JPS642013B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a diagnostic device for an automotive alternator, and particularly to a diagnostic device for an alternating current generator for use in an automobile, and particularly for detecting disconnection between a main rectifier and an auxiliary rectifier of an alternator having an auxiliary rectifier for supplying direct current to an excitation winding. The present invention relates to a fault diagnosis device suitable for detecting.

As is known from Japanese Unexamined Patent Publication No. 55-99041, this type of conventional fault diagnosis device detects the average value of the output voltage of the auxiliary rectifier, the number of ripples of the output terminal voltage of the main rectifier, the ripple width, and the average value of the voltage. Abnormalities in each part are diagnosed based on the conditions.

However, this conventional example has a problem in that it is not possible to accurately detect a disconnection between the main rectifier and the auxiliary rectifier.

In other words, in consideration of the change in output voltage due to the temperature of the storage battery, the voltage regulator's adjusted voltage is adjusted to a maximum of 15V at -30℃ and a minimum of 13V at 115℃ when its standard setting value is 14.4±0.3V (at 25℃). be done. (When a load is connected, the maximum voltage will further increase by 0.8V to 15.8V.
become. ) Therefore, the voltage at the output end of the auxiliary rectifier, which is at the same potential as the output end of the voltage regulator, also changes accordingly.

Therefore, when detecting an abnormality in the alternator by detecting a change in the output voltage at the output terminal of the auxiliary rectifier, the judgment reference voltage must be set to 15.8V or higher and 13V or lower, otherwise the abnormality will occur even when normal. Misjudgment may occur.

However, when determining abnormality by detecting the average output voltage of the auxiliary rectifier as in the conventional example above,
When the judgment level is set as above, the main rectifier,
Even when the auxiliary rectifier is disconnected, it may not be possible to detect this as an abnormality.

In other words, the abnormal voltage generated at the output terminal of the auxiliary rectifier during such an abnormality is at most 3 to 3 msec with a width of 0.1 m sec.
This is a ripple voltage of 15V, and if this is made into an average value voltage, it becomes 1 to 5V, and there are cases where the voltage does not exceed the above-mentioned determination level. By the way, if the set level is 15.8V and the reference voltage is 14.4V, a voltage of 1V will not exceed the detection level.
For this reason, it is not possible to accurately detect abnormalities. To avoid this, in the conventional example described above, an abnormality is determined based on a combination of conditions such as the number of ripples, ripple width, and average voltage of the output voltage at the output end of the main rectifier. However, the detection accuracy does not improve much.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and to accurately detect disconnections between the main rectifier and the auxiliary rectifier, which have the highest failure rate.

The above object of the present invention is to reduce the alternating current that flows due to the high voltage generated at the output end of the auxiliary rectifier when the main rectifier is disconnected, and the alternating current that flows from the storage battery through the charge lamp when the auxiliary rectifier disconnects. An integrating means for integrating, a means for generating an output voltage according to the maximum value of the current integrated value of the integrating means, and an alarm means for generating an alarm when the output voltage of the voltage generating means exceeds a predetermined value are provided. It is achieved by doing so.

An embodiment of the present invention will be described below based on the drawings. In FIG. 1, A shows an alternator control circuit incorporating an integrated circuit voltage regulator B, 1 is the armature winding of the alternator, 2 is the field winding of the alternator, and 3 is the alternator control circuit. A full-wave rectifier for AC output rectification (main rectifier), and 4 an auxiliary rectifier for excitation (auxiliary rectifier).

When the key switch 5 is turned on in the on-vehicle alternator, the resistor 6 in the voltage regulator B
Transistor 7 is turned on via , initial excitation current flows from storage battery 9 to field winding 2, and charging indicator light 8 lights up. When the rotational speed of the alternator increases, the voltage induced in the armature 1 is converted into a DC voltage by the full-wave rectifier 3, and the on-board storage battery 9 is charged by this voltage via the output terminals 10 and 11. . When the rotational speed of the armature increases and the induced voltage increases, a charging current begins to flow through the output terminal 11. In such a state, the voltage at the excitation voltage application terminal 12 also rises and becomes equal to the storage battery voltage, and the charging indicator light 8 goes out. On the other hand, voltage regulator B
is connected to the resistor 1 through the voltage detection terminal 13 of the regulator.
The voltage of the storage battery 9 applied to the terminals 4 and 15 is detected. The detection voltage is the specified value (14.4V±0.3Vat25
.degree. C.), the Zener diode 16 and the transistor 17 turn on, and conversely, the transistor 7 turns off, the current in the field winding 2 decreases, the output voltage of the alternator decreases, and voltage control is performed. As can be seen from the above explanation, an alternator with a built-in voltage regulator usually has positive and negative output terminals 10 and 11, an initial excitation/charge display terminal 12, and a voltage detection terminal 13 for external connection. There is.

In this embodiment, by detecting the voltage change at the initial excitation/charge display terminal 12, it is possible to easily diagnose the failure of the alternator.

A constant voltage circuit 19 generates a constant voltage and functions as a constant voltage power source for the operational amplifiers 20 and 21.

22 and 24 are capacitors, and 23 and 25 are resistors. The capacitor 22 and the resistor 23 constitute a filter circuit that passes only the alternating current generated at the terminal 12. The capacitor 24 and the resistor 25 form an integrator that integrates the alternating current passing through the filter circuit. 26 is a diode, 27 is a capacitor, and 21, 26, and 27 constitute a peak hold circuit. The output of diode 26 is connected to the non-inverting input of operational amplifier 21. 28 and 29 are resistors, and the operational amplifier 20 and the resistors 28 and 29 constitute a comparator. 30 is a resistor, 31 is a diode, and resistor 3
0. The light emitting diode 31 constitutes a display.

Next, the operation of the diagnostic device having the above configuration will be explained.

When the alternator A is normal, the initial excitation/charging display terminal 12 has a constant regulated voltage (14.4V±0.3Vat.25℃) set by the voltage regulator B.
occurs. When one of the auxiliary rectifiers 4 is disconnected, as shown in FIG. 3, an instantaneous voltage drop of about 1 msec occurs. When the voltage drops, current flows from the capacitor 9 in an alternating manner through the capacitor 22 and the resistor 23 to charge the capacitor 24, but the charge in the capacitor 24 is instantaneously discharged through the resistor 25. At this time, the terminal voltage of resistor 25 is
7, the output of the operational amplifier 21 becomes high level and the capacitor 27 is charged via the diode 26.

When one of the main rectifiers 3A is disconnected, an instantaneous ripple voltage with a width of about 1 msec is generated as shown in FIG. This is originally connected to terminal 11 via main rectifier 3A.
This is because the voltage that should be output to the main rectifier 3A is superimposed on the auxiliary rectifier 4 due to the disconnection of the main rectifier 3A.

In this case, it is calculated that the capacitor 24 is charged with the alternating current component due to the ripple voltage generated at the terminal 12, and the voltage drop that occurs at the resistor 25 when discharging via the resistor 25 becomes higher than the terminal voltage of the capacitor 27 as described above. The output of the amplifier 21 becomes high level and the capacitor 27 is further charged via the diode 26.

Thus, capacitor 27 has auxiliary rectifier 4
A peak voltage of the same polarity is generated and maintained even when the voltage at the terminal 12 drops due to a disconnection, and when a ripple voltage occurs due to a disconnection in the main rectifier 3A, and disconnections in the auxiliary rectifier 4 and the main rectifier 3A can be reliably detected.

Since the terminal voltage of this capacitor 27 has a value corresponding to the maximum value of the drop voltage and the maximum value of the ripple voltage at the terminal 12, the abnormality detection level is set high in consideration of voltage fluctuations at the normal voltage.
Even if set, a voltage sufficiently higher than this level can be obtained, and a disconnection can be detected early and reliably. Further, when the detection accuracy is set to the conventional example, the detection level can be set higher, and the possibility of false detection due to voltage fluctuation is reduced.

Thus, the terminal voltage of the capacitor 27 exhibits a value that is sufficiently higher than the voltage of the capacitor 27 when the alternator is normal. The voltage of this capacitor 27 is compared with a reference voltage value set by the regulator 19 and resistors 28 and 29, and if it is higher than the set voltage value, the operational amplifier 20 generates an output voltage, and the light emitting diode 31 lights up to indicate an abnormality in the alternator.

In this example, the alternator is left in the vehicle,
This has the effect of allowing easy failure determination.

According to the present invention, only the external terminal provided on the alternator is used while the alternator is mounted on the vehicle,
At least, there is an effect that disconnections in the main rectifier and the auxiliary rectifier can be detected early and reliably.

[Brief explanation of the drawing]

FIG. 1 is an electric circuit diagram of an AC electric machine equipped with an IC regulator and a failure diagnosis device of the present invention, and FIGS. 2 to 4 are voltage waveform diagrams. A...AC generator, B...IC regulator,
C...fault diagnosis device, 1...armature winding, 2...
Field winding, 3... Full-wave rectifier for AC voltage rectification (main rectifier), 4... Auxiliary rectifier for excitation (auxiliary rectifier), 12... Initial excitation and charging display terminal, 19...
... Regulator, 20, 21 ... Operational amplifier, 3
1... Light emitting diode.

Claims (1)

[Claims] 1 has a first rectifier whose output terminal is connected to the storage battery and a second rectifier whose output terminal is connected to the storage battery via a charge lamp, and the second rectifier has an output terminal connected to the storage battery.
In a fault diagnosis device that detects an abnormality in an alternator based on the output voltage of a rectifier, the alternating current component flows due to the high voltage generated at the output end of the second rectifier when the first rectifier is disconnected. and an integrating means for integrating the alternating current component of the current flowing from the storage battery through the charge lamp when the second rectifier is disconnected, means for generating an output voltage according to the maximum value of the current integral value of the integrating means, and this voltage. 1. A failure diagnosis device for an alternator, comprising an alarm means for generating an alarm when the output voltage of the generation means exceeds a predetermined value.