Simulación de la inyección directa de combustible en motores de combustión interna

Abstract

Internal combustion engines have an essential influence in the global energy matrix since they represent more than half of the global consumption of fossil fuels. In this context, research efforts for new technologies must be done in order to improve engine efficiency and reduce pollutant emissions. In view of this, this thesis present simulation techniques for internal combustion engines which are conceived to perform whole-cycle simulations in reduced computational times. The models are designed to work with parallel computational architectures aiming to achieve high scalability and computational performance. In detail, several dynamic mesh techniques are studied focusing on non-conformal interfaces and topological mesh changes. These new developments are conceived to handle the interaction between the engine moving parts and to manage the great domain deformations of the cylinder region. In concordance with the features of the dynamic mesh techniques, a Lagrangian strategy for particle tracking is designed to simulate the liquid phase regarding fuel injection. For the liquid atomization, a hybrid model is implemented and a sensitivity study of its parameters is performed to validate the model with experimental data. The new developments are applied over an opposite piston engine which is being developed in the region. The stability and computational performance of the new numerical methods are evaluated studying the numerical influence of some injection parameters on the opposite piston engine performance.