A Fundamental Analysis for Steady-State Operation of Linear Internal Combustion Engine-Linear Generator Integrated System

Linear internal combustion engine-linear generator integrated system (LICELGIS) is an innovative energy conversion device with the ability of converting mechanical energy into electrical energy, which allows it to be a range extender for hybrid vehicles. This article presents a fundamental analysis for the steady-state operation of the LICELGIS, concentrating on electromagnetic force and motion characteristics. Simple assumptions are made to represent ideal gases instantaneous heat release and rejection. Based on assumptions, sensitivity analysis is carried out for key factors of electromagnetic force. The theoretical velocity model in mathematics is derived from analyzing the LICELGIS theory model. It shows that fuel injection quantity and stroke length are the most sensitive factors in key parameters. The piston velocity around the top dead center (TDC) changes greater than that at any other position, which is caused by the combustion process. The theoretical velocity model is sufficiently accurate in the second half-stroke (the maximum of relative error is within 2.78%). This velocity model is used to develop a relevant control strategy based on the piston velocity. Results are verified by a MATLAB/Simulink simulation model, which is validated by an experimental prototype. This fundamental analysis is useful for parameter selection and steady-state control of the LICELGIS.