JPS6149503B2 - - Google Patents

Description

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

Conventionally, this type of engine ignition system generates an 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, we were able to meet the demand for advance angle speeds 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, we would not be able to meet the requirements. The drawback was that it was not possible to respond to

The present invention solves the above-mentioned drawbacks and provides an engine ignition system that can provide highly accurate ignition timing characteristics from medium to high speeds as described below.

Embodiments of the present invention will be described below with reference to the drawings. First, in FIGS. 1 and 2 showing the CDI ignition system, 1 is a magneto, 101 is a bowl-shaped flywheel that is rotationally driven by the engine, and 102 is a bowl-shaped flywheel that is rotatably driven by the engine. None, 4 permanent magnets adjacent and fixed, 10
3, 104 are first and second stator cores installed at equal angular positions inside the flywheel 101;
5 is an I-shaped third stator core 104 installed inside the flywheel 101 with a θ angle shift of θ angle.
The stator core 106 is a magneto power generation coil, which is wound around the first stator core 103 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 106, 4 is a capacitor charged by the rectified output of this diode 2, and 5 is this capacitor 4.
The ignition coil is connected to a discharge circuit, and is composed of a primary coil 5a connected in series with the capacitor 4 and a secondary coil 5b connected to the ignition 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 5a. Reference numeral 8 denotes a signal coil for generating an ignition signal, which is a first angular position detecting device, and is wound around the third stator core 105 and detects a predetermined crank position of the engine (maximum advance position required by the engine) in synchronization with the rotation of the engine. Positive and negative alternating current voltages are generated at a position advanced by a predetermined distance, and one of the positive and negative voltages becomes the first angle signal a. Reference numeral 10 denotes a signal coil for generating an ignition signal, which is a second angular position detection device, and the generator coil 1 is connected to the second stator core 104.
It is wound with a smaller number of turns than 06, and generates a positive and negative AC voltage with a wide angular width at a crank position that is delayed by θ angle from the generation position of the first angle signal a in synchronization with the rotation of the engine, One of the positive and negative signals becomes the second angle signal b, and the other becomes the charging pressure c of the capacitor 4. Moreover, the positive and negative AC voltages generated in the signal coil 10 are in phase with that of the power generation coil 106. 9, 11, 17, 18, and 19 are rectifying diodes, 12 and 13 are resistors connected to the gate of the thyristor 7, and 14 is connected to bypass the second angle signal b to ground. Transistor 15 is an ignition timing calculation circuit which starts calculation upon receiving the first angle signal a and calculates the ignition timing according to the operating state of the engine, the output of which is connected to the base of the transistor 14 via resistor 16. has been done. The above resistor 16 and transistor 14
A control circuit 30 for bypassing the second angle signal b of the signal coil 10 is constructed by the above.

Next, FIG. 3 shows a detailed circuit of the ignition timing calculation circuit 15, and 22 in the figure shows the signal coil 8.
This is a waveform shaping circuit that shapes the waveform of the first angle signal a, and includes resistors 221, 222, 223, and 228, a voltage comparator (hereinafter referred to as a comparator) 224, capacitors 225, 227, and a diode 226. 23 is a flip-flop circuit; 24 is an arithmetic circuit that is connected to this flip-flop circuit 23 and generates a predetermined output according to the engine speed;
It consists of diodes 244 and 245, a capacitor 240, an operational amplifier (hereinafter referred to as an operational amplifier) 248, and a voltage comparator (hereinafter referred to as a comparator) 249. Reference numeral 25 denotes a rotation speed-voltage conversion circuit (hereinafter referred to as an F-V circuit) which captures the output voltage of the flip-flop circuit 23 as a rotation speed signal and converts it into a DC voltage proportional to the number of rotations.

One input terminal S of the flip-flop circuit 23 is connected to the waveform shaping circuit 22, and the other input terminal R is connected to the output of the comparator 249. In addition, the flip-flop circuit 23
One output terminal Q of is connected to resistor 242 and diode 2
45 and a resistor 243 in series to an inverting input terminal (hereinafter referred to as the (-) terminal) of the operational amplifier 248.

The non-inverting input terminal (hereinafter referred to as (+) terminal) of the operational amplifier 248 has a resistor 241 and a diode 2.
44 to the output terminal of the F-V circuit 25,
It is connected to the voltage dividing point of resistors 246 and 247.
The output terminal of the operational amplifier 248 is connected to the (-) terminal of the comparator 249, and the capacitor 24
0 is connected to the (-) terminal and output terminal of the operational amplifier 248. A non-inverting input terminal (+) of comparator 249 is grounded.

FIG. 4 shows the output characteristics of the F-V circuit 25. Reference numeral 250 is an example of the characteristics, and the figure shows a case where the output characteristics vary linearly depending on the rotational speed. Further, as shown in FIG. 4, this characteristic 250 is set to be equal to the voltage Vr ₁ at the rotation speed N1 or the bias voltage of the (+) terminal of the operational amplifier 248. The input voltage changes as shown in characteristic 251.

Next, FIG. 5 shows output waveforms at each point A to H of the circuit shown in FIG. 3, with the horizontal axis representing time and the vertical axis representing voltage. a indicates the crank angle position of the engine, M indicates a position slightly advanced from the maximum advanced angle position required by the engine, and the first angle signal a is generated. S indicates a position delayed by θ angle from the M position, and a second angle signal b is generated. T indicates the top dead center of the engine.

Next, the operation of the embodiment will be explained.

First, in the case of the CDI type magneto ignition system shown in FIG. The thyristor 7 is made conductive at the time of output generation of the ignition timing calculation circuit 15 which receives as input or the time of generation of the second angle signal b of the signal coil 10, and the charge of the capacitor 4 is applied to the primary coil 5a of the ignition coil 5. , which generates a high voltage in the secondary coil 5b, causing a spark to fly to the spark plug 6.

By the way, as the engine speed increases, the output voltage of the generator coil 106 becomes delayed in phase due to the armature reaction, and decreases to the point where it becomes impossible to charge the capacitor 4 to a sufficient value.
Because the number of turns is small, a large voltage (larger than the rising voltage of the generator coil 106) proportional to the increase in rotational speed is generated without being affected by armature reaction, and within this voltage, the voltage in the c direction is generated. voltage will charge the capacitor 4, and the signal coil 10 will therefore compensate the generator coil 106.

Now, FIG.
This will be explained in detail with reference to the drawings.

For convenience of explanation, the engine now has the rotational speed shown in Figure 6.
If it is rotating at a constant speed with a rotation speed higher than N ₁ and lower than N ₀ , and the ignition advance angle in that case is not zero but a position advanced by angle α from the T position, the operation is as follows. Become.

First, the F-V circuit 25 counts or integrates the output voltage corresponding to the engine speed, and the output voltage 250 is higher than the bias voltage V _r1 . This output voltage 250 becomes the input voltage of the operational amplifier 248, and the (+) terminal voltage 251 of the operational amplifier 248 changes linearly in proportion to the rotational speed as shown in the characteristic 251 in FIG.

Further, the first angle signal a generated in the signal coil 8 varies depending on the rotation speed as shown in FIG. A voltage pulse is input corresponding to the angular position M as shown in FIG. 5i. Then, the output B of the operational amplifier 224
A pulse shown in FIG. 5c is generated at point C, and this pulse is differentiated by a differentiating circuit including a capacitor 225 and a resistor 223, and a differentiated pulse shown in FIG. 5d is generated at point C.

Thus, the flip-flop circuit 23 is set by the rise of the differential pulse C to the high level at the position M, and its output voltage E becomes high level. When the output voltage E reaches a high level, the capacitor 240, which has been charged with the polarity shown in FIG. 3, begins to discharge with a current i ₂ shown in the following equation.

i ₂ = High-level output voltage of the flip-flop - (+) terminal voltage 251 of the operational amplifier 248 / resistance value of the resistor 242 As can be seen from the above equation, the magnitude of this discharge current i ₂ is determined by the resistance value of the resistor 242 being constant. If so, it depends on the (+) terminal voltage 251 of the operational amplifier 248, and in this region it depends on the output voltage 250 of the F-V circuit 25. In other words, as the engine speed increases, the discharge current i ₂ becomes smaller, and therefore the slope of the output voltage D of the operational amplifier 248 becomes gentler as shown in FIG. The angular width of becomes wider. The angular width of the high-level output voltage E obtained as described above 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.
generates a positive pulse voltage.

The flip-flop circuit 23 has an input terminal R
When the above-mentioned reset pulse is input to the circuit, it is reset and the output voltage E becomes low level.

Next, flip-flop circuit 2 is constructed as described above.
When the output voltage E of No. 3 becomes low level, the capacitor 240 shown in FIG. 3 starts to be charged again with the current i ₁ shown in the following equation in the polarity shown.

i ₁ = (+) terminal voltage 251 of operational amplifier 248 - voltage drop of diode 245 / resistance value of resistor 243 + (+) terminal voltage 251 of operational amplifier 248 / resistance value of resistor 242 As can be seen from the above equation, this charging current The magnitude of i ₁ depends on the (+) terminal voltage 251 of the operational amplifier 248 if the resistance values of the resistors 243 and 242 are constant.

That is, it depends on the output voltage 250 of the F-V circuit 23, and as the rotation speed increases, the charging current _i1 increases, and therefore the slope of the output voltage D of the operational amplifier 248 becomes steep as shown in FIG. 5e. becomes. As described above, in this rotation range, as the rotation speed increases, the angular width of the high-level output voltage E of the flip-flop 23 becomes wider.

Here, the arithmetic circuit 15 obtained by the above operation
When the output voltage E is supplied to the base of the transistor 14 through the resistor 16, the transistor 14 becomes conductive during the high level period of the output voltage E, and the signal coil 10
A part of the second angle signal b, that is, the voltage G shown in FIG. 5h, is diverted to the ground side.

In this way, when the engine speed is in the rotation range between N ₀ and N ₁ , as the engine speed increases, the falling timing of the high-level output voltage E of the flip-flop 23 is delayed, so that the timing of the conduction of the thyristor 7 is delayed. As a result, the ignition timing is retarded as indicated by 28 in FIG. 6 as the engine speed increases.

And when the engine speed reaches N ₀ rotations,
Since the output voltage 250 of the F-V circuit 25 and the (+) terminal voltage 251 of the operational amplifier 248 are constant values, the high level output voltage E of the flip-flop 23 falls at the voltage 251 which is the constant value.
It is determined by , and remains constant regardless of the increase in engine speed. Therefore, the ignition timing of the engine is determined by the constant fall timing of the high-level output voltage E, and becomes constant as shown at 29 in FIG. 6 at the retarded angle.

On the other hand, in the rotation range where the rotation speed is lower than N ₁ and higher than N ₂ , as can be seen from Fig. 4, F-
The output voltage 250 of the V circuit 25 is the bias voltage V _r1
Since the input voltage at the (+) terminal of the operational amplifier 248 is a constant value, the bias voltage _Vr1 , the output voltage 250 of the F-V circuit 25 does not affect the discharge current _i2 , and therefore the discharge current i ₂ is determined by the bias voltage V _r1 as shown in the equation below.

i ₂ = (flip-flop high level output voltage E) - V _r1 / resistance value of resistor 242 As can be seen from the above equation, in this region the discharge current
The magnitude of i ₂ is constant regardless of the rotation speed.

Also, the charging current i ₁ is also i ₁ = V _r1 − voltage drop of diode 245 / resistance value of resistor 243 + V _r1 / resistance value of resistor 242, which is determined by bias voltage V _r1 and is a constant value regardless of the rotation speed. . From the above, in this area,
The angular width of the high-level output voltage E of the flip-flop circuit 23, ie, the falling timing, is a constant value regardless of the rotation speed. At this time, the ignition timing obtained by the second angle signal b of the signal coil 10 advances as shown by the dotted line in FIG. 6, but this second angle signal b, that is, the voltage G shown in FIG. is from the rising edge of the transistor 14 (this transistor 1
The conduction angle of 4 is constant), so the conduction timing of the thyristor 7 is ultimately determined by the fall timing of the output voltage E, and the ignition timing is set at an advanced angle regardless of the engine speed. 27 is constant.

Next, in the rotation range where the rotation speed is lower than N ₂ , the discharging current i ₂ charging current i ₁ of the capacitor 240 becomes a constant value, as in the above operation, so that the angular width of the high-level output voltage E of the flip-flop circuit 23, i.e. The falling timing is a constant value regardless of the rotation speed.

On the other hand, as shown in FIG. 5g, the voltage value of the second angle signal b of the signal coil 10 is small due to the low rotational speed. When the high-level output voltage E falls, the output voltage G has not yet reached the trigger voltage V _G of the thyristor 7, and the calculation result of the calculation circuit 15 at this time does not contribute to ignition. When the second angle signal b of the signal coil 10, that is, the output voltage G reaches the trigger voltage V _G of the thyristor 7, the thyristor 7 becomes conductive;
ignite the engine.

Therefore, in such a rotation region below N ₂ ,
Second angle signal b of signal coil 10 with wide angle width
Since the conduction timing of the thyristor 7 is determined by this, a waveform advance characteristic as shown in 26 in FIG. 6 is obtained. This is because the second angle signal, which has a wide angular width, grows as the rotation increases.

As you can understand from the above operation explanation, the rotation speed is
In the rotation region until N ₂ is reached, the falling timing of the output voltage E of the arithmetic circuit 24 from the high level to the low level is constant, and the falling timing is such that the output voltage of the signal coil 10, that is, the output voltage G is constant. Since the ignition timing is until the trigger voltage V _G is reached, the ignition timing changes as shown in Fig. 6 as the output voltage waveform of the signal coil 10 grows.
6, the angle advances as the rotation speed increases. Also,
In the rotation range from N ₂ to N ₁ , as the rotation speed increases, the output voltage G reaches the trigger voltage V _G and the waveform is about to advance, or the fall timing of the arithmetic circuit 24 is determined as in the above operation. Since the ignition timing is constant, the ignition timing at this time is determined by the falling timing, and is shown in 2 in Fig. 6.
As shown in 7, the advanced angle remains constant regardless of the increase in the rotation speed, so the rotation speed increases with respect to N ₁ .
In the rotation range until N ₀ is reached, the angular width of the high-level output voltage E gradually widens, and the fall timing gradually lags as the rotation speed increases.
Since the bypass period of the second angle signal b, that is, the output voltage G becomes longer, the ignition timing is retarded as the rotational speed increases, as indicated by 28 in FIG.

Furthermore, in the rotation range where the rotational speed is _N0 or more, the falling timing becomes constant again, so the ignition timing is changed to 29 in Fig. 6.
It becomes constant at the retarded angle as follows.

The advance angle characteristic 26 of the ignition timing characteristic can be arbitrarily set by changing it according to the desired value such as the voltage waveform of the second angle signal b of the signal coil 10, and the retard characteristic 28 constant angle 27, 29 can be set as desired by It can be set arbitrarily by changing the output voltage characteristic 250 of the -V circuit 25 or the bias voltage V _r1 to change the output voltage characteristic 251 to match a desired value.

The features of this embodiment are as described above, but in addition, the armature reaction as the rotation speed increases is used as a power source for generating the second angle signal b, which is essential for determining the engine ignition timing. The generator coil 106, which is affected by Another important feature is that the other generator coil 10 (referred to as a signal coil in the explanation) that compensates the generator coil 106 can be used as the power source for the second angle signal b. For example, both the signal coil and the stator core associated with the signal coil are no longer required, the number of parts can be reduced, and the installation space is no longer required, making the design and manufacture of the magneto i extremely easy.

Conversely, if the signal coil 10 and stator core 104 that generate the second angle signal b are required due to various requirements, the second angle signal b of the signal coil 10
If the output voltage c, which is a wave opposite to the angle signal b, is used to charge the capacitor 4, the power generation coil 106 can be compensated.

In short, we focused on the fact that positive and negative AC voltages are always generated in the generator coil of magneto 1 due to its properties,
The feature of this embodiment is that one wave is used as the second angle signal b, and the other wave is used as the charging voltage of the capacitor 4.

Although the other signal coil 10 that compensates for the power generation coil 106 is installed separately from the power generation coil 106, it is also possible to overlap each other to form a two-layer structure, which is advantageous since there is no restriction on installation space. becomes. Further, the signal coil 10 can be used in conjunction with any other power generating coil exhibiting a similar power generation function, such as a power generating coil serving as a power source for lighting a lamp or the like, to obtain the same effect.

As described above, the present invention is applicable to the ignition timing characteristics of various ignition devices such as capacitor discharge type ignition, ignition coil galvanic current cut-off type ignition, and generating coil galvanic current cut-off type ignition. obtains an advance characteristic by the second angle signal, and when the rotation speed is above a predetermined rotation speed region, the ignition timing is advanced through the control circuit in accordance with the calculation signal of the ignition timing calculation circuit based on the first angle signal.
By bypassing the angle signal, at least a retard characteristic can be obtained. Moreover,
The second angular position detection device that generates the second angular signal can also improve ignition performance by generating another output that compensates for the power generating coil that serves as a power source for the ignition device.

[Brief explanation of the drawing]

FIG. 1 is an electric circuit diagram showing one embodiment of the present invention, FIG. 2 is a front view showing the structure of the first and second angular position detection devices in FIG. 1, and FIG. Figure 4 is an electrical circuit diagram showing further details of the embodiment; Figure 4 is an operation diagram showing the output characteristics of the F-V circuit in Figure 3; Figure 5 is an operating waveform explaining the operation of the embodiment in Figure 1. 6 are ignition timing characteristic diagrams obtained by this example. In the figure, 1 is a generator coil, 5 is an ignition coil, 6 is a spark plug, 7 is a thyristor, 8 and 10 are signal coils, 14 is a transistor, 15 is an ignition timing calculation circuit, 22 is a waveform shaping circuit, and 23 is a flip-flop circuit. , 24 is an arithmetic circuit, 25 is an F-V circuit,
30 is a control circuit. Note that the same reference numerals in the figures indicate the same parts.

Claims (1)

[Claims] 1. A generator coil that generates an output in synchronization with the rotation of the engine, a semiconductor switching element that controls the output of the generator coil and generates a high voltage in the ignition coil, and a predetermined crank position of the engine in synchronization with the rotation of the engine. a first angular position detection device that generates a first angular signal; and a first angular position detection device that detects the operating timing of the semiconductor switching element at a crank position that is delayed by a predetermined angle from the generation position of the first angular signal in synchronization with the rotation of the engine. a second angular position detection device that generates a controllable second angular signal; the calculation is started by the first angular signal, and from the first angular signal generation position, a function of the first angular signal generation period; an ignition timing calculation circuit that generates a calculation output having a signal width up to an angular position determined as , and control for bypassing the second angle signal by a signal obtained by the calculation result of the ignition timing calculation circuit. An engine ignition device comprising a circuit, and supplying a separate output that does not contribute to the second angle signal of the second angular position detection device as an auxiliary output to the power generation coil.