JP2005240759A - Ignition device for internal-combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ignition device for an internal-combustion engine to sense the ignition position computed in combined use of counting the crank angle signals and measuring the measuring values with an ignition timer, in which the ignition position is sensed accurately without being influenced by the phase difference between the reference signal and the crank angle signal. <P>SOLUTION: The ignition device for the internal-combustion engine is structured so that the phase difference between the reference signal Vs1 and crank angle signal Vcr is determined as an error angle Δβ, and the target count value So is determined by dividing the angle obtained by subtracting the error angle Δβ from the angle λ1 for the distance from the reference position θ1 as the position where the reference signal Vs1 is generated to the target ignition position θi1 by the unit angle θu as the interval at which the reference angle signals are generated, while the counting by the ignition timer is started when the count value Sk of the crank angle signals Vcr has attained the target count value, and the crank angle position where the counting by the ignition timer is completed is sensed as the target ignition position θi1, and in this ignition position an ignition signal is given to the ignition circuit so as to conduct the ignition operation. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an internal combustion engine ignition device suitable for igniting an internal combustion engine used in an outboard motor or the like.

  An internal combustion engine ignition device includes an ignition circuit that generates a high voltage for ignition when an ignition signal is applied, and an ignition position control device that controls a position at which the ignition signal is applied to the ignition circuit using a microcomputer. Is done.

  When the ignition position of the internal combustion engine (crank angle position for performing the ignition operation) is controlled using a microcomputer, a specific crank angle position of the engine is determined as a reference position, and this reference position is detected. Measurement of the calculated ignition position is started, and when the measurement is completed (when the ignition position is detected), an ignition signal is given to the ignition circuit to perform an ignition operation.

  In an ignition device that performs this type of control, a signal generator that detects the edge of a reluctator provided on a rotor attached to a crankshaft of an engine and generates a pulse signal is provided, and this signal generator is provided for the engine. A pulse signal generated at a specific crank angle position is used as a reference signal, and the generation position of the reference signal is set as a reference position. The microcomputer calculates the target ignition position with respect to control conditions such as the engine speed, and causes the ignition timer to measure the calculated target ignition position while the crankshaft rotates from the reference position to the target ignition position. Convert to (ignition timer measurement time).

  When the signal generator generates the reference signal, the ignition timer measurement time is set in the ignition timer to start the measurement, and the crank angle position when the ignition timer completes the measurement of the ignition timer measurement time is ignited. As a position, an ignition signal is given to the ignition circuit at this ignition position.

  The ignition timer measurement time used for measuring the target ignition position is determined by the angle from the reference position to the target ignition position and the rotational speed of the crankshaft (the rotational speed of the crankshaft). Therefore, in order to accurately detect the target ignition position calculated for various control conditions and perform the ignition operation at the calculated target ignition position, it is necessary to calculate the ignition timer measurement time. It is necessary that the rotational speed of the engine matches the rotational speed of the engine when measuring the target ignition position.

  When the internal combustion engine is operated at a certain rotational speed, the rotational speed when calculating the ignition timer measurement time (the rotational speed detected immediately before) and the rotational speed when measuring the target ignition position Therefore, the ignition position can be controlled without any trouble by detecting the ignition position by the above method.

  However, when starting the engine and rotating at an extremely low speed, the rotation speed of the crankshaft fluctuates finely with changes in the stroke of the engine, so when measuring the rotation speed and the target ignition position when calculating the ignition timer measurement time A large difference occurs between the rotational speed and the target ignition position cannot be accurately detected by the above method.

  Therefore, at the time of starting the engine and at the time of extremely low speed, ignition is not performed at the calculated ignition position, but a fixed ignition pulse is generated from the signal generator at a crank angle position suitable as an ignition position at the time of extremely low speed of the engine. A signal is generated, and when a fixed ignition pulse signal is generated, an ignition signal is given to the ignition circuit to perform an ignition operation. In this case, the ignition position at an extremely low speed of the engine is fixed at the position where the fixed ignition pulse signal is generated, and the ignition position is not controlled with respect to the control conditions such as the rotational speed.

  However, depending on the application of the internal combustion engine, it may be necessary to control the ignition position with respect to various control conditions even during extremely low speed operation. For example, an internal combustion engine used for an outboard motor or the like is operated in an extremely low speed state when performing trolling, so that it is necessary to stably operate in an extremely low speed state, and even during an extremely low speed operation. It is necessary to control the ignition position.

  Therefore, a crank angle sensor that detects the teeth of the ring gear attached to the outer periphery of the flywheel to mesh with the pinion gear attached to the starter motor in order to stably control the ignition position during extremely low speed operation. Locating in the vicinity of the ring gear and detecting the ignition position by counting the signal generated each time the crank angle sensor detects each tooth of the ring gear (every time the crankshaft rotates by a certain angle) Has been done. The crank angle sensor is configured in the same manner as the signal generator, and generates pulses having different polarities when the edges at both ends of each tooth of the ring gear are detected.

  In this method, a pair of pulses generated when the crank angle sensor detects the edges of both ends of each tooth of the ring gear are input to a waveform shaping circuit such as a flip-flop circuit, thereby obtaining the width of the ring gear teeth. The signal is converted into a rectangular wave-shaped crank angle signal having a corresponding signal width, and the signal generator causes the counter to start counting the crank angle signal with the crank angle position where the reference signal is generated as the counting start position. Then, the crank angle position when the count value of the counter reaches the target value is set as the ignition position of the engine, and the ignition operation is performed by giving an ignition signal to the ignition circuit at the ignition position.

  5A shows the pulse signal Vs1 generated at the reference position by the signal generator with respect to the crank angle θ, and FIG. 5B shows that the pulse generated by the crank angle sensor is input to the waveform shaping circuit. The waveform of the crank angle signal Vcr generated by the above is shown. The rising edge and falling edge of each crank angle signal Vcr correspond to the front end side edge and the rear end side edge in the rotation direction of each tooth of the ring gear, respectively. The crank angle signal Vcr is generated every time the crankshaft rotates by a unit angle θu corresponding to the tooth pitch of the ring gear.

  FIG. 5C shows a method of detecting the ignition position by counting the crank angle signal Vcr in the conventional ignition device. In the conventional ignition device, the crank angle signal (reference position) θ1 at which the reference signal Vs1 generated by the signal generator reaches the threshold value Vt is taken as the count start position, and the crank angle signal generated after the count start position is counted by the counter. Count. The stepped waveform in FIG. 5C shows a change in the count value Sk of the counter, and the count value of the counter is incremented by 1 each time a new crank angle signal Vcr rises. The crank angle position when the count value Sk of the crank angle signal by the counter reaches the target value So is set as an ignition position θi1 ′, and an ignition signal is given to the ignition circuit at this ignition position to perform an ignition operation. The target value So is obtained by dividing the angle λ1 from the reference position θ1 to the target ignition position θi1 by the unit angle θu corresponding to one pitch of the teeth of the ring gear and rounding off the decimal part.

  When the angle λ1 from the reference position θ1 to the target ignition position θi1 is divided by the unit angle θu, since it is generally not divisible, the target value So of the count value of the crank angle signal is obtained as described above, and the count value Sk is obtained. When the crank angle position when the target value So is reached is set as the ignition position, an angle (corresponding to one pitch of the teeth of the ring gear at the maximum between the actual ignition position θi1 ′ and the target ignition position θi1 ( An error Δα corresponding to (unit angle) θu occurs.

  Also, the phase difference Δβ that can occur between the reference signal Vs1 and the crank angle signal Vcr due to an error in the mounting position of the crank angle sensor and the signal generator is a maximum of one ring gear tooth pitch (unit angle θu). Therefore, the error Δα + Δβ that can occur between the actual ignition position and the target ignition position reaches a maximum of two pitches (2θu) of the teeth of the ring gear.

  In addition, when the ignition position is obtained by counting the crank angle signal, the resolution of the ignition position control is determined by the number of teeth of the ring gear even if the mounting accuracy of the signal generator and the crank angle sensor is sufficiently increased. Therefore, the ignition position cannot be finely controlled. Therefore, when the ignition position is detected by the above method even at high engine speeds where it is necessary to finely control the ignition position under various control conditions, the ignition position is accurately controlled. I can't make it happen.

  Therefore, in the ignition device disclosed in Patent Document 1, in the extremely low speed rotation region where the fluctuation of the rotation speed is severe, the crank angle signal Vcr is counted with the reference position θ1 as the measurement start position as shown in FIG. Thus, a normal method of detecting the ignition position θin (n is the number of the cylinder to be ignited, n = 1 in FIG. 5) and causing the ignition timer to measure the ignition timer measurement time in the rotation region where the engine rotation speed is stable. Thus, the ignition position is detected.

  However, even in the ignition device disclosed in Patent Document 1, in the rotational speed region where the ignition position is obtained by counting the crank angle signal Vcr, as described above, depending on the accuracy of the mounting position of the signal generator and the crank angle sensor. An error between the actual ignition position and the target ignition position becomes large, and the ignition position may not be accurately controlled. In order to solve such a problem, as disclosed in Patent Document 2, an ignition device has been proposed in which the counting of the crank angle signal and the timing operation by the ignition timer are used in combination.

In the ignition device disclosed in Patent Document 2, as shown in FIG. 5D, the reference position θ1 where the signal generator generates the reference signal Vs1 is set as the measurement start position of the crank angle signal. After the counting of the crank angle signal Vcr is started, the crank angle position θ2 when the count value Sk reaches the target value So is set as the ignition position measurement start position, and the ignition timer is measured at the ignition start time at the measurement start position θ2. Is started to measure the ignition position obtained by calculation. St in FIG. 5D indicates the measured value of the ignition timer. The crank angle position when the measured value of the ignition timer reaches the target value (ignition timer measured time) ti1 is defined as the ignition position θi1 ′. An ignition signal is given to the ignition circuit at the ignition position to perform an ignition operation.
JP-A-10-141193 Japanese Patent No. 2653212

  As shown in Patent Document 2, even when the counting of the crank angle signal and the measurement of the ignition timer measurement time by the ignition timer are used in combination, the phase difference Δβ that can occur between the reference signal Vs1 and the crank angle signal Vcr is used. (Refer to FIG. 5D) Δγ (refer to FIG. 5D) may occur between the actual ignition position θi1 ′ and the target ignition position θi1. It was difficult to control accurately.

  An object of the present invention is for an internal combustion engine in which a phase difference between a reference signal and a crank angle signal is prevented from appearing as an ignition position detection error, and the ignition position of the engine can be accurately controlled. It is to provide an ignition device.

  The present invention relates to a signal generator that generates a reference signal at a specific crank angle position of an internal combustion engine, a crank angle sensor that generates a crank angle signal each time the crankshaft of the internal combustion engine rotates by a unit angle θu, The ignition position calculating means for calculating the ignition position, the crank angle signal counting means for counting the crank angle signal with the crank angle position where the reference signal is generated as the counting start position, and the crankshaft is calculated from the reference position by the ignition position calculating means. Target count value determining means for determining the number of crank angle signals to be counted by the crank angle signal generating means while rotating to the ignition position as a target count value, and the count value counted by the crank angle signal counting means as the target count value. The remaining crank angle is calculated as the ignition angle measurement start position, and the angle from the ignition position measurement start position to the ignition position is calculated as the remaining angle θx. An angle calculation means, an ignition timer measurement time calculation means for obtaining a time required for the crankshaft to rotate the remaining angle θxn as an ignition timer measurement time tin, and an ignition timer measurement time tin at the ignition position measurement start position. Ignition signal generating means for generating an ignition signal when the ignition timer completes the measurement of the ignition timer measurement time, and for ignition applied to an ignition plug attached to the cylinder of the internal combustion engine when the ignition signal is generated An ignition device for an internal combustion engine provided with an ignition circuit that generates a high voltage is intended.

  In the present invention, in order to achieve the above-mentioned object, the target count value determining means is adapted to detect the crank angle position when the reference signal is generated and the first crank angle signal first counted by the crank angle signal counting means. An error angle detection means for detecting an angle between the generated position as an error angle Δβ and an angle λn (n is 1 or more and the number of cylinders) from the reference position to the ignition position θin of each cylinder calculated by the ignition position calculation means The maximum target count value that is calculated as the maximum target count value CNnmax, which is obtained by dividing the angle λn−Δβ obtained by subtracting the error angle from the integer) and dividing the quotient obtained by adding 1 to the quotient. And calculating means for determining the target count value CNn counted from the reference position to the ignition position of each cylinder to be equal to or less than the calculated maximum target count value. The maximum target count value CNnmax is given by the following equation. Here, int means that only the whole number is obtained by rounding down the fractional part of the quotient.

CNnmax = int {(λn−Δβ) / θu} +1 (1)
As described above, the angle between the crank angle position when the reference signal is generated and the generation position of the first crank angle signal first counted by the crank angle signal counting means is detected as the error angle Δβ. The target count value of the crank angle signal is obtained by using the angle λn−Δβ obtained by subtracting the error angle from the angle λn from the reference position to the ignition position θin of each cylinder calculated by the ignition position calculation means and the unit angle θu. If it is determined, it is possible to prevent the phase difference Δβ between the reference signal and the crank angle signal from appearing as an ignition position detection error, so that the ignition position can be accurately controlled.

  The error angle detection means includes a time t1 from when the reference signal is generated until the first crank angle signal is generated, and a second time after the crank angle sensor generates the first crank angle signal. From the time t2 until the generation of the first crank angle signal and the unit angle .theta.u, the error angle .DELTA..beta.

Δβ = θu · t1 / t2 (2)
The target count value CNn may be determined to be equal to or less than the maximum target count value CNnmax. However, the target count value is set to the maximum count value at extremely low speeds where the crankshaft rotational speed greatly varies with changes in the engine stroke. Is preferably set equal to. In the medium to high speed region where the rotation speed is stable, the target count value can be determined to be smaller than the maximum target count value.

  Also, in the middle and high speed rotation region of the engine, the ignition position is detected by starting the measurement of the ignition timer measurement time at the ignition position measurement start position without counting the crank angle signal and using the reference position as the ignition position measurement start position. You may make it do.

  The remaining angle calculation means ignites nth using the following calculation formula from the angle λn−Δβ obtained by subtracting the error angle from the angle λ from the reference position to the ignition position, the target count value CNn, and the unit angle θu. The remaining angle θxn remaining before the target ignition position of the cylinder to be operated can be calculated.

θxn = (λn−Δβ) − (CNn−1) × θu (3)
The ignition timer measurement time calculation means calculates the following calculation formula from the generation interval (time) to of the crank angle signal immediately before the count value of the crank angle signal reaches the target count value, the remaining angle θxn, and the unit angle θu. Thus, the ignition timer measurement time tin can be calculated.

  tin = (θxn / θu) × to (4)

  As described above, according to the present invention, the angle between the crank angle position when the reference signal is generated and the generation position of the first crank angle signal that is first counted by the crank angle signal counting means is determined as an error. The target count value of the crank angle signal using the angle λn−Δβ obtained by subtracting the error angle from the angle λn from the reference position to the ignition position calculated by the ignition position calculation means and the unit angle θu. Therefore, the phase difference between the reference signal and the crank angle signal is prevented from appearing as an ignition position detection error, and the ignition position can be accurately controlled.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 shows a configuration example of hardware used in an embodiment of the present invention. In this example, a three-cylinder two-cycle internal combustion engine is ignited. In FIG. 1, 1 is a magnet generator driven by an internal combustion engine, 2 is an ignition circuit, and 3 is a control unit for controlling the ignition circuit.

  The magnet generator 1 includes an iron core having a magnet rotor 5 formed by attaching a permanent magnet to the inner periphery of a flywheel 4 attached to a crankshaft of an internal combustion engine, and a magnetic pole portion facing the magnetic pole of the magnet rotor. It is a well-known thing comprised with the stator formed by winding a power generation coil, and one power generation coil provided in the stator side is used as the exciter coil 6. One end of the exciter coil 6 is grounded.

  On the outer periphery of the flywheel 4, there is provided an arc-shaped reluctator 4a extending with a predetermined polar arc angle in the circumferential direction of the flywheel, and a signal generator 7 is provided in the vicinity of the outer periphery of the flywheel. The signal generator 7 is a well-known one having a signal coil wound around an iron core having a magnetic pole portion facing the reluctor 4a, and a permanent magnet magnetically coupled to the iron core. When the side edge and the rear end side edge are detected, pulses Vs1 and Vs2 having different polarities are generated as shown in FIG. In the present embodiment, the signal is generated when the polar arc angle of the reluctator 4a is set to 120 degrees and the rotation angle position of the crankshaft of the engine coincides with the position θ1 of 120 degrees before the top dead center of the first cylinder. The detector 7 detects the edge on the front end side in the rotation direction of the reluctator 4a, and generates a pulse Vs1 of a threshold value Vt or more. In this example, the pulse Vs1 is used as a reference signal, the crank angle position (position 120 ° before the top dead center of the first cylinder) θ1 where the reference signal Vs1 is generated is set as a reference position, and this reference position will be described later. The counting start position is used to start counting the crank angle signal Vcr.

A ring gear 8 for meshing a pinion gear attached to a starter motor that is driven when the engine is started is attached to the outer periphery of the flywheel 4. The ring gear 8 is made of a ferromagnetic material (iron), and a crank angle sensor 9 is disposed in the vicinity of the ring gear. The crank angle sensor 9 is configured in the same manner as the signal generator 7 and detects the edge of each tooth of the ring gear 8 to generate pulse signals having different polarities. In this example, the ring gear 8 has 100 teeth, and the interval (unit angle) between adjacent teeth is 3.6 degrees.
The ignition circuit 2 includes first to third cylinder ignition coils IG1 to IG3, first to third cylinder primary current control circuits PC1 to PC3 for controlling primary currents of these ignition coils, and an internal combustion engine. And ignition plugs P1 to P3 to which high voltage for ignition is applied from ignition coils IG1 to IG3.

  Each ignition coil has a primary coil W1 and a secondary coil W2 commonly connected at one end, and the other end of the secondary coil W2 is connected to a non-grounded terminal of the ignition plug of the corresponding cylinder through a high voltage cord. The other end of the primary coil W1 is grounded.

  The primary current control circuits PC1 to PC3 are well-known capacitor discharge type circuits. Each primary current control circuit has an ignition capacitor C1 having one end connected to one end of the primary coil of the corresponding ignition coil, a cathode connected to the other end of the ignition capacitor C1, and an anode being the non-grounded side of the exciter coil 6. The diode D1 connected to the terminal, the thyristor Th connected with the cathode facing the ground side between the other end of the ignition capacitor C1 and the ground, and the cathode grounded between one end of the primary coil of the corresponding ignition coil and the ground The first and third cylinder ignition signal input terminals a1 to a3 are derived from the gates of the thyristors Th of the primary current control circuits PC1 to PC3, respectively. . These input terminals a1 to a3 are respectively supplied with ignition signals from the control unit 3 at the ignition positions of the first to third cylinders of the engine.

  In the illustrated ignition circuit 2, when the exciter coil 6 outputs a positive half-wave voltage in the direction indicated by the arrow, the ignition capacitor C1 of each primary current control circuit is charged to the illustrated polarity through the diodes D1 and D2. Is done. When the ignition signal Vi is given from the control unit 3 to the ignition signal input terminals a1 to a3 at the ignition positions of the first to third cylinders of the internal combustion engine, the thyristors Th of the primary current control circuits PC1 to PC3 are turned on. Therefore, the electric charge of each ignition capacitor C1 is discharged through the corresponding thyristor Th and the corresponding primary coil W1 of the ignition coil. Thus, when the charge of the ignition capacitor C1 is discharged through the primary coil of the corresponding ignition coil in the primary current control circuit for each cylinder, a high voltage for ignition is induced in the secondary coil W2 of each ignition coil, The high voltage for ignition is applied to the ignition plug of each cylinder. As a result, spark discharge is generated at the ignition plug of each cylinder, and the engine is ignited.

  The control unit 3 includes a microcomputer 3A and waveform shaping circuits 3B and 3C. The microcomputer 3A includes at least a CPU 301, a 16-bit timer 302, an interrupt control circuit 303, a latch circuit 304, a ROM and a RAM (not shown), and an output and crank angle of the signal generator 7. The output of the sensor 9 is input to the interrupt control circuit 303 through the waveform shaping circuits 3B and 3C, respectively. The 16-bit timer 302 is a 1-bit 1 μsec free-run timer.

  The waveform shaping circuit 3B converts the reference signal Vs1 generated at the reference position by the signal generator 7 into a signal that can be recognized by the microcomputer, and inputs the signal to the interrupt control circuit 303. The waveform shaping circuit 3C is composed of a flip-flop circuit or the like, and a pair of pulses generated when the crank angle sensor 9 detects edges at both ends of each tooth of the ring gear is a signal corresponding to the width of the ring gear teeth. This is converted into a rectangular wave crank angle signal Vcr having a width. An example of the crank angle signal Vcr output from the waveform shaping circuit 3C is shown in FIG. In FIG. 6, # 1 TDC to # 3 TDC indicate the top dead center of the first cylinder to the third cylinder (the crank angle position when the pistons of the first cylinder to the third cylinder respectively reach the top dead center). . In the illustrated example, there is a phase difference (error angle) Δβ between the reference signal Vs1 and the crank angle signal Vcr.

  The interrupt control circuit 303 receives a signal obtained by shaping the reference signal from the waveform shaping circuit 3B and when a crank angle signal is inputted from the waveform shaping circuit 3C (at the rising edge of the crank angle signal). The latch circuit 304 causes the measured value (time) of the free-run timer 302 at that time to be latched, and interrupts the processing of the main routine being executed by the CPU 301 to perform predetermined interrupt processing. The priority of interrupt processing is higher for interrupts based on the reference signal than for interrupts based on the crank angle signal. When the reference signal is generated while the crank angle signal is being generated, an interrupt request based on the crank angle signal is generated. , And the interrupt request based on the reference signal is accepted first, and after the interrupt processing based on the reference signal is completed, the unprocessed interrupt processing based on the crank angle signal generated earlier is executed. .

  The CPU 301 executes the main routine shown in FIG. 2 according to the program stored in the ROM. In this main routine, when the microcomputer is started, first, each part is initialized in step 1, and then in step 2, the engine speed is calculated, the required ignition timing data determined by the user, the speed, The target ignition position of each cylinder is calculated according to the output of the sensor that detects the control condition. The target ignition position θin of each cylinder is calculated as an angle λn from the reference position θ1 to the target ignition position θin. The rotational speed data and the target ignition position data are updated at regular intervals. In this embodiment, since the internal combustion engine has three cylinders, an angle λ1 from the reference position θ1 to the ignition position of the first cylinder to an angle λ3 from the ignition position of the third cylinder is calculated.

  When the CPU receives an interrupt request based on a reference signal, the CPU executes the reference signal interrupt shown in FIG. In this reference signal interruption, first, in step 1, the number of occurrences of interruption by the crank angle signal between the time when the previous reference signal was generated and the time when the current reference signal was generated (the count value of the crank signal) is stored. In step 2, it is determined whether or not the crank angle signal generation time and the reference signal generation time match. As a result, when it is determined that the generation time of the crank angle signal and the generation time of the reference signal do not coincide with each other, the process proceeds to step 3 to determine whether or not the crank angle signal is generated before the reference signal. judge. As a result, when it is determined that the crank angle signal is not generated before the reference signal, it is determined in step 4 that the condition 1 is satisfied, and a flag indicating that the condition 1 is satisfied is set. The flag indicating that other conditions are satisfied is cleared and the process returns to the main routine.

  When it is determined in step 3 that the crank angle signal is generated before the reference signal, it is determined in step 5 that the condition 2 is satisfied, and a flag indicating that the condition 2 is satisfied is set. Then, the flag indicating that other conditions are satisfied is cleared and the process returns to the main routine. When it is determined in step 2 that the generation time of the crank angle signal and the generation time of the reference signal coincide with each other, it is determined in step 6 that the condition 3 is satisfied, and that the condition 3 is satisfied. Set the flag to clear, clear the flag indicating that other conditions are met, and return to the main routine.

  Conditions 1 to 3 are satisfied in the following cases.

  As shown in FIGS. 7A and 7B, the condition 1 is when there is only an interrupt request based on the reference signal, or when the interrupt request based on the reference signal is faster than the interrupt request based on the crank angle signal. To establish. When the condition 1 is satisfied, an interrupt request based on a crank angle signal received after completion of the interrupt processing based on the reference signal (interrupt performed at the rising edge of the crank angle signal Vcr indicated by adding the circled number 1 to FIG. 7B). It is recognized that the first crank angle signal has been generated after the reference signal has been generated (after the counting of the crank angle signal has started). In FIG. 7, the horizontal axis represents the crank angle θ, but the phase relationship between the reference signal and the crank angle signal is determined by the generation time of the reference signal and the crank angle signal latched by the latch circuit 304 ( The time at which the interruption by the reference signal is applied and the time at which the interruption by the crank angle signal is applied).

  When the condition 1 is satisfied, the interrupt processing by the reference signal is executed in the section a indicated by hatching in FIG. Also, during the interval b1 shown in the figure, the interrupt processing by the first crank angle signal is executed, and thereafter, every time the second and subsequent crank angle signals rise until the next reference signal is generated, the interval b2 , B3,... Are interrupted by a crank angle signal.

  In condition 2, as shown in FIGS. 8A and 8B, the crank angle signal made an interrupt request before the reference signal, but the reference signal was generated while the crank angle signal was being generated. This is established when an interrupt request based on a reference signal is received first according to priority. When the condition 2 is satisfied, the crank angle signal generated prior to the interrupt request based on the reference signal is not counted, and the interrupt request is generated based on the crank angle signal generated first after the reference signal is generated (the circled number in FIG. 8B). It is recognized that the first crank angle signal Vcr has been generated after the generation of the reference signal when there is an interrupt request executed at the rising edge of the crank angle signal Vcr indicated by 1.

  When the condition 2 is satisfied, the interrupt processing by the reference signal is executed in the section a shown in FIG. 8E, and the rise of the crank angle signal generated immediately before the reference signal is generated in the section bo shown in the figure. An unprocessed interrupt process that was supposed to be executed at the rise of the crank angle signal generated at the crank angle position θa shown in FIG. 8B is executed. In addition, in the interval b1 immediately after the first crank angle signal rises, the interrupt processing by the first crank angle signal is executed, and until the next reference signal is generated, the second and subsequent crank angle signals are Each time it rises, an interruption by a crank angle signal is executed in the sections b2, b3,.

  Condition 3 is when the crank angle signal and the reference signal are generated at the same time as shown in FIGS. 9A and 9B, but an interrupt request based on the crank angle signal is accepted according to priority. In this case, assuming that there is no phase difference between the crank angle signal and the reference signal, an interrupt request by the crank angle signal generated at the same time as the reference signal (rising edge of the crank angle signal Vcr indicated by the circled number 1 in FIG. 9B). It is recognized that the first crank angle signal has been generated after the generation of the reference signal (after the counting start position).

  When the condition 3 is satisfied, the interrupt process by the reference signal is executed in the section a shown in FIG. 9E, and then the interrupt process by the first crank angle signal is executed in the section b1. After that, every time the second and subsequent crank angle signals rise until the next reference signal is generated, an interruption by the crank angle signal is executed in the sections b2, b3,.

  After the interruption by the reference signal is completed, an interruption request by the crank angle signal is accepted, and the crank angle signal interruption routine shown in FIG. 4 is executed. In this interrupt routine, first, in step 1, the interrupt counter is incremented by 1 (1 is added to the contents of the RAM for storing the count value). Next, in step 2, it is determined whether or not the count value of the counter is 1. If the count value of the counter is 1, the current crank angle signal interrupt is an interrupt that is performed first after the reference signal is generated. In step 3, it is determined whether or not it is determined in step 3 that the condition 3 is satisfied by the reference signal interruption in FIG. As a result, when the condition 3 is not satisfied, it is determined at step 4 whether the condition 2 is satisfied. When the condition 2 is not satisfied, the first time from the time when the reference signal is generated at the step 5 is determined. The time t1 until the time when the crank angle signal is generated is calculated and the process returns to the main routine.

  When it is determined in step 4 that the condition 2 is satisfied, the current interrupt request is generated before the reference signal generation timing, and the level between the crank angle signal generated this time and the reference signal is determined. Since it is not necessary to measure the phase difference, the count value of the counter is cleared (set to 0) in step 6, and then the flag indicating that the condition 2 is satisfied is cleared in step 7 and this interrupt is terminated. .

  When it is determined in step 3 that the condition 3 is satisfied (the generation time of the reference signal is coincident with the generation time of the first crank angle signal), the condition between the crank angle signal generated this time and the reference signal is determined. Since it is not necessary to measure the phase difference between them (it is not necessary to correct the phase difference), this interrupt is terminated without doing anything.

  When it is determined in step 2 that the count value of the counter is not 1, and when it is determined in step 8 that the count value of the counter is 2 (when it is determined that the current interrupt is an interrupt due to the second crank angle signal) Then, in step 9, it is determined whether or not the condition 3 is satisfied. If the condition 3 is not satisfied, the second crank angle signal is detected in step 10 from the generation time of the first crank angle signal. The time t2 until the occurrence time is calculated. Next, in step 11, the phase difference (error angle) Δβ between the reference signal and the first crank angle signal is calculated by the equation Δβ = θu · t1 / t2 [the above equation (2)]. By subtracting the error angle Δβ from the angle λn from the reference position to the target ignition position θin, the error angle Δβ can be corrected (the influence of the error angle is eliminated).

  Next, at step 12, in the calculation formula CNn = int {(λn−Δβ) / θu} +1, λn is set to λ1, λ2 and λ3, and after the reference position (measurement start position) θ1, the target of the first to third cylinders The target count values CN1 to CN3 of the crank angle signal to be counted between the ignition positions θi1 to θi3 are calculated. Here, the target count value is assumed to be equal to the maximum target count value CNnmax in the equation (1).

  In step 12, the arithmetic value θx = (λn−Δβ) − (CNn−1) × θu is set such that λn is λ1 to λ3, the target count value CNn is CN1 to CN3, and the count value of the crank angle signal is the target. The remaining angles θx1 to θx3 from the respective positions reaching the count values CN1 to CN3 to the target ignition positions θi1 to θi3 are calculated, respectively, and then the process returns to the main routine.

  If it is determined in step 9 that the condition 3 is satisfied, the phase difference Δβ between the reference signal and the first crank angle signal is set to 0 in step 13 and then the process proceeds to step 12 to proceed to the target count values CN1 to CN3. And the remaining angles θx1 to θx3 are calculated.

  If it is determined in step 8 that the counter value is not 2 (the crank angle signal generated this time is the third or later crank angle signal), the process proceeds to step 14 where the counter value Sk is set to the target count value CN1. It is determined whether or not they are equal. If they are not equal, the process returns to the main routine to continue counting the crank angle signal. When it is determined in step 14 that the count value of the counter is equal to the target count value CN1, the routine proceeds to step 15 where the ignition timer measurement time ti1 = (θx1) for measuring the target ignition position of the first cylinder from the remaining angle θx1. /.Theta.u).times.to is calculated, and in step 16, the ignition timer measurement time ti1 is set in the ignition timer and the measurement is started. Thereafter, in step 17, the target count value CNn and the remaining angle θxn are updated to values for the second cylinder in preparation for ignition of the next second cylinder, and then the process returns to the main routine.

  When the ignition timer completes the measurement of the ignition timer measurement time ti1, an ignition timer interrupt (not shown) is executed, and a process of giving an ignition signal to the thyristor Th of the primary current control circuit PC1 of the first cylinder is performed. As a result, the charge of the ignition capacitor C1 of the primary current control circuit PC1 of the first cylinder is discharged through the primary coil of the ignition coil IG1, and an ignition operation is performed in the first cylinder of the engine.

  The crank angle signal interruption of FIG. 4 is continued even after the first cylinder is ignited, and it is assumed that the count value Sk of the counter becomes equal to the target count value CN2 for detecting the ignition position of the second cylinder in step 14. When the determination is made, steps 15 and 16 are executed, the ignition timer measurement time ti2 is set in the ignition timer, and the ignition position of the second cylinder is measured. Thereafter, in step 17, the target count value CNn and the remaining angle θxn are updated to the values for the third cylinder in preparation for the ignition of the third cylinder, and the ignition of the second cylinder is completed when the ignition timer completes the measurement of the ignition position measurement time. Is done. Thereafter, the same operation is repeated to ignite the third cylinder.

  7 to 9, (C) shows the count value Sk of the crank angle signal counting means, and this count value is incremented by 1 every time the rising of the crank angle signal is detected. 7 to 9, (D) indicates the measured value St of the ignition timer. The ignition timer starts measuring the ignition position measurement time tin at the crank angle position θ2n at which the count value of the crank angle signal reaches the target value, and when the measurement is completed, the target ignition position θin (in FIGS. 7 to 9) Detects n = 1).

  In the present invention, a phase difference (error angle) Δβ between the reference signal Vs1 and the first crank angle signal is obtained, and a value obtained by subtracting the error angle Δβ from the angle λn from the reference position to the target ignition position is obtained. Since the target count value of the crank angle signal is obtained by dividing by the unit angle θu, the target count value of the crank angle signal for detecting the target ignition position is determined without being affected by the error angle Δβ. be able to. Therefore, by starting the ignition timer when the count value of the crank angle signal reaches the target count value and measuring the remaining angle to the ignition position, the target ignition position can be obtained accurately, and the ignition position control Can be done accurately.

  For comparison with the ignition position measurement operation in the conventional ignition device shown in FIGS. 5C and 5D, the ignition position measurement operation in the ignition device according to the present invention is shown in FIG. . In the case of the conventional ignition device in which the ignition position is detected by using both the counting operation of the crank angle signal and the timing operation by the ignition timer, as shown in FIG. Although the actual ignition position θi1 ′ may deviate from the target ignition position θi1 due to the effect of Δβ, according to the present invention, the target ignition position θi1 can be accurately detected without being affected by the error angle Δβ, The ignition position can be accurately controlled.

  In the present embodiment, step 2 of the main routine of FIG. 2 constitutes an ignition position calculation means for calculating the ignition position of the internal combustion engine, and the step of the interrupt routine of FIG. 4 is permitted to be executed after the reference signal is generated. 1 constitutes a crank angle signal counting means for counting the crank angle signal with the crank angle position where the reference signal is generated as the counting start position.

  Further, in step 12 of the interrupt routine in FIG. 4, the number of crank angle signals to be counted by the crank angle signal generating means while the crankshaft rotates from the reference position to the ignition position calculated by the ignition position calculating means is set as the target count value. The target count value determining means to be determined and the angle from the ignition position measurement start position to the ignition position with the crank angle position when the count value counted by the crank angle signal counting means reaches the target count value as the ignition position measurement start position And a remaining angle calculating means for calculating as a remaining angle θxn.

  Further, step 15 in FIG. 4 constitutes an ignition timer measurement time calculating means for obtaining the time required for the crankshaft to rotate the remaining angle as an ignition timer measurement time, and step 16 and ignition timer in FIG. An ignition timer interrupt (not shown) that generates an ignition signal when the measurement is completed causes the ignition timer to start measuring the ignition timer measurement time at the ignition position measurement start position, and the ignition timer completes the measurement of the ignition timer measurement time An ignition signal generating means for generating an ignition signal when the engine is operated.

  Further, in step 11 of FIG. 4, the angle between the crank angle position when the reference signal is generated and the generation position of the first crank angle signal first counted by the crank angle signal counting means is defined as an error angle Δβ. An error angle detection means for detecting is constructed. In step 12 of FIG. 4, the angle λn−Δβ obtained by subtracting the error angle from the angle λn from the reference position to the ignition position calculated by the ignition position calculation means is divided by the unit angle θu. The maximum target count value calculating means for calculating the value obtained by adding 1 to the quotient obtained by rounding off the decimal point as the maximum target count value is configured, and the maximum target calculated by the maximum target count value calculating means The target count value determining means is configured to determine the count value as the target count value.

It is the circuit diagram which showed the structural example of the hardware used by embodiment of this invention. It is a flowchart which shows the algorithm of the main routine which a microcomputer performs in embodiment of FIG. It is a flowchart which shows the algorithm of the reference signal interruption routine which a microcomputer performs in embodiment of FIG. It is a flowchart which shows the algorithm of the crank angle signal interruption routine which the microcomputer performs in embodiment of FIG. It is explanatory drawing which showed the operation | movement for detecting an ignition position in the ignition device for internal combustion engines comparing the case by a prior art example, and the case by embodiment of this invention. FIG. 3 is a waveform diagram showing a waveform of a crank angle signal obtained from a waveform shaping circuit that shapes the waveform of a reference signal generated by a signal generator and the output of a crank angle sensor in an embodiment of the present invention. It is operation | movement explanatory drawing explaining operation | movement when the condition 1 is satisfied between the reference signal and the crank angle signal in the embodiment of the present invention. It is operation | movement explanatory drawing explaining operation | movement when the condition 2 is materialized between a reference signal and a crank angle signal in embodiment of this invention. It is operation | movement explanatory drawing explaining operation | movement when the condition 3 is materialized between a reference signal and a crank angle signal in embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Magnet generator 2 Ignition circuit 3 Control unit 3A Microcomputer 3B Waveform shaping circuit 3C Waveform shaping circuit 7 Signal generator 9 Crank angle sensor

Claims (2)

A signal generator for generating a reference signal at a specific crank angle position of the internal combustion engine, a crank angle sensor for generating a crank angle signal each time the crankshaft of the internal combustion engine rotates by a unit angle θu, and an ignition position of the internal combustion engine Ignition position calculating means for calculating the crank angle signal counting means for counting the crank angle signal with the crank angle position where the reference signal is generated as a counting start position, and the ignition position calculating means for calculating the crankshaft from the reference position. Target count value determining means for determining, as a target count value, the number of crank angle signals to be counted by the crank angle signal generating means while rotating to the ignition position calculated by the above, and the count value counted by the crank angle signal counting means The crank angle position when the engine reaches the target count value is set as the ignition position measurement start position, and from the ignition position measurement start position to the ignition position. A remaining angle calculating means for calculating the remaining angle as a remaining angle, an ignition timer measuring time calculating means for obtaining a time required for the crankshaft to rotate the remaining angle as an ignition timer measuring time, and an ignition position measurement start position. An ignition signal generating means for causing an ignition timer to start measuring the ignition timer measurement time, and generating an ignition signal when the ignition timer completes the measurement of the ignition timer measurement time; and the internal combustion engine when the ignition signal is generated An ignition device for an internal combustion engine comprising an ignition circuit for generating a high voltage for ignition applied to an ignition plug attached to a cylinder of
The target count value determining means calculates an error angle as an angle between a crank angle position when the reference signal is generated and a generation position of the first crank angle signal first counted by the crank angle signal counting means. An error angle detection means for detecting as Δβ, and an angle λ−Δβ obtained by subtracting the error angle from an angle λ from the reference position to the ignition position calculated by the ignition position calculation means is divided by the unit angle θu. Maximum target count value calculating means for calculating, as a maximum target count value, a value obtained by rounding down the decimal point of a value obtained by adding 1 to the obtained quotient, and determining the target count value to be equal to or less than the maximum target count value That is structured as
An ignition device for an internal combustion engine. The error angle detection means includes
The time t1 from the generation of the reference signal to the generation of the first crank angle signal, and the second crank after the crank angle sensor generates the first crank angle signal. The error angle Δβ is calculated from the time t2 until the generation of the angle signal and the unit angle θu, by calculating the error angle Δβ by an equation of Δβ = θu · t1 / t2. ,
The ignition device for an internal combustion engine according to claim 1.

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