JPS6056269B2 - magneto igniter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electronic ignition device for a non-contact type magneto, and particularly to one that controls the ignition timing according to the rotation of an engine.

Conventionally, various types of engine ignition systems generate ignition voltage on the secondary side of the ignition coil by opening and closing a semiconductor switching element such as a thyristor or transistor in response to an ignition signal generated at the ignition timing of the engine. The ignition timing is automatically determined by the ignition signal waveform generated in synchronization with the rotation of the engine.

In other words, it was possible to meet the requirements for advancing the angle to prevent sagging in the low speed range, but if a retardation characteristic was required to maintain engine horsepower in the medium to high speed range, it would be possible to meet the requirements. The drawback was that it could not meet the demands. The present invention provides a magneto ignition device that eliminates the above-mentioned drawbacks and provides highly accurate ignition timing characteristics from medium to high speeds as described below. below,
An embodiment of the present invention shown in the drawings will be described.

In the embodiment shown in FIGS. 1 to 6, reference numeral 1 denotes a power generating coil of a magneto (not shown), which is a power supply device, and generates positive and negative alternating current voltages in synchronization with the rotation of the engine. 2, 3
4 is a diode that rectifies the output of this generating coil; 4 is a capacitor charged by the output of the generating coil 1 rectified by this diode 2; 5 is an ignition coil connected to the discharge circuit of this capacitor; It consists of a primary coil 5a connected in series with a secondary coil 5b connected to a spark plug 6.

A thyristor 7 is a switching element provided in the discharge circuit of the capacitor 4, and when the thyristor 7 is conductive, the charge of the capacitor 4 is discharged to the primary coil.

Reference numeral 8 denotes a signal coil for generating a gated ignition signal, which is an angular position detecting device, which is synchronized with the rotation of the engine and receives a first angular signal a of one polarity corresponding to a predetermined crank position of the engine and this first ignition signal. A second angle signal b of the other polarity and having a wider angular width corresponding to a crank position delayed by θ degrees than the position where the angle signal is generated is generated.

9, 10, 11, 17 are diodes for blocking backflow, 12
, 13 is a resistor connected to the gate of the thyristor 7,
14 is a transistor connected to ground the second angle signal b, and 15 is an ignition timing which starts calculation based on the first angle signal a and calculates ignition timing according to the operating state of the engine. The output of the arithmetic circuit is connected to the base of the transistor 14 via a resistor 16.

The resistor 16 and the transistor 14 constitute a circuit for controlling the bypass of the second angle signal b of the other polarity of the signal coil 8. Details of this circuit 15 are shown in FIG. Next, in FIG. 2, FIG. 2 shows the mechanical parts of the first and second angular position detecting devices, and 18 is a flywheel of a magnet generator, which has a cylindrical shape.

20 are four permanent magnets fixed to the inner peripheral surface of the magnet.
The permanent magnets 20 are adjacent to each other and have different polarities.

Reference numeral 19 denotes a stator core that is disposed opposite the permanent magnet 20 in the radial direction with a small distance therebetween, and around which the signal coil 8 is wound. The signal voltage A shown in FIG.
generate b.

Next, in FIG. 3, FIG. 3 shows a detailed circuit of the ignition timing calculation circuit 15, and 22 in the figure is a waveform shaping circuit for shaping the a signal output of the signal coil 8, 221, 222,
223, 228 resistors, 224 a voltage comparator (hereinafter referred to as a comparator), 225, 227 a capacitor, 226
is Daioh. 23 is a flip-flop circuit; 24 is an arithmetic circuit connected to this flip-flop circuit and generates a predetermined output according to the engine speed; 241, 242, 2;
43, 246, 247 are resistors, 244, 245 are diodes, 240 are capacitors, 248 are operational amplifiers (hereinafter referred to as operational amplifiers), 249 are voltage comparators (hereinafter referred to as comparators), 25 is the signal coil 8 Output signal a
The rotation speed-voltage conversion circuit (hereinafter referred to as F-V
(referred to as a circuit). The above flip-flop circuit 23
One input terminal S is connected to the waveform shaping circuit 22, and the other input terminal R is connected to the output of the comparator 249.

One output terminal Q of the flip-flop circuit 23 is connected to the resistor 2
42 to the inverting input terminal (hereinafter referred to as the (-) terminal) of the operational amplifier 248. The non-inverting input terminal of the operational amplifier 248 (hereinafter referred to as the ten-coin) is connected to the F-V circuit 25 via the resistor 241 and the diode 244.
(connected to the output terminal of) and resistors 246 and 24
It is biased by dividing the voltage of a power supply (not shown) at 7.

The output terminal of the operational amplifier 248 is the comparator 249
The capacitor 240 is connected to the ←→ terminal of
is connected to its own ←→ terminal via. The non-inverting input terminal 0→ of the comparator 249 is grounded.

FIG. 4 shows the output characteristics of the F-V circuit 25.
250 is an example of the characteristic, and the figure shows a case where the characteristic changes linearly.

Moreover, as shown in FIG. 4, this characteristic is such that the voltage Vrl at the rotation speed N1 is set equal to the bias voltage of the operational amplifier 248, and the (+) terminal voltage of the operational amplifier 248 is as shown in characteristic 251. Change. Next, in FIG. 5, time lines b-j indicate time charts of voltages A-H at various points in FIG. , M indicates a position slightly advanced from the maximum advanced angle position required by the engine, and generates the first angle signal.

S indicates the generation position of the second angle signal, and T indicates the top dead center. Next, the operation of the above embodiment will be explained. First, in the case of the CDI type magneto ignition system shown in FIG. The cycler 7 is made conductive at the time of output generation of the ignition timing calculation circuit 15 which inputs a, or the time of generation of the output voltage b of the signal coil 8, and the voltage is applied to the primary coil 5a of the ignition coil 5, and the voltage is applied to the secondary coil. This generates a high voltage to send a spark to the spark plug 6.

Next, the means for adjusting the conduction timing of the thyristor 7, that is, the ignition timing, will be explained in detail, including the advance angle characteristic diagram in FIG. 6.

Now, the engine is rotating at a constant speed higher than N1 and lower than NO as shown in Fig. 6, and the ignition advance angle in this case is not zero but at a position advanced by angle α from position T. Then, the operations shown in FIGS. 1 and 3 are as follows.

First, the F--circuit 25 counts or integrates the output voltage corresponding to the engine speed, and the output voltage 250 is higher than the bias voltage Vrl.

This output voltage 250 becomes the input voltage of the operational amplifier 248, and the positive terminal voltage 251 of the operational amplifier 248 changes with rotation as shown in the characteristics shown in FIG. On the other hand, the flip-flop circuit 23 is reset by the rise of the output voltage C to a high level at the position M, and the output voltage E
becomes high level.

When the output voltage E reaches a high level, the capacitor 20 charged with the voltage polarity shown in FIG.
Starts discharging at 2. As can be seen from the above equation, the magnitude of this discharge current 12 depends on the (+) terminal voltage 251 of the operational amplifier 248 if the resistance value of the resistor 242 is constant, and in this region, the output of the F-V circuit 25 It will depend on the voltage 250.

That is, as the engine speed increases, the discharge current 12 becomes smaller, the slope of its characteristics becomes gentler, and the angular width of the high-level output voltage E of the flip-flop 23 becomes wider. High level output voltage E obtained as above
In other words, it corresponds to the calculation result of the calculation circuit 24. Next, as the capacitor 240 starts discharging, the output voltage D of the operational amplifier 248 drops as shown in FIG. 5, and when it reaches zero voltage, a positive pulse voltage is generated at the output of the comparator 249. becomes the reset input.

The flip-flop circuit 23 is reset when the reset pulse is input to its input terminal R, and its output voltage E becomes low level. Next, as described above, when the output voltage E of the flip-flop circuit 23 becomes low level, the capacitor 240 shown in FIG. 3 starts to be charged with the current 11 shown in the following equation in the direction of the polarity shown.

As can be seen from the above equation, the magnitude of this charging current 11 is the same as that of the operational amplifier 2 if the resistance values of the resistors 243 and 242 are constant.
48 (+) terminal voltage 251.

That is, in this region, the output voltage 25 of the F-V circuit 23
0, the charging current 11 increases as the rotational speed increases, and the slope of its current characteristics becomes steeper.

As described above, in this region, as the rotational speed increases, the angular width of the high-level output voltage E of the flip-flop 23 becomes wider. Here, the output voltage E of the arithmetic circuit 15 obtained by the above operation is supplied to the base of the transistor 14 via the resistor 16 as shown in FIG. If b is connected as a bypass to the ground side, A in Fig. 5
From the positional relationship between the H signal and the F signal, the gate signal of the thyristor 7 has the G waveform shown in FIG.

That is, the engine speed is N.

I: d. In the rotation range between N1 and N1, as the rotation speed increases, the fall timing of the high-level output voltage E of the flip-flop 23 is delayed, so the conduction timing of the thyristor 7 is delayed, and the ignition timing is eventually determined by the engine rotation. As the number increases, it will be delayed. And the engine speed is N. When the rotation is reached, the output voltage 250 of the F-■ circuit 25 and the 0→terminal voltage 251 of the operational amplifier 248 become constant, so
The fall timing of the high-level output voltage E of the flip-flop 23 remains constant regardless of the increase in engine speed, and therefore the ignition timing of the engine also remains constant. Next, when the output voltage B becomes high level again at position M in the range of rotational speeds lower than N1 and higher than N2 shown in FIG. 6, the flip-flop circuit 23 is set and the capacitor 240 is discharged as described above.

At this time, as can be seen from FIG. 4, the output voltage 250 of the F-V circuit 25 is lower than the bias voltage Vr.
The output voltage 250 of the F-V circuit 25 does not contribute to the discharge current I2. is shown in the formula below. As can be seen from the above equation, in this region, the magnitude of the discharge current I is constant regardless of the rotation speed.

Further, the charging current I is also constant regardless of the rotation speed.

As described above, in this region, the angular width of the high-level output voltage king of the flip-flop circuit 23 is a constant value regardless of the rotation speed. Therefore, the conduction timing of the transistor 4 and the thyristor 7 is constant regardless of the engine speed, and the ignition timing of the engine is also constant. Next, the rotation speed N shown in FIG. In the region lower than , the capacitor 2 due to the output voltage a of the signal coil 8
40 discharge current I. , charging current I, are constant values as described above, and the angular width of the high-level output voltage E of the flip-flop circuit 23 is a constant value regardless of the rotation speed. on the other hand,
As shown in FIG. 5g, the output voltage b of the signal coil 8 is small because the rotational speed is low.

Therefore, even if the transistor 14 is bypassed by the output E of the arithmetic circuit 5, when the bypass is completed (when the output voltage E falls), the voltage at the point G becomes the conduction voltage V of the cycler 7.
Therefore, the calculation result of the calculation circuit 15 does not contribute to ignition, and the output voltage b of the signal coil 8 is the conduction voltage V of the cycler 7.

When the temperature reaches 1, the thyristor 7 becomes conductive and the engine is ignited. Therefore, in such a low rotation range, the cyclist 7 is controlled only by the output b of the signal coil 8 having a wide angular width 3.
Since the lead angle contributes to conduction, an advance angle characteristic as shown at 26 in FIG. 6 can be obtained.

This is because the signal with a wide angular width grows as the rotation increases. 4: With the above-described operation, the lead angle characteristic shown by the solid line 27 in FIG. 6 is obtained.

That is, when the rotational speed is below N, the angle advances as the output waveform E of the output voltage b of the signal coil 8 grows. In the above, the output waveform F of the output voltage b of the signal coil 8 below the threshold level Vc is bypassed for the entire high level period by the high level of the output signal E obtained from the above calculation result. The ignition timing is the pulse fall timing of the output signal E obtained by the calculation result of the calculation circuit 15, that is, the position where it changes from high level to low level. As described above, in the rotation range where precision of ignition timing is required due to horse power or the like with respect to medium to high speeds of the engine, the present invention provides a method for determining the first angle signal from the generation position of the first angle signal. The ignition timing is determined by an ignition timing calculation circuit that calculates and outputs the signal width up to the crank position, which is determined as a function of the occurrence position and occurrence period of the engine. Then, the ignition timing is determined by utilizing the growth of the signal waveform accompanying the increase in rotation of the second angle signal corresponding to the crank position delayed by a predetermined angle from the generation position of the first angle signal. Because it is
Since highly accurate ignition timing characteristics can be obtained even from medium to high engine speeds, an ignition device having good ignition timing characteristics from low to high engine speeds can be provided.

Moreover, since the first and second angle signals are generated by one angular position detection device, there is an advantage that the configuration is simple.

[Brief explanation of the drawing]

FIG. 1 is an electric circuit diagram showing one embodiment of the present invention, and FIG.
1 is a front view showing the structure of the angular position detection level device according to the embodiment shown in FIG. 1, FIG. 3 is an electric circuit diagram showing further details of the embodiment shown in FIG. FIG. 5 is an operation waveform diagram illustrating the operation of the embodiment of FIG. 1. FIG. 6 is a lead angle characteristic diagram of the embodiment of FIG. 1. In the figure, 1 is a power generation coil, 5 is an ignition coil, 6 is a spark plug, 7 is a thyristor, 8 is a signal coil, 14 is a transistor, 15 is an ignition timing calculation circuit, 22 is a waveform shaping circuit,
23 is a flip-flop circuit, 24 is an arithmetic circuit, 25 is an F-V circuit, and 30 is a control circuit.

Claims (1)

[Claims] 1. A power supply device that can generate positive and negative outputs in synchronization with the rotation of the engine and energize the ignition coil with the rectified output, a switching element that controls the energization of the ignition coil, and A first angle signal of one polarity corresponding to a predetermined crank position and a second angle signal of the other polarity corresponding to a crank position delayed by a predetermined angle from the generation position of the first angle signal and directly supplied to the switching element. one angular position detection device that generates an angular signal, which is determined from the generation position of the first angular signal as a function of the generation position of the first angular signal and the generation period of the first angular signal. A magneto ignition device comprising: an ignition timing calculation circuit that calculates and outputs a signal width up to the crank position; and a control circuit that bypasses the second angle signal using a signal obtained by the calculation result of the ignition timing calculation circuit. .