摘要
结合柴油机燃用二甲醚HCCI燃烧与缸内直喷燃烧各自的优点,提出了柴油机燃用二甲醚气道—气缸喷射复合燃烧方式。在一台改造过的2135柴油机上,通过调整预混合率和直喷供油提前角以及进气燃料设计对复合燃烧进行了研究。结果表明,燃烧过程包括HCCI燃烧和缸内喷雾的预混及扩散燃烧,燃烧方式主要受预混合率的影响而呈现不同的放热特征。采用适当的预混合率和直喷供油提前角,与HCCI燃烧比,复合燃烧在保持NOx基本不变的条件下有效地拓宽了发动机工况范围,同时降低了HC和CO排放。通过在DME中添加LPG降低燃料十六烷值来控制HCCI的燃烧,可降低NOx排放,在大预混合率下,发动机经济性得到改善。
Combining the advantages of HCCI combustion and in-cylinder direct-injection combustion for a diesel engine fueled with DME, a new concept combustion system, compound charge compression ignition （CCCI） combustion system by port aspiration and in-cylinder direct injection of DME, was proposed. A diesel engine was modified to carry out this test, and the combustion and emission characteristics were studied under different premixed fuel ratios and fuel delivery advance angle as well as port fuelling design. The results showed that CCCI combustion process included the HCCI combustion, and the spray controlled premixed and diffusion combustion. It presents different combustion characteristics under different premixed fuel ratios. Comparing with HCCI combustion mode, under an appropriate premixed fuel ratio and fuel delivery advance angle, CCCI combustion can extend the operating range with low NOx, HC and CO emissions. To control the ignition and combustion phase of HCCI, the effect of LPG addition to DME fuel was evaluated. As a result, NOx emission was decreased and fuel economy was improved at mediumload with high premixed fuel ratio and at high-load with mixing LPG.
出处
《内燃机学报》
EI
CAS
CSCD
北大核心
2008年第3期193-199,共7页
Transactions of Csice
基金
高校博士点基金(20050248013)
关键词
二甲醚
复合燃烧
HCCI
预混合率
燃烧控制
Dimethyl ether
CCCI combustion
HCCI
Premixed fuel ratio
Combustion control
