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In this study, experimental results of homogeneous charge compression ignition HCCI of n-butane in a single shot machine are presented. N-butane measurements are compared with a multizone model. Individual zones are calculated using a perfectly stirred reactor and Chemkin chemistry. The influence of temperature before combustion on heat release rate and duration of combustion is shown in a sensitivity analysis. As a perfect homogeneous temperature and fuel distribution are difficult to establish under experimental conditions, deviations from perfect homogeneity are shown. The influence of a hot surface in the cylinder head in terms of heat release rate and ignitability is examined. Further, dual fuel injections of n-butane and diesel are studied to trigger the n-butane ignition with a defined start of combustion.

Numerical and experimental investigations are presented with regard to homogeneous-charge-compression-ignition for two different fuels. N-heptane and n-butane are considered for covering an appropriate range of ignition behaviour typical for higher hydrocarbons. One fuel is closer to diesel (n-heptane), the other closer to gasoline ignition properties (n-butane). Butane in particular, being gaseous under atmospheric conditions, is used to also guarantee perfectly homogenous mixture composition in the combustion chamber. Starting from detailed chemical mechanisms for both fuels, reaction path analysis is used to derive reduced mechanisms, which are validated in homogeneous reactors. After reduction, reaction kinetics is coupled with multi zone modeling and 3D-CFD through the Conditional Moment Closure (CMC) approach in order to predict autoignition and heat release rates in an I.C. engine. Multi zone modeling is used to simulate port injection HCCI technology with n-butane.