A Surrogate Fuel Formulation Approach for Real Transportation Fuels with Application to Multi-Dimensional Engine Simulations

A Surrogate Fuel Formulation Approach for Real Transportation Fuels with Application to Multi-Dimensional Engine Simulations

Type	Report
Author	Xingyuan Su
Author	Youngchul Ra
URL	http://papers.sae.org/2014-01-1464/
Abstract	Real fuels like gasoline and diesel, are mixtures of thousands of different hydrocarbons. For multidimensional engine applications, numerical simulations of combustion of real fuels with all of the hydrocarbon species included exceeds present computational capabilities. Consequently, surrogate fuel models are typically used. A surrogate fuel model should approximate the essential physical and chemical properties of the real fuel. Authors present a novel methodology for the formulation of surrogate fuel models based on local optimization and sensitivity analysis technologies. They consider several important fuel properties are considered. Under the physical properties, they focus on volatility, density, lower heating value (LHV), and viscosity, while the chemical properties relate to the chemical composition, hydrogen to carbon (H/C) ratio, and ignition behavior. They assign an error tolerance to each property for convergence checking. In addition, they assign a weighting factor to each property indicating its individual importance among all properties considered; the overall quality of the surrogate fuel model is controlled by a weighted error tolerance. They observe that the solver can find an accurate surrogate fuel model for a low-cetane diesel fuel with 11 iterations. They validate the surrogate fuel model using a multi-dimensional engine simulation operated under a low temperature combustion (LTC) condition against the available experimental data. Results show that the proposed surrogate fuel model can accurately predict the overall combustion process and emissions, simultaneously; while the single component model is unable to predict the combustion process and emissions in the LTC condition for the low cetane diesel fuel.
Report Number	2014-01-1464