Computational studies of homogeneous charge compression ignition, spark ignition and opposed piston single cylinder engines

In this research, possible improvements in engine specifications using the simulations developed on the AVL BOOST™ and Ricardo WAVE™ platforms were investigated. These modelling simulations help the author to predict the effect of any improvements in engine specifications without practical experimental challenges and difficulties. Firstly, HCCI and SI engines were modelled with the intention of maximizing the engine’s efficiency and minimizing the emissions. Changes of valve timing and throttle angle influence emissions’ reduction and the efficiency of the engine. In SI engines, the emissions of NOx can be reduced by using EGR, while only having a little effect on performance. The emissions from the HCCI, due to their intrinsically low emission output, were not improved. The effect of increasing the bore to stroke ratio in an opposed piston engine whilst maintaining a constant swept volume, port geometry and combustion timing, shows an increase of heat losses due to the lower ratio of exposed surface area to volume; an increase in thermal and mechanical efficiency; and most importantly, an improvement in fuel consumption. Also, in this research study, different strategies for opposed piston engines were investigated to increase the engine’s efficiency. The effect of a variable compression ratio on an opposed piston engine’s performance indicates different behaviour at various engine speeds and under different running conditions.