Injini inoda kusveta mumhepo yakawanda panguva yekushanda. Kana mhepo isina kusefa, guruva rakarembera mumhepo rinosvetwa muhumburumbira, iyo inomhanyisa kupfeka kweboka repiston uye cylinder. Zvimedu zvakakura zvinopinda pakati pepistoni necylinder zvinogona kukonzera zvakakomba "kudhonza humburumbira", iyo inonyanya kukosha munzvimbo dzakaoma uye dzine jecha dzekushanda. Iyo sefa yemhepo inoiswa pamberi pecarburetor kana pombi yekupinza kusefa kunze guruva nejecha mumhepo, kuve nechokwadi chekuti mweya wakakwana uye wakachena unopinda mucylinder.
Zvinoenderana neiyo filtration musimboti, mafirita emhepo anogona kukamurwa kuita sefa rudzi, centrifugal mhando, oiri yekugezesa mhando uye composite mhando.
Munguva yekugadzirisa, iyo pepa sefa chinhu hachifanirwe kucheneswa mumafuta, zvikasadaro bepa sefa chinhu chinotadza, uye zviri nyore kukonzera tsaona yekumhanyisa. Panguva yekugadzirisa, chete nzira yekuzunguza, iyo yakapfava bhurashi yekubvisa nzira (yekukwesha pamwe nekuunyana) kana iyo yakadzvanywa mweya blowback nzira inogona chete kushandiswa kubvisa guruva uye tsvina yakanamatira pamusoro pebepa sefa chinhu. Kune iyo coarse sefa chikamu, guruva riri muguruva rinounganidza chikamu, mashizha uye pombi yedutu inofanira kubviswa nenguva. Kunyangwe kana ichigona kunyatsochengetedzwa nguva dzese, iyo bepa sefa chinhu haigone kudzoreredza kuita kwayo kwepakutanga, uye kuramba kwayo kwemhepo kunowedzera. Naizvozvo, kazhinji, kana iyo bepa sefa chinhu chinoda kuchengetedzwa kechina, chinofanira kutsiviwa nechinhu chitsva chesefa. Kana iyo bepa sefa element yakatsemuka, yakapwanyika, kana iyo sefa bepa uye yekupedzisira cap yakabviswa, inofanira kutsiviwa nekukasira.