成層自着火燃焼とそれを適用した二輪車用二行程ガソリン機関に関する研究

フォーマット:

学位論文

責任表示:

西田, 憲二

言語:

日本語

出版情報:

群馬大学工学研究科, 2010-03

著者名:

西田, 憲二  

開始ページ:

1

終了ページ:

150

バージョン:

AM

概要:

application/pdf<br />Thesis or Dissertation<br />ついて実験的検討を行った．その結果，成層自着火燃焼は均一給気自着火燃焼と比べ，自着火領\n域は低速低負荷へ大幅に拡大できることが明らかとなった．また，燃料消費率とNOx エミッショ\nンはほぼ同等で，HC エミッションは最大20 %低減した．これらより，所期の成層自着火燃焼コ\nンセプトは実験的に検証された．しかしながら，アイドリング運転など低速の極低負荷 … 域では自\n着火できず，不整燃焼の完全な克服にはいたらなかった．\nもう一つは成層自着火燃焼を適用した新しい二行程ガソリン機関に関する研究である．不整燃\n焼を克服するために4 種類の燃焼形態で構成される二行程ガソリン機関を考案した．この機関コ\nンセプトは，高負荷域は均一給気火花点火，低中負荷域は均一給気自着火，低速低負荷域は成層\n自着火，アイドリング域は成層給気火花点火となるように，機関の速度と負荷に応じて燃焼を使\nい分けるというものである．均一給気自着火と成層給気火花点火との中間領域に成層自着火を配\n置することで，自着火と成層給気火花点火の燃焼移行がスムーズに制御可能になると考えた．こ\nの供試機関は，常用負荷域で不整燃焼のない運転を可能とした．さらに，車両燃費改善の可能性\nを評価するために，機関実験データをもとに小型モーターサイクルへ適用した場合のECE-R40 モ\nード燃費の試算を試みた．その結果，ECE-R40 モード燃費率はベースとなる四行程ガソリン機関\nと比べ，高トルクを活かしたダウンサイジングとの併用により約20 %の改善が見込まれた．\nTwo-stroke gasoline auto-ignition engine technology with direct-injection system is expected as an\nengine technology of improving the fuel economy of vehicles. However, the irregular combustion occurs at\nlow-speed and low-load. It is the most serious problem for practical use. This study presents a new concept\nof auto-ignition combustion and its application to a two-stroke gasoline engine for solving the problem of\ntwo-stroke gasoline auto-ignition engine. This paper consists of two studies.\nFirst study presents a new auto-ignition concept, i.e. Stratified-Charge Auto-Ignition (SCAI) concept,\nwhich focuses on the relationship between gas temperature distribution and mixture formation in the combustion\nchamber. Visualization of the direct-injection spray formation was firstly conducted, and then the combustion\nchamber geometry was determined by using CFD simulation, to generate the favorable mixture distribution at\nthe hot spot in the combustion chamber. The experimental results revealed that SCAI remarkably extended its\noperating area toward lower speed and lower load compared with that of the conventional homogeneous-charge\nauto-ignition (HCAI). And HC emission decreased by 20 % while the fuel consumption and NOx emission could\nremain the same level in comparison with those of the conventional HCAI under the same load. However, the\nexperimental engine could not maintain auto-ignition combustion at an idle, and could not conquer the irregular\ncombustion completely.\nSecond study presents a new concept of two-stroke gasoline engine applying the stratified-charge\nauto-ignition. The new concept engine has been designed and studied experimentally for improving fuel\neconomy of vehicles. The engine concept adopts four different combustion modes according to the engine\noperating condition, i.e. homogeneous-charge spark-ignition for high-load range, homogeneous-charge\nauto-ignition for medium to low-load range, stratified-charge auto-ignition for low-speed and low-load\nrange, and stratified-charge spark-ignition for the idling. The new concept two-stoke gasoline experimental\nengine made operating possible free from irregular combustion throughout the operating range in common\nuse. In the case of a small motorcycle application, great improvements in the fuel economy and exhaust\nemissions were estimated from the experimental results. The estimate for improvement rate of ECE-R40\nmode fuel economy was approximately 20 % for the downsized engine compared with the four-stroke\ngasoline spark-ignition engine.<br />学位記番号：工博甲383 続きを見る