Applying Representative Interactive Flamelets (RIF) with Special Emphasis on Pollutant Formation to Simulate a DI Diesel Engine with Roof-Shaped Combustion Chamber and Tumble Charge Motion

Combustion and pollutant formation in a new recently introduced Common-Rail DI Diesel engine concept with roof-shaped combustion chamber and tumble charge motion are numerically investigated using the Representative Interactive Flamelet concept (RIF).

A reference case with a cup shaped piston bowl for full load operating conditions is considered in detail. In addition to the reference case, three more cases are investigated with a variation of start of injection (SOI).

A surrogate fuel consisting of n-decane (70% liquid volume fraction) and α-methylnaphthalene (30% liquid volume fraction) is used in the simulation. The underlying complete reaction mechanism comprises 506 elementary reactions and 118 chemical species. Special emphasis is put on pollutant formation, in particular on the formation of NO_x, where a new technique based on a three-dimensional transport equation within the flamelet framework is applied.

For all cases simulation results are compared to experimental data that has been obtained using real diesel fuel. The agreement between simulation and experiment is found to be very good.