Tlhahlobo ea Thermal ea Lienjene tsa Mollo oa ka Hare
Tlhahlobo ea mocheso oa lienjene tsa ho chesa ka hare (ICEs) e bohlokoa bakeng sa ho utloisisa kamoo matla a lik'hemik'hale a mafura a fetoloang matla a mechini, hammoho le kamoo mocheso o ajoang, o sebelisoang le ho lahleha kateng nakong ena. Lienjene tsa ho chesa ka hare—ebang ke likoloing, lijenereithara, kapa lits'ebetsong tsa indasteri—li sebetsa tlas'a mocheso o phahameng le khatello, kahoo ts'ebetso ea tsona, bokhoni, likhase tse tsoang moeeng le ts'epo ea likarolo li susumetsoa haholo ke litšobotsi tsa tsona tsa mocheso. Ka tlhahlobo ea mocheso, baenjiniere ba ka ntlafatsa moralo oa kamore ea ho chesa, maano a ho pholisa, khetho ea thepa le taolo ea likhase tse tsoang moeeng.
1. Mehopolo ea Motheo ea Matla le Mocheso Mechining
Ha e le hantle, enjene ea ho tuka ka hare e fetola matla a lik'hemik'hale a mafura hore e be mocheso ka karabelo ea ho tuka. Mocheso ona o eketsa matla a ka hare a khase ka hare ho silindara, o hlahisa khatello e sutumetsang piston (bakeng sa enjene e busetsang) kapa e khanna turbine (bakeng sa enjene ea turbine ea khase). Leha ho le joalo, ha se mocheso oohle o fetoloang mosebetsi o molemo. Bongata ba oona bo lahleha ka:
1. Khase ea mosi (tahlehelo ea mosi): Matla a mocheso a etsoa ka khase ea mosi.
2. Sistimi ea ho pholisa (tahlehelo ea sepholisi): Mocheso o monngoa ke mabota a silindara, hlooho ea silindara le likarolo tse ling ebe o fetisetsoa sepholising kapa moeeng.
3. Mahlasedi a kantle le convection: Mocheso o lokollwa tikolohong ho tloha hodima mochini.
4. Tahlehelo ea mechine: Le hoja e se mocheso feela, khohlano e hlahisa mocheso 'me e fokotsa mosebetsi o atlehang.
Tlhahlobo ea mocheso e leka ho theha tekano ea matla: karolo efe ea matla a mafura e fetohang matla a brake, ke bokae bo lahleheloang ke sesebelisoa se pholileng, ke bokae bo lahlehang e le khase ea mosi, le hore na ke bokae bo lahlehang ka mekhoa e meng.
2. Potoloho e Loketseng ea Thermodynamic le Potoloho ea 'Nete
Ho utloisisa boitšoaro ba mocheso ba enjene, mohlala o motle oa potoloho o atisa ho sebelisoa:
– Otto baesekele bakeng sa dienjene tsa peterole (ho hotetsa tlhase).
– Potoloho ea diesel bakeng sa lienjene tsa diesel (ho ignition ea compression).
– Dual Cycle e le motsoako oa litšobotsi tsa Otto le Diesel.
– Brayton bakeng sa diturbine tsa khase.
Potoloho e loketseng e nka ts'ebetso e ka fetoloang le ho tuka hang-hang, ntle le tahlehelo ea mocheso le khohlano. Leha ho le joalo, lienjeneng tsa 'nete, ho na le liphapang tse kholo, mohlala:
– Ho tuka ho nka nako (ho tuka ka sekhahla se lekanyelitsoeng).
– Phetisetso ea mocheso maboteng a silindara e bohlokoa haholo.
– Ho na le ho phatloha ha khase (ho dutla ha khase ka pela mehele ya piston).
– Ts'ebetso ea ho hula le ho ntša mosi e baka tahlehelo ea ho pompa.
– Thepa ea mocheso ea likhase e fetoha ho latela mocheso.
Ka hona, tlhahlobo ea mocheso ea lienjene tsa 'nete e hloka tokiso—ebang ke ka mekhoa ea ho bona lintho ka mahlo, mehlala ea 1D/3D, kapa lintlha tsa liteko.
3. Phetisetso ea Mocheso ka Silindara
Phetiso ea mocheso ho tloha likhase tse tukang ho ea maboteng a silindara e etsahala ka mekhoa e meraro: phetisetso ea motlakase, phetisetso ea motlakase, le mahlaseli. Ho ICE, phetisetso ea motlakase ke eona e hlahelletseng ka ho fetisisa, kaha phallo e matla ka phapusing ea phetisetso ea mocheso e potlakisa phetisetso ea mocheso.
Mabaka a mang a ka sehloohong a susumetsang phetiso ea mocheso:
– Mocheso oa khase le lebota: Ha phapang ea mocheso e le kholo, sekhahla sa phetisetso ea mocheso se ba seholo.
– Pherekano: E susumetsoa ke moralo oa kou, sebopeho sa piston, ho potoloha, ho putlama le lebelo la enjene.
– Kgatelelo le botenya ba khase: Keketseho nakong ya kgatello le ho tuka, e leng se eketsang bokgoni ba phetisetso ya mocheso.
– Karolelano ea khatello: Ka kakaretso e eketsa katleho ea mocheso, empa hape e eketsa mocheso o phahameng e le hore mojaro oa mocheso likarolong o eketsehe.
Mehlala ea phetisetso ea mocheso ka har'a silindara hangata e sebelisa likamano tsa boiphihlelo, joalo ka Woschni kapa Hohenberg, ho hakanya coefficient ea convection ho latela li-variable tsa ts'ebetso ea enjene.
4. Tlhahlobo ea Mocheso oa Likarolo tse Bohlokoa
Likarolo tsa mochini li ba le maemo a phahameng a mocheso le lipotoloho tse pheta-phetoang tsa mocheso, tse ka lebisang mokhathaleng oa mocheso, ho fetoha ha sebopeho, kapa ho hloleha ha thepa. Likarolo tsa bohlokoa li kenyelletsa:
– Piston: Moqhaka wa piston o fumana mocheso ka ho toba ho tswa ho tukang. Ho phodisa ho fihlellwa ka di-jet tsa oli, di-galleries tsa ho phodisa piston, le moralo wa thepa.
– Hlooho ea silindara le li-valve: Li-valve tsa mosi le sebaka se potileng litulo tsa tsona li fumana mocheso o phahameng ka ho fetisisa ho tsoa likhase tse chesang. Thepa e hanelang mocheso le pholiso e sebetsang hantle ke tsa bohlokoa.
– Mochini o silindara: O tlameha ho ntsha mocheso ha o ntse o boloka setlolo le ho fokotsa ho sotha.
– Turbocharger (haeba e le teng): Turbine e sebetsa mochesong o phahameng oa khase ea mosi; ho hlokahala ho nahana ka ho pholisa le ho khetha li-alloy tse hanelang mocheso.
Tlhahlobo ea mocheso oa likarolo hangata e sebelisa li-simulation tsa conduction (mohlala, tlhahlobo ea likarolo tse lekanyelitsoeng/FEA) tse nang le meeli ea convection ea khase le coolant. Sepheo ke ho netefatsa hore mocheso o phahameng ka ho fetisisa o ka tlase ho meeli ea thepa le ho fokotsa khatello ea mocheso.
5. Sistimi ea ho Pholisa le Tsamaiso ea Thermal
Kaha mocheso o mongata o lokela ho tlosoa ho thibela enjene ho chesa haholo, sistimi ea ho pholisa e fetoha karolo ea bohlokoa ea tlhahlobo ea mocheso. Lienjene tsa sejoale-joale li sebelisa:
– Ho phodisa metsi (jakete ya metsi) ka radiator, pompo ya phodisang, thermostat le fene.
– Ho phodisa moya dienjeneng tse itseng (dienjeneng tse nyane, dienjeneng tse ding tsa dithuthuthu).
Phapang ea bohlokoa: ho pholisa ka matla ho fokotsa mocheso oa enjene 'me ho ka fokotsa katleho ea mocheso hobane mocheso o mongata o lahleheloa ke sesebelisoa se pholisang. Ka lehlakoreng le leng, ho pholisa ho sa lekaneng ho eketsa kotsi ea ho kokota (peteroleng), pele ho hotetsoa, ho senyeha ha oli le tšenyo ea likarolo.
Mehopolo ea tsamaiso ea mocheso ea sejoale-joale e leka ho boloka enjene mochesong o motle ka ho fetisisa: e phahameng ka ho lekaneng bakeng sa ts'ebetso e ntle le mesi e kotsi, empa e tlase ka ho lekaneng bakeng sa ts'epo. Maano a kenyelletsa:
– Pompo e phodisang e fetofetohang.
– Thermostat ea elektroniki.
– Pholiso e reretsoeng libakeng tse mahlonoko.
– Taolo ea phallo ea EGR (exhaust gas recirculation) ho fokotsa mocheso oa ho tuka le NOx.
6. Bokgoni ba Mocheso le Tekanyo ya Matla
Bokgoni ba mocheso ba enjene ke feela karolelano ea mosebetsi o hloekileng le matla a kenang ho tsoa mafura. Likoloing, hangata e hlalosoa e le:
– Bokgoni bo bontshitsweng ba mocheso: bo itshetlehile ka mosebetsi o ka hara silindara.
– Bokgoni ba ho futhumatsa ka brake: bo itshetlehile hodima matla a shaft ya tlhahiso.
Tekanyo e tloaelehileng ea matla bakeng sa enjene e tloaelehileng e bontša hore ke hoo e ka bang 25–40% feela ea matla a mafura a fetoloang matla a ka sebelisoang, 'me a setseng a lahleheloa ke mosi le pholiso. Lienjeneng tsa diesel tsa sejoale-joale, tsa theknoloji e phahameng, bokhoni bo ka ba holimo haholo, empa meeli ea motheo e ntse e le teng ka lebaka la thermodynamics (mohlala, moeli o loketseng oa Carnot) le meeli e sebetsang (ho tuka, khohlano, mosi o tsoang le ho tšoarella ha thepa).
Maiteko a ho ntlafatsa bokgoni ba mocheso a kenyeletsa:
– Eketsa karolelano ea khatello (ka meeli e kokotang/e sa tloaelehang ea ho chesa).
– Fokotsa tahlehelo ea mocheso ka ho koahela mocheso (li-coat tse thibelang mocheso).
– Ho sebedisa matla a kgase ya mosi ka ho tjhaja ka turbocharging, turbocompounding, kapa ho kgutlisa mocheso o lahlilweng (mohlala, potoloho ya Rankine).
– Ntlafatsa nako ea ho chesa, AFR (karolelano ea moea le mafura), le leano la ho enta.
7. Kamano pakeng tsa Tlhahlobo ea Thermal le Mesi e Hlahang
Mocheso oa ho tuka o susumetsa haholo ho thehoa ha mesi e kotsi:
– NOx e eketseha mochesong o phahameng le keketsehong ea oksijene.
– CO le HC lia eketseha haeba ho cha ho sa fella kapa mocheso o le tlase haholo.
– Dikaroloana (mosili), haholo-holo ka diesel, di angoa ke ho tswakwa ha sebaka le mocheso.
Ka hona, tlhahlobo ea mocheso e ke ke ea aroloa le maano a taolo ea mesi e kotsi. Mohlala, EGR e theola mocheso o phahameng, ka hona e thibela NOx, empa e ka eketsa mosi haeba e sa leka-lekanngoe ka ho kopanya le ho oxidation hantle.
8. Mekhoa ea Tlhahlobo: Liteko le Liketsiso
Tlhahlobo ea mocheso e etsoa ka motsoako oa:
1. Teko ea enjene
Lekanya mocheso oa sesebelisoa se pholileng, oli, khase ea mosi, le likarolo (u sebelisa li-thermocouple, lik'hamera tsa IR, kapa li-sensor tse khethehileng). Lintlha tsena lia hlokahala bakeng sa netefatso ea mohlala.
2. Ketsiso ea 1D (ketsiso ea potoloho ea enjene)
E etsa mehlala ea lits'ebetso tse ka har'a silindara, phallo ea ho kena/ho ntša mosi, le ho chesa ha lefats'e. E potlakile bakeng sa ho lekola liparamente tsa ts'ebetso le litekanyo tsa mocheso.
3. Kamore ea ho tuka ea CFD 3D
E hlahloba lintlha tsa pherekano, ho kopanya, malakabe le kabo ea mocheso. E thusa haholo bakeng sa ho ntlafatsa moralo oa kamore ea ho tuka le enjene.
4. FEA ea sebopeho sa mocheso
Bala kabo ea mocheso le khatello ea mocheso likarolong, haholo-holo lipiston, lihlooho tsa lisilindara, li-manifold le li-turbocharger.
Ho kopanngoa ha mekhoa ena ho fella ka moralo o sebetsang hantle le o tšepahalang.
Qetello
Tlhahlobo ea mocheso ea lienjene tsa ho besa ka hare ke ea bohlokoa bakeng sa ho ntlafatsa katleho, ho fokotsa mesi e tsoang ka hare, le ho netefatsa botšepehi ba likarolo libakeng tsa ts'ebetso tsa mocheso o phahameng. Ka ho utloisisa phetisetso ea mocheso ka har'a silindara, ho leka-lekana ha matla, le tsamaiso ea ho pholisa, baenjiniere ba ka etsa liqeto tsa moralo tse nang le tsebo e batsi—ho tloha ho jiometri ea kamore ea ho besa le thepa ho ea ho litsamaiso tsa ho pholisa le taolo ea ts'ebetso ea enjene. Tsoelo-pele ea theknoloji ea simulation (CFD/FEA) le li-sensor tsa tekanyo li ntlafatsa bokhoni ba tlhahlobo haholoanyane, li nolofalletsa ntlafatso e potlakileng le e nepahetseng haholoanyane ho fihlela litlhoko tsa kajeno tsa taolo ea ts'ebetso ea matla le mesi e tsoang ka ntle.
Haeba o lakatsa, nka fetola sengoloa sena hore se be sa thuto haholoanyane (se felletseng ka di-equation tsa motheo, ditshupiso, le dikgaolo tse nyane tsa mokgwa wa ho bala) kapa se sebetse haholoanyane bakeng sa merero ya kabelo/thesis.
