The efficiency of internal combustion engines, exhaust aftertreatment systems, and electric propulsion systems exhibits high sensitivity to their respective operating temperatures. Therefore, optimal thermal conditioning of these systems enables efficient and low-emission operation, meeting the demand for sustainable individual mobility. This dissertation contributes to the integration of the propulsion system and the thermal management system into an energy management system of a diesel-hybrid vehicle. Integration requires a thermal management system that addresses the best possible thermal conditioning of the drive components and the exhaust gas aftertreatment system. The objective of this work is the conceptualization of a holistic thermal management system, consisting of a highly integrated thermal circuit system and an innovative diesel exhaust aftertreatment system. The highly integrated thermal circuit system allows for a situation-based transfer of heat flows between the propulsion systems for thermal conditioning by directly connecting the individual thermal circuits of the internal combustion engine, the electric motors and power distribution unit, and the battery. Simulations demonstrate the potential of coupling the thermal circuits and can be confirmed through cosimulation experiments on the system test bench "ThermoLab EVO 2". Particularly in critical operating conditions, the highly integrated thermal circuit concept offers advantages in terms of vehicle efficiency and ensuring compliance with thermal system limits. Within the framework of the thermal management system, it is also necessary to design the exhaust gas aftertreatment system to achieve high emission conversions immediately after an engine start to meet future global emission requirements. The challenging reduction of nitrogen oxides, especially in diesel engines, is addressed by positioning an SCR-system upstream of the turbocharger. The higher temperature level upstream of the turbocharger leads to faster light-off of the system compared to a conventional exhaust aftertreatment system after the turbocharger. The Pre-Turbo-SCRsystem features a bypass that allows for bypassing the Pre-Turbo-SCR in special operating modes and when the underfloor system is warm for operation. Measurements of the comprehensive Pre- and Post-Turbo-systems in dynamic test bench tests shows that with an adapted AdBlue® operating strategy, conversion rates of over 90 % are possible in cold start tests without performing CO2-intensive heating measures. Thus, the system addresses the trade-off between CO2 and zero-impact emissions.