Electronic control device and communication diagnostic method

Abstract

To provide an electronic control device and a communication diagnosis method capable of inhibiting determination of a communication abnormality by mistake accompanying program rewriting in the electronic control device.SOLUTION: An electronic control device and a communication diagnosis method determine normality or abnormality of data reception from other electronic control devices connected to an on-vehicle network, determine normality or abnormality of data transmission to a communication line of the on-vehicle network when abnormality of the data reception is determined, determine that the other electronic control devices are rewriting a program when normality of the data transmission is determined, and invalidate a determination result of the abnormality of the data reception.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to an electronic control unit and a communication diagnosis method, and to a technique for diagnosing an abnormality in communication in an in-vehicle network. [Background technology]

[0002] The in-vehicle control system disclosed in Patent Document 1 utilizes a network communication path such as a CAN implemented in an electronic control unit (ATCU) of a vehicle's automatic transmission to allow another electronic control unit to function as a monitoring device for the ATCU, with the other monitoring electronic control unit controlling the power relay of the ATCU. Here, the other monitoring electronic control device shuts off the ATCU's shutoff circuit for a certain period of time and detects a breakdown in communication from the ATCU, thereby diagnosing a functional malfunction of the ATCU's power relay. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6364486 Summary of the Invention [Problem to be solved by the invention]

[0004] However, when a program is being rewritten in an electronic control device connected to an in-vehicle network, other electronic control devices may mistakenly determine that a communication abnormality has occurred because they have stopped receiving data from the electronic control device being rewritten, and may implement fail-safe measures or save a diagnostic history of the communication abnormality.

[0005] The present invention has been made in consideration of the current situation, and its purpose is to provide an electronic control device and a communication diagnosis method that can prevent erroneous determination of communication abnormalities due to program rewriting in the electronic control device. [Means for solving the problem]

[0006] Therefore, as one aspect thereof, the electronic control device of the present invention is an electronic control device connected to an in-vehicle network, and includes a reception diagnosis unit that judges whether data reception from other electronic control devices connected to the in-vehicle network is normal or abnormal, a transmission diagnosis unit that judges whether data transmission to a communication line of the in-vehicle network is normal or abnormal, and a judgment unit that finally judges whether communication is normal or abnormal based on the judgment results of the reception diagnosis unit and the judgment results of the transmission diagnosis unit. Here, when the reception diagnostic unit determines that there is an abnormality in data reception and the transmission diagnostic unit determines that the data transmission is normal, the determination unit invalidates the determination result of the reception diagnostic unit that there is an abnormality in data reception. In another aspect, the judgment unit makes a final judgment as to whether the communication is normal or abnormal depending on the result of judging whether the other electronic control device is in the process of rewriting a program based on the judgment result of the reception diagnosis unit and the judgment result of the transmission diagnosis unit.

[0007] In addition, as one aspect, the communication diagnostic method of the present invention is a communication diagnostic method in which an electronic control device connected to an in-vehicle network determines whether communication is normal or abnormal, and includes the steps of: determining whether data reception from other electronic control devices connected to the in-vehicle network is normal or abnormal; determining whether data transmission to a communication line of the in-vehicle network is normal or abnormal when it is determined that the data reception is abnormal; and determining that the other electronic control device is in the process of rewriting a program when it is determined that the data transmission is normal, and invalidating the determination result of the abnormality in data reception. Effect of the Invention

[0008] According to the above invention, it is possible to prevent a communication abnormality from being erroneously diagnosed due to program rewriting in the electronic control device. [Brief description of the drawings]

[0009] [Figure 1] 1 is a system diagram of an engine for a vehicle. [Diagram 2] FIG. 2 is a block diagram of a VTC control module and an engine control module (ECM). [Diagram 3] FIG. 1 is a block diagram of an in-vehicle network. [Figure 4] 4 is a flowchart showing each step of communication diagnosis by the VTC control module. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] An embodiment of the present invention will be described below. FIG. 1 shows an embodiment of an engine (internal combustion engine) mounted on a vehicle. The engine 100 includes an intake duct 102 , and further includes an intake air flow rate sensor 104 in the intake duct 102 for detecting an intake air flow rate QA of the engine 100 .

[0011] The intake valve 106 opens and closes the intake port 102a. The fuel injector 110 is disposed in the intake port 102a upstream of the intake valve 106, and injects fuel into the intake port 102a.

[0012] The fuel injected by the fuel injector 110 is drawn into the combustion chamber 108 together with air via the intake valve 106, and is ignited and burned by spark ignition from the spark plug 112. The pressure generated by the combustion pushes the piston 114 down towards the crankshaft 116, thereby driving the crankshaft 116 to rotate.

[0013] In addition, the exhaust valve 118 opens and closes the exhaust port 120a. When the exhaust valve 118 opens, the combustion gases in the combustion chamber 108 are exhausted to an exhaust pipe 120 .

[0014] A catalytic converter 122 incorporating a three-way catalyst is installed in the exhaust pipe 120 and purifies the exhaust gas flowing through the exhaust pipe 120 . An intake camshaft 124 rotatably driven by the crankshaft 116 controls the opening / closing timing and lift of the intake valve 106 , and an exhaust camshaft 126 rotatably driven by the crankshaft 116 controls the opening / closing timing and lift of the exhaust valve 118 .

[0015] A valve timing control system (hereinafter referred to as VTC) 128 is a device that changes the phase of the valve operating angle of the intake valve 106 by changing the relative rotational phase angle of the intake camshaft 124 with respect to the crankshaft 116 using an electric motor 130 as an actuator. The ignition module 132 has an ignition coil and a power transistor that controls the current supply to the ignition coil, and supplies ignition energy to the spark plug 112.

[0016] A VTC control module 200 controls the VTC 128 (electric motor 130), and an engine control module (hereinafter referred to as ECM) 202 controls the fuel injector 110, the ignition module 132, and the like. Each of the VTC control module 200 and the ECM 202 is an electronic control device equipped with a microcomputer including a microprocessor unit (MPU), a read only memory (ROM), a random access memory (RAM), and the like.

[0017] The VTC control module 200 and the ECM 202 are connected to an in-vehicle network 204 such as a Controller Area Network (CAN), and transmit and receive data to and from each other via the in-vehicle network 204 . However, the in-vehicle network 204 is not limited to CAN, and may be an in-vehicle network based on LIN (Local Interconnect Network), FlexRay (registered trademark), MOST (Media Oriented System Transport) (registered trademark), or the like.

[0018] The engine 100 is equipped with various sensors that detect the operating state of the engine 100 . As such various sensors, the engine 100 is equipped with, in addition to the intake air flow rate sensor 104, a crank angle sensor 206, a cam angle sensor 208, a motor rotation angle sensor 210, an accelerator opening sensor 212, a water temperature sensor 214, an air-fuel ratio sensor 216, and the like.

[0019] The crank angle sensor 206 outputs a rotation angle signal POS of the crankshaft 116 . The cam angle sensor 208 outputs a rotation angle signal CAM of the intake camshaft 124 . The motor rotation angle sensor 210 outputs a rotation angle signal MAS of the electric motor 130 which is the actuator of the VTC 128 .

[0020] The accelerator opening sensor 212 detects the depression amount of an accelerator pedal 218, in other words, the accelerator opening ACC. The water temperature sensor 214 detects the temperature TW of the coolant for the engine 100 . The air-fuel ratio sensor 216 is disposed in the exhaust pipe 120 upstream of the catalytic converter 122, and detects the air-fuel ratio AF of the mixture in the engine 100 based on the oxygen concentration in the exhaust gas.

[0021] The VTC control module 200 and the ECM 202 perform various control processes based on detection signals from the various sensors described above, an on / off signal from an ignition switch (IGNSW) 220 which is the main switch for starting and stopping the engine 100, and the like. The IGNSW220 is a switch that is turned on and off by the driver of the vehicle, and can be interpreted as an engine switch or a start switch.

[0022] FIG. 2 is a block diagram showing one embodiment of the configuration of the VTC control module 200 and the ECM 202. The VTC control module 200 includes a microcomputer 200A including an EEPROM 200A1 which is a non-volatile memory, a CAN communication circuit 200B, an input circuit 200C, a power supply circuit 200D, a command signal output circuit 200E, a voltage conversion circuit 200F, and a motor drive circuit 200G.

[0023] The CAN communication circuit 200B is connected to a communication line 204A (CAN bus) of the in-vehicle network 204, and the VTC control module 200 communicates mainly with the ECM 202 via the CAN communication circuit 200B. The input circuit 200C is a circuit that processes detection signals from various sensors, specifically, the rotation angle signal POS, the rotation angle signal CAM, and the rotation angle signal MAS, and outputs the processed signals to the microcomputer 200A.

[0024] The power supply circuit 200D is constantly supplied with a power supply voltage VBATT (for example, 12 V) from an in-vehicle battery 224 via a first diode 222. Furthermore, when the IGNSW 220 is turned on, the power supply voltage VBATT is supplied from the in-vehicle battery 224 through the IGNSW 220 and the second diode 226 to the power supply circuit 200D.

[0025] The power supply circuit 200D converts the power supply voltage VBATT into a power supply voltage VCC (for example, 5 V) for the microcomputer 200A, and supplies the power supply voltage VCC to the microcomputer 200A. When the command signal output circuit 200E receives the power supply voltage VBATT via the IGNSW 220, in other words, when the IGNSW 220 switches from off to on, it instructs the power supply circuit 200D to start the process of converting the power supply voltage VBATT into the power supply voltage VCC, in other words, to start supplying the power supply voltage VCC to the microcomputer 200A.

[0026] In addition, when the command signal output circuit 200E inputs a self-shutoff instruction signal S-SHUT from the microcomputer 200A, it instructs the power supply circuit 200D to stop the process of converting the power supply voltage VBATT into the power supply voltage VCC, in other words, to stop supplying the power supply voltage VCC to the microcomputer 200A. The voltage conversion circuit 200F is a circuit that converts the power supply voltage VBATT supplied via the IGNSW 220 into a signal Vm of a predetermined voltage (for example, about 2 V) and outputs the signal Vm to the CPU 200A.

[0027] The microcomputer 200A detects the on / off state of the IGNSW 220 based on the output of the voltage conversion circuit 200F, and when the IGNSW 220 switches from off to on, starts controlling the electric motor 130 of the VTC 128, and when the IGNSW 220 switches from on to off, executes a predetermined process and then outputs a self shut-off instruction signal S-SHUT to the command signal output circuit 200E, thereby self-shutting off the power supply. The motor drive circuit 200G includes an inverter for driving the electric motor 130, and controls the supply of electricity to the electric motor 130 based on a PWM control signal output by the microcomputer 200A.

[0028] On the other hand, the ECM 202 includes a microcomputer 202A, a CAN communication circuit 202B, and the like. The CAN communication circuit 202B is connected to a communication line 204A (CAN bus) of the in-vehicle network 204, and the ECM 202 communicates with external devices (in other words, other nodes) including the VTC control module 200 connected to the in-vehicle network 204 via the CAN communication circuit 202B.

[0029] The ECM 202 is supplied with a power supply voltage VBATT from an in-vehicle battery 224 via a power supply relay 221 , and is also supplied with the power supply voltage VBATT from the in-vehicle battery 224 via an IGNSW 220 . The power relay 221 is switched on and off by a relay control signal outputted from the ECM 202 .

[0030] The ECM 202 is started when the IGNSW 220 is turned on and the power supply voltage VBATT is supplied from the vehicle battery 224 via the IGNSW 220 . The started ECM 202 outputs a relay control signal to turn on the power supply relay 221, thereby turning on the power supply relay 221, so that the power supply voltage VBATT is supplied via the power supply relay 221 even if the IGNSW 220 is turned off. After the IGNSW 220 is turned off, the ECM 202 outputs a relay control signal to turn off the power supply relay 221, and automatically shuts off the power supply via the power supply relay 221.

[0031] FIG. 3 is a diagram showing the overall configuration of the in-vehicle network 204. As shown in FIG. In addition to the ECM 202, other electronic control devices mounted on the vehicle, such as an AT controller 250 that controls the automatic transmission and a PS controller 260 that controls the electric power steering, are connected as nodes to the communication line 204A1 of the in-vehicle network 204.

[0032] In addition, the ECM 202 and the VTC control module 200 are connected to the communication line 204A2 of the in-vehicle network 204. The in-vehicle network 204 may be a system in which all nodes such as the ECM 202, the AT controller 250, the PS controller 260, and the VTC control module 200 are connected to a single communication line 204A1.

[0033] Furthermore, when a program stored in the non-volatile memory of the ECM 202 is to be rewritten at a vehicle maintenance workshop or the like, the worker detachably connects the program rewriting device 300 to the communication line 204A of the in-vehicle network 204. Then, the program rewriting device 300 sends the new program data to the ECM 202 via the communication line 204A, and causes the ECM 202 to rewrite the program (hereinafter referred to as a reprogramming process).

[0034] When the IGNSW 220 is turned on and the ECM 202 and the VTC control module 200 are activated, the ECM 202 and the VTC control module 200 constantly communicate with each other via the in-vehicle network 204 . For example, the ECM 202 periodically calculates a target phase of the valve operating angle of the intake valve 106 (in other words, a target valve timing), and transmits data of the calculated target phase and the like to the communication line 204A.

[0035] The VTC control module 200 receives data such as the target phase data transmitted by the ECM 202, and controls the energization of the electric motor 130 based on the target phase data. In addition, the VTC control module 200 transmits data indicating the results of a fault diagnosis performed on the VTC 128, data on the detection results of the valve operating angle of the intake valve 106, and the like to a communication line 204A, and the ECM 202 receives these data.

[0036] In addition, the VTC control module 200 performs a communication diagnosis (a reception diagnosis and a transmission diagnosis) to determine whether the communication function between the VTC control module 200 and the ECM 202 is normal. If the VTC control module 200 determines that there is an abnormality in the communication function in the above communication diagnosis, it implements measures to address the communication abnormality.

[0037] Measures to deal with communication abnormalities include, for example, transitioning to a fail-safe mode, such as controlling VTC128 to the default, and recording and saving in EEPROM200A1 the history of the determination of an abnormality in the communication function and information indicating the situation when the communication function became abnormal. However, when the ECM 202 is in the process of being reprogrammed, the ECM 202 ceases sending data to the VTC control module 200 .

[0038] For this reason, when a reprogramming process is performed in the ECM 202, the VTC control module 200 will mistakenly determine that there is an abnormality in the communication function because data reception from the ECM 202 is interrupted, even though communication (transmission and reception) via the in-vehicle network 204 can be performed normally, in other words, the communication function is normal, and will unnecessarily implement countermeasures such as fail-safe processing or saving of abnormality diagnosis history. Therefore, in order to prevent erroneous judgment of communication abnormalities accompanying the reprogramming process of ECM202, VTC control module 200 is provided with, as software, a reception diagnosis unit which judges whether data reception from ECM202 is normal or abnormal, a transmission diagnosis unit which judges whether data transmission to communication line 204A is normal or abnormal, and a judgment unit which finally judges whether the communication is normal or abnormal based on the judgment results of the reception diagnosis unit and the transmission diagnosis unit.

[0039] In other words, the VTC control module 200 determines whether there is an abnormality in receiving data from the ECM 202 as the ECM 202 is reprogrammed, but if the communication line 204A etc. are in a normal state, data transmission to the communication line 204A is performed normally. Therefore, if data reception from ECM202 is abnormal but data transmission is normal, the VTC control module 200 determines that the abnormality in data reception is due to ECM202 interrupting data transmission due to the reprogramming process of ECM202, and invalidates the determination result of the abnormality in data reception.

[0040] The result of the abnormality determination can be invalidated, for example, by canceling the abnormality determination or canceling measures taken based on the abnormality determination. This prevents unnecessary implementation of countermeasures against communication abnormalities, such as fail-safe processing or saving of abnormality diagnosis history, even if a communication abnormality (data reception abnormality) is erroneously determined during the reprogramming process of ECM202.

[0041] FIG. 4 is a flowchart showing the steps of the communication diagnostic process performed by the VTC control module 200. In step S501, the VTC control module 200 determines whether the IGNSW 220 is on or off.

[0042] If the IGNSW 220 is in the ON state, the VTC control module 200 proceeds to step S502 and subsequent steps to perform a communication diagnosis, and if the IGNSW 220 is in the OFF state, the VTC control module 200 ends this routine as is and cancels the communication diagnosis. The on state of the IGNSW 220 is a state in which communication between the ECM 202 and the VTC control module 200 is always performed, and conversely, the off state of the IGNSW 220 is a state in which communication between the ECM 202 and the VTC control module 200 is cut off.

[0043] The VTC control module 200 determines whether data reception from the ECM 202 is normal or abnormal in step S502 (reception diagnosis section). The VTC control module 200 determines that an abnormality in data reception has occurred when the state in which data reception from the ECM 202 has been interrupted exceeds a set time.

[0044] The set time in the reception diagnosis in step S502 is adapted to a time that will not be reached during the interval between data receptions from the ECM 202 when the VTC control module 200 is communicating normally with the ECM 202. On the other hand, if the VTC control module 200 receives data from the ECM 202 periodically within the normal interval time and the interval time for receiving data from the ECM 202 has not reached the set time, it determines that the data reception is normal, that is, the data transmitted by the ECM 202 is being received normally.

[0045] If the VTC control module 200 determines in step S502 that an abnormality has occurred in the data reception from the ECM 202, the process proceeds to step S503. In step S503 (transmission diagnosis section), VTC control module 200 determines whether data transmission by itself to communication line 204A is normal or abnormal.

[0046] Then, when the transmission is normal, that is, data can be normally transmitted to communication line 204A, VTC control module 200 proceeds to steps S504 to S507 (determination section) and makes a final determination as to whether the communication is normal or abnormal. In step S504, the VTC control module 200 determines whether the engine 100 is stopped (stalling) or in operation.

[0047] The VTC control module 200 obtains the rotation angle signal POS of the crankshaft 116 and the rotation angle signal CAM of the intake camshaft 124 from the respective sensors as engine information relating to whether the engine 100 is operating or stopped. Therefore, in step S504, the VTC control module 200 determines whether the engine 100 is stopped or running based on the rotation angle signal POS and / or the rotation angle signal CAM.

[0048] In other words, if the rotation angle signal POS or the rotation angle signal CAM is vibrating, the VTC control module 200 determines that the engine 100 is in an operating state, and if the vibration of the rotation angle signal POS or the rotation angle signal CAM has stopped, the VTC control module 200 determines that the engine 100 is in a stopped state. However, the engine information used to determine whether the engine 100 is stopped or running is not limited to rotation signals such as the rotation angle signal POS and the rotation angle signal CAM. For example, the VTC control module 200 can determine whether the engine 100 is stopped or running based on engine information such as the intake air flow rate, the intake pipe negative pressure, the air-fuel ratio, and engine vibration.

[0049] If the VTC control module 200 determines in step S504 that the engine 100 is stopped, the process proceeds to step S505. In step S505, the VTC control module 200 determines whether or not the state in which it has determined that there is an abnormality in data reception, that it has determined that data transmission is normal, and that the engine 100 is stopped has continued for a set time period.

[0050] The set time in step S505 is based on the average time required for the ECM 202 reprogramming process and is adapted to the time that will be exceeded when the ECM 202 reprogramming process is performed. If the VTC control module 200 determines in step S505 that the duration exceeds the set time, the VTC control module 200 proceeds to step S506 and determines that the ECM 202 is undergoing a reprogramming process.

[0051] When the ECM 202 reprogramming process is being performed, the ECM 202 stops transmitting data to the VTC control module 200 and the like, and the VTC control module 200 determines that there is an abnormality in the data reception when data reception from the ECM 202 is interrupted. However, since the abnormality in data reception is not due to a failure in the communication function, such as a break in communication line 204A, data transmission by VTC control module 200 to communication line 204A is performed normally.

[0052] Therefore, even if the VTC control module 200 determines that there is an abnormality in receiving data from the ECM 202, if it determines that data transmission to the communication line 204A is normal, it can be inferred that the VTC control module 200 has determined that there is an abnormality in receiving data from the ECM 202 because the reprogramming process of the ECM 202 is in progress. Furthermore, if the ECM 202 is undergoing reprogramming processing, control of the engine 100 by the ECM 202 (fuel injection control, ignition control, etc.) is stopped, and the engine 100 stops operating.

[0053] Therefore, the VTC control module 200 determines whether there is an abnormality in data reception, determines whether data transmission is normal, and further determines that the ECM 202 is undergoing reprogramming processing on the condition that it has determined that the engine 100 is in a stopped state, thereby improving the accuracy of determining whether the ECM 202 is undergoing reprogramming processing. Furthermore, the process of reprogramming the ECM 202 typically takes several minutes.

[0054] Therefore, if the VTC control module 200 determines that there is an abnormality in data reception, determines that data transmission is normal, and further determines that the engine 100 is in a stopped state, this situation will continue for the normal required time for the reprogramming process if the ECM 202 reprogramming process is actually being performed. Therefore, the VTC control module 200 determines that the ECM 202 is undergoing reprogramming processing only if the reprogramming processing continues for a period of time that corresponds to the time required for the reprogramming processing, thereby improving the accuracy of determining whether the ECM 202 is undergoing reprogramming processing.

[0055] When the VTC control module 200 proceeds to step S506 and determines that the ECM 202 is undergoing a reprogramming process, the VTC control module 200 invalidates the determination result of the abnormality in data reception from the ECM 202 because the abnormality is not due to a failure of the communication function, such as a break in the communication line 204A. Normally, when the VTC control module 200 determines that there is a communication abnormality in the in-vehicle network 204, such as an abnormality in data reception from the ECM 202, it takes measures to deal with the communication abnormality (abnormality in data reception), such as storing a history of the abnormality determination in the EEPROM 200A1 or performing a fail-safe procedure to switch the control mode of the VTC 128 to a fail-safe mode.

[0056] However, during the reprogramming process of ECM 202, even if the communication function of in-vehicle network 204 is normal, VTC control module 200 may determine that there is an abnormality in data reception from ECM 202, and the implementation of measures to address the abnormality in data reception may end up being unnecessary measures based on an erroneous diagnostic result. Therefore, when the VTC control module 200 determines that the ECM 202 is undergoing a reprogramming process, it invalidates the abnormality determination result of the data reception from the ECM 202, and does not store the abnormality determination history or transition to fail-safe mode.

[0057] Therefore, even if the VTC control module 200 determines that there is an abnormality in data reception as a result of the reprogramming process of the ECM 202, the VTC control module 200 is prevented from storing an erroneous diagnostic history or erroneously implementing a fail-safe procedure, thereby improving the reliability of the communication diagnostic process. The invalidation of the data reception abnormality determination result can be realized by canceling the abnormality determination or canceling measures such as saving the abnormality determination history. Furthermore, when the VTC control module 200 determines that the ECM 202 is undergoing a reprogramming process, it can record information on the history of the reprogramming process performed in the ECM 202 in the EEPROM 200A1.

[0058] On the other hand, if the VTC control module 200 determines in step S502 that data reception from the ECM 202 is normal, the process proceeds to step S507, where it determines that the ECM 202 is not performing a reprogramming process but is controlling the engine 100. In other words, if data reception from ECM 202 is normal, it is determined that ECM 202 is transmitting data normally to VTC control module 200 and that no breaks or the like have occurred in communication line 204A.

[0059] Furthermore, when VTC control module 200 determines in step S503 that there is an abnormality in data transmission, that is, when it determines that there is an abnormality in data reception from ECM 202 and that there is an abnormality in data transmission to communication line 204A, it proceeds to step S507. Again, the VTC control module 200 determines that the ECM 202 is not in the process of reprogramming and is instead in control of the engine 100.

[0060] In addition, the determination of the communication abnormality (abnormality in data reception and data transmission) at this time is not influenced by the reprogramming process of the ECM 202, but it is assumed that a fault such as a break in the communication line 204A has actually occurred in the in-vehicle network 204. Therefore, when the VTC control module 200 proceeds from step S503 to step S507, it ultimately determines that an abnormality has occurred in the communication function of the in-vehicle network 204 without invalidating the communication abnormality determination result, and implements measures to deal with the abnormality determination, such as saving the abnormality determination history and transitioning to fail-safe mode.

[0061] Also, if the VTC control module 200 determines in step S504 that the engine 100 is operating, the VTC control module 200 proceeds to step S507 and determines that the ECM 202 is not in the reprogramming process but is controlling the engine 100. When proceeding from step S504 to step S507, the abnormality in data reception is not due to the reprogramming process of ECM202, and data transmission is normal, so although there is no condition that would disable transmission or reception, such as a break in communication line 204A, there is a possibility that an abnormality has occurred in the data transmission function of ECM202.

[0062] Therefore, when the VTC control module 200 proceeds from step S504 to step S507, it performs a process of saving a history of the data reception abnormality determination in EEPROM 200A1 without invalidating the result of the data reception abnormality determination, and performs a fail-safe procedure of switching the control mode of VTC 128 to the fail-safe mode based on the result of the data reception abnormality determination. Furthermore, when the VTC control module 200 determines in step S505 that the duration does not exceed the set time, the VTC control module 200 proceeds to step S507, where it determines that the ECM 202 is not undergoing a reprogramming process but is in control of the engine 100, and only when the duration exceeds the set time does it determine that the ECM 202 is undergoing a reprogramming process.

[0063] The technical ideas described in the above embodiments can be used in any suitable combination as long as no contradiction occurs. Furthermore, although the contents of the present invention have been specifically described with reference to preferred embodiments, it is obvious that a person skilled in the art can adopt various modified embodiments based on the basic technical concept and teachings of the present invention.

[0064] In the above embodiment, communication between the VTC control module 200 and the ECM 202 is shown, but the combination of electronic control devices is not limited to the VTC control module 200 and the ECM 202, and a similar communication diagnosis method can be applied to various combinations of electronic control devices connected to the in-vehicle network 204. For example, in a combination of ECM202 and an electronic control device that controls a variable compression ratio mechanism that varies the mechanical compression ratio of the engine, the electronic control device that controls the variable compression ratio mechanism can perform communication diagnosis according to the steps shown in the flowchart of Figure 4.

[0065] Moreover, at least one of steps S504 and S505 shown in the flowchart of FIG. 4 can be omitted. Furthermore, the measures implemented based on the result of the communication abnormality determination are not limited to saving a diagnostic history or switching to a fail-safe mode, but may also be, for example, activation of a warning means such as controlling the illumination of a warning light.

[0066] In addition, when the VTC control module 200 (first electronic control unit) determines that the ECM 202 (second electronic control unit) is undergoing a reprogramming process, it can transmit data indicating that the ECM 202 is undergoing a reprogramming process to another electronic control unit (third electronic control unit) that constitutes the in-vehicle network. [Explanation of symbols]

[0067] 100... engine, 200... VTC control module (electronic control unit), 202... ECM (another electronic control unit), 204... in-vehicle network, 204A... communication line

Claims

1. An electronic control device connected to an in-vehicle network, a reception diagnostic unit for determining whether data reception from other electronic control units connected to the in-vehicle network is normal or abnormal; a transmission diagnostic unit for determining whether data transmission to a communication line of the in-vehicle network is normal or abnormal; a determination unit that determines whether communication is normal or abnormal based on a determination result of the reception diagnosis unit and a determination result of the transmission diagnosis unit; Equipped with The determination unit is when the reception diagnostic unit determines that the data reception is abnormal and the transmission diagnostic unit determines that the data transmission is normal, the result of the reception diagnostic unit's determination that the data reception is abnormal is invalidated. Electronic control unit.

2. An electronic control device connected to an in-vehicle network, a reception diagnostic unit for determining whether data reception from other electronic control units connected to the in-vehicle network is normal or abnormal; a transmission diagnostic unit for determining whether data transmission to a communication line of the in-vehicle network is normal or abnormal; a determination unit that determines whether communication is normal or abnormal based on a determination result of the reception diagnosis unit and a determination result of the transmission diagnosis unit; Equipped with The determination unit is a final determination as to whether communication is normal or abnormal depending on a result of determining whether the other electronic control device is in the process of rewriting a program based on a determination result of the reception diagnosis unit and a determination result of the transmission diagnosis unit; Electronic control unit.

3. An electronic control device as claimed in claim 2, The determination unit is When the reception diagnosis unit determines an abnormality in data reception and the transmission diagnosis unit determines that the data transmission is normal, the other electronic control unit determines that a program is being rewritten, and invalidates the determination result of the abnormality in data reception. Electronic control unit.

4. An electronic control device as claimed in claim 2, The other electronic control device is an engine control module that controls an engine mounted in a vehicle, The determination unit is obtaining engine information regarding whether the engine is running or stopped; determining that the engine is stopped based on the engine information, determining that the reception diagnosis unit determines an abnormality in data reception, and determining that the transmission diagnosis unit determines that data transmission is normal, determining that the engine control module is in the process of rewriting a program. Electronic control unit.

5. An electronic control device as claimed in claim 4, The determination unit is a determination unit that the engine is stopped based on the engine information, the reception diagnosis unit determines that there is an abnormality in data reception, and when the transmission diagnosis unit determines that data transmission is normal, the engine control module determines that a program is being rewritten when the state continues for a set time period. Electronic control unit.

6. A communication diagnostic method for determining whether communication is normal or abnormal in an electronic control device connected to an in-vehicle network, comprising: determining whether data reception from other electronic control units connected to the in-vehicle network is normal or abnormal; determining whether data transmission to a communication line of the in-vehicle network is normal or abnormal when the abnormality in the data reception is determined; a step of determining that the other electronic control unit is in the process of rewriting a program when it is determined that the data transmission is normal, and invalidating a result of the determination that the data reception is abnormal; A communication diagnostic method comprising:

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