A multi-physics multi-scale approach in engine design analysis

Vibration behaviour of an internal combustion engine depends on rigid body inertial dynamics, structural modal characteristics of its elastic members, tribological behaviour of load-bearing contacts, and piston-cylinder interactions. Therefore, it is essential to use a multi-physics approach that addresses all these physical properties in a single integrative model as presented in this paper. This approach can be regarded as holistic and a good aid for detailed design. Particular attention is paid to the critical elements in the system, such as load-bearing conjunctions (crankshaft main bearings) and piston-cylinder wall interactions. Another important feature is the integrated analysis across the physics of motion from microscale fluid film formation to submillimetre structural deformations and onto large displacements of inertial members. In order to succeed in predictions within sensible industrial time scales, analytical methods have been used as far as possible rather than numerical approaches. Model predictions show good agreement with fired engine test data.