JPS6231670Y2 - - Google Patents

Description

[Detailed explanation of the idea]

The present invention relates to a non-contact type internal combustion engine ignition device. In particular, it relates to something 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 angles 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, The drawback was that it was unable to meet that demand. This invention eliminates the above drawbacks and provides an internal combustion engine ignition system that can obtain extremely accurate ignition timing characteristics from low speeds to high speeds. This invention will be described below with reference to embodiments shown in FIGS. 1 to 6. First, in FIG. 1 showing a CDI type magneto ignition system, reference numeral 1 denotes a magneto power generation coil (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 and 3 are diodes that rectify the output of this generator coil, 4
is a capacitor charged by the output of the generator coil 1 rectified by this diode 2, 5 is an ignition coil connected to the discharge circuit of the capacitor, and a primary coil 5a/spark plug 6 connected in series with the capacitor 4. Secondary coil 5 connected to
It consists of b. A thyristor 7 is a switching element provided in the discharge circuit of the capacitor 4. 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 an ignition signal, which is an engine angular position detection device, and is synchronized with the rotation of the engine and generates first and second angle signals a and b corresponding to a predetermined crank position of the engine. . Diodes 9, 10 and 11, 12 divide the angle signal into a positive signal and a negative signal. 13 is a resistor inserted between the diode 9 and the gate pole of the thyristor 7; 14;
Reference numeral 15 denotes an ignition timing calculation circuit and a calculation output control circuit inserted between the diode 11 and the gate pole of the thyristor 7. FIG. 2 is a detailed circuit diagram of the ignition timing calculation circuit 14 and the calculation output control circuit 15.
0 is a waveform shaping circuit that shapes the output of the signal coil 8, and includes registers 201, 202, 206,
Voltage comparator (hereinafter referred to as comparator) 204,
It consists of a capacitor 205 and a diode 207.
21 is an RS flip-flop circuit; 22 is an arithmetic circuit that is connected to this flip-flop circuit 21 and generates a predetermined output according to the engine speed; registers 221, 223, 227, 228, 229;
Diodes 222, 230, capacitor 224,
It consists of an operational amplifier (hereinafter referred to as an operational amplifier) 225 and a voltage comparator (hereinafter referred to as a comparator) 226. Reference numeral 24 denotes a rotation speed-voltage conversion circuit (hereinafter referred to as an F-V circuit) which captures the shaped output of the output signal a of the signal coil 8 as a rotation speed signal and converts it into a DC voltage proportional to the rotation speed. One input terminal S of the flip-flop circuit 21 is connected to the output terminal of the waveform shaping circuit 20, and the other input terminal R
is connected to the output terminal of the comparator 226. Further, one output terminal Q of the flip-flop 21 is connected to an operational amplifier 225 via a register 221.
is connected to the inverting input terminal (hereinafter referred to as the (-) terminal) of the diode 222 and the resistor 22.
It is connected to the (-) terminal of the operational amplifier 225 through a series circuit of No. 3. The above operational amplifier 2
25 non-inverting input terminals (hereinafter referred to as (+) terminals)
is connected to the output terminal of the F-V circuit 24 via a resistor 229 and a diode 230, and is biased by dividing a constant voltage power supply (not shown) by registers 227 and 228. The output terminal of the operational amplifier 225 is the comparator 226
It is connected to the (-) terminal of the operational amplifier 225 via the capacitor 224. The (+) terminal of comparator 226 is grounded. The output terminal Q of the flip-flop 21 is connected to the F-V circuit 24 and the base of a transistor 153 via a resistor 151, and the collector of the transistor 153 is connected to a constant voltage power supply via a resistor 152.
5 to the gate of the thyristor 7. The base of the transistor 153 and the output terminal of the F-V circuit 24 are connected through a diode 157.
The emitter of is grounded via a diode 154. Further, a diode 156 is connected between the connection point between the capacitor 155 and the gate of the thyristor 7 and the ground. FIG. 3 shows the output characteristics of the F-V circuit 25. FIG. 4 shows output waveforms at each point A to G of the circuit shown in FIG. 2, where the horizontal axis is time and the vertical axis is a time chart of voltage. Further, FIG. 5 is a lead angle characteristic diagram of the embodiment shown in FIG. Next, the operation of the embodiment will be explained. First, in the CDI type ignition system shown in FIG.
is charged to the polarity shown, and the charged charge is used as the ignition timing of the engine, that is, at the output generation timing of the ignition timing calculation circuit 14 which inputs the output voltage a of the signal coil 8, or at the generation timing of the output voltage b of the signal coil 8. , the thyristor 7 is made conductive and the primary coil 5 of the ignition coil 5 is
A, the secondary coil 5b generates a high voltage, and a spark is emitted to the spark plug 6. Now, the conduction timing control of the thyristor 7, that is, the ignition timing control, which is the gist of this invention, will be explained in detail with reference to FIGS. 3, 4, and 5. First, the timing at which the signal output a of the signal coil 8 is generated is at a position M which is advanced from the top dead center position T of the engine as shown in FIG. A position S is later than the occurrence position M of a and earlier than the T position. The signal output a generated at the M position is converted into a differential pulse by the waveform shaping circuit 20 and applied to the S terminal of the flip-flop 21. Flip-flop 21 is set when an input is applied to the S terminal. That is, the output voltage of the output terminal Q becomes a high level (hereinafter referred to as H level). When the Q terminal becomes H level, the charge in the capacitor 224, which has been charged to the polarity shown in FIG. 2 via the resistor 221, begins to be discharged by a current i ₂ expressed by the following equation. i ₂ = H level output voltage value of flip-flop 21 - (+) terminal voltage value of operational amplifier 225 / resistance value of register 221

Resistance value of [Table] As can be understood from the above equation, the magnitude of this charging current i ₁ depends on the (+) terminal voltage value of the operational amplifier 225 if the resistance values of the resistors 221 and 223 are constant. Therefore, similarly to the discharge current i ₂ , N ₂ rotations or less are determined by the voltage Vr ₂ , and N ₂ rotations or more are determined by V _FV . On the other hand, when the rectangular wave output of the flip-flop 21 is applied to the transistor 153 via the register 151, the L-H level is inverted, so the capacitor 155 is charged from the moment the flip-flop 21 becomes the L-level output, and the The moment the voltage reaches the level, the capacitor 155 is discharged. Therefore, the waveform at point E in FIG. 2 is as shown in FIG. 4E. Here, when the output of the F-V circuit 24 is lower than the sum value Vr ₁ of the voltage drop between the base and emitter of the transistor 153 and the voltage drop of the diode 154, that is, when it is less than N ₁ rotation, Even when the flip-flop 21 becomes H level, the base current of the transistor 153 is bypassed to the FM circuit 24 via the diode 157, so the transistor 153 does not conduct. Therefore, the differential wave as described above does not appear in the waveform at point E in FIG. As described above, the ignition timing calculation circuit 14 and the calculation output control circuit 15 are controlled by the output of the F-V circuit 24. That is, at the end of _N1 rotations, the output of the ignition timing calculation circuit 14 based on the a output of the signal coil 8 is not given to the gate of the thyristor 7, so the thyristor 7 is operated only by the b output of the signal coil 8. Conducted. In other words, the ignition occurs at the ignition position S for N1 rotation or less in Fig. ₅ . In the N ₁ to N ₂ rotation range, both the output E of the ignition timing calculation circuit 14 and the b output of the signal coil 8 are given to the gate of the thyristor 7, but since the output E of the ignition timing calculation circuit 14 is earlier, the thyristor 7 conducts through E. Furthermore, as mentioned above, in the rotation range from N ₁ to N ₂ , the output voltage of F-V (V _FV ) is less than Vr ₂ , so the operational amplifier 22
The (+) terminal voltage of 5 is always Vr ₂ . Therefore, since the current ratio i ₁ /i ₂ of charging and discharging the capacitor 224 does not change with respect to the rotation speed, the charging and discharging time ratio of the capacitor 224 also remains unchanged. That is, the crank angle starting from the M position until the discharge of the capacitor 224 is completed remains constant. Therefore, in Figure 5
As shown from _N1 to _N2 , a constant ignition position is reached at a position advanced from the S position. In the rotation range from N ₂ to N ₃ , the output voltage V _FV of the F-V circuit 24 exceeds Vr ₂ , so the charging/discharging ratio of the capacitor 224 changes. Since this amount of change is inversely proportional to V _FV ,
As shown from N ₂ to N ₃ in Figure 5, the ignition position is delayed. N As long as the output voltage V _FV of the F-V circuit 24 increases even after ₃ rotations, the ignition timing calculation circuit 14
Although the timing of output generation is delayed, if it matches the b output of the signal coil 8 at _N3 rotations and is delayed thereafter, the thyristor 7 is conductive by the b output of the signal coil 8, so the fifth As shown in the figure, the ignition position becomes constant again at the S position. In the above, even if the signal coil 8 is provided separately to obtain the a output and the b output, the same effect can be obtained.
Furthermore, the ignition device is not limited to CDI, but any ignition device, such as a current cutoff type ignition device using a transistor, will have the same effect. As described above, this invention allows the advance/retardation characteristics required by the engine to be controlled in response to the output of the rotation speed/voltage conversion circuit, making it possible to follow engine speed fluctuations extremely accurately. I can do things.
Furthermore, since the electric circuit shown in FIGS. 1 and 2 operates satisfactorily even when the signal coil output for setting the crank angle is a short pulse with a short duration, the positional accuracy of the ignition timing can be improved. In addition, the ignition timing can be easily changed by simply changing the rated values of some parts in the ignition timing calculation circuit (registers 221 and 223 in this embodiment) without changing the angular positions of the a and b outputs of the signal coil. I can do it.

[Brief explanation of the drawing]

FIG. 1 is an electric circuit diagram showing an embodiment of this invention, FIG. 2 is an electric circuit diagram showing further details of the embodiment in FIG. 1, and FIG. 3 is an output of the F-V circuit 24 of FIG. 3. FIG. 4 is an operation waveform diagram explaining the operation of the embodiment of FIG. 1, and FIG. 5 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,
9, 10, 11, 12 are diodes, 13 is a register, 14 is an ignition timing calculation circuit, 15 is a calculation output control circuit, 20 is a waveform shaping circuit, 21 is a flip-flop, 22 is a calculation circuit, and 24 is an F-V circuit. be. In addition, in the figures, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims for Utility Model Registration] (1) A switching element that controls energization from a power source to an ignition coil, and a first angle signal that is synchronized with the rotation of the engine and that generates a first angle signal that corresponds to a predetermined crank position of the engine. a second angular position detecting device that generates a second angular signal corresponding to a crank position that is synchronized with the rotation of the engine and delayed by a predetermined angle from the first angular signal; an ignition timing calculation circuit that starts calculation based on the angle signal of the engine and calculates the ignition retard amount required by the engine; a control circuit that bypasses the output of the ignition timing calculation circuit at a predetermined rotation speed or less; An internal combustion engine characterized in that the second angle signal is given to the switching element as a rotation signal, and the first angle signal is given as an angle signal after passing through the ignition timing calculation circuit and the control circuit. Engine ignition system. (2) Utility model registration claim 1, characterized in that the angular position detection device is a single detection device in which the first angular signal is a polar wave on one side and the second angular signal is a polar wave on the other side. internal combustion engine ignition system. (3) The internal combustion engine ignition system according to claim 1 or 2, wherein the control circuit is operated in response to the rotation speed-voltage conversion amount of the ignition timing calculation circuit.