Abstract To comply with reinforced emission regulations for harmful exhaust gases, including carbon dioxide ($ CO_{2} $) emitted as a greenhouse gas, improved technologies for reducing $ CO_{2} $ and fuel consumption are being developed. Stable lean combustion, which has the advantage of improved fuel economy and reduced emission levels, can be achieved using a sprayguided-type direct-injection (DI) combustion system. The system comprises a centrally mounted injector and closely positioned spark plugs, which ensure the combustion reliability of a stratified mixture under ultra-lean conditions. The aim of this study is to investigate the combustion and emission characteristics of a lean-burn gasoline DI engine. At an excess air ratio of 4.0, approximately 23% improvement in fuel economy was achieved through optimal event timing, which was delayed for injection and advanced for ignition, compared to that under stoichiometric conditions, while $ NO_{x} $ and HC emissions increased. The combustion characteristics of a stratified mixture in a spray-guided-type DI system were similar to those in DI diesel engines, resulting in smoke generation and difficulty in three-way catalystutilization. Although a different operating strategy might decrease fuel consumption, it will not be helpful in reducing $ NO_{x} $ and smoke emissions; therefore, alternatives should be pursued to achieve compliance with emission regulations.
Evaluation and visualization of stratified ultra-lean combustion characteristics in a spray-guided type gasoline direct-injection engine
2014
Article (Journal)
English
BKL: | 55.20$jStraßenfahrzeugtechnik / 55.20 Straßenfahrzeugtechnik |
British Library Online Contents | 2014
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