JP3646643B2 - Control device for four-wheel drive vehicle - Google Patents

Description

【０１１５】
ＳＤ３２では、受入制限値ＷINに基づいてＲＭＧ７０の出力トルクの下限値ＴRMGminp が算出される。すなわち、数式５および数式６からＰRMG が求められ、これがＲＭＧ７０の最小出力ＰRMGminp とされる。次いで、このＰRMGminp とＲＭＧ７０の回転速度ＮRMG から数式７を満足するＴRMG が求められ、これがＲＭＧ７０の最小出力トルクＴRMGminp とされる。
【０１１６】

【０１１７】
続いて、前記第２電動機作動制御手段３３２に対応するＳＤ３３では、ＲＭＧ７０の出力トルク基本値ＴRMGbase を、数式８から算出する。この出力トルク基本値ＴRMGbase は、ＲＭＧ７０から出力される基本トルクであり、原則的にはこの値が出力されるようにＲＭＧ７０が駆動されるが、実際には、後述の上下限ガード処理後の値が出力されるようにＲＭＧ７０が駆動される。数式８において、ＧＲＲは副駆動装置１２（減速装置７２）の減速比である。
【０１１８】
（数式８）
ＴRMGbase ＝Ｔdrv ×Ｋtr／ＧＲＲ
【０１１９】
そして、前記第２電動機作動制限手段３３６に対応するＳＤ３４では、上記出力トルク基本値ＴRMGbase に対して、蓄電装置１１２に由来する制限およびＲＭＧ７０の温度に由来する制限を行うための、上記ＴRMGmaxp およびＴRMGminp 、前記ＴRMGmaxおよびＴRMGminによる上下限ガード処理が数式９および数式１０に従って実行され、上下限ガード処理後の値がＲＭＧ７０の出力トルク仮決定値ＴRMGtmpとして決定される。
【０１２０】
（数式９）
ＴRMGminp ≦ＴRMGbase ≦ＴRMGmaxp
（数式１０）
ＴRMGmin≦ＴRMGbase ≦ＴRMGmax
【０１２１】
図１８に戻って、ＳＤ４では、たとえば図２１に示すフロントモータトルク仮決定ルーチンが実行されることにより、ＭＧ１６の出力トルク仮決定値ＴMGtmp が算出される。すなわち、図２１のＳＤ４１では、持出制限値ＷOUT に基づいてＭＧ１６の出力トルクの上限値ＴMGmax が算出される。すなわち、数式１１から上記ＲＭＧ７０の出力トルク仮決定値ＴRMGtmpに基づいてＲＭＧ７０の出力ＰRMG が算出され、そのＲＭＧ７０の出力ＰRMG からＭＧ１６の最大出力ＰMG（＝ＷOUT −ＰRMG ）が算出され、数式１２からそのＭＧ１６の最大出力ＰMG（＝ＷOUT −ＰRMG ）に基づいてＭＧ１６の最大出力トルクＴMGが求められ、これがＴMGmaxpとされる。また、ＲＭＧ７０の出力ＰRMG からＭＧ１６の最小出力ＰMG（＝ＷIN−ＰRMG ）が算出され、数式１２からそのＭＧ１６の最小出力ＰMG（＝ＷIN−ＰRMG ）に基づいてＭＧ１６の最小出力トルクＴMGが求められ、これがＴMGminpとされる。数式１２において、ＰMGloss（ＮMG，ＴMG）はＭＧ１６の損失である。
【０１２２】
（数式１１）
ＰRMG ＝ＮRMG ×ＴRMGtmp＋ＰRMGloss （ＮRMG ，ＴRMG ）
（数式１２）
ＮMG×ＴMG＋ＰMGloss（ＮMG，ＴMG）＝ＰMG
【０１２３】
次いで、前記第１電動機作動制御手段３３０に対応するＳＤ４２では、ＭＧ１６の出力トルク基本値ＴMGbaseを、数式１３から運転者要求トルクＴdrv およびＲＭＧ７０の出力トルク仮決定値ＴRMGtmp、エンジン出力トルク基本値ＴEbase に基づいて算出し、その出力トルク基本値ＴMGbaseがＭＧ１６から出力されるように指令する。数式１３において、ＧＲＦは主駆動装置（遊星歯車装置１８および無段変速機２０）の減速比である。数式１３では、運転者要求トルクＴdrv からＲＭＧ７０の出力トルク仮決定値ＴRMGtmpに減速比ＧＲＲを差し引いた値に基づいてＭＧ１６の出力トルク基本値ＴMGbaseが算出されているので、たとえばＳＤ３４においてＲＭＧ７０の出力トルクが制限されたときは、その分だけＭＧ１６の出力トルク基本値ＴMGbaseが増加させられて、車両の合計駆動力或いは回生制動力が一定に保持されるようになっている。したがって、本実施例では、このＳＤ４２は、前記第１電動機作動増大手段３３８にも対応している。
【０１２４】
（数式１３）
ＴMGbase＝（Ｔdrv −ＴRMGtmp×ＧＲＲ）／ＧＲＦ−ＴEbase
【０１２５】
続いて、前記第１電動機作動制限手段３３４に対応するＳＤ４３では、上記出力トルク基本値ＴMGbaseに対して、蓄電装置１１２に由来する制限およびＭＧ１６の温度に由来する制限を行うための、上記ＴMGmaxpおよびＴMGminp、前記ＴMGmax およびＴMGmin による上下限ガード処理が数式１４および数式１５に従って実行され、上下限ガード処理後の値がＭＧ１６の出力トルク仮決定値ＴMGtmp として決定される。
【０１２６】
（数式１４）
ＴMGminp≦ＴMGbase≦ＴMGmaxp
（数式１５）
ＴMGmin ≦ＴMGbase≦ＴMGmax
【０１２７】
図１８に戻って、ＳＤ５では、前輪（車軸）の仮トルクＴftmpが数式１６から算出され、後輪（車軸）の仮トルクＴrtmpが数式１７から算出される。
【０１２８】
（数式１６）
Ｔftmp＝（ＴMG＋ＴEbase ）×（ＮIN／ＮOUT ）×ＥＦCVT ×ＧＲＦ
（数式１７）
Ｔrtmp＝ＴRMGtmp×ＧＲＲ
【０１２９】
次に、ＳＤ６において、上記後輪の仮トルク｜Ｔrtmp｜が、前輪の仮トルクＴftmpと後輪の仮トルクＴrtmpとの合計値｜Ｔftmp＋Ｔrtmp｜に後輪トルク分配比Ｋtrを掛けた値以下であるか否か、すなわち、合計値｜Ｔftmp＋Ｔrtmp｜に対する後輪の仮トルク｜Ｔrtmp｜の割合（｜Ｔrtmp｜／｜Ｔftmp＋Ｔrtmp｜）が後輪トルク分配比Ｋtr以下であるか否かが判断される。このＳＤ６の判断が肯定される場合は、ＳＤ７において、上記後輪の仮トルクＴRMGtmpがＲＭＧ７０の出力トルクＴRMG として決定される。
【０１３０】
しかし、上記ＳＤ６の判断が否定される場合は、ＳＤ８において、ＲＭＧ７０の出力トルクが再計算された後、上記ＳＤ７が実行される。このＳＤ８では、たとえば図２２に示すリヤモータ出力トルク再計算ルーチンが実行される。図２２のＳＤ８１では、数式１８から前輪仮トルクＴftmpと前輪トルク配分比（１−Ｋtr）および後輪トルク配分比Ｋtrの割合〔Ｋtr／（１−Ｋtr）〕とに基づいて後輪のトルクＴrtmpが算出され、ＳＤ８２では、数式１９からその後輪のトルクＴrtmpと副駆動装置１２の減速比ＧＲＲとに基づいてＲＭＧ７０の仮出力トルク値ＴRMGtmpが算出される。ここで、たとえば、前記ＳＤ４３によりＭＧ１６の出力トルクが制限されたために、前輪の仮トルクＴftmpと後輪の仮トルクＴrtmpとの合計値｜Ｔftmp＋Ｔrtmp｜に対する後輪の仮トルク｜Ｔrtmp｜の割合（｜Ｔrtmp｜／｜Ｔftmp＋Ｔrtmp｜）が後輪トルク分配比Ｋtrを上まわった場合には、上記数式１８によって、前輪仮トルクＴftmpおよび後輪仮トルクＴrtmpの分配比（Ｔrtmp／Ｔftmp）が予め定められた目標分配比である前輪トルク配分比（１−Ｋtr）および後輪トルク配分比Ｋtrの分配比〔Ｋtr／（１−Ｋtr）〕となるように、すなわち実際の前後輪の駆動力配分比或いは回生制動力配分比が目標分配比〔Ｋtr／（１−Ｋtr）〕となるように後輪仮トルクＴrtmpが上記ＭＧ１６の出力トルクの制限量に対応して低減されるので、上記ＳＤ８は前記第２電動機作動低減手段３４０に対応している。
【０１３１】
（数式１８）
Ｔrtmp＝Ｔftmp×〔Ｋtr／（１−Ｋtr）〕
（数式１９）
ＴRMGtmp＝Ｔrtmp×ＧＲＲ
【０１３２】
上述のように、本実施例によれば、ＭＧ１６（第１電動機）とＲＭＧ７０（第２電動機）との熱定格の相互関係が特定の状態とされるため、前後輪駆動車両がその駆動力バランスを考慮したものとされることができ、走行安定性が保持されることができる。
【０１３３】
また、本実施例によれば、ＭＧ１６（第１電動機）の熱定格がＲＭＧ７０（第２電動機）の熱定格よりも高くされたものであることから、後輪８０、８２を駆動するＲＭＧ７０の熱定格が前輪６６、６８を駆動するＭＧ１６の熱定格よりも低く、後輪側のＲＭＧ７０の出力が先に制限されるが、後輪８０、８２であるために比較的車両の安定性が保持される利点がある。
【０１３４】
また、本実施例によれば、第２電動機作動制限手段３３６（ＳＤ３４）によるＲＭＧ７０の作動制限時（駆動作動制限時或いは回生作動制限時）において、第１電動機作動増大手段３３８（ＳＤ４２）によりＭＧ１６の作動（駆動作動或いは回生作動）が増大させられるため、比較的車両の安定性を保ちつつ、車両の全駆動力或いは回生制動力が確保される。たとえば、ＲＭＧ７０の出力制限時においては運転者要求トルクＴdrv に対応する車両の全駆動力を変化させないようにＭＧ１６の出力が増大させられ、ＲＭＧ７０の回生制限時においては車両の全回生制動トルクを変化させないようにＭＧ１６の回生が増大させられることにより、車両の安定性が保持されつつ、車両の全駆動力或いは回生制動力が確保される。
【０１３５】
また、本実施例によれば、第１電動機作動制限手段３３４（ＳＤ４３） によるＭＧ１６の作動制限時において、第２電動機出力低減手段３４０（ＳＤ８）により前後輪の分配比を目標分配比とするためにすなわち後輪８０、８２のトルク分配比をＫtrとするためにＲＭＧ７０の作動が低減させられるため、車両の安定性が確保される。たとえば、ＭＧ１６の出力制限時においては前後輪のトルク分担比すなわち後輪トルク分担比Ｋtrが維持されるように、またはそれよりも前輪駆動（ＦＦ）となるようにＲＭＧ７０の出力が低減させられ、また、ＭＧ１６の回生制限時においても同様にＲＭＧ７０の回生が低減させられることにより、車両の安定性が保持されつつ、車両の全駆動力或いは回生制動力が確保される。
【０１３６】
図２３は、図９の他の制御作動を説明するフローチャートである。このフローチャートにおいては、図９に比較して、ＳＡ１が削除され、且つＳＡ２の判断が肯定されたときに実行されるＳＡ３０が設けられている点において相違し、他は同様である。図９と共通する部分には同一の符号を付して説明を省略する。
【０１３７】
上記ＳＡ３０では、外気温度が路面摩擦係数変化を生じ得るような所定温度以下の低温状態であり、且つ路面勾配が所定角度以上の登坂走行であるか否かが判断される。この登坂走行は、たとえば図示しない前後Ｇセンサからの信号に基づいて判断される。或いは、車両の停止時或いはアクセルペダル１２２が操作されない惰行走行時に記憶された前後加速度と発進直前の加速度との加速度差が路面勾配に対応することを利用して、その加速度差が所定値を越えた場合に登坂走行を判定してもよい。この場合、平坦路における高加速度発進においても登坂と誤判定されない利点がある。
【０１３８】
上記ＳＡ３０の判断が肯定される場合は、ＳＡ１６以下が実行されることにより相対的に大きな駆動力を得ることができる第１出力トルク領域が選択され、その第１出力トルク領域に従ってＲＭＧ７０が駆動される。これにより、大きな駆動力が得られる４輪駆動走行が行われる。しかし、上記ＳＡ３０の判断が否定される場合は、ＳＡ１９以下が実行されることにより、第１出力トルク領域よりは最大トルクが小さく設定された第２出力トルク領域が選択されるので、その第２出力トルク領域に従ってＲＭＧ７０が駆動される。これにより、平坦路や高μ路においては十分であるが、電力消費が抑制された４輪駆動走行が行われ、ＲＭＧ７０の駆動負荷が軽減される。
【０１３９】
なお、上記ＳＡ３０において、外気温度が路面摩擦係数変化を生じ得るような所定温度以下の低温状態であるか、或いは路面勾配が所定角度以上の登坂走行であるか否かが判断されるようにしてもよい。この場合、外気温度が路面摩擦係数変化を生じ得るような所定温度以下の低温状態であるとき、および路面勾配が所定角度以上の登坂走行であるときには、共にＳＡ１６以下が実行されることにより相対的に大きな駆動力を得ることができる第１出力トルク領域が選択され、その第１出力トルク領域に従ってＲＭＧ７０が駆動される。しかし、外気温度が路面摩擦係数変化を生じ得るような所定温度以下の低温状態でなく、しかも路面勾配が所定角度以上の登坂走行でない場合に、ＳＡ１９以下が実行されることにより、第１出力トルク領域よりは最大トルクが小さく設定された第２出力トルク領域が選択されるので、その第２出力トルク領域に従ってＲＭＧ７０が駆動される。
【０１４０】
図２４は、前記ハイブリッド制御装置１０４などに設けられた他の制御機能の要部、すなわち前輪６６、６８の駆動力に従った車両の登坂発進時において、車両の駆動力を一時的に高めるために所定の駆動力配分比に従ってＲＭＧ７０を作動させ、後輪８０、８２からも駆動力を発生させる高μ路アシスト制御を説明する機能ブロック線図である。図２４において、目標出力決定手段３４８は、たとえば図２５に示す予め記憶された関係から実際の運転者による出力操作手段の操作程度たとえばアクセルペダル１２２の操作量（アクセル開度）θ_A と車速Ｖとに基づいて目標駆動力Ｆ_T1を決定する。上記図２５に示す関係は、運転者の要求駆動力或いは要求加速力を実現するために予め実験的に求められたものである。
【０１４１】
坂路発進アシスト制御手段３５０は、車両の発進操作に先立ち且つアクセルペダル１２２の操作により車両が所定速度に到達するまで、道路勾配に対応した大きさの駆動力であって、登坂発進時の車両の後退速度すなわちずり落ち速度が零より大きな所定車速以下たとえば１〜３km/h程度の微速とする大きさの駆動力を車両に付与するようにする。すなわち、坂路発進アシスト制御手段３５０は、車両が発進しようとする路面の勾配（角度）検出するためにたとえば勾配に対応する停車時前後加速度Ｇ_xstpを車両停止且つブレーキ操作時の図示しない前後加速度センサの出力信号に基づいて記憶する路面勾配検出手段３５２と、たとえば図２６に示す予め記憶された関係から実際の勾配に対応する停車時前後加速度Ｇ_xstpに基づいて登坂発進時の後退を抑制するために付加すべき仮補正駆動力ｄＦ_K を決定する仮補正駆動力決定手段３５４と、その仮補正駆動力決定手段３５４により決定された仮補正駆動力ｄＦ_K に基づいて、たとえば図２７に示すように、出力開始時にはたとえば０．２秒程度の立ち上がり期間（ｔ₀ 〜ｔ₁ ）で相対的に速やかに増加して仮補正駆動力ｄＦ_K に到達するが、出力終了時にはたとえば１乃至２秒程度の立ち下がり期間（ｔ₂ 〜ｔ₃ ）でその仮補正駆動力ｄＦ_K から相対的に緩やかに減少する補正駆動力ｄＦを発生させる補正駆動力発生手段３５５と、その補正駆動力ｄＦを車両の駆動力に付与するために前記目標駆動力Ｆ_T1に加算する補正駆動力付与手段３５６とを備えている。上記図２６に示す関係は、登坂発進時の車両の後退速度すなわちずり落ち速度が零より大きな所定車速以下たとえば１〜３km/h程度の微速となるように予め実験的に求められたものであり、所定の勾配範囲内すなわち停車時前後加速度Ｇ_xstpがＧ₁ 乃至Ｇ₂ の範囲内において、停車時前後加速度Ｇ_xstpの増加に伴って比例的に仮補正駆動力ｄＦ_K が増加するように決定されている。停車時前後加速度Ｇ_xstpがＧ₁ よりも小さい場合は補正駆動力ｄＦを付与しなくても後退速度が緩やかであり、停車時前後加速度Ｇ_xstpがＧ₂ よりも大きい場合はそれ以後の後退速度を路面傾斜に伴って大きくするために仮補正駆動力ｄＦ_K の増加が飽和させられている。
【０１４２】
また、アクセル開度θ_A がたとえば図２８に示すような予め設定された関係θ_A1＝ｆ（Ｇ_xstp、Ｗ）から実際の路面勾配Ｇ_xstpおよび車重Ｗに基づいて求められた判断基準値θ_A1を越えたか否かに基づいて駆動力の坂路発進アシスト補正が不要であるか否かを判定する補正開始不可判定手段３５８と、アクセル開度θ_A が予め設定された判断基準値θ_A2を越えたか否かに基づいて補正駆動力ｄＦを付与する登坂発進アシスト制御を中止するか否かを判定する補正中止判定手段３６０とが設けられており、上記坂路発進アシスト制御手段３５０すなわち補正駆動力付与手段３５６は、補正開始不可判定手段３５８により駆動力の補正が不要であると判定された場合は登坂発進アシスト制御は行わないが、アクセル開度θ_A がたとえば１０°程度の勾配に対応する２０％程度の判断基準値θ_A1を越えたと判定された場合は登坂発進アシスト制御を開始する。また、上記坂路発進アシスト制御手段３５０すなわち補正駆動力付与手段３５６は、登坂発進アシスト制御中において上記補正中止判定手段３６０によりアクセル開度θ_A が予め設定された判断基準値θ_A2を越えたと判定された場合はアクセルペダル１２２の加速操作に基づく駆動力が高められるので、発進アシスト制御を中止或いは終了させる。
【０１４３】
車速Ｖが１〜３ｋｍ／ｈ程度に予め設定された判断基準車速Ｖ₁ 以上であるか否かを判定する車速判定手段３６２と、ブレーキペダル１２４の非操作が所定時間Ｔ₁ 以上継続されているか否かを判定するブレーキ非操作継続判定手段３６４とが設けられている。前記坂路発進アシスト制御手段３５０すなわち補正駆動力付与手段３５６は、車速判定手段３６２により車速Ｖが予め設定された判断基準車速Ｖ₁ 以上ではない（判断基準車速Ｖ₁ よりも低い）と判定されるか、或いはブレーキ非操作継続判定手段３６４によりブレーキペダル１２４が所定時間Ｔ₁ 以上連続操作されていないと判定された場合には上記補正駆動力ｄＦを車両の駆動力に付与するが、車速Ｖが予め設定された判断基準車速Ｖ₁ 以上であると判定されるか、或いはブレーキペダル１２４の非操作が所定時間Ｔ₁ 以上継続されている場合には上記補正駆動力ｄＦを車両の駆動力に付与する登坂発進アシスト制御は行わない。すなわち、上記坂路発進アシスト制御手段３５０すなわち補正駆動力付与手段３５６による登坂発進アシスト制御は、車両の停車中或いは車速Ｖが極めて低い判断基準車速Ｖ₁ よりも低い場合、ブレーキオン操作がされているか或いはオフ操作がされていても所定時間Ｔ₁ 以上連続していない場合に行われる。
【０１４４】
原動機駆動制御手段３６６は、補正駆動力付与手段３５６により補正駆動力ｄＦが加算された目標駆動力Ｆ_T2（＝Ｆ_T1＋ｄＦ）が得られるように車両の原動機の出力を制御する。たとえば、前輪系の原動機であるエンジン１４および／またはＭＧ１６から目標駆動力Ｆ_T1を出力させ、後輪系の原動機であるＲＭＧ７０から登坂発進のための補正駆動力ｄＦを出力させることにより、アクセルペダル１２２の操作前では専ら補正駆動力ｄＦにより車両の後退を１〜３ｋｍ／ｈ程度の僅かな速度にとどめ、アクセルペダル１２２の操作により登坂発進が開始された場合は４輪駆動状態として車両の総駆動力を目標駆動力Ｆ_T2とする。
【０１４５】
図２９および図３０は、本実施例のハイブリッド制御装置１０４の制御作動の要部を説明するフローチャートであって、図２９は駆動力制御ルーチンを、図３０は登坂発進補正駆動力算出ルーチンをそれぞれ示している。
【０１４６】
図２９において、ＳＥ１では、図示しないセンサの出力信号から車速Ｖ、アクセルペダル１２２の操作量であるアクセル開度θ_A 、前後加速度Ｇ_x などが読み込まれる。次いで、前記目標出力決定手段３４８に対応するＳＥ２では、たとえば図２５に示す予め記憶された関係から実際のアクセルペダル１２２の操作量（アクセル開度）θ_A と車速Ｖとに基づいて、運転者の要求駆動力である目標駆動力Ｆ_T1が決定される。続いて、前記坂路発進アシスト制御手段３５０に対応するＳＥ３およびＳＥ４では、車両の発進操作に先立ち且つアクセルペダル１２２の操作により車両が所定速度に到達するまで、道路勾配に対応した大きさの駆動力であって、登坂発進時の車両の後退速度すなわちずり落ち速度が零より大きな所定車速以下たとえば１〜３km/h程度の微速とする大きさの駆動力が車両に付与されるようにする。
【０１４７】
図３０は、上記ＳＥ３の作動を詳しく説明する登坂発進補正駆動力を算出するルーチンを示している。図３０において、前記補正開始不可判定手段３５８に対応するＳＥ３１では、アクセル開度θ_A がたとえば図２８に示すような予め設定された関係θ_A1＝ｆ（Ｇ_xstp、Ｗ）から実際の路面勾配Ｇ_xstpおよび車重Ｗに基づいて求められた判断基準値θ_A1を越えたか否かに基づいて駆動力の坂路発進アシスト補正が不要であるか否かが判断される。このＳＥ３１の判断が肯定された場合は、アクセルペダル１２２が発進のためにたとえば２０％以上となるように比較的大きく操作された状態であるので、ＳＥ３２において、算出される補正駆動力ｄＦを零とするために路面勾配に対応する停車時前後Ｇセンサ値Ｇ_xstpの内容が強制的に「０」に設定されることにより、実質的に補正駆動力の算出が開始されないようにする。
【０１４８】
しかし、上記ＳＥ３１の判断が否定される場合は、アクセルペダル１２２が未だ発進操作されない状態であるので、前記路面勾配検出手段３５２に対応するＳＥ３３、ＳＥ３４、ＳＥ３５が実行される。ＳＥ３３では車両が停車中であるか否かがたとえば車速Ｖに基づいて判断され、ＳＥ３４ではブレーキペダル１２４が操作されているか否かがたとえば図示しないブレーキスイッチからの出力信号に基づいて判断される。ＳＥ３３およびＳＥ３４の判断が共に肯定された場合は、ＳＥ３５において、そのときの前後Ｇセンサの出力値が路面勾配を表す重力値Ｇ_xstpとして記憶される。
【０１４９】
次いで、前記補正中止判定手段３６０に対応するＳＥ３６において、アクセルペダル１２２の操作による発進時の駆動力増加により登坂発進のための補正が不要となったか否かを判断するために、アクセル開度θ_A が予め設定された判断基準値θ_A2を越えたか否かが判断される。このＳＥ３６の判断が肯定される場合は、ＳＥ３７において算出される補正駆動力ｄＦを零とするために路面勾配に対応する停車時前後Ｇセンサ値Ｇ_xstpの内容が優先的に「０」に設定されることにより、実質的に補正駆動力の算出が開始されないようにする。
【０１５０】
しかし、上記ＳＥ３６の判断が否定される場合は、前記仮補正駆動力決定手段３５４に対応するＳＥ３８において、たとえば図２６に示す予め記憶された関係から実際の勾配に対応する停車時前後加速度Ｇ_xstpに基づいて登坂発進時の後退を抑制するために付加すべき仮補正駆動力ｄＦ_K が決定される。次いで、前記補正駆動力発生手段３５５に対応するＳＥ３９において、上記仮補正駆動力ｄＦ_K に基づき、たとえば図２７に示すように、補正駆動力付与開始直後にはたとえば０．２秒程度の立ち上がり期間（ｔ₀ 〜ｔ₁ ）で相対的に速やかに増加して仮補正駆動力ｄＦ_K に到達するが、補正駆動力付与終了時にはたとえば１乃至２秒程度の立ち下がり期間（ｔ₂ 〜ｔ₃ ）でその仮補正駆動力ｄＦ_K から相対的に緩やかに減少する補正駆動力ｄＦが発生させられる。
【０１５１】
前記ＳＥ３３の判断が否定される場合は、前記車速判定手段３６２に対応するＳＥ４０において、実際の車速Ｖが１〜３ｋｍ／ｈ程度に予め設定された判断基準車速Ｖ₁ 以上となったか否かが判断される。このＳＥ４０の判断が否定される場合は、車両が未だ登坂発進により車速が出ない状態であるので、登坂発進のための補正駆動力を付与するための制御を継続させるためにＳＥ３６以下が実行されるが、そのＳＥ４０の判断が肯定される場合は、登坂発進時に車両がすでに前進開始させられた状態であって登坂発進のための補正駆動力を付与する必要がなくなった状態であるので、その補正駆動力を付与する制御を実質的に終了させるために前記ＳＥ３２以下が実行される。
【０１５２】
また、前記ＳＥ３４の判断が否定される場合は、前記ブレーキ非操作継続判定手段３６４に対応するＳＥ４１において、ブレーキペダル１２４がたとえば１秒程度に設定された所定時間Ｔ₁ 以上連続操作されていないか否かが判断される。このＳＥ４１の判断が否定される場合は、運転者の前進意図が存在する可能性がある状態であるので、登坂発進のための補正駆動力を付与するための制御を継続させるためにＳＥ３６以下が実行されるが、そのＳＥ４１の判断が肯定される場合は、運転者の前進意図が存在しないと考えられ、登坂路の車両のずり下がりを従来通りにした方がよい状態であるので、その補正駆動力を付与する制御を実質的に終了させるために前記ＳＥ３２以下が実行される。
【０１５３】
次いで、図２９に戻って、前記補正駆動力付与手段３５６に対応するＳＥ４では、上記ＳＥ３９において算出された補正駆動力ｄＦを車両の駆動力に付与するために、前記ＳＥ２において求められた目標駆動力Ｆ_T1に加算されることにより補正後の最終的な目標駆動力Ｆ_T2が算出される。そして、前記原動機駆動制御手段３６６に対応するＳＥ５において、ＳＥ３９において算出された補正駆動力ｄＦが加算された目標駆動力Ｆ_T2（＝Ｆ_T1＋ｄＦ）が得られるように車両の原動機の出力が制御する。たとえば、前輪系の原動機であるエンジン１４および／またはＭＧ１６から目標駆動力Ｆ_T1を出力させ、後輪系の原動機であるＲＭＧ７０から登坂発進のための補正駆動力ｄＦを出力させることにより、車両の総駆動力が目標駆動力Ｆ_T2とされる。
【０１５４】
なお、上記ＳＥ４では、ＳＥ３１（補正開始不可判定手段３５８）により駆動力の補正が不要であると判定された場合、登坂発進アシスト制御中においてＳＥ３６（上記補正中止判定手段３６０）によりアクセル開度θ_A が予め設定された判断基準値θ_A2を越えたと判定された場合、ＳＥ４０（車速判定手段３６２）により車速Ｖが予め設定された判断基準車速Ｖ₁ 以上ではない（判断基準車速Ｖ₁ よりも低い）と判定される場合、或いはＳＥ４１（ブレーキ非操作継続判定手段３６４）によりブレーキペダル１２４が所定時間Ｔ₁ 以上連続して操作されていないと判定された場合には、停車時前後加速度Ｇ_xstpが零に設定され且つそれから求められる補正駆動力ｄＦも零とされるので、実質的に補正駆動力ｄＦを車両の駆動力に付与する登坂発進アシスト制御が行われない。
【０１５５】
上述のように、本実施例の車両の駆動力制御において、坂路発進アシスト制御手段３５０によれば、道路勾配を表す停車時前後加速度Ｇ_xstpに対応して車両の駆動輪に駆動力を付与する車両の駆動制御を行う場合に、車両の登坂発進時において後退車速が零より大きい所定車速以下となるように車両の駆動力Ｆ_T2（＝Ｆ_T1＋ｄＦ）が設定されることから、車両の坂路発進に際してはアクセルペダル１２２の踏込前では所定車速以下で僅かに後退させられるので、車両のずり下がりが抑制されるとともに運転者が道路勾配を正確に知ることができる。このため、運転者は車両の発進に際して坂路勾配に応じて踏込を行うことができるようになる。すなわち、重力に基づく車両後退方向の付勢力と摩擦などの固定クリープ力との差である従来の車両の後退力Ｆ_R は、図３１に示すように路面傾斜角すなわち停車時前後加速度Ｇ_xstpが大きくなるほど大きくなる性質があるが、前述のように仮補正駆動力ｄＦ_K が図２６に示す関係から停車時前後加速度Ｇ_xstpが大きくなるほど大きくなるように決定されて前進方向の車両駆動力に付与されていることから、上記重力に基づく車両後退方向の付勢力と目標駆動力Ｆ_T2（車両停止中では仮補正駆動力ｄＦ_K となる）との差である実際の後退力Ｆ_R ' は上記従来の車両の後退力Ｆ_R よりも小さくされ、且つ略一定とされている。たとえば、停車時前後加速度Ｇ_xstpが順次大きくなるＧ_a 、Ｇ_b 、Ｇ_c において、従来の後退力はＦ_Ra、Ｆ_Rb、Ｆ_Rcであったのに対し、本実施例では仮補正駆動力ｄＦ_K 分だけ小さなＦ_Ra' 、Ｆ_Rb' 、Ｆ_Rc' とされており、それらＦ_Ra' 、Ｆ_Rb' 、Ｆ_Rc' は相互に略同等の値とされているのである。
【０１５６】
また、本実施例によれば、道路勾配を表す停車時前後加速度Ｇ_xstpに対応して車両の駆動輪に駆動力を付与する車両の駆動制御を行う場合に、登坂発進に際して、ブレーキ非操作継続判定手段３６４により車両の停車中にブレーキペダル１２４の非操作継続時間が１秒程度の所定のＴ₁ 時間よりも長いと判定された場合には、道路勾配に対応した駆動力ｄＦの付与が中止されることから、運転者の前進意図のない状態では車両のずり下がりが許容されるので、運転者に道路勾配の程度を知らせることができる。
【０１５７】
また、本実施例の補正駆動力付与手段３５６によれば、車両の登坂発進時に道路勾配を表す停車時前後加速度Ｇ_xstpに対応して駆動輪に駆動力を付与する車両の駆動制御を行う場合に、道路勾配に対応した駆動力ｄＦの付与を実行開始する時には速やかに駆動力を上昇させ、道路勾配に対応した駆動力ｄＦの付与の中止或いは終了時には緩やかに駆動力を減少させられることから、駆動力ｄＦの付与の実行を開始する時には登坂路発進時でのずり下がりの抑制が速やかに行われるとともに、駆動力ｄＦの付与の中止或いは終了時には違和感なく駆動力の付与が中止される。
【０１５８】
また、本実施例によれば、前輪６６、６８および後輪８０、８２の一方を第１原動機たとえばエンジン１４およびＭＧ１６で駆動可能とし、他方を第２原動機たとえばＭＧ７０により駆動可能とした４輪駆動車において、その４輪駆動車の制御装置が、運転者の出力操作手段の操作程度たとえばアクセル開度θ_A と車速Ｖとに基づき目標駆動力Ｆ_T1が求められ（目標出力決定手段３４８）、その目標駆動力Ｆ_T1に基づいて前輪側および後輪側から出力すべき駆動力Ｆ_T2が、車両発進時において道路勾配を表す停車時前後加速度Ｇ_xstpに基づいて補正された値となるように前輪６６、６８および後輪８０、８２の駆動力が制御される（補正駆動力発生手段３５５、補正駆動力付与手段３５６）ので、運転者の要求に合った目標駆動力が達成されると同時に、登坂発進走行時にはその勾配に合った前後輪の駆動力配分とされる。
【０１５９】
また、本実施例によれば、前記路面道路勾配を表す停車時前後加速度Ｇ_xstpに対応して車両の駆動輪に駆動力を付与する制御すなわち登坂アシスト制御を行う車両の駆動制御において、仮補正駆動力決定手段３５４により所定の道路勾配の範囲内すなわちＧ₁ 乃至Ｇ₂ の範囲内において後退車速が所定車速以下となるように道路勾配に対応して車両の駆動力が設定されることから、道路勾配が所定の道路勾配を越える場合には、後退車速が所定車速以下となるように設定される車両の駆動力がそれ以上増加させられなくなるので、運転者が道路勾配を一層正確に知ることができる。
【０１６０】
また、本実施例によれば、前記仮補正駆動力決定手段３５４、補正駆動力発生手段３５５、補正駆動力付与手段３５６により、路面道路勾配を表す停車時前後加速度Ｇ_xstpに対応して車両の駆動輪に駆動力を付与するに際して、車両の登坂発進時において後退車速が零より大きい所定車速以下となるように車両の駆動力Ｆ_T2（＝Ｆ_T1＋ｄＦ）が設定される場合に、その所定車速は数キロメータたとえば１乃至３km/hの車速とされるので、登坂路のずり下がりが好適な値に抑制される。
【０１６１】
また、本実施例によれば、補正中止判定手段３６０により、前記運転者の要求する要求駆動力Ｆ_T1すなわちその要求駆動力Ｆ_T1に対応するアクセル開度θ_A が零でない所定値θ_A2以上となったと判定された場合には、道路勾配に対応した駆動力ｄＦの付与が中止されるものであることから、要求駆動力Ｆ_T1すなわちその要求駆動力Ｆ_T1に対応するアクセル開度θ_A が零から所定値θ_A2までの範囲内であるときには、道路勾配が大きくなるのに対応して大きくなる駆動力が付与され、車両の後退（ずり落ち）が好適に防止される。
【０１６２】
図３２は、ハイブリッド制御装置１０４による車両の駆動力制御の他の制御機能の要部を説明する機能ブロック線図である。図３２において、目標駆動力算出手段３８０は、たとえば図３３に示す予め記憶された関係から実際の運転者による出力操作手段の操作程度たとえばアクセルペダル１２２の操作量（アクセル開度）θ_A と車速Ｖとに基づいて目標駆動力すなわち目標駆動トルクＴ_T を決定する。上記図３３に示す関係は、運転者の要求駆動力或いは要求加速力を実現するために予め実験的に求められたものである。後輪分配比低減係数算出手段３８２は、たとえば図３４に示す予め記憶された関係から上記目標駆動力算出手段３８０により求められた目標駆動トルクＴ_T に基づいて後輪分配比低減係数Ｋ_creep を算出する。この図３４に示す関係は、目標駆動力が小さい場合にはＲＭＧ７０の作動を可及的に少なくする図３５の特性を得るために予め実験的に求められたものである。理想後輪分配比算出手段３８４は、たとえば前記図１２のＳＣ４にて用いられている関係式から荷重配分に基づく前後輪の理想駆動力配分を実現するための理想後輪分配比Ｋ_tro を算出する。車両発進判定手段３８６は、車両が発進状態であるか否かをアクセル開度θ_A および車速などに基づいて判定する。後輪分配比算出手段３８８は、車両発進判定手段３８６により車両の発進状態が判定されると、上記後輪分配比低減係数算出手段３８２により求められた後輪分配比低減係数Ｋ_creep と上記理想後輪分配比算出手段３８４により求められた理想後輪分配比Ｋ_tro とを乗算することにより、後輪分配比Ｋ_trを算出する。前輪駆動力算出手段３９０は、上記目標駆動トルクＴ_T および後輪分配比Ｋ_trから前輪駆動力（前輪駆動トルク）Ｔ_F （＝Ｔ_T ×（１−Ｋ_tr））を算出し、後輪駆動力算出手段３９２は、上記目標駆動トルクＴ_T および後輪分配比Ｋ_trから後輪駆動力（後輪駆動トルク）Ｔ_R （＝Ｔ_T ×Ｋ_tr）を算出する。原動機駆動制御手段３９４は、上記前輪駆動力算出手段３９０により算出された前輪駆動力（前輪駆動トルク）Ｔ_F が得られるようにその前輪６６、６８を駆動するエンジン１４およびＭＧ１６を制御するとともに、上記後輪駆動力算出手段３９２により算出された後輪駆動力（後輪駆動トルク）Ｔ_R が得られるようにその後輪８０、８２を駆動するＲＭＧ７０を制御して４輪駆動走行を行う。
【０１６３】
図３５は、上記目標（要求）駆動力Ｔ_T 、前輪駆動力Ｔ_F 、後輪駆動力（後輪駆動トルク）Ｔ_R との関係を示している。後輪分配比低減係数Ｋ_creep を求めるための図３４に示す関係では、目標駆動力Ｔ_T が所定値Ｆ₁ に到達するまでは後輪分配比低減係数Ｋ_creep が零であるとその所定値Ｆ₁ からそれよりも大きい所定値Ｆ₂ までの間は目標駆動力Ｔ_T が増加するにともなって後輪分配比低減係数Ｋ_creep が比例的に増加し、所定値Ｆ₂ を越えると後輪分配比低減係数Ｋ_creep が飽和して増加しないように設定されている。この所定値Ｆ₂ は、凍結路、圧雪路などの低摩擦係数（μ）路において前輪６６、６８や後輪８０、８２がスリップしない駆動力の上限値（最大値）に基づいてそれに対応するように決定されている。したがって、目標駆動力Ｔ_T が所定値Ｆ₂ を越えると理想的な配分比で前輪６６、６８や後輪８０、８２から駆動力が出力され、その所定値Ｆ₂ 以下からクリープまでにおいては前後トルク配分比を前輪側に多く、後輪側に少なくされる。図３５は、理想後輪配分比Ｋ_tro が０．５であるときの特性を示している。
【０１６４】
図３６は、図３２の実施例におけるハイブリッド制御装置１０４の駆動力制御作動を説明するフローチャートである。図３６において、ＳＦ１では、アクセル開度θ_A 、車速Ｖなどの入力信号が読み込まれる。次いで、前記目標駆動力算出手段３８０に対応するＳＦ２では、たとえば図３３に示す予め記憶された関係から実際のアクセル開度θ_A と車速Ｖとに基づいて運転者の要求駆動力に対応する目標駆動力すなわち目標駆動トルクＴ_T が決定される。次に、前記理想後輪分配比算出手段３８４に対応するＳＦ３において、たとえば前記図１２のＳＣ４にて用いられている関係式から荷重配分に基づく前後輪の理想駆動力配分を実現するための理想後輪分配比Ｋ_tro が算出される。そして、前記車両発進判定手段３８６に対応するＳＦ４において車両の発進状態であるか否かが判断される。このＳＦ４の判断が否定される場合は、前輪６６、６８による２輪駆動とするためにＳＦ５において後輪分配比低減係数Ｋ_creep の内容が「０」に設定される。
【０１６５】
しかし、上記ＳＦ４の判断が肯定される場合は、前輪６６、６８および後輪８０、８２による４輪駆動とするために、前記後輪分配比低減係数算出手段３８２に対応するＳＦ６において、たとえば図３４に示す予め記憶された関係からＳＦ２により求められた目標駆動トルクＴ_T に基づいて後輪分配比低減係数Ｋ_creep が算出される。続いて、前記後輪分配比算出手段３８８に対応するＳＦ７では、上記理想後輪分配比Ｋ_tro に後輪分配比低減係数Ｋ_creep を掛けることによって後輪分配比Ｋ_trが算出される。次いで、前記後輪駆動力算出手段３９２に対応するＳＦ８では、上記目標駆動トルクＴ_T および後輪分配比Ｋ_trから後輪駆動力（後輪駆動トルク）Ｔ_R （＝Ｔ_T ×Ｋ_tr）が算出される。次に、前記前輪駆動力算出手段３９０に対応するＳＦ９では、上記目標駆動トルクＴ_T および後輪分配比Ｋ_trから前輪駆動力（前輪駆動トルク）Ｔ_F （＝Ｔ_T ×（１−Ｋ_tr））が算出される。そして、原動機駆動制御手段３９４に対応するＳＦ１０では、上記ＳＦ９により算出された前輪駆動力（前輪駆動トルク）Ｔ_F が得られるようにその前輪６６、６８を駆動するエンジン１４およびＭＧ１６が制御されるとともに、上記ＳＦ８により算出された後輪駆動力（後輪駆動トルク）Ｔ_R が得られるようにその後輪８０、８２を駆動するＲＭＧ７０が制御されて４輪駆動走行が行われる。これにより、図３５に示すように、目標駆動力が所定値Ｆ₂ よりも小さい場合にはＲＭＧ７０の作動が可及的に少なくされ、その消費電力、熱損失が小さくされてその使用域が拡大される。
【０１６６】
上述のように、本実施例によれば、４輪駆動車の制御装置において、たとえば図１３、図２５、或いは図３３に示す予め記憶された関係から実際の運転者による出力操作手段の操作程度すなわちアクセル開度θ_A と車速Ｖとに基づいて求められた目標駆動力Ｆ_T （目標駆動トルクＴ_T ）を前輪側および後輪側から出力させるために、車両状態（図１５および段落０１０７の後輪荷重分担比）、車両の運転状態（図１１および段落００９３の前後輪回転速度差、図２３および段落０１３７、０１３８の前後Ｇセンサ）、或いは道路状態（図２３および段落０１３８、０１３９の路面μおよび道路勾配）に基づいて前輪駆動力および後輪駆動力が制御されるので、運転者が要求している目標駆動力Ｆ_T を得るために、車両状態、車両の運転状態、或いは道路状態が適切に反映された４輪駆動が可能となる。
【０１６７】
また、本実施例によれば、第１原動機は、複数の動力源、さらに詳しくは複数の相互に形式が異なる動力源すなわちエンジン１４およびＭＧ１６から成る複合原動機であるので、それを構成する動力源の１つであるエンジン１４がその効率の高い領域で作動させられ得るので、燃費が高められる。
【０１６８】
また、本実施例によれば、第２原動機は、１個または２個以上の電動機或いは発電機能を備えたモータジェネレータから構成され得、本実施例では１個のＲＭＧ７０から成るものであり、４輪駆動車の後輪８０、８２を駆動するものであるので、前輪駆動状態と４輪駆動状態との間で切換られる。
【０１６９】
また、本実施例の４輪駆動車の制御装置は、前後輪間の駆動力配分に対応する理想後輪分配比Ｋ_tro を目標駆動力Ｔ_T に基づいて変更するものである。たとえば、目標駆動力Ｔ_T が所定値Ｆ₂ を下まわるとき目標駆動力Ｔ_T に基づいて決定された後輪分配比低減係数Ｋ_creep をその後輪分配比Ｋ_tro に乗算することにより変更するものであるので、駆動力が小さい場合には可及的にＲＭＧ７０の作動が抑制され、その温度上昇が回避されるようになっている。
【０１７０】
また、本実施例では、車両の発進状態であるときにおいて前後輪間の駆動力配分が目標駆動力Ｔ_T に基づいて変更されるので、４輪駆動車の発進時における前後輪間の駆動力配分が目標駆動力Ｔ_T に基づいて適切に変更される利点がある。
【０１７１】
また、本実施例では、車両の発進状態であるときにおいて、前後輪の駆動力配分比に対応する理想後輪分配比Ｋ_tro が、目標駆動力Ｔ_T が所定値Ｆ₂ 以上であるときよりも、所定値Ｆ₂ 未満のときは第１原動機および第２原動機のうちの熱的に不利な方の原動機により駆動される車輪（本実施例ではＲＭＧ７０により駆動される後輪８０、８２）の分配比を小さくするように変更されるものであることから、第１原動機および第２原動機のうちの熱的に不利な方の熱的負荷が軽減されるので、４輪駆動の継続が一層可能となる。
【０１７２】
また、本実施例では、車両の発進状態であるときに、前後輪の駆動力配分比が、目標駆動力Ｔ_T が所定値Ｆ₂ 以上であるときよりも、所定値Ｆ₂ 未満のときは第２原動機により駆動される車輪側である後輪分配比Ｋ_trを小さくするように変更されることから、ＲＭＧ７０から出力される駆動力が小さくされるので、ＲＭＧ７０の温度上昇が抑制され、その使用範囲が拡大される。
【０１７３】
また、本実施例では、駆動力配分比に対応する目標後輪分配比Ｋ_tro を変更するための所定値Ｆ₂ は、所定の低摩擦係数路面で駆動輪がスリップに至らない最大駆動力から決定されたものであることから、駆動輪がスリップに至らない所定値Ｆ₂ 以下の目標駆動力範囲内において駆動力配分比に対応する目標後輪分配比Ｋ_tro が変更されて第２原動機に対応するＲＭＧ７０の出力が小さくされ、その過熱が好適に防止される。
【０１７４】
また、本実施例の４輪駆動車の制御装置において、車両の運転状態が発進状態（図９のＳＡ２）、加速状態（図９のＳＡ６、ＳＡ７）、低摩擦係数路面走行状態（図９のＳＡ１、ＳＡ３）のうちのいずれかの状態である場合は前輪および後輪を駆動する４輪駆動とされ、いずれでもない場合は前輪および後輪の一方を駆動する２輪駆動とされることから、発進状態、加速状態、低摩擦係数路面走行状態のうちのいずれかの状態である場合は自動的に前輪および後輪を駆動する４輪駆動とされるので、運転状態に応じて不要な４輪駆動が回避され、４輪駆動とするために作動させられる第２原動機の過熱が好適に防止される。
【０１７５】
また、本実施例の４輪駆動車の制御装置は、車両の軽負荷走行中、すなわち減速走行中、ブレーキ操作のない非加速走行中である場合は４輪駆動とする（図９のＳＡ８）ものであるので、軽負荷走行時に自動的に４輪駆動に切り換えられる。
【０１７６】
また、本実施例の第１原動機および第２原動機は回生制御可能な動力源すなわちＭＧ１６、ＲＭＧ７０を含むものであり、その第１原動機はエンジン１４を含むものであるので、エンジン１４が効率のよい領域で作動させられるように電動機として機能するＭＧ１６或いはＲＭＧ７０から駆動力が発生させられ得る。
【０１７７】
また、本実施例では、車両の発進時には、前記第１原動機または第２原動機に含まれる電動機のみ或いはエネルギ回生可能な電動機として機能するＭＧ１６或いはＲＭＧ７０のみにより車輪が駆動される場合があるものである（図５、図９のＳＡ２）ことから、エンジン１４が非作動状態で発進させられるので、車両の燃費が改善される。
【０１７８】
また、本実施例では、車両の制動時または惰行走行時は、電動機および発電機として機能するＭＧ１６或いはＲＭＧ７０を用いた回生制御を行うものであるので、エネルギ回生率が向上して車両の燃費が改善される。
【０１７９】
また、本実施例では、所定以上の負荷時に第１原動機はエンジン１４のみにより車輪を駆動するか、エンジン１４およびエネルギ回生可能な動力源或いは電動機として機能するＭＧ１６により車輪を駆動するものであるので、４輪駆動車において十分な駆動力が確保される。
【０１８０】
以上、本発明の実施例を図面に基づいて詳細に説明したが、本発明はその他の態様においても適用される。
【０１８１】
たとえば、前述の実施例の車両は、前輪６６、６８をエンジン１４およびＭＧ１６を備えた主駆動装置１０が駆動し、後輪８０、８２をＲＭＧ７０を備えた副駆動装置１２が駆動する前後輪駆動（４輪駆動）形式であったが、逆に前輪６６、６８をＲＭＧ７０を備えた副駆動装置１２が駆動し、後輪８０、８２をエンジン１４およびＭＧ１６を備えた主駆動装置１０が駆動してもよい。またその原動機はエンジン、電動機、および油圧モータなどの少なくとも１つから構成されたものであってもよい。
【０１８２】
また、前述の実施例では、複数種類の制御例が説明されていたが、それらの制御例は所定の車両において相互に適宜組み合わせて実施され得るものである。
【０１８３】
また、前述の実施例では、前輪６６、６８および後輪８０、８２はそれぞれ別の原動機により駆動されていたが、共通の原動機により駆動される４輪駆動車であってもよい。この場合、前輪および後輪は共通の原動機に作動的に連結されるとともに、その原動機から出力された駆動力の前輪および後輪への駆動力配分比は、駆動力配分クラッチによって変化させられるものである。このような４輪駆動車の制御装置においても、前述と同様に、運転者の出力操作手段の操作程度（アクセル開度θ_A ）と車速Ｖとに基づき目標駆動力Ｔ_T を求め、その目標駆動力Ｔ_T を基に前輪側および後輪側から出力すべき駆動力を車両状態に基づき制御することができる。この場合でも、運転者が要求している駆動力を得るために、車両状態が適切に反映された４輪駆動が可能となる。
【０１８４】
また、前述の実施例では、補正駆動力発生手段３５５により登坂発進のための補正駆動力ｄＦが予め求められ、目標駆動力Ｆ_T1に対応する車両の駆動力に補正駆動力ｄＦを付与するために補正駆動力付与手段３５６によりその補正駆動力ｄＦが目標駆動力Ｆ_T1に加算されていたが、登坂発進のための補正係数（１より大）が予め求められ、目標駆動力Ｆ₁ に対応する車両の駆動力にその補正係数を付与するためにその補正係数が目標駆動力Ｆ₁ に乗算されるようにしてもよい。
【０１８５】
また、前述の実施例の原動機駆動力制御手段３６６では、上記補正駆動力ｄＦをＲＭＧ７０により駆動される後輪８０、８２から出力させていたが、エンジン１４或いはＭＧ１６に駆動される前輪６６、６８から出力させてもよいし、４輪駆動状態であるときには、そのときの駆動力配分比を変化させないようにＲＭＧ７０により駆動される後輪８０、８２およびエンジン１４或いはＭＧ１６に駆動される前輪６６、６８から出力させてもよい。
【０１８６】
また、前述の実施例の車両は、その動力伝達経路に無段変速機２０を備えたものであったが、遊星歯車式或いは常時噛み合い型平行２軸式の有段変速機を備えたものであってもよい。
【０１８７】
また、前述の実施例では、ハイブリッド制御装置１０４により図２９、図３０に示す車両の駆動力制御が行われていたが、他の制御装置により実行されても差し支えない。
【０１８８】
以上、本発明の実施例を図面に基づいて詳細に説明したが、これはあくまでも一実施形態であり、本発明は当業者の知識に基づいて種々の変更，改良を加えた態様で実施することができる。
【図面の簡単な説明】
【図１】本発明の一実施例の制御装置を備えた４輪駆動車両の動力伝達装置の構成を説明する骨子図である。
【図２】図１の遊星歯車装置を制御する油圧制御回路の要部を説明する図である。
【図３】図１の４輪駆動車両に設けられた制御装置を説明する図である。
【図４】図３のエンジン制御装置により制御されるエンジンの運転点の目標である最良燃費率曲線を示す図である。
【図５】図３のハイブリッド制御装置により選択される制御モードを示す図表である。
【図６】図３のハイブリッド制御装置により制御されるＥＴＣモードにおける遊星歯車装置の作動を説明する共線図である。
【図７】図３のハイブリッド制御装置などの制御機能の要部を説明する機能ブロック線図である。
【図８】図７の出力トルク領域記憶手段において記憶された複数種類の出力トルク領域を示す図である。
【図９】図３のハイブリッド制御装置などの制御作動の要部を説明するフローチャートであって、出力トルク領域切換および後輪切換制御ルーチンを示す図である。
【図１０】図３のハイブリッド制御装置などの制御作動の要部を説明するフローチャートであって、４輪駆動中止制御ルーチンを示す図である。
【図１１】図３のハイブリッド制御装置などの制御機能の要部を説明する機能ブロック線図である。
【図１２】図３のハイブリッド制御装置などの制御作動の要部を説明するフローチャートであって、出力トルク領域切換および後輪切換制御ルーチンを示す図である。
【図１３】図１１の第２原動機作動制御手段において、運転者要求トルクを算出するための予め記憶された関係を示す図である。
【図１４】図１２の制御作動を説明するタイムチャートである。
【図１５】図３のハイブリッド制御装置などの制御機能の要部を説明する機能ブロック線図である。
【図１６】図１または図３のＭＧ或いはＲＭＧの温度をパラメータとする出力トルク領域を示す図である。
【図１７】図３の蓄電装置における受入制限値ＷINおよび持出制限値ＷOUT の温度特性を示す図である。
【図１８】図３のハイブリッド制御装置などの制御作動の要部を説明するフローチャートである。
【図１９】図１８のＳＤ２のエンジン指令トルク算出ルーチンを示す図である。
【図２０】図１８のＳＤ３のＲＭＧ出力トルク仮決定ルーチンを示す図である。
【図２１】図１８のＳＤ４のＭＧ出力トルク決定ルーチンを示す図である。
【図２２】図１８のＳＤ８のＲＭＧ出力トルク再計算ルーチンを示す図である。
【図２３】図９のフローチャートの他の例を示す図である。
【図２４】図３のハイブリッド制御装置などの制御機能の他の要部を説明する機能ブロック線図である。
【図２５】図２４の目標出力決定手段により目標駆動力を決定するために用いられる予め記憶された関係を示す図である。
【図２６】図２４の仮補正駆動力決定手段により仮補正駆動力を決定するために用いられる予め記憶された関係を示す図である。
【図２７】図２４の補正駆動力発生手段により補正駆動力を発生させるために用いられる予め記憶された関係を示す図である。
【図２８】図２４の補正開始不可判定手段において補正開始不可を判定するための判断基準値を決定するために用いられる予め記憶された関係を示す図である。
【図２９】図２４のハイブリッド制御装置の制御作動の要部を説明するフローチャートであって、駆動力制御ルーチンを示している。
【図３０】図２４のハイブリッド制御装置の制御作動の要部を説明するフローチャートであって、登坂発進補正駆動力算出ルーチンを示している。
【図３１】図２４のハイブリッド制御装置の制御作動の要部である、路面傾斜角（停車時前後加速度Ｇ_xstpの変化に対する後退力の変化を説明する図である。
【図３２】図３のハイブリッド制御装置による他の駆動制御機能の要部を説明する機能ブロック線図である。
【図３３】図３２の目標駆動力算出手段により目標駆動力を算出するための用いられる予め記憶された関係を示す図である。
【図３４】図３２の後輪分配比低減係数算出手段いより後輪分配比低減係数を算出するための用いられる予め記憶された関係を示す図である。
【図３５】図３２の目標駆動力算出手段により目標駆動力、前輪駆動力算出手段により算出された前輪駆動力、後輪駆動力算出手段により算出された後輪駆動力の相対関係を説明する図である。
【図３６】図３２のハイブリッド制御装置による駆動力制御作動を説明するフローチャートである。
【符号の説明】
１４：エンジン（第１原動機）
６６、６８：前輪
７０：リヤモータジェネレータ（第２原動機）
８０、８２：後輪
３４８：目標出力決定手段
３５０：坂路発進アシスト制御手段
３５２：勾配検出手段
３５４：仮補正駆動力決定手段
３５５：補正駆動力発生手段
３５６：補正駆動力付与手段[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a control device for a four-wheel drive vehicle, and in particular, by changing the drive force distribution ratio of the front and rear wheels according to the target drive force when starting the vehicle, the drive of the rear wheel drive motor is reduced as much as possible to increase the temperature. It is to suppress.
[0002]
[Prior art]
In a four-wheel drive vehicle in which the front wheels are driven by an engine that functions as a first prime mover and the rear wheels are driven by an electric motor that functions as a second prime mover, the output torque of the motor with respect to the engine output torque according to the accelerator opening There is known a control device for increasing the value. For example, this is a four-wheel drive vehicle with an electric motor described in JP-A-63-188528.
[0003]
[Problems to be solved by the invention]
In the conventional four-wheel drive vehicle, the output of the electric motor is controlled based on the accelerator pedal and the vehicle speed so that the output of the electric motor is increased as the accelerator opening is larger. However, there is still room for improvement in the four-wheel drive running in which the outputs of the engine that drives the front wheels and the electric motor that drives the rear wheels are controlled according to the driving state. For example, when the target driving force targeted for the driver's required driving force is output from the front wheels and the rear wheels, if the vehicle state, the driving state of the vehicle, or the road state changes, an inappropriate driving force distribution ratio will result. This will result in sufficient four-wheel drive.
[0004]
The present invention has been made against the background of the above circumstances, and its object is to change the front and rear wheels with an appropriate driving force distribution ratio corresponding to changes in the vehicle state, the driving state of the vehicle, or the road state. It is to provide a control device for a four-wheel drive vehicle capable of obtaining a target driving force by driving the vehicle.
[0005]
[First Means for Solving the Problems]
  In order to achieve this object, the gist of the present invention is that a control device for a four-wheel drive vehicle in which one of the front wheels and the rear wheels can be driven by the first prime mover and the other can be driven by the second prime mover. Obtaining the target driving force based on the degree of operation of the output operation means by the driver and the vehicle speed, the front wheel driving force and the rear wheel driving force for outputting the target driving force from the front wheel side and the rear wheel side, the vehicle state, Control based on the driving state of the vehicle or road conditionsIn addition, the driving force distribution between the front and rear wheels is changed based on the target driving force.There is.
[0006]
[Effect of the first invention]
  In this way, in order to output the target driving force obtained based on the degree of operation of the output operation means by the driver and the vehicle speed from the front wheel side and the rear wheel side, the vehicle state, the driving state of the vehicle, or the road Since the front wheel driving force and the rear wheel driving force are controlled based on the state, the vehicle state, the driving state of the vehicle, or the road state is appropriately reflected in order to obtain the driving force requested by the driver. Four-wheel drive with a force distribution ratio is possible.In addition, since the driving force distribution between the front and rear wheels is changed based on the target driving force, for example, the target driving force is changed when the target driving force falls below a predetermined value. For example, the rear wheel driving force is reduced, and unnecessary power consumption and temperature rise of the rear wheel driving motor can be suitably prevented.
[0007]
[Other aspects of the first invention]
Here, preferably, the target driving force is calculated based on an actual accelerator opening and vehicle speed from a previously stored relationship, and the load sharing ratio (vehicle state) of the front and rear wheels, the front and rear wheel rotational speed difference, and the front and rear acceleration. The driving force output from the front and rear wheels is controlled based on (driving state), road surface friction coefficient, and road surface gradient (road state).
[0008]
Preferably, the first prime mover is a composite prime mover composed of a plurality of power sources, more specifically, a plurality of power sources having different types. In this way, in the composite prime mover, at least one of the power sources constituting the composite prime mover can be operated in a region where the efficiency is high, so that fuel efficiency is improved.
[0009]
Preferably, the second prime mover is composed of one or two or more motors or a motor generator having a power generation function. This second prime mover preferably drives the rear wheel of the front and rear wheels of the four-wheel drive vehicle.
[0011]
Preferably, the vehicle state is a start state of the vehicle, and the drive force distribution between the front and rear wheels is changed based on the target drive force when the vehicle starts. In this way, the driving force distribution between the front and rear wheels at the start of the four-wheel drive vehicle is appropriately changed based on the target driving force.
[0012]
Preferably, the vehicle state is a start state of the vehicle, and when the vehicle starts, the driving force distribution ratio of the front and rear wheels is less than a predetermined value than when the target driving force is a predetermined value or more. Is changed to reduce the distribution ratio of the wheels driven by the thermally disadvantageous prime mover of the first prime mover and the second prime mover. In this way, the thermal load of the first prime mover and the second prime mover, which is thermally disadvantageous, is reduced, so that the four-wheel drive can be further continued.
[0013]
Preferably, the vehicle state is a start state of the vehicle, and when the vehicle starts, the driving force distribution ratio of the front and rear wheels is less than a predetermined value than when the target driving force is a predetermined value or more. Is changed to reduce the distribution ratio on the wheel side driven by the second prime mover. In this way, since the driving force output from the second prime mover is reduced, the temperature rise of the second prime mover is suppressed and the use range is expanded.
[0014]
Preferably, the predetermined value for changing the driving force distribution ratio is determined from a maximum driving force at which a driving wheel does not slip on a predetermined low friction coefficient road surface. In this way, the driving force distribution ratio is changed within a target driving force range below a predetermined value at which the driving wheel does not slip, and the output of the second prime mover, that is, the rear wheel driving motor is reduced, and the overheating is preferable. To be prevented.
[0015]
[Second means for solving the problem]
The gist of the second invention for achieving the above object is a control apparatus for a four-wheel drive vehicle in which one of a front wheel and a rear wheel can be driven by a first prime mover and the other can be driven by a second prime mover. When the driving state of the vehicle is one of the start state, the acceleration state, and the low friction coefficient road surface driving state, the vehicle is set to four-wheel drive for driving the front wheels and the rear wheels. One of them is a two-wheel drive.
[0016]
[Effect of the second invention]
In this way, when the vehicle is in one of the starting state, the acceleration state, and the low friction coefficient road surface traveling state, it is a four-wheel drive that drives the front wheels and the rear wheels, so it is unnecessary depending on the driving state. 4 wheel drive is avoided, and overheating of the second prime mover that is operated to achieve four wheel drive is suitably prevented.
[0017]
[Other aspects of the second invention]
Here, preferably, the control device for the four-wheel drive vehicle is a four-wheel drive when the vehicle is traveling under a light load, that is, during deceleration traveling, or during non-acceleration traveling without a brake operation. If it does in this way, it will change to four-wheel drive at the time of light load running.
[0018]
Preferably, the first prime mover and the second prime mover include a power source capable of regenerative control, that is, an electric motor (motor generator), and the first prime mover includes an engine. In this way, driving force can be generated from the electric motor so that the engine can be operated in an efficient region.
[0019]
Preferably, when the vehicle starts, the wheel may be driven only by the electric motor included in the first prime mover or the second prime mover or only by the electric motor capable of regenerating energy. In this way, since the engine is started in a non-operating state, the fuel efficiency of the vehicle is improved.
[0020]
Preferably, when the vehicle is braked or coasting, regenerative control is performed using the motor as a generator. If it does in this way, an energy regeneration rate will improve and the fuel consumption of a vehicle will be improved.
[0021]
Preferably, the first prime mover drives the wheel only by the engine when the load exceeds a predetermined value, or drives the wheel by a power source or an electric motor capable of regenerating energy. In this way, sufficient driving force is secured in the four-wheel drive vehicle.
[0022]
[Third Means for Solving the Problems]
The gist of the third invention for achieving the above object is that in the control device for a four-wheel drive vehicle in which the front wheels and the rear wheels can be driven by the prime mover, the degree of operation of the output operation means of the driver and the vehicle speed. Based on the target driving force, the driving force to be output from the front wheel side and the rear wheel side is controlled based on the vehicle state.
[0023]
[Effect of the third invention]
In this way, in order to output the target driving force determined based on the degree of operation of the output operation means by the driver and the vehicle speed from the front wheel side and the rear wheel side, the front wheel driving force and the rear wheel driving force are determined based on the vehicle state. Since the wheel driving force is controlled, it is possible to perform four-wheel driving in which the vehicle state is appropriately reflected in order to obtain the driving force requested by the driver.
[0024]
[Other aspects of the third invention]
Here, the front wheels and the rear wheels are operatively connected to a common prime mover, and the drive force distribution ratio of the drive force output from the prime mover to the front wheels and the rear wheels is changed by the drive force distribution clutch. It is. In this way, it becomes unnecessary to provide prime movers at a plurality of locations.
[0025]
Another aspect of the present invention is that a first prime mover that drives one of the front wheels and the rear wheels, a second prime mover that drives the other wheel, and a slip ratio of the one wheel is a target of the one wheel. A control device for a front and rear wheel drive vehicle provided with a traction control means for reducing the driving force of one wheel so as to be within a slip ratio region, wherein (a) the actual slip state between the front and rear wheels is between the front and rear wheels. Torque distribution feedback control means for controlling the torque distribution of the front wheels and the rear wheels so as to achieve the target slip state; and (b) the torque distribution feedback control during execution and non-execution of the traction control by the traction control means. And feedback control operation changing means for changing the feedback control operation by the means. In this way, the torque distribution feedback control means feedback-controls the torque distribution of the front wheels and the rear wheels so that the actual slip state between the front and rear wheels becomes the target slip state between the front and rear wheels. The torque distribution is appropriate for the front and rear wheels. Further, since the feedback control operation by the torque distribution feedback control means is changed between the execution and non-execution of the traction control by the feedback control operation changing means, the feedback motor is driven by the first prime mover by executing the traction control. Even if the driving force is suppressed in order to reduce the slip of the wheel, the control operation amount for the second prime mover is ensured and the power performance of the vehicle is obtained.
[0026]
Preferably, a second prime mover operation control means for operating the second prime mover based on the torque distribution output from the torque distribution feedback control means is provided. In this way, when the second prime mover is operated, the vehicle torque distribution for setting the actual slip ratio to the target slip ratio is achieved.
[0027]
Preferably, the feedback control operation changing means includes a control deviation value of feedback control by the torque distribution feedback control means or a control target value for calculating the control deviation value during execution of the traction control, and At least one of the actual values is changed so as to increase the torque sharing ratio of the other wheel driven by the second prime mover. In this way, at least one of the control deviation value of the torque distribution feedback control means or the control target value for calculating the control deviation value and the actual value is the torque sharing of the other wheel driven by the second prime mover. Since the rate is changed so as to increase, the amount of control operation for the second prime mover is ensured even during execution of traction control by the traction control means, and the power performance of the vehicle is obtained.
[0028]
Preferably, the feedback control operation changing means is configured to increase a feedback gain of a feedback control type used by the torque distribution feedback control means to the other wheel driven by the second prime mover during execution of the traction control. The torque sharing rate is changed to increase. In this way, the feedback gain target of the torque distribution feedback control means is changed so as to increase the torque sharing rate of the other wheel driven by the second prime mover, so that the traction control means is executing traction control. In this case, the control operation amount for the second prime mover is ensured, and the power performance of the vehicle is obtained.
[0029]
Preferably, the feedback control operation changing means is driven by the second prime mover with a control output value obtained from a feedback control equation used by the torque distribution feedback control means during execution of the traction control. The torque sharing ratio of the other wheel is changed to increase. In this way, the control output value obtained from the feedback control equation is changed so as to increase the torque sharing ratio of the other wheel driven by the second prime mover, so that the traction control means is executing the traction control. In this case, the control operation amount for the second prime mover is ensured, and the power performance of the vehicle is obtained.
[0030]
Preferably, the traction control is to reduce the output of the first prime mover and / or the driving force of one of the vehicles when starting on a low μ road such as a snowy road or a freezing road. In this way, during the traction control in which the output of the first prime mover and / or the braking force of one wheel is controlled, the operation of the feedback control by the torque distribution feedback control means is changed.
[0031]
Another aspect of the present invention is a front and rear wheel drive vehicle including a first electric motor for driving front wheels and a second electric motor for driving rear wheels, the first electric motor and The second motor has a specific relationship between the thermal ratings of the second motor. In this way, since the correlation between the thermal ratings of the first motor and the second motor is in a specific state, the front and rear wheel drive vehicle can be considered in consideration of its driving force balance, and traveling Stability can be maintained.
[0032]
Preferably, the thermal rating of the first electric motor is higher than the thermal rating of the second electric motor. In this way, since the thermal rating of the second motor that drives the rear wheels is lower than the thermal rating of the first motor that drives the front wheels, the output of the second motor on the rear wheel side is limited first. Since it is a rear wheel, there is an advantage that the stability of the vehicle is relatively maintained.
[0033]
Another aspect of the invention is a control device for a front and rear wheel drive vehicle including a first electric motor for driving the front wheels and a second electric motor for driving the rear wheels. The second motor has a first motor operation increasing means for increasing the operation of the first motor when the operation of the motor is limited. In this way, when the operation of the second electric motor for driving the rear wheels is restricted, the operation of the first electric motor for driving the front wheels is increased. Therefore, while maintaining the stability of the vehicle relatively, Driving force or regenerative braking force is ensured. For example, when the output of the second motor is limited, the output of the first motor is increased so as not to change the total driving force of the vehicle, and when the regeneration of the second motor is limited, the total regenerative braking force of the vehicle is not changed. Further, the regeneration of the first electric motor is increased, so that the stability of the vehicle is maintained and the full driving force or the regenerative braking force of the vehicle is ensured.
[0034]
Preferably, the thermal rating of the first electric motor is higher than the thermal rating of the second electric motor. In this way, since the thermal rating of the second motor that drives the rear wheels is lower than the thermal rating of the first motor that drives the front wheels, the output of the second motor on the rear wheel side is limited first. Since it is a rear wheel, there is an advantage that the stability of the vehicle is relatively maintained.
[0035]
Another aspect of the invention is a control device for a front and rear wheel drive vehicle including a first electric motor for driving a front wheel and a second electric motor for driving a rear wheel. When the operation limit of one motor is limited, there is provided a second motor output reduction means for reducing the operation of the second motor in order to set the distribution ratio of the driving force or braking force of the front and rear wheels to a predetermined target distribution ratio. is there. In this way, when the operation of the first electric motor for driving the front wheels is limited, the operation of the second electric motor for driving the rear wheels is reduced, so that the driving force distribution ratio or the braking force distribution ratio of the front and rear wheels is reduced. Is set to a predetermined target distribution ratio, so that the stability of the vehicle is ensured. For example, when the output of the first motor is limited, the output of the second motor is reduced so that the rear wheel torque sharing ratio is maintained or the front wheel drive side (FF side) is maintained. Similarly, when the regeneration of the electric motor is limited, the regeneration of the second electric motor is reduced, so that the vehicle's stability is maintained and the full driving force or regenerative braking force of the vehicle is secured.
[0036]
Preferably, the thermal rating of the first electric motor is higher than the thermal rating of the second electric motor. In this way, since the thermal rating of the second motor that drives the rear wheels is lower than the thermal rating of the first motor that drives the front wheels, the output of the second motor on the rear wheel side is limited first. Since it is a rear wheel, there is an advantage that the stability of the vehicle is relatively maintained.
[0037]
Another aspect of the present invention is to provide a vehicle drive control device that applies driving force to driving wheels corresponding to a road gradient at the time of starting, when the driving force is applied corresponding to the road gradient. The driving force is set so that the vehicle speed is less than a predetermined vehicle speed greater than zero. In this way, when the driving force is applied corresponding to the road gradient at the start of the vehicle, the driving force of the vehicle, that is, the prime mover is set so that the reverse vehicle speed is less than or equal to a predetermined vehicle speed greater than zero. When the vehicle starts off the slope, the vehicle is slightly retracted at a predetermined vehicle speed or less before the accelerator pedal is depressed, so that the vehicle can be prevented from slipping down and the driver can know the road gradient accurately. For this reason, the driver can step on the vehicle according to the slope when starting the vehicle.
[0038]
Another aspect of the invention is that in a vehicle drive control device that applies driving force to drive wheels in response to a road gradient when starting, a non-operation duration time of a brake pedal is longer than a predetermined value while the vehicle is stopped. If it is long, the application of the driving force corresponding to the road gradient is stopped. In this way, when the non-operation duration of the brake pedal is longer than the predetermined value while the vehicle is stopped, the application of the driving force corresponding to the road gradient is stopped. Since the sliding is allowed, the driver can be informed of the degree of road gradient.
[0039]
Another aspect of the invention is that in a vehicle drive control device that applies driving force to driving wheels in response to a road gradient at the time of starting, the application of driving force corresponding to the road gradient is promptly performed at the start of execution. The driving force is increased, and the driving force is gradually decreased when the application of the driving force corresponding to the road gradient is stopped or ended. In this way, the driving force is quickly increased when driving force is applied to the driving wheel corresponding to the road gradient at the start, and the driving force is gently decreased when the driving force corresponding to the road gradient is stopped. Therefore, it is possible to quickly suppress the slippage when starting on the uphill road, and to stop applying the driving force without feeling uncomfortable.
[0040]
Another aspect of the invention is a control device for a four-wheel drive vehicle in which one of the front wheels and the rear wheels can be driven by the first prime mover and the other can be driven by the second prime mover. The target driving force is obtained based on the degree of operation of the operating means and the vehicle speed, and the driving force to be output from the front wheel side and the rear wheel side based on the target driving force is controlled based on the road gradient when the vehicle starts. It is to have done. In this way, the target driving force is obtained based on the degree of operation of the output operation means of the driver and the vehicle speed, and the driving force to be output from the front wheel side and the rear wheel side is determined based on the target driving force. Since the vehicle is controlled on the basis of the road gradient at the time, the target driving force that meets the driver's request is appropriately obtained, and the driving force distribution of the front and rear wheels that matches that at the start of the gradient starts.
[0041]
Preferably, the vehicle drive control device according to the present invention sets the driving force of the vehicle corresponding to the road gradient so that the reverse vehicle speed is less than or equal to the predetermined vehicle speed within a predetermined road gradient range. In this way, when the road gradient exceeds the predetermined road gradient, the driving force of the vehicle set so that the reverse vehicle speed is less than or equal to the predetermined vehicle speed cannot be further increased. Can be known more accurately.
[0042]
Preferably, the predetermined vehicle speed is several kilometer. For example, the vehicle speed is 1 to 3 km / h. In this way, the downhill road is suppressed to a suitable value.
[0043]
Preferably, in each of the above inventions, when the required driving force requested by the driver is not less than a predetermined value that is not zero, the application of the driving force corresponding to the road gradient is stopped. In this way, when the required driving force is within a range from zero to a predetermined value, a driving force that increases in response to an increase in the road gradient is applied, and the vehicle is preferably moved backward (slid down). Is prevented.
[0044]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0045]
FIG. 1 is a skeleton diagram illustrating a configuration of a power transmission device for a four-wheel drive vehicle, that is, a front-rear wheel drive vehicle to which a drive control device according to an embodiment of the present invention is applied. In this front and rear wheel drive vehicle, a front wheel system is driven by a first drive device having a first prime mover, that is, a main drive device 10, and a rear wheel system is driven by a second drive device having a second prime mover, that is, a sub drive device 12. It is a vehicle of the type which drives.
[0046]
The main drive device 10 includes an engine 14 that is an internal combustion engine that is operated by burning a mixture of air and fuel, and a motor generator (hereinafter referred to as MG) 16 that selectively functions as an electric motor and a generator. And a double pinion type planetary gear unit 18 and a continuously variable transmission 20 whose gear ratio is continuously changed. The engine 14 functions as a first prime mover, that is, a main prime mover, and the MG 16 also functions as a prime mover that is a drive source of the vehicle. The engine 14 includes a throttle actuator 21 that drives the throttle valve in order to change the opening degree θTH of the throttle valve that controls the intake air amount of the intake pipe.
[0047]
The planetary gear unit 18 is a combining / distributing mechanism that mechanically combines or distributes force, and includes three rotating elements provided so as to be independently rotatable around a common axis, that is, a damper to the engine 14. A sun gear 24 connected via the device 22, a carrier 28 connected to the input shaft 26 of the continuously variable transmission 20 via the first clutch C1 and to the output shaft of the MG 16, and a second clutch C2. And a ring gear 32 that is connected to the input shaft 26 of the continuously variable transmission 20 and connected to a non-rotating member such as the housing 30 via the brake B1. The carrier 28 supports a pair of pinions (planetary gears) 34 and 36 which mesh with the sun gear 24 and the ring gear 32 and mesh with each other so as to be able to rotate. The first clutch C1, the second clutch C2, and the brake B1 are hydraulically engaged when a plurality of overlapping friction plates are pressed by a hydraulic actuator or released by releasing the pressure. This is a friction engagement device.
[0048]
The MG 16 connected to the planetary gear unit 18 and its carrier 28 controls the power generation amount of the MG 16 in the operating state of the engine 14, that is, the rotational state of the sun gear 24, that is, the reaction force that is the rotational driving torque of the MG 16 increases sequentially. As described above, the electric torque converter (ETC) device that smoothly increases the number of rotations of the ring gear 32 and enables smooth start acceleration of the vehicle is configured. At this time, if the gear ratio ρ of the planetary gear unit 18 (the number of teeth of the sun gear 24 / the number of teeth of the ring gear 32) is 0.5, which is a general value, for example, the torque of the ring gear 32: the torque of the carrier 28: the sun gear 24 Torque = 1 / ρ: (1-ρ) / ρ: 1, the torque of the engine 14 is amplified to 1 / ρ times, for example, 2 times, and transmitted to the continuously variable transmission 20. It is called.
[0049]
The continuously variable transmission 20 is wound around a pair of variable pulleys 40 and 42 having variable effective diameters provided on the input shaft 26 and the output shaft 38, respectively, and the pair of variable pulleys 40 and 42. And an endless annular transmission belt 44. The pair of variable pulleys 40 and 42 are input so as to form a V-groove between the fixed rotating bodies 46 and 48 fixed to the input shaft 26 and the output shaft 38, respectively, and the fixed rotating bodies 46 and 48. Movable rotating bodies 50 and 52 that are movable in the axial direction with respect to the shaft 26 and the output shaft 38 and that are not relatively rotatable around the axis, and a variable pulley by applying thrust to the movable rotating bodies 50 and 52 And a pair of hydraulic cylinders 54 and 56 that change the transmission gear ratio γ (= input shaft rotational speed / output shaft rotational speed) by changing the engagement diameter of 40 and 42, that is, the effective diameter.
[0050]
The torque output from the output shaft 38 of the continuously variable transmission 20 is transmitted to the pair of front wheels 66 and 68 via the speed reducer 58, the differential gear device 60, and the pair of axles 62 and 64. It has become. In the present embodiment, a steering device that changes the steering angle of the front wheels 66 and 68 is omitted.
[0051]
The sub-drive device 12 includes a rear motor generator (hereinafter referred to as RMG) 70 that functions as a second prime mover, that is, a sub prime mover, and torque output from the RMG 70 is reduced by a speed reducer 72, a differential gear device 74, and 1 It is transmitted to a pair of rear wheels 80 and 82 via a pair of axles 76 and 78.
[0052]
FIG. 2 is a diagram simply showing the configuration of a hydraulic control circuit for switching the planetary gear unit 18 of the main drive unit 10 to various operation modes. The manual valve 92 mechanically connected to the shift lever 90 that is operated to the P, R, N, D, and B range positions by the driver responds to the operation of the shift lever 90 while using the shuttle valve 93. Then, in the D range, the B range, and the R range, the original pressure output from the oil pump (not shown) is supplied to the first pressure regulating valve 94 that regulates the engagement pressure of the first clutch C1. The original pressure is supplied to the second pressure regulating valve 95 that regulates the engagement pressure of C2, and the original pressure is supplied to the third pressure regulating valve 96 that regulates the engagement pressure of the brake B1 in the N range, the P range, and the R range. The second pressure regulating valve 95 and the third pressure regulating valve 96 control the engagement pressure of the second clutch C2 and the brake B1 in accordance with the output signal from the linear solenoid valve 97 driven by the hybrid control device 104, and the first pressure regulating valve 94. Controls the engagement pressure of the first clutch C <b> 1 according to an output signal from the electromagnetic on-off valve 98 that is a three-way valve that is duty-driven by the hybrid control device 104.
[0053]
FIG. 3 is a diagram illustrating a configuration of a control device provided in the front and rear wheel drive vehicle of the present embodiment. The engine control device 100, the shift control device 102, the hybrid control device 104, the power storage control device 106, and the brake control device 108 are so-called microcomputers having a CPU, a RAM, a ROM, and an input / output interface. While using the storage function, the input signal is processed in accordance with a program stored in advance in the ROM, and various controls are executed. Further, the above control devices are connected so as to be communicable with each other, and when a necessary signal is requested from a predetermined control device, it is appropriately transmitted from the other control device to the predetermined control device. ing.
[0054]
The engine control device 100 executes engine control of the engine 14. For example, a fuel injection valve (not shown) is controlled to control the fuel injection amount, an igniter (not shown) is controlled to control the ignition timing, and the traction control causes the front wheels 66 and 68 that are slipping to grip the road surface. The throttle actuator 21 is controlled in order to temporarily reduce the output.
[0055]
For example, the transmission control device 102 determines the actual transmission ratio γ and the transmission torque, that is, the engine 14 and the MG 16 from the relationship set in advance so that the tension of the transmission belt 44 of the continuously variable transmission 20 becomes a necessary and sufficient value. Based on the output torque, the pressure regulating valve that regulates the belt tension pressure is controlled so that the tension of the transmission belt 44 is set to an optimum value, and the engine 14 is operated in advance along the minimum fuel consumption rate curve or the optimum curve. From the stored relationship, the target speed ratio γm is determined based on the actual vehicle speed V and the engine load, for example, the throttle valve opening degree θTH expressed as the throttle opening degree θ or the accelerator pedal operation amount ACC. The speed ratio γ of the continuously variable transmission 20 is controlled so as to coincide with the target speed ratio γm.
[0056]
Further, the engine control device 100 and the shift control device 102 set the throttle actuator 21 and the fuel injection amount, for example, so that the operating point, that is, the operating point of the engine 14 moves along the best fuel consumption driving line shown in FIG. The speed ratio γ of the continuously variable transmission 20 is changed while being controlled. Further, in response to a command from the hybrid control device 104, the throttle actuator 21 and the gear ratio γ are changed to change the output torque TE or the rotational speed NE of the engine 14, and the operating point of the engine 14 is moved.
[0057]
The hybrid control device 104 includes an MG control device 116 for controlling an inverter 114 that controls a drive current supplied from the power storage device 112 made of a battery or the like to the MG 16 or a power generation current output from the MG 16 to the power storage device 112. And an RMG control device 120 for controlling an inverter 118 for controlling a drive current supplied from the power storage device 112 to the RMG 70 or a generated current output from the RMG 70 to the power storage device 112, and an operation position PSH of the shift lever 90 Based on the throttle (accelerator) opening θ (the amount of operation ACC of the accelerator pedal 122), the vehicle speed V, and the stored amount SOC of the power storage device 112, for example, one of a plurality of operation modes shown in FIG. As well as the throttle opening θ and the operation amount BF of the brake pedal 124. Based on this, a torque regenerative braking mode in which a braking force is generated by a torque required for power generation by the MG 16 or RMG 70 or an engine braking mode in which a braking force is generated by a rotational resistance torque of the engine 14 is selected.
[0058]
When the shift lever 90 is operated to the B range or the D range, for example, in a relatively low load start or constant speed travel, the motor travel mode is selected, the first clutch C1 is engaged, and the second clutch C2 and brake are engaged. When B1 is released together, the vehicle is driven exclusively by MG16. In this motor travel mode, when the state of charge SOC of the power storage device 112 falls below a preset lower limit, or when the engine 14 is started to require more driving force. The MG 16 or the RMG 70 is driven while being switched to an ETC mode or a direct connection mode, which will be described later, while maintaining the traveling so far, and the power storage device 112 is charged by the MG 16 or the RMG 70.
[0059]
Further, in the relatively medium load traveling or the high load traveling, the direct connection mode is selected, the first clutch C1 and the second clutch C2 are both engaged, and the brake B1 is released, so that the planetary gear unit 18 is integrated. The vehicle is driven exclusively by the engine 14 or by the engine 14 and the MG 16, or the vehicle is driven exclusively by the engine 14, and at the same time, the power storage device 112 is charged by the MG 16. In this direct connection mode, the rotational speed of the sun gear 24, that is, the engine rotational speed NE (rpm), the rotational speed of the carrier member 28, that is, the rotational speed NMG (rpm) of the MG 16, and the rotational speed of the ring gear 32, that is, the input shaft 26 of the continuously variable transmission 20. Since the rotation speed NIN (rpm) is the same value, the three rotation speed axes (vertical axis), that is, the sun gear rotation speed axis S, the ring gear rotation speed axis R, and the carrier rotation speed axis C in the two-dimensional plane In the collinear diagram of FIG. 6 drawn from the speed ratio axis (horizontal axis), for example, it is shown by a one-dot chain line. In FIG. 6, the distance between the sun gear rotational speed axis S and the carrier rotational speed axis C corresponds to 1, and the distance between the ring gear rotational speed R and the carrier rotational speed axis C is the gear of the double pinion type planetary gear unit 18. This corresponds to the ratio ρ.
[0060]
Further, for example, in starting acceleration running, the ETC mode, that is, the torque amplification mode is selected, the second clutch C2 is engaged, and both the first clutch C1 and the brake B1 are released, and the amount of power generation (regeneration amount) of the MG 16 That is, the reaction force of MG 16 (driving torque for rotating MG 16) is gradually increased, so that the vehicle is smoothly started to zero while engine 14 is maintained at a predetermined rotational speed. Thus, when the vehicle and MG 16 are driven by the engine 14, if the torque of the engine 14 is 1 / ρ times, for example, ρ = 0.5, it is amplified twice and transmitted to the continuously variable transmission 20. That is, when the rotational speed NMG of the MG 16 is the point A in FIG. 6 (negative rotational speed, that is, in the power generation state), the input shaft rotational speed NIN of the continuously variable transmission 20 is zero and the vehicle is stopped. However, as shown by the broken line in FIG. 6, the power generation amount of the MG 16 is increased and the rotational speed NMG is changed to the positive B point, so that the input shaft rotational speed of the continuously variable transmission 20 is increased. NIN is increased and the vehicle is started.
[0061]
When the shift lever 90 is operated to the N range or the P range, the neutral mode 1 or 2 is basically selected, the first clutch C1, the second clutch C2, and the brake B1 are all released, and the planetary gear unit 18 is released. The power transmission path is released at. In this state, when the storage amount SOC of the power storage device 112 is in an insufficiency state below a preset lower limit value, the charging / engine start mode is set and the brake B1 is engaged. The engine 14 is started by the MG 16. When the shift lever 90 is operated to the R range, for example, in the light load reverse travel, the motor travel mode is selected, the first clutch C1 is engaged, and the second clutch C2 and the brake B1 are both released, The vehicle is driven backward by MG16 exclusively. However, for example, in medium- or high-load reverse travel, the friction travel mode is selected, the first clutch C1 is engaged, the second clutch C2 is released, and the brake B1 is slip-engaged. Thereby, the output torque of the engine 14 is added to the output torque of the MG 16 as a driving force for moving the vehicle backward.
[0062]
Further, the hybrid control device 104 controls the RMG 70 according to a predetermined driving force distribution ratio in order to temporarily increase the driving force of the vehicle when the vehicle starts or suddenly accelerates according to the driving force of the front wheels 66 and 68. The start ability of the vehicle is increased when the vehicle starts driving on a high-μ road assist control that activates and generates driving force from the rear wheels 80 and 82, and on a low friction coefficient road (low μ road) such as a frozen road or a snowy road. In order to increase the speed, the rear wheels 80 and 82 are driven by the RMG 70, and at the same time, for example, the low μ road assist control is performed to reduce the driving force of the front wheels 66 and 68 by lowering the speed ratio γ of the continuously variable transmission 20.
[0063]
The power storage control device 106 charges or stores the power storage device 112 with the electric energy generated by the MG 16 or RMG 70 when the power storage amount SOC of the power storage device 112 such as a battery or a capacitor falls below a preset lower limit SOCD. However, when the charged amount SOC exceeds the preset upper limit value SOCU, charging with electric energy from the MG 16 or RMG 70 is prohibited. Further, during the above power storage, the range between the power or electrical energy acceptance limit value WIN and the take-out limit value WOUT as a function of the temperature TB of the power storage device 112 is set to the actual expected power value Pb [= generated power PMG + consumption. If the power PRMG (negative)] is exceeded, the acceptance or take-out is prohibited.
[0064]
The brake control device 108 executes, for example, TRC control, ABS control, VSC control, etc., in order to increase the stability of the vehicle during start running, braking, and turning on a low μ road, or to increase the traction force. Wheel brakes 66WB, 68WB, 80WB, 82WB provided on the wheels 66, 68, 80, 82 are controlled via a brake control circuit. For example, in TRC control, based on a signal from a wheel rotation (wheel speed) sensor provided on each wheel, wheel vehicle speed (body speed converted based on wheel rotation speed), for example, right front wheel wheel speed VFR, left front wheel wheel Vehicle speed VFL, right rear wheel speed VRR, left rear wheel speed VRL, front wheel speed [= (VFR + VFL) / 2], rear wheel speed [= (VRR + VRL) / 2], and vehicle body speed (VFR, VFL, VRR, While calculating (slowest speed of VRL), for example, a slip speed ΔV, which is a difference between the front wheel speed as the main driving wheel and the rear wheel speed as the non-driving wheel, is a preset control start determination reference value ΔV1. When the value exceeds, the throttle actuator 21 and the wheel brake 66WB are judged so that the front wheel slips and the slip ratio RS [= (ΔV / VF) × 100%] falls within the preset target slip ratio RS1. Reducing the driving force of the front wheels 66, 68 such as by using a 68WB. In the ABS control, the front brakes 66 and 68 and the rear wheels 80 and 82 are used by using the wheel brakes 66WB, 68WB, 80WB, and 82WB so that the slip ratio of each wheel is within a predetermined target slip range during the braking operation. Maintain braking force and improve vehicle directional stability. Further, in the VSC control, when the vehicle is turning, the vehicle oversteer is based on a steering angle from a steering angle sensor (not shown), a yaw rate from a yaw rate sensor, longitudinal acceleration and lateral (lateral) acceleration from a biaxial G sensor, and the like. A tendency or an understeer tendency is determined, and one of the wheel brakes 66WB, 68WB, 80WB, and 82WB and the throttle actuator 21 are controlled so as to suppress the oversteer or understeer.
[0065]
FIG. 7 is a functional block diagram illustrating the main part of the control function of the hybrid control device 104 and the like. In FIG. 7, the output torque area storage means 130 is provided, for example, in the RAM of the hybrid control device 104, and stores a plurality of types of output torque areas representing characteristics for limiting the output torque of the RMG 70. Yes. In this embodiment, as shown in FIG. 8, two-dimensional coordinates of the rotational speed shaft 132 representing the rotational speed NRMG of the RMG 70 and the output torque shaft 134 representing the output torque TRMG of the RMG 70 are included in the plurality of types of output torque regions. A plurality of types of regions set in the first output torque region where the maximum torque value indicated by the A1 line is relatively higher than the A2 line, that is, the region inside the A1 line, and the A2 line having a low torque value. The second output torque region where the maximum torque value indicated by is relatively lower than the A1 line, that is, the region inside the A2 line is included. The first output torque region represents, for example, the maximum rating (short-time rating such as a 5-minute rating) of the RMG 70, and the second output torque region represents a long-time rating such as a 30-minute rating. It is.
[0066]
The vehicle driving state determination means 136 includes vehicle start determination means 138 for determining whether or not the vehicle is starting based on the position of the shift lever 90, the accelerator opening θ, the vehicle speed V, and the like, and the right front wheel speed VFR, Wheel slip determination means 140 for determining the occurrence of slips on the front wheels 66 and 68, which are the main drive wheels, based on the left front wheel speed VFL, the right rear wheel speed VRR, and the left rear wheel speed VRL, the steering angle and Understeer determination means 142 for determining understeer in turning traveling of the vehicle based on the yaw rate, etc., turning determination means 144 for determining turning traveling of the vehicle based on the steering angle being larger than a predetermined value, and the accelerator opening Acceleration operation determination for determining acceleration operation of the vehicle based on the change rate dθ / dt, that is, the operation speed of the accelerator pedal 122 is equal to or higher than a predetermined value. Step 146, high load travel determination means 148 for determining high load travel of the vehicle based on the accelerator opening θ being equal to or greater than a predetermined value, and deceleration travel of the vehicle based on the accelerator travel θ and the vehicle speed V The vehicle is in a driving (running) state, that is, one of vehicle start-up running, wheel slip, understeer, turning, acceleration operation, high-load running, and deceleration running. Determine.
[0067]
The output torque region selection means 152 is configured to output one output torque from a plurality of types of output torque regions stored in advance in the output torque region storage means 130 based on the vehicle driving state, for example, whether or not there is vehicle start, wheel slip, or understeer. Select an area. The output torque region selection means 152 has a higher maximum torque value in the starting state of the vehicle, the slip state of the front wheels 66 and 68 driven by the engine 14, or the understeer state than in the case of such a vehicle state. Select the output torque area. That is, when any one of vehicle start, wheel slip, and understeer is determined by the vehicle operation state determination means 136, the first output torque region is selected, and turning, acceleration, high load, and deceleration are performed. If any one is determined, the second output torque region is selected. That is, the output torque region is selected in order to switch the degree of output torque of the RMG 70 that performs four-wheel drive in accordance with the driving state.
[0068]
The second prime mover operation control unit 154 operates the RMG 70 based on one output torque region selected by the output torque region selection unit 152 based on the driving state of the vehicle. The second prime mover operation control means 154 basically generates a driving force from the rear wheels 80 and 82 with a driving force distribution ratio corresponding to the static load distribution ratio or the dynamic load distribution ratio of the front and rear wheels. Thus, the RMG 70 is operated within the selected output torque region. That is, the RMG 70 is operated so as not to deviate from the selected output torque region, in other words, not to exceed the maximum torque value of the selected output torque region. The second prime mover operation control means 154 is the first torque selected by the output torque region selection means 152 in order to obtain a high four-wheel drive effect when the vehicle is in a vehicle start, wheel slip, or understeer state. When the RMG 70 is operated based on the output torque region and the vehicle state is any of turning, acceleration operation, high load traveling, and decelerating traveling, the output torque region selecting means is used to obtain a long four-wheel driving effect. RMG 70 is operated based on the second output torque region selected by 152.
[0069]
Further, the second prime mover operation control means 154 determines that the vehicle driving state determination means 136 does not determine any of the vehicle start running, the front wheels 66 and 68 slip, understeer, turning, acceleration operation, and high load running. Determines that the four-wheel drive is unnecessary, and stops the operation of the RMG 70 after a preset delay time in order to prevent the determination from flapping. .
[0070]
The second prime mover operation control means 154 is configured to output the first output when the output torque area selected by the output torque area selection means 152 is an output torque area having a maximum torque value lower than the maximum torque value of the output torque area so far. When the second output torque region is selected instead of the torque region, when the output torque region having the maximum torque value higher than the maximum torque value of the output torque region so far is selected, that is, in the second output torque region. Instead, as compared with the case where the first output torque region is selected, the output torque of the RMG 70 is gradually reduced to prevent the driving force of the rear wheels 80 and 82 from rapidly decreasing.
[0071]
The ABS control determining means 158 is configured to set the wheel slip ratio within a preset slip ratio range during execution of the ABS control by the brake control device 108, that is, during braking operation of the vehicle using a signal from the wheel speed sensor. It is determined whether or not the control for controlling the braking force of each wheel is being executed. The VSC control determination means 160 determines the braking force of the left and right wheels or the driving force of the wheels so that the vehicle body direction does not deviate from the steering angle of the steering wheel during execution of the VSC control by the brake control device 108, that is, during turning of the vehicle. It is determined whether or not the control is under execution to prevent understeer or oversteer. The wheel speed sensor abnormality determining means 164 determines the abnormality of the wheel speed sensor based on the relative values of the right front wheel speed VFR, the left front wheel speed VFL, the right rear wheel speed VRR, and the left rear wheel speed VRL. . The low temperature state determination means 162 determines whether or not a low temperature state in which the outside air temperature detected by a temperature sensor (not shown) falls below a preset determination reference value, such as a temperature state where road surface freezing can occur. The steering angle sensor abnormality determining means 166 determines abnormality of the steering angle sensor for detecting the steering angle of the steering wheel used for VSC control. The yaw rate sensor abnormality determining means 168 determines an abnormality of the yaw rate sensor for detecting the yaw rate used for the VSC control.
[0072]
The second prime mover operation control means 154 performs VSC control when the wheel speed sensor abnormality is determined by the wheel speed sensor abnormality determination means 164, when the ABS control determination means 158 determines the ABS control operation, or when the VSC control determination means 160 performs VSC control. At the time of operation determination, the operation of the RMG 70 is stopped even if the four-wheel drive operation condition is established and executed. In addition, when the low temperature state determination unit 162 determines that the second prime mover operation control unit 154 is in the low temperature state, the second prime mover operation control unit 154 preferentially operates the RMG 70 to be in the four-wheel drive state. Further, the second prime mover operation control means 154 determines that the steering angle sensor abnormality is determined by the steering angle sensor abnormality determination means 166 or the yaw rate sensor abnormality determination means 168 determines that the yaw rate sensor is abnormal. Even if understeer is determined by the understeer determination means 142, the RMG 70 is not operated and four-wheel drive is not started.
[0073]
FIGS. 9 and 10 are flowcharts for explaining a main part of the control operation of the hybrid control device 104 and the like. FIG. 9 shows an output torque region switching routine for switching the output torque region of the RMG 70 that performs four-wheel drive. FIG. 10 shows a four-wheel drive stop routine for stopping or prohibiting the four-wheel drive at the time of abnormality or control interference.
[0074]
In the output torque region switching and rear wheel switching control routine of FIG. 9, it is determined in SA1 corresponding to the low temperature state determination means 162 whether or not the outside air temperature is a low temperature state that can cause a change in the road surface friction coefficient. . If the determination of SA1 is affirmative, the 4WD unnecessary counter is reset in SA16, and the maximum torque value is indicated by the A1 line as the output torque region of the RMG 70 in SA17 corresponding to the output torque region selection means 152. The first output torque region is selected. Next, in SA18 corresponding to the second prime mover operation control means 154, the RMG 70 is operated in the first output torque region in order to execute four-wheel drive.
[0075]
If the determination in SA1 is negative, whether or not the vehicle is in a starting state in SA2 corresponding to the vehicle start determination means 138 is based on the position of the shift lever 90, the throttle opening θ, the vehicle speed V, and the like. Is judged. If the determination at SA2 is affirmative, SA16 and subsequent steps are executed, and RMG 70 is operated within the first output torque region in order to execute four-wheel drive. However, if the determination in SA2 is negative, it is determined in SA3 corresponding to the wheel slip determination means 140 whether or not slip has occurred in the front wheels 66 and 68 that are the main drive wheels driven by the engine 14. Is done. If the determination at SA3 is affirmative, it is determined at SA14 whether the slip ratio of the front wheels 66, 68 is greater than a predetermined value. This predetermined value is for determining the degree of slip corresponding to the switching of the output torque region. If the determination at SA14 is affirmative, SA16 and subsequent steps are executed, and the RMG 70 is operated in the first output torque region in order to execute four-wheel drive. If the determination at SA14 is negative, SA19 In step SA20, the 4WD unnecessary counter is reset, and in SA20, it is determined whether or not the current use point of the RMG 70, that is, the operating point shown in the two-dimensional diagram of FIG. If the determination at SA20 is negative, the second output torque region is selected at SA21. If the determination is affirmative, at SA22, the second output torque region is selected from the first output torque region to gradually decrease the output torque of RMG 70. The output torque region is gradually changed from the A1 line to the A2 line. In the present embodiment, SA20 to SA22 also correspond to the output torque region selection means 152.
[0076]
If the determination in SA3 is negative, in SA4 corresponding to the understeer determination means 142, it is determined whether or not understeer has occurred based on the steering angle, the front / rear left / right biaxial acceleration, the yaw rate, and the like. If the determination at SA4 is affirmative, it is determined at SA15 whether or not the understeer is greater than or equal to a predetermined value. This predetermined value is for determining the degree of understeer corresponding to the switching of the output torque region. If the determination at SA15 is affirmative, SA16 and subsequent steps are executed, and the RMG 70 is operated within the first output torque region in order to execute four-wheel drive. However, if the determination at SA15 is negative, SA19 and subsequent steps are executed, and RMG 70 is operated in the second output torque region in order to execute four-wheel drive.
[0077]
If the determination at SA4 is negative, it is determined at SA5 corresponding to the turning travel determination means 144 whether the steering angle of the steering wheel is greater than a predetermined value. This predetermined value is a value for determining a steering angle that requires four-wheel drive. If the determination in SA5 is negative, it is determined in SA6 corresponding to the acceleration operation determination means 146 whether or not the accelerator required driving force, that is, the rate of change dθ / dt of the throttle opening is greater than a predetermined value. . This predetermined value is also a value for determining the rate of change in throttle opening that requires four-wheel drive. If the determination at SA6 is negative, it is determined at SA7 corresponding to the high load travel determination means 148 whether the throttle opening θ is larger than a predetermined value. This predetermined value is also a value for determining the throttle opening degree θ that requires four-wheel drive. If the determination in SA7 is negative, in SA8 corresponding to the deceleration travel determination means 150, whether the vehicle is decelerating, that is, whether it is non-accelerated travel without brake operation, is the operation position of the shift lever 90, throttle opening. The determination is made based on the degree θ, the vehicle speed V, and the like.
[0078]
When any of the determinations of SA5 to SA8 is affirmed, the RMG 70 is operated in the second output torque region in order to execute the four-wheel drive by executing the SA19 and the subsequent steps. However, if all of the determinations of SA1 to SA8 are negative, that is, the vehicle is not in a low temperature state, the vehicle is not starting, the front wheels 66 and 68 do not slip and understeer, the vehicle is not turning, and the acceleration request operation If the vehicle is not traveling at a high load or decelerating, after the 4WD counter is incremented in SA9, it is determined in SA10 whether or not the content of the 4WD counter has exceeded a predetermined value of about several seconds. . This 4WD counter is for counting the elapsed time since the determination of SA8 is denied, and the predetermined value prevents flutter when switching from the four-wheel drive state to the two-wheel (FF) drive state. It corresponds to the delay time set to do.
[0079]
Since the determination of SA10 is initially denied, SA20 and subsequent steps are executed. At this time, when the first output torque region is selected and the operating point of the RMG 70 is at a position of the A2 line or higher, the first output torque region is gradually changed from the first output torque region to the first output torque region. If selected and the RMG 70 operating point is below the A2 line, the first output torque region is immediately switched to the second output torque region and maintained if the second output torque region is selected. .
[0080]
If the contents of the 4WD counter become the predetermined value or more and the determination of SA10 is affirmed while the above steps are repeatedly executed, whether the current driving state of the vehicle is the two-wheel (FF) driving state in SA11. It is determined whether or not. If the determination of SA11 is negative, in SA12 corresponding to the second prime mover operation control means 154, the driving force of the RMG 70 is gradually decreased toward zero, so that the two wheels (FF ) It is gradually changed to the driving state. However, if the determination at SA11 is affirmative, the two-wheel (FF) drive state is maintained.
[0081]
In the four-wheel drive stop control routine of FIG. 10, in SB1 corresponding to the wheel speed sensor abnormality determining means 164, it is determined whether any of the wheel speed sensors provided for each wheel is abnormal. When the determination of SB1 is negative, it is determined whether or not the ABS control is determined in SB2 corresponding to the ABS control determination means 158. When the determination of SB2 is negative, it is determined whether or not VSC control is being determined in SB3 corresponding to the VSC control determination means 160. If any of the determinations in SB1 to SB3 is affirmed, the four-wheel drive operation, that is, the operation of the RMG 70 is stopped or prohibited in SB4 corresponding to the second prime mover operation control means 154.
[0082]
However, if any of the determinations of SB1 to SB3 is negative, it is determined whether or not the steering angle sensor is abnormal in SB5 corresponding to the steering angle sensor abnormality determination means 166, and the determination of SB5 is negative. If so, it is determined in SB6 corresponding to the yaw rate sensor abnormality determining means 168 whether or not the yaw rate sensor is abnormal. When either of the above determinations of SB5 and SB6 is affirmed, the four-wheel drive operation, that is, the operation of the RMG 70 is stopped or prohibited in SB7 corresponding to the second prime mover operation control means 154. However, if both the determinations of SB5 and SB6 are negative, this routine is terminated.
[0083]
As described above, according to the present embodiment, the second prime mover operation control means 154 (SA18) determines the vehicle from a plurality of types of output torque areas stored by the output torque area selection means 152 (SA17, SA21, SA22). Since the RMG 70 is operated based on one output torque region selected based on the driving state, the RMG 70 is operated within a necessary and sufficient output torque range corresponding to the driving state of the vehicle. The use of the RMG 70 below is less restricted, and the running performance of the vehicle as a four-wheel drive can be obtained as much as possible.
[0084]
Further, according to the present embodiment, the plurality of types of output torque regions stored in the output torque region storage means 130 are the rotational speed shaft 132 representing the rotational speed NRMG of the RMG 70 and the output torque shaft representing the output torque TRMG of the RMG 70. A plurality of types of regions set within two-dimensional coordinates with the first output torque region having a relatively high maximum torque value and a relatively low first torque value as shown in FIG. 2 output torque regions are included, depending on the necessity of four-wheel drive, the first output torque region having a relatively high maximum torque value and the second output torque region having a relatively low maximum torque value are Since a necessary and sufficient output torque region can be selected according to the driving state or the traveling state, the normal operation in the first output torque region where the maximum torque value is high is prevented, and R The operation of the G70 is ensured.
[0085]
Further, according to this embodiment, the second prime mover operation control means 154 (SA18) is configured so that the output torque area selected by the output torque area selection means 152 (SA17, SA21, SA22) is greater than the maximum torque value so far. If the second output torque region is selected instead of the first output torque region, the output torque region selected by the output torque region selecting means 152 is the output torque region up to that point. The output torque of the RMG 70 is gradually reduced as compared with the case where the output torque region has a maximum torque value higher than the maximum torque value, that is, when the first output torque region is selected instead of the second output torque region. Therefore, it is driven by the MG 70 when the second output torque region is selected instead of the first output torque region. Rapid decrease of the driving force of the wheels 80, 82 is prevented, the stability of the vehicle behavior is improved.
[0086]
Further, according to the present embodiment, when the second prime mover operation control means 154 (SA12) switches from the four-wheel drive state to the two-wheel drive state in which the RMG 70 is not operated, the output torque of the RMG 70 is gradually reduced toward zero. Alternatively, the driving force of the rear wheels 80 and 82 at the time of switching from the four-wheel driving state to the two-wheel driving state is prevented, and the stability of the vehicle behavior is improved.
[0087]
Further, according to the present embodiment, the output torque region selection means 152 (SA17, SA21, SA22) is in a state where the vehicle is started, the front wheels 66 and 68 driven by the engine 14 have a large slip, or the understeer is large. Then, since the first output torque region having a maximum maximum torque value is selected as compared with the case where the vehicle state is not such, the vehicle starting state, the front wheels 66 and 68 driven by the engine 14 are selected. When the slip is large or the understeer is large, the driving force of the rear wheels 80 and 82 driven by the RMG 70 can be sufficiently increased, so that the RMG 70 can be operated according to the degree of necessity of four-wheel drive. As a result, a sufficient driving force can be obtained at the start and the generated slippage of the front wheels 66 and 68 can be eliminated. At the same time eliminating the understeer of the vehicle it can be suitably obtained, is as much as possible overheating of RMG70 suppression, there is an advantage that its use opportunity is enlarged.
[0088]
Further, according to the present embodiment, the wheel slip sensor abnormality determining means 164 (SB1) for determining abnormality of each wheel speed sensor and a signal from each wheel speed sensor are used to slip the wheel during the braking operation of the vehicle. ABS control determining means 158 (SB2) for determining ABS control for controlling the braking force of the wheel so that the ratio falls within a preset slip ratio range, and the vehicle body direction from the steering angle of the steering wheel during turning of the vehicle VSC control determination means 162 (SB3) for determining VSC control for preventing understeer or oversteer by controlling the braking force of the left and right wheels or the driving force of the wheels so as not to deviate, and the second prime mover operation control means 154 (SA12) is when the wheel speed sensor is abnormal or when the ABS control determining means 158 or the VSC control determining means 160 When the operation of the ABS control or the VSC control is determined, the operation of the RMG 70 is stopped. Therefore, when the wheel speed sensor is abnormal or when the ABS control means or the VSC control means is operated, the front wheels 66, 68 are automatically activated. Therefore, the ABS control or VSC control abnormality caused by any abnormality of the wheel vehicle speeds VFR, VFL, VRR, VRL is avoided, or the control interference is prevented and the safety is improved. .
[0089]
Further, according to the present embodiment, the low temperature state determination means 162 (SA1) is provided for determining a low temperature state in which the outside air temperature is below a predetermined temperature at which a change in the friction coefficient of the traveling road surface is predicted. 2 The prime mover operation control means 154 (SA17) operates the RMG 70 preferentially based on the first output torque region when the low temperature state is determined by the low temperature state determination means 162. In this state, the RMG 70 is automatically operated to enter the four-wheel drive state, so that the stability of the vehicle is ensured.
[0090]
In addition, according to the present embodiment, vehicle start determination means 138 (SA2) for determining whether or not the vehicle is starting running, and wheel slip determination for determining occurrence of slip of the front wheels 66 and 68 that are the main drive wheels. Means 140 (SA3), understeer determination means 142 (SA4) for determining understeer in turning traveling of the vehicle based on the steering angle and yaw rate, and turning traveling determination means 144 (determining that the steering angle is larger than a predetermined value) SA5), acceleration operation determination means 146 (SA6) for determining an acceleration operation based on the accelerator pedal operation speed, that is, dθ / dt being equal to or greater than a predetermined value, and the accelerator pedal operation amount, that is, the throttle opening θ, is a predetermined value. High load travel determination means 148 (SA7) for determining the high load travel as described above, and deceleration travel determination for determining the deceleration travel of the vehicle Means 150 (SA8), and the second prime mover operation control means 154 determines that any one of vehicle start running, wheel slip, understeer, turning running, acceleration operation, and high load running is determined. Since it is determined that the wheel drive is necessary and the RMG 70 is operated, the second prime mover is automatically operated when the four-wheel drive is required, so that the stability of the vehicle is ensured.
[0091]
Further, according to the present embodiment, the second prime mover operation control means 154 determines that the four-wheel drive is not performed when none of the vehicle start-up traveling, wheel slip, understeer, turning traveling, acceleration operation, or high-load traveling is determined. Since it is determined that driving is not required and the operation of the RMG 70 is stopped after a preset delay time and the two-wheel drive state is set, the operation of the RMG 70 is reduced as much as possible to prevent overheating and 4 The fluttering of the determination is prevented by stopping the operation of the second prime mover after a predetermined delay time from the determination that the wheel drive is unnecessary.
[0092]
Further, according to the present embodiment, the steering angle sensor abnormality determining means 166 (SB5) that determines abnormality of the steering angle sensor that detects the steering angle of the steering wheel, or the yaw rate that determines abnormality of the yaw rate sensor that detects the yaw rate. The sensor abnormality determination means 168 (SB6) is provided, and the second prime mover operation control means 154 determines that the steering angle sensor abnormality is determined by the steering angle sensor abnormality determination means 166, or the yaw rate sensor abnormality determination means 168 determines the yaw rate. If a sensor abnormality is determined, the RMG 70 is not operated even if the understeer is determined by the understeer determination unit 142. If understeer is erroneously determined due to a steering angle sensor abnormality or a yaw rate sensor abnormality, four-wheel drive is performed. There are advantages not to be.
[0093]
FIG. 11 is a functional block diagram illustrating a main part of another control function provided in the hybrid control device 104 or the like. In FIG. 11, the 4WD start determining means 230 determines whether or not a start condition for the four-wheel drive state, that is, a condition for switching from the two-wheel drive state to the four-wheel drive state is satisfied, based on the driving state of the vehicle. . For example, it is determined that the four-wheel drive start condition is satisfied based on any one of vehicle start-up travel, wheel slip, understeer, turning travel, acceleration travel, high-load travel, and deceleration travel. The actual slip ratio calculating means 232 calculates the rotational speed NF of the front wheels 66 and 68 as the main driving wheels by calculating an average value of the rotational speed NFL of the left front wheel wheel 66 and the rotational speed NFR of the right front wheel wheel 68. The rotation speed N R of the rear wheels 80 and 82 as auxiliary driving wheels is calculated by obtaining the average value of the rotation speed N RL of the left rear wheel 80 and the rotation speed N RR of the right rear wheel 82, and the front wheels 66, The actual slip ratio S is obtained by dividing the difference between the rotational speed NF of 68 and the rotational speed NR of the rear wheels 80 and 82 (NF -NR) by the lower value of the front wheel rotational speed NF and the rear wheel rotational speed NR. [= 100% × (NF−NR) / min (NF, NR)] is sequentially calculated. In the target slip ratio setting means 234, a target slip ratio SO determined in advance to obtain a desired four-wheel drive is set and stored. The target slip ratio S0 may be a constant value, but may be a different value depending on the traveling state of the four-wheel drive.
[0094]
The torque distribution feedback control means 236 calculates a slip ratio deviation δsr1 (= S1−SO 1) between the actual slip ratio S and the target slip ratio S0, for example, using a preset feedback control formula shown in Formula 1. The rear wheel torque sharing ratio Rr, which is a control operation amount, is calculated so that the slip ratio deviation δsr1 is eliminated, that is, the actual slip ratio S and the target slip ratio SO 1 coincide. The rear wheel torque sharing ratio Rr is a ratio that the rear wheels 80 and 82 share in the driving force (driving torque) of the vehicle corresponding to the driver required torque when driving four wheels, and is a value smaller than 1. . Therefore, the front wheel torque sharing ratio is (1-Rr).
[0095]
(Formula 1)
Rr = WRr + Kp1 · δsr1 + Kd1 · dδsr1 / dt + Ki1 · ∫δsr1 dt + C1
Here, WRr is a rear wheel load sharing ratio, Kp1 is a proportional constant, that is, a proportional term gain, Kd1 is a differential constant, that is, a differential term gain, Ki1 is an integral constant, that is, an integral gain, and C1 is a constant.
[0096]
The second prime mover operation control means 238 achieves the torque distribution based on the torque distribution output from the torque distribution feedback control means 236, for example, the rear wheel torque sharing ratio Rr and the driver-requested driving force Tdrv. The RMG 70 is operated as follows. That is, the rear wheel torque (Tdrv × Rr) is calculated from the driver required torque Tdrv and the rear wheel torque sharing ratio Rr, and the RMG 70 is driven so that the rear wheel torque is output. The driver request torque Tdrv is calculated based on the vehicle speed V and the throttle opening θ from the relationship stored in advance as shown in FIG.
[0097]
The traction control in-progress determination unit 240 determines whether or not traction (TRC) control by the brake control device 108 is being executed. When the traction control determining unit 240 determines that the traction control is being performed, the feedback control operation changing unit 242 performs the feedback control operation by the torque distribution feedback control unit 236 by changing the rear wheel torque sharing ratio Rr, that is, the RMG 70. Preferably, the driving force is changed so that the driving force of the vehicle in the four-wheel drive state does not decrease, or the driver request torque Tdrv is substantially maintained so that the driving force increases as compared with the case of Formula 1.
[0098]
For example, the feedback control operation changing means 242 calculates the slip ratio deviation δsr1 (= S1−SO1) or the slip ratio deviation δsr1 which is the control deviation value of the feedback control expression of Formula 1 during traction control. At least one of the target slip ratio SO 1, which is the control target value, and the actual slip ratio S 1, which is the actual value, is the torque sharing ratio (rear wheel torque sharing ratio Rr), which is the output value of the control equation. It changes so that it may raise rather than the case of Numerical formula 1. For example, the slip ratio deviation δsr1 or the actual slip ratio S1 is increased by a predetermined value δsr2 or S2, or the target slip ratio SO1 is decreased by a predetermined value SO2 to be calculated by Equation 1. The rear wheel torque sharing ratio Rr is increased.
[0099]
Alternatively, the feedback control operation changing means 242 separately or in addition to the above, the feedback gains Kp1, Kd1, Ki1 of the feedback control formula used by the torque distribution feedback control means 236 during the execution of the traction control, RMG70 The torque sharing ratio (rear wheel torque sharing ratio Rr) of the rear wheels 80 and 82 driven by the above is changed so as to increase. For example, at least one of the feedback gains Kp1, Kd1, and Ki1 is updated to values Kp2, Kd2, and Ki2 that are larger than those by a predetermined value, and the constant C1 is changed to C2. The torque sharing ratio Rr is increased as compared with the case of Equation 1.
[0100]
Alternatively, the feedback control operation changing unit 242 may be a control output value obtained from the feedback control expression of Formula 1 used by the torque distribution feedback control unit 236 during the execution of the traction control separately or in addition to the above. A certain rear wheel torque sharing ratio Rr is sequentially changed by correcting it to an increase side by a predetermined value.
[0101]
FIG. 12 is a flowchart for explaining a main part of another control operation provided in the hybrid control device 104 or the like. In FIG. 12, in SC1 corresponding to the 4WD start determination means 230, it is determined based on the driving state of the vehicle whether or not the four-wheel drive start condition is satisfied. If the determination at SC1 is negative, after the rear wheel torque sharing ratio Rr is set to zero, at SC6 corresponding to the second prime mover operation control means 238, the driver's required driving torque Tdrv and the rear wheel The driving torque of the rear wheels 80 and 82 is calculated based on the torque sharing ratio Rr, and the driving torque is output from the RMG 70. In this case, since the rear wheel torque sharing ratio Rr is set to zero in the above SC2, the output torque of the RMG 70 is set to zero, and the two-wheel running is performed in which only the driving force of the front wheels 66 and 68 is run.
[0102]
However, if the determination at SC1 is affirmative, it is determined at SC3 corresponding to the traction control in-progress determination means 240 whether or not traction control by the brake control device 108 is being executed. If the determination in SC3 is negative, the slip ratio deviation δsr1 (= S1−SO1) between the actual slip ratio S and the target slip ratio S0 is calculated in SC4 corresponding to the torque distribution feedback control means 236, For example, the rear wheel torque sharing ratio Rr is calculated based on the actual slip ratio deviation δsr1 from the preset feedback control equation shown in Equation 1 so as to eliminate it. Next, in SC6 corresponding to the second prime mover operation control means 238, the driving torque (Tdrv × Rr) of the rear wheels 80 and 82 is calculated based on the driver's required driving torque Tdrv and the rear wheel torque sharing ratio Rr. The RMG 70 is driven so that the driving torque is output from the rear wheels 80 and 82.
[0103]
Since the determination of SC3 is affirmed during the traction control, the feedback control operation is performed so that the rear wheel torque sharing ratio Rr becomes larger in SC5 corresponding to the feedback control operation changing means 242 than in the case of SC4. Is changed. For example, the rear wheel torque sharing ratio Rr is calculated by using a feedback control equation in which the feedback gains Kp1, Kd1, Ki1 of Equation 1 are changed to values Kp2, Kd2, Ki2 that are larger than the feedback gains Kp1, Kd1, Ki1. In SC6, the driving torque (Tdrv × Rr) of the rear wheels 80 and 82 is calculated based on the driver's required driving torque Tdrv and the rear wheel torque sharing ratio Rr, and the driving torque is calculated from the rear wheels 80 and 82. The RMG 70 is driven so that it is output. Thereby, in order to ensure the driving force of the vehicle during the traction control, a driving torque larger than the case where Formula 1 is used is output from the rear wheels 80 and 82.
[0104]
Hereinafter, the operation of the present embodiment will be described with reference to the time chart of FIG. For example, if four-wheel drive running is started at time t1 due to a low μ road such as a frozen road, when the traction control is not executed, the front wheel rotational speed NF and the front wheels 66 and 68 are slipped as indicated by the solid line. The rear wheel torque sharing ratio Rr is increased as shown by the solid line in accordance with the feedback control equation of Equation 1 so that the actual slip ratio S changes and the driver required torque Tdrv is maintained. As the running continues, the slip of the front wheels 66 and 68 converges and the front wheel rotational speed NF decreases, so that the rear wheel torque sharing ratio Rr is reduced to an original value, for example, about 0.5. However, when the traction control is executed, the increase in the front wheel rotational speed NF and the actual slip ratio S is suppressed by the effect of the traction control. Therefore, when the feedback control expression of Expression 1 is used, the slip ratio deviation Since δsr1 (= S1−SO1) becomes small and the rear wheel torque sharing ratio Rr does not increase so much, the driving force of the entire vehicle becomes small and falls below the driver's required torque Tdrv, and the power performance of the vehicle cannot be obtained. It was. That is, when the torque distribution of the RMG 70 is adjusted by the feedback control operation by the torque distribution feedback control 236, the slip of the front wheels 66 and 68 driven by the engine 14 by the execution of the traction control is suppressed, and the actual slip ratio of the front and rear wheels is reduced. Since the control device 104 approaches the target value, the control device 104 reduces the output of the RMG 70, that is, the torque distribution to the rear wheels 80 and 82, as if the feedback control effect of the torque distribution is obtained. Will be reduced.
[0105]
However, according to the present embodiment, in the feedback control operation changing means 242 (SC5), for example, feedback obtained by changing the feedback gains Kp1, Kd1, Ki1 of Equation 1 to values Kp2, Kd2, Ki2 that are larger than the feedback gains Kp1, Kd1, Ki1. By using the control expression, the rear wheel torque sharing ratio Rr having a larger value than that in the case of the feedback control expression of Expression 1 is calculated, so that the feedback control operation is changed so that the torque sharing ratio Rr becomes a large value. Is done. For this reason, during the traction control, a larger driving torque than the case of Formula 1 is output from the rear wheels 80 and 82, and the power performance of the vehicle is ensured. FIG. 14 shows a case where the target slip ratio S02 is changed to be small by the feedback control operation changing means 242 for easy understanding. Even in this case, since the slip ratio deviation δsr2 (= S2−SO2) is obtained, the rear wheel torque distribution ratio Rr calculated by the feedback control equation is also increased, so that a large driving torque is generated from the rear wheels 80 and 82. It is output and the power performance of the vehicle is obtained. Even if the actual slip ratio S1 is changed to S2 larger than that, or the calculated slip ratio deviation δsr2 is corrected to be increased by a predetermined value, the same effect as described above can be obtained, and the feedback of Formula 1 can be obtained. Even if the rear wheel torque distribution ratio Rr, which is the control output value calculated by the control equation, is directly corrected to be increased by a predetermined value, the same effect as described above can be obtained.
[0106]
FIG. 15 is a functional block diagram illustrating a main part of another control function provided in the hybrid control device 104 or the like. In FIG. 15, in the four-wheel drive state, the first motor operation control means 330 calculates the front wheel drive torque corresponding to the front wheel torque share ratio (1-Ktr), which is the front wheel load share ratio of the driver required torque Tdrv. Then, the MG 16 is controlled so that the front wheel driving torque is output from the front wheels 66 and 68. For example, when the engine 14 and the MG 16 are simultaneously operated in the direct connection mode, the MG 16 is controlled so as to achieve the front wheel torque together with the output of the engine 14. In addition, the first motor operation control means 330 also has a front wheel torque sharing ratio (1-Ktr) of the required braking torque determined based on the amount of operation of the brake pedal 124, the amount of change in vehicle speed during coasting, and the like during braking. The front wheel regenerative torque corresponding to is calculated, and the MG 16 is controlled so that the front wheel regenerative torque is output from the front wheels 66 and 68.
[0107]
In the four-wheel drive state, the second motor operation control means 332 calculates a rear wheel drive torque corresponding to a rear load torque share ratio Ktr that is a rear wheel load share ratio of the driver required torque Tdrv, and then drives the rear wheel. The RMG 70 is controlled so that torque is output from the rear wheels 80 and 82. The second motor operation control means 332 also corresponds to the rear wheel torque sharing ratio Ktr in the required braking torque determined based on the operation amount of the brake pedal 124, the vehicle speed change amount during coasting, etc. even during braking. The rear wheel regeneration torque is calculated, and the RMG 70 is controlled so that the rear wheel regeneration torque is output from the rear wheels 80 and 82. The driver required torque Tdrv is determined based on the actual vehicle speed V and the throttle opening θ from the relationship stored in advance as shown in FIG. The front wheel load sharing ratio (1-Ktr) and the rear wheel torque sharing ratio Ktr are also target values, taking into account the static front / rear wheel load sharing ratio (constant value) or the vehicle's longitudinal acceleration (front / rear G). It is determined based on the dynamic front and rear wheel load sharing ratio (a function of front and rear G).
[0108]
The MG 16 and RMG 70 are restricted in use by their temperatures TMG and TRMG in order to ensure the insulation performance of the material that insulates the coil. For example, the MG 16 and RMG 70 are operated within the output torque range shown in FIG. Need to be done. When the temperature TMG of the MG 16 or the temperature TRMG of the RMG 70 is Ta degrees, it is operated within the region inside the maximum torque line indicated by T = Ta in FIG. 16, that is, within the range between the output limit value and the regeneration limit value. However, if it is Tc degrees, it must be operated in a small area inside the maximum torque line shown by T = Tc in FIG. In addition, the power storage device 112 is configured such that its output power or received power is limited by its temperature TB in order to prevent deterioration of its electrolyte, internal damage, or a decrease in its life. It is necessary to use within the range between the take-out limit value WOUT and the acceptance limit value WIN as shown in FIG.
[0109]
For this reason, the first motor operation limiting means 334 is, for example, an output limit value or a regeneration limit value determined by the temperature TMG of the MG 16 from the relationship of FIG. 16, or a take-out limit determined by the temperature TB of the power storage device 112 from the relationship of FIG. Based on the value WOUT and the acceptance limit value WIN, the drive operation or regenerative operation of the MG 16 is limited. Similarly, the second motor operation limiting means 336 is, for example, an output limit value or a regeneration limit value determined by the temperature TRMG of the RMG 70 from the relationship of FIG. 16, or a take-out limit determined by the temperature TB of the power storage device 112 from the relationship of FIG. Based on the value WOUT or the reception limit value WIN, the drive operation or regenerative operation of the RMG 70 is limited.
[0110]
When the driving operation or regenerative operation of the RMG 70 is restricted by the second motor operation restricting means 336, the first motor operation increasing means 338 is not changed in order to maintain the driving force or regenerative braking force of the entire vehicle. In addition, the drive output or regenerative output of the MG 16 is increased by an amount corresponding to the limit. Further, the second motor operation reducing means 340 is configured to maintain the torque sharing ratio of the front and rear wheels of the vehicle when the driving operation or the regenerative operation of the MG 16 is restricted by the first motor operation restriction means 334. The driving output or regenerative output of the RMG 70 is reduced by an amount corresponding to the limit in order to set the driving force distribution ratio or the braking force distribution ratio to a predetermined target distribution ratio.
[0111]
FIG. 18 is a flowchart for explaining a main part of another control operation of the hybrid control device 104, and shows a front and rear wheel torque distribution control routine in the direct running mode using the engine 14 and the MG 16. 18, in the pre-processing of SD1, the acceptance limit value WIN and the take-out limit value WOUT are calculated from the relationship of FIG. 17 based on the actual temperature TB of the power storage device 112, and from the relationship of FIG. The maximum allowable torque TMGmax and the minimum allowable torque TMGmin of the temperature-limited MG 16 are calculated based on this, and the maximum allowable torque TRMGmax and the minimum allowable torque TRMGmin of the temperature-limited RMG 70 are calculated based on the temperature TRMG of the RMG 70 from the relationship of FIG. Based on a signal from a rotation sensor (not shown), the rotation speed NMG of MG16, the rotation speed NMG of RMG 70, and the input shaft rotation speed NIN of the continuously variable transmission 20 are calculated, for example, from the relationship shown in FIG. The driver request torque Tdrv is calculated based on the vehicle speed V and the throttle opening θ, and the driver request torque Tdrv Torque, required engine output PV is calculated based like necessary charging torque. Here, the driver required torque Tdrv and the output or output torque described later include a negative value representing the regenerative braking force or torque, and the expression of increase or decrease thereof is based on their absolute values. Yes.
[0112]
Subsequently, in SD2, an engine command torque calculation routine of FIG. 19 is executed in order to calculate a command value of torque to be output to the engine 14. That is, in SD21, an engine output torque basic value TEbase (= PV / NE) for outputting to the engine 14 is calculated based on the required engine output PV and the engine speed NE. Next, in SD22, an upper limit value TEmax and a lower limit value “0” related to the engine 14 specification are added to the engine output torque basic value TEbase (0 ≦ TEbase ≦ TEmax), and the limited value is the engine value. The output torque command value TE is used. The engine 14 is controlled so that its output torque becomes the engine output torque command value TE.
[0113]
In the subsequent SD3, for example, the rear motor torque provisional determination routine shown in FIG. 20 is executed, whereby the output torque provisional determination value TRMGtmp of the RMG 70 is calculated. That is, in SD31 of FIG. 20, the upper limit value TRMGmaxp of the output torque of the RMG 70 is calculated based on the carry-out limit value WOUT. That is, PRMG is obtained from Equation 2 and Equation 3, and is used as the maximum output PRMGmaxp of the RMG 70. Next, TRMG satisfying Equation 4 is obtained from the PRMGmaxp and the rotational speed NRMG of the RMG 70, and this is set as the maximum output torque TRMGmaxp of the RMG 70. In Equation 3, EFMG is the efficiency of MG16, EFCVT is the efficiency of continuously variable transmission 20, and EFRMG is the efficiency of RMG70. In Equation 4, PRMGloss (NRMG, TRMG) is the power loss of the RMG 70.
[0114]

[0115]
In SD32, the lower limit value TRMGminp of the output torque of the RMG 70 is calculated based on the acceptance limit value WIN. That is, PRMG is obtained from Equation 5 and Equation 6, and is used as the minimum output PRMGminp of the RMG 70. Next, TRMG satisfying Expression 7 is obtained from the PRMGminp and the rotational speed NRMG of the RMG 70, and this is set as the minimum output torque TRMGminp of the RMG 70.
[0116]

[0117]
Subsequently, in SD33 corresponding to the second motor operation control means 332, the output torque basic value TRMGbase of the RMG 70 is calculated from Equation 8. The output torque basic value TRMGbase is a basic torque output from the RMG 70. In principle, the RMG 70 is driven so that this value is output. RMG 70 is driven so that is output. In Expression 8, GRR is a reduction ratio of the sub drive device 12 (the reduction device 72).
[0118]
(Formula 8)
TRMGbase = Tdrv × Ktr / GRR
[0119]
In SD34 corresponding to the second motor operation limiting means 336, the above-mentioned TRMGmaxp and TRMGminp for limiting the output torque basic value TRMGbase derived from the storage device 112 and the temperature derived from the temperature of the RMG 70. The upper and lower limit guard processing using TRMGmax and TRMGmin is executed according to Equation 9 and Equation 10, and the value after the upper and lower limit guard processing is determined as the output torque provisional determination value TRMGtmp of the RMG 70.
[0120]
(Formula 9)
TRMGminp ≤ TRMGbase ≤ TRMGmaxp
(Formula 10)
TRMGmin ≤ TRMGbase ≤ TRMGmax
[0121]
Returning to FIG. 18, in SD4, for example, the temporary torque determination routine TMGtmp of the MG 16 is calculated by executing the front motor torque temporary determination routine shown in FIG. That is, in SD41 of FIG. 21, the upper limit value TMGmax of the output torque of the MG 16 is calculated based on the take-out limit value WOUT. That is, the output PRMG of the RMG 70 is calculated from the equation 11 based on the output torque temporary determination value TRMGtmp of the RMG 70, and the maximum output PMG (= WOUT−PRMG) of the MG 16 is calculated from the output PRMG of the RMG 70. The maximum output torque TMG of the MG 16 is obtained based on the maximum output PMG (= WOUT−PRMG) of the MG 16, and this is set as TMGmaxp. Further, the minimum output PMG (= WIN−PRMG) of the MG 16 is calculated from the output PRMG of the RMG 70, and the minimum output torque TMG of the MG 16 is obtained based on the minimum output PMG (= WIN−PRMG) of the MG 16 from the formula 12. This is TMGminp. In Equation 12, PMGloss (NMG, TMG) is the loss of MG16.
[0122]
(Formula 11)
PRMG = NRMG × TRMGtmp + PRMGloss (NRMG, TRMG)
(Formula 12)
NMG x TMG + PMGloss (NMG, TMG) = PMG
[0123]
Next, in SD42 corresponding to the first motor operation control means 330, the output torque basic value TMGbase of MG16 is changed from the equation 13 to the driver requested torque Tdrv, the output torque provisional determination value TRMGtmp of the RMG70, and the engine output torque basic value TEbase. The output torque basic value TMGbase is commanded to be output from the MG 16. In Equation 13, GRF is a reduction ratio of the main drive device (planetary gear device 18 and continuously variable transmission 20). In Formula 13, since the output torque basic value TMGbase of MG16 is calculated based on the value obtained by subtracting the reduction gear ratio GRR from the driver requested torque Tdrv to the output torque provisional determination value TRMGtmp of RMG70, for example, the output torque of RMG70 in SD34. Is limited, the output torque basic value TMGbase of the MG 16 is increased accordingly, and the total driving force or regenerative braking force of the vehicle is held constant. Therefore, in this embodiment, the SD 42 also corresponds to the first electric motor operation increasing means 338.
[0124]
(Formula 13)
TMGbase = (Tdrv−TRMGtmp × GRR) / GRF−TEbase
[0125]
Subsequently, in SD43 corresponding to the first motor operation restriction means 334, the TMGmaxp and the above-described TMGmaxp for performing the restriction derived from the power storage device 112 and the restriction derived from the temperature of MG16 with respect to the output torque basic value TMGbase. Upper and lower limit guard processing using TMGminp, TMGmax and TMGmin is executed according to Equations 14 and 15, and the value after the upper and lower limit guard processing is determined as the output torque provisional determination value TMGtmp of MG16.
[0126]
(Formula 14)
TMGminp ≦ TMGbase ≦ TMGmaxp
(Formula 15)
TMGmin ≦ TMGbase ≦ TMGmax
[0127]
Returning to FIG. 18, in SD5, the provisional torque Tftmp of the front wheels (axle) is calculated from Expression 16, and the provisional torque Trtmp of the rear wheels (axle) is calculated from Expression 17.
[0128]
(Formula 16)
Tftmp = (TMG + TEbase) x (NIN / NOUT) x EFCVT x GRF
(Formula 17)
Trtmp = TRMGtmp × GRR
[0129]
Next, in SD6, the rear wheel temporary torque | Trtmp | is not more than a value obtained by multiplying the total value | Tftmp + Trtmp | of the front wheel temporary torque Tftmp and the rear wheel temporary torque Trtmp by the rear wheel torque distribution ratio Ktr. Is determined, that is, whether the ratio of the rear wheel temporary torque | Trtmp | to the total value | Tftmp + Trtmp | (| Trtmp | / | Tftmp + Trtmp |) is less than or equal to the rear wheel torque distribution ratio Ktr. If the determination in SD6 is affirmative, in SD7, the rear wheel temporary torque TRMGtmp is determined as the output torque TRMG of the RMG 70.
[0130]
However, if the determination at SD6 is negative, SD7 is executed after the output torque of RMG 70 is recalculated at SD8. In SD8, for example, a rear motor output torque recalculation routine shown in FIG. 22 is executed. In SD81 of FIG. 22, the rear-wheel torque Trtmp is calculated based on the front-wheel temporary torque Tftmp, the front-wheel torque distribution ratio (1-Ktr), and the ratio [Ktr / (1-Ktr)] of the rear-wheel torque distribution ratio Ktr. In SD82, the provisional output torque value TRMGtmp of the RMG 70 is calculated based on the rear wheel torque Trtmp and the reduction gear ratio GRR of the auxiliary drive device 12 from Equation 19. Here, for example, because the output torque of the MG 16 is limited by the SD 43, the ratio of the rear wheel temporary torque | Trtmp | to the total value | Tftmp + Trtmp | of the front wheel temporary torque Tftmp and the rear wheel temporary torque Trtmp | When Trtmp | / | Tftmp + Trtmp |) exceeds the rear wheel torque distribution ratio Ktr, the distribution ratio (Trtmp / Tftmp) of the front wheel temporary torque Tftmp and the rear wheel temporary torque Trtmp is determined in advance by the above equation 18. The distribution ratio [Ktr / (1-Ktr)] of the front wheel torque distribution ratio (1-Ktr) and the rear wheel torque distribution ratio Ktr, which are target distribution ratios, that is, the actual driving force distribution ratio or regeneration of the front and rear wheels Since the rear wheel temporary torque Trtmp is reduced corresponding to the limit amount of the output torque of the MG 16 so that the braking force distribution ratio becomes the target distribution ratio [Ktr / (1-Ktr)], the SD8 is the second Electric motor Corresponds to the motion reduction means 340.
[0131]
(Formula 18)
Trtmp = Tftmp × [Ktr / (1-Ktr)]
(Formula 19)
TRMGtmp = Trtmp × GRR
[0132]
As described above, according to the present embodiment, the correlation between the thermal ratings of the MG 16 (first electric motor) and the RMG 70 (second electric motor) is set to a specific state. The driving stability can be maintained.
[0133]
Further, according to the present embodiment, the thermal rating of the MG 16 (first electric motor) is higher than the thermal rating of the RMG 70 (second electric motor), so the heat of the RMG 70 that drives the rear wheels 80 and 82 is increased. The rating is lower than the thermal rating of the MG 16 that drives the front wheels 66 and 68, and the output of the RMG 70 on the rear wheel side is limited first. However, since the rear wheels 80 and 82 are used, the vehicle stability is relatively maintained. There are advantages.
[0134]
Further, according to the present embodiment, when the RMG 70 is restricted by the second motor operation restricting means 336 (SD34) (when the drive action is restricted or when the regenerative action is restricted), the first motor action increasing means 338 (SD42) makes the MG16. Therefore, the entire driving force or regenerative braking force of the vehicle is ensured while relatively maintaining the stability of the vehicle. For example, when the output of RMG 70 is limited, the output of MG 16 is increased so as not to change the total driving force of the vehicle corresponding to the driver request torque Tdrv, and when the regeneration of RMG 70 is limited, the total regenerative braking torque of the vehicle is changed. By increasing the regeneration of the MG 16 so that it does not occur, the total driving force or regenerative braking force of the vehicle is ensured while maintaining the stability of the vehicle.
[0135]
Further, according to the present embodiment, when the operation of the MG 16 is restricted by the first motor operation restriction means 334 (SD43), the second motor output reduction means 340 (SD8) sets the front / rear wheel distribution ratio as the target distribution ratio. That is, since the operation of the RMG 70 is reduced in order to set the torque distribution ratio of the rear wheels 80 and 82 to Ktr, the stability of the vehicle is ensured. For example, when the output of the MG 16 is limited, the output of the RMG 70 is reduced so that the torque sharing ratio of the front and rear wheels, that is, the rear wheel torque sharing ratio Ktr is maintained, or the front wheel drive (FF) is more than that. Similarly, when the regeneration of the MG 16 is restricted, the regeneration of the RMG 70 is reduced, so that the total driving force or regenerative braking force of the vehicle is ensured while maintaining the stability of the vehicle.
[0136]
FIG. 23 is a flowchart for explaining another control operation of FIG. This flowchart is different from FIG. 9 in that SA1 is executed when SA1 is deleted and the determination of SA2 is affirmed, and the others are the same. Portions common to those in FIG. 9 are denoted by the same reference numerals and description thereof is omitted.
[0137]
In SA30, it is determined whether or not the outside air temperature is a low temperature state that is equal to or lower than a predetermined temperature that may cause a change in the road surface friction coefficient, and whether the road surface gradient is traveling uphill with a predetermined angle or more. This uphill traveling is determined based on, for example, signals from front and rear G sensors (not shown). Alternatively, using the fact that the acceleration difference between the longitudinal acceleration and the acceleration just before starting stored when the vehicle is stopped or when the accelerator pedal 122 is not operated is coasting, the acceleration difference exceeds a predetermined value. In this case, it may be determined whether the vehicle is traveling uphill. In this case, there is an advantage that it is not erroneously determined as climbing even in high acceleration start on a flat road.
[0138]
If the determination at SA30 is affirmative, a first output torque region capable of obtaining a relatively large driving force is selected by executing SA16 and subsequent steps, and the RMG 70 is driven according to the first output torque region. The As a result, four-wheel drive traveling that provides a large driving force is performed. However, if the determination at SA30 is negative, the second output torque region in which the maximum torque is set smaller than the first output torque region is selected by executing SA19 and subsequent steps. RMG 70 is driven according to the output torque region. Thereby, although it is sufficient on a flat road and a high μ road, four-wheel drive running with reduced power consumption is performed, and the driving load of the RMG 70 is reduced.
[0139]
In SA30, it is determined whether or not the outside air temperature is a low temperature state that is a predetermined temperature or less that can cause a change in the friction coefficient of the road surface, or whether or not the road surface gradient is traveling uphill by a predetermined angle or more. Also good. In this case, when the outside air temperature is a low temperature state that is lower than a predetermined temperature that can cause a change in the road surface friction coefficient, and when the road surface gradient is traveling uphill with a predetermined angle or more, SA16 or lower is executed. The first output torque region capable of obtaining a large driving force is selected, and the RMG 70 is driven in accordance with the first output torque region. However, when the outside air temperature is not in a low temperature state below a predetermined temperature at which the road surface friction coefficient can change, and when the road surface gradient is not climbing up a predetermined angle or more, SA19 or less is executed, whereby the first output torque Since the second output torque region in which the maximum torque is set smaller than the region is selected, the RMG 70 is driven in accordance with the second output torque region.
[0140]
FIG. 24 is a view for temporarily increasing the driving force of the vehicle when starting uphill of the vehicle according to the main part of another control function provided in the hybrid control device 104, that is, the driving force of the front wheels 66 and 68. FIG. 6 is a functional block diagram for explaining high μ road assist control in which the RMG 70 is operated according to a predetermined driving force distribution ratio and driving force is also generated from the rear wheels 80 and 82. In FIG. 24, the target output determining means 348 is, for example, the degree of operation of the output operation means by the actual driver, for example, the operation amount of the accelerator pedal 122 (accelerator opening) θ from the previously stored relationship shown in FIG._AAnd target vehicle driving force F based on vehicle speed V_T1To decide. The relationship shown in FIG. 25 is obtained experimentally in advance in order to realize the driver's required driving force or required acceleration force.
[0141]
The slope start assist control means 350 has a driving force of a magnitude corresponding to the road gradient until the vehicle reaches a predetermined speed by the operation of the accelerator pedal 122 prior to the start operation of the vehicle, A driving force having such a magnitude that the reverse speed, that is, the slipping speed is a predetermined vehicle speed greater than zero or less, for example, a fine speed of about 1 to 3 km / h is applied to the vehicle. That is, the slope start assist control means 350 detects, for example, a stoppage longitudinal acceleration G corresponding to the slope in order to detect the slope (angle) of the road surface on which the vehicle is about to start._xstpIs stored based on an output signal of a longitudinal acceleration sensor (not shown) when the vehicle is stopped and the brake is operated, and a stationary longitudinal acceleration G corresponding to an actual gradient from a prestored relationship shown in FIG. 26, for example._xstpTentative correction driving force dF to be added to suppress reverse movement when starting uphill_KTentative correction driving force determining means 354 and provisional correction driving force dF determined by the temporary correction driving force determining means 354_KFor example, as shown in FIG. 27, the rising period (t₀~ T₁) To increase relatively quickly and temporarily correct driving force dF_KHowever, at the end of output, for example, a falling period of about 1 to 2 seconds (t₂~ T_Three) For the temporarily corrected driving force dF_KCorrection driving force generation means 355 for generating a correction driving force dF that decreases relatively gradually from the above, and the target driving force F for applying the correction driving force dF to the driving force of the vehicle_T1And a correction driving force applying means 356 for adding to. The relationship shown in FIG. 26 is experimentally obtained in advance so that the reverse speed of the vehicle at the time of starting uphill, that is, the slipping speed, becomes a very low speed below a predetermined vehicle speed greater than zero, for example, about 1 to 3 km / h. , Within a predetermined gradient range, that is, longitudinal acceleration G when the vehicle is stopped_xstpIs G₁Thru G₂Within the range of_xstpThe temporary correction driving force dF is proportionally increased_KHas been determined to increase. Longitudinal acceleration G when stopped_xstpIs G₁Is smaller than the reverse driving speed without applying the correction driving force dF, and the longitudinal acceleration G when the vehicle is stopped._xstpIs G₂Is larger than the provisional correction driving force dF in order to increase the subsequent reverse speed with the road inclination._KThe increase in is saturated.
[0142]
The accelerator opening θ_AFor example, a preset relationship θ as shown in FIG._A1= F (G_xstp, W) to actual road gradient G_xstpAnd the criterion value θ determined based on the vehicle weight W_A1Correction start impossibility determining means 358 for determining whether or not the driving force slope start assist correction is not necessary based on whether or not the vehicle has exceeded the threshold, and the accelerator opening θ_AIs a preset criterion value θ_A2And a correction stop determination means 360 for determining whether or not to stop the uphill start assist control for applying the correction drive force dF based on whether or not the upper limit is exceeded. The slope start assist control means 350, that is, the correction drive, is provided. The force applying unit 356 does not perform the climbing start assist control when the correction start impossibility determining unit 358 determines that the correction of the driving force is unnecessary, but the accelerator opening θ_AIs, for example, a criterion value θ of about 20% corresponding to a gradient of about 10 °._A1If it is determined that the vehicle has exceeded, the climbing start assist control is started. Further, the slope start assist control means 350, that is, the correction driving force applying means 356, is controlled by the correction stop determination means 360 during the uphill start assist control._AIs a preset criterion value θ_A2When it is determined that the engine speed exceeds the driving force, the driving force based on the acceleration operation of the accelerator pedal 122 is increased, so that the start assist control is stopped or terminated.
[0143]
Judgment reference vehicle speed V in which the vehicle speed V is preset to about 1 to 3 km / h₁The vehicle speed determination means 362 for determining whether or not the above and the brake pedal 124 are not operated for a predetermined time T₁Brake non-operation continuation determining means 364 is provided for determining whether or not the operation is continued. The slope start assist control means 350, that is, the correction driving force application means 356, is a judgment reference vehicle speed V in which the vehicle speed V is preset by the vehicle speed determination means 362.₁Not above (judgment standard vehicle speed V₁Or the brake non-operation continuation determining means 364 causes the brake pedal 124 to move for a predetermined time T.₁When it is determined that the vehicle has not been operated continuously, the corrected driving force dF is applied to the driving force of the vehicle.₁It is determined that the time is over or the brake pedal 124 is not operated for a predetermined time T.₁In the case where the above is continued, the uphill start assist control for applying the corrected driving force dF to the driving force of the vehicle is not performed. That is, the uphill start assist control by the slope start assist control means 350, that is, the correction driving force applying means 356, is performed when the vehicle is stopped or the determination reference vehicle speed V is very low.₁Lower than the predetermined time T even if the brake-on operation is performed or the off-operation is performed.₁This is performed when not continuous.
[0144]
The prime mover drive control means 366 has a target drive force F obtained by adding the corrected drive force dF by the corrected drive force applying means 356._T2(= F_T1+ DF) to control the output of the motor of the vehicle. For example, the target driving force F from the engine 14 and / or MG 16 that is the prime mover of the front wheel system._T1Is output, and the driving force dF for starting uphill is output from the RMG 70 which is the motor for the rear wheel system, so that before the accelerator pedal 122 is operated, the vehicle is moved backward by 1 to 3 km / h exclusively by the correcting driving force dF. When the start of the uphill is started by operating the accelerator pedal 122, the vehicle's total driving force is set to the target driving force F._T2And
[0145]
FIGS. 29 and 30 are flowcharts for explaining a main part of the control operation of the hybrid control device 104 of the present embodiment. FIG. 29 shows a driving force control routine, and FIG. 30 shows an uphill start correction driving force calculation routine. Show.
[0146]
In FIG. 29, in SE1, the accelerator opening θ, which is the vehicle speed V, the amount of operation of the accelerator pedal 122, from the output signal of a sensor (not shown)._A, Longitudinal acceleration G_xEtc. are read. Next, in SE2 corresponding to the target output determining means 348, the actual operation amount (accelerator opening) θ of the accelerator pedal 122 is obtained from the relationship stored in advance as shown in FIG._AAnd the vehicle speed V, the target driving force F that is the driver's required driving force_T1Is determined. Subsequently, in SE3 and SE4 corresponding to the slope start assist control means 350, the driving force having a magnitude corresponding to the road gradient until the vehicle reaches a predetermined speed by the operation of the accelerator pedal 122 prior to the start operation of the vehicle. In this case, the vehicle is provided with a driving force having a magnitude such that the reverse speed of the vehicle at the time of starting uphill, that is, the sliding speed, is a predetermined vehicle speed that is greater than zero or less, for example, a fine speed of about 1 to 3 km / h.
[0147]
FIG. 30 shows a routine for calculating the uphill start correction driving force for explaining the operation of SE3 in detail. In FIG. 30, in SE31 corresponding to the correction start impossibility determination means 358, the accelerator opening θ_AFor example, a preset relationship θ as shown in FIG._A1= F (G_xstp, W) to actual road gradient G_xstpAnd the criterion value θ determined based on the vehicle weight W_A1It is determined whether or not the driving force slope start assist correction is unnecessary based on whether or not the vehicle has exceeded the threshold. If the determination in SE31 is affirmative, the accelerator pedal 122 is in a state of being operated relatively large so as to be, for example, 20% or more for starting, so that the calculated corrected driving force dF is set to zero in SE32. Before and after the stop corresponding to the road gradient G sensor value G_xstpIs forcibly set to “0”, so that the calculation of the correction driving force is not substantially started.
[0148]
However, if the determination of SE31 is negative, the accelerator pedal 122 has not yet been started, and therefore SE33, SE34, and SE35 corresponding to the road surface gradient detecting means 352 are executed. In SE33, whether or not the vehicle is stopped is determined based on, for example, the vehicle speed V. In SE34, whether or not the brake pedal 124 is being operated is determined based on, for example, an output signal from a brake switch (not shown). If both the determinations of SE33 and SE34 are affirmed, in SE35, the output value of the front-rear G sensor at that time indicates the gravity value G representing the road surface gradient._xstpIs remembered as
[0149]
Next, in SE36 corresponding to the correction stop determination means 360, in order to determine whether or not the correction for starting uphill is unnecessary due to the increase of the driving force at the start by the operation of the accelerator pedal 122, the accelerator opening θ_AIs a preset criterion value θ_A2It is determined whether or not the value has been exceeded. When the determination in SE36 is affirmative, the front and rear G sensor value G corresponding to the road surface gradient is set so that the corrected driving force dF calculated in SE37 is zero._xstpIs preferentially set to “0”, so that the calculation of the correction driving force is not substantially started.
[0150]
However, if the determination in SE36 is negative, in the SE38 corresponding to the temporary correction driving force determining means 354, for example, the stoppage longitudinal acceleration G corresponding to the actual gradient from the previously stored relationship shown in FIG._xstpTentative correction driving force dF to be added to suppress reverse movement when starting uphill_KIs determined. Next, in SE39 corresponding to the corrected driving force generation means 355, the temporary corrected driving force dF_KFor example, as shown in FIG. 27, for example, immediately after the start of applying the correction driving force, the rising period (t₀~ T₁) To increase relatively quickly and temporarily correct driving force dF_KHowever, at the end of applying the correction driving force, for example, a falling period of about 1 to 2 seconds (t₂~ T_Three) For the temporarily corrected driving force dF_KA correction driving force dF that decreases relatively gradually is generated.
[0151]
If the determination in SE33 is negative, in SE40 corresponding to the vehicle speed determination means 362, a determination reference vehicle speed V in which the actual vehicle speed V is preset to about 1 to 3 km / h.₁It is determined whether or not the above has been reached. If the determination of SE40 is negative, the vehicle is still in a state where the vehicle speed is not generated due to starting uphill, and therefore SE36 and subsequent steps are executed in order to continue the control for applying the correction driving force for starting uphill. However, if the determination of SE40 is affirmative, the vehicle has already started moving forward when starting uphill, and it is no longer necessary to apply the correction driving force for starting uphill. The SE32 and the subsequent steps are executed in order to substantially end the control for applying the correction driving force.
[0152]
If the determination in SE34 is negative, in SE41 corresponding to the brake non-operation continuation determining means 364, the brake pedal 124 is set to a predetermined time T set to about 1 second, for example.₁It is determined whether or not continuous operation has been performed. If the determination at SE41 is negative, there is a possibility that the driver's intention to move forward exists, so that SE36 and below are required to continue the control for applying the correction driving force for starting uphill. If the determination of SE41 is affirmed, it is considered that there is no intention of the driver to move forward, and it is better to make the vehicle descend on the uphill road as usual. The SE32 and the subsequent steps are executed in order to substantially end the control for applying the driving force.
[0153]
Next, returning to FIG. 29, in SE4 corresponding to the corrected drive force applying means 356, the target drive obtained in SE2 is applied to apply the corrected drive force dF calculated in SE39 to the drive force of the vehicle. Force F_T1Is added to the final target driving force F after correction._T2Is calculated. Then, in SE5 corresponding to the prime mover drive control means 366, the target drive force F to which the corrected drive force dF calculated in SE39 is added._T2(= F_T1The output of the motor of the vehicle is controlled so that + dF) is obtained. For example, the target driving force F from the engine 14 and / or MG 16 that is the prime mover of the front wheel system._T1And the corrected driving force dF for starting uphill is output from the RMG 70, which is the motor for the rear wheel system, so that the total driving force of the vehicle becomes the target driving force F._T2It is said.
[0154]
In SE4, when SE31 (correction start impossibility determining means 358) determines that the correction of the driving force is not required, the accelerator opening θ is controlled by SE36 (correction stop determining means 360) during uphill starting assist control._AIs a preset criterion value θ_A2If the vehicle speed V is determined to exceed the vehicle speed V, the vehicle speed V is set in advance by the SE 40 (vehicle speed determination means 362).₁Not above (judgment standard vehicle speed V₁Or the brake pedal 124 is set to the predetermined time T by SE41 (brake non-operation continuation determining means 364).₁When it is determined that the vehicle has not been operated continuously, the longitudinal acceleration G when the vehicle is stopped_xstpIs set to zero and the corrected driving force dF obtained therefrom is also set to zero, so that the uphill start assist control for substantially applying the corrected driving force dF to the driving force of the vehicle is not performed.
[0155]
As described above, in the driving force control of the vehicle of this embodiment, according to the slope start assist control means 350, the stoppage longitudinal acceleration G representing the road gradient is shown._xstpWhen the vehicle driving control is performed to apply driving force to the driving wheels of the vehicle in response to the vehicle driving force F, the vehicle driving force F is set so that the reverse vehicle speed is less than a predetermined vehicle speed greater than zero when the vehicle starts to climb uphill._T2(= F_T1Since + dF) is set, when the vehicle starts on a hill, the vehicle is slightly retracted at a predetermined vehicle speed or less before the accelerator pedal 122 is depressed. I can know. Therefore, the driver can step on the vehicle according to the slope of the slope when starting the vehicle. That is, the conventional vehicle reverse force F, which is the difference between the urging force in the vehicle reverse direction based on gravity and the fixed creep force such as friction._RAs shown in FIG. 31, the road surface inclination angle, that is, the longitudinal acceleration G when the vehicle is stopped_xstpHowever, as described above, the provisional correction driving force dF is increased._KIs a longitudinal acceleration G when the vehicle is stopped from the relationship shown in FIG._xstpIs determined so as to increase as the value increases, and is applied to the vehicle driving force in the forward direction. Therefore, the urging force in the vehicle backward direction based on the gravity and the target driving force F are determined._T2(Temporarily corrected driving force dF when the vehicle is stopped_KThe actual reverse force F_R'Is the conventional vehicle reverse force F_RIt is made smaller and substantially constant. For example, the longitudinal acceleration G when stopped_xstpG gradually increases_a, G_b, G_cThe conventional retracting force is F_Ra, F_Rb, F_RcIn contrast, in this embodiment, the provisional correction driving force dF_KF that is small_Ra', F_Rb', F_Rc'And they are F_Ra', F_Rb', F_Rc'Is almost equivalent to each other.
[0156]
Further, according to the present embodiment, the stoppage longitudinal acceleration G representing the road gradient is shown._xstpWhen the vehicle driving control is performed to apply driving force to the driving wheels of the vehicle in response to the above, the brake non-operation continuation determining unit 364 determines that the non-operation continuation time of the brake pedal 124 is 1 when the vehicle is stopped. Predetermined T of about 2 seconds₁If it is determined that the time is longer than the time, the application of the driving force dF corresponding to the road gradient is stopped, so that the vehicle is allowed to slide down without the driver's intention to move forward. Can tell the degree of road gradient.
[0157]
Further, according to the corrected driving force applying means 356 of the present embodiment, the stoppage longitudinal acceleration G representing the road gradient when the vehicle starts to climb uphill._xstpIn the case of performing drive control of a vehicle that applies driving force to driving wheels in response to the driving force, when starting to apply the driving force dF corresponding to the road gradient, the driving force is quickly increased to drive corresponding to the road gradient. Since the driving force can be gradually reduced when the application of the force dF is stopped or ended, when the execution of the application of the driving force dF is started, the slippage at the start of the uphill road is quickly suppressed, and the driving force When the application of dF is stopped or ended, the application of driving force is stopped without a sense of incongruity.
[0158]
In addition, according to the present embodiment, one of the front wheels 66 and 68 and the rear wheels 80 and 82 can be driven by the first prime mover, for example, the engine 14 and the MG 16, and the other can be driven by the second prime mover, for example, the MG 70. In the vehicle, the control device for the four-wheel drive vehicle is configured so that the operation degree of the driver's output operation means, for example, the accelerator opening θ_AAnd target vehicle driving force F based on vehicle speed V_T1Is calculated (target output determining means 348), and the target driving force F_T1The driving force F to be output from the front wheel side and the rear wheel side based on_T2Is the stoppage longitudinal acceleration G representing the road gradient when the vehicle starts._xstpThe driving forces of the front wheels 66 and 68 and the rear wheels 80 and 82 are controlled so that the values are corrected based on the above (corrected driving force generating means 355, corrected driving force applying means 356). At the same time, the target driving force is achieved, and at the same time, when driving uphill, the driving force distribution of the front and rear wheels conforms to the gradient.
[0159]
Further, according to the present embodiment, the stoppage longitudinal acceleration G representing the road surface road gradient is shown._xstpIn the vehicle driving control for applying driving force to the driving wheels of the vehicle, that is, the climbing assist control, the temporary correction driving force determining means 354 causes the vehicle to fall within a predetermined road gradient range, that is, G₁Thru G₂Since the driving force of the vehicle is set corresponding to the road gradient so that the reverse vehicle speed is less than or equal to the predetermined vehicle speed within the range, the reverse vehicle speed is less than or equal to the predetermined vehicle speed when the road gradient exceeds the predetermined road gradient. Since the driving force of the vehicle set so as to be no longer increased, the driver can know the road gradient more accurately.
[0160]
Further, according to the present embodiment, the provisional corrected driving force determining means 354, the corrected driving force generating means 355, and the corrected driving force applying means 356 are used to determine the longitudinal acceleration G when the vehicle is stopped representing the road surface road gradient._xstpWhen the driving force is applied to the driving wheels of the vehicle in response to the above, the driving force F of the vehicle is set so that the reverse vehicle speed is less than a predetermined vehicle speed greater than zero when the vehicle starts to climb uphill._T2(= F_T1When + dF) is set, the predetermined vehicle speed is set to a vehicle speed of several kilometers, for example, 1 to 3 km / h, so that the downhill road is suppressed to a suitable value.
[0161]
Further, according to the present embodiment, the requested driving force F requested by the driver is corrected by the correction stop determination unit 360._T1That is, the required driving force F_T1Accelerator opening θ corresponding to_AIs a predetermined value θ that is not zero_A2When it is determined that the driving force dF has been exceeded, since the application of the driving force dF corresponding to the road gradient is stopped, the required driving force F_T1That is, the required driving force F_T1Accelerator opening θ corresponding to_AIs a predetermined value θ from zero_A2In the above range, a driving force that increases in response to an increase in road gradient is applied, and the vehicle is preferably prevented from retreating (sliding down).
[0162]
FIG. 32 is a functional block diagram for explaining a main part of another control function of vehicle driving force control by the hybrid control device 104. In FIG. 32, the target driving force calculation means 380 is based on, for example, the degree of operation of the output operation means by the actual driver, for example, the operation amount (accelerator opening) θ of the accelerator pedal 122 from the relationship stored in advance in FIG._AAnd the vehicle speed V, the target driving force, that is, the target driving torque T_TTo decide. The relationship shown in FIG. 33 is obtained experimentally in advance in order to realize the driver's required driving force or required acceleration force. The rear wheel distribution ratio reduction coefficient calculation means 382 is a target drive torque T obtained by the target drive force calculation means 380 from a previously stored relationship shown in FIG._TRear wheel distribution ratio reduction factor K based on_creepIs calculated. The relationship shown in FIG. 34 is experimentally obtained in advance in order to obtain the characteristics shown in FIG. 35 that reduce the operation of the RMG 70 as much as possible when the target driving force is small. The ideal rear wheel distribution ratio calculation means 384 is an ideal rear wheel distribution ratio K for realizing the ideal driving force distribution of the front and rear wheels based on the load distribution from the relational expression used in SC4 of FIG._troIs calculated. The vehicle start determination means 386 determines whether or not the vehicle is in a start state by determining whether the accelerator opening θ_AAnd determination based on the vehicle speed. When the vehicle start state is determined by the vehicle start determination unit 386, the rear wheel distribution ratio calculation unit 388 determines the rear wheel distribution ratio reduction coefficient K obtained by the rear wheel distribution ratio reduction coefficient calculation unit 382._creepAnd the ideal rear wheel distribution ratio K determined by the ideal rear wheel distribution ratio calculation means 384._troIs multiplied by the rear wheel distribution ratio K_trIs calculated. The front wheel driving force calculating means 390 is configured to output the target driving torque T_TAnd rear wheel distribution ratio K_trTo front wheel drive force (front wheel drive torque) T_F(= T_T× (1-K_tr)) And the rear wheel driving force calculating means 392 calculates the target driving torque T._TAnd rear wheel distribution ratio K_trTo rear wheel driving force (rear wheel driving torque) T_R(= T_T× K_tr) Is calculated. The prime mover drive control means 394 is a front wheel drive force (front wheel drive torque) T calculated by the front wheel drive force calculation means 390._FThe rear wheel driving force (rear wheel driving torque) T calculated by the rear wheel driving force calculating means 392 is controlled while controlling the engine 14 and the MG 16 that drive the front wheels 66 and 68._RThe RMG 70 that drives the rear wheels 80 and 82 is controlled so as to obtain four wheel drive driving.
[0163]
FIG. 35 shows the target (required) driving force T._T, Front wheel driving force T_F, Rear wheel driving force (rear wheel driving torque) T_RShows the relationship. Rear wheel distribution ratio reduction factor K_creepIn the relationship shown in FIG._TIs the predetermined value F₁Until the rear wheel distribution ratio reduction coefficient K_creepIs zero, the predetermined value F₁To a predetermined value F larger than that₂Until the target driving force T_TThe rear wheel distribution ratio reduction coefficient K_creepIncreases in proportion to the predetermined value F₂Exceeds the rear wheel distribution ratio reduction factor K_creepIs set to not saturate and increase. This predetermined value F₂Is determined based on the upper limit value (maximum value) of the driving force at which the front wheels 66 and 68 and the rear wheels 80 and 82 do not slip on low friction coefficient (μ) roads such as frozen roads and snowy roads. Yes. Therefore, the target driving force T_TIs the predetermined value F₂Exceeds the predetermined distribution ratio, the driving force is output from the front wheels 66, 68 and the rear wheels 80, 82 at an ideal distribution ratio.₂From the following to creep, the front-rear torque distribution ratio is increased on the front wheel side and decreased on the rear wheel side. FIG. 35 shows the ideal rear wheel distribution ratio K._troShows the characteristics when.
[0164]
FIG. 36 is a flowchart for explaining the driving force control operation of the hybrid control device 104 in the embodiment of FIG. In FIG. 36, in SF1, the accelerator opening θ_AAn input signal such as the vehicle speed V is read. Next, in SF2 corresponding to the target driving force calculation means 380, for example, the actual accelerator opening θ is obtained from the relationship stored in advance as shown in FIG._AAnd the vehicle speed V, the target driving force corresponding to the driver's required driving force, that is, the target driving torque T_TIs determined. Next, in SF3 corresponding to the ideal rear wheel distribution ratio calculating means 384, an ideal for realizing ideal driving force distribution of the front and rear wheels based on load distribution from the relational expression used in SC4 of FIG. 12, for example. Rear wheel distribution ratio K_troIs calculated. Then, in SF4 corresponding to the vehicle start determination means 386, it is determined whether or not the vehicle is in a start state. If the determination in SF4 is negative, the rear wheel distribution ratio reduction coefficient K is determined in SF5 in order to perform two-wheel drive by the front wheels 66 and 68._creepIs set to “0”.
[0165]
However, if the determination at SF4 is affirmative, in order to perform four-wheel drive by the front wheels 66 and 68 and the rear wheels 80 and 82, in SF6 corresponding to the rear wheel distribution ratio reduction coefficient calculation means 382, for example, FIG. The target driving torque T obtained by SF2 from the relationship stored in advance shown in FIG._TRear wheel distribution ratio reduction factor K based on_creepIs calculated. Subsequently, in SF7 corresponding to the rear wheel distribution ratio calculation means 388, the ideal rear wheel distribution ratio K_troRear wheel distribution ratio reduction factor K_creepRear wheel distribution ratio K by multiplying by_trIs calculated. Next, in SF8 corresponding to the rear wheel driving force calculation means 392, the target driving torque T_TAnd rear wheel distribution ratio K_trTo rear wheel driving force (rear wheel driving torque) T_R(= T_T× K_tr) Is calculated. Next, in SF9 corresponding to the front wheel driving force calculation means 390, the target driving torque T_TAnd rear wheel distribution ratio K_trTo front wheel drive force (front wheel drive torque) T_F(= T_T× (1-K_tr)) Is calculated. In the SF 10 corresponding to the prime mover drive control means 394, the front wheel driving force (front wheel driving torque) T calculated by the SF 9 is obtained._FThe engine 14 and the MG 16 that drive the front wheels 66 and 68 are controlled so that the rear wheel driving force (rear wheel driving torque) T calculated by the SF 8 is obtained._RThe RMG 70 that drives the rear wheels 80 and 82 is controlled so that the four-wheel drive traveling is performed. As a result, as shown in FIG.₂If it is smaller, the operation of the RMG 70 is reduced as much as possible, its power consumption and heat loss are reduced, and its use range is expanded.
[0166]
As described above, according to this embodiment, in the control device for a four-wheel drive vehicle, for example, the degree of operation of the output operation means by the actual driver from the pre-stored relationship shown in FIG. 13, FIG. 25, or FIG. That is, the accelerator opening θ_AAnd the target driving force F obtained based on the vehicle speed V_T(Target drive torque T_T) From the front wheel side and the rear wheel side, the vehicle state (the rear wheel load sharing ratio in FIG. 15 and paragraph 0107), the vehicle operating state (the difference between the front and rear wheel rotational speeds in FIG. 11 and paragraph 0093, FIG. The front wheel driving force and the rear wheel driving force are controlled on the basis of the front and rear G sensors in the paragraphs 0137 and 0138) or the road conditions (the road surface μ and the road gradient in FIG. 23 and the paragraphs 0138 and 0139). Target driving force F_TTherefore, four-wheel drive in which the vehicle state, the driving state of the vehicle, or the road state is appropriately reflected becomes possible.
[0167]
Further, according to the present embodiment, the first prime mover is a composite prime mover composed of a plurality of power sources, more specifically, a plurality of power sources having different types, that is, the engine 14 and the MG 16, so that the power source constituting the power source Since the engine 14 which is one of the above can be operated in a region where the efficiency thereof is high, fuel efficiency is improved.
[0168]
Further, according to the present embodiment, the second prime mover can be composed of one or two or more motors or a motor generator having a power generation function. In the present embodiment, the second prime mover is composed of one RMG 70, and 4 Since the rear wheels 80 and 82 of the wheel drive vehicle are driven, the vehicle is switched between the front wheel drive state and the four wheel drive state.
[0169]
Further, the control device for the four-wheel drive vehicle of the present embodiment provides an ideal rear wheel distribution ratio K corresponding to the driving force distribution between the front and rear wheels._troThe target driving force T_TIt changes based on. For example, the target driving force T_TIs the predetermined value F₂Target driving force T when falling below_TRear wheel distribution ratio reduction coefficient K determined based on_creepThe rear wheel distribution ratio K_troTherefore, when the driving force is small, the operation of the RMG 70 is suppressed as much as possible, and the temperature rise is avoided.
[0170]
In the present embodiment, when the vehicle is in a starting state, the driving force distribution between the front and rear wheels is the target driving force T._TTherefore, the distribution of the driving force between the front and rear wheels at the start of the four-wheel drive vehicle is determined by the target driving force T._TThere is an advantage that it is changed appropriately based on.
[0171]
In this embodiment, the ideal rear wheel distribution ratio K corresponding to the driving force distribution ratio of the front and rear wheels when the vehicle is in a starting state._troIs the target driving force T_TIs the predetermined value F₂The predetermined value F than when it is above₂If it is less, the distribution ratio of the wheels (the rear wheels 80 and 82 driven by the RMG 70 in this embodiment) driven by the thermally disadvantageous one of the first and second prime movers is made small. Therefore, the thermal load on the thermally disadvantageous one of the first prime mover and the second prime mover is reduced, so that the four-wheel drive can be further continued.
[0172]
Further, in this embodiment, when the vehicle is in a starting state, the driving force distribution ratio of the front and rear wheels is the target driving force T_TIs the predetermined value F₂The predetermined value F than when it is above₂If it is less than the rear wheel distribution ratio K which is the wheel side driven by the second prime mover_trSince the driving force output from the RMG 70 is reduced, the temperature rise of the RMG 70 is suppressed and the use range is expanded.
[0173]
In this embodiment, the target rear wheel distribution ratio K corresponding to the driving force distribution ratio_troValue F for changing₂Is determined from the maximum driving force at which the driving wheel does not slip on a predetermined low friction coefficient road surface, and therefore the predetermined value F at which the driving wheel does not slip.₂Target rear wheel distribution ratio K corresponding to driving force distribution ratio within the following target driving force range_troIs changed, the output of the RMG 70 corresponding to the second prime mover is reduced, and overheating is suitably prevented.
[0174]
Further, in the control device for the four-wheel drive vehicle of the present embodiment, the driving state of the vehicle is the start state (SA2 in FIG. 9), the acceleration state (SA6, SA7 in FIG. 9), and the low friction coefficient road surface traveling state (in FIG. 9). If the state is any one of SA1, SA3), it is a four-wheel drive that drives the front wheels and the rear wheels, and if it is neither, it is a two-wheel drive that drives one of the front wheels and the rear wheels. When the vehicle is in the starting state, the acceleration state, or the low friction coefficient road surface traveling state, the four-wheel drive automatically drives the front wheels and the rear wheels. Wheel drive is avoided, and overheating of the second prime mover that is operated to achieve four-wheel drive is suitably prevented.
[0175]
Further, the control device for a four-wheel drive vehicle according to the present embodiment performs four-wheel drive when the vehicle is traveling under a light load, that is, during deceleration traveling and during non-acceleration traveling without a brake operation (SA8 in FIG. 9). Therefore, it is automatically switched to four-wheel drive during light load traveling.
[0176]
In addition, the first prime mover and the second prime mover of the present embodiment include a power source that can be regeneratively controlled, that is, MG16 and RMG70, and the first prime mover includes the engine 14, so the engine 14 is in an efficient region. A driving force can be generated from the MG 16 or RMG 70 functioning as an electric motor so as to be operated.
[0177]
Further, in this embodiment, when the vehicle starts, the wheels may be driven only by the MG 16 or RMG 70 functioning as only the electric motor included in the first prime mover or the second prime mover or the electric motor capable of regenerating energy. (SA2 in FIGS. 5 and 9) Therefore, since the engine 14 is started in the non-operating state, the fuel efficiency of the vehicle is improved.
[0178]
Further, in this embodiment, when the vehicle is braked or coasting, regeneration control is performed using the MG 16 or RMG 70 functioning as an electric motor and a generator, so that the energy regeneration rate is improved and the fuel consumption of the vehicle is improved. Improved.
[0179]
Further, in the present embodiment, the first prime mover drives the wheel only by the engine 14 when the load exceeds a predetermined value, or drives the wheel by the engine 14 and the MG 16 functioning as a power source or an electric motor capable of regenerating energy. Sufficient driving force is ensured in a four-wheel drive vehicle.
[0180]
As mentioned above, although the Example of this invention was described in detail based on drawing, this invention is applied also in another aspect.
[0181]
For example, in the vehicle of the above-described embodiment, the front wheels 66 and 68 are driven by the main drive device 10 including the engine 14 and the MG 16, and the rear wheels 80 and 82 are driven by the auxiliary drive device 12 including the RMG 70. Although the four-wheel drive type is used, the front wheels 66 and 68 are driven by the auxiliary drive device 12 having the RMG 70, and the rear wheels 80 and 82 are driven by the main drive device 10 having the engine 14 and the MG 16. May be. The prime mover may be composed of at least one of an engine, an electric motor, a hydraulic motor, and the like.
[0182]
In the above-described embodiments, a plurality of types of control examples have been described. However, these control examples can be implemented in appropriate combinations in a predetermined vehicle.
[0183]
In the above-described embodiment, the front wheels 66 and 68 and the rear wheels 80 and 82 are driven by different prime movers. However, a four-wheel drive vehicle driven by a common prime mover may be used. In this case, the front wheels and the rear wheels are operatively connected to a common prime mover, and the drive force distribution ratio of the drive force output from the prime mover to the front wheels and rear wheels is changed by the drive force distribution clutch. It is. In such a control device for a four-wheel drive vehicle as well, the degree of operation of the output operation means by the driver (accelerator opening θ_A) And vehicle speed V, the target driving force T_TAnd the target driving force T_TThe driving force to be output from the front wheel side and the rear wheel side can be controlled based on the vehicle state. Even in this case, in order to obtain the driving force requested by the driver, four-wheel drive in which the vehicle state is appropriately reflected is possible.
[0184]
In the above-described embodiment, the corrected driving force dF for starting uphill is obtained in advance by the corrected driving force generator 355, and the target driving force F_T1In order to apply the corrected driving force dF to the driving force of the vehicle corresponding to the correction driving force applying means 356, the corrected driving force dF is converted to the target driving force F by_T1The correction coefficient (greater than 1) for starting uphill is obtained in advance, and the target driving force F₁In order to give the correction coefficient to the driving force of the vehicle corresponding to the target driving force F₁May be multiplied.
[0185]
In the prime mover driving force control means 366 of the above-described embodiment, the corrected driving force dF is output from the rear wheels 80 and 82 driven by the RMG 70, but the front wheels 66 and 68 driven by the engine 14 or the MG 16 are used. Or in the four-wheel drive state, the rear wheels 80 and 82 driven by the RMG 70 and the front wheels 66 driven by the engine 14 or MG 16 so as not to change the driving force distribution ratio at that time, 68 may be output.
[0186]
Further, the vehicle of the above-described embodiment is provided with the continuously variable transmission 20 in its power transmission path, but it is provided with a planetary gear type or a constant meshing parallel two-axis stepped transmission. There may be.
[0187]
In the above-described embodiment, the vehicle driving force control shown in FIGS. 29 and 30 is performed by the hybrid control device 104, but may be executed by another control device.
[0188]
As mentioned above, although the Example of this invention was described in detail based on drawing, this is an embodiment to the last, and this invention implements in the aspect which added various change and improvement based on the knowledge of those skilled in the art. Can do.
[Brief description of the drawings]
FIG. 1 is a skeleton diagram illustrating a configuration of a power transmission device of a four-wheel drive vehicle including a control device according to an embodiment of the present invention.
FIG. 2 is a diagram for explaining a main part of a hydraulic control circuit that controls the planetary gear device of FIG. 1;
FIG. 3 is a diagram for explaining a control device provided in the four-wheel drive vehicle of FIG. 1;
4 is a graph showing a best fuel consumption rate curve that is a target of an engine operating point controlled by the engine control device of FIG. 3; FIG.
FIG. 5 is a chart showing control modes selected by the hybrid control device of FIG. 3;
6 is an alignment chart for explaining the operation of the planetary gear device in the ETC mode controlled by the hybrid control device of FIG. 3; FIG.
7 is a functional block diagram illustrating a main part of a control function of the hybrid control device of FIG.
8 is a diagram showing a plurality of types of output torque regions stored in the output torque region storage means of FIG. 7. FIG.
9 is a flowchart for explaining a main part of the control operation of the hybrid control device of FIG. 3 and the like, and showing an output torque region switching and rear wheel switching control routine.
FIG. 10 is a flowchart for explaining a main part of the control operation of the hybrid control device of FIG. 3, and is a diagram showing a four-wheel drive stop control routine.
11 is a functional block diagram illustrating a main part of a control function of the hybrid control device of FIG.
12 is a flowchart for explaining a main part of the control operation of the hybrid control device of FIG. 3 and the like, and showing an output torque region switching and rear wheel switching control routine.
13 is a diagram showing a pre-stored relationship for calculating driver demand torque in the second prime mover operation control means of FIG. 11. FIG.
14 is a time chart illustrating the control operation of FIG.
15 is a functional block diagram illustrating a main part of a control function of the hybrid control device of FIG.
16 is a diagram showing an output torque region in which the temperature of MG or RMG of FIG. 1 or FIG. 3 is used as a parameter.
FIG. 17 is a graph showing temperature characteristics of acceptance limit value WIN and take-out limit value WOUT in the power storage device of FIG. 3;
18 is a flowchart illustrating a main part of a control operation of the hybrid control device of FIG.
FIG. 19 is a diagram showing an engine command torque calculation routine of SD2 in FIG.
FIG. 20 is a diagram showing an RMG output torque provisional determination routine of SD3 in FIG. 18;
FIG. 21 is a diagram showing an MG output torque determination routine of SD4 in FIG.
FIG. 22 is a diagram showing an RMG output torque recalculation routine of SD8 in FIG. 18;
FIG. 23 is a diagram showing another example of the flowchart of FIG. 9;
24 is a functional block diagram illustrating another main part of the control function of the hybrid control device of FIG. 3. FIG.
25 is a diagram showing a relationship stored in advance used for determining a target driving force by the target output determining means of FIG. 24. FIG.
FIG. 26 is a diagram showing a pre-stored relationship used for determining the temporary correction driving force by the temporary correction driving force determination means in FIG.
27 is a diagram showing a relationship stored in advance used for generating a correction driving force by the correction driving force generation means of FIG. 24. FIG.
FIG. 28 is a diagram showing a pre-stored relationship used for determining a determination reference value for determining whether or not correction can be started in the correction start / impossibility determination unit of FIG. 24;
FIG. 29 is a flowchart for explaining a main part of the control operation of the hybrid control device of FIG. 24, and shows a driving force control routine.
FIG. 30 is a flowchart for explaining a main part of the control operation of the hybrid control device of FIG. 24, showing an uphill start correction driving force calculation routine.
31 is a road surface inclination angle (longitudinal acceleration G when stopped), which is a main part of the control operation of the hybrid control device of FIG._xstpIt is a figure explaining the change of retreat force with respect to the change of.
32 is a functional block diagram illustrating a main part of another drive control function by the hybrid control device of FIG. 3. FIG.
33 is a diagram showing a pre-stored relationship used for calculating the target driving force by the target driving force calculating means of FIG. 32. FIG.
34 is a diagram showing a pre-stored relationship used for calculating a rear wheel distribution ratio reduction coefficient from the rear wheel distribution ratio reduction coefficient calculation means of FIG. 32. FIG.
35 explains the relative relationship between the target driving force calculated by the target driving force calculating unit shown in FIG. 32, the front wheel driving force calculated by the front wheel driving force calculating unit, and the rear wheel driving force calculated by the rear wheel driving force calculating unit. FIG.
36 is a flowchart illustrating a driving force control operation by the hybrid control device of FIG. 32. FIG.
[Explanation of symbols]
14: Engine (first prime mover)
66, 68: Front wheel
70: Rear motor generator (second prime mover)
80, 82: Rear wheel
348: Target output determining means
350: Slope start assist control means
352: gradient detection means
354: Temporary correction driving force determining means
355: Correction driving force generation means
356: Correction driving force applying means

Claims (21)

In a control device for a four-wheel drive vehicle in which one of a front wheel and a rear wheel can be driven by a first prime mover and the other can be driven by a second prime mover,
A target driving force is obtained based on the degree of operation of the output operation means by the driver and the vehicle speed, and the front wheel driving force and the rear wheel driving force for outputting the target driving force from the front wheel side and the rear wheel side are determined in the vehicle state or A control device for a four-wheel drive vehicle , wherein the control is performed based on a driving state of the vehicle, and the driving force distribution between the front and rear wheels is changed based on the target driving force .   The control apparatus for a four-wheel drive vehicle according to claim 1, wherein the first prime mover is a composite prime mover including a plurality of power sources.   The control apparatus for a four-wheel drive vehicle according to claim 1, wherein the first prime mover is a composite prime mover composed of a plurality of power sources having different types.   The control device for a four-wheel drive vehicle according to any one of claims 1 to 3, wherein the second prime mover comprises at least one electric motor.   The control device for a four-wheel drive vehicle according to claim 4, wherein the second prime mover drives a rear wheel of the four-wheel drive vehicle. 2. The control apparatus for a four-wheel drive vehicle according to claim 1 , wherein the vehicle state is a start state of the vehicle, and the driving force distribution between the front and rear wheels is changed based on the target driving force when the vehicle starts. The vehicle state is a start state of the vehicle, and when the vehicle starts, the first motor and the front motor and the front wheel are distributed when the target drive force is less than a predetermined value when the target drive force is less than a predetermined value. The control device for a four-wheel drive vehicle according to any one of claims 1 to 6 , wherein a change is made so as to reduce a distribution ratio of wheels driven by a thermally disadvantageous prime mover of the second prime mover. The vehicle state is a starting state of the vehicle, and when the vehicle starts, the driving force distribution ratio of the front and rear wheels is driven by the second prime mover when the target driving force is less than a predetermined value, rather than when the target driving force is not less than the predetermined value. The control device for a four-wheel drive vehicle according to any one of claims 1 to 7, wherein the control device is changed so as to reduce a distribution ratio on a wheel side. Wherein the predetermined value is four-wheel drive vehicle control apparatus according to claim 7 or 8 which has been determined from the maximum driving force that does not lead to slip at a predetermined low friction coefficient road surface. The four-wheel drive vehicle of the control device,
When the driving state of the vehicle is one of a start state, an acceleration state, and a low friction coefficient road surface driving state, it is a four-wheel drive that drives the front wheels and the rear wheels. The control device for a four-wheel drive vehicle according to any one of claims 1 to 9, wherein two-wheel drive for driving one of them is used. 11. The control device for a four-wheel drive vehicle according to claim 10 , wherein when the vehicle is running at a light load, the vehicle is driven by four wheels. The control device for a four-wheel drive vehicle according to claim 10 or 11 , wherein the first prime mover and the second prime mover include an electric motor. The control apparatus for a four-wheel drive vehicle according to claim 12 , wherein the first prime mover includes an engine. 14. The control device for a four-wheel drive vehicle according to claim 12 or 13 , wherein when the vehicle starts, the wheels may be driven only by the electric motor included in the first prime mover or the second prime mover. The control device for a four-wheel drive vehicle according to any one of claims 12 to 14 , wherein regenerative control is performed using the electric motor as a generator during braking or coasting of the vehicle. The control device for a four-wheel drive vehicle according to claim 10 or 11 , wherein the first prime mover or the second prime mover includes a power source capable of regenerative control. The control apparatus for a four-wheel drive vehicle according to claim 16 , wherein the first prime mover includes an engine. The control device for a four-wheel drive vehicle according to claim 16 or 17 , wherein when the vehicle is started, the wheel may be driven only by an electric motor capable of regenerating energy included in the first prime mover or the second prime mover. The control device for a four-wheel drive vehicle according to any one of claims 16 to 18 , wherein regeneration control using the electric motor capable of energy regeneration is performed during braking or coasting of the vehicle. The control device for a four-wheel drive vehicle according to any one of claims 17 to 19 , wherein the first prime mover drives the wheel only by the engine or a wheel by a power source capable of regenerating energy when the load exceeds a predetermined value. . The control device for a four-wheel drive vehicle according to any one of claims 13 to 15 , wherein the first prime mover drives a wheel only by an engine or a wheel by an engine and an electric motor when the load exceeds a predetermined value.

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