JP3593838B2

JP3593838B2 - Vehicle driving force control device

Info

Publication number: JP3593838B2
Application number: JP06938197A
Authority: JP
Inventors: 秀策片倉; 英明渡辺; 克彦土屋
Original assignee: Nissan Motor Co Ltd
Current assignee: Nissan Motor Co Ltd
Priority date: 1997-03-24
Filing date: 1997-03-24
Publication date: 2004-11-24
Anticipated expiration: 2017-03-24
Also published as: JPH10266882A

Description

【０００１】
【発明の属する技術分野】
本発明は、車両の駆動力制御装置、特にアクセル開度および車速に応じて決定する目標駆動力を、スムーズな車両走行が補償される態様で決定し得るようにした車両の駆動力制御装置に関するものである。
【０００２】
【従来の技術】
車両の駆動力を制御するに際しては、例えば特開平７−１７２２１７号公報に記載されているように、搭載エンジンおよび自動変速機の双方を制御して車両の駆動力を設定値に持ち来たしたり、或いはエンジンおよび自動変速機をそれぞれを個々に制御して車両の駆動力を設定値に持ち来すが、
いずれにしても、車両の走行抵抗や路面勾配を考慮しない基本的な目標駆動力を演算するに際しては、図５に例示する線図に対応したマップをもとに、アクセルペダル踏み込み量（アクセル開度）ＡＰＳ、および車速ＶＳＰから目標駆動力Ｔを検索および線形補間により求める。
【０００３】
【発明が解決しようとする課題】
ところで上記の目標駆動力Ｔのマップは常識的には、図５に示すようにアクセル開度ＡＰＳの格子軸を例えば０／８開度〜８／８開度に８等分したＡＰＳ格子点ごとに、車速ＶＳＰに対する目標駆動力Ｔのマップとして予め定めておくのが一般的である。
【０００４】
しかしてこの場合、低アクセル開度域において相隣れるＡＰＳ格子点間での駆動力段差が大きくなり、この間を直線補間した時に、アクセル開度変化に対するエンジン出力トルクの変化がリニヤでないことから、正確な目標駆動力を求めることができず、駆動力制御が狙い通りのものでなくなったり、アクセル開度を変化させた時にエンジン出力トルクが急変して、低アクセル開度域で滑らかな駆動力制御を実現することができない、といったような問題の発生が懸念される。
【０００５】
請求項１に記載の発明は、低アクセル開度域においても相隣れるＡＰＳ格子点間での駆動力段差が大きくなることのないようなマップを用いることで上記の問題を解消することを目的とする。
【０００６】
請求項２に記載の発明は、低アクセル開度域においてはむしろ、相隣れるＡＰＳ格子点間での駆動力段差が小さくなるようなマップを用いることで、微妙なアクセル開度操作をする低アクセル開度域において、当該アクセル操作に見合った正確で滑らかな駆動力制御が可能になるようにすることを目的とする。
【０００７】
請求項３に記載の発明は、アクセル開度および車速に対応する目標駆動力の具体的な求め方を提案することを目的とする。
【０００８】
【課題を解決するための手段】
これらの目的のため、先ず請求項１に記載の発明は、
アクセル開度格子軸上における予定のアクセル開度格子点ごとに設定された、車速および目標駆動力の２次元座標上の目標駆動力曲線から、車速に対応する目標駆動力を求め、車両の駆動力をこの目標駆動力となるよう制御するようにした車両の駆動力制御装置において、
前記２次元座標上における前記予定のアクセル開度格子点ごとの目標駆動力曲線と、同じ２次元座標上に表記した車両の走行抵抗曲線との交点がそれぞれ、車速を目盛った車速軸方向に見てほぼ等間隔になるよう前記予定のアクセル開度格子点を定めたことを特徴とするものである。
【０００９】
また請求項２に記載の発明は、
アクセル開度格子軸上における予定のアクセル開度格子点ごとに設定された、車速および目標駆動力の２次元座標上の目標駆動力曲線から、車速に対応する目標駆動力を求め、車両の駆動力をこの目標駆動力となるよう制御するようにした車両の駆動力制御装置において、
前記２次元座標上における前記予定のアクセル開度格子点ごとの目標駆動力曲線と、同じ２次元座標上に表記した車両の走行抵抗曲線との交点がそれぞれ、車速を目盛った車速軸方向に見て、アクセル開度格子軸の低開度側ほど密に存在するよう前記予定のアクセル開度格子点を定めたことを特徴とするものである。
【００１０】
更に請求項３に記載の発明は、上記第１発明または第２発明において、
前記予定のアクセル開度格子点のうち、現在のアクセル開度に対応したアクセル開度格子点を挟むハイ側における予定のアクセル開度格子点およびロー側における予定のアクセル開度格子点に係わる目標駆動力曲線から、車速に対応するハイ側目標駆動力およびロー側目標駆動力をそれぞれ求め、これらハイ側目標駆動力およびロー側目標駆動力を線形補間して車速に対応する目標駆動力を求めるよう構成したことを特徴とするものである。
【００１１】
【発明の効果】
請求項１に記載の発明において駆動力制御装置は、アクセル開度格子軸上における予定のアクセル開度格子点ごとに設定された、車速および目標駆動力の２次元座標上の目標駆動力曲線から、車速に対応する目標駆動力を求め、車両の駆動力をこの目標駆動力となるよう制御する。
【００１２】
ところで上記２次元座標上における上記予定のアクセル開度格子点ごとの目標駆動力曲線と、同じ２次元座標上に表記した車両の走行抵抗曲線との交点がそれぞれ、車速を目盛った車速軸方向に見てほぼ等間隔になるよう前記予定のアクセル開度格子点を定めたことから、
低アクセル開度域においても相隣れるアクセル開度格子点間での駆動力段差が大きくなることがなく、この間を直線補間して求める目標駆動力が正確になり、駆動力制御を狙い通りに行い得ると共に、低アクセル開度域でもアクセル開度の変化に対しエンジン出力トルクが急変することがなく、低アクセル開度域での滑らかな駆動力制御を補償することができる。
【００１３】
請求項２に記載の発明において駆動力制御装置は、アクセル開度格子軸上における予定のアクセル開度格子点ごとに設定された、車速および目標駆動力の２次元座標上の目標駆動力曲線から、車速に対応する目標駆動力を求め、車両の駆動力をこの目標駆動力となるよう制御する。
【００１４】
ところで上記２次元座標上における上記予定のアクセル開度格子点ごとの目標駆動力曲線と、同じ２次元座標上に表記した車両の走行抵抗曲線との交点がそれぞれ、車速を目盛った車速軸方向に見て、アクセル開度格子軸の低開度側ほど密に存在するよう前記予定のアクセル開度格子点を定めたことから，
低アクセル開度域においてはむしろ、相隣れるアクセル開度格子点間での駆動力段差が小さくなり、微妙なアクセル開度操作をする当該低アクセル開度域において、当該アクセル操作に見合った正確で滑らかな駆動力制御が可能になる。
【００１５】
請求項３に記載の発明においては、目標駆動力を求めるに際し、
上記予定のアクセル開度格子点のうち、現在のアクセル開度に対応したアクセル開度格子点を挟むハイ側における予定のアクセル開度格子点およびロー側における予定のアクセル開度格子点に係わる目標駆動力曲線から、車速に対応するハイ側目標駆動力およびロー側目標駆動力をそれぞれ求め、
これらハイ側目標駆動力およびロー側目標駆動力を線形補間して車速に対応した目標駆動力を求めることから、
簡単な演算により車両の目標駆動力を求めることができる。
【００１６】
【発明の実施の形態】
以下、本発明の実施の形態を図面に基づき詳細に説明する。
図１は、本発明の一実施の形態になる駆動力制御装置を備えた車両のパワートレーン制御装置で、車両のパワートレーンはエンジン１および無段変速機２のトルクコンバータＴ／Ｃを介した相互タンデム結合により構成する。
【００１７】
エンジン１は、運転者が踏み込むアクセルペダル３にリンク結合されていない、所謂電子制御スロットルバルブ４の開度により出力を決定され、電子制御スロットルバルブ４の開度をスロットルアクチュエータ５により制御するものとする。
また自動変速機２は、コントロールバルブ６に内蔵したステップモータ７に応動する変速制御弁（図示せず）により変速比を決定され、この変速比でトルクコンバータＴ／Ｃからのエンジン回転を変速して車輪に出力するものとする。
【００１８】
スロットルアクチュエータ５を介したスロットルバルブ４の開度制御（エンジン出力制御）、およびステップモータ７を介した無段変速機２の変速制御は、共通なコントローラ８によりこれらを総合制御し、
コントローラ８には、アクセルペダル３の踏み込み量（アクセル開度）ＡＰＳを検出するアクセル開度センサ９からの信号、車速ＶＳＰを検出する車速センサ１０からの信号、および路面勾配θを検出する勾配センサ１１からの信号をそれぞれ入力する。
【００１９】
コントローラ８は、これら入力情報をもとに図２および図３に示す制御プログラムを実行してエンジン１および無段変速機２を総合制御するもので、図２はそのメインルーチン、図３は目標駆動力を演算するためのサブルーチンをそれぞれ示す。
図２のステップ２０〜２２においては、アクセル開度ＡＰＳ、車速ＶＳＰ、および路面勾配θを順次読み込み、次いでステップ２３において、走行抵抗および路面勾配を考慮しない純粋な車両の目標駆動力を算出する。
【００２０】
当該目標駆動力の算出は、図４に示すような目標駆動力線図に対応したマップに基づき図３のサブルーチンを実行して行うものとする。
ここで図４の目標駆動力線図を説明するに、この線図は、図５と同じ目標駆動力曲線を実線で示し、これに、１点鎖線で示す走行抵抗曲線（ロードロード線）Ｒ／Ｌをも併記したものである。
なお走行抵抗曲線（ロードロード線）Ｒ／Ｌは周知の通り、車両の走行抵抗と駆動力とが釣り合って、対応する車速を維持するのに丁度必要な駆動力を結んだ曲線である。
【００２１】
そして本実施の形態においては、目標駆動力線図を特に図４に示すように、アクセル開度（ＡＰＳ）格子軸を等分したＡＰＳ格子点ごとの、実線で示す目標駆動力曲線（図５におけると同じ曲線）に付加して、２点鎖線で示すような別のＡＰＳ格子点に対応した目標駆動力曲線を設定する。
かかる目標駆動力曲線の追加、つまり上記別のＡＰＳ格子点の設定に際しては、目標駆動力曲線を表記した車速および目標駆動力の２次元座標上におけるＡＰＳ格子点ごとの目標駆動力曲線と、同じ２次元座標上に表記した車両の走行抵抗曲線Ｒ／Ｌとの交点がそれぞれ、図４に示すように、車速を目盛った横軸（車速軸）方向に見てほぼ等間隔になるよう、当該ＡＰＳ格子点の設定および目標駆動力曲線の追加を行う。
【００２２】
コントローラ８が実行する図３の目標駆動力算出ルーチンを説明するに、先ずステップ３０において、ＡＰＳ格子軸上における予定のＡＰＳ格子点のうち、現在のアクセル開度ＡＰＳの直上におけるハイ側ＡＰＳ格子点および直下におけるロー側ＡＰＳ格子点を記憶する。
次いでステップ３１において、ハイ側ＡＰＳ格子点に対応した目標駆動力マップから、車速ＶＳＰに対応したハイ側目標駆動力を検索し、
更にステップ３２において、ロー側ＡＰＳ格子点に対応した目標駆動力マップから、車速ＶＳＰに対応したロー側目標駆動力を検索する。
【００２３】
そしてステップ３３において、上記のハイ側目標駆動力およびロー側目標駆動力間を線形補間し、これにより、現在のアクセル開度ＡＰＳに対応した目標駆動力を算出する。
【００２４】
かように現在のアクセル開度ＡＰＳに対応した目標駆動力を算出した後は、制御を図２のステップ２４に戻し、ここで車両の走行抵抗分を算出し、
次いでステップ２５において、路面勾配θに応じた車両駆動力増減分（登坂路で増分となり、降坂路では減分となる）を算出する。
さらにステップ２６において、前記の目標駆動力と、走行抵抗分と、路面勾配に応じた車両駆動力増減分とを合計して車両駆動力の設定値を求め、
その後ステップ２７において、車両駆動力がこの設定値になるよう、例えば特開平７−１７２２１７号公報に記載されているごとき考え方に基づき、エンジン１および無段変速機２を総合制御する。
【００２５】
ここでエンジン１の制御は、スロットルアクチュエータ５を介したスロットルバルブ４の開度制御とし、無段変速機２の制御は、ステップモータ６を介した変速制御であること勿論である。
【００２６】
かかる駆動力制御によれば、図４に示すようにＡＰＳ格子点ごとの目標駆動力曲線と、車両の走行抵抗曲線との交点がそれぞれ、車速軸方向に見てほぼ等間隔になるようＡＰＳ格子点を定めたことから、
低アクセル開度域においても相隣れるアクセル開度格子点間での駆動力段差が大きくなることがなく、この間を直線補間して求める目標駆動力が正確になり、駆動力制御を狙い通りに行い得ると共に、低アクセル開度域でもアクセル開度の変化に対しエンジン出力トルクが急変することがなく、低アクセル開度域での滑らかな駆動力制御を補償することができる。
【００２７】
なお上記のごとく、ＡＰＳ格子点ごとの目標駆動力曲線と、車両の走行抵抗曲線との交点がそれぞれ、車速軸方向に見てほぼ等間隔になるようＡＰＳ格子点を定める代わりに、
上記の交点が車速軸方向に見て、ＡＰＳ格子軸の低開度側ほど密に存在するようＡＰＳ格子点を定めるのが一層好適である。
この場合、低アクセル開度域においては相隣れるアクセル開度格子点間での駆動力段差が一層小さくなり、微妙なアクセル開度操作をする当該低アクセル開度域において、当該アクセル操作に見合った正確で滑らかな駆動力制御が可能になる。
【００２８】
更に、現在のアクセル開度ＡＰＳに対応した目標駆動力を求めるに際し前述の通り、現在のアクセル開度ＡＰＳの直上および直下におけるハイ側のＡＰＳ格子点およびロー側におけるＡＰＳ格子点に係わる目標駆動力曲線から、車速に対応するハイ側目標駆動力およびロー側目標駆動力をそれぞれ求め、
これらハイ側目標駆動力およびロー側目標駆動力を線形補間して目標駆動力を求めることから、簡単な演算により車両の目標駆動力を求めることができる。
【００２９】
なお上述の実施形態においては、図４に示すようにアクセル開度（ＡＰＳ）をパラメータとし、車速ＶＳＰに関する線図として目標駆動力Ｔを表した目標駆動力線図を基に目標駆動力Ｔを求める場合について説明したが、この代わりに、
車速ＶＳＰをパラメータとし、アクセル開度（ＡＰＳ）に関する線図として目標駆動力Ｔを表した目標駆動力線図を基に目標駆動力Ｔを求める場合についても、同様の考え方により同様の作用効果を達成することができる。
この場合、車速（ＶＳＰ）格子軸を等分した車速格子点ごとの目標駆動力曲線に、前記と同じ考え方に基づく別の車速格子点に対応した目標駆動力曲線を設定し、
車速（ＶＳＰ）格子軸上におけるこれら予定の車速格子点ごとに設定された、アクセル開度（ＡＰＳ）および目標駆動力Ｔの２次元座標上の目標駆動力曲線から目標駆動力Ｔを求める。
【図面の簡単な説明】
【図１】本発明の一実施の形態になる駆動力制御装置を備えた車両用パワートレーンの総合制御システム図である。
【図２】同実施の形態になるコントローラが実行する駆動力制御プログラムのメインルーチを示すフローチャートである。
【図３】同駆動力制御プログラム中の目標駆動力算出処理に関するサブルーチンを示すフローチャートである。
【図４】同実施の形態で用いる目標駆動力マップを線図で表した目標駆動力特性線図である。
【図５】従来の駆動力制御装置で用いられる一般的な目標駆動力マップを線図で表した目標駆動力特性線図である。
【符号の説明】
１エンジン
２無段変速機
３アクセルペダル
４電子制御スロットルバルブ
５スロットルアクチュエータ
６コントロールバルブ
７ステップモータ
８コントローラ
９アクセル開度センサ
１０車速センサ
１１路面勾配センサ[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a driving force control device for a vehicle, and more particularly, to a driving force control device for a vehicle capable of determining a target driving force determined according to an accelerator opening and a vehicle speed in a manner that smooth vehicle running is compensated. Things.
[0002]
[Prior art]
When controlling the driving force of the vehicle, for example, as described in JP-A-7-172217, the vehicle driving force is brought to a set value by controlling both the mounted engine and the automatic transmission, Alternatively, the engine and the automatic transmission are individually controlled to bring the driving force of the vehicle to the set value,
In any case, when calculating the basic target driving force without considering the running resistance of the vehicle and the road surface gradient, the accelerator pedal depression amount (accelerator opening) is determined based on a map corresponding to the diagram illustrated in FIG. Degree) The target driving force T is obtained from the APS and the vehicle speed VSP by retrieval and linear interpolation.
[0003]
[Problems to be solved by the invention]
By the way, the above-mentioned map of the target driving force T is a common sense, as shown in FIG. 5, for each APS grid point obtained by equally dividing the grid axis of the accelerator opening APS into, for example, 0/8 to 8/8. Generally, a map of the target driving force T with respect to the vehicle speed VSP is generally determined in advance.
[0004]
In this case, however, the driving force step between adjacent APS lattice points in the low accelerator opening range becomes large, and when linear interpolation is performed between these points, the change in the engine output torque with respect to the change in the accelerator opening is not linear. Accurate target driving force cannot be obtained, driving force control is not as intended, or engine output torque changes suddenly when the accelerator opening is changed, resulting in smooth driving force in the low accelerator opening range It is feared that such a problem that control cannot be realized may occur.
[0005]
An object of the present invention is to solve the above problem by using a map in which a driving force step between adjacent APS lattice points does not increase even in a low accelerator opening range. And
[0006]
According to the second aspect of the present invention, in a low accelerator opening range, a map in which a driving force step between adjacent APS lattice points is reduced is used to perform a delicate accelerator opening operation. It is an object of the present invention to enable accurate and smooth driving force control appropriate for the accelerator operation in an accelerator opening range.
[0007]
It is an object of the present invention to propose a specific method of obtaining a target driving force corresponding to an accelerator opening and a vehicle speed.
[0008]
[Means for Solving the Problems]
For these purposes, first, the invention described in claim 1 is:
The target driving force corresponding to the vehicle speed is obtained from the target driving force curve on the two-dimensional coordinates of the vehicle speed and the target driving force set for each of the predetermined accelerator opening lattice points on the accelerator opening lattice axis, and the vehicle is driven. In a vehicle driving force control device that controls the force to be the target driving force,
The intersections of the target driving force curve for each of the planned accelerator opening grid points on the two-dimensional coordinates and the running resistance curve of the vehicle written on the same two-dimensional coordinates are respectively set in the vehicle speed axis direction indicating the vehicle speed. It is characterized in that the predetermined accelerator opening degree grid points are determined so as to be substantially equally spaced when viewed.
[0009]
The invention according to claim 2 is
The target driving force corresponding to the vehicle speed is obtained from the target driving force curve on the two-dimensional coordinates of the vehicle speed and the target driving force set for each of the predetermined accelerator opening lattice points on the accelerator opening lattice axis, and the vehicle is driven. In a vehicle driving force control device that controls the force to be the target driving force,
The intersections of the target driving force curve for each of the planned accelerator opening grid points on the two-dimensional coordinates and the running resistance curve of the vehicle written on the same two-dimensional coordinates are respectively set in the vehicle speed axis direction indicating the vehicle speed. In this case, the predetermined accelerator opening lattice point is determined so that the lower the opening degree of the accelerator opening lattice axis, the closer the opening.
[0010]
The invention according to claim 3 is the first invention or the second invention, wherein
Of the planned accelerator opening grid points, a target related to a planned accelerator opening grid point on the high side and a planned accelerator opening grid point on the low side sandwiching the accelerator opening grid point corresponding to the current accelerator opening. From the driving force curve, a high-side target driving force and a low-side target driving force corresponding to the vehicle speed are respectively obtained, and the high-side target driving force and the low-side target driving force are linearly interpolated to obtain a target driving force corresponding to the vehicle speed. It is characterized by having such a configuration.
[0011]
【The invention's effect】
According to the first aspect of the present invention, the driving force control device calculates a target driving force curve on a two-dimensional coordinate of the vehicle speed and the target driving force set for each predetermined accelerator opening lattice point on the accelerator opening lattice axis. , A target driving force corresponding to the vehicle speed is obtained, and the driving force of the vehicle is controlled to be the target driving force.
[0012]
By the way, the intersections of the target driving force curve for each of the planned accelerator opening lattice points on the two-dimensional coordinates and the running resistance curve of the vehicle described on the same two-dimensional coordinates are respectively in the vehicle speed axis direction indicating the vehicle speed. Since the planned accelerator opening degree grid points were determined so that they would be approximately equally spaced,
Even in the low accelerator opening range, the driving force step between adjacent accelerator opening lattice points does not increase, the target driving force obtained by linear interpolation between them becomes accurate, and the driving force control is aimed at In addition, the engine output torque does not suddenly change in response to a change in the accelerator opening even in the low accelerator opening range, and smooth driving force control in the low accelerator opening range can be compensated.
[0013]
In the invention according to claim 2, the driving force control device calculates a target driving force curve on two-dimensional coordinates of the vehicle speed and the target driving force set for each predetermined accelerator opening lattice point on the accelerator opening lattice axis. , A target driving force corresponding to the vehicle speed is obtained, and the driving force of the vehicle is controlled to be the target driving force.
[0014]
By the way, the intersections of the target driving force curve for each of the planned accelerator opening lattice points on the two-dimensional coordinates and the running resistance curve of the vehicle described on the same two-dimensional coordinates are respectively in the vehicle speed axis direction indicating the vehicle speed. In view of the above, since the predetermined accelerator opening lattice point is determined so that the lower the opening degree of the accelerator opening lattice axis is, the closer the accelerator opening lattice point is,
Rather, in the low accelerator opening range, the driving force step between adjacent accelerator opening grid points becomes smaller, and in the low accelerator opening range where a delicate accelerator opening operation is performed, an accuracy corresponding to the accelerator operation is obtained. And smooth driving force control becomes possible.
[0015]
In the invention according to claim 3, when obtaining the target driving force,
Among the planned accelerator opening degree grid points, a target relating to the planned accelerator opening degree grid point on the high side and the planned accelerator opening degree grid point on the low side sandwiching the accelerator opening degree grid point corresponding to the current accelerator opening degree. From the driving force curve, a high-side target driving force and a low-side target driving force corresponding to the vehicle speed are obtained, respectively.
Since the high-side target driving force and the low-side target driving force are linearly interpolated to obtain the target driving force corresponding to the vehicle speed,
The target driving force of the vehicle can be obtained by a simple calculation.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a power train control device of a vehicle provided with a driving force control device according to one embodiment of the present invention. The power train of the vehicle is connected to a torque converter T / C of an engine 1 and a continuously variable transmission 2. It is configured by mutual tandem coupling.
[0017]
The output of the engine 1 is determined by the opening of a so-called electronically controlled throttle valve 4 that is not linked to the accelerator pedal 3 that the driver depresses, and the opening of the electronically controlled throttle valve 4 is controlled by a throttle actuator 5. I do.
The speed ratio of the automatic transmission 2 is determined by a speed control valve (not shown) responsive to a step motor 7 built in the control valve 6, and the engine speed from the torque converter T / C is shifted at this speed ratio. Output to the wheels.
[0018]
The opening degree control (engine output control) of the throttle valve 4 via the throttle actuator 5 and the shift control of the continuously variable transmission 2 via the step motor 7 are comprehensively controlled by a common controller 8.
The controller 8 includes a signal from an accelerator opening sensor 9 for detecting a depression amount (accelerator opening) APS of the accelerator pedal 3, a signal from a vehicle speed sensor 10 for detecting a vehicle speed VSP, and a gradient sensor for detecting a road surface gradient θ. 11 are input.
[0019]
The controller 8 executes the control programs shown in FIGS. 2 and 3 based on the input information to comprehensively control the engine 1 and the continuously variable transmission 2. FIG. 2 shows the main routine, and FIG. The subroutine for calculating the driving force will be described.
In steps 20 to 22 in FIG. 2, the accelerator opening APS, the vehicle speed VSP, and the road surface gradient θ are sequentially read, and then in step 23, a target driving force of a pure vehicle that does not consider the running resistance and the road surface gradient is calculated.
[0020]
The calculation of the target driving force is performed by executing the subroutine of FIG. 3 based on a map corresponding to the target driving force diagram as shown in FIG.
Here, the target driving force diagram of FIG. 4 will be described. In the diagram, the same target driving force curve as that of FIG. 5 is shown by a solid line, and a running resistance curve (road load line) R shown by a one-dot chain line is shown in FIG. / L is also shown.
As is well known, the running resistance curve (road road line) R / L is a curve connecting the running force of the vehicle and the driving force, and connecting the driving force just required to maintain the corresponding vehicle speed.
[0021]
In the present embodiment, the target driving force curve shown by a solid line at each APS grid point obtained by equally dividing the accelerator opening (APS) grid axis is shown in FIG. (The same curve as in FIG. 3), and sets a target driving force curve corresponding to another APS lattice point as shown by a two-dot chain line.
When such a target driving force curve is added, that is, when the above another APS grid point is set, the same as the target driving force curve for each APS grid point on the two-dimensional coordinates of the vehicle speed and the target driving force described on the target driving force curve. As shown in FIG. 4, the intersections of the vehicle with the running resistance curve R / L expressed on the two-dimensional coordinates are substantially equally spaced in the direction of the horizontal axis (vehicle speed axis) where the vehicle speed is scaled. The setting of the APS lattice point and the addition of the target driving force curve are performed.
[0022]
To explain the target driving force calculation routine of FIG. 3 executed by the controller 8, first, at step 30, among the scheduled APS lattice points on the APS lattice axis, the high-side APS lattice point immediately above the current accelerator opening APS. And the low-side APS lattice point immediately below.
Next, in step 31, a high-side target driving force corresponding to the vehicle speed VSP is searched from a target driving force map corresponding to the high-side APS lattice point.
Further, in step 32, a low-side target driving force corresponding to the vehicle speed VSP is searched from the target driving force map corresponding to the low-side APS lattice point.
[0023]
In step 33, the target driving force corresponding to the current accelerator opening APS is calculated by linearly interpolating between the high-side target driving force and the low-side target driving force.
[0024]
After calculating the target driving force corresponding to the current accelerator opening APS, the control is returned to step 24 in FIG. 2, where the running resistance of the vehicle is calculated,
Next, at step 25, the amount of increase or decrease of the vehicle driving force according to the road surface gradient θ (increase on an uphill road and decrease on a downhill road) is calculated.
Further, at step 26, the set value of the vehicle driving force is obtained by summing the target driving force, the running resistance, and the vehicle driving force increase / decrease corresponding to the road surface gradient,
Thereafter, in step 27, the engine 1 and the continuously variable transmission 2 are comprehensively controlled so that the vehicle driving force becomes the set value, for example, based on the concept described in Japanese Patent Application Laid-Open No. 7-172217.
[0025]
Here, the control of the engine 1 is control of the opening of the throttle valve 4 via the throttle actuator 5, and the control of the continuously variable transmission 2 is, of course, control of the shift via the step motor 6.
[0026]
According to this driving force control, as shown in FIG. 4, the intersections of the target driving force curve for each APS lattice point and the running resistance curve of the vehicle are substantially equally spaced when viewed in the vehicle speed axis direction. Having set points,
Even in the low accelerator opening range, the driving force step between adjacent accelerator opening lattice points does not increase, the target driving force obtained by linear interpolation between them becomes accurate, and the driving force control is aimed at In addition, the engine output torque does not suddenly change in response to a change in the accelerator opening even in the low accelerator opening range, and smooth driving force control in the low accelerator opening range can be compensated.
[0027]
As described above, instead of determining the APS grid points so that the intersections of the target driving force curve for each APS grid point and the running resistance curve of the vehicle are substantially equally spaced when viewed in the vehicle speed axis direction,
It is more preferable to determine the APS grid points such that the intersections are closer to the lower opening of the APS grid axis when viewed in the vehicle speed axis direction.
In this case, in the low accelerator opening region, the driving force step between adjacent accelerator opening lattice points is further reduced, and in the low accelerator opening region where a delicate accelerator opening operation is performed, the accelerator operation matches the accelerator operation. In addition, accurate and smooth driving force control becomes possible.
[0028]
Further, when calculating the target driving force corresponding to the current accelerator opening APS, as described above, the target driving force relating to the high-side APS lattice point immediately above and immediately below the current accelerator opening APS and the low-side APS lattice point. From the curve, determine the high-side target driving force and the low-side target driving force corresponding to the vehicle speed, respectively.
Since the target driving force is obtained by linearly interpolating the high-side target driving force and the low-side target driving force, the target driving force of the vehicle can be obtained by a simple calculation.
[0029]
In the above-described embodiment, as shown in FIG. 4, the accelerator pedal opening (APS) is used as a parameter, and the target driving force T is represented based on the target driving force T as a diagram relating to the vehicle speed VSP. We ’ve explained when to ask, but instead
In the case where the target driving force T is obtained based on the target driving force T representing the target driving force T as a diagram relating to the accelerator opening (APS) using the vehicle speed VSP as a parameter, the same action and effect are obtained by the same concept. Can be achieved.
In this case, a target driving force curve corresponding to another vehicle speed grid point based on the same concept is set as a target driving force curve for each vehicle speed grid point that equally divides the vehicle speed (VSP) grid axis,
The target driving force T is obtained from a target driving force curve on the two-dimensional coordinates of the accelerator opening (APS) and the target driving force T set for each of these predetermined vehicle speed grid points on the vehicle speed (VSP) grid axis.
[Brief description of the drawings]
FIG. 1 is an overall control system diagram of a vehicle power train including a driving force control device according to an embodiment of the present invention.
FIG. 2 is a flowchart showing a main routine of a driving force control program executed by a controller according to the embodiment.
FIG. 3 is a flowchart showing a subroutine for a target driving force calculation process in the driving force control program.
FIG. 4 is a target driving force characteristic diagram showing a target driving force map used in the embodiment in a diagram.
FIG. 5 is a target driving force characteristic diagram showing a general target driving force map used in the conventional driving force control device in a diagram.
[Explanation of symbols]
Reference Signs List 1 engine 2 continuously variable transmission 3 accelerator pedal 4 electronic control throttle valve 5 throttle actuator 6 control valve 7 step motor 8 controller 9 accelerator opening sensor 10 vehicle speed sensor 11 road surface gradient sensor

Claims

The target driving force corresponding to the vehicle speed is obtained from the target driving force curve on the two-dimensional coordinates of the vehicle speed and the target driving force set for each of the predetermined accelerator opening lattice points on the accelerator opening lattice axis, and the driving of the vehicle is performed. In a vehicle driving force control device that controls the force to be the target driving force,
The intersections of the target driving force curve for each of the planned accelerator opening degree grid points on the two-dimensional coordinates and the running resistance curve of the vehicle described on the same two-dimensional coordinates are respectively set in the vehicle speed axis direction indicating the vehicle speed. A driving force control device for a vehicle, wherein the predetermined accelerator opening degree grid points are determined so as to be substantially equally spaced when viewed.

The target driving force corresponding to the vehicle speed is obtained from the target driving force curve on the two-dimensional coordinates of the vehicle speed and the target driving force set for each of the predetermined accelerator opening lattice points on the accelerator opening lattice axis, and the driving of the vehicle is performed. In a vehicle driving force control device that controls the force to be the target driving force,
The intersections of the target driving force curve for each of the planned accelerator opening degree grid points on the two-dimensional coordinates and the running resistance curve of the vehicle described on the same two-dimensional coordinates are respectively set in the vehicle speed axis direction indicating the vehicle speed. A driving force control device for a vehicle, characterized in that the predetermined accelerator opening lattice points are determined so as to be closer to the lower opening side of the accelerator opening lattice axis.

3. The planned accelerator opening grid point on the high side and the planned accelerator on the low side sandwiching the accelerator opening degree grid point corresponding to the current accelerator opening degree among the planned accelerator opening degree grid points according to claim 1 or 2. From the target driving force curve related to the opening degree grid point, a high-side target driving force and a low-side target driving force corresponding to the vehicle speed are obtained, and the high-side target driving force and the low-side target driving force are linearly interpolated into the vehicle speed. A driving force control device for a vehicle, wherein the driving force control device is configured to obtain a corresponding target driving force.