JP4051981B2 - Glow plug abnormality detection method and apparatus - Google Patents

Description

ここで、ＱＩＰはアイドル時にエアコンなどの負荷が生じている場合のオフセット値であり、ＱＩＰＢはアイドル以外の場合にエアコンなどの負荷が生じている場合のオフセット値である。また、ＭＡＸ（）は、括弧内の値の内の最大値を抽出する演算子である。
【０１１７】
次に、加減速時か否かが判定される（Ｓ２００）。この判定は、例えば、ガバナ噴射量指令値ＱＧＯＶが、前回の制御周期時に算出されている基本噴射量指令値ＱＢＡＳＥＯＬに比較して大きくあるいは小さくなっているか否かにより判定される。
【０１１８】
加減速時であれば（Ｓ２００で「ＹＥＳ」）、次にガバナ噴射量指令値ＱＧＯＶの増減抑制処理がなされる。これはガバナ噴射量指令値ＱＧＯＶが急速に変化する場合に生じるショックを防止するために行われるものである。したがって基本噴射量指令値ＱＢＡＳＥＯＬに比較して大きく変化したガバナ噴射量指令値ＱＧＯＶがステップＳ１９０にて算出された場合には、ガバナ噴射量指令値ＱＧＯＶの値はショックが生じないように補正される。
【０１１９】
次に基本噴射量指令値ＱＢＡＳＥとしてガバナ噴射量指令値ＱＧＯＶの値が設定される（Ｓ２２０）。なおステップＳ２００にて加減速時でないと判定された場合（Ｓ２００で「ＮＯ」）は、直接、ステップＳ２２０の処理に移る。
【０１２０】
そして、この基本噴射量指令値ＱＢＡＳＥを、次式４に表すごとく最大噴射量指令値ＱＦＵＬＬにてガード処理して最終基本噴射量指令値ＱＦＩＮＣを算出する（Ｓ２３０）。
【０１２１】
【数４】
ＱＦＩＮＣ ← ＭＩＮ（ＱＢＡＳＥ，ＱＦＵＬＬ） … ［式４］
ここで、ＭＩＮ（）は、括弧内の値の内の最小値を抽出する演算子である。
【０１２２】
次に、次式５に示すごとく、最終基本噴射量指令値ＱＦＩＮＣからパイロット噴射量指令値ＱＰＬが減算されて、メイン噴射量指令値ＱＦＰＬが算出される（Ｓ２４０）。
【０１２３】
【数５】
ＱＦＰＬ ← ＱＦＩＮＣ − ＱＰＬ … ［式５］
次に、メイン噴射量指令値ＱＦＰＬの値に基づいて、マップあるいは関数ｆｑによりメイン噴射期間ＴＱＦＰＬが算出される（Ｓ２５０）。更に、パイロット噴射量指令値ＱＰＬの値に基づいて、マップあるいは関数ｆｐによりパイロット噴射期間ＴＱＰＬが算出される（Ｓ２６０）。そして、前回基本噴射量指令値ＱＢＡＳＥＯＬに、今回算出された基本噴射量指令値ＱＢＡＳＥを設定する（Ｓ２７０）。こうして燃料噴射量制御処理を一旦終了する。
【０１２４】
尚、グロー通電制御処理は、イグニッションスイッチのオンが検出されるとグロープラグ２２への通電をオンして、グロープラグ２２にバッテリ６０から給電させ、このことによりグロープラグ２２の発熱を開始させる。そしてスタータ３０のオンによりディーゼルエンジン２の始動が開始し、その後、始動が完了すると、遅延時間経過後にグロープラグ２２への通電をオフするように、ＥＣＵ５２により制御されている。ここで前記遅延時間は冷却水温ＴＨＷが高ければ短くなるように制御されている。
【０１２５】
次にグロープラグ２２の断線等の異常を検出する処理について説明する。図５及び図８〜１３に該当する処理を示す。
まず、始動時前提条件算出処理（図５）について説明する。本処理はＥＣＵ５２の電源オンにより時間周期で繰り返し実行されるものである。本処理が開始されると、まず後述する始動時前提条件が未決定状態か否かが判定される（Ｓ３００）。電源オン時の初期設定状態では未決定状態とされているので（Ｓ３００で「ＹＥＳ」）、次に水温センサ３２により検出される冷却水温ＴＨＷが予め設定されている水温判定値以下か否かが判定される（Ｓ３０１）。冷却水温ＴＨＷ＞水温判定値である場合には、グロープラグ２２が正常に発熱している場合と、断線などにより発熱していない場合とでエンジン始動性に顕著な差が生じない。このためステップＳ３０４〜Ｓ３１４にて行う始動時前提条件の判定処理は高精度にできないのでステップＳ３０１では「ＮＯ」と判定する。このことにより始動時前提条件に「ＯＮ」を設定する（Ｓ３１８）。こうして一旦本処理を終了する。このことにより始動時前提条件が決定するので次の制御周期では、ステップＳ３００で「ＮＯ」と判定されるようになり、始動時前提条件算出処理（図５）の実質的な処理は終了する。又、始動時前提条件が「ＯＮ」と決定したので、後述するグロープラグ２２に対する通電（以下「グロー通電」と称する）を強制的にオン・オフするグロー異常判定が実行されることになる。
【０１２６】
一方、冷却水温ＴＨＷ≦水温判定値である場合には（Ｓ３０１で「ＹＥＳ」）、次に始動が完了したか否かが判定される（Ｓ３０２）。始動が完了していなければ（Ｓ３０２で「ＮＯ」）、このまま本処理を一旦終了する。始動が完了するまではステップＳ３０２で「ＮＯ」と判定される処理が繰り返されるのみである。この期間に、クランキングによりエンジン始動が開始されて、インジェクタ４から噴射される燃料の燃焼によりエンジン回転数ＮＥが始動完了を判定する回転数まで到達すると始動が完了する。
【０１２７】
エンジン始動が完了すると（Ｓ３０２で「ＹＥＳ」）、次に始動時間Ｔｓｔａが読み込まれる（Ｓ３０４）。この始動時間ＴｓｔａはＥＣＵ５２が別途実行する処理により、前記始動開始から始動完了までの時間をカウントした値である。
【０１２８】
次に始動開始時冷却水温度ＴＨＷｓを読み込む（Ｓ３０６）。この始動開始時冷却水温度ＴＨＷｓは、ＥＣＵ５２が別途行う処理により前記始動開始時に検出してメモリに保持しておいた冷却水温ＴＨＷである。
【０１２９】
次に標準始動時間Ｔｓｔａｎｏｒｍ（判定基準時間に相当）が算出される（Ｓ３０８）。この標準始動時間Ｔｓｔａｎｏｒｍは、グロープラグ２２が正常に発熱している場合に予想される始動時間の上限値、あるいはこの上限値から更に許容される範囲を示す始動時間である。この標準始動時間Ｔｓｔａｎｏｒｍは始動開始時冷却水温度ＴＨＷｓに応じて変化するので、例えば図６に構成を示すマップをＥＣＵ５２のＲＯＭ中に記憶しておいてステップＳ３０８にて始動開始時冷却水温度ＴＨＷｓに基づいて標準始動時間Ｔｓｔａｎｏｒｍを算出する。
【０１３０】
次に実際の始動時間Ｔｓｔａが標準始動時間Ｔｓｔａｎｏｒｍより長いか否かが判定される（Ｓ３１０）。ここでＴｓｔａ≦Ｔｓｔａｎｏｒｍであれば（Ｓ３１０で「ＮＯ」）、グロープラグ２２は正常に発熱して円滑な始動が行われたことを示しているので、後述する強制的なグロー通電オン・オフを行う異常判定処理を実行させないために始動時前提条件に「ＯＦＦ」を設定して（Ｓ３１６）、一旦本処理を終了する。このことにより始動時前提条件が決定し、次の制御周期ではステップＳ３００で「ＮＯ」と判定されるようになり、始動時前提条件算出処理（図５）の実質的な処理は終了する。このように始動時前提条件に「ＯＦＦ」が設定された状態はグロー通電の異常の可能性が無いことを表している。
【０１３１】
一方、Ｔｓｔａ＞Ｔｓｔａｎｏｒｍであれば（Ｓ３１０で「ＹＥＳ」）、次に始動時におけるバッテリ電圧ＶＢの履歴を読み込む（Ｓ３１２）。始動時、すなわち始動開始から始動完了までにおけるバッテリ電圧ＶＢは、ＥＣＵ５２により別途実行される処理により検出されている。そして同処理にて、例えば図７に示すマップにより始動開始時冷却水温度ＴＨＷｓに基づいて算出される始動時標準最低電圧Ｖｓｔａｎｏｒｍ（判定基準電圧に相当）よりも、バッテリ電圧ＶＢが低下している状態が存在したか否かが履歴としてメモリに記憶されている。この始動時標準最低電圧Ｖｓｔａｎｏｒｍは、グロープラグ２２が正常に給電されて発熱している場合に予想されるバッテリの電圧降下の程度、あるいはこの電圧降下の程度から更に許容される範囲を示す電圧値である。
【０１３２】
そしてこの履歴の内容に基づいて、始動時に実際にバッテリ電圧ＶＢが始動時標準最低電圧Ｖｓｔａｎｏｒｍより低下していたか否かが判定される（Ｓ３１４）。低下していたならば（Ｓ３１４で「ＹＥＳ」）、グロープラグ２２は正常に発熱したことを示しており、始動時間Ｔｓｔａが長いのはグロー通電の異常とは異なる別の要因によると考えられる。
【０１３３】
したがって、前述したごとく始動時前提条件に「ＯＦＦ」を設定して（Ｓ３１６）、一旦本処理を終了する。このことにより始動時前提条件が決定し、次の制御周期ではステップＳ３００で「ＮＯ」と判定されるようになり、始動時前提条件算出処理（図５）の実質的な処理は終了する。このように始動時前提条件に「ＯＦＦ」が設定された状態はグロー通電の異常の可能性が無いことを表している。
【０１３４】
一方、始動時にバッテリ電圧ＶＢが始動時標準最低電圧Ｖｓｔａｎｏｒｍより低下していなければ（Ｓ３１４で「ＮＯ」）、始動時前提条件に「ＯＮ」を設定して（Ｓ３１８）、一旦本処理を終了する。このことにより始動時前提条件が決定し、次の制御周期ではステップＳ３００で「ＮＯ」と判定されるようになり、始動時前提条件算出処理（図５）の実質的な処理は終了する。
【０１３５】
このように始動時前提条件に「ＯＮ」が設定された状態は、他の要因でステップＳ３１０で「ＹＥＳ」及びステップＳ３１４で「ＮＯ」と判定されたかもしれないが、グロー通電の異常の可能性があることを表している。
【０１３６】
次に後述する仮異常判定処理（図１０）及び本異常判定処理（図１１）を実行するための条件を判定するグロー異常判定実行条件算出処理（図８，９）について説明する。本処理は時間周期で繰り返し実行される。本処理が開始されると、まず始動時前提条件算出処理（図５）にて始動時前提条件が決定されているか否かが判定される（Ｓ４００）。始動時前提条件が「ＯＮ」又は「ＯＦＦ」に決定されていなければ（Ｓ４００で「ＮＯ」）、このまま一旦本処理を終了する。
【０１３７】
始動時前提条件算出処理（図５）にて始動時前提条件が「ＯＮ」又は「ＯＦＦ」のいずれかに決定されていれば（Ｓ４００で「ＹＥＳ」）、次に未だグロー異常判定実行許可がなされていない状態か否かが判定される（Ｓ４０２）。電源オン時の初期設定ではグロー異常判定実行許可はなされていないので、最初はステップＳ４０２では「ＹＥＳ」と判定される。
【０１３８】
そして次に判定用のセンサ類が正常か否かが判定される（Ｓ４０４）。具体的には、グロー異常判定実行許可をするか否かを判断するために、情報が必要とされる水温センサ３２、車速センサ４８及びその他のセンサ類において異常が有るか否かを判定するものである。このセンサ類の正常か否かは、例えばＥＣＵ５２が別途実行している各センサ類の異常検出処理により求められているデータを利用する。
【０１３９】
これらのセンサ類の１つでも異常なものが存在すれば（Ｓ４０４で「ＮＯ」）、このまま一旦本処理を終了する。そしてこれらセンサ類の１つでも異常である限り、正確な異常判定はできないので、グロー異常判定実行許可（Ｓ４２６）がなされることはない。
【０１４０】
該当するセンサ類が全て正常であれば（Ｓ４０４で「ＹＥＳ」）、次に水温センサ３２にて検出されている冷却水温ＴＨＷが判定基準温度範囲（例えば、０〜２０℃）に存在するか否かが判定される（Ｓ４０６）。この判定基準温度範囲はディーゼルエンジンの種類に対応して設定されているものであり、アイドル運転時にてグロープラグ２２の発熱が正常になされている時と発熱が不十分な時とで明確にエンジン運転状態に差が出る範囲でかつ異常検出に適切な範囲に設定されているものである。すなわち、判定基準温度範囲から極低温側に外れている場合では、グロー通電が異常で発熱が不十分であれば始動が困難となり運転者自身がグロー通電の異常を検知できる。又、このような極低温時ではグロープラグ２２が正常に発熱して始動できたとしても始動後のアイドル状態での燃焼が不安定となり高精度にグロー通電の異常が検出できない。更に、判定基準温度範囲から高温側に外れている場合では、グロープラグ２２が異常で発熱が不十分であっても円滑なエンジン運転が行われることから、グロー通電の異常が高精度に検出できない。
【０１４１】
冷却水温ＴＨＷが判定基準温度範囲に存在しなければ（Ｓ４０６で「ＮＯ」）、このまま一旦本処理を終了する。
一方、冷却水温ＴＨＷが判定基準温度範囲に存在すれば（Ｓ４０６で「ＹＥＳ」）、次にアクセルセンサ２６にて検出されるアクセル開度ＡＣＣＰＦが全閉（ＡＣＣＰＦ＝０％）を示しているか否かが判定される（Ｓ４０８）。アクセル開度が全閉状態でなければ（Ｓ４０８で「ＮＯ」）、すなわちアイドル運転状態でなければ噴射量が安定せず、後述する異常判定処理にて高精度に異常判定できないため、このまま一旦本処理を終了する。
【０１４２】
一方、アクセル開度が全閉状態であれば（Ｓ４０８で「ＹＥＳ」）、次に車速センサ４８にて検出される車速が「０ｋｍ／ｈ」か否かが判定される（Ｓ４１０）。車速が「０ｋｍ／ｈ」ではない場合（Ｓ４１０で「ＮＯ」）、すなわち車両が走行している場合には、アイドル運転状態でなく燃料噴射量が安定しないために後述する異常判定処理にて高精度に異常判定できないため、このまま一旦本処理を終了する。
【０１４３】
一方、車速が「０ｋｍ／ｈ」であれば（Ｓ４１０で「ＹＥＳ」）、次にバッテリ電圧ＶＢが判定基準電圧範囲内に存在するか否かが判定される（Ｓ４１２）。この判定基準電圧範囲はディーゼルエンジンの種類に対応して設定されており、正常にグロー通電されている時とグロー通電がなされていない時とで燃料噴射量に明確にエンジン運転状態に差が出る範囲に設定されている。すなわち判定基準電圧範囲よりも低電圧側に外れている場合では、オルタネータ５４の負荷が１００％に達しており、この状態でグロー通電をオン・オフ間で切り替えてもエンジン負荷変化がほとんど生じない場合があるため高精度にグロー通電の異常が検出できない。更に、判定基準電圧範囲から高電圧側に外れている場合では、オルタネータ５４の負荷が０％になっており、グロー通電をオン・オフ間で切り替えてもエンジン負荷変化がほとんど生じない場合があるため高精度にグロー通電の異常が検出できない。
【０１４４】
バッテリ電圧ＶＢが判定基準電圧範囲に存在しなければ（Ｓ４１２で「ＮＯ」）、このまま一旦本処理を終了する。
一方、バッテリ電圧ＶＢが判定基準電圧範囲に存在すれば（Ｓ４１２で「ＹＥＳ」）、次にＮＥセンサ４０にて検出されるエンジン回転数ＮＥとＥＣＵ５２が設定している目標アイドル回転数ＮＴＲＧとの偏差（｜ＮＥ−ＮＴＲＧ｜）が判定基準偏差範囲に存在するか否かが判定される（Ｓ４１４）。この判定基準偏差範囲はディーゼルエンジンの種類に対応して設定されており、アイドル回転数制御による燃料噴射量変化が大きくならない範囲を規定するものである。このことにより、後述する異常判定処理にてグロー通電のオン・オフの切り替えによる燃料噴射量の差が明確に判定できるようにされている。
【０１４５】
前記偏差（｜ＮＥ−ＮＴＲＧ｜）が判定基準偏差範囲に存在しなければ（Ｓ４１４で「ＮＯ」）、このまま一旦本処理を終了する。
一方、前記偏差（｜ＮＥ−ＮＴＲＧ｜）が判定基準偏差範囲に存在すれば（Ｓ４１４で「ＹＥＳ」）、始動完了後にエンジン安定化時間を経過したか否かが判定される（Ｓ４１６）。エンジン始動完了直後は燃料噴射量が不安定となり易い。このため、グロー通電のオン・オフの切り替えによる燃料噴射量の差が明確に判定できるように、燃料噴射量が安定化すると推定できるまでの時間、すなわちエンジン安定化時間を設定している。尚、低温時ほど安定化に時間がかかるため、冷却水温ＴＨＷが低いほどエンジン安定化時間を長くなるように、マップなどで設定しても良い。
【０１４６】
始動完了から未だエンジン安定化時間が経過していなければ（Ｓ４１６で「ＮＯ」）、燃料噴射量が安定化まで待機するために、このまま一旦本処理を終了する。
【０１４７】
その後、エンジン安定化時間が経過すれば（Ｓ４１６で「ＹＥＳ」）、次に前記グロー通電制御処理により実行されているグロー通電時間の残りが、異常判定実行可能時間以上存在するか否かが判定される（Ｓ４１８）。この異常判定実行可能時間は予め設定されており、後述する２つの異常判定処理（図１０，１１）により一旦グロー通電を強制的にオフとしてエンジン運転状態変化を検出し、更に強制的にオンに戻してエンジン運転状態変化を検出できるのに必要な時間を意味する。
【０１４８】
このステップＳ４１８の実行時点で既にグロー通電時間の残りが異常判定実行可能時間を下回っていれば（Ｓ４１８で「ＮＯ」）、このまま一旦本処理を終了する。以後、今回のトリップ内では、後述する異常判定処理（図１０，１１）は実行されることはない。
【０１４９】
一方、グロー通電時間の残りが異常判定実行可能時間以上有れば（Ｓ４１８で「ＹＥＳ」）、次に今回のトリップにおいて、既に異常判定処理（図１０，１１）により強制的なグロー通電切り替え制御が実行された履歴がないか否かが判定される（Ｓ４２０）。これは１つのトリップでは１回の異常判定処理（図１０，１１）のみ許すこととして、グローリレー２２ａの切り替えを最低限とし、グローリレー２２ａの耐久性低下を防止するためである。
【０１５０】
今回のトリップで既に異常判定処理（図１０，１１）を実施していれば（Ｓ４２０で「ＮＯ」）、今回のトリップでは、再度、異常判定処理（図１０，１１）は実行しないので、このまま一旦本処理を終了する。
【０１５１】
次に前述した始動時前提条件算出処理（図５）にて始動時前提条件が「ＯＮ」に設定されているか否かが判定される（Ｓ４２２）。ここで始動時前提条件が「ＯＦＦ」に設定されていれば（Ｓ４２２で「ＮＯ」）、次にＥＣＵ５２が記憶している前回以前のトリップで既に本異常判定が「ＯＮ」に設定されているか否かが判定される（Ｓ４２４）。以前のトリップで本異常判定が「ＯＮ」に設定されていない場合には（Ｓ４２４で「ＮＯ」）、このまま一旦本処理を終了する。
【０１５２】
一方、前回以前のトリップで既に本異常判定が「ＯＮ」に設定されている場合（Ｓ４２４で「ＹＥＳ」）には、本異常判定は「ＯＦＦ」に戻されて（Ｓ４２５）、グロー異常判定実行が許可される（Ｓ４２６）。
【０１５３】
又、始動時前提条件が「ＯＮ」に設定されている場合（Ｓ４２２で「ＹＥＳ」）には、正常判定が「ＯＦＦ」に設定されて（Ｓ４２３）からグロー異常判定実行が許可される（Ｓ４２６）。すなわちステップＳ４２２で「ＹＥＳ」と判定された場合は、前述した始動時前提条件算出処理（図５）にて異常可能性が有る（Ｓ３１４で「ＮＯ」）とされたか、あるいは異常可能性の判定自体ができなかった（Ｓ３０１で「ＮＯ」）場合である。したがって後述する異常判定処理（図１０，１１）を実行して異常有無を判定することになる。
【０１５４】
又、ステップＳ４２４で「ＹＥＳ」と判定された場合には、前回以前のトリップでグロー通電に異常が存在していることが判明したため既に修理が完了している可能性がある。このため始動時前提条件算出処理（図５）にて異常可能性が無い（Ｓ３１６）とされても、後述する異常判定処理（図１０，１１）を実行して修理により正常な状態になったか否かを情報として残す処理を行う。
【０１５５】
次に強制的にグロー通電の切り替えを行う異常判定処理（図１０，１１）について説明する。図１０は仮異常判定処理、図１１は本異常判定処理を表し、これらの処理は時間周期で繰り返し実行される。
【０１５６】
仮異常判定処理（図１０）が開始されると、まず前述したグロー異常判定実行条件算出処理（図８，９）のステップＳ４２６によりグロー異常判定実行の許可がなされているか否かが判定される（Ｓ５００）。未だグロー異常判定実行の許可がなされていなければ（Ｓ５００で「ＮＯ」）、このまま一旦本処理を終了し、実質的な処理はなされない。
【０１５７】
グロー異常判定実行の許可がなされていれば（Ｓ５００で「ＹＥＳ」）、次にグロー異常判定実行の許可がなされて最初の処理か否かが判定される（Ｓ５０２）。最初の処理で有れば（Ｓ５０２で「ＹＥＳ」）、次にこの時の目標アイドル回転数ＮＴＲＧがグローオフ直前目標アイドル回転数ＮＴｏｌｄとしてメモリに記憶される（Ｓ５０４）。これは後述するグロー異常判定停止条件算出処理（図１２）にて目標アイドル回転数ＮＴＲＧの変化有無判定に用いられる。
【０１５８】
次に、この時の最終基本噴射量指令値ＱＦＩＮＣ（図４：Ｓ２３０）がグローオフ直前最終基本噴射量指令値Ｑｏｌｄ１としてメモリに記憶される（Ｓ５０６）。そして、この時のバッテリ電圧ＶＢがグローオフ直前バッテリ電圧ＶＢｏｌｄ１としてメモリに記憶される（Ｓ５０８）。
【０１５９】
そしてイグニッションスイッチ・オンから現在まで継続しているグロー通電を強制的にオフする（Ｓ５１０）。このことにより直前までグロー通電されていた分の電気エネルギーが消失し、電気エネルギー全体の消費が大きく低下する。このため電気エネルギー消費低減に対応してディーゼルエンジン２に対する負荷が低下する。したがって前記燃料噴射量制御処理（図３，４）の一部で実行しているアイドル回転数制御においては、同一の目標アイドル回転数ＮＴＲＧを維持するために最終基本噴射量指令値ＱＦＩＮＣが低下される。又、バッテリ電圧ＶＢもグロープラグ２２への通電停止により上昇する。
【０１６０】
次に上述したディーゼルエンジン２に対する負荷が正常に低下したことを判定するために、アイドル回転数制御下での最終基本噴射量指令値ＱＦＩＮＣの変化と、バッテリ電圧ＶＢの変化を判定する。
【０１６１】
まず次式６を満足した状態がエンジン負荷低下を判定するに必要な時間継続したか否かが判定される（Ｓ５１２）。
【０１６２】
【数６】
Ｑｏｌｄ１ − ＱＦＩＮＣ ≧ ｄＱ１ … ［式６］
ここで低下判定値ｄＱ１は、電気エネルギー消費低減に対応した燃料噴射量低下分の最低限の値を予め実験等により求めて設定したものである。
【０１６３】
前記式６を満足していない場合や、前記式６を満足してもエンジン負荷低下判定に必要な時間継続していない場合には（Ｓ５１２で「ＮＯ」）、次式７を満足した状態がバッテリ電圧ＶＢの上昇を判定するに必要な時間継続したか否かが判定される（Ｓ５１４）。
【０１６４】
【数７】
ＶＢ − ＶＢｏｌｄ１ ≧ ｄＶ１ … ［式７］
ここで上昇判定値ｄＶ１は、グロー通電オフに対応したバッテリ電圧ＶＢの上昇の最低限の値を予め実験等により求めて設定したものである。
【０１６５】
前記式７を満足していない場合や、前記式７を満足しても電圧上昇判定に必要な時間継続していない場合には（Ｓ５１４で「ＮＯ」）、次式８を満足した状態がエンジン負荷の無変化状態を判定するに必要な時間継続したか否かが判定される（Ｓ５１６）。
【０１６６】
【数８】
Ｑｏｌｄ１ − ＱＦＩＮＣ ＜ ｄＱ１ … ［式８］
この式８は前記式６が満足されていない状態を表している。
【０１６７】
前記式８を満足していない場合や、前記式８を満足してもエンジン負荷の無変化判定に必要な時間継続していない場合には（Ｓ５１６で「ＮＯ」）、このまま一旦本処理を終了する。
【０１６８】
前記式６を満足した状態がエンジン負荷低下を判定するに必要な時間継続した場合（Ｓ５１２で「ＹＥＳ」）、又は前記式７を満足した状態がバッテリ電圧ＶＢの上昇を判定するに必要な時間継続した場合（Ｓ５１４で「ＹＥＳ」）には、正常判定は「ＯＮ」に設定される（Ｓ５１８）。すなわちステップＳ５１２又はステップＳ５１４にて「ＹＥＳ」と判定される状態は、強制的なグロー通電オフ（Ｓ５１０）の前には、正常にグロー通電が実行されており、ステップＳ５１０にてＥＣＵ５２の指令通りにグロー通電がオフとなったことを示している。したがって正常判定「ＯＮ」との情報がＥＣＵ５２内のバックアップＲＡＭに記憶される。こうして一旦本処理を終了する。尚、正常判定が「ＯＮ」となれば、後述するグロー異常判定停止条件算出処理（図１２，１３）により、再度、グロー通電はオンに戻されるとともに、本異常判定処理（図１１）は実行されない。
【０１６９】
一方、ステップＳ５１２もステップＳ５１４も共に満足されない内に、前記式８を満足した状態がエンジン負荷の無変化状態を判定するに必要な時間継続した場合（Ｓ５１６で「ＹＥＳ」）、仮異常判定は「ＯＮ」に設定される（Ｓ５２０）。すなわち強制的なグロー通電オフ（Ｓ５１０）の前には、正常にグロー通電がオンされていないか、あるいはステップＳ５１０でのＥＣＵ５２の指令通りにグロー通電がオフとならなかったことを示している。したがって仮異常判定「ＯＮ」との情報がＥＣＵ５２内のバックアップＲＡＭに記憶される。こうして一旦本処理を終了する。このように仮異常判定「ＯＮ」とされたことにより、後述するグロー異常判定停止条件算出処理（図１２，１３）により、仮異常判定処理（図１０）は停止されるとともに、本異常判定処理（図１１）の実質的な処理が実行されるようになる。
【０１７０】
本異常判定処理（図１１）について説明する。本処理は時間周期で繰り返し実行される。本処理が開始されると、まず仮異常判定が「ＯＮ」か否かが判定される（Ｓ６００）。前述した仮異常判定処理（図１０）にて仮異常判定が「ＯＮ」と設定されるまでは、初期設定にて設定された仮異常判定「ＯＦＦ」の状態が継続しているので（Ｓ６００で「ＮＯ」）、このまま一旦本処理を終了し、実質的な処理はなされない。
【０１７１】
しかし、前述したごとく仮異常判定処理（図１０）にて仮異常判定が「ＯＮ」に設定されると（Ｓ６００で「ＹＥＳ」）、次に仮異常判定処理（図１０）のステップＳ５１０での強制的グロー通電「ＯＦＦ」から待機時間が経過したか否かが判定される（Ｓ６０１）。この待機時間は、短時間にグローリレー２２ａのオンオフ間の切り替えが行われるのを防止して、グローリレー２２ａの耐久性低下を防止するために予め設けられている。この待機時間は、グローリレー２２ａの種類や電流量によっても異なるが、例えば１００ｍｓｅｃの時間が設定されている。
【０１７２】
待機時間が経過していない間は（Ｓ６０１で「ＮＯ」）、このまま一旦本処理を終了し、本異常判定処理での実質的処理は開始されない。
待機時間が経過すると（Ｓ６０１で「ＹＥＳ」）、次にステップＳ６０１にて「ＹＥＳ」と判定されてから最初の処理か否かが判定される（Ｓ６０２）。最初の処理で有れば（Ｓ６０２で「ＹＥＳ」）、次にこの時の最終基本噴射量指令値ＱＦＩＮＣがグローオン直前最終基本噴射量指令値Ｑｏｌｄ２としてメモリに記憶される（Ｓ６０４）。そして、この時のバッテリ電圧ＶＢがグローオン直前バッテリ電圧ＶＢｏｌｄ２としてメモリに記憶される（Ｓ６０６）。
【０１７３】
そしてグロー通電停止状態から強制的に通電をオンする（Ｓ６０８）。このことによりグロー通電が再開されて電気エネルギーの消費が大きく上昇する。このため電気エネルギー消費上昇に対応してディーゼルエンジン２に対するエンジン負荷が上昇する。したがって前記燃料噴射量制御処理（図３，４）の一部で実行しているアイドル回転数制御においては、同一の目標アイドル回転数ＮＴＲＧを維持するために最終基本噴射量指令値ＱＦＩＮＣが上げられる。又、バッテリ電圧ＶＢもグロープラグ２２への通電開始により降下する。
【０１７４】
次にエンジン負荷が正常に上昇したことを判定するために、アイドル回転数制御下での最終基本噴射量指令値ＱＦＩＮＣの変化と、バッテリ電圧ＶＢの変化を判定する。
【０１７５】
まず次式９を満足した状態がエンジン負荷の上昇を判定するに必要な時間継続したか否かが判定される（Ｓ６１０）。
【０１７６】
【数９】
ＱＦＩＮＣ − Ｑｏｌｄ２ ≧ ｄＱ２ … ［式９］
ここで上昇判定値ｄＱ２は、電気エネルギー消費増加に対応した燃料噴射量上昇分の最低限の値を予め実験等により求めて設定したものである。
【０１７７】
前記式９を満足していない場合や、前記式９を満足してもエンジン負荷上昇判定に必要な時間継続していない場合には（Ｓ６１０で「ＮＯ」）、次式１０を満足した状態がバッテリ電圧ＶＢの降下を判定するに必要な時間継続したか否かが判定される（Ｓ６１２）。
【０１７８】
【数１０】
ＶＢｏｌｄ２ − ＶＢ ≧ ｄＶ２ … ［式１０］
ここで降下判定値ｄＶ２は、グロー通電オンに対応したバッテリ電圧ＶＢ降下の最低限の値を予め実験等により求めて設定したものである。
【０１７９】
前記式１０を満足していない場合や、前記式１０を満足しても電圧降下判定に必要な時間継続していない場合には（Ｓ６１２で「ＮＯ」）、次式１１を満足した状態がエンジン負荷の無変化状態を判定するに必要な時間継続したか否かが判定される（Ｓ６１４）。
【０１８０】
【数１１】
ＱＦＩＮＣ − Ｑｏｌｄ２ ＜ ｄＱ２ … ［式１１］
この式１１は前記式９が満足されていない状態を表している。
【０１８１】
前記式１１を満足していない場合や、前記式１１を満足してもエンジン負荷の無変化判定に必要な時間継続していない場合には（Ｓ６１４で「ＮＯ」）、このまま一旦本処理を終了する。
【０１８２】
前記式９を満足した状態がエンジン負荷上昇を判定するに必要な時間継続した場合（Ｓ６１０で「ＹＥＳ」）、又は前記式１０を満足した状態がバッテリ電圧ＶＢの降下を判定するに必要な時間継続した場合（Ｓ６１２で「ＹＥＳ」）には、仮異常判定は「ＯＦＦ」に戻される（Ｓ６１６）。すなわちステップＳ６１０又はステップＳ６１２にて「ＹＥＳ」と判定される状態は、強制的なグロー通電オン（Ｓ６０８）の前にグロー通電が確かにオフとなっており、ステップＳ６０８でのＥＣＵ５２の指令通りにグロー通電がオンとなったことを示している。このことは仮異常判定処理（図１０）では何らかの原因によりグロー通電が実際にオフされたのにもかかわらず、通電オフが明確に検出されなかったことを示しており、今回の本異常判定処理（図１１）にてグロープラグ２２が正常に機能していることが確認されたことを示している。
【０１８３】
したがって仮異常判定は「ＯＦＦ」に戻されてＥＣＵ５２内のバックアップＲＡＭに記憶される。こうして一旦本処理を終了する。以後の制御周期では、仮異常判定「ＯＦＦ」となることにより、ステップＳ６００にて「ＮＯ」と判定されるようになるので、本異常判定処理（図１１）の実質的処理は終了する。尚、グロー通電はオンに戻されているので、イグニッションスイッチ・オンにより開始された前記グロー通電制御処理によるグロー通電時間の残り分の時間の通電が継続した後、グロー通電はオフされる。
【０１８４】
一方、ステップＳ６１０もステップＳ６１２も共に満足されない内に、前記式１１を満足した状態がエンジン負荷の無変化状態を判定するに必要な時間継続した場合（Ｓ６１４で「ＹＥＳ」）、本異常判定が「ＯＮ」に設定される（Ｓ６１８）。すなわち前記仮異常判定処理（図１０）における異常であるとの判定（仮異常判定）とともに、本異常判定処理（図１１）にても異常であるとの判定がなされたことを示している。したがってグロー通電が異常であることに高い確実性が存在するので、本異常判定「ＯＮ」との情報がＥＣＵ５２内のバックアップＲＡＭに記憶される。こうして一旦本処理を終了する。このように本異常判定「ＯＮ」とされたことにより、後述するグロー異常判定停止条件算出処理（図１２，１３）により本異常判定処理（図１１）が停止される。
【０１８５】
グロー異常判定停止条件算出処理（図１２，１３）について説明する。本処理は時間周期で繰り返し実行され、前記仮異常判定処理（図１０）及び前記本異常判定処理（図１１）を停止するために実行される。
【０１８６】
本処理が開始されると、まず前述したグロー異常判定実行条件算出処理（図８，９）のステップＳ４２６によるグロー異常判定実行の許可がなされているか否かが判定される（Ｓ７００）。未だグロー異常判定実行の許可がなされていなければ（Ｓ７００で「ＮＯ」）、このまま一旦本処理を終了し、実質的な処理はなされない。
【０１８７】
グロー異常判定実行の許可がなされていれば（Ｓ７００で「ＹＥＳ」）、前述したグロー異常判定実行条件算出処理（図８，９）のステップＳ４０４〜Ｓ４１２と同じ処理（Ｓ７０２〜Ｓ７１０）が行われる。すなわち判定用センサ類が正常か否かが判定される（Ｓ７０２）。判定用センサ類が正常であれば（Ｓ７０２で「ＹＥＳ」）、冷却水温ＴＨＷが判定基準温度範囲に存在するか否かが判定される（Ｓ７０４）。冷却水温ＴＨＷが判定基準温度範囲に存在すれば（Ｓ７０４で「ＹＥＳ」）、アクセル開度ＡＣＣＰＦが全閉か否かが判定される（Ｓ７０６）。アクセル開度ＡＣＣＰＦが全閉であれば（Ｓ７０６で「ＹＥＳ」）、車速が「０ｋｍ／ｈ」か否かが判定される（Ｓ７０８）。車速が「０ｋｍ／ｈ」であれば（Ｓ７０８で「ＹＥＳ」）、バッテリ電圧ＶＢが判定基準電圧範囲に存在するか否かが判定される（Ｓ７１０）。
【０１８８】
そしてバッテリ電圧ＶＢが判定基準電圧範囲に存在すれば（Ｓ７１０で「ＹＥＳ」）、仮異常判定処理（図１０）及び本異常判定処理（図１１）の実行時において、アイドル回転数制御において目標アイドル回転数ＮＴＲＧに変化が無いか否かが判定される（Ｓ７１２）。この変化は、現在の目標アイドル回転数ＮＴＲＧを、前記仮異常判定処理（図１０）のステップＳ５０４で記憶しているグローオフ直前目標アイドル回転数ＮＴｏｌｄと比較することにより行われる。
【０１８９】
目標アイドル回転数ＮＴＲＧが変化すると最終基本噴射量指令値ＱＦＩＮＣの変動が生じて、グロー通電のオン・オフ切り替えによる噴射量変動との区別が困難となる。したがって、この判定は、仮異常判定処理（図１０）及び本異常判定処理（図１１）において誤判定を防止するために実行している。
【０１９０】
目標アイドル回転数ＮＴＲＧに変化が無ければ（Ｓ７１２で「ＹＥＳ」）、正常判定と本異常判定とが共に「ＯＦＦ」に設定されているか否かが判定される（Ｓ７１４）。ここで正常判定と本異常判定とが共に「ＯＦＦ」であれば（Ｓ７１４で「ＹＥＳ」）、次にバッテリ６０を電源とする各種装置のスイッチに変化が無いか否かが判定される（Ｓ７１６）。これらのスイッチはエアコンスイッチ５０、電気ヒータスイッチ、テールランプスイッチ、デフォッガスイッチ、ブレーキシグナルスイッチ等である。これらのスイッチに変化が有るとバッテリ電圧ＶＢや最終基本噴射量指令値ＱＦＩＮＣに変動が生じて、グロー通電のオン・オフ切り替えによる変動との区別が困難となる。したがって、この判定は、仮異常判定処理（図１０）及び本異常判定処理（図１１）において誤判定を防止するために実行している。
【０１９１】
前記各種スイッチに変化が無い場合には（Ｓ７１６で「ＹＥＳ」）、次に仮異常判定「ＯＦＦ」か否かが判定される（Ｓ７１８）。ここで、前記仮異常判定処理（図１０）が実行中であって正常判定「ＯＦＦ」であるとともに仮異常判定「ＯＦＦ」である状態では（Ｓ７１８で「ＹＥＳ」）、このまま一旦本処理を終了する。
【０１９２】
一方、上述したステップＳ７０２〜７１６のいずれか１つでも「ＮＯ」と判定されると、仮異常判定は「ＯＦＦ」に設定される（Ｓ７２０）。このことにより本異常判定処理（図１１）では、ステップＳ６００にて「ＮＯ」と判定されるようになるので実質的な処理は終了する。
【０１９３】
そして、次にグロー通電が、仮異常判定処理（図１０）のステップＳ５１０の実行によりオンからオフに切り替わってから待機時間が経過した後に次にグロー通電オンとする強制的通電オン処理が実行される（Ｓ７２２）。この待機時間は、グローリレー２２ａの耐久性の低下を防止するために、前記本異常判定処理（図１１）のステップＳ６０１にて説明した待機時間と同じ時間が用いられる。
【０１９４】
この強制的グロー通電オン処理では、ステップＳ７２２の実行の時点で既に待機時間を経過していれば、直ちにグロー通電がなされる。又、ステップＳ７２２の実行の時点で未だ待機時間を経過していなければ、待機時間の経過後にグロー通電がなされる。尚、本異常判定（図１１）のステップＳ６０８にて強制的グロー通電オンが既に実行されていればグロー通電オン状態が維持される。
【０１９５】
そして、次にグロー異常判定実行が不許可となって（Ｓ７２４）、本処理を一旦終了する。
次に制御周期ではグロー異常判定実行許可が取り消されたので、グロー異常判定停止条件算出処理（図１２，１３）ではステップＳ７００にて「ＮＯ」と判定されて実質的な処理は行われなくなる。同様に仮異常判定処理（図１０）が実行されていても、ステップＳ５００にて「ＮＯ」と判定されて実質的な処理は行われなくなる。
【０１９６】
尚、前記ステップＳ７１４で「ＮＯ」と判定される場合は、仮異常判定処理（図１０）のステップＳ５１８が実行されて正常判定「ＯＮ」となった場合あるいは本異常判定（図１１）のステップＳ６１８が実行されて本異常判定「ＯＮ」となった場合である。
【０１９７】
又、前述したごとく仮異常判定処理（図１０）のステップＳ５２０が実行されて仮異常判定「ＯＮ」となった場合には（Ｓ７１８で「ＮＯ」）、仮異常判定処理（図１０）の実行が停止される（Ｓ７２６）。
【０１９８】
上述した本実施の形態における処理の一例を図１４〜１８のタイミングチャートに示す。
図１４は始動時前提条件が「ＯＦＦ」であった場合を示している。ここでは時刻ｔ０にてイグニッションスイッチを「ＯＮ」としている。このことにより直ちにグロー通電オンとされる。そして時刻ｔ１にてインジケータランプにより運転者にスタータ許可の表示がなされることにより、直ちに運転者はスタータ３０を「ＯＮ」させ、このことにより始動モードが開始される。そしてエンジン回転数ＮＥが始動完了を示す回転数まで上昇することにより始動完了がＥＣＵ５２により判定される（ｔ２）。この時に得られた実際の始動時間Ｔｓｔａ（ｔ１〜ｔ２）は標準始動時間Ｔｓｔａｎｏｒｍ以下である。尚、図１４の例ではバッテリ電圧ＶＢについても始動時標準最低電圧Ｖｓｔａｎｏｒｍよりも低下している履歴がある。
【０１９９】
このため始動完了後に、始動時前提条件算出処理（図５）のステップＳ３１０にて「ＮＯ」と判定されて、前提条件としては「ＯＦＦ」が設定される（Ｓ３１６）。したがって、以後、仮異常判定処理（図１０）も本異常判定処理（図１１）も実行されることはなく、グロー通電オン状態は継続して、通常のグロー通電制御にて設定されている通電時間が終了すると（ｔ３）、グロー通電はオフとされる。上述した処理により始動時前提条件＝「ＯＦＦ」、本異常判定＝「ＯＦＦ」、正常判定＝「ＯＦＦ」が、ダイアグノーシスなどの内部情報としてＥＣＵ５２のメモリに記録されることになる。
【０２００】
図１５の例は、グロー通電「ＯＮ」にしても、断線により全くグロープラグ２２に電流が流れない場合を示している。イグニッションスイッチを「ＯＮ」し（ｔ１０）、スタータ許可によりスタータ３０が駆動開始し（ｔ１１）、エンジン始動が完了する（ｔ１２）。この時、実際の始動時間Ｔｓｔａは標準始動時間Ｔｓｔａｎｏｒｍより長くなり、バッテリ電圧ＶＢは始動時標準最低電圧Ｖｓｔａｎｏｒｍよりも低下した履歴がない。このため始動時前提条件算出処理（図５）のステップＳ３１０にて「ＹＥＳ」、ステップＳ３１４にて「ＮＯ」と判定されて、始動時前提条件としては「ＯＮ」が設定される（Ｓ３１８）。このことによりグロー異常判定実行条件算出処理（図８，９）が実行される。そしてグロー異常判定実行が許可されると（Ｓ４２６）、仮異常判定処理（図１０）が実行される（ｔ１３）。このことによりグロー通電が強制的にオフに駆動される。この強制的グロー通電オフ直後に、図１５の例では、判定のために待機しても燃料噴射量もバッテリ電圧も共に変化がないため（Ｓ５１６で「ＹＥＳ」）、仮異常判定は「ＯＮ」に設定される（Ｓ５２０：ｔ１４）。したがってグロー異常判定停止条件算出処理（図１２，１３）のステップＳ７２６により仮異常判定処理（図１０）は停止し、代わりに本異常判定処理（図１１）の実質的な処理が開始され、強制的にグロー通電がオンに駆動される（Ｓ６０８）。図１５の例では、この強制的グロー通電オン直後においても、判定のために待機しても燃料噴射量もバッテリ電圧も共に変化がないため（Ｓ６１４で「ＹＥＳ」）、本異常判定は「ＯＮ」に設定される（Ｓ６１８：ｔ１５）。そしてグロー異常判定停止条件算出処理（図１２，１３）のステップＳ７１４では「ＮＯ」と判定されることで、仮異常判定は「ＯＦＦ」となり（Ｓ７２０）、グロー異常判定実行は不許可となる（Ｓ７２４）。ステップＳ７２２では、既に強制的グロー通電はオンとなっているのでオン状態を維持する。
【０２０１】
その後、通常のグロー通電制御にて設定されている通電時間が終了すると（ｔ１６）、グロー通電はオフに駆動される。上述した処理により始動時前提条件＝「ＯＮ」、本異常判定＝「ＯＮ」、正常判定＝「ＯＦＦ」がＥＣＵ５２のメモリに記録されることになる。
【０２０２】
図１６の例は、仮異常判定処理（図１０）にて正常であると判定された例を示している。イグニッションスイッチをオンし（ｔ２０）、スタータ許可によりスタータ３０が駆動開始し（ｔ２１）、エンジン始動が完了する（ｔ２２）。この時、実際の始動時間Ｔｓｔａは標準始動時間Ｔｓｔａｎｏｒｍより長く、バッテリ電圧ＶＢは始動時標準最低電圧Ｖｓｔａｎｏｒｍよりも低下した履歴がない。このため始動時前提条件算出処理（図５）のステップＳ３１０にて「ＹＥＳ」、ステップＳ３１４にて「ＮＯ」と判定されて、前提条件としては「ＯＮ」が設定される（Ｓ３１８）。したがって、グロー異常判定実行条件算出処理（図８，９）が実行されて、グロー異常判定実行が許可されると（Ｓ４２６）、仮異常判定処理（図１０）が実行される（ｔ２３）。このことによりグロー通電が強制的に「ＯＦＦ」に駆動される。この時、図１６の例では、直ちにバッテリ電圧ＶＢが上昇判定値ｄＶ１以上上昇してステップＳ５１４にて「ＹＥＳ」と判定される。尚、燃料噴射量についても低下判定値ｄＱ１以上低下している。
【０２０３】
このため正常判定が「ＯＮ」に設定される（Ｓ５１８：ｔ２４）。したがって仮異常判定は「ＯＦＦ」に維持され（Ｓ７２０）、グロー異常判定実行は不許可となり（Ｓ７２４）、仮異常判定処理（図１０）は停止する。更にステップＳ７２２の処理により強制的なグロー通電オフ（Ｓ５１０）から待機時間経過後にグロー通電オンに戻される（ｔ２５）。このため本異常判定処理（図１１）は実行されない。その後、通常のグロー通電制御にて設定されている通電時間が終了すると（ｔ２６）、グロー通電はオフとされる。上述した処理により始動時前提条件＝「ＯＮ」、本異常判定＝「ＯＦＦ」、正常判定＝「ＯＮ」がＥＣＵ５２のメモリに記録されることになる。
【０２０４】
図１７に、仮異常判定処理（図１０）での強制的グロー通電オフでは燃料噴射量及びバッテリ電圧の変化が十分に生じず、本異常判定処理（図１１）の強制的グロー通電オンにて初めて燃料噴射量及びバッテリ電圧の変化が十分に生じた例を示す。時刻ｔ３０〜ｔ３４までは前記図１５にて説明した時刻ｔ１０〜ｔ１４までと同様に推移する。そして時刻ｔ３４にて開始された本異常判定処理（図１１）にて強制的にグロー通電がオンに駆動される（Ｓ６０８）。この時、図１７の例では、先に燃料噴射量が上昇判定値ｄＱ２以上の上昇を示したので（Ｓ６１０で「ＹＥＳ」）、仮異常判定は「ＯＦＦ」に戻される（Ｓ６１６：ｔ３５）。その後、通常のグロー通電制御にて設定されている通電時間が終了すると（ｔ３６）、グロー通電は「ＯＦＦ」とされる。上述した処理により始動時前提条件＝「ＯＮ」、本異常判定＝「ＯＦＦ」、正常判定＝「ＯＦＦ」がＥＣＵ５２のメモリに記録されることになる。尚、適当なタイミング、例えばアクセルペダル２４を踏み込んだりした場合（Ｓ７０６で「ＮＯ」）に、グロー異常判定実行は不許可となる（Ｓ７２４）。
【０２０５】
図１８に、前回以前のトリップにてグロー通電の異常が判明し、修理が完了された直後のエンジン始動時についての例を表す。時刻ｔ４０〜ｔ４２までは前記図１４にて説明した時刻ｔ０〜ｔ２までと同様に推移し、始動時前提条件算出処理（図５）では正常にグロー通電がなされるのでステップＳ３１０で「ＮＯ」又はステップＳ３１４で「ＹＥＳ」と判定されて、始動時前提条件は「ＯＦＦ」に設定される（Ｓ３１６）。
【０２０６】
そして時刻ｔ４３で、グロー異常判定実行条件算出処理（図８，９）においてステップＳ４００〜Ｓ４２０にてすべて「ＹＥＳ」と判定されると、次に始動時前提条件が「ＯＮ」か否かが判定される（Ｓ４２２）。この時、グロープラグ２２に異常の可能性が無いとして、始動時前提条件には「ＯＦＦ」が設定されているので（Ｓ４２２で「ＮＯ」）、次に既に本異常判定が「ＯＮ」に設定されているか否かが判定される（Ｓ４２４）。ここでは既に本異常判定は「ＯＮ」となっているので（Ｓ４２４で「ＹＥＳ」）、次に本異常判定は「ＯＦＦ」に戻される（Ｓ４２５）。そしてグロー異常判定実行が許可され（Ｓ４２６）、このことにより仮異常判定処理（図１０）の実質的な処理が開始される。
【０２０７】
そして仮異常判定処理（図１０）では、グロー通電が強制的にオフに駆動される。この時、グロー通電は正常にオフとなるので、直ちにバッテリ電圧ＶＢが上昇判定値ｄＶ１以上上昇してステップＳ５１４にて「ＹＥＳ」と判定される（ｔ４４）。尚、燃料噴射量についても低下判定値ｄＱ１以上低下している。
【０２０８】
このため正常判定が「ＯＮ」に設定される（Ｓ５１８）。したがってステップＳ７１４では「ＮＯ」と判定されて、仮異常判定は「ＯＦＦ」を維持し（Ｓ７２０）、グロー異常判定実行は不許可となり（Ｓ７２４）、仮異常判定処理（図１０）は停止する。更にステップＳ７２２の処理により、強制的なグロー通電オフ（Ｓ５１０）から待機時間経過後にグロー通電オンに戻される（ｔ４５）。
【０２０９】
その後、通常のグロー通電制御にて設定されている通電時間が終了すると（ｔ４６）、グロー通電はオフとされる。上述した処理により始動時前提条件＝「ＯＦＦ」、本異常判定＝「ＯＦＦ」、正常判定＝「ＯＮ」がＥＣＵ５２のメモリに記録されることになる。
【０２１０】
上述した構成において、始動時前提条件算出処理（図５）が異常可能性判定手段としての処理に、グロー異常判定実行条件算出処理（図８，９）、仮異常判定処理（図１０）、本異常判定処理（図１１）及びグロー異常判定停止条件算出処理（図１２，１３）が異常有無判定手段としての処理に相当する。又、始動開始から始動完了までの時間をカウントして始動時間Ｔｓｔａを求める処理、及び始動開始から始動完了までにおけるバッテリ電圧ＶＢの履歴を検出しておく処理が始動完了前状態検出手段としての処理に相当する。又、グロー異常判定実行条件算出処理（図８，９）及び仮異常判定処理（図１０）が第１異常判定手段としての処理に、本異常判定処理（図１１）及びグロー異常判定停止条件算出処理（図１２，１３）が第２異常判定手段としての処理に相当する。
【０２１１】
以上説明した本実施の形態１によれば、以下の効果が得られる。
（イ）．始動時前提条件算出処理（図５）が行う異常可能性判定、すなわちグロー通電の強制的オン又はオフによらずに始動時間Ｔｓｔａの長さや始動時におけるバッテリ電圧ＶＢの状態に基づいて行う異常検出は、グロー通電の強制的変化を行う場合に比較して確実性が低い。これはグロープラグ２２に対して正常に通電がなされていても、他の原因で始動時間Ｔｓｔａが長くなったり、バッテリ電圧ＶＢが低下していない場合があるからである。
【０２１２】
しかしグロー通電の強制的変化がなされなくても、グロー通電がオン操作されている場合に始動時間Ｔｓｔａが十分に短かければ、あるいはバッテリ電圧ＶＢが十分に低下していればグロー通電の異常可能性が無いことは確実性高く判定できる。したがって始動時前提条件算出処理（図５）を、仮異常判定処理（図１０）や本異常判定処理（図１１）の前に実行することで、異常の可能性が無いと判定された場合には、仮異常判定処理（図１０）や本異常判定処理（図１１）を実行する必要が無くなる。始動時前提条件算出処理（図５）により異常の可能性が無いとはいえない判定、すなわち異常の可能性有りと判定された場合に、強制的なグロー通電オン・オフを実行する仮異常判定処理（図１０）や本異常判定処理（図１１）を実行すれば良い。したがってグローリレー２２ａの駆動によるグロー通電の強制的変化回数を抑制できる。
【０２１３】
このようにして異常の可能性有りと判定された場合に強制的なグロー通電オン・オフを実行して燃料噴射量変化やバッテリ電圧変化を捉えることで、グロー通電異常判定の正確さを確保できるとともに、このようなグロー通電の切り替え回数を少なくできるのでグローリレー２２ａの耐久性の低下も抑制できる。
【０２１４】
（ロ）．グロー通電が正常に行われれば、エンジン始動は早期に完了するので、始動時間Ｔｓｔａは短くなる。しかしグロー通電が正常でなければ始動時間Ｔｓｔａは長くなる。したがって始動時前提条件算出処理（図５）では、始動時間Ｔｓｔａが標準始動時間Ｔｓｔａｎｏｒｍ以下であればグロープラグ２２の異常可能性は無いと判定できる。逆に始動時間Ｔｓｔａが標準始動時間Ｔｓｔａｎｏｒｍより長ければ、他に原因が有るかもしれないが、グロープラグ２２が異常である可能性も否定できない。
【０２１５】
又、始動時においてグロー通電が正常になされていれば始動完了前においてバッテリ電圧ＶＢは降下しており、グロー通電がなされていなかったり通電量が異常に低かったりした場合にはバッテリ電圧ＶＢの降下はほとんど無い。したがって始動時前提条件算出処理（図５）では、始動完了前にバッテリ電圧ＶＢが始動時標準最低電圧Ｖｓｔａｎｏｒｍよりも低下した履歴が始動時にあればグロープラグ２２の異常可能性は無いと判定できる。逆に始動完了前にバッテリ電圧ＶＢが始動時標準最低電圧Ｖｓｔａｎｏｒｍより降下した履歴が無ければ、他に原因が有るかもしれないが、グロープラグ２２が異常である可能性も否定できない。
【０２１６】
したがって始動時間Ｔｓｔａが標準始動時間Ｔｓｔａｎｏｒｍより長い状態で有り、かつ始動完了前にバッテリ電圧ＶＢが始動時標準最低電圧Ｖｓｔａｎｏｒｍより降下した履歴が無ければ、異常可能性有りと判定する。
【０２１７】
このようにして始動時前提条件算出処理（図５）ではグロー通電の強制的変化をさせなくても異常可能性の有無を容易に判定できる。しかも標準始動時間Ｔｓｔａｎｏｒｍ及び始動時標準最低電圧Ｖｓｔａｎｏｒｍは、始動開始時冷却水温度ＴＨＷｓに基づいて設定されているので、より確実に異常可能性の有無を判定できる。
【０２１８】
（ハ）．グロー異常判定実行条件算出処理（図８，９）では、通常のグロー通電制御にて設定されたグロー通電時間の残りが、仮異常判定処理（図１０）及び本異常判定処理（図１１）を実行できる長さである場合に限って（Ｓ４１８で「ＹＥＳ」）、グロー異常判定実行を許可している。
【０２１９】
このことにより仮異常判定処理（図１０）及び本異常判定処理（図１１）は、通常のグロー通電オンの設定時間内で、グロー通電の強制的変化に伴う異常有無判定を完了できることになる。このためグロー通電の強制的変化によってグロー通電制御が徒に延長されることがなく、異常有無判定によるエネルギー消費を抑制することができる。
【０２２０】
尚、このように仮異常判定処理（図１０）及び本異常判定処理（図１１）による強制的グロー通電変化は、通常のグロー通電時に行われる。しかし、グロー異常判定実行条件算出処理（図８，９）により特にエンジン運転状態が安定した後に強制的グロー通電変化が行われるので、始動後のエンジン運転の安定性には問題を生じない。
【０２２１】
（ニ）．上述したごとく仮異常判定処理（図１０）及び本異常判定処理（図１１）により、グロー通電異常を強制的グロー通電オフと強制的グロー通電オンとの２段階にて確認しており確実な異常判定ができる。しかもこの２段階の強制的通電切り替えにより、グロー通電状態は元のグロー通電オン状態に戻すことができ、ディーゼルエンジンの運転安定性を阻害しない。
【０２２２】
（ホ）．通電オフと通電オンとを短時間間隔で実行すると、グローリレー２２ａの耐久性が低下する可能性がある。このため本異常判定処理（図１１）では、仮異常判定処理（図１０）での強制的グロー通電オフ（Ｓ５１０）の時点からグローリレー２２ａ保護のための待機時間が経過するまで強制的グロー通電オンは実行していない（Ｓ６０１）。このことによりグローリレー２２ａの耐久性低下が防止できる。
【０２２３】
（ヘ）．グロー異常判定実行条件算出処理（図８，９）では、グロー通電に関して異常可能性が無いことが明確となっても（Ｓ４２２で「ＮＯ」）、前回以前のトリップにて既に本異常判定が「ＯＮ」とされていれば（Ｓ４２４で「ＹＥＳ」）、グロー異常判定実行を許可している（Ｓ４２６）。
【０２２４】
このことにより修理後に、仮異常判定処理（図１０）を実行でき、場合により更に本異常判定処理（図１１）を実行でき、ダイアグノーシスなどの内部情報を修理後の正常なグロー通電に対応したものとすることができる。
【０２２５】
［実施の形態２］
本実施の形態では、始動時から行われる通常のグロー通電制御によるグロー通電オン時は、始動時前提条件算出処理（図５）のみを実行して、始動時前提条件「ＯＮ」又は「ＯＦＦ」を設定する。そしてこのグロー通電オンの完了後に、始動時前提条件「ＯＮ」の場合に限って、あるいは以前に既に本異常判定が「ＯＮ」であった場合に限って、異常有無判定のために一時的にグロー通電オン・オフを強制的に実行するものである。
【０２２６】
本実施の形態では、前記実施の形態１の図９に示したグロー異常判定実行条件算出処理の一部の処理の代わりに、図１９に示す処理が実行される。又、仮異常判定処理（図１０）及び本異常判定処理（図１１）の代わりに、図２０に示す仮異常判定処理及び図２１に示す本異常判定処理が実行される。又、図１３に示したグロー異常判定停止条件算出処理の一部の処理の代わりに、図２２に示す処理が実行される。これ以外の構成及び処理は前記実施の形態１と同じである。
【０２２７】
図１９では、グロー異常判定実行許可のための条件として、図９のステップＳ４１６，Ｓ４１８の代わりに通常のグロー通電時間終了後、待機時間が経過したか否かが判定される（Ｓ４１７）。
【０２２８】
したがって、通常のグロー通電時間が終了しなければ、グロー異常判定実行許可（Ｓ４２６）はなされないので、通常のグロー通電オン時においては、強制的グロー通電「ＯＦＦ」も強制的グロー通電「ＯＮ」も実行されない。
【０２２９】
そして通常のグロー通電時間が終了した後、グロー異常判定実行条件算出処理（図８，１９）のステップＳ４００〜Ｓ４２０にて「ＹＥＳ」と判定される状態となると、次に始動時前提条件が「ＯＮ」か否かが判定される（Ｓ４２２）。ここで始動時前提条件算出処理（図５）にて設定された始動時前提条件が「ＯＦＦ」であれば（Ｓ４２２で「ＮＯ」）、次に本異常判定が既に「ＯＮ」とされているか否かが判定される（Ｓ４２４）。本異常判定が「ＯＦＦ」であれば（Ｓ４２４で「ＮＯ」）、このまま一旦本処理を終了する。したがって同一トリップ内では、強制的グロー通電「ＯＮ」「ＯＦＦ」は実行されることはない。この場合は、前記実施の形態１の図１４に示したタイミングチャートと同じように推移することになる。
【０２３０】
始動時前提条件算出処理（図５）にて始動時前提条件が「ＯＮ」と決定される場合について説明する。この場合は、やはり通常のグロー通電時間内においては、強制的グロー通電「ＯＦＦ」も強制的グロー通電「ＯＮ」も実行されない。例えば、図２３のタイミングチャートに示すごとく、イグニッションスイッチをオンし（ｔ５０）、スタータ許可によりスタータ３０が駆動を開始し（ｔ５１）、エンジン始動が完了する（ｔ５２）ものとする。この時、実際の始動時間Ｔｓｔａは標準始動時間Ｔｓｔａｎｏｒｍより大きく、バッテリ電圧ＶＢは始動時標準最低電圧Ｖｓｔａｎｏｒｍよりも低下した履歴がない。このため始動時前提条件算出処理（図５）のステップＳ３１０にて「ＹＥＳ」、ステップＳ３１４にて「ＮＯ」と判定されて、前提条件としては「ＯＮ」が設定される（Ｓ３１８）。しかし直ちに仮異常判定処理（図２０）を開始することはなく、通常のグロー通電時間の完了を待つ。
【０２３１】
そして通常のグロー通電時間が完了した後（ｔ５３〜）、グロー異常判定実行条件算出処理（図８，１９）のステップＳ４００〜Ｓ４２０にて「ＹＥＳ」と判定されるようになると、次に始動時前提条件が「ＯＮ」か否かが判定される（Ｓ４２２）。ここでは始動時前提条件が「ＯＮ」であるので（Ｓ４２２で「ＹＥＳ」）、正常判定は「ＯＦＦ」とされてから（Ｓ４２３）、グロー異常判定実行は許可される（Ｓ４２６：ｔ５４）。このことにより仮異常判定処理（図２０）が開始されて、ステップＳ８００で「ＹＥＳ」、ステップＳ８０２で「ＹＥＳ」と判定され、ステップＳ８０４〜Ｓ８０８の処理後に、強制的グロー通電オンが実行される（Ｓ８１０）。尚、ステップＳ８００〜Ｓ８０８は、前記実施の形態１の仮異常判定処理（図１０）のステップＳ５００〜５０８の処理と実質的に同じ処理である。
【０２３２】
そして、次式１２を満足した状態がエンジン負荷の上昇を判定するに必要な時間継続したか否かが判定される（Ｓ８１２）。
【０２３３】
【数１２】
ＱＦＩＮＣ − Ｑｏｌｄ３ ≧ ｄＱ３ … ［式１２］
ここで上昇判定値ｄＱ３は、電気エネルギー消費増加に対応した燃料噴射量上昇分の最低限の値を予め実験等により求めて設定したものである。
【０２３４】
前記式１２を満足していない場合や、前記式１２を満足してもエンジン負荷上昇判定に必要な時間継続していない場合には（Ｓ８１２で「ＮＯ」）、次式１３を満足した状態がバッテリ電圧ＶＢの降下を判定するに必要な時間継続したか否かが判定される（Ｓ８１４）。
【０２３５】
【数１３】
ＶＢｏｌｄ３ − ＶＢ ≧ ｄＶ３ … ［式１３］
ここで降下判定値ｄＶ３は、グロー通電オンに対応したバッテリ電圧ＶＢ降下の最低限の値を予め実験等により求めて設定したものである。
【０２３６】
前記式１３を満足していない場合や、前記式１３を満足しても電圧降下判定に必要な時間継続していない場合には（Ｓ８１４で「ＮＯ」）、次式１４を満足した状態がエンジン負荷の無変化状態を判定するに必要な時間継続したか否かが判定される（Ｓ８１６）。
【０２３７】
【数１４】
ＱＦＩＮＣ − Ｑｏｌｄ３ ＜ ｄＱ３ … ［式１４］
この式１４は前記式１２が満足されていない状態を表している。
【０２３８】
前記式１４を満足していない場合や、前記式１４を満足してもエンジン負荷の無変化判定に必要な時間継続していない場合には（Ｓ８１６で「ＮＯ」）、このまま一旦本処理を終了する。
【０２３９】
図２３のタイミングチャートに示したごとく、ステップＳ８１２もステップＳ８１４も共に満足されない内に、前記式１４を満足した状態がエンジン負荷の無変化状態を判定するに必要な時間継続した場合（Ｓ８１６で「ＹＥＳ」：ｔ５５）、仮異常判定が「ＯＮ」に設定される（Ｓ８２０）。すなわち強制的なグロー通電オン（Ｓ８１０）の前にて、オフであるはずのグロー通電がオン状態のままであったり、あるいはＥＣＵ５２の指令（Ｓ８１０）通りにグロー通電がオンとならなかったことを示している。したがって仮異常判定「ＯＮ」との情報がＥＣＵ５２内のバックアップＲＡＭに記憶される。こうして一旦本処理を終了する。
【０２４０】
このように仮異常判定「ＯＮ」とされたことにより、グロー異常判定停止条件算出処理（図１２，２２）により、仮異常判定処理（図２０）は停止され（Ｓ７２６）、本異常判定処理（図２１）の実質的な処理が実行されるようになる（Ｓ９００で「ＹＥＳ」）。
【０２４１】
そして本異常判定処理（図２１）にてステップＳ９００〜Ｓ９０６の処理の後に強制的にグロー通電がオフにされる（Ｓ９０８）。尚、ステップＳ９００〜Ｓ９０６は、グロー通電オンとオフとの違いはあるが、前記実施の形態１の仮異常判定処理（図１１）のステップＳ６００〜６０６の処理と実質的に同じ処理である。
【０２４２】
次に上述したディーゼルエンジン２に対する負荷が正常に低下したことを判定するために、アイドル回転数制御下での最終基本噴射量指令値ＱＦＩＮＣの変化と、バッテリ電圧ＶＢの変化を判定する。
【０２４３】
まず次式１５を満足した状態がエンジン負荷の低下を判定するに必要な時間継続したか否かが判定される（Ｓ９１０）。
【０２４４】
【数１５】
Ｑｏｌｄ４ − ＱＦＩＮＣ ≧ ｄＱ４ … ［式１５］
ここで低下判定値ｄＱ４は、電気エネルギー消費低減に対応した燃料噴射量低下分の最低限の値を予め実験等により求めて設定したものである。
【０２４５】
前記式１５を満足していない場合や、前記式１５を満足しても負荷低下判定に必要な時間継続していない場合には（Ｓ９１０で「ＮＯ」）、次式１６を満足した状態がバッテリ電圧ＶＢの上昇を判定するに必要な時間継続したか否かが判定される（Ｓ９１２）。
【０２４６】
【数１６】
ＶＢ − ＶＢｏｌｄ４ ≧ ｄＶ４ … ［式１６］
ここで上昇判定値ｄＶ４は、グロー通電オフに対応したバッテリ電圧ＶＢの上昇の最低限の値を予め実験等により求めて設定したものである。
【０２４７】
前記式１６を満足していない場合や、前記式１６を満足しても電圧上昇判定に必要な時間継続していない場合には（Ｓ９１２で「ＮＯ」）、次式１７を満足した状態がエンジン負荷の無変化状態を判定するに必要な時間継続したか否かが判定される（Ｓ９１４）。
【０２４８】
【数１７】
Ｑｏｌｄ４ − ＱＦＩＮＣ ＜ ｄＱ４ … ［式１７］
この式１７は前記式１５が満足されていない状態を表している。
【０２４９】
前記式１７を満足していない場合や、前記式１７を満足してもエンジン負荷の無変化判定に必要な時間継続していない場合には（Ｓ９１４で「ＮＯ」）、このまま一旦本処理を終了する。
【０２５０】
図２３のタイミングチャートのごとく、ステップＳ９１０もステップＳ９１２も共に満足されない内に、前記式１７を満足した状態がエンジン負荷の無変化状態を判定するに必要な時間継続した場合（Ｓ９１４で「ＹＥＳ」：ｔ５６）、本異常判定は「ＯＮ」に設定される（Ｓ９１８）。すなわち強制的なグロー通電オフ（Ｓ９０８）の前にて、正常にグロー通電オンが実行されていないか、あるいは、ＥＣＵ５２の指令（Ｓ９０８）通りにグロー通電がオフとならなかったことを示している。
【０２５１】
そして前記仮異常判定処理（図２０）における異常であるとの判定（仮異常判定）とともに、本異常判定処理（図２１）にても異常であるとの判定がなされたことになり、グロー通電が異常であることに高い確実性が存在するので、本異常判定「ＯＮ」との情報がＥＣＵ５２内のバックアップＲＡＭに記憶される。こうして一旦本処理を終了する。
【０２５２】
このように本異常判定「ＯＮ」とされたことにより、グロー異常判定停止条件算出処理（図１２，２２）のステップＳ７１４で「ＮＯ」と判定されて、グロー異常判定実行が不許可となり（Ｓ７２４）、本異常判定処理（図２１）が停止される。上述した処理により始動時前提条件＝「ＯＮ」、本異常判定＝「ＯＮ」、正常判定＝「ＯＦＦ」がダイアグノーシスなどの内部情報としてＥＣＵ５２のメモリに記録されることになる。
【０２５３】
次に図２４のタイミングチャートにて、正常判定が「ＯＮ」に設定される場合について説明する。時刻ｔ６０〜ｔ６４までは前記図２３の場合の時刻ｔ５０〜ｔ５４と同様に推移する。そして時刻ｔ６４から開始された仮異常判定処理（図２０）にて、強制的グロー通電オンが実行される（Ｓ８１０）。この強制的グロー通電「ＯＮ」により実際にグロープラグ２２に電流が正常に流れ始めたことにより、燃料噴射量は上昇を開始し、バッテリ電圧ＶＢは下降を開始する。そして時刻ｔ６５にて前記式１３の関係が最初に成立して必要な時間継続することにより（Ｓ８１４で「ＹＥＳ」）、正常判定は「ＯＮ」となる（Ｓ８１８）。このように正常判定「ＯＮ」とされたことにより、グロー異常判定停止条件算出処理（図１２，２２）のステップＳ７１４で「ＮＯ」と判定されて、仮異常判定は「ＯＦＦ」（Ｓ７２０）となり、グロー異常判定実行は不許可になる（Ｓ７２４）。このため仮異常判定処理（図２０）と本異常判定処理（図２１）とが停止される。又、待機時間経過後にグロー通電はオフに戻される（Ｓ７２３：ｔ６６）。
【０２５４】
上述した処理により始動時前提条件＝「ＯＮ」、本異常判定＝「ＯＦＦ」、正常判定＝「ＯＮ」がＥＣＵ５２のメモリに記録されることになる。
次に図２５のタイミングチャートにて、本異常判定処理（図２１）にて初めてグロー通電変化が正常に行われた場合について説明する。時刻ｔ７０〜ｔ７４までは前記図２３の場合の時刻ｔ５０〜ｔ５４と同様に推移する。そして時刻ｔ７４から開始された仮異常判定処理（図２０）にて、強制的グロー通電オンが実行される（Ｓ８１０）。この強制的グロー通電オンによってはグロープラグ２２には電流が流れないので、前記式１２，１３は満足されることなく、前記式１４が満足される状態が継続することになる（Ｓ８１６で「ＹＥＳ」：ｔ７５）。このため仮異常判定は「ＯＮ」に設定される（Ｓ８２０）。仮異常判定が「ＯＮ」となったことにより仮異常判定処理（図２０）は停止され（Ｓ７２６）、本異常判定処理（図２１）では、仮異常判定処理（図２０）のステップＳ８１０によるグロー通電オンから待機時間後に強制的グロー通電オフが実行される（Ｓ９０８：ｔ７６）。
【０２５５】
この強制的グロー通電オフにより、今までグロープラグ２２に流れていた電流が正常に停止すると、燃料噴射量は下降を開始し、バッテリ電圧ＶＢは上昇を開始する。そして時刻ｔ７７にて前記式１６の関係が最初に成立して継続することにより（Ｓ９１２で「ＹＥＳ」）、仮異常判定は「ＯＦＦ」に戻される（Ｓ９１６）。このように仮異常判定は「ＯＦＦ」となったことにより、本異常判定処理（図２１）は実質的に処理を停止する（Ｓ９００で「ＮＯ」）。上述した処理により始動時前提条件＝「ＯＮ」、本異常判定＝「ＯＦＦ」、正常判定＝「ＯＦＦ」がＥＣＵ５２のメモリに記録されることになる。尚、適当なタイミング、例えばアクセルペダル２４を踏み込んだりした場合（Ｓ７０６で「ＮＯ」）にグロー異常判定実行は不許可となる（Ｓ７２４）。
【０２５６】
図２６に、前回以前のトリップにてグロー通電の異常が判明し、修理が完了された直後のエンジン始動の例を表す。時刻ｔ８０〜ｔ８３までは前記図１４にて説明した時刻ｔ０〜ｔ３までと同様に推移する。この間に、始動時前提条件算出処理（図５）では正常にグロー通電がなされたのでステップＳ３１０で「ＮＯ」又はステップＳ３１４で「ＹＥＳ」と判定されて、始動時前提条件は「ＯＦＦ」に設定される（Ｓ３１６：ｔ８２）。
【０２５７】
そして通常のグロー通電処理が完了した後（ｔ８３〜）に、グロー異常判定実行条件算出処理（図８，１９）のステップＳ４００〜Ｓ４２０の条件が成立すると、次に始動時前提条件が「ＯＮ」か否かが判定される（Ｓ４２２）。ここでは始動時前提条件が「ＯＦＦ」であるので（Ｓ４２２で「ＮＯ」）、次に前回以前のトリップにて既に異常判定が「ＯＮ」に設定されているか否かが判定される（Ｓ４２４）。ここでは既に異常判定は「ＯＮ」であるので（Ｓ４２４で「ＹＥＳ」）、本異常判定を「ＯＦＦ」に戻して（Ｓ４２５）、グロー異常判定実行が許可される（Ｓ４２６：ｔ８４）。このことにより仮異常判定処理（図２０）が実行されて、時刻ｔ８５にて前記式１３が成立した状態が継続したことにより（Ｓ８１４で「ＹＥＳ」）、正常判定は「ＯＮ」に設定される（Ｓ８１８）。
【０２５８】
このことにより図２２のステップＳ７１４にて「ＮＯ」と判定されるようになり、ステップＳ７２３の処理により待機時間後に強制的にグロー通電は「ＯＦＦ」にされる（ｔ８６）。又、仮異常判定「ＯＦＦ」（Ｓ７２０）とグロー異常判定実行の不許可（Ｓ７２４）により、仮異常判定処理（図２０）も本異常判定処理（図２１）も共に実質的な処理を停止する。上述した処理により始動時前提条件＝「ＯＦＦ」、本異常判定＝「ＯＦＦ」、正常判定＝「ＯＮ」がＥＣＵ５２のメモリに記録されることになる。
【０２５９】
上述した構成において、グロー異常判定実行条件算出処理（図８，１９）、仮異常判定処理（図２０）、本異常判定処理（図２１）及びグロー異常判定停止条件算出処理（図１２，２２）が異常有無判定手段としての処理に相当する。又、グロー異常判定実行条件算出処理（図８，１９）及び仮異常判定処理（図２０）が第１異常判定手段としての処理に、本異常判定処理（図２１）及びグロー異常判定停止条件算出処理（図１２，２２）が第２異常判定手段としての処理に相当する。異常可能性判定手段及び始動完了前状態検出手段については前記実施の形態１の場合と同じである。
【０２６０】
以上説明した本実施の形態２によれば、以下の効果が得られる。
（イ）．前記実施の形態１の（イ）、（ロ）、（ニ）〜（ヘ）と同じ効果を生じる。
【０２６１】
（ロ）．仮異常判定処理（図２０）及び本異常判定処理（図２１）は通常のグロー通電時間が完了した後に実行されるので、通常のグロー通電制御に全く影響しない。このため、特に冷間時などにおいて始動後のエンジン運転が一層安定化できる。
【０２６２】
又、このグロー通電異常検出は、通常のグロー通電時間内で実行するものではないので、ディーゼルエンジンが既に暖機されていて通常のグロー通電時間が短い場合でも、グロー通電の異常検出の機会を十分に得られる。
【０２６３】
［その他の実施の形態］
（ａ）．前記始動時前提条件算出処理（図５）におけるバッテリ電圧ＶＢの履歴は、始動時（始動開始から始動完了まで）の履歴であったが、例えばイグニッションスイッチ・オンから始動開始までの期間の履歴も含めても良いし、ディーゼルエンジン２の始動完了直後のバッテリ電圧ＶＢの履歴を含めても良い。又、イグニッションスイッチ・オンから始動開始までの期間のバッテリ電圧ＶＢの履歴に限っても良く、ディーゼルエンジン２の始動完了後でのバッテリ電圧ＶＢの履歴に限っても良い。
【０２６４】
（ｂ）．前記始動時前提条件算出処理（図５）においては始動時前提条件を判定するのに、始動時間Ｔｓｔａとバッテリ電圧ＶＢの履歴とを用いた。これ以外に、始動時間Ｔｓｔａのみによって始動時前提条件の「ＯＮ」・「ＯＦＦ」を判定しても良く、又、バッテリ電圧ＶＢの履歴のみによって始動時前提条件の「ＯＮ」・「ＯＦＦ」を判定しても良い。
【０２６５】
又、始動時間Ｔｓｔａが標準始動時間Ｔｓｔａｎｏｒｍ以下の条件と、バッテリ電圧ＶＢが始動時標準最低電圧Ｖｓｔａｎｏｒｍより低下した履歴の条件とのいずれかが満足された場合に、始動時前提条件は「ＯＦＦ」にされていた。これ以外に、前記２つの条件が共に満足された場合に始動時前提条件を「ＯＦＦ」に設定し、共に満足されない場合は「ＯＮ」に設定するようにしても良い。
【０２６６】
（ｃ）．前記グロー異常判定実行条件算出処理（図８，９，１９）では、ディーゼルエンジン２のアイドル時に、グロー異常判定実行を許可して（Ｓ４２６）、仮異常判定処理（図１０，２０）及び本異常判定処理（図１１，２１）が実行されるようにしていた。これ以外に、アイドル時でなくても、アイドル時に準じる状態であれば仮異常判定処理（図１０，２０）及び本異常判定処理（図１１，２１）の実行を許可するようにしても良い。例えば、下り坂走行や慣性走行時においてクラッチが切られたりしてディーゼルエンジンから車輪への動力伝達がなされていない場合に、安定回転を条件に仮異常判定処理（図１０，２０）及び本異常判定処理（図１１，２１）が実行されるようにしても良い。
【０２６７】
（ｄ）．仮異常判定処理（図１０，２０）及び本異常判定処理（図１１，２１）では、燃料噴射量とバッテリ電圧とのいずれかにグロー通電切り替えに伴う十分な変化が生じた場合に、正常判定「ＯＮ」あるいは仮異常判定「ＯＦＦ」の設定を行っていた。これ以外に、燃料噴射量のみの変化を判定しても良く、バッテリ電圧のみの変化を判定しても良い。
【０２６８】
又、上記判定処理では、燃料噴射量が十分変化しないことを判定して、仮異常判定「ＯＮ」あるいは本異常判定「ＯＮ」に設定していたが、これ以外に、バッテリ電圧が十分変化しないことを判定しても良い。又は、燃料噴射量もバッテリ電圧も共に十分変化しないことを判定しても良い。
【０２６９】
燃料噴射量やバッテリ電圧とともに、あるいはこれらの代わりに、オルタネータ５４に対する制御デューティＤＦの変化を、ディーゼルエンジン２の運転状態変化として捉えても良い。すなわち強制的なグロー通電切り替えに伴い制御デューティＤＦの十分な変化が生じた場合に正常判定「ＯＮ」あるいは仮異常判定「ＯＦＦ」の設定を行い、十分な変化が生じない場合に仮異常判定「ＯＮ」あるいは本異常判定「ＯＮ」に設定しても良い。
【０２７０】
又、仮異常判定や本異常判定にて判定対象とする燃料噴射量としては、最終基本噴射量指令値ＱＦＩＮＣを用いていたが、この代わりに、基本噴射量指令値ＱＢＡＳＥ、ガバナ噴射量指令値ＱＧＯＶあるいはアイドル噴射量補正値ＱＩＩを用いても良い。
【０２７１】
又、燃料噴射量、バッテリ電圧、前記制御デューティに限らず、エンジン負荷などのディーゼルエンジンの運転状態変化の指標となるものであれば、仮異常判定や本異常判定での判定対象とすることができる。
【０２７２】
（ｅ）．本異常判定を「ＯＮ」とするのは、仮異常判定処理（図１０，２０）及び本異常判定処理（図１１，２１）において、共にグロー通電切り替えに伴う燃料噴射量変化やバッテリ電圧変化が十分に生じなかった場合であった。これ以外に仮異常判定処理（図１０，２０）の処理のみを実行して、燃料噴射量とバッテリ電圧とのいずれかにグロー通電切り替えに伴う十分な変化が生じた場合に正常判定「ＯＮ」とし、燃料噴射量が十分変化しない場合に本異常判定「ＯＮ」としても良い。
【０２７３】
（ｆ）．前記実施の形態１では、異常検出のための強制的グロー通電の切り替えは、通常のグロー通電オン期間内での実行に限られていた。これ以外に、前記実施の形態１と前記実施の形態２とを組み合わせた構成としても良い。
【０２７４】
例えば、異常検出のための強制的グロー通電切り替えが通常のグロー通電オン期間内でできなかった場合には、通常のグロー通電オン期間が経過した後に、アイドル運転状態となった時に、前記実施の形態２と同じく強制的なグロー通電オンとオフとを実行することにより、異常判定を実行しても良い。このようにすることにより、実施の形態１，２に比較して、極力早期にかつ、確実に強制的グロー通電による異常判定が実行できることになる。
【０２７５】
（ｇ）．前記各実施の形態では、温度要因として冷却水温を用いていたが、この代わりにエンジンオイルの温度を用いても良し、ディーゼルエンジンにおける燃焼による発熱と放熱との収支によりエンジン温度を推定して用いても良い。
【図面の簡単な説明】
【図１】実施の形態１の蓄圧式ディーゼルエンジンとその制御系統を示す概略構成図。
【図２】実施の形態１のグロープラグへの電力供給系統図。
【図３】実施の形態１の燃料噴射量制御処理のフローチャート。
【図４】同じく燃料噴射量制御処理のフローチャート。
【図５】同じく始動時前提条件算出処理のフローチャート。
【図６】上記始動時前提条件算出処理にて始動開始時冷却水温度ＴＨＷｓから標準始動時間Ｔｓｔａｎｏｒｍを求めるためのマップの構成説明図。
【図７】上記始動時前提条件算出処理にて始動開始時冷却水温度ＴＨＷｓから始動時標準最低電圧Ｖｓｔａｎｏｒｍを求めるためのマップの構成説明図。
【図８】実施の形態１のグロー異常判定実行条件算出処理のフローチャート。
【図９】同じくグロー異常判定実行条件算出処理のフローチャート。
【図１０】同じく仮異常判定処理のフローチャート。
【図１１】同じく本異常判定処理のフローチャート。
【図１２】同じくグロー異常判定停止条件算出処理のフローチャート。
【図１３】同じくグロー異常判定停止条件算出処理のフローチャート。
【図１４】実施の形態１の制御の一例を示すタイミングチャート。
【図１５】同じく制御の一例を示すタイミングチャート。
【図１６】同じく制御の一例を示すタイミングチャート。
【図１７】同じく制御の一例を示すタイミングチャート。
【図１８】同じく制御の一例を示すタイミングチャート。
【図１９】実施の形態２のグロー異常判定実行条件算出処理における一部のフローチャート。
【図２０】同じく仮異常判定処理のフローチャート。
【図２１】同じく本異常判定処理のフローチャート。
【図２２】同じくグロー異常判定停止条件算出処理における一部のフローチャート。
【図２３】実施の形態２の制御の一例を示すタイミングチャート。
【図２４】同じく制御の一例を示すタイミングチャート。
【図２５】同じく制御の一例を示すタイミングチャート。
【図２６】同じく制御の一例を示すタイミングチャート。
【符号の説明】
２…蓄圧式ディーゼルエンジン（コモンレール型ディーゼルエンジン）、２ａ…クランクシャフト、２ｂ…ベルト、４…インジェクタ、４ａ…電磁弁、６…コモンレール、８…供給配管、８ａ…逆止弁、１０…サプライポンプ、１０ａ…吐出ポート、１０ｂ…吸入ポート、１０ｃ…圧力制御弁、１０ｄ…リターンポート、１２…燃料タンク、１４…フィルタ、１６…リターン配管、１８…吸気通路、１８ａ…吸気弁、２０…排気通路、２０ａ…排気弁、２２…グロープラグ、２２ａ…グローリレー、２４…アクセルペダル、２６…アクセルセンサ、３０…スタータ、３０ａ…スタータスイッチ、３２…水温センサ、３４…油温センサ、３６…燃温センサ、３８…燃圧センサ、４０…ＮＥセンサ、４２…気筒判別センサ、４４…トランスミッション、４６…シフトポジションセンサ、４８…車速センサ、５０…エアコンスイッチ、５２…ＥＣＵ、５４…オルタネータ、５４ａ…電圧レギュレータ、５６…エアコン用コンプレッサ、５８…オルタネータ用コントローラ、６０…バッテリ。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method and an apparatus for detecting an abnormality of a glow plug provided in a diesel engine.
[0002]
[Prior art]
Conventionally, in order to improve startability, when starting a diesel engine, the diesel engine is preheated by energizing the glow plug in advance. Such a glow plug is provided with an energization heating element. However, when the energization heating element itself is disconnected or the power supply line to the energization heating element is disconnected, it is started particularly in the cold state. Cause problems with sex. For this reason, devices for detecting an abnormality of a glow plug have been proposed by providing a glow plug disconnection detection device (Japanese Patent Laid-Open Nos. 11-182400, 57-26275, 58-13581). Issue gazette).
[0003]
[Problems to be solved by the invention]
In the above prior art, the presence / absence of abnormality such as disconnection of the glow plug is determined from the voltage change accompanying the energization to the glow plug performed at the time of starting. However, if the abnormality determination is performed using the normal energization control of the glow plug as described above, there may be a case where the abnormality determination has to be performed in a situation where highly sensitive detection cannot be performed. Judgment may not be possible.
[0004]
For this reason, the energization on / off is forcibly executed separately from the normal glow plug energization control, increasing the degree of freedom when performing glow plug anomaly detection, and providing high sensitivity under conditions appropriate for anomaly detection. It is conceivable to detect abnormality and determine abnormality.
[0005]
However, if the glow plug energization on / off is executed separately from the normal energization control as described above, the glow plug abnormality determination can be made accurately, but the on / off of the circuit opening / closing mechanism such as the glow relay is switched. There is a possibility that the number of times increases and the durability of the circuit opening / closing mechanism is lowered.
[0006]
SUMMARY OF THE INVENTION An object of the present invention is to provide a glow plug abnormality detection method and apparatus that can maintain accurate determination of a glow plug abnormality and also suppress a decrease in durability of a circuit opening / closing mechanism.
[0007]
[Means for Solving the Problems]
In the following, means for achieving the above object and its effects are described.
The abnormality detection method for a glow plug according to claim 1, wherein the glow plug is energized. Based on the phenomenon caused by forcibly changing A method of detecting an abnormality of a glow plug provided in a diesel engine by executing a glow plug abnormality determination, wherein the glow plug is energized prior to the abnormality determination. Based on the phenomenon that occurred without forcibly changing An abnormality possibility determination of a glow plug is executed, and when it is determined that there is no possibility of abnormality in the abnormality possibility determination, the abnormality presence / absence determination is not executed.
[0008]
Glow plug energization state Based on phenomena that occur without forcibly changing The possibility of abnormality of the glow plug is less reliable as abnormality detection than when forced change is performed. However, it can be determined with high certainty whether there is a possibility of abnormality. This possibility of abnormality is determined by the glow plug energization status. Based on the phenomenon caused by forcibly changing If it is determined that there is no possibility of abnormality by executing before determining whether there is an abnormality in the glow plug, it is not necessary to determine whether there is an abnormality.
[0009]
Therefore, when it is determined that there is a possibility of abnormality in the abnormality possibility determination, that is, it is determined that there is no possibility of abnormality, it is only necessary to execute the abnormality presence / absence determination with high certainty of abnormality detection. As a result, the number of forced changes in the energization state of the glow plug can be suppressed. In this way, accurate glow plug abnormality determination can be maintained, and deterioration of the durability of the circuit opening / closing mechanism can be suppressed.
[0010]
It should be noted here that "forced change" (Forcibly changing) "Means a process of changing the energization state of the glow plug in order to detect abnormality of the glow plug. The same applies to other claims.
In the glow plug abnormality detection method according to claim 2, in the configuration according to claim 1, the forced change of the energized state is switching between energization on and off of the glow plug. To do.
[0011]
The forced change in the energized state includes, for example, a forced change caused by switching between energization on and off of the glow plug. In such a forced change, a phenomenon related to an abnormality of the glow plug occurs. Although it tends to appear, the durability of the circuit opening / closing mechanism is also likely to deteriorate. From this, it is possible to reduce the number of changes in the energized state by assuming that the possibility of abnormality is determined in the possibility of abnormality determination, so that accurate abnormality determination is maintained. In addition, the deterioration of the durability of the circuit opening / closing mechanism can be suppressed.
[0012]
The abnormality detection method for a glow plug according to claim 3, wherein the abnormality possibility determination is performed based on an engine state before completion of starting of the diesel engine in a state where the glow plug is energized. It is characterized by determining the possibility of plug abnormality.
[0013]
If energization of the glow plug is turned on and the glow plug is normally generating heat, the electric energy for heat generation is consumed, and the diesel engine can be started smoothly. However, if the glow plug is not energized and the glow plug is not actually energized or if the energization amount is abnormally low, no electrical energy is consumed for the glow plug to generate heat, and the engine It cannot start smoothly. In this way, the abnormality of the glow plug is reflected in the engine state before the start is completed. For this reason, the possibility of abnormality can be determined based on the engine state before completion of starting the diesel engine.
[0014]
According to a fourth aspect of the present invention, there is provided the glow plug abnormality detection method according to the third aspect, wherein the engine state before the completion of starting the diesel engine is a length of start time.
[0015]
If energization to the glow plug is normally performed and the engine starts smoothly, the start is completed at an early stage. Therefore, the start time, that is, the time from the start to the start is shortened. However, if the engine is not started smoothly because the energization of the glow plug is not normal, the start time becomes longer. Therefore, if the start time is short, it can be determined that there is no possibility of abnormality of the glow plug. Conversely, if the start time is long, there may be other causes, but the possibility that the glow plug is abnormal cannot be denied.
[0016]
In this way, it is possible to determine whether or not there is a possibility of abnormality by the length of the starting time without forcibly changing the energization state of the glow plug.
6. The glow plug abnormality detection method according to claim 5, wherein in the abnormality possibility determination, if the start time is shorter than a determination reference time, it is determined that there is no possibility of abnormality, and the start time is determined. If it is longer than the reference time, it is determined that there is a possibility of abnormality.
[0017]
Thus, the determination reference time is provided and compared with the actual start time. When the starting time is shorter than the determination reference time, it can be seen that the glow plug is normally generating heat. However, if the starting time is longer than the determination reference time, there may be other causes, but it is understood that there is a possibility that the heat generation is defective due to an abnormality of the glow plug. Thus, by comparing the start time and the determination reference time, it is possible to easily determine whether there is a possibility of abnormality without forcibly changing the energization state of the glow plug.
[0018]
The abnormality detection method for a glow plug according to claim 6 is characterized in that, in claim 3, the engine state before completion of starting of the diesel engine is a high battery voltage.
[0019]
If the glow plug is normally energized at the start-up or before the start and generates heat, the battery voltage drops with the energization before the start-up is completed. On the other hand, when the glow plug is not energized or the energization amount is abnormally low, there is almost no drop in battery voltage. Therefore, if the battery voltage has dropped before completion of the start, it can be determined that there is no possibility of abnormality of the glow plug. On the other hand, if the battery voltage has not dropped before the start is completed, there may be other causes, but the possibility that the glow plug is abnormal cannot be denied.
[0020]
In this way, it is possible to determine whether there is a possibility of abnormality based on the battery voltage level without forcibly changing the energization state of the glow plug.
The abnormality detection method for a glow plug according to claim 7, wherein in the abnormality determination in claim 6, an abnormality is possible when the battery voltage has dropped below a determination reference voltage before completion of starting of the diesel engine. It is characterized in that it is determined that there is no possibility, and when there is no decrease, it is determined that there is a possibility of abnormality.
[0021]
Thus, the determination reference voltage is provided and compared with the battery voltage before the actual start is completed. If the battery voltage has fallen below the determination reference voltage before the start is completed, it is understood that the glow plug is normally generating heat due to energization. However, if the battery voltage has not dropped below the judgment reference voltage before the completion of the start-up, there may be other causes, but there may be a failure in heat generation due to abnormal energization of the glow plug. I understand. In this way, by comparing the battery voltage with the determination reference voltage, it is possible to easily determine whether there is a possibility of abnormality without forcibly changing the energization state of the glow plug.
[0022]
The abnormality detection method for a glow plug according to claim 8 is characterized in that, in claim 3, the engine state before completion of starting of the diesel engine is a length of start time and a high battery voltage.
[0023]
Thus, by determining both the length of the start time and the height of the battery voltage, it is possible to more reliably determine whether there is a possibility of abnormality without forcibly changing the energization state of the glow plug.
[0024]
The abnormality detection method for a glow plug according to claim 9, wherein in the abnormality possibility determination, the start time is shorter than a determination reference time, or the battery voltage is lower than a determination reference voltage. In the case, it is determined that there is no possibility of abnormality, and it is determined that there is a possibility of abnormality when the starting time is longer than the determination reference time and the battery voltage has never dropped below the determination reference voltage. .
[0025]
Furthermore, it is possible to easily determine whether there is a possibility of abnormality by providing a determination reference time and comparing it with the actual start time, and by providing a determination reference voltage and comparing it with the actual battery voltage before completion of the start.
[0026]
The abnormality detection method for a glow plug according to claim 10 is characterized in that, in claim 5 or 9, the determination reference time is set according to a cooling water temperature.
Since the start time is also affected by the temperature, by setting the determination reference time according to the cooling water temperature, an appropriate determination reference time can be obtained, and the presence or absence of the possibility of abnormality can be determined more accurately.
[0027]
The abnormality detection method for a glow plug according to claim 11 is characterized in that, in claim 7 or 9, the determination reference voltage is set according to a cooling water temperature.
Since the battery voltage is also affected by the temperature, by setting the determination reference voltage according to the cooling water temperature, an appropriate determination reference voltage can be obtained and the presence or absence of the possibility of abnormality can be determined more accurately.
[0028]
The abnormality detection method for a glow plug according to claim 12 is started for starting a diesel engine when it is determined in any one of claims 1 to 11 that there is a possibility of abnormality in the abnormality possibility determination. When the abnormality presence / absence determination cannot be completed within the set time for energization of the glow plug, the abnormality presence / absence determination is not executed.
[0029]
By doing so, the abnormality presence / absence determination can be completed within the set time for turning on the energization of the glow plug started for starting. For this reason, the normal energization is not prolonged due to the forced change of the energization state by the abnormality presence / absence determination. Therefore, it is possible to suppress energy consumption due to the glow plug abnormality determination process.
[0030]
In the glow plug abnormality detection method according to claim 13, in any one of claims 1 to 12, when it is determined that there is a possibility of abnormality in the abnormality possibility determination, The abnormality presence / absence determination is not executed.
[0031]
By limiting the abnormality presence / absence determination during idling, it is difficult to be influenced by other factors, and it is possible to determine the presence / absence of abnormality more accurately.
The abnormality detection method for a glow plug according to claim 14, wherein, in any one of claims 1 to 13, when it is determined that there is a possibility of abnormality in the abnormality possibility determination, the battery voltage is outside the determination reference voltage range. Then, the abnormality presence / absence determination is not executed.
[0032]
If the battery voltage is too low, the load on the power generation mechanism such as an alternator may have reached 100%, and even if the energized state is forcibly changed in this state, the load on the diesel engine may hardly change. Therefore, it is not possible to determine whether there is an abnormality with high accuracy. Furthermore, if the battery voltage is too high, the load on the power generation mechanism is 0%, and even if the energized state is forcibly changed in this state, there may be little change in the load on the diesel engine. Cannot determine whether there is an abnormality. Therefore, the determination reference voltage range is provided, and the abnormality presence / absence determination is not performed when the battery voltage is outside this range, thereby preventing a decrease in the accuracy of the abnormality presence / absence determination.
[0033]
The abnormality detection method for a glow plug according to claim 15, wherein the abnormality determination in any one of claims 1 to 14 is based on a change in an operating state of a diesel engine accompanying a forced change in an energization state of the glow plug. It is characterized by determining whether there is an abnormality in the plug.
[0034]
More specifically, the determination of the presence / absence of abnormality can be performed with a high degree of certainty by measuring the state of change in the operating state of the diesel engine caused by the forced change in the energization state of the glow plug. Moreover, since the presence / absence determination of abnormality is based on the assumption that the possibility of abnormality is determined in the possibility of abnormality determination, the forced change of the energized state is prevented even if there is no possibility of abnormality. it can. Here, the forced change of the energized state may be once or may be repeated twice or more, but is preferably once or twice in terms of durability of a circuit opening / closing mechanism such as a glow relay.
[0035]
17. The glow plug abnormality detection method according to claim 16, wherein in the abnormality determination, the first forced change in the energized state of the glow plug is performed and the operation of the diesel engine associated with the first forced change is determined. The first determination is executed based on the state change, and when it is determined that the first determination is normal, the abnormality presence / absence determination is terminated and the energization state is returned to the state before the first forced change. When it is not possible to determine that the current state is normal, a second forced change is made to return the energized state to the state before the first forced change, and the second based on the change in the operating state of the diesel engine accompanying the second forced change. The determination is executed, and when it is determined that there is an abnormality in the second determination, the determination of the presence / absence of the abnormality is terminated. End the abnormality presence / absence judgment And wherein the Rukoto.
[0036]
Thus, in the abnormality presence / absence determination, it is confirmed that the abnormality is in two stages of the first forced change and the second forced change, and a reliable abnormality determination can be performed. In addition, the first forced change is canceled out by the second forced change, so that the abnormality can be reliably determined, and when the abnormality presence / absence determination is completed, the original glow plug energized state can be restored.
[0037]
The glow plug abnormality detection method according to claim 17, wherein the first forced change is a process of changing to energization off if the energization is already in the abnormality determination in claim 16, and the second forced change. Is a process that turns on energization.
[0038]
More specifically, when the energization is already in an energized state where energization of the glow plug is performed by the normal glow energization control, the first forced change is energized off, and the second forced change is It may be turned on. As a result, it is possible to reliably determine the abnormality and to return to the original glow plug energization ON state when the abnormality presence / absence determination is completed, so that stable operation of the diesel engine is not hindered.
[0039]
The abnormality detection method for a glow plug according to claim 18, wherein the first forced change is a process for changing to energization on if the energization is already off in the determination of the presence / absence of an abnormality in claim 16. Is a process that changes to energization off.
[0040]
Conversely, if the energization of the glow plug has already been completed and the energization is already off, the first forced change may be energized on and the second forcible change may be energized off. When the abnormality presence / absence determination is completed, the original glow plug energization off state can be restored.
[0041]
20. The glow plug abnormality detection method according to claim 19, wherein when the first forcible change is executed, the second forcible change is performed if a preset time interval has not elapsed. Is not executed.
[0042]
If energization off and energization on are executed at short time intervals, the durability of a circuit opening / closing mechanism such as a glow relay may be reduced. Therefore, by ensuring a time interval from the first forced change to the second forced change, the durability of the circuit opening / closing mechanism is prevented from being lowered.
[0043]
In a glow plug abnormality detection method according to a twentieth aspect, in any one of the fifteenth to nineteenth aspects, the operating state change of the diesel engine is a change in an engine load.
[0044]
When energization of the glow plug starts or the energization amount increases due to the first forced change or the second forced change, the power generation amount increases in response to an increase in the battery consumption rate, and the load on the diesel engine increases. Rise. On the contrary, when the energization to the glow plug is stopped or the energization amount is decreased due to the first forcible change or the second forcible change, the power generation amount is reduced corresponding to the decrease in the battery consumption rate, and the diesel engine The load becomes low. For this reason, when the energization to the glow plug is not normally performed, the engine load change corresponding to the first forced change or the second forced change does not occur. This makes it possible to determine whether or not the glow plug is abnormal based on the engine load change.
[0045]
The abnormality detection method for a glow plug according to claim 21 is characterized in that, in claim 20, a change in engine load is captured by a change in fuel injection amount during idle speed control.
[0046]
In the idling engine speed control, if the load on the diesel engine increases, the fuel injection amount is increased to maintain the diesel engine rotation speed. Conversely, if the load decreases, the fuel injection quantity is decreased to reduce the diesel engine Maintain the rotation speed. Therefore, when the energization to the glow plug is not normally performed, the fuel injection amount change corresponding to the first forced change or the second forced change does not occur. By measuring the change in the fuel injection amount in this way, it is possible to determine whether or not the glow plug is abnormal.
[0047]
The abnormality detection method for a glow plug according to claim 22 is characterized in that, in any of claims 15 to 19, the change in the operating state of the diesel engine is a change in battery voltage.
[0048]
When energization to the glow plug is started or the energization amount is increased by the first forced change by the first abnormality determination unit or the second forced change by the second abnormality determination unit, the voltage drop of the battery used for energization Occurs. Conversely, when the energization to the glow plug is stopped or the energization amount is decreased due to the first forced change or the second forced change, the battery voltage rises. For this reason, when the energization to the glow plug is not normally performed, the battery voltage does not change corresponding to the first forced change or the second forced change. Therefore, it is possible to determine whether or not the glow plug is abnormal by measuring the change in the battery voltage.
[0049]
The abnormality detection method for a glow plug according to claim 23 is characterized in that, in any of claims 15 to 19, the change in the operating state of the diesel engine is a change in the fuel injection amount and a change in the battery voltage.
[0050]
As described above, since the first forced change or the second forced change appears in both the fuel injection amount and the battery voltage, it is possible to more accurately determine whether or not the glow plug is abnormal by measuring both the changes. it can.
[0051]
An abnormality detection device for a glow plug according to claim 24 is a device for detecting an abnormality of a glow plug provided in a diesel engine, based on a phenomenon that occurs without forcibly changing the energization state of the glow plug. An abnormality possibility determination unit that performs plug abnormality possibility determination, and when the abnormality possibility determination unit determines that there is a possibility of abnormality in the glow plug, the energization state of the glow plug is forcibly changed. Based on the phenomenon that occurred in response to the forced change, it is determined whether or not there is an abnormality in the glow plug, and when the abnormality possibility determination means determines that there is no abnormality in the glow plug, An abnormality presence / absence determination unit that does not execute the abnormality presence / absence determination accompanied by a forced change in the energization state of the glow plug is provided.
[0052]
The abnormality possibility determination performed by the abnormality possibility determination means is less reliable as abnormality detection than when the glow plug is forcedly changed. However, since the possibility of a glow plug abnormality can be determined with a high degree of certainty, if the abnormality possibility determination means determines that there is no possibility of a glow plug abnormality, the abnormality presence / absence determination means executes an abnormality presence / absence determination. There is no need to do.
[0053]
For this reason, when the abnormality possibility determination means determines that there is a possibility of abnormality, that is, it is determined that there is no possibility of abnormality, the abnormality presence / absence determination means has a high certainty of abnormality detection. Therefore, the number of forced changes in the energization state of the glow plug can be suppressed. In this way, accurate glow plug abnormality determination can be maintained and deterioration of the durability of the circuit opening / closing mechanism can be suppressed.
[0054]
In the glow plug abnormality detection device according to claim 25, in the configuration according to claim 24, the forced change of the energized state is switching between energization on and off of the glow plug. And
[0055]
The forced change of the energized state is a forced change especially between energization on and off of the glow plug, and in such a forced change, a phenomenon related to an abnormality of the glow plug is likely to appear. Also, the durability of the circuit opening / closing mechanism is likely to deteriorate. From this, the abnormality presence / absence determination means can reduce the number of changes in the energized state on the assumption that the abnormality possibility determination means has determined that there is an abnormality possibility, and the accuracy of abnormality determination can be reduced. It can be maintained, and a decrease in durability of the circuit opening / closing mechanism can be suppressed.
[0056]
The abnormality detection device for a glow plug according to claim 26, wherein the abnormality possibility determination means includes a pre-start completion state detection means for detecting an engine state before completion of diesel engine start. It is characterized in that the possibility of abnormality of the glow plug is determined based on the engine state before completion of starting the diesel engine detected by the state detection means before starting completion while the plug is energized.
[0057]
If energization of the glow plug is turned on and the glow plug is normally generating heat, the electric energy for heat generation is consumed, and the diesel engine can be started smoothly. However, if the glow plug is not energized and the glow plug is not actually energized or if the energization amount is abnormally low, no electrical energy is consumed for the glow plug to generate heat, and the engine It cannot start smoothly. In this way, the abnormality of the glow plug is reflected in the engine state before the start is completed. For this reason, the abnormality possibility determination means can determine whether or not there is an abnormality possibility based on the engine state before completion of starting of the diesel engine detected by the state detection means before starting completion.
[0058]
The abnormality detection device for a glow plug according to claim 27, wherein the state detection means before start completion detects a length of start time as an engine state before completion of start of the diesel engine. .
[0059]
If energization to the glow plug is normally performed and the engine starts smoothly, the start is completed at an early stage. Therefore, the start time, that is, the time from the start to the start is shortened. However, if the engine is not started smoothly because the energization of the glow plug is not normal, the start time becomes longer. Therefore, the abnormality possibility determination means detects the start time by the state detection means before start completion, and can determine that there is no possibility of abnormality of the glow plug if this start time is short. Conversely, if the start time is long, there may be other causes, but the possibility that the glow plug is abnormal cannot be denied.
[0060]
In this way, the abnormality possibility determination means can determine the presence or absence of abnormality possibility according to the length of the start time without forcibly changing the energization state of the glow plug.
In the glow plug abnormality detection device according to claim 28, in claim 27, the abnormality possibility determination means determines whether the abnormality is detected when the start time detected by the pre-start completion state detection means is shorter than a determination reference time. It is judged that there is no possibility of abnormality of the plug, and when it is long, it is judged that there is a possibility of abnormality of the glow plug.
[0061]
As described above, the abnormality possibility determination means provides the determination reference time and compares it with the actual start time detected by the pre-start completion state detection means. When the start time is shorter than the determination reference time, it is understood that the glow plug is normally generating heat and there is no possibility of abnormality. On the other hand, when the starting time is longer than the determination reference time, it is understood that there is a possibility that the heat generation is defective due to an abnormality of the glow plug. Thus, the abnormality possibility determination means can easily determine the presence or absence of abnormality possibility without making a forced change in the energization state of the glow plug by comparing the start time and the determination reference time.
[0062]
The abnormality detection device for a glow plug according to claim 29, wherein the state detection means before starting completion detects the level of the battery voltage as the engine state before completion of starting the diesel engine. .
[0063]
If the glow plug is normally energized at the start-up or before the start and generates heat, the battery voltage drops with the energization before the start-up is completed. On the other hand, when the glow plug is not energized or the energization amount is abnormally low, there is almost no drop in battery voltage. Therefore, the abnormality possibility determination means can determine that there is no possibility of abnormality of the glow plug if the battery voltage has dropped before completion of the start. On the other hand, if the battery voltage has not dropped before the start is completed, there may be other causes, but the possibility that the glow plug is abnormal cannot be denied.
[0064]
In this way, the abnormality possibility determination means can determine the presence or absence of abnormality possibility based on the battery voltage level without forcibly changing the energization state of the glow plug.
30. The glow plug abnormality detection device according to claim 30, wherein the abnormality possibility determination means determines whether or not the battery voltage detected by the pre-start completion state detection means before completion of start of the diesel engine is determined. If the voltage has dropped below the reference voltage, it is determined that there is no possibility of abnormality, and if it has not dropped, it is determined that there is a possibility of abnormality.
[0065]
In this way, the abnormality possibility determination means provides the determination reference voltage and compares it with the actual battery voltage detected before completion of the start by the pre-start completion state detection means. If the battery voltage has fallen below the determination reference voltage, it is understood that the glow plug is sufficiently energized and normally generates heat, and there is no possibility of abnormality. On the other hand, if it has never been lowered, it can be seen that there is a possibility of heat generation failure because the glow plug is not sufficiently energized. In this way, the abnormality possibility determination means can easily determine the presence or absence of an abnormality possibility without making a forced change in the energization state of the glow plug, by comparing the battery voltage before the start is completed with the determination reference voltage.
[0066]
The abnormality detection device for a glow plug according to claim 31, wherein the state detection means before start completion is configured to determine a length of start time and a battery voltage as the engine state before completion of starting the diesel engine. It is characterized by detecting.
[0067]
By determining both the length of the start time detected in this way and the level of the battery voltage before the start is completed by the abnormality possibility determination means, there is no need to forcibly change the energization state of the glow plug. Therefore, it is possible to more reliably determine whether there is an abnormality.
[0068]
The abnormality detection device for a glow plug according to claim 32, wherein the abnormality possibility determination means according to claim 31, wherein the start-up time is shorter than a determination reference time or the battery voltage has decreased below a determination reference voltage. If there is, it is determined that there is no possibility of abnormality, and it is determined that there is a possibility of abnormality when the start time is longer than the determination reference time and the battery voltage has never dropped below the determination reference voltage. To do.
[0069]
In this way, the possibility of abnormality determination means compares the determination reference time with the actual start time, and easily determines the presence or absence of the possibility of abnormality by comparing the determination reference voltage with the actual battery voltage before completion of the start. it can.
[0070]
The abnormality detection device for a glow plug according to a thirty-third aspect is characterized in that in the thirty-eighth or thirty-second aspect, the abnormality possibility determination means sets the determination reference time according to a cooling water temperature.
[0071]
Since the start time is also affected by the temperature, the abnormality possibility determination means sets the determination reference time according to the cooling water temperature, so that an appropriate determination reference time can be obtained and the presence or absence of abnormality is more accurately determined. Can be judged.
[0072]
A glow plug abnormality detection device according to a thirty-fourth aspect is the one according to the thirty-third or thirty-second aspect, wherein the abnormality possibility determination means sets the determination reference voltage according to a cooling water temperature.
[0073]
Since the battery voltage is also affected by the temperature, the abnormality possibility determination means sets the determination reference voltage according to the cooling water temperature, so that an appropriate determination reference voltage can be obtained and the presence or absence of abnormality is more accurately determined. Can be judged.
[0074]
In the glow plug abnormality detection device according to claim 35, in any one of claims 24 to 34, when the abnormality presence / absence determination means determines that there is a possibility of abnormality by the abnormality possibility determination means, When the abnormality presence / absence determination cannot be completed within a set time for energization of the glow plug started for starting, the abnormality presence / absence determination is not executed.
[0075]
By doing so, the abnormality presence / absence determining means can complete the abnormality presence / absence determination within the set time of energization on the glow plug started for starting. For this reason, the normal energization is not prolonged due to the forced change of the energization state by the abnormality presence / absence determining means. Therefore, energy consumption due to abnormality determination can be suppressed.
[0076]
In the glow plug abnormality detection device according to claim 36, in any one of claims 24 to 35, when the abnormality presence / absence determination means determines that there is a possibility of abnormality by the abnormality possibility determination means, The abnormality determination is not executed except during idle speed control.
[0077]
The abnormality presence / absence determination means is less susceptible to the influence of other factors by limiting the execution of the abnormality presence / absence determination during idling, thereby enabling more accurate determination of abnormality presence / absence.
In the glow plug abnormality detection device according to claim 37, in any one of claims 24 to 36, when the abnormality presence determination means determines that there is a possibility of abnormality by the abnormality possibility determination means, The abnormality determination is not performed when the battery voltage is outside the determination reference voltage range.
[0078]
If the battery voltage is too low, the load on the power generation mechanism such as an alternator may have reached 100%, and even if the abnormality determination means forcibly changes the energized state in this state, the load change of the diesel engine is almost Since it may not occur, the presence or absence of abnormality cannot be determined with high accuracy. Furthermore, if the battery voltage is too high, the load on the power generation mechanism is 0%, and even if the abnormality presence / absence determining means forcibly changes the energized state in this state, the load change of the diesel engine may hardly occur. Therefore, the presence / absence of abnormality cannot be determined with high accuracy. Therefore, the abnormality presence / absence determining means provides a determination reference voltage range, and does not execute the abnormality presence / absence determination when the battery voltage is outside this range, thereby preventing a decrease in the accuracy of the abnormality presence / absence determination.
[0079]
In the glow plug abnormality detection device according to claim 38, in any one of claims 24 to 37, the abnormality presence / absence determining means is based on a change in operating state of the diesel engine accompanying a forced change in the energization state of the glow plug. It is characterized by determining whether or not the glow plug is abnormal.
[0080]
With this configuration, the abnormality presence / absence determining means can determine the presence / absence of abnormality with high certainty. Moreover, since the determination that there is a possibility of abnormality by the abnormality possibility determination means is a premise for executing the abnormality presence / absence determination, the number of executions of forced change of the energized state by the abnormality presence / absence determination means can be suppressed. When the forced change of the energized state by the abnormality presence / absence determining means is executed, the forced change of the energized state may be performed once or repeated twice or more, but the durability of the circuit opening / closing mechanism such as a glow relay may be repeated. In terms of nature, once or twice is preferable.
[0081]
40. The glow plug abnormality detection device according to claim 39, wherein the abnormality presence / absence determining means determines whether or not the abnormality is detected in the glow plug by the abnormality possibility determining means. The first abnormality determination means for performing a first forced change in the energized state of the engine and executing a determination based on a change in the operating state of the diesel engine associated with the first forced change, and the first abnormality determination means is normal. When it is determined that there is an abnormality, the abnormality presence / absence determination is terminated and the energized state is returned to before the first forcible change, and when the first abnormality determining means cannot determine that the current is normal, the energized state is changed to the first The second forced change to be returned before the forced change is performed, the determination is performed based on the change in the operating state of the diesel engine accompanying the second forced change, and the abnormality is determined to be abnormal in the determination Presence Exit constant, characterized in that a second abnormality determining means for terminating said abnormality existence determination without determining the determination if it is unable determined as abnormal by said determination.
[0082]
As described above, the abnormality presence / absence determining means confirms the abnormality in two stages of the first forced change and the second forced change, and can perform reliable abnormality determination. In addition, the first forced change is offset by the second forced change, so that it is possible to reliably determine the abnormality and return to the original glow plug energized state when the abnormality presence / absence determination is completed.
[0083]
The abnormality detection device for a glow plug according to claim 40, wherein the first forced change by the first abnormality determination means is the current abnormality on-state at the start of processing of the abnormality presence determination means according to claim 39. Is a process for changing energization off, and the second forced change by the second abnormality determination means is a process for changing energization on.
[0084]
More specifically, when the glow plug is energized by normal control and is already energized, the first forced change by the first abnormality determination means is the energization off and the second abnormality. The second forcible change by the determination means may be energized on. As a result, the abnormality presence / absence determining means can reliably determine the abnormality, and when the abnormality presence / absence determination is completed, the original glow plug energized state can be restored, so that stable operation of the diesel engine is not hindered.
[0085]
The abnormality detection device for a glow plug according to claim 41, wherein the first forced change by the first abnormality determination unit is the current detection state in claim 39 if the energization is already off at the start of the processing of the abnormality presence / absence determination unit. Is a process of turning on energization, and the second forced change by the second abnormality determining means is a process of turning off energization.
[0086]
Conversely, if energization of the glow plug has been completed and the energization has already been turned off, the first forced change by the first abnormality determining means is energized on, and the second forced change by the second abnormality determining means is energized off. It is also good. As a result, the abnormality presence / absence determining means can reliably determine the abnormality and can return to the original glow plug energized state when the abnormality presence / absence determination is completed.
[0087]
The abnormality detection device for a glow plug according to claim 42, wherein when the first abnormality determination means executes the first forced change in claim 40 or 41, the second abnormality determination means is preset. The second forcible change is not executed unless the set time interval has elapsed.
[0088]
If energization off and energization on are executed at short time intervals, the durability of a circuit opening / closing mechanism such as a glow relay may be reduced. For this reason, the second abnormality determining means executes the second forced change after securing the time interval after the first forced change. This can prevent a decrease in durability of the circuit opening / closing mechanism.
[0089]
In the glow plug abnormality detection device according to claim 43, in any one of claims 38 to 42, the change in operating state of the diesel engine is a change in engine load.
[0090]
When the energization of the glow plug starts or the energization amount increases due to the first forced change by the first abnormality determination means or the second forced change by the second abnormality determination means, it corresponds to an increase in the battery consumption rate. As a result, the amount of power generation increases and the load on the diesel engine increases. On the contrary, when the energization to the glow plug is stopped or the energization amount is decreased due to the first forcible change or the second forcible change, the power generation amount is reduced corresponding to the decrease in the battery consumption rate, and the diesel engine The load becomes low. For this reason, when the energization to the glow plug is not normally performed, the engine load change corresponding to the first forced change or the second forced change does not occur. Therefore, the abnormality presence / absence determining means can determine the presence / absence of abnormality of the glow plug based on the change in the engine load as the change in the operating state of the diesel engine.
[0091]
According to a 44th aspect of the present invention, there is provided the glow plug abnormality detecting device according to the 43rd aspect, wherein the abnormality presence / absence determining means captures a change in engine load due to a change in fuel injection amount during idle speed control.
[0092]
In idle speed control, if the load on the diesel engine increases, the fuel injection amount is increased to maintain the rotation speed of the diesel engine. Conversely, if the load decreases, the fuel injection amount is decreased to decrease the diesel engine Maintain the rotation speed. Therefore, when the energization to the glow plug is not normally performed, the fuel injection amount change corresponding to the first forced change or the second forced change does not occur. Thus, the abnormality presence / absence determining means can determine whether or not there is an abnormality in the glow plug by measuring a change in the fuel injection amount.
[0093]
According to a 45th aspect of the present invention, in the glow plug abnormality detection device, the change in the operating state of the diesel engine is a change in the battery voltage.
[0094]
When energization of the glow plug is started or the energization amount is increased by the first forced change or the second forced change, a voltage drop of the battery for energization occurs. Conversely, when the energization to the glow plug is stopped or the energization amount is decreased due to the first forced change or the second forced change, the battery voltage rises. Therefore, when the energization to the glow plug is not normally performed, the battery voltage does not change corresponding to the first forced change or the second forced change. For this reason, the abnormality presence / absence determining means can determine the presence / absence of abnormality of the glow plug by measuring a change in the battery voltage as a change in the operating state of the diesel engine.
[0095]
According to a 46th aspect of the present invention, there is provided the glow plug abnormality detecting device according to any one of the 38th to 42nd aspects, wherein the change in the operating state of the diesel engine is a change in the fuel injection amount and a change in the battery voltage.
[0096]
As described above, since the first forced change or the second forced change appears in both the fuel injection amount and the battery voltage, the abnormality presence / absence determining means more accurately determines whether or not the glow plug is abnormal based on both the changes. Can be determined.
[0097]
DETAILED DESCRIPTION OF THE INVENTION
[Embodiment 1]
FIG. 1 is a schematic configuration diagram showing a pressure accumulation type diesel engine (common rail type diesel engine) 2 and its control system as the first embodiment. The accumulator diesel engine 2 is mounted on a vehicle as an automobile engine.
[0098]
The diesel engine 2 is provided with a plurality of cylinders (four cylinders in the present embodiment, but only one cylinder is illustrated) # 1, # 2, # 3, and # 4, and each cylinder # 1. The injectors 4 are provided for the combustion chambers # 4 to # 4, respectively. Fuel injection from the injector 4 to each cylinder # 1 to # 4 of the diesel engine 2 is controlled by turning on and off the electromagnetic valve 4a for injection control.
[0099]
The injector 4 is connected to a common rail 6 as an accumulator pipe common to each cylinder. While the electromagnetic valve 4a for injection control is open, fuel in the common rail 6 is sent from the injector 4 to each cylinder # 1 to # 4. Is injected into the inside. A relatively high pressure corresponding to the fuel injection pressure is accumulated in the common rail 6. In order to realize this pressure accumulation, the common rail 6 is connected to the discharge port 10 a of the supply pump 10 via the supply pipe 8. A check valve 8 a is provided in the middle of the supply pipe 8. Due to the presence of the check valve 8a, the supply of fuel from the supply pump 10 to the common rail 6 is allowed, and the reverse flow of fuel from the common rail 6 to the supply pump 10 is prevented.
[0100]
The supply pump 10 is connected to the fuel tank 12 through a suction port 10b, and a filter 14 is provided in the middle thereof. The supply pump 10 sucks fuel from the fuel tank 12 through the filter 14. At the same time, the supply pump 10 reciprocates the plunger by a cam (not shown) synchronized with the rotation of the diesel engine 2 to increase the fuel pressure to a predetermined required pressure and supply high pressure fuel to the common rail 6. ing.
[0101]
Further, a pressure control valve 10 c is provided in the vicinity of the discharge port 10 a of the supply pump 10. This pressure control valve 10c is for controlling the fuel pressure discharged toward the common rail 6 from the discharge port 10a. By opening the pressure control valve 10c, surplus fuel not discharged from the discharge port 10a is returned from the return port 10d provided in the supply pump 10 to the fuel tank 12 via the return pipe 16. Yes.
[0102]
An intake passage 18 and an exhaust passage 20 are connected to the combustion chambers of the cylinders # 1 to # 4 of the diesel engine 2, respectively. A throttle valve (not shown) is provided in the intake passage 18, and the flow rate of intake air introduced into the combustion chamber is adjusted by adjusting the opening of the throttle valve according to the operating state of the diesel engine 2.
[0103]
A glow plug 22 is disposed in the combustion chamber of each cylinder # 1 to # 4 of the diesel engine 2. The glow plug 22 becomes red hot when a current is passed through the glow relay 22a immediately before starting the diesel engine 2, and a part of the fuel spray is blown onto the glow plug 22 to promote ignition and combustion. Device. The glow plug 22 is subjected to an abnormality determination such as disconnection by processing as described later.
[0104]
The diesel engine 2 is provided with the following various sensors, which detect the operating state of the diesel engine 2 in the first embodiment. That is, as shown in FIG. 1, an accelerator sensor 26 for detecting the accelerator opening degree ACCPF is provided in the vicinity of the accelerator pedal 24. The diesel engine 2 is provided with a starter 30 for starting the diesel engine 2. The starter 30 is provided with a starter switch 30a that detects its operating state. The cylinder block of the diesel engine 2 is provided with a water temperature sensor 32 for detecting the temperature of the cooling water (cooling water temperature THW). Further, an oil temperature sensor 34 for detecting the temperature THO of the engine oil is provided in the oil pan (not shown). The return pipe 16 is provided with a fuel temperature sensor 36 for detecting the fuel temperature THF. The common rail 6 is provided with a fuel pressure sensor 38 for detecting the pressure of fuel in the common rail 6. An NE sensor 40 is provided in the vicinity of a pulsar (not shown) provided on a crankshaft (not shown) of the diesel engine 2. Further, the rotation of the crankshaft is transmitted via a timing belt or the like to a camshaft (not shown) for opening and closing the intake valve 18a and the exhaust valve 20a. The camshaft is set to rotate at a rotational speed that is 1/2 of the crankshaft. A cylinder discrimination sensor 42 is provided in the vicinity of a pulsar (not shown) provided on the camshaft. In the first embodiment, the engine speed NE, the crank angle CA, and the intake top dead center (TDC) of the first cylinder # 1 are calculated based on the pulse signals output from both the sensors 40 and 42. The transmission 44 is provided with a shift position sensor 46 to detect the shift state of the transmission 44. A vehicle speed sensor 48 is provided on the output shaft side of the transmission 44 to detect the vehicle speed SPD from the rotational speed of the output shaft. An air conditioner (not shown) that is driven by the output of the diesel engine 2 is provided, and an air conditioner switch 50 is provided for instructing driving of the air conditioner.
[0105]
In the first embodiment, an electronic control unit (ECU) 52 for controlling various controls of the diesel engine 2 is provided. The ECU 52 uses the diesel engine 2 for fuel injection amount control and glow energization control, which will be described later. A process for controlling the above, a process for determining a glow energization abnormality, which will be described later, and the like are performed. The ECU 52 is a central processing control device (CPU), a read only memory (ROM) that stores various programs and maps in advance, a random access memory (RAM) that temporarily stores CPU calculation results, and calculation results and pre-stored The microcomputer mainly includes a backup RAM for storing data, a timer counter, an input interface, an output interface, and the like. The accelerator sensor 26, the water temperature sensor 32, the oil temperature sensor 34, the fuel temperature sensor 36, the fuel pressure sensor 38, and the like described above are input to the ECU 52 via a buffer, a multiplexer, and an A / D converter (all not shown), respectively. It is connected to the. The NE sensor 40, the cylinder discrimination sensor 42, the vehicle speed sensor 48, and the like are connected to the input interface of the ECU 52 via a waveform shaping circuit (not shown). Further, the starter switch 30a, the shift position sensor 46, the air conditioner switch 50, and the like are directly connected to the input interface of the ECU 52. In addition to this, the battery voltage VB, the control duty DF of the alternator, and the like are input to the ECU 52 and the values are read. The CPU reads signals from the sensors and switches via the input interface. The solenoid valve 4a, the pressure control valve 10c, the glow relay 22a, etc. are connected to the output interface of the ECU 52 via drive circuits, respectively. The CPU performs control calculation based on the input value read via the input interface, and suitably controls the electromagnetic valve 4a, the pressure control valve 10c, the glow relay 22a, and the like via the output interface.
[0106]
Here, as shown in the power supply system diagram of FIG. 2, the alternator 54 and the air conditioner compressor 56 are rotationally driven from the crankshaft 2a of the diesel engine 2 via the belt 2b. Inside the alternator 54, a voltage regulator 54a is provided. The voltage regulator 54 a is configured to output a voltage corresponding to the duty signal from the alternator controller 58 from the alternator 54. The controller 58 detects the voltage VB of the battery 60 and performs duty control on the voltage regulator 54a so as to maintain the charged state of the battery 60 in an appropriate state. The glow plug 22 can generate heat by being supplied with electric power from the battery 60 and the alternator 54 when the glow relay 22 a is turned on by the ECU 52.
[0107]
Next, in the present embodiment, fuel injection amount control processing and glow energization control processing among the control executed by the ECU 52 will be described.
3 and 4 show the fuel injection amount control process. This process is executed by interruption every constant crank angle (every explosion stroke). The steps in the flowchart corresponding to individual processes are represented by “S˜”.
[0108]
When the fuel injection amount control process is started, first, based on the engine speed NE detected by the signal of the NE sensor 40, the accelerator opening degree ACCPF detected by the signal of the accelerator sensor 26, and the signal of the shift position sensor 46. Data necessary for control of the detected shift position SFT and the vehicle speed SPD detected by the signal of the vehicle speed sensor 48 is read into the work area in the RAM of the ECU 52 (S110).
[0109]
Next, based on the engine speed NE and the accelerator opening ACCPF, an idle governor injection quantity command value QGOV1 is calculated from an idle governor injection quantity command value map using the engine speed NE and the accelerator opening ACCPF as parameters ( S120). This map is experimentally determined in advance for idling and is stored in the ROM of the ECU 52. In this map, since numerical values are discretely arranged, if there is no matching value as a parameter, it is obtained by interpolation calculation. Such map setting and calculation by interpolation are the same for other maps.
[0110]
Next, the non-idle governor injection amount command value QGOV2 is calculated from the non-idle governor injection amount command value map using the engine speed NE and the accelerator opening degree ACCPF as parameters. (S130). Further, the auxiliary governor injection amount command value QGOV3 that gives an auxiliary characteristic to the non-idle governor injection amount command value QGOV2 is set based on the engine speed NE and the accelerator opening ACCPF, and the engine speed NE and the accelerator opening ACCPF are parameters. Is calculated from the auxiliary governor injection amount command value map (S140).
[0111]
Next, it is determined whether it is other than idle (S150). For example, when the vehicle speed SPD is 0 km / h and the accelerator sensor 26 indicates the accelerator opening ACCPF = 0% after the warm-up is completed, it is determined that the vehicle is in the idle state. If the engine is in the idle state (“NO” in S150), as shown in the following equation 1, a rotational speed deviation NEDL between the target rotational speed NTRG at the idle time and the actual rotational speed NE is calculated (S160).
[0112]
[Expression 1]
NEDL ← NTRG-NE ... [Formula 1]
Next, an injection amount correction value QIIDL corresponding to the rotational speed deviation NEDL is obtained from a map using the rotational speed deviation NEDL as a parameter (S170). Instead of this map, the injection amount correction value QIIDL may be obtained from a function having the rotation speed deviation NEDL as a parameter.
[0113]
Then, as shown in the following equation 2, the idle injection amount correction value QII is calculated based on the injection amount correction value QIIDL (S180).
[0114]
[Expression 2]
QII ← QII ± QIIDL ... [Formula 2]
Here, QII on the right side is the idle injection amount correction value QII obtained during the previous control cycle. “± QIIDL” means “+ QIIDL” when NTRG ≧ NE, and means “−QIIDL” when NTRG <NE.
[0115]
After step S180, the governor injection amount command value QGOV is calculated by the following equation 3 (S190). If it is determined in step S150 that the vehicle is not idle ("YES" in S150), the process directly proceeds to the calculation process of the governor injection amount command value QGOV (S190).
[0116]
[Equation 3]

Here, QIP is an offset value when a load such as an air conditioner is generated when idling, and QIPB is an offset value when a load such as an air conditioner is generated when not idling. MAX () is an operator that extracts the maximum value among the values in parentheses.
[0117]
Next, it is determined whether acceleration / deceleration is in progress (S200). This determination is made, for example, based on whether the governor injection amount command value QGOV is larger or smaller than the basic injection amount command value QBASEOL calculated during the previous control cycle.
[0118]
If it is at the time of acceleration / deceleration (“YES” in S200), an increase / decrease suppression process of the governor injection amount command value QGOV is then performed. This is performed to prevent a shock that occurs when the governor injection amount command value QGOV changes rapidly. Therefore, when the governor injection amount command value QGOV that is greatly changed compared to the basic injection amount command value QBASEOL is calculated in step S190, the value of the governor injection amount command value QGOV is corrected so as not to cause a shock. .
[0119]
Next, the governor injection amount command value QGOV is set as the basic injection amount command value QBASE (S220). If it is determined in step S200 that acceleration / deceleration is not being performed ("NO" in S200), the process directly proceeds to step S220.
[0120]
Then, the basic injection amount command value QBASE is guard-processed with the maximum injection amount command value QFULL as shown in the following equation 4 to calculate the final basic injection amount command value QFINC (S230).
[0121]
[Expression 4]
QFINC ← MIN (QBASE, QFULL) ... [Formula 4]
Here, MIN () is an operator that extracts the minimum value among the values in parentheses.
[0122]
Next, as shown in the following equation 5, the pilot injection amount command value QPL is subtracted from the final basic injection amount command value QFINC to calculate the main injection amount command value QFPL (S240).
[0123]
[Equation 5]
QFPL ← QFINC-QPL ... [Formula 5]
Next, based on the value of the main injection amount command value QFPL, the main injection period TQFPL is calculated by the map or the function fq (S250). Further, based on the pilot injection amount command value QPL, a pilot injection period TQPL is calculated by a map or a function fp (S260). Then, the basic injection amount command value QBASE calculated this time is set as the previous basic injection amount command value QBASEOL (S270). Thus, the fuel injection amount control process is temporarily terminated.
[0124]
In the glow energization control process, energization to the glow plug 22 is turned on when the ignition switch is detected to be turned on, and the glow plug 22 is supplied with power from the battery 60, thereby starting the heat generation of the glow plug 22. The start of the diesel engine 2 starts when the starter 30 is turned on. After that, when the start is completed, the ECU 52 is controlled to turn off the energization of the glow plug 22 after the delay time has elapsed. Here, the delay time is controlled to be shorter if the coolant temperature THW is higher.
[0125]
Next, processing for detecting an abnormality such as disconnection of the glow plug 22 will be described. The process corresponding to FIG.5 and FIGS.8-13 is shown.
First, the starting precondition calculation process (FIG. 5) will be described. This process is repeatedly executed in a time cycle when the ECU 52 is turned on. When this process is started, it is first determined whether or not a starting precondition described later is in an undecided state (S300). Since the initial setting state when the power is turned on is an undetermined state (“YES” in S300), it is determined whether or not the cooling water temperature THW detected by the water temperature sensor 32 is equal to or lower than a preset water temperature determination value. It is determined (S301). When the cooling water temperature THW> the water temperature determination value, there is no significant difference in engine startability between when the glow plug 22 is normally generating heat and when the glow plug 22 is not generating heat due to disconnection or the like. For this reason, since the determination process of the starting preconditions performed in steps S304 to S314 cannot be performed with high accuracy, “NO” is determined in step S301. As a result, “ON” is set as the starting precondition (S318). In this way, this process is once completed. As a result, the starting precondition is determined, and in the next control cycle, it is determined as “NO” in step S300, and the substantial process of the starting precondition calculation process (FIG. 5) ends. Further, since the starting precondition is determined to be “ON”, a glow abnormality determination for forcibly turning on / off energization (hereinafter referred to as “glow energization”) to the glow plug 22 described later is executed.
[0126]
On the other hand, when the cooling water temperature THW ≦ the water temperature determination value (“YES” in S301), it is next determined whether or not the start is completed (S302). If the start has not been completed (“NO” in S302), the present process is temporarily terminated as it is. Until the start is completed, only the process determined as “NO” in step S302 is repeated. During this period, the engine start is started by cranking, and the engine start is completed when the engine speed NE reaches a speed at which start completion is determined by combustion of the fuel injected from the injector 4.
[0127]
When the engine start is completed (“YES” in S302), the start time Tsta is read next (S304). The start time Tsta is a value obtained by counting the time from the start to the start completion by a process separately executed by the ECU 52.
[0128]
Next, the starting coolant temperature THWs is read (S306). The start-up cooling water temperature THWs is the coolant temperature THW detected at the start-up and held in the memory by a process separately performed by the ECU 52.
[0129]
Next, a standard start time Tstanorm (corresponding to a determination reference time) is calculated (S308). The standard start time Tstantorm is a start time indicating an upper limit value of a start time expected when the glow plug 22 is normally generating heat, or a range further allowed from this upper limit value. Since this standard start time Tstannor changes according to the start-up cooling water temperature THWs, for example, a map showing the configuration shown in FIG. 6 is stored in the ROM of the ECU 52, and in step S308, the start-up start cooling water temperature THWs. Based on the above, the standard start time Tsternor is calculated.
[0130]
Next, it is determined whether or not the actual start time Tsta is longer than the standard start time Tstannorm (S310). Here, if Tsta ≦ Tstannorm (“NO” in S310), it indicates that the glow plug 22 has generated heat normally and has been smoothly started. In order not to execute the abnormality determination process to be performed, “OFF” is set as the precondition at the start (S316), and this process is temporarily ended. As a result, the starting precondition is determined, and in step S300, “NO” is determined in the next control cycle, and the substantial process of the starting precondition calculation process (FIG. 5) is completed. Thus, the state where “OFF” is set as the precondition at the start indicates that there is no possibility of abnormal glow energization.
[0131]
On the other hand, if Tsta> Tstannorm (“YES” in S310), the history of the battery voltage VB at the start is read (S312). The battery voltage VB at the time of starting, that is, from the start to the completion of the start, is detected by a process separately executed by the ECU 52. In the same process, for example, the battery voltage VB is lower than the starting standard minimum voltage Vstannorm (corresponding to the determination reference voltage) calculated based on the starting coolant temperature THWs according to the map shown in FIG. Whether or not the state exists is stored in the memory as a history. This starting standard minimum voltage Vstannorm is a voltage value indicating a degree of a battery voltage drop expected when the glow plug 22 is normally supplied with power and generating heat or a further allowable range from this voltage drop degree. It is.
[0132]
Then, based on the contents of this history, it is determined whether or not the battery voltage VB has actually dropped below the starting standard minimum voltage Vstannorm at the time of starting (S314). If it has decreased (“YES” in S314), it indicates that the glow plug 22 has generated heat normally, and the long start time Tsta is considered to be due to another factor different from abnormal glow energization.
[0133]
Therefore, as described above, “OFF” is set as the starting precondition (S316), and this process is temporarily terminated. As a result, the starting precondition is determined, and in step S300, “NO” is determined in the next control cycle, and the substantial process of the starting precondition calculation process (FIG. 5) is completed. Thus, the state where “OFF” is set as the precondition at the start indicates that there is no possibility of abnormal glow energization.
[0134]
On the other hand, if the battery voltage VB is not lower than the starting standard minimum voltage Vstannor at the time of starting (“NO” in S314), “ON” is set as the starting precondition (S318), and this process is finished once. . As a result, the starting precondition is determined, and in step S300, “NO” is determined in the next control cycle, and the substantial process of the starting precondition calculation process (FIG. 5) is completed.
[0135]
As described above, the state in which “ON” is set as the precondition for starting may be determined as “YES” in step S310 and “NO” in step S314 due to other factors, but it is possible that the glow energization is abnormal. It shows that there is sex.
[0136]
Next, a glow abnormality determination execution condition calculation process (FIGS. 8 and 9) for determining conditions for executing a temporary abnormality determination process (FIG. 10) and a main abnormality determination process (FIG. 11) described later will be described. This process is repeatedly executed in a time cycle. When this process is started, it is first determined whether or not the starting precondition is determined in the starting precondition calculation process (FIG. 5) (S400). If the starting precondition is not determined to be “ON” or “OFF” (“NO” in S400), this process is temporarily terminated as it is.
[0137]
If the start precondition is determined to be “ON” or “OFF” in the start precondition calculation process (FIG. 5) (“YES” in S400), then the glow abnormality determination execution permission is still permitted. It is determined whether or not the state is not made (S402). Since the glow abnormality determination execution permission is not permitted in the initial setting when the power is turned on, it is initially determined as “YES” in step S402.
[0138]
Next, it is determined whether or not the determination sensors are normal (S404). Specifically, in order to determine whether or not to permit execution of glow abnormality determination, it is determined whether or not there is an abnormality in the water temperature sensor 32, the vehicle speed sensor 48, and other sensors that require information. It is. Whether or not the sensors are normal uses, for example, data obtained by abnormality detection processing for each sensor separately executed by the ECU 52.
[0139]
If any one of these sensors is abnormal (“NO” in S404), the process is temporarily terminated as it is. As long as any one of these sensors is abnormal, accurate abnormality determination cannot be performed, so that the glow abnormality determination execution permission (S426) is not performed.
[0140]
If all the corresponding sensors are normal (“YES” in S404), then whether or not the cooling water temperature THW detected by the water temperature sensor 32 is within the determination reference temperature range (for example, 0 to 20 ° C.). Is determined (S406). This judgment reference temperature range is set according to the type of diesel engine, and it is clearly determined when the glow plug 22 generates heat normally and when the heat generation is insufficient during idle operation. It is set within a range where there is a difference in operating conditions and an appropriate range for abnormality detection. That is, if the glow energization is abnormal and the heat generation is insufficient when the temperature deviates from the determination reference temperature range to the extremely low temperature side, starting becomes difficult and the driver himself can detect an abnormality in the glow energization. Further, even if the glow plug 22 generates heat normally at such an extremely low temperature, combustion in an idle state after starting becomes unstable, and abnormality in glow energization cannot be detected with high accuracy. In addition, when the temperature is outside the determination reference temperature range, smooth engine operation is performed even if the glow plug 22 is abnormal and heat generation is insufficient, so that abnormal glow energization cannot be detected with high accuracy. .
[0141]
If the coolant temperature THW does not exist in the determination reference temperature range (“NO” in S406), the present process is temporarily terminated as it is.
On the other hand, if the coolant temperature THW is within the determination reference temperature range (“YES” in S406), then whether or not the accelerator opening ACCPF detected by the accelerator sensor 26 indicates fully closed (ACCPF = 0%). Is determined (S408). If the accelerator opening is not fully closed (“NO” in S408), that is, the injection amount is not stable unless it is in an idle operation state, the abnormality cannot be determined with high accuracy in the abnormality determination process described later. The process ends.
[0142]
On the other hand, if the accelerator opening is in the fully closed state ("YES" in S408), it is next determined whether or not the vehicle speed detected by the vehicle speed sensor 48 is "0 km / h" (S410). When the vehicle speed is not “0 km / h” (“NO” in S410), that is, when the vehicle is traveling, the fuel injection amount is not stable because it is not in an idling state, and therefore, the abnormality determination process described later is high. Since the abnormality cannot be accurately determined, the present process is temporarily terminated as it is.
[0143]
On the other hand, if the vehicle speed is “0 km / h” (“YES” in S410), it is next determined whether or not the battery voltage VB is within the determination reference voltage range (S412). This judgment reference voltage range is set according to the type of diesel engine, and there is a clear difference in the engine operating state in the fuel injection amount between when the glow is energized normally and when the glow is not energized Set to range. That is, when the voltage falls outside the reference voltage range, the load on the alternator 54 has reached 100%, and even if the glow energization is switched between on and off in this state, the engine load hardly changes. In some cases, abnormal glow energization cannot be detected with high accuracy. Further, when the voltage is outside the determination reference voltage range, the load of the alternator 54 is 0%, and even when the glow energization is switched between on and off, the engine load may hardly change. Therefore, the abnormality of glow energization cannot be detected with high accuracy.
[0144]
If the battery voltage VB does not exist in the determination reference voltage range (“NO” in S412), the present process is temporarily terminated as it is.
On the other hand, if battery voltage VB exists in the determination reference voltage range (“YES” in S412), the engine speed NE detected by NE sensor 40 and the target idle speed NTRG set by ECU 52 are next. It is determined whether or not the deviation (| NE−NTRG |) exists in the determination reference deviation range (S414). This determination reference deviation range is set corresponding to the type of diesel engine, and defines a range in which the change in the fuel injection amount due to idle speed control does not increase. This makes it possible to clearly determine the difference in fuel injection amount due to the on / off switching of glow energization in an abnormality determination process described later.
[0145]
If the deviation (| NE−NTRG |) does not exist in the determination reference deviation range (“NO” in S414), the present process is temporarily terminated.
On the other hand, if the deviation (| NE−NTRG |) is within the determination reference deviation range (“YES” in S414), it is determined whether or not the engine stabilization time has elapsed after the start is completed (S416). Immediately after the engine start is completed, the fuel injection amount tends to become unstable. For this reason, the time until the fuel injection amount can be estimated to be stabilized, that is, the engine stabilization time is set so that the difference in the fuel injection amount due to the on / off switching of glow energization can be clearly determined. In addition, since it takes time for stabilization as the temperature is low, the engine stabilization time may be set longer as the cooling water temperature THW is lower.
[0146]
If the engine stabilization time has not yet elapsed from the completion of the start (“NO” in S416), the process is temporarily terminated as it is to wait until the fuel injection amount stabilizes.
[0147]
Thereafter, if the engine stabilization time has elapsed (“YES” in S416), it is determined whether or not the remaining glow energization time executed by the glow energization control process is equal to or longer than the abnormality determination executable time. (S418). This abnormality determination executable time is preset, and glow energization is forcibly turned off once to detect a change in the engine operating state by two abnormality determination processes (FIGS. 10 and 11), which will be described later. It means the time required for returning and detecting the engine operating state change.
[0148]
If the remaining glow energization time has already fallen below the abnormality determination executable time at the time of execution of step S418 (“NO” in S418), the present process is temporarily terminated. Thereafter, an abnormality determination process (FIGS. 10 and 11), which will be described later, is not executed in the current trip.
[0149]
On the other hand, if the remaining glow energization time is equal to or longer than the abnormality determination executable time (“YES” in S418), then forcibly glow energization switching control is already performed by the abnormality determination processing (FIGS. 10 and 11) in the current trip. It is determined whether or not there is a history of execution of (S420). This is to allow only one abnormality determination process (FIGS. 10 and 11) per trip, to minimize the switching of the glow relay 22a, and to prevent the durability of the glow relay 22a from being lowered.
[0150]
If the abnormality determination process (FIGS. 10 and 11) has already been performed in the current trip (“NO” in S420), the abnormality determination process (FIGS. 10 and 11) is not executed again in this trip, so that Once this process is finished.
[0151]
Next, it is determined whether or not the start precondition is set to “ON” in the start precondition calculation process (FIG. 5) (S422). If the starting precondition is set to “OFF” (“NO” in S422), is this abnormality determination already set to “ON” in the previous trip stored in the ECU 52 next time? It is determined whether or not (S424). If this abnormality determination is not set to “ON” in the previous trip (“NO” in S424), this processing is temporarily terminated as it is.
[0152]
On the other hand, if this abnormality determination has already been set to “ON” in the previous trip (“YES” in S424), this abnormality determination is returned to “OFF” (S425), and the glow abnormality determination is executed. Is permitted (S426).
[0153]
If the starting precondition is set to “ON” (“YES” in S422), the normality determination is set to “OFF” and the glow abnormality determination execution is permitted (S426). ). That is, if “YES” is determined in step S422, there is a possibility of abnormality (“NO” in S314) in the above-described start precondition calculation process (FIG. 5), or determination of the possibility of abnormality. This is a case where it was not possible (“NO” in S301). Therefore, an abnormality determination process (FIGS. 10 and 11) described later is executed to determine the presence / absence of an abnormality.
[0154]
Further, if “YES” is determined in step S424, it is found that there is an abnormality in glow energization in the trip before the previous time, so there is a possibility that the repair has already been completed. For this reason, even if it is determined that there is no possibility of abnormality in the start precondition calculation process (FIG. 5) (S316), the abnormality determination process (FIGS. 10 and 11) described later was executed to return to a normal state by repair. Processing to leave whether or not as information.
[0155]
Next, an abnormality determination process (FIGS. 10 and 11) for forcibly switching glow energization will be described. FIG. 10 shows a temporary abnormality determination process, and FIG. 11 shows this abnormality determination process. These processes are repeatedly executed in a time cycle.
[0156]
When the temporary abnormality determination process (FIG. 10) is started, it is first determined whether or not the glow abnormality determination execution is permitted in step S426 of the above-described glow abnormality determination execution condition calculation process (FIGS. 8 and 9). (S500). If the glow abnormality determination execution is not yet permitted (“NO” in S500), the present process is temporarily terminated as it is, and no substantial process is performed.
[0157]
If the glow abnormality determination execution is permitted (“YES” in S500), then the glow abnormality determination execution is permitted and it is determined whether the process is the first process (S502). If it is the first process (“YES” in S502), then the target idle speed NTRG at this time is stored in the memory as the target idle speed NTold immediately before glow-off (S504). This is used to determine whether or not the target idle speed NTRG has changed in a glow abnormality determination stop condition calculation process (FIG. 12) described later.
[0158]
Next, the final basic injection amount command value QFINC (FIG. 4: S230) at this time is stored in the memory as the final basic injection amount command value Qold1 immediately before glow-off (S506). Then, the battery voltage VB at this time is stored in the memory as the battery voltage VBold1 immediately before glow-off (S508).
[0159]
Then, the glow energization that continues from the ignition switch on to the present is forcibly turned off (S510). As a result, the amount of electrical energy that was previously energized with glow is lost, and the consumption of the entire electrical energy is greatly reduced. For this reason, the load with respect to the diesel engine 2 falls corresponding to electric energy consumption reduction. Therefore, in the idling engine speed control executed as part of the fuel injection amount control process (FIGS. 3 and 4), the final basic injection amount command value QFINC is decreased in order to maintain the same target idling engine speed NTRG. The Further, the battery voltage VB also rises when the energization to the glow plug 22 is stopped.
[0160]
Next, in order to determine that the load on the diesel engine 2 described above has decreased normally, a change in the final basic injection amount command value QFINC under idle speed control and a change in the battery voltage VB are determined.
[0161]
First, it is determined whether or not the state satisfying the following expression 6 has continued for a time necessary to determine engine load reduction (S512).
[0162]
[Formula 6]
Qold1−QFINC ≧ dQ1 [Formula 6]
Here, the decrease determination value dQ1 is obtained by setting a minimum value corresponding to a decrease in the fuel injection amount corresponding to the reduction in electric energy consumption by experiments and the like in advance.
[0163]
If the above formula 6 is not satisfied, or if the time required for the engine load reduction determination is not continued even if the above formula 6 is satisfied (“NO” in S512), the state where the following formula 7 is satisfied is obtained. It is determined whether or not the time necessary for determining the increase in the battery voltage VB has continued (S514).
[0164]
[Expression 7]
VB−VBold1 ≧ dV1 [Equation 7]
Here, the increase determination value dV1 is obtained by previously obtaining and setting a minimum value of the increase in the battery voltage VB corresponding to glow energization OFF.
[0165]
If the expression 7 is not satisfied, or if the time required for the voltage increase determination is not continued even if the expression 7 is satisfied (“NO” in S514), the state where the following expression 8 is satisfied is the engine. It is determined whether or not the time required for determining the load unchanged state has continued (S516).
[0166]
[Equation 8]
Qold1−QFINC <dQ1 [Equation 8]
Equation 8 represents a state where Equation 6 is not satisfied.
[0167]
If the above formula 8 is not satisfied, or if the time required for the non-change determination of the engine load is not continued even if the above formula 8 is satisfied ("NO" in S516), this processing is temporarily terminated as it is. To do.
[0168]
If the state satisfying Equation 6 continues for the time necessary to determine engine load reduction ("YES" in S512), or the state satisfying Equation 7 requires time to determine an increase in battery voltage VB If it continues (“YES” in S514), the normality determination is set to “ON” (S518). That is, the state determined as “YES” in step S512 or step S514 is that the glow energization is normally performed before the forced glow energization OFF (S510), and in accordance with the command of the ECU 52 in step S510. Indicates that glow energization has been turned off. Therefore, information indicating normality determination “ON” is stored in the backup RAM in the ECU 52. In this way, this process is once completed. If the normality determination is “ON”, glow energization is turned on again by a glow abnormality determination stop condition calculation process (FIGS. 12 and 13) described later, and this abnormality determination process (FIG. 11) is executed. Not.
[0169]
On the other hand, if neither the step S512 nor the step S514 is satisfied and the state satisfying the equation 8 continues for the time necessary to determine the engine load unchanged state ("YES" in S516), the provisional abnormality determination is performed. “ON” is set (S520). That is, before the forced glow energization is turned off (S510), the glow energization is not normally turned on, or the glow energization is not turned off as instructed by the ECU 52 in step S510. Therefore, the information that the temporary abnormality determination is “ON” is stored in the backup RAM in the ECU 52. In this way, this process is once completed. Since the temporary abnormality determination is “ON” in this way, the temporary abnormality determination process (FIG. 10) is stopped by the glow abnormality determination stop condition calculation process (FIGS. 12 and 13) described later, and the abnormality determination process is performed. The substantial process (FIG. 11) is executed.
[0170]
The abnormality determination process (FIG. 11) will be described. This process is repeatedly executed in a time cycle. When this process is started, it is first determined whether or not the provisional abnormality determination is “ON” (S600). The temporary abnormality determination “OFF” set in the initial setting continues until the temporary abnormality determination is set to “ON” in the temporary abnormality determination process (FIG. 10) described above (in S600). “NO”), this process is temporarily terminated as it is, and no substantial process is performed.
[0171]
However, as described above, if the temporary abnormality determination is set to “ON” in the temporary abnormality determination process (FIG. 10) (“YES” in S600), then in step S510 of the temporary abnormality determination process (FIG. 10). It is determined whether or not a standby time has elapsed since the forced glow energization “OFF” (S601). This standby time is provided in advance in order to prevent the glow relay 22a from being switched on and off in a short time and to prevent the durability of the glow relay 22a from being lowered. This standby time varies depending on the type of glow relay 22a and the amount of current, but a time of, for example, 100 msec is set.
[0172]
While the standby time has not elapsed (“NO” in S601), the present process is temporarily terminated as it is, and the substantial process in the present abnormality determination process is not started.
When the standby time has elapsed (“YES” in S601), it is next determined whether or not the process is the first process after “YES” is determined in step S601 (S602). If it is the first process (“YES” in S602), then the final basic injection amount command value QFINC at this time is stored in the memory as the final basic injection amount command value Qold2 immediately before glow-on (S604). The battery voltage VB at this time is stored in the memory as the battery voltage VBold2 immediately before glow-on (S606).
[0173]
Then, the energization is forcibly turned on from the glow energization stop state (S608). As a result, glow energization is resumed, and the consumption of electrical energy increases greatly. For this reason, the engine load with respect to the diesel engine 2 rises corresponding to an increase in electric energy consumption. Therefore, in the idling engine speed control executed as part of the fuel injection amount control process (FIGS. 3 and 4), the final basic injection amount command value QFINC is increased in order to maintain the same target idling engine speed NTRG. . Further, the battery voltage VB also drops when the energization of the glow plug 22 is started.
[0174]
Next, in order to determine that the engine load has increased normally, a change in the final basic injection amount command value QFINC under idle speed control and a change in the battery voltage VB are determined.
[0175]
First, it is determined whether or not a state satisfying the following expression 9 has continued for a time necessary to determine an increase in engine load (S610).
[0176]
[Equation 9]
QFINC−Qold2 ≧ dQ2 (Equation 9)
Here, the increase determination value dQ2 is obtained by setting a minimum value for an increase in the fuel injection amount corresponding to an increase in electric energy consumption by an experiment or the like in advance.
[0177]
If the above formula 9 is not satisfied, or if the time required for the engine load increase determination is not continued even if the above formula 9 is satisfied (“NO” in S610), a state where the following formula 10 is satisfied is obtained. It is determined whether or not the time required for determining the drop in the battery voltage VB has continued (S612).
[0178]
[Expression 10]
VBold2−VB ≧ dV2 [Equation 10]
Here, the drop determination value dV2 is obtained by previously obtaining and setting a minimum value of the battery voltage VB drop corresponding to glow energization ON.
[0179]
If the expression 10 is not satisfied, or if the time required for the voltage drop determination is not continued even if the expression 10 is satisfied (“NO” in S612), the state where the following expression 11 is satisfied is the engine. It is determined whether or not the time required for determining the unchanged state of the load has continued (S614).
[0180]
[Expression 11]
QFINC−Qold2 <dQ2 [Equation 11]
Expression 11 represents a state where Expression 9 is not satisfied.
[0181]
If the expression 11 is not satisfied, or if the time required for the non-change determination of the engine load is not continued even if the expression 11 is satisfied (“NO” in S614), the process is temporarily terminated as it is. To do.
[0182]
If the state satisfying Equation 9 continues for the time necessary to determine an increase in engine load ("YES" in S610), or the state satisfying Equation 10 requires a time to determine a decrease in battery voltage VB If it continues ("YES" in S612), the temporary abnormality determination is returned to "OFF" (S616). That is, the state determined as “YES” in step S610 or step S612 is that the glow energization is surely turned off before the forced glow energization is turned on (S608), and as instructed by the ECU 52 in step S608. It indicates that glow energization is turned on. This indicates that the energization-off was not clearly detected in the temporary abnormality determination process (FIG. 10) even though the glow energization was actually turned off for some reason. (FIG. 11) shows that the glow plug 22 has been confirmed to function normally.
[0183]
Therefore, the temporary abnormality determination is returned to “OFF” and stored in the backup RAM in the ECU 52. In this way, this process is once completed. In the subsequent control cycle, since the temporary abnormality determination is “OFF”, the determination is “NO” in step S600, and thus the substantial process of the abnormality determination process (FIG. 11) ends. Since glow energization is turned back on, glow energization is turned off after energization for the remainder of the glow energization time by the glow energization control process started by turning on the ignition switch is continued.
[0184]
On the other hand, if neither the step S610 nor the step S612 is satisfied, and the state satisfying the expression 11 continues for a time necessary to determine the engine load unchanged state ("YES" in S614), this abnormality determination is performed. “ON” is set (S618). That is, it is shown that the abnormality is determined to be abnormal in the temporary abnormality determination process (FIG. 10) as well as the abnormality (temporary abnormality determination) in the temporary abnormality determination process (FIG. 10). Accordingly, since there is a high certainty that the glow energization is abnormal, information indicating this abnormality determination “ON” is stored in the backup RAM in the ECU 52. In this way, this process is once completed. As a result of this abnormality determination “ON”, the abnormality determination process (FIG. 11) is stopped by a glow abnormality determination stop condition calculation process (FIGS. 12 and 13) described later.
[0185]
The glow abnormality determination stop condition calculation process (FIGS. 12 and 13) will be described. This process is repeatedly executed in a time cycle, and is executed to stop the temporary abnormality determination process (FIG. 10) and the main abnormality determination process (FIG. 11).
[0186]
When this process is started, it is first determined whether or not the glow abnormality determination execution is permitted in step S426 of the above-described glow abnormality determination execution condition calculation process (FIGS. 8 and 9) (S700). If the glow abnormality determination execution is not yet permitted ("NO" in S700), this process is temporarily terminated as it is, and no substantial process is performed.
[0187]
If the glow abnormality determination execution is permitted (“YES” in S700), the same processing (S702 to S710) as steps S404 to S412 of the above-described glow abnormality determination execution condition calculation processing (FIGS. 8 and 9) is performed. . That is, it is determined whether the determination sensors are normal (S702). If the determination sensors are normal (“YES” in S702), it is determined whether or not the coolant temperature THW is within the determination reference temperature range (S704). If the coolant temperature THW is within the determination reference temperature range (“YES” in S704), it is determined whether or not the accelerator opening ACCPF is fully closed (S706). If the accelerator opening ACCPF is fully closed (“YES” in S706), it is determined whether or not the vehicle speed is “0 km / h” (S708). If the vehicle speed is “0 km / h” (“YES” in S708), it is determined whether or not the battery voltage VB is within the determination reference voltage range (S710).
[0188]
If the battery voltage VB is within the determination reference voltage range (“YES” in S710), the target idle speed control is performed in the idle speed control when the temporary abnormality determination process (FIG. 10) and the abnormality determination process (FIG. 11) are executed. It is determined whether or not the rotational speed NTRG has changed (S712). This change is made by comparing the current target idle speed NTRG with the target idle speed NTold immediately before glow-off stored in step S504 of the temporary abnormality determination process (FIG. 10).
[0189]
If the target idle speed NTRG changes, the final basic injection amount command value QFINC changes, making it difficult to distinguish it from injection amount fluctuations caused by switching on / off of glow energization. Therefore, this determination is performed in order to prevent erroneous determination in the temporary abnormality determination process (FIG. 10) and the main abnormality determination process (FIG. 11).
[0190]
If there is no change in target idle speed NTRG (“YES” in S712), it is determined whether both the normal determination and the abnormality determination are set to “OFF” (S714). Here, if both the normality determination and the abnormality determination are “OFF” (“YES” in S714), it is next determined whether or not the switches of various devices using the battery 60 as a power source have changed (S716). ). These switches are an air conditioner switch 50, an electric heater switch, a tail lamp switch, a defogger switch, a brake signal switch, and the like. If these switches are changed, the battery voltage VB and the final basic injection amount command value QFINC will change, making it difficult to distinguish them from changes due to glow energization on / off switching. Therefore, this determination is performed in order to prevent erroneous determination in the temporary abnormality determination process (FIG. 10) and the main abnormality determination process (FIG. 11).
[0191]
If there is no change in the various switches (“YES” in S716), it is next determined whether or not the provisional abnormality determination is “OFF” (S718). Here, in the state where the temporary abnormality determination process (FIG. 10) is being executed and the normal determination is “OFF” and the temporary abnormality determination is “OFF” (“YES” in S718), this process is temporarily terminated as it is. To do.
[0192]
On the other hand, if any one of the above-described steps S702 to 716 is determined to be “NO”, the temporary abnormality determination is set to “OFF” (S720). As a result, in this abnormality determination process (FIG. 11), “NO” is determined in step S600, and thus the substantial process ends.
[0193]
Then, a forced energization on process is performed in which the glow energization is turned on after the standby time has elapsed after the glow energization is switched from on to off by the execution of step S510 of the temporary abnormality determination process (FIG. 10). (S722). The standby time is the same as the standby time described in step S601 of the abnormality determination process (FIG. 11) in order to prevent the durability of the glow relay 22a from being lowered.
[0194]
In this forced glow energization ON process, if the standby time has already elapsed at the time of execution of step S722, glow energization is immediately performed. If the standby time has not yet elapsed at the time of execution of step S722, glow energization is performed after the standby time has elapsed. It should be noted that if the forced glow energization on has already been executed in step S608 of this abnormality determination (FIG. 11), the glow energization on state is maintained.
[0195]
Then, the execution of the glow abnormality determination is not permitted (S724), and this process is temporarily terminated.
Next, since the glow abnormality determination execution permission is canceled in the control cycle, it is determined as “NO” in step S700 in the glow abnormality determination stop condition calculation process (FIGS. 12 and 13), and the substantial process is not performed. Similarly, even if the temporary abnormality determination process (FIG. 10) is executed, it is determined as “NO” in step S500, and the substantial process is not performed.
[0196]
If “NO” is determined in the step S714, the step S518 of the temporary abnormality determination process (FIG. 10) is executed and the normal determination is “ON”, or the step of the present abnormality determination (FIG. 11). This is a case where S618 is executed and this abnormality determination is “ON”.
[0197]
Further, as described above, when step S520 of the temporary abnormality determination process (FIG. 10) is executed and the temporary abnormality determination is “ON” (“NO” in S718), the temporary abnormality determination process (FIG. 10) is executed. Is stopped (S726).
[0198]
An example of the processing in the present embodiment described above is shown in the timing charts of FIGS.
FIG. 14 shows a case where the starting precondition is “OFF”. Here, the ignition switch is set to “ON” at time t0. This immediately turns on glow energization. Then, the starter permission is displayed to the driver by the indicator lamp at time t1, so that the driver immediately turns the starter 30 on, thereby starting the start mode. Then, when the engine speed NE rises to a speed indicating the start completion, the completion of the start is determined by the ECU 52 (t2). The actual start time Tsta (t1 to t2) obtained at this time is equal to or shorter than the standard start time Tstannorm. In the example of FIG. 14, the battery voltage VB also has a history of lowering than the starting standard minimum voltage Vstannorm.
[0199]
Therefore, after the start is completed, “NO” is determined in step S310 of the start precondition calculation process (FIG. 5), and “OFF” is set as the precondition (S316). Therefore, thereafter, neither the temporary abnormality determination process (FIG. 10) nor the abnormality determination process (FIG. 11) is executed, and the glow energization on state continues and the energization set in the normal glow energization control is performed. When the time expires (t3), glow energization is turned off. Through the above-described processing, the starting precondition = “OFF”, the abnormality determination = “OFF”, and the normality determination = “OFF” are recorded in the memory of the ECU 52 as internal information such as diagnosis.
[0200]
The example of FIG. 15 shows a case where no current flows through the glow plug 22 due to disconnection even when glow energization is “ON”. The ignition switch is turned “ON” (t10), the starter 30 starts to be driven by permission of the starter (t11), and the engine start is completed (t12). At this time, the actual start time Tsta is longer than the standard start time Tstannorm, and the battery voltage VB has no history of lowering than the start-time standard minimum voltage Vstannorm. Therefore, “YES” is determined in step S310 and “NO” is determined in step S314 of the starting prerequisite calculation process (FIG. 5), and “ON” is set as the starting prerequisite (S318). Thus, the glow abnormality determination execution condition calculation process (FIGS. 8 and 9) is executed. When the glow abnormality determination execution is permitted (S426), a temporary abnormality determination process (FIG. 10) is executed (t13). This forcibly turns off glow energization. Immediately after the forced glow energization is turned off, in the example of FIG. 15, neither the fuel injection amount nor the battery voltage is changed even when waiting for the determination (“YES” in S516), so the temporary abnormality determination is “ON”. (S520: t14). Accordingly, the temporary abnormality determination process (FIG. 10) is stopped by step S726 of the glow abnormality determination stop condition calculation process (FIGS. 12 and 13), and instead, the substantial process of the abnormality determination process (FIG. 11) is started and forced. Thus, glow energization is driven on (S608). In the example of FIG. 15, even immediately after the forced glow energization is turned on, neither the fuel injection amount nor the battery voltage is changed even when waiting for determination (“YES” in S614). (S618: t15). In step S714 of the glow abnormality determination stop condition calculation process (FIGS. 12 and 13), the determination is “NO”, the temporary abnormality determination is “OFF” (S720), and the glow abnormality determination execution is not permitted ( S724). In step S722, forced glow energization has already been turned on, and the on state is maintained.
[0201]
Thereafter, when the energization time set in the normal glow energization control ends (t16), the glow energization is driven off. With the above-described processing, the starting precondition = “ON”, the abnormality determination = “ON”, and the normality determination = “OFF” are recorded in the memory of the ECU 52.
[0202]
The example of FIG. 16 shows an example in which it is determined to be normal in the temporary abnormality determination process (FIG. 10). The ignition switch is turned on (t20), the starter 30 starts to be driven by permission of the starter (t21), and the engine start is completed (t22). At this time, the actual starting time Tsta is longer than the standard starting time Tstannor, and the battery voltage VB has no history of lowering than the starting standard minimum voltage Vstannorm. Therefore, “YES” is determined in step S310 of the start precondition calculation process (FIG. 5), “NO” is determined in step S314, and “ON” is set as the precondition (S318). Accordingly, when the glow abnormality determination execution condition calculation process (FIGS. 8 and 9) is executed and the glow abnormality determination execution is permitted (S426), the temporary abnormality determination process (FIG. 10) is executed (t23). As a result, glow energization is forcibly driven to “OFF”. At this time, in the example of FIG. 16, the battery voltage VB is immediately increased by the increase determination value dV1 or more, and “YES” is determined in step S514. Note that the fuel injection amount is also decreased by the decrease determination value dQ1 or more.
[0203]
Therefore, the normality determination is set to “ON” (S518: t24). Accordingly, the temporary abnormality determination is maintained “OFF” (S720), the glow abnormality determination execution is not permitted (S724), and the temporary abnormality determination process (FIG. 10) is stopped. Further, the glow energization is turned on after the standby time has elapsed from the forced glow energization off (S510) by the process of step S722 (t25). For this reason, the abnormality determination process (FIG. 11) is not executed. Thereafter, when the energization time set in the normal glow energization control ends (t26), the glow energization is turned off. With the above-described processing, the starting precondition = “ON”, the abnormality determination = “OFF”, and the normality determination = “ON” are recorded in the memory of the ECU 52.
[0204]
FIG. 17 shows that when the forced glow energization is turned off in the temporary abnormality determination process (FIG. 10), the fuel injection amount and the battery voltage are not sufficiently changed, and the forced glow energization is turned on in the abnormality determination process (FIG. 11). An example in which the fuel injection amount and the battery voltage are sufficiently changed for the first time will be described. The transition from time t30 to t34 is the same as that from time t10 to t14 described in FIG. Then, glow energization is forcibly turned on in the abnormality determination process (FIG. 11) started at time t34 (S608). At this time, in the example of FIG. 17, since the fuel injection amount has previously increased more than the increase determination value dQ2 (“YES” in S610), the temporary abnormality determination is returned to “OFF” (S616: t35). Thereafter, when the energization time set in the normal glow energization control ends (t36), the glow energization is turned off. With the above-described processing, the starting precondition = “ON”, the abnormality determination = “OFF”, and the normality determination = “OFF” are recorded in the memory of the ECU 52. Note that execution of glow abnormality determination is not permitted (S724) when the accelerator pedal 24 is depressed ("NO" in S706), for example.
[0205]
FIG. 18 shows an example of when the engine is started immediately after the glow energization abnormality is found in the previous trip and the repair is completed. From time t40 to t42 changes in the same manner as from time t0 to t2 described in FIG. 14, and glow energization is normally performed in the starting precondition calculation process (FIG. 5). In step S314, “YES” is determined, and the starting precondition is set to “OFF” (S316).
[0206]
Then, at time t43, in the glow abnormality determination execution condition calculation process (FIGS. 8 and 9), if all of “YES” are determined in steps S400 to S420, it is next determined whether or not the starting precondition is “ON”. (S422). At this time, assuming that there is no possibility of abnormality in the glow plug 22, “OFF” is set in the starting precondition (“NO” in S 422), and then this abnormality determination is already set to “ON”. It is determined whether or not it has been performed (S424). Here, since this abnormality determination is already “ON” (“YES” in S424), the abnormality determination is then returned to “OFF” (S425). Then, the glow abnormality determination execution is permitted (S426), thereby starting the substantial process of the temporary abnormality determination process (FIG. 10).
[0207]
In the temporary abnormality determination process (FIG. 10), glow energization is forcibly driven off. At this time, since glow energization is normally turned off, the battery voltage VB immediately rises by the increase determination value dV1 or more and it is determined as “YES” in step S514 (t44). Note that the fuel injection amount is also decreased by the decrease determination value dQ1 or more.
[0208]
Therefore, the normality determination is set to “ON” (S518). Therefore, it is determined as “NO” in step S714, the temporary abnormality determination is maintained “OFF” (S720), the glow abnormality determination execution is not permitted (S724), and the temporary abnormality determination process (FIG. 10) is stopped. Further, by the process in step S722, the glow energization is turned on after the standby time has elapsed from the forced glow energization off (S510) (t45).
[0209]
Thereafter, when the energization time set in the normal glow energization control ends (t46), the glow energization is turned off. With the above-described processing, the starting precondition = “OFF”, the abnormality determination = “OFF”, and the normality determination = “ON” are recorded in the memory of the ECU 52.
[0210]
In the configuration described above, the starting precondition calculation process (FIG. 5) includes a glow abnormality determination execution condition calculation process (FIGS. 8 and 9), a temporary abnormality determination process (FIG. 10), a process as an abnormality possibility determination unit. The abnormality determination process (FIG. 11) and the glow abnormality determination stop condition calculation process (FIGS. 12 and 13) correspond to the process as abnormality presence / absence determination means. Further, the process for counting the time from the start to the completion of the start to obtain the start time Tsta and the process for detecting the history of the battery voltage VB from the start to the completion of the start are the processes as the state detection means before the start is completed. It corresponds to. Further, the glow abnormality determination execution condition calculation process (FIGS. 8 and 9) and the temporary abnormality determination process (FIG. 10) are replaced with the first abnormality determination means, the present abnormality determination process (FIG. 11), and the glow abnormality determination stop condition calculation. The process (FIGS. 12 and 13) corresponds to a process as the second abnormality determination means.
[0211]
According to the first embodiment described above, the following effects can be obtained.
(I). Abnormality determination performed by the start precondition calculation process (FIG. 5), that is, abnormality detection performed based on the length of the start time Tsta and the state of the battery voltage VB at the start without forcibly turning on or off glow energization Is less reliable than when the glow energization is forcibly changed. This is because even if the glow plug 22 is normally energized, the start time Tsta may not be increased or the battery voltage VB may not be decreased due to other reasons.
[0212]
However, even if the glow energization is not forcibly changed, if the start time Tsta is sufficiently short when the glow energization is turned on, or if the battery voltage VB is sufficiently reduced, the glow energization may be abnormal. It can be determined with high certainty that there is no property. Therefore, when it is determined that there is no possibility of abnormality by executing the starting precondition calculation process (FIG. 5) before the temporary abnormality determination process (FIG. 10) or the main abnormality determination process (FIG. 11). This eliminates the need to execute the temporary abnormality determination process (FIG. 10) and the main abnormality determination process (FIG. 11). Determination of whether or not there is no possibility of abnormality by the start precondition calculation process (FIG. 5), that is, provisional abnormality determination that performs forced glow energization on / off when it is determined that there is a possibility of abnormality What is necessary is just to perform a process (FIG. 10) and this abnormality determination process (FIG. 11). Therefore, the number of forced changes in glow energization by driving the glow relay 22a can be suppressed.
[0213]
In this way, when it is determined that there is a possibility of abnormality, it is possible to ensure the accuracy of the glow energization abnormality determination by executing forced glow energization on / off and capturing the fuel injection amount change and the battery voltage change. At the same time, since the number of times of glow energization switching can be reduced, it is possible to suppress a decrease in durability of the glow relay 22a.
[0214]
(B). If glow energization is normally performed, the engine start is completed at an early stage, so the start time Tsta is shortened. However, if the glow energization is not normal, the start time Tsta becomes long. Therefore, in the starting precondition calculation process (FIG. 5), it can be determined that there is no possibility of abnormality of the glow plug 22 if the starting time Tsta is equal to or shorter than the standard starting time Tstannorm. Conversely, if the starting time Tsta is longer than the standard starting time Tstannor, there may be other causes, but the possibility that the glow plug 22 is abnormal cannot be denied.
[0215]
In addition, if glow energization is normally performed at the start, the battery voltage VB decreases before the start is completed. If glow energization is not performed or the energization amount is abnormally low, the battery voltage VB decreases. There is almost no. Therefore, in the starting precondition calculation process (FIG. 5), it can be determined that there is no possibility that the glow plug 22 is abnormal if the battery voltage VB is lower than the starting standard minimum voltage Vstantorum before starting is completed. On the contrary, if there is no history that the battery voltage VB has dropped below the starting standard minimum voltage Vstannor before the start is completed, there may be other causes, but the possibility that the glow plug 22 is abnormal cannot be denied.
[0216]
Therefore, if the starting time Tsta is longer than the standard starting time Tstannor and there is no history that the battery voltage VB has dropped below the starting standard minimum voltage Vstannor before completion of starting, it is determined that there is a possibility of abnormality.
[0217]
In this way, in the starting precondition calculation process (FIG. 5), it is possible to easily determine whether or not there is a possibility of abnormality without forcibly changing glow energization. In addition, the standard starting time Tstannor and the starting standard minimum voltage Vstannorm are set based on the starting cooling water temperature THWs, so that it is possible to more reliably determine whether there is an abnormality.
[0218]
(C). In the glow abnormality determination execution condition calculation process (FIGS. 8 and 9), the remainder of the glow energization time set in the normal glow energization control is changed to the temporary abnormality determination process (FIG. 10) and the present abnormality determination process (FIG. 11). Only when the length is executable ("YES" in S418), the glow abnormality determination execution is permitted.
[0219]
Thus, the provisional abnormality determination process (FIG. 10) and the present abnormality determination process (FIG. 11) can complete the abnormality presence / absence determination associated with the forced change in glow energization within the normal glow energization set time. For this reason, glow energization control is not extended by forced change of glow energization, and energy consumption due to abnormality determination can be suppressed.
[0220]
Note that the forced glow energization change by the temporary abnormality determination process (FIG. 10) and the main abnormality determination process (FIG. 11) is performed during normal glow energization. However, since the forced glow energization change is performed particularly after the engine operation state is stabilized by the glow abnormality determination execution condition calculation process (FIGS. 8 and 9), there is no problem in the stability of the engine operation after starting.
[0221]
(D). As described above, the temporary abnormality determination process (FIG. 10) and the present abnormality determination process (FIG. 11) confirm the glow energization abnormality in two stages of forced glow energization OFF and forced glow energization ON. Judgment is possible. Moreover, the glow energization state can be returned to the original glow energization ON state by this two-stage forced energization switching, and does not hinder the operation stability of the diesel engine.
[0222]
(E). If the energization off and the energization on are executed at short time intervals, the durability of the glow relay 22a may be reduced. For this reason, in this abnormality determination process (FIG. 11), forced glow energization is performed until the standby time for protecting the glow relay 22a elapses from the time of forced glow energization OFF (S510) in the temporary abnormality determination process (FIG. 10). ON is not executed (S601). This can prevent the durability of the glow relay 22a from being lowered.
[0223]
(F). In the glow abnormality determination execution condition calculation process (FIGS. 8 and 9), even if it is clear that there is no possibility of abnormality regarding glow energization (“NO” in S422), this abnormality determination is already “ If it is “ON” (“YES” in S424), the glow abnormality determination execution is permitted (S426).
[0224]
As a result, after the repair, the temporary abnormality determination process (FIG. 10) can be executed, and in some cases, this abnormality determination process (FIG. 11) can be further executed, and the internal information such as diagnosis corresponds to the normal glow energization after the repair. Can be.
[0225]
[Embodiment 2]
In this embodiment, when glow energization is turned on by normal glow energization control performed from the start, only the start precondition calculation process (FIG. 5) is executed, and the start precondition “ON” or “OFF”. Set. After the glow energization is turned on, only for the case where the precondition at start-up is “ON”, or only when this abnormality determination has already been “ON” before, it is temporarily determined for the presence / absence of abnormality. The glow energization is forcibly executed on / off.
[0226]
In the present embodiment, the process shown in FIG. 19 is executed instead of a part of the glow abnormality determination execution condition calculation process shown in FIG. 9 of the first embodiment. Further, instead of the temporary abnormality determination process (FIG. 10) and the main abnormality determination process (FIG. 11), the temporary abnormality determination process shown in FIG. 20 and the main abnormality determination process shown in FIG. 21 are executed. Further, instead of a part of the glow abnormality determination stop condition calculation process shown in FIG. 13, the process shown in FIG. 22 is executed. Other configurations and processes are the same as those in the first embodiment.
[0227]
In FIG. 19, as a condition for permitting execution of the glow abnormality determination, it is determined whether or not the standby time has elapsed after the end of the normal glow energization time instead of steps S416 and S418 in FIG. 9 (S417).
[0228]
Therefore, since the glow abnormality determination execution permission (S426) is not made unless the normal glow energization time ends, forced glow energization “OFF” and forced glow energization “ON” when normal glow energization is on. Is not executed.
[0229]
Then, after the normal glow energization time has ended, when it is determined as “YES” in steps S400 to S420 of the glow abnormality determination execution condition calculation process (FIGS. 8 and 19), the start prerequisite is “ Whether or not “ON” is determined (S422). If the start precondition set in the start precondition calculation process (FIG. 5) is “OFF” (“NO” in S422), then whether or not this abnormality determination has already been set to “ON”? It is determined whether or not (S424). If this abnormality determination is “OFF” (“NO” in S424), this processing is temporarily terminated as it is. Therefore, forced glow energization “ON” and “OFF” are not executed within the same trip. In this case, the transition is the same as the timing chart shown in FIG. 14 of the first embodiment.
[0230]
A case where the start precondition is determined to be “ON” in the start precondition calculation process (FIG. 5) will be described. In this case, neither the forced glow energization “OFF” nor the forced glow energization “ON” is executed within the normal glow energization time. For example, as shown in the timing chart of FIG. 23, it is assumed that the ignition switch is turned on (t50), the starter 30 starts to be driven by permission of the starter (t51), and the engine start is completed (t52). At this time, the actual start time Tsta is longer than the standard start time Tstannorm, and the battery voltage VB has no history of lowering than the start-time standard minimum voltage Vstannorm. Therefore, “YES” is determined in step S310 of the start precondition calculation process (FIG. 5), “NO” is determined in step S314, and “ON” is set as the precondition (S318). However, the temporary abnormality determination process (FIG. 20) is not immediately started, and the normal glow energization time is awaited.
[0231]
After the normal glow energization time is completed (from t53), when “YES” is determined in steps S400 to S420 of the glow abnormality determination execution condition calculation process (FIGS. 8 and 19), the next start-up is performed. It is determined whether or not the precondition is “ON” (S422). Here, since the starting precondition is “ON” (“YES” in S422), the normal determination is set to “OFF” (S423), and then the glow abnormality determination execution is permitted (S426: t54). As a result, the provisional abnormality determination process (FIG. 20) is started, “YES” is determined in step S800, “YES” is determined in step S802, and forced glow energization is turned on after the processes in steps S804 to S808. (S810). Steps S800 to S808 are substantially the same as steps S500 to S508 of the temporary abnormality determination process (FIG. 10) of the first embodiment.
[0232]
Then, it is determined whether or not the state satisfying the following expression 12 has continued for a time necessary to determine an increase in engine load (S812).
[0233]
[Expression 12]
QFINC−Qold3 ≧ dQ3 [Equation 12]
Here, the increase determination value dQ3 is obtained by setting a minimum value corresponding to an increase in the fuel injection amount corresponding to the increase in electric energy consumption through experiments or the like in advance.
[0234]
If the expression 12 is not satisfied, or if the time required for the engine load increase determination is not continued even if the expression 12 is satisfied (“NO” in S812), the state where the following expression 13 is satisfied is obtained. It is determined whether or not the time required for determining the drop in the battery voltage VB has continued (S814).
[0235]
[Formula 13]
VBold3−VB ≧ dV3 [Equation 13]
Here, the drop determination value dV3 is obtained by previously obtaining and setting the minimum value of the battery voltage VB drop corresponding to glow energization ON.
[0236]
If the expression 13 is not satisfied, or if the time required for the voltage drop determination is not continued even if the expression 13 is satisfied (“NO” in S814), the state where the following expression 14 is satisfied is the engine. It is determined whether or not the time necessary for determining the unchanged state of the load has continued (S816).
[0237]
[Expression 14]
QFINC−Qold3 <dQ3 [Formula 14]
Expression 14 represents a state where Expression 12 is not satisfied.
[0238]
If the expression 14 is not satisfied, or if the time required for the non-change determination of the engine load is not continued even if the expression 14 is satisfied (“NO” in S816), the process is temporarily terminated as it is. To do.
[0239]
As shown in the timing chart of FIG. 23, when neither the step S812 nor the step S814 is satisfied, the state satisfying the equation 14 continues for the time necessary to determine the unchanged state of the engine load (“ YES ”: t55), the temporary abnormality determination is set to“ ON ”(S820). That is, before the forced glow energization is turned on (S810), the glow energization that should have been turned off remains in the on state, or the glow energization has not been turned on as instructed by the ECU 52 (S810). Show. Therefore, the information that the temporary abnormality determination is “ON” is stored in the backup RAM in the ECU 52. In this way, this process is once completed.
[0240]
Since the temporary abnormality determination is “ON” in this way, the temporary abnormality determination process (FIG. 20) is stopped by the glow abnormality determination stop condition calculation process (FIGS. 12 and 22) (S726), and this abnormality determination process ( The substantial process of FIG. 21) is executed (“YES” in S900).
[0241]
In this abnormality determination process (FIG. 21), glow energization is forcibly turned off after the processes of steps S900 to S906 (S908). Steps S900 to S906 are substantially the same as steps S600 to 606 of the provisional abnormality determination process (FIG. 11) of the first embodiment, although there is a difference between glow energization on and off.
[0242]
Next, in order to determine that the load on the diesel engine 2 described above has decreased normally, a change in the final basic injection amount command value QFINC under idle speed control and a change in the battery voltage VB are determined.
[0243]
First, it is determined whether or not the state satisfying the following expression 15 has continued for a time necessary to determine a decrease in engine load (S910).
[0244]
[Expression 15]
Qold4-QFINC ≧ dQ4 [Equation 15]
Here, the decrease determination value dQ4 is obtained by previously obtaining and setting a minimum value for a decrease in the fuel injection amount corresponding to the reduction in electric energy consumption.
[0245]
If the expression 15 is not satisfied, or if the time required for load reduction determination is not continued even if the expression 15 is satisfied (“NO” in S910), the state where the following expression 16 is satisfied is the battery. It is determined whether or not the time required to determine the increase in voltage VB has continued (S912).
[0246]
[Expression 16]
VB−VBold4 ≧ dV4 [Equation 16]
Here, the rise determination value dV4 is obtained by setting in advance an experiment or the like as a minimum value of the rise in the battery voltage VB corresponding to the glow energization off.
[0247]
If the expression 16 is not satisfied, or if the time required for the voltage increase determination is not continued even if the expression 16 is satisfied (“NO” in S912), the state where the following expression 17 is satisfied is the engine. It is determined whether or not the time necessary for determining the unchanged state of the load has continued (S914).
[0248]
[Expression 17]
Qold4-QFINC <dQ4 [Equation 17]
Expression 17 represents a state where Expression 15 is not satisfied.
[0249]
If the equation 17 is not satisfied, or if the time required for the non-change determination of the engine load is not continued even if the equation 17 is satisfied (“NO” in S914), the process is temporarily terminated as it is. To do.
[0250]
As shown in the timing chart of FIG. 23, when neither the step S910 nor the step S912 is satisfied, the state satisfying the equation 17 continues for the time necessary to determine the unchanged state of the engine load (“YES” in S914). : T56), this abnormality determination is set to "ON" (S918). That is, before the forced glow energization is turned off (S908), the glow energization is not normally performed or the glow energization is not turned off as instructed by the ECU 52 (S908). .
[0251]
In addition to the determination that there is an abnormality in the temporary abnormality determination process (FIG. 20) (temporary abnormality determination), it is determined that there is an abnormality also in this abnormality determination process (FIG. 21). Therefore, there is a high certainty that the abnormality is abnormal, and information indicating this abnormality determination “ON” is stored in the backup RAM in the ECU 52. In this way, this process is once completed.
[0252]
As a result of this abnormality determination being “ON”, it is determined “NO” in step S714 of the glow abnormality determination stop condition calculation process (FIGS. 12 and 22), and execution of the glow abnormality determination is not permitted (S724). ), The abnormality determination process (FIG. 21) is stopped. By the above-described processing, the starting precondition = “ON”, the abnormality determination = “ON”, and the normality determination = “OFF” are recorded in the memory of the ECU 52 as internal information such as diagnosis.
[0253]
Next, a case where the normality determination is set to “ON” in the timing chart of FIG. 24 will be described. From time t60 to t64, the transition is similar to the time t50 to t54 in the case of FIG. Then, in the temporary abnormality determination process (FIG. 20) started from time t64, forced glow energization is turned on (S810). When the forced glow energization “ON” actually starts to normally flow through the glow plug 22, the fuel injection amount starts increasing and the battery voltage VB starts decreasing. At time t65, the relationship of Equation 13 is first established and continues for a necessary time (“YES” in S814), so that the normality determination is “ON” (S818). Since the normal determination is “ON” as described above, “NO” is determined in step S714 of the glow abnormality determination stop condition calculation process (FIGS. 12 and 22), and the temporary abnormality determination is “OFF” (S720). The execution of the glow abnormality determination is not permitted (S724). For this reason, the temporary abnormality determination process (FIG. 20) and this abnormality determination process (FIG. 21) are stopped. Further, the glow energization is turned off after the standby time has elapsed (S723: t66).
[0254]
With the above-described processing, the starting precondition = “ON”, the abnormality determination = “OFF”, and the normality determination = “ON” are recorded in the memory of the ECU 52.
Next, the case where the glow energization change is normally performed for the first time in the abnormality determination process (FIG. 21) will be described with reference to the timing chart of FIG. From time t70 to t74, the transition is similar to the time t50 to t54 in the case of FIG. Then, in the temporary abnormality determination process (FIG. 20) started from time t74, forced glow energization is turned on (S810). When the forced glow energization is turned on, no current flows through the glow plug 22, so that the equations 12 and 13 are not satisfied, and the state where the equation 14 is satisfied continues ("YES" in S816). ": T75). Therefore, the temporary abnormality determination is set to “ON” (S820). When the provisional abnormality determination is “ON”, the provisional abnormality determination process (FIG. 20) is stopped (S726), and in this abnormality determination process (FIG. 21), the glow in step S810 of the provisional abnormality determination process (FIG. 20) is performed. Forcible glow energization OFF is executed after a standby time from energization ON (S908: t76).
[0255]
When the current that has been flowing to the glow plug 22 is normally stopped by this forced glow energization off, the fuel injection amount starts to decrease and the battery voltage VB starts to increase. Then, at time t77, when the relationship of Equation 16 is first established and continues (“YES” in S912), the temporary abnormality determination is returned to “OFF” (S916). As described above, when the provisional abnormality determination is “OFF”, the abnormality determination process (FIG. 21) substantially stops (“NO” in S900). With the above-described processing, the starting precondition = “ON”, the abnormality determination = “OFF”, and the normality determination = “OFF” are recorded in the memory of the ECU 52. Note that execution of glow abnormality determination is not permitted (S724) when the accelerator pedal 24 is depressed ("NO" in S706), for example.
[0256]
FIG. 26 shows an example of starting the engine immediately after the glow energization abnormality is found in the previous trip and the repair is completed. From time t80 to t83, the transition is similar to that from time t0 to t3 described with reference to FIG. During this time, since the glow energization is normally performed in the start precondition calculation process (FIG. 5), “NO” is determined in step S310 or “YES” in step S314, and the start precondition is set to “OFF”. (S316: t82).
[0257]
Then, after the normal glow energization process is completed (t83-), if the conditions of steps S400 to S420 of the glow abnormality determination execution condition calculation process (FIGS. 8 and 19) are satisfied, then the starting precondition is “ON”. It is determined whether or not (S422). Here, since the starting precondition is “OFF” (“NO” in S422), it is next determined whether or not the abnormality determination is already set to “ON” in the previous trip (S424). . Here, since the abnormality determination is already “ON” (“YES” in S424), the abnormality determination is returned to “OFF” (S425), and glow abnormality determination execution is permitted (S426: t84). As a result, the temporary abnormality determination process (FIG. 20) is executed, and the state in which the expression 13 is satisfied at time t85 is continued (“YES” in S814), so that the normal determination is set to “ON”. (S818).
[0258]
Accordingly, “NO” is determined in step S714 in FIG. 22, and glow energization is forcibly turned “OFF” after the standby time by the process in step S723 (t86). In addition, the temporary abnormality determination process (FIG. 20) and the actual abnormality determination process (FIG. 21) are substantially stopped by the temporary abnormality determination “OFF” (S720) and the glow abnormality determination execution disapproval (S724). . With the above-described processing, the starting precondition = “OFF”, the abnormality determination = “OFF”, and the normality determination = “ON” are recorded in the memory of the ECU 52.
[0259]
In the configuration described above, glow abnormality determination execution condition calculation processing (FIGS. 8 and 19), provisional abnormality determination processing (FIG. 20), main abnormality determination processing (FIG. 21), and glow abnormality determination stop condition calculation processing (FIGS. 12 and 22). Corresponds to processing as an abnormality presence / absence determination means. Also, the glow abnormality determination execution condition calculation process (FIGS. 8 and 19) and the temporary abnormality determination process (FIG. 20) are replaced with the first abnormality determination means, the present abnormality determination process (FIG. 21) and the glow abnormality determination stop condition calculation. The process (FIGS. 12 and 22) corresponds to a process as the second abnormality determination means. The abnormality possibility determination means and the pre-start completion state detection means are the same as those in the first embodiment.
[0260]
According to the second embodiment described above, the following effects can be obtained.
(I). The same effects as (a), (b), and (d) to (f) of the first embodiment are produced.
[0261]
(B). Since the temporary abnormality determination process (FIG. 20) and this abnormality determination process (FIG. 21) are executed after the normal glow energization time is completed, the normal glow energization control is not affected at all. For this reason, engine operation after starting can be further stabilized, especially during cold weather.
[0262]
This glow energization abnormality detection is not performed within the normal glow energization time, so even if the diesel engine is already warmed up and the normal glow energization time is short, there is an opportunity to detect an abnormality in glow energization. Fully obtained.
[0263]
[Other embodiments]
(A). The history of the battery voltage VB in the starting precondition calculation process (FIG. 5) is the history at the time of starting (from the start of the start to the completion of the start). For example, the history of the period from the ignition switch on to the start of the start is also included. The history of the battery voltage VB immediately after the start of the diesel engine 2 may be included. Further, it may be limited to the history of the battery voltage VB from the time when the ignition switch is turned on to the start of the start, or may be limited to the history of the battery voltage VB after the start of the diesel engine 2 is completed.
[0264]
(B). In the starting precondition calculation process (FIG. 5), the starting time Tsta and the history of the battery voltage VB are used to determine the starting precondition. In addition to this, “ON” / “OFF” of the starting precondition may be determined only by the starting time Tsta, and “ON” / “OFF” of the starting precondition is determined only by the history of the battery voltage VB. You may judge.
[0265]
In addition, the start precondition is “OFF” when either of the condition that the start time Tsta is equal to or less than the standard start time Tstannor and the condition that the battery voltage VB is lower than the start minimum standard voltage Vstannor is satisfied. Had been. In addition, the start precondition may be set to “OFF” when both of the two conditions are satisfied, and may be set to “ON” when both are not satisfied.
[0266]
(C). In the glow abnormality determination execution condition calculation process (FIGS. 8, 9, and 19), when the diesel engine 2 is idle, the glow abnormality determination execution is permitted (S426), the temporary abnormality determination process (FIGS. 10 and 20), and the main abnormality. The determination process (FIGS. 11 and 21) is executed. In addition to this, even if it is not idle, execution of the temporary abnormality determination process (FIGS. 10 and 20) and the present abnormality determination process (FIGS. 11 and 21) may be permitted as long as the state conforms to the idle time. For example, when the clutch is disengaged during downhill traveling or inertia traveling and power is not transmitted from the diesel engine to the wheels, provisional abnormality determination processing (FIGS. 10 and 20) and this abnormality are performed on the condition of stable rotation. The determination process (FIGS. 11 and 21) may be executed.
[0267]
(D). In the provisional abnormality determination process (FIGS. 10 and 20) and the present abnormality determination process (FIGS. 11 and 21), a normal determination is made when a sufficient change occurs in accordance with the glow energization switching in either the fuel injection amount or the battery voltage. “ON” or temporary abnormality determination “OFF” was set. In addition to this, a change in only the fuel injection amount may be determined, or a change in only the battery voltage may be determined.
[0268]
In the above determination process, it is determined that the fuel injection amount does not change sufficiently and is set to the temporary abnormality determination “ON” or the main abnormality determination “ON”. However, the battery voltage does not change sufficiently other than this. You may determine that. Alternatively, it may be determined that neither the fuel injection amount nor the battery voltage changes sufficiently.
[0269]
A change in the control duty DF with respect to the alternator 54 may be regarded as a change in the operating state of the diesel engine 2 together with or instead of the fuel injection amount and the battery voltage. That is, when a sufficient change in the control duty DF occurs due to the forced glow energization switching, the normal determination “ON” or the temporary abnormality determination “OFF” is set, and the temporary abnormality determination “ You may set to "ON" or this abnormality determination "ON".
[0270]
In addition, the final basic injection amount command value QFINC is used as the fuel injection amount to be determined in the temporary abnormality determination and the main abnormality determination. Instead, the basic injection amount command value QBASE, the governor injection amount command value is used instead. QGOV or idle injection amount correction value QII may be used.
[0271]
In addition to the fuel injection amount, the battery voltage, and the control duty, any judgment can be made in the temporary abnormality determination or the main abnormality determination as long as it is an indicator of changes in the operating state of the diesel engine such as the engine load. it can.
[0272]
(E). This abnormality determination is set to “ON” in both the temporary abnormality determination process (FIGS. 10 and 20) and the main abnormality determination process (FIGS. 11 and 21) because the fuel injection amount change and the battery voltage change due to the glow energization switching are both. It was a case where it did not occur sufficiently. In addition to this, only the provisional abnormality determination process (FIGS. 10 and 20) is executed, and when the change in glow energization is sufficiently changed in either the fuel injection amount or the battery voltage, the normal determination is “ON”. If the fuel injection amount does not change sufficiently, the abnormality determination may be “ON”.
[0273]
(F). In the first embodiment, the forced glow energization switching for abnormality detection is limited to execution within the normal glow energization on period. In addition to this, the first embodiment and the second embodiment may be combined.
[0274]
For example, when the forced glow energization switching for abnormality detection cannot be performed within the normal glow energization on period, when the normal glow energization on period elapses and the engine enters the idle operation state, The abnormality determination may be executed by executing forced glow energization on and off as in the second embodiment. By doing in this way, the abnormality determination by forced glow energization can be executed as soon as possible and surely as compared with the first and second embodiments.
[0275]
(G). In each of the above embodiments, the cooling water temperature is used as a temperature factor. Instead, the temperature of the engine oil may be used, and the engine temperature is estimated and used based on the balance between heat generation and heat dissipation due to combustion in the diesel engine. May be.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram showing an accumulator diesel engine and a control system thereof according to a first embodiment.
FIG. 2 is a power supply system diagram to the glow plug according to the first embodiment.
FIG. 3 is a flowchart of a fuel injection amount control process according to the first embodiment.
FIG. 4 is a flowchart of a fuel injection amount control process.
FIG. 5 is a flowchart of a starting precondition calculation process.
FIG. 6 is an explanatory diagram of a map structure for obtaining a standard start time Tstantorm from a start start coolant temperature THWs in the start precondition calculation process.
FIG. 7 is an explanatory diagram of a map configuration for obtaining a starting standard minimum voltage Vstantorum from a starting start cooling water temperature THWs in the starting precondition calculation process.
FIG. 8 is a flowchart of glow abnormality determination execution condition calculation processing according to the first embodiment;
FIG. 9 is a flowchart of a glow abnormality determination execution condition calculation process.
FIG. 10 is a flowchart of a temporary abnormality determination process.
FIG. 11 is a flowchart of the abnormality determination process.
FIG. 12 is a flowchart of a glow abnormality determination stop condition calculation process.
FIG. 13 is a flowchart of a glow abnormality determination stop condition calculation process.
14 is a timing chart illustrating an example of control according to Embodiment 1. FIG.
FIG. 15 is a timing chart that similarly shows an example of control.
FIG. 16 is a timing chart that similarly shows an example of control.
FIG. 17 is a timing chart that similarly shows an example of control.
FIG. 18 is a timing chart that similarly shows an example of control.
FIG. 19 is a partial flowchart of glow abnormality determination execution condition calculation processing according to the second embodiment;
FIG. 20 is a flowchart of temporary abnormality determination processing in the same manner.
FIG. 21 is a flowchart of the abnormality determination process.
FIG. 22 is a partial flowchart of the glow abnormality determination stop condition calculation process.
23 is a timing chart illustrating an example of control according to Embodiment 2. FIG.
FIG. 24 is a timing chart that similarly shows an example of control.
FIG. 25 is a timing chart illustrating an example of control.
FIG. 26 is a timing chart showing an example of control.
[Explanation of symbols]
2 ... Accumulation type diesel engine (common rail type diesel engine), 2a ... crankshaft, 2b ... belt, 4 ... injector, 4a ... solenoid valve, 6 ... common rail, 8 ... supply piping, 8a ... check valve, 10 ... supply pump DESCRIPTION OF SYMBOLS 10a ... Discharge port, 10b ... Intake port, 10c ... Pressure control valve, 10d ... Return port, 12 ... Fuel tank, 14 ... Filter, 16 ... Return piping, 18 ... Intake passage, 18a ... Intake valve, 20 ... Exhaust passage , 20a ... exhaust valve, 22 ... glow plug, 22a ... glow relay, 24 ... accelerator pedal, 26 ... accelerator sensor, 30 ... starter, 30a ... starter switch, 32 ... water temperature sensor, 34 ... oil temperature sensor, 36 ... fuel temperature Sensor: 38 ... Fuel pressure sensor, 40 ... NE sensor, 42 ... Cylinder discrimination sensor, 44 ... Transmission Down, 46: shift position sensor, 48 ... vehicle speed sensor, 50 ... air conditioner switch, 52 ... ECU, 54 ... Alternator, 54a ... Voltage regulator 56 ... air conditioner compressor, 58 ... alternator controller, 60 ... battery.

Claims (46)

A method for detecting an abnormality of a glow plug provided in a diesel engine by executing an abnormality presence / absence determination of the glow plug based on a phenomenon caused by forcibly changing an energization state of the glow plug,
Prior to the abnormality determination, a glow plug abnormality possibility determination is performed based on a phenomenon that has occurred without forcibly changing the glow plug energization state, and there is no possibility of abnormality in the abnormality possibility determination. If it is determined, the abnormality detection method of the glow plug is characterized by not performing the abnormality presence / absence determination. 2. The glow plug abnormality detection method according to claim 1, wherein the forced change of the energization state is switching between energization on and off of the glow plug. 3. The abnormality possibility determination according to claim 1, wherein the abnormality possibility determination is performed by determining a possibility of abnormality of the glow plug based on an engine state before completion of starting of the diesel engine under an energization on state of the glow plug. Glow plug abnormality detection method. 4. The glow plug abnormality detection method according to claim 3, wherein the engine state before completion of starting of the diesel engine is a length of start time. 5. The abnormality possibility determination according to claim 4, wherein when the start time is shorter than a determination reference time, it is determined that there is no abnormality, and when the start time is longer than the determination reference time, it is determined that there is a possibility of abnormality. An abnormality detection method for a glow plug, characterized by: 4. The glow plug abnormality detection method according to claim 3, wherein the engine state before completion of starting of the diesel engine is a high battery voltage. In claim 6, in the determination of the possibility of abnormality, if the battery voltage has dropped below the determination reference voltage before the completion of starting the diesel engine, it is determined that there is no possibility of abnormality, and if it has never decreased A method for detecting an abnormality of a glow plug, characterized by determining that there is a possibility of abnormality. 4. The glow plug abnormality detection method according to claim 3, wherein the engine state before the start of the diesel engine is a length of a start time and a high battery voltage. 9. The abnormality possibility determination according to claim 8, wherein if the start time is shorter than a determination reference time or if the battery voltage has dropped below the determination reference voltage, it is determined that there is no possibility of abnormality, and the start A glow plug abnormality detection method comprising: determining that there is a possibility of abnormality when the time is longer than a determination reference time and the battery voltage has never dropped below the determination reference voltage. 10. The glow plug abnormality detection method according to claim 5, wherein the determination reference time is set according to a cooling water temperature. 10. The glow plug abnormality detection method according to claim 7, wherein the determination reference voltage is set according to a cooling water temperature. In any one of Claims 1-11, when it is determined that there is a possibility of abnormality in the abnormality possibility determination, the energization on the glow plug started for starting the diesel engine is performed within the set time of energization. An abnormality detection method for a glow plug, wherein the abnormality presence / absence determination is not executed when the abnormality presence / absence determination cannot be completed. 13. The glow plug according to claim 1, wherein when the possibility of abnormality is determined in the abnormality possibility determination, the abnormality presence / absence determination is not executed except during idle speed control. Anomaly detection method. 14. The method according to claim 1, wherein when the possibility of abnormality is determined in the abnormality possibility determination, the abnormality presence / absence determination is not executed when the battery voltage is outside the determination reference voltage range. Glow plug abnormality detection method. The glow plug according to any one of claims 1 to 14, wherein in the abnormality presence / absence determination, the presence / absence of an abnormality of the glow plug is determined based on a change in an operating state of the diesel engine accompanying a forced change in an energization state of the glow plug. Plug abnormality detection method. In claim 15, in the abnormality presence determination, a first forced change of the energization state of the glow plug is performed, and a first determination is performed based on a change in operating state of the diesel engine accompanying the first forced change, When it is determined to be normal by the first determination, the abnormality presence / absence determination is terminated and the energized state is returned to before the first forced change, and the energized state is not determined to be normal by the first determination. The second forcible change is made to return before the first forcible change, and the second determination is executed based on the change in the operating state of the diesel engine accompanying the second forcible change. A glow plug characterized in that when it is determined that there is an abnormality, the abnormality presence / absence determination is terminated, and when it is not determined that there is an abnormality in the second determination, the abnormality presence / absence determination is terminated without determining the determination. Anomaly detection method. 17. The method according to claim 16, wherein the first forced change is a process of changing to energization off and the second forced change is a process of changing to energization on if the abnormality is determined. To detect abnormal glow plugs. 17. When determining whether or not there is an abnormality, the first forced change is a process of changing to energization on and the second forced change is a process of changing to energization off when the abnormality is determined. To detect abnormal glow plugs. 19. The glow plug abnormality detection according to claim 17 or 18, wherein when the first forced change is executed, the second forced change is not executed unless a preset time interval has elapsed. Method. 20. The glow plug abnormality detection method according to claim 15, wherein the change in operating state of the diesel engine is a change in engine load. 21. The glow plug abnormality detection method according to claim 20, wherein a change in engine load is detected by a change in fuel injection amount during idle speed control. 20. The glow plug abnormality detection method according to claim 15, wherein the change in the operating state of the diesel engine is a change in battery voltage. 20. The glow plug abnormality detection method according to claim 15, wherein the change in the operating state of the diesel engine is a change in fuel injection amount and a change in battery voltage. A device for detecting an abnormality of a glow plug provided in a diesel engine,
An abnormality possibility determination means for performing an abnormality possibility determination of the glow plug based on a phenomenon that has occurred without forcibly changing the energization state of the glow plug;
When it is determined by the abnormality possibility determination means that there is a possibility of abnormality in the glow plug, based on a phenomenon that occurs in response to the forced change by forcibly changing the energization state of the glow plug. The abnormality determination of the glow plug is performed, and when the abnormality possibility determination means determines that there is no possibility of abnormality in the glow plug, the abnormality determination with the forced change of the energization state of the glow plug is performed. Means for determining whether or not there is an abnormality
An abnormality detection device for a glow plug, comprising: 25. The glow plug abnormality detection device according to claim 24, wherein the forced change of the energization state is switching between energization on and off of the glow plug. 26. The abnormality possibility determination unit according to claim 24, wherein the abnormality possibility determination unit includes a pre-start completion state detection unit that detects an engine state before completion of starting a diesel engine, and the pre-start completion state is in an energized-on state of a glow plug. An abnormality detecting device for a glow plug, wherein the possibility of abnormality of a glow plug is determined based on an engine state before completion of starting a diesel engine detected by a detecting means. 27. The glow plug abnormality detection device according to claim 26, wherein the pre-start completion state detection means detects a length of start time as an engine state before the diesel engine start is completed. The abnormality possibility determination means according to claim 27, when the start time detected by the pre-start completion state detection means is shorter than the determination reference time, determines that there is no possibility of abnormality of the glow plug, and when the start time is longer An abnormality detection device for a glow plug, characterized by determining that there is a possibility of an abnormality of the glow plug. 27. The glow plug abnormality detection device according to claim 26, wherein the pre-start completion state detection means detects a battery voltage level as an engine state before the diesel engine start completion. 30. The abnormality possibility determination means according to claim 29, wherein the abnormality possibility determination means may be abnormal if the battery voltage detected by the pre-start completion state detection means has fallen below a determination reference voltage before completion of starting the diesel engine. An abnormality detecting device for a glow plug, characterized in that it is determined that there is no possibility and that there is a possibility of abnormality if it has never been lowered. 27. The glow plug abnormality detection device according to claim 26, wherein the state detection means before starting completion detects the length of the starting time and the height of the battery voltage as the engine state before completion of starting the diesel engine. . In Claim 31, the abnormality possibility determination means determines that there is no possibility of abnormality when the start time is shorter than the determination reference time or the battery voltage has dropped below the determination reference voltage, An apparatus for detecting an abnormality of a glow plug, characterized in that a start-up time is longer than a determination reference time, and that there is a possibility of abnormality when the battery voltage has never dropped below the determination reference voltage. 33. The glow plug abnormality detection device according to claim 28 or 32, wherein the abnormality possibility determination means sets the determination reference time according to a cooling water temperature. 33. The glow plug abnormality detection device according to claim 30 or 32, wherein the abnormality possibility determination means sets the determination reference voltage in accordance with a cooling water temperature. 35. The power supply to the glow plug started for start-up is started when the abnormality determination unit determines that there is a possibility of abnormality in the abnormality possibility determination unit. An abnormality detection device for a glow plug, wherein the abnormality presence / absence determination is not executed when the abnormality presence / absence determination cannot be completed within a set time. 36. The abnormality presence / absence determination means according to claim 24, wherein the abnormality presence / absence determination means executes the abnormality presence / absence determination at times other than idle speed control when the abnormality possibility determination means determines that there is a possibility of abnormality. An abnormality detection device for a glow plug, characterized by not. The abnormality determination unit according to any one of claims 24 to 36, wherein the abnormality presence / absence determination unit determines that the abnormality possibility determination unit determines that there is a possibility of abnormality and the battery voltage is outside a determination reference voltage range. An abnormality detecting device for a glow plug, characterized by not performing the operation. The abnormality determination unit according to any one of claims 24 to 37, wherein the abnormality presence / absence determining means determines whether or not there is an abnormality in the glow plug based on a change in an operating state of the diesel engine accompanying a forced change in an energization state of the glow plug. Glow plug abnormality detection device. In Claim 38, the abnormality presence determination means comprises:
When it is determined by the abnormality possibility determination means that there is a possibility of abnormality in the glow plug, the first forced change of the energization state of the glow plug is performed, and the operation state of the diesel engine accompanying the first forced change First abnormality determination means for performing determination based on the change;
If it is determined that the first abnormality determination means is normal, the abnormality presence / absence determination is terminated, the energized state is returned to before the first forced change, and it can be determined that the first abnormality determination means is normal. If not, a second forced change is made to return the energized state to before the first forced change, and a determination is performed based on a change in the operating state of the diesel engine accompanying the second forced change. A second abnormality determination means for ending the abnormality presence / absence determination without deciding a determination when the abnormality is not determined in the determination when the abnormality is determined;
An abnormality detection device for a glow plug, comprising: 40. The process according to claim 39, wherein the first forced change by the first abnormality determining means is a process of changing to energization off if the energization is already on at the start of processing of the abnormality presence / absence determining means. The glow plug abnormality detecting device according to claim 1, wherein the second forced change by the abnormality determining means is a process of changing to energization on. 40. The process of claim 39, wherein the first forced change by the first abnormality determining means is a process of turning on the current if the energization is already off at the start of the processing of the abnormality presence / absence determining means. The glow plug abnormality detection device according to claim 1, wherein the second forced change by the abnormality determination means is a process of changing the energization to off. In Claim 40 or 41, when said 1st abnormality determination means performs said 1st forced change, said 2nd abnormality determination means is said 2nd, if the preset time interval has not passed. An abnormality detecting device for a glow plug characterized by not performing forced change. 43. The glow plug abnormality detection device according to claim 38, wherein the change in the operating state of the diesel engine is a change in an engine load. 44. The glow plug abnormality detection device according to claim 43, wherein the abnormality presence / absence determination means catches a change in engine load due to a change in fuel injection amount during idle speed control. 43. The glow plug abnormality detection device according to claim 38, wherein the change in the operating state of the diesel engine is a change in battery voltage. 43. The glow plug abnormality detection device according to claim 38, wherein the change in operating state of the diesel engine is a change in fuel injection amount and a change in battery voltage.

Images