JP2010269635A - Diagnosis device for onboard equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To quickly discover a new failure factor caused during the maintenance work of a vehicle and a latent failure factor. <P>SOLUTION: Whether or not data of a backup RAM is normal is investigated (S2). When the data is not normal, a decision threshold is changed and set to an abnormality decision threshold easier to detect an abnormality than a normal time decision threshold (S5). Whether or not a normal decision is performed is investigated by a diagnosis using the abnormality decision threshold changed to easily detect the abnormality (S7). When the normal decision is performed, whether or not the normal decision is continued for a prescribed time is investigated (S8). When the normal decision is continued for the prescribed time, a normal time abnormality decision threshold is set (S3). As a result, the new failure factor caused during the maintenance work of the vehicle and a latent failure factor can be quickly discovered. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a diagnostic apparatus for an in-vehicle device that detects an abnormality in the in-vehicle device.

  A system of a vehicle such as an automobile is complicatedly electronically controlled, and when an abnormality occurs in the system, advanced knowledge and judgment are required to investigate the cause. For this reason, the on-board self-diagnosis function is provided in the electronic control system of the vehicle, and various proposals have been made so far in order to reliably detect a failure by this self-diagnosis.

  For example, in Patent Document 1, when a failure is determined by a continuation amount of an operating state where a failure precondition for a control device is satisfied exceeding a preset failure determination threshold value, a failure determination threshold value is based on the actual continuation amount. And a technique for preventing misjudgment due to individual differences such as variation between products of a vehicle is disclosed.

  Further, Patent Document 2 discloses a technique for preventing erroneous determination by changing the abnormality determination value of the engine control system so that the abnormality detection condition becomes looser during transient operation than during steady operation.

JP 2004-322740 A JP 2004-324416 A

  However, the conventional techniques disclosed in Patent Document 1 and Patent Document 2 are techniques for self-diagnosis of a failure while the user is using the vehicle, and the effects of vehicle inspection and maintenance are taken into consideration. Absent.

  That is, when a vehicle is serviced, some work is performed on the in-vehicle device, and since the device is in a serviced state, there is a possibility that other devices may be affected by a work error or the work. Also, during maintenance work, even equipment that is currently in the normal operating range will be damaged early after maintenance is completed and handed over to the user if it is near the normal range limit. There is a possibility, and it is preferable that a failure can be predicted in advance for such a device.

  The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide an in-vehicle device diagnostic apparatus capable of quickly finding a new failure factor or a potential failure factor that occurs during vehicle maintenance work. It is said.

  In order to achieve the above object, a diagnostic apparatus for an in-vehicle device according to the present invention monitors an operation of the in-vehicle device and detects an abnormality of the in-vehicle device by comparing with a predetermined diagnosis condition. A maintenance work detection unit that detects execution of maintenance work that may affect the operation of the in-vehicle device, and when the execution of the maintenance work is detected, the diagnosis condition is usually set for a predetermined set time. And a diagnostic condition changing unit for changing to a condition that makes it easier to detect an abnormality than the diagnostic condition.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to discover quickly the new failure factor and the potential failure factor which arise during the maintenance work of a vehicle, and can improve preventive safety.

Configuration diagram of vehicle control system Explanatory drawing showing the hydraulic control system of the hydraulic automatic transmission Functional block diagram of failure diagnosis system Flow chart of failure diagnosis processing

Embodiments of the present invention will be described below with reference to the drawings.
The in-vehicle device diagnosis apparatus according to the present invention includes various devices mounted on a vehicle, for example, various sensors for detecting a driving state, various actuators such as a hydraulic valve and a motor, display devices such as a meter and a display, etc. Failure diagnosis is performed on electronic devices such as devices and actuator driving devices. In the present embodiment, a description will be given focusing on an example in which a hydraulic automatic transmission in a vehicle drive system as shown in FIG.

  First, the vehicle drive system shown in FIG. 1 will be described. In the figure, reference numeral 1 denotes an engine 1, and a hydraulic automatic transmission 3 is connected to an output shaft of the engine 1 via a torque converter 2. The automatic transmission 3 is an automatic transmission having a plurality of shift speeds using a gear mechanism, or a winding type continuously variable transmission using a metal belt or chain. An oil pan for storing oil to be supplied to each mechanism part and engaging element of the torque converter and the power transmission mechanism is provided below the automatic transmission 3, and oil (pressure medium) supplied to each part is provided in this oil pan. The control valve body 3a in which various control valves for controlling the pressure are integrally formed is accommodated.

  As a control system for the engine 1 and the automatic transmission 3, an engine control unit 10 for controlling the engine 1 and a transmission control unit 20 for controlling the automatic transmission 3 through the control valve body 3a are provided. Area Network) are connected to each other via a network such as a bus 100. In addition to the engine control unit 10 and the transmission control unit 20, the CAN bus 100 includes vehicle controls such as a brake control unit 30 for brake control, a body control unit 40 for body system control such as a power window, a seat belt, and a door. A plurality of control units constituting the system are connected.

  Each control unit is composed mainly of a microcomputer, sends and receives control information to and from each other via the CAN bus 100, and sends out self-diagnosis information for devices controlled by each control unit onto the bus, causing an abnormality. In the case, the occurrence of abnormality is notified to other control units.

  For example, when the automatic transmission 3 is a winding type continuously variable transmission in which a metal belt, a chain, or the like is interposed between a primary pulley and a secondary pulley, a hydraulic pressure is set in order to secure a tension necessary for torque transmission. Control is performed so that the secondary pulley pressure by the cylinder becomes a predetermined target pressure. Specifically, the control of the secondary pulley pressure is executed by controlling the drive current of the actuator 6 formed of a linear solenoid that supplies oil to the hydraulic cylinder 4 via the passage 5 as shown in FIG. .

  That is, the transmission control unit 20 controls the drive current of the actuator 6 based on the current hydraulic characteristics of the actuator 6 that is held in advance, but from the hydraulic sensor 7 that detects the target pressure and the cylinder pressure due to variations in individual parts. If the actual hydraulic pressure is different from the above signal, the deviation is corrected by feedback control so that the actual cylinder pressure becomes the target pressure.

  At this time, if a failure in the hydraulic sensor 7, particularly a contact failure of the ground line of the hydraulic sensor 7 or the like, an intermediate potential fixing failure indicating a relatively high hydraulic pressure within the range assumed in the actual machine occurs, is indicated by the sensor voltage. The apparent hydraulic pressure is very high compared to the original target hydraulic pressure. Therefore, the transmission control unit 20 drives the actuator 6 to reduce the hydraulic pressure corresponding to the deviation by feedback control. However, the failure of the hydraulic sensor 7 is a fixing failure in which the output voltage is fixed to a constant value. Even if it is lowered, the apparent hydraulic pressure does not change.

  As a result, the transmission control unit 20 controls the actuator 6 up to the mechanical minimum hydraulic pressure, causing a phenomenon that the torque transmission capacity of the power transmission element falls below the required capacity, and the transmission slips. There is a risk of malfunction. Such a phenomenon occurs when the amount of change in the output voltage of the hydraulic sensor 7 is within a predetermined range and the deviation between the target hydraulic pressure and the apparent hydraulic pressure is greater than or equal to a predetermined value, the feedback control is prohibited and the state continues for a predetermined time. This can be avoided by providing a diagnostic function for determining failure and performing failure determination.

  However, in the normal case, the failure determination area is set narrower in consideration of erroneous determination, so in a transient situation such as immediately after startup, the above diagnostic function is effectively operated to detect an abnormality. It is difficult. A failure pattern having such a characteristic is likely to occur as a secondary failure during maintenance work such as replacement of a transmission. Therefore, the transmission control unit 20 performs such maintenance work when the maintenance work is executed. By changing the diagnosis condition to a condition that makes it easier to detect an abnormality than the normal diagnosis condition for a predetermined set time, it is possible to reliably detect failures that are difficult to detect in normal diagnosis under transient conditions I am doing so. For this reason, the transmission control unit 20 includes a maintenance operation detection unit 21, a diagnosis condition change unit 22, and a failure diagnosis unit 23 as diagnostic functions, as shown in FIG.

  The maintenance work detection unit 21 detects execution of maintenance work that may affect the operation of the device to be diagnosed. In the present embodiment, since the harnesses of the unit are removed during maintenance work such as when changing the transmission, maintenance is performed by checking whether the data in the backup RAM 20a of the transmission control unit 20 is destroyed. Detect work execution.

  Generally, an electronic control unit has a ROM that is a nonvolatile memory that mainly stores control programs, control constants, and the like, and a RAM that is a volatile memory that stores work data being calculated. A part of these memory spaces is used as a backup RAM area in which the memory is held by the backup power supply from the battery even after the vehicle ignition switch is turned off and the power supply to the unit is cut off to stop the operation. Part of learning data and diagnostic data is stored.

  Accordingly, the maintenance work detection unit 21 refers to the recorded contents of the backup RAM 20a when the ignition switch is turned on. When the recorded contents are not normal, the backup power supply is turned off while the ignition switch is turned off, that is, the transmission is turned off. It is considered that maintenance work including reprinting has been performed.

  In the backup RAM 20a, when the harness of the transmission control unit 20 is removed by transmission replacement or the like and the backup power is turned off, the stored contents are lost (stored data is destroyed). When the harness is connected due to the end of work or the like and the backup power is turned on again, the data in the backup RAM 20a becomes data that is completely unrelated to the original data (random data).

  Therefore, when the backup RAM 20a is cleared by initialization by turning on the ignition switch, the backup power supply is shut off by comparing with the initial value stored in the nonvolatile memory such as EEPROM in the control unit in advance. It is possible to determine whether or not the contents of are destroyed.

  The diagnosis condition changing unit 22 is detected by the maintenance operation detection unit 21 that a maintenance operation that may affect the operation of the device to be diagnosed is executed (in this embodiment, the data in the backup RAM 20a). If it is determined that the fault is not normal), the diagnostic condition is changed and set so that the abnormality is easily detected, for example, by widening the determination area of the fault diagnosis for a predetermined time from the normal time.

  In the case of diagnosis for an intermediate potential fixation abnormality of the hydraulic sensor 7 in the present embodiment, when it is detected that maintenance work such as transmission replacement has been performed, a diagnostic condition for the output voltage of the hydraulic sensor 7, for example, a sensor voltage value Is set to a specified voltage lower than normal and a change range wider than normal so as to make it easy to detect an abnormality. If no abnormality is detected after a predetermined time has elapsed after the change of the diagnosis condition, the normal diagnosis condition is restored, and the subsequent driving cycle is a normal diagnosis immediately after the ignition switch is turned on unless the data in the backup RAM 20a is destroyed. Perform fault diagnosis according to conditions.

  The failure diagnosis unit 23 performs failure diagnosis of the hydraulic sensor 7 under the diagnosis conditions set by the diagnosis condition change unit 22 and detects a sensor voltage abnormality. When an abnormality is detected, the hydraulic pressure feedback is stopped, the necessary pressure is secured, and the transmission slip is prevented.

  The above diagnostic function is not specific to the transmission system, and can be applied to the engine system in the same manner. Similar to the transmission control unit 20, the engine control unit 10 includes a backup RAM, and the backup RAM stores learning data and the like in fuel injection control and ignition timing control.

  Therefore, by checking whether the recorded contents of the backup RAM are normal or not, it is possible to determine whether or not the work such as engine replacement has been performed. Even if an abnormality has been induced, the abnormality can be detected at an early stage.

  In addition, the above failure diagnosis is not limited to sensor diagnosis, but can be applied in the same way to actuators, display devices such as meters and displays, and electronic devices such as ignition devices and actuator drive devices. Can do. For example, in a state where the response speed or driving force of the actuator is reduced due to deterioration over time or the like, work that may secondarily promote performance degradation of the actuators is performed, such as transmission replacement or engine replacement. In this case, it is possible to detect an abnormality at an early stage by diagnosing the actuators under conditions that make it easier to detect an abnormality than usual for a predetermined time, and to prevent a failure in the user's actual driving environment in advance. .

  Next, the program processing related to the above fault diagnosis will be described with reference to the flowchart of FIG.

  This failure diagnosis process is a process executed at a predetermined cycle after the ignition switch is turned from OFF to ON and the system is initialized. In the first step S1, it is checked whether or not the diagnostic condition change flag CT is set to 1. The diagnosis condition change flag CT is a flag indicating a change in the failure determination abnormality determination threshold (diagnosis condition). When CT = 1, the abnormality determination threshold is changed from the normal value.

  If CT = 0 in step S1 and the abnormality determination threshold value in the failure diagnosis is not changed from the normal value, the process proceeds from step S1 to step S2 to determine whether the data in the backup RAM is normal. Investigate. As a result, if the backup RAM is normal, the process proceeds from step S2 to step S3.

  In step S3, a normal abnormality determination threshold value is set, and in step S4, it is checked whether or not a normal determination is made as a result of diagnosis using the normal abnormality determination threshold value. Then, if the diagnosis result is normal determination, the process exits from this process, and thereafter, every time this process is executed, the backup RAM is checked. As long as the backup RAM is normal, the diagnosis using the normal abnormality determination threshold value is performed. I do.

  On the other hand, if the data in the backup RAM is not normal in step S2, the process branches from step S2 to step S5, and the abnormality determination threshold value when the backup RAM data is destroyed (when maintenance work is performed that affects the operation of the diagnosis target device). Is set to a threshold value that makes it easier to detect an abnormality than the normal determination threshold value. In step S6, the diagnosis condition change flag CT is set to 1. In step S7, it is checked whether or not the diagnosis is normal by the diagnosis using the abnormality determination threshold value changed so that the abnormality is easily detected.

  If the normal determination is made by the diagnosis in step S7, it is checked in step S8 whether the normal determination continues for a predetermined time. When normality determination continues for a predetermined time, the process proceeds from step S8 to step S9, the diagnostic condition change flag CT is cleared to 0, and the process proceeds to step S3 for setting the above-described normal abnormality determination threshold value.

  On the other hand, when an abnormality is detected in the diagnosis using the abnormality determination threshold value at the normal time in step S4 or the diagnosis using the abnormality determination threshold value that makes it easier to detect the abnormality than at the normal time in step S7, Proceeding to step S10, the process shifts to an abnormality process, a driver warning or fail control is executed to ensure safety, and abnormality diagnosis data is recorded.

  As described above, in the present embodiment, when a maintenance operation that may affect the operation of the in-vehicle device is performed, the diagnosis condition is set to be more abnormal than the normal diagnosis condition for a predetermined set time. Since the conditions are changed so that they are easy to detect, it is possible to quickly discover new and potential failure factors that occur during vehicle maintenance work, and to prevent failures in the actual driving environment of the user. It is possible to improve preventive safety by avoiding it in advance. Moreover, since the failure diagnosis is performed only for a predetermined time after the execution of the maintenance work is detected, there is no possibility of erroneous diagnosis in the practical running of the user.

3 Hydraulic automatic transmission 7 Hydraulic sensor 20 Transmission control unit 20a Backup RAM (volatile memory for holding data with backup power supply)
21 Maintenance work detection unit 22 Diagnosis condition change unit 23 Failure diagnosis unit

Claims (3)

In the in-vehicle device diagnostic device that monitors the operation of the in-vehicle device and detects an abnormality of the in-vehicle device by comparing with a predetermined diagnosis condition,
A maintenance operation detector that detects execution of maintenance operations that may affect the operation of the in-vehicle device;
A diagnostic condition changing unit configured to change the diagnostic condition to a condition in which an abnormality is more easily detected than a normal diagnostic condition during a predetermined set time when the execution of the maintenance work is detected. Diagnostic device for in-vehicle equipment.   The maintenance operation detection unit refers to the recorded content of a volatile memory that retains the data of the electronic control device by a backup power supply even after the electronic control device that controls the in-vehicle device is stopped due to power interruption, and the recorded content is The in-vehicle device diagnosis apparatus according to claim 1, wherein when it is not normal, it is detected that the maintenance work has been executed.   The in-vehicle device diagnosis apparatus according to claim 1, wherein the in-vehicle device is a device of a hydraulically driven automatic transmission.

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