[Abstract nur auf Englisch verfügbar.] The title of this thesis is "the optimum operation of hybrid vehicles". The objective was the development of new methods for the optimal control of hybrid drives and the modelling of the driveline including the combustion engine's emission behaviour. The methods were used to analyze and to optimize the TUM's Autark Hybrid Vehicle. The optimum values of fuel consumption and the resulting exhaust emissions were determined as well as the optimum rating of components. In a first step, the research about the so called "offline optimization method" was continued to obtain fundamental results by simulation. This method uses optimal control theory to calculate the hybrid powertrain's control trajectory for a given driving cycle. The objective was the minimum possible fuel consumption, with the boundary condition of an equalized state of charge of the traction battery over the driving cycle. In a second step, a new optimization method for the realtime control of hybrid vehicles was developed, which can be implemented into the vehicle's controller system. This "online optimization" bases on the minimization of the powertrain's power losses in each discretisized point of time. The bilance of power losses is modified by the internal power of the traction battery to solve the problem of the torque split between combustion engine and electric motor correctly. Besides fuel consumption, the emission behaviour as the second important aspect has to be considered. The objective was a direct comparison between the engine operation at a conventional passenger car and the optimized engine operation in the hybrid vehicle. The TD engine, which is actually implemented in the Autark Hybrid's driveline, could be investigated by measurement at the teststand. In addition, the emission behaviour of a modern TDI engine was studied by simulation. Therefore, the modelling of the combustion engine's thermal behaviour was necessary as well as the development of a model for the heat transfer and the reaction kinetics in the catalysts. If the Autark Hybrid Vehicle is compared to a conventional car with the same combustion engine, the fuel saving potential in the NEDC would reach a level of 15% for both the TD and the TDI. In the ECE-Citycycle part of the NEDC, up to 30% are possible. The optimum rating of the electric drive needs an upper power limit of 12 to 16kW. If overload operation is possible, the rated power can be set to a smaller value, e.g. an 8kW-engine can be used. The emission values of CO and HC are significantly reduced at the Hybrid, and the temperature level in the catalyts reaches normal values. The NOx-production of the TDI engine may be a problem, because it increases significantly at hybrid operation and needs an aftertreatment by an additional SCR-catalyst.
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