Understanding oil transport mechanisms is critical to developing better tools for oil consumption and piston skirt lubrication [1]. Our existing Two-Dimensional Laser Induced Fluorescence (2DLIF) system with an acquisition rate of 1 frame every one or two cycles was proven to be effective to display oil accumulation patterns and their evolution over many cycles in the piston ring pack system [2,3,4]. Yet, the existing system is unable to resolve instantaneous oil flow patterns in the piston-liner interface.
In this work, a high-speed LIF system was developed. After a number of iterations the finalized high speed LIF system includes a 23 W, 100 kHz, 532 nm laser and a high speed camera capable of 100,000 FPS at 384 × 264 pixel resolution. After each component was selected, optimization of the quality of images taken from the system began. Each component in the optical system was tested for improvement of image quality; such components include: camera lens, beam expander, beam splitter, and optical filter.
A few examples will be shown demonstrating the effectiveness of the system at visualizing oil flow mechanisms inside an IC engine. The first demonstrates the importance of understanding oil flow in the skirt region of the piston while the second focuses on the behavior of oil flow through the ring pack; specifically the Oil Control Ring (OCR) gap. Lubrication phenomena such as separation, cavitation, shearing, etc. can be seen using the high speed LIF system allowing for correlations between piston/ring pack design and oil behavior to be derived. Quantitative results are not currently possible with the current system, but will be researched in the near future. Videos produced by the high speed LIF system are also used to further the development of piston and ring pack lubrication models [5].