In-vehicle communication system, in-vehicle device, and relay device

Abstract

This in-vehicle communication system comprises a plurality of in-vehicle devices and a relay device that relays frames transmitted and received between the in-vehicle devices. A first in-vehicle device among the in-vehicle devices transmits a frame to be transmitted to a second in-vehicle device, which is another in-vehicle device, to the relay device, the frame including first identification information enabling identification of a first communication line to which the second in-vehicle device is connected. The relay device identifies the first communication line of the transmission destination of the frame by using the first identification information included in the frame received from the first in-vehicle device.

Description

In-vehicle communication system, in-vehicle device, and relay device

[0001] This application claims priority from Japanese Patent Application No. 2024-31503, filed March 1, 2024, the disclosure of which is incorporated herein by reference in its entirety.

[0002] Patent Document 1 (JP 2018-152758 A) discloses the following technology: That is, an information management system (1) includes an on-board device (11) mounted on a vehicle and a server (12) configured to be able to communicate with the on-board device, and the on-board device includes a communication relay unit (51) configured to relay communication between a plurality of function units (32, 32a, 32n) each realizing a predetermined function based on a routing table (41), an information acquisition unit (61) configured to acquire at least one of a plurality of individual identification information corresponding to each of the plurality of function units, and a transmission unit (62) configured to transmit the at least one individual identification information acquired by the information acquisition unit to the server. The server comprises an attribute acquisition unit (24) configured to acquire individual attribute information of at least one of the functional units corresponding to the at least one individual identification information transmitted by the transmission unit, and further comprises a determination unit (62) configured to determine the parts of the routing table to be changed based on a plurality of individual attribute information corresponding to each of the plurality of functional units, including the individual attribute information of the at least one functional unit acquired by the attribute acquisition unit, and a modification unit (52) configured to modify the routing table based on the parts to be changed determined by the determination unit.

[0003] JP 2018-152758 A JP 2014-045421 A

[0004] The vehicle-mounted communication system disclosed herein comprises a plurality of vehicle-mounted devices and a relay device that relays frames transmitted and received between the vehicle-mounted devices, and a first vehicle-mounted device transmits a frame to be sent to another vehicle-mounted device, a second vehicle-mounted device, to the relay device, including first identification information that can identify a first communication line to which the second vehicle-mounted device is connected, and the relay device uses the first identification information included in the frame received from the first vehicle-mounted device to identify the first communication line to which the frame is to be sent.

[0005] One aspect of the present disclosure may be realized not only as an in-vehicle communication system including such a characteristic processing unit, but also as a method having such characteristic processing steps, or as a program for causing a computer to execute such steps. Furthermore, one aspect of the present disclosure may be realized as a semiconductor integrated circuit that realizes part or all of the in-vehicle communication system.

[0006] One aspect of the present disclosure may be realized not only as an in-vehicle device including such a characteristic processing unit, but also as a method having such characteristic processing steps, or as a program for causing a computer to execute such steps. Furthermore, one aspect of the present disclosure may be realized as a semiconductor integrated circuit that realizes part or all of the in-vehicle device.

[0007] One aspect of the present disclosure may be realized not only as a relay device including such a characteristic processing unit, but also as a method having such characteristic processing steps, or as a program for causing a computer to execute such steps. Furthermore, one aspect of the present disclosure may be realized as a semiconductor integrated circuit that realizes part or all of the relay device.

[0008] FIG. 1 is a diagram illustrating an example of the configuration of an in-vehicle communication system according to a first embodiment of the present disclosure. FIG. 2 is a diagram illustrating an example of a CAN frame transmitted by an in-vehicle device according to the first embodiment of the present disclosure. FIG. 3 is a diagram illustrating an example of the configuration of an in-vehicle ECU according to the first embodiment of the present disclosure. FIG. 4 is a diagram illustrating a portion of a CAN frame transmitted by an in-vehicle device according to the first embodiment of the present disclosure. FIG. 5 is a diagram illustrating an example of the configuration of a relay device according to the first embodiment of the present disclosure. FIG. 6 is a diagram illustrating an example of a flag table stored by the relay device according to the first embodiment of the present disclosure. FIG. 7 is a flowchart defining an example of an operation procedure when an in-vehicle ECU according to the first embodiment of the present disclosure performs a process to create a CAN frame. FIG. 8 is a flowchart defining an example of an operation procedure when a relay device according to the first embodiment of the present disclosure performs a bus identification process. FIG. 9 is a diagram illustrating an example of a sequence of relay processing in an in-vehicle communication system according to the first embodiment of the present disclosure. FIG. 10 is a diagram illustrating an example of the configuration of an in-vehicle communication system according to a second embodiment of the present disclosure. Fig. 11 is a diagram showing a portion of a CAN frame transmitted by an in-vehicle device according to the second embodiment of the present disclosure. Fig. 12 is a diagram showing an example of a flag table stored by a relay device according to the second embodiment of the present disclosure. Fig. 13 is a diagram showing another example of a flag table stored by a relay device according to the second embodiment of the present disclosure. Fig. 14 is a flowchart defining an example of an operation procedure when a relay device according to the second embodiment of the present disclosure performs bus identification processing. Fig. 15 is a diagram showing an example of a flag table stored by a modified example of a relay device according to the second embodiment of the present disclosure.

[0009] 2. Description of the Related Art Conventionally, a technique has been developed for updating a routing table used for relaying frames exchanged between in-vehicle devices in an in-vehicle network.

[0010] [Problem to be Solved by the Present Disclosure] In some cases, a vehicle of a certain model may have multiple variations in the configuration of its in-vehicle network. In this case, it is necessary to manage a routing table for each variation in the in-vehicle network configuration, which requires maintenance costs.

[0011] The present disclosure has been made to solve the above-mentioned problems, and its purpose is to provide an in-vehicle communication system, an in-vehicle device, and a relay device that can suppress increases in maintenance costs that accompany an increase in the variety of in-vehicle network configurations.

[0012] Effect of the Present Disclosure According to the present disclosure, it is possible to suppress an increase in maintenance costs that accompanies an increase in the variety of in-vehicle network configurations.

[0013] [Description of Embodiments of the Present Disclosure] First, the contents of the embodiments of the present disclosure will be listed and described. (1) An in-vehicle communication system according to an embodiment of the present disclosure includes a plurality of in-vehicle devices and a relay device that relays frames transmitted and received between the in-vehicle devices, wherein a first in-vehicle device transmits a frame addressed to a second in-vehicle device to the relay device, the frame including first identification information that can identify a first communication line to which the second in-vehicle device is connected, and the relay device uses the first identification information included in the frame received from the first in-vehicle device to identify the first communication line to which the frame is to be transmitted.

[0014] With this configuration, the relay device can identify the communication line to transmit the frame received from the in-vehicle device using the first identification information included in the frame without referring to a routing table, so that, for example, when there are multiple variations in the in-vehicle network configuration, it is not necessary to manage a routing table for each variation, thereby suppressing an increase in maintenance costs due to an increase in the variations in the in-vehicle network configuration.

[0015] (2) In (1) above, the vehicle-mounted device may communicate with a plurality of the second vehicle-mounted devices, and the plurality of second vehicle-mounted devices may each be connected to a plurality of the first communication lines, and each of the first communication lines may be assigned a priority, and the frame may further include priority information indicating the priority of the first communication line corresponding to the first identification information included in the frame.

[0016] With this configuration, in an in-vehicle communication system where there are multiple communication lines to which a frame received from an in-vehicle device can be sent, the frame can be output in order from the communication line with the highest priority, thereby allowing the frame to be relayed smoothly.

[0017] (3) In the above (2), the frame may include the first identification information, the storage location or value of which in the frame is set according to the priority.

[0018] With this configuration, the first identification information included in the frame can be used to determine the priority, so that priority control of the frame can be performed efficiently.

[0019] (4) In any of (1) to (3) above, the vehicle-mounted device may communicate with a plurality of the second vehicle-mounted devices, and the plurality of second vehicle-mounted devices may each be connected to a plurality of the first communication lines, and the relay device may include a plurality of communication ports to which the plurality of first communication lines are respectively connected, and the relay device may acquire correspondence information indicating the correspondence between the communication ports and the first identification information, and may identify the first communication line to which the frame is to be sent using the first identification information included in the frame received from the first vehicle-mounted device and the acquired correspondence information.

[0020] With this configuration, in the in-vehicle communication system, the communication line to which the frame is to be sent can be easily identified using the correspondence information.

[0021] (5) In the above (4), the in-vehicle communication system may include a plurality of the relay devices, and another relay device may be connected to at least one of the plurality of relay devices, and the second in-vehicle device may be connected to the other relay device via a second communication line, and the correspondence information may indicate a correspondence relationship between the communication port, the first identification information, and second identification information capable of identifying the second communication line.

[0022] With this configuration, in an in-vehicle communication system in which frames transmitted from an in-vehicle device are relayed through multiple relay devices, each relay device can easily identify the communication line to which the frame is to be sent using the correspondence information.

[0023] (6) In any of (1) to (5) above, the frame may further include third identification information capable of identifying a third communication line connecting the first vehicle-mounted device and the relay device, and upon receiving the frame from the vehicle-mounted device, the relay device may output a response frame to the third communication line corresponding to the third identification information included in the frame.

[0024] With this configuration, in an in-vehicle communication system that transmits a response frame corresponding to a frame received from an in-vehicle device, the destination of the response frame can be easily identified using the third identification information without, for example, referring to a table showing the correspondence between communication ports and frame senders. Furthermore, since the in-vehicle device can confirm that the frame has arrived at the relay device, the reliability of the in-vehicle communication system can be improved.

[0025] (7) An in-vehicle device according to an embodiment of the present disclosure is an in-vehicle device mounted on a vehicle and configured to transmit and receive frames with other in-vehicle devices in the vehicle via a relay device, and includes a creation unit that creates the frame including identification information that can identify the communication line to which the other in-vehicle devices are connected, and a transmission unit that transmits the frame created by the creation unit to the relay device.

[0026] With this configuration, the relay device can identify the communication line to transmit the frame received from the in-vehicle device using the first identification information included in the frame without referring to a routing table, so that, for example, when there are multiple variations in the in-vehicle network configuration, it is not necessary to manage a routing table for each variation, thereby suppressing an increase in maintenance costs due to an increase in the variations in the in-vehicle network configuration.

[0027] (8) A relay device according to an embodiment of the present disclosure is a relay device that relays frames transmitted and received between on-board devices, and includes a relay unit that receives a frame from the on-board device that is the source of the frame, the frame including identification information that can identify the communication line to which the on-board device that is the destination of the frame is connected, and a processing unit that uses the identification information included in the frame received by the relay unit to identify the communication line to which the frame is to be sent.

[0028] With this configuration, the relay device can identify the communication line to transmit the frame received from the in-vehicle device using the first identification information included in the frame without referring to a routing table, so that, for example, when there are multiple variations in the in-vehicle network configuration, it is not necessary to manage a routing table for each variation, thereby suppressing an increase in maintenance costs due to an increase in the variations in the in-vehicle network configuration.

[0029] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the drawings, identical or corresponding parts are designated by the same reference numerals, and their description will not be repeated. Furthermore, at least some of the embodiments described below may be combined in any manner.

[0030] <First embodiment> [On-vehicle communication system] Fig. 1 is a diagram illustrating an example of the configuration of an on-vehicle communication system according to a first embodiment of the present disclosure. Referring to Fig. 1, the on-vehicle communication system 301 includes, for example, one relay device 101 and multiple on-vehicle ECUs (Electronic Control Units) 202. The on-vehicle communication system 301 is mounted on a vehicle 1. The relay device 101 is used in the on-vehicle communication system 301 including multiple on-vehicle ECUs 202. The on-vehicle ECUs 202 are an example of on-vehicle devices.

[0031] In the example shown in FIG. 1, the in-vehicle communication system 301 includes the in-vehicle ECUs 202A, 202B, 202C, and 202D.

[0032] The in-vehicle communication system 301 is not limited to a configuration including four in-vehicle ECUs 202, but may be a configuration including two, three, five or more in-vehicle ECUs 202.

[0033] The in-vehicle ECU 202 is a TCU (Telematics Communication Unit), a powertrain ECU, a chassis ECU, a body ECU, etc. Note that the in-vehicle device is not limited to the in-vehicle ECU 202, and may be a sensor, a navigation device, a camera, etc.

[0034] The relay device 101 and the plurality of in-vehicle ECUs 202 constitute an in-vehicle network 401. The plurality of in-vehicle ECUs 202 are connected to the relay device 101 via a CAN (Controller Area Network) bus 51 that conforms to the CAN standard, for example.

[0035] In-vehicle ECUs 202A and 202B are connected to relay device 101 via CAN bus 51A, which is one of CAN buses 51. In-vehicle ECUs 202C and 202D are connected to relay device 101 via CAN bus 51B, which is one of CAN buses 51. CAN bus 51A is an example of a third communication line, and CAN bus 51B is an example of a first communication line.

[0036] Note that the in-vehicle communication system 301 is not limited to a configuration in which two CAN buses 51 are provided, and may be a configuration in which three or more CAN buses 51 are provided.

[0037] Furthermore, the multiple in-vehicle ECUs 202 are not limited to being connected to the relay device 101 via a CAN bus 51 that complies with the CAN standard, but may be connected to the relay device 101 via a communication line that complies with standards such as CAN FD (CAN with Flexible Data Rate), CAN XL (CAN Extra Long), and Ethernet (registered trademark).

[0038] The relay device 101 relays frames transmitted and received between a plurality of in-vehicle ECUs 202 connected to different CAN buses 51 .

[0039] For example, a detection device (not shown) is connected to each on-board ECU 202 via a cable. The detection device detects information related to the vehicle 1. The detection device is, for example, various sensors. The detection device, for example, periodically performs measurements and transmits detection data indicating the measurement results to the on-board ECU 202. In the present embodiment, as an example, one detection device is connected to one on-board ECU 202.

[0040] For example, the in-vehicle ECU 202 periodically or irregularly transmits a CAN frame including detection data received from the detection device connected to the in-vehicle ECU 202 to another in-vehicle ECU 202 .

[0041] 2 is a diagram illustrating an example of a CAN frame transmitted by an in-vehicle device according to the first embodiment of the present disclosure. Referring to Fig. 2, the CAN frame includes, in this order from the beginning of the frame, a start of frame (SOF) field, an extended identifier (ID) field, a base ID field, a remote transmission request (RTR) field, a DLC field, a data field (hereinafter also referred to as a DAT field), a cyclic redundancy check (CRC) field, an ACK field, and an end of frame (EOF) field.

[0042] [On-Vehicle ECU] Fig. 3 is a diagram illustrating an example of the configuration of an on-vehicle ECU according to the first embodiment of the present disclosure. Referring to Fig. 3, the on-vehicle ECU 202 includes a communication unit 11, a processing unit 12, and a storage unit 13. One or both of the communication unit 11 and the processing unit 12 are realized, for example, by a processing circuit including one or more processors. The storage unit 13 is, for example, a non-volatile memory included in the processing circuit. The communication unit 11 is an example of a transmission unit, and the processing unit 12 is an example of a creation unit.

[0043] When the communication unit 11 receives a CAN frame from another in-vehicle ECU 202 or the relay device 101 via the CAN bus 51 to which its own in-vehicle ECU 202 is connected, the communication unit 11 outputs the received CAN frame to the processing unit 12 .

[0044] When the processing unit 12 receives a CAN frame from the communication unit 11, it checks whether the CAN-ID of its own in-vehicle ECU 202 is included in the CAN frame.

[0045] More specifically, for example, storage unit 13 stores a reception list indicating CAN-IDs included in CAN frames that should be received by its own on-board ECU 202. The reception list is registered in storage unit 13 by the manufacturer of vehicle 1, for example, when vehicle 1 is shipped.

[0046] When the processing unit 12 receives a CAN frame from the communication unit 11, it reads out the reception list in the storage unit 13. Then, by referring to the reception list, the processing unit 12 checks whether the CAN-ID included in the CAN frame is registered in the reception list.

[0047] For example, when the processing unit 12 confirms that the CAN-ID included in a received CAN frame is registered in the reception list, the processing unit 12 performs a predetermined process based on the detection data included in the CAN frame. On the other hand, when the CAN-ID included in the received CAN frame is not registered in the reception list, the processing unit 12 discards the CAN frame.

[0048] Furthermore, the processing unit 12 creates a CAN frame whose destination is another in-vehicle ECU 202 and outputs the frame to the CAN bus 51 .

[0049] 2 and 3, for example, when processing unit 12 receives detection data from a detection device connected to its own in-vehicle ECU 202A, processing unit 12 creates a CAN frame in which the detection data is stored in the DAT field.

[0050] For example, the memory unit 13 stores a CAN-ID (hereinafter also referred to as "data ID") that indicates the type of detection data from a detection device connected to its own vehicle ECU 202A and indicates the vehicle ECU 202 that sent the CAN frame.

[0051] When the processing unit 12 creates the CAN frame, the processing unit 12 stores the data ID stored in the storage unit 13 in the base ID field of the CAN frame.

[0052] FIG. 4 is a diagram illustrating a portion of a CAN frame transmitted by the in-vehicle device according to the first embodiment of the present disclosure.

[0053] 3 and 4 , processing unit 12 includes identification information (hereinafter also referred to as “destination bus information”) that can identify CAN bus 51 in a CAN frame to be transmitted to another in-vehicle ECU 202 connected to a CAN bus 51 different from that of its own in-vehicle ECU 202, and transmits the CAN frame to relay device 101 via communication unit 11. The destination bus information is an example of first identification information.

[0054] In a CAN frame, the MSB (Most Significant Bit) of the extended ID field is flag F1, and the second bit from the MSB is flag F2. Flag F1 is a flag F that indicates whether CAN bus 51A is the destination of the CAN frame. Flag F2 is a flag F that indicates whether CAN bus 51B is the destination of the CAN frame. The initial values ​​of flags F1 and F2 are "zero." Note that flags F1 and F2 in the CAN frame may be stored in locations other than those described above.

[0055] When transmitting a CAN frame to another in-vehicle ECU 202 connected to a different CAN bus 51 than the in-vehicle ECU 202 of the processing unit 12, the processing unit 12 sets the flag in the extended ID field corresponding to the CAN bus 51 to "1." When transmitting a CAN frame to another in-vehicle ECU 202 connected to the same CAN bus 51 as the in-vehicle ECU 202 of the processing unit 12, the processing unit 12 maintains the value of each flag F in the extended ID field at its initial value.

[0056] An example will be described below in which in-vehicle ECU 202A creates a CAN frame whose destination is in-vehicle ECU 202, for example in-vehicle ECU 202C, which is connected to a CAN bus 51B different from the CAN bus 51A to which in-vehicle ECU 202A is connected.

[0057] When the processing unit 12 creates the CAN frame, it sets the flag F2 in the extension ID field to "1."

[0058] For example, the CAN frame further includes source bus information that can identify the CAN bus 51A to which the in-vehicle ECU 202A is connected. The source bus information is an example of third identification information.

[0059] More specifically, for example, in the DAT field of a CAN frame, the MSB is flag G1, and the second bit from the MSB is flag G2. Flag G1 is flag G indicating whether CAN bus 51A is the sender of the CAN frame. Flag G2 is flag G indicating whether CAN bus 51B is the sender of the CAN frame. The initial values ​​of flags G1 and G2 are "zero." Note that flags G1 and G2 in the CAN frame may be stored in locations other than those described above.

[0060] When the processing unit 12 creates the CAN frame, it sets the flag G1 in the DAT field to "1."

[0061] When the processing unit 12 sets the values ​​of the flag F2 and the flag G1 in the CAN frame to “1”, it outputs the CAN frame to the communication unit 11.

[0062] When the communication unit 11 receives a CAN frame from the processing unit 12, it outputs the CAN frame to the CAN bus 51A to which its own in-vehicle ECU 202A is connected, and stores the CAN frame in the storage unit 13 for retransmission processing, which will be described later. Furthermore, when the communication unit 11 outputs the CAN frame to the CAN bus 51, it starts a timer (not shown).

[0063] [Relay Device] Fig. 5 is a diagram illustrating an example of the configuration of a relay device according to the first embodiment of the present disclosure. Referring to Fig. 5, relay device 101 includes a plurality of communication ports 21, a relay unit 22, a processing unit 23, and a storage unit 24. One or both of relay unit 22 and processing unit 23 are realized, for example, by a processing circuit including one or more processors. Storage unit 24 is, for example, a non-volatile memory included in the processing circuit.

[0064] The communication ports 21 are terminals to which the CAN bus 51 can be connected. Each communication port 21 is connected to a corresponding in-vehicle ECU 202 via the CAN bus 51. In the example shown in Fig. 5, the relay device 101 includes communication ports 21A, 21B, and 21C, which are communication ports 21.

[0065] A unique port number is assigned to each communication port 21. In this example, the port numbers of communication ports 21A, 21B, and 21C are P1, P2, and P3, respectively.

[0066] [Description of the Problem] Relay devices are known that relay frames using a routing table that indicates the correspondence between CAN-IDs and CAN buses (hereinafter also referred to as "destination buses") to which in-vehicle ECUs to which CAN frames are to be transmitted are connected. For example, when a relay device receives a CAN frame from an in-vehicle ECU, it refers to the routing table to identify the destination bus corresponding to the CAN frame.

[0067] Here, in a certain model of vehicle 1, there may be multiple variations in the configuration of the in-vehicle network 401 depending on the drive system or destination of the vehicle 1. When the relay device 101 performs relay processing using a routing table, it is necessary to manage the routing table for each variation in the configuration of the in-vehicle network 401, which requires maintenance costs.

[0068] Therefore, the in-vehicle communication system 301 according to the embodiment of the present disclosure solves such problems by the following configuration and operation.

[0069] [Relay Device] In this embodiment, the relay device 101 identifies the CAN bus 51 to which the CAN frame received from the in-vehicle ECU 202A is to be transmitted without using a routing table.

[0070] More specifically, for example, when relay unit 22 receives a CAN frame from in-vehicle ECU 202A via CAN bus 51A, relay unit 22 outputs the received CAN frame to processing unit 23.

[0071] The processing unit 23 uses destination bus information included in the CAN frame received from the in-vehicle ECU 202A via the relay unit 22 to perform bus identification processing to identify the CAN bus 51 to which the CAN frame is to be transmitted.

[0072] When the processing unit 23 receives a CAN frame from the relay unit 22, it checks the flags F1 and F2 in the extension ID field of the CAN frame.

[0073] When the processing unit 23 confirms that the values ​​of the flags F1 and F2 in the extended ID field of the CAN frame received from the relay unit 22 are "zero," it discards the CAN frame.

[0074] The processing unit 23 performs bus identification processing when it confirms that the flag F1 or the flag F2 in the extended ID field of the CAN frame received from the relay unit 22 is "1." Here, the processing unit 23 confirms that the flag F2 is "1."

[0075] FIG. 6 is a diagram illustrating an example of a flag table stored by the relay device according to the first embodiment of the present disclosure.

[0076] 6, storage unit 24 stores a flag table Tb10 indicating the correspondence between the port number of communication port 21 and flag F. Flag table Tb10 is an example of correspondence information.

[0077] In the flag table Tb10, the flag F corresponding to the port number "P1" is "flag F1." The flag F corresponding to the port number "P2" is "flag F2." The flag F corresponding to the port number "P3" is "not applicable." The flag G shown in FIG. 6 will be described later.

[0078] 5 , when flag F2 in the extended ID field of the CAN frame received from relay unit 22 is “1,” processing unit 23 identifies port number “P2” as the port number corresponding to flag F2 by referring to flag table Tb10 in storage unit 24. Processing unit 23 then outputs port notification S1 indicating the identified port number “P2” and the CAN frame to relay unit 22.

[0079] When the relay unit 22 receives the port notification S1 and the CAN frame from the processing unit 23, it outputs the CAN frame to the CAN bus 51B connected to the communication port 21B of the port number "P2" indicated by the port notification S1.

[0080] (Response Frame) For example, when relay unit 22 receives a CAN frame from in-vehicle ECU 202A, relay unit 22 outputs the response frame to CAN bus 51 corresponding to the source bus information included in the received CAN frame.

[0081] More specifically, for example, when flag F in the extended ID field of a CAN frame received from relay unit 22 is "1," processing unit 23 checks which of flags G1 and G2 in the DAT field of the CAN frame has a value of "1." Here, processing unit 23 checks that flag G1 is "1."

[0082] The flag table Tb10 shown in FIG. 6 further indicates the correspondence between the port number of the communication port 21 and the flag G.

[0083] In the flag table Tb10, the flag G corresponding to the port number "P1" is "flag G1." The flag G corresponding to the port number "P2" is "flag G2." The flag G corresponding to the port number "P3" is "not applicable."

[0084] When the processing unit 23 confirms that the value of the flag G1 is "1", it refers to the flag table Tb10 in the storage unit 24 to identify the port number "P1" as the port number corresponding to the flag G1.

[0085] When the processing unit 23 identifies the port number corresponding to the flag G1, the processing unit 23 creates a response frame whose destination is the in-vehicle ECU 202A.

[0086] Specifically, for example, storage unit 24 further stores a response table indicating the correspondence between data IDs and CAN-IDs (hereinafter also referred to as "response IDs") to be included in the response frame. For example, the response ID indicates that the type of the CAN frame is a response frame and indicates in-vehicle ECU 202 to which the response frame is to be sent.

[0087] When the processing unit 23 identifies the port number corresponding to the flag G1, the processing unit 23 refers to the response table in the storage unit 24 to identify a response ID corresponding to the data ID included in the CAN frame received from the relay unit 22. Then, the processing unit 23 creates a response frame in which the identified response ID is stored in the base ID field.

[0088] For example, the storage unit 24 further stores an ID that can identify the relay device 101 (hereinafter, also referred to as a "relay device ID").

[0089] When the processing unit 23 creates the response frame, it stores the relay device ID stored in the storage unit 24 in the DAT field of the response frame. Then, the processing unit 23 outputs the response frame and a port notification S2 indicating the identified port number to the relay unit 22.

[0090] When the relay unit 22 receives the port notification S2 and the response frame from the processing unit 23, it outputs the response frame to the CAN bus 51A connected to the communication port 21A of the port number "P1" indicated in the port notification S2.

[0091] 3 , in in-vehicle ECU 202A, when communication unit 11 receives a CAN frame from relay device 101 via CAN bus 51A before a predetermined time has elapsed since the timer was started, communication unit 11 confirms that the response ID included in the received CAN frame is registered in the reception list by referring to the reception list in storage unit 13. In other words, communication unit 11 confirms that the CAN frame is a response frame that should be received.

[0092] Then, the communication unit 11 checks the relay device ID included in the received CAN frame, and determines that the CAN frame to be transmitted to the in-vehicle ECU 202C has arrived at the relay device 101.

[0093] On the other hand, if a response frame does not arrive from relay device 101 until a predetermined time has elapsed since starting the timer, communication unit 11 performs a retransmission process to retransmit the CAN frame to be transmitted to in-vehicle ECU 202C. Specifically, for example, communication unit 11 outputs the CAN frame stored in storage unit 13 to CAN bus 51A.

[0094] [Operation Flow] Next, a description will be given of the operation flow of the in-vehicle ECU 202 and the relay device 101 in the in-vehicle communication system 301 according to the first embodiment of the present disclosure.

[0095] 7 is a flowchart illustrating an example of an operation procedure when an in-vehicle ECU according to the first embodiment of the present disclosure performs a process of creating a CAN frame, in which the in-vehicle ECU 202A creates a CAN frame to be transmitted to the in-vehicle ECU 202C.

[0096] Referring to Figure 7, first, the in-vehicle ECU 202A waits for the arrival of detection data from the detection device connected to it (NO in step S101), and when it receives the detection data (YES in step S101), it creates a CAN frame in which the received detection data is stored in the DAT field (step S102).

[0097] Next, in-vehicle ECU 202A stores a data ID indicating the type of the detected data and indicating in-vehicle ECU 202 that is the sender of the CAN frame in the base ID field of the CAN frame (step S103).

[0098] Next, in-vehicle ECU 202A includes, in the CAN frame, destination bus information that identifies CAN bus 51B to which in-vehicle ECU 202C is connected. For example, as described above, in-vehicle ECU 202A sets flag F2, which is the second bit from the MSB, to “1” in the extended ID field of the CAN frame (step S104).

[0099] Next, in-vehicle ECU 202A includes, in the CAN frame, source bus information that identifies CAN bus 51A to which in-vehicle ECU 202A is connected. For example, as described above, in-vehicle ECU 202A sets MSB flag G1 to "1" in the DAT field of the CAN frame (step S105). Note that steps S103 to S105 may be executed in reverse order or in parallel.

[0100] Next, the in-vehicle ECU 202A outputs the CAN frame to be transmitted to the in-vehicle ECU 202C to the CAN bus 51A (step S106).

[0101] Next, if the in-vehicle ECU 202A receives a response frame from the relay device 101 before a predetermined time has elapsed since transmitting the CAN frame (YES in step S107), it determines that the CAN frame has arrived at the relay device 101 (step S108) and waits for the arrival of new detection data (NO in step S101).

[0102] On the other hand, if a response frame does not arrive from the relay device 101 even after a predetermined time has elapsed since the in-vehicle ECU 202A transmitted the CAN frame (NO in step S107), the in-vehicle ECU 202A resends the CAN frame (step S109) and waits for the arrival of a response frame (NO in step S107).

[0103] 8 is a flowchart illustrating an example of an operation procedure when the relay device 101 performs a bus identification process according to the first embodiment of the present disclosure. The flowchart illustrates a case in which the relay device 101 relays a CAN frame received from the in-vehicle ECU 202A to the in-vehicle ECU 202C.

[0104] Referring to FIG. 8, first, the relay device 101 waits for the arrival of a CAN frame (NO in step S201), and when it receives a CAN frame (YES in step S201), it checks the flags F1 and F2 in the extended ID field of the CAN frame (step S202).

[0105] If the relay device 101 determines that the flag F1 or the flag F2 is "1" (YES in step S203), the relay device 101 performs a bus identification process to identify the destination bus of the received CAN frame. Here, the relay device 101 determines that the flag F2 is "1" and identifies the CAN bus 51B as the destination bus (step S204).

[0106] Next, the relay device 101 outputs the received CAN frame to the identified destination bus, that is, the CAN bus 51B (step S205).

[0107] Next, if flag G1 or flag G2 in the received CAN frame is "1" (YES in step S206), relay device 101 outputs a response frame to CAN bus 51. Here, relay device 101 confirms that flag G1 is "1," outputs the response frame to CAN bus 51A corresponding to flag G1 (step S207), and waits for the arrival of a new CAN frame (NO in step S201).

[0108] On the other hand, if the values ​​of flag F1 and flag F2 in the received CAN frame are "zero" (NO in step S203), the relay device 101 discards the CAN frame (step S208) and waits for the arrival of a new CAN frame (NO in step S201).

[0109] Furthermore, if the flags G1 and G2 in the received CAN frame are "zero" (NO in step S206), the relay device 101 does not output a response frame and waits for the arrival of a new CAN frame (NO in step S201).

[0110] FIG. 9 is a diagram illustrating an example of a sequence of relay processing in the in-vehicle communication system according to the first embodiment of the present disclosure.

[0111] Referring to FIG. 9, first, the in-vehicle ECU 202A receives detection data from a detection device connected to the in-vehicle ECU 202A (step S301).

[0112] Next, the in-vehicle ECU 202A creates a CAN frame in which the detected data is stored in the DAT field (step S302).

[0113] Next, in-vehicle ECU 202A stores a data ID indicating the type of the detected data and indicating in-vehicle ECU 202 that is the sender of the CAN frame in the base ID field of the CAN frame (step S303).

[0114] Next, in-vehicle ECU 202A includes, in the CAN frame, destination bus information that identifies CAN bus 51B to which in-vehicle ECU 202C is connected. For example, as described above, in-vehicle ECU 202A sets flag F2, which is the second bit from the MSB, to “1” in the extended ID field of the CAN frame (step S304).

[0115] Next, in-vehicle ECU 202A includes, in the CAN frame, source bus information that identifies CAN bus 51A to which in-vehicle ECU 202A is connected. For example, as described above, in-vehicle ECU 202A sets MSB flag G1 to "1" in the DAT field of the CAN frame (step S305). Note that steps S303 to S305 may be executed in reverse order or in parallel.

[0116] Next, the in-vehicle ECU 202A transmits the CAN frame, in which the flag F2 and the flag G1 are set to "1", to the relay device 101 via the CAN bus 51A (step S306).

[0117] Next, when the relay device 101 receives the CAN frame from the in-vehicle ECU 202A, the relay device 101 checks the flags F1 and F2 in the received CAN frame. Here, the relay device 101 checks that the flag F2 in the CAN frame is set to “1” (step S307).

[0118] Next, the relay device 101 performs a bus identification process to identify the destination bus of the received CAN frame. Here, the relay device 101 identifies the CAN bus 51B as the destination bus (step S308).

[0119] Next, the relay device 101 transmits the received CAN frame to the in-vehicle ECU 202C via the identified destination bus (step S309).

[0120] Next, when the in-vehicle ECU 202C receives the CAN frame from the relay device 101, the in-vehicle ECU 202C performs a predetermined process based on the detection data included in the CAN frame (step S310).

[0121] Next, the relay device 101 confirms that the flag G1 in the CAN frame received from the in-vehicle ECU 202A is set to "1" and creates a response frame addressed to the in-vehicle ECU 202A (step S311). Note that steps S310 and S311 may be executed in reverse order or in parallel.

[0122] Next, the relay device 101 transmits the created response frame to the in-vehicle ECU 202A via the CAN bus 51A (step S312).

[0123] Next, the in-vehicle ECU 202A receives the response frame and determines that the CAN frame addressed to the in-vehicle ECU 202C has arrived at the relay device 101 (step S313).

[0124] In the in-vehicle communication system 301 according to the first embodiment of the present disclosure, the in-vehicle ECU 202A is configured to transmit a CAN frame including source bus information that identifies the CAN bus 51 to which the in-vehicle ECU 202A is connected. However, this is not limiting. The in-vehicle ECU 202A may be configured to transmit a CAN frame that does not include source bus information. In this case, the relay device 101 does not transmit a response frame to the in-vehicle ECU 202A.

[0125] Next, other embodiments of the present disclosure will be described with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference numerals and their description will not be repeated.

[0126] Second Embodiment In the above-described first embodiment of the present disclosure, one relay device 101 in the in-vehicle communication system 301 performs bus identification processing using destination bus information included in a CAN frame received from the in-vehicle ECU 202. In contrast, in the second embodiment of the present disclosure, the in-vehicle communication system 301 includes multiple relay devices 101, and each relay device 101 performs bus identification processing. Contents other than those described below are the same as those of the in-vehicle communication system 301 according to the first embodiment.

[0127] 10 is a diagram illustrating an example of a configuration of an in-vehicle communication system according to the second embodiment of the present disclosure. Referring to FIG. 10, the in-vehicle communication system 302 includes a plurality of relay devices 101 and a plurality of in-vehicle ECUs 202.

[0128] In the example shown in FIG. 10, the in-vehicle communication system 302 includes relay devices 101A and 101B, which are relay devices 101, and in-vehicle ECUs 202A to 202H, which are in-vehicle ECUs 202.

[0129] The relay device 101A is connected to the relay device 101B via a CAN bus 51C, which is a part of the CAN bus 51.

[0130] In-vehicle ECUs 202E and 202F are connected to relay device 101B via CAN bus 52A, which is a CAN bus 52 conforming to the CAN standard. In-vehicle ECUs 202G and 202H are connected to relay device 101B via CAN bus 52B, which is also a CAN bus 52. CAN bus 52 is an example of a second communication line.

[0131] The in-vehicle communication system 302 is not limited to a configuration including two relay devices 101, but may be a configuration including three or more relay devices 101.

[0132] [In-Vehicle ECU 202A] FIG. 11 is a diagram illustrating a portion of a CAN frame transmitted by an in-vehicle device according to the second embodiment of the present disclosure.

[0133] 11, for example, in a CAN frame, the MSB of the extended field is flag F1, the second bit from the MSB is flag F2, the third bit from the MSB is flag F3, the fourth bit from the MSB is flag F4, and the fifth bit from the MSB is flag F5. Note that the storage locations of flags F1 to F5 in the CAN frame may be other than those described above.

[0134] Flags F3, F4, and F5 are flags F that indicate whether CAN bus 51C, CAN bus 52A, and CAN bus 52B are destinations of the CAN frame, respectively.

[0135] For example, the MSB of the DAT field is flag G1, the second bit from the MSB is flag G2, the third bit from the MSB is flag G3, the fourth bit from the MSB is flag G4, and the fifth bit from the MSB is flag G5. The initial value of flags F1 to F5 is "zero." Note that flags G1 to G5 in the CAN frame may be stored in locations other than those described above.

[0136] Flag G3, flag G4, and flag G5 respectively indicate whether CAN bus 51C, CAN bus 52A, and CAN bus 52B are the transmission sources of CAN frames.

[0137] In this embodiment, in-vehicle ECU 202A communicates with a plurality of in-vehicle ECUs 202 that are connected to a plurality of CAN buses different from CAN bus 51A to which it is connected. An example will be described below in which in-vehicle ECU 202A creates a CAN frame to be transmitted to in-vehicle ECU 202E connected to CAN bus 52A and in-vehicle ECU 202G connected to CAN bus 52B. In this case, in-vehicle ECU 202A is an example of a first in-vehicle device, and in-vehicle ECUs 202E and 202G are examples of second in-vehicle devices.

[0138] 3, 10, and 11, for example, priorities are assigned to CAN bus 51 and CAN bus 52. A CAN frame transmitted from in-vehicle ECU 202A includes priority information indicating the priority of the CAN bus corresponding to the destination bus information included in the CAN frame.

[0139] More specifically, for example, a CAN frame transmitted from the in-vehicle ECU 202A includes destination bus information whose storage location in the CAN frame is set according to the priority of the CAN bus.

[0140] Specifically, for example, in the extended ID field of a CAN frame, a flag number is set for each flag F. The flag number is used for arbitrating communication between CAN frames. For example, the smaller the flag number value, the higher the priority.

[0141] For example, in the extended ID field, the closer the flag number of flag F is to the least significant bit (LSB), the smaller the flag number. That is, in the example shown in Fig. 11, the priority is highest in the following order: CAN bus 52B corresponding to flag F5, CAN bus 52A corresponding to flag F4, CAN bus 51C corresponding to flag F3, CAN bus 51B corresponding to flag F2, and CAN bus 51A corresponding to flag F1.

[0142] In this case, on-board ECUs 202G and 202H connected to CAN bus 52B are, for example, powertrain ECUs with an Automotive Safety Integrity Level (ASIL) level equal to or higher than a predetermined level. On-board ECUs 202E and 202F connected to CAN bus 52A are, for example, powertrain ECUs with an ASIL level equal to or higher than a predetermined level but lower than the ASIL level of on-board ECU 202 connected to CAN bus 52B. On-board ECUs 202C and 202D connected to CAN bus 51B are, for example, chassis ECUs. On-board ECUs 202A and 202B connected to CAN bus 51B are, for example, body ECUs.

[0143] Note that the CAN frame transmitted from in-vehicle ECU 202 may include destination bus information in which a CAN bus value is set according to priority, instead of a storage location in the CAN frame. Specifically, for example, in in-vehicle communication system 302, the CAN bus number may be set according to priority, and the CAN frame may include the numbers of CAN buses 51, 52, such as "1" or "2." In this case, relay device 101 outputs the CAN frames in ascending or descending order of the numbers of CAN buses 51, 52.

[0144] When creating a CAN frame to be transmitted to the in-vehicle ECUs 202E and 202G, the processing unit 12 in the in-vehicle ECU 202A sets the flags F4 and F5 in the CAN frame to "1" and also sets the flag G1 to "1."

[0145] [Relay Device 101A] Referring back to FIG. 5, when the processing unit 23 in the relay device 101A receives a CAN frame from the relay unit 22, the processing unit 23 checks the flags F1 to F5 in the extended ID field of the CAN frame.

[0146] When the processing unit 23 confirms that the value of each of the flags F1 to F5 in the extended ID field of the CAN frame received from the relay unit 22 is "zero," it discards the CAN frame.

[0147] The processing unit 23 performs bus identification processing when it confirms that the value of at least one of the flags F1 to F5 in the extended ID field of the CAN frame received from the relay unit 22 is "1." Here, the processing unit 23 confirms that the flags F4 and F5 are "1."

[0148] 12 is a diagram illustrating an example of a flag table Tb20 stored in a relay device according to the second embodiment of the present disclosure, the flag table Tb20 being stored in the relay device 101A.

[0149] 12 , for example, flag table Tb20 indicates the correspondence between communication port 21, destination bus information, and identification information (hereinafter also referred to as “connection bus information”) that can identify CAN bus 52 connected to relay device 101B. The connection bus information is an example of second identification information.

[0150] Specifically, for example, flag table Tb20 indicates the correspondence between the port number of communication port 21, a flag F (hereinafter also referred to as "flag Fa") corresponding to CAN bus 51, and a flag F (hereinafter also referred to as "flag Fb") corresponding to CAN bus 52. That is, compared to flag table Tb10 shown in Fig. 6, flag table Tb20 further indicates flag Fb, and information corresponding to port number "P3" is registered.

[0151] In the flag table Tb20 shown in FIG. 12, the flag Fa corresponding to the port number "P3" of the communication port 21C is "Flag F3." The flag Fb corresponding to the port number "P1" of the communication port 21A is "Not Applicable." The flag Fb corresponding to the port number "P2" of the communication port 21B is "Not Applicable." The flag Fb and flag G corresponding to the port number "P3" of the communication port 21C are "Flags F4, F5" and "Flags G4, G5," respectively.

[0152] For example, the processing unit 23 performs the bus identification process using the flag table Tb20. More specifically, for example, when the processing unit 23 confirms that the flags F4 and F5 in the extended ID field of the CAN frame received from the relay unit 22 are "1," the processing unit 23 identifies the port number "P3" as the port number corresponding to the flags F4 and F5 by referring to the flag table Tb20 in the storage unit 24. Then, the processing unit 23 outputs the port notification S11 indicating the identified port number "P3" and the CAN frame to the relay unit 22.

[0153] When the relay unit 22 receives the port notification S11 and the CAN frame from the processing unit 23, it outputs the CAN frame to the CAN bus 51C connected to the communication port 21C with the port number "P3" indicated in the port notification S11.

[0154] [Relay Device 101B] (Bus Identification Process) In the relay device 101B, upon receiving a CAN frame from the relay device 101A via the CAN bus 51C, the relay unit 22 outputs the received CAN frame to the processing unit 23.

[0155] When the processing unit 23 receives a CAN frame from the relay unit 22, it confirms that the flags F4 and F5 in the extension ID field of the CAN frame are "1".

[0156] 13 is a diagram illustrating another example of a table stored in the relay device according to the second embodiment of the present disclosure, which shows a flag table Tb20 stored in the relay device 101B.

[0157] The flag table Tb20 shown in Fig. 13 differs from the flag table Tb10 shown in Fig. 6 in that the flags Fa corresponding to each port number are different and also include flags Fb. In the flag table Tb20, the flags Fa and Fb corresponding to port number "P1" are "flag F4" and "not applicable," respectively. The flags Fa and Fb corresponding to port number "P2" are "flag F5" and "not applicable," respectively. The flags Fa and Fb corresponding to port number "P3" are "flag F3" and "flags F1, F2," respectively.

[0158] 13, the flag G corresponding to the port number "P1" is "flag G4." The flag G corresponding to the port number "P2" is "flag G5." The flag G corresponding to the port number "P3" is "flag G1, G2."

[0159] When the processing unit 23 confirms that flags F4 and F5 in the CAN frame received from the relay unit 22 are "1", it refers to the flag table Tb20 in the memory unit 24 to identify port number "P1" and port number "P2" as the port number corresponding to flag F4 and the port number corresponding to flag F5, respectively.

[0160] Referring again to Figures 5 and 10, for example, if there are multiple identified port numbers, the processing unit 23 checks the port number with the highest priority according to the flag number with a value of "1" in the extended ID field of the CAN frame received from the relay unit 22.

[0161] As described above, in this case, the CAN bus 52B corresponding to the flag F5 has a higher priority than the CAN bus 52A corresponding to the flag F4.

[0162] Then, the processing unit 23 outputs to the relay unit 22 a port notification S12 indicating the identified multiple port numbers and multiple flag numbers respectively corresponding to the multiple port numbers, and the CAN frame used in the bus identification process.

[0163] When relay unit 22 receives port notification S12 and a CAN frame from processing unit 23, it outputs the CAN frame to CAN bus 52 in accordance with the multiple flag numbers indicated in port notification S12. Here, port notification S12 indicates the flag numbers of flags F4 and F5. In this case, relay unit 22 outputs the CAN frame received from processing unit 23 to CAN bus 52B corresponding to flag F5 and then to CAN bus 52A corresponding to flag F4.

[0164] On the other hand, if the number of identified port numbers is one, the processing unit 23 outputs to the relay unit 22 a port notification S13 indicating the port number and the CAN frame used in the bus identification process.

[0165] When the relay unit 22 receives the port notification S13 and the CAN frame from the processing unit 23, it outputs the CAN frame to the CAN bus 51 connected to the communication port 21 of the port number indicated in the port notification S13.

[0166] (Response Frame) When flag F in the extended ID field of a CAN frame received from relay unit 22 is "1," processing unit 23 checks which flags G, among flags G1 to G5 in the DAT field of the CAN frame, have a value of "1." Here, processing unit 23 checks that flag G1 is "1."

[0167] In the flag table Tb20 shown in Fig. 13, the flag G corresponding to the port number "P1" is "not applicable." The flag G corresponding to the port number "P2" is "not applicable." The flag G corresponding to the port number "P3" is "G1, G2."

[0168] When the processing unit 23 confirms that the value of the flag G1 is "1", it refers to the flag table Tb20 in the storage unit 24 and identifies the port number "P3" as the port number corresponding to the flag G1.

[0169] Then, the processing unit 23 creates a response frame and outputs a port notification S21 indicating the identified port number “P3” and the response frame to the relay unit 22.

[0170] When the relay unit 22 receives the port notification S21 and the response frame from the processing unit 23, it outputs the response frame to the CAN bus 51C connected to the communication port 21 with the port number "P3" indicated in the port notification S21.

[0171] [Operation Flow] Next, the operation flow of the relay device 101B in the in-vehicle communication system 301 according to the second embodiment of the present disclosure will be described.

[0172] 14 is a flowchart illustrating an example of an operation procedure when a relay device according to the second embodiment of the present disclosure performs a bus identification process. The flowchart illustrates a case in which the relay device 101B receives a CAN frame to be transmitted to the in-vehicle ECUs 202E and 202G from the in-vehicle ECU 202A via the relay device 101A.

[0173] Referring to FIG. 14, first, the relay device 101B waits for the arrival of a CAN frame (NO in step S401), and when a CAN frame is received (YES in step S401), it checks flags F1 to F5 in the CAN frame (step S402).

[0174] If the relay device 101B determines that at least one of the flags F1 to F5 in the CAN frame is set to "1" (YES in step S403), the relay device 101B performs a bus identification process to identify the destination bus of the received CAN frame. Here, the relay device 101B determines that the flags F4 and F5 are set to "1" and identifies the CAN buses 52A and 52B as the destination buses (step S404).

[0175] Next, if there are multiple identified destination buses (YES in step S405), relay device 101B checks the priority of the destination buses according to the flag number of flag F with a value of "1" in the received CAN frame. Here, relay device 101B checks that CAN bus 52B has a higher priority than CAN bus 52A (step S406).

[0176] Next, relay device 101B outputs the received CAN frame to CAN bus 52B and then to CAN bus 52A (step S407).

[0177] Next, if flag G in the received CAN frame is "1" (YES in step S408), relay device 101B outputs a response frame to CAN bus 51. Here, relay device 101 confirms that flag G1 is "1," outputs the response frame to CAN bus 51C corresponding to flag G1 (step S409), and waits for the arrival of a new CAN frame (NO in step S401).

[0178] On the other hand, if the value of each flag F in the received CAN frame is "zero" (NO in step S403), the relay device 101 discards the CAN frame (step S410) and waits for the arrival of a new CAN frame (NO in step S401).

[0179] Furthermore, if the number of identified destination buses is one (NO in step S405), the relay device 101B outputs the received CAN frame to the destination bus without checking the priority of the destination bus (step S407).

[0180] Furthermore, if the flag G in the received CAN frame is "zero" (NO in step S408), the relay device 101B does not output a response frame and waits for the arrival of a new CAN frame (NO in step S401).

[0181] In the in-vehicle communication system 302 according to the second embodiment of the present disclosure, the CAN frame transmitted from the in-vehicle ECU 202 includes priority information indicating the priority of the CAN buses 51 and 52. However, this is not limiting. The CAN frame transmitted from the in-vehicle ECU 202 may not include priority information. In this case, when the relay device 101 receives a CAN frame to be transmitted to the in-vehicle ECUs 202E and 202G from the in-vehicle ECU 202A, the relay device 101 outputs the CAN frame in a predetermined order.

[0182] In addition, in the in-vehicle communication system 302 according to the second embodiment of the present disclosure, the CAN frame transmitted from the in-vehicle ECU 202 includes destination bus information whose storage location or value in the CAN frame is set according to the priority of the CAN buses 51 and 52. However, this is not limited to this. The storage location or value of the destination bus information may not be set according to the priority. In this case, for example, the CAN frame transmitted from the in-vehicle ECU 202 includes information indicating the priority of each of the multiple pieces of destination bus information.

[0183] [Variation] In the in-vehicle communication system 302, when a plurality of in-vehicle ECUs 202 are connected to the communication port 21C of the relay device 101A via the CAN bus 51C instead of the relay device 101B, the following processing may be performed.

[0184] In this modification, a case will be described in which on-board ECUs 202E and 202F shown in Fig. 10 are connected to communication port 21C of relay device 101A via CAN bus 51C. Also, a case will be described in which on-board ECU 202A creates CAN frames to be transmitted to on-board ECUs 202C and 202E. In this case, on-board ECU 202A is an example of a first on-board device, and on-board ECUs 202C and 202E are examples of a second on-board device.

[0185] 3 and 11 again, in the in-vehicle ECU 202A, the processing unit 12 creates a CAN frame in which the flags F2 and F3 are set to "1" and the flag G1 is set to "1".

[0186] FIG. 15 is a diagram illustrating an example of a table stored in a modified example of a relay device according to the second embodiment of the present disclosure.

[0187] 15, in relay device 101A, storage unit 24 stores flag table Tb21 instead of flag table Tb20 shown in Fig. 12. In comparison with flag table Tb10 shown in Fig. 6, flag table Tb21 has registered therein information corresponding to port number "P3."

[0188] In the flag table Tb21, the flags Fa and G corresponding to the flag F3 are "flag F3" and "flag G3", respectively.

[0189] When the processing unit 23 confirms that flags F2 and F3 in the extended ID field of the CAN frame received from the relay unit 22 are "1", it refers to the flag table Tb21 in the memory unit 24 to identify port number "P2" as the port number corresponding to flag F2, and port number "P3" as the port number corresponding to flag F3.

[0190] Then, the processing unit 23 outputs to the relay unit 22 a port notification S14 indicating the identified multiple port numbers and multiple flag numbers respectively corresponding to the multiple port numbers, as well as the CAN frame used in the bus identification process.

[0191] When the relay unit 22 receives the port notification S13 and the CAN frame from the processing unit 23, it outputs the CAN frame to the CAN bus 52 in accordance with the multiple flag numbers indicated in the port notification S14. Here, the multiple flag numbers indicated in the port notification S14 are the flag numbers of flags F2 and F3. In this case, the relay unit 22 outputs the CAN frame received from the processing unit 23 to the CAN bus 51C corresponding to flag F3 and then to the CAN bus 51B corresponding to flag F2.

[0192] The above-described embodiments should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims, not by the above description, and is intended to include all modifications within the meaning and scope of the claims.

[0193] Each process (each function) in the above-described embodiments is realized by a processing circuit including one or more processors. The processing circuit may be configured as an integrated circuit or the like that combines one or more memories, various analog circuits, and various digital circuits in addition to the one or more processors. The one or more memories store programs (instructions) that cause the one or more processors to execute each of the processes. The one or more processors may execute each of the processes according to the program read from the one or more memories, or may execute each of the processes according to a logic circuit designed in advance to execute each of the processes. The processor may be any of various processors suitable for computer control, such as a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), a DSP (Digital Signal Processor), an FPGA (Field Programmable Gate Array), and an ASIC (Application Specific Integrated Circuit). Note that the physically separated processors may cooperate with each other to execute the processes. For example, the processors installed in the physically separated computers may cooperate with each other via a network such as a LAN (Local Area Network), a WAN (Wide Area Network), or the Internet to execute the processes. The program may be installed into the memory from an external server device or the like via the network, or may be distributed in a state stored on a recording medium such as a CD-ROM (Compact Disc Read Only Memory), a DVD-ROM (Digital Versatile Disc Read Only Memory), or a semiconductor memory, and then installed into the memory from the recording medium.

[0194] The above description includes the following additional features: [Supplementary Note 1] A relay method in an in-vehicle communication system including a plurality of in-vehicle devices and a relay device that relays frames transmitted and received between the in-vehicle devices, the relay method including: a step in which a first in-vehicle device transmits a frame to be transmitted to a second in-vehicle device, the frame including first identification information capable of identifying a first communication line to which the second in-vehicle device is connected, to the relay device; and a step in which the relay device uses the first identification information included in the frame received from the first in-vehicle device to identify the first communication line to which the frame is to be transmitted.

[0195] [Supplementary Note 2] A frame transmission method in an on-board device that is mounted on a vehicle and transmits and receives frames to and from other on-board devices in the vehicle via a relay device, the frame transmission method comprising: a step of creating the frame including identification information that can identify a communication line to which the other on-board device is connected; and a step of transmitting the created frame to the relay device.

[0196] [Supplementary Note 3] A frame transmission program used in an on-board device that is mounted on a vehicle and transmits and receives frames to and from other on-board devices in the vehicle via a relay device, the frame transmission program causing a computer to function as: a creation unit that creates the frame including identification information that can identify a communication line to which the other on-board device is connected; and a transmission unit that transmits the frame created by the creation unit to the relay device.

[0197] [Supplementary Note 4] An in-vehicle device that is mounted on a vehicle and transmits and receives frames to and from other in-vehicle devices in the vehicle via a relay device, the in-vehicle device comprising a processing circuit, the processing circuit creating the frame including identification information that can identify a communication line to which the other in-vehicle device is connected, and transmitting the created frame to the relay device.

[0198] [Supplementary Note 5] A relay method in a relay device that relays frames transmitted and received between on-board devices, the relay device comprising: a step of receiving, from the on-board device that is the source of the frame, the frame including identification information that can identify a communication line to which the on-board device that is the destination of the frame is connected; and a step of specifying the communication line to which the frame is to be sent using the identification information included in the received frame.

[0199] [Supplementary Note 6] A relay program used in a relay device that relays frames transmitted and received between in-vehicle devices, causing a computer to function as: a relay unit that receives a frame from the in-vehicle device that is the source of the frame, the frame including identification information that can identify a communication line to which the in-vehicle device that is the destination of the frame is connected; and a processing unit that specifies the communication line to which the frame is to be sent, using the identification information included in the frame received by the relay unit.

[0200] [Supplementary Note 7] A relay device that relays frames transmitted and received between on-board devices, comprising a processing circuit, wherein the processing circuit receives the frame from the on-board device that is the source of the frame, the frame including identification information that can identify a communication line to which the on-board device that is the destination of the frame is connected, and specifies the communication line to which the frame is to be sent using the identification information included in the received frame.

[0201] REFERENCE SIGNS LIST 1 Vehicle 11 Communication unit 12, 23 Processing unit 13, 24 Storage unit 21, 21A, 21B, 21C Communication port 22 Relay unit 51, 51A, 51B, 52, 52A, 52B Communication bus 101, 101A, 101B Relay device 202 In-vehicle ECU (in-vehicle device) 301, 302 In-vehicle communication system 401 In-vehicle network Tb10, Tb20, Tb21 Flag table

Claims

1. An in-vehicle communication system comprising: a plurality of in-vehicle devices; and a relay device that relays frames transmitted and received between the in-vehicle devices; wherein a first in-vehicle device transmits a frame to be sent to a second in-vehicle device, another in-vehicle device, to the relay device, including first identification information that can identify a first communication line to which the second in-vehicle device is connected; and wherein the relay device uses the first identification information included in the frame received from the first in-vehicle device to identify the first communication line to which the frame is to be sent.

2. The in-vehicle communication system described in claim 1, wherein the in-vehicle device communicates with a plurality of the second in-vehicle devices, the plurality of second in-vehicle devices are each connected to a plurality of the first communication lines, each of the first communication lines is assigned a priority, and the frame further includes priority information indicating the priority of the first communication line corresponding to the first identification information included in the frame.

3. The in-vehicle communication system according to claim 2, wherein the frame includes the first identification information, the storage location in the frame or the value of which is set according to the priority.

4. An in-vehicle communication system as described in any one of claims 1 to 3, wherein the in-vehicle device communicates with a plurality of the second in-vehicle devices, the plurality of second in-vehicle devices are each connected to a plurality of the first communication lines, the relay device includes a plurality of communication ports to which the plurality of first communication lines are respectively connected, the relay device acquires correspondence information indicating the correspondence between the communication ports and the first identification information, and identifies the first communication line to which the frame is to be sent using the first identification information included in the frame received from the first in-vehicle device and the acquired correspondence information.

5. The in-vehicle communication system according to claim 4, wherein the in-vehicle communication system comprises a plurality of relay devices, at least one of the plurality of relay devices is connected to another relay device, the second in-vehicle device is connected to the other relay device via a second communication line, and the correspondence information indicates the correspondence between the communication port, the first identification information, and second identification information capable of identifying the second communication line.

6. An in-vehicle communication system as described in any one of claims 1 to 5, wherein the frame further includes third identification information capable of identifying a third communication line connecting the first in-vehicle device and the relay device, and when the relay device receives the frame from the in-vehicle device, it outputs a response frame to the third communication line corresponding to the third identification information included in the frame.

7. An on-board device that is mounted on a vehicle and transmits and receives frames to and from other on-board devices in the vehicle via a relay device, the on-board device comprising: a creation unit that creates the frame including identification information that can identify the communication line to which the other on-board device is connected; and a transmission unit that transmits the frame created by the creation unit to the relay device.

8. A relay device that relays frames transmitted and received between on-board devices, comprising: a relay unit that receives a frame from the on-board device that is the source of the frame, the frame including identification information that can identify a communication line to which the on-board device that is the destination of the frame is connected; and a processing unit that uses the identification information included in the frame received by the relay unit to specify the communication line to which the frame is to be sent.

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