The Use of Control Volume Analysis and Non-potential Junction Concepts to Model Liquid Piston Engine Dynamics

A study of the dynamics of a liquid piston engine/pump is undertaken using the bond graph modeling technique. Several of the highly transient hydraulic components used in liquid piston engines are studied with a control volume analysis and their bond graph representations are presented. These components form a set of "building blocks" which can then be joined together by "non-potential" hydraulic junctions to model complex liquid piston engine configurations. A total bond graph of a simple 2-stroke liquid piston engine is assembled using these components and results from a simulation study of the state equations derived from this bond graph are presented.