Dynamic and vibration modeling of internal combustion engines

Although new drive technologies, mainly electric power, are gaining ground and attracting R&D investment in the wake of the Paris climate agreement, the future of internal combustion engines still has room for technical progress and a commercial future in several industrial sectors, notably electricity generation. The inadequacy of charging and storage infrastructures, and the environmental impact of fuel cell recycling, remain major technical challenges if electric power is to be used in the mining industry, for example. Other emerging alternative energies, such as wind, solar and geothermal power, are limited by the intermittency and variability of the energy they produce. They can therefore only be used as a complement to another energy source. This diversification and complementarity of energies will have a major impact on tomorrow's industry, as well as on investment costs.

Resulting from the combustion of several cylinders in succession, the torque generated by an internal combustion engine is non-uniform during a 2-stroke or 4-stroke engine cycle. This natural acyclism is compounded by the dynamics of major components such as the crankshaft and engine block. This is what makes these engines vibrating machines. In the article [BM 2 610] , an appropriate choice of architecture parameters for V-type internal combustion engines to reduce their various types of vibration at source was detailed. As part of an approach to optimizing the ignition sequence, the aim of this dynamic control is to avoid premature aging of components and repeated failures. For some critical situations, and depending on the progress of the project, technical solutions have also been proposed. This second part of the work explains how multi-body modeling, based on modal synthesis, represents an ideal candidate for predicting the dynamics of internal combustion engines and their components. This covers all rotating and static parts of these engines, with an increasingly realistic representation of the various mechanical stresses. Current international standards will also be mentioned.

The essential aim of this article is not to present the state of the art in dynamic substructuring methods, but rather to introduce the reader to the principle of this approach and to introduce this methodology in a context of development and vibration assessment of internal combustion engines. This is the idea behind the first section, which reviews the basic concepts of modal synthesis....