Congruent modelling and experimental investigation to gain insight into the transients associated with the hybridized SI-HCCI-SI engine operation

这项工作的主要目的是为了更好地了解未来先进内燃机策略的运行情况。这种理解对于开发高效、超低排放的发动机以满足环境法规至关重要。例如，欧洲汽车制造商承诺到2008年将车队的平均二氧化碳排放量减少到每公里140克，到2012年预计将减少到每公里120克。混合SI-HCCI-SI发动机技术是实现这些目标的潜在解决方案，可以改善燃油消耗，开发接近零排放的车辆。这种混合动力操作可以使英国每年减少约70万公吨的二氧化碳水平（对于代表性的2.0升汽油发动机尺寸）。此外，在HCCI运行模式下，该技术可以实现氮氧化物排放减少99% （c.f.si）和几乎没有烟尘排放的好处。除了实验研究，计算模型已经被研究团体用来深入了解与这种混合动力发动机运行相关的瞬态。然而，现有的模型本质上是经验性的，依赖于实验的概况。这也可能是缺乏数值分析来研究复杂的动态瞬态现象对调节排放的影响的原因。提出的研究包括开发一种先进的预测现象学模型来模拟SI-HCCI-SI发动机瞬态。该模型将根据测量结果进行验证，并在本文提出的一些新实验的帮助下进一步改进。提出的工作包括三个部分：1)建立一个新的计算模型来解释瞬态过程中自发多点点火（hcci -类）和预混火焰传播（si -类）。该模型包括详细的化学动力学描述，并说明了成分和温度的不均匀性，因此有助于理解瞬态过程对CO， HC和NOx排放的影响。2)通过开展具有代表性的复杂瞬态现象操作条件的高性价比实验来理解类瞬态操作。这些测量也将用于验证公式模型。3)针对完全可变气门正时（FVVT）能力的SI-HCCI-SI瞬态发动机运行的实验结果进行模型验证。总的来说，这种一致的实验和建模方法涉及在学术研究和工业合作伙伴之间分享技术诀窍和专业知识，旨在实现超低排放发动机的性能。

The main aim of the work is to gain a better insight into the operation of near-future advanced internal combustion engine strategies. Such understanding is vital for the development of high-efficiency, ultra-low-emissions engines to meet environmental regulations. For example, the European automotive manufacturers have committed to reduce fleet average CO2 emissions to 140g/km by 2008, with 120g/km projected by 2012. Hybridized SI-HCCI-SI engine technology is a potential solution towards achieving such targets in improving fuel consumption and developing near-zero emissions vehicles. Such hybridized operation could enable a reduction in UK CO2 levels of ~0.7million metric tons per annum (for a representative 2.0 l gasoline engine size). Furthermore, the benefits of 99% reduction (c.f. SI) in NOx emissions and virtually no soot emissions during HCCI mode of operation can be realised with this technology. In addition to experimental research, computational modelling has been utilized by the research community to gain insight into the transients associated with such a hybridized engine operation. However, the existing models are empirical in nature and rely on profiles from experiments. This may also be the reason for the absence of numerical analysis to investigate the effect of the complex and dynamic transient phenomena on the regulated emissions. The proposed research involves the development of an advanced, predictive phenomenological model to simulate the SI-HCCI-SI engine transients. The model will be validated against measurements and further improved with the help of some new experiments suggested in this proposal. The proposed work comprises of three parts: 1) Development of a novel computational model to account for spontaneous multi point ignition (HCCI-like) as well as premixed flame propagation (SI-like) during the transients. The model includes detailed chemical kinetics description and accounts for inhomogeneities in composition and temperature, thus proving beneficial in understanding the impact of the transient processes on CO, HC and NOx emissions. 2) Understanding transient-like operation by carrying out cost-effective experiments involving operating conditions representative of the complex transient phenomena. These measurements will also be used in validating the formulated model. 3) Model validation against experimental results obtained from fully variable valve timing (FVVT) capable SI-HCCI-SI transient engine operation. Overall, this congruent experimental and modelling approach involves sharing the know-how and expertise between academic research and industrial partners aimed at realising ultra-low emissions engine performance.