**4. Conclusions**

Development of a single reduced mechanism was performed for SI engine geometries and configurations which required performing sensitivity analysis and reduction of the skeletal reaction mechanism using SENKIN, a sensitivity analysis module of CHEMKIN. The extraction of the sensitivity data from SENKIN using KINALC was then performed and a mechanism reduction was completed using the computational singular perturbation (CSP) method. This helped in minimizing the computational time by using fewer required reactions and species. A reduced mechanism was then constructed that validated engine performance and combustion parameters of incylinder pressure, heat release rate, and emissions for a range of equivalence ratios utilizing the low temperature pathway analysis.

A well-established surrogate, such as *iso-octane*, was selected for study as gasoline is a complex mixture of various compounds and hydrocarbons. The fundamental research provided the data and mechanistic understanding needed for the development of a library for detailed mechanisms that can be used to correctly predict engine performance parameters.

Understanding of the reduction techniques, and a practical reduced reaction mechanism for *spark-ignition engines* and combustion has been achieved through the above-mentioned methodology. Also, it has shown the need for using detailed chemistry in reactive flow problems which can help predict the combustion and engine performance parameters more accurately. To gain the necessary data and confidence for use of detailed chemistry, benchmarking was performed using the global and quasi-global mechanisms in a previous study.

*Numerical Simulations and Validation of Engine Performance Parameters Using Chemical… DOI: http://dx.doi.org/10.5772/intechopen.106536*
