JPH0564533B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is directed to a vehicle having an alarm control circuit that controls the power generation of a vehicle charging generator to maintain an appropriate charging state of a battery and warns of abnormalities in the charging system. The present invention relates to a charging control device for use in a vehicle.

[Conventional problems]

Conventional control devices detect power generation by turning off a lamp using the generator output, but when the battery load is small and a large generator output is not required, the generator output decreases and the lamp turns on incorrectly. There were times when I did.

In addition, Utility Model Application Publication No. 57-111034 is an improvement plan for the above-mentioned problem, but if the circuit added to improve the above-mentioned problem breaks down, there is a possibility that the function of the voltage control section will also be affected. be.

[Object of the present invention]

For this reason, the present invention adds a circuit to prevent false alarms from being issued by alarm means such as a power generation indicator lamp that informs whether power generation is normal or not, and even if this added circuit fails, power generation is still possible. The purpose of the present invention is to provide a charging control device for a vehicle that does not lose its original function of voltage regulation, which is to maintain the output voltage of a vehicle at an appropriate level.

[Summary of the invention]

The present invention has a switching means for intermittent current in the field winding according to the magnitude of the battery voltage,
It also has a voltage control circuit for controlling this switching means.

It also has an alarm means, for example, a lamp, which is activated when it detects that the power generation state is abnormal.

Furthermore, it is charged by the output voltage of the generator,
That is, it has an integration circuit that integrates the output voltage signal, and a power generation notification control circuit that detects the integrated voltage of the integration circuit and drives the alarm means in accordance with this integrated voltage.

However, if the battery remains in a fully charged state and the on-vehicle load is turned off, the alarm means may issue a false alarm.

In other words, in such a fully charged state, there is no need for the generator to charge the battery, and if the power consumption of the onboard load is low, there is no need to generate electricity, so the voltage regulation circuit does not energize the field winding. If the power is cut off, the output of the generator will decrease for a relatively long time, causing the alarm means to issue a false alarm.

In the present invention, a false alarm prevention circuit is added that prevents this false alarm and does not impair the voltage regulation function of the voltage regulation circuit even if the circuit itself breaks down. has come to have a function completely separate from the voltage regulation function.

By the way, in conventional systems, when such a false alarm occurs, the voltage adjustment function is directly affected, but with this, a failure in the false alarm prevention circuit is likely to cause a failure in the voltage adjustment circuit. .

In the present invention, when a false alarm occurs, that is, when the battery voltage is higher than the set value, the discharge time constant of the capacitor is increased to reduce the degree of drop in the capacitor voltage, and the transient This prevents the alarm means from issuing a false alarm due to a non-power generation state.

The drawings showing one embodiment of the present invention will be described above.

In the drawing, 1 is a battery, 2 is a key switch, and 3 is a three-phase AC generator driven by the vehicle engine, with a field winding 31 connected at one end to the battery 1, and a Y-connected stator winding. It consists of a wire 32 and a diode 33 which rectifies the three AC outputs of the stator winding 32 and has one end connected to ground and the other end connected to the positive terminal of the battery 1.

Reference numeral 4 denotes an alarm control circuit, which includes an excitation current control transistor 41a serving as a switching means having a collector connected to one end of the field winding 31, an anode connected to a connection point _P1 between the field winding 31 and the transistor 41a; The excitation current control circuit includes a diode 41b whose cathode side is connected to the positive terminal of 1.

Furthermore, it has a voltage adjustment circuit 42 consisting of resistors 42a, 42b, 42c, a Zener diode 42d, and a transistor 42e, and a known constant voltage circuit 4.
3a, comparators 43b, 43c, 43d, OR circuit 43e, inverter 43f, diode 43
g, transistors 43h, 43i, capacitor 4
3j, resistance 43k, 43l, 43m, 43n, 4
3o, 43p, 43q, 43r, 43t, 43
It has an alarm circuit consisting of u, 43x, 43y, and 43z.

44 is a load driving transistor for alarm, and 5 is an alarm lamp serving as an alarm means. And mainly output point P ₂ → resistor 43r → diode 43g
The path of → capacitor 43j → comparator 43d → OR circuit 43e → drive transistor 44 constitutes a power generation notification control circuit.

Next, the operation of the above configuration will be explained.

When key switch 2 is turned on and the engine has not started yet, output point P ₂ of generator 3 is 0.
[V], the voltage of the smoothing capacitor 43j to which the voltage is applied from the output point _P2 via the resistor 43r and the diode 43g becomes 0[V],
The output of the power generation detection comparator 43d becomes 1 level, which makes the transistor 44 conductive via the OR circuit 43e and the resistor 43z, lights up the lamp 5, and informs the driver that the generator 3 is not generating power.

Furthermore, since the generator 3 is not generating power, a breakdown current cannot be passed through the Zener diode 42d through the resistor 42a depending on the voltage of the battery 1, so the transistor 42c is turned off and the transistor 41a is turned on. , an excitation current is passed through the field winding 31.

Next, the engine rotates, so the alternator 3 that is linked to the engine also rotates, and the field winding 3
A generated voltage is generated in the stator winding 32 by the excitation current flowing through the stator winding 32 .

Then, the voltage of the smoothing capacitor 43j connected through the output point P ₂ of the stator winding 32, the resistor 43r, and the diode 43g is the reference voltage of the power generation detection comparator 43d (at the resistors 43x, 43y). When the voltage becomes higher than the determined voltage), the output of the power generation detection comparator 43d becomes 0 level, and
At this time, other battery overvoltage alarm comparator 4
3b, if the battery low voltage alarm comparator 43c does not detect any abnormality and each output shows a 0 level, the transistor 44 is turned off, the lamp 5 is turned off, and the generator 3 is generating power normally. Inform the driver.

Note that when the battery 1 is charged by the output of the generator 3 and the battery voltage exceeds a set value, that is, when the Zener diode 42d breaks down, the transistor 42e turns on.
The transistor 41a is turned off, the excitation current flowing through the field winding 31 decreases, and the output of the generator 3 also decreases.

Next, when the battery 1 exceeds the set value, that is, when the Zener diode 42d no longer breaks down, the transistor 41a turns on and increases the excitation current of the field winding 31, thereby increasing the generator 3.
The output of the battery 1 increases again, and by repeating the above operation, the voltage of the battery 1 is maintained at the set value.

Next, the operation of the alarm circuit 43 will be explained.

In the initial state where the key switch 2 is turned on as described above and the engine is not started, the output of the generator 3 is 0 [V]. Therefore, according to the operation described above, the drain resistor 41a is turned on, and the connection point P ₁ is turned on. Since the transistor 43h is turned on by the inverter 43f connected to this point _P1 in order to set it to the ground potential, the voltage of the capacitor 43j is 0.
[V]. Therefore, the output of the comparator 43d is 1
level, turning on the transistor 44 and lighting the lamp 5 (notifying that power is not being generated).

When the engine starts and the output voltage of the generator 3 rises, a current flows through the output point P ₂ , the resistor 43r, and the diode 43g, and when the voltage of the capacitor 43j exceeds the set value, the output of the comparator 43d becomes 0 level. Become.

At this time, the battery overvoltage alarm comparator 43b,
If the output of the battery low voltage alarm comparator 43c is at 0 level, the transistor 44 is turned off and the lamp 5
turns off (indicates that power is being generated).

When the output of the generator 3 is small, which was the first problem with the conventional example, for example, when the battery 1 is fully charged and the on-vehicle load L (e.g. motor, headlamp, etc.) no longer consumes power. , Batsuteri 1
As the voltage increases, even if the transistor 41a is turned off, the excitation current flowing through the field winding 31 gradually decreases via the flywheel diode 41b, so the output voltage of the generator 3 temporarily increases.
The voltage of battery 1 also temporarily rises above the set value.

Moreover, since the load current has become smaller, it takes several seconds to return to the normal battery voltage, and during this time, the transistor 41a is turned off and the field winding 31 is disconnected from the power supply, so the output of the generator 3 is Eventually, the amount decreases to a predetermined amount or less, causing the lamp 5 to erroneously light up in accordance with the above-mentioned operation, giving rise to a problem in which a notification is issued that power is not being generated even though the power generation state is normal.

To solve this problem, if the battery 10 voltage is higher than the set value, the Zener diode 42
Focusing on the fact that d breaks down and the transistor 42e turns on, and therefore the transistor 41a turns off, when the collector voltage of the transistor 41a (potential at point _P1 ) is high, the signal of this high collector voltage is inverted by inverter 43f,
This inverted signal turns off the transistor 43h and increases the discharge time constant of the capacitor 43j.

This reduces the degree to which the voltage of the capacitor 43j decreases, keeps the output of the comparator 43d at 0 level, and keeps the transistor 44 in the off state, thereby ensuring that the battery voltage is equal to or higher than the set value and the output of the generator 3 is This prevents the lamp 5 from being erroneously lit when the temperature drops. That is, the inverter 43
A false alarm prevention circuit is composed of the resistor 43u, the transistor 43h, and the resistor 43u.

Furthermore, the above configuration does not adopt the method of forcibly increasing the excitation current to prevent a drop in generator voltage when the output of the generator decreases, as in Japanese Utility Model Application Publication No. 57-111034. Even if the lamp erroneous lighting prevention circuits 43f and 43h fail, the voltage control functions such as stopping the power generation of the generator 3 and uncontrolled power generation will not be impaired.

In addition, even if the voltage control circuit 42 fails and the transistor 41a turns off, and the discharge time constant of the capacitor 43j becomes large due to the lamp erroneous lighting prevention circuits 43f and 43h, the Zener diode 42d of the power generation detection section continues to operate the generator 3. Since the output voltage of the capacitor 43j is detected, when the key switch is turned on, the voltage of the capacitor 43j is 0 [V], and the output of the comparator 43d becomes 1 level, turning on the transistor 44, so that a power generation failure can be warned by lighting a lamp.

Furthermore, if a failure suddenly occurs in the voltage control circuit 42 during power generation, a low battery voltage alarm is issued and the lamp is turned on.

For this reason, the battery 1 is
Detects the voltage of resistors 43h, 43l, 43
A reference voltage is formed by transistors 43i and 43n, and when the transistor 41a is on, the low level potential at point _P1 is inverted by an inverter 43f to turn on the transistor 43i.As a result, the reference voltage is lowered. 41a increases the reference voltage when it is off.

That is, when the transistor 41a is on, the reference voltage is lowered, and when it is off, the reference voltage is raised.

On the other hand, under normal conditions, when the transistor 41a is off, the voltage of battery 1 is the set value (for example, 14.5V).
This should be the above, and at this point, even if the reference voltage for the battery low voltage alarm is high (for example, 13V), a false alarm will not occur.

Further, the transistor 41a is turned off due to a failure in the voltage control circuit 42 as described above, and as a result, when power generation is stopped, the reference voltage is increased and a low voltage alarm can be issued at an early stage.

Furthermore, when the power consumption of the on-vehicle load is large, even if the transistor 41a is on, the load current may become larger than the output capacity of the generator 3 and the voltage of the battery 1 may decrease. By turning on, the reference voltage mentioned above is lowered, that is, the battery low voltage alarm value is lowered (for example, 8V) to prevent false alarms.

Regarding the battery overvoltage alarm, as mentioned above, when a large current load is cut off, the battery voltage temporarily increases. It is set high when the transistor 41a is off and low when it is on to prevent false alarms and to provide an early warning in the event of an abnormality (for example, when the battery is overcharged due to a short-circuit failure of the transistor 41a).

[Effects of the present invention]

As described above, in the present invention, when the switching means is turned off, such as during a transient non-power generation state, the discharging time constant of the integrating circuit is increased to make it difficult to discharge the charge of the capacitor. Since the voltage of the capacitor decreases and the failure of power generation is prevented from being reported, false alarms from the alarm means can be prevented. Moreover, at this time, since the operation of the voltage control circuit that directly controls the current of the field winding is not changed in order to prevent false alarms of power generation failure, the false alarm prevention circuit that prevents false alarms from the alarm means does not change. Even if a failure occurs, the failure does not spread to the voltage control circuit, so there is an advantage that the battery will not be damaged.

[Brief explanation of drawings]

The drawing is an electrical wiring diagram of a vehicle charging control device showing one embodiment of the present invention. 4...Alarm control circuit, 5...Alarm means, 1...
Battery, 31... Field winding, 41a... Switching means, 43j... Capacitor, P ₂ , 43
r, 43g, 43j, 43d, 43e, 44...
Power generation notification control circuit, L... Vehicle load, 43... Voltage adjustment circuit, 43f, 43u, 43h... False alarm prevention circuit, 3... Generator, 4... Alarm control circuit.

Claims (1)

[Scope of Claims] 1. Switching means 41a that maintains the output voltage of the alternator at a set voltage by intermittent current in the field winding of the alternator that charges the battery of the vehicle and supplies power to the on-vehicle load; A voltage adjustment circuit 42 that controls the switching means 41a according to the battery voltage, a capacitor 43j that takes the output voltage of the alternator as an input signal and integrates the input signal, and a discharge section 43t provided in parallel with the capacitor. a power generation alarm control circuit that has a circuit and determines whether power generation is good or bad based on the integrated voltage of the integrating circuit; an alarm means 5 for notifying the user, and increasing the discharge time constant of the discharging section of the integrating circuit in synchronization with the off-operation of the switching means, and increasing the discharging time constant of the discharging section of the integrating circuit in synchronization with the on-operation of the switching means; False alarm prevention circuit 43 that reduces the time constant and prevents false alarms from the alarm means 5
A vehicle charging control device characterized by comprising: f, 43u, and 43h.