JP2006274853A - Ignition control device for engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a trouble such as misfire caused by shortage of ignition energy. <P>SOLUTION: An AC generator 10 periodically repeats charge and discharge electricity along with rotation of an engine output shaft. An ignition coil 30 is energized by power fed from the AC generator 10. When a predetermined rotating zone of a predetermined engine output shaft is defined as an energization zone, a microcomputer 27 energizes the ignition coil 31 in the energization period. In this case, particularly, each of a charge period of the AC generator 10 and the energization period of the ignition coil 30 is set so that there is overlap between the periods. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an engine ignition control device.

  Conventionally, vehicles equipped with an AC generator that generates electricity by periodically charging and discharging as the output shaft of the engine rotates are put into practical use. Power is supplied from the generator, and various electric components are driven by the power supply. As for the ignition system, the primary coil of the ignition coil is energized by power supplied from the AC generator, and then energized and cut off at a predetermined timing, thereby inducing a high voltage in the secondary coil and performing an ignition operation (for example, patents). Reference 1).

However, the existing apparatus has the following problems. That is, when the ignition coil is energized, the ignition energy is accumulated by the energization, but at that time, if the power supply from the AC generator is not sufficient, the ignition energy is insufficient. Further, misfire or the like occurs due to insufficient ignition energy, resulting in poor combustion.
JP-A-5-1650

  The main object of the present invention is to provide an engine ignition control device capable of preventing problems such as misfire due to a shortage of ignition energy.

  The engine ignition control device of the present invention is premised on an AC generator, an ignition coil, and an energization control means, and the AC generator periodically repeats charging and discharging as the engine output shaft rotates. Generate electricity. The energization control means sets a predetermined rotation section of the engine output shaft as a current-carrying period and conducts electricity to the ignition coil during the current-carrying period. At this time, when the engine output shaft reaches a predetermined rotational position, the ignition coil is energized by the power supply from the AC generator, and then the energization is interrupted and ignition is performed at the timing when the energization period elapses.

  In the above configuration, in particular, since the respective periods are set so that the charging period by the AC generator and the energization period overlap, it is possible to sufficiently secure ignition energy when the ignition coil is deenergized (that is, ignition timing). Accordingly, it is possible to prevent problems such as misfire due to a shortage of ignition energy.

  There are vehicles that are not equipped with a battery, such as motorcycles. In such a battery-free vehicle, if the power supply voltage is low when the engine is started, there is a high possibility that the ignition energy will be insufficient, and the engine startability will be reduced due to the lack of ignition energy. On the other hand, in the configuration in which the ignition coil is energized in the predetermined rotation section at least when the engine is started, the charging period by the AC generator and the energization period of the ignition coil (predetermined rotation section) overlap as described above. By setting these periods, sufficient ignition energy can be secured even when the engine is started. As a result, the startability of the engine can be improved.

  As a specific specification for overlapping the charging period of the alternator and the energization period of the ignition coil, the charging of the alternator and the energization of the ignition coil are performed in the engine idling operation state or an equivalent operation state. It is preferable that the overlapping overlapping period is 50% or more of the energizing period. That is, when the energization period is X and the overlap period is Y, the ratio (Y / X) is preferably 50% or more. More preferably, the ratio (Y / X) is 70% or more.

  In the second invention, the detecting means detects the start of charging of the AC generator. The energization start means starts energization of the ignition coil on condition that the start of charging is detected by the detection means. According to this configuration, the ignition coil can be energized while being overlapped with charging by the AC generator. Therefore, sufficient ignition energy can be secured when the ignition coil is cut off (that is, ignition timing), and malfunctions such as misfire due to insufficient ignition energy can be prevented.

  In a vehicle not equipped with a battery such as a motorcycle, there is a high possibility that the ignition energy will be insufficient if the power supply voltage is low when the engine is started. However, as described above, the ignition coil is subject to the detection of the charging start by the detection means. By starting the energization, sufficient ignition energy can be secured even when the engine is started. As a result, the startability of the engine can be improved.

  Further, it is preferable that a power storage means such as a capacitor for storing power by power supply from the AC generator is provided in the power supply line of the ignition coil. Thereby, even when the AC generator generates power by repeating charging and discharging, stable power supply to the ignition coil is possible.

(First embodiment)
DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, an embodiment of the invention will be described with reference to the drawings. In this embodiment, an example of application to an engine control system for a motorcycle is described, and FIG. 1 shows an outline of the configuration. In this example, the motorcycle is not equipped with a battery, and an initial rotation is applied to the crankshaft of the engine when the user kicks the kick starter, and the engine is started accordingly. It is like that.

  In FIG. 1, an AC generator 10 is one that generates AC power when a driving force is applied from an engine crankshaft (not shown). Specifically, the AC generator 10 is composed of a single-phase magneto generator. Yes. A lighting device 11 such as a headlight or a rear light is driven by electric power generated by the AC generator 10. The AC generator 10 has a plurality of magnetic poles made of permanent magnets, and has, for example, 10 or 12 magnetic poles. In the AC generator 10, charging and discharging are alternately repeated at a cycle according to the number of magnetic poles during power generation.

  The power of the AC generator 10 is adjusted to a voltage of, for example, 14 V by the regulator 12 and then supplied to an ECU (electronic control unit) 20 via an ignition switch (hereinafter referred to as IG switch) 13. At this time, the electric power supplied from the regulator 12 is taken into the ECU 20 through a power supply line including the power supply terminal T1.

  In the ECU 20, a capacitor 22 as a power storage unit is connected to the power supply terminal T <b> 1 via a diode 21. The ignition coil 30 is connected to the primary coil 30a.

  Further, a capacitor 24 is connected to the power supply terminal T1 via a diode 23, and a terminal side at which the capacitor 24 has a high potential (that is, the cathode side of the diode 23) is connected to a power supply IC 25. The power supply IC 25 constitutes a power supply circuit for generating a drive voltage VCC (for example, 5 V) for the microcomputer.

  A capacitor 26 is connected to the output side of the power supply IC 25 and a microcomputer 27 is connected. The microcomputer 27 constitutes a well-known logical operation circuit including a CPU, a ROM, a RAM, and the like. A detection signal of the crank angle sensor 33 is input to the microcomputer 27 via a waveform shaping circuit (not shown). At the same time, a detection signal of a load detection sensor such as an air flow meter is input in a timely manner. The microcomputer 27 corresponds to energization control means. The crank angle sensor 33 is a sensor that detects the rotational position of the crankshaft at every predetermined angle (for example, 30 ° CA), and the microcomputer 27 sends a pulsed NE signal (rotation angle signal) at a predetermined angular period through a waveform shaping circuit. ) Is entered.

  The microcomputer 27 calculates an optimal ignition timing based on the engine operating state at each time and generates an ignition control signal corresponding to the ignition timing. This ignition control signal is output to the transistor 28. The transistor 28 has a collector connected to the primary coil 30a of the ignition coil 30 via the output terminal T3, and an emitter grounded. A spark plug 31 is connected to the secondary coil 30 b of the ignition coil 30.

  When the transistor 28 is turned on by the ignition control signal output from the microcomputer 27, the primary coil 30a of the ignition coil 30 is energized accordingly. After that, when the transistor 28 is turned off, the energization of the primary coil 30a is cut off, and accordingly, a high voltage is induced in the secondary coil 30b, and an ignition spark is generated between the counter electrodes of the spark plug 31.

  When the engine is started, the ignition coil 30 is energized in a predetermined predetermined rotation interval. Specifically, the energization start timing and the energization cutoff timing are set in synchronization with the NE signal. The In other words, each pulse of the NE signal is numbered according to the crank angle position, and energization of the ignition coil 30 is started upon arrival of a predetermined nth pulse (energization start pulse). The energization is interrupted by the arrival of the n + αth pulse (energization end pulse). Then, after the start of the engine is completed, the ignition timing control is shifted from fixed ignition to variable ignition.

  By the way, when the ignition coil 30 is energized, ignition energy is accumulated by the energization, but at that time, if the power supplied from the AC generator 10 is not sufficient, the ignition energy is insufficient, resulting in poor combustion. Is concerned. Therefore, in the present embodiment, in order to secure ignition energy, the respective periods are set so that the charging period by the AC generator 10 and the coil energization period overlap.

  By adjusting the magnetization phase of the AC generator 10, the charging period and the coil energization period by the AC generator 10 are preferably overlapped. That is, the AC generator 10 has an annular permanent magnet with SN magnetic poles alternately magnetized in the radial direction, and the magnetization phase of the permanent magnet is set at a crank angle position corresponding to the coil energization period. Configure to correspond.

  Next, the power generation operation by the AC generator 10 and the ignition operation by the ignition coil 30 will be described more specifically with reference to the time chart of FIG. 2A shows a voltage waveform during power generation by the AC generator 10, FIG. 2B shows an ignition output waveform, and FIG. 2C shows an NE signal. However, (a) shows the waveform after voltage adjustment by the regulator 12. (C) shows only the rising edge of the NE signal.

  The voltage waveform of the AC generator 10 is a waveform in which charging and discharging are repeated at a constant cycle, and charging and discharging are basically repeated at a cycle of 45 ° CA. The rising edge of the NE signal occurs every 30 ° CA. At timing t1, energization of the ignition coil 30 is started based on a predetermined energization start NE pulse. At timing t2, energization is interrupted based on a predetermined energization end NE pulse, and an ignition spark is generated by the energization interruption. At this time, the ignition energy can be secured by overlapping the charging period of the AC generator 10 and the coil energization period.

  In this case, as shown in FIG. 3, when the coil energizing period is X and the overlapping period in which the charging of the AC generator 10 and the coil energizing overlap is Y, the ratio (Y / X) is 50% or more. And good. More preferably, the ratio (Y / X) is 70% or more. In FIG. 3, (a) shows a case where the charging period of the alternator 10 completely overlaps with the coil energization period, and (b) shows that the alternator 10 is charged across the energization start timing of the ignition coil 30. (C) shows the case where the AC generator 10 is charged across the timing when the ignition coil 30 is energized.

  However, it is considered that the charging period of the AC generator 10 changes according to the engine rotation speed and the like, and shifts to the states (a) to (c) in FIG. For example, as the rotational speed increases, the state changes from (b) to (a) to (c). That is, the ratio (Y / X) varies depending on the operating state. Considering this, the ratio (Y / X) is small depending on the operating state, but the ratio (Y / X) is 50% or more at least in the idling operation state immediately after the engine start or the operation state corresponding thereto. And good.

  According to the embodiment described above in detail, the following excellent effects can be obtained.

  Since these periods are set so that the charging period by the AC generator 10 and the energization period of the ignition coil 30 overlap, sufficient ignition energy can be secured when the ignition coil 30 is de-energized (that is, ignition timing). Accordingly, it is possible to prevent problems such as misfire due to a shortage of ignition energy.

  In particular, since the charging period is set in accordance with the fixed ignition at the time of engine start, sufficient ignition energy can be secured even at the time of engine start, and the startability of the engine can be improved.

  In addition, since the capacitor 22 as the power storage means is provided in the power supply line for supplying power to the ignition coil 30, stable power is supplied to the ignition coil 30 when the AC generator 10 generates power by repeated charging and discharging. Supply becomes possible.

(Second Embodiment)
In the second embodiment, the charging start of the AC generator 10 is detected, and the energization of the ignition coil 30 is started based on the detection result. Hereinafter, the difference from the first embodiment will be mainly described.

  FIG. 4 shows a configuration of a detection circuit 40 for detecting the start of charging of the AC generator 10. The detection circuit 40 includes a transistor 41 and resistors 42 to 44, and a voltage waveform from the AC generator 10 is input to the base of the transistor 41. A constant voltage source (voltage VCC) is connected to the collector of the transistor 41, and a change in collector voltage associated with ON / OFF of the transistor 41 is input to the microcomputer 27. In this case, before the start of charging (during discharging), the transistor 41 is turned off and the microcomputer input is H. When the voltage value increases with the start of charging, the transistor 41 is turned on and the microcomputer input changes to L.

  FIG. 5 is a time chart showing a voltage waveform and an ignition output waveform of the AC generator 10. As shown in the figure, when charging of the AC generator 10 is started, the rising of the voltage waveform is detected, and energization of the ignition coil 30 is started (timing t11). Then, the energization is interrupted at a timing when a predetermined time has elapsed after the start of energization (timing t12).

  FIG. 6 is a flowchart showing the ignition control process. This process is executed by the microcomputer 27 at a predetermined time period. In FIG. 6, in step S <b> 11, it is determined based on the input signal from the detection circuit 40 whether or not it is the charging start timing. Further, in step S12, it is determined whether or not the start of energization of the current ignition coil 30 is permitted, that is, whether or not the current time is the timing immediately before the ignition of the compression stroke. And when both step S11 and S12 are YES, it progresses to step S13 and energization of the ignition coil 30 is started.

  As described above, according to the second embodiment, the ignition coil 30 can be energized while being overlapped with charging by the AC generator 10. Therefore, sufficient ignition energy can be secured when the ignition coil 30 is energized (that is, ignition timing), and problems such as misfire due to insufficient ignition energy can be prevented. In particular, even when the charging period of the alternator 10 with respect to the crank angle varies depending on the engine operating state, the charging period of the alternator 10 and the coil energization period can be reliably overlapped.

  In this case, sufficient ignition energy can be ensured even when the engine is started, and the startability of the engine can be improved.

  In the above embodiment, the capacitor 22 as the power storage means is provided in the power supply line for supplying power to the ignition coil 30, but this configuration is changed and the power supply line is directly connected to the ignition coil 30. Also good.

  In the above embodiment, an example of application to a motorcycle not equipped with a battery has been described. However, the present invention can also be applied to a vehicle equipped with a small (low capacity) battery. Even in such a case, effects such as securing of ignition energy can be obtained. In addition to motorcycles, it can also be applied to four-wheeled vehicles, small ships, agricultural equipment, and the like.

It is a block diagram which shows the outline of the apparatus in embodiment of invention. It is a time chart for demonstrating the electric power generation operation | movement by an alternating current generator, and the ignition operation | movement by an ignition coil. It is a time chart which shows the voltage waveform and ignition output waveform of an AC generator. It is a figure which shows the structure of a detection circuit. It is a time chart for demonstrating the electric power generation operation | movement by an alternating current generator, and the ignition operation | movement by an ignition coil. It is a flowchart which shows an ignition control process.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... AC generator, 20 ... ECU, 22 ... Capacitor, 27 ... Microcomputer, 30 ... Ignition coil, 31 ... Spark plug, 40 ... Detection circuit.

Claims (6)

An alternator that generates electricity by periodically charging and discharging as the engine output shaft rotates;
An ignition coil energized by power supplied from the AC generator;
An energization control means configured to energize the ignition coil during the energization period with a predetermined rotation interval of a predetermined engine output shaft as the energization period;
In an engine ignition control device comprising:
An engine ignition control device characterized in that each period is set so that a charging period by the AC generator and the energization period overlap each other.   2. The engine ignition control according to claim 1, wherein the ignition control unit is applied to a vehicle without a battery, and the energization control unit energizes the ignition coil in the predetermined rotation section at least when starting the engine. apparatus.   In an idle operation state of the engine or an equivalent operation state, an overlapping period in which charging of the AC generator overlaps with energization of the ignition coil is configured to be 50% or more of the energization period. The engine ignition control device according to claim 1 or 2. An alternator that generates electricity by periodically charging and discharging as the engine output shaft rotates;
An ignition coil energized by power supplied from the AC generator;
Detecting means for detecting the start of charging of the AC generator;
Energization start means for starting energization of the ignition coil on the condition that the start of charging is detected by the detection means;
An engine ignition control device comprising:   5. The method according to claim 4, which is applied to a vehicle without a battery, wherein the energization start means starts energization of the ignition coil on condition that the detection means detects the start of charging at least when the engine is started. Engine ignition control device.   The engine ignition control device according to any one of claims 1 to 5, wherein power storage means for storing electricity by power supply from the AC generator is provided in a power supply line of the ignition coil.

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