Iiplagi ze-spark, ezaziwa ngokuba ziiplagi zomlilo, ziya kusebenza njenge-pulse yokukhupha i-piezoelectric ene-voltage ephezulu ukusuka kwi-high-voltage lead (iplagi yomlilo), eya kuphula umoya phakathi kwee-electrode zeeplagi ze-spark, ivelise ii-spark zombane ukuze zivuthele umxube wegesi kwisilinda. Iimeko ezisisiseko zenjini yokusebenza okuphezulu: i-spark eqinileyo yamandla aphezulu, umxube ofanayo, umlinganiselo woxinzelelo oluphezulu. Iimoto ezineenjini zokutsha zangaphakathi zihlala zisebenzisa ipetroli kunye ne-diesel fuel. Kwimarike yeemoto zaseTshayina, iimoto zepetroli zithatha indawo enkulu. Iinjini zepetroli zahlukile kwiinjini zedizili kuba ipetroli inendawo yokutsha ephezulu (malunga nama-400 degrees), nto leyo efuna ukutsha okunyanzelekileyo ukuze kuvuthele umxube. Ngokukhupha phakathi kwee-electrode ukuvelisa ii-spark, injini yepetroli idlula kumxube wepetroli kunye negesi ukuze ivelise amandla, kodwa njengoko ipetroli yepetroli nakwindawo enobushushu obuphezulu kunzima ukuyitshisa ngokukhawuleza, ukuze ivuthele ngexesha elifanelekileyo kuyimfuneko ukusebenzisa "umlilo" ukuze ivuthele. Apha ukutsha kwe-spark ngumsebenzi we-"spark plug".
