COMBUSTION ENGINES, No. 2/2015 (161) Ali ALQAHTANI Farzad SHOKROLLAHIHASSANBAROUGH Miroslaw L WYSZYNSKI Thermodynamic simulation comparison of AVL BOOST and Ricardo WAVE for HCCI and SI engines optimisation The aim of this paper is to compare two simulation software platforms, AvL BOOST™ and Ricardo WAvE™ as used to simulate HCCI and SI GDI engines with the intention of maximising the engine’s efficiency and minimising the emissions. This paper compares these platforms in an experimentally validated model to analyse a spark ignition and a Homogeneous Compression Ignition Charge (HCCI) single cylinder 4 valve gasoline engines with multiple configurations and running parameters in order to find the most optimal setup for the engine, with the prospect of allowing an optimum engine to be built and tested in real world conditions without the need for multiple expensive prototypes and long delays. Key words HCCI, SI, numerical simulation, software platforms, AvL BOOST, Ricardo WAvE PTNSS-2015-208 Article citation info ALQAHTANI A, SHOKROLLAHIHASSANBAROUGH F, WYSZYNSKI ML. Thermodynamic simulation comparison of AVL BOOST and Ricardo WAVE for HCCI and SI engines optimisation. Combustion Engines. 2015, 161(2), 68-72. ISSN 2300-9896. 1. Introduction Modern software allows for accurate prediction of engine performance without the need to build a physical model. One-dimensional engine and gas dynamics simulation software packages such as Ricardo WAVE or AVL BOOST are relatively inexpensive tools for the engineering and design of modern engines. Using these programs changes the system of engine development resulting in a process that is far less reliant on building costly prototype engines and allows for various design parameters to be explored and optimised before any prototyping begins, vastly reducing research and development costs for new engine technologies. This paper investigates the use of modelling software platforms Ricardo WAVE and AVL BOOST to generate a model of a cylinder engine operating under various conditions and to determine the accuracy of the software by comparison with experimental results. The software can then be used to predict improvements that can be made to the model, and reduce the emissions of the engine.