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The reduction of environmentally harmful gases and the ambitions to reduce the exploitation of fossil resources lead to stricter legislation for all mobile sources. Legislative development significantly affected improvements in emissions and fuel consumptions over the last years, mainly measured under laboratory conditions. But real world operating scenarios have a major influence on emissions and it is already well known that these values considerably differ from officially published figures [1]. There are regulated emissions by the European Commission by means of real driving scenarios for passenger cars. A methodology to measure real drive emissions RDE is therefore well approved for automotive applications but was not adapted for two-wheeler-applications yet [2]. Hence measurements have been performed on-road and on chassis dynamometer for motorcycles with the state of the art RDE measurement equipment to be prepared for possible future legislation.

Real world operating scenarios have a major influence on emissions and fuel consumption. To reduce climate-relevant and environmentally harmful gaseous emissions and the exploitation of fossil resources, deep understanding concerning the real drive behavior of mobile sources is needed because emissions and fuel consumption of e.g. passenger cars, operated in real world conditions, considerably differ from the officially published values which are valid for specific test cycles only [1]. Due to legislative regulations by the European Commission a methodology to measure real drive emissions RDE is well approved for heavy duty vehicles and automotive applications but may not be adapted similar to two-wheeler-applications. This is due to several issues when using the state of the art portable emission measurement system PEMS that will be discussed.

The introduction of more stringent standards for engine emissions requires continuous improvement of exhaust gas aftertreatment systems. Modern systems require a combined design and application of different aftertreatment devices. Computer simulation helps to investigate the complexity of different system layouts. This study presents an overall aftertreatment modeling framework comprising dedicated models for pipes, oxidation catalysts, wall flow particulate filters and selective catalytic converters. The model equations of all components are discussed. The individual behavior of all components is compared to experimental data. With these well calibrated models a simulation study on a DOC-DPF-SCR exhaust system is performed. The impact of pipe wall insulation on the overall NOx conversion performance is investigated during four different engine operating conditions taken from a heavy-duty drive cycle.

The introduction of more stringent standards for engine emissions requires a steady development of exhaust gas aftertreatment in addition to an optimized cylinder combustion. The reduction of the cold start phase can help significantly to lower cycle emissions. With the goal of optimizing the overall emission performance this study presents a comprehensive simulation approach. A well established 1D gas dynamics and engine simulation model is extended by three key features. These are models for combustion and pollutant production in the cylinder, models for the pollutant conversion in a catalyst, and a general species transport model. This allows to consider an arbitrary number of chemical species and reactions in the entire system.

Future emission limits of diesel engines require additional effort for developing adequate and advanced exhaust gas aftertreatment devices. Urea-SCR systems are a promising approach to reduce nitric oxide emissions. Computer models as a complementary tool to experimental investigations help to make design decisions and to shorten the development process. Therefore, this work presents a comprehensive SCR simulation approach. All relevant conversion reactions are studied in a 1d model. The obtained parameters are transferred to 3d simulations and combined with a detailed description of the urea injection. Validation simulations are performed for the individual SCR reactions and show good agreement with experimental data. 1d studies of different SCR assemblies and sizes are presented. Full 3d simulations of an HSO system considering injection, homogeneous gas phase and catalytic reaction show the interaction of all relevant effects and their impact on the overall deNOx performance.

In this paper a reduced kinetic scheme adapted and optimized for HCCI applications is presented. This kinetic scheme uses three reactions for the low temperature oxidation and two reactions for the high temperature oxidation. In this work, the 5-step kinetic scheme is optimized using a genetic algorithm for two different sets of HCCI conditions: a near stoichiometric combustion with a high amount of exhaust gas recirculation and a lean combustion with no exhaust gas recirculation. The merit function used to perform the optimization is based on the comparison of the ignition delay calculated with the reduced scheme and a detailed kinetic scheme of reference. In this study, twelve parameters of the 5-step kinetic scheme are optimized for the two sets of HCCI conditions chosen. Finally, the reduced kinetic scheme is implemented in the 3D code FIREV8 and a fairly good agreement is obtained with experimental HCCI results.

In the near future the effort on the development of exhaust gas treatment systems must be increased to meet the stringent emission requirements. If the relevant physical and chemical models are available, the numerical simulation is an important tool for the design of these systems. This work presents a CFD model that allows to cover the full range of applications in this area. After a detailed presentation of the theoretical background and the modeling strategies results for the simulation of a close-coupled catalyst are shown. The presented model is also applied to the oxidation of nitrogen oxides, to a diesel particle filter and a fuel-cell reformer catalyst.