In-vehicle control device and fault diagnosis method

Abstract

To provide an on-vehicle control device which can perform self-diagnosis of a fault of a semiconductor relay device.SOLUTION: An on-vehicle control device 1 comprises: a first on-vehicle control device 10 having a semiconductor relay device 20 and a first control unit 30; and at least one second on-vehicle control device 110 connected on a downstream side of the semiconductor relay device 20. The first control unit 30 performs self-diagnosis of a fault of the semiconductor relay device 20 on the basis of a comparison result obtained by comparing a first current value of current flowing in the first on-vehicle control device 10 with a second current value of current flowing in the second on-vehicle control device 110.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an in-vehicle control device and a fault diagnosis method.

Background Art

[0002] In recent years, automobiles have been subject to exhaust gas regulations, and there has been an increasing demand for further migration to electronic electrification and power saving. Conventionally, fuses and mechanical relays have been used to distribute, energize, and cut off the in-vehicle power supply to each control device. When energizing each control device, since the mechanical relay needs to close the contacts, it is necessary to energize the coil built in the mechanical relay. At this time, since a coil energization amount of several tens of mA to several hundreds of mA is required, it has been an obstacle to power saving.

[0003] Therefore, there has been a market demand to replace the power supply function conventionally configured using fuses and mechanical relays with a semiconductor relay device. When replacing a fuse with a semiconductor relay device, when over-power is generated by an in-vehicle control device or load on the downstream side of the semiconductor relay device, a device for surely turning off the semiconductor relay device like conventional fuse blowing is required. In case the semiconductor relay device fails, since it is necessary to detect this failure, a circuit for diagnosing the failure of the semiconductor relay device has been required.

[0004] Patent Document 1 describes that "the voltage application circuit applies a diagnostic potential to the common connection node of the first and second transistors in a state where both the first and second transistors are controlled to be off. The voltage determination circuit determines the presence or absence of a short circuit failure of the first and second transistors by detecting a change in the diagnostic potential applied to the common connection node."

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] By the way, in the technology disclosed in Patent Document 1, when the failure diagnosis function for the semiconductor relay device fails, the vehicle control device misjudges the semiconductor relay device as normal even though the semiconductor relay device is in a failure state. As a result, when over-power occurs downstream of the semiconductor relay device, it is considered that the semiconductor relay device cannot correctly perform the operation of cutting off the original current.

[0007] The present invention has been made in view of such a situation, and an object thereof is to correctly diagnose a failure of a semiconductor relay device.

Means for Solving the Problems

[0008] The in-vehicle control device according to the present invention includes a first in-vehicle control device having a semiconductor relay device and a first control unit, and at least one second in-vehicle control device connected to the downstream side of the semiconductor relay device. The first control unit A first current value acquisition unit that acquires a semiconductor relay from a semiconductor relay device, a first communication unit that receives a second current value from a second in-vehicle control device, a second current value acquisition unit that acquires the second current value from the first communication unit, a comparison unit that compares the first current value received from the first current value acquisition unit with the second current value received from the second current value acquisition unit and outputs a comparison result, and a diagnosis unit that self-diagnoses a failure of the semiconductor relay device based on the comparison result. the first current value of the current flowing through the device

Figure 1

Effects of the Invention

[0009] According to the present invention, it is possible to correctly diagnose a failure of a semiconductor relay device. Problems, configurations, and effects other than those described above will be clarified by the description of the following embodiments.

Brief Description of the Drawings

[0010]

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiments for Carrying Out the Invention

[0011] Hereinafter, embodiments for carrying out the present invention will be described with reference to the accompanying drawings. In this specification and the drawings, components having substantially the same function or configuration are denoted by the same reference numerals, and redundant descriptions are omitted.

[0012] [First Embodiment] FIG. 1 is a block diagram showing an example of the overall configuration of an in-vehicle control device 1 according to the first embodiment. The in-vehicle control device (in-vehicle control device 1) includes a first in-vehicle control device (first in-vehicle control device 10) having a semiconductor relay device (semiconductor relay device 20) and a first control unit (first control unit 30), and at least one second in-vehicle control device (second in-vehicle control device 110) connected to the downstream side of the semiconductor relay device (semiconductor relay device 20). Here, configuration examples of the upstream first in-vehicle control device 10 and the downstream second in-vehicle control device 110 will be described.

[0013] The first in-vehicle control device 10 is composed of a semiconductor relay device 20 and a first control unit 30. A current is input to the semiconductor relay device 20 from a power supply (not shown). Then, the semiconductor relay device 20 controls the amount of current of the current output to the second in-vehicle control device 110. When the semiconductor relay device 20 is operating normally, a current is output to the second in-vehicle control device 110 with an appropriate amount of current. On the other hand, when an abnormality occurs in the semiconductor relay device 20, an excessive current is output to the second in-vehicle control device 110. Therefore, the first control unit 30 diagnoses the operation of the semiconductor relay device 20.

[0014] The first control unit (the first control unit 30) self-diagnoses a failure of the semiconductor relay device (the semiconductor relay device 20) based on a comparison result of comparing a first current value of the current flowing through the first in-vehicle control device (the first in-vehicle control device 10) with a second current value of the current flowing through the second in-vehicle control device (the second in-vehicle control device 110). As shown in FIG. 3 described later, the first control unit (the first control unit 30) transmits a request signal for requesting measurement (monitoring) of the current flowing through the second in-vehicle control device (the second in-vehicle control device 110) to the second control unit (the second control unit 130).

[0015] The first control unit 30 includes a first communication unit 40, a first current value acquisition unit 50, a second current value acquisition unit 60, a comparison unit 70, and a diagnosis unit 80. The first communication unit 40 is communicable with the second communication unit 150 of the second in-vehicle control device 110. And the first communication unit (the first communication unit 40) receives a second current value from the second in-vehicle control device (the second in-vehicle control device 110).

[0016] The first current value acquisition unit (the first current value acquisition unit 50) acquires, as a first current value, the current value of the current flowing from the semiconductor relay device (the semiconductor relay device 20) to the first in-vehicle control device (the first in-vehicle control device 10). The second current value acquisition unit (the second current value acquisition unit 60) acquires, as a second current value, the current value of the current flowing through the second in-vehicle control device (the second in-vehicle control device 110) from the first communication unit (the first communication unit 40).

[0017] The comparison unit (comparison unit 70) compares the first current value received from the first current value acquisition unit (first current value acquisition unit 50) with the second current value received from the second current value acquisition unit (second current value acquisition unit 60), and outputs a comparison result.

[0018] The diagnosis unit (diagnosis unit 80) diagnoses a failure of the semiconductor relay device (semiconductor relay device 20) based on the comparison result input from the comparison unit 70. For example, the diagnosis unit 80 diagnoses whether the semiconductor relay device 20 is normal or abnormal. When the diagnosis unit 80 determines that the semiconductor relay device 20 is abnormal, it performs processes such as stopping the operation of the semiconductor relay device 20.

[0019] The second in-vehicle control device (second in-vehicle control device 110) includes a second control unit (second control unit 130). The second control unit 130 controls the current output from the semiconductor relay device 20 to be output to a load (not shown) connected downstream of the second in-vehicle control device 110.

[0020] The second control unit 130 includes a measurement unit 140 and a second communication unit 150. The measurement unit (measurement unit 140) is located downstream of the semiconductor relay device 20 and measures a second current value of the current flowing through the second in-vehicle control device (second in-vehicle control device 110). The measurement of the second current value is performed at the timing when the second communication unit 150 receives a request signal. Then, the measurement unit 140 outputs the second current value, which is the measurement result, to the second communication unit 150.

[0021] The second communication unit (second communication unit 150) transmits the second current value obtained from the measurement unit (measurement unit 140) to the first communication unit (first communication unit 40). For example, the second communication unit (second communication unit 150) transmits the second current value of the current flowing through the second in-vehicle control device 110, which is measured by the measurement unit (measurement unit 140) in response to the request signal received from the first communication unit 40, to the first communication unit (first communication unit 40).

[0022] Next, an example of the processing of the first in-vehicle control device 10 on the upstream side and the second in-vehicle control device 110 on the downstream side according to the first embodiment will be described with reference to FIGS. 2 and 3. FIG. 2 is a flowchart showing an operation example of the first in-vehicle control device 10 and the second in-vehicle control device 110 according to the first embodiment. FIG. 3 is a time chart showing an operation example of the first in-vehicle control device 10 and the second in-vehicle control device 110 according to the first embodiment. In FIG. 3, the first current value measured by the first in-vehicle control device 10, the second current value measured by the second in-vehicle control device 110, and the communication timings of the first in-vehicle control device 10 and the second in-vehicle control device 110 are shown in order from the top.

[0023] First, the first control unit 30 transmits a current monitor request signal to the second control unit 130 through the first communication unit 40 (S1). At this time, at the communication timing T1 shown in FIG. 3, the current monitor request signal is transmitted from the first communication unit 40 of the first in-vehicle control device 10 to the second communication unit 150.

[0024] When the second communication unit 150 receives the current monitor request signal at the communication timing T2 shown in FIG. 3, the measurement unit 140 monitors the current value (second current value) of the current flowing through the second in-vehicle control device 110. Almost simultaneously with the communication timing T2, the first current value acquisition unit 50 of the first control unit 30 starts monitoring the current value (first current value) of the current flowing through the first in-vehicle control device 10 by acquiring the current value from the semiconductor relay device 20 (S2). The periods of the communication timings T1 and T2 are preset in consideration of the transmission time of the request signal and the like.

[0025] Next, the second communication unit 150 transmits the second current value monitored by the measurement unit 140 to the first communication unit 40 (S3). Then, the first communication unit 40 transmits the second current value received from the second communication unit 150 to the second current value acquisition unit 60 (S4).

[0026] The first control unit 30 compares the current value acquired by the first current value acquisition unit 50, that is, the first current value of the current flowing through the first in-vehicle control device 10, with the current value acquired by the second current value acquisition unit 60, that is, the second current value of the current flowing through the second in-vehicle control device 110, using the comparison unit 70. Then, the comparison unit 70 outputs the error between the first current value and the second current value to the diagnosis unit 80. The diagnosis unit 80 determines whether the error between the first current value and the second current value is within the range of the allowable value determined by the in-vehicle control device 1 (S5).

[0027] When the error between the first current value and the second current value is within the range of the allowable value (YES in S5), the diagnosis unit 80 determines that the semiconductor relay device 20 is not faulty. In this case, the process returns to step S1 and continues.

[0028] On the other hand, when the error between the first current value and the second current value is not within the range of the allowable value (NO in S5), the diagnosis unit 80 determines that the semiconductor relay device 20 is faulty (S6). In this case, the first control unit 30 may cut off the current flowing through the first in-vehicle control device 10 or notify other control devices of the failure of the semiconductor relay device 20.

[0029] Here, the hardware configuration of the computer 200 that constitutes each device of the in-vehicle control device 1 will be described. FIG. 4 is a block diagram showing an example of the hardware configuration of the computer 200. The computer 200 is an example of the hardware used as a computer that can operate as the first in-vehicle control device 10 and the second in-vehicle control device 110 according to the present embodiment. The first in-vehicle control device 10 and the second in-vehicle control device 110 according to the present embodiment realize the method for diagnosing the failure of the semiconductor relay device 20 in which each functional block shown in FIG. 1 cooperates by the computer 200 (computer) executing a program.

[0030] The computer 200 includes a CPU (Central Processing Unit) 210, a ROM (Read Only Memory) 220, and a RAM (Random Access Memory) 230, which are respectively connected to a bus 240. Further, the computer 200 includes a non-volatile storage 250 and a network interface 260.

[0031] The CPU 210 reads the program code of the software that realizes each function according to the present embodiment from the ROM 220, loads it into the RAM 230, and executes it. Variables, parameters, etc. generated during the arithmetic processing of the CPU 210 are temporarily written into the RAM 230, and these variables, parameters, etc. are appropriately read by the CPU 210. However, an MPU (Micro Processing Unit) may be used instead of the CPU 210. The functions of each part of the first control unit 30 and the second control unit 130 shown in FIG. 1 are realized by a program executed by the CPU 210.

[0032] As the non-volatile storage 250, for example, an HDD (Hard Disk Drive), an SSD (Solid State Drive), an optical disk, a magneto-optical disk, a CD-ROM, a CD-R, or a non-volatile memory, etc. are used. In this non-volatile storage 250, in addition to the OS (Operating System) and various parameters, a program for operating the computer 200 is recorded. The ROM 220 and the non-volatile storage 250 record programs, data, etc. necessary for the operation of the CPU 210, and are used as an example of a computer-readable non-transitory storage medium storing the programs executed by the computer 200. The allowable values shown in FIG. 2 are stored in the non-volatile storage 250 and are appropriately read by the CPU 210.

[0033] The network interface 260 uses, for example, a NIC (Network Interface Card) or the like, and it is possible to transmit and receive various data between devices via a LAN (Local Area Network), a dedicated line, or the like connected to the terminals of the NIC. The functions of the first communication unit 40 and the second communication unit 150 are realized by the network interface 260.

[0034] In the first in-vehicle control device 10 according to the first embodiment described above, whether or not the error between the first current value of the current flowing through the semiconductor relay device 20 and the second current value of the current flowing through the second in-vehicle control device 110 is within the allowable value range is determined, and a failure of the semiconductor relay device 20 is determined. For this reason, the first control unit 30 can detect a failure of the semiconductor relay device 20. As a result, when the semiconductor relay device 20 fails, the first control unit 30 can immediately cut off the semiconductor relay device 20, thereby avoiding an event in which excessive power is output downstream of the first in-vehicle control device 10.

[0035] Also, when the diagnostic unit 80 diagnoses that a failure has occurred in the semiconductor relay device 20, the failure of the semiconductor relay device 20 is promptly notified. For this reason, it is possible to stop power supply to the second in-vehicle control device 110, issue an alert to the driver, and the like.

[0036] When there are a plurality of downstream in-vehicle control devices such as the second in-vehicle control device and the third in-vehicle control device, in step S5 of FIG. 2, the first current value of the current flowing through the first in-vehicle control device 10 and the total value of the second current values of the currents flowing through the downstream in-vehicle control devices may be compared. Then, when the error between the first current value and the total value of the second current values is not within the allowable value range (NO in S5), the diagnostic unit 80 may determine that the semiconductor relay device 20 is faulty (S6).

[0037] [Second Embodiment] Next, an operation example of the in-vehicle control device 1 according to the second embodiment of the present invention will be described with reference to FIGS. 5 and 6.

[0038] The first control unit (the first control unit 30) according to the second embodiment transmits, from the first communication unit (the first communication unit 40), a request signal for requesting the start of measurement (monitoring) of the current flowing through the second in-vehicle control device (the second in-vehicle control device 110) to the second control unit (the second control unit 130), and a request signal for requesting the end of measurement (monitoring) of the current flowing through the second in-vehicle control device (the second in-vehicle control device 110) after a predetermined period. The first current value acquisition unit (the first current value acquisition unit 50) obtains the average value of the first current values acquired during the predetermined period, and the second current value acquisition unit (the second current value acquisition unit 60) obtains the average value of the second current values acquired during the predetermined period. Then, the comparison unit 70 (the comparison unit 70) outputs a comparison result of comparing the average value of the first current values with the average value of the second current values. A specific example of the process will be described below.

[0039] FIG. 5 is a flowchart showing an operation example of the first in-vehicle control device 10 and the second in-vehicle control device 110 according to the second embodiment. FIG. 6 is a timing chart showing an operation example of the first in-vehicle control device 10 and the second in-vehicle control device 110 according to the second embodiment. In FIG. 6, the first current value measured by the first in-vehicle control device 10, the second current value measured by the second in-vehicle control device 110, and the communication timings of the first in-vehicle control device 10 and the second in-vehicle control device 110 are shown in order from the top.

[0040] First, the first control unit 30 transmits a current monitor request signal to the second control unit 130 through the first communication unit 40 (S11). At this time, at the communication timing T11 shown in FIG. 6, a request signal for starting the current monitor is transmitted from the first communication unit 40 of the first in-vehicle control device 10 to the second communication unit 150.

[0041] At communication timing T12 shown in FIG. 6, when the second communication unit 150 receives a request signal for starting current monitoring, the measurement unit 140 starts monitoring the current value (second current value) of the current flowing through the second in-vehicle control device 110. Almost simultaneously with communication timing T12, the first current value acquisition unit 50 of the first control unit 30 starts monitoring the current value (first current value) of the current flowing through the first in-vehicle control device 10 by acquiring the current value from the semiconductor relay device 20 (S12). The periods of communication timings T11 and T12 are preset in consideration of the transmission time of the request signal and the like.

[0042] Next, the first control unit 30 transmits a request signal for ending current monitoring to the second control unit 130 through the first communication unit 40 (S13). At this time, at communication timing T13 shown in FIG. 6, a request signal for ending current monitoring is transmitted from the first communication unit 40 of the first in-vehicle control device 10 to the second communication unit 150.

[0043] At communication timing T14 shown in FIG. 6, when the second communication unit 150 receives a request signal for ending current monitoring, the measurement unit 140 ends monitoring the current value (second current value) of the current flowing through the second in-vehicle control device 110.

[0044] Almost simultaneously with communication timing T14, the first current value acquisition unit 50 of the first control unit 30 ends monitoring the current value (first current value) of the current flowing through the first in-vehicle control device 10 (S14). The periods of communication timings T13 and T14 are preset in consideration of the transmission time of the request signal and the like. After that, the first current value acquisition unit 50 divides the cumulative value of the first current values monitored during the current monitoring period by the current monitoring period to calculate the average value of the first current values.

[0045] Next, the second communication unit 150 transmits the cumulative value of the second current value monitored by the measurement unit 140 from the start to the end of monitoring to the first communication unit 40 (S15). After that, the first communication unit 40 transmits the received cumulative value of the second current value to the second current value acquisition unit 60 (S16). Then, the second current value acquisition unit 60 divides the cumulative value of the second current value monitored during the current monitor period by the current monitor period (the period of communication timings T12 to T14) to calculate the average value of the second current value per unit time.

[0046] Next, the comparison unit 70 compares the average value of the first current value acquired by the first current value acquisition unit 50, that is, the average value of the first current value of the current flowing through the first in-vehicle control device 10, with the average value of the second current value acquired by the second current value acquisition unit 60, that is, the average value of the second current value of the current flowing through the second in-vehicle control device 110. Then, the comparison unit 70 outputs the error between the average value of the first current value and the average value of the second current value. The diagnosis unit 80 determines whether the error between the average value of the first current value and the average value of the second current value is within the range of the allowable value determined by the in-vehicle control device 1 (S17).

[0047] When the error between the average value of the first current value and the average value of the second current value is within the range of the allowable value (YES in S17), the diagnosis unit 80 determines that the semiconductor relay device 20 is not faulty. In this case, the process returns to step S11 and continues.

[0048] On the other hand, when the error between the average value of the first current value and the average value of the second current value is not within the range of the allowable value determined by the in-vehicle control device 1 (NO in S17), the diagnosis unit 80 determines that the semiconductor relay device 20 is faulty (S18). In this case, the first control unit 30 cuts off the current flowing through the first in-vehicle control device 10. Also, the first control unit 30 may notify other control devices of the failure of the semiconductor relay device 20.

[0049] In the first vehicle-mounted control device 10 according to the second embodiment described above, whether a failure of the semiconductor relay device 20 is determined depends on whether the error between the average value of the first current value of the current flowing through the semiconductor relay device 20 and the average value of the second current value of the current flowing through the second vehicle-mounted control device 110 is within the allowable value range. Therefore, even if a large error occurs due to a temporary change in the first current value and the second current value, the influence of the error can be suppressed by taking the average. When it is determined that a failure has occurred in the semiconductor relay device 20, the failure of the semiconductor relay device 20 is promptly notified, so that it is possible to stop the power supply to the second vehicle-mounted control device 110, issue an alert to the driver, and the like.

[0050] When there are a plurality of downstream vehicle-mounted control devices such as the second vehicle-mounted control device and the third vehicle-mounted control device, in step S17 of FIG. 5, the average value of the first current value and the total value of the average values of the second current values may be compared. When the error between the average value of the first current value and the total value of the second current values is not within the allowable value range (NO in S17), the diagnostic unit 80 may determine that the semiconductor relay device 20 has failed (S16).

[0051] Note that the present invention is not limited to the above-described embodiments, and it goes without saying that various other application examples and modification examples can be adopted without departing from the gist of the present invention described in the claims. For example, the above-described embodiments have described the configuration of the device in detail and specifically in order to explain the present invention in an easy-to-understand manner, and are not necessarily limited to those having all the configurations described. Also, it is possible to replace a part of the configuration of the embodiment described here with the configuration of another embodiment, and further, it is possible to add the configuration of another embodiment to the configuration of an embodiment. Also, it is possible to add, delete, or replace a part of the configuration of each embodiment with another configuration. In addition, the control lines and information lines show those considered necessary for explanation, and do not necessarily show all the control lines and information lines on the product. In fact, it may be considered that almost all the components are interconnected.

Explanation of Reference Numerals

[0052] 1…Vehicle control device, 10…First vehicle control device, 20…Semiconductor relay device, 30…First control unit, 40…First communication unit, 50…First current value acquisition unit, 60…Second current value acquisition unit, 70…Comparison unit, 80…Diagnosis unit, 110…Second vehicle control device, 130…Second control unit, 140…Measurement unit, 150…Second communication unit

Claims

1. A first in-vehicle control device having a semiconductor relay device and a first control unit; At least one second in-vehicle control device connected to the downstream side of the semiconductor relay device; Comprising: The first control unit includes a first current value acquisition unit that acquires a first current value of a current flowing through the semiconductor relay device from the semiconductor relay device; A first communication unit that receives a second current value from the second in-vehicle control device; A second current value acquisition unit that acquires the second current value from the first communication unit; A comparison unit that compares the first current value received from the first current value acquisition unit with the second current value received from the second current value acquisition unit and outputs a comparison result; A diagnostic unit that self-diagnoses a failure of the semiconductor relay device based on the comparison result. In-vehicle control device.

2. The second in-vehicle control device has a second control unit, The second control unit includes a measurement unit that measures the second current value, A second communication unit that transmits the second current value obtained from the measurement unit to the first communication unit. The in-vehicle control device according to claim 1.

3. The first control unit transmits a request signal to the second control unit to request measurement of the current flowing through the second in-vehicle control device, The second communication unit transmits the second current value measured by the measurement unit to the first communication unit in response to the request signal. The in-vehicle control device according to claim 2.

4. The first control unit transmits, from the first communication unit, a request signal for requesting start of measurement of the current flowing through the second in-vehicle control device and a request signal for requesting end of measurement of the current flowing through the second in-vehicle control device after a predetermined period to the second control unit, The first current value acquisition unit obtains an average value of the first current values acquired during the predetermined period, The second current value acquisition unit obtains an average value of the second current values acquired during the predetermined period, The comparison unit outputs a comparison result obtained by comparing the average value of the first current values with the average value of the second current values. The in-vehicle control device according to claim 2.

5. A method for diagnosing a failure of a semiconductor relay device performed by an in-vehicle control device including a first in-vehicle control device having a semiconductor relay device and a first control unit, and at least one second in-vehicle control device connected to the downstream side of the semiconductor relay device, A step in which a first current value acquisition unit included in the first control unit acquires a first current value of a current flowing through the semiconductor relay device from the semiconductor relay device; A step in which a first communication unit included in the first control unit receives a second current value from the second in-vehicle control device; A step in which a second current value acquisition unit included in the first control unit acquires the second current value from the first communication unit; A step in which a comparison unit included in the first control unit compares the first current value received from the first current value acquisition unit with the second current value received from the second current value acquisition unit and outputs a comparison result; A step in which a diagnosis unit included in the first control unit self-diagnoses a failure of the semiconductor relay device based on the comparison result, and includes A fault diagnosis method.

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