JPS6212864Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to a safety device for an automobile fuel pump, in particular, it supplies fuel to the engine only when the automobile engine is started and when the engine is rotating, and when the engine is stopped, the fuel supply to the engine is cut off so that the fuel pump is not used. The present invention relates to a safety device for a fuel pump for an automobile that prevents accidents by not supplying fuel.

In conventional automotive fuel pump safety devices, when the engine starter is activated, the starter activation detection signal is sent to the starter terminal of the ignition switch to activate the fuel pump, as shown in Japanese Utility Model Publication No. 52-18668. It was taken out from. For this reason, the wiring for the operation detection signal from the starter terminal was not only connected between the ignition switch on the main body and the starter, but was also connected to other power lines via electronic components and routed around various parts of the vehicle body. This was extremely dangerous because if the electronic components were destroyed in shoot mode, the starter would operate even if the ignition switch was not in the starter position. Conversely, if the operation detection signal wiring is jammed or otherwise shorted to ground, no voltage will be applied to the starter, making it impossible to move the starter, and not only will the engine not be able to start, but there will usually be a fuse in the starter starting circuit. Because they were not installed, there was an increased risk of a fire in the vehicle due to electric wires being burnt out by the shot, creating a safety problem. or,
Conventional fuel pump safety devices require the use of multiple relays, resulting in a large size and
It is heavy and expensive, and since the relay itself uses switching contacts, it is prone to poor contact due to oxidation of the contacts. Furthermore, since engine rotation is detected by the amount of power generated by the alternator or by a hydraulic switch, if the fan belt attached to the alternator breaks or if the hydraulic switch malfunctions or malfunctions, it will be detected. Another drawback was that the fuel supply was cut off.

SUMMARY OF THE INVENTION The object of the present invention is to eliminate the above-mentioned drawbacks, and to provide a safety device for an automobile fuel pump that is simple in construction, small in size, lightweight, and provides reliable fuel supply at an inexpensive price.

The present invention includes an ignition switch having an ignition terminal, an accessory terminal, and a starter terminal, a series connection circuit of a charge lamp and an alternator connected to a DC power source via the ignition switch, and a series connection circuit of a charge lamp and an alternating current generator connected in parallel to the series connection circuit. a series connection circuit of a connected oil pressure warning light and oil pressure switch;
In a safety device for an automobile fuel pump, which includes a fuel pump control circuit connected between both series-connected circuits and the fuel pump, the fuel pump control circuit includes first and second transistors and a relay. the first transistor is connected in series with the coil of the relay between the ignition terminal of the ignition switch and the DC power supply, and the base of the first transistor is connected to the connection point of the alternating current generator and the charge lamp and the A second transistor is connected between the base of the first transistor and the ignition terminal of the ignition switch, and the base of the second transistor is connected to the connection point of the oil pressure switch and the oil pressure warning light, respectively. The relay is connected to an accessory terminal, and a contact point of the relay is connected between an ignition terminal of the ignition switch and the fuel pump.

Embodiments of the present invention will be described below with reference to the drawings.

The safety device for an automobile fuel pump according to the present invention includes a battery 1 which is a DC power source, an accessory terminal 2, an ignition terminal 3, a starter terminal 25,
Ignition switch 22 having an off terminal 26
, an alternator 6 that detects the rotation of the engine, a hydraulic switch 8 , a fuel pump 21 , and a fuel pump control circuit 24 .

That is, the positive terminal of the battery 1 is connected to the shorting plate 23 of the ignition switch 22, and the ignition terminal 3 of the ignition switch 22 is connected to the battery via a series connection circuit of a charge lamp 4, a resistor 5, and an alternator 6 connected in parallel. Connect to the negative terminal of 1. A series connection circuit of the oil pressure warning light 7 and the oil pressure switch 8 is connected in parallel to this series connection circuit. The fuel pump control circuit 24 includes two transistors 1
4 and 17, relay and two voltage dividers 9, 10, 1
1, 12, and 13. That is, between the ignition terminal 3 of the ignition switch 22 and the negative terminal of the battery 1, a series circuit of resistors 9, 10, and 11, which is a first voltage divider, and a series circuit of the first transistor 17 and the relay coil 16 are connected in parallel. A series circuit of resistors 12 and 13, which is a second voltage divider, and a second transistor 14 are connected between the base of the first transistor 17 and the ignition terminal 3.
and a series circuit of resistor 15 are connected in parallel.
Further, the base of the first transistor 17 is connected to the connection point between the resistors 10 and 11, and the connection point between the resistors 9 and 10 is connected to the connection point between the charge lamp 4 and the alternating current generator 6. Furthermore, the connection point of the resistors 12 and 13 is connected to the connection point of the oil pressure warning light 7 and the oil pressure switch 8. The base of the second transistor 14 is connected directly to the accessory terminal 2 of the ignition switch 22 via a resistor 18 and to the negative terminal of the battery 1 via a resistor 20. Further, a fuel pump 21 is connected in parallel to the relay coil 16 and first transistor 17 connected in series via a relay contact 19.

The operation of the safety device for an automobile fuel pump constructed in this manner will be described below.

Now, when the shorting plate 23 of the ignition switch 22 is switched to the accessory position, the battery 1 and the accessory terminal 2 are connected, but the control circuit 24 does not operate because current only flows through the resistor 20.

When the shorting plate 23 of the ignition switch 22 is switched to the ignition position, the battery 1, accessory terminal 2, and ignition terminal 3 are connected. At this time, since the emitter and base of the second transistor 14 are at the same potential, the second transistor 14 does not operate and remains in an off state. Also, at this time, since the engine is not rotating, there is almost no potential difference between the L terminal and E terminal of the alternator 6, so the charge lamp 4 remains lit and the current also flows from the ignition terminal 3.
It simply flows from there through the resistor 9 to the alternator 6. In this case as well, since the engine is not rotating as described above, the oil pressure switch 8 remains closed, the oil pressure warning light 7 also remains lit, and the current also flows from the ignition terminal 3 to the resistor 1.
It simply flows to the oil pressure switch 8 via 2. Therefore, the first transistor 17 remains in an off state since no current flows through its base.

When the shorting plate 23 of the ignition switch 22 is switched to the starter position, the battery 1 is connected to the ignition terminal 3 and the starter terminal 25,
The current flows from the ignition terminal 3 to the emitter/base of the second transistor 14, through the resistor 18, and then to the resistor 2.
Therefore, the second transistor 14 is turned on, and the main current flows from the emitter to the collector of this transistor 14. This collector current flows through the resistor 15 to the base-emitter of the first transistor 17, thereby turning the first transistor 17 on. When the first transistor 17 is turned on, the main current from the ignition terminal 3 flowing through its emitter-collector will flow through the relay coil 16, thereby closing the relay contact 19.

Therefore, current flows through the fuel pump 21 from the ignition terminal 3 through the relay contact 19, and the fuel pump 21 is thereby activated to supply fuel to the engine.

When the engine starts, the alternator 6 starts generating electricity, the voltage between its L terminal and E terminal increases, and the charge lamp 4 turns off. At this time, when the ignition switch 22 is returned to the ignition position, the emitter and base voltages of the second transistor 14 become the same potential and turn off, but the first transistor 17 has the alternator 6 connected to its base. Since current flows from the L terminal through the resistor 10, the on state is maintained. Also, as the engine rotates, the oil pressure increases, so the oil pressure switch 8 opens and the oil pressure warning light 7 turns off. Since current flows, the first transistor 17 remains in the on state. Therefore, even if the shorting plate 23 of the ignition switch 22 is returned from the starter position to the ignition position, the second transistor 1
4 is turned off, the first transistor 1
7 is kept on by a signal from the alternator 6, a signal from the hydraulic switch 8, or both signals, so that the relay also remains energized and continues to operate the fuel pump 21.

If the engine stops for some reason,
When the alternator 6 stops, the oil pressure decreases and the oil pressure switch 8 closes again, and the first transistor 1
7, the first transistor 17 is turned off in the same manner as described above, current no longer flows to the relay coil 16, the relay contact 19 is opened, the fuel pump 21 is stopped, and the engine is turned off. Stop fuel supply to.

The safety device for a fuel pump for an automobile based on the present invention constructed as shown in the embodiments described above has the following advantages.

Since the starter's operation detection signal is extracted from the combination of the ignition terminal and accessory terminal without depending on the starter terminal, there is no need to wire the operation detection signal from the starter terminal, and therefore it is difficult to imagine when wiring. It is extremely safe as it can prevent malfunction of the starter due to contact with other power supplies, burnout due to wires getting caught, and fires caused by this.

Reliability can be increased since only one relay needs to be used and switching contacts are only required on the suction side.

Since non-contact electronic components such as semiconductor devices are used to drive the relay, there is no mechanical wear on the components and the lifespan of the components can be extended.

Since the circuit configuration is extremely simple, it can be integrated with a relay, making it possible to reduce the size and weight, and also simplify the wiring on the vehicle side.

Since no special electronic components are used, no special adjustments are required, and the device is inexpensive and easy to install.

Since the engine rotation detection signal is extracted as a logical product from both the power generation amount of the alternator and the hydraulic switch, it is highly reliable and safe.

[Brief explanation of the drawing]

The drawing is a connection layout diagram showing the configuration of a safety device for an automobile fuel pump in an embodiment of the present invention. 1...Battery, 2...Accessory terminal (2
2), 3...Ignition terminal (22), 4...Charge lamp, 5, 9, 10, 11, 12, 1
3, 15, 18, 20... Resistor, 6... Alternator, 7... Oil pressure warning light, 8... Oil pressure switch, 1
4... Second transistor, 16... Relay coil, 17... First transistor, 19... Relay contact, 21... Fuel pump, 22... Ignition switch, 23... Short circuit plate (22), 24... …
Fuel pump control circuit, 25...Starter terminal (2
2), 26...off terminal (22).

Claims (1)

[Scope of utility model registration request] An ignition switch having an ignition terminal, an accessory terminal, and a starter terminal, a series connection circuit of a charge lamp and an alternator connected to a DC power source via the ignition switch, and an alternator connected in parallel to the series connection circuit. A safety device for an automobile fuel pump comprising a series connection circuit of an oil pressure warning light and an oil pressure switch, and a fuel pump control circuit connected between both series connection circuits and the fuel pump, wherein the fuel pump control circuit is connected to the fuel pump. , first and second transistors, and a relay, the first transistor being connected in series with the coil of the relay between the ignition terminal of the ignition switch and the DC power supply,
The bases of the transistors are connected to the connection points of the alternator and the charge lamp and the connection points of the oil pressure switch and the oil pressure warning light, respectively, and a second transistor is connected between the base of the first transistor and the ignition terminal of the ignition switch. connection,
A fuel pump for an automobile, characterized in that a base of the second transistor is connected to an accessory terminal of the ignition switch, and a contact of the relay is connected between an ignition terminal of the ignition switch and the fuel pump. Safety device.