Te Mahi a ngā Mīhini Tīhiera i roto i ngā Waka Hou
Ko ngā miihini tīhiera tētahi o ngā momo miihini tahunga ā-roto e whakamahia whānuitia ana i roto i ngā waka hou, inā koa ngā waka arumoni, ngā SUV, me ētahi waka pāhihi e hiahia ana ki te whai huatanga nui me te taipana teitei. Kāore i rite ki ngā miihini penehīni, e whakawhirinaki ana ki te mura o te mura, ka mahi ngā miihini tīhiera i runga i te kaupapa o te mura kōpeketanga, ka mura te wahie nā te pāmahana teitei o te hau kōpeke. Nā te whanaketanga hangarau, kua maha ngā whakapainga kua pā ki ngā miihini tīhiera hou , kua kaha ake, kua penapena wahie, kua maeneene ake, ā, kua pai ake te taiao i ngā whakatupuranga o mua.
1. Ariā Taketake : Te tahunga me te Whakakā Kōpeketanga
Ko te kaupapa matua o te miihini tīhiera ko te pēhi i te hau i roto i te rango ki te pēhanga tino teitei. Mā tēnei pēhanga ka piki ake te pāmahana o te hau. Ina werohia te wahie tīhiera ki roto i tēnei hau wera hei kohu pai, ka mimiti, ka mura aunoa, me te kore he āwhina o te puru mura. Koinei te rerekētanga matua i waenga i te miihini tīhiera me te miihini penehīni.
Ko te ōwehenga kōpeketanga o te mīhini tīhiera he nui ake i te mīhini penehīni . Ka taea e ngā mīhini tīhiera hou te whai ōwehenga kōpeketanga mai i te 14:1 ki te 20:1 (i runga i te hoahoa me ngā whakaritenga tukunga/whai hua). Ko tēnei ōwehenga kōpeketanga teitei he mea nui ki te whai huatanga wera o te mīhini tīhiera, nā te mea ka teitei ake te ōwehenga kōpeketanga, ka nui ake te pūngao ka taea te tango mai i te tukanga tahunga.
2. Te Huringa Mahi a te Mīhini Tīhiera: Ngā Huringa Matua e Whā
Ko te nuinga o ngā waka hou e whakamahi ana i te miihini tīhiera wha-whiu. Ko te huringa ko:
a. Te Whiu Whakauru
Ka neke te piston mai i te Pokapū Mate Runga (TDC) ki te Pokapū Mate Raro (BDC), ka tuwhera te takirere whakauru, ā, ka tomo te hau hou ki roto i te rango. I roto i te miihini tīhiera, ko te hau te nuinga o te whakaurunga (kaua i te ranunga hau-wahie pērā i te miihini penehīni tikanga). I roto i te maha o ngā miihini hou, kua pēhia te hau e tomo mai ana e te turbocharger, ka whakanui ake i te nui o te hāora.
b. Whiu Kōpeketanga
Ka kati te takirere whakauru, ka neke te piston mai i te BDC ki te TDC, ā, ka pēhia te hau. I tēnei wāhanga, ka tino piki te pāmahana o te hau. Ka tata ki te mutunga o te pēhanga, ka tīmata te pūnaha werohanga ki te werohanga wahie i te pēhanga teitei.
c. Te Mana/Te Whānuitanga o te Whiu
Ka whakaranua te wahie werohanga ki te hau wera, ā, ka mura noa iho. Ka puta he pēhanga teitei i te tahunga, ka panaia te piston ki raro mai i te TDC ki te BDC. Koinei te whiu e whakaputa ana i te mana hei huri i te porowhita.
d. Te Whiu Pūngao
Ka huaki te takirere putanga hau, ka neke ake te piston mai i te BDC ki te TDC, ā, ka tukuna ngā hau putanga hau mā te putanga putanga hau ki te pūnaha putanga hau me ngā taputapu whakahaere tukunga.
E mano ngā wā e whakahokia ana tēnei huringa i ia meneti, i runga i te rpm o te mīhini. Ko te maeneene me te whai huatanga o te mīhini he mea nui ki te wā tika o te takirere, te nui me te wā werohanga wahie, me te whakahaere hau whakauru.
3. Te Tūranga o ngā Pūnaha Werohanga Hou: Te Werohanga Rerewē Noa me te Werohanga Maha-Wāhanga
Ko tētahi o ngā hurihanga nui rawa atu o ngā miihini tīhiera hou ko te whakamahinga o te pūnaha werohanga tika rēriwe noa. I roto i tēnei pūnaha, ka pupuhihia te wahie ki roto i tētahi "rēriwe" pēhanga teitei rawa (ngoipu kohikohi)—ka eke ki te 1.500 ki te neke atu i te 2.500 pae—kātahi ka tukuna ki ngā werohanga hiko i roto i ia rango.
Ngā painga o te tereina noa:
– He pai ake te whakakorikori kia tino tika ai te tahunga.
– He tino tika te whakahaere werohanga, e whakahaerehia ana e te ECU (Wāhanga Whakahaere Mīhini).
– He maha ngā āheinga werohanga: hei tauira, i mua i te werohanga, i te werohanga matua, me muri i te werohanga.
Mā te werohanga ā-wāhanga ka āwhina i te whakaiti i te patoto o te tīhiera, te whakaiti i ngā tukunga matūriki, me te whakapai ake i te whakamarie taraiwa. Mā te werohanga i mua i te tīmatanga o te tahunga ka pai ake te tīmatanga, engari mā te werohanga i muri i te tīmatanga ka āwhina i te whakahoutanga o te tātari matūriki (DPF) i raro i ētahi āhuatanga.
4. Turbocharger me Intercooler: Te Tāpiri Hau, Te Whakanui Ake i te Whai Hua
He maha ngā miihini tīhiera hou e whakamahi ana i ngā turbocharger hei whakanui ake i te tuku hau. Ka whakamahia e ngā turbocharger te kaha o ngā hau putanga hei huri i te tāpine e hono ana ki te compressor. Ka kōpeke te compressor i te hau whakauru, ka whakanui ake i tōna taumaha (hāora). Mā te nui ake o te hāora, ka taea e te miihini te tahu wahie me te whai hua, ka whakanui ake i te taipana me te mana me te kore e tino whakanui ake i te nekehanga o te miihini.
Nā te wera o te hau kōpeke, ka tāutahia he hau whakamātao (hau whakamātao whakauru) hei whakaheke i te pāmahana o te hau, hei whakanui ake i tōna kiato, hei whakaiti hoki i te tūponotanga o te tahunga kāore i oti. Mā te whakakotahitanga o te turbo me te hau whakamātao ka taea e ngā miihini tīhiera iti te whakaputa i te taipana teitei mai i ngā tere iti—he āhuatanga e pai ana ki ngā waka o ēnei rā.
5. Pūwero Hiko: Āwhina ki te Tīmata i ngā Āhuatanga Makariri
Kāore ngā miihini tīhiera e whakamahi ana i ngā puru mura, engari he maha e whakamahi ana i ngā puru mura hei āwhina i te tīmatanga i te wā e makariri ana te miihini. I ngā pāmahana iti, kāore e ranea te pēhanga anake hei whakaara ake i te pāmahana hau ki tētahi pūwāhi mura pumau. Ka whakamahanahia e ngā puru mura te rūma mura, te rohe rānei e karapoti ana i ngā werohanga, ka āwhina i te mura tuatahi. I roto i ētahi miihini hou, ka mahi hoki ngā puru mura mō te wā poto i muri i te tīmatanga o te miihini hei whakaū i te mura me te whakaiti i te paoa.
6. Whakahaere Tukunga: EGR, DOC, DPF, me te SCR
Ko te wero matua o ngā miihini tīhiera hou ko te whakatutuki i ngā paerewa tino pakari o ngā tukunga. Nā te mea ka tahuna te tīhiera i roto i te hau nui me ngā pāmahana teitei, ka puta he NOx (hauota waikura) me te matūriki (ngārara/PM). Hei whakatutuki i tēnei, ka whakamahia e ngā waka hou te huinga o ngā hangarau e whai ake nei:
– EGR (Whakahokinga Anō o te Hau Putanga): ka whakahokia ētahi o te hau putanga ki te tomokanga hau hei whakaiti i te pāmahana tahunga kia iti ai te NOx.
– DOC (Diesel Oxidation Catalyst): ka whakawairakau i te CO me te HC hei CO₂ me te H₂O, ā, ka āwhina anō hoki ki te whakaiti i te haunga me ētahi wāhanga kino.
– DPF (Tātari Matūriki Tīhiera): ka tātari i ngā matūriki/ngārara. Me "whakaora" te DPF i ia wā (te tahu i te ngārara kua kohia)—ka taea tēnei te noho puku, te noho kaha rānei mā te rautaki werohanga.
– SCR (Selective Catalytic Reduction): ka whakaiti i te NOx mā te rehu i te wai urea (e kiia ana ko AdBlue) ki roto i te hau putanga, kātahi ka tauhohe i roto i te whakakorikori hei whakaputa hauota me te mamaoa wai.
Mā tēnei huinga pūnaha ka nui ake te ma o te hinu tīhiera o ēnei rā, ahakoa he uaua ake, ā, me tika hoki te tiaki (hei tauira, he pai te kounga o te hinu tīhiera me te whakamahinga o te AdBlue i roto i te pūnaha SCR).
7. Te Tūranga o te ECU me ngā Pūoko: Ka "Ataahua" ngā Mīhini Tīhiera
Ahakoa he rite tonu ngā miihini tīhiera tawhito ki ngā tikanga māmā, ko ngā miihini tīhiera hou e whakawhirinaki nui ana ki ngā pūnaha hiko. Ka tukatukahia e te ECU ngā raraunga mai i ngā momo pūoko, pērā i te MAF/MAP (rerenga hau/pēhanga), ngā pūoko pāmahana, ngā pūoko porowhita me te porowhita kame, ngā pūoko hāora (i roto i ētahi pūnaha), tae atu ki te pūoko pēhanga reriwe wahie. Mā te whakamahi i ēnei raraunga, ka whakahaere te ECU i:
– Te wā me te roa o te werohanga
– Te pēhanga wahie i runga i te ara rerewē noa
– Te whakatuwheratanga o te EGR
– Mana Turbo (keeti ururua, turbo/VGT āhuahanga rerekē rānei)
– Rautaki whakaora DPF
Ko te mutunga mai he mura pumau ake i raro i ngā āhuatanga rerekē, he whakapaunga wahie ōhanga ake , me te mana tino pai me te iti o ngā tukunga.
8. Ngā Āhuatanga o ngā Mīhini Tīhiera Hou i roto i te Taraiwa
I roto i te whakamahinga o ia rā, e mōhiotia ana ngā miihini tīhiera hou mō:
– He taipana nui i ngā tere iti, he pai mō ngā kawenga taumaha me te whakaterenga tīmatanga kaha.
– He tino whai hua, nā te nui o te ōwehenga kōpeketanga me ngā āhuatanga mura whai hua.
– Te pakari, nā te mea ko te nuinga o te wā ka hangaia ngā wāhanga kia kaha ake te tu atu i te pēhanga pēhanga teitei.
– He māeneene ake, he marino ake i te tīhiera tawhito, nā te werohanga tika, te whakaiti i te miihini me te whakahaere āta mura.
Heoi anō, me whai kounga pai te hinu tīhi o ēnei rā, me tiaki hoki i te tātari, me te aro ki te pūnaha tukunga kia mau tonu ai te mahi tino pai, kia kore ai hoki e raru pērā i te aukati DPF, te pokanoa rānei ki te EGR.
Whakamutunga
Ko te kaupapa mahi o ngā miihini tīhi i roto i ngā waka hou e ahu mai ana i te whakakā kōpeketanga: ka kōpeketia te hau kia wera rawa, kātahi ka werowerohia te wahie, ka mura noa iho. Ko te mea e wehewehe ana i ngā tīhi hou i ngā whakatupuranga o mua ko ngā whanaketanga nui o ngā pūnaha werowero tereina noa, te whakakaha turbo, te whakahaere hiko o te ECU, me ngā taputapu whakahaere tukunga pēnei i te EGR, DPF, me te SCR. Mā tēnei huinga hangarau ka taea e ngā miihini tīhi hou te tuku i te taipana kaha, te whai huatanga wahie teitei , me te whakahaere tonu i ngā tukunga—kia mau tonu ai te whai huatanga i waenga i ngā tono whai huatanga me ngā ture taiao.
