Turbocharging dramatically improves the power density of internal combustion engines both in the compression ignition and the spark ignition cases. However, a standalone turbocharger (T/C) suffers from transient and steady state downfalls where the energy to turbine is either smaller or larger than what would be needed to optimize the engine operation in a specific steady state or transient point. Hence a concept was proposed of a super-turbocharger where the T/C shaft is connected to the crankshaft through a continuously variable transmission and a gear. Energy is drawn from the crankshaft or delivered to the crankshaft to improve the work in every operating point of the steady map. In this paper, the concept of super-turbocharger is applied to a six-cylinder, dual fuel diesel injection ignition engine. The system is modelled using state-of-the-art automotive software and simulations of the steady-state operation are presented. This paper concentrates on the case of post injection of the LPG. Results of engine performance simulations are presented in detail.