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Liebherr Machines Bulle SA has chosen a technical solution for their 4 cylinder engines on the basis of cooled EGR and a closed DPF system including a fuel dosing unit to achieve Stage IIIB / Tier4i Emission Standards. Main portions of the development, especially the engine and after treatment calibration was performed together with Engineering Center Steyr. The calibration was done under consideration of best fuel consumption, optimized combustion acoustics, satisfying vehicle dynamics as well as fulfillment of legislative regulations, engine and vehicle boundaries. The usage of complex software functionality, a sophisticated calibration process as well as a high end 2000bar injection system was mandatory.

A comprehensive simulation method is presented for the optimization of vehicle warm-up. Sophisticated one dimensional simulation methods based on network theory are used for flow simulation to limit computation time and guarantee high simulation quality. Partial integration of three dimensional flow simulation methods help to improve accuracy. Simulation sub-models for the engine, the HVAC system, and the passenger cabin are combined to simulate the warm-up process of the vehicle. This functionality is implemented in a modern software tool named KULI to support the development engineer as good as possible. Steady state and transient simulation are used to optimize the warm-up behavior.

An efficient air-conditioning system is an important factor for the commercial success of an automotive product, because of the thermal comfort for the passengers being an important incentive for the purchaser. A simulation tool is presented that makes it possible to design and optimize A/C refrigerant circuits together with the engine cooling system in a very early stage of the design process. This tool is based on networks including the enhanced heat exchange theory which also takes into consideration refrigerant phase changes. A graphical user interface and predefined simulation models which are based on the respective geometry of the system components make it easy to create a virtual vehicle for mathematical analysis of the various heat and mass flows. High flexibility and short calculation time together with high accuracy enable the engineer to make efficient investigations.