JPS6327547B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an ignition device for an internal combustion engine that can effectively control the closing angle of an ignition coil (control the energization time).

As shown in FIG. 1, a conventionally known method of closing angle control includes an alternator 1 that generates an alternating current output as shown by the solid line in FIG. 2 a in synchronization with the rotation of the internal combustion engine, and an alternating current output of the alternator 1 and a bias circuit 2 that rectifies and smoothes the voltage to generate a bias voltage V ₁ proportional to the engine speed n, and adds this DC voltage and the AC output voltage of the AC generator 1 to form a waveform in a waveform shaping circuit 3. By shaping, when the engine speed n increases, a bias voltage V ₁ is added to the AC output waveform of the alternator 1, and when the engine speed n is low, the shaded part shown in the b waveform shown in Figure 2 becomes When the engine speed n increases, the energization angle of the ignition coil 4 is increased in the shaded area as shown in the waveform c shown in FIG.
By the way, the conventional closing angle control method described above makes effective use of the output waveform of the alternator 1 itself, so as long as the alternator is used, the amount of information can be used as effectively as possible. This was the best way to do it.

However, since the cost of the alternator itself is relatively high, for example, when using a square wave signal generator using a Hall element, etc., the conventional method uses the output information of the alternator 1 too effectively. Therefore, when a signal generator that generates a rectangular wave output signal is used, there is a serious problem that the closing angle cannot be controlled.

In addition, conventional signal generators that generate rectangular wave output signals include a triangular wave generated in synchronization with the rectangular wave, and a rotation signal generated by converting the rectangular wave using a frequency-to-voltage conversion circuit. A system that controls the closing angle by comparing it with a frequency-responsive DC voltage has been considered, but since it uses a frequency-voltage conversion circuit with an integral function to obtain the rotational speed-responsive voltage, it is difficult to control the engine's sudden acceleration or deceleration. There is a problem that sometimes the response is not sufficient.

In order to solve the above problems, the present invention generates a triangular wave having a peak voltage that changes in accordance with the engine rotation speed using an ignition rectangular wave signal that is generated in synchronization with engine rotation, and the peak voltage of this triangular wave is The closing angle is controlled by comparing the voltage level-shifted by a predetermined level with the triangular wave using a comparator, and the time width standard simulates the rise time of the primary current of the ignition coil in synchronization with the comparison output of the comparator. By comparing the pulse with the output pulse width of the comparator and correcting the output pulse width of the comparator to bring it closer to the reference pulse width, it is possible to achieve optimal closing angle control from low speed to high speed even with a signal generator that generates a square wave. It is an object of the present invention to provide a closing angle control that can be carried out with sufficient responsiveness even when the engine suddenly accelerates or decelerates. Third
The figure is an electrical circuit diagram showing an embodiment of the device of the present invention. In Fig. 3, 1 is a signal generator using a Hall element or the like that generates a signal voltage in synchronization with the rotation of the engine, 2 is an input circuit that shapes the output of signal generator 1 into a rectangular wave, and 3 is an input circuit. This is a closing angle control circuit that controls the closing angle using the rectangular wave output of circuit 2. 4 is an output circuit for intermittent current flowing through the ignition coil 5 based on the output of the closing angle control circuit 3, and 6 is a battery.

Next, the closing angle control circuit 3 will be explained in detail. 7 is a triangular wave generating circuit that generates a triangular wave having a peak voltage that is almost inversely proportional to the engine speed using the rectangular wave output of the input circuit 2; 8 is a triangular wave generating circuit 7;
A peak hold circuit 9 holds the peak voltage of the peak hold circuit 8, and a voltage shift circuit 9 generates a voltage shifted by a constant voltage from the hold voltage of the peak hold circuit 8. Reference numeral 10 generates a reference pulse having a time width that simulates the primary current rise time of the ignition coil 5 based on the output of a comparator 120 that compares the triangular wave output of the triangular wave generating circuit 7 and the shifted voltage output of the voltage shift circuit 9. This is a reference pulse generation circuit. 11
compares the reference pulse width generated by the reference pulse generation circuit 10 and the output pulse width of the comparator 120, and if the reference pulse width is narrow, increases the hold voltage of the peak hold circuit 8 according to the difference in pulse width. This is a closing angle reduction circuit that performs feedback control so that the reference pulse width and the output pulse width of the comparator 120 are substantially the same. 12 compares the reference pulse width of the reference pulse generation circuit 10 and the output pulse width of the comparator 120, and when the reference pulse width is wide, lowers the hold voltage of the peak hold circuit 8 according to the difference in pulse width. This is a closing angle increasing circuit that performs feedback control so that the reference pulse width and the output pulse width of the comparator 120 are almost the same. 13 is a high-speed closing angle limiting circuit that controls the closing angle at high speed by controlling the voltage shifted by the constant voltage of the voltage shift circuit 9 so that it does not fall below a certain predetermined voltage; 14 is a hold circuit for the peak hold circuit 8; This is a low-speed closing angle correction circuit that controls so that the rectangular wave output of the input circuit 2 becomes the output of the closing angle control circuit 10 as it is when the voltage is above a certain predetermined value.
15 to 66 are resistors, 70 to 109 are transistors, 110 to 114 are capacitors, 121 is a diode, and 122 is a Zener diode.

The waveforms at points a to i in FIG. 3 are shown at a to i in FIGS. 4, 1 to 7. The operating waveform diagram in FIG. 4 shows a case where the output pulse width of the comparator 120 is larger than the reference pulse width, but the same principle operates when the output pulse width of the comparator 120 is smaller than the reference pulse width. .

Next, the operation of the above configuration will be explained.
A signal synchronized with engine rotation generated by the signal generator 1 is waveform-shaped by a waveform shaping circuit 2 into a rectangular wave signal a shown in FIG. In synchronization with the fall of this rectangular wave signal a, a narrow reset signal b shown in FIG. The transistor 76 becomes conductive in response to the reset signal b, and the charge stored in the capacitor 111 is discharged in a short time and reset to zero. Then, when the reset signal disappears, transistor 7
The capacitor 111 is charged with a constant current by a constant current charging circuit including the capacitor 4, 75 and the resistor 23. Therefore, the charging voltage C of the capacitor 111 becomes a triangular wave which is synchronized with the fall of the rectangular wave signal a and has a peak voltage inversely proportional to the engine speed, as shown by waveform c in FIG. 4. And this capacitor 111
The peak voltage of is held by the capacitor 112 of the peak hold circuit 8 as shown by the waveform d in FIG. be done. Then, the output signal voltage e of the voltage shift circuit 9 and the triangular wave voltage c of the capacitor 111 are compared by a comparator 120, and the comparison output pulse f shown in FIG.
is generated, and this comparison output pulse f causes the resistor 6 to
A signal i shown in FIG. 4 is input to the output circuit 4 through the transistors 2 and 64 and the transistors 105 and 107. When the falling point of this signal i turns ON, the output circuit 4
starts supplying the primary current to the ignition coil 5, and at the rising point S of the signal i, the output circuit 4 cuts off the primary current to the ignition coil 5 and generates a high voltage on the secondary side of the ignition coil 5. An ignition spark is generated from an ignition plug (not shown). Also, the comparison output pulse f of the comparator 120
is applied to the base of the transistor 88 of the reference pulse generating circuit 10, and at the fall of the comparison output pulse f, the transistor 89 becomes conductive for a short time, discharging the charge in the capacitor 114 and resetting it to zero.
When the transistor 89 is cut off, the resistor 43
The capacitor 114 is charged through the resistor 4, and after a predetermined time, the charging voltage of the capacitor 114 reaches the resistor 4.
When the voltage exceeds the voltage dividing points 5 and 46, transistors 90 and 91 become conductive. Therefore, the collector of the transistor 91 receives a predetermined time (approximately equal to the rise time of the primary current of the ignition coil 5) determined by the battery voltage, the time constants of the resistors 43, 44, and the capacitor 114 after the comparison output pulse f falls. The reference pulse g shown in FIG. 4 and 5 at the "1" level is generated during the period (which is preset to Then, the difference between this reference pulse g and comparison output pulse f is
OR is performed by transistors 92, 93, and 109, and an OR output h shown in FIG. 4 is obtained at the collector of transistor 109. Therefore, this OR output h is determined when the width of the "0" level of the comparison output f is wider than the width of the "1" level of the reference pulse g, that is, when the primary current conduction time of the ignition coil 5 is a predetermined value. When the difference is more than that, the time of the difference becomes "0" level. As a result, the constant current charging circuit made up of the transistors 94 and 95 and the resistor 51 is operated, and the charging voltage of the capacitor 112 is increased in proportion to the time width during which the OR output h is at the "0" level.
The primary current energization period of the ignition coil 5 is reduced. Further, the reference pulse g and the comparison output pulse f are applied to an AND circuit including transistors 100, 101, 102, and 105 to obtain an AND output. Therefore, this AND output is "1" of the reference pulse g.
When the width of the "0" level of the comparison output pulse f is narrower than the width of the level, that is, when the primary current energization time of the ignition coil 5 is less than a predetermined value, the level becomes "1" for the time corresponding to the difference. As a result, the constant current discharge circuit made up of transistors 96 to 99 and resistors 55 and 56 is operated, and the charging voltage of the capacitor 112 is decreased in proportion to the time width during which the AND output is at the "1" level, and the ignition coil 5 Increase the primary current conduction time.

Through the above operations, the primary current conduction time of the ignition coil 5 is brought closer to the primary current rise time preset by the reference pulse generation circuit 10, and
The next current application time (closing angle) can be well controlled.

In the above-mentioned embodiment, the signal generator 1 using a Hall element was described, but of course a photoelectric signal generator using a phototransistor or a signal generator consisting of an electronic advance angle control device may be used. The present invention can also be applied to a signal generator using an alternating current generator in order to standardize parts.

As described above, in the present invention, the ignition rectangular wave signal generated in the ignition rectangular wave signal generator in synchronization with the engine rotation generates a triangular wave having a peak voltage that changes in accordance with the engine rotation speed. The peak voltage of this triangular wave is held in a peak hold circuit, and the voltage shift circuit generates a voltage that is shifted by a predetermined level from the peak voltage held in this peak hold circuit, and this shifted voltage and the triangular wave are connected to a comparator. Determine the energization time of the ignition coil by comparing, and further,
In synchronization with the output pulse of the comparator, a reference pulse with a time width that simulates the rise time of the primary current of the ignition coil is generated in the reference pulse generation circuit, and this reference pulse width is compared with the output pulse width of the comparator. Since the peak voltage is corrected by the correction circuit in order to bring the output pulse width of the comparator closer to the reference pulse width, even a signal generator that generates a square wave can perform optimal closing angle control from low speed to high speed. With,
The correction of the peak voltage has an excellent effect in that closing angle control can be performed with sufficiently quick response even when the engine is rapidly accelerating.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a conventional device, FIG. 2 is a waveform diagram of each part showing the operating principle of the conventional device, FIG. 3 is an electric circuit diagram showing an embodiment of the device of the present invention, and FIG. FIG. 3 is a waveform diagram of each part showing the operating principle of the illustrated device of the present invention. 1, 2...Signal generator and input circuit constituting an ignition square wave signal generator, 5...Ignition coil, 7
... Triangular wave generation circuit, 8 ... Peak hold circuit, 9 ... Voltage shift circuit, 10 ... Reference pulse generation circuit, 11, 12 ... Closed angle reduction circuit and closed angle increase circuit forming the correction circuit, 120 ... ...Comparator.

Claims (1)

[Claims] 1. An ignition square wave signal generator that generates an ignition square wave signal in synchronization with the engine rotation, and a peak voltage that changes in accordance with the engine rotation speed in synchronization with the ignition square wave signal from this signal generator. A triangular wave generating circuit that generates a triangular wave with a comparator that generates an output pulse by comparing the shift voltage from the voltage shift circuit with the triangular wave from the triangular wave generating circuit; and an ignition coil whose primary current is controlled by the output pulse from the comparator. , a reference pulse generation circuit that generates a reference pulse having a time width that simulates the primary current rise time of the ignition coil in synchronization with the output pulse of the comparator, and a reference pulse width of the reference pulse generation circuit and the comparator. and a correction circuit that corrects the peak voltage of the peak hold circuit in order to bring the output pulse width of the comparator closer to the reference pulse width of the reference pulse generation circuit by comparing the output pulse width of the comparator with the output pulse width of the reference pulse generation circuit. Engine ignition system.