Effect of the Geometric Profile of Top Ring on the Tribological Characteristics of a Low-Displacement Diesel Engine

Abstract

The present study aims to analyze the influence of the geometric profile of the compression ring on the tribological properties of the lubricant. Additionally, the influence of the rotation speed and the engine load on the state of the lubricant is evaluated. For this study, a single-cylinder diesel engine is taken as the basis, from which a CAD model of the combustion chamber-piston assembly was made. In addition, the conditions in the cylinder chamber were analyzed when the engine operates at a rotation speed of 3000, 3300, 3600, and 3900 rpm, and a load of 1.5, 3.0, 4.5, and 6.0 N. The calculations were developed using the OpenFOAM® simulation software. The results obtained show that changes in the geometric profile of the ring can contribute to reducing the hydrodynamic friction force by 13% and the friction force caused by roughness by 61%. This implies a decrease in the power lost by friction. In general, the modification of the geometric profile allowed a reduction of 21% in the lost power associated with friction. Additionally, it was observed that the shape of the profile allows to reduce the pressure in the lubricant by 65% and obtain a greater thickness of the lubrication film. On average, an increase of 300 rpm and 1.5 N in the speed and load of the engine causes the friction force and power losses to increase by 45% and 10%. The above results imply that the geometric profile of the compression ring can improve tribological performance in the engine, allowing a reduction in fuel and better lubricant performance.

Investigation of the top compression ring power loss and energy consumption for different engine conditions

“…The contribution of surface topography on measured friction through CFD predictions was presented and discussed. The work of Duarte Forero et al [26] also provided numerical and experimental predictions for different ring profiles. They also compared the analytical predictions with measured results using the strain gauge method showing good agreement.…”

Numerical Methodology for Determining the Energy Losses in Auxiliary Systems and Friction Processes Applied to Low Displacement Diesel Engines

“…The viscous friction force is determined from the model proposed by Goksem and Hargreaves [47], as shown in Equation (17). (17) where c pv , r cc , v e and F n,v are the pressure viscosity coefficient, combined radius of curvature, entrainment velocity, and normal force, respectively.…”

“…The sources of friction losses are located in the interactions between the cylinder liner and the piston skirt, the camshaft, and the bearings. Based on the prominent contribution of friction losses, different investigations have been carried out to minimize energy losses through different strategies such as oil system heating [16], low viscosity oil [17,18], smooth contact surfaces [19], and coating implementation [20,21].…”

Performance assessment and economic perspectives of integrated PEM fuel cell and PEM electrolyzer for electric power generation

“…However, water electrolyzers only account for 4% of the worldwide hydrogen production [ 4 ], which highlights the importance of research in this area. As a short-term alternative, this green hydrogen source can be implemented for partial fuel substitution in internal combustion engines or turbines to improve the overall performance while reducing the pollutant emissions [ 5 , 6 , 7 ]. Cells construction is categorized by their electrolyte in alkaline, molten carbonate, solid oxide, and Proton Exchange Membrane (PEM); however, PEM type stands as a suitable technology in energy applications due to significant advantages such as compactness, operation flexibility, large production rates, hydrogen purity, and high effectiveness [ 8 ].…”