JP2009057834A - Internal combustion engine control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an internal combustion engine control device which reliably prevents kickback by enhancing reverse rotation detection accuracy of an internal combustion engine. <P>SOLUTION: The internal combustion engine control device is equipped with a control means for executing a polarity determination process for determining a polarity of the alternating voltage signal at a prescribed frequency taking as input a single phase alternating voltage signal outputted from a magnetic alternating current generator which rotates synchronously with a crankshaft of an internal combustion engine and establishing a present polarity determination result when the same polarities are obtained for the prescribed number of times, and a reverse rotation detection process for grasping a polarity frequency of the alternating voltage signal by obtaining the present polarity determination result every detection of the crank signal and making the determination of the crank reverse rotation to stop the ignition control when the polarity frequency at the arrival of the ignition timing is inconsistent with the polarity frequency at the crank normal rotation. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

 The present invention relates to an internal combustion engine control device, and more particularly to an internal combustion engine control device having a reverse rotation detection function for an internal combustion engine.

  When the crankshaft rotation speed is insufficient at the start (cranking) of the internal combustion engine by manual operation, if ignition is performed before the compression top dead center, the crankshaft rotates in reverse, and the manual start operation device There is a case in which a reverse rotation load is applied to a (kick arm or the like), that is, so-called “ketchin” occurs.

Conventionally, as a technique for preventing such ketchin, (1) in an ignition device that performs an ignition output in accordance with an output voltage signal of a crank angle position detection timing sensor (crank sensor), an output voltage signal of a predetermined phase of the crank sensor The ignition output is stopped when a mismatch with the output voltage of a predetermined phase of one phase of the magnet type AC generator rotating in synchronization with the crankshaft is detected (see Patent Document 1 below), (2) Magnet In an igniter having a dedicated ignition power coil (so-called exciter coil) that is mounted in an AC generator and outputs a plurality of cycles of AC voltage per rotation in synchronization with the rotation of the crankshaft, the output voltage of the exciter coil in a predetermined phase (See Patent Document 2 below) and the like that stop the ignition output by the above.
Japanese Patent No. 2780257 Japanese Patent No. 3125587

  In the above prior art, when noise occurs in the output voltage signal of the magnet type AC generator (including the exciter coil) for detecting reverse rotation, the reverse rotation is erroneously detected only by detecting the predetermined phase of these signals once. If the internal combustion engine cannot be started or is in operation, engine stall may occur. In addition, when the magnet type AC generator or exciter coil is short-circuited with a power source such as another multi-phase generator or a battery, reverse rotation cannot be detected and ketchin cannot be prevented.

    The present invention has been made in view of the above-described circumstances, and an object thereof is to provide an internal combustion engine control device capable of improving the reverse rotation detection accuracy of an internal combustion engine and more reliably preventing kettin. To do.

   In order to achieve the above object, the present invention provides a crank signal output every time a crankshaft rotates by a predetermined angle from a crank angle detection means provided in an internal combustion engine as a first solution means for an internal combustion engine control device. Is an internal combustion engine control device that performs ignition control for igniting the internal combustion engine at the ignition timing, and outputs from a magnet type AC generator that rotates synchronously with the crankshaft of the internal combustion engine Polarity determination processing that receives the one-phase AC voltage signal to be input, determines the polarity of the AC voltage signal in a predetermined cycle, and sets the current polarity determination result when the polarity is the same polarity a predetermined number of times Each time the crank signal is detected, the current polarity determination result is obtained to grasp the polarity cycle of the AC voltage signal, and when the ignition timing has arrived, the polarity If the period of polarity period and inconsistencies during crankshaft forward rotation, a control means for performing the reverse rotation detection processing for stopping the ignition control determines that the crank reverse rotation, and wherein the.

    Further, as a second solving means relating to the internal combustion engine control apparatus, in the first solving means, the predetermined period is set to ¼ or less of a time between crank signals.

   Further, as a third solving means relating to the internal combustion engine control device, in the second solving means, a reference voltage source for generating a reference voltage signal, the AC voltage signal and the reference voltage signal are input, and the AC Comparing means for comparing the voltage values of the voltage signal and the reference voltage signal and outputting a comparison result signal indicating a comparison result; the crank signal as an input, and the crank signal required for the rotation of the predetermined angle Waveform shaping means for shaping and outputting a square wave pulse signal having a period as a period, and the control means determines the polarity of the AC voltage signal based on the comparison result signal in the polarity determination processing. In the reverse rotation detection process, the current polarity determination result is obtained every time the pulse signal is detected, and the polarity period of the AC voltage signal is grasped.

 According to the present invention, the polarity of the AC voltage signal output from the magnet type AC generator at a predetermined cycle is determined, and when the polarity is the same polarity a predetermined number of times, the current polarity determination result is obtained. Even when noise occurs in the AC voltage signal, the polarity of the AC voltage signal can be accurately determined. And, since reverse rotation is detected based on the polarity period of the AC voltage signal obtained from such an accurate polarity determination result, erroneous detection of reverse rotation is prevented, and the reverse rotation detection accuracy of the internal combustion engine is improved, It becomes possible to prevent kettin more reliably. Also, when an abnormality such as a short circuit occurs in the magnet type AC generator, the polarity cycle of the AC voltage signal is different from the cycle at the time of forward rotation. If the polarity cycle does not match, it is determined that the crank is reversely rotated and the ignition control is stopped, so that it is possible to prevent kettin even when an abnormality occurs.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic configuration diagram of an engine control system including an internal combustion engine control device (hereinafter referred to as ECU) in the present embodiment. As shown in FIG. 1, the engine control system in the present embodiment is roughly configured by an engine 1, a power supply unit 2, a fuel supply unit 3, and an ECU (Engine Control Unit) 4.

  The engine (internal combustion engine) 1 is a four-cycle single-cylinder engine, and includes a cylinder 10, a piston 11, a connecting rod 12, a crankshaft 13, an intake valve 14, an exhaust valve 15, an ignition plug 16, an ignition coil 17, an intake pipe 18, and an exhaust. A pipe 19, an air cleaner 20, a throttle valve 21, an injector 22, an intake pressure sensor 23, an intake air temperature sensor 24, a throttle opening sensor 25, a cooling water temperature sensor 26, and a crank angle sensor 27 are schematically configured.

  The cylinder 10 is a hollow cylindrical member for reciprocating the piston 11 provided therein by repeating four strokes of intake, compression, combustion (expansion), and exhaust, and is a mixture of air and fuel. Intake port 10a that is a flow path for supplying the combustion chamber 10b to the combustion chamber 10b, the air-fuel mixture is stopped, the combustion chamber 10b that is a space for burning the air-fuel mixture compressed in the compression stroke in the combustion stroke, and combustion in the exhaust stroke An exhaust port 10c, which is a flow path for exhausting exhaust gas from the chamber 10b to the outside, is provided. Further, a cooling water passage 10 d for circulating the cooling water is provided on the outer wall of the cylinder 10.

  A crankshaft 13 for converting the reciprocating motion of the piston 11 into a rotational motion is connected to the piston 11 via a connecting rod 12. The crankshaft 13 extends in a direction perpendicular to the reciprocating direction of the piston 11, and is connected to a flywheel, a transmission gear (not shown), and a rotor 30a in the power supply unit 2 described later.

  The intake valve 14 is a valve member for opening and closing an opening on the combustion chamber 10b side in the intake port 10a, and is connected to a camshaft (not shown) and is driven to open and close by the camshaft according to each stroke. . The exhaust valve 15 is a valve member for opening and closing the opening on the combustion chamber 10b side in the exhaust port 10c, and is connected to a camshaft (not shown), and is driven to open and close according to each stroke by the camshaft. .

  The spark plug 16 is provided at the uppermost part of the combustion chamber 10 b with the electrodes facing the combustion chamber 10 b, and generates a spark between the electrodes by a high-voltage ignition voltage signal supplied from the ignition coil 17. The ignition coil 17 is a transformer composed of a primary winding and a secondary winding, boosts an ignition voltage signal supplied from the ECU 4 to the primary winding, and supplies the boosted voltage signal to the ignition plug 16 from the secondary winding.

  The intake pipe 18 is a pipe for supplying air, and is connected to the cylinder 10 so that the internal intake flow path 18a communicates with the intake port 10a. The exhaust pipe 19 is a pipe for exhaust gas discharge, and is connected to the cylinder 10 so that the internal exhaust passage 19a communicates with the exhaust port 10c. The air cleaner 20 is provided on the upstream side of the intake pipe 18, cleans the air taken in from the outside, and sends it to the intake passage 18a. The throttle valve 21 is provided inside the intake passage 18a, and is rotated by a throttle (or an accelerator) (not shown). That is, as the throttle valve 21 rotates, the cross-sectional area of the intake passage 18a changes, and the intake air amount changes. The injector 22 is provided in the intake pipe 18 with the injection port directed toward the intake port 10a, and injects fuel supplied from the fuel supply unit 3 from the injection port in accordance with an injector drive signal supplied from the ECU 4. .

  The intake pressure sensor 23 is a semiconductor pressure sensor using, for example, a piezoresistive effect, and is provided in the intake pipe 18 with the sensitivity surface facing the intake flow path 18 a on the downstream side of the throttle valve 21. An intake pressure signal corresponding to the intake pressure is output to the ECU 4. The intake air temperature sensor 24 is provided in the intake pipe 18 with the sensing portion facing the intake flow path 18a on the upstream side of the throttle valve 21, and outputs an intake air temperature signal corresponding to the intake air temperature in the intake pipe 18 to the ECU 4. . The throttle opening sensor 25 outputs a throttle opening signal corresponding to the opening of the throttle valve 21 to the ECU 4. The cooling water temperature sensor 26 is provided with the sensitive part facing the cooling water passage 10d of the cylinder 10, and outputs a cooling water temperature signal corresponding to the temperature of the cooling water flowing through the cooling water passage 10d to the ECU 4. The crank angle sensor (crank angle detecting means) 27 outputs a crank signal every time the crankshaft 13 rotates by a predetermined angle in synchronization with the rotation of the crankshaft 13. Details of the crank angle sensor 27 will be described later.

  The power supply unit 2 includes a generator 30, a regulated rectifier 32, and a battery 33. The generator 30 is a magnet type AC generator, and is connected to the crankshaft 13 of the engine 1 to rotate synchronously, a permanent magnet 30b attached to the inner peripheral side of the rotor 30a, and a power generation output. For this purpose, three-phase stator coils 30c, 30d and 30e and a reverse rotation detection coil 30f are provided. That is, in the generator 30, the rotor 30a (that is, the permanent magnet 30b) rotates with respect to the fixed stator coils 30c, 30d, and 30e and the reverse rotation detection coil 30f, so that the stator coils 30c, 30d, and 30e A three-phase AC voltage signal is generated by electromagnetic induction, and a one-phase AC voltage signal is generated from the reverse rotation detection coil 30f. The three-phase AC voltage signal generated from the stator coils 30c, 30d, and 30e is output to the regulator rectifier 32, and the AC voltage signal generated from the reverse rotation detection coil 30f is output to the ECU 4.

As shown in FIG. 2, a plurality of protrusions are provided on the outer periphery of the rotor 30a so that the rear ends of the protrusions are equiangularly spaced (for example, 20 ° apart) with respect to the rotational direction. Further, the position in front of the position corresponding to the top dead center TDC in the rotation direction, for example, BTDC 10 °, that is, the position 10 ° before the top dead center is set as the crank angle reference position, and the rear end of the protrusion is located at the crank angle reference position. The protrusion to be provided is provided with a protrusion (crank angle reference protrusion 30a ₁ ) that is longer (for example, twice) in the rotation direction than the other protrusions. Hereinafter, it referred the projection other than the crank angle reference projection 30a ₁ and the auxiliary projections 30a _2.

 Moreover, the permanent magnet 30b is attached to the inner peripheral side of the rotor 30a so that one set of N poles and S poles is arranged every 60 °. The reverse rotation detection coil 30f is provided at the crank angle reference position, one end of which is connected to the ground line, and the other end is connected to the ECU 4 (more specifically, the inverting input terminal of the comparator circuit 53). In other words, the reverse rotation detection coil 30f generates an AC voltage signal that takes one period of time required for the rotor 30a (crankshaft 13) to rotate 60 °.

Crank angle sensor 27 described above, for example, an electromagnetic pickup sensor, as shown in FIG. 2, provided near the outer circumference of the rotor 30a, the crank angle reference projection 30a ₁ and the auxiliary projections 30a ₂ is near the crank angle sensor 27 A pair of pulse signals having different polarities are output to the ECU 4 every time they pass. More specifically, the crank angle sensor 27 outputs a pulse signal having a negative amplitude when the front end of each protrusion passes in the rotation direction, and the rear end of each protrusion in the rotation direction. When it passes, it outputs a pulse signal having a positive amplitude.

  Referring back to FIG. 1, the regulated rectifier 32 includes a rectifier circuit 32a and an output voltage adjustment circuit 32b. The rectifier circuit 32a is composed of six rectifier elements connected in a three-phase bridge for rectifying the three-phase AC voltage input from the stator coils 30c, 30d, and 30e. The voltage is rectified to a DC voltage and output to the output voltage adjustment circuit 32b. The output voltage adjustment circuit 32b adjusts the DC voltage input from the rectifier circuit 32a to generate a power supply voltage, and supplies the power supply voltage to the battery 33 and the ECU 4. The battery 33 is charged by the power supply voltage supplied from the output voltage adjustment circuit 32b, and supplies the power supply voltage to the ECU 4 when power is not supplied from the generator 30, such as during startup.

  The fuel supply unit 3 includes a fuel tank 40 and a fuel pump 41. The fuel tank 40 is a container for storing fuel such as gasoline. The fuel pump 41 is provided in the fuel tank 40 and pumps out the fuel in the fuel tank 40 and supplies it to the injector 22 in accordance with a pump drive signal input from the ECU 4.

As shown in FIG. 3, the ECU 4 includes a waveform shaping circuit 50, a rotation speed counter 51, a reference voltage source 52, a comparator circuit 53, an A / D converter 54, a CPU (Central Processing Unit) 55, an ignition circuit 56, and an injector drive. The circuit 57, the pump drive circuit 58, a ROM (Read Only Memory) 59, a RAM (Random Access Memory) 60, and a timer 61 are included. The ECU 4 having such a configuration is driven by the power supply voltage supplied from the power supply unit 2, the V _IG terminal of the ECU 4 is connected to the positive terminal of the battery 33, and the GND terminal is the negative terminal of the battery 33 and the ground. Connected to the line.

  The waveform shaping circuit (waveform shaping means) 50 converts the pulse-shaped crank signal input from the crank angle sensor 27 into a square-wave pulse signal (for example, a negative crank signal is a high level, a positive polarity and a ground level crank signal). The signal is set to a low level) and output to the rotation number counter 51 and the CPU 55. That is, the square-wave pulse signal is a square-wave pulse signal whose period is the time required for the crankshaft 13 to rotate 20 °. The rotational speed counter 51 calculates the engine rotational speed based on the square wave pulse signal output from the waveform shaping circuit 50 and outputs a rotational speed signal indicating the engine rotational speed to the CPU 55.

  The reference voltage source 52 generates a reference voltage signal that is a negative DC voltage, and outputs the reference voltage signal to the non-inverting input terminal of the comparator circuit 53. The comparator circuit (comparing means) 53 receives the AC voltage signal output from the reverse rotation detection coil 30f as an input to the inverting input terminal, and uses the reference voltage signal output from the reference voltage source 52 as an input to the non-inverting input terminal. It is composed of an operational amplifier, compares the voltage values of the AC voltage signal and the reference voltage signal, and outputs a comparison result signal indicating the comparison result to the CPU 55. Specifically, the comparator circuit 53 outputs a high-level comparison result signal when the voltage value of the AC voltage signal is larger than the voltage value of the reference voltage signal, and the voltage value of the AC voltage signal is the voltage value of the reference voltage signal. If smaller, a low level comparison result signal is output.

  The A / D converter 54 outputs the intake pressure sensor output from the intake pressure sensor 23, the intake air temperature sensor output from the intake air temperature sensor 24, the throttle opening sensor output from the throttle opening sensor 25, and the cooling. The coolant temperature sensor output output from the water temperature sensor 26 is converted into a digital signal and output to the CPU 55.

  The CPU (control means) 55 executes an engine control program stored in the ROM 59, and outputs a crank signal, a rotation speed signal input from the rotation speed counter 51, a comparison result signal input from the comparator circuit 53, and an A / D. Based on the intake pressure value, the throttle opening value, and the cooling water temperature value converted by the converter 52, control relating to fuel injection, ignition, and fuel supply of the engine 1 is performed. Specifically, the CPU 55 outputs an ignition control signal for sparking the spark plug 16 at the ignition timing to the ignition circuit 56, and a fuel injection control signal for injecting a predetermined amount of fuel from the injector 22 at the fuel injection timing. Is output to the injector drive circuit 57, and a fuel supply control signal for supplying fuel to the injector 22 is output to the pump drive circuit 58.

The ignition circuit 56 includes a capacitor (not shown) that stores the V _IG voltage, that is, the power supply voltage supplied from the power supply unit 2, and is stored in the capacitor in accordance with the ignition control signal input from the CPU 55. The electric charge is discharged to the primary winding of the ignition coil 17 as an ignition voltage signal. The injector drive circuit 57 generates an injector drive signal for injecting a predetermined amount of fuel from the injector 22 according to the fuel injection control signal input from the CPU 55, and outputs the injector drive signal to the injector 22. The pump drive circuit 58 generates a pump drive signal for supplying fuel from the fuel pump 41 to the injector 22 in accordance with the fuel supply control signal input from the CPU 55, and outputs the pump drive signal to the fuel pump 41. To do.

  The ROM 59 is a non-volatile memory that stores in advance an engine control program executed by the CPU 55 and various data. The RAM 60 is a working memory used as a temporary storage destination of data when the CPU 55 executes an engine control program and performs various operations. The timer 61 performs a predetermined timer (time keeping) operation under the control of the CPU 55.

  Next, in the engine control system including the ECU 4 (internal combustion engine control device) of the present embodiment configured as described above, the reverse rotation prevention process of the ECU 4 (particularly the CPU 55) during the operation of the engine 1 will be described. The CPU 55 performs the reverse rotation prevention process based on the coil voltage polarity determination process for determining the polarity of the AC voltage signal output from the reverse rotation detection coil 30f and the polarity determination result obtained by the coil voltage polarity determination process. The reverse rotation detection process for detecting the reverse rotation of the engine 1 is executed in parallel. First, the coil voltage polarity determination process will be described below.

<Coil voltage polarity determination processing>
FIG. 4 shows a crank signal output from the crank angle sensor 27, a crank signal after waveform shaping output from the waveform shaping circuit 50, an AC voltage signal output from the reverse rotation detection coil 30f, and a reference voltage source 52. 5 is a timing chart showing a correspondence relationship between a reference voltage signal output from a comparator, a comparison result signal output from a comparator circuit 53, and a polarity determination result (current voltage polarity determination result) of an AC voltage signal.

 As shown in FIG. 4, during operation of the engine 1, the rotor 30 a also rotates in synchronization with the rotation of the crankshaft 13, and when the crank angle sensor 27 passes the front end of each protrusion with respect to the rotation direction, A pulsed crank signal having a negative amplitude is output, and when the rear end of each protrusion passes, a pulsed crank signal having a positive amplitude is output. The waveform shaping circuit 50 outputs a crank signal (square wave pulse signal) that has been shaped so that the negative polarity crank signal is at a high level and the positive polarity and ground level crank signals are at a low level.

 That is, the time between the falling edges of the crank signal after waveform shaping corresponds to the time required for the crankshaft 13 to rotate 20 °. Further, the reverse rotation detection coil 30f outputs an AC voltage signal that takes one period of time required for the rotor 30a (crankshaft 13) to rotate 60 °, and the comparator circuit 53 outputs the voltage of the AC voltage signal. When the value is larger than the voltage value of the reference voltage signal (that is, when the AC voltage signal is positive), a high-level comparison result signal is output, and the voltage value of the AC voltage signal is smaller than the voltage value of the reference voltage signal ( That is, a low-level comparison result signal is output when the AC voltage signal is negative.

  During the operation of the engine 1, the CPU 55 performs a coil voltage polarity determination process based on the comparison result signal as described above. FIG. 5 is an operation flowchart of the CPU 55 regarding the coil voltage polarity determination processing. As shown in FIG. 5, first, the CPU 55 controls the timer 61 to determine whether or not the comparator output detection period (predetermined period) has arrived (step S1). This comparator output detection cycle is preferably set to ¼ or less of the time between crank signals (time between falling edges of the crank signal after waveform shaping). In this embodiment, as shown in FIG. (Μsec). Thus, by setting the comparator output detection cycle to a short cycle, as described below, even when pulsed noise is generated in the AC voltage signal output from the reverse rotation detection coil 30f, The polarity of the AC voltage signal can be accurately determined.

  In step S1, the CPU 55 repeats the process of step S1 when the comparator output detection cycle has not arrived (“No”), and takes in the comparison result signal when the comparator output detection cycle has arrived (“Yes”). The polarity of the current AC voltage signal (hereinafter referred to as the current coil voltage polarity) is determined (step S2). That is, the CPU 55 determines that the current coil voltage polarity is positive when the comparison result signal is high, and determines negative when the comparison result signal is low.

  Then, the CPU 55 determines whether or not the current coil voltage polarity matches the current AC voltage signal polarity determination result (current voltage polarity determination result) stored in the RAM 60 (step S3). In step S3, when the current coil voltage polarity matches the current voltage polarity determination result (“Yes”), the CPU 55 returns to the process of step S1. On the other hand, in step S3, when the current coil voltage polarity does not match the current voltage polarity determination result (“No”), the CPU 55 stably stabilizes the current coil voltage polarity to the same polarity for a predetermined number of times (for example, 3 times). It is determined whether or not (step S4).

  In this step S4, when the current coil voltage polarity is not stable to the same polarity a predetermined number of times (“No”), the CPU 55 returns to the process of step S1. On the other hand, if the current coil voltage polarity is stable at the same polarity for a predetermined number of times (“Yes”) in step S4, the CPU 55 reflects the current coil voltage polarity in the current voltage polarity determination result (new in the RAM 60). The current voltage polarity determination result is stored), and the process returns to step S1 (step S5).

The processing of steps S3 to S5 will be specifically described with reference to FIG. As shown in FIG. 4, when the current voltage polarity determination result is low level (that is, negative polarity) before time t0 and the comparison result signal is high level at time t0, that is, when the current coil voltage polarity is positive. As a result, in step S3, since the current coil voltage polarity does not match the current voltage polarity determination result, the CPU 55 proceeds to step S4, where the current coil voltage polarity is the same for a predetermined number of times (three times). It is determined whether or not the polarity is positive (positive polarity in FIG. 4). Here, as shown in FIG. 4, the CPU 55 counts the number of times that the current coil voltage polarity is positive for each comparator output detection period, and the current coil voltage polarity is 3 times and positive (time). At t1), the process proceeds to step S5, where the current coil voltage polarity is reflected in the current voltage polarity determination result and stored in the RAM 60 as a new current voltage polarity determination result. That is, the current voltage polarity determination result is low level (that is, negative polarity) before time t1, but the current voltage polarity determination result is high level (that is, positive polarity) after time t1.
Since the comparison result signal remains at the high level during the period from time t1 to time t2, the current coil polarity polarity coincides with the current voltage polarity determination result, and the current voltage polarity determination result is at the high level (that is, positive polarity). Will be maintained.

 Here, as shown in FIG. 4, a case where pulsed noise is generated in the AC voltage signal and the comparison result signal transitions to the low level (that is, the current coil voltage polarity is negative) only during the period of time t2 to t3. Suppose. At this time t2, since the current coil voltage polarity does not match the current voltage polarity determination result, the CPU 55 proceeds to the process of step S4 and determines the number of times that the current coil voltage polarity is negative for each comparator output detection period. However, since the comparison result signal transitions to a high level at time t3, the number of times that the coil voltage polarity is negative this time does not reach three, and the current voltage polarity determination result is high level (that is, positive polarity). ) Will be maintained.

 Subsequently, assuming that the comparison result signal transitions to a low level (that is, the current coil voltage polarity is negative) at time t4, the CPU 55 determines the current coil voltage polarity and the current voltage polarity determination result in the process of step S3. Therefore, the process proceeds to step S4, and it is determined whether or not the current coil voltage polarity is stable a predetermined number of times (three times) and the same polarity (negative polarity in FIG. 4). Here, as shown in FIG. 4, the CPU 55 counts the number of times that the current coil voltage polarity is negative for each comparator output detection period, and when the current coil voltage polarity is negative three times (time) At t5), the process proceeds to step S5, where the current coil voltage polarity is reflected in the current voltage polarity determination result and stored in the RAM 60 as a new current voltage polarity determination result. That is, the current voltage polarity determination result is high level (that is, positive polarity) before time t5, but the current voltage polarity determination result is low level (that is, negative polarity) after time t5.

  As described above, the polarity of the AC voltage signal output from the reverse rotation detection coil 30f is detected in a short period (less than ¼ of the time between crank signals), and is stable to the same polarity a predetermined number of times. In this case, by determining the current polarity, the polarity of the AC voltage signal can be accurately determined even when pulsed noise is generated in the AC voltage signal.

<Reverse rotation detection process>
Next, the reverse rotation detection process performed in parallel with the coil voltage polarity determination process described above will be described. FIG. 6 is an operation flowchart of the CPU 55 regarding the reverse rotation detection process. As shown in FIG. 6, first, the CPU 55 determines whether a crank signal after waveform shaping is input (a falling edge is detected) or not (step S10), and the crank signal after waveform shaping is input. If it is detected ("Yes"), it is determined whether or not reverse rotation has been detected (step S11). In step S11, when the reverse rotation has been detected (“Yes”), the CPU 55 proceeds to the process of step S19.

On the other hand, if the reverse rotation has not been detected in step S11 (“No”), the CPU 55 reads the current voltage polarity determination result from the RAM 60 (step S12), and the polarity cycle of the AC voltage signal based on the current voltage polarity determination result. (Hereinafter referred to as the coil voltage polarity cycle) is updated (step S13). Then, the CPU 55 determines whether or not the ignition timing has arrived (whether the crank angle reference position has been detected) based on the crank signal after waveform shaping (step S14). As shown in FIG. 7, the crank angle reference position, because the crank angle reference projection 30a ₁ large width passes the crank angle sensor 27, since the long pulse signal having a high level period is generated, such a high-level period When the falling edge of the long pulse signal is detected, it can be determined that the crank angle reference position has been detected (ignition timing has arrived). In addition to the coil voltage polarity determination process and the reverse rotation detection process, the CPU 55 performs the crank angle reference position BTDC detection process in parallel based on the crank signal after waveform shaping as described above.

  If the ignition timing has not arrived (the crank angle reference position has not been detected) in step S14 (“No”), the CPU 55 returns to the process of step S10. On the other hand, when it is determined in step S14 that the ignition timing has arrived (the crank angle reference position has been detected) (“Yes”), the CPU 55 determines whether or not the coil voltage polarity cycle matches the cycle during forward rotation. Is determined (step S15).

  FIG. 7 is a timing chart of each signal during forward rotation, and FIG. 8 is a timing chart of each signal when reverse rotation occurs. As shown in FIG. 7, during positive rotation, every time the crank signal after waveform shaping is input three times, that is, every time the crankshaft 13 (rotor 30a) rotates 60 °, “positive polarity” → “positive polarity” "→" Negative polarity "is the coil voltage polarity cycle. On the other hand, as shown in FIG. 8, when reverse rotation occurs, the coil voltage polarity cycle changes. In the example of FIG. 8, “positive polarity” → “positive polarity” → “negative polarity” is set as one cycle before the occurrence of reverse rotation. Positive polarity ". FIG. 9 is a timing chart of each signal when an abnormality occurs such as when the reverse rotation detection coil 30f is short-circuited to the stator coils 30c, 30d, 30e, the battery 33, or the like during forward rotation. As shown in the figure, it can be seen that the coil voltage polarity cycle at the time of occurrence of abnormality is also different from the cycle at the time of forward rotation.

  That is, in step S15, as shown in FIG. 7, when the coil voltage polarity cycle matches the cycle at the time of forward rotation (“Yes”), the CPU 55 determines that the engine 1 is in the forward rotation state (step S16). ), An ignition output permission, that is, an ignition control signal for sparking the spark plug 16 is output to the ignition circuit 56, and the process returns to step S10 (step S17). On the other hand, in step S15, as shown in FIG. 8 or FIG. 9, when the coil voltage polarity cycle does not coincide with the cycle during forward rotation (“No”), the CPU 55 determines that the engine 1 is in the reverse rotation state. (Step S18), the ignition output prohibition, that is, the output of the ignition control signal to the ignition circuit 56 is stopped, and the process returns to Step S10 (Step S19).

  In step S10, when the crank signal after waveform shaping is not input (“No”), the CPU 55 controls the timer 61 to check whether the crank signal after waveform shaping has been input within a predetermined time (whether it is an engine stall). It is determined whether or not (step S20). In step S20, the CPU 55 returns to the process of step S10 when there is an input of a crank signal after waveform shaping within a predetermined time, that is, when it is not an engine stall ("No"), while the waveform is within the predetermined time. When there is no input of the crank signal after shaping, that is, when it is determined that the engine is stalled (“Yes”), the reverse rotation detection state is reset and the process returns to step S10 (step S21).

  As described above, according to the present embodiment, even when noise occurs in the AC voltage signal that is the output signal of the reverse rotation detection coil 30f, the polarity of the AC voltage signal can be accurately determined. As a result, it is possible to prevent erroneous detection of reverse rotation, improve the reverse rotation detection accuracy of the engine 1, and prevent kettin more reliably. Also, when an abnormality occurs such as when the reverse rotation detection coil 30f is short-circuited with the stator coils 30c, 30d, 30e, the battery 33, etc., the ignition control signal is output to the ignition circuit 56 in the same manner as when the reverse rotation is detected. It is possible to prevent kettin by stopping the process.

  In the above-described embodiment, the reverse rotation detection coil 30f dedicated to reverse rotation detection is provided in the generator 30. However, the present invention is not limited to this, and the generator 30 rotates in synchronization with the crankshaft 13 in addition to the generator 30, and is one-phase. A magnet-type AC generator that outputs an AC voltage signal may be provided, and an exciter coil may be used as the reverse rotation detection coil 30f.

1 is a schematic configuration diagram of an engine system including an internal combustion engine control device (ECU 4) according to an embodiment of the present invention. It is detailed explanatory drawing of the rotor 30a which comprises the generator 30 which concerns on one Embodiment of this invention. 1 is a configuration block diagram of an internal combustion engine control device (ECU 4) according to an embodiment of the present invention. It is a 1st explanatory view about operation of an internal-combustion-engine control device (ECU4) concerning one embodiment of the present invention. It is the 2nd explanatory view about operation of an internal-combustion-engine control device (ECU4) concerning one embodiment of the present invention. It is a 3rd explanatory view about operation of an internal-combustion-engine control device (ECU4) concerning one embodiment of the present invention. It is a 4th explanatory view about operation of an internal-combustion-engine control device (ECU4) concerning one embodiment of the present invention. It is a 5th explanatory view about operation of an internal-combustion-engine control device (ECU4) concerning one embodiment of the present invention. It is a 6th explanatory view about operation of an internal-combustion-engine control device (ECU4) concerning one embodiment of the present invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Engine, 2 ... Power supply part, 3 ... Fuel supply part, 4 ... ECU (Engine Control Unit), 10 ... Cylinder, 11 ... Piston, 12 ... Connecting rod, 13 ... Crankshaft, 14 ... Intake valve, 15 ... Exhaust Valve, 16 ... Spark plug, 17 ... Ignition coil, 18 ... Intake pipe, 19 ... Exhaust pipe, 20 ... Air cleaner, 21 ... Throttle valve, 22 ... Injector, 23 ... Intake pressure sensor, 24 ... Intake temperature sensor, 25 ... Throttle Opening sensor, 26 ... cooling water temperature sensor, 27 ... crank angle sensor, 30 ... generator, 32 ... regulator rectifier, 33 ... battery, 40 ... fuel tank, 41 ... fuel pump, 50 ... waveform shaping circuit, 51 ... Rotational speed counter 52 52 Reference voltage source 53 53 Comparator circuit 54 A / D converter 55 CPU (Central Processing Unit) 6 ... ignition circuit, 57 ... injector drive circuit, 58 ... pump drive circuit, 59 ... ROM (Read Only Memory), 60 ... RAM (Random Access Memory), 61 ... timer

Claims (3)

Based on a crank signal output every time the crankshaft rotates by a predetermined angle from a crank angle detection means provided in the internal combustion engine, the ignition timing is grasped, and ignition control for igniting the internal combustion engine at the ignition timing is performed. An internal combustion engine control device,
The input is a one-phase AC voltage signal output from a magnet type AC generator that rotates synchronously with the crankshaft of the internal combustion engine,
A polarity determination process that determines the polarity of the AC voltage signal at a predetermined cycle and sets the current polarity determination result when the polarity is the same polarity a predetermined number of times,
Each time the crank signal is detected, the current polarity determination result is obtained to determine the polarity cycle of the AC voltage signal. When the ignition timing has arrived, the polarity cycle does not match the polarity cycle at the time of forward crank rotation. In this case, a reverse rotation detection process for determining the reverse rotation of the crank and stopping the ignition control is provided.
An internal combustion engine control device.  2. The internal combustion engine controller according to claim 1, wherein the predetermined period is set to ¼ or less of a time between crank signals. A reference voltage source for generating a reference voltage signal;
Comparison means for inputting the AC voltage signal and the reference voltage signal, comparing the voltage values of the AC voltage signal and the reference voltage signal, and outputting a comparison result signal indicating a comparison result;
Waveform shaping means that takes the crank signal as input, shapes the crank signal into a square-wave pulse signal having a period of time required for rotation of the predetermined angle, and outputs the waveform signal;
With
The control means determines the polarity of the AC voltage signal based on the comparison result signal in the polarity determination process, and acquires the current polarity determination result every time the pulse signal is detected in the reverse rotation detection process. And grasping the polarity period of the AC voltage signal,
The internal combustion engine control apparatus according to claim 1 or 2, characterized in that

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