Increasing the efficiency of rotary piston engines by the use of the diesel cycle

The article deals with the task of increasing the efficiency of rotary piston engines by implementing an economical diesel cycle in a module with a three-arc epitrochoid and an external gearing kinematics scheme. The necessity of the diesel cycle is caused by the need of reducing specific fuel consumption in rotary piston engines that are currently widely used in light aviation, mostly for remotely piloted aircraft. The Wankel rotary piston engine with a two-arc epitrochoid, though having a number of advantages over traditional piston engines, is inferior to them in efficiency, particularly in partial load modes. The implementation of the diesel cycle in а cycloidal piston engine with a three-arc epitrochoid makes it possible to reduce specific fuel consumption by 30% while retaining the listed positive qualities, as well as to use diesel fuel which is preferable for high-altitude aircraft due to lesser tendency to gas formation in pipelines. The engine stator inner loop is made up by three arcs of the epitrochoid that form three working chambers equally-spaced along the perimeter, which provides a decrease of the stator thermal deformation during the operation of the engine. A method is developed to determine the geometric parameters of a rotary piston engine with a three-arc epitrochoid, and design work is carried out in the КОМPAS-3D code for a 50 h. p. diesel engine to be used in light aviation and as a drive of electrical generators, pumps and compressors for ground application.