Ph.D. Defense | Vijai Shankar Bhavani Shankar



Double Compression Expansion Engine: Evaluation of Thermodynamic Cycle and Combustion Concepts


Vijai Shankar Bhavani Shankar, Ph.D. Candidate Supervised by Prof. Hong G. Im


Thursday, November 07, 2019


02:00 PM - 03:00 PM


Building 5, Room 5220


The invention of mechanisms to convert chemical energy into mechanical work has paved the way for modernity. The piston reciprocating internal combustion (IC) engine is unique among these inventions since it led to the democratization of mobility, which has brought wealth, health, and prosperity to the masses. IC engine has a relatively simple architecture and constituted by ubiquitous materials. Its design offers robust operation and easy maintenance at a reasonable cost. Finally, it is powered by an abundant energy source. IC engines are poised to continue their role as the primary mover of people and goods in the 21st century.

The gradual electrification of vehicle powertrains adds a new degree of freedom for the development of IC engine technology. The optimization of the thermodynamic cycle of IC engines, however, remains the primary avenue for improving the efficiency of the engine. This thesis presents a detailed study of an engine concept that is designed to accomplish an over-expanded thermodynamic cycle that increases the thermodynamic efficiency while maintaining high efficiencies for other engine processes leading to better utilization of fuel energy. This engine concept is called the Double Compression Expansion Engine (DCEE). The efficiency potential, energy flows, and unique attributes of the DCEE concept were explored using 1-Dimensional engine modelling.

The DCEE concept was contrasted against a conventional engine architecture through extensive simulation study. The DCEE concept exhibited a significant improvement in the engine efficiency, while providing increased degrees of freedom to tailor the heat addition process. The sensitivity of the DCEE concept to several design and modelling parameters was rigorously explored to identify pathways for enhancing its efficiency. Finally, the synergies of adopting low-temperature combustion (LTC) concepts in the DCEE was investigated.


Vijai Shankar is a Ph.D. student in the Clean Combustion Research Center. Vijai received his B. Tech in Automotive Engineering from SRM University in India, and his M.Sc. in Aerodynamics and Aerostructures form the University of Sheffield in United Kingdom. He has published 14 peer-reviewed papers in the field of combustion engines and fuels. 

Event Quick Information

07 Nov, 2019
14:00 PM – 15:00 PM