Firikwensin matsi na iska (ManifoldAbsolutePressureSensor), daga baya ana kiransa MAP. An haɗa shi da nau'in abin sha tare da bututu mai ƙura. Tare da nau'ikan saurin injin daban-daban, yana iya fahimtar canjin injin a cikin nau'in abin sha, sannan ya canza canjin juriya a cikin firikwensin zuwa siginar wutar lantarki, wanda ECU za ta iya amfani da shi don gyara adadin allura da kusurwar lokacin kunna wuta.
A cikin injin EFI, ana amfani da firikwensin matsa lamba don gano ƙarar abun ciki, wanda ake kira tsarin allurar D (nau'in girman saurin gudu). Firikwensin matsa lamba yana gano ƙarar ci ba a gano kai tsaye kamar firikwensin kwararar ci ba, amma an gano shi a kaikaice. A lokaci guda kuma, abubuwa da yawa suna shafar shi, don haka akwai wurare daban-daban a cikin ganowa da kiyayewa daga firikwensin kwararar abinci, kuma laifin da aka haifar shima yana da nasa musamman.
Firikwensin matsa lamba yana gano cikakken matsi na nau'in abin sha a bayan magudanar. Yana gano canjin cikakken matsa lamba a cikin manifold gwargwadon saurin injin da lodi, sannan ya canza shi zuwa wutar lantarki ta sigina ya aika zuwa sashin sarrafa injin (ECU). ECU tana sarrafa ainihin adadin allurar mai gwargwadon girman ƙarfin siginar.
Akwai nau'ikan na'urori masu auna matsa lamba masu shigowa da yawa, kamar nau'in varistor da nau'in capacitive. Ana amfani da Varistor sosai a cikin tsarin allura na D saboda fa'idodinsa kamar lokacin amsawa mai sauri, daidaiton ganowa mai girma, ƙaramin girman da shigarwa mai sauƙi.
Hoto na 1 yana nuna alaƙa tsakanin firikwensin matsa lamba na varistor da kwamfutar. FIG. 2 yana nuna ƙa'idar aiki na nau'in varistor nau'in firikwensin matsa lamba, da R a cikin FIG. 1 shine nau'in resistors R1, R2, R3 da R4 a cikin FIG. 2, waɗanda ke samar da gadar Wheatstone kuma an haɗa su tare da diaphragm na silicon. Silicon diaphragm na iya lalacewa a ƙarƙashin cikakken matsa lamba a cikin manifold, wanda ya haifar da canjin juriya na juriya na juriya R. Mafi girma da cikakken matsa lamba a cikin manifold, mafi girma da nakasawa na silicon diaphragm kuma mafi girma da canji na ƙimar juriya na juriya R. Wato, canje-canjen injina na diaphragm na siliki an canza su zuwa siginar lantarki, waɗanda aka haɓaka ta hanyar haɗin haɗin gwiwa sannan kuma fitarwa zuwa ECU.
