Simultaneous Shot-Peening of hard and soft particles for friction reduction in reciprocal sliding

Friction between mechanical components experiencing relative motion is responsible for about 20% of the total world energy consumption. In this work, an experimental study is presented to evaluate the effect of Simultaneous Shot-Peening (SSP) of hard and soft particles on friction reduction between mechanical components experiencing reciprocal motion, such as in piston ring and cylinder liner in internal combustion engines (ICE). A novel micro-shot peening device for simultaneous treatment with hard and soft particles is described, along with a reciprocal test rig. Total of 25 combinations of normal load and sliding speed were tested. Comparison between a Treated SSP and Reference specimens shows an average friction reduction of up to 33% with local maximum friction reduction of up to 65%.