Doctoral Finishing Fellowship Summer 2021 Recipient – Oudumbar Rajput

I obtained my Bachelor of Engineering degree in Mechanical Engineering from University of Pune in 2013.I started my graduate studies at Michigan Technological University in Fall 2015. During my master’s degree program, I joined Dr. Youngchul Ra’s research lab (Reacting Flows and Fuel Research Lab) at Mechanical Engineering-Engineering Mechanics department and started my Ph.D. program in January 2017. The focal point of my research is to use in-house computational fluid dynamics tool to numerically develop a novel six-stroke gasoline compression ignition (6S-GCI) engine cycle to improve fuel consumption, reduce emissions, extend the operating range of conventional four-stroke GCI, and stabilize the engine operation at low loads.

A high compression ratio engine with two intake/exhaust valves is used for this work. The first task completed focused on understanding the impact of valve opening/closing timings on the overall combustion behavior in 6S-GCI engine. It successfully demonstrated that the 6S-GCI cycle improves fuel consumption compared to corresponding four-stroke operation. An important finding is that both kinetically-controlled mode (KCM) and mixing-controlled mode (MCM) of combustion could be achieved in the second power stroke maintaining low soot levels. Next, attention was paid to understand the underlying physics of combustion regime change (KCM/MCM). To achieve this, the impact of the variation of split ratio (ratio in which total fuel was divided amongst both the power stokes), fuel injection timings, intake temperature, boost pressure, EGR ratio, and injection pressure on overall combustion and emissions performance was analyzed. Finally, the effects of injector configuration and piston bowl geometry characteristics on fuel oxidation rates and formation and oxidation rates of emissions were analyzed. The work completed thus far helps not only to gain an understanding of the mechanism of enhancement of combustion phasing controllability, stabilizing of engine operation at low engine loads, and improvement of combustion efficiency, but also in planning new experiments, and in designing new engines.

I would like to sincerely thank the Graduate Dean Awards Advisory Panel for providing me with the Finishing Fellowship award. This will allow me to focus on defending my dissertation in summer 2021.