Description of a Novel Concentric Rotary Engine

The present work presents the concept of a new rotary engine, and provides first investigations for its implementation in the energy sector. The main focus of this work is to provide a theoretical description of the engine and its differences from the state-of-the-art technologies. Its innovative principle consists of concentric operation, with two pistons of different rotation radius and the addition of a third intermediate chamber between the compression and combustion chamber. A description of the engine’s physical model is provided, followed by an analysis of the selected specific geometrical features. Additionally, a thermodynamic analysis clarifies the operational advantage compared to the existing cycles and, finally, a numerical investigation on the engine’s bulk performance is provided to quantify the anticipated results of the theoretical analysis. The theoretical description concludes that the new rotary engine is characterized by simple design with the minimum possible moving parts that can be easily integrated into hybrid systems or small sized applications. Its anticipated volume and weight is five to six times smaller than that of conventional engines owing to the fact that there is no need for motion conversion system and there is one power stroke in every 180 degrees. Last but not least, its expected thermal efficiency based on Atkinson cycle can theoretically be 15% greater than that of existing engines for the same application.