JP2004324516A - Ignition device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To surely detect that an output voltage in a power supply part becomes excessive, without being affected by a noise. <P>SOLUTION: The output voltage of the power supply part 1 for supplying a power supply voltage to an ignition circuit 3 is sampled by an electronic control unit 4, and the number in which the sampled voltage exceeds a control value is found as an over voltage detection number. When the over voltage detection number reaches a set value within a set detection time, abnormality occurring in the power supply part 1 is detected. When the abnormality occurring in the power supply part is detected, supply of an ignition signal to the ignition circuit 3 from the electronic control unit 4 is stopped to carry out misfire of the internal combustion engine, thereby reducing an engine speed. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an internal combustion engine ignition device driven by a rectified output of an AC generator driven by an internal combustion engine.
[0002]
[Prior art]
In a vehicle or ship driven by an internal combustion engine, an AC generator driven by the internal combustion engine, a rectifier circuit that converts the output of the generator into a DC output, and a battery that is charged by the output of the rectifier circuit; Is provided, and a power supply voltage is applied from the power supply unit to an electrical component such as an ignition circuit. The power supply unit usually has a regulator function for controlling the voltage across the battery so as to keep it below a limit value.
[0003]
In an internal combustion engine-driven vehicle or the like equipped with a power supply unit as described above, if the battery is removed during operation of the engine or an abnormality occurs in the regulator function of the power supply unit, the output voltage of the power supply unit rises and ignition occurs. A voltage higher than the rated voltage of the battery is applied to an electrical component such as a circuit.
[0004]
Therefore, when using the power supply unit as described above, high power, high power are used as electronic components that constitute the ignition circuit and the like in case the battery is removed during operation or when an abnormality occurs in the regulator. Although a pressure-resistant one was used, it was inevitable that the use of such a component would increase the cost of the ignition device.
[0005]
Therefore, as shown in Patent Document 1, a technique has been proposed in which an ignition operation of an engine is stopped when an abnormality such as removal of a battery is detected, and the engine is put into a misfire state.
[0006]
Patent Document 2 discloses a technique for stopping the operation of the ignition device when it is detected that the output voltage of the power supply unit is excessive.
[0007]
According to these prior arts, when an abnormality occurs in the power supply unit such as the output voltage of the power supply rising due to the battery being removed, etc., the engine is misfired and the rotational speed of the engine is reduced. Therefore, the output of the generator can be reduced, and the voltage applied to the ignition device or the like from the power supply unit can be made lower than the set value. Further, since the abnormality can be notified to the driver due to the decrease in the rotational speed of the engine, it is possible to prevent the engine from being continuously operated in a state where the abnormality has occurred.
[0008]
The ignition devices shown in Patent Document 1 and Patent Document 2 do not control the ignition timing using a microcomputer, but in an internal combustion engine provided with an electronic control unit that controls the ignition timing using a microcomputer. However, as in the ignition devices disclosed in Patent Document 1 and Patent Document 2, when the output voltage of the power supply unit exceeds the limit value, the operation of the ignition circuit is stopped to put the engine in a misfire state. ing. When such a control is performed using a microcomputer, the output voltage of the power supply unit is sampled at a constant cycle, and the operation of the ignition circuit is performed when the sampled voltage exceeds a preset limit value. I try to stop it. When performing protection control such as stopping the ignition operation when the sampling value of the output voltage of the power supply exceeds the limit value, the ignition operation is stopped immediately when it is detected that the sampling value exceeds the limit value. If this is done, the engine is misfired and its rotational speed decreases even when a sampling value of the output voltage exceeding the limit value is read by the microcomputer due to the intrusion of noise or surge voltage, which is not preferable. Therefore, in this type of ignition device currently used, protection control is performed such that the engine is misfired only when the sampling value of the output voltage of the power supply unit exceeds the limit value continuously detected a plurality of times. I am doing so.
[0009]
[Patent Document 1]
Japanese Unexamined Patent Publication No. 63-227961
[0010]
[Patent Document 2]
JP-A-2-2488631
[0011]
[Problems to be solved by the invention]
As described above, when it is made to perform protection control such as misfiring the engine when the sampling value of the output voltage of the power supply unit exceeds the limit value continuously several times, As shown below, when a ripple (pulsation waveform component) is included in the output voltage of the power supply unit in a state where an abnormality has occurred, there arises a problem that the abnormality cannot be accurately detected.
[0012]
When a battery is connected between the output terminals of the power supply unit, the capacitance of the battery is large, and the ripple component included in the output voltage of the power supply unit is absorbed by the battery. A ripple component does not appear between them, but when the battery is removed from the output terminal of the power supply unit, a ripple corresponding to the waveform obtained by rectifying the AC output of the generator appears between the output terminals of the power supply unit.
[0013]
FIG. 5 shows an example in which the full-wave rectified waveform of the output of the AC generator appears between the output terminals of the power supply unit with the battery removed from between the output terminals of the power supply unit. It shows an example of the result of sampling at a period of. FIG. 5C shows the voltage Eo of the full-wave rectified waveform appearing between the output terminals of the power supply unit with respect to time t. In this example, the magnet power generation having a 12-pole magnet rotor as a generator. The machine is used. FIG. 5A shows an operation of sampling the output voltage of the power supply unit, and shows that sampling is performed at the timing when each downward arrow is displayed. In this example, the rotational speed of the generator is 10,000 r / min (constant), and the sampling interval is 250 μsec.
[0014]
FIG. 5B shows the result of determining whether or not the sampling value exceeds the limit value Es when the limit value Es of the output voltage of the power supply unit is 18 [V]. Indicates a case where the output voltage is less than or equal to the limit value (normal case), and x indicates a case where the output voltage exceeds the limit value (overvoltage).
[0015]
In this example, it is assumed that the rated voltage of the battery connected between the output terminals of the power supply unit is 12 [V].
[0016]
As is apparent from FIG. 5, when it is determined that an overvoltage has occurred when it is detected that the sampling value exceeds the limit value a plurality of times (for example, twice) continuously, When the sampling interval is set as shown in FIG. 5A for the ripple voltage waveform shown in FIG. 5C, the overvoltage cannot be detected twice in succession, and thus an overvoltage has occurred. Nevertheless, there arises a problem that the protection operation is not performed.
[0017]
In order to prevent such a state from occurring, as shown in FIG. 6, it is conceivable to perform sampling at a sufficiently short interval with respect to a half-wave period of the output voltage Eo of the power supply unit. In the example shown in FIG. 6, the sampling interval is set to 50 μsec for the same output voltage waveform as that shown in FIG. In this way, if the sampling interval is set short, an overvoltage can be detected continuously twice or more, so that the overvoltage can be accurately detected. However, if the sampling interval is made too short, the overvoltage protection control is performed. For this reason, there is a problem that the time required for calculation processing for the engine becomes too long, and calculation processing necessary for controlling the ignition timing, such as calculation of engine speed and calculation of ignition timing, cannot be performed.
[0018]
If the sampling interval is too short, there is a problem that the probability of recognizing noise, surge, etc. as an overvoltage is increased.
[0019]
It is an object of the present invention to accurately detect that the output voltage of the power supply section has become excessive without excessively shortening the sampling interval, and to perform control for protecting the ignition circuit and the like from overvoltage. Another object of the present invention is to provide an internal combustion engine ignition device.
[0020]
[Means for Solving the Problems]
The present invention relates to a power supply unit having at least an alternator driven by an internal combustion engine and a rectifier circuit for converting the output of the alternator into direct current, and the output voltage of the power supply unit is supplied as a power source when an ignition signal is given. An ignition device for an internal combustion engine including an ignition circuit that generates a high voltage for ignition as a voltage, and an ignition timing control unit that controls a timing at which an ignition signal is supplied to the ignition circuit is intended.
[0021]
In the present invention, in order to achieve the above object, the power supply voltage sampling means for sampling the output voltage of the power supply section at a constant sampling interval, and the number of times the voltage sampled by the power supply voltage sampling means exceeds a limit value. An overvoltage detection count is obtained, and when the overvoltage detection count reaches a set value within the set detection time, a power supply abnormality detection means for detecting that an abnormality has occurred in the power supply section, and an abnormality in the power supply section by the power supply abnormality detection means There is provided a power failure time point fire control means for controlling the ignition circuit so as to reduce the rotational speed of the internal combustion engine or stop the internal combustion engine when it is determined that the engine has occurred.
[0022]
As described above, if an abnormality of the power supply unit is detected when it is detected that a voltage exceeding the limit value has been sampled more than the set number of times within the set detection time, the sampling interval of the output voltage of the power supply unit is excessively shortened. It is possible to accurately detect that an abnormality has occurred in the power supply unit without performing erroneous detection that the power supply unit is abnormal when an overvoltage is sampled due to noise, surge voltage, or the like.
[0023]
Therefore, as described above, when the voltage exceeding the limit value is sampled more than the set number of times within the set detection time, it is assumed that the power supply unit is abnormal, and the protection control is performed to reduce the rotation speed of the internal combustion engine or stop the engine. If the battery is removed or the regulator function of the power supply section is lost, and an abnormal voltage with a pulsating waveform appears in the output voltage of the power supply section, it is necessary for controlling the ignition timing, etc. From the sampling value of the output voltage of the power supply unit obtained at a sampling interval that does not affect the arithmetic processing, it is possible to reliably detect that an abnormality has occurred in the power supply unit and to accurately control the ignition circuit etc. from overvoltage. Can be done.
[0024]
In a preferred aspect of the present invention, when the power supply abnormality detection means determines whether or not the overvoltage detection count is 1 or more each time the sampling means samples the power supply voltage, the overvoltage detection count is 1 or more. Timer start means for starting the timer, timer measurement value determination means for determining whether or not the time measured by the timer exceeds the set detection time, and timer measurement if the time measured by the timer does not exceed the set detection time A sample voltage value comparison / determination unit that compares the voltage sampled by the power supply voltage sampling unit with a limit value when determined by the value determination unit; and a voltage value sampled by the sample voltage value comparison / determination unit exceeds the limit value Overvoltage detection frequency counting means for incrementing the overvoltage detection frequency by 1 when it is determined that the Overvoltage detection frequency determination means for determining that an abnormality has occurred in the power supply unit when the number of times of overvoltage detection reaches a set value in a state where it is determined that the time measured by the timer does not exceed the set detection time And reset means for resetting the timer to stop the time counting operation and reset the overvoltage detection count to 0 when the timer measurement value determination means determines that the time measured by the timer exceeds the set detection time. Is done.
[0025]
The power supply abnormality point fire control means can be configured to stop the operation of the ignition circuit generating the ignition high voltage while the abnormality of the power supply unit is detected.
[0026]
The power supply abnormality point fire control means can also be configured to intermittently stop the operation of the ignition circuit generating a high voltage for ignition while abnormality of the power supply unit is detected.
[0027]
The power supply abnormality point fire control means may be configured to retard the ignition timing of the internal combustion engine while the abnormality of the power supply unit is detected.
[0028]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0029]
FIG. 1 shows an example of the hardware configuration of an ignition device according to the present invention. In this embodiment, the internal combustion engine is a single cylinder. The ignition device shown in FIG. 1 includes a power supply unit 1, a battery 2 connected between output terminals of the power supply unit 1, a power supply terminal 3a to which an output of the power supply unit 1 is applied, and a control terminal to which an ignition signal Si is applied. 3b, using the output of the power supply unit 1 as a power supply voltage, and controlling the timing of applying an ignition signal to the ignition circuit 3 that generates a high voltage for ignition when the ignition signal Si is applied The electronic control unit 4 that performs the operation, the constant voltage power circuit 5 that converts the output voltage of the power supply unit 1 into a constant DC voltage suitable for driving the electronic control unit 4, and the voltage detection that detects the output voltage of the power supply unit 1. A high voltage for ignition obtained from the ignition circuit 3 is applied to a spark plug 7 attached to a cylinder of the engine.
[0030]
To explain each part in more detail, the power source unit 1 includes a magnet type AC generator 1A attached to an internal combustion engine (not shown), and a regulator (voltage adjustment) function that rectifies the AC output of the generator 1A and converts it into a DC output. And a rectifier circuit 1B. The rectifier circuit 1B includes a mixed bridge full-wave rectifier circuit composed of a diode and a thyristor, and a thyristor control circuit that controls the conduction angle of the thyristor so as to keep the output voltage of the rectifier circuit below a limit value. And a diode bridge full-wave rectifier circuit that full-wave rectifies the AC output of the generator 1A and a short-circuit regulator that short-circuits the output of the generator 1A when the output of the rectifier circuit exceeds a limit value. Known circuits can be used.
[0031]
The battery 2 is a secondary battery such as a lead storage battery, and is connected between the output terminals of the power supply unit 1 and charged by the output of the power supply unit 1.
[0032]
The ignition circuit 3 is configured to perform an ignition operation using a DC voltage as a power supply voltage. An ignition circuit driven by a DC power source is configured to block the primary current of the ignition coil that has flowed before the ignition timing at the ignition timing, so that a high voltage for ignition is applied to the secondary coil of the ignition coil. An ignition coil that uses a current interrupting ignition circuit to induce or discharges the charge of the ignition capacitor charged with the voltage obtained by boosting the output of the DC power source through the primary coil of the ignition coil at the ignition timing The secondary coil of the present invention employs a capacitor discharge type ignition circuit that induces a high voltage for ignition, and the present invention can be applied to any of these ignition circuits. In the embodiment, the ignition circuit 3 is a capacitor discharge type ignition circuit.
[0033]
The illustrated ignition circuit 3 includes a DC-DC converter 3A that boosts a DC voltage (usually 12 [V]) supplied from the power supply unit 1 through the power supply terminal 3a to a DC voltage of 200 tens of volts, an ignition coil 3B, A primary current control circuit 3C that causes a sudden change in the primary current of the ignition coil 3B at the ignition timing, using the DC voltage supplied from the converter 3A as a power supply voltage.
[0034]
The DC-DC converter 3A includes, for example, a step-up transformer in which a DC voltage supplied from the power supply unit 1 is applied to a primary coil via a chopper switch, an oscillator that generates a signal for turning on and off the chopper switch, and a chopper And a rectifier that rectifies the high voltage induced in the secondary coil of the step-up transformer when the switch is turned on and off. A power supply terminal 3a of the ignition circuit is derived from a power supply voltage input terminal of the DC-DC converter 3A.
[0035]
The primary current control circuit 3C includes an ignition capacitor Ci that is charged by the output voltage of the converter 3A, and the electric charge accumulated in the ignition capacitor Ci when the ignition signal Si is applied, and the primary coil of the ignition coil 3B. It has a well-known circuit configuration including a thyristor Th1 constituting a discharge switch provided to discharge through W1, and in the illustrated example, charging of an ignition capacitor Ci is performed at both ends of a primary coil W1 of the ignition coil. A diode D1 in a direction in which current flows is connected, and a resistor R1 is connected between the gate and cathode of the thyristor Th1. The control terminal 3b of the ignition circuit 3 is derived from the gate of the thyristor Th1.
[0036]
In the illustrated ignition circuit 3, the ignition capacitor Ci is charged to the illustrated polarity through the diode D1 and the primary coil W1 of the ignition coil by the output voltage of the DC-DC converter 3A. When an ignition signal Si is given from the electronic control unit 4 to be described later, the thyristor Th1 is turned on, so that the electric charge accumulated in the ignition capacitor Ci is discharged through the thyristor Th1 and the primary coil W1 of the ignition coil. This discharge causes a large change in the magnetic flux interlinking with the secondary coil W2 of the ignition coil, so that a high voltage for ignition is induced in the secondary coil W2. Since this high voltage is applied to the spark plug 7, a spark discharge is generated in the spark plug, and the internal combustion engine is ignited.
[0037]
As shown in FIG. 1, an ignition circuit in which an ignition capacitor is charged using a DC-DC converter is already known as disclosed in, for example, Japanese Patent No. 3119097.
[0038]
The electronic control unit 4 is a unit that controls ignition timing and the like, and includes a microcomputer having a CPU, a ROM, a RAM, a timer, and the like. A pulse signal generated by a signal generator 8 attached to the internal combustion engine is input to the electronic control unit through waveform shaping circuits 9A and 9B.
[0039]
The signal generator 8 includes a rotor 8a having a reluctator (inductor magnetic pole part) 8a1 so as to rotate together with the crankshaft of the engine, and a front end side and a rear end side in the rotation direction of the reluctator 8a1 of the rotor. A crank angle corresponding to the top dead center of the engine, which is a well-known one having a signal generator (pulsa) 8b that generates a first pulse Vs1 and a second pulse Vs2 having different polarities when edges are detected. A reference position set at a position sufficiently advanced from the position and an ignition position at the start of the engine set at a crank angle position slightly advanced from the crank angle position corresponding to the top dead center, respectively. A pulse signal Vs1 and a second pulse signal Vs2 are generated. The waveform shaping circuits 9A and 9B convert the first pulse Vs1 and the second pulse Vs2 generated by the signal generator 8b into waveform signals S1 and S2 that can be recognized by the CPU, and send them to the CPU of the electronic control unit 4. input.
[0040]
The electronic control unit constitutes an ignition timing control means for controlling the timing (ignition timing) for giving the ignition signal Si to the ignition circuit 3 by executing a predetermined program stored in the ROM, and the output of the power supply unit 1 Various means for monitoring the voltage and performing protection control for preventing the overvoltage from being applied to the ignition circuit 3 when the power supply unit 1 is abnormal are configured.
[0041]
The constant voltage power supply circuit 5 is a circuit that outputs a constant DC voltage (usually 5 V) Vcc necessary for driving the microcomputer constituting the electronic control unit 4 by using the output voltage of the power supply unit 1 as an input. The circuit 5 can ensure the voltage Vcc necessary for operating the electronic control unit 4 even when the battery 2 is removed and the power supply unit 1 outputs an overvoltage (the power supply unit 1 generates an overvoltage). Is configured to not break when).
[0042]
The voltage detection circuit 6 includes a voltage dividing circuit configured by a series circuit of resistors R2 and R3 connected between the output terminals of the power supply unit 1, and has a magnitude proportional to the output voltage of the power supply unit 1 at both ends of the resistor R3. The voltage detection signal Sv is output. This voltage detection signal Sv is input to an A / D input port 4 a provided in the electronic control unit 4. The electronic control unit 4 includes an ignition signal output terminal 4b, and an ignition signal Si output from the ignition signal output terminal is input to the control terminal 3b of the ignition circuit 3.
[0043]
The output voltage of the power supply unit 1 is monitored, and when it is detected that the output of the power supply unit 1 has become abnormal, the ignition control of the ignition circuit 3 is stopped, or protection control is performed to stop the ignition operation intermittently. FIG. 4 is a flowchart showing a routine algorithm that is executed by the microcomputer of the electronic control unit 4 at regular sampling intervals in order to be executed.
[0044]
The routine shown in FIG. 4 is executed at a predetermined sampling interval To (To = 5 msec in this example). In the case of this algorithm, first, in step 1, the digital value (referred to as A / D value) of the voltage detection signal Sv converted by the A / D converter is read. Next, in step 2, it is determined whether or not the overvoltage detection count n is 1 or more. n is a variable that is incremented by 1 each time it is detected that the A / D value exceeds the limit value, and its initial value is 0.
[0045]
Initially, since it is determined in step 2 that the number of detections n is not 1 or more, the process proceeds to step 4 to determine whether or not the measured value Tx of the timer exceeds the set detection time Ts. Since the timer is not activated at first and the measured value Tx of the timer is 0, the process proceeds to step 5 to determine whether or not the A / D value read this time exceeds the limit value. As a result, if the read A / D value does not exceed the limit value, the process returns to the main routine without doing anything thereafter.
[0046]
If it is determined in step 5 that the A / D value read this time exceeds the limit value, the process proceeds to step 6 where the overvoltage detection count n is incremented by 1, and then in step 7 n is set to the set count ns (this In the embodiment, it is determined whether or not ns = 5) or more. As a result, when it is determined that n is less than the set number of times, the process returns to the main routine without doing anything thereafter.
[0047]
When this routine is executed for the first time after setting n = 1 from the state of n = 0, since it is determined in step 2 that n is 1 or more, step 3 is executed and the set detection time is measured. The timer is started, and then step 4 and subsequent steps are performed. When n is 1 or more and the timer is started, it is determined in step 4 that the measured value Tx of the timer does not exceed the set detection time Ts. If it is determined in step 5 that the A / D value does not exceed the limit value, the process returns to the main routine. After the timer is started in this way, the routine returns to the main routine in a state where the A / D value does not exceed the limit value, and when this routine is executed next, it is determined in step 2 that n = 1. Therefore, step 3 for starting the timer is performed. At this time, since the timer is already started, the timer is not started, and the timer continues the time counting operation as it is.
[0048]
After the timer is started, if it is determined in step 5 that the A / D value exceeds the limit value in a state where the measured value Tx of the timer does not exceed the set detection time Ts, step 6 is executed. The overvoltage detection count n is incremented by one.
[0049]
In the process in which the routine of FIG. 4 is repeated, it is determined in step 4 that the measured value Tx of the timer does not exceed the set detection time Ts, and in step 7, it is determined that the overvoltage detection count n is equal to or greater than the set value ns. If the output of the power supply unit is abnormal, the routine proceeds to step 8, where the ignition operation of the ignition circuit is stopped and the engine is misfired to return to the main routine. This misfire process is, for example, a process for prohibiting the ignition timing control means described later from giving the ignition signal Si to the ignition circuit 3. By performing the misfire process, the rotational speed of the engine is reduced to reduce the output of the generator.
[0050]
Thereafter, when it is determined in step 4 that the measured value Tx of the timer has exceeded the set detection time Ts, step 9 is executed to set the overvoltage detection count n to 0, and the timer is reset. Step 9 is also executed when it is determined in step 7 that the measured value Tx of the timer has exceeded the set detection time Ts in step 4 in a state where the overvoltage detection count n is determined to be less than the set value ns. The timer is reset and the overvoltage detection count n is returned to zero.
[0051]
That is, in the present embodiment, it is detected that the power supply unit is abnormal when the overvoltage detection count reaches the set value ns after the overvoltage is detected once and before the timer measures the set detection time Ts. Thus, even if an overvoltage is detected by reducing the engine speed or stopping the engine, the number of detections n does not reach the set value within the set detection time Ts. In this case, the ignition circuit is caused to perform a normal ignition operation without detecting an abnormality in the power supply unit.
[0052]
The set value ns of the overvoltage detection count n is large enough to prevent the power supply unit from being judged to be abnormal when an overvoltage is detected due to noise or surge voltage intrusion, and start of over-voltage protection control Set to the value necessary to keep the delay of the product within the allowable range. In this embodiment, the set value ns for the number of overvoltage detections is set to 5.
[0053]
In addition, the set detection time Ts is longer than (sampling interval To) × (set value ns of overvoltage detection detection number), and in order to prevent erroneous detection of noise and surge voltage that appear once and that are in an overvoltage state. Set it not too long.
[0054]
In the case of the algorithm shown in FIG. 4, a power supply voltage sampling means for sampling the voltage between the output terminals of the power supply unit at a constant sampling interval is constituted by a timer (not shown) for measuring the sampling interval and step 1. .
[0055]
Further, by steps 2 and 3 in FIG. 4, it is determined whether or not the overvoltage detection count is equal to 1 each time the sampling means samples the power supply voltage, and the timer is started when the overvoltage detection count is equal to 1. Means are configured, and step 4 constitutes timer measurement value determination means for determining whether or not the time measured by the timer exceeds the set detection time.
[0056]
Further, in step 5 of FIG. 4, when the time measured by the timer determines that the time measured by the timer does not exceed the set detection time, the sample voltage for comparing the voltage sampled by the power supply voltage sampling means with the limit value. Overvoltage detection frequency counting means for incrementing the overvoltage detection frequency by 1 when the sampled voltage value comparison determination means determines that the sampled voltage value exceeds the limit value in step 6 Is configured.
[0057]
Further, in step 7 of FIG. 4, when the time measured by the timer determines that the time measured by the timer does not exceed the set detection time, when the overvoltage detection count reaches the set value, An overvoltage detection frequency determination means for determining that an abnormality has occurred is configured, and when the timer measurement value determination means determines that the time measured by the timer exceeds the set detection time in step 9, the timer is reset and A reset unit is configured to stop the time measuring operation and reset the overvoltage detection count to zero.
[0058]
The timer activation means, the timer measurement value determination means, the sample voltage value comparison determination means, the overvoltage detection frequency count means, the overvoltage detection frequency determination means, and the reset means constitute a power supply abnormality detection means. .
[0059]
Further, in step 8 of FIG. 4, when the power supply abnormality detecting means detects that an abnormality has occurred in the power supply unit, the power supply abnormality that controls the ignition circuit so as to reduce the rotational speed of the internal combustion engine or stop the internal combustion engine. Hour ignition control means is configured.
[0060]
The electronic control unit 4 also causes the CPU to execute a predetermined program so that the rotation speed of the engine is determined from the interval (the time required for the crankshaft to make one rotation) from the interval at which the signal generator 8 generates the first pulse signal Vs1. And a ignition timing control means for controlling the ignition timing during steady operation with respect to the detected rotation speed.
[0061]
The ignition timing control means ignites the engine ignition timing with respect to the rotational speed detected by the rotational speed detection means, for example, from the crank angle position (reference position) at which the signal generator 8 generates the first pulse signal Vs1. Ignition timing calculation means for calculating in the form of time (ignition timing measurement time) to be measured by the ignition timer until the engine rotates to the crank angle position corresponding to the timing, and when the calculated ignition timing is detected And ignition signal generating means for generating the ignition signal Si.
[0062]
The ignition signal generating means sets the ignition timing measurement time in the ignition timer when the first pulse signal Vs1 is generated and starts the measurement, and measures the ignition timing measurement time when the ignition timer is set. When completed, the ignition signal Si is generated.
[0063]
When the engine starts and at extremely low speeds below the idling speed, the crankshaft rotational speed varies greatly with changes in the engine stroke, and it is difficult to accurately detect the ignition timing with the ignition timer. The means generates the ignition signal Si when the signal generator detects that the second pulse signal Vs2 has been generated when the engine is started and at a very low speed.
[0064]
Since the algorithm of the program to be executed by the CPU for constituting the rotational speed detecting means, the ignition timing calculating means and the ignition signal generating means may be a known one, the algorithm of the program for realizing these means Detailed description is omitted.
[0065]
In the above embodiment, in a state where the battery 2 is connected between the output terminals of the power supply unit 1, as shown in FIG. 2A and FIG. A DC voltage Eo appears. As shown in FIG. 2A, when the output voltage Eo of the power supply unit is equal to or lower than the set value (limit value) Es, the power supply abnormality detection means does not detect the abnormality of the power supply unit. When detected, an ignition signal Si is output to cause the ignition circuit 3 to perform an ignition operation.
[0066]
As shown in FIG. 3A, when the battery is removed at time t1 during engine operation and the output voltage Eo of the power supply unit 1 exceeds the limit value Es, step 3 shown in FIG. 4 at time t2. Is started, and the number of times of overvoltage detection n reaches the set value at time t3 within the set detection time Ts. Therefore, at this time t3, the power supply abnormal part detecting means detects a power supply part abnormality. At this time, since the process of stopping the ignition operation of the ignition circuit is performed in step 8, the engine is in a misfire state, and the rotational speed thereof is reduced. Thereafter, when the set detection time Ts elapses at time t4, the set detection time measuring timer is reset. When the output speed of the generator is decreased due to a decrease in the rotation speed and the output voltage of the power supply unit becomes equal to or lower than the limit value Es as shown in FIG. 2A, the process for stopping the ignition operation is not performed. Is resumed.
[0067]
When the battery 2 is removed from between the output terminals of the power supply unit, as shown in FIGS. 2B and 3B, the output voltage Eo of the power supply unit 1 becomes a full-wave rectified waveform of the output voltage of the generator. A corresponding pulsation waveform is exhibited. In this example, it is assumed that no smoothing capacitor is provided on the output side of the rectifier circuit 1B. When the smoothing capacitor is provided, the output voltage waveform of the power supply unit when the battery is removed becomes a waveform in which a pulsation waveform is superimposed on a direct current component.
[0068]
Even when the battery is removed, as shown in FIG. 2 (B), when the peak value of the output voltage Eo of the power supply unit is less than or equal to the limit value Es, an overvoltage is not detected. In order not to detect the abnormality of the part 1, the electronic control unit 4 outputs an ignition signal Si when the ignition timing is detected, and causes the ignition circuit 3 to perform an ignition operation.
[0069]
When the peak value of the output voltage Eo of the power supply unit exceeds the limit value Es as shown in FIG. 3B with the battery removed, step 3 in FIG. 4 is performed when an overvoltage is detected at time t1. The set detection time measuring timer is started, and when the overvoltage detection count n reaches the set value ns (ns = 5 in this example) at time t2 within the set detection time Ts, the power supply abnormality detection unit detects the power supply unit. Detect anomalies. At this time, since the process of stopping the ignition operation of the ignition circuit is performed in step 8, the engine is in a misfire state, and the rotational speed thereof is reduced. Thereafter, when the set detection time Ts elapses at time t3, the set detection time measuring timer is reset. When the ignition operation is stopped, the rotational speed is reduced and the output of the generator is reduced. As shown in FIG. 2B, the ignition operation is stopped when the peak value of the output voltage of the power supply unit becomes equal to or lower than the limit value Es. The process is not performed and the ignition operation is resumed.
[0070]
As described above, if it is detected that the power supply unit is abnormal only when the overvoltage detection count reaches the set value during the set detection time Ts (when overvoltage is detected for the set count), noise is detected. If an overvoltage is detected by intrusion due to a surge or surge, the number of overvoltage detections will not reach the set value, so that when the noise or surge voltage is detected, an error is detected that the power supply is abnormal. Can be prevented.
[0071]
In addition, as described above, when it is determined that the power supply unit is abnormal only when an overvoltage is continuously detected a plurality of times, the voltage appearing between the output terminals of the power supply unit includes a pulsating waveform component. However, if the power supply unit is abnormal when the overvoltage detection count reaches the set value during the set detection time Ts as described above, the power supply unit cannot be accurately detected. If it is determined, even if a pulsation waveform component is included in the voltage appearing at the output terminal of the power supply unit, it can be accurately detected and a necessary protection operation can be performed.
[0072]
In the above embodiment, the set detection time Ts is measured by the set detection time measurement timer. However, the output voltage of the power supply unit is sampled at regular sampling intervals (5 msec in the above example). Therefore, it is possible to measure that the set detection time has elapsed by counting the number of times of sampling of the output voltage of the power supply unit.
[0073]
Further, in the above embodiment, when the abnormality of the power supply unit is detected, the ignition operation of the ignition circuit is stopped and the engine is misfired to reduce the engine speed. However, the abnormality of the power supply unit is detected. When this is done, the ignition circuit may be controlled so as to retard the ignition timing to reduce the engine speed.
[0074]
In some cases, the engine may be stopped while the ignition operation of the ignition circuit is stopped when an abnormality of the power supply unit is detected.
[0075]
In the above description, when an abnormality in the power supply unit is detected, the power supply abnormality point fire control means is configured to reduce the engine speed by causing the engine to misfire, but an abnormality in the power supply unit is detected. When a power failure occurs (when overvoltage is detected), regardless of the ignition timing calculated by the ignition timing control means, the engine ignition timing is retarded to reduce the engine speed. Control means may be configured.
[0076]
【The invention's effect】
As described above, according to the present invention, the abnormality of the power supply unit is detected when it is detected that the voltage exceeding the limit value is sampled more than the set number of times within the set detection time. Without over-sampling the sampling interval of the power supply, and without erroneously detecting that the power supply is abnormal when overvoltage is sampled due to noise, surge voltage, etc. Can be detected.
[0077]
Therefore, according to the present invention, when the battery is removed or the regulator function of the power supply unit is lost, and an abnormal voltage having a pulsating waveform appears in the output voltage of the power supply unit, it is necessary for controlling the ignition timing. From the sampling value of the output voltage of the power supply section obtained at a sampling interval that does not affect the correct calculation processing, it is possible to reliably detect that an abnormality has occurred in the power supply section and to control the ignition circuit etc. from overvoltage It can be done accurately.
[Brief description of the drawings]
FIG. 1 is a configuration diagram showing an overall configuration of an embodiment of the present invention.
2A is an output voltage of the power supply unit when the output voltage of the power supply unit is lower than the limit value in a state where a battery is connected to the power supply unit in the ignition device of FIG. 1. FIG. It is the wave form diagram which showed the waveform. (B) is a waveform showing the output voltage waveform of the power supply unit when the battery is removed from the power supply unit and the output voltage of the power supply unit is lower than the limit value in the ignition device of FIG. FIG.
3A is a waveform showing the output voltage waveform of the power supply unit when the output voltage of the power supply unit exceeds the limit value with the battery connected to the power supply unit in the ignition device of FIG. 1; FIG. (B) is a waveform diagram showing the output voltage waveform of the power supply unit when the output voltage of the power supply unit exceeds the limit value in the ignition device of FIG. 1 with the battery removed from the power supply unit.
4 is a flowchart showing an algorithm of a program executed by a CPU of an electronic control unit at a constant sampling interval in the ignition device shown in FIG.
FIG. 5 shows a malfunction in the case where an abnormality in the power supply unit is detected when the output voltage of the power supply unit exceeds the limit value continuously detected a plurality of times in the ignition device targeted by the present invention. It is a time chart for explaining.
FIG. 6 shows an ignition device as an object of the present invention, in which the sampling interval of the output of the power supply unit is made extremely fine so that the output voltage of the power supply unit exceeds the limit value is continuously detected a plurality of times. It is a time chart explaining the sampling operation | movement at the time of doing.
[Explanation of symbols]
1: power supply unit, 1A: AC generator, 1B: rectifier circuit with regulator function, 2: battery, 3: ignition circuit, 4: electronic control unit, 7: ignition plug.

Claims (5)

A power supply unit having at least an alternator driven by an internal combustion engine and a rectifier circuit for converting the output of the alternator into direct current, and when an ignition signal is given, the output voltage of the power supply unit is ignited as a power supply voltage In an internal combustion engine ignition device comprising: an ignition circuit for generating a high voltage for use; and an ignition timing control means for controlling a timing for applying the ignition signal to the ignition circuit.
Power supply voltage sampling means for sampling the output voltage of the power supply section at a constant sampling interval;
An overvoltage detection count that is the number of times that the voltage sampled by the power supply voltage sampling means exceeds a limit value is obtained, and an abnormality occurs in the power supply unit when the overvoltage detection count reaches a set value within a set detection time. Power supply abnormality detection means for detecting
When the power supply abnormality detecting means detects that an abnormality has occurred in the power supply unit, the power supply abnormality point fire control is performed to control the ignition circuit so as to reduce the rotational speed of the internal combustion engine or stop the internal combustion engine. Means,
An ignition device for an internal combustion engine comprising: The power supply abnormality detecting means is
Timer starting means for determining whether or not the number of times of overvoltage detection is 1 or more each time the sampling means samples a power supply voltage, and for starting a timer when the number of times of overvoltage detection is 1 or more;
Timer measurement value determination means for determining whether or not the time measured by the timer exceeds a set detection time;
Sample voltage value comparison and determination means for comparing the voltage sampled by the power supply voltage sampling means with a limit value when it is determined by the timer measurement value determination means that the time measured by the timer does not exceed a set detection time; ,
Overvoltage detection frequency counting means for incrementing the overvoltage detection frequency by 1 when the sampled voltage value comparison determination means determines that the sampled voltage value exceeds a limit value;
An abnormality occurs in the power supply unit when the overvoltage detection count reaches a set value in a state where the timer measured value determination means determines that the time measured by the timer does not exceed the set detection time. Overvoltage detection frequency determination means for determining whether or not
Reset means for resetting the timer to stop the time counting operation and reset the overvoltage detection count to 0 when the timer measurement value determination means determines that the time measured by the timer exceeds the set detection time When,
The ignition device for an internal combustion engine according to claim 1, comprising: 3. The internal combustion engine according to claim 1, wherein the power supply abnormality point fire control means is configured to stop the operation of the ignition circuit generating a high voltage for ignition while an abnormality of the power supply unit is detected. Engine ignition device. The power supply abnormality point fire control means is configured to intermittently stop the operation of the ignition circuit generating a high voltage for ignition while the abnormality of the power supply unit is detected. The ignition device for internal combustion engines as described. 3. The internal combustion engine ignition device according to claim 1, wherein the power supply abnormality point fire control means is configured to retard the ignition timing of the internal combustion engine while an abnormality of the power supply unit is detected.

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