JPS6160984B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an engine ignition timing control device, and particularly to an engine ignition timing control device that electronically controls the ignition timing in accordance with the rotation of the engine. This type of conventional device uses only a mechanical governor device or an integral circuit in which the rotation speed and voltage are directly proportional to the engine speed detection circuit, and only a linear ignition characteristic or a curved ignition characteristic can be obtained. However, it was difficult to obtain the desired characteristics. The present invention has been made to eliminate such conventional drawbacks, and an object of the present invention is to provide an engine ignition timing control device that can stably and accurately obtain desired curved ignition characteristics. Hereinafter, a detailed description will be given with reference to the embodiments shown in FIGS. 1, 2, and 3. In the figure, reference numeral 1 denotes a stator of a magnet generator, which has a generating coil 2 for ignition and charging, a first signal coil 3, and a second signal coil 4. Reference numeral 5 denotes a well-known capacitor discharge type ignition circuit which uses the output of the generator coil 2 as a power source, and the generation timing of the ignition voltage of this ignition circuit (substantially the ignition timing of the engine) is determined by the ignition at the gate 5b of the thyristor 5a. It is time for the signal to be input and the thyristor 5a to turn on. 6,7
8 is a diode and a resistor connected between the first signal coil 3 and the gate 5b of the thyristor 5a, and 8 is an ignition timing control circuit that electronically controls the ignition timing of the engine based on the engine speed. Its input end is
It is connected to the second signal coil 4 via a diode 9, and its output end is connected to the gate 5b of the thyristor 5a. The ignition timing control circuit 8 is configured as follows. 10 is a waveform shaping circuit that shapes the rectified wave of the second signal coil 4; 11 is a flip-flop circuit (hereinafter referred to as an F.F circuit) that receives the output of this waveform shaping circuit 10; and 12 is this F.F.
Resistors 121, 122, 1 are connected to the arithmetic circuit that receives the output based on the engine speed from the F circuit 11 and performs calculations.
23, diodes 124 and 125, a transistor 126, a capacitor 127, an operational amplifier (hereinafter referred to as an operational amplifier) 128, and a voltage comparator (hereinafter referred to as a comparator) 129. Note that the input terminals (+) of the operational amplifier 128 and the comparator 129 are biased to the comparison voltage _Vr1 .
Reference numeral 13 denotes a rotation speed-voltage conversion circuit (hereinafter referred to as an FV circuit) that generates a DC voltage using rotation as a function, and is composed of an integrating circuit 131 and a square root circuit 132. Reference numeral 14 denotes an output circuit that receives an output pulse based on the calculation result of the calculation circuit 12 and outputs a gate signal for the thyristor 5a, and this output becomes the output of the ignition timing control circuit 8. This output circuit 14 includes a transistor 141, resistors 142, 143, and a capacitor 14.
4 and a diode 145. Next, the operation will be explained using the time chart shown in FIG. Figure 6A shows the engine crank position, where M is a position slightly advanced from the maximum advance position required by the engine, S is the required ignition position at low engine speeds, and T is the top dead center of the engine. be. Also, B~H
are the voltage and pulse waveforms at each point in FIG. The engine requires the X or Y advance characteristics shown in FIG. When the magnet generator is driven by the engine, the generator coil 2, the first signal coil 3, and the second signal coil 4
AC voltage is generated. Regarding the phase of the two signal coils, a signal output is first generated in the second signal coil 4, and a signal output is generated in the first signal coil 3 after a delay of a predetermined angle θ. These signal outputs are the sixth
It is rectified by diodes 6 and 9 as shown in Figures B and H. Now, assuming that the engine speed N is at a constant speed higher than _N1 , and that the advance angle at this time is at a position advanced by an angle α from the T position, the operation will be as follows. That is, the rectified voltage B of the second signal coil 4 is shaped into a differential pulse by the waveform shaping circuit 10 as shown in FIG.
is input. The FV circuit 13 outputs a voltage corresponding to the engine speed N. The output voltage V ₁₃ of this F-V circuit 13 is as shown in Figure 5.
The output curve is shown by the line. The FF circuit is set by the H level of the differential pulse C at the M position, and its output voltage E becomes H level. When this output voltage E becomes H level, the transistor 126
is forward biased through the low resistor 122 and turned on. When the transistor 126 is turned on, the capacitor 127, which has been previously charged to the polarity shown in the figure, starts discharging at a current i ₂ expressed by the following equation.

[Table] As can be understood from the above equation, the magnitude of this discharge current i ₂ is determined by the bias voltage Vr ₁ (this Vr ₁ is for the F-V circuit shown in Fig. 2 and the F-V circuit shown in Fig. 3). (different for the circuit), resistors 121, 12
If the resistance value of V 2 is constant, it is determined by the output voltage V ₁₃ of the FV circuit 13. capacitor 12
7, the output voltage D of the operational amplifier 128 drops as shown in FIG. 6, and when the output voltage D reaches the bias voltage _Vr1 , a positive pulse voltage is generated at the output of the comparator 129. When this pulse voltage is input to the reset terminal R of the FF circuit 11, the FF circuit 11 is reset, its output voltage E is inverted to L level, and the transistor 126 is turned off, so that the input terminal of the operational amplifier 128 is inputted. (-)
The output voltage V ₁₃ of the FV circuit 13 is prevented from being applied to the FV circuit 13 . Therefore, the output voltage D of the operational amplifier 128 increases, and as a result, the capacitor 127 starts to be charged again with the current i ₁ shown in the following equation in the polarity shown. i ₁ = Vr ₁ - Voltage drop of diode 125/resistance 1
Resistance value of 23 As can be understood from the above equation, the magnitude of this charging current i ₁ is constant regardless of the engine speed N. Therefore, the charging voltage of the capacitor 127, ie, the output voltage D of the operational amplifier 128, increases linearly with a constant slope regardless of the engine speed N, as shown in FIG. Then, when the differential pulse C is again input to the FF circuit 11 at the M position, the F-circuit 11 is set and its output voltage E is inverted from the L level to the H level, so that the capacitor 127 changes from charging to discharging. After that, the same operation will be repeated. The time width T of the H level output voltage E of the FF circuit 11 obtained by the above-described operation is determined by the calculation circuit 12.
As can be understood from the above explanation of the operation, the output voltage V ₁₃ of the F-V circuit 13 increases as the engine speed N increases. becomes narrower as the proportion increases. The operation of the FV circuit 13 shown in FIG. 2 having the x-curve output voltage characteristic shown in FIG. 5 is as follows. When the H and L pulses of the FF circuit 11 are applied to the input terminal of the integrating circuit 131, a DC voltage proportional to the number of pulses is applied to the integrating circuit 131.
Furthermore, this proportional output is output from the square root circuit 1
32 and output as a square root value.
Further, the operation of the FV circuit 13 shown in FIG. 3 having the output voltage characteristic of the y-curve shown in FIG. 5 is as follows. That is, when the H and L pulses of the FF circuit 11 are applied to the input terminal of the integrating circuit 133, a DC voltage proportional to the number of pulses is output, and this proportional output is then squared by the square circuit 134. It is output as a value. Therefore, the H level time width T of the calculation output voltage E of the calculation circuit 12 becomes narrower according to the square or square value. When the output voltage E of the FF circuit 11 is inverted from the L level to the H level, a base current is applied to the transistor 141 of the output circuit 14 through the resistor 143, and the transistor 141 is turned on. Therefore, the electric charge of the capacitor 144 charged to the illustrated polarity is discharged through the transistor 141 and the diode 145, and finally the F point potential becomes L level, and the G point potential becomes the voltage drop across the diode 145. . Also, F
- When the F circuit 11 is reset and reversed from the H level to the L level, the base current of the transistor 141 is not applied and the capacitor 144 is turned off through the resistor 142 from a constant power source (not shown), and the capacitor 144 is charged again to the polarity shown in the drawing from a constant power source (not shown). The potential at point F becomes H level, and therefore a large trigger voltage is generated at point G as shown in FIG. 6G. That is, the output circuit 14
- The output voltage E of the F circuit 12 is input, the pulse falling timing from the H level to the L level of the output voltage E is detected, and the thyristor 5a is activated at the falling timing.
This outputs a trigger voltage G of . The timing at which this trigger voltage G is generated becomes earlier as the engine speed N increases. This rotation speed range N ₁ ~ _{N 2}
As shown in FIG. 4, the advance angle characteristic is a curve X or Y having a predetermined slope from _N1 to _N2 . Therefore, when the engine speed N becomes equal to or higher than _N2 shown in _FIG . The magnitude of the current i ₂ is constant, so the timing at which the output voltage E of the FF circuit 11 changes from H level to L level is always constant (substantially) regardless of the increase in engine speed N. , the time width T of the H level is constant in a narrow state), so that a large trigger voltage is always generated at the same time at the G point of the output circuit 14, so that the advance angle becomes constant. Now, the signal output of the first signal coil 3 is shown in Figure 6H.
This occurs at point S as shown in . This signal output is applied to the gate 5b of the thyristor 5a via the diode 6 and the resistor 7, turning on the thyristor 5a, and its ignition timing is constant regardless of the engine speed N. Therefore, now, at engine speed N ₁ , the signal output of the second signal coil 4 outputs the output that turns on the thyristor 5a of the 8th ignition timing control, and the output that turns on the thyristor 5a of the first signal coil 3. If the timing _of output generation is set to match, the first signal coil 3 will be
The thyristor 5a is turned on more quickly due to the Therefore, the ignition timing of the engine is determined by the signal output of the first signal coil 3, and this ignition timing is constant with respect to the engine rotation speed N, as shown in FIG. Note that the present invention is not limited to the above-mentioned embodiments, but includes various embodiments. For example, in addition to the capacitor discharge type, the ignition circuit can also be applied to a current interrupt type. Further, as a means for obtaining two signal outputs, a signal generator may be provided outside the magnet generator. As described above, according to the present invention, in order to obtain the curved ignition timing characteristics required by the engine, the engine receives the first signal from the first signal generating means and the second signal from the second signal generating means. The ignition signal output of the ignition timing control circuit that operates in response to the engine speed is commonly input to the semiconductor switching means, and when the engine speed is below a predetermined engine speed, the first signal is switched to the semiconductor switching means earlier than the ignition signal output. input into the switching means,
When the engine speed is above a predetermined speed, the ignition signal output is inputted to the semiconductor switching means earlier than the first signal, and the speed and voltage are directly proportional to the rotation function circuit that detects the engine speed of the ignition timing control circuit. Since the circuit is connected in series with an integrating circuit that outputs a square or square root circuit whose output voltage is the square or square root of the input voltage, it is possible to control the rotation speed and voltage in a conventional mechanical governor device or rotation function circuit. It is possible to accurately and stably obtain the desired curved ignition timing, which could not be achieved by a device having only an integral circuit in which the ignition timing is directly proportional, and it is possible to appropriately control the engine.

[Brief explanation of the drawing]

Fig. 1 is an electric circuit diagram showing one embodiment of the present invention, Fig. 2 is a partial circuit diagram of Fig. 1, and Fig. 3 is a partial circuit diagram of Fig. 1.
4 is an ignition timing characteristic diagram required by the engine; FIG. 5 is a characteristic diagram of the output voltage V ₁₃ of the F-V circuit 13 shown in FIGS. 2 and 3; FIG. 6 is an explanatory diagram illustrating the operation of the circuit of FIG. 1. In the figure, 2 is a generator coil, 3 is a first signal coil, 4 is a second signal coil, 5 is an ignition circuit, 8 is an ignition timing control circuit, 10 is a differential circuit, and 11 is F-
F circuit, 12 is arithmetic circuit, 13 is F-V circuit, 1
4 is an output circuit, 131, 133 is an integration circuit, 13
2 is a square root circuit, and 134 is a square circuit. In each figure, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A first signal generating means that generates a first signal at a predetermined crank position of the engine; a second signal generating means that generates a second signal at a crank position that is a predetermined angle ahead of the predetermined crank position of the engine; This second
an ignition timing control circuit that receives the signal as a rotational signal and outputs an ignition signal at a timing corresponding to the rotational speed of the engine; and an ignition timing control circuit that commonly receives the first signal and the ignition signal output of the ignition timing control circuit. In the engine ignition timing control device, the engine ignition timing control device is equipped with a semiconductor switching means that operates to generate an ignition voltage in the ignition coil, and the rotation function circuit for detecting the engine rotation speed of the ignition timing control circuit includes an integral circuit and a square root circuit or a square root circuit. An engine ignition timing control device characterized by connecting in series.