JP4025398B2 - On-vehicle control device and fault diagnosis method used therefor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an in-vehicle control device having a fault diagnosis function for an external circuit including a signal line, and more particularly to an in-vehicle control device for connecting signal line groups of an external circuit through a connector.
[0002]
[Prior art]
2. Description of the Related Art Some in-vehicle control devices that are mounted on a vehicle and electrically control an engine or the like include a fault diagnosis function for an external circuit group including wiring (for example, an injector, a rotation speed detection sensor, and the like). This fault diagnosis function monitors a signal passed between the in-vehicle control device and each external circuit. For example, when a disconnection of the circuit is detected, a fault code indicating the fault of the circuit is stored. Perform processing such as displaying.
[0003]
Generally, the wiring of the external circuit group forms a harness that is bundled and accommodated in a common connector. And the external circuit group and the internal circuit of a vehicle-mounted control apparatus are electrically connected by connecting the harness and the connector provided in the vehicle-mounted control apparatus main body.
[0004]
[Problems to be solved by the invention]
In a conventional in-vehicle control device including a connector for connecting a harness of an external circuit, when the connector is not normally connected, the fault diagnosis function detects disconnection of the external circuit connected to the connector, and the external circuit An operation for storing and displaying a fault code indicating disconnection is performed. Thus, conventionally, even when the connector is simply connected poorly, the external circuit is mistakenly recognized as defective, and unnecessary work such as inspection and replacement of parts may be performed.
[0005]
Therefore, the present invention prevents inconvenience that a failure caused by a connection failure of a connector is a failure of an external circuit itself including wiring, and can avoid unnecessary inspection work and parts replacement. An object is to provide a control device.
[0006]
[Means for Solving the Problems]
In order to solve the above-described problems, the present invention provides a vehicle-mounted control device that is connected via a plurality of signal lines and that exchanges signals with a plurality of external circuits including sensors.
At least one connector connected to a harness that accommodates a plurality of signal lines from the plurality of external circuits in common;
For each external circuit including a signal line connected to the connector, whether or not it is normal, short-circuited or disconnected from the input and output is individually detected, and the number of external circuits detected as disconnected is determined in advance. When the number is greater than or equal to the number, it is determined that the connector is in a poor connection state, and diagnostic means for determining a sensor failure based on whether the output value from the sensor is greater than or equal to a predetermined value;
Output means for outputting information including a determination result of the diagnostic means;
It is provided with the vehicle-mounted control apparatus characterized by the above-mentioned.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0008]
FIG. 1 is a diagram showing an overall configuration of an engine control system to which an in-vehicle control device of the present invention is applied. In the figure, 1 is an in-vehicle control device for controlling the engine, 2 is a connector A connected to an external circuit on the engine side, and 3 is a connector B connected to an external circuit on the vehicle body side.
[0009]
Connected to the connector A2 of the in-vehicle controller 1 is a harness that accommodates signal lines such as an injector 8, an ISC valve (drive motor) 9, a water temperature sensor 12, a throttle opening sensor 13, and the like.
[0010]
The connector B3 includes a λ sensor 22 for detecting the oxygen concentration in the exhaust gas, an engine check lamp 25 for displaying the occurrence of a failure, each signal line of the diagnostic tool 19, and a harness that houses the power supply line 5, etc. Is connected. The diagnostic tool 19 is connected to check the type and position of the failure that has occurred during inspection and repair.
[0011]
FIG. 2 shows an electrical configuration of the engine control system.
[0012]
As shown in the figure, the actuators such as the injector 8 and the ISC valve 9 are connected to the battery 6 via the main relay 10 when the ignition switch 4 is turned on, and are driven by the on / off switching on the ground side by the in-vehicle control device 1. Controlled. The throttle opening sensor 13 has a partial pressure volume linked to the throttle, and divides the reference voltage (Vcc) supplied by the line 14. The relay 24 is for driving a solenoid 23 for an air conditioner. The power supply line 5 is connected to the battery 6 when the ignition switch 4 is turned on. The memory backup line 13 is always connected to the battery 6.
[0013]
As shown in FIG. 2, the in-vehicle controller 1 includes an actuator drive circuit 11 having a fault diagnosis function, a ROM 15, a RAM 16, a CPU 17, an input / output circuit 18 having an A / D converter, a communication serial interface 20, and a power supply circuit. 21 or the like.
[0014]
The ROM 15 stores a control program and control parameters in advance. A part of the plurality of memories forming the RAM 16 is a backup RAM that is constantly supplied with power from the line 13.
[0015]
The CPU 17 executes a control program stored in the ROM 15, processes input data from various sensors using control parameters, and outputs control data giving control contents of various actuators.
[0016]
The drive circuit 11 drives various actuators according to control data output from the CPU 17. In parallel with this, the voltage level in each signal line is output to the CPU 17 as detection information.
[0017]
The control program executed by the CPU 17 includes a fault diagnosis program group. The CPU 17 executes the program group to process the detection information from the actuator drive circuit 11, determine the position and type of the fault that has occurred, store the fault code to hold the content of the fault, engine check Notification of failure caused by lamps.
[0018]
Specifically, if it is determined that all the external circuits connected to the connector A2 have a disconnection fault, a fault code indicating that the connector A2 is not connected is stored in the backup RAM 16, and the engine check lamp 25 is turned on. Let In other cases, when there is a fault in the external circuit, the faulty circuit indicating the faulty circuit and the content of the fault is stored in the backup RAM 16 and the engine check lamp 25 is turned on.
[0019]
In addition, the structure of the control apparatus 1 is not limited to the above-mentioned thing. For example, a larger part of the functions of the control device 1 may be realized by a hardware circuit other than the CPU 17.
[0020]
The diagnostic tool 19 includes a CPU, a ROM, a RAM, an input / output interface, and a display unit (not shown), and is connected to the in-vehicle control device 1 at the time of inspection / repair. When connected to the control device 1, the diagnostic tool 19 receives the defect code stored in the backup RAM 16 from the communication interface 20, decodes it, and displays it on the display unit.
[0021]
The driver and the repair person can know from the lighting of the engine check lamp 25 that a failure has occurred in the external circuit. The details of the failure can be examined using the diagnostic tool 19. When the failure is due to the disconnection of the connector A2, the fact is displayed on the diagnostic tool 19. If the failure is in some external circuits, it is displayed what kind of failure occurs in which external circuit.
[0022]
When the failure is due to the disconnection of the connector A2, the repairer reconnects the connector A2 from the display of the diagnostic tool 19, performs power-on or reset operation on the in-vehicle control device 1, and performs circuit diagnosis operation. restart. Since the engine check lamp is turned off, it can be known that the failure has been resolved. As described above, when the failure is caused by the connection failure of the connector A2, the repairer does not need to perform unnecessary repair such as inspection or replacement of the external circuit.
[0023]
Next, a method for detecting and diagnosing a failure in the in-vehicle control device 1 will be described in more detail.
[0024]
In FIG. 3, the structural example of the actuator drive circuit 11 in the vehicle-mounted control apparatus 1 is shown. The drive circuit 11 includes a transistor 31, an input terminal I, a detection terminal D, and output terminals T1 and T2 for each control target. In the figure, only a portion corresponding to one of the injectors 8 is shown as an example. Here, the load of the injector 8 has a certain resistance component.
[0025]
The drive circuit 11 is supplied with a voltage corresponding to control data output from the CPU to the input terminal I, and switches the conduction state between the output terminals T1 and T2 by the transistor 31. When the transistor 31 is OFF, the output terminals T1 and T2 are in a non-conductive state, and the voltage at the detection terminal D (detection voltage V _D ) is V _HIGH that is substantially equal to the power supply voltage connected to the actuator. When the transistor 31 is ON, the output terminals T1 and T2 are in a conductive state, and the detection voltage V _D is V _LOW which is approximately 0V. At this time, the reason why the detection voltage V _D does not become 0 V is that a voltage drop occurs due to the ON resistance of the transistor 31 or the like that is very small compared to the resistance of the load 8. This detection voltage V _D is passed to the CPU 17 as detection data.
[0026]
The CPU 17 executes a fault diagnosis program, performs an output diagnosis operation for diagnosing the output-side external circuit, an input diagnosis operation for diagnosing the input-side external circuit, analyzes these diagnosis results, and analyzes the connector A circuit diagnosis operation for determining the connection state is performed. Note that these operations are preferably performed during a certain period of time at the start of engine startup when the operation of the external circuit becomes unstable.
[0027]
In the output diagnosis operation, the detection voltage V _D of the drive circuit 11 is checked, and processing for detecting a failure in an external circuit including wiring is performed. The failure mentioned here includes disconnection (open) of the coil 8 and the wirings 32 and 36 and short-circuiting (short-circuiting) of the coil 8 and the wiring 36 to the power supply voltage.
[0028]
FIG. 4 shows a flowchart of the output diagnosis operation. This operation is performed at regular intervals (for example, every 2 ms). Based on the data of the detection voltage V _D , the CPU 17 detects a short circuit when the transistor 31 is ON (step 101, YES), and detects an open state when the transistor 31 is OFF (step 101, NO). In short circuit detection, the detection voltages V _D and V _LOW are compared (step 102). If the detection voltage V _D is greater than V _LOW , it is determined that a short circuit has occurred, A defect flag is set (step 103). Here, V _LOW is, for example, a maximum value of V _D at the time of ON driving when the wiring is normal or a value slightly larger than the maximum value. On the other hand, in the detection of open, the detection voltages V _D and V _HIGH are compared (step 104). If the detection voltage V _D is smaller than V _HIGH , it is determined that a disconnection has occurred and the diagnosis target is determined. An open defect flag is set (step 105). Here, V _HIGH is, for example, a minimum value of V _D at the time of OFF driving when the wiring is normal or a value slightly smaller than the minimum value. If the detection voltage V _D is V _LOW or lower in step 102 or the detection voltage V _D is V _HIGH or higher in step 104, the fault flag to be diagnosed is cleared (step 107).
[0029]
Note that the diagnosis processing in steps 101, 102, and 103 may be realized by a hardware circuit, and the diagnosis result (short or open) may be passed to the CPU 17 to set a defect flag. When a short circuit is detected, the transistor 31 may be forcibly turned off in order to avoid damage to the transistor 31 and burnout of the harness due to overcurrent.
[0030]
FIG. 5 shows a flow of disconnection diagnosis processing of the throttle opening sensor 13 as an example of the input diagnosis operation. This operation is performed every predetermined time (for example, every 10 ms) or whenever A / D conversion of the throttle sensor 13 output is performed. First, the CPU 17 stores the A / D conversion value of the output of the throttle opening sensor 13 in a variable VISC on the RAM (step 201). Then, it is determined whether the value of the variable VISC is equal to or smaller than the predetermined value VISCLOW (step 202). If the value is equal to or smaller than the predetermined value, it is determined that a disconnection or a short circuit to the ground potential (grounding short) has occurred. An open failure flag for the throttle opening sensor 13 is set (step 204). If it is not determined in step 202 that a failure has occurred, it is determined whether VISC is equal to or greater than a predetermined value VISCHIGH (step 203). As a failure, a trouble flag for the high voltage side of the throttle opening sensor 13 is set (step 205). If it is determined in steps 202 and 203 that the VISC is within the normal range, the trouble flag of the throttle sensor is cleared (step 206). The water temperature sensor 12 can also detect a failure by examining its output voltage.
[0031]
FIG. 6 shows a process flow of the circuit diagnosis operation. This operation is also executed at regular time intervals (for example, every 10 ms). For the sake of simplification, the figure shows an example in which there is only one target for input diagnosis and output diagnosis. However, in actuality, connection to the connector A2 is performed by processing added to the step groups 310 and 311. Processing corresponding to all external circuits to be performed is performed. The CPU 17 first checks whether or not an open defect flag is set in each diagnosis (steps 301, 302, 303, etc.). If the open failure flag is set in all diagnoses, it is determined that the connector is in a disconnected state, a failure code indicating that the connector is not connected is stored in the backup RAM (step 304), and the engine check lamp is turned on. Turn on (step 307). If the condition in step 304 is not satisfied, but there is a fault flag that is set, it is determined that a fault has occurred in the external circuit, and the fault code corresponding to the fault flag that has been set is stored in the backup RAM. (Step 305), the engine check lamp is turned on (Step 307). The fault code stored at this time represents the location and type of the fault. If the failure flag is not set in all diagnoses, it is determined that there is no failure and the process is terminated.
[0032]
In order to prevent misdiagnosis, even when the open defect flag is set in all diagnoses, the process transition to step 304 is continuously performed without executing step 304 immediately. The execution of step 304 may be performed at the time of several times (multiple times).
[0033]
By the way, the connection state of the connector A2 includes an incomplete connection state in which a connection portion and a non-connection portion are mixed, in addition to a complete connection / non-connection state. In the case of an incomplete connection state, there may be a case where a disconnection failure flag is set and an unset one is mixed in the diagnosis of the external circuit. In this case, since the diagnosis processing of FIG. 6 does not diagnose that the connector is not connected, there is a possibility that unnecessary inspection / repair may be performed. In order to solve this problem, the diagnostic operation shown in FIG. 7 may be performed instead of the diagnostic operation of FIG.
[0034]
The diagnosis operation of FIG. 7 determines that the connector is disconnected when the number of open trouble flags set is greater than a predetermined number (NOPNFLG: a number less than the number of terminals of the connector A2). Specifically, the total number of open defect flags that are set is calculated and compared with the NOPNFLG (step 501). If the total number of open failure flags is greater than NOPNFLG, it is determined that the connector A2 has a connection failure, and a failure code indicating a connector connection failure is stored in the backup RAM (step 502). If the total number of open failure flags is equal to or less than NOPNFLG, it is determined whether the total number of failure flags is 0 (step 503). If not, all failure codes corresponding to the set failure flags are stored. (Step 504).
[0035]
All fault codes stored in the backup RAM are transmitted to the diagnostic tool 19 via the communication interface 20 when the diagnostic tool 19 is connected.
[0036]
Next, a second embodiment of the present invention will be described.
[0037]
In the present embodiment, the in-vehicle control device is configured not to diagnose the connection failure of the connector A2, but to store only the defect code for each external circuit as diagnosis information. The diagnosis of the connection failure of the connector A2 is performed by the diagnostic tool 19 based on the received fault code. Since other functions are the same as those in the first embodiment, description thereof is omitted here.
[0038]
FIG. 8 shows a processing flow of diagnostic processing performed by the diagnostic tool 19. The processing flow of FIG. 8 is executed by the CPU in the diagnostic tool 19. In addition, the figure shows an example in which there is one input diagnosis and one output diagnosis for simplification as in FIG.
[0039]
First, when the CPU of the diagnostic tool 19 is connected to the control device, it starts communication (step 400), and reads all fault codes stored in the backup RAM of the control device 1 (step 401). If the read fault code indicates that all external circuits connected to the connector A2 are open, it is determined that the connector A2 is in a disconnected state, and a display indicating that the connector is not connected is displayed (step 405). If a fault code exists but the condition in step 405 is not satisfied, it is determined that a fault has occurred in the external circuit, and a display indicating the fault occurrence position and type corresponding to each fault code is performed (step 406). 407). If there is no fault code, it is determined that there is no failure and the process is terminated.
[0040]
In this embodiment, the diagnostic function of the connector is provided to the diagnostic tool 19 so that the connector connection state is diagnosed and the diagnosis result is presented to the repair person without increasing the processing amount of the control device having a heavy processing load. be able to.
[0041]
Incidentally, in the embodiment described above, the control device 1 displays the diagnosis result on the external engine check lamp 25. However, as shown in FIG. 9, in the vicinity of the connectors A2 and B3 of the control device main body. The control device 1 may be configured to provide the display units 36 and 37 and present the diagnosis result by changing the display mode of the display units 36 and 37. For example, when an indicator lamp is used as each of the display units 36 and 37 and a connector connection failure is determined, the indicator lamp in the vicinity of the connector is blinked to detect an external circuit fault and determine that the connector connection is normal. In such a case, the indicator lamp in the vicinity of the connector connected to the external circuit is turned on. As a result, the repair worker can easily grasp the type and position of the failure, and can quickly perform repair work such as connection confirmation and improvement. The display unit is not limited to an indicator lamp. For example, a liquid crystal display that displays a code may be used to designate a faulty external circuit.
Furthermore, the control device 1 according to the above embodiment includes two connectors for connecting to an external circuit. However, even when three or more connectors are provided, the above determination processing is performed on each connector. By carrying out correspondingly, the same operation and effect can be easily realized. Of course, as shown in FIG. 10, the same diagnostic operation can be realized even in a configuration in which the detachable connector 39 and the harness 38 directly connected to the internal circuit are mixed.
[0042]
The control device 1 according to the above embodiment turns on the engine check lamp when there is a failure. However, if it is determined that the connector A2 is not connected, the engine check lamp is turned on and off. You may make it do. In this case, the repair person can know that the connector A2 is not connected without using a diagnostic tool. Furthermore, instead of the engine check lamp, an alarm circuit such as a speech synthesizer or a display device may be provided to indicate the type and location of the failure by voice or display.
[0043]
【The invention's effect】
As described above, according to the present invention, it is possible to prevent a failure caused by a poor connection of the connector from being mistaken as a failure of the external circuit itself, and to avoid unnecessary inspection work and parts replacement. An in-vehicle control device can be provided.
[Brief description of the drawings]
FIG. 1 is a diagram showing an overall configuration of an engine control system to which a control device according to an embodiment of the present invention is applied.
FIG. 2 is a diagram showing an electrical configuration of the system shown in FIG.
FIG. 3 is a diagram illustrating a configuration of a drive circuit in a control device.
FIG. 4 is a diagram illustrating an output diagnosis operation of a control device.
FIG. 5 is a diagram illustrating an input diagnosis operation of a control device.
FIG. 6 is a diagram illustrating a circuit diagnosis operation of the control device.
FIG. 7 is a diagram illustrating another example of a circuit diagnosis operation.
FIG. 8 is a diagram showing a circuit diagnostic operation of a diagnostic tool according to another embodiment of the present invention.
FIG. 9 is a diagram illustrating an example of an appearance of a control device.
FIG. 10 is a diagram showing another example of the appearance of the control device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Vehicle-mounted control apparatus, 2 ... Connector A, 3 ... Connector B, 11 ... Drive circuit, 15 ... ROM, 16 ... RAM, 17 ... CPU, 18 ... Input / output circuit 18, 20 ... Serial interface for communication, 21 ... Power supply circuit, 19 ... diagnostic tool.

Claims (6)

In a vehicle-mounted control device that is connected via a plurality of signal lines and that exchanges signals with a plurality of external circuits including sensors ,
At least one connector connected to a harness that accommodates a plurality of signal lines from the plurality of external circuits in common;
For each external circuit including a signal line connected to the connector, whether or not it is normal, short-circuited or disconnected from the input and output is individually detected, and the number of external circuits detected as disconnected is determined in advance. When the number is greater than or equal to the number, it is determined that the connector is in a poor connection state, and diagnostic means for determining a sensor failure based on whether the output value from the sensor is greater than or equal to a predetermined value ;
An in-vehicle control device comprising: output means for outputting information including a determination result of the diagnosis means. The in-vehicle control device according to claim 1,
The in-vehicle control device characterized in that the output information of the output means includes individual detection results for each external circuit. The in-vehicle control device according to claim 2,
The on-vehicle control device characterized in that the output means outputs the detection result information only for an external circuit connected to a connector whose connection state is determined to be normal.   2. The in-vehicle control apparatus according to claim 1, wherein the in-vehicle control apparatus is connected to an external alarm unit, and the alarm unit presents a determination result of the diagnosis unit based on output information of the output unit.   The in-vehicle control device according to claim 1, further comprising a display unit arranged in the vicinity of the connector, and according to a determination result for each connector of the diagnostic unit according to the output information of the output unit, a display of the vicinity of the connector The vehicle-mounted control apparatus characterized by the display mode of a part being changed. A fault diagnosis method used in a vehicle-mounted control device that is connected via a plurality of signal lines and exchanges signals with a plurality of external circuits including sensors ,
The in-vehicle control device is
Having at least one connector connected to a harness commonly housing a plurality of signal lines from the plurality of external circuits;
For each external circuit including a signal line connected to the connector, whether or not it is normal, short-circuited or disconnected from the input and output is individually detected, and the number of external circuits detected as disconnected is determined in advance. If the number is greater than or equal to the number, it is determined that the connector is in a poor connection state, and information including a determination result for determining a failure of the sensor depending on whether the output value from the sensor is equal to or greater than a predetermined value is output. A characteristic fault diagnosis method.

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