Choyamba, mphete ya mpweya. Mphete ya gasi imalumikizana mwachindunji ndi mpweya woyaka ndi kutentha kwambiri komanso kuthamanga kwambiri, ndipo kutentha kumakhala kokwera kwambiri panthawi yogwira ntchito. Mpweya wotentha kwambiri komanso wothamanga kwambiri umalowa mumphepete mwa pisitoni kuchokera pampata pakati pa khoma la silinda ndi pisitoni, ndikukumana ndi mafuta a injini omwe amabweretsedwa ndi kupopera kwa mphete ya pistoni, zomwe zimapangitsa kuti mafutawo ayambe kukhazikika komanso limbitsa; kuonjezera apo, injini ikasiya, jekeseni yomaliza Mafuta omwe amalowetsedwa m'chipinda choyaka sichiwotchedwa, ndipo pansi pa kutentha kotsalira kwa pisitoni, idzakhalanso coke ndi kulimba, ndipo pamapeto pake ma deposits a carbon adzapangidwa ndipo zoyikidwa mu piston ring groove. Iyi ndiye mfundo yopangira gasi mphete ya kaboni. Pokhapokha mu mphete ya mpweya, mafuta a injini omwe amabweretsedwa ndi kupopera kwa mphete ya pistoni ndi ochepa kwambiri, ndipo ambiri mwa iwo ndi carbon deposit yosungidwa ndi kuyaka kosakwanira kwa mafuta. Ndiko kunena kuti, ma depositi ambiri a kaboni omwe amaikidwa pa mphete ya gasi amayamba chifukwa cha mafuta, ndipo mawonekedwe ake ndi kuyaka kwa petulo zimakhudza mwachindunji kuchuluka ndi chikhalidwe cha ma depositi a kaboni.

Mphete ya pisitoni imangoyenda mmwamba ndi pansi m'mphepete mwa pisitoni, ndipo silindayo sikhala yozungulira kwenikweni. Pistoni imabwerera mmwamba ndi pansi mu silinda, ndipo mphete ya pistoni imakanizidwa nthawi zonse ndikutambasulidwa. Madipoziti a kaboni, akukanikizidwa nthawi zonse, sangathe kusungidwa, ma depositi a kaboni omwe ali pampata wakumbuyo amatha kukhalabe. Mwa kuyankhula kwina, ma depositi a kaboni amangotsala mbali imodzi ya mphete ya mpweya, ndipo n'zosatheka kutseka mphete ya mpweya kuti ife, ndipo sizingatheke kuchititsa injini kuwotcha mafuta. Nthawi yomweyo, ma depositi a kaboni amayikidwa kumbuyo, komwe kumachepetsa mpata wakumbuyo, koma kumatha kulimbikitsa chisindikizo ndikuchepetsa mphamvu yopopa.