vehicle network system described herein, it is possible to avoid the interruption of power supply to a lower-level control unit while the lower-level control unit is performing a predetermined process. In other words, the lower-level control unit can interrupt power supply to the lower-level control unit at an appropriate timing after the predetermined process is completed.

[0011] The reference numbers in parentheses above are merely examples of correspondences with specific configurations in embodiments described later, in order to facilitate understanding of this disclosure, and are not intended to limit the scope of this disclosure in any way.

[0012] Furthermore, technical features described in each claim of the patent claims, other than those described above, will become clear from the description of the embodiments and the accompanying drawings, which will be discussed later. [Brief explanation of the drawing]

[0013] [Figure 1] This is a configuration diagram showing an example of the configuration of an in-vehicle network system according to the first embodiment. [Figure 2] This is a sequence diagram showing the case where the first and second intermediate ECUs turn off the first to third relay circuits based solely on vehicle status information. [Figure 3] This is a sequence diagram showing when the first and second intermediate ECUs turn off the first to third relay circuits based not only on vehicle status information but also on periodic messages sent periodically from the first to third lower ECUs. [Figure 4] This flowchart shows an example of a process performed in the upper ECU, the first and second intermediate ECUs, and the first to third lower ECUs to turn on or off the first to third relay circuits. [Figure 5] This is a configuration diagram showing an example of the configuration of an in-vehicle network system according to the second embodiment. [Figure 6]In the second embodiment, FIG. is a sequence diagram when the first and second middle ECUs turn off the first relay circuit based on vehicle state information and periodic messages periodically transmitted from the first and second lower ECUs. [Figure 7] FIG. is a configuration diagram showing an example of the configuration of an in-vehicle network system according to the third embodiment.

Embodiments for Carrying Out the Invention

[0014] Hereinafter, embodiments of an in-vehicle network system and a control method for an in-vehicle network system according to the present disclosure will be described with reference to the drawings. However, the present disclosure is not limited to the following embodiments, and various modifications described hereinafter are also included in the technical scope of the present disclosure. Furthermore, various changes can be made and implemented without departing from the gist of the present disclosure other than those described below. The embodiments and various modifications can be appropriately combined and implemented as long as there is no technical contradiction. In the following description, the same or similar configurations may be given the same reference numerals in a plurality of drawings, and the description may be omitted. Also, when only a part of the configuration is mentioned, the description described elsewhere can be applied to other parts.

[0015] (First Embodiment) FIG. 1 is a configuration diagram showing an example of the configuration of an in-vehicle network system 100 according to the present embodiment. The in-vehicle network system 100 shown in FIG. 1 includes a top ECU 10 as a top control device, first and second middle ECUs 20 and 30 as top-side control devices, and first to third lower ECUs 40, 50, and 60 as lower control devices. ECU is an abbreviation for Electronic Control Unit (electronic control device).

[0016] The in-vehicle network system 100 operates by receiving power supply from the battery 2 mounted on the vehicle. More specifically, the power from the battery 2 is provided to the upper ECU 10, the first and second middle ECUs 20, 30, and the first to third lower ECUs 40, 50, 60 of the in-vehicle network system 100 via the power supply circuit 4. The power supply circuit 4 can convert the power supply voltage of the battery 2 mounted on the vehicle into the operating voltage of the upper ECU 10, the first and second middle ECUs 20, 30, and the first to third lower ECUs 40, 50, 60 as needed. The power supply lines 6 of the first to third lower ECUs 40, 50, 60 are provided with the first to third relay circuits 26, 28, 36 whose on and off states are switched by the first and second middle ECUs 20, 30.

[0017] The configuration of the in-vehicle network system 100 is not limited to the example shown in FIG. 1. For example, the number of upper ECUs 10 may be not one but two or more. Also, the upper ECU 10 may be omitted by having any one of the middle ECUs 20, 30 also serve as the upper ECU 10. The number of middle ECUs 20, 30 may be not two but one or three or more. Regarding the lower ECUs 40, 50, 60, a plurality of lower ECUs may be connected to one relay circuit 26, 28, 36. Also, the lower ECUs 40, 50, 60 may include a lower ECU that is directly supplied with power from the power supply circuit 4 without going through the relay circuits 26, 28, 36.

[0018] The upper ECU 10, the first and second intermediate ECUs 20 and 30, and the first to third lower ECUs 40, 50, and 60 may each be composed of a computer equipped with a processor, memory, and storage. The processor is, for example, a CPU (Central Processing Unit), MPU (Micro Processing Unit), GPU (Graphics Processing Unit), or DFP (Data Flow Processor) that executes predetermined processes according to a program. Memory is a volatile storage medium that temporarily stores the results of the processor's calculations, such as RAM (Random Access Memory). Storage is a non-volatile storage medium such as flash memory or ROM (Read Only Memory). Various programs and data executed by the processor are stored in the storage.

[0019] Furthermore, backup data such as processing progress and learning results can be stored in the storage, for example, by termination processing performed by the first to third lower ECUs 40, 50, and 60 when the control processing is completed. The predetermined processing in this disclosure includes control processing and termination processing. Control processing and termination processing will be described in detail later. Note that some or all of the functions of the upper ECU 10, the first and second intermediate ECUs 20, 30, and the first to third lower ECUs 40, 50, and 60 may be implemented by hardware, such as using an ASIC (Application Specific Integrated Circuit) or an FPGA (Field-Programmable Gate Array), rather than by software such as a program.

[0020] The upper ECU 10, the first and second intermediate ECUs 20 and 30, and the first to third lower ECUs 40, 50 and 60 are further equipped with communication interfaces (communication IFs) 12, 22, 32, 42, 52 and 62 for communicating with other ECUs via communication buses 38, 44, 54 and 64.

[0021] The communication IF 12 of the upper ECU 10 is connected to the communication IFs 22 and 32 of the first and second intermediate ECUs 20 and 30 via the communication bus 38. The first and second intermediate ECUs 20 and 30 can also communicate with each other via this communication bus 38. However, the communication bus connecting the upper ECU 10 to the first and second intermediate ECUs 20 and 30 and the communication bus connecting the first and second intermediate ECUs 20 and 30 to each other may be provided separately. The communication IF 22 of the first intermediate ECU 20 is further connected to the communication IF 42 of the first lower ECU 40 via the communication bus 44. In addition, the communication IF 22 of the first intermediate ECU 20 is connected to the communication IF 52 of the second lower ECU 50 via the communication bus 54. The communication IF42 of the first lower ECU40 and the communication IF52 of the second lower ECU50 may be connected to the communication IF22 of the first intermediate ECU20 via a common communication bus. The communication IF32 of the second intermediate ECU30 is connected to the communication IF62 of the third lower ECU60 via a communication bus 64. The communication IFs22 and 32 of the first and second intermediate ECUs20 and 30 are configured to act as gateways when the upper ECU10 and the first to third lower ECUs40, 50, and 60, which are connected to different communication buses 38, 44, 54, and 64, communicate with each other.

[0022] The in-vehicle network system 100 can use CAN (registered trademark, hereinafter the same) as a communication protocol for the communication IFs 12, 22, 32, 42, 52, and 62 of the upper ECU 10, the first and second intermediate ECUs 20 and 30, and the first to third lower ECUs 40, 50, and 60 to communicate with each other. CAN is an abbreviation for Controller Area Network. However, the communication protocol is not limited to CAN, and the in-vehicle network system 100 can employ a variety of communication protocols such as Ethernet (registered trademark), LIN (Local Interconnect Network), FlexRay (registered trademark), and CAN-FD (CAN with Flexible Data Rate). For example, different communication protocols may be adopted for different communication buses 38, 44, 54, and 64.

[0023] The higher-level ECU 10 may function as a domain controller that oversees the control of the first and second intermediate ECUs 20 and 30, and the first to third lower-level ECUs 40, 50, and 60. A domain refers to a functional unit when the functions of a vehicle are broadly divided, such as a powertrain domain, chassis domain, advanced driver assistance domain, body domain, and cockpit domain. The above is just one example of domain division, and the domain division may differ from the example above. Alternatively, the higher-level ECU 10 may function as an area controller that oversees the control of the first and second intermediate ECUs 20 and 30, and the first to third lower-level ECUs 40, 50, and 60 located in each area of ​​the vehicle.

[0024] The higher-level ECU 10 has a vehicle status management unit 14 that transmits vehicle status information to the first and second intermediate ECUs 20, 30 and the first to third lower-level ECUs 40, 50, 60 based on the vehicle's status (for example, the state of driving, stopping, parking, etc., and / or the state of operation of various vehicle functions by the user) as determined from information acquired from sensors and other ECUs. The vehicle status management unit 14 may be located in other ECUs, such as the first and second intermediate ECUs 20, 30, instead of the higher-level ECU 10. Furthermore, the vehicle status management unit 14 may be distributed among multiple ECUs. In this case, the ECU receiving the vehicle status information can acquire the necessary vehicle status information by integrating or selecting multiple vehicle status information acquired from multiple ECUs.

[0025] The first and second intermediate ECUs 20 and 30 each have a first and second relay control unit 24 and 34 as a function. The first and second relay control units 24 and 34 determine which relay circuits 26, 28, and 36 to turn on and / or which relay circuits 26, 28, and 36 to keep off based on acquired vehicle status information. The first and second relay control units 24 and 34 store in advance, in the form of a table, the correspondence between various vehicle states and the relay circuits 26, 28, and 36 that supply power to the lower ECUs 40, 50, and 60 that need to operate in each vehicle state. By referring to the stored table, the first and second relay control units 24 and 34 can determine which relay circuits 26, 28, and 36 should be turned on and which should be turned off based on acquired vehicle status information.

[0026] The first intermediate ECU 20 has first and second relay circuits 26 and 28, and the second intermediate ECU 30 has a third relay circuit 36. The first relay control unit 24 of the first intermediate ECU 20 turns the first and second relay circuits 26 and 28 on or off according to the determination result based on vehicle status information. The second relay control unit 34 of the second intermediate ECU 30 also turns the third relay circuit 36 ​​on or off according to the determination result based on vehicle status information.

[0027] The first relay circuit 26 is located on the power supply line 6 for supplying power to the first lower ECU 40. In other words, the power line of the first lower ECU 40 is connected to the first power port 26a connected to the first relay circuit 26. The second relay circuit 28 is located on the power supply line 6 for supplying power to the second lower ECU 50. In other words, the power line of the second lower ECU 50 is connected to the second power port 28a connected to the second relay circuit 28. The third relay circuit 36 ​​is located on the power supply line 6 for supplying power to the third lower ECU 60. In other words, the power line of the third lower ECU 40 is connected to the third power port 36a connected to the third relay circuit 36.

[0028] The first to third relay circuits 26, 28, and 36 can be configured using semiconductor switches such as MOSFETs and IGBTs. However, the first to third relay circuits 26, 28, and 36 may also be configured using ordinary mechanical relays instead of semiconductor switches. Furthermore, the first to third relay circuits 26, 28, and 36 may be provided inside the first and second intermediate ECUs 20 and 30, as shown in Figure 1, or they may be provided outside the first and second intermediate ECUs 20 and 30.

[0029] The first to third lower ECUs 40, 50, and 60 are, for example, control ECUs for controlling a predetermined control object in a vehicle, or sensor ECUs for calculating a predetermined physical quantity based on detection signals detected by sensors. When the corresponding relay circuits 26, 28, and 36 are turned on by the first and second intermediate ECUs 20 and 30, the first to third lower ECUs 40, 50, and 60 are powered on and enter normal operation mode. In normal operation mode, the first to third lower ECUs 40, 50, and 60 perform necessary control processing, such as control processing for controlling a control object or control processing for calculating a predetermined physical quantity based on detection signals from sensors. On the other hand, when the first to third lower ECUs 40, 50, and 60 do not need to control a control object or calculate a predetermined physical quantity, and the corresponding relay circuits 26, 28, and 36 are turned off, they enter a power-off state.

[0030] The first to third lower ECUs 40, 50, and 60 can acquire vehicle status information from the higher-level ECU 10, etc., while operating in normal operating mode. Based on the acquired vehicle status information, the first to third lower ECUs 40, 50, and 60 can determine whether the vehicle has entered a state where their respective control processes are no longer necessary. When the first to third lower ECUs 40, 50, and 60 determine that the vehicle has entered a state where their respective control processes are no longer necessary, they terminate their own control processes. The first to third lower ECUs 40, 50, and 60 then execute predetermined termination processes upon the termination of their respective control processes. These predetermined termination processes include, for example, processes for saving backup data, such as backing up data from the control process, and backing up learning data if the control process involves learning.

[0031] Furthermore, the first and third lower ECUs 40, 50, and 60 periodically send periodic messages to the first and second intermediate ECUs 20 and 30 while performing the control and termination processes described above. More specifically, the first and third lower ECUs 40, 50, and 60 repeatedly send periodic messages indicating that they are operating via the communication buses 44, 54, and 64 at predetermined time intervals (i.e., transmission intervals). Therefore, the first and second intermediate ECUs 20 and 30 (i.e., the first and second relay control units 24 and 34) can determine whether the first and third lower ECUs 40, 50, and 60 are operating based on the periodic messages periodically sent from them. In the following description, the first and second intermediate ECUs 20 and 30 may be synonymous with the first and second relay control units 24 and 34.

[0032] If the first and second intermediate ECUs 20 and 30 receive a periodic message from the first to third lower ECUs 40, 50, and 60, and then receive a new periodic message from the same first to third lower ECUs 40, 50, and 60 before the periodic message transmission interval has elapsed, then the corresponding first to third lower ECUs 40, 50, and 60 can be considered to be in operation, as they are performing control processing or termination processing. On the other hand, if the first and second intermediate ECUs 20 and 30 receive a periodic message from the first to third lower ECUs 40, 50, and 60, and then, even after a period of time exceeding the periodic message transmission interval has elapsed, do not receive a new periodic message from the same first to third lower ECUs 40, 50, and 60, then the corresponding first to third lower ECUs 40, 50, and 60 can be considered to have completed control processing and termination processing, and have stopped operating.

[0033] Here, if the first and second intermediate ECUs 20 and 30 control the on / off states of the first to third relay circuits 26, 28, and 36 based solely on vehicle status information, without considering the conditions in the first to third lower ECUs 40, 50, and 60, various malfunctions may occur. An example of such a malfunction will be explained with reference to Figure 2.

[0034] As shown in the sequence diagram of Figure 2, when the first intermediate ECU 20 receives vehicle status information at times T1 and T2, it executes relay control processing. Relay control processing includes determining whether the vehicle status information corresponds to a vehicle state that turns off the first and second relay circuits 26 and 28. Furthermore, if the relay control processing determines that the vehicle state corresponds to a vehicle state that turns off the first and second relay circuits 26 and 28, it includes outputting a drive signal to turn off the first and second relay circuits 26 and 28. If it determines that the vehicle state does not correspond to a vehicle state that turns off the first and second relay circuits 26 and 28, the first and second relay circuits 26 and 28 are kept in the ON state.

[0035] The sequence diagram in Figure 2 shows an example where, at time T2, the vehicle status information received by the first intermediate ECU 20 from the upper ECU 10 corresponds to a vehicle state in which the first and second relay circuits 26 and 28 are turned off. The first intermediate ECU 20 starts relay control in response to receiving the vehicle status information at time T2. The first and second lower ECUs 40 and 50 also receive vehicle status information from the upper ECU 10 at time T2. Based on the received vehicle status information, the first and second lower ECUs 40 and 50 determine that the vehicle state does not require their own control processing. Therefore, the first and second lower ECUs 40 and 50 terminate their control processing and start predetermined termination processing.

[0036] However, when the first intermediate ECU 20 turns off the first and second relay circuits 26 and 28 through relay control processing, the first and second lower ECUs 40 and 50 may still be performing termination processing, as shown in Figure 2. If the power supply is interrupted while the first and second lower ECUs 40 and 50 are performing termination processing, it may become impossible to save necessary backup data, for example.

[0037] Therefore, in the in-vehicle network system 100 according to this embodiment, the first and second intermediate ECUs 20 and 30 determine whether to turn on or turn off the first to third relay circuits 26, 28, and 36 based not only on vehicle status information but also on periodic messages indicating that they are in operation, which are periodically transmitted from the first to third lower ECUs 40, 50, and 60.

[0038] More specifically, as illustrated in the sequence diagram of Figure 3, even if the first intermediate ECU 20 receives vehicle status information at time T2 to turn off the first and second relay circuits 26 and 28 and starts relay control, it continues to turn on the first and second relay circuits 26 and 28 while periodic messages are being sent from the first and second lower ECUs 40 and 50. The first intermediate ECU 20 monitors the periodic messages from the first and second lower ECUs 40 and 50. If the first intermediate ECU 20 does not receive a new periodic message from the first and second lower ECUs 40 and 50 after a period of time equal to or greater than the transmission interval for periodic messages has elapsed since the first intermediate ECU 20 received a periodic message from the first and second lower ECUs 40 and 50, it considers that the corresponding lower ECUs 40 and 50 have completed their control and termination processes. As illustrated in Figure 3, the first intermediate ECU 20 acquires vehicle status information to turn off the first and second relay circuits 26 and 28, and when it determines that the first and second lower ECUs 40 and 50 have completed their control and termination processes, it turns off the first and second relay circuits 26 and 28 and cuts off the power supply.

[0039] As a result, the in-vehicle network system 100 according to this embodiment makes it possible to avoid the interruption of power supply to the first to third lower ECUs 40, 50, and 60 while they are performing control processing or termination processing. In other words, the power supply to the first to third lower ECUs 40, 50, and 60 can be interrupted at an appropriate timing after the control processing and termination processing are completed.

[0040] In the example shown in Figure 3, after the termination process is completed in the first and second intermediate ECUs 20 and 30, the first and second lower ECUs 40 and 50 enter a standby state where power is supplied but processing is stopped. In this standby state, periodic messages are not sent, as shown by the dashed lines in Figure 3. Therefore, based on the fact that the periodic messages shown by the dashed lines are not sent, the first intermediate ECU 20 can understand that the first and second lower ECUs 40 and 50 have completed their control processing and termination processing.

[0041] Next, with reference to the flowchart in Figure 4, an example of the process performed in the upper ECU 10, the first and second intermediate ECUs 20 and 30, and the first to third lower ECUs 40, 50, and 60 to turn on or off the first to third relay circuits 26, 28, and 36 will be described. The upper ECU 10 and the first and second intermediate ECUs 20 and 30 repeatedly execute the process shown in the flowchart in Figure 4 at predetermined time intervals. In addition, the first and second intermediate ECUs 20 and 30 and the first to third lower ECUs 40, 50, and 60 each execute the process shown in the flowchart in Figure 4 individually. Note that the execution of the process shown in the flowchart in Figure 4 by the upper ECU 10, the first and second intermediate ECUs 20 and 30, and the first to third lower ECUs 40, 50, and 60 corresponds to the execution of the in-vehicle network system control method in this disclosure.

[0042] In step S100, the higher-level ECU 10 (vehicle status management unit 14) acquires information about the vehicle's status (for example, the status of driving, stopping, parking, etc., and / or the status of operation of various vehicle functions by the user) from sensors and other ECUs. In step S110, the higher-level ECU 10 transmits the information about the vehicle's status acquired in step S100 as vehicle status information to the first and second intermediate ECUs 20, 30 and the first to third lower-level ECUs 40, 50, 60.

[0043] In step S200, the first and second intermediate ECUs 20 and 30 receive vehicle status information from the higher-level ECU 10 and determine whether the first to third relay circuits 26, 28, and 36 are on or off based on the received vehicle status information. In step S210, the first and second intermediate ECUs 20 and 30 determine whether at least one relay circuit 26, 28, or 36 has been determined to be on in the determination process of step S200. If it is determined that at least one relay circuit 26, 28, or 36 has been determined to be on, the first and second intermediate ECUs 20 and 30 proceed to the process of step S230. On the other hand, if it is determined that at least one relay circuit 26, 28, or 36 has not been determined to be on, the first and second intermediate ECUs 20 and 30 proceed to the process of step S240.

[0044] In step S230, the first and second intermediate ECUs 20 and 30 output drive signals to turn on the corresponding relay circuits 26, 28, and 36 that have been determined to be ON. This supplies power to the first to third lower ECUs 40, 50, and 60 connected to the turned-on relay circuits 26, 28, and 36.

[0045] In step S240, the first and second intermediate ECUs 20 and 30 determine whether or not an OFF determination was made for at least one relay circuit 26, 28, and 36 in the determination process of step S200. If it is determined that an OFF determination was made for at least one relay circuit 26, 28, and 36, the first and second intermediate ECUs 20 and 30 proceed to the process of step S250. On the other hand, if it is determined that an OFF determination was not made for at least one relay circuit 26, 28, and 36, the first and second intermediate ECUs 20 and 30 terminate the process shown in the flowchart of Figure 4.

[0046] In step S250, the first and second intermediate ECUs 20 and 30 determine whether they have received a new periodic message from the first to third lower ECUs 40, 50, and 60 before the periodic message transmission interval has elapsed. If they determine that they have received a new periodic message, the corresponding first to third lower ECUs 40, 50, and 60 are performing control processing or termination processing. Therefore, the first and second intermediate ECUs 20 and 30 repeatedly execute the process in step S250 until they no longer receive new periodic messages from the first to third lower ECUs 40, 50, and 60, in other words, until the first to third lower ECUs 40, 50, and 60 stop operating. On the other hand, if the first and second intermediate ECUs 20 and 30 determine in step S250 that they have not received a new periodic message before the periodic message transmission interval has elapsed, they proceed to the process in step S260.

[0047] In step S260, the first and second intermediate ECUs 20 and 30 turn off the first to third relay circuits 26, 28, and 36 corresponding to the first to third lower ECUs 40, 50, and 60 that do not receive periodic messages. This cuts off the power supply to the first to third lower ECUs 40, 50, and 60 that are connected to the turned-off relay circuits 26, 28, and 36.

[0048] In step S300, the first to third lower ECUs 40, 50, and 60, which have been powered, start up and enter normal operating mode. In step S310, the first to third lower ECUs 40, 50, and 60, which are in normal operating mode, execute necessary control processes, such as control processes for controlling the controlled object and control processes for calculating predetermined physical quantities based on sensor detection signals.

[0049] In step S320, the first to third lower ECUs 40, 50, and 60, which are operating in normal operation mode, receive vehicle status information from the higher ECU 10 and determine whether the vehicle is in a state where their own control processing is unnecessary based on the received vehicle status information. That is, the first to third lower ECUs 40, 50, and 60 determine whether they should terminate their own control processing based on the vehicle status information. In step S330, the first to third lower ECUs 40, 50, and 60 determine whether the result of the determination in step S320 is the end of the control processing. If the determination result is not the end of the control processing, the first to third lower ECUs 40, 50, and 60 proceed to the process in step S340. On the other hand, if the determination result is the end of the control processing, the first to third lower ECUs 40, 50, and 60 proceed to the process in step S350.

[0050] In step S340, the first to third lower ECUs 40, 50, and 60 perform the process of sending periodic messages at predetermined transmission intervals. After that, the first to third lower ECUs 40, 50, and 60 return to the process of step S310.

[0051] In step S350, the first to third lower ECUs 40, 50, and 60 perform predetermined termination processes. These predetermined termination processes include saving backup data, such as backing up data from the control process and backing up learning data if the control process involves learning. In step S360, the first to third lower ECUs 40, 50, and 60 perform a process to send periodic messages at predetermined transmission intervals. Thus, the first to third lower ECUs 40, 50, and 60 continue to send periodic messages even while performing predetermined termination processes.

[0052] In step S370, the first to third lower ECUs 40, 50, and 60 determine whether a predetermined termination process has been completed. If they determine that the predetermined termination process has not been completed, the first to third lower ECUs 40, 50, and 60 return to the process in step S350. On the other hand, if they determine that the predetermined termination process has been completed, the first to third lower ECUs 40, 50, and 60 proceed to the process in step S380. At this point, since the first to third lower ECUs 40, 50, and 60 have completed the predetermined termination process, they are in a standby state where power is supplied but processing is stopped. In step S380, the corresponding relay circuits 26, 28, and 36 are turned off, causing the first to third lower ECUs 40, 50, and 60 to transition from the standby state to a power-off state.

[0053] As described above, in the in-vehicle network system 100 according to this embodiment, the first and second intermediate ECUs 20 and 30 keep the first to third relay circuits 26, 28, and 36 on while periodic messages are being transmitted from the first to third lower ECUs 40, 50, and 60, even if the vehicle status information changes to the point where at least one of the first to third relay circuits 26, 28, and 36 switches from on to off. As a result, the in-vehicle network system 100 according to this embodiment makes it possible to avoid the interruption of power supply to the first to third lower ECUs 40, 50, and 60 while they are performing control processing or termination processing. Therefore, the first and second intermediate ECUs 20 and 30 can cut off power supply to the first to third lower ECUs 40, 50, and 60 at an appropriate timing after the control processing and termination processing in the first to third lower ECUs 40, 50, and 60 are completed.

[0054] (Second Embodiment) Next, a second embodiment of the in-vehicle network system and control method for the in-vehicle network system according to this disclosure will be described. The in-vehicle network system 100A according to this embodiment is configured in much the same way as the in-vehicle network system 100 according to the first embodiment. Therefore, the same configuration as the in-vehicle network system 100 according to the first embodiment will be omitted from the description by assigning the same reference numerals.

[0055] Figure 5 is a configuration diagram showing an example of the configuration of the in-vehicle network system 100A according to the second embodiment. As shown in Figure 5, in the in-vehicle network system 100A according to this embodiment, the first and second lower ECUs 40a and 50a are connected to the first relay circuit 26, which controls the on / off state of the first intermediate ECU 20. However, the number of lower ECUs connected to the first relay circuit 26 is not limited to two, and three or more lower ECUs may be connected.

[0056] Thus, when multiple lower ECUs (first and second lower ECUs 40a and 50a) are connected to a single first relay circuit 26, the first relay control unit 24 of the first intermediate ECU 20 needs to consider the processing status of the multiple lower ECUs (first and second lower ECUs 40a and 50a) and turn off the first relay circuit 26.

[0057] In this regard, in the in-vehicle network system 100A according to this embodiment, as shown in the sequence diagram of Figure 6, the first intermediate ECU 20 (first relay control unit 24) is configured not to turn off the first relay circuit 26 if only periodic messages from any of the lower ECUs (first lower ECU 40a or second lower ECU 50a) are interrupted, but to turn off the first relay circuit 26 only when periodic messages from all of the lower ECUs (first lower ECU 40a or second lower ECU 50a) have been interrupted.

[0058] For example, in the example shown in the sequence diagram of Figure 6, at time T2, the higher-level ECU 10 transmits vehicle status information indicating that control processing by the first lower-level ECU 40a is not required, but control processing by the second lower-level ECU 50a is required. Upon receiving this vehicle status information, the first lower-level ECU 40a terminates its control processing and starts a predetermined termination process. On the other hand, the second lower-level ECU 50a continues its control processing because the vehicle status information indicates that control processing by the second lower-level ECU 50a is required. The vehicle status information transmitted from the higher-level ECU 10 at time T2 is also received by the first intermediate-level ECU 20. Based on the received vehicle status information, the first intermediate-level ECU 20 determines to turn off the relay circuit 26 corresponding to the first lower-level ECU 40a and turn on the relay circuit corresponding to the second lower-level ECU 50a.

[0059] At time T3, the second lower ECU 50a receives vehicle status information from the upper ECU 10 indicating a vehicle state in which control processing by the second lower ECU 50a is no longer required. Upon receiving this vehicle status information, the second lower ECU 50a terminates its control processing and begins predetermined termination processing. Thus, the timing at which the first lower ECU 40a and the second lower ECU 50a terminate their respective control processing may differ. In addition, the vehicle status information transmitted from the upper ECU 10 at time T3 is also received by the first intermediate ECU 20. Based on the received vehicle status information, the first intermediate ECU 20 determines to turn off the relay circuit 26 corresponding to the second lower ECU 50a.

[0060] For example, if the first and second lower ECUs 40a and 50a complete their respective control processes at different times, even if the first lower ECU 40a completes its predetermined termination process and stops sending periodic messages as shown by the dashed arrow in Figure 6, the second lower ECU 50a, which is still performing its predetermined termination process, may still send periodic messages. In this case, the first intermediate ECU 20 maintains the first relay circuit 26 ON because the second lower ECU 50a is still operating.

[0061] Subsequently, the first intermediate ECU 20, in response to determining that the transmission of periodic messages from the second lower ECU 50a has stopped, as shown by the dashed-dotted arrow in Figure 6, turns off the first relay circuit 26 and cuts off the power supply to the first and second lower ECUs 40a and 50a.

[0062] Thus, according to the in-vehicle network system 100A of this embodiment, even if the vehicle status information changes to switch the first relay circuit 26 from on to off, the first intermediate ECU 20 keeps the first relay circuit 26 on as long as a periodic message is being sent from at least one of the multiple first and second lower ECUs 40a, 50a, specifically the lower ECU 50a. As a result, according to the in-vehicle network system 100A of this embodiment, it is possible to avoid turning off the relay circuit 26 while at least one of the multiple lower ECUs 40a, 50a connected to a single relay circuit 26 is performing control processing or termination processing.

[0063] In the example described above, the termination times of the termination processes of multiple lower-level ECUs 40a and 50a differed because their respective control processes terminated at different times. However, the factors causing these differences in termination times are not limited to differences in the termination times of control processes. For example, the time required for each termination process executed by multiple lower-level ECUs 40a and 50a may differ. In this case as well, the termination times of the termination processes of the multiple lower-level ECUs 40a and 50a will differ.

[0064] (Third embodiment) Next, a third embodiment of the in-vehicle network system and the control method for the in-vehicle network system according to this disclosure will be described. The in-vehicle network system 100B according to this embodiment is configured in much the same way as the in-vehicle network system 100 according to the first embodiment. Therefore, the same configuration as the in-vehicle network system 100 according to the first embodiment will be omitted from the explanation by assigning the same reference numerals.

[0065] Figure 7 is a configuration diagram showing an example of the configuration of the in-vehicle network system 100B according to the third embodiment. As shown in Figure 7, in the in-vehicle network system 100B according to this embodiment, the upper-level ECU 10 is provided with an upper-level relay control unit 15. The first intermediate-level ECU 20 is configured to receive power via a fourth relay circuit 16, which is controlled to be on or off by the upper-level relay control unit 15. As a result, the first and second lower-level ECUs 40 and 50 receive power via the first and second relay circuits 26 and 28, as well as via the fourth relay circuit 16.

[0066] The first intermediate ECU 20 periodically transmits periodic messages to the upper ECU 10 while maintaining power supply to the first lower ECU 40 and / or the second lower ECU 50 by turning on the first relay circuit 26 and / or the second relay circuit 28. The first intermediate ECU 20 may also gateway periodic messages from the first and second lower ECUs 40 and 50 to the upper ECU 10. However, if the first and second lower ECUs 40 and 50 can communicate directly with the upper ECU 10 without going through the first intermediate ECU 20, the first intermediate ECU 20 does not need to gateway periodic messages from the first and second lower ECUs 40 and 50.

[0067] The higher-level ECU 10 (higher-level relay control unit 15) keeps the fourth relay circuit 16, which corresponds to the higher-level relay circuit, on, even if the vehicle status information changes to switch the fourth relay circuit 16, which corresponds to the higher-level relay circuit, from on to off, as long as a periodic message is being sent from the first intermediate-level ECU 20. In this case, the higher-level ECU 10 may keep the fourth relay circuit 16 on in response to receiving periodic messages from the first and second lower-level ECUs 40 and 50 in addition to the periodic messages from the first intermediate-level ECU 20. Thus, the higher-level ECU 10 may be configured to monitor periodic messages from the first and second lower-level ECUs 40 and 50 in addition to the periodic messages from the first intermediate-level ECU 20. This prevents the higher-level ECU 10 from turning off the fourth relay circuit 16 while the first and second lower-level ECUs 40 and 50 are performing control processing or termination processing.

[0068] In the third embodiment, an example was described in which relay circuits 15, 26, and 28 are provided in the upper ECU 10 and the first intermediate ECU 20, respectively, in an in-vehicle network system 100B consisting of three layers: an upper ECU 10, a first intermediate ECU 20, and first and second lower ECUs 40 and 50. However, the layers of the in-vehicle network system are not limited to three layers, but may be four or more layers. When the in-vehicle network system 100B has four or more layers, relay circuits that turn on or off the power supply to the lower layer's ECU may be provided in the ECU of each layer except the lowest layer.

[0069] Furthermore, in the in-vehicle network system 100B according to the third embodiment, the second intermediate ECU 30 is omitted. The third lower ECU 60 is configured to receive power via a fifth relay circuit 17, which is switched on and off by the upper relay control unit 15 of the upper ECU 10. In this way, the upper ECU 10 may be configured to directly control whether or not power is supplied to the lower ECU 60.

[0070] (modified version) While preferred embodiments of this disclosure have been described above, this disclosure is not limited in any way to the embodiments described above and can be implemented in various modified forms without departing from the spirit of this disclosure.

[0071] (Variation 1) For example, in the first to third embodiments described above, the periodic messages transmitted by the first to third lower ECUs 40, 50, and 60 may be network management (NM) messages. An NM message is a message used to realize so-called partial networking and includes, for example, an identifier indicating the source ECU and startup cluster information indicating the group of ECUs to operate.

[0072] When partial networking is implemented using NM messages, each ECU belonging to the in-vehicle network systems 100, 100A, and 100B is assigned to a cluster within a group of divided clusters. The assigned cluster is then stored in each ECU as cluster configuration information. When an NM message is sent from an ECU, the ECUs belonging to the cluster requested to be started up by the startup cluster information contained in that NM message start up and enter normal operation mode, while the other ECUs remain in sleep mode.

[0073] As described above, NM messages can include an identifier indicating the source ECU, and therefore can be used as periodic messages in this disclosure.

[0074] (Modification 2) The systems and methods described in this disclosure may be implemented by a dedicated computer comprising a processor programmed to perform one or more functions embodied by a computer program. The systems and methods described in this disclosure may be implemented using dedicated hardware logic circuits. The systems and methods described in this disclosure may be implemented by one or more dedicated computers comprising a combination of a processor that executes a computer program and one or more hardware logic circuits. For example, some or all of the functions of the upper ECU 10, the first and second intermediate ECUs 20, 30, and the first to third lower ECUs 40, 50, 60 may be implemented as hardware. Embodiments of implementing a certain function as hardware include embodiments using one or more ICs, etc. Some or all of the functions of the upper ECU 10, the first and second intermediate ECUs 20 and 30, and the first to third lower ECUs 40, 50, and 60 may be implemented using a system-on-a-chip (SoC), integrated circuit (IC), or field-programmable gate array (FPGA). The concept of IC also includes application-specific integrated circuits (ASIC). Furthermore, computer programs only need to be stored on a computer-readable non-transitory tangible storage medium as instructions executed by the computer. Hard disk drives (HDDs), solid state drives (SSDs), flash memory, etc., can be used as the storage medium for programs. Furthermore, the scope of this disclosure also includes programs for causing a computer to function as a higher-level ECU 10, first and second intermediate-level ECUs 20 and 30, and first to third lower-level ECUs 40, 50 and 60, as well as non-transitional physical recording media such as semiconductor memory on which these programs are recorded.

[0075] (Disclosure of technical ideas) Finally, this specification discloses several technical concepts described in the following sections. Some sections may be written in a polynomial form, selectively referencing several preceding sections. Furthermore, some sections may be written in a multiple polynomial form, referencing several sections, including other sections in a polynomial form. These sections written in polynomial and multiple polynomial forms define several technical concepts. Furthermore, the several technical concepts described in the following sections also apply to methods for controlling in-vehicle network systems.

[0076] (Technical thought 1) An in-vehicle network system (100) in a vehicle having multiple control devices (10, 20, 30, 40, 50, 60) connected to a communication bus (38, 44, 54, 64) and capable of communicating with each other, The multiple control devices include at least one lower control device (40, 50, 60) and at least one higher control device (20, 30) positioned above the lower control device. The upper-level control device has relay control units (24, 34) that turn on or off relay circuits (26, 28, 36) provided in the power supply line (6) of the lower-level control device. The relay control unit turns the relay circuit on or off according to vehicle status information relating to the state of the vehicle. The aforementioned lower-level control device is powered via the relay circuit, enabling it to perform predetermined processing, and periodically transmits periodic messages while performing the predetermined processing. An in-vehicle network system in which the relay control unit keeps the relay circuit on even when the vehicle status information changes to switch the relay circuit from on to off, as long as the periodic message is being transmitted from the lower-level control unit.

[0077] (Technical thought 2) The in-vehicle network system according to Technical Concept 1, wherein if the relay control unit does not receive a new periodic message from the lower-level control unit even after a period of time equal to or greater than the transmission interval for the periodic messages has elapsed since the relay control unit received the periodic message from the lower-level control unit, the lower-level control unit considers that it has completed the predetermined processing.

[0078] (Technical Thought 3) The in-vehicle network system according to technical concept 2, wherein the relay control unit turns off the relay circuit in response to the vehicle status information changing to switch the relay circuit from on to off, and the lower-level control unit deeming that it has completed the predetermined process.

[0079] (Technical Thought 4) At least two of the lower-level control devices (40a, 50a) are connected to the power supply line on which the relay circuit is provided. An in-vehicle network system according to any one of technical ideas 1 to 3, wherein the relay control unit keeps the relay circuit on even when the vehicle status information changes to switch the relay circuit from on to off, as long as the periodic message is transmitted from at least one of the at least two lower-level control devices.

[0080] (Technical Thought 5) At least two of the aforementioned lower control devices each initiate or terminate the predetermined processing according to the vehicle status information, and at least two of the aforementioned lower control devices each, upon terminating the predetermined processing, stop transmitting the periodic message after performing termination processing. The in-vehicle network system according to technical concept 4, wherein at least two of the lower-level control devices have different times required for the termination process.

[0081] (Technical Thought 6) The in-vehicle network system has a higher-level control device (10) positioned above the higher-level control device, An in-vehicle network system according to any one of technical concepts 1 to 5, wherein at least two or more of the above-level control devices are provided below the above-level control device.

[0082] (Technical Thought 7) The above-level control device provides the above-level control device with at least a portion of the vehicle status information, as described in technical concept 6, for the in-vehicle network system.

[0083] (Technical Thought 8) The above-level control device has an above-level relay control unit (15) that turns on or off an above-level relay circuit (16) provided on at least one of the above-level control devices' power supply lines (6), At least one of the higher-level control devices periodically sends periodic messages to the higher-level control device, The in-vehicle network system according to technical concept 6 or 7, wherein the higher-level relay control unit keeps the higher-level relay circuit on while the periodic message is being transmitted from at least one of the higher-level control devices, even if the vehicle status information changes to switch the higher-level relay circuit from on to off.

[0084] (Technical Thought 9) The in-vehicle network system according to technical concept 8, wherein the higher-level control device periodically transmits the periodic message to the higher-level control device while maintaining power supply to the lower-level control device by turning on the relay circuit. [Explanation of Symbols]

[0085] 2: Battery, 4: Power supply circuit, 6: Power supply line, 10: Higher-level ECU, 12: Communication IF, 14: Vehicle status management unit, 15: Higher-level relay control unit, 16: 4th relay circuit, 17: 5th relay circuit, 20: 1st intermediate-level ECU, 22: Communication IF, 24: 1st relay control unit, 26: 1st relay circuit, 28: 2nd relay circuit, 30: 2nd intermediate-level ECU, 32: Communication IF, 34: 2nd relay control unit, 36: 3rd relay circuit, 38: Communication bus, 40: 1st lower-level ECU, 42: Communication IF, 44: Communication bus, 50: 2nd lower-level ECU, 52: Communication IF, 54: Communication bus, 60: 3rd lower-level ECU, 62: Communication IF, 64: Communication bus, 100: In-vehicle network system

Claims

1. An in-vehicle network system (100) in a vehicle having a plurality of control devices (10, 20, 30, 40, 50, 60) connected to a communication bus (38, 44, 54, 64) and capable of communicating with each other, The multiple control devices include at least one lower-level control device (40, 50, 60) and at least one higher-level control device (20, 30) positioned above the lower-level control device. The upper-level control device has relay control units (24, 34) that turn on or off relay circuits (26, 28, 36) provided in the power supply line (6) of the lower-level control device. The relay control unit turns the relay circuit on or off according to vehicle status information relating to the state of the vehicle. The aforementioned lower-level control device is powered via the relay circuit, enabling it to perform predetermined processing, and periodically transmits periodic messages while performing the predetermined processing. An in-vehicle network system in which the relay control unit keeps the relay circuit on even when the vehicle status information changes to switch the relay circuit from on to off, as long as the periodic message is being transmitted from the lower-level control unit.

2. The in-vehicle network system according to claim 1, wherein if the relay control unit does not receive a new periodic message from the lower-level control unit even after a period of time equal to or greater than the transmission interval for the periodic messages has elapsed since the relay control unit received the periodic message from the lower-level control unit, the lower-level control unit deems that it has completed the predetermined processing.

3. The in-vehicle network system according to claim 2, wherein the relay control unit turns off the relay circuit in response to the vehicle status information changing to switch the relay circuit from on to off, and the lower-level control unit deeming that it has completed the predetermined process.

4. At least two of the lower control devices (40a, 50a) are connected to the power supply line on which the relay circuit is provided. The in-vehicle network system according to claim 1 or 2, wherein the relay control unit keeps the relay circuit on even when the vehicle status information changes to switch the relay circuit from on to off, as long as the periodic message is transmitted from at least one of the at least two lower-level control devices.

5. At least two of the aforementioned lower control devices each initiate or terminate the predetermined processing according to the vehicle status information, and at least two of the aforementioned lower control devices each, upon terminating the predetermined processing, stop transmitting the periodic message after performing termination processing. The in-vehicle network system according to claim 4, wherein at least two of the lower-level control devices have different times required for the termination process.

6. The in-vehicle network system has a higher-level control device (10) which is positioned even higher than the higher-level control device, The in-vehicle network system according to claim 1 or 2, wherein at least two or more of the above-level control devices are provided below the above-level control device.

7. The in-vehicle network system according to claim 6, wherein the higher-level control device provides at least a portion of the vehicle status information to the higher-level control device.

8. The above-level control device has an above-level relay control unit (15) that turns on or off an above-level relay circuit (16) provided on at least one of the above-level control devices' power supply lines (6), At least one of the higher-level control devices periodically sends periodic messages to the higher-level control device, The in-vehicle network system according to claim 6, wherein the higher-level relay control unit keeps the higher-level relay circuit on while the periodic message is transmitted from at least one of the higher-level control devices, even if the vehicle status information changes to switch the higher-level relay circuit from on to off.

9. The in-vehicle network system according to claim 8, wherein the higher-level control device periodically transmits the periodic message to the higher-level control device while maintaining power supply to the lower-level control device by turning on the relay circuit.

10. A control method for an in-vehicle network system (100) having a plurality of control devices (10, 20, 30, 40, 50, 60) connected to a communication bus (38, 44, 54, 64) and capable of communicating with each other, wherein The multiple control devices include at least one lower-level control device (40, 50, 60) and at least one higher-level control device (20, 30) positioned above the lower-level control device. The upper-level control device has relay control units (24, 34) that turn on and off relay circuits (26, 28, 36) provided in the power supply line (6) of the lower-level control device. The relay control unit turns the relay circuit on or off according to vehicle status information relating to the state of the vehicle. The lower-level control device, which has become capable of performing a predetermined process by receiving power through the relay circuit, periodically transmits a periodic message while performing the predetermined process, and A control method for an in-vehicle network system, comprising: the relay control unit keeping the relay circuit ON while the periodic message is being transmitted from the lower-level control unit, even if the vehicle status information changes to switch the relay circuit from ON to OFF.

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