Capacitor discharge type ignition device for internal combustion engine

The present invention relates to a capacitor discharge type ignition device for an internal combustion engine.

[0002] A condenser discharge type ignition device for an internal combustion engine includes an ignition coil and an ignition capacitor provided on the primary side of the ignition coil and charged to one polarity by an output voltage of a predetermined power source. , A discharge thyristor that conducts when an ignition signal is given and discharges the charge of the ignition capacitor through the primary coil of the ignition coil, a signal generator that generates a signal for obtaining rotation information of the internal combustion engine, and a signal generator. It is composed of an ignition control unit that gives an ignition signal to the discharge thylister at the ignition position of the internal combustion engine (the rotation angle position of the crank shaft when the ignition operation is performed) determined based on the rotation information obtained from the signal generated by the unit. Will be done.

[0003] As a power source for charging the ignition capacitor, an exciter coil provided in a magneto generator driven by an internal combustion engine and inducing an AC voltage in synchronization with the rotation of the engine is often used.

[0004] Recently, in order to purify the exhaust gas of an engine and improve fuel efficiency, it is required to give the engine a complicated ignition characteristic. Therefore, in many cases, a microcomputer is provided in the ignition control unit to determine the ignition position by software.

[0005] When the ignition signal is generated at the ignition position determined by software using a microcomputer, the reference position is set to a position sufficiently advanced from the rotation angle position corresponding to the top dead center of the internal combustion engine. The time required for the engine to rotate from the reference position to the calculated ignition position is calculated as the ignition timer time, and when the reference position is detected, the ignition timer starts measuring the ignition timer time. Then, when the measurement is completed, an ignition signal is generated.

[0006] As described above, in the ignition device for an internal combustion engine that controls the top position using a microcomputer, the reference position as a reference when measuring the ignition position determined by software, and at the time of starting and at extremely low speed. Since it is necessary to detect the ignition position of the engine, the signal generator sets the reference position detection signal at a reference position set at a position sufficiently advanced from the rotation angle position of the crankshaft corresponding to the top dead center of the engine. Is configured to generate an extremely low speed point fire position detection signal at a position suitable as an ignition position at the time of starting the internal combustion engine and at an extremely low speed.

[0007] Further, the ignition control unit includes an extremely low speed time point fire control unit that gives an ignition signal to the discharge thyristor when an extremely low speed time point fire position detection signal is generated, and an internal combustion engine obtained from the output signal of the signal generation unit. A steady-time fire control unit that gives an ignition signal to the discharge thyristor at the ignition position determined based on the rotation information is provided.

[0008] When determining the ignition position using a microcomputer, if a battery is provided, the microcomputer can be operated from the start of the engine, so that there is no problem. However, if the battery is not installed, or if it is necessary to enable the operation of the engine even when the battery is exhausted for safety reasons such as an outboard motor, the output of the generator attached to the engine can be used. It is necessary to give the power supply voltage to the microcomputer. Therefore, in this type of ignition device, a control power supply circuit that rectifies the negative half-wave output of the exciter coil that is not used for charging the ignition capacitor to generate a constant DC voltage is provided, and ignition is performed from this power supply circuit. The power supply voltage is applied to the control unit.

[0009] In a batteryless igniter in which a power supply voltage is applied to a microcomputer by the output of a control power supply circuit using a generator attached to an internal combustion engine as a power source without using a battery, when the engine is started, Since the microcomputer cannot be operated normally until the output voltage of the generator rises to some extent, the ignition operation cannot be performed while the rotation speed of the internal combustion engine is low. Even if the microcomputer can be operated normally, the ignition position calculated by the microcomputer can be accurately calculated because the rotation speed fluctuates greatly due to the change in the engine stroke while the rotation speed of the engine is low. It becomes difficult to measure, and it is difficult to make the ignition operation stable.

[0010] Therefore, in the batteryless ignition device, a signal is generated from a generator or a signal generator attached to the engine at an appropriate position as an ignition position at the time of starting the engine and at an extremely low speed, and this signal is generated. By giving an ignition signal to the discharge thyristor in terms of hardware at the time of occurrence, stable ignition is performed at the time of starting and at extremely low speed (speed range below the idling rotation speed).

[0011] As described above, in a battery-less condenser discharge ignition device in which an ignition position is determined by software using a microcomputer, the engine is started and the speed is extremely low. In order to stabilize the ignition at the time, an extremely low-speed point-in-time fire control unit that generates an ignition signal in hardware is provided, but in the conventional ignition device of this type, a steady-time point-of-time fire control equipped with a microcomputer Since the power supply voltage is applied from the same power supply circuit to the unit and the extremely low speed point fire control unit, there is a problem that the operation of the extremely low speed time point fire control unit is delayed when the engine is started.

[0012] That is, when the rotation speed of the engine is low and the peak value of the output voltage of the negative half wave of the exciter coil is not sufficiently high because the microcomputer constantly consumes power (the negative half wave of the exciter coil). When the peak of the output voltage is barely reaching the power supply voltage of the microcomputer), the power supply circuit operates the microcomputer while the exciter coil is generating a negative half-wave output voltage. Even if a voltage of a required value (5V) is output, the output of the control power supply circuit stops when the exciter coil outputs a positive half-wave voltage. Therefore, it waited until the rotation speed of the engine further increased and the output voltage of the exciter coil increased until the control power supply circuit for driving the microcomputer stably output the voltage maintained at the set value. There must be. Therefore, when the power supply voltage is applied to the extremely low speed point fire control unit with the same power supply circuit as the power supply circuit that drives the microcomputer, the start of operation of the extremely low speed time point fire control unit is delayed, and the engine startability. There was a problem that the ignition operation became unstable at the time of idling.

[0013] An object of the present invention is to sufficiently reduce the rotation speed at which the extremely low speed point-in-time fire control unit starts operation, improve the startability of the internal combustion engine, and enable stable idling rotation. It is an object of the present invention to provide an ignition device for a condenser discharge type internal combustion engine.

[Means for Solving the Problems] The present invention relates to an exciter coil provided in a magnet generator driven by an internal combustion engine, an ignition coil, and an exciter coil provided on the primary side of the ignition coil. An ignition capacitor that is charged to one polarity with a positive half-wave output voltage, and a discharge thyristor that conducts when an ignition signal is given and discharges the charge of the ignition capacitor through the primary coil of the ignition coil. The reference position is detected by the control power supply circuit that converts the output voltage of the exciter coil into a DC voltage and the reference position set at a position sufficiently advanced from the rotation angle position of the crank shaft corresponding to the top dead point of the internal combustion engine. A signal generator that generates a signal and generates an extremely low speed time point fire position detection signal at a position suitable as an ignition position when starting an internal combustion engine and at an extremely low speed, and a discharge unit when an extremely low speed time point fire position detection signal is generated. Ignition position determined based on the rotation information of the internal combustion engine obtained from the output signal of the extremely low-speed point-in-time fire control unit that gives an ignition signal to the thyristor and the signal generation unit.<u style="single">Is started when the reference position detection signal is generated, and when the measurement of the ignition position is completed.</u>The discharge thyristor is provided with a steady time point fire control unit that gives an ignition signal, and the extremely low speed time point fire control unit and the steady time point fire control unit are configured to operate using the DC voltage obtained from the control power supply circuit as the power supply voltage. The target is a condenser discharge type ignition device for an internal combustion engine.

[0015] In the present invention, the first control power supply circuit generates a constant DC voltage for operating the steady-time fire control unit when the output voltage of the exciter coil is equal to or higher than a set value. A power supply circuit and a second power supply circuit that generates a DC voltage for operating the extremely low speed point-in-time fire control unit from the state where the output voltage of the exciter coil is less than the set value are provided.

[0016] Further, the extremely low speed point fire control unit is configured to start operation at a power supply voltage lower than the power supply voltage (usually 5V) of the steady state time point fire control unit.

[0017] Since the extremely low speed point-in-time fire control unit consumes electric power only for a short period of time when the ignition signal at extremely low speed is generated, the rotation speed of the engine is low, and the exciter coil is transmitted from the first power supply circuit. Even when the output required for stable operation of the constant ignition control unit cannot be generated, the power supply voltage required for stable operation of the extremely low speed point-in-time fire control unit is stably generated from the second power supply circuit. Can be made to. Therefore, as described above, if a second power supply circuit dedicated to the extremely low speed point fire control unit is provided, the extremely low speed time point fire control unit has a rotation speed lower than the rotation speed at which the steady time point fire control unit starts operation. The operation of the engine can be started, the startability of the engine can be improved, and the idling rotation can be stably performed.

[0018] The magnet generator used to operate the condenser discharge type ignition device for an internal combustion engine includes a rotating body attached to the crank shaft of the internal combustion engine and one permanent magnet attached to the outer periphery of the rotating body. A magnet rotor having a three-pole magnet field formed by the permanent magnet and the outer peripheral portion of the rotating body adjacent to the permanent magnet, and a magnetic pole portion facing the magnet field of the magnet rotor. The first negative half-wave voltage, the positive half-wave voltage, and the second negative half during one rotation of the magnet rotor having the iron core having the iron core and the exciter coil wound around the iron core. In many cases, a magnet consisting of a stator that outputs an AC voltage for one and a half cycles in which the wave voltage appears in sequence from the exciter coil is used.

[0019] When such a magnet generator is used, the signal generator is formed into a rectangular shape by waveform-shaping the exciter coil and the first and second negative half-wave voltages output by the exciter coil, respectively. It can be configured by a waveform shaping circuit that converts into wavy first and second pulse signals.

[0020] In this case, the magneto generator so that the position of the rising edge or the position of the falling edge of the second pulse signal coincides with a position suitable as an ignition position at the start of the internal combustion engine and at extremely low speed. It is provided in.

[0021] Further, the extremely low speed time point fire control unit uses the rising edge or the falling edge of the first and second pulse signals as the extremely low speed time point fire position detection signal, and sets the rising edge of the first pulse signal. Alternatively, the ignition signal is supplied to the discharge thyristor at the position where the falling edge occurs and the position where the rising or falling edge of the second pulse signal occurs. This extremely low speed point fire control unit is configured by a hardware circuit.

Further, the stationary point-in-time fire control unit operates with the rising edge or falling edge of the first pulse signal as the reference position detection signal and the DC voltage obtained from the first power supply circuit as the power supply voltage. The ignition position is calculated at each rotation speed of the engine and the calculated ignition position is detected, and an ignition signal is given to the discharge thyristor when the calculated ignition position is detected.

[0023] With the above configuration, the ignition signal is given to the discharge thyristor even before the exciter coil generates a positive half-wave output voltage (before the ignition capacitor is charged), but for ignition. Even if an ignition signal is given while the capacitor is not charged, the discharge thyristor does not conduct and the ignition operation is not performed, so that the ignition of the engine is not hindered.

[0024] With the above configuration, it is not necessary to provide a signal generator separately from the magneto generator, so that the ignition position can be determined by calculation without complicating the configuration of the engine. , It is possible to obtain an ignition device for an internal combustion engine that can correspond to various ignition characteristics.

[0025] In the present specification, the ignition signal given to the discharge thyristor from the extremely low speed point-in-time fire control unit including the hardware circuit is referred to as a "hard ignition signal" in the sense of the ignition signal given from the hardware circuit. The ignition operation performed by this hard ignition signal is called hard ignition.

[0026] On the other hand, "soft" means an ignition signal generated at an ignition position determined by software to give an ignition signal to the discharge thyristor at the ignition position calculated by causing the microcomputer to execute predetermined software. It is called "ignition signal". The ignition operation performed by this soft ignition signal is called soft ignition.

[0027] In a preferred embodiment of the present invention, for canceling an ignition signal that conducts when a cancel command is given and transmits an ignition signal given to the discharge thyristor from the extremely low speed point-in-time fire control unit from the discharge thyristor. Further switches are provided. In this case, the microcomputer of the stationary time point fire control unit calculates the first pulse signal and the second pulse signal from the signal width of the first and second pulse signals and the generation interval of the first and second pulse signals. The rotation speed of the internal combustion engine is detected by using a reference position detecting means for detecting the rising or falling edge of one of the determined pulse signals as a reference position and at least one of the first and second pulse signals. Rotation speed detection means for obtaining data for the purpose, and ignition position calculation means for calculating the ignition position of the internal combustion engine with respect to the detected rotation speed in the form of the time required for the crank shaft of the engine to rotate from the reference position to the ignition position. Then, when the reference position is detected, the measurement of the ignition position is started, and when the measurement of the ignition position is completed, the ignition position detecting means for giving an ignition signal to the discharge thylister and the rotation speed of the internal combustion engine are set. It is programmed to configure a cancel command generating means that generates a cancel command when the value is exceeded.

[0028] When the cancel switch is provided as described above and the rotation speed of the engine exceeds the set value and the microcomputer is in the operating state, the cancel switch is made conductive and discharged from the extremely low speed point-in-time fire control unit. If the ignition signal given to the discharge thyristor is sideways from the discharge thyristor, the discharge thyristor will be generated by the ignition signal given to the discharge thyristor at the falling or rising of the first pulse signal during steady operation. It is possible to prevent the engine from misfiring due to a state in which the ignition capacitor is not charged due to conduction.

[0029] The ultra-low speed point-in-time fire control unit includes an ignition signal supply capacitor that is charged by the output voltage of the second power supply circuit between the current limiting element and the gate cathode of the discharge thylister, and the first and second capacitors. A transistor provided so as to conduct the pulse signal as a base signal and side-pass the charging current of the ignition signal supply capacitor from the capacitor, and discharge the charge of the ignition signal supply capacitor through the transistor when the transistor conducts. It is provided with a capacitor that couples between the ignition signal supply capacitor and the transistor so that the ignition signal is given to the discharge thylister at the falling edge of the first pulse signal and the second pulse signal. can do.

[0030] In the above example, the negative half-wave output voltage of the exciter coil is shaped into a pulse waveform to obtain a reference position detection signal and an extremely low speed time point fire position detection signal. A reference position detection signal and an extremely low speed time point fire position detection signal may be obtained from the output of the generator. In this case, the signal generator is attached to the internal combustion engine and generates the first signal when the rotation angle position of the crank shaft of the engine matches the reference position, and the rotation angle position of the internal combustion engine is at the start and at the pole. A signal generator that generates a second signal when it matches a position suitable as an ignition position at low speed, and a reference that shapes the first and second signals output by the signal generator into predetermined waveforms, respectively. It can be configured by a waveform shaping circuit that outputs as a position detection signal and an extremely low speed time point fire position detection signal.

[Embodiment] In the present invention, the ignition capacitor is charged by the output of an exciter coil provided in a magneto generator driven by an internal combustion engine. As the magneto generator used for the ignition device for an internal combustion engine, the one shown in FIG. 4 is often used. This magnet generator was mounted in a cup-shaped rotating body 2 attached to the crank shaft 1 of the internal combustion engine and a recess 2a provided on the outer periphery of the rotating body, and was magnetized in the radial direction of the rotating body. A magnet rotor 4 having one permanent magnet 3 and forming a three-pole magnet field magnet by the permanent magnet 3 and the outer peripheral portion of a rotating body 2 adjacent to the permanent magnet, and a magnet of the magnet rotor 4 It is composed of a stator 7 formed by winding an exciter coil 6 around a U-shaped iron core 5 having magnetic pole portions 5a and 5b facing a field magnet. In the illustrated example, the outer magnetic pole of the magnet 3 is the N pole, so one N pole and two S poles formed on the outer periphery of the rotating body on both sides of the N pole create a three-pole magnet field. It is configured. The stator 7 is fixed to a stator mounting portion provided on an engine case, cover, or the like, and the magnetic pole portions 5a and 5b of the iron core 5 face the magnet field of the magnet rotor 4 via an air gap. Be done.

[0032] In this generator, the first negative half-wave voltage Vn1 and the positive half-wave voltage Vp, as shown in FIG. 4 (B), while the magnet rotor 4 makes one rotation with the crankshaft. The AC voltage Ve for one and a half cycles in which the second negative half-wave voltage Vn2 appears in sequence is output from the exciter coil 6.

When the generator shown in FIG. 4 is used, the positive half-wave voltage Vp output by the exciter coil 6 is used as the voltage for charging the ignition capacitor.

[0034] FIG. 1 shows an example of hardware configuration of an ignition device for a capacitor discharge type internal combustion engine according to the present invention. In the figure, 6 is an exciter coil provided in the magneto generator shown in FIG. 4, and IG is an ignition coil having a primary coil W1 and a secondary coil W2. One end of the primary coil and the secondary coil of the ignition coil IG was grounded, and the other end of the primary coil W1 and the other end of the secondary coil W2 were attached to one end of the ignition capacitor Ci and the cylinder of an engine (not shown), respectively. It is connected to the non-grounded terminal of the spark plug PL.

The exciter coil 6 has a positive first negative half-wave voltage Vn1 while the magnet rotor 4 (see FIG. 4A) makes one revolution with the crankshaft 1, as shown in FIG. 4 (B). Outputs an AC voltage Ve for one and a half cycles in which the half-wave voltage Vp and the second negative half-wave voltage Vn2 appear in sequence. Note that θ on the horizontal axis in FIG. 4B indicates the rotation angle of the crankshaft.

The other end of the ignition capacitor Ci is connected to the anode of the discharge thyristor Thi with the cathode grounded, and is connected to one end of the exciter coil 6 through a diode D1 having the cathode directed toward the ignition capacitor. There is. The other end of the exciter coil 6 is connected to the cathode of the diode D2 whose anode is grounded, and the diode D3 whose anode is directed to the ground side is connected between one end of the exciter coil 6 and the ground.

In the illustrated example, the ignition coil IG, the ignition capacitor Ci, and the discharge thyristor Thi constitute an ignition circuit that forms a main part of the ignition device. The exciter coil 6 and the diodes D1 to D3 form the charging power supply of the ignition capacitor Ci.

[0038] In the illustrated ignition circuit, the positive half-wave output voltage of the exciter coil 6 charges the ignition capacitor Ci to the indicated polarity through the diode D1. When the discharge thyristor Thi is given an ignition signal Vi from the circuit described later while the capacitor Ci is charged to the indicated polarity (a forward voltage is applied between the anode and cathode of the thyristor Thi), the discharge is performed. Since the thyristor for ignition is conducting, the charge of the ignition capacitor Ci is discharged through the thyristor for discharge Thi and the primary coil W1 of the ignition coil IG. As a result, a high voltage for ignition is induced in the secondary coil of the ignition coil IG, and this high voltage is applied to the spark plug PL, so that sparks are generated at the spark plug and the engine is ignited.

[0039] Although protective resistors and capacitors are connected between the gate cathode and the anode cathode of the thyristor Thi, their illustrations are omitted.

[0040] In the present invention, one end of the resistor R1 is connected to the other end of the exciter coil 6 through a diode D10 having the anode directed toward the exciter coil 6, and the first end between the other end of the resistor R1 and the ground. Power supply capacitor C1 is connected. A Zener diode ZD1 with its anode facing the ground is connected to both ends of the capacitor C1, and the Zener diode keeps the voltage across the capacitor C1 below a certain value (Zener voltage). The voltage across the capacitor C1 is input to the 3-terminal regulator Reg, which has the function of controlling the output voltage to remain constant (5 [V] in this example) with respect to fluctuations in the input voltage. The diode D10, the resistor R1, the first power supply capacitor C1, the Zener diode ZD1, and the 3-terminal regulator Reg generate the first and second negative half-wave voltages Vn1 and Vn2 output by the exciter coil. A first power supply circuit 10A that converts to a DC voltage for control is configured, and the output terminal of the regulator Reg is the output terminal 10a of this power supply circuit 10A.

[0041] Further, one end of the resistor R1'is connected to the other end of the exciter coil 6 through a diode D10'with the anode facing the exciter coil side, and a second power supply capacitor C1'between the other end of the resistor and the ground. Is connected. A Zener diode ZD1'with the anode facing the ground side is connected in parallel to both ends of the second power supply capacitor C1'. A second power supply circuit 10B is composed of a diode D1', a resistor R1', a second power supply capacitor C1', and a Zener diode ZD1', and the non-grounded side terminal of the capacitor C1'is ungrounded. The output terminal 10b of is derived.

[0042] This second power supply circuit 10B generates a DC voltage limited to the Zener voltage or less of the Zener diode ZD1'at both ends of the capacitor C1'. The Zener voltage of the Zener diode DZ1'is set lower than the control voltage of the regulator Reg.

[0043] In this example, the control power supply circuit 10 is configured by the first power supply circuit 10A and the second power supply circuit 10B.

[0044] The waveform of a series of voltage Ve output by the exciter coil 6 after the engine start operation is performed and the waveform of the voltage Vc1 across the power supply capacitor C1 of the first power supply circuit 10A are shown in FIGS. 7 (A) and 7 (A), respectively. Shown in (B). As shown in Fig. 7 (B), the terminal voltage Vc1 of the power supply capacitor C1 increases as the rotation speed of the engine increases. When the rotation speed rises to some extent and the voltage Vc1 becomes 5 [V] or more, which is the control voltage of the regulator Reg, the DC voltage Vdc with the regulator Reg constant (= 5 [V]) is set as shown in Fig. 7 (C). Output.

[0045] In FIG. 7B, Vz is the Zener voltage of the Zener diode ZD1, and the terminal voltage of the capacitor C1 is limited to this Zener voltage Vz or less.

[0046] Fig. 7 (H) shows the voltage Vci across the ignition capacitor Ci charged by the positive half-wave output voltage Vp of the exciter coil 6. The ignition capacitor Ci is charged during the peak after the positive half-wave voltage Vp rises, and its terminal voltage Vci rises.

In FIG. 1, 11 converts the first and second negative half-wave voltages Vn1 and Vn2 output by the exciter coil 6 into rectangular wavy first and second pulse signals by waveform shaping, respectively. It is a waveform shaping circuit. The illustrated waveform shaping circuit 11 includes a capacitor C2 whose one end is connected to the other end of the exciter coil 6, a resistor R2 which is connected in parallel to the capacitor C2 and has a sufficiently large resistance value, and the other end of the capacitor C2. A diode D5 with an anode connected, a resistor R3 with one end connected to the cathode of the diode D5, an NPN transistor TR1 with a base connected to the other end of the resistor R3 and a grounded emitter, and a transistor TR1 with a base. Consists of an NPN transistor TR2 connected to the collector and grounded emitter, and resistors R4 and R5 connected between the collectors of transistors TR1 and TR2 and the output terminal 10a of the first power supply circuit 10A, respectively. There is.

[0048] In this waveform shaping circuit 11, the first and second output terminals 11a and 11b are derived from the connection point between the base of the transistor TR1 and the resistor R3 and the collector of the transistor TR2, respectively.

As shown below, the waveform shaping circuit 11 detects the zeros and peaks on the rising sides of the negative half-wave voltages Vn1 and Vn2 of the exciter coil 6, respectively, and detects the zeros and peaks of FIGS. 5B and 5B. As shown in 7 (D), a rectangular wavy pulse signal is generated, which rises at the zero point on the rising side of each negative half-wave voltage and falls at the peak point. The first and second pulse signals Vq1 (or Vq1 ́) are obtained by waveform-shaping the first negative half-wave voltage Vn1 and the second negative half-wave voltage Vn2, respectively. And Vq2 (or Vq2 ́).

That is, as shown in FIGS. 5 (A) and 7 (A), when the exciter coil 6 generates a negative half-wave voltage Vn1 or Vn2, the capacitor C2, the diode D5, the resistor R3, and the transistor TR1 Current flows between the base and emitter of the. As a result, the transistor TR1 becomes conductive and the transistor TR2 is cut off. At this time, since the potential of the base of the transistor TR1 and the potential of the collector of the transistor TR2 rise, the potentials of the output terminals 11a and 11b rise to a high level, as shown in FIGS. 5 (B) and 7 (D). , Pulse signal Vq1 or Vq2 rises. When the negative half-wave voltage Vn1 or Vn2 reaches its peak, the charging current does not flow through the capacitor C2, so the transistor TR1 is cut off and the transistor TR2 becomes conductive. As a result, the potentials of the output terminals 11a and 11b drop to almost zero level (ground potential).

Therefore, when the exciter coil 6 generates the first negative half-wave voltage Vn1, the waveform shaping circuit 11 has the rising edge and the rising edge at the rising side zero point and the peak point of the voltage Vn1, respectively. When the first pulse signals Vq1 and Vq1 ́ with the same falling edge are output from the output terminals 11a and 11b and the second negative half-wave voltage Vn2 is generated, the rising side of the voltage Vn2 The second pulse signals Vq2 and Vq2 ́ whose rising edge and falling edge coincide with the zero point and the peak point are output from the output terminals 11a and 11b, respectively. Of these pulse signals, Vq1 and Vq2 are output through passive elements, so they occur when the exciter coil generates a negative half-wave voltage above the threshold immediately after the engine start operation is started. To do. Therefore, the pulse signals Vq1 and Vq2 are generated at a rotation speed sufficiently lower than the rotation speed at which the first power supply circuit 10A generates the output voltage. On the other hand, the pulse signals Vq1'and Vq2'are generated after the output voltage of the first power supply circuit 10A is established.

[0052] As described above, when a rectangular wave-shaped control signal is generated by waveform-shaping the negative half-wave voltage of a magnet generator mounted with a predetermined positional relationship with respect to the crankshaft of the engine, a pulse is generated. The rising edge positions θ11, θ21 and the falling edge positions θ12, θ22 of the signals Vq1 (or Vq1 ́), Vq2 (or Vq2 ́) correspond to specific rotation angle positions of the crankshaft.

[0053] In the present invention, the first pulse signal Vq1, Vq1 ́ and the second pulse signal Vq2, Vq2 ́ obtained by waveform-shaping the negative half-wave output voltage of the exciter coil 6 as described above. The rotation information (rotation angle position information and rotation speed information) of the internal combustion engine is obtained from the rising edge or the falling edge of the engine to determine the ignition position at the time of starting and extremely low speed, and the ignition position during steady operation. The calculation and the detection of the calculated ignition position are performed.

[0054] In order to determine the ignition position at the time of starting the engine and at extremely low speed, the position of the rising or falling edge of any of the pulse signals is set to a position suitable as the ignition position at the time of starting the engine and at extremely low speed. I will do it. The ignition position at the start of the engine and at the extremely low speed is usually a position slightly advanced from the top dead center position (the rotation angle position of the crankshaft when the piston reaches the top dead center).

[0055] In order to perform the ignition operation at the start of the engine and at extremely low speed, after the ignition capacitor Ci is charged by the positive half-wave voltage Vp of the exciter coil 6, the ignition signal Vi is sent to the discharge thyristor Thi. Need to give. Therefore, among the pulse signals, the rising edge position θ21 or the falling edge position θ22 of the second pulse signal Vq2 is made to match the ignition position at the start of the engine and at the extremely low speed.

In the example shown in FIG. 1, the magnet rotor 4 and the stator 7 are attached to the engine so that the falling edge position θ22 of the pulse signal Vq2 matches the ignition position at the start and at the extremely low speed. is there. That is, the falling edge of the pulse signal Vq2 is used as the extremely low speed time point fire position detection signal.

[0057] In order to calculate the ignition position during steady operation, data including information on the rotational speed of the engine is required. As data including information on the rotation speed of the engine, the time required for the crank shaft to rotate at a constant angle, such as the generation cycle of each pulse signal, the signal width of each pulse signal, or the generation interval of two pulse signals, is used. be able to. When calculating the ignition position, this time data may be converted into a velocity and used, or the time data itself may be used.

[0058] Further, in order to perform the ignition operation at the calculated ignition position during steady operation, it is necessary to be able to accurately detect the calculated ignition position. Therefore, the rotation angle position that is the reference of the crankshaft is set as the reference position, and the time required for the engine to rotate from the reference position to the ignition position at the calculated rotation speed (time measured by the ignition timer) Tig The ignition position is calculated in the form, and when it is detected that a reference signal has been generated, the ignition timer (timer provided in the microcomputer) is started to measure the ignition position. In the present specification, the time Tig that gives the ignition position is referred to as "ignition timer time".

[0059] The reference position may be a position whose phase is advanced by the advance angle width or more of the ignition position from the ignition position to be measured, but in order to improve the detection accuracy of the ignition position, the position is as close as possible to the ignition position. It is preferable to use the edge position of the pulse signal generated in the above as a reference position. Here, the falling edge position of the first pulse signal Vq1 ́ (same as the falling edge position of Vq1) is set as the reference position.

[0060] In this example, the reference position is set at a position sufficiently advanced from the rotation angle position of the crankshaft corresponding to the top dead center of the internal combustion engine by the exciter coil 6 and the waveform shaping circuit 11. A signal generation unit is configured to generate a detection signal and generate an extremely low speed time point fire position detection signal at a position suitable as an ignition position at the time of starting an internal combustion engine and at an extremely low speed.

[0061] The pulse signals Vq1 and Vq2 obtained from the output terminal 11a of the waveform shaping circuit 11 are applied between the base emitters of the NPN transistor TR3 whose emitter is grounded. The collector of the transistor TR3 is connected to the output terminal 10b on the non-ground side of the second power supply circuit 10B through the resistor R6, and is also connected to one end of the ignition signal supply capacitor C3, and the other end of the capacitor C3 has an anode. It is connected to the gate of the discharge thyristor Thi through the diode D6 facing the capacitor C3 side. In addition, a diode D7 with the anode grounded is connected between the other end of the capacitor C3 and the ground.

[0062] In this example, the transistor TR3, the capacitor C3, the resistor R6, and the diode D7 constitute an extremely low-speed point-in-time fire control unit 12, and the signal Vio output by this ignition control unit passes through the diode D6 to the discharge thyristor Thi. Given to the gate of.

[0063] The operation of the illustrated extremely low-speed point-in-time fire control unit 12 is as follows. When the pulse signal Vq1 or Vq2 rises and the transistor TR3 conducts, the charge stored in the capacitor C3 is instantly discharged between the collector and emitter of the transistor TR3 and the diode D7. When the pulse signal is at a high level and the transistor TR3 is conducting, the charging current of the capacitor C3 is diverted from the capacitor C3 through the transistor TR3, so that the charging of the capacitor C3 is blocked. When the pulse signal Vq1 or Vq2 given in this state falls and the transistor TR3 is cut off, the output voltage of the second power supply circuit 10B causes the resistor R6, the capacitor C3, the diode D6, and the gate of the discharge thyristor Thi. A current flows between the cathodes to charge the capacitor C3. The charging current of this capacitor C3 gives an ignition signal to the discharging thyristor Thi. The ignition signal given to the discharge thyristor from the extremely low speed point fire control unit 12 disappears when the charging of the capacitor C3 is completed and the charging current stops flowing.

[0064] The illustrated ultra-low speed point fire control unit 12 gives the discharge thyristor Thi an ignition signal Vih1 or Vih2 with a limited signal width at the falling edge of the pulse signal Vq1 or Vq2 as described above. An example of the waveforms of these ignition signals is shown in FIG. 7 (E).

[0065] The extremely low speed point-in-time fire control unit 12 gives a hard ignition signal Vih1 to the discharge thyristor Thi at the falling edge of the first pulse signal Vq1 whose phase is advanced from the positive half-wave voltage Vp of the exciter coil. When is given, the ignition operation is not performed because the ignition capacitor Ci has not been charged yet. After the exciter coil 6 generates a positive half-wave voltage Vp to charge the ignition capacitor Ci, the discharge thyristor Thi is given a hard ignition signal Vih2 at the falling edge of the second pulse signal Vq2. , The discharge thyristor Thi conducts and discharges the charge of the ignition capacitor Ci through the primary coil W1 of the ignition coil IG to perform the ignition operation.

That is, the hard ignition signal Vih1 generated at the falling edge of the pulse signal Vq1 becomes a useless signal, but has no effect on the ignition operation.

[0067] A steady-time fire control unit 13 equipped with a microcomputer 13A including a CPU, ROM, RAM, a timer, etc., in order to calculate the rotation speed, calculate the ignition position, and detect the calculated ignition position during steady operation. The first and second pulse signals Vq1 ́ and Vq2 ́ obtained from the output terminal 11b of the waveform shaping circuit 11 are input to one port A1 of the microcomputer 13A. The power supply terminal 13a of the microcomputer 13A is connected to the output terminal 10a of the first power supply circuit 10A so that the microcomputer 13A can operate when the output voltage Vdc of the first power supply circuit 10A is established. It has become.

As will be described later, the microcomputer 13A sets the recognition mode of the signal input to the port A1 into a first mode for recognizing the rising edge and a second mode for recognizing the falling edge. It is programmed to switch and recognizes the edges of the sequentially input pulse signals Vq1 ́ and Vq2 ́, which are required to obtain engine rotation information. In the present embodiment, the rising and falling edges of the pulse signal Vq1 ́ and the rising edges of the pulse signal Vq2 ́ are recognized.

[0069] When the power supply voltage of the microcomputer 13A is established and becomes operable, which of the series of pulse signals given from the waveform shaping circuit 11 is the first pulse signal, and which is the first. Performs processing to determine whether it is a pulse signal of 2. To discriminate between the first pulse signal Vq1 and the second pulse signal Vq2, the time T1 from the generation of the first pulse signal Vq1 to the generation of the second pulse signal Vq2 and the second pulse signal Vq2 are generated. It can be performed by utilizing the fact that there is a relationship of T1 &gt;&gt; T2 with T2, which is the time from that time until the next first pulse signal Vq1 is generated. For example, a pulse discrimination timer that measures the time interval between the rising edges of the pulse is provided, and as shown in FIG. 7F, the measured values of the timer are read at the rising edges of the pulse signals Vq1 and Vq2. By doing so, the times T1 and T2 are measured and stored, and when the relationship of (T1 / 2)&gt; T2 is established between the times T1 and T2, the edge when the time T1 is measured is It can be determined that it is the rising edge of the first pulse signal.

[0070] As described above, if one port recognizes the rising edge and the falling edge of the pulse signal, the pulse signals Vq1 ́ and Vq2 ́ are read from different ports and recognized. Since the number of ports required can be reduced as compared with the case, an inexpensive microcomputer can be used.

The other port A2 of the microcomputer 13A is an output port for an ignition signal, and the soft ignition signal Vis output from the port A2 passes through a diode D8 having the cathode directed toward the discharge thyristor, and the discharge thyristor is used. It is supplied to the gate of Thi as an ignition signal Vi.

In this example, the diodes D6 and D8 constitute an or circuit 14 that feeds the output of the extremely low speed point fire control unit 12 or the output of the steady state time point fire control unit 13 as an ignition signal to the gate of the discharge thyristor Thi. There is.

[0073] A cancel switch 15 is connected between the anode (non-grounded side output terminal of the extremely low speed point-in-time fire control unit 12) of one diode D6 constituting the or circuit 14 and the ground. The cancel switch 15 in the figure consists of an NPN transistor TR4 with the emitter grounded and the collector connected to the anode of diode D4, to which the cancellation command signal Vk is input from port A3 of microcomputer 13A to the base of this transistor TR4. There is.

[0074] In the microcomputer 13A, when the rotation speed of the engine exceeds the set speed, the rising edge of the first pulse signal Vq1 ́ is recognized and then the rising edge of the second pulse signal Vq2 ́ is recognized. It is programmed to configure a cancel command generating means that generates a cancel command Vk until it is recognized, and the extremely low speed point fire control unit 12 is used for starting and extremely low speed while the cancel command is being generated. When the ignition signal Vio is output, the transistor TR4 is conducted so that the ignition signal Vio is sideways from the discharge thyristor Thi.

[0075] An example of a flowchart showing an algorithm of a program executed by the microcomputer 13A in the present embodiment is shown in FIGS. 9 to 11, and a timing chart for explaining this program is shown in FIG.

FIG. 9 shows the main routine of the program executed by the microcomputer 13A, and FIG. 10 shows when the rising and falling edges of the first pulse signal Vq1 ́ are recognized, and the second pulse signal Vq2 ́. It shows the pulsed signal edge interrupt routine that is executed when the rising edge of is recognized. Further, FIG. 11 shows an ignition timer interrupt routine executed when the measurement of the set time of the ignition timer is completed.

[0077] When the power supply of the microcomputer is established, the main routine of FIG. 9 is first started. In this main routine, first, each part is initialized in step 1, then interrupt is permitted in step 2, and then the average rotation speed data of the engine is calculated in step 3. This average rotation speed data may be the time (= T1 + T2) itself required for the crankshaft of the engine to make one rotation, or may be the rotation speed calculated using this time.

[0078] After obtaining the data of the average rotation speed N in step 3, it is determined in step 4 whether or not the pulse signal edge interrupt shown in FIG. 10 is performed three or more times. As will be described later, in the present invention, in order to discriminate the pulse signals Vq1 and Vq2, it is necessary to execute the interrupt routine shown in FIG. 10 three times after the microcomputer becomes operational. In step 4 of the main routine, when the number of interrupts in FIG. 10 (the number of edge interrupts) is less than 3, it is determined that the pulse signal discrimination has not been completed, the process proceeds to step 5, and the process is canceled. Prohibit the output of signal Vk.

[0079] When it is determined in step 4 that the edge interrupt is performed three or more times, the process proceeds to step 6 to determine whether or not the average rotation speed N is equal to or higher than the soft ignition start rotation speed Ns. As a result, when it is determined that N &lt;Ns, the process proceeds to step 5 to prohibit the output of the cancel signal.

[0080] When it is determined in step 6 that N Ns, the process proceeds to step 7 to output a cancel signal Vk from port A3, and then in step 8, data (time or rotation speed) giving an average rotation speed N. The ignition position at the calculated average rotation speed is calculated by using the ignition position calculation map that gives the relationship between the ignition position and the ignition position. This ignition position is calculated in the form of an angle aimed at the advance angle side with reference to the crank angle position corresponding to the top dead center of the engine, for example.

[0081] The microcomputer 13A switches the recognition mode of the signal input to the port A1 between the first mode for recognizing the rising edge of the pulse signal and the second mode for recognizing the falling edge. However, after the microcomputer becomes operational and each part is initialized, the recognition mode of the signal input to port A1 is the first mode. Therefore, after the initialization of each part of the microcomputer is performed, the interrupt routine shown in FIG. 10 is executed when the rising edge of the pulse signal Vq1 ́ or Vq2 ́ occurs.

[0082] In this example, as shown in FIG. 8, it is assumed that the interrupt routine of FIG. 10 is executed first at the position of the crank angle θ1. In this interrupt routine, first, in step 1, it is determined whether or not the current interrupt is an interrupt due to a rising edge. Since the first pulse signal edge interrupt is an interrupt due to the rising edge, step 1 is followed by step 2. In step 2, the measured value Tx of the pulse discrimination timer (timer provided in the microcomputer) is read and stored in the memory. Next, the process proceeds to step 3 to perform pulse discrimination processing. In this pulse discrimination process, the measured value Tx-1 read and stored last time is compared with the measured value Tx read this time, and when Tx&gt; 2 × Tx-1, the pulse signal whose rising edge is recognized this time is It is determined that the first pulse signal is Vq1 ́, and when Tx Tx-1 / 2, the pulse signal for which the rising edge is recognized this time is determined to be the second pulse signal Vq2 ́.

[0083] After performing the pulse discrimination process in step 3, the process proceeds to step 4, and the pulse signal input this time is the pulse signal on the advancing side with respect to the positive half-wave output voltage Vp of the exciter coil (first). It is determined whether or not it is a pulse signal).

Since the pulse discrimination timer is not set at first, the measured value Tx of the timer read in step 2 is 0, and whether or not the pulse whose rising edge is recognized this time is the pulse on the leading side. Cannot be determined. Therefore, the process proceeds from step 4 to step 5, the pulse discrimination timer is set, the measurement of the pulse discrimination timer time Tx is started from 0, and then the process returns to the main routine.

Next, when the rising edge of the pulse signal is input to the port A1 at the position of the crank angle θ2, steps 1 and 2 of the interrupt routine shown in FIG. 10 are executed again, and the first measured pulse discrimination timer time is executed. Tx (T2 in the example shown in Figure 8) is read and stored. Next, the pulse discrimination process is performed in step 3, but at this point, since only one pulse discrimination timer time Tx has been measured, the pulse discrimination process cannot be performed at all. Therefore, in step 4, it cannot be determined that the rising edge of the pulse this time is the rising edge of the pulse signal (first pulse signal) on the advancing side, and step 5 is executed. The pulse discrimination timer is set again in step 5, and the measurement of the pulse discrimination timer time Tx is restarted.

Next, when the third pulse signal edge interrupt is executed at the position of the crank angle θ3, the pulse discrimination timer time Tx (T1 in the example shown in FIG. 8) measured in step 2 is measured last time. The pulse discrimination process can be performed from the pulse discrimination timer time Tx-1 (T2 in the illustrated example). In this pulse discrimination process (step 3), the time Tx measured this time is compared with the time Tx-1 measured last time, and the pulse in which the rising edge is recognized this time when Tx&gt; 2 × Tx-1 is recognized. The signal is determined to be the first (leading side) pulse signal Vq1 ́, and when Tx Tx-1 / 2, the pulse signal for which the rising edge is recognized this time is the second (lagging side) pulse signal. It is determined that the pulse signal is Vq2 ́. In the illustrated example, since T1&gt; 2 × T2, it is determined that the pulse signal whose rising edge is recognized this time is the first pulse signal Vq1 ́ on the leading side.

[0087] As described above, when the interrupt routine of FIG. 10 is executed three times after the microcomputer becomes operational, the pulse signals sequentially generated by the waveform shaping circuit 11 are the first and second pulse signals. You will be able to determine which of them you are.

[0088] In step 4, when it is confirmed that the pulse signal to which the rising edge is input is the pulse signal Vq1 ́ on the advancing side, the pulse discrimination timer is subsequently set in step 6. It is set and the measurement of the pulse discrimination timer time Tx is restarted, and in step 7, the instantaneous speed measurement timer (timer provided in the microcomputer) is set and the time measurement for obtaining the instantaneous speed data is started. Will be done. Then, in step 8, after inverting the signal recognition mode of port A1 so that port A1 of the CPU recognizes the falling edge of the input signal (after changing the signal recognition mode to the second mode), return to the main routine. ..

[0089] As described above, when the rising edge of the first pulse signal Vq1 ́ is recognized, the recognition mode of the signal input to the port A1 is switched to the mode of recognizing the falling edge of the signal. The interrupt routine shown in Fig. 10 is executed when the falling edge of the pulse signal Vq1 ́ of 1 is input. At this time, since it is determined in step 1 that the interrupt is due to the falling edge, step 9 is then executed to read the measurement time Tn of the instantaneous speed measurement timer set in step 7 in the previous interrupt. Next, in step 10, the instantaneous rotation speed is calculated from this measurement time Tn, and the ignition position calculated in the main routine in step 11 is converted into the ignition timer time Tig. This ignition timer time Tig is the instantaneous rotation speed calculated in step 10 from the reference position of the crankshaft (in this example, the falling position of the first pulse signal Vq1 ́) to the ignition position calculated in the main routine. It is the time required to rotate.

[0090] After calculating the ignition timer time Tig in step 11, the ignition timer time Tig is set in the ignition timer (timer in the microcomputer) in step 12, and the measurement of the ignition position is started. After that, in step 13, the ignition flag is set to "1", and in step 14, the signal recognition mode of the CPU boat A is inverted to the mode for recognizing the rise of the input signal (first mode), and then the main routine is entered. Return.

When the ignition timer completes the measurement of the ignition timer time Tig (completes the measurement of the ignition position), the ignition timer interrupt shown in FIG. 11 is executed. In this interrupt routine, first, in step 1, it is determined whether or not the ignition flag is "1", and when the ignition fluctuation is "1", the process proceeds to step 2 to start the output of the soft ignition signal. Next, in step 3, the ignition signal output stop time detection time is set in the ignition timer, and the measurement is started. Then, after setting the ignition flag to "0" in step 4, the process returns to the main routine. When the ignition timer completes the measurement of the ignition signal output stop time detection time, the ignition timer interrupt shown in FIG. 11 is executed again. At this time, since the ignition flag is "0", step 5 is executed to stop the output of the ignition signal.

[0092] In the above example, the ignition operation is performed by giving an ignition signal to the discharge thyristor from the extremely low speed point-in-time fire control unit 12 at the time of starting the engine and when the rotation speed is less than the set value Ns (soft ignition start rotation speed). After the computer 13A is in operation, when the rotation speed of the engine exceeds the set value Ns, a cancel signal Vk is generated from the computer to conduct the transistor TR4 that constitutes the cancel switch. , The hard ignition signal Vih given to the discharge thyristor Thi from the extremely low speed point-in-time fire control unit 12 is side-routed from the discharge thyristor.

[0093] With this configuration, it is possible to prevent the discharge thyristor from being given a hard ignition signal at the falling or rising edge of the first pulse signal during steady operation, so that the hard ignition signal is given during steady operation. As a result, the discharge thyristor becomes conductive and the ignition capacitor Ci cannot be charged, which eliminates the risk of engine misfire.

[0094] When the program shown in FIGS. 9 to 11 is executed by a microcomputer, the signal widths of the first and second pulse signals and the signal widths of the first and second pulse signals are determined by steps 1 to 5 in FIG. A reference position detecting means for detecting the position of the rising or falling edge of one of the pulse signals, which is determined by discriminating the first pulse signal and the second pulse signal from the generation interval, is configured as a reference position.

Further, in step 3 of the main routine of FIG. 9, the crankshaft is set to 1 after the rising edge position or the falling edge position (the rising edge position in the above embodiment) of the first pulse signal is detected. An average speed detecting means for obtaining the elapsed time until the same position after rotation is detected as data for detecting the average rotation speed of the internal combustion engine is configured.

Further, according to steps 7 and 8 of the interrupt routine of FIG. 10, when the rising edge of the first pulse signal is recognized, the time counting for instantaneous speed measurement is started, and the signal input to the port A1 is started. An instantaneous speed measurement starting means for switching the recognition mode to the second mode is configured, and steps 9 and 10 of the interrupt routine in FIG. 10 indicate a fall from the time when the rising edge of the first pulse signal is recognized. An instantaneous speed detecting means for obtaining the time measured up to the time when the edge is recognized as data for detecting the instantaneous rotation speed of the internal combustion engine is configured.

[0097] The average speed detecting means and the instantaneous speed detecting means constitute a rotation speed detecting means for obtaining data for detecting the rotation speed of the internal combustion engine using at least one of the first and second pulse signals. There is.

[0098] Further, according to step 8 of the main routine shown in FIG. 9 and step 11 of the interrupt routine of FIG. 10, the crankshaft of the engine changes the ignition position of the internal combustion engine with respect to the detected rotation speed from the reference position to the ignition position. An ignition position calculation means is configured to calculate in the form of the time required for rotation, and the ignition position is detected when the reference position is detected by steps 12 and 13 of the interrupt routine of FIG. 10 and the ignition timer interrupt routine of FIG. An ignition position detecting means for giving an ignition signal to the discharge thylister Thi when the measurement of the ignition position is completed is configured, and the rotation of the internal combustion engine is performed by steps 4 to 7 of the main routine of FIG. A cancel command generating means for generating a cancel command when the speed exceeds the set value is configured.

[0099] In a capacitor discharge type igniter, it is necessary to shut off the discharge thyristor before the positive half-wave voltage of the exciter coil rises. Therefore, as in the above example, the hard ignition signal Vih at the falling edge of the first and second pulse signals Vq1 and Vq2 obtained by waveform-shaping the negative half-wave voltages Vn1 and Vn2 of the exciter coil 6, respectively. It is necessary to extinguish the first and second pulse signals Vq1 and Vq2 before the positive half-wave output voltage of the exciter coil rises.

[0100] In the example shown in FIG. 1, the rising and falling edges of the first pulse signal are set at the rising and falling edges of the first negative half-wave voltage output by the exciter coil 6 , respectively. The waveform shaping circuit 11 is generated so that the rising and falling edges of the second pulse signal are generated at the rising and falling edges of the rising side of the second negative half-wave voltage output by the exciter coil, respectively. Although configured, as shown in Figures 6 (A) and 6 (B), the first negative half-wave voltage Vn1 output by the exciter coil is the first while it exceeds a certain threshold level Vth. The waveform shaping circuit 11 is configured to generate a pulse signal and generate a second pulse signal while the voltage of the second negative half-wave output by the exciter coil exceeds a certain threshold level. You can also.

[0101] As shown in FIG. 6, the first and second pulse signals Vq1 and Vq2 are output while the output voltages Vn1 and Vn2 of the first and second negative half waves of the exciter coil exceed the threshold level. To generate the voltage, for example, as shown in FIG. 2, the other end of the exciter coil 6 may be connected to the base of the NPN transistor TR1 through the resistor R2 ́ and the Zener diode ZD2. In this case, the threshold value Vth can be appropriately adjusted by the resistance value of the resistor R2 ́ and the Zener voltage of the Zener diode ZD2.

[0102] Further, the second power supply circuit 10B for applying the power supply voltage to the extremely low speed point-in-time fire control unit 12 is not limited to the one shown in FIG. 1, and is not limited to the one shown in FIG. A diode D10 ́ with an anode connected to the end, an NPN transistor TR5 with a collector connected to the cathode of the diode via a resistor R1 ́, a resistor R11 connected between the collector bases of the transistor TR5, and a transistor. It can also consist of a Zener diode ZD1 ́ connected between the base of TR5 and ground with the anode facing the ground side, and a power supply capacitor C1 ́ connected between the emitter of the transistor TR5 and ground.

In the second power supply circuit 10B shown in FIG. 2, when the negative half-wave output voltage of the exciter coil is equal to or less than the set value, the transistor TR5 conducts and the charging current is applied to the second power supply capacitor C1 ́. Shed. When the negative half-wave output voltage of the exciter coil exceeds the set value, the Zener diode ZD1 ́ conducts and the current given from the exciter coil through the resistors R1 ́ and R11 to the base of the transistor TR5 ́ is sided from the transistor. In order to pass the circuit, the transistor TR5 ́ is cut off and the charging of the capacitor C1 ́ is stopped. Therefore, the terminal voltage of the capacitor C1 ́ (the output voltage of the second power supply circuit 10B) is limited to the set value or less, and an excessive DC voltage is prevented from being output from the second power supply circuit 10B.

In this example, the diode D10 ́, the resistors R1 ́ and R11, and the transistor TR5 use the second power supply capacitor C1 ́ when the negative half-wave output voltage of the exciter coil is less than or equal to the set value. A charge control circuit is configured to charge and stop charging the second power supply capacitor C1 ́ when the negative half-wave output voltage of the exciter coil exceeds the set value.

[0105] The power supply voltage required to generate the hard ignition signal from the extremely low speed point-in-time fire control unit 12 may be lower than the voltage (5 [V]) required to operate the microcomputer 13A. As shown in 3, if a separate power supply is provided for the extremely low-speed point-in-time fire control unit 12, the rotation speed (starting rotation speed) at which the hard ignition signal is started to be supplied to the discharge thyristor is lowered, and the engine It is possible to improve the startability of the.

[0106] In the examples shown in FIGS. 1 and 2, a circuit (a circuit including a diode D10, a resistor R1, a capacitor C1 and a Zener diode ZD1) in a portion before the regulator Reg of the first power supply circuit 10A is used. It can also be replaced with a circuit having the same configuration as the second power supply circuit 10B shown in FIG.

[0107] In the above example, a signal generation unit is configured by the exciter coil 6 and a waveform shaping circuit that shapes the negative half-wave output voltage of the exciter coil into a pulse signal, and forms a negative half-wave output voltage of the exciter coil. The rising or falling edge of the pulse signal obtained by waveform-shaping the half-wave output voltage of the above was used as the reference position detection signal or the extremely low-speed point-of-time fire position detection signal. A signal generator can also be configured by a signal generator that generates a pulse signal at a position and an ignition position at an extremely low speed, and a waveform shaping circuit that shapes the output of the signal generator.

[0108] Fig. 3 shows an example in which a signal generator is configured by a signal generator and a waveform shaping circuit. In FIG. 3, 20 is a pulser coil provided in a signal generator attached to an internal combustion engine (not shown), and this pulser coil is provided in a signal generator attached to an internal combustion engine (not shown) in FIG. 12 (B). As shown in, the pulse waveform when the rotation angle position θ of the crankshaft of the internal combustion engine matches the reference position θ1 set at a position sufficiently advanced from the rotation angle position TDC corresponding to the top dead center of the engine. The first signal P1 of the internal combustion engine is generated, and the second signal P2 of the pulse waveform is generated when the rotation angle position of the internal combustion engine matches the position θ2 suitable as the ignition position at the time of starting and at extremely low speed.

[0109] The signal generator includes, for example, a rotor having a retractor and attached to a crankshaft or the like so as to motivate rotation with the engine, and an iron core having a magnetic pole portion facing the retractor of the rotor at the tip. , A pulsar coil wound around the iron core and a permanent magnet that allows magnetic flux to flow through the iron core, and pulse waveforms with different polarities when the front end side edge and the rear end side edge in the rotation direction of the retractor are detected, respectively. It is composed of signal generators that generate signals P1 and P2.

Reference numeral 11 denotes a waveform shaping circuit, in which the first signal P1 and the second signal P2 output by the pulsar coil 20 are waveform-shaped to obtain the reference position detection signal Vs1 and the extremely low speed time point fire position detection signals Vs2 and Vs2'. Output. Of these signals, the extremely low-speed point-of-fire position detection signal Vs2 is a passive element (capacitor) when the input signal P2 exceeds the threshold value, similar to the pulse signal Vq2 in the examples shown in FIGS. 1 and 2. It is a signal output through a parallel circuit with a resistor and a Zener diode), and is a signal generated immediately after the start operation of the engine is started. The other signals Vs1 and Vs2'are signals output through an amplification element such as a transistor. Of the parts of the waveform shaping circuit 11, the parts that generate the signals Vs1 and Vs2'operate using the output voltage of the first power supply circuit 10A as the power supply voltage.

The reference position detection signal Vs1 and the extremely low speed point fire position detection signal Vs2'are input to ports A11 and A12 of the microcomputer 13A.

[0112] In the extremely low speed point-in-time fire control unit 12, the emitter is connected to the output terminal 20b of the second power supply circuit 10B through the resistor R20, and the collector is connected to the gate of the discharge thyristor Tih through the diode D6. It consists of TR6 and an NPN transistor TR7 in which the emitter is grounded and the collector is connected to the base of transistor TR6. The extremely low speed point-of-fire position detection signal Vs2 is input to the base of transistor TR7. Other points are the same as those of the ignition device shown in FIG.

In the example shown in FIG. 3, the transistor TR7 conducts when the pulsar coil 20 generates the second signal P2 and the waveform shaping circuit 11 generates the extremely low-speed point-of-time fire position detection signal Vs2. As a result, the transistor TR6 conducts and gives an ignition signal to the discharge thyristor Thi.

[0114] The microcomputer 13A detects the rotation speed of the engine from the generation interval between the signal Vs1 and the signal Vs2', and calculates the ignition position at the detected rotation speed. The microprocessor also starts the measurement of the ignition position calculated when the reference position detection signal Vs1 is generated, and outputs the ignition signal Vk when the measurement is completed to perform the ignition operation.

[Effect of the Invention] As described above, according to the present invention, the power supply circuit provided to the extremely low speed time point fire control unit that gives an ignition signal to the discharge thyristor at the time of starting the internal combustion engine and at an extremely low speed is provided at a steady time. Since it is provided separately from the power supply circuit that applies the power supply voltage to the fire control unit, the extremely low speed time point fire control unit can be operated before the steady time point fire control unit starts operation.

[0116] Therefore, not only can the starting rotation speed of the engine be lowered to improve the startability of the engine, but also the idling region of the engine can be stably rotated.

BRIEF DESCRIPTION OF THE DRAWINGS [Fig. 1] Fig. 1 is a circuit diagram showing a configuration example of hardware according to an embodiment of the present invention.

FIG. 2 is a circuit diagram showing another configuration example of the hardware according to the embodiment of the present invention.

FIG. 3 is a circuit diagram showing still another configuration example of the hardware according to the embodiment of the present invention.

FIG. 4A is a configuration diagram showing a configuration of a magneto generator used in the ignition device according to the present invention, and FIG. 4B is a waveform diagram showing a waveform of an output voltage obtained from the generator.

5 is a waveform diagram for explaining the operation of the waveform shaping circuit used in the embodiment of FIG. 1. FIG.

FIG. 6 is a waveform diagram for explaining the operation of the waveform shaping circuit used in the embodiment of FIG.

FIG. 7 is a waveform diagram showing voltage waveforms of each part of the embodiments shown in FIGS. 1 and 2 with respect to the rotation angle of the crankshaft of the engine.

FIG. 8 is a waveform diagram for explaining the operation of the embodiment of the present invention.

FIG. 9 is a flowchart showing an example of an algorithm of a main routine of a program to be executed by a microcomputer of a stationary point-in-time fire control unit in the embodiment of the present invention.

FIG. 10 is a flowchart showing an example of an algorithm of a pulse edge interrupt routine of a program to be executed by a microcomputer of a stationary point-in-time fire control unit in the embodiment of the present invention.

FIG. 11 is a flowchart showing an example of an algorithm of an ignition timer interrupt routine of a program to be executed by a microcomputer of a stationary point-in-time fire control unit in the embodiment of the present invention.

FIG. 12 (A) shows a waveform diagram showing the waveform of the voltage output by the exciter coil of the ignition device of FIG. 3, and FIG. 12 (B) shows an example of the waveform of the signal output by the pulser coil of the ignition device of FIG. It is a waveform diagram.

[Explanation of symbols] 6 ... Exciter coil, 10 ... Power supply circuit for control, 11 ... Waveform shaping circuit, 12 ... Extremely low speed point fire control unit, 13 ... Steady operation time point fire control unit , 14 ... Or circuit, IG ... Ignition coil, Ci ... Ignition capacitor, Thi ... Discharge thylister.