Dynamic Burn Rate Modeling for the 1D Simulation of a GDI Engine in Homogeneous and Stratified Operation Mode

The paper addresses the characterization of global burn rates for gasoline fueled internal combustion engines applying direct injection and mixture stratification.

Effects of variations in engine speed and load as well as combustion mode (early vs. late fuel injection and mixture stratification) on the global burn rate are discussed. A simple model is suggested which quantitatively describes the dynamic response of burn rate coefficients to changes in operating conditions.

For this purpose, burn rates from part load operating conditions (homogeneous and stratified) are deduced from experimental data. Results from single and two-zone approaches are contrasted and the assumptions in this context are highlighted. In order to provide global burn rate function parameters also for the stratified operation, an extension to the well established Vibe function is introduced.