抄録
コモンレール式K13C (L6/13liter)インタークーラターポエンジン(TIエンジン)のダンプ車搭載を目的に坂道発進性改善を行った。まず実車実験により、同格馬力の20L V8無過給エンジン(NAエンジン)とTIエンジンとを用い、坂道発進時の「粘り感」について検討した。次に発進操作を加味したシミュレーションにより、NAエンジン並の発進フィーリングを得る為のTIエンジンの極低速トルク特性を検討した。その結果、極低速回転域が、左下がりのトルクカーブで有りながらも、コモンレール方式がターポレスポンスに優れる特徴を生かす事に注目し、勾配に応じてガパナ特性を変える坂道発進補助装置を考案した。このシステムは、既存のESスタートシステムとエンジンガバナを協調させ、半クラッチ中は適切なアイドル回転とガバナ感度を選択し、エンジン回転落ちを抑止する。そして発進後のシフトアップ時に従来の特性に戻す。この新システムを搭載したK13CダンプトラックはNAエンジンと同等の発進性を備える事が出来た。
This paper describes the improvement for starting ability of the latest Hino K13C (L6/13liter) turbo charged and intercooled heavy duty diesel engine (T.I engine) with a common-rail fuel injection equipment. Generally T.I engine is well known as it has a good perfbrmance for the fuel consumption and the emission comparing to naturally aspirated V8 engine (N.A engine) but the slope starting ability. So a dump truck fixed TI eneine has to be also fixed a multi speed transmission. Therefore, without the multi speed transmission, the dump track fixed TI engine is developed by this study. At first the robustness feeling during the clutch engagement at slope starting is investigated by the vehicle experiment with the same horse powered T.I engine and the 20 litter N.A V8 engine. And secondly, low speed engine torque performance is studied by the simulation model considered driver s operation of the accelerator and the clutch at the slope starting. Because the turbo response, which a common-rail fuel injection equipment brings, is rather better than one of current Tl engine, this new TI engine is considered as NA engine with the engine property of torque curve lower at left. This simulation shows some solutions of the eneine torque design in order to keep the same robustness feeling as NA engine at the clutch fully engaged. Among these ideas, a slope starting assistant system, by which the engine performance is controlled according to the angle of inclination, is developed. This new system is working with the collaboration of Easy & Safety starting system and the Engine govemor control ECU. The angle of inclination is detected during stopping on the slope. And simultaneously this svstem selects temporally govemor performance of the idling speed and the sensitivity of the engine speed control. Just before the clutch is half engaged, the govemor performance is switched to this temporal condition so as to keep the engine speed constant at the clutch fully engaged. Finally this temporal performance is switched to normal condition again when a driver shifts up. With this new system, the good slope starting ability as same as that of NA engine can be achieved for the dump truck fixed K13C engine.
