Catalyst tswj
Kev ntsuam xyuas ntawm cov degree ntawm hnav ntawm lub catalyst, kws tshaj lij lub npe hu ua catalytic converter, uas yog tas li ua los ntawm on-board diagnostic system, muaj nyob rau hauv kev tshuaj xyuas cov kev hloov nyob rau hauv cov pa cov ntsiab lus nyob rau hauv lub tso pa gases ua ntej thiab tom qab lub catalyst.
Rau lub hom phiaj no, cov teeb liab xa los ntawm oxygen sensors (tseem hu ua lambda sensors) yog siv. Ib tug ntawm cov sensors yog ntsia rau pem hauv ntej ntawm nws 
catalyst thiab thib ob rear. Qhov sib txawv ntawm cov teeb liab yog vim qhov tseeb tias qee qhov ntawm cov pa oxygen hauv cov pa tso pa tawm los ntawm cov catalyst thiab yog li cov pa oxygen hauv cov pa tso pa tawm hauv qab ntawm cov catalyst. Lub peev xwm oxygen ntawm cov catalyst yog hu ua oxygen peev xwm. Nws txo qis thaum cov catalyst hnav, uas ua rau muaj kev nce ntxiv ntawm cov pa oxygen hauv cov pa tawm hauv nws. Lub on-board diagnostic system ntsuas cov pa muaj peev xwm ntawm lub catalyst thiab siv nws los txiav txim nws cov hauj lwm zoo.
Cov pa oxygen sensor ntsia ua ntej lub catalyst yog siv los tswj cov khoom sib xyaw. Yog hais tias qhov no yog qhov sib xyaw stoichiometric, uas qhov tseeb ntawm huab cua yuav tsum tau hlawv ib koob tshuaj roj ntawm ib lub sijhawm yog sib npaug rau qhov ntsuas theoretical, qhov hu ua binary sojntsuam. Nws qhia txog kev tswj hwm qhov sib xyaw ua ke yog nplua nuj lossis lean (rau roj), tab sis tsis yog los ntawm ntau npaum li cas. Qhov haujlwm kawg no tuaj yeem ua tau los ntawm qhov hu ua broadband lambda sojntsuam. Nws cov zis parameter, uas characterizes cov ntsiab lus ntawm cov pa oxygen nyob rau hauv lub tso pa gases, tsis yog ib tug voltage uas hloov stepwise (raws li nyob rau hauv ib tug ob-txoj hauj lwm sojntsuam), tab sis ib tug yuav luag linearly nce lub zog tam sim no. Qhov no tso cai rau cov muaj pes tsawg leeg ntawm cov pa pa yuav tsum tau ntsuas nyob rau hauv ib tug ntau yam ntawm cov huab cua piv, tseem hu ua lub lambda piv, li no lub sij hawm broadband sojntsuam.
Lub lambda sojntsuam, ntsia tom qab lub catalytic converter, ua lwm yam haujlwm. Raws li qhov tshwm sim ntawm kev laus ntawm cov pa oxygen sensor nyob rau hauv pem hauv ntej ntawm lub catalyst, cov sib tov tswj raws li nws cov teeb liab (hluav taws xob raug) ua leaner. Qhov no yog qhov tshwm sim ntawm kev hloov cov yam ntxwv ntawm kev sojntsuam. Lub luag haujlwm ntawm qhov thib ob oxygen sensor yog los tswj qhov nruab nrab ntawm qhov sib xyaw ntawm qhov kub hnyiab. Yog hais tias, raws li nws cov teeb liab, lub cav tswj xyuas pom tias qhov sib tov yog lean heev, nws yuav ua rau kom lub sij hawm txhaj tshuaj kom tau raws li qhov yuav tsum tau muaj ntawm cov kev tswj xyuas.
