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Title: Advancing Science for Automotive Innovation: Optical/Laser-based Imaging Diagnostics in Gasoline and Diesel Engines

Time: 10:00 to 12:00, Oct. 22, 2018

Place: F103, School of Mechanical Engineering

Host: LI Xuesong, Associate Professor (Institute of Automotive Engineering)
 

Short Bio:

Associate Prof Kook directs the UNSW Engine Research Laboratory with research grants worth more than $12 Mil since 2009. His expertise lies in optical/laser-based imaging diagnostics in challenging engine environments, advanced combustion strategies and alternative fuels in gasoline/diesel engines as well as soot morphology. Before joining UNSW in 2009, he received research training at Sandia National Laboratories (Postdoc in 2007-09) and KAIST (BS in 2000, MS in 2002, and PhD in 2006). He has authored more than 160 journal/conference papers including a paper received the 2005 SAE Horning Memorial “Best Paper” Award and the SAE Outstanding Oral Presentation Award twice in 2016 and 2018.
 

Abstract:

This talk presents various images and movies obtained from optical/laser-based imaging diagnostics performed in optically accessible gasoline and diesel engines. The fundamental understanding is enhanced by directly visualising flow, air/fuel mixtures, reaction and pollutants, and interpreting their physical meanings. There are three main topics covered in this presentation including 1) flow fields in a spark-ignition direction-injection (SIDI) gasoline engine, 2) in-flame soot particles in an SIDI petrol engine and a diesel compression-ignition (CI) engine, and 3) ignition process in a gasoline CI (GCI) engine. The flow field imaging is based on time-resolved, cinema particle image velocimetry (PIV) conducted in an optical SIDI engine. The main emphasis is on injection timing variation as both the flow velocity magnitude and flow fluctuations are significantly impacted. Regarding the soot particles, thermophoresis-based in-flame particles sampling and subsequent transmission electron microscope (TEM) analysis is performed in the same optical SIDI engine. Using the sampling probes installed on the piston top, the soot particles are directly sampled from the gasoline flame for detailed analysis of particle size distribution, structure and shape. A similar sampling experiment is also conducted in an optical diesel engine by installing the sampling probes within the piston bowl so that diesel soot particles are directly sampled from the flames. Together with planar laser-induced incandescence (PLII) and planar laser-induced images of OH (OH-PLIF), in-cylinder soot formation and oxidation processes are clarified. The last part of this presentation covers partially premixed charge-based gasoline compression ignition (GCI) combustion, which achieves very high engine efficiency and low NOx and soot emissions. Through the natural combustion luminosity and electronically excited hydroxyl (OH*) imaging conducted in the same optical CI engine as the diesel soot experiment, the ignition kernel development and flame growth rate analysis is performed. These findings are intended to accelerate the development of enabling, implementation-ready technologies addressing ever-increasing demands in the automotive market of today and foreseeable future.