Simulation of a New Spark-ignition Internal Combustion Rotary Engine 2009-36-0327
In the present work a mathematical model was developed simulating the performance of a new rotary spark-ignition internal combustion engine with variable speed displacers. In this engine, four displacers rotate concentrically, in an annular space, at variable and phased angular velocities, thus creating distinct variable-volume working spaces between them. Concentric shafts are driven individually by the displacers. An innovative connecting rod mechanism imposes phased variable angular speeds to the shafts and, consequently, to the displacers. The mechanism also offers a convenient way of compression ratio control, at constant power shaft angular speed. This new engine follows the stages of intake, compression, combustion, expansion and exhaust. The integral equations of energy and mass conservation, in their time derivative form, are applied to the control volumes. Gas properties are supposed to be uniformly distributed in the control volumes. Pressure and temperature variations inside the engine are obtained through the numerical integration of the conservation equations, with the help of equations of heat transfer rate between gas and wall, of gas flow through the exhaust and intake ports and clearances between movable parts, the equations of volume variation inside each chamber, and chemical equations and stoichiometry. A preliminary analysis was carried out against first engine test bed results.