0D AND 3D SIMULATION STUDY OF THE PERFORMANCE CHARACTERISTICS OF A 5-STROKE ENGINE

Author

• Kurt Duane Stuart, Southern Illinois University CarbondaleFollow

Date of Award

8-1-2026

Degree Name

Doctor of Philosophy

Department

Engineering Science

First Advisor

Mathias, James

Second Advisor

Shavezipur, Kamran

Abstract

The 5-stroke engine is a novel high efficiency engine cycle that combines a traditional 4-stroke engine with a dedicated cylinder which further expands the combustion gases to recover additional work from the exhaust stream. This work investigates the performance of the 5-stroke engine, using a 0D Air Standard model, 0D 2-zone equilibrium combustion products model, and 3D turbulent combustion CFD models. Compared to prior published work, this study explores the differences in the results of different simulation models while also identifying significant performance limiting parameters. Results are reported as indicated thermal efficiency over a range of design characteristics, including overall expansion ratio, clearance volumes, and valve timing events. Pressure-volume relationships, work output, mass and heat transfer are also examined to investigate simulation model performance and areas for improvement. The results demonstrate that the low-pressure cylinder clearance volume ratio, and the pumping work during the exhaust stroke have significant effects on the engine’s performance. Pumping losses are found to increase with the overall expansion ratio therefore limiting the usable overall expansion ratio and achievable efficiency. Additionally, incremental increases in exhaust valve lift-area do not significantly reduce exhaust pumping work, suggesting that a more radical approach is required. 3D CFD provides improved simulation accuracy over prior 0D models, which are unable to accurately capture the gas flow processes.