Kune injini huru yegungwa, mhete yepiston uye cylinder liner inokosha friction pair, uye zvakanaka kumhanya-mukati uye kushanda pakati pavo kwakakosha zvikuru kune injini huru. Kune echinyakare aruminiyamu-yakavharidzirwa piston mhete, hapana dambudziko munguva yekushandisa yakakwirira-sarufa mafuta. Mushure mezvose, iyo sulfur yemukati mune yakakwira-sarufa mafuta inobatsira kuzora pakati pepiston mhete uye silinda liner. Mushure mekushandiswa kwemafuta mashoma-sarufa, iyo firimu yemafuta pa cylinder liner haina kunaka sepakutanga, kunyange zvazvo kushandiswa kwepamusoro-soro nhamba cylinder lubricating mafuta haigoni kubvisa zvachose chiitiko ichi. Izvi zvinotungamira mukupfeka nekukurumidza kwealuminum-yakavharwa piston mhete, izvo zvinokanganisa friction pair, kuwedzera kupfeka pacylinder liner, uye kupfupisa hupenyu hwesevhisi. Kana iyo yakakosha kukosha kwecylinder lubricating mafuta haina kuwedzera panguva iyi, kupfeka kuchakwidziridzwa. Muchiitiko ichi, kushandiswa kwe cermet piston rings kuchavandudza kusamira kwepiston mhete, kuderedza friction coefficient, kuderedza zvakanyanya kukanganisa kwekushanda kweiyo friction pair, uye kurebesa hupenyu hwebasa repiston mhete uye silinda liner.