JPH0879981A - Method for judging abnormality of ac generator for vehicle - Google Patents

Abstract

PURPOSE: To provide an accurate and simple diagnostic control system of a vehicle-mounted generator by monitoring the amount of compensation of a generation voltage command value and integrating the fault diagnosis of the vehicle-mounted generator into the diagnosis of a conventional internal engine. CONSTITUTION: In an engine control unit 9, a target voltage is varied by a target voltage varying means 22 based on an operation state detection means 20 and a load state detection means 21. A compensation value operation device 25 is provided to compare the varied target voltage with the voltage of battery and to perform the operation of the compensation value from both and to compensate a voltage command value. The compensation value is compared with a limit value by a failure judgment means 26 and it is judged that a vehicle- mounted generator failed when the value is exceeded. Further, a failure is externally displayed by a failure alarm means 27, an abnormality storage means 29, and an abnormality detail display means 30.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for determining an abnormal state of a generator mounted on a vehicle and related to battery charge control.

[0002]

2. Description of the Related Art Conventionally, the control of a vehicle alternator mounted on an automobile and driven to rotate by an internal combustion engine to generate electric power is performed by intermittently controlling a field current by a control device generally called an IC regulator. Has been done. The IC regulator detects a storage voltage of an on-vehicle battery to be charged, and supplies a field current to generate power when the detected storage voltage is equal to or lower than a predetermined value. The current was cut off and power generation was stopped.

According to Japanese Patent Laid-Open No. 60-16195, the power generation operation of the generator is adapted to the vehicle operating state in accordance with not only the state of charge of the on-vehicle battery but also the state of the engine and the state of the electric load. There is known a control device for an alternator for a vehicle, which controls a generator using a microcomputer for controlling the generator. The control device takes in operating parameters of the internal combustion engine including an air conditioner, a sensor for detecting turning on of a headlight, and the like to detect an operating state or an electric load state. Then, the generated voltage of the generator corresponding to the detected operating state or electric load state is switched to perform the charging control.

It is known that when the generated voltage becomes an abnormal value due to the failure of the generator, the battery life is shortened by overcharging and discharging the battery.

In the case of the charging system failure in the case of the above-mentioned charging system, the decrease of the field current and the decrease of the battery voltage are monitored by the IC regulator of the generator, and the operation is performed by the battery alarm lamp in the driver's seat. I was warning the car of something wrong.

Also in the engine control system,
The battery voltage is monitored, and in this case, the absolute value of the battery voltage is used to determine the abnormality. However, in this case, the alarm function notifying the abnormality determination of the charging system is not added.

[0007]

The present engine control system consists of an exhaust control device as a battery load and an operating state detection sensor, and an abnormality of the charging system controlling the battery voltage shortens the life of the battery. Not only that, there is a risk that performance such as exhaust emission, drivability, and fuel efficiency will be greatly affected, and fault diagnosis of the charging system must be performed accurately.

According to the above-mentioned conventional technique, the decrease amount of the field current or the decrease amount of the battery voltage is used to determine the failure of the charging system, and the IC regulator of the generator is used to determine the battery alarm lamp in the driver's seat. It only alerted the driver to the abnormality. That is, this is the abnormality determination of the charging system using the IC regulator alone, and the abnormality determination is the absolute value determination of the field current and the battery voltage. In this case, the abnormality determination is limited to the state where the power generation is completely stopped (or the power generation amount close thereto). (This also applies to the battery voltage abnormality determination method on the side of the engine control system described above.) Therefore, although it is possible to detect an abnormality in the charging system that causes an abnormality in engine operation, it affects exhaust emission. It was not possible to detect such a small drop in battery voltage.

Further, as a problem in this case, when the absolute value of the battery voltage fluctuates due to the influence of the operating conditions of the vehicle, the engine, and the electric load such as the air conditioner and the heater, the relation between the abnormality determination threshold value and the battery voltage becomes There is also the risk of a mismatch and a false determination or undetectable fall.

In the present invention, in order to prevent power performance and fuel consumption related to the above problems, the abnormality of the charging system is accurately determined, and the failure status is displayed on the failure alarm to the driver or service. To provide.

[0011]

In order to solve the above problems, a target of a generator is set in a regulator for adjusting a generated voltage of a generator driven by an engine according to an engine operating state and an electric load use state. In order to absorb the difference between this target voltage and the actual battery voltage by transmitting a control signal corresponding to the generated voltage, a correction value is added to the target voltage transmission signal, and the charging system control is temporarily approached to the optimum generated voltage. In this case, when the correction value exceeds the limit value, determine the abnormality of the charging system, output the determination result, and use the following steps that can also output the operating state and generated voltage state at that time. Achieved by

A step of obtaining a voltage difference between a power generation voltage of the generator and a target power generation voltage, a step of obtaining a correction value using the voltage difference, a step of adding a correction to the transmitted control signal using the correction value, a correction Comparing the value with the limit value to determine the abnormality of the charging system, the step of transmitting an abnormality determination result signal to the alarm device, the operating state at the time of abnormality determination,
A step of storing the generated voltage state and a step of outputting the stored state content to an external diagnostic device.

[0013]

In the abnormality judging method for the vehicle alternator according to the present invention, the target value of generated voltage is constantly compared with the actual generated voltage, and the correction value of the target generated voltage control signal calculated as a result is monitored. Therefore, the abnormality of the charging system can be accurately determined.

Further, the abnormality determination result of the charging system can be treated in the same manner as the self-diagnosis result of the engine control system, the diagnostic items relating to the engine control can be intensively confirmed, and when the engine control is abnormal, Accurate failure cause determination is possible.

Further, since the failure status of the charging control system (operating status, generated voltage status, etc.) can be stored,
The failure analysis of the failed component can be performed accurately, and the reliability of the component supply to the market can be improved.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A vehicle AC generator control system according to an embodiment of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a diagram showing an overall configuration of a vehicle AC generation control system according to the present invention. In this figure, an internal combustion engine 7 mounted on a vehicle includes an output shaft that outputs a rotational torque, that is, a crankshaft. A generator 16 is mechanically connected to the crankshaft via a pulley 40 and a belt 41, and the battery 16 is charged by the generator 16. At this time, in the engine control unit (hereinafter abbreviated as C / U) 9, the internal combustion engine 7
Taking in the engine speed, battery voltage, engine water temperature, vehicle speed, etc, which are parameters that represent the operating state of
A power generation voltage corresponding to the operating state of the internal combustion engine 7 is internally selected, and a target voltage corresponding to the operating state is set. further,
The C / U 9 converts into a voltage command value corresponding to the set target voltage, and outputs it to the generator 16. The generator 16 takes in the voltage command value output from the C / U 9, and the IC regulator 17 inside the generator 16 has a generated voltage corresponding to the voltage command value sent from the C / U 9,
Feedback control is performed while comparing the regulated voltage of the IC regulator 17 with the voltage of the battery 14 to generate electricity.

FIG. 2 shows an outline of this control system in the control system for a vehicle AC generator of the present invention. In this figure, the C / U 9 takes in engine speed, electric load, etc. from various sensors 15. Inside the C / U 9, the vehicle driving state and the vehicle load state are determined based on the detection by the driving state detecting means 20 and the electric load state detecting means 21 of the vehicle based on the parameters fetched from the various sensors 15. The target voltage varying means 22 varies the target voltage so that the generated voltage is optimum for the vehicle state according to the determined operating state and load state of the vehicle, and the target voltage is varied by the voltage commanding means 23. Convert to voltage command value.

Here, the voltage command value output from the C / U 9 has variations due to signal attenuation by the harness, variations in the generated voltage by the generator 16, etc., so that the generated voltage corresponds to the operating state. The varied target voltage does not match the battery power generation voltage 14 'and is not output to the generator 16 (IC regulator 17) according to the varied target voltage. The correction value calculation device 25 calculates a correction value for suppressing this variation.

In the correction value calculation device 25, when it is determined that the vehicle operating state or the vehicle load state is stable based on the input signals from the various sensors 15, the battery power generation detected by the voltage detecting means 24 is performed. The correction value is calculated by comparing the voltage 14 ′ and the target voltage varied according to the vehicle state by the target voltage varying means 22 and calculating the voltage difference between them or the voltage difference ratio by the correction value calculation device 25. Is calculated. The calculated correction value is stored for each storage area, and the correction value is corrected to the target voltage, and the voltage command value means 2
At 3, the command value is converted and output to the generator 16 (IC regulator 17).

The generator 16 compares the adjusted voltage adjusted by the IC regulator 17 inside the generator 16 with the voltage of the battery 14 to obtain a generated voltage corresponding to the voltage command value output from the C / U 9. Thus, the feedback control of the generated voltage is performed.

The above is the basic generator control system. Next, the abnormality determination of this charging system will be described below.

In FIG. 2, the abnormality determining means 26 determines whether the correction amount of the target voltage calculated by the correction value calculating device 25 is an abnormal value.

If the judgment result is normal, the command value of the correction value of the correction value computing device 25 is output as it is by the voltage command means 23 of the normal generator control.

When the judgment result is abnormal, the command value from the voltage command means is replaced with the above-mentioned limit value and the corresponding command value is outputted, and the abnormality warning means 27 transmits the system abnormality signal to the alarm device 28. To do.

On the other hand, a history of abnormality detection at the time of abnormality detection, a parameter indicating an abnormality such as an operating condition and an electric load state is stored in the abnormal state storage means 29, and the parameter is stored in the stored content display means 30. Information output of display device 3
Go to 1. Output to the display device 31 is possible even when there is a request from the display device.

FIG. 3 shows a flow of an embodiment relating to the limit value judgment method of the correction value.

First, this flow is started by a task of fixed time or another interrupt task (rotation interrupt, ignition interrupt, etc.).

When this task is started, control execution is judged (step 40) and control is executed (OK) or prohibited (N).
G) Make a determination. For example, this control is not executed when the engine is started or when the fuel is cut.

If it is permitted (OK), the process proceeds to the next step, operation state / electrical load state determination (step 41), and if it is prohibited (NG), the execution of this flow is ended.

Determination of operating state and electric load state (step 4
1) is a step of determining the current engine operating state and the state of the electric load. The operating state is based on various engine state parameter signals (for example, engine speed, engine water temperature, intake air amount, etc.) and the electric load. The state is determined from the electric load switch signal and the electric load state signal such as battery voltage. The target voltage of the generator is set in step 42 based on the state determination result.

Next, in step 44, it is determined whether the actual generated voltage value matches the target voltage. The actual voltage used for this determination is calculated in step 43, and the average voltage is calculated by the averaging process in order to eliminate the influence of the generated voltage fluctuation such as the ripple fluctuation of the generator.

The comparison between the target voltage and the actual voltage is performed in step 44, the difference or difference ratio (ratio of the differences) between them is calculated, and the correction value to be added to the target voltage is calculated in step 45. .

Next, at step 49, it is judged if the correction amount calculated at step 45 is a normal value. The determination method is to read the target voltage correction amount limit value preset in the memory from the state determination result of step 41 according to various operating states and load states (step 48),
It is compared with the correction value (step 49).

Regarding the reading of the limit value at this time, if the target voltage read for comparison and the limit value are not in the same operating condition range to be searched, there will be a problem (unmatch). (For example, if the state of the electric load is different, the target voltage and the required value of the limit value for the target voltage may be different, which may result in erroneous detection or undetectable.) Therefore, set when searching for the read value of both. The state range must be common.

If the correction value is within the range of the limit value in the comparison result of step 49, the correction value is added to the generated voltage target value (step of difference ratio) in step 46 for the normal generator control. In the case of step 47, the generated voltage command value is converted to the generator 16 (IC regulator 1
Output to 7).

When the correction value exceeds the range of the limit value in step 49, it is determined in step 50 that there is an abnormality, and the correction value is replaced with the limit value (step 51). Execute control.

The limit value set in step 48 may be either in the positive or negative direction (in the direction of increasing or decreasing the generated voltage) or in either direction.

In FIG. 4, the horizontal axis represents time, and the vertical axis represents voltage (or power generation command value), showing changes over time in correction of the target voltage. In this figure, the set values for both positive and negative directions are set to different values for the positive limit value and the negative limit value.
This is because the required values for the positive and negative sides differ depending on the performance of the battery and the emission requirements from the engine.
Although there is a difference depending on the vehicle concept, the battery depletion rather than overcharging causes more deterioration in drivability due to malfunction of the engine control device and damage to the vehicle such as stalls. It is better to raise (sensitivity to detect the drop of the actual voltage).

Finally, the operation (display control) after abnormality detection will be described with reference to FIG.

The flow of FIG. 5 is located after step 50 during activation of the fixed time task for abnormality determination or other interrupt tasks (rotation interrupt, ignition interrupt, etc.) in FIG.

First, when the abnormality determination is established in step 50 of FIG. 3, the process proceeds to step 61 and the abnormality determination result is recorded. In this method, generally, the abnormality determination flag (bit position of the specific RAM), which is assigned in advance, of the microcomputer or the backup RAM attached to the microcomputer is set to "1".
It is remembered by standing. Further, this determination result is stored together with other abnormality determination results of the self-diagnosis determination results (various sensors, actuators, etc.), and these determination results are stored in the order of the diagnostic history.

After recording the abnormality determination result of the generator in step 61, the process proceeds to step 62, in which the operating state of the vehicle or engine (engine speed, load, vehicle speed, etc.) at the time of abnormality determination,
Power generation status (battery voltage, electrical load switch status, etc.)
Memorize. This will be described later, but it will be the back data of the condition in which the abnormality determination was performed, and it will be useful for the analysis at the service dealer and the feedback to the generator design.

In step 63, the determination result of step 50 is displayed on the display device in real time, and it may be positioned before the step 61. Note that the failure of the generator is an important failure mode that makes the vehicle and engine unstartable, and this step should always be added in order to warn the abnormal driver.

From step 64, a display method relating to a communication with an external diagnostic device or a storage state output request such as a diagnostic result by the external diagnostic switch, an abnormal state, or the like.

First, step 64 is a step of determining whether or not a request signal from an external diagnostic device or an external diagnostic switch has been input. At the time of signal input (Yes), the stored data stored in steps 61 and 62 are transferred to an external diagnostic device (transfer of the stored data via a communication line) or another diagnostic device (for example, an output pattern to a display lamp or a buzzer). ).

When no display (No) is made in step 64, the steps after the storage data output in step 65 are skipped,
Go to the next Step 51 (or END).

Step 66 is a step of judging whether or not to erase the stored data. This is also determined by the presence / absence of a request signal from an external diagnostic device or the like as in step 64. When the erase request signal is input (Yes), the stored data is erased in step 67. When no signal is input (No), the stored data erasing process of step 67 is skipped, and the process proceeds to the next step 51 (or END).

Incidentally, in the flow of FIG. 5, step 64
˜67 (control block 70) may be executed by another task regardless of the control execution task of this flow.

As described above, according to the present invention, it is possible to accurately execute the failure (abnormality) determination of the charging system including the generator.

[0051]

In the abnormality judging method for the vehicle alternator according to the present invention, the target value of generated voltage is constantly compared with the actual generated voltage, and the correction value of the target generated voltage control signal calculated as a result is monitored. As a result, it is possible to accurately determine the abnormality of the charging system corresponding to various engine operating states and various charging states.

Further, since the abnormality determination result of the charging system can be treated in the same manner as the self-diagnosis result of the engine control system, the diagnostic control and the diagnostic function can be integrated.
It enables centralized management of diagnostic results and simplification of diagnostic system configuration.

Furthermore, since the failure status (operating status, power generation voltage status, etc.) of the charging control system can be stored,
It is possible to obtain back data of the failure analysis of the failed component, and this feedback improves the reliability of the component supply to the market.

[Brief description of drawings]

FIG. 1 is a control system configuration diagram of a vehicle AC generator according to the present invention.

FIG. 2 is a schematic diagram of a control system for a vehicle AC generator according to the present invention.

FIG. 3 is a flow chart of abnormality determination control of a vehicle generator.

FIG. 4 is a diagram illustrating an example of setting an abnormality determination limit value.

FIG. 5 is a data processing flowchart after abnormality determination.

[Explanation of symbols]

7 ... Internal combustion engine (engine), 9 ... Engine control unit (C / U), 14 ... Battery, 16 ... Generator,
17 ... IC regulator, 20 ... Operating state detecting means, 2
1 ... Load state detecting means, 22 ... Target voltage varying means, 23
... voltage commanding means, 24 ... voltage detecting means, 25 ... correction value computing device, 26 ... abnormality determining means, 27 ... abnormality warning means, 2
9 ... Abnormal state storage means, 30 ... Storage content display means.

Claims (6)

[Claims] 1. A target generator voltage control signal for the generator, which is set according to an operating state or an electric load use state, is set in a regulator for adjusting a generator voltage of a generator driven by an engine, and the generator is set. In the vehicle generator control method for updating the target power generation voltage control signal while correcting the control signal so that the voltage difference between the power generation voltage and the target power generation voltage becomes a predetermined value or less, the control signal A limit value of the correction amount is set in the correction adding means, and the abnormality determination of the vehicle alternator is performed by comparing the correction amount and the limit value to determine the abnormality of the control system of the vehicle generator. Method. 2. The abnormality of the vehicle alternator according to claim 1, further comprising abnormality display output means for displaying an abnormality or outputting an abnormality display to an external alarm device when the abnormality of the vehicle generator is judged. Judgment method. 3. An abnormal time information storage means for storing abnormal time information such as a vehicle operating condition parameter at the time of abnormality judgment and a history of abnormality detection at the time of abnormality judgment of the vehicle generator. A method for determining an abnormality of a vehicle generator, which is characterized in that 4. The vehicle generator according to claim 3, further comprising: storage information output means for outputting the storage information based on an external trigger signal to output abnormal time information in the abnormal state. Abnormality judgment method. 5. The abnormality judging method for a vehicle alternator according to claim 1, wherein the limit values are set on both positive and negative sides and the two values are not the same value. 6. The limit value is preset for each of the operating condition and the electric load condition, and the range of each setting condition is common to the setting condition range of the target voltage. A method for determining an abnormality of the vehicle alternator described.