JP2006342697A - Ignition system for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ion-current detection device for an internal combustion engine which is used for precisely detecting minute ion current generated within a combustion chamber, which is insensitive to current fluctuations and is stable, and which has a high degree of reliability. <P>SOLUTION: The ignition coil of the ion-current detection device for the internal combustion engine is arranged so that the direction of a power line of an alternator and the winding direction of coil winding comprising the ignition coil cross each other. Alternatively, a shielding member for performing electrostatic shielding of the ignition coil exposed on the top surface of an engine head cover is attached to the engine head cover. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an ion current detection device for an internal combustion engine, and more particularly to an ion current detection device for accurately detecting a minute ion current generated in a combustion chamber.

  FIG. 7 is a diagram showing an output relationship of an ion detection circuit generated by a large current fluctuation in a conventional ignition coil, and FIG. 8 is a diagram of a conventional ignition device for an internal combustion engine. 7 to 8, conventionally, in an ionic current detection device for an internal combustion engine, a combustion state is determined by detecting an ionic current generated after combustion in a combustion chamber, and the operation state of the internal combustion engine is determined based on the combustion state. Techniques have been proposed for grasping or performing various controls such as knocking, lean combustion, and misfire detection according to the grasped combustion state. That is, the ionic current generated in the combustion chamber flows from the spark plug 20 to the ECU (not shown) via the ignition coil 10, and performs various controls such as knocking, lean combustion, and misfire detection by analyzing the ionic current. is there.

  The ion current detection device for an internal combustion engine ignites a spark plug 20 having a spark plug gap 21 disposed in a combustion chamber, the ignition coil 10 that supplies combustion energy to the spark plug 20, and the spark plug gap 21. An ionic current detection device for an internal combustion engine includes an ECU (not shown) for controlling the ignition timing, an igniter 15 of the ignition coil 10, and an ionic current detection means 40 provided between a secondary coil 13 of the ignition coil 10 to be described later. Is configured.

  The ignition coil 10 includes a closed magnetic circuit core 14 and a primary coil 12 in which a primary copper wire is wound around a primary bobbin on the outer periphery of the iron core, and 2 secondary copper wires are provided on the outer periphery of the primary coil. A secondary coil 13 wound around a next bobbin is provided, and a resin-made case 11 that houses the closed magnetic circuit core 14 and each coil is provided. The case 11 receives a primary terminal 16 that receives power from a battery. In some cases, a switching igniter portion (not shown) such as a power transistor that performs ignition control is accommodated, and is molded with a potting resin or the like for insulating and fixing the interior, and as a high voltage output of the ignition device A secondary output unit 18 is provided. The secondary output unit is connected to an ignition plug arranged in the internal combustion engine, and the high voltage obtained from the ignition device configured as described above is applied to the ignition plug, thereby realizing ignition of the internal combustion engine. ing.

  During the ignition operation, when the driver IC 30 receives an ignition signal from an ECU (not shown) that controls the ignition timing, the battery voltage 12V of the automobile is energized to the primary coil 12, and the magnetic energy generated in the primary coil 12 is A magnetic path is propagated from the central iron core 15, and a high voltage corresponding to the turn ratio of the primary coil 12 and the secondary coil 13 is generated in the secondary coil 13. The generated high voltage passes from the secondary coil 13 through the secondary high voltage terminal 18 and is sent to the spark plug 20 that is electrically connected as energy necessary for ignition in the combustion chamber.

Further, at the ignition timing, after the gasoline mixture is burned in the combustion chamber, the ionic current is generated and flows from the spark plug 20 to the ECU (not shown) via the ignition coil 10, and the ionic current acquired by the ionic current detection means 40. By analyzing the above, various controls such as knocking, lean combustion, and misfire detection are performed.
Japanese Patent Laid-Open No. 04-194367

  In the ionic current detection device for an internal combustion engine having such a configuration, the ionic current obtained by combustion of the internal combustion engine has a very small current value such as several μA level. In general, such a small ionic current is amplified. The combustion state is detected. However, when the alternator power line that electrically connects the battery and the alternator that generates electric power from the engine rotation is close to the ignition coil, the electrical noise generated from the alternator power line has an adverse effect on the ignition coil operation and ion current detection. There is a case.

  Specifically, the current supplied from the alternator to the battery has a certain amplitude in the output current due to the structure of the alternator, and appears as a current fluctuation with a maximum amplitude of 20 to 30 A. When such a large current fluctuation appears, a magnetic field corresponding to the current fluctuation generates a strong electric field around the current path according to Ampere's right-hand screw law. The ignition coil is excited by the change in the magnetic field generated by the fluctuation of the large current path, and the output waveform similar to that at the time of ion current appears in the ion detection circuit, and the reliability of the ion current detectability is lost. was there.

  In other words, in the ignition coil 10 of the internal combustion engine ion current detection device that detects the combustion state arranged in the vicinity of the alternator power line 50, the ignition coil 10 passes through the primary coil 12 regardless of the ion current generated by the combustion. Thus, an output waveform synchronized with the current fluctuation of the alternator appears on the secondary coil 13. In particular, when the ignition coil and the alternator power line 50 are close to each other, the ignition coil 10 is electromagnetically induced by a strong electric field, which affects the ion current and impairs reliability. In particular, when the ignition coil 10 is arranged so that the direction of the alternator power line 50 and the winding direction of the coil winding constituting the ignition coil 10 are close to each other and parallel to each other, a problem appears. It was.

  In view of the above problems, an object of the present invention is to provide a stable and highly reliable ion current detection device for an internal combustion engine that is not affected by current fluctuation.

In order to solve the above-mentioned problem, the present inventor examined the cause and found that the alternator was passed through a stray capacitance Cf (see FIG. 9) between the winding of the ignition coil 10 and the alternator power line 50. Ascertaining that the power line 50 is electrostatically coupled to the secondary coil 13 side of the ignition coil 10, the present invention has been completed.
That is, claim 1 of the ignition device for an internal combustion engine of the present invention generates electric power from an engine head cover, an ignition coil mounted on the engine head cover and electrically connected to an ignition plug in a plug hole, and engine rotation. And an alternator power line that electrically connects the batteries is disposed in the vicinity of the ignition coil, the alternator power line direction and the winding direction of the coil winding constituting the ignition coil are The internal combustion engine ignition device is characterized in that the ignition coils are arranged so as to be perpendicular to each other.

  According to a second aspect of the present invention, the engine head cover, an ignition coil that is mounted on the engine head cover and is electrically connected to the spark plug in the plug hole, an alternator that generates electric power from engine rotation, and the battery are electrically connected. In the internal combustion engine in which an alternator power line is disposed in the vicinity of the ignition coil, the ignition coil is arranged so that a direction of the alternator power line and a winding direction of a coil winding constituting the ignition coil are parallel to each other. The internal combustion engine ignition device is characterized in that the engine head cover is provided with a shield material that is arranged and electrostatically shields the ignition coil exposed on the upper surface of the engine head cover.

  A third aspect of the present invention is the internal combustion engine ignition device according to the second aspect, wherein the shield material is a lid-like conductor that covers the ignition coil.

  A fourth aspect of the present invention is the internal combustion engine ignition apparatus according to the second aspect, wherein the shield material is a box-shaped conductor that electrostatically shields an ignition coil disposed in the vicinity of the alternator power line.

  A fifth aspect of the present invention is the internal combustion engine ignition device according to any one of the first to fourth aspects, wherein the ignition coil has an iron core, and the iron core is a closed magnetic circuit iron core.

  A sixth aspect of the present invention provides the internal combustion engine ignition device according to any one of the first to fifth aspects, wherein the iron core covers the upper and lower surfaces of the iron core uniformly with a conductor.

  A seventh aspect of the present invention is the internal combustion engine ignition device according to the sixth aspect, wherein the conductor is an aluminum tape.

  According to an eighth aspect of the present invention, the alternator power line is a stacking height direction of a thin plate constituting a central iron core among a closed magnetic circuit iron core penetrating a central axis of the primary coil and the secondary coil constituting the ignition coil. On the other hand, the internal combustion engine ignition device according to any one of claims 2 to 7, wherein the internal combustion engine ignition device is wired at the same position as the central iron core. The present invention preferably exhibits a synergistic effect by appropriately combining the above means. Therefore, the present invention is also an ignition coil according to any one of claims 1 to 6 combined.

  By adopting the structure of the internal combustion engine ignition coil 10 described above, a stable and reliable ion current detection device for an internal combustion engine that is not affected by the position of the alternator power line is obtained in the ion current detection device for the internal combustion engine. It is done.

  Hereinafter, the present invention will be described based on examples. FIG. 1 is a diagram in which ignition coils are arranged such that the alternator power line direction according to the first embodiment and the winding direction of the coil winding constituting the ignition coil are perpendicular to each other. FIG. 2 is a diagram of an ignition coil installed in the engine head cover according to the second embodiment and a shield cover that completely covers the ignition coil. FIG. 3 is a diagram of an ignition coil installed in the engine head cover according to the third embodiment and a shield box that completely covers the ignition coil. FIG. 4 is an ignition coil diagram constituted by an E-type iron core having a closed magnetic circuit according to the fourth embodiment. FIG. 5 is an ignition coil diagram in which the iron core according to the fifth embodiment is covered with a conductor. FIG. 6 is a diagram in which the alternator power line according to the sixth embodiment is located at the same position as the center iron core of the ignition coil. An ignition device for an internal combustion engine of the present invention includes an engine head cover, an ignition coil that is mounted on the engine head cover and electrically connected to an ignition plug in a plug hole, an alternator that generates electric power from engine rotation, and a battery The alternator power line is electrically connected to each other, and the alternator power line is disposed in the vicinity of the ignition coil.

  1 to 6, the ignition coil configuration of the embodiment is the same as that of the conventional ignition coil, and is a closed magnetic circuit core 14 and a primary coil in which a primary copper wire is wound around a primary bobbin around the iron core. 12, a secondary coil 13 in which a secondary copper wire is wound around a secondary bobbin around the outer periphery of the primary coil, and a resin case 11 that houses the closed magnetic circuit core 14 and each coil. The case 11 accommodates a primary terminal 16 that is supplied with power from a battery, and a switching igniter portion (not shown) such as a power transistor that performs ignition control in some cases, and a potting resin for insulating and fixing the interior. The secondary output unit 18 is provided as a high voltage output of the ignition device. The secondary output unit 18 is connected to a spark plug 20 disposed in the internal combustion engine, and the high voltage obtained from the ignition device configured as described above is applied to the spark plug, thereby igniting the internal combustion engine. Realized.

  In the first embodiment, as shown in FIG. 1, the ignition device for an internal combustion engine is configured so that the direction of the alternator power line 50 and the winding direction of the coil winding constituting the ignition coil 10 are perpendicular to each other. Place. At this time, it has been found that the current is not affected by the current fluctuation of the alternator power line 50. As a result, even when the ignition coil 10 is arranged in the vicinity of the alternator power line 50, the ion waveform can be detected satisfactorily without generating an output waveform synchronized with the current fluctuation of the alternator unrelated to the ion current. Can do.

  In the second embodiment, as shown in FIG. 2, the internal combustion engine ignition device is installed in the upper surface recess A of the engine head cover 3 and exposed to the upper surface from the engine head cover 3 when the engine head cover is made of aluminum. The ignition coil 10 can be completely covered by the shield cover 121 that is a lid-like conductor. Since the shield cover 121 is made of a conductor, it can be completely electrostatically shielded by completely covering the ignition coil 10 from the outside. As a result, even when the ignition coil 10 is disposed in the vicinity of the alternator, it is possible to detect the ion current satisfactorily without generating an output waveform synchronized with the current fluctuation of the alternator unrelated to the ion current. .

  Further, in Example 3, as shown in FIG. 3, when the engine head cover is made of a resin material, the internal combustion engine ignition device is installed in the upper surface recess A of the engine head cover 3 and is exposed to the upper surface from the engine head cover 3. The ignition coil 10 can completely cover each ignition coil 10 by the shield box 122 which is a box-shaped conductor. Since the shield box 122 is made of a conductor, it can be electrostatically shielded from the outside by covering the ignition coil 10. As a result, even when the ignition coil 10 is disposed in the vicinity of the alternator, it is possible to detect the ion current satisfactorily without generating an output waveform synchronized with the current fluctuation of the alternator unrelated to the ion current. .

  In the fourth embodiment, as shown in FIG. 4, when the ignition coil 10 of the ignition device for an internal combustion engine is configured by an E-type iron core 114 having a closed magnetic circuit, it is not affected by the current fluctuation of the alternator power line 50. I discovered that. As a result, even when the ignition coil 10 is disposed in the vicinity of the alternator, it is possible to detect the ion current satisfactorily without generating an output waveform synchronized with the current fluctuation of the alternator unrelated to the ion current. .

  In Example 5, as shown in FIG. 5, the ignition coil 10 and the iron core 14 of the ignition device for an internal combustion engine are covered with a conductor 120. The conductor 120 may be a thin aluminum tape, a coating material containing a conductor, or any conductor that can uniformly cover the upper and lower surfaces of the iron core 14. As a result, even when the ignition coil 10 is disposed in the vicinity of the alternator, it is possible to detect the ion current satisfactorily without generating an output waveform synchronized with the current fluctuation of the alternator unrelated to the ion current. .

Further, in the sixth embodiment, as shown in FIG. 6, the ignition coil 10 of the internal combustion engine ignition device includes the alternator power line 50, which is a central axis of the primary coil 12 and the secondary coil 13 constituting the ignition coil 10. When wiring is performed at the same position as the central iron core with respect to the stacking height direction of the thin plates constituting the central iron core of the closed magnetic circuit iron core 14 penetrating the core, the influence of the current fluctuation of the alternator power line 50 is affected. I found that I did not receive it. As a result, even when the ignition coil 10 is arranged in the vicinity of the alternator, the output waveform synchronized with the current fluctuation of the alternator irrelevant to the ion current does not appear and the ion current is detected well. be able to.
Although the embodiments of the present invention have been specifically described above, the above description is merely an example, and can be appropriately changed without departing from the spirit of the present invention.

It is the figure which has arrange | positioned the ignition coil so that the alternator electric power line direction which concerns on Example 1 and the winding direction of the coil winding which comprises an ignition coil become a mutually orthogonal direction. It is a figure of the ignition cover installed in the engine head cover which concerns on Example 2, and the shield cover which completely covers an ignition coil. It is a figure of the ignition box installed in the engine head cover which concerns on Example 3, and the shield box which completely covers an ignition coil. It is the ignition coil figure comprised with the E-type iron core of the closed magnetic circuit which concerns on Example 4. FIG. It is the ignition coil figure by which the iron core which concerns on Example 5 was covered with the electrically conductive material. It is a figure in which the alternator electric power line which concerns on Example 6 exists in the same position as the center part iron core of an ignition coil. It is a figure which shows the output relationship of the ion detection circuit by the heavy current fluctuation | variation in the conventional ignition coil. It is a figure of the conventional ignition device for internal combustion engines. It is a circuit diagram of the conventional ignition device for internal combustion engines.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Internal combustion engine ignition device 2 Internal current engine ion current detection device 3 Engine head cover 10 Ignition coil 11 Case 12 Primary coil 13 Secondary coil 14 Closed magnetic circuit iron core 15 Core iron core 16 Primary terminal 18 Secondary output part 20 Ignition Plug 30 driver IC
40 Ion current detection means 50 Alternator power line 114 E-type iron core 120 Conductor 121 Shield cover 122 Shield box

Claims (8)

  An engine head cover, an ignition coil that is mounted on the engine head cover and electrically connected to the spark plug in the plug hole, an alternator that generates electric power from engine rotation, and an alternator power line that electrically connects the batteries In the internal combustion engine disposed in the vicinity of the ignition coil, the ignition coil is disposed such that the alternator power line direction and the winding direction of the coil winding constituting the ignition coil are perpendicular to each other. An internal combustion engine ignition device.   An engine head cover, an ignition coil that is mounted on the engine head cover and electrically connected to the spark plug in the plug hole, an alternator that generates electric power from engine rotation, and an alternator power line that electrically connects the batteries In the internal combustion engine engine arranged in the vicinity of the ignition coil, the ignition coil is arranged such that the alternator power line direction and the winding direction of the coil winding constituting the ignition coil are parallel to each other, and the engine An internal combustion engine ignition device characterized in that a shield material that electrostatically shields the ignition coil exposed on the upper surface of the head cover is attached to the engine head cover.   The internal combustion engine ignition device according to claim 2, wherein the shield material is a lid-like conductor that covers the ignition coil.   The internal combustion engine ignition device according to claim 2, wherein the shield material is a box-shaped conductor that electrostatically shields an ignition coil disposed in the vicinity of the alternator power line.   5. The internal combustion engine ignition device according to claim 1, wherein the ignition coil has an iron core, and the iron core is a closed magnetic circuit iron core.   6. The internal combustion engine ignition device according to claim 1, wherein the iron core covers the upper and lower surfaces of the iron core uniformly with a conductor.   The internal combustion engine ignition device according to claim 6, wherein the conductor is aluminum tape.   The alternator power line is centered with respect to the stacking height direction of the thin plates constituting the central iron core among the closed magnetic circuit iron cores passing through the central axis of the primary coil and the secondary coil constituting the ignition coil. 8. The internal combustion engine ignition device according to claim 2, wherein the internal combustion engine ignition device is wired at the same position as the iron core.

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