JPH0231792B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention uses an exciter coil as a power source that induces an alternating current voltage in synchronization with the rotation of an internal combustion engine, and a signal that induces a signal in synchronization with the rotation of the engine. The present invention relates to an ignition device for an internal combustion engine that uses a coil as a signal source to generate a high voltage to be applied to a spark plug for engine ignition at the ignition timing of the engine by controlling the primary current of the ignition coil.

[Prior Art] In an ignition system for an internal combustion engine, it is necessary to control the ignition timing of the engine according to the engine rotation speed (rpm), and it is necessary to use an ignition system that has ignition characteristics that meet the requirements of the engine. It is necessary to prepare. One of the ignition characteristics often requested by engines is the characteristic of advancing the ignition timing in steps when the engine speed reaches a set value. Conventional ignition systems that achieve this type of ignition characteristic detect the engine speed and advance the ignition timing by a predetermined angle when the engine speed reaches a set value. Since the rotation speed was detected by the output of an exciter coil that supplied energy or the output of a signal coil that obtained an ignition signal, the gap between the rotor and stator of a generator equipped with an exciter coil or signal coil was It is unavoidable that errors occur in the detected value of the rotational speed due to variations in waveforms due to fluctuations, etc., and attempts to avoid this have the drawback of complicating the circuit and making the device expensive.

[Object of the Invention] An object of the present invention is to provide an ignition device for an internal combustion engine that has a simple configuration and can perform accurate step advance operation without being affected by the waveform of a generator. be.

[Structure of the Invention] The ignition device for an internal combustion engine to which the present invention is directed uses an exciter coil that induces an alternating current voltage in synchronization with the rotation of the internal combustion engine as an ignition power source, and operates when an ignition signal is applied to a control signal input terminal. an ignition circuit that controls the primary current of an ignition coil to perform an ignition operation using a semiconductor switch; and an ignition timing determination circuit that receives the output of the signal coil induced at angular intervals and supplies the ignition signal to the primary current control semiconductor switch to determine the ignition timing. It is as shown below.

(a) The ignition timing determining circuit is configured to: (a) supply the ignition signal to the primary current control semiconductor switch with the second polarity signal generated from the signal generated from the signal coil; (b) the first signal having a phase lead than the second signal;
a second signal supply circuit that supplies the ignition signal to the primary current control semiconductor switch when a signal of polarity is generated; and a capacitor charging circuit that charges the integrating capacitor to one polarity with the output of the exciter coil at a constant time constant; (b) a pump power supply that charges the integrating capacitor to one polarity with the output of the exciter coil; a pump circuit comprising: a capacitor; a pump-up switch circuit that conducts when triggered by the signal of the first polarity; and a pump-up capacitor that is charged through the pump-up switch circuit with the charge of the pump power supply capacitor; a reset circuit that instantaneously discharges the integrating capacitor and the pump-up capacitor when a signal of a second polarity is generated; (d) a triangular wave voltage obtained across the integrating capacitor and a rectangular wave voltage obtained across the pump-up capacitor; a comparator circuit for comparing the triangular wave voltage with the triangular wave voltage; (f) a charging time constant of the integrating capacitor is set so that the rectangular wave voltage exceeds the triangular wave voltage at the rising edge when the rotational speed of the internal combustion engine exceeds a set value; ing.

[Operation of the invention] In the above configuration, the basic operation of the ignition device is the same as that of the conventional device, and an ignition signal is sent from the ignition timing determining circuit to the semiconductor switch for primary current control of the ignition circuit at the ignition timing of the engine. When supplied, the primary current control semiconductor switch operates to control the primary current of the ignition coil and induce a high voltage for ignition in the secondary coil of the ignition coil. This generates a spark in the spark plug attached to the cylinder of the engine, igniting the engine.

In the ignition system of the present invention, when a voltage is generated in the exciter coil in synchronization with the rotation of the engine, the integrating capacitor of the integrating circuit is charged to one polarity in one half cycle of the voltage, and the terminal voltage of the integrating capacitor is It rises at a constant slope. Since the charge in this integrating capacitor is instantly discharged by the reset circuit when a signal of the second polarity is generated from the signal coil, the terminal voltage of the integrating capacitor is A triangular wave voltage rises at a constant slope until a signal of polarity 2 is generated.

On the other hand, in the pump circuit, the pump power supply capacitor is charged to one polarity by the output of the exciter coil. When the signal coil generates a signal of a first polarity, the pump up switch circuit conducts and transfers the charge on the pump power supply capacitor to the pump up capacitor, instantaneously charging the pump up capacitor. When a signal of the second polarity is generated from the signal coil, the reset circuit instantly discharges the electric charge of the pump-up capacitor, so that the terminal voltage of the pump-up capacitor rises at the position where the signal of the first polarity is generated, and then rises to the second polarity. It becomes a rectangular wave voltage that falls at the position where the signal is generated.

The rectangular wave voltage and triangular wave voltage are supplied to a comparison circuit. If the engine speed is less than the set value, the above rectangular wave voltage cannot exceed the triangular wave voltage at its rise, so the trigger circuit
Do not supply the ignition signal to the semiconductor switch for controlling the next current. Therefore, in a low-speed rotation region where the engine speed is less than the set value, an ignition signal is given to the primary current control semiconductor switch by a signal of the second polarity from the first signal supply circuit, and the ignition signal of the second polarity is applied. Ignition occurs at the location where the signal is generated.

When the engine speed exceeds the set value, the rectangular wave voltage exceeds the triangular wave voltage at the rise of the rectangular wave voltage, so the comparator circuit causes the trigger circuit to output an ignition signal, and the ignition signal becomes 1. The next current is supplied to the semiconductor switch for current control. Therefore, in the rotation range where the engine speed exceeds the set value, ignition will occur at the position where the first polarity signal is generated (at the rise of the square wave voltage), and the engine ignition timing will match the set speed. The angle will advance in steps.

[Examples] Examples of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows an embodiment of the present invention, in which 1 is an ignition coil having a primary coil 1a and a secondary coil 1b, and 2 is an ignition coil 1 attached to a cylinder of an engine (not shown). The spark plug is connected to the secondary coil of the One ends of the primary coil 1a and the secondary coil 1b are grounded, and one end of the ignition energy storage capacitor 3 is connected to the non-grounded terminal of the primary coil 1a. A discharge control thyristor 4 is connected between the other end of the capacitor 3 and the ground, with its cathode facing the ground, and the cathode of a diode 5 is connected to the connection point between the anode of the thyristor 4 and the capacitor 3. One end of the exciter coil 6 is connected to. The other end of the exciter coil 6 is a thyristor 4
A diode 7 with its anode facing the ground side is connected between the cathode of the diode 5 and the ground. A resistor 8 and a capacitor 9 are connected in parallel between the gate and cathode of the thyristor 4. The exciter coil 6 is provided in a magnet generator that rotates synchronously with the engine, and generates an alternating current voltage Vx in synchronization with the rotation of the engine, as shown in FIG. 2E. The ignition circuit 10 is constituted by each of the above parts.

In the ignition circuit 10, the exciter coil 6, the diode 5, and the capacitor 3 constitute a power supply circuit that causes the primary current to flow through the ignition coil 1, and the discharge control thyristor 4 causes the primary current to suddenly change at the ignition timing. It constitutes a semiconductor switch for controlling the primary current. This ignition circuit is well known as a capacitor discharge type ignition circuit, and in this ignition circuit, the capacitor 3 is charged to the polarity shown by the half-cycle output of the exciter coil 6 in the direction of the arrow shown in the drawing. The change in the terminal voltage V3 of the capacitor 3 with respect to the rotation angle θ is shown in FIG. 2F. Next, when an ignition signal (signal for determining the ignition timing) is supplied to the gate of the thyristor 4 from the ignition timing determination circuit described later, the thyristor 4
conducts, and the charge in the capacitor 3 is discharged through the thyristor 4 and the primary coil 1a of the ignition coil 1. Since this discharge occurs instantaneously, a large magnetic flux change occurs in the iron core of the ignition coil 1, and a high voltage for ignition is induced in the secondary coil 1b. Since this high voltage is applied to the ignition plug 2, a spark is generated in the ignition plug and the engine is ignited.

A cathode of a diode 11 is connected to the gate of the thyristor 4 of the ignition circuit 10, and an anode of the diode 11 is connected to one end of a signal coil 12. The other end of the signal coil 12 is the thyristor 4
connected to the cathode (ground) of the The signal coil 12 is provided in a signal generator that rotates in synchronization with the rotation of the engine, and as shown in FIG.
and are generated sequentially. Here, the signal generator generates a signal Vs1 of the first polarity at the ignition timing θi1 in the medium-high speed region of the engine (region above the set rotation speed), and generates a signal Vs2 of the second polarity at the ignition timing θi1 when the engine is at low speed. Ignition timing θi2 (θi1
It is configured so that it occurs at an angle closer to the top dead center of the engine. This signal generator may be provided separately from the magnet generator provided with the exciter coil, or may be constructed using a part of the rotor magnetic poles of the magnet generator. In this example, signal coil 1
2 and the diode 11 constitute a first signal supply circuit that supplies an ignition signal to the thyristor 4 using a second signal obtained from the signal coil 12.

The anode of a diode 20 is grounded to the non-grounded terminal of the exciter coil 6, and the cathode of the diode 20 is connected to one end of a power supply capacitor 22 via a resistor 21. The other end of the power supply capacitor 22 is grounded, and Zener diodes 23 with anodes facing the ground are connected in parallel to both ends of the power supply capacitor 22. A voltage dividing circuit consisting of a series circuit of resistors 24 and 25 is connected in parallel to both ends of the Zener diode 23, and the base of a transistor 26 is connected to a voltage dividing point of the voltage dividing circuit. The emitter of transistor 26 is resistor 2
7 to the cathode of a Zener diode 23, and an integrating capacitor 28 is connected between the collector of the transistor and ground. An integrating circuit 30 is constituted by each component from the diode 20 to the integrating capacitor 28. In this integrating circuit, a diode 20, a resistor 21, a capacitor 22, and a Zener diode 23 constitute a power supply circuit that uses the exciter coil 6 as a power supply, and this power supply circuit, a transistor 26, and resistors 24, 25
and 28 constitute a capacitor charging circuit that charges the integrating capacitor with a constant time constant. The waveform of the voltage V22 across the capacitor 22 changes as shown in FIG. 2G with respect to the rotation angle θ of the engine. This voltage charges the integrating capacitor 28 with a constant current through the transistor 26, and the voltage at the terminal of the capacitor 28 rises at a constant slope as shown in FIG. 2B.

One end of a resistor 31 is connected to the cathode of the diode 20, and the other end of the resistor 31 is connected to one end of a pump power supply capacitor 32. The other end of the capacitor 32 is grounded, Zener diodes 33 are connected to both ends of the capacitor 32 with their anodes facing the ground side, and the collector of a transistor 34 is connected to the non-ground terminal of the parallel capacitor 32. is connected to the cathode of a diode 35 whose anode is grounded. A capacitor 36 is also connected to the base of the transistor 34.
One end of the capacitor 36 is connected to the signal coil 1 through a resistor 37 and a diode 38, and the other end of the capacitor 36 is connected to the signal coil 1 through a resistor 37 and a diode 38.
Connected to one end of 2. The emitter of transistor 34 is connected to the anode of diode 39, and a pump-up capacitor 40 is connected between the cathode of diode 39 and ground. resistance 3
A pump circuit 41 is constituted by each of the components 1 to 40, and this pump circuit includes a transistor 34, a diode 35, and a capacitor 3.
6, a resistor 37, and a diode 38 constitute a pump-up switch circuit. When the signal Vs1 of the first polarity is generated in the signal coil 12, the signal coil 12 is connected to the diode 35 and the capacitor 3.
6, a current flows through the resistor 37 and the diode 38, and the capacitor 36 is charged. When the charging voltage of capacitor 38 reaches a predetermined value, transistor 34 becomes conductive and the charge of capacitor 32 is transferred to capacitor 40 . As a result, the capacitor 40 is instantly charged to the charging voltage of the capacitor 32 (which is constant regardless of the rotational speed).

One non-grounded end of the integrating capacitor 28 of the integrating circuit 30 and one non-grounded end of the pump up capacitor 40 of the pump circuit 41 are connected to the anodes of diodes 60 and 61, respectively, and the cathodes of both diodes are commonly connected. and is connected to the collector of a transistor 62 whose emitter is grounded. The base of the transistor 62 is connected to a voltage dividing point of a voltage dividing circuit consisting of a series circuit of resistors 63 and 64 connected in parallel to both ends of the signal coil 12, and diodes 60 and 61, and a transistor 6.
2 and resistors 63 and 64, the reset circuit 6
5 are configured. In this reset circuit, when the signal Vs2 of the second polarity is generated in the signal coil 12, the transistor 62 becomes conductive, and the transistor instantly discharges the capacitors 28 and 40.

In this way, since the integrating capacitor 28 is reset by the signal Vs2 of the second polarity, the voltage V28 obtained across the integrating capacitor 28 is as shown in FIG.
As shown in , from the generation position θi2 of each second polarity signal Vs2 to the generation position θi2 of the next second polarity signal Vs2
It becomes a triangular wave voltage that rises at a constant slope until (during 360 degrees). Engine speed (rpm) is N1, N2
(>N1), the waveform of the triangular wave voltage V28 with respect to the rotation angle is as shown by the chain line in FIG. 2C, and the slope of the triangular wave voltage becomes smaller as the rotational speed increases. Furthermore, since the pump-up capacitor 40 is also instantaneously discharged through the reset circuit by the second polarity signal Vs2, the waveform of the terminal voltage V40 of the capacitor 40 has a peak value as shown by the solid line in FIG. 2C. It becomes a constant square wave voltage regardless of the rotation speed.

The terminal voltages V28 and V40 of the capacitors 28 and 40 are input to a comparison circuit 70 and compared.
The comparison circuit 70 of this embodiment has a transistor 71
, a capacitor 72 and a resistor 73 connected in parallel between the collector of the transistor 71 and the ground, the collector of the transistor 71 is connected to the non-grounded terminal of the capacitor 40, and the base is connected to the non-grounded terminal of the capacitor 28. are connected to each. In this comparison circuit 70, the capacitor 4
When the rectangular wave voltage V40 obtained across the capacitor 28 is less than the triangular wave voltage V28 obtained across the capacitor 28, the transistor 71 is in a cut-off state and the rectangular wave voltage
When V40 exceeds the triangular wave voltage V28, the transistor 71 becomes conductive and discharges the charge in the capacitor 40. Therefore, as shown in FIG. 2C, when the engine speed reaches N2 and the rectangular wave voltage V40 exceeds the triangular wave voltage V28, a voltage is applied across the resistor 73 connected to the emitter of the transistor 71 as shown in FIG. 2D. A pulsed signal voltage V73 is obtained.

The non-grounded terminal of the resistor 73 of the comparison circuit 70 (the output terminal of the comparison circuit) is connected to the base of a transistor 80, and the collector of the transistor 80 is connected to the cathode of the Zener diode 23. Further, the emitter of the transistor 80 is connected to the anode of a diode 81, and the cathode of the diode 81 is connected to the gate of the thyristor 4. A trigger circuit 82 is configured by a transistor 80 and a diode 81. In this trigger circuit, when the pulse signal V73 is applied from the comparator circuit 70, the transistor 80 becomes conductive, and an ignition signal is applied from the capacitor 22 side to the thyristor 4, thereby making the thyristor conductive and performing an ignition operation.

In this embodiment, a second signal supply circuit is constituted by the integration circuit 30, the pump circuit 41, the reset circuit 65, the comparison circuit 70, and the trigger circuit 82; , a first comprising the signal coil 12 and the diode 11.
An ignition timing determination circuit is constituted by the signal supply circuit and the signal supply circuit.

In the above embodiment, when the engine speed N is less than the set speed, for example, when N=N1,
A square wave voltage is applied across capacitor 40 in FIG.
Since the triangular wave voltage V28 obtained across the capacitor 28 when V40 occurs is higher than the rectangular wave voltage V40, the transistor 71 of the comparison circuit 71 is not conductive, and the pulse signal voltage is applied across the resistor 73.
V73 does not occur. At this time, an ignition signal is supplied to the thyristor 4 through the diode 11 by the second polarity signal Vs2 obtained from the signal coil 12, and ignition is performed at the generation position θi2 of the second polarity signal. In contrast, the engine speed is set to
When N2 is reached, the rectangular wave voltage V40 exceeds the triangular wave voltage V28 at the rise as shown in FIG. A base current is supplied to the transistor 80 of the trigger circuit 82 by the pulse signal. As a result, an ignition signal is supplied to the thyristor 4, and an ignition operation is performed. Therefore, when the engine speed reaches the set value,
The ignition operation is performed at the rising position of the square wave voltage V40 (first
As shown in FIG. 3, the ignition timing θi is advanced in steps from θi2 to θi1.

Note that FIG. 2H shows the high voltage Vh for ignition generated in the secondary coil of the ignition coil 1 at angles θi1 and θi2, respectively.

In the above embodiment, a capacitor discharge type circuit is used as the ignition circuit, but the ignition circuit used in the present invention is a primary current control semiconductor whose operation timing is determined by giving an ignition signal by the output of a signal coil. Any circuit that controls the primary current of the ignition coil using a switch and obtains high voltage for ignition is sufficient.
This is a well-known method that suddenly changes the primary current of the ignition coil to perform ignition by cutting off the current flowing in the primary circuit of the ignition coil by operating a semiconductor switch for primary current control at the ignition timing of the engine. Of course, the present invention can also be applied when a current interrupt type ignition circuit is used.

In the above embodiment, a constant current circuit consisting of the transistor 26 and the resistors 24, 25, and 27 was provided in the integrating circuit 30 to charge the capacitor 28 with a constant current, but as shown in FIG. 4A, Alternatively, the integrating capacitor 28 may be simply charged with the voltage across the Zener diode 23 through the resistor 27. In this case, the voltage across the integrating capacitor 28 is
The waveform of V28 is a slightly curved triangular waveform as shown in FIG. 4C. The triangular waveform referred to in the present invention also includes the waveform shown in FIG. 4C.

In the embodiment shown in FIG. 1, the pump power supply capacitor 32 is connected to the resistor 3 by the output of the exciter coil 6.
1, but as shown in FIG.
The capacitor 32 may be charged with a voltage obtained by dividing the voltage using a voltage dividing circuit including 42 series circuits. In this way, the capacitor 32
Also, the withstand voltage of the parts of the pump circuit connected to the capacitor can be lowered.

[Effects of the Invention] As described above, in the present invention, among the first and second polarity signals generated from the signal coil, the next second polarity signal is detected from the generation position of the second polarity signal generated later. An integrating capacitor that is charged at a constant time constant until the position where a signal of the first polarity is generated and a pump-up capacitor that is instantly charged at a constant voltage at the position where a signal of the first polarity is generated are provided. The triangular wave voltage obtained at both ends of the pump-up capacitor is compared with the rectangular wave voltage obtained across the pump-up capacitor, and when the rectangular wave voltage is below the triangular wave voltage, an ignition signal is given by the signal of the second polarity, and when the rectangular wave voltage rises, the ignition signal is applied. Since the ignition signal is given at the position where the first polarity signal is generated when the triangular wave voltage is exceeded, the set rotation speed is accurately detected without being affected by the output waveform of the exciter coil, and the advance angle is determined. can be made to perform an action. In addition, the power for the integrating circuit and pump circuit is supplied from the exciter coil, and the output of the signal coil is used only for signals, so even if the output of the signal coil is small, it can operate sufficiently, and the signal generator used Miniaturization can be achieved. Further, the set rotational speed at which the advance angle operation is performed can be easily set to an appropriate value by appropriately setting the charging time constant of the integrating capacitor, which facilitates circuit design.

[Brief explanation of drawings]

Fig. 1 is a circuit diagram showing one embodiment of the present invention, Fig. 2 is a waveform diagram showing the operating waveforms of each part of Fig. 1 with respect to the rotation angle of the engine, and Fig. 3 is a waveform diagram showing the operating waveforms of each part in Fig. 1 with respect to the rotation angle of the engine. FIG. 4A is a connection diagram showing a modified example of the integrating circuit used in the present invention, and FIGS. 4B and C are graphs showing the signal voltage obtained in the signal coil and A waveform diagram showing the triangular wave voltage obtained in the circuit, and FIG. 5 is a connection diagram showing the main parts of a modified example of the pump circuit used in the present invention. 1...Ignition coil, 2...Spark plug, 3...
Capacitor, 4... Thyristor (semiconductor switch for primary current control), 5... Diode, 6... Exciter coil, 10... Ignition circuit, 12... Signal coil, 20... Diode, 21... Resistor,
22... Power supply capacitor, 24, 25, 27...
Resistor, 26... Transistor, 28... Integrating capacitor, 30... Integrating circuit, 31... Resistor, 32
... Pump power supply capacitor, 33 ... Zener diode, 34 ... Transistor, 40 ... Pump up capacitor, 62 ... Transistor, 6
5...Reset circuit, 70...Comparison circuit, 71...
...Transistor, 73...Resistor, 80...Transistor, 81...Diode, 82...Trigger circuit.

Claims (1)

[Claims] 1. An exciter coil that induces an alternating current voltage in synchronization with the rotation of an internal combustion engine is used as an ignition power source, and a semiconductor switch that operates when an ignition signal is applied to a control signal input terminal controls the primary current of the ignition coil. Inputs the output of an ignition circuit that controls the ignition operation and a signal coil that sequentially induces a first polarity signal and a second polarity signal at predetermined angular intervals in synchronization with the rotation of the internal combustion engine. and an ignition timing determination circuit that supplies the ignition signal to the primary current control semiconductor switch to determine the ignition timing, wherein the ignition timing determination circuit includes a signal generated from the signal coil. A first supplying the ignition signal to the primary current control semiconductor switch with a signal of the second polarity generated from the second polarity of the signal.
and a second signal supply circuit that supplies the ignition signal to the primary current control semiconductor switch when the first polarity signal whose phase is ahead of the second signal is generated. The second signal supply circuit includes: an integrating circuit having an integrating capacitor and a capacitor charging circuit that charges the integrating capacitor to one polarity with a constant time constant using the output of the exciter coil; and the output of the exciter coil. a pump power supply capacitor which is charged with a constant voltage to one polarity in
a pump circuit including a pump-up switch circuit that conducts when triggered by a signal of the second polarity, and a pump-up capacitor that is charged through the pump-up switch circuit with the charge of the pump power supply capacitor; and a pump circuit that generates the signal of the second polarity. a reset circuit that instantaneously discharges the integrating capacitor and the pump-up capacitor when the pump-up capacitor is turned on; a comparison circuit that compares the triangular wave voltage obtained across the integrating capacitor with the rectangular wave voltage obtained across the pump-up capacitor; a trigger circuit that is controlled by the output of the comparator circuit and supplies the ignition signal to the primary current control semiconductor switch when the rectangular wave voltage exceeds the triangular wave voltage at the time of rising; An ignition device for an internal combustion engine, characterized in that a charging time constant of the integral capacitor is set so that the rectangular wave voltage exceeds the triangular wave voltage at the time of rising when the voltage exceeds a set value.