JPS63284052A - Automatic electric power switch for vehicle - Google Patents

Abstract

PURPOSE:To avoid the starting-impossible state of a starter by automatically suspending the supply of electricity when the battery voltage lowers below and allowable range because of the continuation of putting-ON state of a headlamp or a small lamp during the engine stop or the use of cassette deck, etc. CONSTITUTION:The first opening/closing element 4 in always opened state is interposed between a bettery 1 and the load such as a headlamp, small lamp and a cassette deck, and the second opening/closing element 4a in always opened state is interposed between the battery 1 and the ACC contact point of an ignition switch 2. A voltage level judging means 3 is connected with the ACC contact point, and it is judged if the battery voltage lowers below a prescribed value or not. When it is judged that the battery voltage lowers below the prescribed value, the first and second opening/closing elements 4 and 4a are opened to cut off the electric conduction to the load, and an alarm means 5 is operated to perform alarm of the reduction of the voltage level.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an automatic power switch for a vehicle that automatically detects a drop in battery voltage of a vehicle and cuts off power supply to a load.

[Problems to be solved by the prior art and the invention] Conventional equipment to prevent battery consumption monitors the battery voltage and issues a warning when the voltage falls below the minimum specified voltage that can reliably start the starter motor. Various systems are well known, such as warning the driver if he or she forgets to turn off the light or remove the key. Furthermore, devices are well known that detect the absence of passengers based on sounds and vibrations inside the vehicle and automatically interrupt power supply.

However, there has been no suitable device that allows the battery to be used even when the engine is stopped and automatically cuts off the power supply only when the voltage drops below a specified level.

In view of this, the present invention automatically interrupts the battery power supply when the voltage drops below the specified voltage while the battery is in use with the ignition switch in the OFF position, and also reduces the power consumption of the circuit for this purpose. When I lost it and set the ignition switch to the ACC position to confirm,
An object of the present invention is to provide an automatic power switch for a vehicle capable of obtaining a warning that the voltage has decreased.

[Means for solving problems]

To achieve this objective, the present invention provides a normally open primary battery inserted between the battery l and the load, as shown in FIG.
A normally open second switching element 4a inserted between the switching element 4 and the ACC contact of the battery l and the ignition switch 2, and an alarm means 5 that issues an alarm with light, sound, etc.
It connects to the CC contact to determine whether the battery voltage goes above or below a predetermined level, and when it goes above, closes the first and second switching elements 4.4a, and when it goes below, activates the alarm means 5. The voltage level determining means 3 is configured to determine the voltage level.

[Effect]

When ignition switch 2 is set to the ACC position,
The battery voltage supplied through the ACC contact is compared in the voltage level determining means 3 with a reference voltage corresponding to the lowest permissible voltage at which the starter can be operated. If there is a margin, the output signal closes the first and second switching elements 4.4a. As a result, power is supplied to the load, and the battery voltage is also supplied to the voltage level determining means 3 through the switching element 4a, so that a self-holding state is established, and even if the ignition switch 2 is returned to the OFF position, the switching element 4 .4a is always kept closed.

Therefore, while the engine is stopped, various loads such as a clock, radio, lamp, etc. can be used by operating the associated switches. On the other hand, if the battery voltage falls below the reference voltage in this state, the voltage level determining means 3 opens the switching element 4.4a and interrupts the power supply.
The self-holding state described above is also released and the voltage level determining means 3
Power consumption will also be eliminated.

In this open state, turn the ignition switch 2 to A.
When the CC position is set to t, the battery voltage is supplied to the voltage level determining means 3, and it is determined that the voltage is below the reference voltage.
Due to the detection, the alarm means 5 is activated.

When the ignition switch 2 is set to the ST position t and returned to the ON position after operating the alternator, the battery voltage that has risen from the ACC contact is determined again by the voltage level determining means 3.
is supplied to make the switching element 4.4a self-maintain in the closed state again.

Embodiment of the Invention FIG. 2 shows an embodiment of the invention using a commercially available integrated circuit 10 indicated by a dashed line.

In the figure, a voltage divider 11 is supplied with power from the battery 8 from the ACC position of the ignition switch 9, a comparator 12 that compares the divided voltage with the output voltage of a reference voltage generation circuit 13, and an inverter 14. Transistor Trl, T
r2 and resistor R1 constitute voltage level determining means. When the input voltage of the voltage divider 11 exceeds 11.5V, the comparator 12 uses its output signal to turn off the transistor Tri and turn on the transistor Tr2 through the inverter 14.

A blinking oscillation circuit 15, a capacitor CI that defines the blinking cycle, and a transistor Tr3. Tr41, resistance R
2. It constitutes a blinking alarm means with LEDI.

When the input voltage to the voltage divider 11 becomes less than ti, sv, the comparator 12 activates the blinking oscillation circuit 15, and the constant voltage circuit 1
The LEDI performs a blinking operation using 8 as a power source.

Capacitor C2 cooperates with diode D2 to form voltage divider 1
This is a voltage holding circuit that holds the input voltage to 1 for a certain period of time.

20 is a relay for load power supply and self-holding that has two normally open contacts 20a and 20b.

21 is a direct connection switch for supplying power to the load regardless of the battery voltage.

The operation of the vehicle automatic power switch configured as described above is as follows.

When the battery 8 is newly connected, by setting the -B ignition switch 9 to the ACC position t, the output signal of the comparator 12 turns on the transistor Tr2, activates the relay 20, and connects the load through the contact 20a. Let the power supply be carried out. After that, turn the ignition switch 9 to O.
Even at the FF level t, the relay 20 is maintained in the closed state by the self-holding action through the contact 20b.

In this state, the battery voltage is +1. When the voltage drops below SV, the comparator 12 turns off the transistor Tr2, opens the relay 20, and activates the blinking oscillation circuit 15 to blink the LEDI, thereby warning of a voltage drop. This warning continues until the charging voltage of capacitor C2 falls below a predetermined voltage. Even after the warning ends, if you turn the ignition switch 9 to the ACCCC position, the LED
I performs a blinking operation.

In this state, it is impossible to connect the load, and the batch
consumption of the starter is prevented and the starter is kept ready for operation. However, if necessary, for example, to turn on the parking light when parking at night, it is possible to prepare for an emergency by turning on the switch 21. Further, it is conceivable that the reference voltage may be set with a margin in consideration of such matters. Battery voltage is 11. When the engine is operated again with the voltage below SV and the battery voltage is increased by the alternator, the comparator 12 detects the voltage increase and puts the relay 20 into the self-holding state again.

〔Effect of the invention〕

As described above, according to the present invention, if the battery voltage falls below the permissible range due to forgetting to turn off the headlamp, small lamp, etc. or using a cassette deck while the engine is stopped, the power supply is automatically interrupted, making it impossible for the starter to start. Avoid. Further, during this time, the power supply to the circuit portion that causes such an effect is also interrupted by utilizing the self-holding effect, thereby saving power. Furthermore, such a low battery voltage state can be confirmed without consuming power by momentarily setting the ignition switch to the ACC position.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a circuit configuration of an automatic power switch for a vehicle according to the present invention, and FIG. 2 is a diagram showing a circuit configuration according to an embodiment thereof.

Claims (1)

[Claims] A normally open first switching element inserted between the battery and the load, and the battery and the ignition switch.
A normally open second switching element inserted between the CC contacts, an alarm means for issuing an alarm, and determining whether the battery voltage supplied from the ACC contact is above or below a predetermined level, and closing the first and second switching elements,
An automatic power switch for a vehicle, comprising voltage level determining means that activates the alarm means when turned down.