Isikhathi se-valve esiguquguqukayo. Yiziphi izinzuzo? Imaphi amakhefu?
Ukuhlala njalo kwe-valve kulo lonke uhla lwesivinini senjini kuyisixazululo esishibhile kodwa esingasebenzi kahle. Ukushintsha kwesigaba kunezinzuzo eziningi.
Ekufuneni amathuba okuthuthukisa i-piston, izinjini zomlilo zangaphakathi ezinemivimbo emine, abaklami bahlala bethula izixazululo ezintsha zokuthuthukisa amandla, banwebe isivinini esiwusizo, banciphise ukusetshenziswa kukaphethiloli kanye nokunciphisa ukukhishwa kwentuthu. Emzabalazweni wokuthuthukisa izinqubo zokushiswa kukaphethiloli, onjiniyela bake basebenzisa isikhathi se-valve esishintshashintshayo ukuze bakhe izinjini ezisebenza kahle nezingangeni imvelo. Izilawuli zesikhathi, ezithuthukise kakhulu inqubo yokugcwalisa nokuhlanza isikhala ngaphezu kwamaphistoni, zibonise ukuthi zingabambisene abahle kakhulu babaklami futhi zabavulela amathuba amasha ngokuphelele.
Ezixazululweni zakudala ngaphandle kokushintsha isikhathi se-valve, amavalvu enjini enemivimbo emine avuleka futhi avaleke ngokomjikelezo othile. Lo mjikelezo uphindaphindwa ngendlela efanayo inqobo nje uma injini isasebenza. Kuwo wonke uhla lwesivinini, indawo ye-camshaft (ama), noma indawo, ukwakheka kanye nenani lamakhamera ku-camshaft, noma indawo nokuma kwezingalo ze-rocker (uma ifakiwe) akushintshi. Njengomphumela, izikhathi ezikahle zokuvula nokuhamba kwevalvu kuvela kuphela ebangeni elincane kakhulu le-rpm. Ngaphezu kwalokho, azihambisani namanani alungile futhi injini isebenza kahle kakhulu. Ngakho-ke, isikhathi se-valve esethwe efekthri siwukuyekethisa okufika kude lapho injini isebenza kahle kodwa ayikwazi ukukhombisa amakhono ayo eqiniso mayelana nokuguquguquka, ukuguquguquka, ukusetshenziswa kukaphethiloli kanye ne-exhaust emissions.
Uma izakhi zethulwa kulolu hlelo olungaguquki, oluvumela ukuguqulwa kwemingcele yesikhathi, khona-ke isimo sizoshintsha kakhulu. Ukunciphisa isikhathi se-valve kanye nokuphakama kwe-valve ebangeni eliphansi nelimaphakathi, ukwelula isikhathi se-valve nokwandisa ukuphakama kwe-valve ebangeni lesivinini esikhulu, kanye “nokufinyezwa” okuphindaphindiwe kokulinganisa isikhathi kwe-valve ngesivinini esisondele kakhulu, kungandisa kakhulu ububanzi besivinini lapho imingcele yesikhathi se-valve ilungile. Empeleni, lokhu kusho i-torque eyengeziwe kuma-revs aphansi (injini eguquguquka kangcono, ukusheshisa okulula ngaphandle kokwehla), kanye nokuzuza i-torque ephezulu phezu kwebanga elibanzi lokuvuselela. Ngakho-ke, esikhathini esidlule, ekucacisweni kobuchwepheshe, i-torque ephezulu yayixhunywe ngesivinini esithile senjini, futhi manje itholakala kakhulu ebangeni elithile lejubane.
Ukulungiswa kwesikhathi kwenziwa ngezindlela ezihlukahlukene. Ukuqhubekela phambili kwesistimu kunqunywa ukuklanywa kwe-variator, i.e. isici esiphezulu esibophezelekile ekushintsheni amapharamitha. Ezixazululweni eziyinkimbinkimbi kakhulu, yisistimu yonke elawulwa yikhompyutha, kucatshangelwa izici eziningi ezahlukene. Konke kuncike ekutheni udinga ukushintsha kuphela isikhathi sokuvula ama-valve noma ukushaywa kwabo. Kubalulekile futhi ukuthi izinguquko zenzeke kungazelelwe noma zihamba kancane.
Kuhlelo olulula (VVT), i-variator, i.e. i-elementi eyenza ukuthuthwa kwe-angular ye-camshaft ifakwe ku-camshaft drive pulley. Ngaphansi kwethonya lokucindezela kawoyela futhi ngenxa yamakamelo aklanywe ngokukhethekile ngaphakathi kwesondo, umshini ungazungezisa ihabhu nge-camshaft efakwe kuyo ngokuhlobene nendlu yamasondo, eyenziwa yisici sokushayela isikhathi (iketango noma ibhande elinamazinyo). Ngenxa yobulula balo, uhlelo olunjalo lushibhile kakhulu, kodwa alusebenzi. Bezisetshenziswa, phakathi kwezinye, iFiat, PSA, Ford, Renault neToyota kwezinye izinhlobo. Uhlelo lwe-Honda (VTEC) luletha imiphumela engcono kakhulu. Kuze kufike ku-rpm ethile, ama-valve avulwa ngamakhamera anamaphrofayili akhuthaza ukushayela okushelelayo nokonga. Uma ijubane elithile leqiwe, isethi yamakhamera ayashintsha futhi ama-lever acindezela amakhamera, okunomthelela ekushayeleni kwezemidlalo okunamandla. Ukushintsha kwenziwa uhlelo lwe-hydraulic, isignali inikezwa isilawuli se-electronic. Ama-hydraulics nawo anomthwalo wemfanelo wokuqinisekisa ukuthi ama-valve amabili kuphela isilinda ngasinye asebenza esigabeni sokuqala, nawo wonke amavalvu amane esigabeni sesibili. Kulokhu, hhayi kuphela izikhathi zokuvula ama-valve ezishintshayo, kodwa futhi nokushaywa kwabo. Isixazululo esifanayo esivela kwaHonda, kodwa ngoshintsho olubushelelezi esikhathini se-valve sibizwa ngokuthi i-VTEC. Izisombululo eziphefumulelwe yiHonda zingatholakala kwaMitsubishi (MIVEC) nakuNissan (VVL).
Kuhle ukwazi: okunikezwayo okungelona iqiniso. Kukhona abakhwabanisi ku-inthanethi! Umthombo: TVN Turbo / x-news
