Performance and In-Cylinder Pressure-Based Diagnosis of a Single-Cylinder Variable Compression Engine Developed for Education and Research

The object of this paper is to present the operability of a variable compression ratio engine developed to study the combustion characteristics of alternative fuels under different speed and load regimes when exploitation parameters are changed. The variable compression ratio engine is a modification of a commercial single-cylinder diesel engine with adjustable combustion chamber volume, fuel, and ignition systems, envisioned to operate in spark ignition or compression ignition mode. After explaining the experimental plan, designed to evaluate the engine performance comprehensively, a sample of the engine performance and thermodynamic results under spark ignition mode for a chosen condition of speed and load operation with three compression ratio values (9, 12, 14) and three gasoline-ethanol blends is detailed. Torque, power, fuel consumption, and in-cylinder-pressure-related indicated parameters for the experimental cases carried out, are compared. The results show the suitability of the developed engine to evaluate the influence that changes in fuel-mix composition, compression ratio, and tuning parameters have on the performance and combustion response of the engine.