DEUTZ has developed a diverse portfolio of drive technologies for mobile machines, in which the combustion engine continues to be an important factor. This also results from load profiles for which electric drives or fuel cells are not an economically viable alternative. For this reason, DEUTZ has developed a new TCD3.9 and TCD4.0 engine series, primarily for use in mobile machines, but also for other non-road applications, which replaces the established TCD3.6 and TCD4.1 engines. Care was taken to ensure that the TCD3.9/4.0 is compatible with the installation of the TCD3.6. Due to the increased displacement, increased peak pressure, high turbocharger efficiency and the elimination of exhaust gas recirculation, the output can be increased to 130 kW and thus exceeds the values of the predecessor TCD4.1, which has a larger displacement. Both engine dynamics and fuel consumption can be improved. After the engine was presented at the ATZ Congress in Eisenach with a focus on its design features, this paper will focus on thermodynamics and emission behavior. This concept not only serves the highly regulated EU Stage V and US EPA/CARB Tier 4 emission markets with a very powerful SCR system that avoids the use of exhaust gas recirculation, but also includes a variant for those markets where ECE R49 Stage III A certification is sufficient, which requires exhaust gas recirculation but no exhaust gas aftertreatment. Due to the modular design, the engine has the potential to comply with future emission standards such as the announced CARB Tier 5.