M'mainjini oyatsa, kupulumutsa mafuta komanso kutulutsa mpweya sikungatheke popanda kupezeka kwa kafukufuku wa lambda. Chifukwa cha masensa awa, kuwonongeka kwa injini kumachepetsedwa kwambiri komanso kukhala kosangalatsa kugwiritsa ntchito.
Lambda probe, yomwe imadziwikanso kuti sensa ya okosijeni, imakhala ndi ntchito yoyezera kusiyana pakati pa zomwe zili mu mpweya wotulutsa mpweya ndi mpweya womwe uli m'chilengedwe.
Sensa iyi imatchedwa dzina lake ku chilembo λ (lambda) kuchokera ku zilembo zachi Greek, zomwe zimagwiritsidwa ntchito kuyimira kufanana pakati pa chiŵerengero chenicheni cha mafuta a mpweya ndi chiŵerengero choyenera (kapena stoichiometric) chosakaniza. Pamene mtengo uli wocheperapo ( λ ) zikutanthauza kuti kuchuluka kwa mpweya kumakhala kochepa kwambiri, kotero kuti kusakaniza kumakhala kolemera. Pamene zosiyana zimachitika ( λ > 1 ), chifukwa chokhala ndi mpweya wochuluka, kusakaniza kumanenedwa kukhala kosauka.
Chiŵerengero choyenera kapena stoichiometric, pogwiritsa ntchito injini ya mafuta monga chitsanzo, chiyenera kukhala 14.7 magawo a mpweya ku gawo limodzi la mafuta. Komabe, gawoli silikhala lokhazikika nthawi zonse. Pali zosintha zomwe zimakhudza ubalewu, kuchokera ku chilengedwe - kutentha, kupanikizika kapena chinyezi - kupita ku kayendetsedwe ka galimoto yokha - rpm, kutentha kwa injini, kusiyana kwa mphamvu zofunikira.
The lambda kafukufuku, podziwitsa injini kasamalidwe zamagetsi za kusiyana kwa mpweya zili mu mpweya utsi ndi kunja, amalola kusintha kuchuluka kwa mafuta jekeseni mu chipinda kuyaka.
Cholinga ndi kukwaniritsa mgwirizano pakati pa mphamvu, chuma chamafuta ndi mpweya, kubweretsa kusakaniza pafupi kwambiri ndi ubale wa stoichiometric. Mwachidule, kupangitsa injini kuti igwire ntchito bwino momwe mungathere.
Zimagwira ntchito bwanji?
Kufufuza kwa lambda kumagwira ntchito bwino kwambiri pa kutentha kwakukulu - osachepera 300 ° C - komwe kwatsimikizira kuti malo ake abwino ali pafupi ndi injini, pafupi ndi manifolds otulutsa mpweya. Masiku ano, ma probe a lambda angapezeke pafupi ndi chosinthira chothandizira, chifukwa ali ndi kukana komwe kumawalola kuti azitenthedwa popanda kutentha kwa mpweya wotuluka.
Pakadali pano, injini zimatha kukhala ndi ma probe awiri kapena kupitilira apo. Mwachitsanzo, pali zitsanzo zomwe zimagwiritsa ntchito ma probes a lambda omwe amapezeka kale komanso pambuyo pa chothandizira, kuti athe kuyeza mphamvu ya chigawochi.
Lambda probe imapangidwa ndi zirconium dioxide, zinthu za ceramic zomwe zikafika 300 ºC zimakhala kondakitala wa ayoni wa oxygen. Mwanjira imeneyi, kafukufukuyo amatha kuzindikira pogwiritsa ntchito kusinthasintha kwamagetsi (kuyezedwa mu mV kapena millivolts) kuchuluka kwa mpweya umene umapezeka mu mpweya wotulutsa mpweya.
Magetsi ofikira pafupifupi 500 mV akuwonetsa kusakanikirana kowonda, pamwamba pake kumawonetsa kusakanikirana kolemera. Ndi chizindikiro chamagetsi ichi chomwe chimatumizidwa ku injini yoyang'anira injini, ndipo imapanga kusintha kofunikira pa kuchuluka kwa mafuta omwe amalowetsedwa mu injini.
Palinso mtundu wina wa kafukufuku wa lambda, womwe umalowa m'malo mwa zirconium dioxide ndi titanium oxide-based semiconductor. Izi sizikusowa kutchulidwa kwa mpweya wa okosijeni kuchokera kunja, chifukwa zimatha kusintha mphamvu zake zamagetsi malinga ndi kuchuluka kwa mpweya. Poyerekeza ndi masensa a zirconium dioxide, masensa opangidwa ndi titanium oxide amakhala ndi nthawi yayitali yoyankha, koma kumbali ina, amakhala omvera komanso amakhala ndi mtengo wapamwamba.
Anali Bosch yemwe adapanga kafukufuku wa lambda kumapeto kwa zaka za m'ma 1960 moyang'aniridwa ndi Dr. Günter Bauman. Ukadaulo uwu unayamba kugwiritsidwa ntchito pagalimoto yopanga mu 1976, mu Volvo 240 ndi 260.
Zolakwa ndi zolakwika zambiri.
Masiku ano, kafukufuku wa lambda alibe mbiri yabwino, ngakhale kufunikira kwake sikungatsutse. Kulowetsedwa kwake, nthawi zambiri kumakhala kosafunikira, kumachokera ku zizindikiro zolakwika zopangidwa ndi injini zamagetsi zamagetsi.
Masensa awa ndi osagwirizana kwambiri kuposa momwe amawonekera, kotero kuti, ngakhale zizindikiro zolakwika zokhudzana ndi iwo zikuwonekera, zimatha chifukwa cha vuto lina mu kasamalidwe ka injini, kuwonetsera ntchito ya sensa. Monga kusamala komanso kuchenjeza za kuwonongeka kwa galimoto, kuyendetsa injini yamagetsi kumapereka cholakwika cha sensor.
Pakusinthana, ndikwabwino kusankha zida zoyambirira kapena zodziwika bwino. Kufunika kwa gawoli ndikofunikira pakugwira ntchito moyenera komanso thanzi la injini.