Chidzidzo cheThermodynamic paInjini dzeDiesel neInjini dzePeturu
Pendauluan
Injini yekupisa mukati inyanzvi huru inoshandura simba remakemikari remafuta kuita simba remagetsi kuburikidza nekupisa mukati mesilinda. Mhando mbiri dzinonyanya kushandiswa mumotokari uye mashandisirwo akasiyana-siyana emaindasitiri imota yepeturu (spark ignition/SI) uye injini yedhiziri (compression ignition/CI). Kunyange zvazvo dzose dzichivimba nefour-stroke cycle (mumagadzirirwo akawanda) uye nheyo dzekutanga dzethermodynamic, kune misiyano yakakosha mukugadzirwa kwemusanganiswa, nzira yekupisa, hunhu hwekupisa, uye nekudaro, kushanda zvakanaka. Kudzidza kwethermodynamics kunotibatsira kunzwisisa kuti nei mainjini edhiziri achiwanzoshanda zvakanyanya, nei mainjini epeturu aine hunhu hwakasiyana hwekupindura uye hwekudzoka, uye kuti maparamendi akadai secompression ratio, tembiricha, kumanikidzwa, uye kurasikirwa zvinosarudza sei mashandiro.
Thermodynamics Yekutanga yeInjini Dzemukati Dzekupisa
Zvakanaka, mashandiro einjini anowanzo ongororwa kuburikidza nedanho re thermodynamic rakarongwa rinoita kuti zvinhu zvive nyore. Chinangwa hachisi chekutevedzera zvakanyatsojeka ruzivo rwekupisa, asi kupa hurongwa hwekuongorora simba remagadzirirwo emagetsi pakushanda zvakanaka. Huwandu hwakakosha muchidzidzo ichi hunosanganisira:
1. Chiyero chekudzvanya (r): chiyero chevhoriyamu yesilinda kana piston iri pakati pepasi kusvika pakati pepamusoro. Chiyero chekudzvanya chinokanganisa tembiricha yekupedzisira yekudzvanya nekumanikidzwa, nokudaro zvichisarudza kushanda zvakanaka.
2. Kupinza kupisa (Q_in) uye kubuda kwekupisa (Q_out): muchirevo chenguva yakakodzera, kupinda kwekupisa kunoitika panguva yekutsva (kana kuwedzera kupisa) uye kubuda kwekupisa kunoitika panguva yekuramba kupisa.
3. Basa reNet (W_net): musiyano uripo pakati pebasa rekuwedzera nebasa rekudzvanya.
4. Kushanda zvakanaka kwekupisa (η_th): chiyero chekushanda kwemagetsi nekupisa, kureva kuti η_th = W_net / Q_in.
5. Mutemo wekutanga weThermodynamics: shanduko musimba muhurongwa dzine chekuita nekupisa nebasa. Muchikamu chakavharwa chakanaka, basa remagetsi rakaenzana nemusiyano uripo pakati pekupisa nekupisa.
Mukuita, kushanda zvakanaka kwemagetsi kunogara kwakaderera pane kwakakodzera nekuda kwekukweshana, kutamiswa kwekupisa kumadziro esirinda, kupisa kusina kukwana, kurasikirwa nekupomba, pamwe chete negasi rinobuda mumhepo uye zvinhu zvinotonhodza.
Kutenderera Kwakanaka Kweinjini yePeturu: Otto Cycle
Injini yepeturu yakakodzera inomiririrwa neOtto cycle, tichifunga kuti kuwedzera kupisa kunoitika nehukuru husingachinji. Matanho makuru eOtto cycle yakakodzera ndeaya:
1. Kudzvanywa kweIsentropic: musanganiswa wemhepo nemafuta unodzvanywa pasina kutamiswa kwekupisa (zvakanaka).
2. Kuwedzera kupisa kwehuwandu hunogara huripo: kupisa kunofungidzirwa kuti kunoitika nekukurumidza kuitira kuti huwandu hurambe hwakafanana.
3. Kuwedzerwa kweIsentropic: gasi rinopisa rinokura, richisunda piston uye richigadzira basa.
4. Kurambwa kwekupisa nguva dzose: kupisa kunorambwa uye kutenderera kunodzokera pakwakatangira.
Kushanda zvakanaka kweOtto cycle kunogona kunyorwa sekushanda kwechiyero chekumanikidzwa:
\[
\eta_{Otto} = 1 – \frac{1}{r^{\gamma – 1}}
\]
apo γ ndiyo chaiyo yekupisa (Cp/Cv). Iyi equation inoratidza kuti kuwedzera chiyero chekumanikidzwa kunowedzera kushanda zvakanaka. Zvisinei, mainjini epeturu anoganhurirwa nekugogodza (detonation), inova moto usingadzoreki nekuda kwekupisa kwakanyanya uye kumanikidzwa kunoita kuti mumwe musanganiswa ubate moto usati wagadzira spark plug yakasimba. Nokudaro, chiyero chekumanikidzwa kwemainjini epeturu chinowanzova chakaderera pane cheinjini dzedhiziri.
Kutenderera Kweinjini Yedhiziri Kwakakodzera: Kutenderera Kwedhiziri
Injini yedhiziri yakakodzera inomiririrwa neDiesel cycle, musiyano mukuru uri wekuti kuwedzera kupisa kunofungidzirwa kuti kunoitika pakumanikidzwa kwakafanana (kana kuti pedyo nekusachinja) nekuda kwekuiswa kwemafuta panguva yekutanga kwekuwedzera. Matanho eDiesel cycle yakakodzera ndeaya:
1. Kudzvanywa kweIsentropic: mhepo yega inodzvanywa kusvika pakupisa kwakanyanya.
2. Kuwedzera kupisa kwemhepo nguva dzose: mafuta anopinzwa uye anopiswa, zvichiita kuti mhepo irambe ichipisa nguva dzose panguva imwe chete.
3. Kuwedzerwa kweIsentropic: gasi rinopisa rinokura uye rinoburitsa basa.
4. Kupisa kwehuwandu hunogara huripo: kupisa kunorambwa kuti kudzokere pamamiriro ekutanga.
Kushanda zvakanaka kweDiesel cycle inoenderana necompression ratio uye cut-off ratio (ρ), inova ratio ye extension volume yekupedzisira kune heat-addition volume yekutanga. Kazhinji, kune compression ratio imwechete, Otto efficiency inowanzo kuve yakakwira kupfuura yeDiesel ideal. Zvisinei, chokwadi chakasiyana: mainjini edizili anowanzo shanda zvakanaka nekuti anogona kushandisa compression ratios yakakwira uye kushanda nekurasikirwa kudiki kwe throttling.
Kuenzanisa kweThermodynamic: Sei Dhiziri Richishanda Zvakanyanya?
Kubva pakuona kwe thermodynamics inoshandiswa, kune zvikonzero zvakawanda zvinonzwisisika:
1. Chiyero chekumanikidzwa kwepamusoro mudhiziri
Injini dzedhiziri dzinodzvanya mhepo chete, saka kugogodza hakusi muganhu wakakura sezvinoita injini dzepeturu. Kumanikidzwa kwedhiziri kunogona kunge kwakakwira zvikuru, zvichikonzera tembiricha yakakwira yekupera kwekudzvanya, kutsva kuri nyore, uye kushanda zvakanaka kwakawedzerwa.
2. Kushanda pasina throttle kana mutoro wakaderera
Injini zhinji dzepeturu dzinodzora simba ne throttle inodzora kufamba kwemhepo. Izvi zvinokonzera kurasikirwa nekupomba, kunyanya kana paine zvinhu zvishoma. Injini dzedhiziri dzinowanzo dzora simba nehuwandu hwemafuta anopinzwa, ukuwo dzichichengetedza mweya wakawandisa, zvichikonzera kurasikirwa kwakaderera kwekupomba uye kushanda zvakanaka kwechikamu.
3. Hunhu hwekutsva uye chiyero chemhepo-mafuta
Injini dzedhiziri dzinowanzo shanda nemusanganiswa usina mafuta akawanda, zvichiita kuti tembiricha dziderere pasi pemamiriro ezvinhu akati wandei, zvichideredza kurasikirwa nekupisa. Zvisinei, dhiziri rinewo matambudziko netwunhu twudiki (soot) uye NOx utsi hunoda kudzorwa.
4. Kukosha kwemafuta uye huwandu hwesimba remafuta
Mafuta edhiziri ane simba rakawanda kupfuura peturu. Kunyange hazvo kushanda zvakanaka kwemafuta kuchiramba kuri pfungwa yakasiyana, izvi zvinokanganisa kushandiswa kwemafuta pakiromita nerita, zvichiwanzoita kuti dhiziri riite serinoshanda zvakanaka.
Zvinhu Zvechokwadi Zvinoita Muitiro: Kubva Pakutenderera Kwakanaka Kusvika Pakutenderera Chaiko
Mavhiri eOtto neDiesel akakodzera anosanganisira maitiro eisentropic uye kuwedzera kupisa "kwakanaka". Mainjini epasi rese anosangana nekusiyana kukuru, kusanganisira:
– Kutamisirwa kwekupisa kumadziro esirinda kunoderedza tembiricha yegesi inoshanda kuitira kuti basa rekuwedzera rideredzwe.
- Kukweshana kwemuchina pamaringi episton, mabheringi, uye zvikamu zvevharuvhu zvinoderedza simba rinoshanda.
– Nguva yekubvira: kutsva hakuitiki ipapo ipapo. Muinjini dzepeturu, kutsva kunoda madhigirii akati wandei ekona yecrankshaft; muinjini dzedhiziri, kune kunonoka kwekubatidza uye kupararira kwekubatidza.
– Gasi rakasara kubva kutenderera rapfuura rinoshandura chimiro netembiricha yemusanganiswa unotevera.
- Kushanda zvakanaka kwevhorumu kunokonzerwa nekugadzirwa kwemuchina wekupinza/kuburitsa utsi uye nguva yevharuvhu, zvichiratidza huwandu hwemhepo inopinda, nokudaro zvichikanganisa simba uye mashandisirwo ayo.
Mukuongorora kweinjiniya, mashandiro anowanzo kuyerwa ne "indexed mean effective pressure" (IMEP) uye "brake mean effective pressure" (BMEP). IMEP inoratidza basa re "thermodynamic" rinoitwa mu cylinder, nepo BMEP iri iro basa rinowanikwa pa shaft mushure mekubvisa kurasikirwa kwemakanika. Musiyano uripo pakati pezviviri izvi une chekuita nekushanda zvakanaka kwemakanika.
Mhedzisiro yeThermodynamic paEmissions
Kudzidza nezve thermodynamics hakugone kuparadzaniswa nekuumbwa kwezvinobuda nekuti tembiricha, kumanikidzwa, uye kuumbwa kwemusanganiswa ndizvo zvinosarudza maitiro emakemikari.
– Injini dzepeturu dzinowanzo gadzira CO neHC kana kupisa kusina kukwana, asi ma catalyst ane nzira nhatu anoshanda kana musanganiswa wacho uri pedyo ne stoichiometric.
– Injini dzedhiziri dzinowanzo gadzira NOx (nekuda kwekupisa kwakanyanya uye oxygen yakawandisa) uye tunhu/soot (nekuda kwenzvimbo dzakapfuma dzemuno mukupisa kwakapararira). Maitiro akadai seEGR (exhaust gas recirculation), turbocharging, uye aftertreatment (SCR/DPF) anoshandiswa kuyera kushanda zvakanaka uye kuburitsa mweya.
Kufambira Mberi Kwemazuva Ano: Turbocharging, Direct Injection, uye Mixed Cycle
Kufambira mberi kwetekinoroji kuri kukanganisa miganho iri pakati pe "hunhu hwepeturu" ne "hunhu hwedhiziri." Injini dzepeturu dzemazuva ano dzinowanzo shandisa injection yakananga uye turbocharging kuti dzivandudze kushanda zvakanaka uye kuderedza kushandiswa kwemafuta, kunyange izvi zvichigona kuwedzera zvinhu zvidiki uye kuda mafirita. Panguva imwecheteyo, mainjini edhiziri emazuva ano anoshandisa multi-stage injection control uye variable turbocharging kuti awedzere kupisa.
Muzvidzidzo zvethermodynamic, mainjini emazuva ano anowanzo ongororwa se dual cycle: kuwedzera kupisa kunoitika zvishoma nezvishoma pahuwandu husingachinji uye zvishoma nezvishoma padanho risingachinji. Iyi modhi inonyanya kushanda pakutsanangura kupisa chaiko kusingazadzise zvizere fungidziro dzeOtto kana Diesel.
Mhedziso
Zvidzidzo zveThermodynamic zvemainjini edhiziri nepeturu zvinoratidza kuti nzira dzakasiyana dzekupisa nekuumba musanganiswa dzinoguma nematanho akasiyana-siyana: Otto (huwandu hunogara huripo) yepeturu uye Diesel (huwandu hunogara huripo) yedhiziri. Kunyange zvazvo Otto cycle yakakodzera ichigona kushanda zviri nani pane chiyero chimwe chete chekumanikidza, mainjini edhiziri ari kushanda anowanzobudirira mukushanda zvakanaka nekuda kwekugona kwawo kushandisa huwandu hwakakwira hwekumanikidza uye kuderedza kurasikirwa kwekupomba pamitoro isina kukwana. Zvisinei, kushanda zvakanaka hakusi nyaya yega: kuburitsa mweya, hunhu hwe torque, mari yesystem, uye zvinodiwa zvekuchengetedza zvese zvinhu zvinosarudza mashandisirwo. Nematekinoroji emazuva ano akadai se direct injection, turbocharging, EGR, uye aftertreatment, mhando dzese dzeinjini dzinoramba dzichifambira mberi kuenda kunzvimbo itsva dzakanaka - kuvandudza kushanda zvakanaka kwekupisa ukuwo dzichideredza kuburitsa mweya - saka kunzwisisa thermodynamics kunoramba kuri hwaro hwakakosha hwekugadzira nekuongorora mashandiro emainjini ekupisa mukati.
