JPS6410664B2 - - Google Patents

Description

[Detailed Description of the Invention] Conventionally, a magnet generator exciter coil driven in synchronization with the engine is provided, a capacitor is charged by the positive direction voltage of this exciter coil, and a thyristor is turned on by the negative direction voltage of the exciter coil. This is a so-called capacitor discharge type non-contact ignition device that rapidly discharges the charge stored in the capacitor to the primary coil of the ignition coil, induces a high voltage in the secondary coil of the ignition coil, and ignites the engine. is well known.

In this type of non-contact ignition device, as a means for preventing engine overspeed, there is a method of temporarily stopping engine ignition when the engine rotation speed increases to a predetermined rotation speed before the overspeed state occurs; Various methods have been proposed to rapidly retard the ignition angle of the engine, but the former method has the advantage of being simple and inexpensive, but since it temporarily stops the engine ignition, it is harmful to the human body. The latter method has the serious disadvantage of emitting unburned gas, which is harmful to the human body, but has the disadvantage of an extremely complicated structure and high manufacturing costs.

The present invention has been made focusing on the above points,
The purpose of this is to wrap a signal coil around the same stator core around which an exciter coil is wound around a magnet generator that is driven in synchronization with the engine, thereby preventing the engine from reaching an overspeed state. To provide an excellent non-contact ignition device with a simple structure and low manufacturing cost, capable of preventing engine overspeed by rapidly retarding the ignition angle of the engine when the engine speed increases to a predetermined rotation speed. be.

The embodiment of the present invention shown in FIG. 1 will be described below. In this figure, G is a magnet generator driven in synchronization with the engine, and this magnet generator G includes a magnet rotor M, a stator core B provided opposite to the rotor M, and the core B It consists of an exciter coil E and a signal coil A that are wound around the coil. The signal coil A is divided into a first signal coil A ₁ and a second signal coil A ₂ by providing an intermediate terminal T as shown in the figure. next,
K is a semiconductor circuit section, and this semiconductor circuit section K consists of thyristors _S1 , _S2 , _S3 , capacitors _C1 , _C2 , diodes _D1 to _D7 , and resistors _R1 to _R4 , respectively. Connected as shown. Next, I is an ignition coil, and this ignition coil I is made up of a primary coil _W1 connected to the semiconductor circuit section K, and a secondary coil _W2 connected to the spark plug P of the engine.

In one embodiment of the present invention configured as described above, first, when the engine is rotated manually or by other methods, the magnet rotor M rotates in synchronization with the engine, and the exciter coil wound around the stator core B rotates. The positive direction voltage VE ₁ and the negative direction voltage are shown by the arrows in E.
VE ₂ is generated alternately, and positive direction voltages VA _1-1 and VA _2-1 and negative direction voltage VA _1-2 are also generated in the first and second signal coils A ₁ and A ₂ as shown by arrows in the figure. ，
VA _2-2 occurs alternately. Then, the positive and negative voltages VE ₁ generated in the exciter coil E,
The waveform of VE ₂ is shown in Figure 2 A, and the waveform of the first signal coil A ₁
The waveforms of the positive and negative direction voltages VA _1-1 and VA _1-2 generated in the signal coil A ₂ in FIG _. 2 are shown in _FIG. The waveforms of ₂ are shown by dashed lines in FIG. 2C, respectively.

Thus, the positive voltage _VE1 generated in the exciter coil E charges the capacitor _C1 to the polarity shown in FIG. ₁ via the diode D2. and,
The waveform of the charging voltage VC ₁ of the capacitor C ₁ is shown by the solid line in FIG. 2A. On the other hand, the positive direction voltage VA _2-1 generated in the second signal coil A ₂ is a diode
The waveform of the charging _voltage VC ₂ of the capacitor C ₂ becomes as shown by the solid line in Fig. _2C , which is connected to the gate of the thyristor S ₂ via the resistor R ₃ . At the rotation angle θ ₁ at which the gate trigger voltage Vg ₂ of the thyristor S ₂ is reached, the thyristor S ₂ is turned on, and thereby the thyristor S ₃ is also turned on. The ON state of these thyristors S ₂ and S ₃ is the capacitor C ₂
continues until the rotation angle θ ₂ at which the charging voltage VC ₂ of the thyristor S ₂ becomes lower than the gate trigger voltage Vg ₂ of the thyristor S ₂ as shown in FIG. During normal rotation before over-speeding, the first and second signal coils A ₁ and A ₂
It is set to be before the rotation angle θ ₃ at which the next negative direction voltages VA _1-2 and VA _2-2 occur.

Therefore, when the negative direction voltage VA _1-2 is generated in the first signal coil A ₁ next, since the thyristor S ₃ is in the OFF state as described above, the thyristor _{S 1} , and its negative direction voltage VA _1-2 is applied to the gate of
At the rotation angle θ ₄ at which the gate trigger voltage Vg ₁ of the thyristor S ₁ is reached, the thyristor S ₁ is turned on, and as a result, the charging voltage VC ₁ of the capacitor C ₁ becomes the rotation angle θ ₄ as shown in FIG. is rapidly discharged to the primary coil W ₁ of the ignition coil I via the thyristor S ₁ at
A high voltage is induced in the secondary coil _W2 , which causes a high voltage spark to fly to the engine's spark plug P, igniting the engine.

By repeating the above operations, the engine has a rotation angle of θ ₄
It is ignited and rotates on its own. In addition, in this case, the negative direction voltage generated in the exciter coil E
VE ₂ is bypassed into the circuit of resistor R ₁ and diode D ₁ , and the primary coil W ₁ of ignition coil I and resistor
Since it is applied to the gate of thyristor S ₂ via R ₂ , the gate applied voltage VE ₂ becomes a low voltage as shown by the solid line in Fig. 2A, and at a rotation angle θ ₅ the thyristor
The gate trigger voltage Vg ₁ of S ₁ is reached and the thyristor S ₁ is turned on, but since the capacitor C ₁ has already been discharged at this time, the engine does not ignite at this rotation angle θ ₅ .

Next, when the rotational speed of the engine increases to a predetermined rotational speed before the overspeeding state occurs, the positive voltage VA _2-1 of the second signal coil A ₂ causes the diode
Charging voltage of capacitor C ₂ charged via D ₆
V'C ₂ changes as shown by the broken line in Figure 2C.
That is, since the positive direction voltage VA _2-1 of the second signal coil A ₂ increases as the rotation speed increases, the charging voltage of the capacitor C ₂ also changes from VC ₂ shown by the solid line to V'C ₂ shown by the broken line. As a result, the rotation angle at which the aforementioned thyristors S ₂ and S ₃ are shifted from the on state to the off state changes from θ ₂ to θ ₃ .

Therefore, since the negative voltage VA _1-2 of the first signal coil A ₁ is generated when the thyristor S ₃ is in the on state, this negative voltage VA _1-2 is short-circuited by the thyristor S ₃ . , no voltage is applied to the gate of thyristor S ₁ at all, and as a result, thyristor S ₁ was previously turned on at rotation angle θ ₄ to ignite the engine, but now the negative voltage of exciter coil E shown in Figure 2 At the rotation angle θ ₅ when the thyristor S ₁ is turned on by the reduced voltage V′E ₂ of the directional voltage VE ₂ , the charging voltage of the capacitor C ₁ is discharged as shown by the broken line V′C ₁ ,
The engine will start to ignite. Therefore, the ignition angle of the engine is rapidly retarded from the rotation angle θ ₄ to θ ₅ , thereby making it possible to prevent the engine from over-speeding.

As is clear from the above description, the present invention includes a magnet generator driven in synchronization with an engine, an exciter coil and a signal coil wound around the same fixed core provided in the magnet generator, and the exciter coil and the signal coil. A capacitor connected to the exciter coil via a diode so as to be charged with the positive voltage generated in the ignition coil, a primary coil connected to this capacitor via a thyristor, and a secondary coil of this ignition coil. In a non-contact ignition device for an engine, the thyristor is turned on by applying a negative voltage of the signal coil to the gate of the thyristor during normal rotation of the engine. In addition to providing a circuit, the negative direction voltage of the signal coil is short-circuited via the semiconductor switching element at a predetermined rotation time before the engine rotation speed becomes an overspeed state, and the negative direction voltage of the exciter coil is connected to the thyristor. By installing a semiconductor circuit that turns on the thyristor by applying a voltage to the gate of the engine, when the load of the engine suddenly decreases, the rotational speed increases and the thyristor is turned on. When the predetermined rotational speed is reached, the ignition accuracy of the engine is significantly retarded compared to the conventional one, thereby reliably preventing the engine from becoming overspeeded. Since the above-mentioned semiconductor circuit especially provided according to the present invention has an extremely simple structure, it is possible not only to downsize the entire device but also to reduce the manufacturing cost.

[Brief explanation of the drawing]

FIG. 1 is an electrical wiring diagram showing a non-contact ignition device according to an embodiment of the present invention, and FIG. 2 A, B, and C are voltage waveform diagrams for explaining the operation of the device. In the figure, G is a magnet generator, M is a magnet rotor, B is a stator core, E is an exciter coil, A is a signal coil, A ₁ is a first signal coil, A ₂ is a second signal coil, K is a semiconductor circuit section, S ₁ , S ₂ , S ₃ are thyristors, C ₁ , C ₂ are capacitors, D ₁ to D ₇ are diodes, R ₁ to _{R 4} are resistors, I is an ignition coil, and W ₁ is a primary coil. , W ₂ is the secondary coil, P is the spark plug.

Claims (1)

[Claims] 1 A magnet generator driven in synchronization with the engine, an exciter coil and a signal coil wound around the same fixed core provided in this magnet generator, and a generator configured to be charged by the positive voltage generated in the exciter coil. An engine comprising: a capacitor connected to the exciter coil via a diode; an ignition coil having a primary coil connected to the capacitor via a thyristor; and an engine spark plug connected to a secondary coil of the ignition coil. In the non-contact ignition device, a semiconductor circuit is provided that applies a negative voltage of the signal coil to the gate of the thyristor to turn on the thyristor during normal rotation of the engine, and
At a predetermined rotation speed before the rotational speed of the engine reaches an overspeed state, the negative direction voltage of the signal coil is short-circuited via a semiconductor switching element, and the negative direction voltage of the exciter coil is applied to the gate of the thyristor. 1. A non-contact ignition device for an engine, comprising a semiconductor circuit configured to turn on the thyristor.