Influence of swirl and tumble motion inside the combustion chamber of a compression ignited engine on vertices formation

Abstract

In modern compression ignited engines, one of the key innovative directions is optimization of the burn process especially to reduce emissions. This optimization can be done by ensuring a better air-fuel mixture. To answer this problem, in the current paper, the authors analysed the vertices formation and velocity inside the combustion chamber in thirteen cases, by using numerical analysis (AVL FIRE Software), to generate pure tumble motion, pure swirl motion, no in-cylinder motion of the air, and other combinations on tumble and swirl motion. The cases that were chosen combine 0%, 50%, 70% and 100% tumble and swirl motion. The greatest velocity of the in-cylinder air motion was noted when a 100%tumble and 50% swirl motion was induced (77.2 m/s at 736 degrees CA), while the smallest velocity was noted at 100% swirl and 0% tumble (71.07 m/s at 736 degrees CA). Because of the different induced motions, the vertices that form inside the combustion chamber have a great influence on air-fuel mixture and implicitly on emissions.