JP6339258B2 - In-car communication system - Google Patents

Description

  The present invention relates to an in-vehicle communication system that divides information collected by one in-vehicle unit into frames and transmits the frames to other in-vehicle units.

  Conventionally, as shown in Patent Document 1 and Patent Document 2, diagnostic information collected by an ECU (electronic control unit) or the like and recorded in the ECU or the like is communicated wirelessly from the ECU or the like through an in-vehicle communication unit. Thus, a vehicle diagnosis system has been proposed that transmits the information to an information center outside the vehicle so that the information center can perform remote diagnosis of the vehicle.

  Moreover, although it is not a vehicle diagnostic system, as shown in patent document 3, it waits for the confirmation signal with respect to each request signal to return between each other in communication between ECUs in a vehicle, and next request signal An in-vehicle network device that employs a data transmission method for transmitting a so-called handshake method has been proposed.

JP 10-194095 A ([Summary]) JP 2006-25048 A ([Summary]) JP 2011-114371 A ([0012])

  In general, in-vehicle communication, information is divided into frames (data frames) with a fixed period in response to a request for multiplex communication, and the divided frames are transmitted from the transmission side to the reception side via a communication line (bus line). It is configured.

  Therefore, on the information receiving side, it is necessary to receive all of the divided frames in order to accurately reproduce the information.

  Here, in order to reliably determine whether or not all the divided frames have been received, a handshake method as described in Patent Document 3 may be employed.

  By the way, in order to analyze troubles occurring in the vehicle, an ECU (electronic control unit) for vehicle control continuously collects (logs) travel information when it is in an energized state (starting state). When an occurrence of a malfunction is detected, the occurrence of the malfunction is used as a trigger, and travel record information within a predetermined time immediately before the occurrence of the trigger is used as diagnostic information to an external information center through a communication relay unit connected to the in-vehicle network. Configured to send.

  In this case, from the viewpoint of ensuring the reliability of the in-vehicle network configured by the vehicle control ECU and the high bus load of the in-vehicle network, the communication relay is performed with respect to the vehicle control ECU of the in-vehicle network. Since the transmission of information from the unit side is prohibited, the handshake method cannot be adopted.

  When transmitting information from the in-vehicle ECU to the communication relay unit, the in-vehicle ECU that is the information transmission side and the frame-divided information from the in-vehicle ECU and the information center that transmits the information to the information center The communication relay unit needs to be in an energized state.

  However, during transmission of information from the ECU to the communication relay unit in the vehicle using a divided frame, the communication relay unit changes from the energized state to the non-energized state (shut off state) due to a change in the key position of the key switch in the vehicle. In the case of transition, a situation in which communication from the ECU to the communication relay unit is interrupted due to a change in the key position, that is, a situation in which communication is interrupted in the middle of communication of a frame obtained by dividing information occurs.

  In this case, the ECU in the energized state continues to send the remaining divided frames of information to the communication relay unit, but the communication relay unit in the non-energized state (blocked state) Since the frame cannot be received, as a result, there is a problem that the communication relay unit cannot receive all the information such as the diagnostic information.

  That is, conventionally, when transmitting information such as diagnostic information to the outside via in-vehicle communication from the ECU to the communication relay unit, all of the divided frames constituting the information are transferred from the ECU to the communication relay. There is an inconvenience that information cannot be completely prevented from being lost due to a change in the key position because a method for reliably delivering the information to the unit by in-vehicle communication has not been established.

  The present invention has been made in consideration of such a problem, and even if a key position change occurs during transmission of information in in-vehicle communication, a frame is transmitted from the information transmission side to the information reception side. It is an object of the present invention to provide an in-vehicle communication system that can reliably transmit all of the divided information.

Vehicle communication system according to the present invention comprises a key switch for changing the key position of the vehicle, the first vehicle unit, to divide the information into the frame, the first vehicle divided frame while counting the divided transmission frame number A second in-vehicle unit that transmits to the unit, and when the second in-vehicle unit detects a change in the key position during transmission, the second in-vehicle unit retransmits the divided frames by returning a predetermined number of transmission frame numbers. It is characterized by that.

  According to this invention, information is divided into frames and transmitted from the second in-vehicle unit to the first in-vehicle unit, and when a change in key position is detected during transmission of the divided frames, the transmission frame number is returned by a predetermined number. Since the divided frames are retransmitted, even if the key position changes during the transmission of the information in the in-vehicle communication, the first in-vehicle unit on the information reception side from the second in-vehicle unit on the information transmission side. All of the information divided into frames can be reliably transmitted to the unit.

  In this case, the first vehicle-mounted unit is activated when the key position is the accessory position and the on-position, the second vehicle-mounted unit is activated when the key position is the on-position and the starting position, and the second vehicle-mounted unit is When the key position is changed from the accessory position to the ON position, and when the key position is changed from the starting position to the ON position, the transmission frame number is returned by a predetermined number to retransmit the divided frames. You can do it.

  The second in-vehicle unit is configured to interrupt the transmission of the divided frames when the key position is the starting position, in other words, when the first in-vehicle unit is not activated. In this case, the frame is not transmitted wastefully.

  In this case, the information may be failure diagnosis information that is large-capacity data.

  Further, the first in-vehicle unit may not be provided with a function for transmitting information to the second in-vehicle unit.

  According to the present invention, when the second in-vehicle unit divides information into frames from the second in-vehicle unit to the first in-vehicle unit and detects a change in key position during transmission, the transmission frame number is returned by a predetermined number. Therefore, even if a key position change occurs during the transmission of information in in-vehicle communication, all of the information divided into frames is transferred from the information transmission side to the information reception side. The effect that it can transmit reliably is achieved.

1 is a schematic system configuration diagram of a vehicle remote diagnosis system to which an in-vehicle communication system according to this embodiment is applied. It is an interior schematic diagram showing an engine ECU provided in an engine room of a vehicle, an audio unit provided in a dashboard, a portable terminal placed on a dashboard tray, and the like. It is explanatory drawing of the electricity supply / interruption | blocking table which shows the response | compatibility of the energization state and interruption | blocking state of engine ECU and an audio unit with respect to the change position of a key position. It is a flowchart with which operation | movement description of an in-vehicle communication system is provided. It is a timing chart used for operation | movement description of a communication system in a vehicle.

  Hereinafter, preferred embodiments of an in-vehicle communication system according to the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a schematic system configuration diagram of a remote diagnosis system 12 for a vehicle 14 to which an in-vehicle communication system 10 according to this embodiment is applied.

  2 shows an engine ECU 16 (also referred to as FIECU) provided in the engine room of the vehicle 14, a display audio unit (hereinafter also referred to as DA unit or simply audio unit) 20 provided in the dashboard 18, a dash. It is an interior schematic diagram which shows portable terminals (portable communication terminal) 24, such as a smart phone, placed on the board tray.

  The engine ECU 16 and the audio unit 20 that also functions as a communication relay unit are connected to each other through a known wired communication line 30 (bus line) such as a CAN (Controller Area Network) that is an in-vehicle network.

  The audio unit 20 and the portable terminal 24 are connected by wire or wireless. In this embodiment, the wireless communication is performed by a short-range wireless communication method.

  The portable terminal 24 is connected to an information center 40 that is a collection / distribution center of information (diagnostic information in this embodiment) via a communication network 36 such as a mobile communication network outside the vehicle or a public communication network.

  Information collected in the information center 40 is appropriately processed in the information center 40 as necessary, and the processed information is sent to a quality control department 42 such as a factory and a service department 44 such as a dealer via the communication network 36. Supplied.

  In addition to an engine ECU 16 that controls engine ignition, throttle valve opening adjustment, cylinder deactivation, variable valve timing, and the like, an in-vehicle communication line 30 includes ABS (anti-lock braking, System) and the like, an electric power steering ECU that assists the steering force of the handle 46, and a body ECU that controls the locking and unlocking of the doors and the power source and the cranking by controlling the starter motor. Etc. are connected. A key switch 50 is connected to the body ECU.

  An ECU (Electronic Control Unit) is a computer including a microcomputer. In addition to a CPU (Central Processing Unit), a storage unit such as a ROM (including EEPROM) as a memory, and a RAM (random) as a memory. Access memory), input / output devices such as A / D converters and D / A converters, communication interfaces, timers, etc., and the CPU reads and executes the programs recorded in the ROM. It functions as various function realization units (function realization means) such as a control unit, a calculation unit, and a processing unit.

  When the key position of the key switch 50 is in the ON (on) position and the START (starting) position, these ECUs provide diagnostic information (running information) for diagnosing its own operating state, so-called on-board diagnostic information, In a storage unit (storage device) in the ECU, a so-called log is recorded (stored) sequentially for a predetermined time (a predetermined memory capacity) by a first-in first-out method.

  For example, when the key position of the key switch 50 is in the ON position and the START position, the engine ECU 16 continuously outputs diagnostic information (travel information) such as the water temperature and the engine speed, for a predetermined time before the current time. Until then, record it in its own storage device.

  When each ECU detects the occurrence of a failure in the diagnosis information (running information), the information (diagnosis information, failure diagnosis information, failure) logged in the predetermined time immediately before the occurrence of the failure is triggered by the occurrence of the failure. Diagnostic information) is divided into frames and transmitted to the audio unit 20 which is an information relay unit via the communication line 30.

  In this embodiment, as an example, diagnostic information (diagnostic information for a predetermined time immediately before the occurrence of the defect) is transmitted from the engine ECU 16 to the audio unit 20 via the communication line 30 and divided into frames to be transmitted as a group of diagnostics. It is memorized as information.

  The audio unit 20 transmits the stored diagnostic information to the information center 40 through the portable terminal 24 in a timely manner.

  The audio unit 20 outputs to the speaker 58 an audio signal for enjoying various musical sounds such as a tuner, a compact disc, etc., which are music sources. The audio unit 20 has a one-way communication function (one-way communication relay function) that only receives divided frames (only functions as a receiving side) from each ECU (including the engine ECU 16). The one-way communication function is limited from the viewpoint of ensuring the reliability of the in-vehicle network configured by the vehicle control ECU such as the engine ECU 16 and the high bus load on the communication line 30 of the in-vehicle network. This is because the audio unit 20 and other components that are not involved in vehicle control cannot be transmitted to the vehicle control engine ECU 16 of the in-vehicle network. The audio unit 20 can be replaced with a navigation device or the like having a communication function with the outside.

  Communication between the ECUs (not shown) in both directions is possible through the communication line 30 and multiplex communication in the vehicle is possible using the frames divided at a constant period.

  Next, a key switch 50 such as a push button switch is mounted on the dashboard 18 near the handle 46.

  As shown in the energization / shut-off (start / stop) table 56 of FIG. 3, the key switch 50 has an OFF (off) position, an ACC (accessory) position, an ON (on) position, and a START (starting) position. It is possible to change to one key position.

  In this case, the engine ECU 16 and the audio unit 20 are brought into an energized state (start-up state) or a cut-off state (stop state) depending on the key position.

  The energized state or the interrupted state means that the relays 52 and 54 (contact points) are opened and closed through the key switch 50, so that the power source Vcc (DC power source, DC constant voltage) in the vehicle is changed between the engine ECU 16 and the audio unit 20. This means that the power supply terminal is energized (relays 52 and 54 are closed) or disconnected (relays 52 and 54 are open).

  At the OFF position, the ACC position, the ON position, and the START position, the engine ECU 16 is cut off, cut off, energized, and energized, respectively, and the audio unit 20 is turned off, energized, energized, and cut off, respectively. The

  As the key position, the OFF position is a position where the supply of electricity to the electrical components in the vehicle (here, the engine ECU 16 and the audio unit 20) is cut off, and the ACC position is a partial electrical component such as audio (here, the audio unit 20). ) The accessory position for energizing electricity and the ON position are the positions for energizing all the electrical components including the air conditioner (here, the engine ECU 16, the audio unit 20, the fuel injection device, etc.) and the START position are, for example, This is a position where a power source (engine, fuel cell, etc.) is started such that electricity is supplied to the starting motor for cranking. In this embodiment, a push button switch is adopted as the key switch 50. However, the present invention is not limited to this, and the key switch 50 can also be applied to a conventional rotary switch.

  Next, the operation of the in-vehicle communication system 10 according to this embodiment basically configured and operated as described above will be described in detail based on the flowchart shown in FIG. 4 and the timing chart shown in FIG. It is the engine ECU 16 that executes the program according to the flowchart. However, since it is complicated to refer to it every time, the program is referred to as appropriate.

  The timing chart shown in FIG. 5 shows, for example, the above-described diagnostic information when the engine ECU 16 detects the occurrence of a malfunction at a time point t1 when the vehicle 14 is on the street (riding in the town). (Failure diagnosis information) is recorded and divided into frames 1 to 15 and transmission of the divided frames 1 to 15 to the audio unit 20 is started. At time t2 to t3, the key position of the key switch 50 is changed from the ON position. The vehicle 14 is parked at the destination by switching to the OFF position through the ACC position.

  Thereafter, at time t4, in order for the vehicle 14 to go from the destination to another destination, the key position of the key switch 50 is changed from the OFF position to the START position between times t4 and t7, and the engine is started. Thereafter, this corresponds to a situation where the vehicle is traveling to another destination at the ON position of the key position.

  Therefore, in FIG. 5, when the vehicle 14 is traveling (the relays 52 and 54 are closed and the power source Vcc is supplied to the engine ECU 16 and the audio unit 20 and both are energized), the engine ECU 16 When, for example, an increase in the engine temperature or the like exceeding a threshold temperature is detected, this is detected as the occurrence of a problem, and the occurrence of this problem is used as a trigger, and travel record information within a predetermined time immediately before the occurrence of the trigger is transmitted as diagnostic information. While preparing, the process by the flowchart shown in FIG. 4 is started.

  When starting the processing according to the flowchart, the engine ECU 16 clears its own ON history flag Fon and start history flag Fstart (Fon ← 0, Fstart ← 0) by the initialization process.

  After the initialization process, in step S1, the engine ECU 16 determines whether or not the key position is in the ON position. Since the key position is in the ON position (step S1: YES), the process proceeds to step S2.

  In step S2, the engine ECU 16 determines whether or not its own ON history flag Fon is set (Fon = 1).

  In this case, in the first determination, since the ON history flag Fon is cleared (Fon = 0) by the initialization process, it becomes negative (step S2: NO), and the ON history flag Fon is set in step S3. Set (Fon ← 1).

  Next, in step S4, the count value CTR of the transmission counter is subtracted by a predetermined value, in this embodiment, the value “2” (referred to as the return number of the transmission frame number or the retroactive number of the transmission frame number). The return number of the transmission frame number is determined in advance for each vehicle type by simulation or the like.

  In this embodiment, the storage device of the engine ECU 16 is described as storing the data for 15 frames as the diagnostic information for the sake of simplicity. However, the diagnostic information is actually For example, the data may be several thousand frames.

  Since the frame has not yet been transmitted at the processing time t1 of the first step S4, the count value CTR of the transmission counter of itself (engine ECU 16) is CTR = 0, and the count value CTR is 0 or less. Therefore, in the first subtraction process of step S4, the count value CTR remains unchanged at CTR = 0.

  Subsequently, in step S5, the engine ECU 16 divides the diagnostic information (on-board diagnostic information) into 15 frames from the transmission frame numbers 1 to 15 to the first frame 1 (in FIG. 5, The number “1” is enclosed in a square.) Is transmitted to the audio unit 20 via the communication line 30, and when the transmission is completed, the count value CTR of the transmission counter is incremented (increased) to CTR = 1. The audio unit 20 stores the received frame 1 in its own storage device.

  Next, after step S1: YES (continuation of the key position ON position) and step S2: YES (Fon = 1), it is determined in step S6 whether or not the key position is the START position, and is not the START position. Since (S6: NO), it progresses to step S7. In step S7, it is determined whether or not the start history flag Fstart is set (Fstart = 1). At first, since it is not set (step S7: NO), frame 2 is transmitted in step S5. When the transmission is completed, the count value CTR of the transmission counter is incremented to CTR = 2.

  Further, the process of step S1: YES → step S2: YES → step S6: NO → step S7: NO → step S5 is repeated to transmit frame 3, and the count value CTR of the transmission counter is incremented to CTR = 3.

  As shown in FIG. 5, when the key switch 50 is operated by the user at the time t2 during transmission of the next frame 4 and the key position is changed from the ON position to the ACC position, the relay 52 is opened. The ECU 16 transitions from the energized state to the cut-off state, and execution of the program according to the flowchart of FIG. 4 is interrupted in the process of step S5.

  Accordingly, since the frame 4 indicated by hatching cannot be transmitted, the count value CTR of the transmission counter remains held at CTR = 3.

  When the key position of the key switch 50 is changed from the ACC position to the OFF position at time t3, the relay 54 is opened based on the energization / cutoff table 56, and the audio unit 20 is also in an operation stop state.

  At time t4, when the key position of the key switch 50 is changed from the OFF position to the ACC position again, the relay 54 is closed and the audio unit 20 becomes operable.

  Next, when the key position changes from the ACC position to the ON position at time t5 in FIG. 5, the relay 52 is also closed, and the engine ECU 16 changes from the shut-off state to the energized state (start-up state). At this time, the engine ECU 16 returns from the interruption, and after the initialization process (Fon ← 0, Fstart ← 0), the key position is changed to the ON position again in step S1 of the flowchart (step S1: YES). And the process proceeds to step S2.

  In step S2, the engine ECU 16 determines whether or not its own ON history flag Fon is set (Fon = 1).

  Since the ON history flag Fon is cleared (Fon = 0) in the initialization process, the result is negative (step S2: NO), and the ON history flag Fon is set (Fon ← 1) in step S3. .

  Next, in step S4, the count value CTR of the transmission counter is decremented by a predetermined value, the value “2”, and the count value CTR is returned from the held count value CTR = 3 to the count value CTR = 1 (rewinding). ).

  Next, in step S5, the engine ECU 16 refers to the count value CTR = 1, and transmits the frame 2 of the transmission frame number 2 to be transmitted next to the audio unit 20. The audio unit 20 stores the received frame 2 in its own storage device.

  Next, after step S1: YES (key position ON position) and step S2: YES (Fon = 1), it is determined in step S6 whether or not the key position is the START position, and not the START position (S6). : NO), the process proceeds to step S7. In step S7, it is determined whether or not the start history flag Fstart is set (Fstart = 1). If not (step S7: NO), the next frame 3 is transmitted in step S5. The count value CTR of the transmission counter is incremented to CTR = 3.

  Further, Steps S1: YES → Step S2: YES → Step S6: NO → Step S7: NO → Step S5 is repeated twice to transmit frames 4 and 5.

  As shown in FIG. 5, when the key switch 50 is operated by the user at time t6 during transmission of the frame 6 and the key position changes from the ON position to the START position, the starter motor is driven by a body ECU (not shown). In addition, the determination of step S1 becomes negative (S1: NO), and the relay 54 is opened based on the energization / interruption table 56, so that the audio unit 20 transitions from the energized state to the interrupted state. .

  At the same time that the determination in step S1 is negative (step S1: NO), the transmission process is disabled (non-permitted state), and the engine ECU 16 interrupts the transmission process after transmitting the frame 6 currently being transmitted. At this time, the count value CTR of the transmission counter is held at CTR = 6. Note that in this case, the audio unit 20 is in a blocked state and cannot receive the frame 6.

  Next, in step S8, it is determined whether or not the key position is in the START position. Since the key position is in the START position, the determination becomes affirmative (step S8: YES), and in step S9, the own START history flag Fstart is determined. Is set (Fstart ← 1), and the ON history flag Fon is cleared (Fon ← 0) in step S10.

  Next, the transmission process is not performed while the process of step S1: NO → step S8: YES → step S9 → step S10 is repeated.

  Next, when the key position changes from the START position to the ON position at time t7 after the engine is detonated for the first time, the determination in step S1 becomes affirmative (step S1: YES), and the audio unit 20 is energized from the shut-off state. Transition to the state (see the energization / shut-off table 56 in FIG. 3).

  Next, since the determination in step S2 is negative (Fon = 0), the ON history flag Fon is set (Fon → 1) in step S3.

  Next, in step S4, the count value CTR of the transmission counter is subtracted by a predetermined value, the value “2”, and the count value CTR is returned (rewinded) from CTR = 6 to CTR = 4.

  Next, in step S5, the engine ECU 16 refers to the count value CTR = 4 and transmits the frame 5 of the transmission frame number 5 to be transmitted next to the audio unit 20. The audio unit 20 stores the received frame 5 in its own storage device.

  Next, after step S1: YES (key position ON position) and step S2: YES (Fon = 1), it is determined in step S6 whether or not the key position is the START position, and not the START position (S6). : NO), the process proceeds to step S7. In step S7, it is determined whether or not the start history flag Fstart is set (Fstart = 1). Since it is set (step S7: YES), the start history flag Fstart is cleared (Fstart) in step S11. ← 0).

  In step S5, transmission processing for the next frame 6 is performed, and the count value CTR of the transmission counter is incremented to CTR = 6. Further, step S1: YES → step S2: YES → step S6: NO → step S7: NO → step S5 is repeated to transmit frame 7, frame 8,... The transmission of the diagnostic information up to the audio unit 20 is terminated.

  In this case, in the audio unit 20, as diagnostic information, the frame 1 is once, the frame 2 is twice, the frame 3 is twice, the frame 4 is twice, the frame 5 is twice, and the frame 6 is once (time t6). Note that frame 6 in the frame is in a blocked state and cannot be received.), Frames 7 to 15 are received once each, but frames 1 to 15 are received at least once. Therefore, the information transmitted from the engine ECU 16 can be reliably (completely) captured and reproduced (demodulated) without missing information.

  Thereafter, when the audio unit 20 is connected to the portable terminal 24, the audio unit 20 transmits the diagnostic information to the information center 40 via the portable terminal 24 and the communication network 36 when it is not connected. Send.

  Information received and collected by the information center 40 is appropriately processed by the information center 40, and the processed information is supplied to a quality control department 42 such as a factory and a service department 44 such as a dealer via the communication network 36. The

  In this case, the service department 44 can contact the user of the vehicle 14 in order to apply the process according to the diagnostic information to the vehicle 14.

  When the engine ECU 16 has a so-called off-delay function, the frame 4 can be transmitted and the audio unit 20 can receive the frame 4, but the audio unit 20 is cut off. The frame 6 cannot be received by the audio unit 20.

  In the communication processing according to the prior art (prior art), as shown at the bottom of FIG. Therefore, reliable reproduction (demodulation) of information cannot be performed.

[Summary of embodiment]
As described above, vehicle communication system 10 according to this embodiment includes a key switch 50 for changing the key position of the vehicle 14, the audio unit 20 as a first vehicle unit, information such as diagnostic information to the frame An engine ECU 16 serving as a second vehicle-mounted unit that divides and transmits the divided frames to the audio unit 20 while counting (counting) the divided transmission frame numbers.

  In this case, when the engine ECU 16 divides the previously logged (collected) information into frames 1 to 15 and transmits them sequentially to the audio unit 20, for example, the key position during the transmission of the frame 6 is used. Is detected (for example, ON position → START position → ON position, etc.), the transmission frame number (transmission counter count value CTR = 6) is returned by a predetermined number “2” (sequentially transmitted by a predetermined number “2”). Since the count value CTR of the counter is set to CTR = 4), and retransmission is performed from the frame 5 of the transmission frame number 5 to be transmitted next, the key position changes during the transmission of the information in the in-vehicle communication. Even if it occurs, it is possible to reliably transmit all of the information divided into frames from the information transmitting side to the information receiving side.

  More specifically, the audio unit 20 is activated when the key position is the ACC position and the ON position, and the engine ECU 16 is activated when the key position is the ON position and the START position. When the position is changed to the ON position (time point t5) and when the position is changed from the START position to the ON position (time point t7), a predetermined number of transmission frame numbers (transmission counter count value CTR) are set. The frame is retransmitted by returning “2”.

  When the key position is the START position, in other words, when the audio unit 20 is not activated (time t6 to t7), the engine ECU 16 interrupts transmission of the divided frames. There is no wasteful transmission of frames.

  Even if the information is large-capacity data such as failure diagnosis information (log information when trouble occurs), all frames can be reliably transmitted from the engine ECU 16 to the audio unit 20 with a simple configuration without handshaking. As a result, all frames of the failure diagnosis information can be transmitted from the audio unit 20 to the information center 40 via the portable terminal 24 (via).

  That is, the audio unit 20 may not be provided with a function for transmitting information to the engine ECU 16.

  Note that the present invention is not limited to the above-described embodiment, and it is needless to say that various configurations can be adopted based on the contents described in this specification.

DESCRIPTION OF SYMBOLS 10 ... In-vehicle communication system 12 ... Remote diagnostic system 14 ... Vehicle 16 ... Engine ECU
20 ... Audio unit 24 ... Mobile terminal 40 ... Information center 50 ... Key switch

Claims (3)

A key switch that changes the key position of the vehicle,
A first in-vehicle unit;
Dividing the information into the frame, the division frame while counting the divided transmission frame number and a second vehicle-mounted unit to be transmitted to the first vehicle unit,
The first in-vehicle unit is activated when the key position is an accessory position and an on position;
The second vehicle unit, wherein the key position is activated in the on position and the starting position,
The second in-vehicle unit is
When the key position detects a change from the on position to the accessory position or the starting position during transmission of the divided frame, the transmission is interrupted,
If the key position the accessory position 置又is that changes to the ON position from the previous SL starting position, characterized in that the retransmission of the divided frame a transmission frame number returns a predetermined number from the time of interruption of the transmission In-vehicle communication system. The in-vehicle communication system according to claim 1 ,
The in-vehicle communication system, wherein the information is failure diagnosis information. The in-vehicle communication system according to claim 1 or 2 ,
The in-vehicle communication system, wherein the first in-vehicle unit is not provided with a function of transmitting information to the second in-vehicle unit.

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