JPH0441738Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a vehicle charging system monitoring device that can monitor not only generator failures but also temporary circuit failures in the charging system circuit.

(Prior art) A vehicle battery is charged by an alternator driven by the engine, and the voltage at its terminals is kept almost constant by a regulator. If the alternator stops generating electricity, a warning lamp lights up to warn of the abnormality. FIG. 5 shows an example of a charging device, where 1 is a battery, 2 enclosed by a chain line is an alternator including a regulator circuit, 3 is an electrical load, and 4 is a warning lamp.

The alternator 2 includes a power generating section including a stator coil 21, a field coil 22, and a full-wave rectifier 23, and a resistor 2 that divides the battery voltage.
4, 25, a Zener diode 26 that determines the charging stop value, and a thermistor 27 for temperature correction.
It is constituted by a regulator section consisting of transistors 28, 29, and 30 and diodes _D1 and _D2 for protection and backflow prevention.

Warning lamp 4 is connected in series with ignition switch 5 between the L terminal of alternator 2 and the positive terminal of battery 1, and the B and S terminals of alternator 2 are also connected to the positive terminal of battery 1. There is.

Now, when the ignition switch 5 is turned on when starting the engine, the field coil 22 is energized from the battery 1 via the L terminal, and the engine is started by the starter motor (not shown). As a result, the alternator rotor rotates and three-phase alternating current voltage is induced in the stator coil.
The three-phase AC voltage is rectified by a full-wave rectifier 23,
The battery 1 is charged via the B terminal, and power is also supplied to the field coil 22 via the point A.

In this way, the battery 1 is charged and its terminal voltage increases, and when the voltage at the midpoint C between the voltage dividing resistors 24 and 25 exceeds the breakdown voltage of the Zener diode 26, the transistor 28 becomes conductive and the voltage at point A decreases. , the power supply to the field coil 22 is cut off, the induced voltage becomes zero, and charging of the battery is stopped.

When the terminal voltage of battery 1 drops below a specified value, transistor 28 becomes non-conductive, transistors 29 and 30 become conductive, a current-carrying circuit is formed to field coil 22, an induced voltage is generated, and battery 1 is charged. starts.

By the way, if the current supply circuit to the field coil 22 is cut off due to disconnection or the like, the induced voltage becomes zero and the voltage at point A becomes zero, so the warning lamp 4
Battery voltage is applied to both ends of the generator, which lights up to warn of abnormalities in the generator.

However, even though the alternator's generator function is normal and the warning lamp 4 does not light up, the power generated by the alternator 2 may not be supplied to the battery 1 due to poor contact between the B and S terminals of the alternator 2. The terminal voltage of battery 1 may not be supplied to the regulator section of alternator 2, or the characteristics of the transistors and Zener diodes that make up the regulator section may change over time, or the resistance value of the lead wire connecting alternator 2 and battery 1 may occur. There is a problem that normal charging and voltage adjustment functions may not be performed due to the increase in voltage due to high temperature and the resulting voltage drop.

(Purpose and structure of the invention) The present invention was made in view of the above points, and its purpose is to monitor not only generator failures but also circuit failures in the charging system circuit. After converting the field coil voltage frequency into a corresponding voltage value, it is compared with the battery terminal voltage, and if the comparison result exceeds a predetermined value, it is determined that there is an abnormality in the charging system circuit.

(Example) The present invention will be explained below based on the drawings.

FIG. 1 shows an electric circuit of an embodiment of the charging system monitoring device according to the present invention, and this embodiment is the fifth embodiment of the charging system monitoring device according to the present invention.
This is the conventional charging device shown in the figure with a monitoring circuit and warning lamp added. That is, the monitoring circuit 6
is the frequency at which the frequency of the voltage supplied to the field coil 22 of the alternator 2 is converted into voltage -
A voltage (F/V) converter 61 and a voltage width centered around a predetermined judgment reference value V _B (for example, 13.5V) of the battery 1 (V _F1 to V _F2 shown in FIG. 3 described later)
and a comparison circuit 62 which compares the output V _F of the F/V converter 61 and outputs an "H" level when V _F is outside this voltage range.
The warning lamp 7 is connected to the positive terminal of the battery 1 via an operation limit switch 8, which will be described later, and is also grounded via a contact 9a of a relay 9. The coil 9b of the relay 9 is connected to the comparison circuit 62 of the monitoring circuit 6.
is connected to the output terminal of The operation limit switch 8 determines the state of the vehicle based on output signals from the engine rotation sensor 10a, the engine cooling water temperature sensor 10b, and the load operation detector 10c that detects whether the electrical load is in the operating state. When the condition matches a preset condition, the condition determiner 1
It is closed by the ON signal from 1. For example, if you want to monitor the charging system while it is idling, the condition is to set the engine speed to
The engine speed is 600 rpm, the engine water temperature is 80° C., and all electrical loads are set to no load. Only when these conditions are met, the condition determiner 11 outputs an ON signal, and this ON signal turns on the operation limit switch 8. The reason why this operation limit switch 8 is provided is that even with the same electrical load, the F/V converter 6
This is to prevent the warning lamp 7 from being erroneously turned on even though the charging system is not abnormal due to a change in the output of the charging system.

Next, the charging system abnormality monitoring operation in the embodiment shown in FIG. 1 will be explained using FIGS. 2 and 3. In the following description, it is assumed that the state of the vehicle matches the set conditions and the operation restriction switch 8 is turned on at the time of monitoring.

Now, when the alternator is operating normally and the battery is being charged, as shown in Figure 2A, the current generated by the power generation flows through the field coil 22, and the terminal voltage of the battery 1 reaches the predetermined criterion as shown in Figure 2B. When the voltage is slightly higher than the current value, when the electrical load is activated and the load current increases (see c in the same figure), the terminal voltage of the battery 1 decreases.

At this time, in the monitoring circuit 6, the frequency of the field coil supply voltage is converted into voltage by the F/V converter 61 as shown in FIG. In order to compensate for the drop in terminal voltage, the frequency of the voltage supplied to the field coil 22 is reduced by the function of the regulator section. As a result, if there is no abnormality in the charging system circuit, the generated power will gradually increase, the battery voltage will recover toward the judgment reference value as shown in Figure 2 (b), and the output of the F/V converter 61 will be A on D of the same figure
As shown in , it increases rapidly and eventually returns to the level before the load operation.

(1) However, if there is an abnormality in the battery voltage detection system due to, for example, a poor contact of the S terminal of the alternator 2 or changes in the characteristics and resistance values of the Zener diode 26 and transistors 28, 29, and 30 in the regulator section over time, the battery 1 If the terminal voltage cannot be detected normally, the frequency is abnormally low because the alternator 2 continues to send current to the field coil 22 in an attempt to increase the amount of power generation. As a result, the output of the F/V converter 61
V _F has a delayed rise as shown by B in Figure 2D,
Since the voltage falls below the voltage range (V _F1 to V _F2 ) indicated by diagonal lines, an "H" level abnormal signal is output from the comparison circuit 62 of the monitoring circuit 6, and the coil 9b of the relay 9
When the contact 9a is energized and the contact 9a is closed, the warning lamp 7 lights up to notify of an abnormality as shown in FIG. 2E. This abnormal region is shown as NG1 in FIG.

(2) Another possible abnormality is a poor contact between the terminals of the battery 2 or an increase in the resistance value within the regulator.

In this case, since the B and S terminals of the alternator 2 are originally connected, the generated voltage at the B terminal will be mistakenly detected as the battery terminal voltage, and it will be determined that sufficient charging has already occurred, and the field coil 22 will As a result, the generated voltage (this voltage is considered as the battery terminal voltage) becomes zero, so that the field coil 22 starts to be energized again, and the generated voltage appears at the B terminal. After that, power generation and stop are repeated at a fast cycle, so the output of the F/V converter 61 of the monitoring circuit 6 quickly recovers as shown by C in _FIG . _F2 )
The relay 9 is energized by the "H" level abnormality signal output from the comparator circuit 62, and the warning lamp 7 lights up (FIG. 2(e)) to notify the reference abnormality. This abnormal region is shown as NG2 in FIG.

FIG. 4 shows another embodiment of the monitoring device according to the invention. In this embodiment, a monitoring device according to the present invention is applied to a charging system configured to control power generation of an alternator according to operating conditions.

In the figure, components that are the same as those shown in FIG. A power generation controller 12 inputs various operating conditions such as engine cooling water temperature and outputs a voltage adjustment signal according to the driving pattern, and a power generation controller 12 that inputs various operating conditions such as engine cooling water temperature and outputs a voltage adjustment signal according to the driving pattern. An IC control circuit 13 for controlling on/off is provided. controller 1
2 also outputs a determination reference value for abnormality monitoring according to the driving pattern.

Next, only the monitoring operation of this embodiment will be explained.

In the monitoring circuit 6, the frequency of the voltage applied to the field coil 22 is converted into a corresponding voltage value by the F/V converter 61, and then in the comparison circuit 62,
The relay 9 is energized when the frequency of the field coil voltage deviates above or below this voltage range by comparing it with a certain voltage range centered on the judgment reference value according to the driving pattern output from the power generation controller 12. An abnormality signal is output, and the warning lamp 7 lights up to notify the circuit of an abnormality. The operation of the monitoring circuit 6 itself is exactly the same as the embodiment shown in FIG. 1, but it differs from the embodiment shown in FIG. 1 in that the judgment reference value changes depending on the driving pattern of the vehicle.

(Effects of the invention) As explained above, in this invention, after converting the field coil voltage frequency of the alternator into a corresponding voltage value, it is compared with the battery terminal voltage, and if the comparison result exceeds a predetermined value, charging is performed. Since the system is configured to determine that there is an abnormality in the system circuit, power generation will not be stopped due to deterioration in the performance of the voltage supply terminal of the regulator, battery voltage detection terminal, or battery circuit elements, or an abnormality in the charging circuit due to secular changes in resistance value. Circuit abnormalities can be monitored.

[Brief explanation of drawings]

Fig. 1 shows an electric circuit of one embodiment of the charging system monitoring device according to the present invention, Fig. 2 shows a signal waveform diagram of each part of the charging system monitoring device, and Fig. 3 shows the relationship between field coil voltage frequency and battery terminal voltage. 4 shows an electric circuit of another embodiment of the charging system monitoring device according to the present invention, and FIG. 5 shows an example of a conventional charging device with a monitoring function. 1...Battery, 2...Alternator, 3...
...Electrical load, 4...Warning lamp, 5...Ignition switch, 6...Monitoring circuit, 7...Warning lamp, 8...Operation limit switch, 9...Relay,
22... Field coil, 23... Full wave rectifier, 26... Zener diode, 61... F/
V converter, 62...comparison circuit.

Claims (1)

[Scope of utility model registration request] A monitoring device for a vehicle charging system that charges a battery by an alternator driven by an engine includes a frequency-voltage converter that converts the frequency of the field coil voltage of the alternator into voltage, and a terminal voltage detector that detects the terminal voltage of the battery. means, a comparison circuit that compares the voltage converted from the frequency of the field coil voltage and the battery terminal voltage and outputs an abnormal signal when the difference between the two voltages exceeds a predetermined value; and an abnormal signal from the comparison circuit. 1. A monitoring device for a vehicle charging system, comprising: warning means for warning of an abnormality in a charging circuit.