JPH09112332A - Deciding method for rotation speed of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a deciding method for a rotation speed to decide whether the rotation speed of an engine is decreased to a value at which the output pulse of a signal generator to provide information on the rotation speed of an internal combustion engine can not exceed a threshold. SOLUTION: Each time the output waveform of an exciter coil 2 arranged in a magnet generator attached to an internal combustion engine attains a zero point, a timing signal Vp1 is generated. By deciding whether the period of the timing signal Vp1 is longer than or shorter than a reference time corresponding to a set rotation speed, it is decided whether the rotation speed of an engine is lower or higher than a set rotation speed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for determining the rotational speed of an internal combustion engine, which determines whether or not the rotational speed of the internal combustion engine exceeds a set rotational speed.

[0002]

2. Description of the Related Art In an internal combustion engine, when a microcomputer is used to control various controlled objects such as an ignition device, a fuel injection device, an exhaust control valve for adjusting exhaust timing, information on the rotational speed of the internal combustion engine is used. Need to be given to the controller.

For example, when controlling the ignition position of the engine, the rotational speed of the engine is detected, and the time required for the engine to rotate from the reference position to the ignition position at that rotational speed is calculated as the ignition position measurement time. To do. Then, the ignition position measurement time that has already been calculated when the reference position is detected is set in the ignition position measurement timer to start the measurement, and the ignition is started when the timer completes the measurement of the ignition position measurement time. I am trying to make it work.

Generally, in a control device for an internal combustion engine which controls various controlled objects by using a microcomputer, an inductor type signal generator which rotates in synchronization with the internal combustion engine and generates a pulse signal at a predetermined rotational angle position is provided. By providing a pulse signal obtained from the signal generator, information indicating a specific rotation angle position of the engine and information for determining a cylinder to be ignited are obtained, and the signal generator is generated. The rotation speed of the engine is detected from the pulse generation interval.

FIG. 8 (A) shows an example of the waveform of a pulse signal generated by an inductor-type signal generator with respect to the engine rotation angle θ. In this example, while the engine makes one revolution, Further, the negative pulse signal Vs1 and the positive pulse signal Vs2 are generated once each. In this case, for example, the pulse signal V
The position where s1 is generated is the maximum advance position of the engine and the pulse signal V
If the generation position of s2 is set as the minimum advance position, by detecting the pulse signals Vs1 and Vs2 respectively, it is possible to obtain information that the rotational angle position of the engine matches the maximum advance position and the minimum advance position, respectively. You can Further, one of the generation positions of these pulse signals can be used as a reference position for starting the measurement of the ignition position, and by measuring the generation interval Tn of the pulse signals Vs1 and Vs2, it is possible to obtain information on the engine speed. You can

The output pulse of the signal generator is converted into a signal having a waveform which can be recognized by the microcomputer by a predetermined waveform shaping circuit and then input to the input port of the microcomputer. In order to prevent a malfunction due to noise, a waveform shaping circuit is generally configured to recognize only an input pulse exceeding a predetermined threshold level as an output pulse of a signal generator.

[0007]

Since the inductor type signal generator cannot generate such a high voltage, the pulse signal wave obtained from the signal generator is generated when the engine speed is extremely low. In some cases, the high value drops significantly and becomes a level that the waveform shaping circuit cannot recognize. When the level of the pulse signal generated by the signal generator becomes a level that cannot be recognized by the waveform shaping circuit, the microcomputer cannot calculate the rotation speed, and the level of the pulse signal becomes a level that cannot be recognized. Various types of control will be performed using the previously calculated rotational speed data, making it impossible to perform appropriate control in accordance with the actual rotational speed of the engine.

In particular, as shown in FIG. 8 (B), when the engine is operating at high speed while maintaining a predetermined rotation speed N [rpm], as shown at the right end of FIG. Speed N
Is suddenly lowered, and when the output pulse of the signal generator becomes a level that cannot be recognized, the rotational speed data calculated during high-speed operation will be used as is for control at extremely low speeds. There is a risk of unfavorable conditions such as engine stoppage or damage.

In order to prevent such a situation from occurring, the lower limit value of the rotation speed at which the signal generator generates a pulse signal of a level recognizable by the waveform shaping circuit (signal input circuit of the microcomputer) is set. As a result, it is necessary to be able to determine whether or not the rotation speed of the engine exceeds the set rotation speed. If it is possible to determine whether or not the engine rotation speed exceeds the set rotation speed, when the rotation speed is determined to be less than or equal to the set rotation speed, various control targets corresponding to the rotation speed Since it is possible to take measures such as stopping the control and making the control amount constant (for example, fixing the ignition position to a fixed position suitable for extremely low speeds), the data of the rotation speed that greatly differs from the actual rotation speed can be obtained. It is possible to prevent improper control based on the above.

An object of the present invention is to provide a method for determining the rotational speed of an internal combustion engine, which can determine whether or not the rotational speed of the internal combustion engine exceeds a set rotational speed.

[0011]

The present invention is a method for determining the rotational speed of an internal combustion engine, which determines whether or not the rotational speed of the internal combustion engine exceeds a set rotational speed. In the present invention,
A specific phase portion appearing at equal angular intervals is detected from the waveform of the AC voltage induced in the magneto coil of the magneto generator driven by the internal combustion engine, and a timing signal is generated each time the specific phase portion is detected. .

The magneto-generator comprises a magnet rotor having a field structure formed by attaching a permanent magnet to a rotor yoke, and an iron core having a magnetic pole portion facing the magnetic poles of the magnet rotor, and a generator coil wound around the iron core. In this AC generator, the magnet rotor is attached to the output shaft of the engine, and the stator is attached to the case of the engine. An alternating voltage having a frequency proportional to the rotation speed of the engine is induced in the stator coil.

The "specific phase portions appearing at equiangular intervals" in the waveform of the output voltage of the magneto generator are zero cross points, peak points, points at which the output voltage reaches a predetermined threshold level, and the like. The timing signal generated by detecting this specific phase portion becomes a signal generated at constant angular intervals, and the generation period thereof changes in inverse proportion to the rotational speed of the engine.

In the method of the present invention, it is judged whether or not the generation cycle of the timing signal exceeds a reference time set to a length corresponding to the set rotational speed of the internal combustion engine, and the generation cycle of the timing signal is determined. Is determined to be equal to or longer than the reference time, it is determined that the rotation speed of the internal combustion engine is less than or equal to the set rotation speed, and the rotation of the internal combustion engine is determined when the generation cycle of the timing signal is shorter than the reference time. It is determined that the speed exceeds the set rotation speed.

In order to determine whether or not the generation cycle of the timing signal exceeds the reference time, for example, every time the timing signal is generated, the reference time set to a length corresponding to the set rotation speed is measured. Is started and a measurement end signal is generated when the measurement of the reference time is completed. Then, each time each timing signal is generated, it is determined whether or not a measurement end signal indicating the end of the measurement of the reference time started by the previous timing signal is generated,
When it is determined that the measurement end signal is generated, it is determined that the rotation speed of the internal combustion engine is less than or equal to the set rotation speed, and when it is determined that the measurement end signal is not generated, the rotation speed of the internal combustion engine is It may be determined that the set rotational speed is exceeded.

As a method of determining whether or not the timing signal generation cycle exceeds the reference time, the count value of the free-run counter is read every time the timing signal is generated, and the previous timing signal is generated. After that, the count value counted by the free-run counter is calculated as the rotation speed determination count value between the time when this timing signal is generated, and the rotation speed determination count value is equal to or greater than the reference value corresponding to the set rotation speed. When it is determined that the rotation speed is less than or equal to the set rotation speed, and when the rotation speed determination count value is determined to be smaller than the reference value, the rotation speed exceeds the set rotation speed. It is also possible to adopt a method of determining

A relatively large AC voltage is induced in the magneto coil of the magneto generator even when the engine speed is extremely low. Therefore, even when the engine output speed of the inductor-type signal generator drops to a level that cannot be recognized by the waveform shaping circuit, even when the engine is operating at extremely low speeds, the zero crossing is observed from the waveform of the AC voltage induced in the generator coil of the magnet generator. It is possible to easily detect a specific phase portion such as a point or a peak point, and it is possible to obtain a timing signal generated at a constant angular interval by detecting the specific phase portion. When the timing signal generated at a constant angular interval is obtained, the generation cycle of the timing signal is inversely proportional to the rotation speed of the engine, so the generation cycle of the timing signal is longer than the reference time corresponding to the set value of the rotation speed. By determining whether the engine speed is short or not, it is possible to detect whether or not the engine speed is equal to or lower than a set value.

As described above, according to the present invention, it is possible to detect that the rotation speed has decreased to a region in which the output pulse of the signal generator has an unrecognizable level, so that the rotation speed different from the actual rotation speed is detected. It is possible to prevent the internal combustion engine from being controlled based on the speed data.

The generator coil used to generate the timing signal includes an exciter coil used to charge a capacitor of a capacitor discharge type ignition device, a charge coil used to charge a battery, and the like.
It is preferable to use a coil having a relatively large number of turns.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an example of the configuration of an apparatus used for carrying out the rotation speed determination method of the present invention.
In the figure, reference numeral 1 is a capacitor discharge type ignition circuit, and 2 is an exciter coil provided in a magneto generator attached to an internal combustion engine. The illustrated ignition circuit 1 includes an ignition coil IG and an ignition energy storage capacitor C1 provided on the primary side of the ignition coil and charged to one polarity through a diode D1 by the positive half cycle output voltage of the exciter coil 2. And a discharge thyristor Th which is provided to discharge the electric charge of the capacitor C1 through the primary coil of the ignition coil IG when conducting, and an ignition plug P attached to the cylinder of the engine. The induced voltage of the secondary coil is applied to the spark plug P.

The induced voltage of the exciter coil 2 is input to the zero-cross detection circuit 3, and the output of the zero-cross detection circuit is the CPU 4 of the microcomputer constituting the control device.
Is input to the input port A1 of the. A signal generator 5 as shown in FIG. 2 is provided to obtain the rotation angle information and the rotation speed information of the internal combustion engine. Signal generator 5 shown
Is a rotor 5 provided so as to rotate synchronously with the internal combustion engine.
01 and a signal generator 502 that generates a signal voltage having a pulse waveform in response to a change in magnetic flux generated by the rotor 501. The rotor 501 is composed of a rotating body 503 made of a ferromagnetic material and a reluctor 504 formed on the outer periphery thereof. As a rotor of a magneto generator attached to an internal combustion engine, a flywheel magnet rotor in which a permanent magnet is attached to the inner circumference of a peripheral wall portion of a flywheel formed in a cup shape is often used. When a magnet rotor is used, the flywheel is used as the rotating body 503, and the reluctor 504 is formed on the outer peripheral surface of the peripheral wall portion of the flywheel or the outer peripheral surface of the boss portion, thereby the rotor 501 of the signal generator. Can be configured.

The signal emitting electrons 502 are arranged such that the magnetic pole portion 50 is opposed to the surface of the rotor 501 on which the reluctor 504 is provided.
A mounting portion provided on a case, a cover, or the like of an internal combustion engine, which includes an iron core 505 having a tip 5a, a signal coil 506 wound around the iron core 505, and a permanent magnet 507 magnetically coupled to the iron core 505. It is fixed to.

In the signal generator 5 described above, the permanent magnet 507 is passed through the permanent magnet 507, the iron core 505, the rotor 501, and the mounting portion provided on the case or cover of the internal combustion engine.
7 is formed, and when the reluctor 502 of the rotor 501 starts facing the magnetic pole portion 505a of the iron core 505 and when the facing ends, the magnetic resistance of the magnetic path changes to cause the iron core 505. Changes in magnetic flux occur within
Due to these changes in magnetic flux, pulse signals Vs1 and Vs2 having different polarities are induced in the signal coil 506. The pulse signals Vs1 and Vs2 are generated at fixed positions determined by the positional relationship between the rotor 501 and the signal-generating electrons 502 and the polar arc angle of the reluctor 504. The generation positions of the pulse signals Vs1 and Vs2 are set so as to coincide with a specific position, for example, the maximum advance position and the minimum advance position (maximum retard position) of the ignition position of the internal combustion engine. The rotation angle position information is captured. Further, from the time from the generation of the pulse signal Vs1 to the generation of the pulse signal Vs2, or the time from the generation of the pulse signal Vs1 or Vs2 to the generation of the next pulse signal Vs1 or Vs2, the rotational speed of the internal combustion engine Information is captured.

The pulse signal V generated by the signal coil 506
s1 and Vs2 are C through the waveform shaping circuits 6 and 7, respectively.
It is applied to the input ports A2 and A3 of the PU. The waveform shaping circuits 6 and 7 send the pulse signals Vs1 and Vs2 to the CPU.
Is a circuit for shaping into a waveform that can be recognized by the CPU, and when the pulse signals Vs1 and Vs2 each reach a predetermined threshold level, a signal indicating that each pulse signal is generated is given to the CPU. .

The CPU 4 calculates the ignition position of the engine based on the rotational speed information obtained from the pulse signals Vs1 and Vs2,
Output port Bo when the calculated ignition position is detected
To the gate of the thyristor Th of the ignition circuit 1 from which an ignition signal (signal for triggering the thyristor) Vi is given.

In the ignition circuit 1, the capacitor C1 is charged to the polarity shown in the positive half cycle of the AC voltage generated by the exciter coil 2. When an ignition signal is applied to the gate of the thyristor Th, the thyristor becomes conductive, so that the electric charge of the capacitor C1 is discharged through the thyristor Th and the primary coil of the ignition coil IG, and the secondary coil of the ignition coil has a high ignition voltage. Voltage is generated. Since this high voltage is applied to the spark plug P, a spark is generated in the spark plug and the engine is ignited.

The CPU 4 also calculates a control amount of a controlled object other than the ignition device based on various control conditions, and outputs control signals from its output ports B1 to Bn to various control circuits H1 to Hn. The control circuits H1 to Hn are circuits for driving a controlled object such as a fuel injection device that supplies fuel to the internal combustion engine and an exhaust valve that adjusts the exhaust timing of the internal combustion engine. The control amount (fuel injection time, exhaust valve opening, etc.) of each controlled object is controlled by supplying a drive current to the controlled object. In addition to the pulse signal obtained from the signal coil 506, the CPU 4 outputs the output of a sensor for detecting control conditions (ambient temperature, atmospheric pressure, etc.) necessary for controlling each control target as necessary, to a predetermined interface. However, these are not shown.

As shown in FIG. 5A, the exciter coil 2 has an AC voltage V that changes in synchronization with the rotation of the internal combustion engine.
e is output. The zero-cross detection circuit 3 detects a zero point generated when the AC voltage output by the exciter coil 2 shifts from a positive half cycle to a negative half cycle and a zero point when the negative half cycle shifts to a positive half cycle. Then, as shown in FIG. 5B, the time t1 at which the zero point occurs
, T2, ... Generates a detection signal Vp having a pulse waveform that falls to zero level. The CPU 4 recognizes each falling edge of the detection signal Vp supplied from the zero-cross detection circuit 3 as a timing signal Vp1 and detects each zero point. The series of timing signals Vp1, Vp1, ... Are signals generated at equal angular intervals, and the generation cycle of these timing signals changes in inverse proportion to the rotational speed of the internal combustion engine.

In this example, the zero-cross detection circuit 3 constitutes a timing signal generation circuit.

The exciter coil 2 outputs a relatively large AC voltage even when the engine speed is extremely low.
Therefore, even when the output pulse of the inductor-type signal generator 5 is reduced to a level that cannot be recognized by the waveform shaping circuits 6 and 7, the zero point is detected from the waveform of the AC voltage induced in the exciter coil 2 even at an extremely low speed of the engine. It can be easily detected, and by detecting the zero point, the timing signals Vp1, Vp1, ... Generated at constant angular intervals can be reliably obtained.

In the present invention, the timing signals Vp1,
By determining whether the cycle of Vp1, ... Is shorter or longer than the reference time corresponding to the set rotational speed, it is determined whether the rotational speed of the internal combustion engine exceeds the set rotational speed. The set rotation speed is set to a lower limit value of the rotation speed at which the signal generator 5 generates a pulse signal of a level (threshold level) that can be recognized by the waveform shaping circuits 6 and 7 or a value in the vicinity thereof. Set the rotation speed to Ns [rpm],
When the generation interval of the timing signal is α degrees, the reference time To corresponding to the set rotation speed is given by the following formula.

To = (60 / Ns) × (α / 360) (1) According to the present invention, the output pulse of the signal generator becomes equal to or lower than the threshold level (a level recognizable by the control device). Even when the engine is extremely low speed, it is possible to obtain the timing signal and determine whether the engine rotation speed is equal to or lower than the set rotation speed Ns. Therefore, it is possible to obtain the rotation speed information from the output of the signal coil 506. It becomes possible to prevent the CPU 4 from controlling the internal combustion engine on the basis of the rotation speed data different from the actual rotation speed at the extremely low speed below the set rotation speed Ns.

There are various methods for determining whether the cycle of the timing signal exceeds the reference time. When a microcomputer is used as the control device, a timer provided in the microcomputer is used. A decision can be made. The main part of the algorithm of the program executed by the microcomputer when determining whether the cycle of the timing signal is shorter or longer than the reference time using the timer is shown in FIGS. 3 and 4. 3 is an interrupt routine executed by using the timing signals Vp1, Vp1, ... As external interrupt signals. In this interrupt routine, a flag (as will be described later, this flag indicates that the timer has completed measuring the reference time To). Is set to "1".) Is "1", and if the flag is "1", the current engine speed N is less than or equal to the set engine speed Ns. Then, a detection signal indicating that N ≦ Ns is output. When the flag is not "1", it is determined that the rotation speed N exceeds the set rotation speed Ns, and a detection signal indicating that N> Ns is output. Detection signal indicating N ≦ Ns or N>
After generating the detection signal indicating Ns, the flag is set to "0", and the reference time To is set in the timer (or counter).
Is set to start measuring the reference time. afterwards,
After enabling the internal interrupt, the process returns to the main routine (not shown). The timer generates a measurement end signal as an internal interrupt signal when it finishes measuring the reference time To. FIG. 4 is an internal interrupt routine that is executed each time the timer generates a measurement end signal (internal interrupt signal). In this interrupt routine, after setting the flag to “1”, the internal interrupt (the routine of FIG. Execution) and return to the main routine.

In this example, according to the routines shown in FIGS. 3 and 4, whether or not the measurement end signal indicating the end of the measurement of the reference time started by the previous timing signal is generated every time the timing signal is generated. When it is determined that the measurement end signal is generated, it is determined that the rotation speed of the internal combustion engine is less than or equal to the set rotation speed, and when it is determined that the measurement end signal is not generated, the internal combustion engine A rotation speed determination means for determining that the rotation speed of is higher than the set rotation speed is realized. Further, the determination means, the timer, and the zero-cross detection circuit 3 (timing signal generation circuit) constitute a rotation speed detection device.

The method of determining the rotation speed, which is executed according to the algorithm shown in FIGS. 3 and 4, is as follows. When the exciter coil 2 generates the AC voltage shown in FIG. 5 (A) due to the rotation of the internal combustion engine, the timing signal Vp1 is generated as shown in FIG. 5 (B) every time the engine rotates by a certain angle. When the timing signal Vp1 is generated, the interrupt routine of FIG. 3 is executed, so that the reference time To is set in the timer and the measurement of the reference time is started. FIG.
(C) shows the operation of the timer when the rotation speed of the engine is less than or equal to the set rotation speed. The rising edge of the rectangular wave shown in the figure indicates the start time of the measurement operation of the timer, and the rising edge of the rectangular wave. The fall indicates the end time of the measurement operation.

When the engine rotation speed N is equal to or lower than the set rotation speed, as shown in FIGS. 5 (B) and 5 (C),
Since the generation cycle of the timing signal is longer than the reference time To, the timer finishes the measurement operation between the generation of each toning signal and the generation of the next timing signal, and the measurement end signal Vq. Occurs. Therefore, in this state, when the measurement end signal Vq is generated, the interrupt routine of FIG. 4 is executed and the flag is set to "1". When the flag is set to "1", it is determined that the rotation speed N is equal to or lower than the set rotation speed Ns when the timing signal Vp1 is generated and the interrupt routine of FIG. 3 is executed.

On the other hand, when the engine rotation speed is higher than the set rotation speed, as shown in FIGS. 6A and 6B, the frequency of the AC voltage Ve increases and the cycle of the timing signal Vp1 increases. Becomes shorter than the reference time To, as shown in FIG. 6C, after each timing signal Vp1 is generated and the timer starts the measurement operation of the reference time To, before the measurement operation is finished. Since the next timing signal is generated and a new reference time To is set in the timer, the timer cannot finish measuring the reference time To, and as shown in FIG. It becomes impossible to generate the measurement end signal Vq. In this state,
When the interrupt routine of FIG. 3 is executed, it is determined that the rotation speed N exceeds the set rotation speed Ns because the flag is “0”.

FIG. 7 shows a case where the engine is suddenly decelerated while it is rotating at a high speed, and the engine is stopped immediately after the timing signal Vp1 is generated at time t4. In this case, the timer ends the measurement operation at the time when the reference time To has elapsed from the time t4, and the measurement end signal Vq is generated as shown in FIG. 6 (D). In this case, since the timing signal is not generated after the measurement end signal Vq is generated, the interrupt routine of FIG. 3 is not executed and it is not determined whether the rotation speed is equal to or lower than the set rotation speed. Therefore, the microcomputer tries to perform various controls by using the data of the rotational speed calculated while the engine is rotating at high speed. In order to avoid such a situation, it is necessary to separately provide means for detecting that the internal combustion engine has stopped.

To detect the stop of the internal combustion engine, for example,
After the measurement end signal Vq is generated, it may be detected that the timing signal is not generated. To detect that the timing signal does not occur after the measurement end signal is generated, for example, a timer for engine stop detection that is reset each time the timing signal is generated and interrupts the counting operation is provided, and the measurement end signal is generated. Every time the engine is started, a set time set slightly longer than the maximum value of the cycle of the timing signal at the time of starting the engine is set in the engine stop detection timer to measure the set time, and the measurement is performed. A detection signal indicating that the engine has stopped may be generated when the operation ends.

Each time a timing signal is generated, the set time is set in the engine stop detection timer to start its measurement operation, and the engine is stopped when the engine stop detection timer finishes the measurement operation. You may make it generate | occur | produce the detection signal which shows that.

Further, a counter is provided so that the count value overflows when the clock pulse is counted for a set time which is set to be slightly longer than the generation period of the timing signal at the time of starting the engine. The counter may be reset each time it occurs and the counting operation may be started from the beginning, and a detection signal indicating that the engine has stopped may be generated when the counter overflows.

In the above description, the timer is used to determine whether or not the cycle of the timing signal exceeds the reference time. However, after counting the clock pulse to a predetermined count value, the count is returned to zero. If the microcomputer is equipped with a free-run counter that repeats the operation, the count value of the free-run counter is read every time the timing signal is generated, and the timing signal of this time is generated after the previous timing signal is generated. The count value counted by the free-run counter is calculated as the rotation speed judgment count value until the occurrence of the rotation speed, and it is checked whether this rotation speed judgment count value is larger or smaller than the reference value corresponding to the set rotation speed. Thus, it may be determined whether or not the rotation speed exceeds the set rotation speed. In this case, when it is determined that the calculated rotation speed determination count value is equal to or higher than the reference value, it is determined that the rotation speed is equal to or lower than the set rotation speed, and the rotation speed determination count value is higher than the reference value. When it is determined to be small, it is determined that the rotation speed exceeds the set rotation speed.

As described above, according to the present invention, it is possible to detect that the rotation speed of the engine has dropped below the set rotation speed and the output signal of the signal generator cannot be recognized. It is possible to prevent improper control from being performed by rotational speed data that is different from the actual rotational speed at an extremely low speed. For example, taking the control of the ignition position as an example, when the engine rotation speed is higher than the set rotation speed and the rotation angle information and the rotation speed information can be obtained from the output pulse of the signal generator 5, the signal generation CPU 4 based on rotation angle information and rotation speed information obtained from the output pulse of machine 5.
By calculating the ignition position at each rotation speed and applying an ignition signal to the ignition circuit 1 at the calculated ignition position, the ignition position of the engine can be accurately controlled with respect to the rotation speed. Further, when the engine rotation speed becomes equal to or lower than the set rotation speed and the rotation angle information and the rotation speed information cannot be obtained from the signal generator 5, a predetermined ignition position suitable for a low speed is set as a predetermined ignition position. By fixing the ignition position to the position and applying the ignition signal to the ignition circuit 1 at the fixed ignition position, it is possible to prevent erroneous control based on the rotational speed data at the time of medium and high speed at extremely low speed. it can.

In the above example, a circuit for detecting the zero point from the waveform of the output voltage of the exciter coil is provided, and the timing signal is generated each time the zero point is detected. However, the timing signal is the output of the magnet generator. It suffices to detect and generate a specific phase portion that appears at each constant rotation angle among the respective portions of the voltage waveform, and it is not always necessary to detect the zero point and generate the timing signal. For example,
A peak detection circuit for detecting the peak point of the output voltage of the exciter coil may be provided and a timing signal may be generated each time the peak detection circuit detects the peak point.

Further, by detecting a specific phase portion of the output waveform of a power generation coil other than the exciter coil, for example, a charging coil provided for charging a battery, timing signals generated at equal angular intervals can be obtained. May be.

The preferred embodiments of the present invention have been described above. The main aspects of the invention disclosed in the present specification are as follows.

(1) When the rotational speed exceeds the set rotational speed, a pulse signal that exceeds the threshold level is output. The rotational speed information and the rotational angle information are obtained from the output pulse signal of the generator. A rotation speed determination method for determining whether or not a rotation speed of an internal combustion engine including a control device for controlling a control target exceeds the set rotation speed, the generator coil of a magneto generator driven by the internal combustion engine A specific phase portion appearing at equal angular intervals is detected from the waveform of the AC voltage induced in the, and a timing signal is generated every time the specific phase portion is detected, and the generation cycle of the timing signal is the set rotation speed. It is determined whether or not the reference time set to the length corresponding to the above is exceeded, and when it is determined that the generation cycle of the timing signal is equal to or longer than the reference time, When it is determined that the rotation speed is less than or equal to the set rotation speed, and the generation cycle of the timing signal is determined to be shorter than the reference time, it is determined that the rotation speed of the internal combustion engine exceeds the set rotation speed. A method for detecting the rotational speed of an internal combustion engine, which is characterized.

(2) A signal that outputs a pulse signal exceeding the threshold level when the rotation speed exceeds the set rotation speed. The rotation speed information and the rotation angle information are obtained from the output pulse signal of the signal generator, and various kinds of information are obtained. A rotation speed determination method for determining whether or not the rotation speed of an internal combustion engine having a control device for controlling a controlled object exceeds the set rotation speed, wherein a magneto coil of a magneto generator driven by the internal combustion engine A specific phase portion that appears at equal angular intervals is detected from the waveform of the induced AC voltage, a timing signal is generated each time the specific phase portion is detected, and the set rotation is generated each time the timing signal is generated. The measurement of the reference time set to the length corresponding to the speed is started, the measurement end signal is generated when the measurement of the reference time is completed, and each timing signal is generated. It is determined whether or not a measurement end signal indicating the end of the measurement of the reference time started by the previous timing signal is generated, and when it is determined that the measurement end signal is generated, the rotation speed of the internal combustion engine Is less than or equal to the set rotational speed, and when it is determined that the measurement end signal is not generated, the rotational speed of the internal combustion engine is determined to exceed the set rotational speed. Speed judgment method.

(3) A signal that outputs a pulse signal that exceeds the threshold level when the rotation speed exceeds the set rotation speed. The rotation speed information and the rotation angle information are obtained from the output pulse signal of the generator. A rotation speed determination method for determining whether or not the rotation speed of an internal combustion engine having a control device for controlling a controlled object exceeds the set rotation speed, wherein a magneto coil of a magneto generator driven by the internal combustion engine A specific phase portion that appears at equal angular intervals is detected from the waveform of the induced AC voltage, a timing signal is generated each time the specific phase portion is detected, and the set rotation is generated each time the timing signal is generated. Set a reference time set to a length corresponding to the speed to a timer to start measurement of the reference time, and generate a measurement end signal when the measurement of the reference time ends, Each time each timing signal is generated, it is determined whether or not a measurement end signal indicating the end of measurement of the reference time started by the previous timing signal is generated, and it is determined that the measurement end signal is generated. When it is determined that the rotation speed of the internal combustion engine is less than or equal to the set rotation speed, and when the measurement end signal is not generated, it is determined that the rotation speed of the internal combustion engine exceeds the set rotation speed. And a method for determining the rotation speed of an internal combustion engine.

(4) A signal that outputs a pulse signal that exceeds the threshold level when the rotation speed exceeds the set rotation speed. The rotation speed information and the rotation angle information are obtained from the output pulse signal of the generator. A rotation speed determination method for determining whether or not the rotation speed of an internal combustion engine having a control device for controlling a controlled object exceeds the set rotation speed, wherein a magneto coil of a magneto generator driven by the internal combustion engine A specific phase portion that appears at equal angular intervals is detected from the waveform of the induced AC voltage, a timing signal is generated each time the specific phase portion is detected, and a free-run counter is generated each time the timing signal is generated. Read the count value of and rotate the count value counted by the free-run counter between the timing signal generated last time and the timing signal generated this time. Calculated as a count value for speed judgment,
When it is determined that the rotation speed determination count value is equal to or higher than the reference value corresponding to the set rotation speed, it is determined that the rotation speed is equal to or lower than the set rotation speed, and the rotation speed determination count value is the reference value. A method for determining a rotation speed of an internal combustion engine, comprising determining that the rotation speed exceeds a set rotation speed when it is determined that the rotation speed is smaller than a value.

(5) A signal that outputs a pulse signal that exceeds the threshold level when the rotation speed exceeds the set rotation speed. The rotation speed information and the rotation angle information are obtained from the output pulse signal of the generator. A rotation speed determination method for determining whether or not a rotation speed of an internal combustion engine including a control device for controlling a control target exceeds the set rotation speed, the generator coil of a magneto generator driven by the internal combustion engine A specific phase portion appearing at equal angular intervals is detected from the waveform of the AC voltage induced in the, and a timing signal is generated every time the specific phase portion is detected, and the generation cycle of the timing signal is the set rotation speed. It is determined whether or not the reference time set to the length corresponding to the above is exceeded, and when it is determined that the generation cycle of the timing signal is equal to or longer than the reference time, It is determined that the rotation speed is equal to or lower than the set rotation speed, and it is determined that the rotation speed of the internal combustion engine exceeds the set rotation speed when the generation cycle of the timing signal is determined to be shorter than the reference time, A method for detecting a rotation speed of an internal combustion engine, comprising: determining that the internal combustion engine has stopped when a generation cycle of a timing signal exceeds a set time.

[0052]

As described above, according to the present invention, it is possible to detect a specific phase portion from the output voltage of the magneto generator showing a sufficiently recognizable level even when the rotation speed of the internal combustion engine is extremely low. , The rotation speed is lower or higher than the set rotation speed by obtaining the timing signal generated at a constant angular interval and checking whether the cycle of the timing signal is longer or shorter than the reference time corresponding to the set rotation speed. Since the determination is made as to whether or not the output pulse of the signal generator has decreased to an unrecognizable level, it is possible to reliably detect that the rotation speed has decreased and to provide the information to the control device. Therefore, when the control device controls the internal combustion engine based on the rotational speed data different from the actual rotational speed when the internal combustion engine is extremely low speed, it is possible to prevent an abnormal state from occurring.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a configuration example of an apparatus for carrying out a determination method of the present invention.

2 is a configuration diagram schematically showing a configuration of a signal generator used in the device of FIG. 1. FIG.

FIG. 3 is a flowchart showing a main part of an algorithm of a program executed when the determination method of the present invention is carried out using a microcomputer.

FIG. 4 is a flowchart showing another main part of the algorithm of the program executed when the determination method of the present invention is carried out using a microcomputer.

FIG. 5 is a diagram showing signal waveforms and timer operations of respective parts in a state where it is detected that the engine speed is lower than the set engine speed in the embodiment of the present invention.

FIG. 6 is a diagram showing signal waveforms and timer operations of respective parts in a state where it is detected that the rotation speed of the engine is higher than the set rotation speed in the embodiment of the present invention.

FIG. 7 is a diagram showing signal waveforms and timer operations of various parts when the engine suddenly stops from a state in which the engine is rotating at high speed, in an embodiment of the present invention.

FIG. 8 is a diagram showing an output pulse waveform of a signal generator and a change in rotation speed when the engine suddenly stops from a state in which it rotates at high speed.

[Explanation of symbols]

 1 Ignition circuit 2 Exciter coil 3 Zero cross detection circuit 4 CPU 5 Signal generator 501 Rotor 502 Signal generator

Claims (3)

[Claims] 1. A method of determining the rotational speed of an internal combustion engine for determining whether or not the rotational speed of the internal combustion engine exceeds a set rotational speed, the method comprising: A specific phase portion that appears at equal angular intervals from the waveform is detected, and a timing signal is generated each time the specific phase portion is detected, and the generation cycle of the timing signal has a length corresponding to the set rotation speed. It is determined whether or not the set reference time is exceeded, and it is determined that the rotation speed of the internal combustion engine is the set rotation speed or less when the generation cycle of the timing signal is determined to be the reference time or longer, A rotation speed of the internal combustion engine, characterized in that when the generation cycle of the timing signal is determined to be shorter than the reference time, the rotation speed of the internal combustion engine is determined to exceed the set rotation speed. Determination method. 2. A method for determining the rotational speed of an internal combustion engine for determining whether or not the rotational speed of the internal combustion engine exceeds a set rotational speed, the method comprising: A specific phase portion that appears at equal angular intervals is detected from the waveform, a timing signal is generated each time the specific phase portion is detected, and a length corresponding to the set rotation speed is generated each time the timing signal is generated. Start the measurement of the reference time set to the above, and generate a measurement end signal when the measurement of the reference time ends, and each time the timing signal is generated, the reference time of the reference time started by the previous timing signal is generated. It is determined whether or not a measurement end signal indicating the end of measurement is generated, and when it is determined that the measurement end signal is generated, the rotation speed of the internal combustion engine is less than or equal to the set rotation speed. When it is determined that the measurement end signal is not generated, it is determined that the rotation speed of the internal combustion engine exceeds the set rotation speed. 3. A method for determining the rotational speed of an internal combustion engine for determining whether or not the rotational speed of the internal combustion engine exceeds a set rotational speed, the method comprising: determining the AC voltage induced in a magneto coil of a magneto generator driven by the internal combustion engine. A specific phase portion that appears at equal angular intervals is detected from the waveform, a timing signal is generated each time the specific phase portion is detected, and the count value of the free-run counter is read every time the timing signal is generated. Then, the count value counted by the free-run counter from the generation of the previous timing signal to the generation of the current timing signal is calculated as the rotation speed determination count value, and the rotation speed determination count value is When it is determined that the rotation speed is equal to or higher than the reference value corresponding to the set rotation speed, the rotation speed is determined to be equal to or lower than the set rotation speed, and the rotation speed determination count value is equal to A method for determining a rotation speed of an internal combustion engine, comprising: determining that the rotation speed exceeds a set rotation speed when it is determined that the rotation speed is smaller than a reference value.