Analysis of oil flow mechanisms in internal combustion engines via high speed Laser Induced Fluorescence (LIF) spectroscopy

• Main Author: Zanghi, Eric (Eric James)
• Other Authors: Tian Tian.
• Format: Others
• Language: English
• Published: Massachusetts Institute of Technology 2014
• Subjects: Mechanical Engineering.
• Online Access: http://hdl.handle.net/1721.1/92107

Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2014. === Cataloged from PDF version of thesis. === Includes bibliographical references (pages 86-88). === Automotive manufacturers have a significant challenge ahead of them with new more stringent regulations for exhaust emissions and fuel economy being implemented in the coming future. To make an impact on current emissions and fuel economy, new advanced analytical methods, such as high speed Laser Induced Fluorescence (LIF), must be employed when studying an internal combustion engine. With lubrication in the piston-ring pack assembly being one of the most significant contributors of oil consumption, it directly impacts exhaust emissions as well as indirectly affect fuel economy. High speed LIF spectroscopy has the ability to observe any oil flow mechanisms inside the cylinder which may be directly correlated to performance or oil consumption. This study intended to be a development process of taking a slower sampling LIF system and creating the high speed LIF for more advanced diagnostic purposes. Significant flaws were observed in the original LIF system, such as extremely low temporal resolution and error caused by temperature dependence in the dyes used for LIF spectroscopy. To develop this system, new lasers, optics, and cameras had to be tested to find which gave the best possible images. The implementation of the high speed camera fundamentally changed the observations and allowed for precise analysis of any and all oil flow mechanisms present in an internal combustion engine. While testing the system, old phenomena that had been previously documented allowed for a pseudo-calibration in which confirmation could be made that the system is working in a similar manner to the original system. Slow and fast cavitation effects were clearer than previous videos as well as the bridging effects which can be so detrimental to oil consumption. Even new phenomena were documented which provided much more work to be done in the future to truly understand and analyze these new oil mechanisms. This research is very much a diagnostic proof of concept such that others may be able to build such an analytical tool to understand oil flow mechanisms inside and internal combustion engine to better the fuel economy or exhaust emissions. Future experiments will truly determine the limit of what the system can do and how it can impact future engine designs. === by Eric Zanghi. === S.M.