Influence of In-cylinder Tumble on Gasoline Engine Performance with EGR
Author(s): HAN Lin-pei, HONG Wei, YANG Jun-wei, YANG Wan-li, XIE Fang-xi, SU Yan
Pages: 38-44
Year: 2014 Issue: 1
Journal: Vehicle Engine
Keyword: gasoline engine; tumble ratio; EGR; combustion; emission; ignition timing;
Abstract: For a 1 .8 L gasoline engine ,the influences of in-cylinder tumble on EGR engine combustion and emission were re-searched by the CFD Fire software and the optimization and match of ignition timing and tumble ratio and the performance com-parison of different initial tumble positions were further analyzed .The calculated results show that high tumble ratio can im-prove combustion and compensate the loss caused by EGR from the perspective of combustion .Compared with the combustion without tumble ,the combustion with 2 .5 tumble ratio can shorten 90% fuel combustion duration of 5% ,15% and 25% EGR ratio by 31% ,31 .7% and 34 .8% respectively .The enhanced tumble motion can reduce HC emission of EGR gasoline engine , but increase NOx emission .The maximum mean indicated pressures of different tumble ratios correspond to different ignition angles and the value of low tumble ratio at 5% EGR ratio is higher than that of high tumble ratio .The different initial tumble positions can not continue for a long time and the tumble centre will move to the centre of combustion chamber soon ,which has little influence on combustion performance .
Pages: 38-44
Year: 2014 Issue: 1
Journal: Vehicle Engine
Keyword: gasoline engine; tumble ratio; EGR; combustion; emission; ignition timing;
Abstract: For a 1 .8 L gasoline engine ,the influences of in-cylinder tumble on EGR engine combustion and emission were re-searched by the CFD Fire software and the optimization and match of ignition timing and tumble ratio and the performance com-parison of different initial tumble positions were further analyzed .The calculated results show that high tumble ratio can im-prove combustion and compensate the loss caused by EGR from the perspective of combustion .Compared with the combustion without tumble ,the combustion with 2 .5 tumble ratio can shorten 90% fuel combustion duration of 5% ,15% and 25% EGR ratio by 31% ,31 .7% and 34 .8% respectively .The enhanced tumble motion can reduce HC emission of EGR gasoline engine , but increase NOx emission .The maximum mean indicated pressures of different tumble ratios correspond to different ignition angles and the value of low tumble ratio at 5% EGR ratio is higher than that of high tumble ratio .The different initial tumble positions can not continue for a long time and the tumble centre will move to the centre of combustion chamber soon ,which has little influence on combustion performance .
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