Vehicular diagnosis device

Abstract

To provide a vehicular diagnosis device capable of finding a potential abnormality of a sensor at an early stage.SOLUTION: A vehicular diagnosis device includes: a sensor signal obtaining unit (an obtaining unit) that obtains a sensor signal output by a sensor installed in a vehicle; a first sensor signal level determining unit (a first determining unit) that determines whether or not the sensor that outputs the sensor signal is abnormal by comparing the level of the sensor signal obtained by the sensor signal obtaining unit with a first threshold; a second sensor signal level determining unit (a second determining unit) that determines whether or not the level of the sensor signal is in between a second threshold set at a state before a transition from a normal state to an abnormal state and the first threshold; and a sensor signal storing unit (a storing unit) that stores, if the second sensor signal level determining unit determines that the level of the sensor signal is in between the first threshold and the second threshold, the sensor signal by what corresponds to a predetermined time including the current time.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a vehicle diagnostic device. [Background technology]

[0002] Various sensors are mounted on vehicles to appropriately control the engine, chassis, brakes, steering, etc. Devices that detect abnormalities in sensors have been put to practical use to monitor whether these sensors are operating normally.

[0003] For example, Patent Document 1 discloses a sensor abnormality detection device that outputs an alarm to a driver when an abnormality occurs in a sensor. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2006-240453 A Summary of the Invention [Problem to be solved by the invention]

[0005] The sensor anomaly detection device disclosed in Patent Document 1 obtains information indicating that an abnormality has occurred in the sensor at the time when the sensor anomaly is confirmed, and therefore cannot detect potential anomalies that exist immediately before the anomaly is confirmed.

[0006] An object of the present invention is to provide a vehicle diagnostic device capable of detecting a potential abnormality in a sensor at an early stage. [Means for solving the problem]

[0007] In order to achieve the above-mentioned object, the vehicle diagnosis device of the present invention comprises an acquisition unit that acquires a sensor signal output by a sensor installed in a vehicle, a first judgment unit that judges whether the sensor outputting the sensor signal is abnormal by comparing a magnitude of the sensor signal acquired by the acquisition unit with a first threshold, a second judgment unit that judges whether the magnitude of the sensor signal is between the first threshold and a second threshold set just before a transition from a normal state to an abnormal state, and a memory unit that stores the sensor signal for a predetermined period of time including a current time when the second judgment unit judges that the magnitude of the sensor signal is between the first threshold and the second threshold.

[0008] This configuration allows potential abnormalities in the sensor to be detected at an early stage.

[0009] In addition, in the vehicle diagnosis device of the present invention, when the second determination unit determines that the magnitudes of the sensor signals output by the same sensor in a plurality of consecutive driving states of the vehicle are all between the first threshold value and the second threshold value, the memory unit stores the sensor signals for a predetermined period of time including the current time.

[0010] According to this configuration, if a potential abnormality is detected in the sensor signal in all of a plurality of consecutive driving cycles, it is possible to determine that the sensor signal has a potential abnormality.

[0011] Furthermore, in the vehicle diagnosis device according to the present invention, when the second determination unit determines that the magnitude of the sensor signal is between the first threshold value and the second threshold value, the memory unit stores time series data of the sensor signal for a predetermined time period including a current time, time series data of a vehicle state of the vehicle at that time, and time series data of driving operation information of the driver, in association with each other by time.

[0012] According to this configuration, along with the sensor signal, it is possible to obtain vehicle state and driving operation information that is associated with the sensor signal by time, thereby making it possible to analyze the relationship between the vehicle behavior and driving operation and potential abnormalities in the sensor.

[0013] The vehicle diagnosis device according to the present invention further includes a sensor signal output unit that outputs the data stored in the memory unit together with information that uniquely identifies the vehicle to the outside of the vehicle via a communication line.

[0014] According to this configuration, the sensor signal acquired when it is determined that there is a potential abnormality can be read out and analyzed, thereby making it possible to analyze the cause of the potential abnormality. Effect of the Invention

[0015] According to the present invention, a potential abnormality in a sensor can be detected at an early stage. [Brief description of the drawings]

[0016] [Figure 1] FIG. 1 is a block diagram showing an example of a functional configuration of a vehicle diagnosis device according to a first embodiment. [Diagram 2] FIG. 2 is a first diagram illustrating a method in which the vehicle diagnosis device according to the first embodiment detects a potential abnormality in a sensor. [Diagram 3] FIG. 3 is a second diagram illustrating the method in which the vehicle diagnosis device according to the first embodiment detects a potential abnormality in a sensor. [Figure 4] FIG. 4 is a flowchart showing an example of a flow of processing performed by the vehicle diagnosis device of the first embodiment. [Diagram 5] FIG. 5 is a block diagram showing an example of a functional configuration of a vehicle diagnosis device according to the second embodiment. [Figure 6] FIG. 6 is a flowchart showing an example of a flow of processing performed by the vehicle diagnosis device of the second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0018] (First embodiment) A schematic configuration of a vehicle diagnosis device according to a first embodiment of the present invention will be described with reference to Fig. 1. Fig. 1 is a block diagram showing an example of a functional configuration of the vehicle diagnosis device according to the first embodiment.

[0019] (General configuration of vehicle diagnostic device) The vehicle diagnostic device 10 is mounted on a vehicle (not shown) and detects potential abnormalities in various sensors 20 installed in the vehicle.

[0020] The sensor 20 is, for example, a sensor that detects various physical quantities in order to perform various controls related to the engine of the vehicle. For example, the sensor 20 is a water temperature sensor that detects the temperature of cooling water, an intake pressure sensor that detects the intake pressure, an intake air temperature sensor that detects the intake air temperature, a throttle position sensor that detects the depression angle of the accelerator pedal, an oxygen sensor that detects the oxygen concentration, etc. The sensor 20 is not limited to a sensor related to engine control, and may be a sensor related to brake control, a sensor related to transmission control, or a sensor related to driving control such as ADAS (Advanced Driver-Assistance Systems).

[0021] 1, the vehicle diagnostic device 10 includes an ECU 12a, a sensor signal memory 14, a warning light 22, a fault diagnosis device 24, and a wireless communication interface 26. In addition, a plurality of sensors 20 are connected to the ECU 12a via an in-vehicle LAN 16 such as a CAN (Control Area Network).

[0022] The ECU 12a is a processor configured as a computer, and operates in accordance with a control program stored in the ECU 12a to cause the vehicle diagnosis device 10 to perform a predetermined operation.

[0023] By executing the control program, the ECU 12a realizes as functional units the sensor signal acquisition unit 121, the first sensor signal level determination unit 122, the second sensor signal level determination unit 123, the warning light illumination control unit 124, the sensor signal memory unit 125, the vehicle state acquisition unit 126, the driving operation information acquisition unit 127, the memory information output unit 128, the setting information acquisition unit 129, and the fail-safe control unit 130 shown in FIG. 1.

[0024] The sensor signal acquisition unit 121 acquires a sensor signal S(t) output by a sensor 20 installed in a vehicle. The sensor signal S(t) is, for example, a voltage value. The sensor signal acquisition unit 121 is an example of an acquisition unit in the present disclosure.

[0025] The first sensor signal level determination unit 122 compares the magnitude of the sensor signal S(t) acquired by the sensor signal acquisition unit 121 with a threshold value Th1 to determine whether an abnormality has occurred in the sensor 20 that outputs the sensor signal S(t). Specifically, the first sensor signal level determination unit 122 determines that an abnormality has occurred in the sensor 20 that outputs the sensor signal S(t) when the magnitude of the sensor signal S(t) is equal to or greater than the threshold value Th1 (as in FIG. 2, which will be described later) or when the magnitude of the sensor signal S(t) is equal to or less than the threshold value Th1 (as in FIG. 3, which will be described later). The first sensor signal level determination unit 122 is an example of a first determination unit in the present disclosure. The threshold value Th1 is an example of a first threshold value in the present disclosure.

[0026] The second sensor signal level determination unit 123 determines whether the magnitude of the sensor signal S(t) acquired by the sensor signal acquisition unit 121 is between a threshold Th2 and a threshold Th1 set just before the transition from a normal state to an abnormal state. The second sensor signal level determination unit 123 is an example of a second determination unit in the present disclosure. The threshold Th2 is an example of a second threshold in the present disclosure.

[0027] When it is determined that there is an abnormality in the sensor signal S(t) output by the sensor 20, the warning light illumination control unit 124 issues a notification by turning on the warning light 22.

[0028] When the second sensor signal level determination unit 123 determines that the magnitude of the sensor signal S(t) is between the threshold value Th1 and the threshold value Th2, the sensor signal storage unit 125 stores the sensor signal S(t) for a predetermined time period including the current time in the sensor signal memory 14 together with information for identifying the sensor 20, for example, an identifier uniquely assigned to the sensor 20. The predetermined time period is set according to the storage capacity of the sensor signal memory 14, etc. The sensor signal storage unit 125 is an example of a storage unit in the present disclosure.

[0029] In addition, when the first sensor signal level determination unit 122 determines that an abnormality has occurred in the sensor 20 that outputs the sensor signal S(t), the sensor signal storage unit 125 stores the sensor signal S(t) for a predetermined period of time including the current time in the sensor signal memory 14.

[0030] The vehicle state acquisition unit 126 acquires, via the in-vehicle LAN 16, information relating to the vehicle state, such as the state of the vehicle's ignition switch, the value of the odometer, the vehicle speed, the steering angle, the acceleration, the deceleration, and the like.

[0031] The driving operation information acquisition unit 127 acquires information related to driving operations such as the accelerator opening, the brake depression force, the steering amount, and the steering speed of the vehicle via the in-vehicle LAN 16.

[0032] The stored information output unit 128 outputs the data stored in the sensor signal storage unit 125 from the vehicle via a communication line together with identification information that uniquely identifies the vehicle. Note that the stored information output unit 128 is an example of a sensor signal output unit in the present disclosure.

[0033] The setting information acquisition unit 129 acquires various setting information related to the vehicle diagnosis device 10 from an external server device or the like via the wireless communication interface 26 .

[0034] When it is determined that the sensor 20 has an abnormality, the fail-safe control unit 130 causes the system related to the sensor 20 to perform a predetermined fail-safe operation.

[0035] The sensor signal memory 14 stores the sensor signal S(t) in accordance with an instruction from the sensor signal storage unit 125. The sensor signal memory 14 also stores information related to the vehicle state acquired by the vehicle state acquisition unit 126 and information related to the driving operation acquired by the driving operation information acquisition unit 127 in association with the sensor signal S(t) by time. The sensor signal memory 14 is a non-volatile memory such as a flash memory that retains stored information even when the power is turned off.

[0036] The warning light 22 is an indicator that turns on when it is determined that there is an abnormality in the sensor 20. The warning light 22 is installed in, for example, a meter cluster of the vehicle.

[0037] The fault diagnosis device 24 is a scan tool that is connected to the ECU 12a by wired communication and reads out and analyzes various pieces of information stored in the sensor signal memory 14.

[0038] The wireless communication interface 26 is an interface for performing wireless communication between the ECU 12a and an external server device, etc. The vehicle diagnostic device 10 acquires various setting information of the vehicle diagnostic device 10 by performing wireless communication with the external server device, etc. via the wireless communication interface 26. In addition, the vehicle diagnostic device 10 outputs various information stored in the sensor signal memory 14 to the outside by performing wireless communication with the external server device, etc. via the wireless communication interface 26.

[0039] 1, the ECU 12a further stores a table showing a list of the sensors 20 to be monitored. The ECU 12a also stores, for each sensor 20, a threshold value Th1, a threshold value Th2, etc. for determining the magnitude of the sensor signal S(t) of each sensor 20.

[0040] (Method of detecting potential abnormalities) A method in which the vehicle diagnostic device 10 detects a potential abnormality in the sensor 20 will be described with reference to Figures 2 and 3. Figure 2 is a first diagram for explaining a method in which the vehicle diagnostic device of the first embodiment detects a potential abnormality in the sensor. Figure 3 is a second diagram for explaining a method in which the vehicle diagnostic device of the first embodiment detects a potential abnormality in the sensor.

[0041] The sensor 20 outputs a time-series sensor signal S(t) as shown in Fig. 2. When the sensor 20 is operating normally, the sensor signal S(t) outputs a value less than a preset threshold value Th1. When an abnormality occurs in the sensor 20, such as a breakdown of the sensor itself or a break in the circuit that acquires the signal from the sensor 20, the sensor signal S(t) outputs a value greater than the threshold value Th1.

[0042] A conventional vehicle diagnostic device detects that an abnormality has occurred in the sensor 20 by detecting that the sensor signal S(t) outputs a value equal to or greater than the threshold value Th1.

[0043] In contrast, the vehicle diagnosis device 10 of this embodiment determines that a potential abnormality has occurred in the sensor 20 when the magnitude of the sensor signal S(t) is equal to or greater than a threshold value Th2 set immediately before the transition from a normal state to an abnormal state and is less than a threshold value Th1. A potential abnormality is a state requiring attention in which no abnormality has occurred at that point in time, but there are signs that an abnormality may occur.

[0044] 2, the vehicle diagnostic device 10 determines that the sensor 20 is operating normally before time t1. The vehicle diagnostic device 10 also determines that a potential abnormality has occurred in the sensor 20 between time t1 and time t2. Then, the vehicle diagnostic device 10 determines that an abnormality has occurred in the sensor 20 after time t2.

[0045] 2, a margin W shown in Fig. 2 is set between threshold value Th1 and threshold value Th2. The size of the margin W is appropriately set depending on the results of advance consideration, etc.

[0046] Moreover, the output characteristics of the sensor 20 are not limited to the example shown in Fig. 2. Fig. 3 shows another example of the output characteristics of the sensor 20.

[0047] 3, when the sensor 20 is operating normally, the sensor signal S(t) outputs a value that exceeds a preset threshold value Th1. When an abnormality occurs in the sensor 20, such as a breakdown of the sensor itself or a break in the circuit that acquires the signal of the sensor 20, the sensor signal S(t) outputs a value that is equal to or less than the threshold value Th1.

[0048] The vehicle diagnosis device 10 of this embodiment determines that a potential abnormality has occurred in the sensor 20 when the magnitude of the sensor signal S(t) is equal to or less than a threshold value Th2 set just before the transition from a normal state to an abnormal state and exceeds a threshold value Th1.

[0049] 3, the vehicle diagnostic device 10 determines that the sensor 20 is operating normally before time t3. The vehicle diagnostic device 10 also determines that a potential abnormality has occurred in the sensor 20 between time t3 and time t4. Then, the vehicle diagnostic device 10 determines that an abnormality has occurred in the sensor 20 after time t4.

[0050] 3, a margin W shown in FIG 3 is set between threshold value Th1 and threshold value Th2. The size of the margin W is appropriately set according to the results of advance consideration, etc.

[0051] (Flow of processing performed by the vehicle diagnostic device) The flow of processing performed by the vehicle diagnosis device 10 will be described with reference to Fig. 4. Fig. 4 is a flowchart showing an example of the flow of processing performed by the vehicle diagnosis device of the first embodiment. Fig. 4 shows the flow of processing when the acquired sensor signal S(t) has the characteristics shown in Fig. 2. When the acquired sensor signal S(t) has the characteristics shown in Fig. 3, the part of the flowchart that judges the magnitude relationship is changed to correspond to Fig. 3.

[0052] The vehicle state acquisition unit 126 determines whether the vehicle's ignition switch has been turned on (step S11). If it is determined that the vehicle's ignition switch has been turned on (step S11: Yes), the process proceeds to step S12. On the other hand, if it is not determined that the vehicle's ignition switch has been turned on (step S11: No), the determination of step S11 is repeated. Note that in the case where the vehicle is an electric vehicle, it is determined whether the main switch has been turned on instead of the ignition switch.

[0053] When it is determined in step S11 that the vehicle ignition switch has been turned on, the sensor signal acquisition unit 121 acquires the sensor signal S(t) output by the sensor 20 (step S12). Here, not only a specific sensor 20 but multiple sensor signals S(t) output by multiple sensors 20 are acquired. At this time, the sensor signal acquisition unit 121 acquires the sensor signal S(t) after identifying which sensor 20 the sensor signal S(t) is output from.

[0054] The first sensor signal level determination unit 122 determines whether the magnitude of the sensor signal S(t) is equal to or greater than the threshold Th1 (step S13). If it is determined that the magnitude of the sensor signal S(t) is equal to or greater than the threshold Th1 (step S13: Yes), the process proceeds to step S14. On the other hand, if it is not determined that the magnitude of the sensor signal S(t) is equal to or greater than the threshold Th1 (step S13: No), the process proceeds to step S17.

[0055] If it is determined in step S13 that the magnitude of the sensor signal S(t) is equal to or greater than the threshold value Th1, the vehicle diagnosis device 10 determines that an abnormality has occurred in the corresponding sensor 20. Then, the warning light illumination control unit 124 turns on the warning light 22 (step S14).

[0056] The sensor signal storage unit 125 stores the acquired sensor signal S(t), the vehicle state information acquired by the vehicle state acquisition unit 126, and the driving operation information acquired by the driving operation information acquisition unit 127 in the sensor signal memory 14 for a predetermined period of time (step S15).

[0057] The fail-safe control unit 130 performs a predetermined fail-safe control when an abnormality occurs in the corresponding sensor 20 (step S16), and then the process proceeds to step S19.

[0058] On the other hand, if it is not determined in step S13 that the magnitude of the sensor signal S(t) is equal to or greater than the threshold Th1, the second sensor signal level determination unit 123 determines whether the magnitude of the sensor signal S(t) is equal to or greater than the threshold Th2 and less than the threshold Th1 (step S17). If it is determined that the magnitude of the sensor signal S(t) is equal to or greater than the threshold Th2 and less than the threshold Th1 (step S17: Yes), the process proceeds to step S18. On the other hand, if it is not determined that the magnitude of the sensor signal S(t) is equal to or greater than the threshold Th2 and less than the threshold Th1 (step S17: No), the process proceeds to step S19.

[0059] If it is determined in step S17 that the magnitude of the sensor signal S(t) is equal to or greater than the threshold Th2 and less than the threshold Th1, the vehicle diagnosis device 10 determines that a potential abnormality has occurred in the corresponding sensor 20. Then, the sensor signal storage unit 125 stores the acquired sensor signal S(t), the vehicle state information acquired by the vehicle state acquisition unit 126, and the driving operation information acquired by the driving operation information acquisition unit 127 in the sensor signal memory 14 for a predetermined period of time (step S18). Then, the process proceeds to step S19.

[0060] In step S17, if it is not determined that the magnitude of the sensor signal S(t) is equal to or greater than the threshold value Th2 and less than the threshold value Th1, and following steps S14 and S18, the vehicle state acquisition unit 126 determines whether the vehicle's ignition switch has been turned off (step S19). If it is determined that the vehicle's ignition switch has been turned off (step S19: Yes), the vehicle diagnosis device 10 ends the process of FIG. 4. On the other hand, if it is not determined that the vehicle's ignition switch has been turned off (step S19: No), the process returns to step S12 and repeats the above-mentioned process. Note that if the vehicle is an electric vehicle, it is determined whether the main switch has been turned off instead of the ignition switch.

[0061] Although not shown in the flowchart of Fig. 4, when the vehicle diagnosis device 10 determines an abnormality in the sensor 20 and when it determines a potential abnormality in the sensor 20, the stored information output unit 128 may output the sensor signal S(t) for a predetermined time period stored in the sensor signal memory 14, the vehicle state information, and the driving operation information to an external server device or the like via the wireless communication interface 26. When the vehicle is brought into a repair shop and the fault diagnosis device 24 is connected, the stored information output unit 128 may output the sensor signal S(t) for a predetermined time period stored in the sensor signal memory 14, the vehicle state information, and the driving operation information to the fault diagnosis device 24. This allows the contents and causes of abnormalities and potential abnormalities that have occurred during driving to be analyzed in detail by an external server device or the like.

[0062] Furthermore, the setting information acquisition unit 129 included in the ECU 12a may acquire values ​​of internal parameters of the vehicle diagnostic device 10 via the wireless communication interface 26. For example, the threshold value Th2 and the margin W described above may be changed to more appropriate values ​​based on the analysis results of a server device or the like external to the vehicle diagnostic device 10. Since the vehicle diagnostic device 10 can acquire values ​​of internal parameters via the wireless communication interface 26, it is possible to reliably change the values ​​of internal parameters of an unspecified number of vehicles in a short period of time.

[0063] (Effects of the first embodiment) As described above, the vehicle diagnosis device 10 of the first embodiment includes a sensor signal acquisition unit 121 (acquisition unit) that acquires a sensor signal S(t) output by a sensor 20 installed in a vehicle, a first sensor signal level determination unit 122 (first determination unit) that determines whether the sensor 20 outputting the sensor signal S(t) is abnormal by comparing the magnitude of the sensor signal S(t) acquired by the sensor signal acquisition unit 121 with a threshold value Th1 (first threshold value), a second sensor signal level determination unit 123 (second determination unit) that determines whether the magnitude of the sensor signal S(t) is between the threshold value Th1 and a threshold value Th2 (second threshold value) that is set on the side before the transition from a normal state to an abnormal state, and a sensor signal storage unit 125 (storage unit) that stores the sensor signal S(t) for a predetermined time period including the current time when the second sensor signal level determination unit 123 determines that the magnitude of the sensor signal S(t) is between the threshold value Th1 and the threshold value Th2. Therefore, a potential abnormality of the sensor can be found early.

[0064] In the vehicle diagnosis device 10 of the first embodiment, when the second sensor signal level determination unit 123 (second determination unit) determines that the magnitude of the sensor signal S(t) is between the threshold value Th1 (first threshold value) and the threshold value Th2 (second threshold value), the sensor signal storage unit 125 (storage unit) stores the sensor signal S(t) for a predetermined time period including the current time, the vehicle state information at that time, and the driver's driving operation information in association with time. Therefore, it is possible to obtain the sensor signal S(t) as well as the vehicle state and driving operation information associated with the sensor signal S(t) at time t, and therefore it is possible to analyze the relationship between the behavior of the vehicle, the way the vehicle is used, and the potential abnormality of the sensor 20. This makes it possible to perform a cause analysis of the occurrence of the potential abnormality of the sensor 20.

[0065] Moreover, the vehicle diagnosis device 10 of the first embodiment further includes a stored information output unit 128 (sensor signal output unit) that outputs the data stored in the sensor signal storage unit 125 (storage unit) from the vehicle via a communication line together with identification information that uniquely identifies the vehicle. Therefore, the cause of the potential abnormality can be analyzed by reading and analyzing the sensor signal S(t) acquired when it is determined that there is a potential abnormality.

[0066] Second Embodiment A schematic configuration of a vehicle diagnosis device 11 according to a second embodiment of the present invention will be described with reference to Fig. 5. Fig. 5 is a block diagram showing an example of a functional configuration of the vehicle diagnosis device according to the second embodiment.

[0067] The vehicle diagnostic device 10 described in the first embodiment determines the occurrence of a potential abnormality in the sensor 20 that outputs the sensor signal S(t) by comparing the sensor signal S(t) with the thresholds Th1 and Th2 once. However, depending on the type of the sensor 20, it may be desirable to determine that a potential abnormality has occurred when the sensor signal S(t) continues to stay between the thresholds Th1 and Th2 for a predetermined period. The vehicle diagnostic device 11 of the second embodiment has a function of determining the occurrence of a potential abnormality when it is determined that a potential abnormality has occurred in all of a predetermined number of driving cycles. Note that a driving cycle is a period from when the ignition switch of the vehicle is turned on to when the ignition switch is turned off. Hereinafter, a driving cycle is simply referred to as a trip. Note that, in the case of an electric vehicle, the occurrence of a trip is determined by turning on and off a main switch instead of the ignition switch.

[0068] 5 instead of the ECU 12a included in the vehicle diagnostic device 10. The rest of the configuration of the vehicle diagnostic device 11 is the same as that of the vehicle diagnostic device 10.

[0069] The ECU 12b is a processor having a computer configuration, and operates in accordance with a control program stored in the ECU 12b to cause the vehicle diagnosis device 11 to perform a predetermined operation.

[0070] The ECU 12b includes a potential abnormality determination history storage unit 131 in addition to the functional units included in the ECU 12a of the vehicle diagnosis device 10.

[0071] The potential abnormality determination history storage unit 131 stores information indicating whether a potential abnormality occurred in the sensor signal S(t) output by the sensor 20 in a past trip. The potential abnormality determination history storage unit 131 stores whether a potential abnormality occurred in the sensor signal S(t) output by the sensor 20 in a past trip by using a value of a potential abnormality determination flag F described later. The vehicle diagnostic device 11 presets a trip count corresponding to a predetermined number of times for a sensor among the sensors 20 that will determine a potential abnormality when a potential abnormality occurs in any of the sensors over a predetermined number of trips. The vehicle diagnostic device 11 increments the potential abnormality determination flag F once per trip each time a potential abnormality occurs in the sensor 20. Then, when the incremented potential abnormality determination flag F reaches a predetermined number of times, the vehicle diagnostic device 11 determines that a potential abnormality has occurred in the sensor 20.

[0072] (Flow of processing performed by the vehicle diagnostic device) The flow of processing performed by the vehicle diagnosis device 11 will be described with reference to Fig. 6. Fig. 6 is a flowchart showing an example of the flow of processing performed by the vehicle diagnosis device of the second embodiment. Fig. 6 shows the flow of processing when the acquired sensor signal S(t) has the characteristic shown in Fig. 2. When the acquired sensor signal S(t) has the characteristic shown in Fig. 3, the part of the flowchart that judges the magnitude relationship is changed to correspond to Fig. 3.

[0073] The vehicle state acquisition unit 126 determines whether the vehicle's ignition switch has been turned on (step S21). If it is determined that the vehicle's ignition switch has been turned on (step S21: Yes), the process proceeds to step S22. On the other hand, if it is not determined that the vehicle's ignition switch has been turned on (step S21: No), the determination of step S21 is repeated. Note that in the case where the vehicle is an electric vehicle, it is determined whether the main switch has been turned on instead of the ignition switch.

[0074] When it is determined in step S21 that the vehicle ignition switch has been turned on, the potential abnormality determination history storage unit 131 checks whether a potential abnormality was determined in the previous trip (step S22). If a potential abnormality was determined in the previous trip (step S22: Yes), the process proceeds to step S24. On the other hand, if a potential abnormality was not determined in the previous trip (step S22: No), the process proceeds to step S23.

[0075] If it is determined in step S22 that no potential abnormality occurred in the previous trip, the potential abnormality determination history storage unit 131 sets the potential abnormality determination flag F to 0 (step S23). Then, the process proceeds to step S24.

[0076] In step S22, if a potential abnormality was determined in the previous trip, or following step S23, the sensor signal acquisition unit 121 acquires the sensor signal S(t) output by the sensor 20 (step S24). Here, not only a specific sensor 20 but multiple sensor signals S(t) output by multiple sensors 20 are acquired. At this time, the sensor signal acquisition unit 121 acquires the sensor signal S(t) after identifying which sensor 20 output the sensor signal S(t).

[0077] The first sensor signal level determination unit 122 determines whether the magnitude of the sensor signal S(t) is equal to or greater than the threshold Th1 (step S25). If it is determined that the magnitude of the sensor signal S(t) is equal to or greater than the threshold Th1 (step S25: Yes), the process proceeds to step S26. On the other hand, if it is not determined that the magnitude of the sensor signal S(t) is equal to or greater than the threshold Th1 (step S25: No), the process proceeds to step S29.

[0078] If it is determined in step S25 that the magnitude of the sensor signal S(t) is equal to or greater than the threshold value Th1, the vehicle diagnosis device 10 determines that an abnormality has occurred in the corresponding sensor 20. Then, the warning light illumination control unit 124 turns on the warning light 22 (step S26). In other words, if the magnitude of the sensor signal S(t) has become equal to or greater than the threshold value Th1 even once, it is determined that an abnormality has occurred, regardless of the number of trips.

[0079] The sensor signal storage unit 125 stores the acquired sensor signal S(t), the vehicle state information acquired by the vehicle state acquisition unit 126, and the driving operation information acquired by the driving operation information acquisition unit 127 in the sensor signal memory 14 for a predetermined period of time (step S27).

[0080] The fail-safe control unit 130 performs a predetermined fail-safe control when an abnormality occurs in the corresponding sensor 20 (step S28), and then the process proceeds to step S34.

[0081] On the other hand, if it is not determined in step S25 that the magnitude of the sensor signal S(t) is equal to or greater than the threshold Th1, the second sensor signal level determination unit 123 determines whether the magnitude of the sensor signal S(t) is equal to or greater than the threshold Th2 and less than the threshold Th1 (step S29). If it is determined that the magnitude of the sensor signal S(t) is equal to or greater than the threshold Th2 and less than the threshold Th1 (step S29: Yes), the process proceeds to step S30. On the other hand, if it is not determined that the magnitude of the sensor signal S(t) is equal to or greater than the threshold Th2 and less than the threshold Th1 (step S29: No), the process proceeds to step S34.

[0082] If it is determined in step S29 that the magnitude of the sensor signal S(t) is equal to or greater than the threshold value Th2 and less than the threshold value Th1, the potential abnormality determination history storage unit 131 determines whether the sensor 20 has already been determined to have a potential abnormality in the current trip (step S30). If it is determined that the sensor 20 has already been determined to have a potential abnormality in the current trip (step S30: Yes), the process proceeds to step S34. On the other hand, if it is not determined that the sensor 20 has already been determined to have a potential abnormality in the current trip (step S30: No), the process proceeds to step S31.

[0083] If it is determined in step S30 that the sensor 20 has not already been determined to have a potential abnormality in the current trip, the potential abnormality determination history storage unit 131 increments the potential abnormality determination flag F (step S31).

[0084] Next, the potential abnormality determination history storage unit 131 determines whether the potential abnormality determination flag F is equal to a preset value (step S32). If it is determined that the potential abnormality determination flag F is equal to the preset value (step S32: Yes), the process proceeds to step S33. On the other hand, if it is not determined that the potential abnormality determination flag F is equal to the preset value (step S32: No), the process proceeds to step S34.

[0085] When it is determined in step S32 that the potential abnormality determination flag F is equal to the set value, the vehicle diagnosis device 10 determines that a potential abnormality has occurred in the corresponding sensor 20. Then, the sensor signal storage unit 125 stores the acquired sensor signal S(t), the vehicle state information acquired by the vehicle state acquisition unit 126, and the driving operation information acquired by the driving operation information acquisition unit 127 in the sensor signal memory 14 for a predetermined period of time (step S33). Then, the process proceeds to step S34.

[0086] If it is determined in step S29 that the magnitude of the sensor signal S(t) is not equal to or greater than the threshold value Th2 but less than the threshold value Th1, if it is determined in step S30 that the sensor 20 has already been potentially abnormal in the current trip, if it is determined in step S32 that the potential abnormality determination flag F is not equal to the set value, and following step S33, the vehicle state acquisition unit 126 determines whether the ignition switch of the vehicle has been turned off (step S34). If it is determined that the ignition switch of the vehicle has been turned off (step S34: Yes), the vehicle diagnosis device 10 ends the process of FIG. 6. On the other hand, if it is not determined that the ignition switch of the vehicle has been turned off (step S34: No), the process returns to step S24 and repeats the above-mentioned process. Note that if the vehicle is an electric vehicle, it is determined whether the main switch has been turned off instead of the ignition switch.

[0087] In addition, if the multiple sensors 20 installed in the vehicle include a sensor 20 for which it should be determined that a potential abnormality has occurred if the magnitude of the sensor signal S(t) falls between thresholds Th1 and Th2 even once, the sensor signal S(t) of that sensor 20 is processed according to the flowchart of Figure 4 described above.

[0088] (Effects of the second embodiment) As described above, in the vehicle diagnosis device 11 of the second embodiment, when the second sensor signal level determination unit 123 (second determination unit) determines that the magnitude of the sensor signal S(t) output by the same sensor 20 is between the threshold value Th1 (first threshold value) and the threshold value Th2 (second threshold value) in a plurality of consecutive driving states of the vehicle, the sensor signal storage unit 125 (storage unit) stores the sensor signal S(t) for a predetermined time period including the current time. Therefore, even if it is not possible to determine that a potential abnormality has occurred in the sensor signal S(t) in one trip, it is possible to determine that the sensor signal S(t) has a potential abnormality when it is determined that a potential abnormality exists over a plurality of trips.

[0089] Although the embodiment of the present invention has been described above, the above-mentioned embodiment is presented as an example and is not intended to limit the scope of the present invention. This new embodiment can be embodied in various other forms. In addition, various omissions, substitutions, and modifications can be made without departing from the gist of the invention. In addition, this embodiment is included in the scope and gist of the invention, and is included in the scope of the invention and its equivalents described in the claims. [Explanation of symbols]

[0090] 10,11 Vehicle diagnostic equipment 12a, 12b ECU 14 Sensor signal memory 20 Sensors 22 Warning light 121 Sensor signal acquisition unit (acquisition unit) 122 first sensor signal level determination unit (first determination unit) 123 Second sensor signal level determination unit (second determination unit) 125 Sensor signal storage unit (storage unit) 126 Vehicle status acquisition unit 127 Driving operation information acquisition unit 128 Memory information output unit (sensor signal output unit) 129 Setting information acquisition unit 130 Fail-safe control unit 131 Potential abnormality determination history memory unit S(t) Sensor signal Th1 threshold (first threshold) Th2 Threshold (Second Threshold) F Potential abnormality confirmation flag W margin

Claims

1. an acquisition unit that acquires a sensor signal output from a sensor installed in the vehicle; a first determination unit that determines whether a sensor that outputs a sensor signal is abnormal by comparing a magnitude of the sensor signal acquired by the acquisition unit with a first threshold; a second determination unit that determines whether a magnitude of the sensor signal is between a second threshold value that is set immediately before a transition from a normal state to an abnormal state and the first threshold value; a storage unit configured to store the sensor signal for a predetermined time period including a current time when the second determination unit determines that the magnitude of the sensor signal is between the first threshold value and the second threshold value. Vehicle diagnostic equipment.

2. When the second determination unit determines that the magnitudes of the sensor signals output from the same sensor in a plurality of consecutive driving states of the vehicle are all between the first threshold value and the second threshold value, The storage unit stores the sensor signal for a predetermined time period including a current time. The vehicle diagnostic device according to claim 1 .

3. The storage unit is when the second determination unit determines that the magnitude of the sensor signal is between the first threshold value and the second threshold value, the sensor signal for a predetermined time period including a current time, state information of the vehicle at that time, and driving operation information of the driver are stored in association with each other by time.

3. The vehicle diagnostic device according to claim 1 or 2.

4. a sensor signal output unit that outputs the data stored in the storage unit from the vehicle via a communication line together with identification information that uniquely identifies the vehicle.

3. The vehicle diagnostic device according to claim 1 or 2.

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