JPH0643827B2 - Engine starter protection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention is provided with an engine starter protection device, in particular, a rotation sensor for detecting the rotation speed of the engine starter, and the engine based on the detection signal of the rotation sensor. An engine starter configured to prevent the engine starter from being rotated in the opposite direction by stopping the power supply to the engine starter when the starter reaches a predetermined speed. The protective device detects an accident such as abnormal start of the engine starter, failure of the rotation sensor, disconnection of the output line, etc., and stops power supply to the engine starter even when the accident occurs. It relates to a protective device.

(Prior Art) In order to prevent the engine starter from being rotated in the opposite direction by the engine, it is necessary to disconnect the engine starter from the engine after the engine has started properly. Therefore, the engine starter rotation speed is detected, and when the rotation speed reaches a predetermined rotation speed, the power supply to the engine starter is stopped and the engine starter is disconnected from the engine. Engine starter protection devices such as that shown in FIG. 2 are known.

In the conventional example shown in FIG. 2, the engine starter 1 is disconnected from the engine based on the output voltage of the F / V converter 3 that converts the frequency of the detection signal of the rotation sensor 2 that detects the rotation speed into a voltage. Is configured. That is, when a key signal is input by turning on a key switch (not shown) for starting the engine starter 1, the output of the flip-flop 23 is output by the set circuit composed of the resistor 6 and the capacitor 7. Q is set to "H" level. Therefore, the output of the AND circuit 9 becomes “H” level, and the starter relay 12 is turned on via the relay driver 10, so that the engine starter 1 is started by being supplied with power from the power supply battery 11. . That is, the engine starter 1 is connected to an engine (not shown) to drive the engine.

After the start of the engine starter 1, the output voltage of the F / V converter 3 rises in response to the rise in the number of revolutions.
Until the reference voltage supplied to 1 is exceeded, the output of the comparator 21 is at the "L" level, so the flip-flop 23 is not reset. The reference voltage is set corresponding to the output voltage of the F / V converter 3 when the rotation speed of the engine starter 1 is a predetermined rotation speed (the rotation speed at which the power supply to the engine starter 1 is stopped). Therefore, when the engine starter 1 reaches a predetermined rotation speed, the output of the comparator 21 is inverted to the "H" level. As a result, the flip-flop 23 is reset, the Q output becomes "L" level, the output of the AND circuit 9 is also inverted to "L" level, and the power supply to the engine starter 1 is stopped. That is, when the rotation speed of the engine starter 1 reaches a predetermined rotation speed,
The power supply to the engine starter 1 is stopped and the engine starter 1 is disconnected from the engine.

(Problems to be Solved by the Invention) In the conventional example shown in FIG. 2, especially in the engine starter in which the one-way clutch is omitted, the rotation sensor 2
When an accident such as a failure of the engine or a disconnection of the wiring between the rotation sensor 2 and the F / V converter 3 occurs, the engine / starter can be disconnected from the engine even if the rotation speed reaches a predetermined rotation speed. Since it is impossible to do so, there is a problem that the engine starter is damaged by being rotated at high speed by the engine.

(Means for Solving Problems) An object of the present invention is to solve the above problems. Therefore, the engine starter protection device of the present invention is a rotation sensor for detecting the rotation speed of an engine starter. In the engine starter protection device configured to control the power supply to the engine starter based on the output voltage corresponding to the output from the rotation sensor, at least a predetermined first reference voltage and A first comparator for comparing the output voltage, a second comparator for comparing a predetermined second reference voltage with the output voltage, and a key signal for starting the engine starter. The output signal from the first comparator comprises at least a delay circuit for setting a time for substantially stopping the output signal of the second comparator. Is configured to invalidate the engine starter start control in the key signal, and as the back-up control,
It is characterized in that the engine starter start control by the key signal is invalidated by the output signal from the second comparator after the stop time by the delay circuit has elapsed. Hereinafter, description will be given with reference to the drawings.

(Embodiment) FIG. 1 is a circuit diagram showing an embodiment of an engine starter protection device of the present invention. Reference numeral 4 in the figure is the first comparator,
5 is a second comparator, 8 is a flip-flop, 13 is a diode, 14 is a capacitor, 15 is a differential shaper, 16
Is a NOR circuit, 17 to 20 are resistors, and other symbols correspond to those in FIG.

In FIG. 1, when the key signal is input, the output Q of the flip-flop 8 is set to "H" level by the set circuit composed of the resistor 6 and the capacitor 7. Therefore, the output of the AND circuit 9 becomes "H" level, and the starter relay 12 is turned on via the relay driver 10, so that the engine starter 11
Is activated by being supplied with power from the power supply battery 11. The output frequency of the rotation sensor 2 that detects the rotation speed of the engine starter 1 is converted into a voltage by the F / V converter 3 and supplied to the first comparator 4 and the second comparator 5.

On the other hand, at the time of the key signal, the output of the AND circuit 9 is at the “H” level, and therefore the output of the delay circuit formed by the resistor 17, the capacitor 14, the differential shaper 15 and the diode 13, that is, the differential shaper. The output of 15 stays at "H" level until the time determined by the resistor 17 and the capacitor 14 (hereinafter referred to as delay time) elapses. Therefore, regardless of the output of the second comparator 5, the output of the NOR circuit 16 is at "L" level and the flip-flop 8 is not reset at least until the delay time elapses. Output remains at "H" level.

The (-) terminal of the first comparator 4 has a first reference voltage Vref obtained by dividing the reference voltage Vref output from the F / V converter 3 by the resistors 18 and 19, 20.
₁ is being supplied. Further, the reference voltage Vref is applied to the resistors 18, 19 at the (-) terminal of the second comparator 5.
And the second reference voltage V ₂ divided by the resistor 20 is supplied. Then, the first reference voltage V ₁ is
The rotation speed of the engine starter 1 is set to correspond to the output voltage of the F / V converter 3 when the rotation speed at which the power supply to the engine starter 1 should be stopped is reached. The second reference voltage V ₂ is set to be at least smaller than the output voltage of the F / V converter 3 when the engine starter 1 normally starts and the delay time elapses.

Therefore, when the delay time elapses after the engine starter 1 is normally started and the output of the differential shaper 15 is inverted to the "L" level, the second comparator 5
Since the output of the above is already at the "H" level, the output of the NOR circuit 16 is maintained at the "L" level thereafter. Therefore, the flip-flop 8 is never reset. However, the starter relay 12
The engine starter 1 does not start normally due to a contact failure of the above, or an accident such as a failure of the rotation sensor 2 or a disconnection of wiring between the rotation sensor 2 and the F / V converter 3 occurs. When the delay time elapses, that is, when the output of the differential shaper 15 is inverted to the “L” level, the output of the second comparator 5 is at the “L” level, so the NOR circuit The output of 16 goes to "H" level, the flip-flop 8 is reset, and the Q output goes to "L" level. That is, when the accident has occurred, the output of the AND circuit 9 is inverted to the "L" level when the delay time has elapsed, so that the power supply to the engine starter 1 is stopped.

If the engine starter 1 is normally started and no accident such as a failure of the rotation sensor 2 has occurred, the output of the second comparator 5 is kept at "H" level at least after the delay time has elapsed. Therefore, the output of the AND circuit 9 is maintained at the "H" level and the power supply to the engine starter 1 is continued. After that, when the rotation speed of the engine starter 1 increases and reaches the rotation speed at which the power supply should be stopped, the output of the first comparator 4 is inverted to the “H” level. Therefore, at this time, the Q output of the flip-flop 8 is inverted to the "L" level, and the power supply to the engine starter 1 is stopped. However, when the above-mentioned disconnection accident occurs before the power supply is stopped, the output voltage does not appear in the F / V converter 3, so that the output of the second comparator 5 at that time. Becomes the “L” level. Therefore, NOR circuit 1
The output of the AND circuit 9 is inverted to "L" level via the 6-bit flip-flop 8. That is, power supply to the engine starter 1 is stopped in response to the occurrence of the accident.

(Effects of the Invention) As described above, according to the present invention, when the engine starter reaches a predetermined rotation speed, the power supply to the engine starter is stopped and the engine starter is abnormally started. The engine starter is rotated in reverse by making it possible to stop the power supply to the engine starter even when an accident such as a failure of the rotation sensor and a disconnection of the output line of the rotation sensor occurs. Can be prevented.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an embodiment of an engine starter protection device of the present invention, and FIG. 2 is a circuit diagram showing a conventional example of an engine starter protection device. In the figure, 1 is an engine starter, 2 is a rotation sensor, 3 is an F / V converter, 4 is a first comparator, 5 is a second comparator, 6 and 17 to 20 are resistors, 7 and 14 capacitors, 8 is a flip-flop, 9 is an AND circuit, 1
0 is a relay driver, 11 is a power supply battery, 12 is a starter relay, 13 is a diode, 15 is a differential shaper,
Reference numeral 16 represents a NOR circuit.

Claims (1)

[Claims] 1. An engine comprising at least a rotation sensor for detecting a rotation speed of an engine starter, and configured to control power supply to the engine starter based on an output voltage corresponding to an output from the rotation sensor.
In a starter protection device, a first comparator for comparing a predetermined first reference voltage with the output voltage, and a second comparator for comparing a predetermined second reference voltage with the output voltage , And at least a delay circuit for setting the time for substantially stopping the output signal of the second comparator after the key signal for starting the engine starter is input, and the output signal from the first comparator is provided. Is configured to invalidate the engine starter starting control by the key signal, and as the back-up control, the key signal is generated by the output signal from the second comparator after the stop time by the delay circuit elapses. An engine starter protection device, which is configured to disable engine starter start control.