JPH08114179A - Electromagnetic pump and control circuit therefor - Google Patents

Abstract

PURPOSE: To provide a small and light electromagnetic pump which is constituted to improve startability of an engine, simplify a control circuit by using a timer, and provide a fuel cut function. CONSTITUTION: A control circuit for an electromagnetic pump comprises a first mono-stable multivibrator circuit 10 operated by converting the pulse signal of an ignition coil 4 into a trigger signal; a astable multivibrator circuit 11 to output a plurality of pulses in the output continuous period of the first astable multivibrator circuit 10; and a switching element 9 to control reciprocation operation of a plunger through an exciting coil 7 by means of an output from the astable multivibrator circuit 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control circuit of a plunger type electromagnetic pump for feeding fuel to an internal combustion engine or the like.

[0002]

2. Description of the Related Art FIG. 10 shows, for example, Japanese Patent Publication No. 2-153254.
A circuit diagram showing a control circuit configuration of a conventional plunger type electromagnetic pump used in the internal combustion engine shown in Japanese Patent Publication No.
FIG. 11 is a sectional view showing the structure of the same electromagnetic pump. In the figure, 1 is a battery, 2 is a fuse, 3 is an ignition switch, 4 is an ignition coil, and 5 is a transistor igniter.

Reference numeral 106 denotes an electromagnetic pump control circuit, which includes a transistor 107, a signal coil 108, an exciting coil 109,
It has diodes 110 and 111, a thyristor 112, a surge absorber 113 for protecting the transistor 107, a Zener diode 114, and resistors 115-117.

Reference numeral 120 is a cylindrical plunger made of a magnetic material, and 121 is a spring for returning the plunger 120.
Reference numerals 122 and 123 are an intake valve and a discharge valve that make the reciprocating motion of the plunger 120 act as a pump.

Next, the operation will be described. When the engine (not shown) rotates and the transistor igniter 5 performs on / off operation, a pulse is generated at a point A of the ignition coil 4 shown in the figure (this pulse is temporarily referred to as an ignition pulse). This ignition pulse is supplied to the gate of the thyristor 112 via the resistor 115 and the Zener diode 114, and the thyristor 112
Turns on. This turn-on causes resistor 117,
Current flows from the battery 1 to the signal coil 108 and the excitation coil 109, and the transistor 107 and the signal coil 108
The blocking oscillator circuit (which is electromagnetically coupled to the exciting coil 109) and the exciting coil 109 starts oscillation.

Due to this oscillation, the exciting coil 109 attracts the plunger 120, the spring 121 returns, and the plunger 12
Move 0 back and forth. When the thyristor 112 is normally turned on, it stays on until the commutation operation is forced, but the resistor 117 is set so that the anode current of the thyristor 112 is less than the holding current. Turns off naturally without the need for a commutation circuit, and the blocking oscillator circuit causes the plunger 120 to reciprocate several times and then stop oscillating.

That is, the thyristor 112 is turned on for a fixed time by the ignition pulse, and as long as the ignition pulse is continuously input, the thyristor 112 remains in the on state. And when the vehicle is stopped,
When the engine stops due to overturning or collision and the ignition pulse disappears, the thyristor 112 is turned off, the reciprocating motion of the plunger 120 is stopped, the fuel supply is stopped, and the fuel cutoff function is executed. .

[0008]

As described above, the conventional electromagnetic pump is configured to operate only during cranking of the engine in which the transistor igniter 5 is in the on / off state and when an ignition pulse is generated during engine rotation. There is. However, during cranking, the ignition pulse that occurs at point A is infrequent and the number of reciprocating movements of the plunger 120 is small, so there is less fuel to be fed to the engine and the engine startability is poor. was there.

Further, since the oscillation circuit requires two coils, the signal coil 108 and the exciting coil 109, there is a problem that the space for the coil winding becomes large and the external dimensions of the electromagnetic pump become large.

The present invention has been made to solve the above problems, and is to obtain a control circuit capable of maintaining a high feeding ability even during cranking and operating with one coil, and to be configured with one coil. The purpose is to provide a small electromagnetic pump. Also, a capacitor discharge ignition device (CDI) used in a relatively small engine is used.
It is also intended to provide an electromagnetic pump control circuit applicable to

[0011]

A control circuit for an electromagnetic pump according to the present invention includes a first monostable multivibrator circuit which operates by using a pulse from an ignition coil as a trigger signal, and the first monostable multivibrator circuit. It is provided with an astable multivibrator circuit which operates while the output of the circuit continues and a switching element which excites an exciting coil by the output of the astable multivibrator circuit.

Further, an ignition coil connected to the capacitor discharge ignition device is provided, and a zener diode is provided in series between the ignition coil and the first monostable multivibrator circuit.

Further, the astable multivibrator is constructed by using a second timer IC capable of adjusting the cycle of the output pulse by an external signal, and also converts the signal pulse of the ignition coil into a pulse having a constant time width. The second monostable multivibrator and the low-pass filter for averaging the outputs of the second monostable multivibrator are provided.

A plurality of diodes are connected in series in parallel with the exciting coil.

Further, a plurality of diodes are connected in series to the base terminal of the switching element for controlling the current flowing in the exciting coil.

Further, a diode is connected between a connecting portion of a plurality of diodes connected in series to the control input of the switching element and the collector of the switching element.

The astable multivibrator circuit has a time constant circuit composed of a resistor and a capacitor and a second timer I.
Further, this resistor is configured by connecting a first resistor and a second resistor in which diodes are connected in parallel to each other in series.

Further, a triac element that uses a negative potential signal pulse from the ignition coil as a trigger signal via a zener diode, and a blocking oscillation circuit that is oscillated by an output signal from the triac element and reciprocates a plunger. Be prepared.

The electromagnetic pump according to the present invention has one coil which is not electromagnetically coupled to other coils.

[0020]

In the electromagnetic pump control circuit configured as described above, the first monostable multivibrator circuit, which operates by using the pulse from the ignition coil as a trigger signal, operates the electromagnetic pump for a certain period of time when the ignition switch is turned on. Then, the fuel is fed to the engine in advance before starting. Furthermore, since the astable multivibrator circuit operates only during the output continuation period of the first monostable multivibrator circuit, the electromagnetic pump is stopped by the interruption of the pulse from the ignition coil.

The Zener diode provided between the ignition coil and the first monostable multivibrator circuit prevents malfunction of the electromagnetic pump due to noise from other electric components mounted on the vehicle.

Further, since the control voltage of the second timer IC constituting the astable multivibrator circuit is changed in proportion to the engine speed, the number of times the plunger operates can correspond to the engine speed. It will be possible.

Also, by connecting a plurality of diodes in series in parallel with the exciting coil of the electromagnet section, the circulating current flowing through the exciting coil is reduced, and the electromagnetic force holding the plunger is reduced, so that the plunger can operate at high speed. Allows reciprocating motion.

Further, by connecting a plurality of diodes in series to the base of the switching element for controlling the current flowing in the exciting coil, the operation of the control circuit at high temperature is stable.
Be certain.

Further, by connecting the diode between the connecting portion of the plurality of diodes connected in series to the base of the switching element and the collector of the switching element, the switching element can be protected when the battery is reversely connected. .

Furthermore, the resistor of the time constant circuit which comprises the resistor and the capacitor which constitute the astable multivibrator circuit, by connecting the diode in parallel with this resistor, bypasses the resistor when charging the capacitor. HI of the output of the astable multivibrator circuit
The ratio of time to LO time is set so that the length of HI time is shorter than the length of LO time.

The triac element activates the blocking oscillator circuit. The electromagnetic pump can be operated at the timing when the signal pulse from the ignition coil has a negative potential. Further, the Zener diode prevents the electromagnetic pump from malfunctioning due to noise from other electric components mounted on the vehicle.

An electromagnetic pump having only one coil is
The outer shape is miniaturized.

[0029]

【Example】

Example 1. 1 is a control circuit diagram of an electromagnetic pump according to a first embodiment of the present invention, and FIG. 2 is a sectional view of the electromagnetic pump of the present invention. In the figure, 1 to 5 and 120 to 123 are the same as the conventional electromagnetic pump and its control circuit shown in FIGS. 10 and 11, and the description thereof is omitted. 6 is an electromagnetic pump of the present invention, 7
Is an exciting coil, 8 is a transistor, 9 is a transistor as a switching element, 10 and 11 are 555 type first and second timer ICs, 12 to 19 are diodes,
20 is a Zener diode, 21 to 28 are resistors, and 29 to 35 are capacitors.

FIG. 3 is an operation time chart of the control circuit of FIG. FIG. 4 is a block diagram showing the circuit of FIG. 1 for convenience of explanation.

Next, the operation of the circuit of FIG. 1 will be briefly described with reference to the block diagram of FIG. 4, and then the detailed description of FIG.
When the ignition switch 3 is closed, or when the transistor igniter 5 is turned on and off to start the engine, the voltage of the ignition coil 4 and further the voltage applied to the capacitor 29 of FIG. 4 changes, and the pulse signal changes. Sent to Monostable Multi 10.

Each time the pulse signal is sent, the first monostable multi 10 outputs a signal for a certain period (several seconds) (this is called a first pulse signal). The non-stable multi 11 continuously oscillates a pulse having a short period while the first monostable multi 10 outputs the first pulse signal (this is referred to as a second pulse signal). The second pulse signal causes the exciting coil 7 to be turned on and off at a constant cycle via the transistor 9, and the pump 6 is driven.

Next, description will be made with reference to FIGS. First, when the ignition switch 3 is turned on for starting the engine (FIG. 3, t ₀ ), a voltage is applied from the battery 1 to the point A via the fuse 2 and the ignition coil 4.
At this time, the transistor igniter 5 is off. Therefore, a current flows to the base of the transistor 8 through the resistor 21 and the capacitor 29, the transistor 8 is turned on, and the TR1G terminal of the timer IC 10 is set to the LO potential.

The timer IC 10 has a TR1G terminal voltage of Vc
When the voltage becomes 1/3 or less of the c voltage, a monostable multivibrator circuit that outputs the HI voltage from the OUT terminal with a time constant consisting of the resistor 23 and the capacitor 31 is configured, and the predetermined constant determined by the time constant is set. Period (Fig. 3 (b) t _{0 to} t ₁ ),
A voltage is applied to the RESET terminal of the timer IC11.
For this reason, the ignition coil 4 is
If the input from is continued, RE of timer IC11
The voltage is continuously applied to the SET terminal.

The timer IC 11 constitutes an astable multivibrator circuit including a time constant circuit in which resistors 24 and 25, a capacitor 33, and a diode 13 are combined.
While the voltage from the timer IC 10 is being applied to the ESET terminal, a pulse voltage signal (second pulse signal) of a constant cycle is output from the OUT terminal with a time constant consisting of the resistors 24 and 25 and the capacitor 33 as shown in FIG. ) Output.

When the output signal of the timer IC 11 is HI, the base current of the transistor 9 flows through the resistors 26 and 27 and the diodes 15 and 16 to make the transistor 9 conductive, so that the exciting coil 7 is energized. Further, at the time of LO, a current flows to GND through the resistors 26 and 27, the diode 14 and the internal circuit of the IC 11, so that the base current is not supplied to the transistor 9 and the exciting coil 7 is not energized. This is shown in FIG.

The diode 16 has a large voltage drop between the OUT terminal of the timer IC 11 and the GND when operating at a high temperature, and the resistor 26 and
27, a bias diode inserted to prevent the base current from flowing to the transistor 9 through the diodes 15 and 16, and ensures the switching operation of the transistor 9 at a high temperature.

The diode 17 is inserted between the connection between the diodes 15 and 16 and the collector of the transistor 9 to protect the transistor 9. When the battery 1 is reversely connected, the zener diode 20 and the resistor 27 are provided. , Diodes 15 and 16, transistor 9, diode 18 and
When a current flows through the transistor 19, the transistor 9 has an NPN junction and thus performs a current amplification action. As a result, the transistor 9 is burned due to the overcurrent. But,
By inserting the diode 17, the above current is bypassed and the overcurrent flowing to the transistor 9 is blocked.

Diodes 18 and 19 are connected to transistor 9
In the switching operation of 1, the counter electromotive voltage generated at both ends of the exciting coil 7 is circulated, the generation of high voltage is suppressed, the destruction of the transistor 9 is prevented, and at the same time, the circulating current is passed through the exciting coil 7 to It is a flywheel diode for ensuring the reciprocating movement of the plunger 120. Conventionally, a flywheel diode has been used for the above purpose. However, when the circulating current is too large, the suction holding force of the plunger 120 becomes strong and the reciprocating speed of the plunger 120 slows down. In (2), two (or more) diodes are inserted in series.

As a result, the total resistance of the diodes is increased and the circulating current is suppressed, so that the plunger 120
Since the electromagnetic force that holds is reduced and the return speed can be increased,
The operating stroke of the plunger 120 can be increased and the operating speed can be increased. Further, instead of inserting two diodes in series, one of them can be a resistor, and the same effect can be obtained.

The diode 13 is used for the following purposes. That is, the time constant of the first monostable multivibrator based on the IC10 is experimentally determined from the startability of the engine, and is usually set to 0.5 to 3 seconds. Also, I
The time constant of the astable multivibrator by C11 is determined by the mass of the plunger 120 and the spring force of the spring 121, etc., which make up the pump. Normally, the HI time is 10 to 20 ms and the LO time is 20 to 100 ms. Is set to.

In the case of the 555 type timer IC used in this embodiment, without the diode 13, the HI time is
HI = (0.693) x (resistance value of resistor 24 + resistor 25
Resistance value x x (capacitance of capacitor 33), and L
O time is determined by LO = (0.693) × (resistance value of resistor 25) × (capacitance of capacitor 33),
The above (HI time <LO time) cannot be set. Therefore, by inserting the diode 13 at both ends of the resistor 25 as shown in FIG. 1, the value of the resistor 25 in the HI time determining equation is apparently zero, which enables this. In order to achieve the above object without using the diode 13, it is possible to insert an inverting circuit composed of a transistor or the like on the output side. The resistor 24 is a first resistor and the resistor 25 is a second resistor.

During cranking when the engine is started (when the starter motor is rotating), the transistor igniter 5
Is turned on and off slowly, so at point A
(B) ignition pulse is generated as shown in t ₂ ~t _3. When the voltage at the point A is in the HI state, the transistor 9 repeats the switching operation in the same operation as when the ignition switch 2 is turned on, the exciting coil 7 repeats energization and non-energization, and the plunger 120 reciprocates to function as a pump. Fulfill. Next, when the voltage at the point A becomes LO, the electric charge accumulated in the capacitor 29 is discharged through the resistor 21, the transistor igniter 5 and the diode 12 and reset, so that the potential at the point A becomes HI again. The above operation is repeated every time.

When the engine rotates at high speed,
Although the number of times the transistor igniter 5 is turned on and off increases, the operation of the electromagnetic pump 6 is set to the same operation speed as during cranking due to the functions of the timer ICs 10 and 11.

Example 2. In the first embodiment, the configuration in which the HI-LO trigger signal is input from the ignition coil to start the operation of the electromagnetic pump is shown, but the second embodiment uses the negative voltage in the capacitor discharge ignition device (CDI circuit) as the trigger signal. Shows what is configured. The capacitor discharge ignition device (CDI circuit) is used as an ignition device for a relatively small engine.

FIG. 5 is a control circuit diagram of the electromagnetic pump of the second embodiment, and FIG. 6 is a timing chart. The same components as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted, and the description of the operation similar to that of the first embodiment will be omitted. In the figure, 50 is an alternator, which is a charge coil 50a and a sensor coil 50b.
have. 51 is a thyristor, 52 and 53 are diodes, 54 is a capacitor, 55 to 57 are resistors, and 58 is a Zener diode. The resistor 57 is a protective resistor for protecting the thyristor 51.

Turn on the ignition switch 3 (see FIG. 6).
T ₀ ), battery 1 to fuse 2, resistor 55,
Since a current flows through the Zener diode 58 and the capacitor 29 to the base of the transistor 8, the same operation as that of the first embodiment is performed.

Next, during cranking (from t _{2 in} FIG. 6, when the cell motor is rotating), an AC voltage is generated in the charge coil 50a of the AC generator 50, and the current half-wave rectified by the diode 52 is transferred to the capacitor 54. Will be charged. On the other hand, when a voltage is generated in the sensor coil 50b, a current flows to the gate of the thyristor 51 via the diode 53, so that the thyristor 51 is ignited and the electric charge of the capacitor 54 is discharged through the ignition coil 4, and this discharge current causes The ignition coil 4 obtains an ignition voltage.

As a result of this discharge, point C in FIG.
Since a negative voltage as shown in (b) is intermittently generated, the charge stored in the capacitor 29 is stored in the zener diode 58,
It discharges through the resistor 56, the ignition coil 4, and the diode 12. Therefore, the potential at the point B continuously becomes HI, and the above operation is repeated. Note that many electric components made up of various motors and inductors such as coils are installed in the vehicle, and an induced voltage may be generated in the electric circuit of the motor or coil when the circuit is opened or closed. This is to prevent the electric charge of the capacitor 29 from being discharged and the electromagnetic pump 6 to malfunction due to a low induced voltage which is lower than the voltage of the diode. According to the present invention, the electromagnetic pump 6 operates reliably only when the engine is operating, without causing a malfunction due to noise from other electrical components.

Example 3. In the first embodiment, two timer ICs are used.
In this example, one monostable multivibrator and the other is an astable multivibrator are shown. However, in addition to the two timer ICs described above, one more monostable multivibrator is added to the astable multivibrator. It may be configured to control the control voltage (CV) of the vibrator. Next, a third embodiment having this configuration will be described.

FIG. 7 is a control circuit diagram of the electromagnetic pump of the third embodiment, and FIG. 8 is its timing chart. The same components as those in the first embodiment will be designated by the same reference numerals and description thereof will be omitted, and description of the same operation as that of the first embodiment will be omitted. 38 is a third timer IC constituting a second monostable multivibrator, 39 is a Zener diode, 40 is a diode, 41 to 43 are resistors, and 44 to 48 are capacitors. At the time of turning on the ignition switch 3 and at the time of cranking, the operation is exactly the same as that of the first embodiment.

When the engine rotates (t4 in FIG. 8), the number of ignition pulses generated at the point A increases, so that the resistor 41 and the capacitor 45 are connected from the OUT terminal of the timer IC 38.
The pulse is continuously output with the time constant of (5 to 10 ms). This pulse passes through an integrating circuit (low-pass filter) consisting of a resistor 42 and a capacitor 47, and a DC voltage having a magnitude proportional to the input pulse density (that is, a voltage proportional to the rotation speed) is passed through the diode 40 to a timer. I
Input to CV terminal of C11.

The timer IC 11 outputs a pulse signal of HI or LO with a time constant consisting of the resistors 24 and 25, the capacitor 33 and the diode 13 as described in the first embodiment.
The time constant can be changed by changing the CV terminal voltage in proportion to the engine speed. When the engine speed increases and the number of ignition pulses per unit time increases, the CV terminal voltage increases, and the stability of HI of the OUT terminal output of the timer IC11 increases. As a result, the reciprocating motion of the plunger 120 becomes faster. As described above, according to the present invention, it is possible to feed the fuel in proportion to the engine speed.

Example 4. Example 4 describes a configuration in which the electromagnetic pump of the blocking oscillation circuit shown in FIG. 11 of the conventional example can be used in a capacitor discharge ignition device (CDI circuit). FIG. 9 is a control circuit diagram of the electromagnetic pump of the fourth embodiment. In the figure, the same components as those in the conventional example and the second embodiment are designated by the same reference numerals and the description thereof is omitted. 125 is a Zener diode, 12
6 is a triac element.

Next, the operation will be described. When the ignition switch 3 is turned on, a voltage is applied to the blocking oscillation circuit (including the transistor 107, the signal coil 108, and the exciting coil 109) through the triac element 126, the blocking oscillation circuit starts oscillation, and this oscillation causes the plunger 120 to move. Excitation coil 109 attracts, spring 12
1 returns and reciprocates plunger 120.

The turn-off of the triac element 126 is a resistance
Since 117 is not large enough to hold the holding current, it naturally turns off, and after the plunger 120 reciprocates several times, the blocking oscillator circuit stops oscillation. The rotation of the AC generator 50 charges and discharges the capacitor 54,
A current at the time of discharging is passed through the ignition coil 4 to obtain an ignition voltage. The signal at the time of this discharge is the Zener diode 12
The triac element 126 is made conductive via 5 and the blocking oscillation circuit is continuously oscillated, and the plunger 120 is reciprocated to perform a pumping action.

[0057]

Since the present invention is constructed as described above, it has the following effects.

The first aspect of the present invention uses the first monostable multivibrator circuit, which operates by using the pulse from the ignition coil as a trigger signal, operates the electromagnetic pump for a certain period of time when the ignition switch is on, and feeds fuel to the engine in advance. Therefore, the startability of the engine is improved. Further, the energization of the exciting coil is controlled by the output from the astable multivibrator circuit only during the operation of the first monostable multivibrator circuit, so that the electromagnetic pump is brought to an emergency stop when the vehicle rolls over or collides.

Further, a capacitor discharge ignition device (CDI) in which a signal pulse of negative potential is output from the ignition coil
In the circuit), since the Zener diode is provided between the ignition coil and the monostable multivibrator circuit, malfunction of the electromagnetic pump due to noise from other electric components is prevented.

Further, by changing the control voltage of the timer IC forming the astable multivibrator circuit in proportion to the engine speed, the operating speed of the electromagnetic pump is changed in accordance with the engine speed, and the fuel supply is changed. Can be sent.

By connecting a plurality of diodes in series in parallel with the exciting coil of the electromagnet section, the return operation of the plunger can be accelerated, the number of operations can be increased, and the fuel feeding amount can be increased.

Further, by connecting a plurality of diodes in series to the base of the switching element that controls the current flowing through the exciting coil, the switching operation of the switching element is ensured at high temperature.

By connecting a diode between a plurality of diodes connected in series to the base of the switching element and the collector of the transistor, the switching element prevents burnout due to overcurrent when the battery is reversely connected. be able to

Further, the DC terminal, the TH terminal and the TR of the timer IC constituting the astable multivibrator circuit are
By connecting a diode between the 1G terminals in parallel with the resistor that constitutes the above-mentioned astable multivibrator circuit, the on / off time ratio required by the electromagnetic pump is eliminated without providing an inverting circuit constituted by a transistor or the like. Can be easily set.

The triac element is used to activate the blocking oscillation circuit, so that the electromagnetic pump can be operated by a signal pulse of negative potential from the ignition coil of the capacitor discharge ignition device (CDI circuit), and the zener diode is used as the vehicle. This prevents the electromagnetic pump from malfunctioning due to noise from other electrical components.

By constructing the coil of the electromagnetic pump so that a signal coil is not required, a compact, lightweight and inexpensive electromagnetic pump can be obtained.

[Brief description of drawings]

FIG. 1 is a control circuit diagram of an electromagnetic pump according to a first embodiment of the present invention.

FIG. 2 is a sectional view of an electromagnetic pump of the present invention.

FIG. 3 is a time chart of the control circuit according to the first embodiment of the present invention.

4 is a block diagram of the control circuit of FIG. 1. FIG.

FIG. 5 is a control circuit diagram of an electromagnetic pump that is Embodiment 2 of the present invention.

FIG. 6 is a time chart of the control circuit according to the second embodiment of the present invention.

FIG. 7 is a control circuit diagram of an electromagnetic pump according to a third embodiment of the present invention.

FIG. 8 is a time chart of Example 3 of the present invention.

FIG. 9 is a control circuit diagram of an electromagnetic pump according to a fourth embodiment of the present invention.

FIG. 10 is a circuit diagram showing a control circuit configuration of a conventional electromagnetic pump.

FIG. 11 is a sectional view showing a configuration of a conventional electromagnetic pump.

[Explanation of symbols]

1 Battery, 4 Ignition coil 5 Transistor igniter, 6,106 Electromagnetic pump 7 Excitation coil, 8, 9 Transistor 10 Timer IC that constitutes the first monostable multivibrator 11 Timer IC that constitutes the astable multivibrator 38 Second Timer IC that constitutes a monostable multivibrator 13,18,19 Diode 39,58,125 Zener diode, 50 Alternator 120 Plunger, 121 Spring, 126 Triac element

Claims (9)

[Claims] 1. A control circuit of an electromagnetic pump for fuel supply of an engine having an ignition coil, the electromagnetic pump having an exciting coil and a plunger driven by the exciting coil, the suction of the exciting coil. And reciprocating the plunger to suck and discharge fluid, and each time the ignition coil is connected to the ignition coil and a voltage is applied to the ignition coil, a first pulse having a predetermined time width is applied. A first monostable multivibrator circuit for generating a signal once, and a period of time shorter than the time width of the first pulse signal while receiving the first pulse signal and outputting the first pulse signal. An astable multivibrator circuit that repeatedly outputs a second pulse signal with a pulse generator, and excites the exciting coil with the second pulse signal. A control circuit for an electromagnetic pump, comprising: 2. The ignition coil is connected to a capacitor discharge igniter (CDI circuit), and a zener diode is inserted in series from the ignition coil to a signal line connected to the first monostable multivibrator. The control circuit for an electromagnetic pump according to claim 1, wherein: 3. The astable multivibrator circuit comprises a time constant circuit which comprises a resistor and a capacitor for determining a time width of the second pulse signal, and a second pulse signal which depends on a signal level applied from the outside. A second monostable multivibrator circuit, which is composed of a second timer IC whose period is adjustable, and which is connected to an ignition coil and converts a signal pulse of the ignition coil into a third pulse having a constant time width. And a low-pass filter circuit for averaging the third pulse output to obtain a speed signal corresponding to the rotation speed of the engine. The speed signal is applied to the second timer IC, and the astable multivibrator is provided. 3. A means for causing the cycle of the second pulse signal output of the circuit to change in response to the engine speed. Is a control circuit for an electromagnetic pump according to any one of 2. 4. The control circuit for an electromagnetic pump according to claim 1, wherein a plurality of diodes connected in series are connected in parallel with the exciting coil. 5. A plurality of diodes are connected in series between a base terminal of the switching element and an astable multivibrator that supplies a signal to the switching element, and the plurality of diodes are inserted in series. 6. A control circuit for an electromagnetic pump according to claim 1. 6. An anode of a diode whose cathode is connected to the base terminal among a plurality of diodes connected between the base terminal of the switching element and the astable multivibrator circuit, or the astable The control circuit for an electromagnetic pump according to claim 5, wherein a diode is connected between a connection point of the diode close to the multivibrator circuit and a collector terminal of the switching element. 7. The astable multivibrator circuit comprises a time constant circuit, which comprises a resistor and a capacitor, for determining a time width of the second pulse signal, and the second pulse signal according to a signal level applied from the outside. And a second timer IC whose period can be adjusted, and the resistor is configured by serially connecting a first resistor and a second resistor in which a diode is connected in parallel. The control circuit for an electromagnetic pump according to any one of claims 1 to 6, wherein: 8. An exciting coil having two coils, a signal coil and an exciting coil which are magnetically coupled to each other, and a transistor having a base terminal and an emitter terminal connected to both ends of the signal coil. In the control circuit of the electromagnetic pump configured to output a blocking oscillation circuit, is connected between the base terminal of the transistor and the power supply, and a triac element in which a limiting resistor that limits the on-current to the holding current or less is connected in series. A control circuit for an electromagnetic pump, comprising: a zener diode connected between the gate of the triac element and an ignition coil. 9. An electromagnetic pump having one coil having no electromagnetic coupling with other coils, wherein the electromagnetic pump has one coil.
An electromagnetic pump comprising the control circuit according to any one of 1.