JP4200804B2

JP4200804B2 - Ignition device for current interrupting internal combustion engine

Info

Publication number: JP4200804B2
Application number: JP2003113010A
Authority: JP
Inventors: 慎庄司; 琢麿鮎沢
Original assignee: Kokusan Denki Co Ltd
Current assignee: Mahle Electric Drive Systems Co Ltd
Priority date: 2003-04-17
Filing date: 2003-04-17
Publication date: 2008-12-24
Anticipated expiration: 2023-04-17
Also published as: JP2004316572A

Description

【０００１】
【発明の属する技術分野】
本発明は、電流遮断形の内燃機関用点火装置に関するものである。
【０００２】
【従来の技術】
内燃機関を点火する点火装置として、内燃機関により駆動される磁石発電機内に設けられた点火電源コイルを電源として点火用の高電圧を発生させる電流遮断形の点火装置が用いられている。
【０００３】
この種の点火装置は、例えば特許文献１に示されているように、点火電源コイルに対して並列に接続されて該点火電源コイルが一方の半波の出力電圧を発生したときに該点火電源コイルから駆動信号が与えられて導通状態になる主電流制御用スイッチと、導通状態にある主電流制御用スイッチを遮断状態にする遮断制御回路とを備えていて、主電流制御用スイッチを遮断状態にした時に点火電源コイルに誘起する電圧を昇圧手段により更に昇圧して点火用の高電圧を発生させる。
【０００４】
特許文献１に示されているように、主電流制御用スイッチとしては通常パワートランジスタが用いられ、該トランジスタのコレクタ・エミッタ回路が点火電源コイルの両端に並列に接続される。本明細書では、主電流制御用スイッチを構成するトランジスタを主電流制御用トランジスタと呼ぶ。
【０００５】
主電流制御用トランジスタのベースはベース電流供給用の抵抗器を通して点火電源コイルに結合され、点火電源コイルが一方の半波の出力電圧を発生した時に点火電源コイルからベース電流供給用抵抗器を通して主電流制御用トランジスタにベース電流が与えられて該トランジスタが導通状態になる。
【０００６】
主電流制御用トランジスタを遮断状態にする遮断制御回路は、主電流制御用トランジスタのコレクタ・エミッタ回路の両端の電圧を分圧して検出する抵抗分圧回路と、該抵抗分圧回路を通して検出される電圧が設定値以上になったときに導通状態になって主電流制御用トランジスタに供給されていたベース電流を該トランジスタから側路するように設けられた遮断制御用スイッチとにより構成される。遮断制御用スイッチとしては、特許文献１に示されたように、トランジスタが用いられる場合もあり、トランジスタに代えてサイリスタが用いられる場合もある。
【０００７】
点火電源コイルを流れていた電流を遮断した際に誘起する電圧を昇圧する昇圧手段としては、通常点火コイルが用いられる。点火コイルは点火電源コイルとは別個に設けるようにしてもよいが、この種の点火装置では、特許文献１にも示されているように、点火コイルの一次コイルを磁石発電機の固定子鉄心に巻回して、機関の回転に同期させて該点火コイルの一次コイルに交流電圧を誘起させる構成をとることにより、点火コイルの一次コイルを点火用電源コイルとして兼用することが多い。
【０００８】
このように構成された点火装置においては、点火電源コイルが一方の半波の出力電圧を発生した時に主電流制御用トランジスタにベース電流が与えられて該トランジスタが導通状態になる。これにより点火電源コイルが主電流制御用トランジスタのコレクタ・エミッタ回路を通して実質的に短絡され、点火電源コイルから主電流制御用トランジスタのコレクタ・エミッタ回路を通して短絡電流が流れる。
【０００９】
この短絡電流は点火電源コイルが発生する一方の半波の出力電圧の瞬時値が上昇していくに従って大きくなっていき、短絡電流の増大に伴って主電流制御用トランジスタのコレクタ・エミッタ間の電圧が上昇していくため、遮断制御回路の抵抗分圧回路を通して検出される電圧も上昇していく。
【００１０】
抵抗分圧回路を通して検出される電圧が設定値に達すると、遮断制御用スイッチが導通して主制御用トランジスタのベース電流を該トランジスタから側路するため、主制御用トランジスタが遮断状態になる。これにより、点火電源コイルを流れていた短絡電流が遮断されるため、点火電源コイルには、それまで流れていた電流を流し続けようとする極性の高い電圧が誘起し、この電圧が点火コイルにより昇圧されて点火用高電圧が発生させられる。この点火用高電圧は機関の気筒に取り付けれられた点火プラグに印加されるため、該点火プラグで火花放電が生じ、機関が点火される。
【００１１】
電流遮断形の点火装置では、製品毎の点火性能のばらつきを無くすために、電流の遮断値をほぼ一定にすることが好ましいが、トランジスタのコレクタ電流の大きさとコレクタエミッタ間電圧との間の関係は一定ではなく、トランジスタのｈfeの影響を受けて変動するため、上記のように、主電流制御用トランジスタのコレクタエミッタ間の電圧によりコレクタ電流（点火電源コイルの短絡電流）を間接的に検出して、点火電源コイルを流れる電流を遮断するタイミングを定めるようにした場合には、製品毎に電流の遮断値がばらついて点火性能にばらつきが生じるのを避けられなかった。製品毎の点火性能のばらつきを少なくするためには、回路を組み立てた後、主電流制御用トランジスタにベース電流を供給する抵抗器の抵抗値を微調整したり、トランジスタのコレクタエミッタ間の電圧を検出する抵抗分圧回路を構成する抵抗器の抵抗値を微調整したりする必要があったため、製造コストが高くなるのを避けられなかった。
【００１２】
なお、特許文献２に示されているように、電流の遮断値をできるだけ大きくするために、常に点火電源コイルの出力電圧がピークに達する位置で電流を遮断する提案がなされている。特許文献２に示された点火装置においては、主電流制御用トランジスタのコレクタ・エミッタ間の電圧を検出する抵抗分圧回路の出力端子間にピーク検出用のトランジスタのコレクタ・エミッタ回路を通してコンデンサを並列に接続するとともに、該ピーク検出用のトランジスタに主電流制御用トランジスタを通してベース電流を与える回路を設けている。
【００１３】
特許文献２に示された点火装置では、点火電源コイルが一方の半波の出力電圧を発生した時に主電流制御用トランジスタが導通状態になると同時に、ピーク検出用トランジスタが導通して抵抗分圧回路の出力端子間の電圧を低下させる。ピーク検出用トランジスタは、点火電源コイルが発生している一方の半波の出力電圧がピークに達するまでの間は導通状態を保持するため、該一方の半波の出力電圧がピークに達するまでの間は、抵抗分圧回路の出力電圧が遮断制御用のスイッチを導通させるレベルに達しない。点火電源コイルの一方の半波の出力電圧がピークに達すると、ピーク検出用トランジスタが遮断状態になるため、抵抗分圧回路の出力電圧が設定値に達して遮断制御用スイッチが導通し、主電流制御用トランジスタを遮断状態にする。
【００１４】
特許文献２に示された点火装置では、上記のようにして点火電源コイルの一方の半波の出力電圧がピークに達する位置で主電流制御用トランジスタを遮断状態にして点火動作を行わせるため、電流の遮断値を最大にして高い点火用高電圧を得ることができる。
【００１５】
なお点火電源コイルを用いることなく、バッテリから点火コイルの一次コイルと一次電流制御用スイッチとを通して流しておいた一次電流を遮断することにより点火用の高電圧を得るバッテリ式の電流遮断形点火装置においては、特許文献３に示されているように、点火コイルの一次電流を検出する電流検出用抵抗器と、この抵抗器により検出される一次電流を一定に保つように一次電流制御用スイッチを構成するトランジスタを制御する電流制御回路とを設けて、電流の遮断値を常に一定に保つように制御することが知られている。
【００１６】
【特許文献１】
実開昭５４−５８５２４号公報
【００１７】
【特許文献２】
特開昭５６−１０１０６６号公報
【００１８】
【特許文献３】
特開平４−３３４７６５号公報
【００１９】
【発明が解決しようとする課題】
上記のように、従来の電流遮断形の点火装置では、主電流制御用スイッチの両端の電圧から間接的に点火電源コイルの短絡電流を検出して、その検出値に基づいて点火時期を定めていたため、電流の遮断値のばらつきを少なくして、製品毎の点火性能のばらつきを少なくすることが難しいという問題があった。
【００２０】
また特許文献２に示されたように、常に点火電源コイルの出力電圧のピークで点火動作を行わせるようにした場合には、電流の遮断値を最大にして点火用高電圧の波高値を高くすることができるが、このように構成した場合には、点火時期が常にほぼ一定になるため、機関の高速回転時の性能を向上させるために点火時期を進角させることができないという問題があった。更にこのように構成した場合には、機関の高速回転時に電流の遮断値が大きくなり過ぎて、点火用高電圧が高くなり過ぎ、点火プラグの寿命が短くなるおそれがあった。
【００２１】
なおバッテリ式の電流遮断形点火装置では、特許文献３に示されているように、一次電流をフィードバック制御する電流制御回路を設けることにより、機関の始動時から高速回転時まで電流の遮断値を一定に保つことができるが、バッテリを用いずに、機関により駆動される発電機内に設けられる点火用電源コイルを電源として点火動作を行わせる電流遮断形の点火装置では、機関の始動時に点火電源コイルから十分な電圧を発生させることができないため、特許文献３に示されたような電流制御回路を設けて電流の遮断値を一定にする制御を行わせることはできない。また構成の簡素化を図り、コストの低減を図ることを重視する電流遮断形の点火装置においては、電流をフィードバック制御する制御回路を設けるようなことは避けるのが好ましい。
【００２２】
本発明の目的は、無調整で高速回転時の電流の遮断値をほぼ一定にすることができるようにして、高価な電子部品や面倒な調整作業を行うことなく点火性能のばらつきを少なくすることができるだけでなく、機関の回転速度の上昇に伴って点火時期を進角させることができる電流遮断形内燃機関用点火装置を提供することにある。
【００２３】
【課題を解決するための手段】
本発明は、１対の端子を有して一方の端子の電位が他方の端子の電位よりも高くなる極性を示す一方の半波の出力電圧と該一方の半波の出力電圧と逆極性の他方の半波の出力電圧とからなる交流電圧を内燃機関の回転に同期して発生する点火電源コイルと、点火電源コイルに対して並列に接続されて点火電源コイルが一方の半波の出力電圧を発生したときに点火電源コイルから駆動信号が与えられて導通状態になる主電流制御用スイッチと、導通状態にある主電流制御用スイッチを遮断状態にする遮断制御回路と、主電流制御用スイッチを遮断状態にした時に点火電源コイルに誘起する電圧を昇圧して点火用の高電圧を発生させる昇圧手段とを備えた電流遮断形内燃機関用点火装置に適用される。
【００２４】
本発明においては、上記遮断制御回路が、主電流制御用スイッチを通して流れる電流を検出する電流検出器を備えて、点火電源コイルの一方の半波の出力電圧がピークに達するタイミング及び電流検出器により検出された電流が設定値に達するタイミングのうちの早いほうのタイミングを検出した時に主電流制御用スイッチを遮断状態にするように構成される。
【００２５】
上記のように、点火電源コイルを短絡したときに流れる電流を検出する電流検出器を設けて、点火電源コイルの一方の半波の出力電圧がピークに達するタイミング及び電流検出器により検出された電流が設定値に達するタイミングのうちの早いほうのタイミングを検出した時に主電流制御用スイッチを遮断状態にするように構成すると、点火電源コイルの誘起電圧が低い機関の始動時及び低速回転時には、短絡電流がピークに達したときに該電流を遮断して点火動作を行わせることができるため、機関の始動時及び低速回転時に電流の遮断値が不足して点火性能が低下するのを防ぐことができる。
【００２６】
また機関の高速回転時には、短絡電流が設定された値に達した時に該電流を遮断して点火動作を行わせることができるため、電流の遮断値をほぼ一定にしてほぼ一定の点火用高電圧を得ることができ、点火プラグの過度の消耗を防ぎつつ点火動作を安定に行わせることができる。
【００２７】
更に機関の高速回転時には、点火用電源コイルの誘起電圧の波高値の上昇に伴って、短絡電流が遮断値に達する位相が進んでいくため、点火時期を進角させることができる。
【００２８】
本発明の好ましい態様では、上記遮断制御回路が、点火電源コイルの他方の端子側で主電流制御用スイッチに対して直列に接続された電流検出用抵抗器と、点火電源コイルの一方の端子に一端が接続された電流制限用抵抗器と、一端が電流制限用抵抗器を通して点火電源コイルの一方の端子に接続されるとともに他端が電流検出用抵抗器を通して点火電源コイルの他方の端子に接続されたピーク検出用スイッチと、点火電源コイルが一方の半波の出力電圧を発生してから該一方の半波の出力電圧がピークに達するまでの間点火電源コイルからピーク検出用スイッチに駆動信号を与えて該ピーク検出用スイッチを導通状態に保持するピーク検出用スイッチ駆動回路と、電流制限用抵抗器の他端と点火電源コイルの他方の端子との間の電圧を検出する電圧検出回路と、電圧検出回路が検出した電圧が設定値以上になったときに動作して主電流制御用スイッチへの駆動信号の供給を阻止して主電流制御用スイッチを遮断状態にする遮断制御用スイッチとにより構成される。
【００２９】
上記のように構成すると、内燃機関の回転速度が進角開始回転速度未満の時には点火電源コイルの一方の半波の出力電圧がピークに達するタイミングで電圧検出回路により検出される電圧が設定値以上になり、内燃機関の回転速度が進角開始回転速度以上になったときには点火電源コイルの一方の半波の出力電圧がピークに達するタイミングよりも前のタイミングで電圧検出回路により検出される電圧が設定値以上になるように遮断制御回路の回路定数（電流検出用抵抗器の抵抗値）を設定することにより、機関の始動時には短絡電流が最大になるタイミングで点火動作を行わせて十分な点火性能を得ることができ、機関の高速回転時には電流の遮断値をほぼ一定に保って、安定な点火動作を行わせることができる。
【００３０】
また機関の高速回転時には、点火電源コイルの出力電圧の波高値の上昇に伴って、電圧検出回路により検出される電圧が設定値に達するタイミングが進角していくため、回転速度の上昇に伴って点火時期を進角させる特性を得ることができる。
【００３１】
上記主電流制御用スイッチは、点火電源コイルの一方の端子にコレクタ・エミッタ回路の一端が接続された状態でコレクタ・エミッタ回路が点火電源コイルに対して並列に接続されて、点火電源コイルが一方の極性の半波の出力電圧を発生したときに点火電源コイル側からベース電流が与えられて導通状態になる主電流制御用トランジスタにより構成することができる。
【００３２】
この場合遮断制御回路は、主電流制御用スイッチと点火電源コイルの他方の端子との間に挿入されて主電流制御用スイッチに対して直列に接続された電流検出用抵抗器と、点火電源コイルの一方の端子に一端が接続された電流制限用抵抗器と、電流制限用抵抗器の他端にコレクタが接続され、エミッタが電流検出用抵抗器を通して点火電源コイルの他方の端子に接続されたＮＰＮ形のピーク検出用トランジスタと、点火電源コイルの一方の端子とピーク検出用トランジスタのベースとの間に電流制限素子を通して接続されたピーク検出用コンデンサと、ピーク検出用トランジスタのベースと点火電源コイルの他方の端子との間にアノードを点火電源コイルの他方の端子側に向けて接続されたコンデンサ放電用ダイオードと、電流制限用抵抗器の他端と点火電源コイルの他方の端子との間の電圧を検出する電圧検出回路と、電圧検出回路が検出した電圧が設定値以上になったときに導通状態になって主電流制御用スイッチへの駆動信号の供給を阻止する遮断制御用スイッチとを備えた構成とすることができる。
【００３３】
また上記遮断制御回路は、主電流制御用スイッチと点火電源コイルの他方の端子との間に挿入されて主電流制御用スイッチに対して直列に接続された電流検出用抵抗器と、点火電源コイルの一方の端子に一端が接続された電流制限用抵抗器と、電流制限用抵抗器の他端にエミッタが接続され、コレクタが電流検出用抵抗器を通して点火電源コイルの他方の端子に接続されたＰＮＰ形のピーク検出用トランジスタと、点火電源コイルの他方の端子とピーク検出用トランジスタのベースとの間に電流制限素子を通して接続されたピーク検出用コンデンサと、ピーク検出用トランジスタのベースと点火電源コイルの一方の端子との間にカソードを点火電源コイルの一方の端子側に向けて接続されたコンデンサ放電用ダイオードと、電流制限用抵抗器の他端と点火電源コイルの他方の端子との間の電圧を検出する電圧検出回路と、電圧検出回路が検出した電圧が設定値以上になったときに導通状態になって主電流制御用スイッチへの駆動信号の供給を阻止する遮断制御用スイッチとを備えた構成とすることもできる。
【００３４】
【発明の実施の形態】
以下図面を参照して本発明の実施形態を詳細に説明する。
【００３５】
図１は本発明の第１の実施形態の１気筒分の構成を示したもので、同図において、１は点火電源コイルを兼ねる一次コイル２と二次コイル３とを有する昇圧手段としての点火コイルである。点火コイルの一次コイル２及び二次コイル３は図示しない内燃機関により駆動される磁石発電機の固定子鉄心４に巻回されている。一次コイル（点火電源コイル）２は、その両端に１対の端子２ａ及び２ｂを有していて、一方の端子２ａの電位が他方の端子２ｂの電位よりも高くなる極性の一方の半波の電圧Ｖ1と、この電圧Ｖ1と逆極性の他方の半波の電圧Ｖ2とからなる交流電圧を、機関の回転に同期して発生する。点火コイルの一次コイル２の一端は、二次コイル３の一端と共に鉄心４を通して接地され、二次コイル３の他端は内燃機関の気筒に取り付けられた点火プラグ５の非接地側端子に高圧コードを通して接続されている。
【００３６】
点火電源コイル２の一方の端子２ａには、ダーリントン接続されたＮＰＮ形の複合トランジスタからなる主電流制御用トランジスタＴＲ1のコレクタが接続され、該トランジスタＴＲ1のエミッタと点火電源コイル２の他方の端子２ｂとの間に電流検出用抵抗器Ｒ1が接続されている。
【００３７】
またトランジスタＴＲ1のベースに抵抗器Ｒ2の一端が接続され、該トランジスタのコレクタと抵抗器Ｒ2の他端との間に抵抗器Ｒ3が、また抵抗器Ｒ2の他端と点火電源コイルの他方の端子２ｂとの間にアノードを点火電源コイルの他方の端子側に向けたダイオードＤ1がそれぞれ接続されている。
【００３８】
この例では、トランジスタＴＲ1により、点火電源コイルに対して並列に接続されて前記点火電源コイルが一方の半波の出力電圧を発生したときに点火電源コイルから駆動信号が与えられて導通状態になる主電流制御用スイッチ６が構成され、抵抗器Ｒ3及びＲ2により、点火電源コイル２が一方の半波の電圧Ｖ1を発生したときに点火電源コイルから主電流制御用スイッチ６に駆動信号（該スイッチを導通状態にするための信号）を与える主電流制御用スイッチ駆動回路が構成されている。
【００３９】
当然のことながら、電流検出用抵抗器Ｒ1の抵抗値は、点火動作に悪影響を与えないように、十分に小さく設定されている。
【００４０】
また抵抗器Ｒ2の他端にＰＮＰトランジスタＴＲ2のエミッタが接続され、トランジスタＴＲ2のコレクタと点火電源コイルの他方の端子２ｂとの間に抵抗器Ｒ4が接続されている。トランジスタＴＲ2のベース及びコレクタにそれぞれＮＰＮトランジスタＴＲ3のコレクタ及びベースが接続され、トランジスタＴＲ2及びＴＲ3により、サイリスタと同等の働きをするスイッチが構成されている。
【００４１】
また点火電源コイル２ａの一方の端子２ａに抵抗値が十分に大きい電流制限用抵抗器Ｒ5の一端が接続され、該抵抗器Ｒ5の他端にＮＰＮ形のピーク検出用トランジスタＴＲ4のコレクタが接続されている。トランジスタＴＲ4のエミッタは、主電流制御用トランジスタＴＲ1のエミッタに共通接続されて、電流検出用抵抗器Ｒ1を通して点火電源コイル２の他方の端子２ｂに接続されている。
【００４２】
ピーク検出用トランジスタＴＲ4のベースと点火電源コイル２の一方の端子２ａとの間に電流制限素子としての抵抗器Ｒ6を通してピーク検出用コンデンサＣ1が接続され、トランジスタＴＲ4のベースと点火電源コイル２の他方の端子２ｂとの間に、アノードを点火電源コイル２の他方の端子２ｂ側に向けたコンデンサ放電用ダイオードＤ2が接続されている。
【００４３】
トランジスタＴＲ4のコレクタに抵抗器Ｒ7と抵抗器Ｒ8との直列回路の一端が接続され、抵抗器Ｒ7及びＲ8の直列回路の他端と点火電源コイル２の他方の端子との間にカソードを点火電源コイルの他方の端子２ｂ側に向けたダイオードＤ3が接続されている。この例では、抵抗器Ｒ7及びＲ8とダイオードＤ3とにより、電流制限用抵抗器Ｒ6の他端と点火電源コイル２の他方の端子２ｂとの間の電圧を検出する電圧検出回路７が構成されている。
【００４４】
図１に示した例では、ピーク検出用トランジスタＴＲ4により、一端が電流制限用抵抗器Ｒ5を通して点火電源コイルの一方の端子２ａに接続されるとともに他端が電流検出用抵抗器Ｒ1を通して点火電源コイルの他方の端子２ｂに接続されたピーク検出用スイッチ８が構成されている。
【００４５】
また抵抗器Ｒ6とピーク検出用コンデンサＣ1とダイオードＤ2とにより、点火電源コイルが一方の半波の出力電圧Ｖ1を発生してから該一方の半波の出力電圧がピークに達するまでの間点火電源コイル２からピーク検出用スイッチに駆動信号を与えて該ピーク検出用スイッチを導通状態に保持するピーク検出用スイッチ駆動回路が構成されている。
【００４６】
更にトランジスタＴＲ2及びＴＲ3により、電圧検出回路７が検出した電圧が設定値以上になったときに導通状態になって主電流制御用スイッチ（主電流制御用トランジスタＴＲ1）６への駆動信号（ベース電流）の供給を阻止して該スイッチ６を遮断状態にする遮断制御用スイッチ９が構成されている。
【００４７】
図１に示した点火装置においては、主電流制御用スイッチ６と点火電源コイル２の他方の端子２ｂとの間に挿入されて主電流制御用スイッチ６に対して直列に接続された電流検出用抵抗器Ｒ1と、点火電源コイル２の一方の端子２ａに一端が接続された電流制限用抵抗器Ｒ6と、電流制限用抵抗器Ｒ6の他端にコレクタが接続され、エミッタが電流検出用抵抗器Ｒ1を通して点火電源コイルの他方の端子に接続されたＮＰＮ形のピーク検出用トランジスタＴＲ4と、点火電源コイル２の一方の端子２ａとピーク検出用トランジスタＴＲ4のベースとの間に電流制限素子Ｒ6を通して接続されたピーク検出用コンデンサＣ1と、ピーク検出用トランジスタＴＲ4のベースと点火電源コイル２の他方の端子２ｂとの間にアノードを点火電源コイル２の他方の端子側に向けて接続されたコンデンサ放電用ダイオードＤ2と、電流制限用抵抗器Ｒ6の他端と点火電源コイルの他方の端子との間の電圧を検出する電圧検出回路７と、電圧検出回路７が検出した電圧が設定値以上になったときに導通状態になって主電流制御用スイッチ６への駆動信号の供給を阻止する遮断制御用スイッチ９とにより、点火電源コイル２の一方の半波の出力電圧Ｖ1がピークに達するタイミング及び電流検出器（図示の例では電流検出用抵抗器Ｒ1）により検出された電流が設定値に達するタイミングのうちの早いほうのタイミングを検出した時に主電流制御用スイッチ６を遮断状態にする遮断制御回路が構成されている。
【００４８】
図１に示した点火装置の動作は下記の通りである。内燃機関のクランク軸の回転に伴って点火電源コイル２が交流電圧を発生すると、その一方の半波の電圧Ｖ1により、抵抗器Ｒ3と抵抗器Ｒ2とを通して主電流制御用トランジスタＴＲ1にベース電流が与えられるため、このトランジスタＴＲ1（主電流制御用スイッチ）が導通状態になる。これにより、点火電源コイル２が実質的に短絡された状態になり、点火電源コイル２からトランジスタＴＲ1のコレクタ・エミッタ回路と電流検出用抵抗器Ｒ1とを通して短絡電流が流れる。
【００４９】
また点火電源コイルが一方の半波の出力電圧Ｖ1を発生すると、抵抗器Ｒ6とピーク検出用コンデンサＣ1とを通してピーク検出用トランジスタＴＲ4にベース電流が与えられる。これによりピーク検出用トランジスタＴＲ4が導通状態になり、抵抗器Ｒ7及びＲ8とダイオードＤ3とからなる電圧検出回路７の両端に印加される電圧を、電流検出用抵抗器Ｒ1の両端の電圧とトランジスタＴＲ4のコレクタエミッタ間の電圧との和の電圧に等しくする。
【００５０】
トランジスタＴＲ4が導通状態にあるときに該トランジスタのコレクタ・エミッタ回路を通して電圧検出回路７の両端に印加される電圧は、電流検出用抵抗器Ｒ1の両端の電圧に対応しており、この電圧は主電流制御用トランジスタＴＲ1を通して流れている短絡電流に相応している。点火電源コイル２に誘起する電圧の瞬時値の上昇に伴って短絡電流が増大していくため、電圧検出回路７に印加される電圧が上昇していくが、機関の始動時及び低速回転時には、電流検出用抵抗器Ｒ1の両端の電圧とトランジスタＴＲ4のコレクタエミッタ間の電圧との和の電圧を抵抗器Ｒ7とＲ8とにより分圧した電圧が設定値（トランジスタＴＲ2及びＴＲ3からなる遮断制御用スイッチ９を駆動するレベル）に達することはないため、点火電源コイルが発生している電圧Ｖ1がピークに達するまでの間に遮断制御用スイッチ９が駆動されることはない。
【００５１】
点火電源コイル２が発生している一方の半波の出力電圧Ｖ1がピークに達すると、ピーク検出用コンデンサＣ1の充電が停止するため、それまでピーク検出用トランジスタＴＲ4に流れていたベース電流が流れなくなり、ピーク検出用スイッチを構成するトランジスタＴＲ4が遮断状態にされる。
【００５２】
ピーク検出用トランジスタＴＲ4が遮断状態になると、電圧検出回路７に印加される電圧が高くなるため、該電圧検出回路７により検出される電圧（抵抗器Ｒ8の両端の電圧）が設定値に達し、遮断制御用スイッチ９が導通状態になる。これにより、主電流制御用トランジスタＴＲ1が遮断状態になるため、点火電源コイル２には、それまで流れていた短絡電流を流し続けようとする極性の高い電圧が誘起する。この電圧は昇圧手段としての点火コイル１により昇圧されるため、二次コイル３に点火用の高電圧が誘起し、該高電圧が点火プラグ５に印加されて点火動作が行われる。
【００５３】
点火電源コイル２が他方の半波の出力電圧Ｖ2を発生すると、ピーク検出用コンデンサＣ1の電荷が抵抗器Ｒ6と点火電源コイル２とダイオードＤ2とを通して放電した後、コンデンサＣ1が逆方向に充電される。
【００５４】
このように、機関の始動時及び低速回転時には、点火電源コイル２が発生した一方の半波の出力電圧Ｖ1がピークに達したときに主電流制御用トランジスタＴＲ1が導通状態から遮断状態にされて点火動作が行われる。
【００５５】
これに対し、機関の高速回転時には、点火電源コイル２が一方の半波の電圧Ｖ1を発生した後、ピーク検出用トランジスタＴＲ4かオン状態になっている間（電圧Ｖ1がピークに達するまでの間）に、主電流制御用トランジスタを流れる短絡電流が設定された一定の遮断値に達するようになり、短絡電流が一定の遮断値に達したときに電流検出用抵抗器Ｒ1の両端の電圧とトランジスタＴＲ4のコレクタエミッタ間の電圧との和の電圧を抵抗器Ｒ7とＲ8とにより分圧した電圧（電圧検出回路の出力電圧）が設定値に達するため、電圧Ｖ1がピークに達するタイミングよりも前のタイミングで遮断制御用スイッチ９が導通して主電流制御用トランジスタＴＲ1を遮断状態にするようになる。
【００５６】
遮断制御用スイッチ９が導通するタイミング（主電流制御用スイッチを流れてい短絡電流が一定の遮断値に達するタイミング）は、機関の回転速度の上昇による点火電源コイル２の半波の出力電圧Ｖ1の波高値の上昇に伴って早くなっていくため、機関の点火時期は機関の回転速度の上昇に伴って進角していく。
【００５７】
図１に示した点火装置においては、内燃機関の回転速度が進角開始回転速度未満のときに点火電源コイル２の一方の半波の出力電圧がピークに達するタイミングで電圧検出回路７により検出される電圧が設定値以上になり、内燃機関の回転速度が進角開始回転速度以上になったときには点火電源コイル２の一方の半波の出力電圧がピークに達するタイミングよりも前のタイミングで電圧検出回路７により検出される電圧が設定値以上になるように、遮断制御回路の回路定数（電流検出用抵抗器Ｒ1の抵抗値や、電圧検出回路を構成する抵抗器Ｒ7の抵抗値など）を設定しておくことにより、進角開始回転速度未満の回転速度領域では点火時期が一定となり、進角開始回転速度よりも高い領域では回転速度の上昇に伴って点火時期が進角していく特性を得ることができる。
【００５８】
また進角開始回転速度以上の領域では、主電流制御用トランジスタＴＲ1を通して流れる短絡電流が一定のレベル（遮断値）に達して電流検出用抵抗器Ｒ1の両端の電圧が所定のレベルに達し、電圧検出回路７により検出される電圧が設定値に達したときに電流が遮断されて点火動作が行われるため、電流の遮断値をほぼ一定にしてほぼ一定の点火用高電圧を発生させることができ、点火プラグの無用の消耗を防ぎつつ、安定な点火動作を行わせることができる。
【００５９】
主電流制御用トランジスタのコレクタエミッタ間電圧から短絡電流を間接的に検出して、その検出値に基づいて点火時期を定めるようにした従来の電流遮断形の点火装置においては、主電流制御用トランジスタのｈfeや、電圧検出回路を構成する抵抗器の抵抗値のばらつきが点火時期に与える影響が大きいため、製品毎の点火特性のばらつきを少なくするためには、回路を組み立てた後に、主電流制御用トランジスタにベース電流を与える回路の抵抗値や、トランジスタのコレクタエミッタ間電圧を検出する電圧検出回路の抵抗値をレーザトリミング等により微調整することが必要であったが、本発明のように、主電流制御用トランジスタを通して流れる短絡電流を直接検出してその検出値（電流検出用抵抗器の両端の電圧）が所定のレベルに達したときに電流を遮断するようにすると、遮断制御回路を構成する抵抗器の抵抗値の調整を行わなくても、点火性能のばらつきを許容範囲内に抑えることができる。
【００６０】
上記の実施形態では、主電流制御用スイッチとしてＮＰＮ形のトランジスタを用いているが、このスイッチはオンオフ制御が可能なものであれば良く、トランジスタに限定されるものではない。
【００６１】
また主電流制御用スイッチとしてトランジスタを用いる場合、該トランジスタ（主電流制御用トランジスタ）はＮＰＮ形のものに限られるものではなく、ＰＮＰ形の主電流制御用トランジスタを用いて、該トランジスタのコレクタ・エミッタ回路を点火電源コイルに対して並列に接続するようにしてもよい。
【００６２】
また上記の例では、遮断制御用スイッチ９としてトランジスタＴＲ2及びＴＲ3からなるものを用いたが、遮断制御用スイッチ９は、電圧検出回路７が検出した電圧が設定値以上になったときに導通状態になって主電流制御用スイッチ６への駆動信号の供給を阻止するスイッチであれば良く、トランジスタ以外のスイッチ素子からなるスイッチを遮断制御用スイッチ９として用いることもできる。例えば、図２に示した第２の実施形態のように、サイリスタＴｈを遮断制御用スイッチ９として用いることもできる。
【００６３】
図２に示した点火装置は、遮断制御用スイッチとしてサイリスタＴｈを用いている点を除き、図１に示した点火装置と同様に構成されている。
【００６４】
図１に示した実施形態では、ピーク検出用スイッチ８としてＮＰＮ形のトランジスタＴＲ4を用いたが、図３に示した第３の実施形態のように、ＰＮＰ形のトランジスタＴＲ4´により、ピーク検出用スイッチ８を構成するようにしてもよい。この場合は、トランジスタＴＲ4´のエミッタを電流制限用抵抗器Ｒ5の他端に接続し、トランジスタＴＲ4´のコレクタを電流検出用抵抗器Ｒ1を通して点火電源コイル２の他方の端子２ｂに接続する。またトランジスタＴＲ4´のベースと点火電源コイルの他方の端子２ｂとの間に抵抗器Ｒ6を通してピーク検出用コンデンサＣ1を接続し、トランジスタＴＲ4のベースと点火電源コイル２の一方の端子２ａとの間にコンデンサ放電用ダイオードＤ2を接続する。
【００６５】
なおピーク検出用スイッチ８は、トランジスタに限定されるものではなく、その一端［主電流が流れる回路（トランジスタの場合にはコレクタ・エミッタ回路）の一端］が電流制限用抵抗器Ｒ5を通して点火電源コイル２の一方の端子２ａに接続されるとともに他端（主電流が流れる回路の他端）が電流検出用抵抗器Ｒ1を通して点火電源コイル２の他方の端子に接続されたオンオフ制御が可能なスイッチであれば良い。
【００６６】
本明細書では、主電流が流れる端子と制御端子とを有する半導体スイッチを用いる場合、該半導体スイッチの主電流が流れる回路の一端及び他端をそれぞれスイッチの一端及び他端と呼んでいる。例えば、トランジスタをスイッチとして用いる場合には、上記のように、トランジスタのコレクタ・エミッタ回路の一端及び他端をそれぞれスイッチの一端及び他端と呼ぶ。
【００６７】
図３に示した点火装置においては、遮断制御回路が、主電流制御用スイッチ６と点火電源コイル２の他方の端子２ｂとの間に挿入されて主電流制御用スイッチ６に対して直列に接続された電流検出用抵抗器Ｒ1と、点火電源コイル２の一方の端子２ａに一端が接続された電流制限用抵抗器Ｒ5と、電流制限用抵抗器Ｒ5の他端にエミッタが接続され、コレクタが電流検出用抵抗器Ｒ1を通して点火電源コイルの他方の端子に接続されたＰＮＰ形のピーク検出用トランジスタＴＲ4´と、点火電源コイル２の他方の端子２ｂとピーク検出用トランジスタＴＲ4´のベースとの間に電流制限素子Ｒ6を通して接続されたピーク検出用コンデンサＣ1と、ピーク検出用トランジスタのベースと点火電源コイル２の一方の端子２ａとの間にカソードを点火電源コイルの一方の端子２ａ側に向けて接続されたコンデンサ放電用ダイオードＤ2と、電流制限用抵抗器Ｒ5の他端と点火電源コイル２の他方の端子２ｂとの間の電圧を検出する電圧検出回路７と、電圧検出回路７が検出した電圧が設定値以上になったときに導通状態になって主電流制御用スイッチ６への駆動信号の供給を阻止する遮断制御用スイッチ９とにより構成されている。
【００６８】
また上記の各実施形態では、点火コイル１を磁石発電機の固定子側に設けて、該点火コイルの一次コイル２を点火電源コイルとして共用するようにしているが、点火コイルを磁石発電機の外部に配置して、点火コイルとは別個に磁石発電機内に点火電源コイルを設ける場合にも本発明を適用することができる。
【００６９】
この場合には、図４に示したように、点火コイル２と別個に設けた点火電源コイル１０を点火コイルの一次コイル２に対して並列に接続して、該点火電源コイル１０に対して並列に主電流制御用スイッチ６を接続するようにすればよい。この場合遮断制御回路の構成は前記の各実施形態と同様でよい。図４に示した例では、図２に示した実施形態で用いたものと同様の構成を有する遮断制御回路を用いている。
【００７０】
図１に示した実施形態においては、トランジスタＴＲ2及びＴＲ3により、サイリスタと同じ動作をする遮断制御用スイッチを構成しているが、この遮断制御用スイッチは、電圧検出回路７が検出した電圧が設定値以上になったときに動作して主電流制御用スイッチへの駆動信号の供給を阻止するスイッチであれば良く、図示の構成のスイッチに限定されない。例えば、図１において、トランジスタＴＲ2を省略して、トランジスタＴＲ3のみを遮断制御用スイッチとして用い、トランジスタＴＲ3のコレクタを抵抗Ｒ3とダイオードＤ1との接続点に接続するようにしてもよい。この場合は、電圧検出回路７が検出した電圧が設定値以上になったときに遮断制御用スイッチを構成するトランジスタＴＲ3が導通状態になって主電流制御用トランジスタＴＲ1のベース電流（主電流制御用スイッチへの駆動信号）を該トランジスタＴＲ1から側路することによりトランジスタＴＲ1を遮断状態にする。
【００７１】
【発明の効果】
以上のように、本発明によれば、点火電源コイルを短絡したときに流れる電流を検出する電流検出器を設けて、点火電源コイルの一方の半波の出力電圧がピークに達するタイミング及び電流検出器により検出された電流が設定値に達するタイミングのうちの早いほうのタイミングを検出した時に主電流制御用スイッチを遮断状態にするように構成したので、点火電源コイルの誘起電圧が低く、電流検出器により検出される電流が設定値に達しない機関の始動時及び低速回転時には、短絡電流がピークに達したときに該電流を遮断して点火動作を行わせることができ、機関の始動時及び低速回転時に電流の遮断値が不足して点火性能が低下するのを防ぐことができる。
【００７２】
また機関の高速回転時には、短絡電流が設定された値に達した時に該電流を遮断して点火動作を行わせることができるため、電流の遮断値をほぼ一定にしてほぼ一定の点火用高電圧を得ることができ、点火プラグの過度の消耗を防ぎつつ点火動作を安定に行わせることができる。
【００７３】
更に機関の高速回転時には、点火用電源コイルの誘起電圧の波高値の上昇に伴って、短絡電流が遮断値に達する位相を進ませることができるため、点火時期を進角させることができる。
【図面の簡単な説明】
【図１】本発明の第１の実施形態の構成を示した回路図である。
【図２】本発明の第２の実施形態の構成を示した回路図である。
【図３】本発明の第３の実施形態の構成を示した回路図である。
【図４】本発明の第４の実施形態の構成を示した回路図である。
【符号の説明】
１…点火コイル、２…点火電源コイル（点火コイルの一次コイル）、６…主電流制御用スイッチ、７…電圧検出回路、８…ピーク検出用スイッチ、９…遮断制御用スイッチ、ＴＲ1…主電流制御用トランジスタ、ＴＲ4，ＴＲ4´…ピーク検出用トランジスタ、Ｃ1…ピーク検出用コンデンサ、Ｄ2…コンデンサ放電用ダイオード、Ｒ1…電流検出用抵抗器、Ｒ5…電流制限用抵抗器、Ｒ6…電流制限素子。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a current interrupting type ignition device for an internal combustion engine.
[0002]
[Prior art]
As an ignition device for igniting an internal combustion engine, a current interrupting ignition device is used that generates a high voltage for ignition using an ignition power supply coil provided in a magnet generator driven by the internal combustion engine as a power source.
[0003]
For example, as disclosed in Patent Document 1, this type of ignition device is connected in parallel to an ignition power supply coil, and when the ignition power supply coil generates one half-wave output voltage, the ignition power supply A main current control switch that is turned on when a drive signal is supplied from the coil, and a cut-off control circuit that turns off the main current control switch that is turned on are cut off. Then, the voltage induced in the ignition power supply coil is further boosted by the boosting means to generate a high voltage for ignition.
[0004]
As shown in Patent Document 1, a power transistor is usually used as a main current control switch, and a collector / emitter circuit of the transistor is connected in parallel to both ends of an ignition power supply coil. In this specification, a transistor constituting the main current control switch is referred to as a main current control transistor.
[0005]
The base of the main current control transistor is coupled to the ignition power supply coil through a base current supply resistor, and when the ignition power supply coil generates one half-wave output voltage, the main current control transistor is connected to the main current control resistor through the base current supply resistor. A base current is applied to the current control transistor, and the transistor becomes conductive.
[0006]
The cutoff control circuit for shutting down the main current control transistor is detected through a resistance voltage dividing circuit that divides and detects the voltage across the collector / emitter circuit of the main current control transistor and the resistance voltage dividing circuit. It is constituted by a cutoff control switch provided so as to be in a conductive state when the voltage becomes equal to or higher than a set value and to bypass the base current supplied to the main current control transistor from the transistor. As the cutoff control switch, as disclosed in Patent Document 1, a transistor may be used, and a thyristor may be used instead of the transistor.
[0007]
Usually, an ignition coil is used as boosting means for boosting a voltage induced when the current flowing through the ignition power supply coil is cut off. Although the ignition coil may be provided separately from the ignition power supply coil, in this type of ignition device, as disclosed in Patent Document 1, the primary coil of the ignition coil is used as a stator core of a magnet generator. In many cases, the primary coil of the ignition coil is also used as an ignition power supply coil by being wound around and configured to induce an AC voltage in the primary coil of the ignition coil in synchronization with the rotation of the engine.
[0008]
In the ignition device configured as described above, when the ignition power supply coil generates one half-wave output voltage, a base current is applied to the main current control transistor, and the transistor becomes conductive. As a result, the ignition power supply coil is substantially short-circuited through the collector / emitter circuit of the main current control transistor, and a short-circuit current flows from the ignition power supply coil through the collector / emitter circuit of the main current control transistor.
[0009]
This short-circuit current increases as the instantaneous value of the half-wave output voltage generated by the ignition power supply coil increases, and the voltage between the collector and emitter of the main current control transistor increases as the short-circuit current increases. As the voltage rises, the voltage detected through the resistance voltage dividing circuit of the cutoff control circuit also rises.
[0010]
When the voltage detected through the resistance voltage divider circuit reaches a set value, the cutoff control switch is turned on to bypass the base current of the main control transistor from the transistor, so that the main control transistor is cut off. As a result, the short-circuit current that has flowed through the ignition power supply coil is interrupted, and thus a high-polarity voltage is induced in the ignition power supply coil so as to continue to flow the current that has been flowing so far. The voltage is boosted to generate a high voltage for ignition. Since this high voltage for ignition is applied to a spark plug attached to the cylinder of the engine, spark discharge occurs in the spark plug, and the engine is ignited.
[0011]
In the current interrupting type ignition device, it is preferable to make the current interrupting value almost constant in order to eliminate variations in the ignition performance of each product, but the relationship between the collector current magnitude of the transistor and the collector-emitter voltage Is not constant and fluctuates under the influence of the hfe of the transistor. As described above, the collector current (short-circuit current of the ignition power supply coil) is indirectly detected by the voltage between the collector and emitter of the main current control transistor. Thus, when the timing for interrupting the current flowing through the ignition power supply coil is determined, it is inevitable that variations in ignition performance occur due to variations in the current interrupt value for each product. In order to reduce the variation in the ignition performance of each product, after assembling the circuit, finely adjust the resistance value of the resistor that supplies the base current to the main current control transistor, or adjust the voltage between the collector and emitter of the transistor. Since it was necessary to finely adjust the resistance value of the resistor constituting the resistance voltage dividing circuit to be detected, it was inevitable that the manufacturing cost would increase.
[0012]
As shown in Patent Document 2, in order to make the current interruption value as large as possible, a proposal has been made to always interrupt the current at a position where the output voltage of the ignition power supply coil reaches a peak. In the ignition device disclosed in Patent Document 2, a capacitor is connected in parallel through the collector / emitter circuit of a peak detection transistor between the output terminals of a resistance voltage dividing circuit that detects the voltage between the collector and emitter of the main current control transistor. And a circuit for providing a base current to the peak detection transistor through a main current control transistor.
[0013]
In the ignition device disclosed in Patent Document 2, when the ignition power supply coil generates one half-wave output voltage, the main current control transistor is turned on, and at the same time, the peak detection transistor is turned on so that the resistance voltage dividing circuit is turned on. Reduce the voltage between the output terminals. The peak detection transistor maintains a conductive state until one half-wave output voltage generated by the ignition power supply coil reaches the peak, so that the one half-wave output voltage reaches the peak. During this time, the output voltage of the resistance voltage dividing circuit does not reach a level at which the shut-off control switch is turned on. When the half-wave output voltage of one half of the ignition power supply coil reaches the peak, the peak detection transistor is turned off, so that the output voltage of the resistance voltage divider reaches the set value and the cutoff control switch is turned on. The current control transistor is turned off.
[0014]
In the ignition device shown in Patent Document 2, in order to perform the ignition operation by shutting off the main current control transistor at the position where the output voltage of one half wave of the ignition power supply coil reaches the peak as described above. A high ignition high voltage can be obtained by maximizing the current cutoff value.
[0015]
A battery-type current interrupting ignition device that obtains a high voltage for ignition by interrupting the primary current flowing from the battery through the primary coil of the ignition coil and the primary current control switch without using the ignition power supply coil. In Patent Document 3, as shown in Patent Document 3, a current detection resistor for detecting a primary current of an ignition coil and a primary current control switch for maintaining a primary current detected by the resistor are fixed. It is known to provide a current control circuit for controlling a transistor to be configured to control the current cutoff value to be always constant.
[0016]
[Patent Document 1]
Japanese Utility Model Publication No. 54-58524
[0017]
[Patent Document 2]
JP-A-56-101066
[0018]
[Patent Document 3]
JP-A-4-334765
[0019]
[Problems to be solved by the invention]
As described above, in the conventional current interruption type ignition device, the short circuit current of the ignition power supply coil is indirectly detected from the voltage across the main current control switch, and the ignition timing is determined based on the detected value. Therefore, there is a problem that it is difficult to reduce the variation in the ignition performance of each product by reducing the variation in the cutoff value of the current.
[0020]
Also, as disclosed in Patent Document 2, when the ignition operation is always performed at the peak of the output voltage of the ignition power supply coil, the current cutoff value is maximized and the peak value of the ignition high voltage is increased. However, in such a configuration, the ignition timing is always almost constant, so that there is a problem that the ignition timing cannot be advanced in order to improve the performance at high speed rotation of the engine. It was. Further, in the case of such a configuration, there is a possibility that the current cutoff value becomes too large at the time of high-speed rotation of the engine, the ignition high voltage becomes too high, and the life of the spark plug is shortened.
[0021]
In the battery-type current interrupting ignition device, as shown in Patent Document 3, by providing a current control circuit for feedback control of the primary current, the current interrupting value can be set from the start of the engine to the time of high speed rotation. Although it can be kept constant, a current interrupt type ignition device that performs ignition operation using a power coil for ignition provided in a generator driven by an engine as a power source without using a battery, the ignition power source at the start of the engine Since a sufficient voltage cannot be generated from the coil, it is not possible to provide a current control circuit as shown in Patent Document 3 to perform control to keep the current cutoff value constant. In a current interrupt type ignition device that emphasizes simplification of configuration and cost reduction, it is preferable to avoid providing a control circuit for feedback control of current.
[0022]
The object of the present invention is to make it possible to make the current cutoff value at high speed rotation almost constant without adjustment, and to reduce variations in ignition performance without expensive electronic parts and troublesome adjustment work. An object of the present invention is to provide an ignition device for a current interrupting internal combustion engine that can advance the ignition timing as the rotational speed of the engine increases.
[0023]
[Means for Solving the Problems]
The present invention has one half-wave output voltage that has a pair of terminals and the polarity of one terminal is higher than the potential of the other terminal, and the opposite polarity of the one half-wave output voltage. An ignition power coil that generates an AC voltage composed of the other half-wave output voltage in synchronization with the rotation of the internal combustion engine, and an ignition power coil that is connected in parallel to the ignition power coil and that has one half-wave output voltage Main current control switch that is turned on when a drive signal is applied from the ignition power supply coil, a cut-off control circuit that turns off the main current control switch that is turned on, and a main current control switch The present invention is applied to an ignition device for a current interrupting internal combustion engine that includes boosting means for boosting a voltage induced in an ignition power supply coil when generating a high voltage for ignition.
[0024]
In the present invention, the cutoff control circuit includes a current detector that detects a current flowing through the main current control switch, and the timing at which the output voltage of one half wave of the ignition power supply coil reaches the peak and the current detector The main current control switch is configured to be cut off when the earlier one of the timings at which the detected current reaches the set value is detected.
[0025]
As described above, by providing a current detector that detects the current that flows when the ignition power supply coil is short-circuited, the timing at which the output voltage of one half wave of the ignition power supply coil reaches the peak and the current detected by the current detector If the main current control switch is turned off when the earlier of the timings at which the value reaches the set value is detected, a short circuit occurs at the start of the engine where the induced voltage of the ignition power coil is low and at low speed rotation. Since the ignition operation can be performed by interrupting the current when the current reaches the peak, it is possible to prevent the ignition performance from being deteriorated due to insufficient current cutoff value at the time of engine start and low speed rotation. it can.
[0026]
Also, during high-speed rotation of the engine, when the short-circuit current reaches a set value, the current can be cut off and the ignition operation can be performed, so that the current cut-off value is made almost constant and the ignition high voltage is almost constant. Thus, the ignition operation can be stably performed while preventing excessive wear of the spark plug.
[0027]
Further, at the time of high-speed rotation of the engine, the phase at which the short-circuit current reaches the cutoff value advances as the peak value of the induced voltage of the ignition power supply coil increases, so that the ignition timing can be advanced.
[0028]
In a preferred aspect of the present invention, the cutoff control circuit includes a current detection resistor connected in series to the main current control switch on the other terminal side of the ignition power supply coil, and one terminal of the ignition power supply coil. A current limiting resistor with one end connected and one end connected to one terminal of the ignition power supply coil through the current limiting resistor and the other end connected to the other terminal of the ignition power supply coil through the current detection resistor And the drive signal from the ignition power supply coil to the peak detection switch from when the ignition power supply coil generates one half-wave output voltage until the one half-wave output voltage reaches the peak. To detect the voltage between the peak detection switch drive circuit that keeps the peak detection switch conductive and the other end of the current limiting resistor and the other terminal of the ignition power supply coil. And a voltage detection circuit that operates when the voltage detected by the voltage detection circuit exceeds a set value, and prevents the drive signal from being supplied to the main current control switch to turn off the main current control switch. It is comprised with the switch for interruption | blocking control.
[0029]
With the above configuration, when the rotation speed of the internal combustion engine is less than the advance start rotation speed, the voltage detected by the voltage detection circuit at the timing when the output voltage of one half wave of the ignition power supply coil reaches the peak is equal to or higher than the set value. When the rotational speed of the internal combustion engine becomes equal to or higher than the advance start rotational speed, the voltage detected by the voltage detection circuit at a timing before the timing at which one half-wave output voltage of the ignition power supply coil reaches the peak is By setting the circuit constant of the cutoff control circuit (resistance value of the current detection resistor) so that it exceeds the set value, the ignition operation is performed at the timing when the short-circuit current becomes maximum when starting the engine, and sufficient ignition Performance can be obtained, and a stable ignition operation can be performed by keeping the current cutoff value substantially constant during high-speed rotation of the engine.
[0030]
Also, when the engine rotates at high speed, the timing at which the voltage detected by the voltage detection circuit reaches the set value is advanced as the peak value of the output voltage of the ignition power supply coil increases. Thus, the characteristic of advancing the ignition timing can be obtained.
[0031]
In the main current control switch, the collector / emitter circuit is connected in parallel to the ignition power coil with one end of the collector / emitter circuit connected to one terminal of the ignition power coil. When a half-wave output voltage of the polarity is generated, a base current is applied from the ignition power supply coil side, and the main current control transistor is turned on.
[0032]
In this case, the cutoff control circuit includes a current detection resistor inserted between the main current control switch and the other terminal of the ignition power supply coil and connected in series with the main current control switch, and the ignition power supply coil. A current limiting resistor having one end connected to one of the terminals, a collector connected to the other end of the current limiting resistor, and an emitter connected to the other terminal of the ignition power coil through the current detecting resistor NPN type peak detection transistor, a peak detection capacitor connected through a current limiting element between one terminal of the ignition power supply coil and the base of the peak detection transistor, a base of the peak detection transistor and the ignition power supply coil A capacitor discharging diode having an anode connected to the other terminal side of the ignition power source coil toward the other terminal side of the ignition power supply coil, and a current limiting resistor A voltage detection circuit for detecting a voltage between the other end and the other terminal of the ignition power supply coil, and when the voltage detected by the voltage detection circuit becomes equal to or higher than a set value, the conductive state is established and the switch for main current control And a cut-off control switch for blocking the supply of the drive signal.
[0033]
The shut-off control circuit includes a current detection resistor inserted between the main current control switch and the other terminal of the ignition power supply coil and connected in series to the main current control switch, and the ignition power supply coil A current limiting resistor having one end connected to one of the terminals, an emitter connected to the other end of the current limiting resistor, and a collector connected to the other terminal of the ignition power supply coil through the current detecting resistor A PNP type peak detection transistor, a peak detection capacitor connected through a current limiting element between the other terminal of the ignition power supply coil and the base of the peak detection transistor, a base of the peak detection transistor, and an ignition power supply coil A capacitor discharging diode, the cathode of which is connected to one terminal side of the ignition power source coil toward one terminal side of the ignition power supply coil, and a current limiting resistor A voltage detection circuit for detecting a voltage between the other end and the other terminal of the ignition power supply coil, and when the voltage detected by the voltage detection circuit becomes equal to or higher than a set value, the conductive state is established and the switch for main current control It is also possible to adopt a configuration including a cutoff control switch that blocks supply of the drive signal.
[0034]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0035]
FIG. 1 shows the structure of one cylinder according to the first embodiment of the present invention. In FIG. 1, reference numeral 1 denotes ignition as a boosting means having a primary coil 2 and a secondary coil 3 that also serve as an ignition power supply coil. It is a coil. The primary coil 2 and the secondary coil 3 of the ignition coil are wound around a stator core 4 of a magnet generator driven by an internal combustion engine (not shown). The primary coil (ignition power supply coil) 2 has a pair of terminals 2a and 2b at both ends thereof, and one half-wave having a polarity in which the potential of one terminal 2a is higher than the potential of the other terminal 2b. An AC voltage composed of the voltage V1 and the other half-wave voltage V2 having the opposite polarity to the voltage V1 is generated in synchronization with the rotation of the engine. One end of the primary coil 2 of the ignition coil is grounded together with one end of the secondary coil 3 through the iron core 4, and the other end of the secondary coil 3 is connected to a non-grounded terminal of a spark plug 5 attached to a cylinder of the internal combustion engine. Connected through.
[0036]
One terminal 2a of the ignition power supply coil 2 is connected to the collector of a main current control transistor TR1 composed of a Darlington-connected NPN type composite transistor. The emitter of the transistor TR1 and the other terminal 2b of the ignition power supply coil 2 are connected. Is connected to the resistor R1 for current detection.
[0037]
One end of a resistor R2 is connected to the base of the transistor TR1, a resistor R3 is connected between the collector of the transistor and the other end of the resistor R2, and the other end of the resistor R2 and the other terminal of the ignition power supply coil. A diode D1 having an anode directed to the other terminal side of the ignition power supply coil is connected to 2b.
[0038]
In this example, the transistor TR1 is connected in parallel to the ignition power supply coil, and when the ignition power supply coil generates one half-wave output voltage, a drive signal is given from the ignition power supply coil to be in a conductive state. A main current control switch 6 is constructed, and when the ignition power supply coil 2 generates one half-wave voltage V1 by the resistors R3 and R2, a drive signal (the switch) is sent from the ignition power supply coil to the main current control switch 6. The main current control switch driving circuit is configured to provide a signal for turning on the signal.
[0039]
Naturally, the resistance value of the current detection resistor R1 is set to be sufficiently small so as not to adversely affect the ignition operation.
[0040]
The other end of the resistor R2 is connected to the emitter of the PNP transistor TR2, and the resistor R4 is connected between the collector of the transistor TR2 and the other terminal 2b of the ignition power supply coil. The collector and base of an NPN transistor TR3 are connected to the base and collector of the transistor TR2, respectively, and the transistors TR2 and TR3 constitute a switch that functions in the same way as a thyristor.
[0041]
One terminal 2a of the ignition power supply coil 2a is connected to one end of a current limiting resistor R5 having a sufficiently large resistance value, and the other end of the resistor R5 is connected to the collector of an NPN type peak detecting transistor TR4. ing. The emitter of the transistor TR4 is commonly connected to the emitter of the main current control transistor TR1, and is connected to the other terminal 2b of the ignition power supply coil 2 through the current detection resistor R1.
[0042]
A peak detecting capacitor C1 is connected between the base of the peak detecting transistor TR4 and one terminal 2a of the ignition power supply coil 2 through a resistor R6 as a current limiting element, and the other of the base of the transistor TR4 and the other of the ignition power supply coil 2 is connected. A capacitor discharging diode D2 having an anode directed to the other terminal 2b side of the ignition power supply coil 2 is connected between the terminal 2b and the other terminal 2b.
[0043]
One end of a series circuit of resistors R7 and R8 is connected to the collector of the transistor TR4, and the cathode is connected between the other end of the series circuit of resistors R7 and R8 and the other terminal of the ignition power supply coil 2. A diode D3 directed to the other terminal 2b side of the coil is connected. In this example, the resistors R7 and R8 and the diode D3 constitute a voltage detection circuit 7 for detecting the voltage between the other end of the current limiting resistor R6 and the other terminal 2b of the ignition power supply coil 2. Yes.
[0044]
In the example shown in FIG. 1, one end of the peak detecting transistor TR4 is connected to one terminal 2a of the ignition power supply coil through the current limiting resistor R5 and the other end is connected to the ignition power supply coil through the current detecting resistor R1. The peak detection switch 8 connected to the other terminal 2b is configured.
[0045]
Also, the resistor R6, the peak detection capacitor C1, and the diode D2 cause the ignition power supply coil to generate one half-wave output voltage V1 until the one half-wave output voltage reaches the peak. A peak detection switch drive circuit is configured to provide a drive signal from the coil 2 to the peak detection switch and hold the peak detection switch in a conductive state.
[0046]
Further, the transistors TR2 and TR3 are turned on when the voltage detected by the voltage detection circuit 7 exceeds a set value, and the drive signal (base current) is supplied to the main current control switch (main current control transistor TR1) 6. ) Is cut off and the switch 6 is cut off to make the switch 6 in a cut-off state.
[0047]
In the ignition device shown in FIG. 1, a current detection switch inserted between the main current control switch 6 and the other terminal 2 b of the ignition power supply coil 2 and connected in series to the main current control switch 6. A resistor R1, a current limiting resistor R6 having one end connected to one terminal 2a of the ignition power supply coil 2, a collector connected to the other end of the current limiting resistor R6, and an emitter serving as a current detecting resistor An NPN type peak detection transistor TR4 connected to the other terminal of the ignition power supply coil through R1, and a current limiting element R6 connected between one terminal 2a of the ignition power supply coil 2 and the base of the peak detection transistor TR4 The anode is connected between the peak detecting capacitor C1, the base of the peak detecting transistor TR4 and the other terminal 2b of the ignition power supply coil 2, and the other end of the ignition power supply coil 2. A capacitor discharging diode D2 connected to the side, a voltage detecting circuit 7 for detecting a voltage between the other end of the current limiting resistor R6 and the other terminal of the ignition power supply coil, and a voltage detecting circuit 7 One half-wave of the ignition power supply coil 2 is turned on by a cutoff control switch 9 that becomes conductive when the detected voltage exceeds a set value and blocks supply of a drive signal to the main current control switch 6. For main current control when the earlier timing of the timing at which the output voltage V1 reaches the peak and the timing at which the current detected by the current detector (current detection resistor R1 in the illustrated example) reaches the set value is detected. A shut-off control circuit for turning off the switch 6 is configured.
[0048]
The operation of the ignition device shown in FIG. 1 is as follows. When the ignition power supply coil 2 generates an alternating voltage as the crankshaft of the internal combustion engine rotates, the base current is supplied to the main current control transistor TR1 through the resistor R3 and the resistor R2 due to one half-wave voltage V1. Therefore, the transistor TR1 (main current control switch) is turned on. As a result, the ignition power supply coil 2 is substantially short-circuited, and a short-circuit current flows from the ignition power supply coil 2 through the collector / emitter circuit of the transistor TR1 and the current detection resistor R1.
[0049]
When the ignition power supply coil generates one half-wave output voltage V1, a base current is applied to the peak detecting transistor TR4 through the resistor R6 and the peak detecting capacitor C1. As a result, the peak detection transistor TR4 becomes conductive, and the voltage applied to both ends of the voltage detection circuit 7 composed of the resistors R7 and R8 and the diode D3 is changed between the voltage across the current detection resistor R1 and the transistor TR4. Is equal to the voltage of the sum of the collector-emitter voltages.
[0050]
The voltage applied across the voltage detection circuit 7 through the collector / emitter circuit of the transistor TR4 when the transistor TR4 is in conduction corresponds to the voltage across the current detection resistor R1, and this voltage is the main voltage. This corresponds to the short-circuit current flowing through the current control transistor TR1. The short-circuit current increases as the instantaneous value of the voltage induced in the ignition power supply coil 2 increases, so that the voltage applied to the voltage detection circuit 7 increases. A voltage obtained by dividing the sum of the voltage at both ends of the current detection resistor R1 and the voltage between the collector and emitter of the transistor TR4 by the resistors R7 and R8 is a set value (a cutoff control switch comprising transistors TR2 and TR3). Therefore, the cutoff control switch 9 is not driven until the voltage V1 generated by the ignition power supply coil reaches the peak.
[0051]
When the half-wave output voltage V1 generated by the ignition power supply coil 2 reaches a peak, charging of the peak detection capacitor C1 stops, so that the base current that has been flowing to the peak detection transistor TR4 flows until then. The transistor TR4 constituting the peak detection switch is cut off.
[0052]
When the peak detection transistor TR4 enters the cut-off state, the voltage applied to the voltage detection circuit 7 increases, so that the voltage detected by the voltage detection circuit 7 (the voltage across the resistor R8) reaches the set value, The shutoff control switch 9 becomes conductive. As a result, the main current control transistor TR1 is cut off, and a high-polarity voltage is induced in the ignition power supply coil 2 so as to continue to flow the short-circuit current that has been flowing so far. Since this voltage is boosted by the ignition coil 1 as a boosting means, a high voltage for ignition is induced in the secondary coil 3, and the high voltage is applied to the spark plug 5 to perform an ignition operation.
[0053]
When the ignition power supply coil 2 generates the other half-wave output voltage V2, the charge of the peak detection capacitor C1 is discharged through the resistor R6, the ignition power supply coil 2 and the diode D2, and then the capacitor C1 is charged in the reverse direction. The
[0054]
Thus, at the time of engine start and low speed rotation, when the half-wave output voltage V1 generated by the ignition power supply coil 2 reaches the peak, the main current control transistor TR1 is turned off from the conductive state. An ignition operation is performed.
[0055]
On the other hand, during high-speed rotation of the engine, after the ignition power supply coil 2 generates one half-wave voltage V1, the peak detection transistor TR4 is in the on state (until the voltage V1 reaches the peak). ), The short-circuit current flowing through the main current control transistor reaches a set cut-off value, and when the short-circuit current reaches a set cut-off value, the voltage across the current detection resistor R1 and the transistor Since the voltage (output voltage of the voltage detection circuit) obtained by dividing the voltage between the collector and emitter of TR4 by the resistors R7 and R8 reaches the set value, the voltage V1 before the timing when it reaches the peak. At the timing, the cut-off control switch 9 is turned on, and the main current control transistor TR1 is turned off.
[0056]
The timing at which the shut-off control switch 9 is turned on (the timing at which the short-circuit current reaches a certain shut-off value through the main current control switch) is the half-wave output voltage V1 of the ignition power supply coil 2 due to the increase in the engine speed. As the peak value increases, the engine ignition timing advances as the engine speed increases.
[0057]
In the ignition device shown in FIG. 1, when the rotational speed of the internal combustion engine is less than the advance start rotational speed, the voltage detection circuit 7 detects the output voltage of one half wave of the ignition power supply coil 2 at the peak. The voltage is detected at a timing before the timing at which the output voltage of one half wave of the ignition power supply coil 2 reaches the peak when the internal combustion engine speed exceeds the set value and the rotational speed of the internal combustion engine exceeds the advance start rotational speed. Set the circuit constants of the cutoff control circuit (such as the resistance value of the current detection resistor R1 and the resistance value of the resistor R7 that constitutes the voltage detection circuit) so that the voltage detected by the circuit 7 is equal to or higher than the set value. As a result, the ignition timing is constant in the rotational speed region below the advance angle start rotational speed, and the ignition timing is advanced as the rotational speed increases in the region higher than the advance angle start rotational speed. It is possible to obtain the sex.
[0058]
Also, in the region above the advance start rotation speed, the short-circuit current flowing through the main current control transistor TR1 reaches a certain level (cutoff value), and the voltage across the current detection resistor R1 reaches a predetermined level. When the voltage detected by the detection circuit 7 reaches the set value, the current is interrupted and the ignition operation is performed, so that the current cutoff value can be made substantially constant and a substantially constant ignition high voltage can be generated. Thus, a stable ignition operation can be performed while preventing unnecessary consumption of the spark plug.
[0059]
In a conventional current interrupting ignition device in which a short-circuit current is indirectly detected from the collector-emitter voltage of the main current control transistor and the ignition timing is determined based on the detected value, the main current control transistor In order to reduce the variation in ignition characteristics for each product, the main current control is performed after the circuit is assembled. Although it was necessary to finely adjust the resistance value of the circuit that supplies the base current to the transistor for the transistor and the resistance value of the voltage detection circuit that detects the collector-emitter voltage of the transistor by laser trimming or the like, as in the present invention, The short-circuit current flowing through the main current control transistor is directly detected, and the detected value (voltage across the current detection resistor) is at a predetermined level. When so as to cut off the current when it has reached, even without adjusting the resistance value of the resistor constituting the interruption control circuit, it is possible to suppress variation in ignition performance within an allowable range.
[0060]
In the above embodiment, an NPN-type transistor is used as the main current control switch. However, this switch is not limited to a transistor as long as it can be turned on / off.
[0061]
When a transistor is used as the main current control switch, the transistor (main current control transistor) is not limited to the NPN type, but a PNP type main current control transistor is used, The emitter circuit may be connected in parallel to the ignition power supply coil.
[0062]
In the above example, the cutoff control switch 9 is composed of the transistors TR2 and TR3. However, the cutoff control switch 9 is in a conductive state when the voltage detected by the voltage detection circuit 7 exceeds a set value. Therefore, any switch that blocks the supply of the drive signal to the main current control switch 6 may be used, and a switch composed of a switch element other than a transistor can also be used as the cutoff control switch 9. For example, the thyristor Th can be used as the cutoff control switch 9 as in the second embodiment shown in FIG.
[0063]
The ignition device shown in FIG. 2 is configured in the same manner as the ignition device shown in FIG. 1 except that a thyristor Th is used as a cutoff control switch.
[0064]
In the embodiment shown in FIG. 1, the NPN transistor TR4 is used as the peak detection switch 8. However, as in the third embodiment shown in FIG. 3, the PNP transistor TR4 ′ is used to detect the peak. The switch 8 may be configured. In this case, the emitter of the transistor TR4 'is connected to the other end of the current limiting resistor R5, and the collector of the transistor TR4' is connected to the other terminal 2b of the ignition power supply coil 2 through the current detecting resistor R1. A peak detecting capacitor C1 is connected through a resistor R6 between the base of the transistor TR4 'and the other terminal 2b of the ignition power supply coil, and between the base of the transistor TR4 and one terminal 2a of the ignition power supply coil 2. A capacitor discharging diode D2 is connected.
[0065]
Note that the peak detection switch 8 is not limited to a transistor, and one end thereof [one end of a circuit through which a main current flows (a collector / emitter circuit in the case of a transistor)] is connected to an ignition power supply coil through a current limiting resistor R5. 2 is a switch capable of on / off control, connected to one terminal 2a of 2 and having the other end (the other end of the circuit through which the main current flows) connected to the other terminal of the ignition power supply coil 2 through the current detection resistor R1. I need it.
[0066]
In this specification, when a semiconductor switch having a terminal through which a main current flows and a control terminal is used, one end and the other end of the circuit through which the main current flows are called one end and the other end of the switch, respectively. For example, when a transistor is used as a switch, as described above, one end and the other end of the collector / emitter circuit of the transistor are referred to as one end and the other end of the switch, respectively.
[0067]
In the ignition device shown in FIG. 3, the cutoff control circuit is inserted between the main current control switch 6 and the other terminal 2 b of the ignition power supply coil 2 and connected in series to the main current control switch 6. The current detecting resistor R1, the current limiting resistor R5 having one end connected to one terminal 2a of the ignition power supply coil 2, the emitter connected to the other end of the current limiting resistor R5, and the collector Between the other terminal 2b of the ignition power supply coil 2 and the base of the peak detection transistor TR4 'connected to the other terminal of the ignition power supply coil through the current detection resistor R1 Between the base of the peak detection transistor C1 connected through the current limiting element R6 and the base of the peak detection transistor and one terminal 2a of the ignition power supply coil 2 to the ignition power supply coil. Detection circuit 7 for detecting a voltage between the capacitor discharging diode D2 connected to the one terminal 2a side of the first terminal 2a, the other end of the current limiting resistor R5 and the other terminal 2b of the ignition power supply coil 2. And a cut-off control switch 9 that becomes conductive when the voltage detected by the voltage detection circuit 7 exceeds a set value and blocks supply of a drive signal to the main current control switch 6. .
[0068]
In each of the above embodiments, the ignition coil 1 is provided on the stator side of the magnet generator, and the primary coil 2 of the ignition coil is shared as the ignition power supply coil. The present invention can also be applied to the case where an ignition power supply coil is provided outside the ignition coil in a magnet generator separately from the ignition coil.
[0069]
In this case, as shown in FIG. 4, an ignition power supply coil 10 provided separately from the ignition coil 2 is connected in parallel to the primary coil 2 of the ignition coil and is parallel to the ignition power supply coil 10. The main current control switch 6 may be connected to the power source. In this case, the configuration of the cutoff control circuit may be the same as that in each of the above embodiments. In the example shown in FIG. 4, a cutoff control circuit having the same configuration as that used in the embodiment shown in FIG. 2 is used.
[0070]
In the embodiment shown in FIG. 1, the transistors TR2 and TR3 constitute a cutoff control switch that performs the same operation as the thyristor. The cutoff control switch is set with a voltage detected by the voltage detection circuit 7. Any switch that operates when the value exceeds the value and blocks the supply of the drive signal to the main current control switch may be used, and the switch is not limited to the illustrated configuration. For example, in FIG. 1, the transistor TR2 may be omitted, and only the transistor TR3 may be used as a cutoff control switch, and the collector of the transistor TR3 may be connected to the connection point between the resistor R3 and the diode D1. In this case, when the voltage detected by the voltage detection circuit 7 becomes equal to or higher than the set value, the transistor TR3 constituting the cutoff control switch becomes conductive and the base current of the main current control transistor TR1 (main current control The transistor TR1 is cut off by bypassing the drive signal to the switch from the transistor TR1.
[0071]
【The invention's effect】
As described above, according to the present invention, the current detector that detects the current that flows when the ignition power supply coil is short-circuited is provided, and the timing and current detection when the output voltage of one half-wave of the ignition power supply coil reaches the peak. Since the main current control switch is turned off when the earlier one of the timings when the current detected by the detector reaches the set value is detected, the induced voltage of the ignition power coil is low and the current detection When starting the engine where the current detected by the detector does not reach the set value and during low speed rotation, when the short-circuit current reaches the peak, the current can be cut off and the ignition operation can be performed. It is possible to prevent the ignition performance from deteriorating due to insufficient current cutoff value during low-speed rotation.
[0072]
Also, during high-speed rotation of the engine, when the short-circuit current reaches a set value, the current can be cut off and the ignition operation can be performed, so that the current cut-off value is made almost constant and the ignition high voltage is almost constant. Thus, the ignition operation can be stably performed while preventing excessive wear of the spark plug.
[0073]
Further, when the engine rotates at high speed, the phase at which the short-circuit current reaches the cutoff value can be advanced as the peak value of the induced voltage of the ignition power supply coil increases, so that the ignition timing can be advanced.
[Brief description of the drawings]
FIG. 1 is a circuit diagram showing a configuration of a first exemplary embodiment of the present invention.
FIG. 2 is a circuit diagram showing a configuration of a second exemplary embodiment of the present invention.
FIG. 3 is a circuit diagram showing a configuration of a third exemplary embodiment of the present invention.
FIG. 4 is a circuit diagram showing a configuration of a fourth embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Ignition coil, 2 ... Ignition power supply coil (primary coil of ignition coil), 6 ... Main current control switch, 7 ... Voltage detection circuit, 8 ... Peak detection switch, 9 ... Shut-off control switch, TR1 ... Main current Control transistor, TR4, TR4 '... peak detection transistor, C1 ... peak detection capacitor, D2 ... capacitor discharge diode, R1 ... current detection resistor, R5 ... current limiting resistor, R6 ... current limiting element.

Claims

One half-wave output voltage having a pair of terminals and having a polarity in which the potential of one terminal is higher than the potential of the other terminal, and the other half-wave having the opposite polarity to the output voltage of the one half-wave An ignition power supply coil that generates an AC voltage composed of the output voltage of the internal combustion engine in synchronization with the rotation of the internal combustion engine, and is connected in parallel to the ignition power supply coil, and the ignition power supply coil generates one half-wave output voltage. A main current control switch that is turned on when a drive signal is applied from the ignition power supply coil when it occurs, a cut-off control circuit that turns off the main current control switch that is turned on, and the main current control In a current interrupting internal combustion engine ignition device comprising boosting means for boosting a voltage induced in the ignition power supply coil when the switch for shutting off is generated and generating a high voltage for ignition,
The cutoff control circuit includes a current detector that detects a current flowing through the main current control switch, and is detected by the timing when the output voltage of the one half wave of the ignition power supply coil reaches a peak and the current detector. An ignition device for a current cut-off type internal combustion engine, characterized in that the main current control switch is turned off when the earlier of the timings at which the generated current reaches a set value is detected .

One half-wave output voltage having a pair of terminals and having a polarity in which the potential of one terminal is higher than the potential of the other terminal, and the other half-wave having the opposite polarity to the output voltage of the one half-wave An ignition power supply coil that generates an AC voltage composed of the output voltage of the internal combustion engine in synchronization with the rotation of the internal combustion engine, and is connected in parallel to the ignition power supply coil, and the ignition power supply coil generates one half-wave output voltage. A main current control switch that is turned on when a drive signal is applied from the ignition power supply coil when it occurs, a cut-off control circuit that turns off the main current control switch that is turned on, and the main current control In a current interrupting internal combustion engine ignition device comprising boosting means for boosting a voltage induced in the ignition power supply coil when the switch for shutting off is generated and generating a high voltage for ignition,
The shut-off control circuit includes a current detection resistor connected in series to the main current control switch on the other terminal side of the ignition power supply coil, and one end of the one terminal of the ignition power supply coil. A connected current limiting resistor and one end connected to one terminal of the ignition power supply coil through the current limiting resistor and the other end connected to the other terminal of the ignition power supply coil through the current detection resistor A peak detection switch connected to the first power source coil and the first power source coil from the first power source coil until the first power output voltage reaches the peak. A peak detection switch driving circuit for supplying a drive signal to the detection switch to hold the peak detection switch in a conductive state; the other end of the current limiting resistor; A voltage detection circuit for detecting a voltage between the other terminal of the power supply and a drive signal supplied to the main current control switch that operates when the voltage detected by the voltage detection circuit exceeds a set value. A shut-off control switch that shuts off the main current control switch by blocking
An ignition device for a current interrupting internal combustion engine characterized by the above.

One half-wave output voltage having a pair of terminals and having a polarity in which the potential of one terminal is higher than the potential of the other terminal, and the other half-wave having the opposite polarity to the output voltage of the one half-wave An ignition power supply coil that generates an AC voltage composed of the output voltage of the internal combustion engine in synchronization with the rotation of the internal combustion engine, and is connected in parallel to the ignition power supply coil, and the ignition power supply coil generates one half-wave output voltage. A main current control switch that is turned on when a drive signal is applied from the ignition power supply coil when it occurs, a cut-off control circuit that turns off the main current control switch that is turned on, and the main current control In a current interrupting internal combustion engine ignition device comprising boosting means for boosting a voltage induced in the ignition power supply coil when the switch for shutting off is generated and generating a high voltage for ignition,
The main current control switch has a collector / emitter circuit connected in parallel to the ignition power coil with one end of the collector / emitter circuit connected to one terminal of the ignition power coil. When the coil generates a half-wave output voltage of one polarity, a base current is given from the ignition power supply coil side, and the main current control transistor becomes conductive.
The cutoff control circuit includes a current detection resistor inserted between the main current control switch and the other terminal of the ignition power supply coil and connected in series to the main current control switch; A current limiting resistor having one end connected to the one terminal of the ignition power supply coil, a collector connected to the other end of the current limiting resistor, and an emitter passing through the current detection resistor, the other of the ignition power supply coil An NPN-type peak detecting transistor connected to a terminal of the ignition power coil; a peak detecting capacitor connected through a current limiting element between the one terminal of the ignition power supply coil and a base of the peak detecting transistor; An anode is connected between the base of the peak detection transistor and the other terminal of the ignition power supply coil toward the other terminal side of the ignition power supply coil. A capacitor discharging diode, a voltage detecting circuit for detecting a voltage between the other end of the current limiting resistor and the other terminal of the ignition power supply coil, and a voltage detected by the voltage detecting circuit is equal to or higher than a set value. A disconnection control switch that is in a conductive state when it becomes, and prevents the supply of the drive signal to the main current control switch,
An ignition device for a current interrupting internal combustion engine characterized by the above.

One half-wave output voltage having a pair of terminals and having a polarity in which the potential of one terminal is higher than the potential of the other terminal, and the other half-wave having the opposite polarity to the output voltage of the one half-wave An ignition power supply coil that generates an AC voltage composed of the output voltage of the internal combustion engine in synchronization with the rotation of the internal combustion engine, and is connected in parallel to the ignition power supply coil, and the ignition power supply coil generates one half-wave output voltage. A main current control switch that is turned on when a drive signal is applied from the ignition power supply coil when it occurs, a cut-off control circuit that turns off the main current control switch that is turned on, and the main current control In a current interrupting internal combustion engine ignition device comprising boosting means for boosting a voltage induced in the ignition power supply coil when the switch for shutting off is generated and generating a high voltage for ignition,
The main current control switch has a collector / emitter circuit connected in parallel to the ignition power coil with one end of the collector / emitter circuit connected to one terminal of the ignition power coil. When the coil generates a half-wave output voltage of one polarity, a base current is given from the ignition power supply coil side, and the main current control transistor becomes conductive.
The cutoff control circuit includes a current detection resistor inserted between the main current control switch and the other terminal of the ignition power supply coil and connected in series to the main current control switch; A current limiting resistor having one end connected to the one terminal of the ignition power supply coil, an emitter connected to the other end of the current limiting resistor, and a collector passing through the current detection resistor, the other of the ignition power supply coil A PNP-type peak detecting transistor connected to a terminal of the first power source, a peak detecting capacitor connected through a current limiting element between the other terminal of the ignition power supply coil and a base of the peak detecting transistor, A cathode is connected between the base of the peak detection transistor and one terminal of the ignition power supply coil with the one terminal side of the ignition power supply coil facing. A capacitor discharging diode, a voltage detecting circuit for detecting a voltage between the other end of the current limiting resistor and the other terminal of the ignition power supply coil, and a voltage detected by the voltage detecting circuit is equal to or higher than a set value. A disconnection control switch that is in a conductive state when it becomes, and prevents the supply of the drive signal to the main current control switch,
An ignition device for a current interrupting internal combustion engine characterized by the above.