One of the main objectives of HugYourEngine is to shine a spotlight on individuals who are helping make internal combustion engines cleaner and more efficient. This spotlight is on Dr. Flavio Chuahy.
Flavio Dal Forno Chuahy is a Post-doctoral Research Associate in the Fuels and Engines Research Group at Oak Ridge National Laboratory (ORNL). He received his doctoral and master’s degrees in Mechanical Engineering from the University of Wisconsin – Madison’s Engine Research Center, and his bachelor’s degree in Mechanical Engineering from the Maua School of Engineering in Sao Paulo, Brazil. His research interests lie in exploring novel electrochemical-combustion systems for distributed generation, the study of fundamental fuel chemical class effects on cold-start and knock, as well as the effects of turbulence-chemistry interactions, thermo-diffusive effects and flame topology in dilution tolerance of high efficiency spark ignition engines. Dr. Chuahy has almost 10 years of experience in engine testing and development having worked at Cummins as a calibration engineer (2010-2012) and heavy-duty engine optimization lead (2018), and at Electro Motive Diesel as a CFD analyst for engine support systems (2012-2014).
Kelly Senecal (KS): When and why did you get started in combustion research?
Flavio Chuahy (FC): I can’t say I worked on combustion research per se before joining graduate school. However, I have been working with engine testing and engine development since 2009 when I started an internship at Navistar in the engine calibration group. This was my first contact with engine testing and calibration and set me up for a long career in the field of combustion. There I first encountered in-cylinder analysis, combustion emissions control, and aftertreatment. Since then I’ve tried to move towards more and more fundamental research. Towards that goal, after a few years in the industry, I decided to apply to graduate school. The Engine Research Center at Wisconsin seemed like the obvious choice to me after reading about the many contributions the lab had made to engine research under the guidance of Prof. Rolf Reitz.
KS: What are you working on now?
FC: I am currently working on a number of experimental and computational projects at ORNL. My experimental work is focused on two topics, (1) studying fuel chemical class composition effects in order to understand the trade-offs between advanced compression ignition modes and spark ignition (SI) operation on multi-mode engines, and (2) characterizing combustion and emissions during cold-start of SI engines by employing conventional and advanced diagnostic techniques. On the computational side I am supporting an experimental project on high efficiency stoichiometric SI engines through detailed CFD simulations.
KS: Describe your lab facilities.
FC: ORNL’s transportation research features an extensive array of engine test cells dedicated to combustion and emissions research, which include, but are not limited to single- and multi-cylinder engines as well as conventional and hybrid powertrain/engine testing. I am mainly involved in one of our single-cylinder engines which represents modern direct-injection SI designs. Our engine is modified to allow operation under spark ignition and advanced compression ignition strategies, with and without exhaust gas recirculation in addition to full cam position autonomy. The cell is capable of delivering both liquid and gaseous fuels over a range of fuel pressures. Emission characterization is accomplished through gaseous bench measurements as well as FTIRs and particulate matter emissions can be characterized both in composition and size distribution through a variety of equipment and techniques.
KS: What’s your favorite type of flame?
FC: My favorite kind of flames are thermonuclear flames. It is theorized that these flames exist in the explosion of a certain type of white dwarf star into Type Ia Supernovae. It is fascinating to me that the complex small-scale dynamics of turbulent flames that vex researchers in the field of engines are also essential to understanding complex cosmological phenomena like Supernovae. Not only that, understanding these events in a more fundamental way could have a significant impact towards our understanding of the universe, which is just awesome. I hope one day I get to work on this topic.
KS: What’s your favorite fuel?
FC: My favorite types of fuel are definitely ethers. From a performance standpoint they offer a sea of untapped potential for low sooting and highly efficient diffusion combustion. From a carbon intensity perspective, they are part of the gamut of possible e-fuels which can eventually lead to carbon neutral fuel synthesis and consumption. There are still many application challenges that have to be sorted before ethers can even be considered for the mass market.
KS: What advice would you give students thinking about going into combustion research?
FC: Go for it. Combustion is a pervasive topic that doesn’t just apply to internal combustion engines. It is a complex field that can be extremely fundamental in nature, such as in direct numerical simulations, or very applied like the work we do in metal engines. It is extremely exciting, challenging, and the research has far reaching impact. We need extremely motivated individuals to join the fold and help propel the field in new innovative directions.
KS: Is the IC Engine dead?
FC: The IC engine is not dead due to a variety of reasons. However, I think perhaps the most compelling might be the sheer scale of the transportation sector. In the US alone the transportation sector is responsible for approximately 23% of all CO2 emitted and ~140 billion gallons of fuel consumed each year. A staggering amount. Within those numbers we have several different applications with specific duty cycles and market requirements that might be conducive to electrification or not. Electrifying such a fleet in 10-20 years seems an insurmountable task and will have far reaching implications to grid stability and infrastructure. We tend to also forget that there are another 194 countries that may not be as developed as the US and have varying levels of grid CO2 intensity. If we want to have global impact we need to further improve the IC engine and democratize that technology.
KS: How is your work helping improve fuel efficiency or reduce emissions?
FC: Understanding the impact of fuel chemical functions on advanced compression ignition will help guide the development of new fuels that are capable of extracting the best of different combustion modes. Our work on cold-start will help address one of the most important sources of emissions in light duty vehicle cycles and allow for higher efficiency during that critical part of the engine operation. My work in combustion CFD is geared towards more fundamentally understanding dilution tolerance and cycle-to-cycle variability seen in experiments in order to push the boundary of what’s possible in stoichiometric SI engines. The goal is to achieve “diesel-like” efficiencies by only improving conventional SI combustion, thus facilitating adoption.