# Ngā Rerekētanga i waenga i ngā Mīhini Otto me ngā Mīhini Tīhiera
Ko ngā miihini mura ā-roto te pūtake o te nuinga o ngā waka e whakamahia ana e tātou i ia rā, tae atu ki ngā motuka, ngā taraka, ngā poti, me te nuinga o ngā taputapu taumaha. He maha ngā momo miihini mura ā-roto, engari ko ngā mea e rua e tino rongonui ana ko te miihini Otto me te miihini Tīhiera. Ahakoa he rerekē te mahi a ēnei e rua, e whakawhirinaki ana rāua ki te kaupapa matua o te tahu wahie i roto i te rango hei whakaputa mana. Ka matapakihia e tēnei tuhinga ngā rerekētanga matua i waenga i ngā miihini Otto me Tīhiera, e kapi ana i ngā āhuatanga o te hoahoa, te whakahaere, te mahi, me te whai huatanga o te wahie.
## He Hītori Poto mō ngā Mīhini Otto me te Tīhiera
I hangaia tuatahitia te mīhini Otto e Nikolaus Otto i te tau 1876. He mīhini mura ā-roto wha-wāhanga tēnei e whakamahi ana i te penehīni. I tapaina tēnei mīhini ko "Otto" i muri i tōna kaihanga.
I tētahi atu taha, i hangaia te miihini tīhiera e Rudolf Diesel i te tau 1892. Ka whakamahia e tēnei miihini te wahie tīhiera, ā, e mōhiotia ana mō tōna pai o te wera. I whakamahia te ingoa tīhiera hei whakahonore i tōna kaihanga.
## Mātāpono mahi
### Mīhini Otto
E whakahaerehia ana te mīhini Otto i runga i te huringa Otto, e whā ngā whiu: te whakauru, te kōpeketanga, te mana, me te whakaputanga.
1. Whakaurunga: I tēnei whiu, ka huaki te takirere whakauru, ka neke te piston ki raro, ka mimiti i te ranunga hau me te wahie ki roto i te rango.
2. Pēhanga: Kua kati ngā takirere whakauru me ngā takirere whakaputa hau, ā, ka neke te piston ki runga, ka pēhanga i te ranunga hau-wahie.
3. Mana: Ina tae te piston ki te pokapū mate o runga (TDC), ka mura te ranunga hau-wahie i te puru mura, ka puta he pahūtanga ka pana i te piston ki raro, ka whakaputa mana.
4. Putanga hau: Ka neke ake anō te piston, ka panaia te hau putanga hau i roto i te rango mā te takirere putanga hau.
### Mīhini Tīhiera
Ka mahi ngā miihini tīhiera i runga i te huringa tīhiera, ā, e whā ngā whiunga rite ki te miihini Otto, engari ko te rerekētanga matua ko te huarahi e whakaranua ai te wahie me te tahunga:
1. Whakaurunga: Ka huaki te takirere whakauru, ka heke te piston ki raro, ka mimiti i te hau parakore ki roto i te rango.
2. Pēhanga: Kua kati ngā takirere whakauru me ngā takirere whakaputa hau, ā, ka pēhia e te piston te hau ki tētahi taumata tino tiketike, ka puta he pāmahana tino teitei.
3. Mana: Ka werohia tika te wahie tīhiera ki roto i te hau kōpeke i roto i te rango. Nā te tino pāmahana o te hau, ka mura tonu te wahie, ka puta he pahūtanga e pana ana i te piston ki raro, ka whakaputa mana.
4. Putanga hau: Ka neke ake te piston, ka panaia te hau putanga hau i roto i te rango mā te takirere putanga hau.
## Te Whai Huatanga me te Ōhanga o te Wera
### Te Whai Hua o te Wera
He nui ake te whai hua o ngā miihini tīhiera i ngā miihini Otto. Nā te mea he nui ake ngā ōwehenga kōpeketanga o ngā miihini tīhiera, ka nui ake te whai huatanga o te wera. Ko te tikanga o te whai huatanga wera nui ake he iti ake te pūngao e ngaro ana i te wera, ā, he nui ake te pūngao e hurihia ana hei mana miihini.
### Te Whai Hua o te Wahie
Ko te whai huatanga o te wahie tētahi o ngā painga matua o ngā miihini tīhiera. He nui ake te kaha o te wahie tīhiera i te penehīni, arā, ka taea e ia te whakaputa i te kaha nui ake mō ia rita o te wahie. Hei tāpiri, nā te nui ake o te whai huatanga o te wera, he iti ake te wahie e whakamahia ana e ngā miihini tīhiera i ngā miihini Otto.
Heoi, he nui ake te utu o te wahie tīhi i te penehīni i ētahi rohe, ā, ko te tikanga me nui ake te tiaki me te kaha o ngā miihini tīhi. Ko ngā miihini Otto ia, he māmā ake te hoahoa me te tiaki, ahakoa he nui ake te whakapaunga wahie.
## Ngā Tukunga me te Taiao
### Mīhini Otto
Ko te tikanga, he nui ake ngā tukunga o ngā waikura hauota (NOx) me ngā warowaihā ka puta mai i ngā miihini Otto nā te iti o te pāmahana tahunga me te nui ake o te ranunga wahie-penehīni. Ahakoa ka taea e te hangarau whakawhiti catalytic te whakaiti i ēnei tukunga, he nui ake te pānga o ngā miihini Otto ki te parahanga o te hau i ngā miihini tīhiera.
### Mīhini Tīhiera
He nui ake ngā matūriki ka puta mai i ngā miihini tīhiera, e mōhiotia ana ko te pungarehu, ā, he nui ake ngā tukunga NOx. Hei whakatika i tēnei, he maha ngā miihini tīhiera hou kua whakauruhia ki ngā tātari matūriki me ngā pūnaha whakaiti whakaterenga whiriwhiri (SCR) e whakamahi ana i te urea hei whakaiti i te NOx. Ahakoa he iti ake ngā tukunga CO2 mai i ngā miihini tīhiera i ērā mai i ngā miihini Otto, he wero taiao te nui o ngā tukunga NOx me ngā matūriki puehu.
## Mahi
### Mīhini Otto
Ko te tikanga, he nui ake te tere o te miihini (RPM) o ngā miihini Otto i ngā miihini tīhiera. Nā tēnei ka pai ake mō ngā waka e hiahia ana ki te whakaterenga tere me te mahi nui, pērā i ngā motuka hākinakina me ētahi atu waka māmā.
### Mīhini Tīhiera
Ko ngā miihini tīhiera he nui ake te taipana i ngā tere iti iho. Nā tēnei ka pai mō ngā waka taumaha me ngā tono arumoni e hiahia ana ki te kaha kume nui, pērā i ngā taraka, ngā pahi, me ngā taputapu taumaha.
## Ngā Whakamahinga me ngā Taupānga
### Mīhini Otto
Nā te āhua o te mahi, ko ngā miihini Otto te mea e whakamahia whānuitia ana i roto i ngā waka māmā me ngā taputapu iti. Ko ngā motuka pāhihi, ngā motopaika, me ētahi mīhini iti e whakamahi ana i ngā miihini Otto. Ko ngā painga o te miihini Otto mō te whakatere me te tere he mea nui ki te whiriwhiri i tēnei momo miihini mō ngā waka māmā.
### Mīhini Tīhiera
Nā te pai o te whakamahinga o te wahie me te taipana teitei, ko ngā miihini tīhiera te mea e whakamahia whānuitia ana i roto i ngā waka taumaha me ngā taputapu ahumahi. He maha ngā taraka, ngā pahi, ngā taputapu taumaha, me ngā kaipuke e whakamahi ana i ngā miihini tīhiera. Hei tāpiri, he whānuitia te whakamahinga o ngā miihini tīhiera i roto i ngā tipu hiko me ngā mīhini ahumahi nā te mea he pai te whakamahinga mō te wā roa.
## Whakamutunga
Ko ngā miihini Otto me ngā miihini tīhiera he pou e rua o te ao miihini mura ā-roto, he painga me he ngoikoretanga tō ia miihini. He pai ngā miihini Otto, me ō rātou mahi teitei me ngā tere hurihuri teitei, mō ngā waka māmā me ngā waka hākinakina, ko ngā miihini tīhiera ia, me ō rātou mahi wahie me te taipana teitei, he pai mō ngā waka taumaha me ngā tono ahumahi.
Ahakoa ngā wero taiao e pā ana ki ngā momo miihini e rua, kei te haere tonu te hangarau ki te whakapai ake i te taiao o ngā momo miihini e rua. Ko te whiriwhiri i waenga i te miihini Otto me te miihini Diesel e whakawhirinaki ana ki ngā hiahia motuhake o te kaiwhakamahi e pā ana ki te mahi, te whai huatanga, me te whakamahinga. Mā te mārama ake ki ēnei rerekētanga, ka taea e tātou te whakatau whai whakaaro ake i te wā e whiriwhiri ana i te miihini e pai ana ki ā tātou hiahia.
