Decreasing the Contact Surface between Piston and Cylinder at the Heat Engines by Rotary-Percussion

Abstract:

Nowadays the surface fine finishing processes ensure, according to the quality of the initialsurface, the initial quality of the cut metal, the operating mode used for processing, the value of roughness with values between Ra = ( 0.4 .. . 0.02) μm. This leads to the reduction of the size of the layer deformed in the previous processing, and to the decrease of the micro-hollows of the resulted roughness serving as lubricant stores contributing to a decrease in the abrasion resistance of the contact surface of the cylinder. From this context it results that bearing area or rather the work area tends towards 100%. This study will present a method of plastic deforming of the inner cylindrical surface by rotary-percussion. I intend to apply this plastic deformation between the honing operation for the scalping of the heat engines cylinders and the finishing honing. The micro-hollows created by percussion will provide oil deposits to eliminate the dry friction, and their density on the cylinder surface will contribute to reducing the load-bearing work surface. The load-bearing work surface obtained with this process will be the total surface minus the surface of the concavities executed through rotary percussion. This procedure applied to the final machining operation by honing the cylindrical surfaces aims at replacing the finishing honing with lapping thus eliminating the running operation at the commissioning of the heat engine. The process has several technological and economic advantages, such as: the malleability of the metal which the cylinder is built of can be higher, the wear of the piston’s surface will decrease the effect of polishing between the piston and the cylinder , the engine will be able to work at higher speeds because the effect of lubricating the contact surfaces will be enhanced; the elimination of the running operation will decrease the cost and time of the installation parameters specified by the manufacturer, the micro-hollows are not compatible with each other so that the oil in the concavities is not blown by the burning gases before the piston passes by them.

• Periodical: Advanced Materials Research (Volume 1036)
• Pages: 619-624
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.1036.619
• Online since: October 2014
• Authors: Daniel Chirita*
• Keywords: Boring, Concavities, Plastic Deformation, Rotary-Percussion, Roughness

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