Development of a methodology for dynamic simulation of a variable valve actuation system

Nowadays car manufacturers must face the continuously tightening of greenhouse gases and pollutants emission regulations. Global warming threatens humans and planet health, forcing engine development for new technologies and solutions to be as fast as possible in order to comply with governments requirements on emissions. Therefore, CAE (Computer Aided Engineering) is becoming a very important resource in automotive industry. The possibility to reproduce systems behaviour with ever-growing reliability software enhances testing of new strategies while saving costs and time. Goal of the work was to define a new and innovative methodology to perform a dynamic simulation of a variable valve actuation system. A virtual model of a dual lift shifting system, capable of reproducing real behaviour of the existing component was expected to be the output of the present master thesis. The multi-body simulation was performed using the software \GT\ by Gamma Technologies LLC. which, thanks to its variety of tools covering many areas of virtual modelling, has been evaluated as optimum solution for results accuracy and computational time. Before going in detail with model building, a recall of engine fundamentals will be presented as well as an overview about the current situation in terms of variable valve actuation systems technologies being available on the market. A description of system's main components has been given subsequently. In this way, model building chapter of the thesis, concerning modelling strategies and limits of the simulation, can be explained more accurately. Comparison with experimental results has been performed to validate the work in terms of assumptions, simplifications and modelling strategies. Modelling parameters have been described and important results shown and analysed. Once the model has been built and evaluated an optimization process was presented, in order to show model capabilities and potential for system improvements. Finally, in the conclusions, results have been summarized and future developments proposed.