Simulation of full and part-load performance of a free-piston gas generator by electronic analog methods

Abstract

In this investigation, use was made of an electronic analog for simulation the operation of a free-piston gas generator. The basic concept of the analog was developed in a previous investigation and involved creating of the various free-piston forces as functions of displacement and integrating these combined forces in accordance with Newton's second law of motion to obtain a solution representing piston motion - all by electronic analog means. Modifications were made to the basic analog circuit of the previous investigation to overcome an unstable operating condition. The modified circuit was then employed for determining performance characteristics of an actual free-piston gas generator under varied load conditions. The results of these studies showed that the operation of a free-piston gas generator could be simulated to a reasonable degree of accuracy and stability by use of an electronic analog and that this method might be a valuable means for design and performance predictions of free-piston engine systems.