ʻO nā pūkuniahi, i ʻike nui ʻia ʻo ke ahi, e hana ma ke ʻano he puʻupuʻu o ka piezoelectric kiʻekiʻe-voltage discharge mai kahi kiʻekiʻe-voltage alakaʻi (ke ahi plug), ka mea e wāwahi ai i ka lewa ma waena o nā electrodes o nā pahu kukui, e hana ana i nā uila uila e hoʻā i ka hui kinoea i loko o ka cylinder. ʻO nā kūlana kumu o ka mīkini hana kiʻekiʻe: kiʻekiʻe ka ikehu kūpaʻa paʻa, hui pū ʻia, kiʻekiʻe compression ratio. Hoʻohana maʻamau nā kaʻa me nā ʻenekini puhi ahi i ka ʻaila a me ka wahie diesel. Ma ka mākeke kaʻa o Kina, noho nui nā kaʻa ʻaila. ʻOkoʻa nā ʻenekini ʻaila mai nā ʻenekini diesel no ka mea ʻoi aku ka kiʻekiʻe o ka ʻaila ʻaila (ma kahi o 400 degere), kahi e pono ai ka hoʻā ʻana i ka hui. Ma o ka hoʻokuʻu ʻana ma waena o nā electrodes e hana i nā ahi ahi, ʻo ka ʻaila engine ma o ka wahie a me ke kinoea hui ʻana i ka manawa e hoʻoulu ai i ka mana, akā e like me ka wahie gasoline a hiki i kahi kiʻekiʻe wela ka paʻakikī i ka hoʻopau ʻana, i mea e hoʻohana ai i ka manawa kūpono e hoʻohana i ka "ahi" e puhi. Ma ʻaneʻi ka hana "spark plug".
