Kinematics modeling of the gear-based crank mechanism engine regardless of the compressions ratio variations

Amir Sakhraoui; Maroua Saggar; Fayza Ayari; Rachid Nasri

doi:10.1038/s41598-024-53085-1

Kinematics modeling of the gear-based crank mechanism engine regardless of the compressions ratio variations

Sci Rep. 2024 Feb 2;14(1):2807. doi: 10.1038/s41598-024-53085-1.

Authors

Amir Sakhraoui¹, Maroua Saggar², Fayza Ayari³, Rachid Nasri⁴

Affiliations

¹ Department of Mechanical Engineering, LR-11-ES19 Applied Mechanics and Engineering Laboratory (LR-MAI), National Engineering School of Tunis, University of Tunis El Manar, 1002, Tunis, Tunisia. amir.sakhraoui@enit.utm.tn.
² Mechanical Laboratory of Sousse, Private Central Polytechnic School of Tunis, Centrale University, La Goulette, Tunis, Tunisia.
³ National Higher School of Engineers of Tunis (ENSIT), (99/UR/11-46), University of Tunis, 1002, Tunis, Tunisia.
⁴ Department of Mechanical Engineering, LR-11-ES19 Applied Mechanics and Engineering Laboratory (LR-MAI), National Engineering School of Tunis, University of Tunis El Manar, 1002, Tunis, Tunisia.

Abstract

In this work, geometric and kinematic modeling of the gear-based crank mechanism engine (GBCM) was performed. To this aim, a mechanical approach based on projective computational methods and mechanism theory laws is applied, to which a parametric study has allowed a conclusion on the geometrical and kinematic behaviors of the moving links. The study concluded that the kinematic quantities at connecting rod head are one-half of those at the piston top head. The extrinsic behavior like the stroke of the connecting rod head is twice the crank radius and the piston kinematic are identical to the conventional engine with the same crankshaft ratio regardless of the compression ratio and any gear wheel radius. Hence, all the extrinsic kinematic properties of a classic crankshaft mechanism of the fixed compression ratio engine remain valid for a gear-based crank mechanism engine and can be used for dynamic calculation purposes.