COMBUSTION CHAMBER STRUCTURE FOR ENGINE

To provide a combustion chamber structure for an engine using SI combustion and SPCCI combustion in combination for maintaining both a tumble flow and a swirl flow until a late period for a compression stroke.SOLUTION: A combustion chamber of the engine has a geometric compression ratio set to be 15...

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Main Authors NISHI FUTA, HONDA YUYA, INOUE ATSUSHI, KONO MICHIHARU, IMAMURA SATOSHI, NAKAHARA KOJI, MATSUMOTO KOTA, FUKUMA MASANARI
Format Patent
LanguageEnglish
Japanese
Published 04.06.2020
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Summary:To provide a combustion chamber structure for an engine using SI combustion and SPCCI combustion in combination for maintaining both a tumble flow and a swirl flow until a late period for a compression stroke.SOLUTION: A combustion chamber of the engine has a geometric compression ratio set to be 15 or over to enable the SPCCI combustion. A crown surface 50 of a piston 5 includes a cavity 51 recessed in a bowl shape, and an F side protruded part 52F and an R side protruded part 52R protruded in an outer periphery region of the cavity 51 in a cylinder axial direction and having a mountain shape along the pent roof shape of the ceiling surface of the combustion chamber. B/L is set in a range of being greater than 1.0 and equal to or smaller than 1.52, where L is a space between both the protruded parts 52F, 52R and B is the diameter of the piston 5.SELECTED DRAWING: Figure 12 【課題】SI燃焼とSPCCI燃焼とを併用する同エンジンにおいて、タンブル流及びスワール流の双方を圧縮行程後期まで維持する。【解決手段】エンジンの燃焼室は、幾何学的圧縮比が15以上に設定され、SPCCI燃焼が可能とされている。ピストン5の冠面50には、椀状に凹設されてなるキャビティ51と、キャビティ51の外周領域において気筒軸方向に突設され、燃焼室天井面のペントルーフ形状に沿った山型形状を有するF側凸部52F及びR側凸部52Rが備えられている。両凸部52F、52Rの間隔をL、ピストン5の直径をBとするとき、B/Lが1.0より大きく1.52以下の範囲に設定されている。【選択図】図12
Bibliography:Application Number: JP20180215600