JP2008248779A

JP2008248779A - Igniter for internal combustion engine

Info

Publication number: JP2008248779A
Application number: JP2007090672A
Authority: JP
Inventors: Gonosuke Inamura; 豪乃助稲村; Yasuhiro Inoue; 泰宏井上
Original assignee: Diamond Electric Manufacturing Co Ltd
Current assignee: Diamond Electric Manufacturing Co Ltd
Priority date: 2007-03-30
Filing date: 2007-03-30
Publication date: 2008-10-16

Abstract

<P>PROBLEM TO BE SOLVED: To provide an igniter for an internal combustion engine having an ion current detection function and capable of realizing the high voltage of the ion current detection power supply voltage for improving the S/N ratio when detecting the ion current without degrading the output performance of an ignition coil while preventing any lead angle (premature ignition) of the ignition timing of the internal combustion engine. <P>SOLUTION: The igniter for the internal combustion engine comprises a primary coil in which the primary current is subjected to the ON-OFF control by an electronically-controlled primary current breaking device, a secondary coil which is electromagnetically coupled with the primary coil to supply the high voltage to an ignition plug 2, and a means which is provided with a power supply circuit 6 for detecting the ion current and an ion current amplification circuit 7 on the secondary coil low-voltage side to switch a secondary coil output current path by the self-contained control not requiring any signal input from the outside. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

本発明は、内燃機関用点火装置に関し、特に点火コイルの出力エネルギ損失の低減手段をもつ内燃機関用イオン電流検出装置に関する。 The present invention relates to an ignition device for an internal combustion engine, and more particularly to an ion current detection device for an internal combustion engine having means for reducing output energy loss of an ignition coil.

自動車エンジンなどの内燃機関において、図６に開示されたイオン電流検出をもつ内燃機関用点火装置がある。図６において、１はバッテリー電源、２は点火プラグ、３は点火コイル、３１は１次コイル、３２は２次コイル、４は制御回路、５は１次電流遮断素子、６はイオン電流検出用電源回路、７はイオン電流増幅回路である。イオン電流検出用電源回路において、６１はイオン電流検出電源電圧作成用ＺＤ、６２はイオン電流検出電源用コンデンサ、６３は２次放電電流経路用ダイオード、６４はイオン電流検出用抵抗である。イオン電流増幅回路において、７１は入力保護ダイオード、７２はイオン電流増幅回路である。 In an internal combustion engine such as an automobile engine, there is an ignition device for an internal combustion engine having ion current detection disclosed in FIG. In FIG. 6, 1 is a battery power source, 2 is an ignition plug, 3 is an ignition coil, 31 is a primary coil, 32 is a secondary coil, 4 is a control circuit, 5 is a primary current interruption element, and 6 is an ion current detection element. A power supply circuit 7 is an ion current amplification circuit. In the ion current detection power supply circuit, 61 is an ion current detection power supply voltage creation ZD, 62 is an ion current detection power supply capacitor, 63 is a secondary discharge current path diode, and 64 is an ion current detection resistor. In the ion current amplifier circuit, 71 is an input protection diode, and 72 is an ion current amplifier circuit.

図６に開示されたイオン電流検出をもつ内燃機関用点火装置の動作波形を図７に示す。点火信号ａのHighレベルが入力されると、１次コイル３１に電流ｂが通電開始され２次コイルに高電圧が誘導される。この時に発生する高電圧は２次コイルの低圧側がイオン電流検出用電源電圧ｅでバイアスされているため、前記高電圧はイオン電流検出用電源電圧ｅに重畳される。この時に発生する高電圧の自由振動によって、イオン電流検出電源用コンデンサが充放電されるためイオン電流増幅回路は自由振動に応じた電圧波形を出力する。点火信号ａがＬｏｗレベルに切り替わると、１次コイル電流ｂが遮断され１次コイルに発生する逆起電圧の２次コイル巻数／１次コイル巻数倍の高電圧が２次コイル３２に誘導される。この高電圧がプラグギャップ間の絶縁破壊電圧を超えるとプラグギャップ間放電が開始され、内燃機関のシリンダー内壁からプラグギャップのＧＮＤ−電極間放電を経て２次コイル、２次コイル低圧側に接続されるＺＤをブレークさせて２次コイル放電電流経路用ダイオード６３を経てＧＮＤに至るループで２次コイル電流ｄが、通電される。２次コイル電流によってブレークダウンするイオン電流検出電源電圧作成用ＺＤ６１のブレークダウン電圧によってイオン電流検出電源用コンデンサ６２が充電され、プラグギャップ間放電が終了し残留エネルギによる２次コイルの自由振動が収束した後、プラグギャップ間に燃焼による火炎を通してイオン電流検出電源用コンデンサ６２は放電を開始し、放電電流波形をイオン電流増幅回路がイオン電流波形として電圧波形を出力する。 FIG. 7 shows operating waveforms of the internal combustion engine ignition device having the ion current detection disclosed in FIG. When the high level of the ignition signal a is input, the current b starts to be supplied to the primary coil 31 and a high voltage is induced in the secondary coil. Since the low voltage side of the secondary coil is biased with the ion current detection power supply voltage e, the high voltage generated at this time is superimposed on the ion current detection power supply voltage e. Since the ion current detection power supply capacitor is charged and discharged by the high voltage free vibration generated at this time, the ion current amplification circuit outputs a voltage waveform corresponding to the free vibration. When the ignition signal a is switched to the low level, the primary coil current b is cut off, and a high voltage that is the number of secondary coil turns / times the number of primary coil turns of the counter electromotive voltage generated in the primary coil is induced in the secondary coil 32. The When this high voltage exceeds the dielectric breakdown voltage between the plug gaps, the discharge between the plug gaps is started, and is connected from the inner wall of the internal combustion engine cylinder to the secondary coil and secondary coil low voltage side via the GND-electrode discharge of the plug gap. The secondary coil current d is energized in a loop that breaks the ZD and reaches the GND through the secondary coil discharge current path diode 63. The ion current detecting power source capacitor 62 is charged by the breakdown voltage of the ion current detecting power source voltage generating ZD 61 that breaks down by the secondary coil current, the plug gap discharge is completed, and the free vibration of the secondary coil due to the residual energy converges. After that, the ion current detection power supply capacitor 62 starts discharging through a flame due to combustion between the plug gaps, and the ion current amplification circuit outputs a voltage waveform with the discharge current waveform as the ion current waveform.

ここで点火コイルの出力特性上問題となるのが２次放電電流経路中に存在するＺＤ６１である。プラグギャップ間放電中、すなわち２次コイルのエネルギ出力期間の全期間においてＺＤ６１はブレークダウンの状態でありＺＤ６１において、Ｅｄ＝｛（２次放電電流（Ｉ２）×ＺＤ６１ブレークダウン電圧（Ｖｚ））／２｝×プラグギャップ間放電時間（Ｔ２）の損失が発生する。この為、２次コイル出力エネルギＥ２は、点火に使用できるエネルギからＺＤ６１で発生する損失Ｅｄが差し引かれ、Ｅ２−Ｅｄのエネルギしか利用できない。 Here, ZD61 existing in the secondary discharge current path is a problem in the output characteristics of the ignition coil. During discharge between plug gaps, that is, during the entire energy output period of the secondary coil, ZD61 is in a breakdown state, and in ZD61, Ed = {(secondary discharge current (I2) × ZD61 breakdown voltage (Vz)) / 2} × Plug gap discharge time (T2) loss occurs. For this reason, as the secondary coil output energy E2, the loss Ed generated in the ZD 61 is subtracted from the energy that can be used for ignition, and only the energy of E2-Ed can be used.

点火に利用できるエネルギは、ＺＤ６１のブレークダウン電圧に反比例の関係で低下していくが、イオン電流検出において検出するイオン電流はｕＡオーダの微少電流で、検出回路に重畳されるノイズとの分離は大きな問題であり、イオン電流検出装置の耐ノイズ性の向上にはイオン電流検出時におけるプラグギャップ間印加電圧を高電圧化し、検出対象であるイオン電流を高電流化することによるＳ／Ｎ比の向上が効果的である。しかし、イオン電流検出時におけるプラグギャップ間印加電圧を高電圧化することは、図６におけるＺＤ６１の高電圧化を意味し図７に示す特性の様に点火に利用できるエネルギが低下してしまう。イオン電流検出性の向上と点火性能の向上は相反する特性であり、両者の特性を同時に向上させるためには、あらかじめＺＤ６１で損失するエネルギを見越した点火コイル設計が必要であり、イオン電流検出性を向上すればするほどＺＤ６１での損失を賄う為の余剰エネルギを必要とし、効率的な点火コイル設計ができない。 The energy available for ignition decreases in inverse proportion to the breakdown voltage of ZD61, but the ion current detected in the ion current detection is a minute current on the order of uA, and is separated from the noise superimposed on the detection circuit. It is a big problem, and the noise resistance of the ion current detector is improved by increasing the applied voltage between the plug gaps at the time of detecting the ion current and increasing the S / N ratio by increasing the ion current to be detected. Improvement is effective. However, increasing the applied voltage between the plug gaps at the time of detecting the ionic current means increasing the voltage of the ZD 61 in FIG. 6, and the energy available for ignition is reduced as in the characteristics shown in FIG. Improvement in ion current detection and improvement in ignition performance are contradictory characteristics. To improve both characteristics at the same time, it is necessary to design an ignition coil in anticipation of energy lost in ZD61 in advance. The more it is improved, the more energy is required to cover the loss in ZD61, and the more efficient ignition coil design cannot be made.

また、イオン電流検出機能をもつ内燃機関用点火装置において、２次コイル低圧側はイオン電流検出用電源回路によってプラグギャップ間印加電圧（Ｖｉｏｎ）でバイアスされていることから１次電流通電開始時に２次コイルに１次コイルと２次コイルの相互誘導によって誘起される高電圧はＶｉｏｎを基準にＶ２ｏｎ＝バッテリ電圧（Ｖ１）×１次／２次コイル巻数比（ｎ１／ｎ２）の電圧が発生し、プラグギャップ間にはＶ２ｏｎ＋Ｖｉｏｎの電圧が印加される。この電圧が高すぎると内燃機関の点火時期の進角（過早点火）を引き起こす原因となる。 Further, in the internal combustion engine ignition device having an ion current detection function, the secondary coil low voltage side is biased by the plug gap applied voltage (Vion) by the ion current detection power supply circuit. The high voltage induced by the mutual induction of the primary coil and the secondary coil in the secondary coil is a voltage of V2on = battery voltage (V1) × primary / secondary coil turns ratio (n1 / n2) based on Vion. A voltage of V2on + Vion is applied between the plug gaps. If this voltage is too high, the ignition timing of the internal combustion engine may be advanced (premature ignition).

イオン電流検出機能をもつ内燃機関において、上述の問題を回避する手段として１次コイルと２次コイルの巻数比を低減する解決策があるが、１次電流通電時に２次コイルに誘導される高電圧はイオン電流検出用電源回路電圧に重畳されるので、イオン電流検出用電源電圧を高電圧化しＳ／Ｎ比を向上しようとすると、内燃機関における点火時期の進角（過早点火）の危険性が増すことになる。 In an internal combustion engine having an ion current detection function, there is a solution for reducing the turns ratio of the primary coil and the secondary coil as means for avoiding the above-mentioned problem. Since the voltage is superimposed on the power supply circuit voltage for ion current detection, if the power supply voltage for ion current detection is increased to improve the S / N ratio, there is a risk of ignition timing advance (pre-ignition) in the internal combustion engine. It will increase the nature.

内燃機関における点火時期の進角（過早点火）を回避するため、前記の解決策を用いると１次コイルと２次コイルの巻数比の低減により点火性能が低下することにより、イオン電流検出用電源電圧の高電圧化には限界が生じＳ／Ｎ比の向上は困難であった。 In order to avoid the advance of ignition timing (premature ignition) in an internal combustion engine, if the above-mentioned solution is used, the ignition performance is reduced due to the reduction in the turn ratio of the primary coil and the secondary coil. There is a limit to increasing the power supply voltage, and it has been difficult to improve the S / N ratio.

本発明は上記の問題点に鑑みてなされたものであって、イオン電流検出におけるＳ／Ｎ比向上のためのイオン電流検出電源電圧の高電圧化を、点火コイルの出力性能を低下させず、且つ内燃機関の点火時期の進角（過早点火）も防いで実現できる、イオン電流検出機能をもつ内燃機関用点火装置を提供することを目的とする。 The present invention has been made in view of the above-described problems, and it is possible to increase the ion current detection power supply voltage for improving the S / N ratio in ion current detection without reducing the output performance of the ignition coil. It is another object of the present invention to provide an ignition device for an internal combustion engine having an ion current detection function that can be realized by preventing the advance timing (premature ignition) of the ignition timing of the internal combustion engine.

上記課題を解決するために本発明においては次のような構成とする。即ち、請求項１においては、電子制御される１次電流遮断素子により１次電流がオンオフ制御される１次コイルと、前記１次コイルに電磁結合されて点火プラグに高電圧を供給する２次コイルと、２次コイル低圧側にイオン電流検出用電源回路とイオン電流増幅回路が配置され外部からの信号入力を必要としない自立制御によって２次コイル出力電流経路を切り替える手段と、イオン電流検出用電源の充電動作による２次コイル出力エネルギの損失を抑制できることを特徴とするイオン電流検出機能をもつ内燃機関用点火装置とする。 In order to solve the above problems, the present invention has the following configuration. That is, in claim 1, a primary coil whose primary current is on / off controlled by an electronically controlled primary current cutoff element, and a secondary that is electromagnetically coupled to the primary coil and supplies a high voltage to the spark plug. An ion current detecting power supply circuit and an ion current amplifying circuit disposed on the low voltage side of the coil, means for switching the secondary coil output current path by self-sustained control that does not require external signal input, and for detecting the ion current An internal combustion engine ignition device having an ion current detection function, characterized in that loss of secondary coil output energy due to a charging operation of a power source can be suppressed.

請求項２においては、１次電流通電開始時に２次コイル出力電流経路の切り替え手段によりイオン電流検出電源の充電電荷を放電し、２次コイル低圧側と基準電位との電位差をほぼ等電位とすることで１次電流通電開始時に２次コイルに発生する高電圧を抑制することができ、前記の２次コイル出力電流経路の切り替え動作とイオン電流検出電源の充電電荷の放電が、１次電流遮断素子の駆動回路に点火信号が入力されてから１次電流遮断素子が通電開始するまでの遅延時間内でなされることを特徴とするイオン電流検出機能をもつ内燃機関用点火装置とする。 According to the second aspect of the present invention, the charging current of the ion current detection power source is discharged by the switching means of the secondary coil output current path at the start of energization of the primary current, and the potential difference between the secondary coil low voltage side and the reference potential is made substantially equal. Therefore, the high voltage generated in the secondary coil at the start of energization of the primary current can be suppressed, and the switching operation of the secondary coil output current path and the discharge of the charged charge of the ion current detection power source are interrupted by the primary current. An ignition apparatus for an internal combustion engine having an ion current detection function, characterized in that it is performed within a delay time from when an ignition signal is input to the drive circuit of the element until the primary current interrupting element starts energization.

上記構成により、イオン電流検出用電源の充電動作による２次コイル出力エネルギの損失を抑制できるイオン電流検出機能をもつ内燃機関用点火装置が提供できる。また、１次電流遮断素子のゲート直列抵抗を上述の範囲で調整し、点火信号による２次コイル電流切り替え素子の通電状態への移行を行うことによって１次電流通電開始時に２次コイルへ誘導される高電圧を抑制し内燃機関の点火時期の進角（過早点火）を防ぐことができる。さらに、本発明は組み合わされる１次及び２次コイルに依存することなく、外部からの独立した制御信号を必要とせずに２次コイル電流経路を切り替えてイオン電流検出用電源回路での点火コイルの出力エネルギ損失を抑制し、１次電流通電開始時に２次コイルに生じる高電圧を抑制することができるイオン電流検出機能付き内燃機関用点火装置を実現できる。 With the above configuration, it is possible to provide an ignition device for an internal combustion engine having an ion current detection function capable of suppressing the loss of secondary coil output energy due to the charging operation of the ion current detection power source. In addition, by adjusting the gate series resistance of the primary current interrupting element in the above range and shifting to the energized state of the secondary coil current switching element by the ignition signal, it is induced to the secondary coil at the start of energizing the primary current. Therefore, it is possible to prevent the advance timing (premature ignition) of the ignition timing of the internal combustion engine. Furthermore, the present invention does not depend on the combined primary and secondary coils, and switches the secondary coil current path without requiring an independent external control signal, so that the ignition coil in the ion current detection power supply circuit can be switched. An ignition device for an internal combustion engine with an ion current detection function that can suppress an output energy loss and suppress a high voltage generated in the secondary coil at the start of energization of the primary current can be realized.

本発明の実施例を示す図１において、１次電流遮断素子５による電子制御によって１次電流がオンオフ制御される１次コイル３１と、前記１次コイルに電磁結合されて点火プラグに高電圧を供給する２次コイル３２を備え、２次コイル３２の低圧側にイオン電流検出用電源回路６を持ち、イオン電流検出用電源回路７と並列に２次コイル出力電流経路切り替え素子８が接続されている。 In FIG. 1 showing an embodiment of the present invention, a primary coil 31 whose primary current is on / off controlled by electronic control by a primary current interrupting element 5 and a high voltage applied to the spark plug by being electromagnetically coupled to the primary coil. A secondary coil 32 to be supplied is provided, the ion current detection power supply circuit 6 is provided on the low voltage side of the secondary coil 32, and the secondary coil output current path switching element 8 is connected in parallel with the ion current detection power supply circuit 7. Yes.

図１におけるイオン電流検出電源用コンデンサ６２に充電される電荷量は２．７ｕＣ〜８ｕＣ程度で、この電荷量の充電に必要なエネルギは、０．１ｍＪ〜１．３２ｍＪ程度であり、コンデンサ６２の充電で失われるエネルギは内燃機関により異なるが３０ｍＪ〜９０ｍＪ必要とされる点火コイルの出力エネルギに対しほとんど影響を及ぼさない。一方ＺＤ６１での損失は、Ｖｚ及びプラグギャップ間放電時間に比例し、図７の様に損失が発生する。つまり、２次コイルのエネルギ出力期間において、コンデンサ６２の充電完了後もＺＤ６１のブレークダウンが継続され２次コイル出力電流経路が形成されることによる、ＺＤ６１での損失が点火コイル出力エネルギ損失の本質である。そこで、イオン電流検出電源用コンデンサ６２の充電経路と、２次コイル出力電流経路をＺＤ６１を含まない様に切り替えるようにすれば、点火コイルの出力エネルギの損失は、コンデンサ６２の充電エネルギのみであり、点火性能はほとんど低下しないイオン電流検出機能をもつ内燃機関用点火装置を構成することができる。 The charge amount charged in the ion current detection power supply capacitor 62 in FIG. 1 is about 2.7 uC to 8 uC, and the energy required for charging this charge amount is about 0.1 mJ to 1.32 mJ. The energy lost by charging differs depending on the internal combustion engine, but hardly affects the output energy of the ignition coil, which is required from 30 mJ to 90 mJ. On the other hand, the loss at ZD 61 is proportional to the discharge time between Vz and the plug gap, and the loss occurs as shown in FIG. In other words, in the energy output period of the secondary coil, the loss in ZD61 due to the continued breakdown of ZD61 and the formation of the secondary coil output current path after the completion of charging of capacitor 62 is the essence of the ignition coil output energy loss. It is. Therefore, if the charging path of the ion current detection power supply capacitor 62 and the secondary coil output current path are switched so as not to include the ZD 61, the output energy loss of the ignition coil is only the charging energy of the capacitor 62. Thus, an ignition device for an internal combustion engine having an ion current detection function in which the ignition performance hardly decreases can be configured.

イオン電流検出用電源用コンデンサ６２の充電が２次コイル電流経路切り替え素子８の通電状態移行前になされると、コンデンサ６２が充電されても２次コイル出力電流切り替え素子８が通電状態に以降した時にコンデンサ６２の放電経路が作成されてしまい充電電荷が放電されてしまう。ＺＤ６１での点火コイル出力エネルギの損失を抑制しようとすると２次コイル出力電流が少ない期間にコンデンサ６２の充電を行う必要があり点火コイルの出力エネルギ特性から、コンデンサ６２の充電期間は２次コイル出力期間、すなわちプラグギャップ間放電の終了真際に行うことが望ましい。よって、２次コイル電流経路切り替え素子の動作は、２次コイル電流の出力開始時期から通電状態となりコンデンサ６２の充電に最小限必要なエネルギを点火コイルに残す時期で遮断状態に移行する動作とすることで点火コイル出力エネルギの損失を最も抑制したコンデンサ６２の充電を行うことができる。 When the ion current detection power supply capacitor 62 is charged before the secondary coil current path switching element 8 is switched to the energized state, the secondary coil output current switching element 8 is switched to the energized state even if the capacitor 62 is charged. Sometimes the discharge path of the capacitor 62 is created and the charge is discharged. If it is going to suppress the loss of the ignition coil output energy in ZD61, it is necessary to charge the capacitor 62 when the secondary coil output current is small. From the output energy characteristic of the ignition coil, the charging period of the capacitor 62 is the secondary coil output. It is desirable to carry out the period, that is, at the end of the discharge between plug gaps. Therefore, the operation of the secondary coil current path switching element is an operation in which the energized state starts from the output start timing of the secondary coil current and shifts to the cut-off state when the energy necessary for charging the capacitor 62 is left in the ignition coil. Thus, the capacitor 62 can be charged with the least loss of ignition coil output energy.

すなわち図２に示すように、点火コイルの出力エネルギをＥ２、２次コイル電流経路切り替え素子遮断時の点火コイルの残留エネルギ（Ｅ２'）、コンデンサ６２をイオン電流検出電源電圧で充電するエネルギをＥｉｏｎとすると、Ｅ２'＝Ｅ２−Ｅｉｏｎであり、点火コイルがＥ２'のエネルギ出力をする時間Ｔ２'において２次コイル電流切り替え素子を遮断状態へ移行することが最も効率的にコンデンサ６２を充電することができる。 That is, as shown in FIG. 2, the output energy of the ignition coil is E2, the residual energy of the ignition coil (E2 ′) when the secondary coil current path switching element is shut off, and the energy for charging the capacitor 62 with the ion current detection power supply voltage is Eion. Then, E2 ′ = E2−Eion, and the transition of the secondary coil current switching element to the cut-off state at the time T2 ′ at which the ignition coil outputs the energy of E2 ′ most efficiently charges the capacitor 62. Can do.

Ｅ２'のエネルギ出力を行うＴ２'における２次コイル出力電流は点火コイルの特性により決定される値であり、２次コイル出力電流値により判断することができる。よって、順方向電流に対し遮断状態に移行させたい２次コイル出力電流でのオン保持電流特性をもつ素子を使用すればよい。又、２次電流経路切り替え素子の通電状態への移行の制御は、２次コイル電流が出力される前に発生する１次コイルの逆起電圧により通電状態への制御電圧を作成できる。 The secondary coil output current at T2 ′ that performs the energy output of E2 ′ is a value determined by the characteristics of the ignition coil, and can be determined from the secondary coil output current value. Therefore, an element having an on-holding current characteristic at the secondary coil output current to be shifted to the cutoff state with respect to the forward current may be used. Control of the transition of the secondary current path switching element to the energized state can create a control voltage to the energized state by the back electromotive voltage of the primary coil generated before the secondary coil current is output.

又、１次電流通電開始時までに、２次コイル電流経路切り替え素子８を通電状態にしておくことで２次コイル低圧側に配置されるイオン電流検出電源用コンデンサ６２の充電電荷を放電することができ、１次電流通電開始時に２次コイルに誘導される高電圧Ｖ２ｏｎはＶ２ｏｎ＝バッテリ電圧（Ｖ１）×１次／２次コイル巻数比（ｎ１／ｎ２）の電圧のみとなるため、１次電流通電開始時に２次コイルへ誘導される高電圧を抑制することができる。 Further, by charging the secondary coil current path switching element 8 in the energized state before starting the primary current energization, the charge of the ion current detection power supply capacitor 62 disposed on the secondary coil low voltage side is discharged. The high voltage V2on induced in the secondary coil at the start of energization of the primary current is only the voltage V2on = battery voltage (V1) × primary / secondary coil turns ratio (n1 / n2). A high voltage induced to the secondary coil at the start of current application can be suppressed.

２次コイル低圧側にイオン電流検出電源回路とイオン電流増幅回路をもつ内燃機関用点火装置において、１次電流通電開始時の２次コイルへの誘導される高電圧を最小とするためには、２次コイル低圧側とＧＮＤ間の電位差を無くしておく必要がある。つまり１次電流通電開始時にはコンデンサ６２の放電がなされていなければならない。すなわちコンデンサ６２の放電動作は、点火信号の入力から１次電流遮断素子制御回路の遅延時間と１次電流遮断素子の動作遅延時間を合わせた時間内で終了しなければならない。 In an internal combustion engine ignition device having an ion current detection power supply circuit and an ion current amplification circuit on the secondary coil low voltage side, in order to minimize the high voltage induced to the secondary coil at the start of the primary current energization, It is necessary to eliminate the potential difference between the secondary coil low voltage side and GND. That is, the capacitor 62 must be discharged at the start of primary current application. That is, the discharging operation of the capacitor 62 must be completed within a time obtained by combining the delay time of the primary current interrupting element control circuit and the operation delay time of the primary current interrupting element after the ignition signal is input.

点火信号入力から１次電流遮断素子制御回路の遅延時間をタイマ回路によって遅延時間を制御してもよいが、１次電流遮断素子のゲートエミッタ間容量の充電による遅延時間を制御したほうが回路を簡素化でき望ましい。 The delay time of the primary current cutoff element control circuit may be controlled by the timer circuit from the ignition signal input, but the circuit is simpler if the delay time due to charging of the capacitance between the gate and emitter of the primary current cutoff element is controlled. This is desirable.

図３においてコンデンサ６２の放電動作を示す。点火信号の入力から１次電流遮断素子制御回路の遅延時間をＴｄ１、１次電流遮断素子の遅延時間をＴｄ２、１次電流遮断素子のゲート−エミッタ間容量をＣｉｅｓ、ゲートの直列抵抗をＲｇ、１次電流遮断素子のゲートスレッシュ電圧をＶｇｔｈ、１次電流遮断素子５のゲート駆動電圧をＶｇｄ、コンデンサ６２の放電時間をＴｆ、コンデンサ６２の容量をＣｉｏｎ，コンデンサ６２が放電する経路の直流抵抗をＲｅｓｒ、ＺＤ６１により充電されるコンデンサ６２の充電電圧をＶｉｏｎ、２次電流経路切り替え素子８のオン電圧をＶｆとすると、点火信号入力から１次電流通電開始までの遅延時間とコンデンサ６２の放電時間は（Ｔｄ１＋Ｔｄ２）＞Ｔｆの関係になければならない。すなわち、｛Ｔｄ１−Ｃｉｅｓ×Ｒｇ×ｌｎ（１−Ｖｇｔｈ／Ｖｇｄ）｝＞−Ｃｉｏｎ×Ｒｅｓｒ×ｌｎ（Ｖｆ／Ｖｉｏｎ）の関係式を満たす必要があり、１次電流遮断素子５のゲート直流抵抗ＲｇはＲｇ＞｛（Ｃｉｏｎ×Ｒｅｓｒ）／Ｃｉｅｓ｝×｛ｌｎ（Ｖｆ／Ｖｉｏｎ）／ｌｎ（１−Ｖｇｔｈ／Ｖｇｄ）｝となる必要がある。 FIG. 3 shows the discharging operation of the capacitor 62. From the input of the ignition signal, the delay time of the primary current interrupting element control circuit is Td1, the delay time of the primary current interrupting element is Td2, the gate-emitter capacitance of the primary current interrupting element is Cies, the series resistance of the gate is Rg, The gate threshold voltage of the primary current interrupting element is Vgth, the gate drive voltage of the primary current interrupting element 5 is Vgd, the discharge time of the capacitor 62 is Tf, the capacity of the capacitor 62 is Cion, and the DC resistance of the path through which the capacitor 62 is discharged is When the charging voltage of the capacitor 62 charged by Resr and ZD61 is Vion, and the on-voltage of the secondary current path switching element 8 is Vf, the delay time from the ignition signal input to the start of energization of the primary current and the discharging time of the capacitor 62 are The relationship must be (Td1 + Td2)> Tf. That is, {Td1-Cies * Rg * ln (1-Vgth / Vgd)}>-Cion * Resr * ln (Vf / Vion) must be satisfied, and the gate direct current resistance Rg of the primary current interrupting element 5 must be satisfied. Rg> {(Cion × Resr) / Cies} × {ln (Vf / Vion) / ln (1−Vgth / Vgd)}.

コンデンサ６２には２次コイル電流切り替え素子８が並列に配置されており、コンデンサ６２の放電動作を行うことが可能である。１次電流遮断素子５のゲート直列抵抗を上述の範囲で調整し、点火信号による２次コイル電流切り替え素子８の通電状態への移行を行うことによって１次電流通電開始時に２次コイルへ誘導される高電圧を抑制し内燃機関の点火時期の進角（過早点火）を防ぐことができる。 The secondary coil current switching element 8 is arranged in parallel with the capacitor 62, and the capacitor 62 can be discharged. By adjusting the gate series resistance of the primary current interrupting element 5 in the above-described range and shifting to the energized state of the secondary coil current switching element 8 by the ignition signal, the primary current interrupting element 5 is induced to the secondary coil at the start of energizing the primary current. Therefore, it is possible to prevent the advance timing (premature ignition) of the ignition timing of the internal combustion engine.

本発明は組み合わされる１次及び２次コイルに依存することなく、外部からの独立した制御信号を必要とせずに２次コイル電流経路を切り替えてイオン電流検出用電源回路での点火コイルの出力エネルギ損失を抑制し、１次電流通電開始時に２次コイルに生じる高電圧を抑制することができるイオン電流検出機能付き内燃機関用点火装置を実現できる。 The present invention does not depend on the combined primary and secondary coils, and switches the secondary coil current path without requiring an independent external control signal so that the output energy of the ignition coil in the ion current detection power supply circuit can be switched. An ignition device for an internal combustion engine with an ion current detection function that can suppress loss and suppress a high voltage generated in the secondary coil at the start of primary current energization can be realized.

本発明の実施例は、１次電流遮断素子による電子制御によって１次電流がオンオフされる１次コイル３１と前記１次コイルに電磁結合されて点火プラグに高電圧を供給する２次コイル３２と、前記１次コイルと前記２次コイルを内包するコイルケースを備える内燃機関用点火装置において、具体的には参考例として示す図４の様な回路によって、２次コイル低圧側にイオン電流検出用電源回路６とイオン電流増幅回路７を配置し、イオン電流検出用電源電圧作成用ＺＤ６２及びコンデンサ６２と並列に２次電流経路切り替え素子としてサイリスタ８を接続する。サイリスタは順方向のバイアス状態において、オントリガを入力することによって通電状態へ移行し自身の順方向電流により通電状態を保持でき、遮断状態の移行は順方向電流が自身の通電状態を保持できる保持電流以下に低下することによって成される。本発明において、サイリスタ８の遮断状態への移行はイオン電流検出電源用コンデンサ６２の充電動作の開始を意味し、サイリスタ８の保持電流特性によってコンデンサ６２の充電開始時期を決定する。 An embodiment of the present invention includes a primary coil 31 in which a primary current is turned on and off by electronic control by a primary current interrupting element, and a secondary coil 32 that is electromagnetically coupled to the primary coil and supplies a high voltage to a spark plug. In the internal combustion engine ignition device having a coil case containing the primary coil and the secondary coil, specifically, the circuit shown in FIG. A power supply circuit 6 and an ion current amplification circuit 7 are arranged, and a thyristor 8 is connected as a secondary current path switching element in parallel with the ion current detection power supply voltage creation ZD 62 and the capacitor 62. In the forward bias state, the thyristor shifts to the energized state by inputting an on-trigger and can maintain the energized state by its own forward current. The cut-off state transition is a holding current that allows the forward current to maintain its energized state. This is done by lowering to: In the present invention, the transition of the thyristor 8 to the cutoff state means the start of the charging operation of the ion current detection power supply capacitor 62, and the charging start timing of the capacitor 62 is determined by the holding current characteristics of the thyristor 8.

サイリスタ８のゲート入力は、１次電流遮断素子５と１次コイル３１の中間とを分圧抵抗９を介して接続されており、１次コイル３１の電流遮断時に発生する逆起電圧によってサイリスタ８の通電状態への移行を行う。サイリスタ８のゲートには動作安定もかねたコンデンサ１０が配置されており、１次コイル３１の逆起電圧の分圧電圧が２次コイル電流の出力開始までにサイリスタ８のオントリガ電圧を下回っても、サイリスタゲート電圧を通電状態に保つ様にサイリスタゲート電圧の低下を抑制する。２次コイル電流はプラグギャップ間を介してＧＮＤ→プラグ高圧電極→２次コイル→サイリスタ→ＧＮＤの経路を持ち、点火コイル出力エネルギを低下させるイオン電流検出用電源６を含まない。よって、内燃機関の点火時期において点火コイルの出力エネルギを低下させることなくプラグギャップ間に供給することができる。２次コイル放電電流がサイリスタ８の保持電流を下回ると、サイリスタ８は遮断状態へ移行しイオン電流検出電源電圧作成用ＺＤ６１がブレークダウンし、ＺＤ６１のＶｚでコンデンサ６２を充電すると共にプラグギャップ間放電の終了まで２次コイル出力電流の経路を作成する。 The gate input of the thyristor 8 is connected between the primary current interrupting element 5 and the middle of the primary coil 31 via the voltage dividing resistor 9, and the thyristor 8 is generated by a counter electromotive voltage generated when the current of the primary coil 31 is interrupted. Transition to the energized state. Capacitor 10 that is also stable in operation is arranged at the gate of thyristor 8, so that even if the divided voltage of the back electromotive voltage of primary coil 31 falls below the on-trigger voltage of thyristor 8 before the start of secondary coil current output. The thyristor gate voltage is prevented from decreasing so as to keep the thyristor gate voltage in an energized state. The secondary coil current has a path of GND → plug high voltage electrode → secondary coil → thyristor → GND through the plug gap, and does not include the ion current detection power source 6 for reducing the ignition coil output energy. Therefore, it can be supplied between the plug gaps without reducing the output energy of the ignition coil at the ignition timing of the internal combustion engine. When the secondary coil discharge current falls below the holding current of the thyristor 8, the thyristor 8 shifts to a cut-off state, the ion current detection power supply voltage creation ZD61 breaks down, charges the capacitor 62 with Vz of ZD61, and discharges between plug gaps. The path of the secondary coil output current is created until the end of.

図５において点火信号入力時にコンデンサ６２を放電し、１次電流通電開始時に２次コイルに発生する高電圧を抑制するイオン電流検出機能を持つ内燃機関用点火装置の実施例を示す。１次電流通電開始時において、コンデンサ６２のサイリスタ８による放電動作は、点火信号を微分回路１２（点火信号立ち上がり時期検出手段）に入力し微分回路出力を積分することによって安定したトリガ動作を行う。サイリスタ８の通電状態への移行後はコンデンサ６２の放電電流により通電状態が保持され、サイリスタ８のＶｆまで放電がなされる。１次電流通電開始時期は１次電流遮断素子５のゲート直列抵抗１１によって遅延時間を調整されているため、コンデンサ６２の電荷はサイリスタ８のＶｆまで放電される。万が一微少電流がサイリスタ８の順方向に流れていても、１次電流通電開始時に２次コイル３２に誘導される高電圧によりサイリスタ８は逆方向にバイアスされ強制的に遮断状態となる。 FIG. 5 shows an embodiment of an internal combustion engine ignition device having an ion current detection function for discharging a capacitor 62 when an ignition signal is input and suppressing a high voltage generated in a secondary coil when the primary current energization is started. At the start of energization of the primary current, the discharging operation of the capacitor 62 by the thyristor 8 performs a stable trigger operation by inputting the ignition signal to the differentiation circuit 12 (ignition signal rise timing detection means) and integrating the differentiation circuit output. After the transition to the energized state of the thyristor 8, the energized state is maintained by the discharge current of the capacitor 62, and the thyristor 8 is discharged to Vf. Since the delay time is adjusted by the gate series resistance 11 of the primary current interrupting element 5 at the primary current energization start timing, the charge of the capacitor 62 is discharged to Vf of the thyristor 8. Even if a very small current flows in the forward direction of the thyristor 8, the thyristor 8 is biased in the reverse direction by the high voltage induced in the secondary coil 32 when the primary current energization is started, and is forcibly cut off.

プラグギャップ間放電が終了し、内燃機関が燃焼状態にあればコンデンサ６２の充電電荷は火炎を経路として放電し、コンデンサ６２の放電電流はイオン電流増幅回路７によって任意の増幅率の出力電圧波形として得ることができる。 When the plug gap discharge is completed and the internal combustion engine is in a combustion state, the charge of the capacitor 62 is discharged through the flame, and the discharge current of the capacitor 62 is converted into an output voltage waveform of an arbitrary amplification factor by the ion current amplifier circuit 7. Obtainable.

以上のように、本発明の実施の形態について説明したが、実施の形態は上記形態に特に限定されるものではない。当該点火装置が必要なあらゆるエンジンに使用できるものであり、又２次コイル電流経路切り替え手段は、通電状態への移行を２次コイル電流の通電開始時に行い、遮断状態への移行を点火コイル特性とイオン電流検出性上要求されるイオン電流検出用電源電圧による２次コイル電流値により行うものであれば必ずしもサイリスタでなくとも良い。この発明の精神に基づき当業者が行いうる種々の変形的形態、改良的形態で実施することも可能である。 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 the ignition device, and the secondary coil current path switching means performs the transition to the energized state at the start of energization of the secondary coil current, and the transition to the shut-off state by the ignition coil characteristics. The thyristor is not necessarily required as long as it is performed by the secondary coil current value based on the ion current detection power supply voltage required for ion current detection. Various modifications and improvements that can be made by those skilled in the art based on the spirit of the present invention are also possible.

本発明の内燃機関用点火装置の回路図Circuit diagram of ignition device for internal combustion engine of the present invention 本発明の内燃機関用点火装置でのイオン電流検出電源用コンデンサ充電動作波形Capacitor charging operation waveform for ion current detection power source in ignition device for internal combustion engine of the present invention 本発明の内燃機関用点火装置でのイオン電流検出電源用コンデンサ放電動作波形Capacitor discharge operation waveform for ion current detection power source in ignition device for internal combustion engine of the present invention 本発明の内燃機関用点火装置の実施例Embodiment of ignition device for internal combustion engine of the present invention 点火信号入力時にイオン電流検出電源用コンデンサを放電する当該発明の内燃機関点火装置での実施例Embodiment of the internal combustion engine ignition device of the present invention in which a capacitor for an ion current detection power supply is discharged when an ignition signal is input 従来のイオン電流検出機能をもつ内燃機関用点火装置の回路図Circuit diagram of conventional internal combustion engine ignition device having ion current detection function 従来のイオン電流検出機能をもつ内燃機関用点火装置の動作波形図Operation waveform diagram of conventional internal combustion engine ignition device with ion current detection function

符号の説明Explanation of symbols

１バッテリ
２点火プラグ
３点火コイル
４制御回路
５１次電流遮断素子
６イオン電流検出電源回路
７イオン電流増幅回路 DESCRIPTION OF SYMBOLS 1 Battery 2 Spark plug 3 Ignition coil 4 Control circuit 5 Primary current interruption element 6 Ion current detection power supply circuit 7 Ion current amplification circuit

Claims

電子制御される１次電流遮断素子により１次電流がオンオフ制御される１次コイルと、前記１次コイルに電磁結合されて点火プラグに高電圧を供給する２次コイルと、２次コイル低圧側にイオン電流検出用電源回路とイオン電流増幅回路が配置され外部からの信号入力を必要としない自立制御によって２次コイル出力電流経路を切り替える手段とを備えたことを特徴とする内燃機関用点火装置。 A primary coil whose primary current is on / off controlled by an electronically controlled primary current interrupting element, a secondary coil that is electromagnetically coupled to the primary coil and supplies a high voltage to the spark plug, and a secondary coil low voltage side An ignition device for an internal combustion engine, comprising: a power source circuit for detecting an ion current; and an ion current amplifier circuit, and means for switching a secondary coil output current path by self-sustained control that does not require external signal input. .

１次コイルと２次コイルとが電磁結合され、当該各コイルにより２次側に所定の高電圧を発生させる内燃機関用点火装置であって、前記１次コイル側には１次電流をオンオフ制御する１次電流遮断素子を備え、前記２次コイルの低圧側には燃焼中のシリンダ内に発生するイオン電流を検出するためのイオン電流検出用電源回路とイオン電流増幅回路とを備えた内燃機関用点火装置において、前記１次コイルに入力される点火信号を微分する微分回路と、当該微分回路によって構成される点火信号立ち上がり時期検出手段と、当該点火信号の立ち上がり時期検出手段からの信号によって２次コイル出力電流経路を切り替える２次電流経路切り替え手段とを備え、当該２次電流経路切り替え手段は通電状態へ移行させた後にイオン電流検出電源の充電電荷を１次電流遮断素子の駆動回路に点火信号が入力されてから１次電流遮断素子が通電開始するまでの遅延時間内で放電し１次電流通電開始時に２次コイルに発生する高電圧の抑制手段であることを特徴とする内燃機関用点火装置。 An ignition device for an internal combustion engine in which a primary coil and a secondary coil are electromagnetically coupled, and each coil generates a predetermined high voltage on the secondary side, and the primary current is turned on and off on the primary coil side An internal combustion engine having an ion current detecting power supply circuit and an ion current amplifying circuit for detecting an ion current generated in a burning cylinder on the low pressure side of the secondary coil. In the ignition device, a differential circuit for differentiating the ignition signal input to the primary coil, an ignition signal rise timing detection means constituted by the differentiation circuit, and a signal from the rise timing detection means of the ignition signal Secondary current path switching means for switching the secondary coil output current path, and the secondary current path switching means is switched to the energized state after the ion current detection power supply High voltage generated in the secondary coil when the electric current is discharged within the delay time from when the ignition signal is input to the drive circuit of the primary current interrupting element until the primary current interrupting element starts energization and when the primary current energization starts. An ignition device for an internal combustion engine, characterized by comprising: