Research And Application Of Eigenvector-based Methodology For Characterizing The In-cylinder Air Motion

Energy consumption and environment pollution are the main problems for automotive industry. Thus, the improvement of the fuel economy and low emissions are the main objectives of the vehicle engines. Numerous advanced technologies are developed during these years to meet the emission regulation and consumer’s demands because they mostly have great industrial potential. However, the designing of the inlet port of the engine and optimizing the air flow inside the cylinder is a fundamental requirement for the development of the new combustion system or the performance improvement of the engine, so detailed knowledge of producing, optimizing, measuring and characterizing of the air flow inside the cylinder is indispensable for the vehicle engines.The new methodology for characterizing the inside the cylinder of the engine is mainly focused on in this research. The novel double eigenangle-based steady flow test rig has been developed, and the compositions, principle, working style and experimental process are expatiated and the data acquisition system is built up, too. Based on the double eigenangle-based steady-state flow test rig, the main work of this research is shown as follows:The new methodology for characterizing air flow inside the cylinder is established, and the concept of eigenvector, the eigenvector path of the in-cylinder air flow, the eigenvector table under different valve lifts are introduced in this paper to get a macroscopically reflection of the intensity, the tested plane, the vector direction and the distribution of the inclined swirl;A 4-valve PFI gasoline engine cylinder head was investigated comprehensively based on this novel test rig. The simulated and tested data were compared, and the accuracy, reliability and applicability of the new methodology mentioned above are validated;Based on the inlet port optimization of the PFI gasoline engine, a LPDI gasoline engine using air-assisted technology and spray guided direct injection combustion system was developed. The simulation model of the inlet ports was built up, and the simulated results were compared between PFI and LPDI engine on in-cylinder air flow. The novel double eigenangle-based steady-state flow test rig was used, and the concept of eigenvector, the eigenvector path of the in-cylinder tumble flow, the eigenvectors under different valve lifts were built to comprehensively investigate and contrast in-cylinder air flow of the two engines; besides, the results of the optimizing inlet port is analyzed and expatiated.