1D simulation has significantly supported the process of developing a diesel ignited high-pressure gas direct injection combustion concept, thus facilitating promising investigations at the SCE. It has been applied to a variety of tasks such as designing the media supply system, pre-optimizing engine operating parameters and developing the safety concept discussed in this paper. Application depends on two simulation models in particular: one validated MCE model and one SCE model enhanced in the course of the concept design phase. Since the MCE model can reliably reproduce the behavior of a full engine with single-stage turbocharging, it played a critical role in determining the boundary conditions for both the 3D-CFD simulation and the simulations with the SCE model. The SCE model, on the other hand, includes all components relevant for the test bed and thus permits both a reliable design of the gas path and the development of a safety concept, which is of remarkable importance for high-pressure gas applications. With regard to the safety concept, this paper presents and discusses the difficulties in detecting injector malfunction and different detection strategies.