THEORETICAL STUDIES ON THE INFLUENCE OF KINEMATICS ON THE WORKFLOW OF A CRANKLESS ENGINE

Abstract

Modern requirements for internal combustion engines focus on increasing efficiency, reducing specific fuel consumption, and lowering the level of toxic emissions. One promising direction of development is the use of connecting-rod-free mechanisms, whose kinematic features can significantly influence the engine’s performance. Specifically, the absence of a traditional connecting-rod transmission alters the piston motion, the character of dwelling at the top and bottom dead centers, the magnitude of side forces, and the level of mechanical friction losses. This opens up opportunities to decrease energy losses, improve gas-exchange conditions, and achieve more complete combustion of the fuel–air mixture.

The article presents an analysis of the kinematic and dynamic characteristics of various designs of crankless engines. Theoretical studies demonstrate that changes in the piston trajectory, as well as the profiles of velocity and acceleration, impact heat release and the indicator parameters of the cycle. A comparative analysis with classical crank-slider mechanisms confirms that the elimination of side forces leads to reduced specific mechanical losses and vibrational loads, along with a potential increase in power output and thermal efficiency.

Additionally, it is important to note that the efficiency of connecting-rod-free mechanisms largely depends on the manufacturing accuracy and synchronization of moving components, as well as on the choice of materials that provide the required stiffness and wear resistance under increased loads. Another critical aspect is the optimization of geometric parameters of the piston-motion profile to achieve the desired thermodynamic characteristics across a wide range of operating conditions. Aligning the kinematics of the drive with the processes of mixture formation and combustion can lead to a more uniform pressure field in the cylinder and a reduction of local thermal stresses in the combustion chamber components. These advancements create opportunities for the development of advanced power units that can combine high efficiency, reliability, and environmental safety.

The obtained results indicate the feasibility of further studies of connecting-rod-free kinematic schemes as a basis for creating new generations of engines with improved energy and environmental performance. It is recommended to give special attention to experimental validation of theoretical models, assessment of actual mechanical losses, and durability of drive components.