Investigation of friction properties in the piston-cylinder liner region of a single-cylinder compressed air engine using the GT-SUITE program

Abstract

Dependence on nonrenewable fuels continues to a great extent today. Overuse of fossil fuels has brought along various environmental problems. In order to reduce such problems, compressed air engines have developed significantly during the last 20 years. Compressed air engines are environment-friendly engines that do not use fossil fuel and achieve expansion using compressed air. It is of great importance for engine efficiency to decrease friction losses of piston engines. There are not many studies in the literature focusing on friction manner of piston ring liner parts of compressed air engines with a piston. In this article, the transformation of a four-stroke gasoline engine with 388 cm3 displacement into a compressed air engine has been carried out and the friction manner between piston cylinder liner has been modeled with the help of GT-SUITE program using in-cylinder pressure-cylinder volume (P-V) data obtained from different engine loads under operating pressure of 12 bar and geometrical size of the engine. It has been determined according to the results of the simulation that asperity friction losses have not changed significantly in top dead center and bottom dead center regions due to low testing speed, and hydrodynamic power losses have occurred in the middle of the course. Lack of combustion reactions in such engines has resulted in compression leakages and unavailability of a quality oil film layer. Since there are no combustion reactions, the eccentric movement of the pistons of the compressed air engines is changed by the lubricating oil, engine speed, compression leaks, and viscosity parameters.