JPH10250501A - Self-diagnosing method and device for vehicular power generating circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the performing of diagnostic detection by mistake even when a power supply is momentarily disconnected. SOLUTION: When a main switch 11 is turned on, an ECU 19 self-holds an ECU power supply with a main relay 20 actuated. A level confirmation circuit 26 confirms that the L terminal of a regulator 14 becomes low in level within a first time set in advance has elapsed after an ignition switch 11 has been turned on, and a standby OK flag is set to represent '1' in a standby RAM 23. The CPU allows diagnostic detection to be performed when a standby flag represents '0' at the time when a second time set in advance has been measured after the ECU power supply is turned on. Even if the ECU power supply is momentarily disconnected if only the regulator flag is set to represent '1', when the ECU power supply rises after momentary disconnection has taken place, and even if the output of the regulator terminal does not become low in level, a diagnostic detection will never be actuated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a self-diagnosis method and apparatus for a vehicle power generation circuit for diagnosing, storing and displaying an abnormal location when an abnormality occurs in a power generation circuit of an automobile.

[0002]

2. Description of the Related Art Conventionally, for example, Japanese Unexamined Patent Application Publication No.
As disclosed in Japanese Patent Application Laid-Open No. H05-5, there is an automatic diagnosis in which data of each part of an electronically controlled vehicle is stored in a random access memory (hereinafter abbreviated as “RAM”) backed up by a battery and comprehensively analyzed. Is being done. The automatic diagnosis is performed, for example, when the ignition switch is turned on to start driving the vehicle or when an operation abnormality occurs. The self-diagnosis function is executed by an electronic control unit (hereinafter abbreviated as “ECU”) mounted on the vehicle. When the ignition switch is turned on, the ECU is supplied with power and becomes operable.However, when the ignition switch is turned off, the ECU stops operation even during the self-diagnosis, and when the data is analyzed later, There is a possibility that accurate diagnosis cannot be performed. In the prior art of Japanese Patent Laid-Open No. 6-74085, a flag indicating a state in which data is being stored in a non-volatile memory is used to determine whether or not data is completely stored at the time of diagnosis.
Try to prevent wrong diagnosis.

FIG. 6 shows a schematic configuration of a power generation circuit of an automobile. The ignition switch 1 is operated by a driver of the vehicle, and electric power required for operation of the vehicle is supplied by a battery 2 and an alternator 3 which is a combination of an AC generator and a rectifier. The alternator 3 is driven to rotate by the engine, and the output voltage fluctuates depending on the rotation speed. Therefore, the regulator 4 is used to control the output voltage within a certain range. When starting the engine, it is necessary to further turn the ignition switch 1 to rotate the starter 8 to start the engine. An ECU 9 is provided for controlling the engine and performing self-diagnosis of the power generation circuit.

FIG. 7 shows an operation performed by the ECU 9 shown in FIG. 6 when determining whether to start or stop the engine. At time t0, the ignition switch (hereinafter referred to as “IG SW”)
The power of the ECU 9 is also turned on. The regulator L terminal is at a low level from time t0 to time t1, and rises to a high level after time t1. The low level and the high level are distinguished according to the input logic level of the semiconductor integrated circuit mounted on the ECU 9. In the operation of the ECU, as part of the initial operation after turning on the power, the time t1
Up to two diagnostic check periods are provided, and when the regulator L terminal never goes low during this period, a diagnosis function, which is a self-diagnosis, is activated.

[0005]

In the determination of the operation or stop of the engine by the regulator L terminal as shown in FIG. 7, the ECU power supply is momentarily interrupted, for example, a momentary interruption from time t0 to time t10 to time t11. Occurs, the initial operation is started again, and a low level is detected at the regulator L terminal from time t10 to time t12 when the diagnosis check period ends. However, during this period, since the engine is rotating normally, the level of the regulator L terminal is high and never goes to low. Therefore, since the low level cannot be detected at all in the diagnosis check period, a diagnosis function, which is a self-diagnosis function, is started. When the diagnosis function is started, for example, an indication that the engine is stopped is displayed to the driver of the vehicle, or various controls are switched to the fail-safe side, so that the traveling speed of the vehicle is undesired for the driver. There is a possibility that the speed may be switched to a low speed. Further, there is a possibility that a normal component is erroneously recognized as a component requiring replacement.

The prior art of Japanese Patent Application Laid-Open No. 6-74085 aims at judging whether or not data storage is in progress after the ignition switch is shut off to prevent errors in self-diagnosis. It is not effective that there is a possibility that the judgment accompanying the conversion operation may be erroneous due to a momentary power interruption.

An object of the present invention is to provide a method and apparatus for self-diagnosis of a power generation circuit for a vehicle, which can appropriately determine whether to start or stop the engine even if there is a momentary power failure.

[0008]

SUMMARY OF THE INVENTION The present invention is a vehicle power generation circuit including a generator which is driven to rotate by an engine, and a regulator which keeps an output voltage from the generator within a predetermined range. Predetermined first
Within the time, it is checked whether or not the output voltage from the regulator is at a low level within a predetermined range, and the check result is stored, and after the power for operation is turned on, the predetermined time longer than the first time is determined. After the lapse of the second time, referring to the stored confirmation result, when the output level of the regulator is not low, a predetermined self-diagnosis is performed, and after the ignition switch is turned off, the confirmation result is low. A self-diagnosis method for a vehicle power generation circuit, characterized in that initialization is performed so as to indicate that there is no power generation circuit. According to the present invention, the first predetermined value after the ignition switch is turned on.
When it is confirmed that the regulator has a low level within a predetermined range within the time, it is determined that the power generation circuit is normal. The self-diagnosis is not performed even after a predetermined second time longer than the first time has elapsed after the input of the operating power. Since the confirmation result is initialized to indicate that the level has not become low after the ignition switch is turned off, unnecessary self-diagnosis can be avoided according to the result after the ignition switch is turned on.

Further, the present invention provides a power generation circuit for a vehicle, comprising: a generator supplied with operating power after the ignition switch is turned on and driven to rotate by an engine; and a regulator for maintaining an output voltage from the generator in a predetermined range. A self-diagnosis device, which measures time elapsed after turning on the operating power and checks whether the output voltage from the regulator is at a low level within a predetermined range after turning on the ignition switch. Level confirmation means to perform, and by the time the time counts the predetermined first time,
A non-volatile memory for storing the confirmation result of the level confirmation means, and when the predetermined second time longer than the first time is measured by the timer, the confirmation result stored in the non-volatile memory is read out from the regulator. When the output of the regulator is not low, self-diagnosis means for performing a predetermined self-diagnosis, and detection of the ignition switch being shut off, and confirming the result of the nonvolatile memory that the output from the regulator is not low. A self-diagnosis device for a vehicular power generation circuit, comprising: initialization means for initializing as shown. According to the present invention, the nonvolatile memory has a level indicating whether or not the output voltage from the regulator falls to a low level within a predetermined range before the first time predetermined by the timing means is measured after the supply of the operating power. The confirmation result by the confirmation means is stored. The self-diagnosis means
When the predetermined second time longer than the first time is measured by the timer, the confirmation result stored in the non-volatile memory is read out, and the predetermined result is determined when the output from the regulator is not at a low level. Perform self-diagnosis.
The initialization means detects that the ignition switch has been turned off, and when the ignition switch is turned off, initializes the confirmation result of the nonvolatile memory so as to indicate that the output from the regulator is not at a low level. Even if an instantaneous interruption or the like occurs, self-diagnosis is not performed at the time of startup, and undesired results due to erroneous operation of the self-diagnosis function can be prevented.

[0010]

FIG. 1 shows a schematic electrical configuration of a self-diagnosis apparatus according to an embodiment of the present invention. When the ignition switch 11 is turned on, the self-diagnosis device 10 determines whether or not the engine has started normally. To start the engine, it is necessary to turn the ignition switch 11 from the ignition position to the starter position. At the ignition position of the ignition switch 11, the battery 12 is connected to the output of the alternator 13 and the regulator 14, the alternator 13 generates power, and the regulator 14 charges the battery 12 with DC power limited to a certain range. At the starter position of the ignition switch 11, the electric power from the battery 12 is guided to the starter 18 to start the engine.

When the engine starts normally, the alternator 13 is driven to rotate, and a voltage capable of charging the battery 12 is generated from the regulator 14. Such a change in the output voltage of the regulator 14 is
Monitoring to determine whether the engine is operating normally. The ECU 19 includes the ignition switch 1
1 is turned on to the ignition position, power is supplied, and even if the ignition switch 11 is cut off from the ignition position by the main relay 20, a self-holding circuit is configured to supply power from the battery 12 for a certain period of time. Have been.

In the ECU 19, a central processing unit (hereinafter abbreviated as "CPU") 21, a read-only memory (hereinafter abbreviated as "ROM") 22, a standby RAM 23 backed up by a battery, a timer 24, and an initialization circuit 2
5 and a level confirmation circuit 26 are included. The level check circuit 26 detects the voltage of the terminal L of the regulator 14 and checks the output level.

FIG. 2 shows a self-diagnosis operation of the power supply circuit by the ECU 19 of FIG. The operation starts from step a1. In step a2, the ignition switch 11 is turned on. At step a3, the main relay 20 is turned on. In step a4, it is determined whether or not a level confirmation time as a first time has elapsed since the power was turned on. When it is determined that the elapsed time has not elapsed, it is determined whether the regulator L terminal is at a low level. When it is at the low level, the standby RAM 23 or the nonvolatile read-only memory E
² Set the regulator OK flag provided in the PROM or the like to 1. When step a6 is completed, or when it is determined in step a4 or step a4 that the level check time has elapsed since the power was turned on, or in step a4.
When it is determined in step 5 that the regulator L terminal is not at the low level, the process proceeds to step a7. In step a7, the second check timing of the regulator OK flag is set.
It is determined whether time has elapsed. In step a8, it is determined whether or not the regulator OK flag is 0. If it is detected in step a6 that the regulator OK flag has not been set to 1, the flow proceeds to step a9, in which a diagnosis as a self-diagnosis function is performed. When it is determined in step a7 that it is not the regulator OK flag check timing, when it is determined in step a8 that the regulator OK flag is not 0, that is, when it is 1, or when the process of step a9 is completed, the process proceeds to step a10. In step a10, the ignition switch is turned on
Is determined to have changed from OFF to OFF. When it is determined that it has not changed, the process returns to step a4. When it is determined in step a10 that the ignition switch has been turned off, the regulator OK flag is set to 0.
And the main relay 20 is turned off in step a12.
FF is set, and the process ends at step a13.

FIG. 3 shows the timing of the self-diagnosis according to the processing of FIG. When the ignition switch is turned on from time t20 and turned on, the regulator L terminal is at the low level during the time from time t22 to time t20, which is the first predetermined time, until time t21.
A regulator OK flag set at a specific address in the standby RAM 23 is set from 0 to 1. At time t23 when the second time has elapsed since the ignition switch was turned on, the flag stored in the standby RAM 23 is checked. In this case, since the regulator OK flag is set, no diagnostic detection operation is performed.

FIG. 4 shows the operation from step a10 to step a13 in FIG. At time t20, after the ignition switch 11 is turned on and the ECU power is also turned on,
When the ignition switch is turned off at time t24, the ECU power supply is turned off at time t25, which is delayed by several seconds. The main relay 20 shown in FIG. 1 holds the self-holding until the excitation of the relay coil is stopped even if the ignition switch 11 is cut off.
The CU power can be held. During this time, the standby RA
The storage contents of the regulator OK flag of M23 are reset to 0. In response to the turning off of the ignition switch 11, data for self-diagnosis is collected and the standby RAM 2
3 can also be stored.

FIG. 5 shows that the ignition switch 11 is
The difference between the present embodiment and the conventional concept when a momentary interruption occurs in the ECU power supply in the state of N will be described. When the ignition switch 11 is turned on from time t20 and a low level is detected at the regulator L terminal by time t21, the regulator OK flag rises to a high level when the low level is first detected. According to the conventional idea, at time t22, which is a fixed time after the ignition switch 11 is turned on.
By this time, if the level of the regulator L terminal is at the low level, the regulator OK flag is set to 1. However, if the ECU power supply is stopped for a short period of time from time t30 to time t31, the ignition switch 11 is kept turned on in this embodiment, and thus the reset of the regulator OK flag does not occur. Regulator O
Since the K flag is stored in the standby RAM 23, the stored contents are retained even when the ECU power supply is momentarily interrupted. On the other hand, if the regulator L terminal level is checked when the power supply of the ECU rises according to the conventional concept, the ECU is reset due to a momentary interruption, and the regulator L terminal level is checked again. In this case, since the level of the regulator L terminal remains at the high level, the self-diagnosis operation preset as the regulator diagnosis starts.

In this embodiment, the regulator OK flag is stored in the standby RAM 23 in which the stored contents are retained by backing up the power supply. However, the electrically rewritable nonvolatile read-only memory E ² PROM is used. The storage of the regulator OK flag can also be performed by using such a method.

[0018]

As described above, according to the present invention, when it is not detected that the regulator output voltage becomes low level within the first time after the ignition switch is turned on, the second time after the operation power supply is turned on. Since the self-diagnosis is performed in advance, it is possible to prevent an erroneous operation of the self-diagnosis function even if an instantaneous interruption of the power or the like occurs while the ignition switch is turned on.

Further according to the invention, the self-diagnosis means comprises:
After the non-volatile memory confirms that the output level of the regulator is not at a low level within the predetermined range by the level checking means, the second predetermined level after the power for operation is turned on.
Start self-diagnosis after a lapse of time. The initialization means initializes the non-volatile memory after the ignition switch is turned off, and turns on the ignition switch because the level confirmation means indicates that the output voltage of the regulator does not become low level. The operation of the self-diagnosis function is stopped only when the regulator level becomes low before the elapse of the first time later, thereby avoiding trouble caused by unnecessary activation of the self-diagnosis.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a schematic electrical configuration of an embodiment of the present invention.

FIG. 2 is a flowchart showing a process of an ECU 19 in FIG.

FIG. 3 is a time chart showing an operation of the self-diagnosis device of FIG. 1;

FIG. 4 is a time chart showing an operation of the self-diagnosis device of FIG. 1;

5 is a time chart showing a difference in operation between the self-diagnosis device of FIG. 1 and a conventional self-diagnosis device when a momentary interruption occurs in the ECU power supply.

FIG. 6 is a block diagram showing a simplified configuration of a general vehicle power generation circuit.

FIG. 7 is a time chart showing an operation of a conventional self-diagnosis device.

[Explanation of symbols]

 Reference Signs List 10 Self-diagnosis device 11 Ignition switch 12 Battery 13 Alternator 14 Regulator 19 ECU 20 Main relay 21 CPU 22 ROM 23 Standby RAM 24 Timer 25 Initialization circuit 26 Level check circuit

Claims (2)

[Claims] 1. A vehicular power generation circuit comprising: a generator rotatably driven by an engine; and a regulator for maintaining an output voltage from the generator within a predetermined range. Check whether the output voltage from the regulator is at a low level in a predetermined range, store the check result, and after turning on the operating power, a predetermined second time longer than the first time has elapsed. Later, referring to the stored confirmation result, when the output level of the regulator is not low, a predetermined self-diagnosis is performed, and after the ignition switch is turned off, it indicates that the confirmation result is not low. Self-diagnosis method for a vehicle power generation circuit. 2. A self-diagnosis of a vehicular power generation circuit including a generator supplied with operating power after being turned on by an ignition switch and rotationally driven by an engine, and a regulator for maintaining an output voltage from the generator in a predetermined range. A device, comprising: a time-measuring means for measuring an elapsed time after turning on the operating power; and a level check for checking whether or not the output voltage from the regulator is at a low level within a predetermined range after turning on the ignition switch. Means, a non-volatile memory for storing a result of confirmation by the level confirmation means before the first time is counted, and a second predetermined time longer than the first time by the time measuring means.
When the time is measured, the confirmation result stored in the non-volatile memory is read, and when the output from the regulator is not at a low level, self-diagnosis means for performing a predetermined self-diagnosis and detection of ignition switch shutoff An initialization means for initializing the result of checking the non-volatile memory to indicate that the output from the regulator is not at a low level.