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A combined finite element method (FEM), multibody system simulation (MSS), and hydrodynamic (HD) bearing simulation technique can be applied to solve for engine crankshaft and cylinder block dynamics. The cylinder block and crankshaft are implemented in the MSS program as flexible FEM structures. The main bearing oil film reaction is described in the MSS program by a pre-calculated reaction force database. The results are displacements and deformations of the crank train parts and the main bearing reaction forces. Verification of the tool was carried out by comparison of main bearing cap accelerations to measured data.

Within the PNGV program, very challenging targets in respect to vehicle fuel economy were set. These could not be met with today's gasoline engines and driveline concepts. One possible alternative approach is a hybrid vehicle with a small displacement engine that exceeds the fuel economy of conventional engines: the 1.2L DIATA (Direct-Injection-Aluminum-Throughbolt-Assembly) engine. Within the development of a CIDI engine the NVH aspects are of particular importance as the customer (i.e., driver) should not notice any negative difference to gasoline engines. Therefore, gasoline engine transparency in respect to NVH was one primary goal within the development process. This paper describes the implementation of NVH features into the engine design already in the initial concept design phases, and the consequent NVH optimization throughout the development phase.