In the competition for the powertrain of the future the internal combustion engine faces tough challenges. Reduced environmental impact, higher mileage, low cost and new technologies are required to maintain its global position in public and private mobility. For decades researchers have been investigating the Homogeneous Charge Compression Ignition (HCCI) promising higher efficiency due to the rapid combustion and therefore low exhaust gas temperatures. Consequently there is no need for a rich mixture to cool the turbocharger under high load. As the combustion does not have a distinguished flame front it is able to burn very lean mixtures, reducing HC and CO emissions. However, until recently, HCCI was considered to be only applicable as a part load process. The 3D engine development tool QuickSim which has been developed at the FKFS in Stuttgart is able to simulate the entire flow path of the engine, including conventional and HCCI combustion. In a recent project with the German Aerospace Center (DLR) it was possible to calibrate the parameters of the auto-ignition model using a highly variable free piston linear generator. This paper addresses the potential of virtual engine development in the creation of a new combustion process for series engines. The described process is called Spark-Assisted Compression Ignition (SACI). It utilizes a pre-chamber sparkplug to initialize and control the auto-ignition. This prevents accidental combustion and also ensures an auto-ignition less dependent on the environment and transient conditions, while maintaining the efficiency and emission advantages of conventional HCCI. Further information like simulation results and supporting measurement data will be displayed in the respective paper.