JP3610972B2 - Vehicle driving force control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To dissolve the generated power shortage of a generator caused by the drop of a gear ratio in the case of driving a driven wheel with power generated by the generator. <P>SOLUTION: A front wheel is driven by an engine 2 via an automatic transmission 4, a rear wheel is driven via an electromagnetic clutch 12 by a DC motor 3, and the DC motor 3 is driven with power generated by a generator 7. This driving force controller dissolves the generated power shortage of the generator 7 by reducing and compensating the objective value Ifm of a motor field current computed based on the rotational speed of a motor, thereby lowering a counter electromotive force generated in the electric motor 3, when it is detected that a reverse range at a gear ratio smaller than that at a first speed gear position in a drive range where the automatic transmission 4 comes to a maximum gear ratio is selected by a shift position sensor 25. <P>COPYRIGHT: (C)2004,JPO

Description

ここで、Ｖｇは発電機７の電圧、Ｉａは発電機７の電機子電流、Ｎｇは発電機７の回転数、Ｋ２は係数、Ｋ３は効率である。
【００２９】
ステップＳ６では、下記（６）式に基づき、余剰トルクつまり発電機７で負荷すべき発電負荷トルク目標値Ｔｇｔを求めてから処理を終了して目標トルク制限部８Ｆの処理に移行する。
Ｔｇｔ＝ＴＧ＋ＴΔＶＦ …………（６）
次に、目標トルク制限部８Ｆの処理について、図６に基づいて説明する。
【００３０】
すなわち、まず、ステップＳ１１で、発電負荷トルク目標値Ｔｇｔが、発電機７の最大負荷容量ＨＱより大きいか否かを判定する。発電負荷トルク目標値Ｔｇｔが発電機７の最大負荷容量ＨＱ以下と判定した場合には処理を終了する。一方、発電負荷トルク目標値Ｔｇｔが発電機７の最大負荷容量ＨＱよりも大きいと判定した場合には、ステップＳ１２に移行する。
【００３１】
ステップＳ１２では、発電負荷トルク目標値Ｔｇｔにおける最大負荷容量ＨＱを越える超過トルクΔＴｂを下記（７）式によって求めてからステップＳ１３に移行する。
ΔＴｂ＝Ｔｇｔ−ＨＱ …………（７）
ステップＳ１３では、スロットルセンサ２２及びエンジン回転数検出センサ２３からの信号に基づいて、図７に示すエンジントルク算出マップを参照して、現在のエンジントルクＴｅを演算してステップＳ１４に移行する。
【００３２】
ステップＳ１４では、下記（８）式のように、エンジントルクＴｅから超過トルクΔＴｂを減算してエンジントルク上限値ＴｅＭを演算し、求めたエンジントルク上限値ＴｅＭをエンジンコントローラ１９に出力した後に、ステップＳ１５に移行する。
ＴｅＭ＝Ｔｅ−ΔＴｂ …………（８）
ここで、エンジンコントローラ１９では、運転者のアクセルペダル１７の操作に関係なく、入力したエンジントルク上限値ＴｅＭをエンジントルクＴｅの上限値となるようにこのエンジントルクＴｅを制限する。
【００３３】
ステップＳ１５では、最大負荷容量ＨＱを発電負荷トルク目標値Ｔｇｔに設定してから処理を終了して余剰トルク変換部８Ｇの処理に移行する。
次に、余剰トルク変換部８Ｇの処理について、図８に基づいて説明する。
まず、ステップＳ２０で、スリップ速度ΔＶＦが“０”より大きいか否かを判定する。ΔＶＦ＞０と判定されれば、前輪１ＦＬ、１ＦＲが加速スリップしているので、ステップＳ２１に移行する。また、ΔＶＦ≦０と判定されれば、前輪１ＦＬ、１ＦＲは加速スリップしていないので、ステップＳ２１以降の余剰トルク変換処理を行うことなく処理を終了して余剰トルク演算部８Ｅの処理に戻る。
【００３４】
ステップＳ２１では、モータ用回転速度センサ３９が検出したモータ３の回転速度Ｎｍを入力し、そのモータ３の回転速度Ｎｍをもとに図８中に示すモータ界磁電流目標値算出用マップを参照してモータ界磁電流目標値Ｉｆｍｔを算出する。
ここで、目標モータ界磁電流算出用マップは、自動変速機４がドライブ（Ｄ）レンジにおける最大変速比となる第１速の変速比を基準にして作成され、横軸にモータ回転速度Ｎｍをとり、縦軸にモータ界磁電流目標値Ｉｆｍｔをとり、モータ回転速度Ｎｍが“０”から第１の設定値Ｎ_１ までの間ではモータ界磁電流目標値Ｉｆｍｔが予め設定された最大電流値Ｉ_ＭＡＸ を維持し、モータ回転速度Ｎｍが第１の設定値Ｎ_１ を超えて増加すると、これに応じてモータ界磁電流目標値Ｉｆｍｔが比較的大きな傾きで減少し、モータ回転速度Ｎｍが第１の設定値Ｎ_１ より大きな第２の設定値Ｎ_２ からこの第２の設定値Ｎ_２ より大きい第３の設定値Ｎ_３ までの間はモータ界磁電流目標値Ｉｆｍｔが初期電流値Ｉ_ＩＮより小さい低電流値Ｉ_Ｌ を維持し、モータ回転速度Ｎｍが第３の設定値Ｎ_３ を超えて増加すると、これに応じてモータ界磁電流目標値Ｉｆｍｔがより大きな傾きで減少して“０”となるように特性線Ｌ１が設定されている。
【００３５】
すなわち、回転速度Ｎｍが“０”から設定値Ｎ_１ までの間は一定の所定電流値Ｉ_ＭＡＸ とし、直流モータ３が回転速度設定値Ｎ_１ 以上になった場合には、公知の弱め界磁制御方式で直流モータ３の界磁電流Ｉｆｍを小さくする（図１０参照）。すなわち、直流モータ３が高速回転になると直流モータ３における誘起電圧の上昇によりモータトルクが低下することから、上述のように、直流モータ３の回転数Ｎｍが所定値Ｎ_１ 以上になったら直流モータ３の界磁電流Ｉｆｍを小さくして誘起電圧Ｅを低下させることで直流モータ３に流れる電流を増加させて所要モータトルクＴｍを得るようにする。この結果、直流モータ３が高速回転になってもモータ誘起電圧Ｅの上昇を抑えてモータトルクの低下を抑制するため、所要のモータトルクＴｍを得ることができる。また、モータ界磁電流Ｉｆｍを所定の回転速度未満と所定の回転速度以上との２段階で制御することで、連続的な界磁電流制御に比べ電子制御回路を安価に構成することができる。
【００３６】
次いで、ステップＳ２２に移行して、シフト位置センサ２５で検出したシフト位置を読込み、シフト位置がドライブレンジにおける第１速の変速比より小さく第２速の変速比より大きい変速比に設定されたリバース（Ｒ）レンジであるか否かを判定し、シフト位置がリバース（Ｒ）レンジ以外のレンジであるときには直接ステップＳ２４にジャンプし、シフト位置がリバース（Ｒ）レンジであるときにはステップＳ２３に移行して、下記（９）式に示すように、ステップＳ２１で算出した目標モータ界磁電流Ｉｆｍｔに“１”未満の補正係数Ｋ_Ａ （例えばＫ_Ａ ＝０．８）を乗算して新たな目標モータ界磁電流Ｉｆｍｔを算出する補正処理を行ってからステップＳ２４に移行する。
【００３７】
Ｉｆｍｔ＝Ｉｆｍｔ×Ｋ_Ａ …………（９）
ステップＳ２４では、ステップＳ２２又はステップＳ２３で算出した目標モータ界磁電流Ｉｆｍｔをモータ制御部８Ｃに出力してからステップＳ２５に移行する。
このステップＳ２５では、モータ回転速度Ｎｍと、ステップＳ２１又はステップＳ２３で算出したモータ界磁電流目標値Ｉｆｍｔとをもとに図８中に示したモータ誘起電圧算出用マップを参照してモータ誘起電圧Ｅを算出する。ここで、モータ誘起電圧算出用マップは、モータ界磁電流目標値Ｉｆｍｔをパラメータとして横軸にモータ回転速度Ｎｍをとり、縦軸にモータ誘起電圧Ｅをとり、モータ回転速度Ｎｍが増加することにより、モータ誘起電圧Ｅが線形に増加し、モータ界磁電流目標値Ｉｆｍｔが増加することによってもモータ誘起電圧Ｅが増加するように設定されている。
【００３８】
次いで、ステップＳ２６に移行して、上記余剰トルク演算部８Ｅが演算した発電負荷トルク目標値Ｔｇｔに基づき対応するモータトルク目標値Ｔｍｔを算出して、ステップＳ２７に移行する。
ステップＳ２７では、上記モータトルク目標値Ｔｍｔ及びモータ界磁電流目標値Ｉｆｍｔをもとに図９に示す電機子電流目標値算出用マップを参照して電子電流目標値Ｉａｔを算出する。この電機子電流目標値算出用マップは、モータ界磁電流目標値Ｉｆｍｔをパラメータとして、横軸にモータトルク目標値Ｔｍｔをとり、縦軸に電機子電流目標値Ｉａｔをとり、モータ出力トルクＴｍが“０”であるときにはモータ界磁電流目標値Ｉｆｍｔの値にかかわらず電機子電流目標値Ｉａｔが“０”となり、この状態からモータ出力トルクＴｍが増加するに応じて電機子電流目標値Ｉａｔが増加すると共に、モータ界磁電流目標値Ｉｆｍｔが増加するに応じて電機子電流目標値Ｉａｔが減少し、モータ出力トルクＴｍが大きな値となると、モータ界磁電流目標値Ｉｆｍｔが小さい方から順次に電機子電流目標値Ｉａｔが“０”に設定されるように構成されている。
【００３９】
次いで、ステップＳ２８に移行し、下記（９）式に基づき、電機子電流目標値Ｉａｔ、電線９の抵抗及び直流モータ３のコイルの抵抗の合成抵抗Ｒ、及び誘起電圧Ｅから発電機７の電圧目標値Ｖ_Ｇ を算出し、この発電機７の電圧目標値Ｖ_Ｇ を発電機制御部８Ａに出力した後、処理を終了して余剰トルク演算部８Ｅの処理に戻る。
【００４０】
Ｖ_Ｇ ＝Ｉａｔ×Ｒ＋Ｅ …………（９）
この図８の処理において、ステップＳ２１及びステップＳ２４の処理とモータ制御部８Ｃとが界磁電流制御手段に対応し、ステップＳ２２及びＳ２３の処理が界磁電流補正手段に対応している。
次に、上記第１の実施形態の動作を図１０に示すタイムチャートを伴って説明する。
【００４１】
今、自動変速機のセレクトレバーをパーキングレンジ（Ｐ）とし、イグニッションスイッチをオン状態とすることにより、エンジン２を始動させた状態で車両が停止しているものとする。
この停止状態で、運転者が４ＷＤスイッチ２６を図１０（ａ）に示すように時点ｔ１でオン状態に操作すると、この時点ｔ１では、図１０（ｃ）に示すようにセレクトレバーがパーキングレンジにあるため、４ＷＤリレー制御部８Ｂでは４ＷＤリレー３１をオフ状態に制御し、４ＷＤコントローラ８へのパワー系電源の入力が停止されていると共に、バッテリ３２からの発電機７のフィールドコイルＦＣ、ジャンクションボックス１０のモータリレー３６、電磁クラッチ１２のクラッチコイル１２ａへの電力供給が停止されている。
【００４２】
この停止状態から時点ｔ２でセレクトレバーをパーキング（Ｐ）レンジからリバースレンジ（Ｒ）及びニュートラル（Ｎ）レンジを経てドライブ（Ｄ）レンジに移動させ、時点ｔ３でドライブ（Ｄ）レンジを選択してから例えば０．０５秒程度の所定時間が経過した時点ｔ４で４ＷＤリレー制御部８Ｂによって４ＷＤリレー３１が図１０（ｂ）に示すようにオン状態に制御される。
【００４３】
この状態では、車両が停止状態にあるため、前輪１ＦＬ，１ＦＲの平均前輪速ＶＷｆ及び後輪１ＲＬ，１ＲＲの平均後輪速ＶＷｒが共に“０”であり、スリップ速度ΔＶＦも“０”となるため、余剰トルク変換部８Ｇで実行される図８の処理では、ステップＳ２０からステップＳ２１〜ステップＳ２５の処理を実行することなく処理を終了して余剰トルク演算部８Ｅに戻ることになる。
【００４４】
このため、発電機制御部８Ａで発電電圧目標値Ｖ_Ｇ に基づく発電機制御出力Ｃ１がオフ状態、モータ界磁出力ＭＦもオフ状態に制御され、さらにクラッチ制御部８Ｄでクラッチ制御出力ＣＬがオフ状態に制御される。したがって、発電機７での発電及び直流モータ３の駆動が停止されていると共に、クラッチ１２が非締結状態に制御される。
【００４５】
この状態から時点ｔ５でアクセルペダル１７を大きく踏込んで車両を急発進させたり、アクセルペダル１７を大きく踏込まなくても降雨路、雪路、凍結路のような低摩擦係数路面で前進方向に発進させることにより、主駆動輪となる前輪１ＦＬ，１ＦＲに加速スリップを生じると、前後の車輪速差が生じることにより、スリップ速度ΔＶＦが正の値となる。
【００４６】
このとき、クラッチ制御部８Ｄでクラッチ制御出力ＣＬが所定のデューティ比に制御されて電磁クラッチ１２が締結状態となり、これと同時に余剰トルク演算部８Ｅにおける図５の処理で、スリップ速度ΔＶＦが正値となるので、ステップＳ２からステップＳ４に移行し、スリップ速度ΔＶＦにゲインＫ１を乗算して加速スリップを抑えるために必要な吸収トルクＴΔＶＦを算出し、次いで、現在の発電電圧Ｖ_Ｇ 、電機子電流Ｉａ、発電機回転数Ｎｇに基づいて前記（５）式の演算を行って現在の発電負荷トルクＴＧを算出する（ステップＳ５）。この現在の発電負荷トルクＴＧは、図１０（ｄ）に示すように、発進時には発電機回転数Ｎｇが比較的小さいので、発電電圧Ｖ_Ｇ 及び電機子電流Ｉａの増加に応じて増加する。さらに、吸収トルクＴΔＶＦと現在の発電負荷トルクＴＧとを乗算して発電負荷トルク目標値Ｔｇｔを算出するので、この発電負荷トルク目標値Ｔｇｔも図１０（ｅ）に示すように増加する。
【００４７】
この発進時には、発電機７での発電電圧Ｖ_Ｇ が図１０（ｊ）に示すようにバッテリ電圧Ｖ_Ｂ に比較して低いので、ダイオードＤ１がオフ状態となり、ダイオードＤ２がオン状態となって、バッテリ電圧Ｖ_Ｂ が発電機７のフィールドコイルＦＣに供給される。このため、フィールドコイルＦＣに十分な界磁電流Ｉｆｇを供給することができ、発電電圧Ｖ_Ｇ の増加が可能となり、直流モータ３に供給する電機子電流Ｉａを増加させることができる。
【００４８】
ところで、発電機７で発生させる発電電圧Ｖ_Ｇ は、余剰トルク変換部８Ｇの図８の処理で制御されることになるが、モータトルク目標値Ｔｍｔとモータ界磁電流目標値Ｉｆｍｔとをもとに図９の電機子電流目標値算出用マップを参照して算出される電機子電流目標値Ｉａｔに線路抵抗Ｒを乗算した電圧値と直流モータ３での誘起電圧Ｅとを加算して算出される。
【００４９】
ここで、モータ界磁電流目標値Ｉｆｍｔは、モータ回転速度Ｎｍをもとに図８の処理におけるステップＳ２１でモータ界磁電流目標値算出用マップを参照して算出されるが、車両の発進時にはモータ回転速度Ｎｍがまだ低いため、このときのモータ界磁電流目標値Ｉｆｍｔが最大電流Ｉ_ＭＡＸ に設定される。
そして、自動変速機４のシフト位置がドライブ（Ｄ）レンジであり、車速が比較的低いので、自動変速機４が第１速のギヤ位置となるので、ステップＳ２２から直接ステップＳ２４に移行することにより、ステップＳ２１で算出されたモータ界磁電流目標値Ｉｆｍｔがそのままモータ制御部８Ｃに出力されることにより、直流モータ３が駆動開始される。
【００５０】
このとき、続くステップＳ２５で算出されるモータ誘起電圧Ｅも図１０（ｈ）に示すように増加するため、ステップＳ２７で算出される電機子電流目標値Ｉａｔが図１０（ｉ）に示すように、時間の経過と共に上昇し、必要とするモータトルクＴｍを確保することができ、直流モータ３の回転速度Ｎｍは図１０（ｆ）に示すように前輪１ＦＬ，１ＦＲの加速スリップに応じて増加する。
【００５１】
この結果、急発進時又は低摩擦係数路面での発進時に主駆動輪となる前輪１ＦＬ，１ＦＲで加速スリップを生じた場合に、これを解消するように従駆動輪となる後輪１ＲＬ，１ＲＲを直流モータ３が前輪１ＦＬ，１ＦＲでの加速スリップを解消するように駆動されることになり、円滑な発進を行うことができる。
その後、時点ｔ６で、発電電圧Ｖ_Ｇ がバッテリ電圧Ｖ_Ｂ を超えると、ダイオードＤ２がオフ状態となり、これに代えてダイオードＤ１がオン状態となることにより、バッテリ電圧Ｖ_Ｂ が発電機７のフィールドコイルＦＣに供給される他励制御状態から発電機７の整流回路３０から出力される発電電圧Ｖ_Ｇ がフィールドコイルＦＣに供給される自励制御状態に切換えられる。
【００５２】
その後、時点ｔ７で、発電負荷トルク目標値Ｔｇｔがピークに達し、その後減少することにより、電動機電流目標値Ｉａｔも徐々に減少し、これに応じて発電電圧Ｖ_Ｇ も緩やかな増加状態となる。
その後、時点ｔ８で、発電機負荷トルク目標値Ｔｇｔが比較的低い一定値を維持する状態となると、モータ回転速度Ｎｍが増加傾向を継続することからモータ誘起電圧Ｅも増加傾向を継続し、モータ界磁電流目標値Ｉｆｍｔが最大値Ｉ_ＭＡＸ を継続するので、電機子電流目標値Ｉａｔも比較的低い一定値を維持する状態となるが、発電電圧Ｖ_Ｇ はモータ誘起電圧Ｅの増加に伴って増加する。
【００５３】
その後、時点ｔ９で、モータ回転速度Ｎｍが設定回転速度Ｎ１に達すると、モータ界磁電流目標値Ｉｆｍｔが減少して界磁弱め制御が開始される。このとき、モータ回転速度Ｎｍが増加を継続しているので、モータ誘起電圧Ｅは図１０（ｈ）に示すように一定値となる。一方、電機子電流目標値Ｉａｔは、モータ界磁電流目標値Ｉｆｍｔの減少に伴って図１０（ｉ）に示すように緩やかな増加傾向となり、発電電圧Ｖ_Ｇ も図１０（ｊ）に示すように緩やかな増加状態となる。
【００５４】
その後、時点ｔ１０で、モータ回転速度Ｎｍが設定回転速度Ｎ２に達すると、モータ界磁電流目標値Ｉｆｍｔが一定値の低電流値Ｉ_Ｌ となることにより、モータ回転速度Ｎｍの増加に応じてモータ誘起電圧Ｅが図１０（ｈ）に示すように増加し、電機子電流目標値Ｉａｔは図１０（ｉ）に示すように一定値を維持し、発電電圧Ｖ_Ｇ はモータ誘起電圧Ｅの増加に応じて増加する。
【００５５】
その後、時点ｔ１１で、モータ回転速度Ｎｍが設定回転速度Ｎ３に達すると、モータ界磁電流目標値Ｉｆｍｔが図１０（ｇ）に示すように“０”となるので、モータ誘起電圧Ｅも“０”となり、電機子電流目標値Ｉａｔも“０”に近い値となり、発電電圧Ｖ_Ｇ も“０”に近い値となる。
この間にクラッチ制御部８Ｄでは、発電負荷トルク目標値Ｔｇｔに基づいて図８のステップＳ２６で算出されるモータトルク目標値Ｔｍｔが徐々に低下し、このモータトルク目標値Ｔｍｔが予め設定したクラッチ遮断閾値まで低下したときに電磁クラッチ１２に供給するクラッチ制御出力ＣＬをオフ状態として電磁クラッチ１２を締結状態から解放状態に制御して、４輪駆動状態を終了して２輪駆動状態に移行する。
【００５６】
一方、車両の停止状態で、セレクトレバーをパーキング（Ｐ）レンジからリバース（Ｒ）レンジとして、車両を後進方向に発進する場合には、基本的には上記ドライブ（Ｄ）レンジでの前進方向への発進と同様の処理が行われて、急発進や低摩擦係数路面での発進による加速スリップを解消するように電動モータ３が駆動されて、その駆動トルクによって加速スリップを解消する制御が行われる。
【００５７】
しかしながら、このリバース（Ｒ）レンジでの発進状態では、自動変速機４の変速比が前述したドライブ（Ｄ）レンジでの第２速の変速比よりは大きい値に設定されているが最大変速比となる第１速の変速比よりは小さく設定されているので、車速に対するエンジン回転速度Ｎｅは、図１１に示すように、実線図示のドライブ（Ｄ）レンジの第１速の特性線Ｌ１に対してリバース（Ｒ）レンジでは点線図示の特性線ＬＲで示すように傾きが小さくなる。
【００５８】
このため、リバース（Ｒ）レンジで後進走行する場合は、ドライブ（Ｄ）レンジの第１速で走行しているときに発電機８の発電電圧が電動モータ３の逆起電力を越える状態となって発電電流を発生させることができる発電可能状態となる車速Ｖｇに達しても、発電機８が発電状態に達しておらず、車速Ｖ１より速い車速Ｖｒとなったときに初めて発電機８が発電可能状態となり、リバース（Ｒ）レンジでの発電機８の発電量が全体的にドライブ（Ｄ）レンジの第１速の発電量に比較して少なくなっている。
【００５９】
このため、リバース（Ｒ）レンジでの後進走行状態では、ドライブ（Ｄ）レンジの第１速での前進走行状態に対して発電機８の発電量が低下することにより、特に発進状態及び車速が増加して４輪駆動状態から２輪駆動状態に移行する際に、電動モータ３に供給する電機子電流Ｉａが電機子電流目標値Ｉａｔを下回る状態となり、発電不足によって電動モータ３で発生する駆動トルクが下回って、正確な電動モータ制御を行うことができなくなる。
【００６０】
本実施形態では、リバース（Ｒ）レンジで走行する状態となると、図８の処理において、ステップＳ２２からステップＳ２３に移行して、ステップＳ２１で算出したモータ界磁電流目標値Ｉｆｍｔに対して例えば０．８に設定された補正係数Ｋ_Ａ を乗算して、ステップＳ２１で算出したモータ界磁電流目標値Ｉｆｍｔに対して減少補正したモータ界磁電流目標値Ｉｆｍｔを算出し、この減少補正したモータ界磁電流目標値Ｉｆｍｔをモータ制御部８Ｃに出力して、電動モータ３のモータ界磁電流Ｉｆｍをモータ界磁電流目標値Ｉｆｍｔに一致するように制御する。
【００６１】
このため、リバース（Ｒ）レンジでの走行状態では、図１２（ｂ）に示すように、モータ界磁電流Ｉｆｍがドライブ（Ｄ）レンジでの走行時のモータ界磁電流Ｉｆｍに対して小さい値となり、これに応じて電動モータ３で発生するモータ誘起電圧Ｅがモータ回転速度にモータ界磁電流Ｉｆｍを乗じた値に比例するので、このモータ誘起電圧Ｅが図１２（ｃ）に示すようにドライブ（Ｄ）レンジに比較して減少することになる。この結果、モータ誘起電圧Ｅの減少分に応じて発電機８で発生する発電電流が増加することになり、電動モータ３に対して電機子電流目標値Ｉａｔより大きな駆動電流を供給することができ、電動モータの電機子電流Ｉａを図１２（ｄ）に示すように電機子電流目標値Ｉａｔに正確に制御して、必要とするモータトルクＴｍを正確に発生することができる。
【００６２】
因みに、リバース（Ｒ）レンジでの後進走行時にモータ界磁電流目標値Ｉｆｍｔをドライブ（Ｄ）レンジのモータ界磁電流目標値Ｉｆｍｔに維持する場合には、図１２（ｃ）で点線図示のようにモータ誘起電圧Ｅが高い状態を維持するため、発電機７の発電能力を上回ることになる。このため、電動モータ３の電機子電流Ｉａが図１２（ｄ）で点線図示のように必要な電機子電流を流すことができず、電動モータ３で必要なモータトルクＴｍを発生することができず、加速スリップの解消に影響を与える。
【００６３】
特に、エンジン２の出力側にトルクコンバータを有する自動変速機４を連結していることから、アクセルペダル１７を解放したときに、エンジン回転数速度Ｎｅが急激に低下することになり、これに応じて発電機７の回転速度も低下することから発電不足状態を増長するが、本実施形態では、上述したように、リバース（Ｄ）レンジで、モータ界磁電流Ｉｆｍの弱め制御を行うことにより、モータ誘起電圧Ｅを減少させて、発電機７で発生する発電電流を増加させるので、エンジン回転速度Ｎｅがアイドル回転速度近傍に低下しても発電電流を確保して、電動モータ３の電機子電流Ｉａを電機子電流目標値Ｉａｔに一致させて、適正なモータトルクＴｍを発生させる正確なモータ制御を行うことができる。
【００６４】
しかも、発電機７で発電した余剰の電力によって電動モータ３を駆動して、従駆動輪である後輪１ＲＬ，１ＲＲを駆動するので、車両の加速性を向上させることができる。
このとき、主駆動輪１ＦＬ，１ＦＲの路面反力限界トルクを越えた余剰のトルクで電動モータ３を駆動するため、エネルギー効率が向上し、燃費の向上に繋がる。
【００６５】
ここで、常時、後輪１ＲＬ，１ＲＲを駆動状態とした場合には、力学的エネルギー→電気的エネルギー→力学的エネルギーと何回かエネルギー変換を行うために、変換効率分のエネルギー損失が発生することで、前輪１ＦＬ，１ＦＲだけで駆動した場合に比べて車両の加速性が低下する。このため、後輪１ＲＬ，１ＲＲの駆動は減速として抑えることが望まれる。これに対し、本実施形態では、滑り易い路面等では前輪１ＦＬ，１ＦＲにエンジン２の出力トルクＴｅの全てを伝達してもその全てが駆動力として使用されないことに鑑みて、前輪１ＦＬ，１ＦＲで有効利用できない駆動力を後輪１ＲＬ，１ＲＲに出力して加速性を向上させるものである。
【００６６】
また、上記実施形態では、変速比検出手段で検出した変速比が予め設定した設定変速比より低下するとき即ちドライブ（Ｄ）レンジに変えてリバース（Ｒ）レンジが選択されたときに、発電機が発電不足状態となると判断して、モータ界磁電流目標値Ｉｆｍｔを減少補正する界磁電流補正手段を設けたので、発電機の発電不足状態となることを正確に検出して、電力不足状態に陥ることを確実に回避することができる。
【００６７】
さらに、上記実施形態では、電動機の回転速度を検出する電動機回転速度検出手段としてのモータ用回転速度センサ３９を備え、モータ用回転速度センサ３９で検出したモータ回転速度Ｎｍに基づいてモータ界磁電流目標値を算出するように構成されているので、電動モータ３で発生する駆動トルクを正確に制御することができる。
【００６８】
さらにまた、上記実施形態では、界磁電流補正手段が、変速比が設定変速比より低下するときに、１未満の補正係数を前記界磁電流制御手段で算出した電動機界磁電流目標値に乗算するように構成されているので、電動機界磁電流目標値を確実に減少補正して、発電機の発電不足を解消することができる。
なお、上記実施形態においては、自動変速機４のシフト位置をシフト位置センサ２５で検出して、リバース（Ｒ）レンジとなったときに、変速比が低下して電力不足が発生するものと判断した場合について説明したが、これに限定されるものではなく、自動変速機４の入力側回転速度及び出力側回転速度を検出して、これらの比から変速比を検出するようにしてもよい。
【００６９】
また、上記実施形態においては、リバース（Ｒ）レンジ以外のレンジに代えてリバース（Ｒ）レンジが選択されたときに、発電不足が発生するものと判断する場合について説明したが、これに限定されるものではなく、４輪駆動状態で、ドライブ（Ｄ）レンジの第１速ギヤ位置からこれより変速比の低い第２速ギヤ位置にシフトアップしたときにも、発電不足を生じることから、第２速ギヤ位置へのシフトアップを検出して、モータ界磁電流目標値Ｉｆｍｔに上記実施形態より小さい値の補正係数Ｋ_Ａ を乗算してモータ界磁電流目標値Ｉｆｍｔを減少補正するようにしてもよい。この場合の変速比検出は、自動変速機４の入力側回転速度及び出力側回転速度を検出してその比を算出するか、又は自動変速機４を制御する変速コントローラから出力される変速指令値を検出することにより、第１速ギヤ位置であるか第２速ギヤ位置であるを検出することが好ましい。
【００７０】
さらに、上記実施形態においては、自動変速機４を適用した場合について説明した場合について説明したが、これに限定されるものではなく、ベルト式無段変速機やトロイダル型無段変速機等の無段変速機を適用するようにしてもよい。この場合には、無段変速機の変速比を無段変速機の入力側回転速度及び出力側回転速度を検出することにより検出し、最大変速比から所定変速比変化量だけ変化したときにモータ界磁電流目標値Ｉｆｍｔを減少補正するか、変速比の変化量に応じた補正係数Ｋ_Ａ を設定して減少補正するようにしてもよい。また、手動変速機であってもよい。
【００７１】
さらにまた、上記実施形態においては、電力不足状態を検出したときに、モータ界磁電流目標値Ｉｆｍｔに補正係数Ｋ_Ａ を乗じて減少補正する場合について説明したが、これに限定されるものではなく、モータ界磁電流目標値Ｉｆｍｔから所定値の補正係数を減算して新たなモータ界磁電流目標値Ｉｆｍｔを算出するようにしてもよい。
【００７２】
なおさらに、上記実施形態においては、電機子電流目標値Ｉａｔとモータ誘起電圧Ｅとに基づいて発電機７の発電電圧Ｖ_Ｇ を算出し、この発電電圧Ｖ_Ｇ に基づいて発電機７の界磁制御出力ＭＦを制御する場合について説明したが、これに限定されるものではなく、電機子電流目標値Ｉａｔと電流センサ３７で検出した直流モータ３に供給される実際の電機子電流Ｉａとの偏差ΔＩａに比例制御ゲインを乗算するか、偏差ΔＩａの積分値に積分制御ゲインを乗算して発電機界磁電流Ｉｆｇを算出し、この発電機界磁電流Ｉｆｇに応じたデューティ比を算出し、このデューティ比の制発電制御出力をパイポーラトランジスタ３３に供給するようにしてもよい。
【００７３】
また、上記実施形態においては、クラッチとして電磁クラッチ１２を適用した場合について説明したが、これに限定されるものではなく、流体圧クラッチを適用することもでき、この場合には流体圧クラッチに供給する流体圧を制御する圧力制御弁を電気的に制御することにより、クラッチ締結力を制御すればよく、その他クラッチ締結力を電気的制御が可能な任意のクラッチを適用することができる。
【００７４】
さらに、上記実施形態においては、発電機７の入力軸をベルト６を介してエンジン２に連結した場合について説明したが、これに限定されるものではなく、発電機７の入力軸をトランスファの出力側から前輪１ＦＬ，１ＦＲまでの回転部分に連結するようにしてもよく、この場合には、エンジン２のアイドリング時の負荷を減少させることができる。
【００７５】
さらにまた、上記実施形態においては、モータ回転数検出手段としてモータ回転速度センサ３９を適用し、このモータ回転速度センサ３９でモータ回転速度Ｎｍを直接検出する場合について説明したが、これに限定されるものではなく、車輪速センサ２４ＲＬ及び２４ＲＲで検出した車輪速Ｖｗ_ＲＬ及びＶｗ_ＲＲとディファレンシャルギヤ１３の減速比とに基づいてモータ回転速度を推定するようにしてもよい。
【００７６】
なおさらに、上記実施形態においては、前輪１ＦＬ，１ＦＲを主駆動輪とし、後輪１ＲＬ，１ＲＲを従駆動輪とする４輪駆動車に本発明を適用した場合について説明したが、これに限定されるものではなく、後輪１ＲＬ，１ＲＲを主駆動輪とし、前輪１ＦＬ，１ＦＲを従駆動輪とするようにしてもよい。
また、上記実施形態においては、本発明を４輪駆動車に適用した場合について説明したが、これに限定されるものではなく、前後方向に２輪以上の駆動輪を備え、一部の主駆動輪を内燃機関で駆動し、残りの従駆動輪を電動機で駆動する場合に本発明を適用することができ、その他内燃機関等の回転駆動源によって回転駆動される発電機によって車輪を駆動する電動機を駆動する電動式駆動装置に本発明を適用することができる。
【図面の簡単な説明】
【図１】本発明の第１実施形態を示す概略装置構成図である。
【図２】第１実施形態における制御系のブロック図である。
【図３】第１実施形態に係る４ＷＤコントローラを示す機能ブロック図である。
【図４】第１の実施形態における４ＷＤコントローラでの制御処理手順を示すフローチャートである。
【図５】第１の実施形態における余剰トルク演算部の処理手順の一例を示すフローチャートである。
【図６】第１の実施形態における目標トルク制御部の処理手順の一例を示すフローチャートである。
【図７】エンジン回転速度Ｎｅをパラメータとしてスロットル開度θとエンジントルクＴｅとの関係を示すエンジントルク算出マップを示す図である。
【図８】第１の実施形態における余剰トルク変換部の処理手順の一例を示すフローチャートである。
【図９】モータ界磁電流目標値をパラメータとしてモータトルク目標値と電機子電流目標値との関係を示す電機子電流目標値算出マップを示す図である。
【図１０】実施形態の動作の説明に供するタイムチャートである。
【図１１】ドライブレンジの１速ギヤ位置とリバースレンジをパラメータとして車速とエンジン回転速度との関係を示す特性線図である。
【図１２】実施形態のドライブレンジとリバースレンジとの動作を比較するタイムチャートである。
【図１３】発電能力線とモータ逆起電力との関係を示す特性線図である。
【符号の説明】
１ＦＬ，１ＦＲ 前輪
１ＲＬ，１ＲＲ 後輪
２ エンジン
３ 直流モータ
４ 自動変速機
７ 発電機
８ ４ＷＤコントローラ
１０ ジャンクションボックス
１１ 減速機
１２ 電磁クラッチ
２３ エンジン回転速度センサ
２４ＦＬ〜２４ＲＲ 車輪速センサ
２５ シフト位置センサ
ＦＣ フィールドコイル
ＳＣ ステータコイル
３７ 電流センサ
３９ モータ用回転速度センサ[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a driving force control device for a vehicle that drives an electric motor that transmits driving torque to driven wheels with electric power generated by a generator.
[0002]
[Prior art]
As a driving force control device for this type of vehicle, one of the front wheels and the rear wheels is driven as a main drive wheel through the power of the internal combustion engine, and the other of the front wheels and the rear wheels is driven by an electric motor. The generator is driven by the driving force of the internal combustion engine, and the electric power generated by this generator is supplied to the motor. When the accelerator pedal is depressed and the vehicle speed is lower than the set value, the motor is operated to A front-rear wheel drive vehicle that drives wheels has been proposed (see, for example, Patent Document 1).
[0003]
[Patent Document 1]
Japanese Utility Model Publication No. 55-138129 (first page, FIG. 2)
[0004]
[Problems to be solved by the invention]
However, in Patent Document 1, since the electric motor is driven by the electric power generated by the generator driven by the internal combustion engine, the electric motor is required if the generator does not overcome the counter electromotive force of the electric motor. Can't pass current to That is, as shown in FIG. 13, when the vehicle speed is taken on the horizontal axis and the voltage is taken on the vertical axis, the power generation capacity line of the generator is “0” when the vehicle speed is “0” as shown by the solid line. When the vehicle speed increases, the rate of increase is small when the vehicle speed is low, and then the rate of increase increases as the vehicle speed increases.On the other hand, the counter electromotive force of the motor is It is represented by a straight line that is “0” when it is “0” and then increases at a constant increase rate as the vehicle speed increases. For this reason, when the vehicle speed is between “0” and the predetermined vehicle speed Vs, the power generation capacity line of the generator is lower than the counter electromotive force of the motor, so that the generated current from the generator cannot flow and the motor Although the drive torque cannot be generated, if the vehicle speed increases beyond the predetermined vehicle speed Vs, the generated current of the generator increases accordingly, and the drive torque can be generated by the electric motor.
[0005]
By the way, a transmission (transmission) is disposed on the output side of the internal combustion engine, and the rotational speed of the internal combustion engine varies depending on the transmission gear ratio when the vehicle speed is constant, and is driven by this internal combustion engine. The amount of power generated by the generator changes according to the rotational speed of the internal combustion engine. Therefore, when the power generation amount of the generator is set at, for example, the maximum gear ratio used in the low vehicle speed range of the transmission, it is input to the generator when the transmission is selected to be smaller than the maximum gear ratio. As a result, the rotational speed of the motor decreases and power generation becomes insufficient, and there is an unsolved problem that the required driving torque cannot be generated by the electric motor.
[0006]
In particular, when an automatic transmission is applied as a transmission, since it has a torque converter, when the accelerator is not depressed, the engine speed decreases and the power generation shortage tendency is further increased.
Therefore, the present invention has been made paying attention to the unsolved problems of the conventional example, and a vehicle capable of generating a necessary driving torque with an electric motor even when a power generation insufficient state occurs with the generator. An object of the present invention is to provide a driving force control apparatus.
[0007]
[Means for Solving the Problems]
To achieve the above object, a driving force control apparatus for a vehicle according to the present invention includes a main drive source for driving main drive wheels via a transmission, a generator driven by the main drive source, and the power generation In a vehicle driving force control device equipped with an electric motor driven by the electric power of the machine and capable of transmitting a driving torque to the driven wheels, the field current of the electric motor is controlled by field current control means, and the transmission The gear ratio is detected by the gear ratio detecting means,thisWhen it is determined that the generator is in an insufficient power generation state based on the speed ratio detected by the speed ratio detecting means, the field current control means controls the field current controlled by the field current control means.The back electromotive force generated in the motor is reduced.Decrease correction.
[0008]
【The invention's effect】
According to the present invention, in the four-wheel drive state in which the driven wheel is driven by the electric motor, the field current of the electric motor is determined when it is determined that the generator is in a state of insufficient power generation based on the transmission gear ratio. TheTo reduce the back electromotive force generated by the motorBecause the correction is reduced, DepartureThe effect of eliminating the power generation shortage of the electric machine and generating the required drive torque with certainty is obtained.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Next, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic configuration diagram showing an embodiment in which the present invention is applied to a four-wheel drive vehicle. Left and right front wheels 1FL and 1FR as main drive wheels are driven by an engine 2 which is an internal combustion engine, and driven wheels are driven. The left and right rear wheels 1RL and 1RR are driven by a DC motor 3 which is an electric motor.
[0010]
The output torque Te of the engine 2 is transmitted to the left and right front wheels 1FL and 1FR via an automatic transmission 4 having a torque converter and a differential gear 5. A part of the output torque Te of the engine 2 is transmitted to the generator 7 through the endless belt 6.
The generator 7 rotates at a rotational speed Ng obtained by multiplying the rotational speed Ne of the engine 2 by the pulley ratio, and becomes a load on the engine 2 according to the field current Ifg adjusted by the 4WD controller 8. Generate electricity according to The electric power generated by the generator 7 is supplied to the DC motor 3 through the electric wire 9 and the junction box 10. The output shaft of the DC motor 3 is connected to a reduction gear 11, an electromagnetic clutch 12 as a clutch, and a differential gear 13, and the left and right output sides of the differential gear 13 are connected to left and right rear wheels 1RL and 1RR via drive shafts 13L and 13R, respectively. Has been.
[0011]
A main throttle valve 15 and a sub-throttle valve 16 are interposed in the intake pipe line 14 (for example, an intake manifold) of the engine 2. The throttle opening of the main throttle valve 15 is adjusted and controlled according to the depression amount of the accelerator pedal 17 and the like. The main throttle valve 15 is mechanically linked to the depression amount of the accelerator pedal 17, or the engine controller 19 is electrically operated according to the depression amount detection value of the accelerator sensor 18 that detects the depression amount of the accelerator pedal 17. By performing adjustment control, the throttle opening is adjusted. The detected amount of depression of the accelerator sensor 18 is also output to the 4WD controller 8.
[0012]
The sub-throttle valve 16 is adjusted and controlled by a rotation angle corresponding to the number of steps using the step motor 20 as an actuator. The rotation angle of the step motor 20 is adjusted and controlled by a drive signal from the motor controller 21. The sub-throttle valve 16 is provided with a throttle sensor 22, and the number of steps of the step motor 20 is feedback-controlled based on a throttle opening detection value detected by the throttle sensor 22. Here, by adjusting the throttle opening degree of the sub throttle valve 16 to be equal to or less than the opening degree of the main throttle valve 15, the output torque of the engine 2 is reduced independently of the driver's operation of the accelerator pedal. Can do.
[0013]
The engine 2 is provided with an engine rotation speed sensor 23 for detecting the output rotation speed Ne, and the engine rotation speed Ne detected by the engine rotation speed sensor 23 is output to the 4WD controller 8. Further, each of the wheels 1FL to 1RR is provided with a wheel speed sensor 24FL to 24RR for detecting the wheel speed, and the wheel speed Vw detected by the wheel speed sensors 24FL to 24RR is provided._FL~ Vw_RRIs output to the 4WD controller 8. Furthermore, a shift position sensor 25 is provided as a gear ratio detecting means for detecting the shift position of the automatic transmission 4, and the shift position detected by the shift position sensor 25 is input to the 4WD controller 8. Furthermore, a 4WD switch 26 is provided in the vicinity of the driver's seat to select whether or not to set the four-wheel drive state, and a switch signal of the 4WD switch 26 is input to the 4WD controller 8.
[0014]
Further, as shown in FIG. 2, the generator 7 includes a delta-connected three-phase stator coil SC and a field coil FC, and a rectifier circuit 30 in which each connection point of the stator coil SC is configured by a diode. The rectifier circuit 30 is connected to the DC voltage V of, for example, 42V at the maximum._GIs output.
Further, one end of the field coil FC is connected to the output side of the rectifier circuit 30 via the diode D1, and the diode D2 is connected in the reverse direction, and a predetermined voltage (for example, 12 volts) is further passed through the 4WD relay 31. The other end is connected to the cathode side of the diodes D1 and D2 via the flywheel diode DF in the forward direction, and is grounded via a bipolar transistor 33 constituting a voltage regulator (regulator). Has been.
[0015]
Here, a system that supplies the field current Ifg via the rectifier circuit 30 and the diode D1 forms a self-excited circuit, and a system that supplies the field current Ifg via the battery 31 and the diode D2 forms a separately excited circuit. The diodes D1 and D2 have a select high function for selecting the higher one of the voltages of the self-excited circuit and the separately-excited circuit.
In addition, one end of the relay coil of the 4WD relay 31 is connected to the output side of the ignition relay 35 connected to the battery 32 via the ignition switch 34, and the other end is connected to the 4WD controller 8.
[0016]
The generator 7 adjusts the field current Ifg for the field coil FC by the 4WD controller 8, thereby generating the power generation load torque Tg for the engine 2 and the power generation voltage V to be generated._GIs controlled. The bipolar transistor 33 receives a generator control command (field current value) C1 subjected to pulse width modulation (PWM) from the 4WD controller 8 and sets the field current Ifg of the generator 7 to a value corresponding to the generator control command C1. Adjust.
[0017]
In addition, a motor relay 36 and a current sensor 37 are connected in series in the junction box 10, and the motor relay 36 interrupts power supplied to the DC motor 3 in response to a command from the 4WD controller 8. The current sensor 37 detects the armature current Ia supplied from the generator 7 to the DC motor 3 and outputs the detected armature current Ia to the 4WD controller 8. The motor voltage Vm supplied to the DC motor 3 is detected by the 4WD controller 8.
[0018]
Further, in DC motor 3, field current Ifm is controlled by a pulse width modulated field control command as a motor output torque command from 4WD controller 8, and drive torque Tm is adjusted by adjusting field current Ifm. The temperature of the DC motor 3 is detected by the thermistor 38, and the detected temperature value is input to the 4WD controller 8, and the rotational speed Nm of the output shaft of the DC motor 3 is a motor rotational speed sensor as a motor rotational speed detecting means. 39, and the rotational speed Nm is input to the 4WD controller 8.
[0019]
The electromagnetic clutch 12 has one end of the exciting coil 12a connected to the output side of the 4WD relay 21 and the other end connected to the 4WD controller 8. The 4WD controller 8 includes a switching transistor 40 as a switching element. Is grounded. The energizing current of the exciting coil 12a is controlled by the clutch control command CL which is pulse-width modulated supplied to the base of the transistor 40, and thereby the torque transmitted from the DC motor 3 to the rear wheels 1RL and 1RR as the driven wheels. The transmission force is controlled.
[0020]
As shown in FIG. 3, the 4WD controller 8 includes a generator control unit 8A, a relay control unit 8B, a motor control unit 8C, a clutch control unit 8D, a surplus torque calculation unit 8E, a target torque limiting unit 8F, and a surplus torque conversion unit 8G. It has.
The generator control unit 8A adjusts the field current Ifg of the generator 7 while monitoring the generated voltage V of the generator 7 through the bipolar transistor 33, thereby generating the generated voltage V of the generator 7._GTo the required voltage.
[0021]
The relay control unit 8 </ b> B controls cutoff / connection of power supply from the generator 7 to the DC motor 3.
The motor control unit 8C adjusts the field current Ifm of the DC motor 3 on the basis of a target motor field current Ifmt calculated by a surplus torque conversion unit 8G described later, whereby the torque of the DC motor 3 is set to a predetermined value. Adjust to.
[0022]
The clutch control unit 8D calculates the corresponding motor torque target value Tmt based on the power generation load torque target value Tgt calculated by the surplus torque calculation unit 8E described later, and calculates the following formula based on the motor torque target value Tmt. The clutch transmission torque T to the electromagnetic clutch 12_CLAnd this clutch transmission torque T_CLClutch current command value I_CLTo the clutch current command value I by pulse width modulation (PWM)_CLA clutch current control output CL having a duty ratio according to the above is obtained and output to the switching transistor 40.
[0023]
T_CL= Tmt × K_DEF× K_TM+ T_CL0
Where K_DEFIs the reduction ratio in the differential gear 13, K_TM    Is the clutch torque margin, T_CL0Is the clutch initial torque.
Further, as shown in FIG. 4, processing is performed in a cycle of surplus torque calculation unit 8 </ b> E → target torque limiting unit 8 </ b> F → surplus torque conversion unit 8 </ b> G for each predetermined sampling time based on each input signal.
[0024]
First, the surplus torque calculation unit 8E performs processing as shown in FIG.
That is, first, in step S1, based on the signals from the wheel speed sensors 16FL, 16FR, 16RL, 16RR, the average of the front wheels (main drive wheels) 1FL, 1FR to the average of the rear wheels 1RL, 1RR (slave drive wheels). By subtracting the wheel speed, a slip speed ΔVF which is an acceleration slip amount of the front wheels 1FL and 1FR is obtained.
[0025]
Here, the calculation of the slip speed ΔVF is performed as follows, for example.
The average front wheel speed VWf, which is the average value of the left and right wheel speeds of the front wheels 1FL, 1FR, and the average rear wheel speed VWr, which is the average value of the left and right wheel speeds of the rear wheels 1RL, 1RR, are calculated by the following equations.
VWf = (VW_FL+ VW_FR) / 2 ......... (1)
VWr = (VW_RL+ VW_RR) / 2 ......... (2)
Next, from the deviation between the average front wheel speed VWf and the average rear wheel speed VWr, the slip speed (acceleration slip amount) ΔVF of the front wheels 1L and 1R as the main drive wheels is calculated by the following equation (3).
[0026]
ΔVF = VWf−VWr (3)
Next, the process proceeds to step S2, and it is determined whether or not the slip speed ΔVF obtained in step S1 is a positive value greater than a predetermined value, for example, “0”. When the determination result indicates that the slip speed ΔVF is equal to or less than “0”, that is, “0” or a negative value, it is estimated that the front wheels 1FL, 1FR are not slipping at acceleration, so the routine proceeds to step S3 and the generated load torque target After the value Tgt is set to “0”, the post-processing is terminated, and the process proceeds to the processing of the target torque limiting unit 8F.
[0027]
On the other hand, when the slip speed ΔVF is a positive value larger than “0” in step S2, it is estimated that the front wheels 1FL and 1FR are slipping at an acceleration, and therefore the process proceeds to step S4.
In this step S4, the absorption torque TΔVF necessary for suppressing the acceleration slip of the front wheels 1FL, 1FR is calculated by the following equation (4), and then the process proceeds to step S5. The absorption torque TΔVF is an amount proportional to the acceleration slip amount.
[0028]
TΔVF = K1 × ΔVF (4)
Here, K1 is a gain obtained through experiments or the like.
In step S5, the current load torque TG of the generator 7 is calculated based on the following equation (5), and then the process proceeds to step S6.

Here, Vg is the voltage of the generator 7, Ia is the armature current of the generator 7, Ng is the rotational speed of the generator 7, K2 is a coefficient, and K3 is efficiency.
[0029]
In step S6, after determining the surplus torque, that is, the power generation load torque target value Tgt to be loaded by the generator 7, based on the following equation (6), the process is terminated and the process proceeds to the process of the target torque limiting unit 8F.
Tgt = TG + TΔVF (6)
Next, the processing of the target torque limiting unit 8F will be described based on FIG.
[0030]
That is, first, in step S11, it is determined whether the power generation load torque target value Tgt is greater than the maximum load capacity HQ of the generator 7. When it is determined that the power generation load torque target value Tgt is equal to or less than the maximum load capacity HQ of the generator 7, the process is terminated. On the other hand, when it determines with the electric power generation load torque target value Tgt being larger than the maximum load capacity HQ of the generator 7, it transfers to step S12.
[0031]
In step S12, the excess torque ΔTb exceeding the maximum load capacity HQ at the power generation load torque target value Tgt is obtained by the following equation (7), and then the process proceeds to step S13.
ΔTb = Tgt−HQ (7)
In step S13, the current engine torque Te is calculated based on the signals from the throttle sensor 22 and the engine speed detection sensor 23 with reference to the engine torque calculation map shown in FIG. 7, and the process proceeds to step S14.
[0032]
In step S14, as shown in the following equation (8), the engine torque upper limit TeM is calculated by subtracting the excess torque ΔTb from the engine torque Te, and the calculated engine torque upper limit TeM is output to the engine controller 19; The process proceeds to S15.
TeM = Te−ΔTb (8)
Here, the engine controller 19 limits the engine torque Te so that the input engine torque upper limit value TeM becomes the upper limit value of the engine torque Te regardless of the driver's operation of the accelerator pedal 17.
[0033]
In step S15, after setting the maximum load capacity HQ to the power generation load torque target value Tgt, the process is terminated and the process proceeds to the process of the surplus torque converter 8G.
Next, the process of the surplus torque converter 8G will be described with reference to FIG.
First, in step S20, it is determined whether or not the slip speed ΔVF is greater than “0”. If it is determined that ΔVF> 0, the front wheels 1FL and 1FR are accelerating and slipping, and the process proceeds to step S21. If it is determined that ΔVF ≦ 0, the front wheels 1FL and 1FR have not accelerated slip, so the process is terminated without performing the surplus torque conversion process after step S21, and the process returns to the surplus torque calculation unit 8E.
[0034]
In step S21, the rotational speed Nm of the motor 3 detected by the motor rotational speed sensor 39 is input, and the motor field current target value calculation map shown in FIG. 8 is referred to based on the rotational speed Nm of the motor 3. Then, the motor field current target value Ifmt is calculated.
Here, the target motor field current calculation map is created based on the speed ratio of the first speed, which is the maximum speed ratio in the drive (D) range of the automatic transmission 4, and the motor rotation speed Nm is plotted on the horizontal axis. The motor field current target value Ifmt is taken on the vertical axis, and the motor rotation speed Nm is changed from “0” to the first set value N.₁Until the motor field current target value Ifmt is set to a preset maximum current value I_MAXAnd the motor rotation speed Nm is the first set value N₁If the motor field current target value Ifmt decreases with a relatively large slope, the motor rotation speed Nm decreases to the first set value N.₁Larger second set value N₂To this second set value N₂Third set value N greater than₃Until the motor field current target value Ifmt is the initial current value I_INSmaller current value I_LAnd the motor rotation speed Nm is the third set value N₃The characteristic line L1 is set so that the motor field current target value Ifmt decreases to a value of “0” with a larger slope in response to the increase.
[0035]
That is, the rotational speed Nm is changed from “0” to the set value N₁Until a certain predetermined current value I_MAXDC motor 3 is set to rotation speed set value N₁In the case described above, the field current Ifm of the DC motor 3 is reduced by a known field weakening control method (see FIG. 10). That is, when the DC motor 3 rotates at a high speed, the motor torque decreases due to an increase in the induced voltage in the DC motor 3, so that the rotational speed Nm of the DC motor 3 is a predetermined value N as described above.₁When the above is reached, the field current Ifm of the DC motor 3 is reduced to reduce the induced voltage E, thereby increasing the current flowing through the DC motor 3 to obtain the required motor torque Tm. As a result, even if the DC motor 3 rotates at a high speed, the required motor torque Tm can be obtained because the increase in the motor induced voltage E is suppressed and the decrease in the motor torque is suppressed. In addition, by controlling the motor field current Ifm in two stages of less than a predetermined rotation speed and more than a predetermined rotation speed, the electronic control circuit can be configured at a lower cost than continuous field current control.
[0036]
Next, the process proceeds to step S22, where the shift position detected by the shift position sensor 25 is read, and the shift position is set to a gear ratio that is smaller than the gear ratio of the first speed in the drive range and larger than the gear ratio of the second speed. It is determined whether or not it is in the (R) range. If the shift position is in a range other than the reverse (R) range, the process jumps directly to step S24, and if the shift position is in the reverse (R) range, the process proceeds to step S23. As shown in the following equation (9), the correction coefficient K of less than “1” is added to the target motor field current Ifmt calculated in step S21._A(For example, K_A= 0.8), and a correction process for calculating a new target motor field current Ifmt is performed, and then the process proceeds to step S24.
[0037]
Ifmt = Ifmt × K_A    ............ (9)
In step S24, the target motor field current Ifmt calculated in step S22 or step S23 is output to the motor control unit 8C, and then the process proceeds to step S25.
In this step S25, the motor induced voltage is determined by referring to the motor induced voltage calculation map shown in FIG. 8 based on the motor rotation speed Nm and the motor field current target value Ifmt calculated in step S21 or S23. E is calculated. Here, the motor induced voltage calculation map uses the motor field current target value Ifmt as a parameter, the horizontal axis represents the motor rotation speed Nm, the vertical axis represents the motor induced voltage E, and the motor rotation speed Nm increases. The motor induced voltage E is set to increase linearly as the motor induced voltage E increases linearly and the motor field current target value Ifmt increases.
[0038]
Next, the process proceeds to step S26, a corresponding motor torque target value Tmt is calculated based on the power generation load torque target value Tgt calculated by the surplus torque calculation unit 8E, and the process proceeds to step S27.
In step S27, the electronic current target value Iat is calculated with reference to the armature current target value calculation map shown in FIG. 9 based on the motor torque target value Tmt and the motor field current target value Ifmt. This armature current target value calculation map uses the motor field current target value Ifmt as a parameter, the horizontal axis represents the motor torque target value Tmt, the vertical axis represents the armature current target value Iat, and the motor output torque Tm is When it is “0”, the armature current target value Iat becomes “0” regardless of the value of the motor field current target value Ifmt, and as the motor output torque Tm increases from this state, the armature current target value Iat becomes smaller. As the motor field current target value Ifmt increases, the armature current target value Iat decreases, and when the motor output torque Tm becomes a large value, the motor field current target value Ifmt decreases from the smaller one. The armature current target value Iat is configured to be set to “0”.
[0039]
Next, the process proceeds to step S28, and the voltage of the generator 7 is calculated from the armature current target value Iat, the combined resistance R of the resistance of the electric wire 9 and the resistance of the coil of the DC motor 3, and the induced voltage E based on the following equation (9). Target value V_GAnd the voltage target value V of this generator 7_GIs output to the generator control unit 8A, the process is terminated, and the process returns to the surplus torque calculation unit 8E.
[0040]
V_G= Iat x R + E (9)
In the process of FIG. 8, the processes of steps S21 and S24 and the motor controller 8C correspond to the field current control means, and the processes of steps S22 and S23 correspond to the field current correction means.
Next, the operation of the first embodiment will be described with reference to the time chart shown in FIG.
[0041]
Now, it is assumed that the vehicle is stopped with the engine 2 started by setting the select lever of the automatic transmission to the parking range (P) and turning on the ignition switch.
In this stop state, when the driver operates the 4WD switch 26 to the on state at time t1 as shown in FIG. 10A, at this time t1, the select lever is moved to the parking range as shown in FIG. 10C. Therefore, the 4WD relay control unit 8B controls the 4WD relay 31 to be in an OFF state, the input of the power system power supply to the 4WD controller 8 is stopped, the field coil FC of the generator 7 from the battery 32, and the junction box. The power supply to the motor relay 36 and the clutch coil 12a of the electromagnetic clutch 12 is stopped.
[0042]
From this stop state, at time t2, the select lever is moved from the parking (P) range to the drive (D) range via the reverse range (R) and neutral (N) range, and at time t3, the drive (D) range is selected. For example, the 4WD relay control unit 8B controls the 4WD relay 31 to the on state as shown in FIG. 10B at a time point t4 when a predetermined time of about 0.05 seconds elapses.
[0043]
In this state, since the vehicle is stopped, the average front wheel speed VWf of the front wheels 1FL and 1FR and the average rear wheel speed VWr of the rear wheels 1RL and 1RR are both “0”, and the slip speed ΔVF is also “0”. Therefore, in the process of FIG. 8 executed by the surplus torque conversion unit 8G, the process ends without returning to the surplus torque calculation unit 8E without executing the processes from step S20 to step S21 to step S25.
[0044]
Therefore, the generator control unit 8A generates the generated voltage target value V_G, The generator control output C1 is controlled to be off, the motor field output MF is also controlled to be off, and the clutch control output CL is controlled to be off by the clutch control unit 8D. Accordingly, power generation by the generator 7 and driving of the DC motor 3 are stopped, and the clutch 12 is controlled to be in a non-engaged state.
[0045]
From this state, at time t5, the accelerator pedal 17 is greatly depressed to start the vehicle suddenly, or even if the accelerator pedal 17 is not largely depressed, the vehicle starts in a forward direction on a road surface with a low friction coefficient such as a rainy road, a snowy road, and a freezing road. As a result, when an acceleration slip occurs in the front wheels 1FL and 1FR serving as the main drive wheels, a difference between the front and rear wheel speeds occurs, and the slip speed ΔVF becomes a positive value.
[0046]
At this time, the clutch control output CL is controlled to a predetermined duty ratio by the clutch control unit 8D, and the electromagnetic clutch 12 is engaged. At the same time, the slip speed ΔVF is a positive value in the process of the surplus torque calculation unit 8E in FIG. Therefore, the process proceeds from step S2 to step S4, and the absorption torque TΔVF required to suppress the acceleration slip is calculated by multiplying the slip speed ΔVF by the gain K1, and then the current generated voltage V_GBased on the armature current Ia and the generator rotational speed Ng, the calculation of the equation (5) is performed to calculate the current power generation load torque TG (step S5). As shown in FIG. 10 (d), the current power generation load torque TG has a relatively small generator rotational speed Ng at the time of starting, so that the power generation voltage V_GAnd it increases as the armature current Ia increases. Furthermore, since the power generation load torque target value Tgt is calculated by multiplying the absorption torque TΔVF by the current power generation load torque TG, the power generation load torque target value Tgt also increases as shown in FIG.
[0047]
At the time of this start, the generated voltage V at the generator 7_GAs shown in FIG. 10 (j), the battery voltage V_B, The diode D1 is turned off, the diode D2 is turned on, and the battery voltage V_BIs supplied to the field coil FC of the generator 7. Therefore, a sufficient field current Ifg can be supplied to the field coil FC, and the generated voltage V_GThe armature current Ia supplied to the DC motor 3 can be increased.
[0048]
By the way, the generated voltage V generated by the generator 7_GIs controlled by the process of FIG. 8 of the surplus torque conversion unit 8G. Based on the motor torque target value Tmt and the motor field current target value Ifmt, the armature current target value calculation map of FIG. Is calculated by adding the voltage value obtained by multiplying the armature current target value Iat calculated by reference to the line resistance R and the induced voltage E in the DC motor 3.
[0049]
Here, the motor field current target value Ifmt is calculated with reference to the motor field current target value calculation map in step S21 in the process of FIG. 8 based on the motor rotational speed Nm. Since the motor rotation speed Nm is still low, the motor field current target value Ifmt at this time is the maximum current I_MAXSet to
Since the shift position of the automatic transmission 4 is in the drive (D) range and the vehicle speed is relatively low, the automatic transmission 4 is in the first gear position, so that the process proceeds directly from step S22 to step S24. Thus, the motor field current target value Ifmt calculated in step S21 is output to the motor control unit 8C as it is, so that the DC motor 3 is started to drive.
[0050]
At this time, since the motor induced voltage E calculated in the subsequent step S25 also increases as shown in FIG. 10 (h), the armature current target value Iat calculated in step S27 is as shown in FIG. 10 (i). As the time elapses, the required motor torque Tm can be secured, and the rotational speed Nm of the DC motor 3 increases according to the acceleration slip of the front wheels 1FL and 1FR as shown in FIG. .
[0051]
As a result, when an acceleration slip occurs on the front wheels 1FL, 1FR that are the main drive wheels at the time of sudden start or at the start on the road surface with a low friction coefficient, the rear wheels 1RL, 1RR that are the sub drive wheels are removed to eliminate this. The DC motor 3 is driven so as to eliminate the acceleration slip at the front wheels 1FL and 1FR, and a smooth start can be performed.
Thereafter, at time t6, the generated voltage V_GIs the battery voltage V_BExceeds the battery voltage V, the diode D2 is turned off, and the diode D1 is turned on instead._BIs output from the rectifier circuit 30 of the generator 7 from the separately excited control state in which is supplied to the field coil FC of the generator 7_GIs switched to the self-excited control state supplied to the field coil FC.
[0052]
Thereafter, at time t7, the power generation load torque target value Tgt reaches a peak, and then decreases, so that the motor current target value Iat also gradually decreases, and the generated voltage V_GWill gradually increase.
Thereafter, when the generator load torque target value Tgt is maintained at a relatively low constant value at time t8, the motor rotation speed Nm continues to increase, so the motor induced voltage E also continues to increase. The field current target value Ifmt is the maximum value I._MAXTherefore, the armature current target value Iat also maintains a relatively low constant value, but the generated voltage V_GIncreases as the motor-induced voltage E increases.
[0053]
Thereafter, when the motor rotation speed Nm reaches the set rotation speed N1 at time t9, the motor field current target value Ifmt decreases and the field weakening control is started. At this time, since the motor rotation speed Nm continues to increase, the motor induced voltage E becomes a constant value as shown in FIG. On the other hand, the armature current target value Iat tends to increase slowly as the motor field current target value Ifmt decreases as shown in FIG._GAs shown in FIG. 10 (j), the state gradually increases.
[0054]
Thereafter, when the motor rotation speed Nm reaches the set rotation speed N2 at time t10, the motor field current target value Ifmt is a low current value I having a constant value._LAs a result, the motor induced voltage E increases as shown in FIG. 10 (h) as the motor rotational speed Nm increases, and the armature current target value Iat becomes a constant value as shown in FIG. 10 (i). Maintain the generated voltage V_GIncreases as the motor-induced voltage E increases.
[0055]
Thereafter, when the motor rotation speed Nm reaches the set rotation speed N3 at time t11, the motor field current target value Ifmt becomes “0” as shown in FIG. The armature current target value Iat is also close to “0”, and the generated voltage V_GIs also close to “0”.
During this time, the clutch control unit 8D gradually decreases the motor torque target value Tmt calculated in step S26 of FIG. 8 based on the power generation load torque target value Tgt, and this motor torque target value Tmt is set to a preset clutch disengagement threshold value. The clutch control output CL supplied to the electromagnetic clutch 12 is turned off when the electromagnetic clutch 12 is lowered, and the electromagnetic clutch 12 is controlled from the engaged state to the released state.
[0056]
On the other hand, when the vehicle is stopped and the select lever is changed from the parking (P) range to the reverse (R) range and the vehicle is started in the reverse direction, the vehicle is basically moved forward in the drive (D) range. The electric motor 3 is driven so as to eliminate the acceleration slip due to the sudden start or the start on the low friction coefficient road surface, and the control to eliminate the acceleration slip by the driving torque is performed. .
[0057]
However, in the start state in the reverse (R) range, the speed ratio of the automatic transmission 4 is set to a value larger than the speed ratio of the second speed in the drive (D) range described above, but the maximum speed ratio. Therefore, the engine rotational speed Ne with respect to the vehicle speed is set to a characteristic line L1 of the first speed in the drive (D) range shown by the solid line, as shown in FIG. In the reverse (R) range, the slope becomes smaller as shown by the characteristic line LR shown by the dotted line.
[0058]
For this reason, when traveling backward in the reverse (R) range, the generated voltage of the generator 8 exceeds the counter electromotive force of the electric motor 3 when traveling at the first speed in the drive (D) range. Even when the vehicle speed Vg at which power generation is possible and the power generation possible state is reached, the generator 8 does not reach the power generation state and the generator 8 generates power only when the vehicle speed Vr becomes higher than the vehicle speed V1. The power generation amount of the generator 8 in the reverse (R) range is reduced as a whole compared to the power generation amount of the first speed in the drive (D) range.
[0059]
For this reason, in the reverse travel state in the reverse (R) range, the power generation amount of the generator 8 is reduced with respect to the forward travel state in the first speed of the drive (D) range. When increasing and shifting from the four-wheel drive state to the two-wheel drive state, the armature current Ia supplied to the electric motor 3 becomes lower than the armature current target value Iat, and the drive generated by the electric motor 3 due to insufficient power generation The torque falls below and accurate electric motor control cannot be performed.
[0060]
In the present embodiment, when the vehicle travels in the reverse (R) range, in the process of FIG. 8, the process proceeds from step S22 to step S23, and the motor field current target value Ifmt calculated in step S21 is, for example, 0. Correction factor K set to .8_AIs multiplied by the motor field current target value Ifmt calculated in step S21 to reduce the motor field current target value Ifmt, and the motor controller 8C calculates the motor field current target value Ifmt corrected for decrease. And the motor field current Ifm of the electric motor 3 is controlled to coincide with the motor field current target value Ifmt.
[0061]
For this reason, in the traveling state in the reverse (R) range, as shown in FIG. 12B, the motor field current Ifm is smaller than the motor field current Ifm during traveling in the drive (D) range. Accordingly, since the motor induced voltage E generated in the electric motor 3 is proportional to the value obtained by multiplying the motor rotation speed by the motor field current Ifm, the motor induced voltage E is as shown in FIG. It will decrease compared to the drive (D) range. As a result, the generated current generated by the generator 8 increases in accordance with the decrease in the motor induced voltage E, and a drive current larger than the armature current target value Iat can be supplied to the electric motor 3. The required motor torque Tm can be accurately generated by accurately controlling the armature current Ia of the electric motor to the armature current target value Iat as shown in FIG.
[0062]
Incidentally, when the motor field current target value Ifmt is maintained at the motor field current target value Ifmt in the drive (D) range during reverse travel in the reverse (R) range, as shown by the dotted line in FIG. In order to maintain the state where the motor induced voltage E is high, the power generation capacity of the generator 7 is exceeded. Therefore, the armature current Ia of the electric motor 3 cannot flow the necessary armature current as shown by the dotted line in FIG. 12D, and the necessary motor torque Tm can be generated by the electric motor 3. Without affecting acceleration slip.
[0063]
In particular, since the automatic transmission 4 having a torque converter is connected to the output side of the engine 2, when the accelerator pedal 17 is released, the engine speed Ne decreases rapidly. Since the rotational speed of the generator 7 is also reduced, the power generation shortage state is increased. However, in the present embodiment, as described above, by performing the weakening control of the motor field current Ifm in the reverse (D) range, Since the motor induced voltage E is decreased and the generated current generated by the generator 7 is increased, the generated current is ensured even when the engine rotational speed Ne decreases near the idle rotational speed, and the armature current of the electric motor 3 is secured. Accurate motor control for generating an appropriate motor torque Tm can be performed by matching Ia with the armature current target value Iat.
[0064]
In addition, since the electric motor 3 is driven by surplus power generated by the generator 7 and the rear wheels 1RL and 1RR that are the driven wheels are driven, the acceleration of the vehicle can be improved.
At this time, since the electric motor 3 is driven with a surplus torque exceeding the road surface reaction force limit torque of the main drive wheels 1FL, 1FR, energy efficiency is improved and fuel efficiency is improved.
[0065]
Here, when the rear wheels 1RL and 1RR are always in the driving state, energy conversion corresponding to the conversion efficiency occurs because the energy conversion is performed several times in the order of mechanical energy → electric energy → mechanical energy. Thus, the acceleration performance of the vehicle is reduced as compared with the case where the vehicle is driven only by the front wheels 1FL and 1FR. For this reason, it is desirable to suppress the driving of the rear wheels 1RL and 1RR as deceleration. On the other hand, in the present embodiment, on the slippery road surface or the like, even if all of the output torque Te of the engine 2 is transmitted to the front wheels 1FL and 1FR, not all of them are used as driving force. A driving force that cannot be used effectively is output to the rear wheels 1RL and 1RR to improve acceleration.
[0066]
Further, in the above embodiment, when the gear ratio detected by the gear ratio detecting means falls below a preset gear ratio, that is, when the reverse (R) range is selected instead of the drive (D) range, the generator is Since the field current correction means for reducing and correcting the motor field current target value Ifmt is provided, it is accurately detected that the generator is in the power generation shortage state, and the power shortage state is detected. It is possible to reliably avoid falling into.
[0067]
Further, in the above embodiment, the motor rotation speed sensor 39 is provided as a motor rotation speed detection means for detecting the rotation speed of the motor, and the motor field current is based on the motor rotation speed Nm detected by the motor rotation speed sensor 39. Since the target value is calculated, the driving torque generated by the electric motor 3 can be accurately controlled.
[0068]
Furthermore, in the above embodiment, the field current correction means multiplies the motor field current target value calculated by the field current control means by a correction coefficient of less than 1 when the speed ratio is lower than the set speed ratio. Thus, the motor field current target value can be reliably corrected to decrease, and the power generation deficiency of the generator can be solved.
In the above embodiment, when the shift position of the automatic transmission 4 is detected by the shift position sensor 25 and is in the reverse (R) range, it is determined that the gear ratio is reduced and power shortage occurs. However, the present invention is not limited to this, and the input side rotational speed and the output side rotational speed of the automatic transmission 4 may be detected, and the gear ratio may be detected from these ratios.
[0069]
Moreover, in the said embodiment, although it replaced with ranges other than a reverse (R) range and the reverse (R) range was selected, the case where it judged that a power generation shortage generate | occur | produced was demonstrated, it is limited to this. In the four-wheel drive state, when power is shifted from the first speed gear position of the drive (D) range to the second speed gear position having a lower gear ratio, power generation is insufficient. By detecting a shift up to the 2nd gear position, the correction coefficient K of the motor field current target value Ifmt is smaller than that of the above embodiment._AThe motor field current target value Ifmt may be corrected to decrease. In this case, the gear ratio is detected by detecting the input side rotational speed and the output side rotational speed of the automatic transmission 4 and calculating the ratio thereof, or a gear shift command value output from a gear shift controller that controls the automatic transmission 4. It is preferable to detect whether the gear position is the first gear position or the second gear position.
[0070]
Furthermore, in the above-described embodiment, the case where the automatic transmission 4 is applied has been described. However, the present invention is not limited to this. A step transmission may be applied. In this case, the speed ratio of the continuously variable transmission is detected by detecting the input side rotational speed and the output side rotational speed of the continuously variable transmission, and the motor is changed when the predetermined speed ratio changes from the maximum speed ratio. The field current target value Ifmt is corrected to decrease or a correction coefficient K corresponding to the amount of change in the gear ratio._AMay be set to correct for decrease. A manual transmission may also be used.
[0071]
Furthermore, in the above embodiment, when the power shortage state is detected, the correction factor K is added to the motor field current target value Ifmt._AHowever, the present invention is not limited to this, and a new motor field current target value Ifmt is calculated by subtracting a predetermined correction coefficient from the motor field current target value Ifmt. You may do it.
[0072]
Still further, in the above embodiment, the generated voltage V of the generator 7 based on the armature current target value Iat and the motor induced voltage E._GAnd the generated voltage V_GAlthough the case where the field control output MF of the generator 7 is controlled based on the above has been described, the present invention is not limited to this, and the actual armature current target value Iat and the actual DC power supplied to the DC motor 3 detected by the current sensor 37 are described. The generator field current Ifg is calculated by multiplying the deviation ΔIa from the armature current Ia by the proportional control gain or by multiplying the integral value of the deviation ΔIa by the integral control gain, and according to the generator field current Ifg. The duty ratio may be calculated, and the power generation control output of this duty ratio may be supplied to the bipolar transistor 33.
[0073]
In the above embodiment, the case where the electromagnetic clutch 12 is applied as the clutch has been described. However, the present invention is not limited to this, and a fluid pressure clutch can also be applied. In this case, the fluid pressure clutch is supplied. The clutch engagement force may be controlled by electrically controlling the pressure control valve that controls the fluid pressure to be applied, and any other clutch capable of electrically controlling the clutch engagement force can be applied.
[0074]
Furthermore, although the case where the input shaft of the generator 7 is connected to the engine 2 via the belt 6 has been described in the above embodiment, the present invention is not limited to this, and the input shaft of the generator 7 is the output of the transfer. It may be connected to the rotating part from the side to the front wheels 1FL, 1FR. In this case, the load during idling of the engine 2 can be reduced.
[0075]
In the above embodiment, the motor rotation speed sensor 39 is applied as the motor rotation speed detection means, and the motor rotation speed sensor 39 directly detects the motor rotation speed Nm. However, the present invention is not limited to this. Wheel speed Vw detected by wheel speed sensors 24RL and 24RR_RLAnd Vw_RRAnd the motor rotation speed may be estimated based on the reduction gear ratio of the differential gear 13.
[0076]
In the above embodiment, the case where the present invention is applied to a four-wheel drive vehicle in which the front wheels 1FL and 1FR are main drive wheels and the rear wheels 1RL and 1RR are sub drive wheels has been described. However, the present invention is not limited to this. Instead of this, the rear wheels 1RL and 1RR may be the main driving wheels, and the front wheels 1FL and 1FR may be the secondary driving wheels.
In the above embodiment, the case where the present invention is applied to a four-wheel drive vehicle has been described. However, the present invention is not limited to this, and includes two or more drive wheels in the front-rear direction. The present invention can be applied when the wheels are driven by an internal combustion engine and the remaining driven wheels are driven by an electric motor, and the electric motor drives the wheels by a generator that is rotationally driven by a rotational drive source such as an internal combustion engine. The present invention can be applied to an electric drive device that drives the motor.
[Brief description of the drawings]
FIG. 1 is a schematic device configuration diagram showing a first embodiment of the present invention.
FIG. 2 is a block diagram of a control system in the first embodiment.
FIG. 3 is a functional block diagram showing a 4WD controller according to the first embodiment.
FIG. 4 is a flowchart showing a control processing procedure in the 4WD controller in the first embodiment.
FIG. 5 is a flowchart illustrating an example of a processing procedure of a surplus torque calculation unit according to the first embodiment.
FIG. 6 is a flowchart showing an example of a processing procedure of a target torque control unit in the first embodiment.
FIG. 7 is a diagram showing an engine torque calculation map showing a relationship between a throttle opening θ and an engine torque Te using an engine rotation speed Ne as a parameter.
FIG. 8 is a flowchart illustrating an example of a processing procedure of a surplus torque conversion unit according to the first embodiment.
FIG. 9 is a diagram showing an armature current target value calculation map showing a relationship between a motor torque target value and an armature current target value using a motor field current target value as a parameter.
FIG. 10 is a time chart for explaining the operation of the embodiment.
FIG. 11 is a characteristic diagram showing the relationship between the vehicle speed and the engine rotation speed using the first-speed gear position of the drive range and the reverse range as parameters.
FIG. 12 is a time chart for comparing the operation of the drive range and the reverse range of the embodiment.
FIG. 13 is a characteristic diagram showing a relationship between a power generation capacity line and a motor back electromotive force.
[Explanation of symbols]
1FL, 1FR Front wheel
1RL, 1RR Rear wheel
2 Engine
3 DC motor
4 Automatic transmission
7 Generator
8 4WD controller
10 Junction box
11 Reducer
12 Electromagnetic clutch
23 Engine speed sensor
24FL-24RR Wheel speed sensor
25 Shift position sensor
FC field coil
SC stator coil
37 Current sensor
39 Rotational speed sensor for motor

Claims (4)

A main drive source that drives the main drive wheel via a transmission, a generator that is driven by the main drive source, and an electric motor that is driven by the electric power of the generator and can transmit drive torque to the slave drive wheel In the vehicle driving force control apparatus provided,
A field current control means for controlling the field current of the motor, a speed ratio detection means for detecting a speed ratio of the transmission, and the generator is insufficient in power generation based on the speed ratio detected by the speed ratio detection means And a field current correction unit that corrects the field current controlled by the field current control unit to decrease so that the counter electromotive force generated by the electric motor is reduced when it is determined that a state is reached. A driving force control device for a vehicle. The field current correction means determines that the generator is in an insufficient power generation state when the speed ratio detected by the speed ratio detection means falls below a preset speed ratio, and the field current control means 2. The vehicle driving force control device according to claim 1, wherein the field current to be controlled is reduced and corrected. An electric motor rotation speed detecting means for detecting the rotation speed of the electric motor is provided, and the field current control means calculates a motor field current target value based on the electric motor rotation speed detected by the electric motor rotation speed detection means. The vehicle driving force control device according to claim 1 , wherein the vehicle driving force control device is configured. The field current correction means is configured to multiply the correction value of less than 1 by the motor field current target value calculated by the field current control means when the speed ratio is lower than the set speed ratio. The vehicle driving force control apparatus according to claim 3.

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