The development of highly efficient combustion concepts for internal combustion engines requires a suitable development methodology. In recent years, the LEC has created LDM (LEC Development Methodology), which is based on the intensive interaction between simulation and experimental investigations on single cylinder research engines. As new engine concepts are developed, many operating parameters are first defined and optimized with a 1D multicylinder engine model. This model illustrates the full complexity of the engine with its geometry, turbocharging and combustion parameters. The design of experiments (DoE) method is used in connection with 1D simulation to find the optimal engine configuration as well as parameters related to the combustion process, i.e. valve timing, compression ratio, ignition timing, excess air ratio. The maximum engine efficiency is found by taking into account the boundary conditions (brake mean effective pressure, turbocharger efficiency), where NOx level and knock limit are constraints.