[i][/i]THE IMPACT OF MICROGEOMETRY BEARING SURFACE OF THE PISTON ON THE PARAMETERS OF OIL FILM

Abstract

The formation of oil film is possible under certain parameters of microgeometry cooperating components the main node of the internal combustion engine, which is a piston-pin-piston rings. In addition, this node is primarily responsible for the formation of mechanical losses. It is advisable to reduce friction losses in the piston-cylinder group lead to an increase in the overall efficiency of the engine and thus reduce the fuel consumption. One way of achieving these objectives is modification of microgeometry of the piston-bearing surface, which cooperates with the cylinder wall. The geometry of the gap between the piston skirt and the cylinder liner greatly affects the friction loss inside the engine. This means that the friction loss is much more affected by the area covered by the oil film separating the mating elements than its thickness. The method to reduce the area covered by the oil film is a modification of the bearing surface of the piston by adjusting the profile. The supporting surface, which performs a reciprocating motion relative to the strokes of the cylinder liner ensure the continuity of the oil film with the smallest possible value of the friction losses at the node piston-cylinder. This paper presents the results of simulation leading which aim to determining the parameters oil film on the friction loss for the modified bearing surface of the piston.

The impact of microgeometry pistons with a stepped bearing surface for the friction loss of the internal combustion engine

“…Adopted ennobling layer shape on the supporting surface is a continuation of earlier studies [14][15][16][17]. Friction losses can be reduced by such shaping of the gap between the piston and the cylinder (figure 1), which will provide continuous generation of the oil film separating the mating surfaces.…”

“…Step-shaped gap can be obtained by the application of the H shaped graphite layers on the supporting surface of the piston. This will give the stepped profile which is characterized by a favorable tribological properties of the cylinder-piston kinematic couple fluid friction conditions, and use of graphite can expected advantageous properties in terms of boundary friction [15][16].…”