Ukuhlaziywa Kokudluliselwa Kokushisa Ezinjinini Zokushisa Zangaphakathi
I-Pendahuluan
Injini yokushisa yangaphakathi (i-ICE) iyithuluzi lokuguqula amandla eliguqula amandla amakhemikhali kaphethiloli abe amandla omshini ngenqubo yokushisa ekamelweni lokushisa. Kule nqubo, ukudluliselwa kokushisa kudlala indima ebalulekile ngoba kunquma ukusebenza kahle, ukusebenza, ukukhishwa komoya, kanye nokuthembeka kwenjini. Ukushisa okukhiqizwa ukusha akuguquki ngokuphelele kube umsebenzi owusizo ku-crankshaft; okunye kulahleka ngamagesi okukhipha umoya, okunye kudluliselwa ezindongeni zesilinda, ama-piston, nasemakhanda esilinda, bese kukhishelwa ezinhlelweni zokupholisa nezokugcoba. Ngakho-ke, ukuhlaziya ukudluliselwa kokushisa ezinjinini zokushisa zangaphakathi kuyisisekelo esibalulekile ekwakheni izinjini ezisebenzisa amandla amaningi, ezinamandla, nezihlala isikhathi eside.
Imithombo Nezindlela Zokudlulisa Ukushisa
Ngokuvamile, ukushisa enjinini yokushisa yangaphakathi kuvela ekusabeleni kokusha kwengxube yomoya-kaphethiloli. Ngemva kokusha, izinga lokushisa legesi elisesilinda lingafinyelela ngaphezu kuka-2000 K ezimweni eziphakeme kakhulu, okudala i-gradient yokushisa ebalulekile phakathi kwegesi eshisayo kanye nezindawo zensimbi ezipholile. Ngenxa yalokho, ukushisa kugeleza kusuka kugesi kuya ezingxenyeni zenjini ngezindlela ezintathu eziyinhloko: ukuqhutshwa komoya, ukuhanjiswa komoya, kanye nemisebe.
Izindlela eziyinhloko zokudlulisa ukushisa zingafingqwa kanje:
1. Igesi eshisayo → indawo yegumbi lokusha (udonga lwesilinda, ikhanda lesilinda, indawo yepiston) ngokusebenzisa i-convection kanye nemisebe.
2. Ubuso begumbi lokusha → ingaphakathi lento ngokusebenzisa ukuqhutshwa.
3. Izinto ezibonakalayo → indawo ngokusebenzisa i-convection kuya ku-coolant (i-radiator) kanye namafutha okugcoba, bese ekugcineni emoyeni ozungezile.
Ukuqonda lezi zindlela kusiza onjiniyela ukuthi banqume izindawo ezibalulekile ezidinga ukupholisa okungcono noma izinto ezimelana nokushisa kakhulu.
I-Convection ku-Cylinder
I-Convection iyindlela eyinhloko ngaphansi kwezimo eziningi zokusebenza kwenjini. I-coefficient yokudlulisa ukushisa kwe-convection ekamelweni lokushisa ithonywa kakhulu yi-gas flow turbulence, isivinini se-piston, ukuma kwegumbi lokushisa, kanye nezimo zokushisa.
Ngesikhathi sokucindezela nokushisa, ukugeleza kwegesi kuba nokuphazamiseka okukhulu ngenxa yokunyakaza kwe-piston kanye nomklamo we-intake port, okubangela ukuzungeza nokuwa. Lokhu kuxokozela kwandisa i-heat transfer coefficient (h), ngaleyo ndlela kwandisa izinga lokudluliselwa kokushisa kusuka kugesi kuya odongeni. Kalula nje, izinga lokudluliselwa kokushisa kwe-convection lingabhalwa kanje:
\[
\dot{Q}_{conv} = hA(T_g – T_w)
\]
lapho \(A\) kuyindawo yokudlulisa ukushisa, \(T_g\) izinga lokushisa legesi, kanye \(T_w\) izinga lokushisa lodonga. Njengoba izinga lokushisa legesi lishintsha ngokushesha phakathi nomjikelezo, ukuhlaziywa okungokoqobo kuvame ukuba okwesikhashana (kushintsha ngesikhathi/isivinini sokuwa).
Ezifundweni zenjini, ukuhambisana kwe-empirical (isb., i-Woschni) kuvame ukusetshenziswa ukulinganisa i-\(h\) ngokusekelwe ekucindezelweni kwesilinda, izinga lokushisa legesi, kanye nesivinini sokugeleza esiyingqayizivele. Ukuhambisana okunjalo kubalulekile ngoba ukugeleza kwesilinda kuyinkimbinkimbi futhi kunzima ukukuxazulula ngokuhlaziya kuphela.
Imisebe Eshisayo Evela Emlilweni Nakumagesi Ashisayo
Ngaphandle kokushintshashintsha komoya, imisebe nayo iyasiza, ikakhulukazi ezinjinini zedizili nangaphansi kwezimo zomthwalo ophezulu. Ezinjinini zedizili, ukusha kokusabalalisa kukhiqiza inani elikhulu lomsi, okwandisa ukukhishwa kwegesi, okwenza imisebe ibe yinto ebaluleke kakhulu. Imisebe idluliselwa kusuka elangeni kanye nemikhiqizo yokusha iye ezindaweni zodonga lwegumbi lokusha.
Izinga lokudluliselwa kokushisa okukhanyayo ngokuvamile lilandela umthetho kaStefan-Boltzmann:
\[
\dot{Q}_{rad} = \varepsilon \sigma A(T_g^4 – T_w^4)
\]
nge-\(\varepsilon\) ukukhishwa okusebenzayo kwegesi/ilangabi kanye ne-\(\sigma\) i-Stefan–Boltzmann constant. Ngenxa yokuthi kuncike emandleni okushisa wesine, imisebe iyanda kakhulu lapho izinga lokushisa eliphakeme kakhulu liphezulu. Kodwa-ke, empeleni, ukulinganisa i-\(\varepsilon\) akulula ngoba kuthinteka ukwakheka kwegesi, izinhlayiya ze-soot, kanye ne-geometry yegumbi lomlilo.
Ukuqhutshwa Kwezingxenye Zomshini
Ukushisa okumuncwa ubuso begumbi lokusha kuzohamba kuye ngaphakathi kwezinto ngokusebenzisa ukuqhutshwa kwegesi. Izinto ezisetshenziswayo ngokuvamile ziyi-aluminium alloys (ama-piston, amakhanda athile esilinda) noma insimbi ephonswe kanye nensimbi (amabhlogo esilinda, ama-liners, ama-valve). Ukuqhutshwa kwegesi kuvezwa ngumthetho kaFourier:
\[
\dot{Q}_{cond} = -kA\frac{dT}{dx}
\]
lapho \(k\) kungukuqhutshwa kokushisa kwezinto. I-Aluminium inokuqhuba okuphezulu kunensimbi ephonswe, okuvumela ukuthi ikhiphe ukushisa ngokushesha, yehlise amazinga okushisa aphezulu endawo futhi inciphise ingozi yezindawo ezishisayo. Kodwa-ke, i-aluminium nayo inamandla aphansi okushisa aphezulu kunezinye izinto ezisekelwe ensimbini, ngakho-ke imiklamo idinga ukuvumelana phakathi kokushabalaliswa kokushisa nokuqina kwesakhiwo.
Ukuqhuba ugesi kubalulekile kuma-piston: ukushisa okuvela emqheleni we-piston kumele kudluliselwe emasongweni e-piston, esiketini, futhi ekugcineni ezindongeni zesilinda kanye namafutha. Uma indlela yokuqhuba ugesi inganele, i-piston ingaba nokukhula okukhulu, ukuguguleka okusheshayo, ngisho nomonakalo ngenxa yokuqhuma noma ukusha kwangaphambi kokushisa.
Ukudluliselwa Kokushisa Kuzinhlelo Zokupholisa Nokugcoba
Ukushisa okufinyelela ezindongeni zesilinda kanye nekhanda lesilinda kube sekudluliselwa ku-coolant (ijakethi yamanzi) nge-convection. Uhlelo lokupholisa lugcina izinga lokushisa lokusebenza kwenjini ngaphakathi kwebanga elifanele ukuqinisekisa ukujiya kukawoyela okuzinzile, ukusha okuphumelelayo, kanye nokuvimbela ukuwohloka kokushisa kwengxenye.
Ngakolunye uhlangothi, uwoyela wokugcoba usebenza njengendawo yokupholisa, ikakhulukazi kuma-piston (ngama-jet kawoyela), ama-bearings, kanye nezindawo ezihambisana nokushayisana okukhulu. Nakuba amandla okupholisa kawoyela ngokuvamile ephansi kune-coolant, indima yawo ibalulekile ekulawuleni amazinga okushisa endawo kanye nokuvimbela ukwehluleka kwe-tribological (ukuguguleka nokuqhekeka).
Ekuhlaziyweni kwamandla enjini, ukushisa kuvame ukuhlukaniswa kube: umsebenzi ophumelelayo, ukushisa ku-coolant, ukushisa ku-oyela, kanye ne-enthalpy yegesi yokukhipha umoya. Ubukhulu balezi zingxenyana buxhomeke ohlotsheni lwenjini, isilinganiso sokucindezela, isu lokusha, kanye nomklamo wesistimu yokupholisa.
Umphumela Wokudluliselwa Kokushisa Ekusebenzeni Kahle
Ukulahlekelwa ukushisa odongeni lwesilinda kunciphisa amandla atholakalayo ukuze kukhiqizwe umsebenzi. Ngokombono we-thermodynamic, izinjini ezinciphisa ukudluliselwa kokushisa odongeni (ngaphandle kokuletha izinkinga zokushisa) zinamandla okuba nokusebenza kahle kokushisa okuphezulu. Kodwa-ke, ukunciphisa ukudluliselwa kokushisa akulula ngaso sonke isikhathi ngoba amazinga okushisa ezingxenyeni kumele ahlale ngaphansi kwemingcele yezinto zokwakha kanye nokuthambisa.
Ezinye izindlela, njengezembozo zokuvimbela ukushisa kuma-piston noma emakhanda esilinda, zinganciphisa ukugeleza kokushisa ezintweni. Kodwa-ke, lezi zinguquko zingandisa amazinga okushisa kwegesi, okungenzeka kwandise ukwakheka kwe-NOx ezinjinini zikaphethiloli kanye nedizili futhi kwandise ingozi yokushayisana kwezinjini zikaphethiloli. Ngakho-ke, ukwenza ngcono ukudluliselwa kokushisa kuhilela njalo ukuhweba phakathi kokusebenza kahle, ukukhishwa kwegesi, kanye nokuqina.
Ukuhlaziywa Kwesikhashana Nokusatshalaliswa Kwezinga Lokushisa
Imijikelezo yenjini iyashesha (isb., i-2000 rpm isho ukujikeleza okungu-33,3 ngomzuzwana), ngakho-ke izinga lokushisa legesi liyashintshashintsha ngokushesha ngomjikelezo ngamunye. Izindawo zodonga zithola ukuguquguquka okuncane kwezinga lokushisa ngenxa yobuningi bokushisa bezinto ezibonakalayo. Ngakho-ke, ukuhlaziywa kokudluliselwa kokushisa ezinjinini ngokuvamile kudinga indlela yesikhashana: izinga lokushisa legesi njengomsebenzi wejubane le-crank, ukushintsha kwama-coefficients e-convection, kanye nezimo zemisebe eguquguqukayo.
Ukusatshalaliswa kwezinga lokushisa akufani. Indawo eseduze nevalvu yokukhipha umoya ivame ukuba yindawo eshisa kakhulu ngoba amagesi okukhipha umoya ashisa kakhulu futhi ageleza adlule ivalvu. Le ndawo eshisayo ingabangela ukuqhekeka kokushisa ekhanda lesilinda noma ku-valvu evuthayo uma ukupholisa kunganele. Ngakho-ke, ukwakheka kwejakethi yamanzi, ukukhethwa kwezinto zamavalvu, kanye nesu lokupholisa kubalulekile.
Imiphumela Yokuklama Namasu Okulawula
Ukuhlaziywa kokudluliselwa kokushisa kuqhuba izinqumo eziningana ezibalulekile zokuklama:
1. I-geometry yegumbi lokushiswa: ithinta indawo engaphezulu, ukuxokozela, kanye nokusatshalaliswa kokushisa. Amagumbi okushiswa anezindawo ezinkulu ezingaphezulu avame ukwandisa ukulahleka kokushisa.
2. Izinto zokwakha kanye nokwemboza: khetha ukuhanjiswa kokushisa okufanele kanye nokumelana nokushisa.
3. Uhlelo lokupholisa oluzivumelanisa nezimo: i-thermostat, iphampu kagesi eguquguqukayo, kanye nokulawula ukugeleza kokupholisa ukuze kulondolozwe izinga lokushisa elifanele emithwalweni eyahlukahlukene.
4. Ukuphathwa kokusha: isikhathi sokusha/sokufaka, i-EGR, kanye nesu lokuxuba ukuze kulinganiswe ukusebenza kahle kanye nokukhishwa kwegesi.
5. Ukulungiswa kokugcoba: i-piston oil jet kanye nomklamo wokujikeleza kwamafutha ukunciphisa amazinga okushisa e-piston kanye nama-bearing.
Isiphetho
Ukudluliselwa kokushisa enjinini yokushisa yangaphakathi kuyisenzakalo esiyinkimbinkimbi esihilela ukuhanjiswa kwegesi okuguquguqukayo kwamagesi angaphakathi kwesilinda, imisebe evela elangeni namagesi ashisayo, kanye nokuhanjiswa kwegesi ngokusebenzisa izingxenye zenjini kuya ezinhlelweni zokupholisa nezokugcoba. Ukuhlaziywa komsindo kwenza abaklami baqonde ukulahlekelwa amandla, balawule amazinga okushisa ezingxenye, futhi bathuthukise ukusebenza kahle ngenkathi begcina ukukhishwa kwegesi kanye nokuthembeka. Njengoba izimoto zesimanje ziqhubeka zifuna ukusetshenziswa kukaphethiloli kanye nokukhishwa kwegesi, ukwazi ukuhlaziywa kokudluliselwa kokushisa kuya ngokuya kubaluleka, kokubili ezinjinini ezivamile kanye nalezo ezinobuchwepheshe bamuva bokushisa.
Uma ufisa, ngingaqedela lesi sihloko ngalokhu okulandelayo: (1) isibonelo esilula sokubalwa kokushisa kodonga lwesilinda, (2) umdwebo ojwayelekile wokugeleza kwamandla (ibhalansi yokushisa) yenjini kaphethiloli vs. idizili, noma (3) uhlu lwezincwadi/izinkomba zejenali ukuqinisa isisekelo sesayensi.
