JP2007092605A - Multiple discharge type ignition device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a multiple discharge type ignition device which provides a comparatively high degree of freedom by the repetition of inductive discharge by making a primary coil a center tap type. <P>SOLUTION: An ignition device comprising a switching element for a primary coil drive on the primary side of an ignition coil is equipped with a plurality of switching elements for primary coil drive. The switching elements form a push-pull circuit by on-off control by a control part. The device alternately executes multiple ignition by turning on/off the plurality of switching elements at one ignition timing. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an internal combustion engine ignition device, and more particularly to a multiple discharge ignition type ignition device that performs ignition multiple times in one cycle.

In an internal combustion engine ignition device, a high energy ignition device is required in order to adapt to high-compression lean combustion as a recent measure against exhaust gas and fuel efficiency improvement. For example, it is described in Japanese Patent No. 28117781. As described above, a multiple discharge ignition device combining capacitive discharge and inductive discharge has been proposed. In addition, when detecting the ionic current in the multiple ignition device, since the power supply from the primary side is an alternating current, the waveform that can be directly acquired is a waveform that is counteracted by the alternating current that is supplied with the power. It is necessary to take out the waveform. As this means, for example, an ignition device described in Japanese Patent Laid-Open No. 9-196795 has been proposed.
Japanese Patent No. 2811781 Japanese Patent Laid-Open No. 9-196895

  However, although the above-mentioned conventional circuit can obtain excellent output performance for engine requirements, it requires a capacitive discharge circuit, and the control circuit for alternately repeating inductive discharge has an extremely large number of parts. There is a problem that it becomes complicated and expensive.

  Therefore, an object of the present invention is to obtain a multiple ignition device having a relatively high degree of freedom by repeating the inductive discharge using a center tap type primary coil.

  In order to solve the above-described problems, the present invention has the following configuration. That is, in an ignition device having a DC power source as a power source, an ignition coil including a primary coil and a secondary coil, and a switching element for driving the primary coil on the primary side of the ignition coil. And a plurality of switching elements for driving the primary coil, and the switching elements are controlled to be turned on and off by a control unit to constitute a push-pull circuit, and a plurality of switching is performed at one ignition timing by the push-pull circuit. A multiple discharge ignition device is characterized in that ignition is alternately performed a plurality of times by turning elements on and off.

  According to a second aspect of the present invention, a DC power source is used as a power source, and an ignition coil including a primary coil and a secondary coil is provided. The primary coil is formed of a center tap type coil, and two pieces are provided at both ends of the primary coil. The above switching elements are connected, and the switching elements are controlled to be turned on / off by the control unit to form a push-pull circuit. By the push-pull circuit, a plurality of switching elements are turned on / off at a single ignition timing to alternate. In the above-described configuration, the secondary coil is electromagnetically coupled to the primary coil to supply a high voltage to the spark plug, and the current path of the primary coil An IGBT may be disposed as a switching element.

  With the above configuration, the primary coil of the ignition coil of a normal current interrupting ignition device is a center tap type, two switching elements are arranged, and the ignition coil characteristics are adapted to high frequency, so that inductive discharge is output. A multiple discharge ignition device with high output energy that can be repeated while changing the voltage polarity alternately, and with a high degree of freedom in which the output voltage, the number of repetitions, and the switching period can be appropriately changed can be obtained at low cost.

  FIG. 1 is a block diagram of a multiple ignition type ignition device according to an embodiment of the present invention, and FIG. 2 is a waveform diagram at each point of FIG. In FIG. 1, a DC power source 2 is connected to a battery power source 1, a DC power source 2 and a center tap portion of a center tap type primary coil 15 are connected, and both ends of the center tap type primary coil 15 are alternately turned on / off. The collectors of switching elements 13 and 14 controlled to be turned off are connected, and the respective emitters are grounded. The gates of the switching elements 13 and 14 are connected to a control unit 4 composed of a flip-flop or the like. The control unit 4 is connected to the oscillation circuit 3, and the oscillation circuit 3 is connected to the igniter synchronous switch 11 via the input protection resistor 12. The igniter synchronous switch 11 is connected to the igniter input 10. The oscillation circuit 3 includes an oscillation circuit operational amplifier 9, an oscillation frequency timing resistor R1, timing resistors 7 and 8, and an oscillation frequency timing capacitor C1. In the above configuration, the switching elements 13 and 14 and the control unit 4 constitute a push-pull circuit. A spark plug 17 is connected to the secondary coil 16 of the ignition coil.

  The control for alternately turning on / off the switching elements 13 and 14 in the above configuration is constituted by the oscillation circuit 3 and the flip-flop 4 that start operation with the ignition signal as a trigger, and the secondary coil output voltage is the oscillation frequency of the oscillation circuit 3. It is configured to occur at 1/2 of the above.

  Next, the operation in the above configuration will be described. When an ignition signal is input to the igniter input 10 portion, the oscillation circuit 3 outputs a pulse signal at a frequency of 1 / (2 * C1 * R1) and inputs the pulse signal to the flip-flop 4. The flip-flop 4 inputs a signal as shown in FIG. 2 to the gates of the switching elements 13 and 14 in response to the input pulse signal.

  The switching elements 13 and 14 to which the gate signal is input are alternately turned on / off as shown in FIG. 2, and the primary coil currents I1-1 and I1-2 are supplied to the center tap type primary coil 15, respectively. . When viewed from the magnetically coupled secondary coil, the outskirts of I1-1 and I1-2 have current directions with different polarities, and the charging operation is repeated by resetting the magnetic flux of the iron core of the ignition coil. At this time, as shown by V2 in FIG. 2, an AC voltage is generated in the secondary coil 16 at a frequency of 1/2 of 1 / (2 * C1 * R1), and positive / negative polarity inductive discharge is repeated. Can do.

  At this time, if the ON timings of the switching elements 13 and 14 overlap, a current flows simultaneously in the directions of I1-1 and I1-2, leading to a decrease in the secondary coil output energy. It is desirable to provide a dead time between them.

  In addition, the dead time can be inevitably provided by creating the basic operation pulse by the oscillation circuit 3 and the drive pulse of the switching elements 113 and 14 by the flip-flop 4, and the ON timings of the switching elements 13 and 14 overlap. You can avoid that. In addition, you may comprise the said switching element by IGBT. Further, the control unit 4 may be configured integrally with the ECU, or may be configured on a dedicated IC.

  As mentioned above, although embodiment of this invention was described, embodiment is not specifically limited to the said form. The ignition device can be used for any engine that requires it, and the size can be appropriately enlarged or reduced according to the application.

It is a circuit diagram made into an example of the present invention. 1 shows the waveform at each point in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Battery power supply 2 DC power supply 3 Oscillation circuit 4 Control part C1 Oscillation frequency timing capacitor R1 Oscillation frequency timing resistor 7, 8 Timing resistor 9 Operational amplifier 10 Igniter input 11 Ignatator synchronization switch 12 Input protection resistor 13, 14 Primary coil drive Switching element 15 Primary coil 16 Secondary coil 17 Spark plug

Claims (3)

  In an ignition device having a DC power supply as a power source and an ignition coil composed of a primary coil and a secondary coil, and having a primary coil driving switching element on the primary side of the ignition coil, the primary coil driving The switching elements are turned on and off by the control unit to form a push-pull circuit, and the push-pull circuit turns the plurality of switching elements on and off at a single ignition timing. A multiple discharge ignition device characterized in that ignition is performed a plurality of times.   A DC power supply is used as a power source, and an ignition coil including a primary coil and a secondary coil is provided. The primary coil is formed of a center tap type coil, and two or more switching elements are provided at both ends of the primary coil. Connected, the switching element is controlled to be turned on / off by the control unit to form a push-pull circuit, and the plurality of switching elements are turned on / off at one ignition timing by the push-pull circuit to alternately ignite a plurality of times. A multi-discharge ignition device characterized in that it performs.   The secondary coil is electromagnetically coupled to the primary coil to supply a high voltage to the spark plug, and an IGBT is disposed as a switching element in the current path of the primary coil. 2. A multi-ignition ignition device according to 2.

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