Ấn phẩm:
Effects of split injection, oxygen enriched air, and heavy EGR rate on soot emissions in a diesel engine
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Tóm tắt
The effects of split injection, oxygen enriched air, and heavy exhaust gas recirculation (EGR) on soot emissions in a direct injection diesel engine are studied using the KIVA-3V code.
When split injection is applied, a dwell time between two injections causes the decrease in local temperature and the fuel-rich area in the flame, which leads to the significantly decrease in precursor formation. Thus, the soot formation in split injection is decreased compared to single injection. The second injection of fuel into a cylinder results in two separate stoichiometric zones which help increase soot oxidation. As a result of soot formation decrease and soot oxidation increase, the soot emissions are decreased.
When oxygen enriched air is applied together with split injection, a higher concentration of oxygen results in more burned fuel and higher temperature in the cylinder. The increase in temperature promotes the growth reaction of acetylene with soot, however it does not enhance the acetylene formation during the second injection of fuel. As more acetylene is consumed in the growth reaction with soot, the concentration of acetylene in the cylinder is decreased, which leads to a decrease in soot formation. With an increase in soot oxidation caused by split injection and a more decrease in soot formation caused by oxygen enrichment, the soot emissions are decreased significantly, with a small penalty in NOx emissions.
To take the full advantages of oxygen enriched air in reduction of soot and of EGR in reduction of NOx, a combination of split injection with high concentration of oxygen and high EGR ratio is used. This combination shows the best results in terms of diesel emissions. In this study, the split injection scheme of 75.8.25 with an oxygen concentration of 23% in volume and an EGR ratio of 30% shows a 45% reduction in soot emissions with the same NOx emissions as in single injection.
This study shows that with a suitable combination of engine technologies, the soot emissions of a diesel engine can be reduced significantly without penalty in NOx emissions
Mô tả
107 p.
Tác giả
Nguyễn, Lê Duy Khải.
Người hướng dẫn
Huh, Kangyul
Hwang, Youngkyu
Kim, Hongsuk
Kwon, Ohchae
Sung, Nakwon
Hwang, Youngkyu
Kim, Hongsuk
Kwon, Ohchae
Sung, Nakwon
Nơi xuất bản
Nhà xuất bản
Sungkyunkwan University
Năm xuất bản
2009
ISSN tạp chí
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Từ khóa chủ đề
Mechanical engineering. , Cơ khí.