Modelling cycle to cycle variations in an SI engine with detailed chemical kinetics
Modelling cycle to cycle variations in an SI engine with detailed chemical kinetics
复制标题
DOI：
10.1016/j.combustflame.2010.08.006
复制
发表时间：
2011
影响因子：
4.4
通讯作者：
Jonathan E. Etheridge;S. Mosbach;M. Kraft;Hao Wu;N. Collings
中科院分区：
文献类型：
--
作者：
Jonathan E. Etheridge;S. Mosbach;M. Kraft;Hao Wu;N. Collings
本文介绍了火花点火（SI）发动机循环变动（CCV）的实验结果和一个新的计算模型。为了模拟点燃式发动机的燃烧过程，将一个用于研究均质充量压燃（HCCI）燃烧的随机反应器模型（SRM）扩展为火花点火、火焰传播和火焰终止子模型。该模型包含一个详细的化学机制，但相对较短的计算时间实现。假设火焰前锋是球形的，并以火花位置为中心，并考虑了活塞顶和活塞碗的几何形状。通过模拟一台燃用异辛烷的单缸研究用发动机的压力分布和排放，验证了该模型的有效性。关键参数的影响进行了研究。本文给出了四缸自然吸气汽油点燃式发动机循环波动的试验结果。然后将该模型与GT-Power（一种一维发动机仿真工具）耦合，该工具用于在多循环模拟期间模拟呼吸事件。这允许研究峰值压力的周期波动。然后研究了不同循环产生的一氧化氮（NO）排放的来源和大小。结果发现，与具有较慢燃烧速率的循环相比，较快的燃烧循环导致增加的NO排放，并且与循环后期相比，在燃烧的早期阶段产生更多。大部分NO是在燃烧开始后通过热机制产生的。
This paper presents experimental results and a new computational model that investigate cycle to cycle variations (CCV) in a spark ignition (SI) engine. An established stochastic reactor model (SRM) previously used to examine homogeneous charge compression ignition (HCCI) combustion has been extended by spark initiation, flame propagation and flame termination sub-models in order to simulate combustion in SI engines. The model contains a detailed chemical mechanism but relatively short computation times are achieved. The flame front is assumed to be spherical and centred at the spark location, and a pent roof and piston bowl geometry are accounted for. The model is validated by simulating the pressure profile and emissions from an iso-octane fuelled single cylinder research engine that showed low CCV. The effects of key parameters are investigated. Experimental results that show cycle to cycle fluctuations in a four-cylinder naturally aspirated gasoline fuelled SI engine are presented. The model is then coupled with GT-Power, a one-dimensional engine simulation tool, which is used to simulate the breathing events during a multi-cycle simulation. This allows an investigation of the cyclic fluctuations in peak pressure. The source and magnitude of nitric oxide (NO) emissions produced by different cycles are then investigated. It was found that faster burning cycles result in increased NO emissions compared with cycles that have a slower rate of combustion and that more is produced in the early stages of combustion compared with later in the cycle. The majority of NO was produced via the thermal mechanism just after combustion begins.