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

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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.