Mathematical Modeling of a Hydrodynamic Lubrication of a Piston Skirt Considering the Deformations and Dynamics of the Piston Displacement People Friendship University of Russia

Format:

Book

Conference/Event

Author/Creator:

Smirnov, Sergeĭ (Sergeĭ Anatolʹevich), 1958- author.

Contributor:

Vorobyev, Alexander

Zaev, Ivan

Conference Name:

SAE Powertrains, Fuels & Lubricants Digital Summit (2021-09-28 : Live Online, Pennsylvania, United States)

Language:

English

Physical Description:

1 online resource cm

Place of Publication:

Warrendale, PA SAE International 2021

Summary:

One of the important problems in piston design is to minimize friction losses during piston motion. This is possible if liquid friction is supported in piston skirt-liner junction. Therefore determination of the friction type in this junction is required. This problem can be divided into a set of coupled subproblems: determination of piston secondary motion; determination of piston deformation under mechanical and thermal loads; calculation of the hydrodynamic forces acting on piston from oil layer. Application of widely used general purpose software tools, which can solve these tasks separately and their iterative use for coupling can result in enormous amount of time to optimize final piston design. The coupled mathematical model and software modules were developed and computational studies were performed for lubrication process.The main attention is paid to the solution of elastohydrodynamic problem. The solution of the Reynolds equations in two-dimensional formulation is performed with account for change of oil layer thickness due to hydrodynamic pressures. The finite-difference approximation and Newton method of solution of non-linear system of equations are applied. Also the change in oil viscosity is considered. If the contact point/surface of piston with liner appears during solution of the system of equations, this surface is excluded from calculation. In a contact region the system of linear equations for elastic deformations is solved. The forces in a contact region are determined for correct estimate of their effect on deformations in the region of hydrodynamic friction. Important aspect of the efficient model implementation is correct specification of the compliance matrix for mesh nodes of the piston skirt, which can be obtained from CAD model of the piston.The results of the simulations are given for piston with diameter 130 mm and profile of skirt is determined.Developed mathematical model allows to study several effects on piston design/friction: crank mechanism, mounting clearance, oil properties, engine operation conditions

Notes:

Vendor supplied data

Publisher Number:

2021-01-1141

Access Restriction:

Restricted for use by site license