JP2008166580A - Ignition coil for multiple ignition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ignition structure having optimum ignition conditions and control thereof in a combustion engine of a multiple ignition system. <P>SOLUTION: The ignition coil for multiple ignition has a structure in which a closed magnetic circuit is constituted by a center core formed by laminating silicon steel thin plates and an outer circumferential core formed by laminating silicon steel thin plates, a primary coil formed by coaxially winding a primary copper wire and a secondary core formed by winding a secondary copper wire are disposed on the center core, the primary coil and the secondary coil are housed in a case, and a magnet is attached on an air gap provided between a center iron core and an outer circumferential iron core in the combustion engine ignition coil injection-molded with an insulating resin. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an ignition coil for an internal combustion engine, and more particularly to a multi-ignition ignition coil that performs an ignition operation a plurality of times in one explosion stroke.

  In the control of an ignition coil for multi-ignition for an internal combustion engine, as disclosed in Japanese Patent Laid-Open No. 2000-345949 (Patent Document 1) or Japanese Patent Laid-Open No. 2000-314341 (Patent Document 2), it is performed once. Proposals have been made for ignition control means for performing multiple ignitions in the explosion stroke. In particular, Patent Document 1 proposes a technique for controlling the ignition timing in accordance with the battery voltage.

JP 2000-345949 A JP 2000-314341 A

  However, in the multi-ignition ignition coil that has been proposed in the past, there is no proposal for the total ignition time or ignition timing, ignition conditions, etc. of ignition in one explosion stroke, and continuous ignition under any conditions is optimal It has not been verified.

  The present invention has been made in view of such a problem, and an object of the present invention is to propose a structure and control of an ignition coil that provides optimum ignition conditions in a multi-ignition internal combustion engine.

  In order to solve the above problems, the present invention is configured as follows. That is, in claim 1, a closed magnetic path is constituted by a central core formed by stacking silicon steel thin plates and an outer peripheral core formed by stacking silicon steel thin plates, and is coaxial with the central core. A primary coil wound with a primary copper wire and a secondary coil wound with a secondary copper wire are arranged in the case. These primary coil and secondary coil are housed in a case and cast with an insulating resin. A multi-ignition ignition coil in which a magnet is attached to an air gap provided between a central iron core and an outer peripheral iron core.

  According to a second aspect of the present invention, a reverse bias having a BH characteristic is obtained by the magnet so that a rise time in the initial energization of the primary coil is shortened. In the third aspect, a single explosion stroke is performed. The primary charge time in the second and subsequent charging / discharging cycles is set to 100 μs to 200 μs. 2. The ignition coil for multi-ignition according to claim 1, wherein the secondary discharge time in the second and subsequent charge / discharge cycles in one explosion stroke is set to 50 [mu] s to 200 [mu] s.

  In addition, when single charge / discharge is performed in one explosion stroke, the discharge energy of the ignition coil is set to 35 mJ or more, and the core may be formed of powdered material. Alternatively, the primary resistance may be 50 to 300 mΩ, the cross-sectional area of the central core portion may be 100 square millimeters or less, and the number of turns of the primary coil may be 50 to 100 turns, and the turn ratio of the primary coil and the secondary coil may be 100 to 200. Good.

  In the ignition coil using a non-directional silicon steel plate as a core for forming a closed magnetic circuit with a driving current of the ignition coil of 10 to 20 A, the reverse magnetic bias of the magnet is 1.2 to 1.6 T, and the directional silicon In the ignition coil using a steel plate, the reverse magnetic bias of the magnet may be 1.6 to 2.0 T, the charging time tL is 500 μS or less, the charging time tNL is 150 μS or less, and the ignition timing tFP is 50 during multi-ignition. By setting to 100 μS, a more efficient multi-ignition ignition coil can be provided. With the above configuration, even an ignition coil that performs multi-ignition can reliably obtain sufficient ignition energy, and can solve problems such as misfire and ignition mistake due to insufficient energy.

  Next, examples of the present invention will be described. In the present invention, as a feature of the ignition coil structure, as shown in FIG. 1, a closed magnetic path core is formed from a plurality of laminated cores 10 and 12, and at least one gap among the gaps generated on the combination surface of the respective laminated cores is formed. A magnet 20 made of a permanent magnet is disposed. The magnet 20 is arranged in a portion where the core is obliquely cut as shown in FIGS. 1A and 1C to form an oblique gap, or one end of the central core is enlarged as shown in FIG. Thus, the magnetic bias can be sufficiently applied by making the cross-sectional area large. The magnetic bias preferably has a reverse bias up to the third positive element saturation region of the BH characteristic.

  A circuit configuration relating to the ignition coil of the present invention will be described. FIG. 2 is a circuit diagram of an ignition coil for multi-ignition according to the present invention, where B is a power source obtained from a vehicle battery, and the power source B is connected to the primary coil 51 and the primary coil transistor, etc. Is connected to an ignition control unit 53 including a switching element, and the ignition coil is provided with a secondary coil 52 via a core, and at least one end of the secondary coil 52 is formed by a spark plug. A secondary high voltage is generated in response to a signal from the ignition control unit 53, connected to the gap 54, and the fuel is ignited by discharging the gap 54.

  The operation at the time of multi-ignition will be specifically described below. FIG. 3 shows a primary current rising characteristic diagram of an ignition coil using three types of core structures having different characteristics. In FIG. 3, A is an ignition coil having an energy of 15A and a magnet arranged at 50 mJ at the core, B is the same 40 mJ without magnet, C is the same 30 mJ without magnet, and shows an example of the primary current rising characteristic. Yes. In FIG. 3, the characteristic of A indicates that the rising characteristic is excellent from 0 to 0.2 mS (200 μS) with respect to B and C without magnet. It shows that the rise of C is better than A after 0.2 mS, and the rise of B is better than A after 0.4 mS.

  FIG. 4 shows an output waveform of secondary energy when performing multi-ignition. In FIG. 4, tL is a charging time, tFP is an ignition timing interval time which is a charging time between a plurality of ignitions / ignitions in one explosion stroke, and tNL is a plurality of ignitions in one explosion stroke. Of these, the ignition time is one time, and tD indicates the time when tNL and tFP are combined. In the present invention, by setting each of the above times as follows, it is possible to obtain sufficient ignition energy when performing multi-ignition and to obtain an optimal ignition coil free from ignition mistakes. That is, in the present invention, a more efficient multi-ignition ignition coil can be obtained by setting the charging time tL to 500 μS or less, the charging time tNL to 150 μS or less, and the ignition timing tFP from 50 to 100 μS during multi-ignition. This has been confirmed experimentally as shown in FIG.

  As another condition, the primary resistance is 50 to 300 mΩ, the cross-sectional area of the central core is 100 square millimeters or less, the number of turns of the primary coil is 50 to 100 turns, and the turns ratio of the primary coil and the secondary coil is 100 to 200, and the driving current of the ignition coil is 10 to 20A. Further, in an ignition coil using a non-oriented silicon steel plate as a core forming a closed magnetic path, the reverse magnetic bias of the magnet is 1.2 to 1.6 T, and when using a directional silicon steel plate, the reverse magnetic bias is 1 It has also been confirmed that it is optimal to set to .6 to 2.0T. Note that the recent power supply voltage (= battery voltage) is about 14V and 42V, but the power supply voltage in the above embodiment is particularly suitable for a 14V system.

It is a structural view showing the relationship between the core and the magnet of the present invention. It is an example of the schematic circuit diagram of the ignition coil used for this invention. The primary current rising characteristic figure of each ignition coil which changes with the presence or absence of a core is shown. The secondary output waveform at the time of multi ignition is shown.

Explanation of symbols

10, 12 Laminated core 20 Magnet 51 Primary coil 52 Secondary coil 53 Ignition controller 54 Plug gap

Claims (11)

A central magnetic core formed by laminating silicon steel thin plates and an outer core formed by laminating silicon steel thin plates constitute a closed magnetic circuit, and a primary copper wire is wound around the central core coaxially. A primary coil and a secondary coil wound with a secondary copper wire are arranged. The primary coil and the secondary coil are housed in a case and are centered on an ignition coil for an internal combustion engine casted with an insulating resin. Multi-ignition ignition coil with a magnet installed in the air gap between the iron core and the outer core.   The ignition coil for multi-ignition according to claim 1, wherein a reverse bias having a BH characteristic is obtained by the magnet, and a rise time at the initial energization of the primary coil is shortened.   The ignition coil for multi-ignition according to claim 1, wherein the primary charge time in the second and subsequent charge / discharge cycles in one explosion stroke is set to 100 µs to 200 µs.   The ignition coil for multi-ignition according to claim 1, wherein the secondary discharge time in the second and subsequent charge / discharge cycles in one explosion stroke is set to 50 µs to 200 µs.   2. The ignition coil for multi-ignition according to claim 1, wherein the discharge energy of the ignition coil is set to 35 mJ or more when single discharge is performed in one explosion stroke.   The ignition coil for multi-ignition according to any one of claims 1 to 5, wherein the core is made of a powdered material.   The primary resistance is 50 to 300 mΩ, the cross-sectional area of the central core is 100 square millimeters or less, the number of turns of the primary coil is 50 to 100 turns, and the turn ratio of the primary coil and the secondary coil is 100 to 200. The ignition coil for multi-ignition according to claim 1, wherein the ignition coil is multi-ignition.   2. The ignition coil for multi-ignition according to claim 1, wherein the drive current of the ignition coil is 10 to 20A.   2. The ignition coil for multi-ignition according to claim 1, wherein a reverse magnetic bias of the magnet is 1.2 to 1.6 T in an ignition coil using a non-oriented silicon steel plate as a core forming a closed magnetic path. .   2. The ignition coil for multi-ignition according to claim 1, wherein a reverse magnetic bias of the magnet is set to 1.6 to 2.0 T in an ignition coil using a directional silicon steel plate for a core forming a closed magnetic path.   2. The ignition coil for multi ignition according to claim 1, wherein the charging time tL is set to 500 μS or less, the charging time tNL is set to 150 μS or less, and the ignition timing tFP is set to 50 to 100 μS at the time of multi ignition.

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