摘要
在一台火花点火天然气发动机上开展了不同掺氢比和EGR率下发动机性能和排放的试验研究。研究结果表明:引入EGR后发动机输出功率下降,但掺氢可以提高大EGR工况下发动机的输出功率。有效热效率随EGR率的增大呈现先升高后降低的趋势;小EGR率下,有效热效率随掺氢比的增加而降低,而大EGR率下,有效热效率随掺氢比的增大而升高。天然气掺氢后NOx排放增加,EGR引入使NOx排放降低,这种降低作用在大掺氢比下更显著。因此,相对于小EGR率工况,大EGR率工况下天然气掺氢表现出更好的性能和排放效果。HC排放随EGR率的增大而增加,随掺氢比的增加而降低。CO和CO2都随EGR率的增加变化不大,随掺氢比的增加而降低。研究表明,天然气掺氢结合EGR可实现火花点火发动机高效低污染燃烧,并能满足欧Ⅳ排放标准。
An experimental investigation on the influence of different hydrogen fractions and EGR rates on the performance and emissions of a spark-ignition engine was conducted. The results show that EGR utilization decreases the engine power output. However, hydrogen addition can increase the power output at large EGR operation. Thermal efficiency shows an increasing trend at small EGR rate and a decreasing trend with further increase of EGR rate. In the case of small EGR rate, thermal efficiency is decreased with the increase of hydrogen fraction ; while in the case of large EGR rate, thermal efficiency is increased with increasing of hydrogen fraction. For a specified hydrogen fraction, NOx concentration is decreased with the increase of EGR rate and this effectiveness becomes more obviously at high hydrogen fraction. HC emission is increased with the increase of EGR rate and it decreases with the increase of hydrogen fraction. CO and CO2 emissions show little variation with EGR rate, but they decrease with the increase of hydrogen fraction. The study shows that natural gas-hydrogen blend combined with EGR can realize low emissions for the spark-ignition engine.
出处
《内燃机学报》
EI
CAS
CSCD
北大核心
2009年第5期385-394,共10页
Transactions of Csice
基金
国家重大基础研究计划项目(2007CB210006)
国家自然科学基金重点项目(50636040)
