Effect of exhaust gas recirculation on the cycle-to-cycle variations in a natural gas spark ignition engine
Effect of exhaust gas recirculation on the cycle-to-cycle variations in a natural gas spark ignition engine
复制标题
DOI：
10.1016/j.applthermaleng.2011.03.018
复制
发表时间：
2011-10
影响因子：
6.4
通讯作者：
A. Sen;S. K. Ash;Bin Huang;Zuo-hua Huang
中科院分区：
文献类型：
--
作者：
A. Sen;S. K. Ash;Bin Huang;Zuo-hua Huang
研究了天然气火花点火发动机排气再循环（EGR）对燃烧循环变动（CCV）的影响。发动机以2000 rpm运行，并使用化学计量的燃料-空气混合物。EGR水平从0%变为5%、10%、15%和20%。对于每个EGR水平，连续小波变换被用来分析的时间序列的指示平均有效压力（IMEP）超过200个周期。的CCV的主要振荡模式的识别和发动机循环，这些模式可能会持续划定。结果表明，IMEP的CCV发生在多个时间尺度上，并表现出复杂的动态。在没有EGR的情况下，主要观察到高频间歇性波动。随着EGR水平的增加，更持久的低频变化倾向于发展。此外，光谱功率的增加与EGR水平的增加。在EGR水平为20%时，发现光谱功率显著增加，表明EGR对增加CCV具有显著效果。了解变化的主要模式对于开发有效的控制策略以在存在EGR的情况下降低CCV和改善发动机性能可能是有用的。
This study investigates the effect of exhaust gas recirculation (EGR) on the cycle-to-cycle variations (CCV) in combustion in a natural gas spark ignition engine. The engine is operated at 2000 rpm and a stoichiometric fuel-air mixture is used. The EGR level is changed from 0% to 5%, 10%, 15%, and 20%. For each EGR level, a continuous wavelet transform is used to analyze the time series of the indicated mean effective pressure (IMEP) over 200 cycles. The dominant oscillatory modes of the CCV are identified and the engine cycles over which these modes may persist are delineated. The results reveal that the CCV of the IMEP occur on multiple timescales and exhibit complex dynamics. With no EGR, mainly high frequency intermittent fluctuations are observed. As the EGR level is increased, more persistent low frequency variations tend to develop. In addition, the spectral power increased with an increase in the EGR level. At the EGR level of 20%, the spectral power is found to increase significantly indicating that EGR has a pronounced effect on increasing the CCV. Knowledge of the dominant modes of variability may be useful to develop effective control strategies for reducing the CCV and improving engine performance in the presence of EGR.