JPH03271565A - Ignition device for internal combustion engine - Google Patents

Abstract

PURPOSE:To prevent an unexpected start-time control mode from being performed by performing control operation from the start-time control mode, when an engine is started, and skipping the start-time control mode to perform control operation from a steady-time control mode in the case of a microcomputer being reset. CONSTITUTION:An integration capacitor 12 is charged by a predetermined time constant through a charging circuit 11 by a power supply circuit 3. The integration capacitor 12 is discharged by a predetermined time constant by a discharging circuit 13. In a mode control means 14, an ignition timing control device 5, after it is started from a start-time control mode, is transferred to a steady-time control mode when terminal voltage is less than a preset value by detecting the terminal voltage of the integration capacitor 12. An operation start-time control mode of the ignition timing control device 5 is controlled so as to be started from the steady-time control mode without performing the start-time control mode when the terminal voltage is at the preset value or higher.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an ignition device for an internal combustion engine in which the ignition timing of the internal combustion engine is controlled by a microcomputer.

[Prior Art] In internal combustion engines for ships, an alternator driven by the internal combustion engine is used as a power source to operate the ignition circuit so that ignition can be performed without using a battery. ing.

Recently, ignition timing has been controlled using a microcomputer, but if a battery is not installed, it is stabilized by rectifying the output of a generator driven by an internal combustion engine. A power supply circuit for obtaining DC voltage is provided, and power is supplied to the microcomputer from the power supply circuit.

When controlling ignition timing using a microcomputer, various means for determining ignition timing are realized by programs stored in a ROM within the microcomputer.

In many cases, internal combustion engines are warmed up by increasing their rotational speed when starting the engine.

In an ignition system using a microcomputer, after the engine starts, a starting control mode is performed in which the ignition timing is advanced by a predetermined amount for a certain period of time to perform warm-up operation.
After the start-up control mode ends, the steady-state control mode is entered.

For example, in an outboard motor, the ignition timing of the engine is advanced for a certain period of time (for example, 10 to 30 seconds) immediately after the engine starts, and the engine speed is lowered to idling speed (usually 600 rpm).
The engine is warmed up to about 1200 rpm, which is higher than the engine speed (approx. .

By the way, if the ignition timing is controlled by a microcomputer, if the microcomputer breaks down, the ignition timing will no longer be controlled.However, in internal combustion engines for vehicles and ships, the microcomputer is used to ensure driver safety. It is desirable to be able to continue operating the engine even if the computer fails. Particularly in the case of a ship, if the engine stops, it is dangerous to return to port, so it is necessary to ensure that the ignition system continues to operate even if the microcomputer fails.

Therefore, in an ignition system that uses a microcomputer to control ignition timing, a preliminary ignition signal supply circuit that supplies a preliminary ignition signal to the ignition circuit from a system separate from the microcomputer is usually provided.

In addition, in order to operate the microcomputer reliably, it is necessary to maintain the power supply voltage within a predetermined range. , the microcomputer may malfunction or become inoperable. Therefore,
In an internal combustion engine ignition system using a microcomputer, a means is provided to reset the microcomputer when the power supply voltage drops below a specified level, and when the power supply voltage drops, the control operation by the microcomputer is temporarily stopped. An ignition signal is supplied to the ignition circuit from a separate signal supply circuit, so that when the power supply voltage is restored and the microcomputer resumes operation, the program is started from the beginning.

[Problems to be Solved by the Invention] As described above, in an ignition system for an internal combustion engine that uses a microcomputer to control ignition timing, the output voltage of the generator decreases due to some reason, causing the output of the power supply circuit to decrease. When the voltage decreases, the reset means operates to reset the microcomputer.

In conventional ignition systems, when the microcomputer is reset in this way, the program is executed from the beginning when the power supply voltage is restored, resulting in an unexpected starting control mode and a sudden increase in engine speed. , which could pose a danger to the driver.

For example, when an outboard motor is trolled at a low speed of around 600 rpm and the transmission is switched to the reverse position, a large load is applied to the internal combustion engine when the screw reverses, causing the engine's rotational speed to drop. Therefore, the output of the generator decreases, the output voltage of the power supply circuit drops, and the microcomputer may be reset. In this case, when the rotational speed of the engine is restored, the microcomputer executes the program from the beginning, so the starting control mode is first performed and the ignition timing is suddenly advanced. Therefore, the rotational speed of the engine suddenly increases to about 120 rpm, and the ship suddenly retreats at a high speed. If such a situation occurs, there is a risk of an accident such as the operator falling into the water, which is dangerous.

An object of the present invention is to perform a control operation from the starting control mode when starting the engine, and when the microcomputer is reset due to an instantaneous drop in power supply voltage, the starting control mode is skipped and the control operation is switched to the steady state control mode. An object of the present invention is to provide an ignition device for an internal combustion engine that prevents an unexpected startup control mode from being performed by performing a control operation from the start.

[Means for Solving the Problems] As shown in FIG. 1, the ignition device to which the present invention is directed includes an alternating current generator 2 driven by an internal combustion engine 1, and an alternating current generator 2 that rectifies the output of the generator. a power supply circuit 3 that outputs a DC voltage;
An ignition circuit 4 is powered by a generator and generates a high voltage for engine ignition when an ignition signal is given, and a microcomputer driven by the output of the power supply circuit 3 controls the timing of giving the ignition signal to the ignition circuit 4. an ignition timing control device 5, a reset means for resetting the ignition timing control device 5 to an initial state when it is detected that the output voltage of the power supply circuit 3 has become lower than a specified level for operating the microcomputer, and a power supply circuit. The ignition timing controller 5 includes an ignition timing control device 5 and a preliminary ignition signal supply circuit 7 which supplies a preliminary ignition signal to the ignition circuit from another system when the output voltage of the ignition circuit 3 is lower than a specified level.

The ignition timing control device 5 includes a starting control means 8 and a steady state control means 9.

The starting control means 8 advances the ignition timing for a certain period of time immediately after starting the internal combustion engine, increases the rotational speed during the period, and performs warm-up operation.

Further, the steady state control means 9 performs a control operation to control the ignition timing in accordance with predetermined control conditions such as the opening degree of the throttle valve and the rotational speed of the engine.

In the example shown in FIG. 1, it is assumed that the opening degree of the throttle valve is detected by the throttle sensor 10 and the ignition timing is controlled in accordance with the opening degree of the throttle valve.

In the present invention, the integrating capacitor 12 charged by the power supply circuit through the charging circuit 11 at a predetermined time constant, the discharging circuit 13 discharging the integrating capacitor at a predetermined time constant, and the ignition timing control device start operating. When the terminal voltage of the integrating capacitor 12 is detected and the terminal voltage is less than the set value, the control operation of the ignition timing control device 5 is started from the starting control mode, and after the starting control mode is finished, the control operation is started. Shift to constant control mode, integrate capacitor 1
mode control means 14 for controlling the mode at the start of operation of the ignition timing control device so as to start from the steady state control mode without performing the start time control mode when it is detected that the terminal voltage of No. 2 is higher than the set value; has been established.

[Function] With the above configuration, the following conditions can be created by appropriately setting the charging time constant and discharging time constant of the integrating capacitor.

(a) Immediately after the engine starts, the terminal voltage of the integrating capacitor does not reach the set value.

(b) If the output voltage of the generator momentarily drops for some reason while the engine is in steady operation, and the voltage of the generator recovers after the microcomputer is reset, the terminal of the integrating capacitor The voltage is maintained at a value higher than the set value.

If the charging time constant and discharging time constant of the integrating capacitor are set as described above, the mode control means 14 first performs the starting control mode and then performs the steady state control mode when starting the engine. In addition, when the generator output voltage decreases due to some reason such as an increase in engine load during steady operation and the microcomputer is reset, if the generator output voltage recovers, no control operation is performed at startup. Start the steady state control operation. Therefore, it is possible to prevent the rotational speed of the engine from suddenly increasing due to unexpected start-up control immediately after the voltage of the generator is restored, and safety can be improved.

[Embodiments] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 2 schematically shows the configuration of an ignition timing control device that implements the method of the present invention. In this embodiment, it is assumed that a three-cylinder two-stroke internal combustion engine is to be ignited.

The ignition circuit 4 has three cylinders corresponding to three cylinders of the engine.
ignition coils 401 to 403, and thyristors 404 to 4 whose cathodes are connected to the non-ground terminals of the primary coils of these ignition coils and whose anodes are commonly connected.
06, an energy storage capacitor 407 connected between the common connection point of the anodes of the thyristors 404 to 406 and ground, and a diode 408 whose cathode is connected to the gates of the thyristors 404 to 406, respectively.
410 to 410, diodes 411 and 412 whose cathodes are connected to the gates of thyristors 404 and 406, respectively, and whose cathodes are connected to the non-grounded terminal of a capacitor 407, and are provided in the magnet generator 2 attached to the engine. A diode 413 whose anode is connected to one end of the exciter coil 2A, and diodes 414 and 415 which are connected between the anode of the diode 413 and the ground and between the other end of the exciter coil 2A and the ground, respectively, with their anodes facing the ground side. We are prepared.

On the secondary side of the ignition coils 401 to 403, the first
Spark plugs Pa to Pc attached to the first to third cylinders, respectively, are connected.

In reality, components such as a resistor for protecting the thyristor are further provided, but illustration of these components is omitted.

In this example, the anodes of the diodes 408 to 410 are the first one provided from the microcomputer side.
The anodes of diodes 411 and 412 serve as input terminals for an ignition signal supplied from a preliminary ignition signal supply circuit provided separately from the microcomputer.

This ignition circuit is a known capacitor discharge type ignition circuit, and its operation will be explained as follows.

The exciter coil 2A induces an alternating voltage in synchronization with the rotation of the engine, and the capacitor 407 is charged with the voltage of one half cycle of the alternating voltage to the polarity shown. Thyristor 4
Ignition signals are applied to the gates 04 to 406 at the ignition timings of the first to third cylinders, respectively. When an ignition signal is applied to one of the thyristors, the thyristor to which the ignition signal is applied becomes conductive, and the charge in the capacitor 407 is discharged through the thyristor to the primary coil of the ignition coil, which ignites the secondary coil of the ignition coil. High voltage is generated. Since this high voltage is applied to the ignition plug, a spark is generated in the ignition plug and the engine is ignited.

The magnet generator 2 includes a flywheel 21 attached to the output shaft of the engine, and has a permanent magnet (not shown) on its inner periphery.

) is attached. An armature (not shown) around which the exciter coil 2A is wound is arranged inside the flywheel 21, and as the flywheel 21 rotates, an alternating current voltage is induced in the exciter coil 2A. The generator 2 is constituted by a flywheel 21, a permanent magnet attached to the inner periphery of the flywheel, and an armature around which an exciter coil 2A is wound.

An iron ring gear 22 is fixed to the outer periphery of the flywheel 21 for engaging a pinion gear of an engine starting device, and an inductor-type signal generator 23 is arranged opposite to the ring gear 22. The output of 23 is input to a waveform shaping circuit 24.

The signal generator 23 includes an iron core including a magnetic pole portion facing the teeth of the ring gear 22, and a signal coil wound around the iron core.
A well-known type equipped with a permanent magnet that causes magnetic flux to flow through the iron core,
Each time each tooth of the ring gear 22 faces a magnetic pole portion of the iron core of the signal generator 23, a pulse-like signal is induced in the signal coil.

The signal generated from the signal generator 23 is sent to the waveform shaping circuit 24.
As shown in FIG. 11(B), the polarity is equal and 1
The number of pulses generated per revolution is converted into a pulse signal equal to the number of teeth of the ring gear. This pulse signal is input to input ports a2 and a3 of the microcomputer 30.

An arc-shaped inductor magnetic pole part 25 having a polar arc angle of 120 degrees in mechanical angle is formed on the outer periphery of the boss part 21A of the flywheel, and the rotor 26 of the signal generator is constituted by the boss part. A signal generator 27 is opposed to this rotor, and the rotor and signal generator 27 constitute a signal generator 28 . The signal generator 27 is of a well-known type, and includes an iron core having a magnetic pole portion at its tip opposite to the inductor magnetic pole portion 25, a signal coil wound around the iron core, and a permanent magnet that causes a speed to flow through the iron core. With the rotation of the boss part 21A
When the leading and trailing ends of the inductor magnetic pole part 25 pass the position of the magnetic pole part of the signal generator 27 during the rotation process, signals Vp and Vq as shown in FIG. 11(A) are outputted. In this example, the signal Vp exceeds the threshold level at the minimum advance angle position of the third cylinder of the engine (for example, 5 degrees before the top dead center of the third cylinder), and the signal Vq reaches the minimum advance angle position of the third cylinder of the engine. Adjustment is made so that the advance angle is equal to or higher than the threshold level at the minimum advanced angle position (for example, 5 degrees before the top dead center of the first cylinder).

Signals Vp and Vq obtained from the signal generator 27 are input to waveform shaping circuits 29A and 29B, respectively, and converted into pulse-like signals. The waveform shaping circuit 29A outputs the signals Vp' and Vi3 when the signal Vp becomes equal to or higher than the threshold level, and the white signal Vp' of these signals is sent as a reference signal to the input port a1 of the microcomputer 30 through the OR circuit 31. is entered as . Also, the signal Vi
3 connects the thyristor 4 of the ignition circuit through the diode 412
It is input to the gate of No. 06 as a preliminary ignition signal for the third cylinder. The waveform shaping circuit 29B changes the signal Vq' and Vil when the signal Vq becomes equal to or higher than the threshold level.
Output. Signal Vq + is microcomputer 3
0 input port a4, and the signal Vil is input through the diode 411 to the gate of the thyristor 404 of the ignition circuit as a preliminary ignition signal for the first cylinder.

In addition, the signals Vi3 and V of the waveform shaping circuits 29A and 29B
A switch circuit 32 is provided between the output terminals that respectively output il and ground. When the microcomputer 30 is operating, a signal is applied to the trigger signal input terminal of the switch circuit 32 from the output port Ao3 of the microcomputer. In this state, the switch circuit 32 is conductive and short-circuits the signals Vi3 and Vil.
The ignition signal is prevented from being applied to the ignition circuit through diodes 411 and 412. When the microcomputer stops operating, the switch circuit 32 is cut off, and the signals Vi3 and Vil output from the waveform shaping circuits 29A and 29B are applied to the ignition circuit 4.

In this embodiment, the signal V of the waveform shaping circuits 29A and 29B is
The portion that generates i3 and Vil and the switch circuit 32 constitute a preliminary ignition signal supply circuit.

If the preliminary ignition signals Vi3 and Vil are given to the ignition circuit in this way, even if the microcomputer (described later) fails, the signal generator 28 will be activated at the minimum advance position.
An ignition signal can be applied from the side to the ignition signal input terminals for the third and first cylinders of the ignition circuit 4, whereby two of the three cylinders can be ignited to maintain the rotation of the engine.

With this configuration, even if the microcomputer fails, two of the three cylinders can be ignited, allowing the engine to continue operating. Particularly in the case of outboard motors, such consideration is necessary because if the engine stops, it will be impossible to return to port, which is dangerous.

The microcomputer 30 includes a CPU 30a, a ROM 30b storing a predetermined program, a RAM 30c into which data is written at any time, a register 30d into which the ignition timing measurement time is input, a timer counter 30e which counts clock pulses, and a timer counter 30e which counts clock pulses. A comparator 30f that outputs a signal when the contents of the register 30d and the count value of the timer counter 30e match, and an input port a from the OR circuit 31.
a latch means 30g that latches the count value of the timer counter 30e every time a signal is applied to the input capo a2; and a first counter 30h that counts the pulse signal applied to the input capo a2.
and a second register 30i into which the first and third counted values Nlx and N2 are sequentially input, and when the counted value of the counter 30h matches the contents of the second register 30i, a signal is sent from the output port Aol to the OR circuit 31. a comparator 30j that gives a value of The comparator 30p outputs a signal from the output port Ao2 to the OR circuit 31 when the counted value matches the content of the third register 30n, and these are interconnected by an internal bus.

The power supply circuit 3 includes a diode 41 of the exciter coil 2A.
It consists of a diode 301 whose anode is connected to the terminal on the 5 side, a power supply capacitor 302 connected between the cathode of the diode 301 and ground, and a constant voltage circuit 303 that stabilizes the voltage across the capacitor 302. The constant voltage circuit 303 is constituted by a circuit that charges the capacitor 302 or bypasses current from the capacitor 302 when the terminal voltage of the capacitor 302 exceeds a certain level, for example.

The output voltage of this power supply circuit 3 is
is applied to the power supply terminal E1.

In addition, a diode lla is connected to the non-grounded output terminal of the power supply circuit 3.
One end of an integrating capacitor 12 is connected through the resistor 11b and the other end of the integrating capacitor 12 is grounded. Power supply circuit 3→diode 11a→resistance 11b→integrating capacitor 12→integrating capacitor 12 by the circuit of power supply circuit 3
A charging circuit is configured. Also, the integral capacitor 12
The non-ground terminal of is connected to the output terminal of the power supply circuit 301 through the resistor 13b and the diode 13a, and the integration capacitor 12 → resistor 13b → diode 13a → power supply circuit 3
The circuit connected to the ground inside and the microcomputer 30
A discharging circuit is configured to discharge the integrating capacitor 12 at a constant time constant through a circuit connected to the ground inside.

The voltage across the integrating capacitor 12 is input to the input port a6 of the microcomputer 30 as a signal for checking whether there is an abnormality in the power supply.

A throttle sensor 10 that detects the opening degree of a throttle valve of an engine is composed of a potentiometer IOA to which the output of a power supply circuit 30 is applied, and the output of this sensor is input to an input port a5 of the microcomputer 30.

The microcomputer 30 is configured with the function realizing means 8, 9, and 14 shown in FIG. 1 by a predetermined program according to an algorithm to be described later, and measures the ignition timing of the first to third cylinders of the engine. When this happens, ignition signals for the first to third cylinders are output from the input/output (I10') interface 30k to the output ports A'1 to A3, respectively. The ignition signals obtained at these output ports A1 to A3 are input to the anodes (ignition signal input terminals) of diodes 408 to 410 of the ignition circuit 4, respectively.

The program stored in the ROM of the microcomputer is created according to the control algorithms shown in, for example, FIGS. 3 to 5 and 7. The main routine is as shown in FIG. 3. When the program is started, initial settings of each part are first performed, and then interrupts are enabled. When the signal Vp is generated and the reference signal Vp+ is input to the input port "al" as shown in FIG. 11(A), the interrupt routine of FIG. 4 is executed and the first number is stored in the second register 30i. Nlx is set, and the count value of the timer counter 30e (the time when the reference signal is input to the input port a1) is latched, and that value is sent to the RA.
Stored in M. Then return to the main routine. At the same time as the first number Nlx is set in the second register 30i, the first counter 30h starts counting the pulse signals shown in FIG. 13(B).

Since the target ignition timing is not calculated in the main routine until the start of the engine is confirmed, no ignition signal is given from the microcomputer to the ignition device.

In this state, the microcomputer's output port Ao3
Since no trigger signal is supplied from the switch circuit 32 to the switch circuit 32, the switch circuit 32 is in a cut-off state. Therefore, when the signal generator 27 generates the signals Vp and Vq, the ignition signal input terminal for the third cylinder (the anode of the diode 412) and the ignition signal input terminal for the first cylinder (the anode of the diode 411) are connected to each other. Ignition signals Vi3 and Vil are applied to ignite the two cylinders of the engine.

This causes the engine to rotate and its speed increases. When the rotational speed of the engine increases to a certain degree, starting of the engine is confirmed. To confirm this start, the signal generator 27 outputs the signal Vp.
This is done by determining the length of time from the time when the reference signal (reference signal) is generated to the time when the signal Vq (given to the input port a4) is generated.

When starting of the engine is confirmed, a trigger signal is given to the switch circuit 32 from the output port A03 of the microcomputer, so the switch circuit becomes conductive and the preliminary ignition signal V
i3 and Vil are prevented from being applied to the ignition circuit 4.

Further, when it is confirmed that the engine has started, it is checked in the main routine shown in FIG. 3 whether or not there is an abnormality in the power supply.

The presence or absence of a power supply abnormality is confirmed by comparing the terminal voltage Vc of the integrating capacitor 12 with the set value Vs. In this embodiment, the charging time constant and discharging time constant of the integrating capacitor 12 are set so as to satisfy the following conditions.

(a) Even if the engine is started two or three times, the terminal voltage Vc of the integrating capacitor should not reach the set value Vs immediately after starting.

(b) If the output voltage of the generator momentarily drops for some reason while the engine is in steady operation, and the voltage of the generator recovers after the microcomputer is reset, the terminal of the integrating capacitor The voltage Vc is maintained at a value equal to or higher than the set value V+.

In this embodiment, the charging time constant and discharging time constant of the integrating capacitor 12 can be adjusted separately by adjusting the resistance values of the resistors 11b and 13b. Note that these time constants do not necessarily have to be different, and may be equal as long as the above conditions are satisfied.

The terminal voltage of the integrating capacitor 12 is compared with the set value. If the terminal voltage of the integrated integral capacitor 12 is less than the set value, it is determined that there is no abnormality in the power supply. If the terminal voltage of the integrating capacitor 12 is equal to or higher than the set value, it is determined that there is an abnormality in the power supply. It is determined that this has occurred.

Immediately after it is confirmed that the engine has started, as shown in (a) above, the terminal voltage of the integrating capacitor 12 has not reached the set value, so it is determined that there is no abnormality in the power supply. At this time, the starting control mode is performed, and the ignition timing advanced by a predetermined amount is set as the target ignition timing.

When the startup control is completed, the mode shifts to steady control mode, and the throttle valve opening (each time the throttle opening is changed, the detection means detects it and records the RA as digital information).
It is stored in M. ), the target ignition timing is calculated.

In addition, for safety, the engine is checked for abnormalities such as overheating or overspeeding, and if an abnormality is found, the ignition timing is retarded or the ignition spark is thinned out to keep the engine speed below a safe speed. or cause a specific cylinder to misfire, but since this is outside the scope of the present invention, a detailed explanation will be omitted. Note that this process for ensuring safety can also be omitted.

As shown in FIG. 11(C), at time TII, the count value of the pulse signal of the first counter 30h is changed to the second register 30i.
If it matches the first number Nlr inputted in the output capo-h
A signal is given from Aol to the input port a1 through the OR circuit 31, and the count value of the timer counter 30e at that time (
Time T when counting of the first number N11 pulse signals is completed
11) is latched.

Also, the count value of the first counter 30h is the second register 30h.
The interrupt routine shown in FIG. 5 is executed every time the contents of i match. In this interrupt routine, it is first determined whether the counting of pulse signals of the third number N3 has been completed, and then it is determined whether the counting of the pulse signals of the second number N2 has been completed. However, at the stage where the counting of the pulse signals of the first number NIX is completed, the second number N2 and the third number N3
Since the counting has not yet been completed, the process proceeds to the step of storing the counted value of the timer counter 30e. As a result, the time TII when counting of the first number NIX is completed is stored. Next, a second number N2 is set in the second register 30i, a third number N3 is set in the third register 30n, and the process returns to the main routine.

When the second number is set in the second register 30i, the 11th
As shown in Figure (C), the first counter 30h immediately starts counting the second number N2. Also, the third register 30n
When the third number N3 is set, the second counter 30m starts counting pulse signals as shown in FIG. 11(D).

When the counted value of the first counter 30h matches the second number N2 inputted to the second register 30i, the counted value of the timer counter 30e is latched, and the interrupt routine of FIG. 5 is executed again, and the latched The counted value of the timer counter 30e (time T2K at which counting of the second number N2 is completed) is stored. Then the second register 30i
After setting the first number Nlx for the next cylinder, a process of calculating the ignition timing measurement time is performed. In this process, the time T2X at which the counting of the second number N2 of pulse signals is completed and the first
Information on the rotational speed of the engine is obtained from the difference from the time T1x when the counting of the number Nlx of pulse signals ends and the rotation angle during that time (obtained from the number of teeth N2 of the ring gear).
The data of the ignition timing Ti calculated in the main routine is calculated from the time when counting of the third number N3 is completed to the ignition timing T.
Convert to ignition timing measurement time Jti, which is equal to the time up to i. After that, return to the main routine.

Next, when the count value of the counter 30m matches the third number N3 set in the third register 30n, the count value of the timer counter 30e is latched and the interrupt routine of FIG. 5 is executed again. At this time, in the interrupt routine shown in FIG. 5, first a cylinder discrimination flag indicating the cylinder to be ignited is set, then the already calculated ignition timing measurement time is set in the first register 30d, and the process returns to the main routine.

When the count value of the timer counter 30e matches the contents of the first register 30d, the interrupt routine shown in FIG.
An ignition signal is applied to the ignition signal input terminal of the cylinder (cylinder).

When the first counter 30h finishes counting the first number Nlx set in the second register 30i, the interrupt routine of FIG. 5 is executed again.

Thereafter, the same operation as above is repeated twice, and the second cylinder and the third cylinder are ignited. When the signal Vp is generated again after the third cylinder is ignited, the reference signal Vp+ is applied to the microcomputer through the OR circuit 31, so that the program is executed from the interrupt routine shown in FIG.

As shown in FIG. 10 (A), when the rotational speed of the engine decreases for some reason during steady operation of the engine, and the output voltage Vo of the power supply circuit 3 at time Tu falls below the specified value Vs, The microcomputer is reset. At this time, the trigger signal given to the switch circuit 32 from the output port Ao3 of the microcomputer disappears, so the switch circuit 32 is cut off, and the preliminary ignition signal Vi3
and Vil are now applied to the ignition circuit 4. Therefore, when the microcomputer is in the reset state, the ignition circuit continues to operate due to the pre-ignition signal.

When the output voltage of the power supply circuit 3 is restored at time Tv, the main routine shown in FIG. 3 is started from the beginning.

Since the discharging time constant of the integrating capacitor 12 is set so that the terminal voltage of the integrating capacitor 12 does not fall below the set value due to an instantaneous voltage drop that occurs during engine operation, an abnormality in the power supply is confirmed at time Tw. When this step is performed, the terminal voltage of the integrating capacitor 12 is still at the set value V.
It is in a higher state than s. In this case, in the step of determining whether there is an abnormality in the power source, it is determined that an abnormality has occurred in the power source (output of the generator), and a command is issued to shift to the steady-state control mode without performing the start-up control mode. In steady state control mode, the target ignition timing is adapted to the opening of the throttle valve at that time, so the ignition timing will not advance unexpectedly and the engine speed will not suddenly increase. .

In this way, in the present invention, after the power supply voltage drops during engine operation and the microcomputer is reset, when the microcomputer starts operating, the startup control mode is skipped and the mode shifts to the steady state control mode. As a result, it is possible to prevent the engine rotational speed from rapidly increasing due to unexpected start-up control.

In the above embodiment, the steps from the step of determining whether the starting control shown in FIG. 3 has ended to setting the ignition timing for starting control as the target ignition timing,
The start-up control means is realized by each step of the interrupt routine shown in FIG. 7 and FIG.

In addition, the step and the fourth step after the steady state control mode in Fig.
A steady state control means is realized by each step of the interrupt routine shown in FIG. 5, FIG. 5, and FIG. 7.

Further, in the main routine of FIG. 3, a mode control means is realized by the step of checking whether there is an abnormality in the power supply and shifting to the start-up control mode or the steady-state control mode.

When calculating the ignition timing by calculating the time from the predetermined measurement start position to the target ignition timing as the ignition timing measurement time as described above and measuring the ignition timing measurement time from the measurement start position, the ignition timing measurement If the rotational speed information used to calculate the time is not accurate, the ignition timing cannot be accurately matched with the target ignition timing.

In an actual internal combustion engine, the rotational speed varies minutely, so in order to accurately determine each ignition timing, it is preferable to determine the ignition timing based on the rotational speed at a time as close as possible to each ignition timing.

FIG. 13 shows variations in the rotational speed of a two-stroke, three-cylinder internal combustion engine. As seen in the figure, in a two-stroke engine, the rotational speed decreases the most at the end of the compression stroke, and the rotational speed reaches its maximum at a position of 30 to 60 degrees after ignition due to explosion.

Furthermore, if the gas in the cylinder is not replaced well during the scavenging stroke, combustion will not be performed well during the subsequent explosion stroke, resulting in a low maximum rotational speed. When the gas is successfully replaced in the next scavenging stroke, combustion is performed well in the subsequent explosion stroke, and the rotational speed increases. Therefore, the rotational speed varies with each rotation.

In the conventionally widely used ignition timing control system, the 13th
As shown in the figure, the time from time Ta immediately after ignition to time Tb immediately after the next ignition is measured, and a timer for measuring ignition timing is started at time Tb. Then, while the ignition timing measurement timer is performing counting operation, from time Ta to Tb
Calculate the average value of the rotational speed from the time until then and the rotation angle during that time, calculate the target ignition timing measurement time necessary to determine the ignition timing at that time based on this rotational speed, and measure the ignition timing. Set the end time in the ignition timing measurement timer. When the ignition timing measurement timer times up, an ignition signal is given to the ignition circuit to cause the ignition operation to occur.

In this way, using the rotational speed generated by the previous ignition as the rotational speed data used to determine each ignition timing, the rotational speed data used to determine each ignition timing and the rotational speed data used to determine it are Since there is no correlation between the two, it is not possible to accurately determine the ignition timing.

In contrast, in the embodiments described above, the ignition timing measurement time is determined based on the rotational speed detected immediately before the ignition timing, so that the deviation between each ignition timing and the target ignition timing can be minimized.

In the above embodiment, the rotational speed information is obtained from the time from time Tlx when the counting of the first number NIX pulse signals ends to time Tb when the counting of the second number N2 pulse signals ends. It is desirable to set the period for obtaining this rotational speed information to a period in which the instantaneous rotational speed of the engine is relatively stable (with little change from rotation to rotation). Further, it is desirable that this period be close to the time when measurement of the ignition timing is actually started. In the present invention, by appropriately setting the first number Nb, the period (
(period for counting the second number N2 of pulse signals) can be set at any position.

In a two-cycle engine, it is preferable to set the period for counting the second number N2 of pulse signals in a region (compression stroke) in which the rotation of the engine relies on inertia and the rotational speed decreases. In order to bring the area for counting the second number N2 to the optimal area according to the engine characteristics and engine rotation speed, the first number Nlx is determined based on the engine characteristics and rotation speed (second number N2). (obtained from the time for counting pulse signals) can be changed as appropriate.

In addition, if the number of pulse signals generated per revolution is not divisible by the number of cylinders, the position where the reference signal is generated is set to a position where no pulse signal is generated, and the The first number Nlx for each cylinder is set so that the angular interval between the positions where the first counting operation ends is approximately equal to 360/n. In this case the first number Nl
x takes a different value depending on the cylinder. For example, when controlling the ignition timing of a three-cylinder internal combustion engine, the first number N for the first cylinder
If b=N 1, then the first number N1. for the second cylinder.
x becomes NIx=Nl±α, and the first number NII for the third cylinder becomes Nb=Nl±β. Here, α and β are integers (including O).

In the above embodiment, counting of the third number N3 is started from time Tlx when counting of the first number Nlx ends. In this case, the first. It is necessary that the sum of the time for counting the number Nlr and the time for counting the third number N3 is shorter than the ignition interval between the cylinders. Therefore, in order to accurately control the ignition timing from a low speed range to a high speed range of the engine, it is preferable to change the first number N1x and the third number N3 as appropriate depending on the rotational speed of the engine.

Note that the counting end time of the third number N3 needs to be set after the time when the calculation of the rotational speed and the calculation of the ignition timing measurement time end after the counting of the second number N2 is completed. Of course.

As described above, after counting the number Nlx of pulse signals, the time T3 is when the third number N3 of pulse signals is further counted.
By starting the ignition timing measurement from x, not only can the ignition timing measurement time be calculated during that time, but also after obtaining the rotation speed information at time T2I,
It is possible to correct errors caused by speed fluctuations that occur up to time T3x when measurement of the ignition timing measurement time actually starts. That is, if the rotational speed increases between time T21 and time T3I, the calculated ignition timing measurement time will be too long, but in this case, the position at which the ignition timing measurement time starts will be earlier. The deviation between the actual ignition timing and the target ignition timing can be reduced.

Time T2 again! If the rotation speed decreases between T3K and time T3K, the calculated ignition timing measurement time will be too short, but in this case, the position at which the ignition timing measurement time starts will be delayed, so the actual ignition timing will be delayed. The deviation between the timing and the target ignition timing can be reduced.

In the above embodiment, a ring gear is used to obtain a pulse signal, but in the present invention, it is sufficient to obtain a pulse signal generated at each minute rotation angle of the engine, and a member that rotates synchronously with the engine, for example, The encoder may be configured with a code plate attached to the flywheel and a sensor for reading the code provided on the code plate, thereby obtaining a pulse signal generated at each minute rotation angle.

In the above embodiment, counting of the third number N3 is started from the time when counting of the first number Nlx is finished, but as shown by the broken line in FIG. 11(D), the second number Counting of the third number N3 may be started from the time when counting of N2 ends. In this case, the interrupt routine executed every time the count value of the first counter 30h matches the contents of the second register 30i is as shown in FIG.

In the above embodiment, the reference signal is generated only once per revolution, but as shown in FIG. 12, when igniting a multi-cylinder internal combustion engine, it is possible to generate the reference signal for each cylinder. It can also be done. In the example shown in FIG. 12, two inductor magnetic pole parts are provided on the rotor of the signal generator 2, and the signal Vp3. vp↑, Vp
a. Generate Vp2. Of these signals, 12
Signal Vp3. generated at 0 degree intervals. Vpl, and Vp2
are signals generated at 5 degrees before top dead center of the third cylinder, first cylinder, and second cylinder, respectively, and these signals are the pre-ignition signals for the third cylinder, first cylinder, and second cylinder. It is used as a signal and also as a reference signal for determining the ignition timing of the first to third cylinders.

Further, the signal Vpa generated between the signals Vpl and Vp2 is used to determine which cylinder should be ignited.

That is, when it is detected that the signal Vpa is generated, it is determined that the cylinder to be ignited next is the second cylinder.

When generating a reference signal for each cylinder in this way, the interrupt routine shown in FIG.
The main routine shown in FIG. 3 and the interrupt routines shown in FIGS. 4, 7, and 8 are executed as shown in the figure.

In this case, when the reference signal Vp3 is generated, the fourth
The interrupt routine shown in the figure is executed and pulse signals are counted by a first number N1. After counting the first number N1,
After executing the interrupt routine of FIG. 8 and saving the count value of the timer, a second number N2 is set in the second register to cause the pulse signal to be counted by the second number N2. After the second number N2 has been counted, the interrupt routine shown in FIG. 8 is executed again, the timer count value is saved, and the third
The number N3 is set in the third register, and the pulse signals are counted by the third number N3. While counting the third number, the rotational speed of the engine is determined from the difference between the end time T2 of counting the second number N2 and the end time T1 of counting the first number N1. The ignition timing measurement time is calculated based on. After the calculation of the third number N3 is completed, a flag indicating the cylinder to be ignited is set, and then the ignition timing measurement time is set in the second register. After completing the measurement of the ignition timing measurement time, the interrupt routine shown in FIG. 7 is executed to perform the ignition operation in the first cylinder.

Next, when the reference signal Vpi is generated, the interrupt routine of FIG. 4 is executed again, and then the interrupt routines of FIGS. 8 and 7 are executed to ignite the second cylinder.

Thereafter, from the time when the reference signal Vp2 is generated, the interrupt routine shown in FIG. 4 is executed again in order, and the same process as above is repeated to ignite the third cylinder.

In the case of the interrupt routine of FIG. 8, the second number N2
However, as shown by the broken line in Fig. 12, the counting of the third number N3 is started after the counting of the first number N1 is completed. Counting may also be started. In this case, the interrupt routine shown in FIG. 8 is changed as shown in FIG. 9.

The ignition timing control method and ignition timing control device to which the present invention can be applied are not limited to the above examples. For example, the ignition timing control method and ignition timing control device to which the present invention can be applied are not limited to the above examples. The present invention can also be applied to an ignition timing control method in which the ignition timing is determined by calculating the measurement time and measuring the ignition timing measurement time from a predetermined position.

In the above embodiment, the ignition timing is changed according to the opening degree of the throttle valve, but the present invention can also be applied to a case where the ignition timing is changed according to the rotational speed of the engine.

The ignition timing in the present invention may be determined using a predetermined calculation formula, and the ignition timing may be stored in advance in a storage device for various values of throttle valve opening and engine rotational speed. A method may also be used in which the ignition timing is read from a storage device according to the detected throttle valve opening degree or engine rotational speed.

In the above embodiment, the ignition energy storage capacitor 407 of the ignition circuit 4 is provided in common for the three cylinders, but a well-known capacitor discharge type ignition circuit in which an ignition energy storage capacitor is provided for each cylinder is used. You can also use In this case, each ignition energy storage capacitor is connected in series with the primary coil of each ignition coil, and each ignition energy storage capacitor and one of the ignition coils are connected in series.
Each thyristor is connected in parallel to the series circuit with the next coil.

Further, the ignition circuit is not limited to a capacitor discharge type circuit, but may be any type of ignition circuit as long as it is driven by a generator driven by the engine.

In the above embodiment, a situation occurs in which the throttle valve is opened widely immediately after the engine starting operation is performed, and the advance angle corresponding to the opening degree of the throttle valve is larger than the advance angle in the starting control mode. In such a case, if the start control mode is performed after the start of the engine is confirmed, the advance angle will be insufficient and the engine rotational speed will not increase as desired by the driver. In order to prevent such a situation from occurring, if it is detected that the opening of the throttle valve is greater than a predetermined value immediately after the engine starts, the steady state control is suddenly activated without starting the startup control mode. In some cases, the mode may be changed. The present invention can also be applied to the case where the starting control mode is selectively performed in accordance with the opening degree of the throttle valve immediately after starting.

[Effects of the Invention] As described above, according to the present invention, when the engine is started, the startup control mode is performed and then the steady state control mode is performed, and the output of the generator is changed for some reason during the steady operation state. When the output voltage of the generator recovers after the microcomputer has been reset due to a decrease in This has the advantage of increasing safety by preventing the engine rotational speed from suddenly increasing due to unexpected start-up control.

[Brief explanation of drawings]

Fig. 1 is a claim correspondence diagram showing the structure of the present invention, Fig. 2 is a block diagram schematically showing the structure of a device used in an embodiment of the present invention, and Figs. 3 to 7 are examples of the present invention. FIGS. 8 and 9 are flowcharts showing control algorithms of other embodiments of the present invention, and FIG. 10 shows a temporary decrease in engine rotational speed and generator output and A waveform diagram showing changes in the terminal voltage of the integrating capacitor as the output decreases; Fig. 1 is a diagram showing the signal waveform and counting operation when following the flowcharts in Figs. 3 to 7; Fig. 12; 13 is a diagram showing signal waveforms and counting operations when following the flowcharts of FIGS. 8 and 9, and FIG. 13 is a diagram showing instantaneous rotational speed fluctuations of the engine. DESCRIPTION OF SYMBOLS 1... Internal combustion engine, 2... Alternator, 3-... Power supply circuit, 4... Ignition circuit, 5... Ignition timing control device, 6... Reset means, 7... Preliminary ignition signal supply circuit, 8... Starting control means, 9... Steady state control means, 10... Throttle sensor, 11... Charging circuit,
12... Integral conde Figure 5 Figure 6 Figure 8rSZJ

Claims (1)

[Scope of Claims] An alternating current generator driven by an internal combustion engine, a power supply circuit that rectifies the output of the generator to output a DC voltage, and an alternating current generator driven by an internal combustion engine; an ignition circuit that generates a high voltage for ignition; an ignition timing control device that controls the timing of applying an ignition signal to the ignition circuit by a microcomputer driven by the output of the power supply circuit; reset means for resetting the ignition timing control device to an initial state when it is detected that the voltage has become lower than a specified level for operating the computer; and the ignition timing control device when the output voltage of the power supply circuit is lower than the specified level. and an ignition signal supply circuit that supplies an ignition signal to the ignition circuit from another system, the ignition timing control device controlling the ignition timing for a set time to increase the rotational speed of the engine when starting the internal combustion engine. The engine has a starting control means for performing a starting control mode in which the ignition timing is advanced by a predetermined amount, and a steady state control means for performing a steady state control mode in which the ignition timing is controlled according to predetermined control conditions. In the ignition system for an internal combustion engine, the integral capacitor is charged by the power supply circuit at a predetermined time constant, the discharge circuit discharges the integral capacitor at a predetermined time constant, and the ignition timing control device starts operating. When the terminal voltage of the integrating capacitor is detected and the terminal voltage is less than a set value, the control operation of the ignition timing control device is started from the starting control mode, and after the starting control mode ends, the The ignition timing control device operates so as to shift to a steady state control mode, and to start from the steady state control mode without performing the starting control mode when it is detected that the terminal voltage of the integrating capacitor is equal to or higher than a set value. 1. An ignition device for an internal combustion engine, comprising: mode control means for controlling a mode at the time of starting.