JP3834876B2

JP3834876B2 - Fuel injection timing control device and ignition timing detection device

Info

Publication number: JP3834876B2
Application number: JP17919496A
Authority: JP
Inventors: 賢内山; 昭和小島; 寛原口
Original assignee: Denso Corp
Current assignee: Denso Corp
Priority date: 1996-07-09
Filing date: 1996-07-09
Publication date: 2006-10-18
Anticipated expiration: 2016-07-09
Also published as: JPH1026047A

Description

【０００１】
【発明の属する技術分野】
本発明は、燃料噴射時期を制御する装置、及び着火時期を検出する装置に関するものである。
【０００２】
【従来の技術】
従来ディ−ゼル機関において、燃料の着火時期が目標とする着火時期となるように燃料の噴射時期を制御するものが知れている。この制御を行うためには着火時期を検出する手段が必要であるが、その検出手段の中で振動センサは、機関の加工が不要であり、また安価という点から有利である。
【０００３】
このような燃料噴射時期を振動センサにより制御する技術として例えば特開昭６０−１３８２４７号公報がある。この公報には、圧電素子よりなる振動センサを各気筒の燃料噴射ノズルまたはノズルホルダに設け、振動センサで検出した振動波形に基づいて着火の瞬間を検出し、この検出結果に基づいて得た実着火時期（クランクの基準位置に対する実着火時の位相）とエンジンの運転状態に応じた最適な目標着火時期との偏差を求め、この偏差に応じた出力を噴射時期調節用タイマに与えて燃料噴射時期を制御することが記載されている。
【０００４】
さらにまた特開昭５９−１８５８３７号公報には、各気筒に着火検出器を設けて、着火検出器の検出信号に基づいて得た実着火時期と目標とする着火時期との偏差を求めると共に、４気筒分の偏差の平均値を求め、これを噴射時期の制御信号に反映させる技術が開示されている。この技術は、各気筒とも噴射時期が同じてあっても圧縮比のばらつきや温度分布の違いなどによって着火時期が気筒間でばらつくため、検出した各気筒の着火時期が目標着火時期となるように噴射時期を制御して気筒間での着火時期のばらつきをなくすことを狙いとしている。また着火検出器としては燃焼光を捉えるフォトセンサ、気筒内の圧力を検出する内圧センサ、あるいは振動センサなどを用いることが記載されている。
【０００５】
【発明が解決しようとする課題】
ところで着火検出器としてフォトセンサや内圧センサを用いる場合には、各気筒の筒内に直接挿入され、燃焼光や内圧を直接測定しているため機械振動ノイズの重畳や検出遅れといった要因は含まない。これに対し振動センサを用いた場合には、燃料が爆発したときの気筒の振動を捉えているため、次のような問題がある。
【０００６】
（１）先ず、振動センサを利用するにあたり１つの振動センサにより多気筒例えば４気筒の着火時期を検出するように構成すれば、安価なシステムを構成できる点で有利である。しかしながらこの場合振動センサから遠い気筒については、振動センサに近い気筒に比べて、燃焼振動のレベルが小さいため、燃焼振動以外の機械振動ノイズに弱く、従って振動センサと気筒間の相対位置関係によって、検出される着火時期の信頼度が異なってしまう。またバルブ着座時に機械振動ノイズが発生するので、バルブ開閉のタイミングと燃焼時期とが重なってしまう気筒と重ならない気筒とでは、やはり検出される着火時期の信頼度が異なる。
【０００７】
（２）更に高回転及び／または高負荷運転時は低回転及び／または低負荷運転時よりも機関の振動が大きいので機械振動ノイズが大きくなり、このため振動センサからの電気信号にこのノイズ分が含まれてしまうので、Ｓ／Ｎが悪くなり、着火の瞬間の検出精度つまり検出した実着火時期の信頼度が低下する。また回転数があまり高くない状況においても急加速時などのような過渡時にはやはり機械振動ノイズが大きくなり、同様に信頼度が低下する。
【０００８】
本発明はこのような事情の下になされたものであり、その目的は、簡素で高精度な着火時期制御を、振動センサを用いて実現することのできる装置を提供することにある。
【０００９】
【課題を解決するための手段】
請求項１の発明では、機関の複数の気筒の振動を共通の振動センサ例えば１個の振動センサにより検出し、検出した振動を信号処理回路にて処理し、各気筒内の着火を検出する。この着火検出手段からの着火検出信号に基づいて、実着火時期が求められる。
【００１０】
一方目標着火時期設定手段により運転状態に応じた目標着火時期を求め、この目標着火時期と前記実着火時期との偏差に応じた補正項を補正項演算手段により求める。そして第１の重み係数設定手段により予め気筒毎の第１の重み係数を設定し、重み付け手段にて前記補正項を第１の重み係数により気筒毎に重み付けする。こうして重み付けされた補正項に基づいて噴射時期調節手段を制御する。
【００１１】
請求項１の発明によれば、検出した実着火時期について気筒毎の信頼度の違いを考慮し、例えば各気筒と振動センサとの位置関係に応じた着火時期検出信号の信頼度に応じて、燃料噴射時期制御への前記補正項の寄与の程度に重み付けをしているため、気筒毎に振動センサを設ける場合に比べて安価で、かつ高精度な燃料噴射時期制御を行うことができる。
【００１２】
請求項２の発明では、請求項１の場合と同様に、目標着火時期と実着火時期との偏差に応じた補正項に基づいて噴射時期調節手段を制御するにあたり、運転状態を考慮した重み付けを前記補正項に対して行う。即ち運転状態検出手段により検出した検出信号に基づいて第２の重み係数を設定し、重み付け手段にて前記補正項を第２の重み係数により重み付けする。この重み係数の具体的設定方法としては、例えば請求項４に記載したように、高負荷及び／または高回転ほど重み付けの影響が小さくなるように決められる。
【００１３】
請求項２の発明によれば、振動センサを用いて着火を検出したときの運転状態による機械振動ノイズの影響を考慮して、運転状態に応じた検出着火時期の信頼度の違いを燃料噴射時期制御に反映しているため、高精度な燃料噴射時期制御を行うことができる。また請求項３の発明のように、複数の気筒に対して共通の振動センサを用いる場合に、気筒毎の第１の重み係数と運転状態に応じた第２の重み係数を設定してこれらにより補正項を重み付けすれば、単に気筒毎に重み付けする場合に比べてより一層信頼性の高い燃料噴射時期制御を行うことができる。
【００１４】
更にまた請求項８の着火時期検出装置では、請求項１と同様に振動センサを用いた着火検出手段及び基準位置検出手段により実着火時期を求めると共に、目標着火時期設定手段により目標着火時期を求める。そして第１の重み係数設定手段により予め気筒毎に第１の重み係数を設定し、実着火時期補正手段により前記実着火時期を、目標着火時期及び第１の重み係数により気筒毎に補正し、補正された実着火時期を検出着火時期とする。従って検出した実着火時期について気筒毎の信頼度の違いを考慮して補正しているため、高精度な着火時期検出を行うことができる。
【００１５】
請求項９の着火時期検出装置では、請求項８の発明と同様に実着火時期を目標着火時期及び重み係数により補正するが、この重み係数（第２の重み係数）としては、運転状態検出部からの検出信号に基づいて設定される。従って振動センサを用いて着火を検出したときの運転状態による機械振動ノイズの影響を考慮して実着火時期を補正しているため、高精度な着火時期検出を行うことができる。
【００１６】
【発明の実施の形態】
図１は本発明の実施の形態である燃料噴射時期制御装置の構成要素をブロック化して全体の概略構成を示すブロック図であり、先ず図１を参照しながら本実施の形態の概要を簡単に説明する。運転状態検出手段１０１は、エンジンの回転数検出部２０１、アクセル開度検出部２０２、吸気圧検出部２０３、及び燃料の噴射量検出部２０４などを含む。
【００１７】
目標噴射時期設定手段１０２及び目標着火時期設定手段１０３は、運転状態検出手段１０１からの検出信号に応じて夫々目標噴射時期及び目標着火時期を設定する。実噴射時期演算手段１０４ａは、燃料の噴射の瞬間を検出する噴射時点検出手段１０４とクランクの基準位置を検出する基準位置検出手段１０５との各検出信号に基づいて実噴射時期、即ち基準位置に対する噴射時点のクランク角度（位相）を検出する。
【００１８】
一方着火検出手段１０６は、エンジンの各気筒に対して共通に設けられた１個の振動センサ２０５と信号処理回路２０６とからなり、振動センサ２０５で検出した振動信号を信号処理回路２０６にて処理し、着火の瞬間を検出する。実着火時期演算手段１０７は、着火検出手段１０６及び基準位置検出手段１０５の各検出信号に基づいて実着火時期、即ち基準位置に対する着火の時点のクランク角度（位相）を検出する。補正項演算手段１０８は、目標着火時期と実着火時期との位相差（補正項）を求める。
【００１９】
前記補正項は、重み付け手段１０９により、第１の重み係数及び第２の重み係数が掛け算されることにより重み付けされる。第１の重み係数は、第１の重み係数設定手段１１０により、気筒と振動センサとの位置関係に応じて設定され、また第２の重み係数は、第２の重み係数設定手段１１１により、運転状態検出手段１０１からの検出信号に応じて設定される。そして出力値演算手段１１２では、重みづけされた補正項に基づいて目標噴射時期を補正、例えば目標噴射時期に補正項を加算すると共に、補正後の目標噴射時期と実噴射時期との差分に基づいて、噴射時期調節手段１３３に制御信号を出力する。
【００２０】
次に図１に示した燃料噴射時期制御装置の具体的構成及び作用について詳述する。図２はこの燃料噴射時期制御装置の具体的な全体構成を示す図である。１は例えば直列４気筒ディーゼルエンジン（機関）、２は分配型燃料噴射ポンプであり、燃料噴射ポンプ２から圧送された燃料は燃料噴射ノズル２１を介して各気筒内に噴射される。燃料噴射ポンプ２の噴射時期は、電気−油圧式タイマと呼ばれる後述の噴射時期調節手段３により調節される。
【００２１】
前記ディーゼルエンジン１には、振動センサ４が取り付けられている。この振動センサ４はエンジンブロックの振動を例えば圧電素子により電気信号として検出し、この信号に基づいて着火の瞬間を検出するためのものであり、この例では各気筒の着火を１個の振動センサで検出するようにしている。直列４気筒エンジンに振動センサを取り付ける場合の好ましい例を図３に示すと、この場合振動センサ４は２番目及び３番目の気筒Ｃｙ２、Ｃｙ３の間であって、エンジンブロックＥＢの上端付近が好ましい。Ｃｙ１、Ｃｙ４は気筒、Ｈはヘッドカバー、Ｐはオイルパンである。
【００２２】
またＶ型６気筒エンジンの場合は振動センサ４をバンクの中央に設けることが好ましい。その理由については、振動センサ４の取り付け位置について、各気筒に対してできる限り対象となる位置を選択することにより、特定の気筒で捕捉される燃焼振動が極端に小さくなるのを防ぐためである。
このようにして振動センサ４により検出された振動信号（圧電素子で変換された電気信号）は図４に示す信号処理回路４０に入力される。即ち振動信号は、フィルタ４１に入力され、ここで高周波ノイズや直流成分が除去された後、積分回路４２及びピークホールド回路４３に入力される。各回路４２、４３の出力は、コンパレータ４４の両入力端に夫々入力される。このコンパレータ４４は、ピークホールド回路４３からの出力が積分回路４２からの出力よりも大きくなったときに出力レベル「Ｈ」（例えば５Ｖの信号）レベルとなり、それ以外のときは「Ｌ」（例えば０Ｖの信号）レベルとなるように構成されている。
【００２３】
燃焼振動のレベルが小さくピークホールド回路４３の出力が積分回路４２の出力を越えない場合には、コンパレータの出力電圧は０Ｖのままとなる。ピークホールド回路４３には、エンジン制御用マイコン４５より、リセット信号が入力されるようになっており、このリセット信号はエンジンの圧縮ＴＤＣ後９０゜ＣＡにて出力され、毎燃焼ごとにリセットされる。図４の処理回路の動作の詳細を図５に示す。振動センサ４からの信号をフィルタリングした信号が（ａ）である。対応付けて表わすためにＣｙ１〜Ｃｙ４を付してある。フィルタリング後の信号を積分回路４２に入力して得られる波形は（ｂ）に点線で示すＶｉの様になる。またピークホールド回路４３に入力して得られる波形は（ｂ）に実線で示すＶＰの様になる。この２つの信号（Ｖｉ、ＶＰ）をコンパレータ４４に入力すると、コンパレータ４４の出力端から（ｃ）に示すＶＣが得られる。
【００２４】
前記信号処理回路４０は、図２に示す電子制御ユニット１０内の入力回路１１に相当し、この入力回路１１で得た信号つまり図５に示すコンパレータ４４の出力信号ＶＣはマイクロコンピュータＭＣに入力される。この例では振動センサ４及び信号処理回路４０により着火検出手段が構成されている。
上述のようにして着火の瞬間が検出されるが、この検出信号に基づいてクランクの基準位置に対する着火の時点の位相、つまり着火の時期（実着火時期）次のようにして求められる。図２ではクランクの基準位置を検出する基準位置検出手段である基準位置検出器は符号５で示してあり、この基準位置検出器５からの信号は入力回路１２を介してマイクロコンピュータＭＣに取り込まれる。この基準位置検出器５は、図６に示すようにクランク軸に同期して回転すると共に１個の突起を備えた歯車５１と電磁ピックアップ５２とを備え、上死点後の基準クランク位置で突起が電磁ピックアップ５２に対向し、これにより電磁ピックアップ５２から図７（ａ）に示すような交流信号Ｖａを出力するように構成されている。
【００２５】
そしてこの交流信号は入力回路１２に入力すると波形成形されて図７（ｂ）に示すようなパルス信号Ｖｂとなる。マイクロコンピュータＭＣではこのパルス信号Ｖｂのパルス間隔ｔＭをカウントしてエンジンの回転数を算出する。マイクロコンピュータＭＣでは、クランクの基準位置に対応するパルス信号Ｖｂと着火検出手段からの検出信号であるパルス信号Ｖｃとの時間差を求め、この時間差とエンジンの回転数とに基づいて、基準位置から燃料の着火までに要したクランク角度即ち実着火時期ＴＴＰを算出する。
【００２６】
このように本実施の形態では、図１に示す実着火時期演算部１０７は、マイクロコンピュータＭＣより構成されるが、目標着火時期設定手段１０３、補正項演算手段１０８、目標噴射時期設定手段１０２、第１の重み係数設定手段１１０、第２の重み係数設定手段１１１及び出力値演算手段１１２などもマイクロコンピュータＭＣにより構成され、各処理はソフトウェアにより実行される。
【００２７】
続いてこれら各構成要素について具体的に述べる。先ず目標着火時期設定手段１０３においては、既述のようにして検出したエンジンの回転数ＮＥと燃料の噴射量の検出値（実噴射量）とから、予めメモリ内に格納したマップあるいは計算式により目標着火時期を求める。
燃料噴射量の検出は、図２に示すように噴射ポンプ２に組み合わせて設けられた燃料噴射量検出器６を用いて行われる。この燃料噴射量検出器６の一例を図８に示すと、６１は噴射ポンプのスピルリング、６２はプランジャであり、図示しないフェースカムによりプランジャ６２は回転しながら左右に移動し、燃料を圧送、分配する。検出器６０の可動コア６３はレバーを介してスピルリング６１に一体に固定されており、筒状ボビンの外周に二対のコイル６４が巻かれている。本体は固定ネジ６５にてポンプヘッドに固定されている。
【００２８】
噴射量の検出は、可能動コア６３が二対のコイル６４の中を摺動することでコイル６４のインダクタンスが変化することを利用しており、スピルリング６１は燃料噴射量が少ない場合は図中左方に位置し、燃料噴射量が多く必要な場合には右方に位置するように動く。従って燃料噴射量が多い場合には出力電圧値は低く、例えば１Ｖであり、またアイドル運転状態の場合の様に噴射量が少ない場合にはスピルリング２１は左方に移動し、コア６３のストロークは大きくなり例えば出力電圧は３Ｖとなるように作動する。こうして得られた燃料噴射量の検出信号（アナログ電圧）は図２に示すＡ／Ｄ変換器１３を介してマイクロコンピュータＭＣに取り込まれる。
【００２９】
ここで図２の全体構成図に説明を戻すと、１５はアクセル踏み込み量を検出するアクセル位置検出器、１６はエンジン１の燃料温度を検出する温度検出器であり、これら検出器１５、１６の各検出信号は、前記Ａ／Ｄ変換器１３を介してマイクロコンピュータＭＣに取り込まれる。またマイクロコンピュ−タＭＣの出力側には、後述の噴射時期調節手段３に適当なデュ−ティ比をもつパルス信号を与えるための出力回路１７が設けられている。
【００３０】
また燃料の噴射時期の検出は、図２に示すように噴射ポンプ２に付設された噴射時期検出器７を用いて行われる。この噴射時期検出器７の一例を図９に示すと、１８０度間隔で設けられた２個の突起７１、７１を有する歯車７２は噴射ポンプ２の駆動軸７３に取り付けられている。前記突起７１、７１を検出する電磁ピックアップ７４はローラリング７５に取り付けられており、噴射時期を変更すると、ローラリング７５と共に電磁ピックアップ７４も駆動軸７３のまわりに回動し、発生する信号の位相がかわるようにセットされている。この電磁ピックアップ７４からの交流信号は、基準位置検出器５で説明したと同様に図２に示す入力回路１４にて波形成形され、図７（ｄ）に示すパルス信号ＶｄとしてマイクロコンピュータＭＣに取り込まれる。
【００３１】
マイクロコンピュータＭＣではこのパルス信号Ｖｄとクランクの基準位置に対応するパルス信号Ｖｂとの時間差を求め、この時間差とエンジンの回転数ＮＥとに基づいて、基準位置から燃料の着火までに要したクランクの角度即ち実噴射時期ＴＰを算出する。一方目標噴射時期設定手段１０２では、エンジンの回転数ＮＥ、燃料の噴射量検出値および燃料温度とから予めメモリ内に格納したマップあるいは計算式により目標噴射時期を求める。
【００３２】
ここで本発明で実施される燃料噴射時期制御と、既述の各信号との関係について述べると、図７（ｃ）にて示す実着火時期ＴＴＰと目標着火時期との偏差に応じた補正項ΔＴを求め、このΔＴに基づいて目標噴射時期を補正するのであるが、この実施の形態の特徴とする点は、補正項ΔＴに対して、気筒別に重み付けをし更に運転状態に応じて重み付けをすることにある。この重み付けに関する部分は、図１の第１の重み係数設定手段１１０、第２の重み係数設定手段１１１及び重み付け手段１０９であり、これらの具体例について詳述する。
【００３３】
ここでは直列４気筒エンジンを例にして説明する。第１の重み係数は、図１０（ａ）のテ−ブルに示すように各気筒Ｃｙ１〜４毎に予め設定されている。この第１の重み係数の意味について述べる。直列４気筒エンジンにおいて、１つの振動センサによりすべての気筒の着火時期を検出しようとする場合には、既述したように気筒Ｃｙ２、３間に取り付けるのが好ましい。これは振動センサによって捕捉される燃焼振動レベルが気筒の間で大きく異ならないようにするためである。
【００３４】
このように振動センサを取り付けた場合、振動センサで捕捉される燃焼振動レベルは、気筒Ｃｙ２、３では比較的大きく、気筒Ｃｙ１、４では比較的小さい。即ち気筒Ｃｙ２、３の方が気筒Ｃｙ１、４よりも燃焼振動レベル以外の機械振動ノイズなどに対して強い、つまりＳ／Ｎが良い。このような理由から気筒Ｃｙ２、３の第１の重み係数は気筒Ｃｙ１、４の第１の重み係数よりも大きく設定する。この例では、夫々１．０及び０．７に設定されている。第１の重み係数の値はこの例に限られるものではなく、エンジンの種類などに応じて例えば実測デ−タに基づいて適宜設定すれば良い。
【００３５】
重み係数１は、実着火時期と目標着火時期との偏差ΔＴをそのまま使用して噴射時期を補正することを示し、重み係数＜１とは、重み付けの影響が小さいことを示す。
更に第２の重み係数は、以下のような点を考慮して運転状態に応じて決定される。例えば高回転数や、高負荷においては燃焼振動以外の機械振動ノイズが大きくなり、Ｓ／Ｎが悪くなるため着火時期の検出結果の重み付けを小さくするように重み係数が設定される。即ち気筒Ｃｙ１、４では機械振動ノイズに燃焼振動が隠れてしまって着火の検出ができない回転数や負荷条件下でも、気筒Ｃｙ２、３では燃焼振動を検出できる場合もあるため、図１０（ｂ）、（ｃ）の特性図に示すように回転数、負荷が大きくなるにつれて夫々重み係数Ｋｎ、ＫＡを小さくするように設定する。ただし本発明において第２の重み係数としては、ＫｎまたはＫＡのうちの一方を用いてもよい。これら図１０に示すデ−タは、マイクロコンピュ−タＭＣのメモリに格納される。
【００３６】
そして前記噴射時期調節手段３は、例えば図１１に示すように構成される。図１１において、タイマピストン３０はピン３１でロ−ラリング３２と接続されており、タイマピストン３０が図中左方に移動するとロ−ラリング３２が右回転方向に回動し、燃料噴射時期は進角側に変わるものである。
３３はベ−ン型燃料ポンプであり、噴射ポンプの図示しないドライブシャフトにより回転し、燃料タンクから燃料をポンプ内圧力室３４へ圧送する。圧力室３４内の燃料は機関へ噴射されると共に、絞りを通りタイマピストン高圧室３５へ導かれる。従って高圧室３５の圧力と低圧室３５ａ中のリタ−ンスプリング３６の力の釣り合う位置でタイマピストン３０の位置が定まるためロ−ラリング３２の位置が定まり、噴射時期が定まる。３７は圧力調整用の電磁弁であり、高圧室３５の圧力を、電子制御ユニット１０からの駆動信号により電磁弁３７の開閉時間比率を変えることにより制御し、タイマピストン３０の位置即ち噴射時期を決める。
【００３７】
次に上述の実施の形態の作用について、図１２〜図１６に示すマイクロコンピュ−タＭＣが行う処理のフロ−チャ−トを参照しながら説明する。図１２はメインル−チン、図１３〜図１８は割込みル−チンを示す。図中Ｐ、Ｒはステップを示す。図１２において電源投入時に、例えば後述のΔＴをクリアするなど、必要な初期化を行う。
【００３８】
続いてＰ２では図７（ｂ）に示す基準位置パルス（Ｖｂ）の周期ｔＭの逆数をとり、定数をかけることによりエンジン回転数ＮＥを求める。この際基準位置パルスの立ち上がりで図１３に示すル−チンの割込み処理がかかるようになっている。即ち基準位置パルスの立上がり時点でのタイマ値ｔｉをＲ１で読み込み、前サイクルでのタイマ値ｔ（ｉ−１）との差をＲ２で演算して周期ｔＭを求め、Ｒ３で基準クランク位置に対する実噴射時期位相（実噴射時期）ＴＰ＝ｔｉ−ｔｋを演算する。ｔｋの読み込みについては、噴射時期検出器７からの図７（ｄ）に示すパルス信号（Ｖｄ）の立上がり時点で図１４に示す割込みル−チンが起動され、Ｒ４でその立上がり時点のタイマ値ｔｋが読み込まれる。
【００３９】
次のＰ３では前述した噴射量検出器の値をＡ／Ｄ変換した値を読みこむ。メインル−チンのＰ４及びＰ５では、既述したように夫々目標噴射時期ＴＢ及び目標着火時期ＴＴＳを算出する。その後Ｐ６では実着火時期ＴＴＰを算出する。このステップＰ６においては、図７（ｃ）に示す着火検出信号（ＶＣ）が立ち上がると図１５に示す割込みル−チンが起動され、Ｒ５にて信号の立上がり時の時刻ｔｊを読取り、Ｒ６で直前に取り込まれた基準位置パルスの立上がり時刻ｔｉとの差を算出し、この差ｔｊ−ｔｉと回転数ＮＥとに基づいて実着火時期ＴＴＰを算出する。
【００４０】
次いでＰ７で目標着火時期ＴＴＳと実着火時期ＴＴＰとの偏差に応じたΔＴを求め、次のＰ８にてΔＴに対して以下のようにして重み付けを行う。先ず着火を検出した気筒の判別を行い、その気筒に対応した第１の重み係数Ｋｉを図１０（ａ）に示すテ−ブルから選択すると共に、エンジン回転数に応じた第２の重み係数Ｋｎ及び負荷（アクセル開度）に応じた第２の重み係数ＫＡを図１０（ｂ）、（ｃ）に示すデ−タから夫々選択する。そしてこれら重み係数の掛け算値Ｋ（Ｋｉ×Ｋｎ×ＫＡ）をト−タルの重み係数として、つまりいわば気筒の基本重み係数Ｋｉを運転状態に応じた重み係数により修正してト−タルの重み係数Ｋを求め、このＫにΔＴを掛け算してΔＴの重み付けを行う。
【００４１】
図１０（ａ）の例では振動センサの取付位置に近い気筒ほど重みづけを大きく、つまり振動センサによる着火時期検出精度が高いのでΔＴをそのまま反映させるようにしている。図１０（ｂ）、（ｃ）の例では、エンジン回転数が低く、あるいはアクセル開度が小さいときは、エンジン出力が低い状態で運転されているため、振動センサの検出精度が高いので、ΔＴをそのまま反映させるようにしている。
【００４２】
Ｐ９では、目標噴射時期ＴＢと補正項ΔＴを加算して補正後目標噴射時期ＴＢを算出する。続いてＰ１０にて実噴射時期を算出する。これは既述したステップＲ３で求めたＴＰを用いれば良い。次にＰ１１にて目標噴射時期ＴＢと実噴射時期ＴＰとの誤差に応じてこの誤差量を零にするように、図１１の電磁弁３７に出力する駆動信号のデュ−ティ比算出する。
【００４３】
以上Ｐ１１まで進んだらプログラムはＰ２へ戻り同様の処理を繰り返す。このようにプログラムがル−プを描きつつ計算を進めているうちに、ある一定時間毎に図１６の定時割り込みル−チンが発生し、Ｒ７で定時割込み処理をし、既に計算されたデュ−ティ比は、Ｒ８のステップで図２に示す出力回路１７から駆動出力周期に同期して発生する。こうして適切なデュ−ティ比の駆動信号が噴射時期調節手段３に供給され、燃料の噴射時期制御が行われる。
【００４４】
上述の実施の形態によれば、エンジンブロックＥＢに１個の振動センサ４を取り付けて４気筒の着火を検出するようにしているので、気筒毎に筒内にセンサを挿入するためのエンジンの加工を必要とせず、また気筒毎にセンサを設ける場合に比べてはるかに安価である。そして各気筒と振動センサ４との位置関係などに基づいて、着火の検出の信頼度に応じた重み付けを燃料噴射時期の補正項に対して行うと共に、更にエンジン回転数及び負荷に応じた重み付けも行って、回転数や負荷が高いときと低いときとの機械振動ノイズによる着火検出の信頼度の差をも噴射時期制御に反映させているため、高精度な噴射時期制御を行なうことができる。
【００４５】
ここで前記第２の重み係数については図１７及び図１９に示すような方法で設定してもよい。図１７に示す、第２の重み係数設定部１１１では、運転状態検出部１０１からエンジン回転数、アクセル開度、吸気圧及び燃料噴射量のうちの少なくとも１つ以上の情報に基づいて、エンジンの運転状態が定常であるか過渡であるかを運転状態判別部３０１で判別している。そしてテ−ブル３０２には、定常状態のときの重み係数と過渡状態のときの重み係数が規定されており、判別された運転状態に対応した重み係数が出力される。この場合過渡状態時の重み係数は、定常状態時の重み係数よりも小さく設定されている。この理由は過渡状態のときは定常状態のときにくらべて振動センサによる検出精度が劣るから振動センサ出力による着火のずれをそのまま反映させることを防ぐためである。なお過渡状態は複数の段階に分け、各段階毎に重み係数を設定してもよい。
【００４６】
また実燃料噴射量の代わりに、アクセル開度、エンジン回転数をパラメータとして演算される目標噴射量を使用して目標着火時期を演算してもよい。
また図１８に示す第２の重み係数設定部１１１は、エンジン回転数の変化率を演算する演算部３０３とアクセル開度の変化率を演算する演算部３０４とを有している。３０５は回転数変化率と重み係数との関係を規定したメモリ内のデ−タ、３０６はアクセル開度の変化率と重み係数との関係を規定したメモリ内のデ−タであり、マイクロコンピュ−タは、演算結果である各変化率に応じた重み係数をデ−タ３０５、３０６に基いて求め、得られた重み係数のうち小さい方の値が最小値出力部３０７から出力され、こうして第２の重み係数が設定される。なお第２の重み係数の設定の仕方については、これ以外の方法を採用してもよい。
【００４７】
また本発明では、気筒毎に求めた重み付け後のΔＴを例えば気筒Ｃｙ１〜Ｃｙ４について平均化し、その平均値を既述の実施の形態のΔＴの代りに使用してもよい。そしてまた振動センサを各気筒間で共通に使用するにあたっては、例えば４気筒エンジンの場合、気筒ＣＹ１、２について１個の振動センサを用い、気筒Ｃｙ３、４について１個の振動センサを用いて合計２個の振動センサを用いるようにしてもよい。また本発明では気筒ごとに振動センサを設け、求めた補正項に対して運転状態に応じた第２の重み付けをするようにしてもよい。
【００４８】
以上説明したフロ−チャ−トの説明では、基本目標噴射時期、目標着火時期、実噴射量をパラメ−タとして使用したが、このかわりにアクセル位置にそのまま置き換えても実施可能である。また、上記実施例では分配型の噴射ポンプを用いているが、ポンプ被駆動軸とクランク軸との回転位相を変化させて噴射時期を制御する列型の噴射ポンプにも同様に適用できる。
【００４９】
更に、上記実施例では、噴射時点検出器７の歯車７２は図９に示すように、ポンプ１回転（エンジン２回転）に２つの信号を発生する突起を設けており、これにより基準位置検出器５と歯数が合う。しかし、噴射時期制御と同時に噴射量制御を行なう場合、この状態ではエンジン回転に１歯の信号しか入力されず、この信号により回転数情報を得て該回転数情報にて噴射量制御を行なおうとすると、回転情報の入力頻度が粗く安定な制御が困難となる。
【００５０】
そこで他の実施例として、図１９に示すような歯車を利用することができる。この歯車７６には多くの歯がきざまれている（例えば図示の場合６４歯）。エンジン４気筒の場合、各気筒の噴射時期に対応する位置に４か所欠歯７ａ〜７ｄを設ける。この歯車７６により得られる信号は波形整形後に図２０のような波形になる。この信号をマイクロコンピュ−タＭＣに入力し、波形の立ち上がりから次の立ち上がりまでの時間を毎回計測し、その時間の大きさを見て欠歯を判定し、その欠歯の次の立ち上がり（Ｇ）を検出する。このＧ点を前記実施例の噴射時点検出信号のかわりに利用することもできる。この場合回転情報の入力頻度も多くなり、噴射量制御を安定して行うことが可能となる。
【００５１】
以上において、図２１に本発明の着火時期検出装置の実施の形態を示す。この装置の構成は、図１に示す燃料噴射時期制御装置における着火時期検出に関する部分と略同様であり、実着火時期が実着火時期補正手段１００にて、目標着火時期、第１及び第２の重み係数により補正される。補正演算の一例としては、目標着火時期と実着火時期との偏差に第１及び第２の重み係数を掛け算し、その結果を実着火時期に加算することが挙げられる。この場合振動センサによる着火の検出の信頼度が高くて重み付けが１であれば、実着火時期がそのまま検出実着火時期である出力値として取り扱われる。このようにすれば既に詳述したように高い精度で着火時期を検出できる効果がある。
【図面の簡単な説明】
【図１】本発明の実施の形態の全体の概略構成を示すブロック図である。
【図２】本発明の実施の形態の全体構成を具体化して示す構成図である。
【図３】振動センサを直列４気筒エンジンに取り付けた状態を示す側面図である。
【図４】振動センサからの電気信号を処理するための信号処理回路である。
【図５】図４に示す回路の各部の波形を示す信号波形図である。
【図６】基準位置検出器の検出信号を波形整形するための信号処理回路図である。
【図７】基準位置の検出信号、着火時点の検出信号及び噴射時点の検出信号を示す信号波形図である。
【図８】実噴射量検出器の取り付け状態を示す断面図である。
【図９】噴射時点検出器の取り付け状態を示す断面図である。
【図１０】第１及び第２の重み係数の設定の一例を示す説明図である。
【図１１】噴射時期調節手段を示す断面図である。
【図１２】本実施の形態の制御手順を示すフロ−チャ−トである。
【図１３】基準位置割込みル−チンを示すフロ−チャ−トである。
【図１４】噴射時期割込みル−チンを示すフロ−チャ−トである。
【図１５】実着火時割込みル−チンを示すフロ−チャ−トである。
【図１６】定時割込みル−チンを示すフロ−チャ−トである。
【図１７】第２の重み係数設定部の他の例を示す構成図である。
【図１８】第２の重み係数設定部の更に他の例を示す構成図である。
【図１９】噴射位置検出器の歯車を示す平面図である。
【図２０】噴射位置検出器からの検出信号を示す信号波形図である。
【図２１】本発明の着火時期検出装置の実施の形態の概略構成を示すブロック図である。
【符号の説明】
１０１運転状態検出手段
１０２目標噴射時期設定手段
１０４噴射時点検出手段
１０５基準位置検出手段
１０６着火検出手段
２０５振動センサ
１０９重み付け手段
１１０第１の重み係数設定手段
１１１第２の重み係数設定手段
１１３噴射時期調節手段
１ディ−ゼルエンジン
２噴射ポンプ
２１燃料噴射ノズル
３噴射時期調節手段
４振動センサ
５基準位置検出器
６燃料噴射量検出器
７噴射時点検出器
ＭＣマイクロコンピュ−タ
Ｃｙ１〜４気筒[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a device for controlling fuel injection timing and a device for detecting ignition timing.
[0002]
[Prior art]
Conventional diesel engines are known that control the fuel injection timing so that the fuel ignition timing becomes the target ignition timing. In order to perform this control, a means for detecting the ignition timing is required. Among the detection means, the vibration sensor is advantageous in that it does not require engine processing and is inexpensive.
[0003]
For example, Japanese Patent Application Laid-Open No. 60-138247 discloses a technique for controlling such fuel injection timing with a vibration sensor. In this publication, a vibration sensor composed of a piezoelectric element is provided in the fuel injection nozzle or nozzle holder of each cylinder, the moment of ignition is detected based on the vibration waveform detected by the vibration sensor, and the actual result obtained based on this detection result is obtained. Find the deviation between the ignition timing (phase of actual ignition with respect to the crank reference position) and the optimal target ignition timing according to the operating state of the engine, and give the output corresponding to this deviation to the injection timing adjustment timer for fuel injection It is described that the timing is controlled.
[0004]
Furthermore, Japanese Patent Laid-Open No. 59-185837 provides an ignition detector for each cylinder to obtain a deviation between the actual ignition timing obtained based on the detection signal of the ignition detector and the target ignition timing, A technique is disclosed in which an average value of deviations for four cylinders is obtained and reflected in a control signal for injection timing. In this technology, even if the injection timing is the same for each cylinder, the ignition timing varies between cylinders due to variations in compression ratio and temperature distribution, so that the detected ignition timing of each cylinder becomes the target ignition timing. The aim is to eliminate the variation in the ignition timing between cylinders by controlling the injection timing. As the ignition detector, it is described that a photo sensor that captures combustion light, an internal pressure sensor that detects pressure in a cylinder, or a vibration sensor is used.
[0005]
[Problems to be solved by the invention]
By the way, when using a photo sensor or an internal pressure sensor as an ignition detector, it is inserted directly into the cylinder of each cylinder and directly measures the combustion light and internal pressure, so it does not include factors such as superposition of mechanical vibration noise and detection delay. . On the other hand, when the vibration sensor is used, since the vibration of the cylinder is caught when the fuel explodes, there is the following problem.
[0006]
(1) First, when using a vibration sensor, it is advantageous in that an inexpensive system can be configured if the ignition timing of multiple cylinders, for example, four cylinders, is detected by one vibration sensor. However, in this case, the cylinder far from the vibration sensor has a low level of combustion vibration compared to the cylinder close to the vibration sensor, so it is weak against mechanical vibration noise other than the combustion vibration. Therefore, depending on the relative positional relationship between the vibration sensor and the cylinder, The reliability of the detected ignition timing is different. Further, since mechanical vibration noise is generated when the valve is seated, the reliability of the detected ignition timing is different between the cylinder in which the valve opening / closing timing and the combustion timing overlap and the cylinder that does not overlap.
[0007]
(2) Further, during high speed and / or high load operation, the vibration of the engine is larger than during low speed and / or low load operation, so that the mechanical vibration noise increases, and this noise signal is added to the electrical signal from the vibration sensor. Therefore, the S / N is deteriorated, and the detection accuracy at the moment of ignition, that is, the reliability of the detected actual ignition timing is lowered. Further, even in a situation where the rotational speed is not so high, mechanical vibration noise becomes large at the time of transition such as sudden acceleration, and the reliability similarly decreases.
[0008]
The present invention has been made under such circumstances, and an object of the present invention is to provide a device capable of realizing simple and highly accurate ignition timing control using a vibration sensor.
[0009]
[Means for Solving the Problems]
According to the first aspect of the present invention, vibrations of a plurality of cylinders of the engine are detected by a common vibration sensor, for example, one vibration sensor, and the detected vibrations are processed by a signal processing circuit to detect ignition in each cylinder. Based on the ignition detection signal from the ignition detection means, the actual ignition timing is obtained.
[0010]
On the other hand, a target ignition timing corresponding to the operating state is obtained by the target ignition timing setting means, and a correction term corresponding to a deviation between the target ignition timing and the actual ignition timing is obtained by the correction term calculation means. Then, a first weighting factor for each cylinder is set in advance by the first weighting factor setting means, and the correction term is weighted for each cylinder by the first weighting factor by the weighting means. The injection timing adjusting means is controlled based on the weighted correction term.
[0011]
According to the invention of claim 1, considering the difference in reliability for each cylinder for the detected actual ignition timing, for example, according to the reliability of the ignition timing detection signal corresponding to the positional relationship between each cylinder and the vibration sensor, Since the degree of contribution of the correction term to the fuel injection timing control is weighted, the fuel injection timing control can be performed at a lower cost and with higher accuracy than when a vibration sensor is provided for each cylinder.
[0012]
In the invention of claim 2, as in the case of claim 1, in controlling the injection timing adjusting means on the basis of the correction term corresponding to the deviation between the target ignition timing and the actual ignition timing, weighting in consideration of the operation state is performed. This is performed for the correction term. That is, a second weighting factor is set based on the detection signal detected by the operating state detection unit, and the correction term is weighted by the second weighting factor by the weighting unit. As a specific setting method of the weighting factor, for example, as described in claim 4, it is determined so that the influence of the weighting becomes smaller as the load is higher and / or the rotation is higher.
[0013]
According to the second aspect of the present invention, the difference in the reliability of the detected ignition timing according to the operating state is considered as the fuel injection timing in consideration of the influence of mechanical vibration noise due to the operating state when the ignition is detected using the vibration sensor. Since this is reflected in the control, highly accurate fuel injection timing control can be performed. As in the third aspect of the invention, when a common vibration sensor is used for a plurality of cylinders, a first weighting coefficient for each cylinder and a second weighting coefficient corresponding to the operating state are set and If the correction term is weighted, the fuel injection timing control with higher reliability can be performed as compared with the case where weighting is simply performed for each cylinder.
[0014]
Furthermore, in the ignition timing detection device according to claim 8, as in the case of claim 1, the actual ignition timing is obtained by the ignition detection means using the vibration sensor and the reference position detection means, and the target ignition timing is obtained by the target ignition timing setting means. . Then, a first weighting factor is set in advance for each cylinder by the first weighting factor setting means, the actual ignition timing is corrected for each cylinder by the target ignition timing and the first weighting factor, by the actual ignition timing correction means, The corrected actual ignition timing is set as the detected ignition timing. Therefore, since the detected actual ignition timing is corrected in consideration of the difference in reliability for each cylinder, it is possible to detect the ignition timing with high accuracy.
[0015]
In the ignition timing detection device of claim 9, the actual ignition timing is corrected by the target ignition timing and the weighting coefficient as in the case of the invention of claim 8. The weighting coefficient (second weighting coefficient) is an operating state detection unit. Is set based on the detection signal from Therefore, since the actual ignition timing is corrected in consideration of the influence of mechanical vibration noise due to the operating state when the ignition is detected using the vibration sensor, the ignition timing can be detected with high accuracy.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a block diagram showing the overall schematic configuration of the components of a fuel injection timing control apparatus according to an embodiment of the present invention. The outline of the present embodiment will be briefly described with reference to FIG. explain. The operating state detecting means 101 includes an engine speed detecting unit 201, an accelerator opening detecting unit 202, an intake pressure detecting unit 203, a fuel injection amount detecting unit 204, and the like.
[0017]
The target injection timing setting means 102 and the target ignition timing setting means 103 set the target injection timing and the target ignition timing, respectively, according to the detection signal from the operating state detection means 101. The actual injection timing calculation means 104a is based on the detection signals of the injection time detection means 104 for detecting the moment of fuel injection and the reference position detection means 105 for detecting the reference position of the crank. The crank angle (phase) at the time of injection is detected.
[0018]
On the other hand, the ignition detection means 106 includes one vibration sensor 205 and a signal processing circuit 206 provided in common for each cylinder of the engine, and the signal processing circuit 206 processes the vibration signal detected by the vibration sensor 205. And detect the moment of ignition. The actual ignition timing calculation means 107 detects the actual ignition timing, that is, the crank angle (phase) at the time of ignition with respect to the reference position, based on the detection signals of the ignition detection means 106 and the reference position detection means 105. The correction term calculation means 108 obtains a phase difference (correction term) between the target ignition timing and the actual ignition timing.
[0019]
The correction term is weighted by the weighting means 109 by multiplying the first weighting factor and the second weighting factor. The first weighting factor is set by the first weighting factor setting unit 110 according to the positional relationship between the cylinder and the vibration sensor, and the second weighting factor is set by the second weighting factor setting unit 111. It is set according to the detection signal from the state detection means 101. Then, the output value calculating means 112 corrects the target injection timing based on the weighted correction term, for example, adds the correction term to the target injection timing, and based on the difference between the corrected target injection timing and the actual injection timing. Then, a control signal is output to the injection timing adjusting means 133.
[0020]
Next, the specific configuration and operation of the fuel injection timing control device shown in FIG. 1 will be described in detail. FIG. 2 is a diagram showing a specific overall configuration of the fuel injection timing control device. Reference numeral 1 denotes, for example, an in-line four-cylinder diesel engine (engine), and reference numeral 2 denotes a distribution type fuel injection pump. Fuel pumped from the fuel injection pump 2 is injected into each cylinder through a fuel injection nozzle 21. The injection timing of the fuel injection pump 2 is adjusted by an injection timing adjusting means 3 to be described later called an electro-hydraulic timer.
[0021]
A vibration sensor 4 is attached to the diesel engine 1. The vibration sensor 4 detects the vibration of the engine block as an electrical signal by, for example, a piezoelectric element, and detects the moment of ignition based on this signal. In this example, the ignition of each cylinder is detected by one vibration sensor. To detect. FIG. 3 shows a preferable example in which a vibration sensor is attached to an in-line four-cylinder engine. In this case, the vibration sensor 4 is between the second and third cylinders Cy2 and Cy3 and is preferably near the upper end of the engine block EB. . Cy1 and Cy4 are cylinders, H is a head cover, and P is an oil pan.
[0022]
In the case of a V-type 6-cylinder engine, the vibration sensor 4 is preferably provided at the center of the bank. The reason for this is to prevent the vibration vibration trapped in a specific cylinder from becoming extremely small by selecting a target position for each cylinder as much as possible with respect to the mounting position of the vibration sensor 4. .
The vibration signal (electric signal converted by the piezoelectric element) detected by the vibration sensor 4 in this way is input to the signal processing circuit 40 shown in FIG. That is, the vibration signal is input to the filter 41, where high-frequency noise and DC components are removed, and then input to the integration circuit 42 and the peak hold circuit 43. The outputs of the circuits 42 and 43 are input to both input terminals of the comparator 44, respectively. The comparator 44 has an output level “H” (for example, a signal of 5 V) when the output from the peak hold circuit 43 is larger than the output from the integrating circuit 42, and “L” (for example, for example) otherwise. 0V signal) level.
[0023]
When the level of combustion vibration is small and the output of the peak hold circuit 43 does not exceed the output of the integration circuit 42, the output voltage of the comparator remains 0V. A reset signal is input to the peak hold circuit 43 from the engine control microcomputer 45. This reset signal is output at 90 ° CA after the compression TDC of the engine and is reset every combustion. . Details of the operation of the processing circuit of FIG. 4 are shown in FIG. A signal obtained by filtering the signal from the vibration sensor 4 is (a). Cy1 to Cy4 are attached to represent them in correspondence. The waveform obtained by inputting the filtered signal to the integrating circuit 42 is like Vi shown by a dotted line in FIG. The waveform obtained by inputting to the peak hold circuit 43 is as shown by VP indicated by a solid line in FIG. When these two signals (Vi, VP) are input to the comparator 44, VC shown in (c) is obtained from the output terminal of the comparator 44.
[0024]
The signal processing circuit 40 corresponds to the input circuit 11 in the electronic control unit 10 shown in FIG. 2, and the signal obtained by the input circuit 11, that is, the output signal VC of the comparator 44 shown in FIG. 5, is input to the microcomputer MC. The In this example, the vibration sensor 4 and the signal processing circuit 40 constitute an ignition detection means.
The ignition moment is detected as described above. Based on this detection signal, the phase at the time of ignition with respect to the reference position of the crank, that is, the ignition timing (actual ignition timing) is obtained as follows. In FIG. 2, a reference position detector which is a reference position detecting means for detecting the reference position of the crank is indicated by reference numeral 5, and a signal from the reference position detector 5 is taken into the microcomputer MC via the input circuit 12. . As shown in FIG. 6, the reference position detector 5 includes a gear 51 and an electromagnetic pickup 52 that rotate in synchronization with the crankshaft and have one protrusion, and protrude at the reference crank position after top dead center. Is opposed to the electromagnetic pickup 52, and thereby, an AC signal Va as shown in FIG.
[0025]
When this AC signal is input to the input circuit 12, the waveform is formed into a pulse signal Vb as shown in FIG. The microcomputer MC calculates the engine speed by counting the pulse interval tM of the pulse signal Vb. In the microcomputer MC, a time difference between the pulse signal Vb corresponding to the crank reference position and the pulse signal Vc, which is a detection signal from the ignition detection means, is obtained, and the fuel is calculated from the reference position based on the time difference and the engine speed. The crank angle required until the ignition of, that is, the actual ignition timing TTP is calculated.
[0026]
As described above, in the present embodiment, the actual ignition timing calculation unit 107 shown in FIG. 1 includes the microcomputer MC, but the target ignition timing setting means 103, the correction term calculation means 108, the target injection timing setting means 102, The first weight coefficient setting means 110, the second weight coefficient setting means 111, the output value calculation means 112, and the like are also configured by the microcomputer MC, and each process is executed by software.
[0027]
Next, each of these components will be described specifically. First, the target ignition timing setting means 103 uses a map or calculation formula stored in advance in the memory from the engine speed NE detected as described above and the detected value (actual injection amount) of the fuel injection amount. Find the target ignition timing.
The fuel injection amount is detected by using a fuel injection amount detector 6 provided in combination with the injection pump 2 as shown in FIG. An example of the fuel injection amount detector 6 is shown in FIG. 8. 61 is a spill ring of the injection pump, 62 is a plunger, and the face 62 (not shown) moves the plunger 62 from side to side while rotating to pump fuel. Distribute. The movable core 63 of the detector 60 is integrally fixed to the spill ring 61 via a lever, and two pairs of coils 64 are wound around the outer periphery of the cylindrical bobbin. The main body is fixed to the pump head with a fixing screw 65.
[0028]
The detection of the injection amount utilizes the fact that the inductance of the coil 64 changes when the movable core 63 slides in the two pairs of coils 64, and the spill ring 61 is shown when the fuel injection amount is small. It is located in the middle left and moves to the right when a large amount of fuel injection is required. Therefore, when the fuel injection amount is large, the output voltage value is low, for example, 1 V, and when the injection amount is small as in the idling state, the spill ring 21 moves to the left, and the stroke of the core 63 For example, the output voltage is 3V. The fuel injection amount detection signal (analog voltage) thus obtained is taken into the microcomputer MC via the A / D converter 13 shown in FIG.
[0029]
Returning to the overall configuration diagram of FIG. 2, reference numeral 15 denotes an accelerator position detector that detects the amount of accelerator depression, and reference numeral 16 denotes a temperature detector that detects the fuel temperature of the engine 1. Each detection signal is taken into the microcomputer MC via the A / D converter 13. On the output side of the microcomputer MC, an output circuit 17 is provided for giving a pulse signal having an appropriate duty ratio to an injection timing adjusting means 3 described later.
[0030]
The fuel injection timing is detected by using an injection timing detector 7 attached to the injection pump 2 as shown in FIG. An example of the injection timing detector 7 is shown in FIG. 9. A gear 72 having two protrusions 71, 71 provided at intervals of 180 degrees is attached to a drive shaft 73 of the injection pump 2. The electromagnetic pickup 74 for detecting the protrusions 71 and 71 is attached to a roller ring 75. When the injection timing is changed, the electromagnetic pickup 74 also rotates around the drive shaft 73 together with the roller ring 75, and the phase of the generated signal. It is set to change. The AC signal from the electromagnetic pickup 74 is shaped by the input circuit 14 shown in FIG. 2 in the same manner as described for the reference position detector 5, and is taken into the microcomputer MC as the pulse signal Vd shown in FIG. 7 (d). It is.
[0031]
The microcomputer MC obtains a time difference between the pulse signal Vd and the pulse signal Vb corresponding to the reference position of the crank, and based on this time difference and the engine speed NE, the crank speed required from the reference position to the ignition of the fuel is calculated. An angle, that is, an actual injection timing TP is calculated. On the other hand, the target injection timing setting means 102 obtains the target injection timing from the engine speed NE, the detected fuel injection amount value, and the fuel temperature by using a map or formula stored in advance in the memory.
[0032]
Here, the relationship between the fuel injection timing control performed in the present invention and each of the above-described signals will be described. A correction term corresponding to the deviation between the actual ignition timing TTP and the target ignition timing shown in FIG. ΔT is obtained and the target injection timing is corrected based on this ΔT. The feature of this embodiment is that the correction term ΔT is weighted for each cylinder and further weighted according to the operating state. There is to do. The parts relating to the weighting are the first weighting factor setting unit 110, the second weighting factor setting unit 111, and the weighting unit 109 in FIG. 1, and specific examples thereof will be described in detail.
[0033]
Here, an inline 4-cylinder engine will be described as an example. The first weight coefficient is set in advance for each of the cylinders Cy1 to Cy4 as shown in the table of FIG. The meaning of this first weighting factor will be described. In the in-line four-cylinder engine, when it is intended to detect the ignition timing of all the cylinders with one vibration sensor, it is preferable that the in-line four-cylinder engine is installed between the cylinders Cy2 and Cy3. This is to prevent the combustion vibration level captured by the vibration sensor from greatly differing between the cylinders.
[0034]
When the vibration sensor is attached in this way, the combustion vibration level captured by the vibration sensor is relatively large in the cylinders Cy2 and 3 and relatively small in the cylinders Cy1 and 4. That is, the cylinders Cy2 and 3 are stronger than the cylinders Cy1 and 4 against mechanical vibration noise other than the combustion vibration level, that is, S / N is better. For this reason, the first weighting coefficient of the cylinders Cy2 and 3 is set larger than the first weighting coefficient of the cylinders Cy1 and Cy4. In this example, it is set to 1.0 and 0.7, respectively. The value of the first weighting factor is not limited to this example, and may be set as appropriate based on, for example, measured data according to the type of engine.
[0035]
A weighting factor of 1 indicates that the deviation ΔT between the actual ignition timing and the target ignition timing is used as it is to correct the injection timing, and a weighting factor of <1 indicates that the influence of weighting is small.
Further, the second weighting factor is determined according to the operating state in consideration of the following points. For example, at high rotation speeds and high loads, mechanical vibration noise other than combustion vibration increases, and the S / N deteriorates. Therefore, the weighting coefficient is set so as to reduce the weighting of the ignition timing detection result. That is, in the cylinders Cy1 and 4, since the combustion vibration is hidden behind the mechanical vibration noise and the ignition cannot be detected, the combustion vibration may be detected in the cylinders Cy2 and 3 even under a load condition. As shown in the characteristic diagram of (c), the weighting factors Kn and KA are set to decrease as the rotational speed and load increase. However, in the present invention, one of Kn or KA may be used as the second weighting factor. These data shown in FIG. 10 are stored in the memory of the microcomputer MC.
[0036]
The injection timing adjusting means 3 is configured as shown in FIG. 11, for example. In FIG. 11, the timer piston 30 is connected to a roller ring 32 by a pin 31. When the timer piston 30 moves to the left in the figure, the roller ring 32 rotates in the clockwise direction, and the fuel injection timing advances. It changes to the corner side.
Reference numeral 33 denotes a vane type fuel pump, which is rotated by a drive shaft (not shown) of the injection pump to pump fuel from the fuel tank to the pressure chamber 34 in the pump. The fuel in the pressure chamber 34 is injected into the engine and led to the timer piston high pressure chamber 35 through the throttle. Therefore, since the position of the timer piston 30 is determined at a position where the pressure of the high pressure chamber 35 and the force of the return spring 36 in the low pressure chamber 35a are balanced, the position of the roller ring 32 is determined and the injection timing is determined. 37 is an electromagnetic valve for adjusting the pressure, and controls the pressure of the high pressure chamber 35 by changing the opening / closing time ratio of the electromagnetic valve 37 by the drive signal from the electronic control unit 10, and the position of the timer piston 30, that is, the injection timing. Decide.
[0037]
Next, the operation of the above-described embodiment will be described with reference to a flowchart of processing performed by the microcomputer MC shown in FIGS. 12 shows the main routine, and FIGS. 13 to 18 show the interrupt routine. P and R in the figure indicate steps. In FIG. 12, when the power is turned on, for example, necessary initialization is performed such as clearing ΔT described later.
[0038]
Subsequently, at P2, the engine speed NE is obtained by taking the inverse of the cycle tM of the reference position pulse (Vb) shown in FIG. 7B and multiplying by a constant. At this time, the routine interrupt processing shown in FIG. 13 is started at the rising edge of the reference position pulse. That is, the timer value ti at the time of rising of the reference position pulse is read with R1, the difference from the timer value t (i-1) in the previous cycle is calculated with R2, the period tM is obtained, and the actual value relative to the reference crank position with R3. An injection timing phase (actual injection timing) TP = ti−tk is calculated. Regarding the reading of tk, the interrupt routine shown in FIG. 14 is activated at the rise of the pulse signal (Vd) shown in FIG. 7 (d) from the injection timing detector 7, and the timer value tk at the rise at R4. Is read.
[0039]
In the next P3, a value obtained by A / D converting the value of the injection amount detector described above is read. In the main routines P4 and P5, the target injection timing TB and the target ignition timing TTS are calculated as described above. Thereafter, at P6, the actual ignition timing TTP is calculated. In this step P6, when the ignition detection signal (VC) shown in FIG. 7 (c) rises, the interrupt routine shown in FIG. 15 is activated, reads the time tj at the rise of the signal at R5, and immediately before at R6. The difference from the rise time ti of the reference position pulse taken in is calculated, and the actual ignition timing TTP is calculated based on the difference tj−ti and the rotational speed NE.
[0040]
Next, at P7, ΔT corresponding to the deviation between the target ignition timing TTS and the actual ignition timing TTP is obtained, and at the next P8, ΔT is weighted as follows. First, the cylinder in which the ignition is detected is determined, and the first weight coefficient Ki corresponding to the cylinder is selected from the table shown in FIG. 10A, and the second weight coefficient Kn according to the engine speed is selected. The second weighting coefficient KA corresponding to the load (accelerator opening) is selected from the data shown in FIGS. 10 (b) and 10 (c). Then, the multiplication value K (Ki × Kn × KA) of these weighting factors is used as a total weighting factor, that is, the basic weighting factor Ki of the cylinder is corrected by a weighting factor according to the operating state, and the total weighting factor is calculated. K is obtained, and ΔT is multiplied by ΔT to weight ΔT.
[0041]
In the example of FIG. 10 (a), the closer the cylinder is to the vibration sensor mounting position, the greater the weighting, that is, the higher the ignition timing detection accuracy by the vibration sensor, so ΔT is reflected as it is. In the examples of FIGS. 10B and 10C, when the engine speed is low or the accelerator opening is small, the engine output is low and the vibration sensor has high detection accuracy. Is reflected as it is.
[0042]
In P9, the corrected target injection timing TB is calculated by adding the target injection timing TB and the correction term ΔT. Subsequently, the actual injection timing is calculated at P10. For this purpose, the TP obtained in step R3 described above may be used. Next, at P11, the duty ratio of the drive signal output to the solenoid valve 37 of FIG. 11 is calculated so that this error amount becomes zero according to the error between the target injection timing TB and the actual injection timing TP.
[0043]
After proceeding to P11, the program returns to P2 and repeats the same processing. As the program proceeds with the calculation while drawing the loop in this way, the scheduled interrupt routine of FIG. 16 is generated every certain time, the scheduled interrupt processing is performed at R7, and the already calculated duplication is performed. The tee ratio is generated in synchronization with the drive output period from the output circuit 17 shown in FIG. In this way, a drive signal with an appropriate duty ratio is supplied to the injection timing adjusting means 3 to control the fuel injection timing.
[0044]
According to the above-described embodiment, since one vibration sensor 4 is attached to the engine block EB to detect the ignition of the four cylinders, engine processing for inserting a sensor into the cylinder for each cylinder is performed. Is much cheaper than the case where a sensor is provided for each cylinder. Based on the positional relationship between each cylinder and the vibration sensor 4, etc., weighting according to the reliability of detection of ignition is performed on the correction term of the fuel injection timing, and further weighting according to the engine speed and load is also performed. Since the difference in the reliability of ignition detection due to mechanical vibration noise between when the rotational speed and load are high and low is also reflected in the injection timing control, highly accurate injection timing control can be performed.
[0045]
Here, the second weighting factor may be set by a method as shown in FIGS. In the second weighting factor setting unit 111 shown in FIG. 17, based on at least one information of the engine speed, the accelerator opening, the intake pressure, and the fuel injection amount from the operating state detection unit 101, An operation state determination unit 301 determines whether the operation state is steady or transient. The table 302 defines a weighting factor in a steady state and a weighting factor in a transient state, and outputs a weighting factor corresponding to the determined operating state. In this case, the weighting factor in the transient state is set smaller than the weighting factor in the steady state. This is because the detection accuracy by the vibration sensor is inferior in the transient state as compared with the steady state, so that the deviation of ignition due to the vibration sensor output is not reflected as it is. The transient state may be divided into a plurality of stages, and a weighting coefficient may be set for each stage.
[0046]
Further, instead of the actual fuel injection amount, the target ignition timing may be calculated using the target injection amount calculated using the accelerator opening and the engine speed as parameters.
The second weighting factor setting unit 111 shown in FIG. 18 includes a calculation unit 303 that calculates the rate of change of the engine speed and a calculation unit 304 that calculates the rate of change of the accelerator opening. Reference numeral 305 denotes data in the memory that defines the relationship between the rotational speed change rate and the weighting coefficient, and reference numeral 306 denotes data in the memory that defines the relationship between the change rate of the accelerator opening and the weighting coefficient. The data is obtained based on the data 305 and 306 for the weighting coefficient corresponding to each change rate which is the calculation result, and the smaller value of the obtained weighting coefficients is output from the minimum value output unit 307. A second weighting factor is set. Note that other methods may be employed for setting the second weighting factor.
[0047]
In the present invention, the weighted ΔT obtained for each cylinder may be averaged for, for example, the cylinders Cy1 to Cy4, and the average value may be used instead of ΔT in the above-described embodiment. In addition, when the vibration sensor is used in common among the cylinders, for example, in the case of a four-cylinder engine, one vibration sensor is used for the cylinders CY1 and 2 and one vibration sensor is used for the cylinders Cy3 and 4 in total. Two vibration sensors may be used. In the present invention, a vibration sensor may be provided for each cylinder, and a second weight corresponding to the operating state may be given to the obtained correction term.
[0048]
In the description of the flow chart described above, the basic target injection timing, the target ignition timing, and the actual injection amount are used as parameters, but it can be implemented by replacing them with the accelerator position instead. Moreover, although the distribution type injection pump is used in the above embodiment, the present invention can be similarly applied to a row type injection pump that controls the injection timing by changing the rotational phase of the pump driven shaft and the crankshaft.
[0049]
Further, in the above embodiment, the gear 72 of the injection point detector 7 is provided with a projection for generating two signals for one rotation of the pump (two rotations of the engine) as shown in FIG. 5 matches the number of teeth. However, when the injection amount control is performed simultaneously with the injection timing control, only one tooth signal is input to the engine rotation in this state, and the rotation number information is obtained from this signal and the injection amount control is performed based on the rotation number information. If this is the case, the rotation information is input frequently and stable control becomes difficult.
[0050]
Therefore, as another embodiment, a gear as shown in FIG. 19 can be used. The gear 76 has many teeth (for example, 64 teeth in the figure). In the case of a 4-cylinder engine, four missing teeth 7a to 7d are provided at positions corresponding to the injection timing of each cylinder. The signal obtained by the gear 76 has a waveform as shown in FIG. 20 after waveform shaping. This signal is input to the microcomputer MC, the time from the rising edge of the waveform to the next rising edge is measured each time, the missing tooth is determined by looking at the time, and the next rising edge (G ) Is detected. This point G can also be used in place of the injection time point detection signal of the above embodiment. In this case, the input frequency of the rotation information is increased, and the injection amount control can be stably performed.
[0051]
In the above, FIG. 21 shows an embodiment of the ignition timing detection device of the present invention. The configuration of this device is substantially the same as the portion relating to the ignition timing detection in the fuel injection timing control device shown in FIG. 1, and the actual ignition timing is determined by the actual ignition timing correction means 100 at the target ignition timing, the first and second ignition timings. It is corrected by the weighting factor. An example of the correction calculation is to multiply the deviation between the target ignition timing and the actual ignition timing by the first and second weighting factors and add the result to the actual ignition timing. In this case, if the reliability of detection of ignition by the vibration sensor is high and the weight is 1, the actual ignition timing is handled as an output value that is the detected actual ignition timing as it is. In this way, the ignition timing can be detected with high accuracy as already described in detail.
[Brief description of the drawings]
FIG. 1 is a block diagram showing an overall schematic configuration of an embodiment of the present invention.
FIG. 2 is a configuration diagram specifically illustrating an overall configuration of an embodiment of the present invention.
FIG. 3 is a side view showing a state in which a vibration sensor is attached to an in-line four-cylinder engine.
FIG. 4 is a signal processing circuit for processing an electrical signal from a vibration sensor.
5 is a signal waveform diagram showing waveforms at various parts of the circuit shown in FIG. 4. FIG.
FIG. 6 is a signal processing circuit diagram for waveform shaping of a detection signal of a reference position detector.
FIG. 7 is a signal waveform diagram showing a reference position detection signal, an ignition timing detection signal, and an injection timing detection signal.
FIG. 8 is a cross-sectional view showing an attached state of an actual injection amount detector.
FIG. 9 is a cross-sectional view showing a mounting state of an injection time point detector.
FIG. 10 is an explanatory diagram showing an example of setting first and second weighting factors.
FIG. 11 is a cross-sectional view showing injection timing adjusting means.
FIG. 12 is a flowchart showing a control procedure of the present embodiment.
FIG. 13 is a flowchart showing a reference position interrupt routine.
FIG. 14 is a flowchart showing an injection timing interrupt routine.
FIG. 15 is a flowchart showing an interrupt routine upon actual ignition.
FIG. 16 is a flowchart showing a scheduled interrupt routine.
FIG. 17 is a configuration diagram illustrating another example of the second weighting coefficient setting unit.
FIG. 18 is a configuration diagram illustrating still another example of the second weighting coefficient setting unit.
FIG. 19 is a plan view showing a gear of an injection position detector.
FIG. 20 is a signal waveform diagram showing a detection signal from an injection position detector.
FIG. 21 is a block diagram showing a schematic configuration of an embodiment of an ignition timing detection apparatus of the present invention.
[Explanation of symbols]
101 Operating state detection means
102 Target injection timing setting means
104 Injection point detection means
105 Reference position detection means
106 Ignition detection means
205 Vibration sensor
109 Weighting means
110 First weighting factor setting means
111 Second weight coefficient setting means
113 Injection timing adjusting means
1 Diesel engine
2 Injection pump
21 Fuel injection nozzle
3 Injection timing adjustment means
4 Vibration sensor
5 Reference position detector
6 Fuel injection amount detector
7 Injection point detector
MC Microcomputer
Cy1-4 cylinder

Claims

Ignition detection means for detecting vibrations of a plurality of cylinders of the engine with a common vibration sensor, and detecting ignition in each cylinder based on the detected vibrations;
Operating state detecting means for detecting the operating state of the engine;
Target ignition timing setting means for setting a target ignition timing according to the driving state;
Injection timing adjusting means for adjusting the injection timing of fuel into the cylinder of the engine;
Correction term calculation means for obtaining a correction term of injection timing based on deviations of signals from the ignition detection means and target ignition timing setting means,
In the fuel injection timing control device for controlling the fuel injection timing based on the correction term,
First weighting factor setting means for presetting a first weighting factor corresponding to a relative position with respect to the vibration sensor for each cylinder;
Weighting means for weighting the correction term for each cylinder by multiplying the correction term by the first weighting coefficient ;
A fuel injection timing control apparatus for controlling a fuel injection timing based on a correction term weighted by the weighting means.

Ignition detection means for detecting vibrations of the cylinders of the engine with a vibration sensor and detecting ignition in the cylinders based on the detected vibrations;
Operating state detecting means for detecting the operating state of the engine;
Target ignition timing setting means for setting a target ignition timing according to the driving state;
Injection timing adjusting means for adjusting the injection timing of fuel into the cylinder of the engine;
Correction term calculation means for obtaining a correction term of injection timing based on deviations of signals from the ignition detection means and target ignition timing setting means,
In the fuel injection timing control device for controlling the fuel injection timing based on the correction term,
Second weighting factor setting means for setting a second weighting factor based on a detection signal from the operating state detection means;
Weighting means for weighting the correction term by multiplying the correction term by the second weighting factor ,
A fuel injection timing control apparatus for controlling a fuel injection timing based on a correction term weighted by the weighting means.

Second weighting factor setting means for setting a second weighting factor based on a detection signal from the operating state detection means;
Weighting means for weighting the correction term for each cylinder by multiplying the correction term by the first weighting factor and the second weighting factor;
2. The fuel injection timing control apparatus according to claim 1, wherein the fuel injection timing is controlled based on a correction term weighted by the weighting means.

4. The fuel injection timing control according to claim 2, wherein the second weighting factor setting means sets the weighting factor so that the influence of weighting becomes smaller as the load becomes higher and / or the rotation becomes higher. apparatus.

The operating state detecting means detects at least one of the engine speed, the accelerator opening, the intake pressure, and the fuel injection amount,
The second weighting factor setting means determines whether the engine operating state is a steady state or an excessive state based on the information obtained by the operating state detection unit, and weights when determining that the engine is in an excessive state. 5. The fuel injection timing control device according to claim 2, wherein the weighting coefficient is set so that the influence of is less than that in a steady state.

The second weighting factor setting means calculates the rate of change of the engine speed and / or the rate of change of the opening of the accelerator, and when the engine operating state is in an excessive state, the larger the rate of change, the greater the influence of weighting. 6. The fuel injection timing control device for a diesel engine according to claim 5, wherein a weighting coefficient is set so as to reduce the fuel consumption.

4. The fuel injection timing is controlled based on the correction term by calculating an average value between the cylinders for the correction term obtained by the weighting means and using the average value as a correction term. Fuel injection timing control device.

  Ignition detection means for detecting vibrations of the cylinders of the engine with a vibration sensor and detecting ignition in the cylinders based on the detected vibrations;
  Operating state detecting means for detecting the operating state of the engine;
  Target ignition timing setting means for setting a target ignition timing according to the driving state;
  Injection timing adjusting means for adjusting the injection timing of fuel into the cylinder of the engine;
  Correction term calculation means for obtaining a correction term of injection timing based on deviations of signals from the ignition detection means and target ignition timing setting means,
  In the fuel injection timing control device for controlling the fuel injection timing based on the correction term,
  Second weighting factor setting means for setting a second weighting factor based on a detection signal from the operating state detection means;
  Weighting means for weighting the correction term by the second weighting coefficient,
  The second weighting coefficient setting means sets the weighting coefficient so that the influence of the weighting becomes smaller as the load becomes higher and / or the rotation becomes higher.
  A fuel injection timing control apparatus for controlling a fuel injection timing based on a correction term weighted by the weighting means.

  First weighting factor setting means for presetting a first weighting factor corresponding to a relative position with respect to the vibration sensor for each cylinder;
  Weighting means for weighting the correction term for each cylinder by the first weighting factor and the second weighting factor,
  9. The fuel injection timing control device according to claim 8, wherein the fuel injection timing is controlled based on a correction term weighted by the weighting means.

  Ignition detection means for detecting vibrations of the cylinders of the engine with a vibration sensor and detecting ignition in the cylinders based on the detected vibrations;
  Operating state detecting means for detecting the operating state of the engine;
  Target ignition timing setting means for setting a target ignition timing according to the driving state;
  Injection timing adjusting means for adjusting the injection timing of fuel into the cylinder of the engine;
  Correction term calculation means for obtaining a correction term of injection timing based on deviations of signals from the ignition detection means and target ignition timing setting means,
  In the fuel injection timing control device for controlling the fuel injection timing based on the correction term,
  Second weighting factor setting means for setting a second weighting factor based on a detection signal from the operating state detection means;
  Weighting means for weighting the correction term by the second weighting coefficient,
  The operating state detecting means detects at least one of the engine speed, the accelerator opening, the intake pressure, and the fuel injection amount,
  The second weighting factor setting means determines whether the engine operating state is a steady state or an excessive state based on the information obtained by the operating state detection unit, and weights when determining that the engine is in an excessive state. The weighting factor is set so that the influence of is smaller than in the steady state,
  A fuel injection timing control apparatus for controlling a fuel injection timing based on a correction term weighted by the weighting means.

First weighting factor setting means for presetting a first weighting factor corresponding to a relative position with respect to the vibration sensor for each cylinder;
Weighting means for weighting the correction term for each cylinder by the first weighting factor and the second weighting factor,
11. The fuel injection timing control apparatus according to claim 10, wherein the fuel injection timing is controlled based on a correction term weighted by the weighting means.

The operating state detecting means detects at least one of the engine speed, the accelerator opening, the intake pressure, and the fuel injection amount,
The second weighting factor setting means operates the engine based on the information obtained by the operating state detection means. It is characterized by determining whether the state is a steady state or an excessive state, and setting a weighting factor so that the influence of weighting is smaller than that in the steady state when it is determined that the state is an excessive state. The fuel injection timing control device according to claim 8 or 9.

The second weighting factor setting means calculates the rate of change of the engine speed and / or the rate of change of the opening of the accelerator, and when the engine operating state is in an excessive state, the larger the rate of change, the greater the influence of weighting. 13. The fuel injection timing control device for a diesel engine according to claim 10, 11 or 12, wherein a weighting coefficient is set so as to be small.

Reference position detecting means for detecting a predetermined rotational angle position of the engine;
  Ignition detection means for detecting vibrations of a plurality of cylinders of the engine with a common vibration sensor, and detecting ignition in each cylinder based on the detected vibrations;
  Target ignition timing setting means for setting a target ignition timing according to the driving state;
  Actual ignition timing calculating means for calculating the actual ignition timing based on each signal from the reference position detecting means and the ignition detecting means;
  First weighting factor setting means for presetting a first weighting factor for each cylinder;
  Actual ignition timing correction means for correcting the actual ignition timing for each cylinder by adding the result of multiplying the deviation between the target ignition timing and the actual ignition timing by the first weighting factor to the actual ignition timing. And,
  An ignition timing detection apparatus characterized in that an actual ignition timing obtained by the actual ignition timing correction means is set as a detected ignition timing.

Reference position detecting means for detecting a predetermined rotational angle position of the engine;
Ignition detection means for detecting vibration of the cylinder of the engine with a vibration sensor and detecting ignition in the cylinder based on the detected vibration;
  Target ignition timing setting means for obtaining a target ignition timing according to the driving state;
  Actual ignition timing calculating means for calculating the actual ignition timing based on each signal from the reference position detecting means and the ignition detecting means;
  Operating state detecting means for detecting the operating state of the engine;
  Second weighting factor setting means for setting a second weighting factor based on a detection signal from the operating state detection means;
  An actual ignition timing correction means for correcting the actual ignition timing by adding a result obtained by multiplying the deviation between the target ignition timing and the actual ignition timing by the second weighting factor to the actual ignition timing; Provided,
  An ignition timing detection apparatus characterized in that an actual ignition timing obtained by the actual ignition timing correction means is set as a detected ignition timing.

An operating state detecting means for detecting the operating state of the engine;
Providing a second weighting coefficient setting means for setting a second weighting coefficient based on a detection signal from the operating state detection means,
The actual ignition timing correction means adds the result obtained by multiplying the deviation between the target ignition timing and the actual ignition timing by the first weighting factor and the second weighting factor to the actual ignition timing. The ignition timing detection apparatus according to claim 14, wherein the actual ignition timing is corrected.