Noana wadau hapo juu wavutana kuhusu thermostat,
But kiufupi Thermostat ni muhimu kwenye gari for proper temperature control..jua ukitoa thermostat injini inachelewa ku attain its operating temperature quickly, hivo inapelekea gari kuanza ku develop matatizo madigo madogo pindi inapoendeshwa before engine haijafika kwenye operating temperature.
Thermostat hufanya kazi ya kuzuia maji ya moto yasi escape kutoka kwenye engine kwenda kwenye radiator bila kuruhusiwa for heat exchange..sasa hii maana yake nikwamba thermostat inawekwa ku enhance rapid temperature increase kwenye combustion chamber ili kufanya piston na piston rings ziweze ku expand (kutanuka pindi joto linapanda) na kuyeyusha oil, lakini pia kiupandisha oil ndani ya muda mfupi kwenye piston sleeves ( cylinder bore) na kwenye cam shafts, and at the same time silencer (idle speed huwa juu kama ndo wa iwasha injini) hii mechanism ndo hutokea ili injini uweze sasa kufanya kazi inavotakiwa ambapo utakuta piston zimetight vizuri kwenye bore na compression inakua poa hivo injini haiitaji mafuta mengi tena kufanya kazi (kama umegundua injini ikiwa ya baridi ukiwasha unasikia hadi harufu ya mafuta nabichi kwakua combustion haiwi complete wakati wa baridi na oxygen sensor inakua haipati feedback nzuri wakati wa injini ikiwa ya baridi, na ndo maana some models utakuta oxygen sensor ina heater kwa ajili ya hili jambo)
sasa gari ikisha attain temperature inayotakiwa, thermostat inakua inafanya kazi ya kufunguka kuruhusu maji ya moto kutoka na maji ya baridi kuingia ili ku maintain temperature.. namna hii kitu inafanya kazi kunakua na coordination kati ya thermostat, fan switch, na mfuniko wa radiator.. ambapo kwakua mfumo wa upozaji wa injini ni closed system, what happens Temperature inakua controlled by means of pressure inayokua generated na maji pale yanapokua yamekua ya moto na kutaka kuchange form kutoka liquid form to steam(mvuke). Tambua ili maji yawe na uwezo wa ku-transfer heat muda wote yanatikiwa kuwa kwenye liquidi form not otherwise..sasa thermostat pamoja na mfuniko wa radiator huakikisha maji yanakua kwenye kiminikia muda wote..sasa kadiri joto la maji linavozidi kupanda, pressure ya maji hupanda sana kufikia hatua Ile pressure husukuma spring ya thermostat na kuruhusu yale maji ya moto yenye pressure kutoka, yakisha na wakati huohuo yale maji yamoto yanapotoka hukutana na switch ya fen nakuwasha fen ya radiator, nakama switch yako inafanya kazi kwa kuchange resistance basi fen speed ita respond accordingly kulingana na signals za resistance ya joto rid la maji...basi pia ile pressure ya mji itahamia kwenye mfuniko wa radiator ambapo pia ule mfuniko ni spring loaded, sasa kwakua ni spring loaded, nao uta expand na kuruhusu ile excessive pressure kutoka kwenye mfumo wa cooling system na kuhamia kwenys reserve tank ya radiator.. ambapo kwenye reserve tank pressure will be released to surrounds na cooling cycle itakua imekamilika na process itaanza..sass ikitokea thermostat inashindwa funguka basi pressure kwenye system itakua kubwa na itapasua pipe na gari ita over heat na water will be turned to steam...pia hata radiator cap isipofunguka wakati wa pressure inapojaa inaweza sababisha pipe kupasuka pia au kama umeweka radiator cap yenye spring ngumu nayo inaleta shida kwenye cooling system (ndo maana kila cooling system ipo na specific radiator cap with recommended spring weigh ie 1.1kg or, 0.9kg...etc..
Lakini pia kumbuka injini ikipoa huwa ina sinyaa na cooling system husinyaa hivo kutengeneza vacuum kwenye cooling system, sasa vacuum huweze ku introduce air ndan ya cooling system na cooling system haitaji hewa,so ku avoid hii kitu utakuta mfuniko wa radiator una kidude kama kichuchu, kazi ya hiki kidude hurusu vacuum ya cooling system iweze kunyonya maji kutoka kwenye reserve tank na kuzuia succussion ya hewa..na kama hiki kichuchu kisipo funguka utakuta pipe za cooling system zina sinyaa pale injini inapoa.
Sasa here are issues when running engine without thermostat.
1.unaweza leta shida ya piston slap..yaan piston kuwa zinachapa cylinder walls..hii inakua hivi.. injini inapokua imepoa piston huwa zinakua kama zinapwaya kwenye cylinder bore, but injini ikisha kua ya moto piston hutanika na kufikia size inayozkaiwa..sasa the more the time is taken for an internal combustion engine to reach its optimal operating temperature the more the time piston slap will be happening, na hali huwa mbaya zaidi kama gari unawasha na kuondoka with rpm more than 1.5rpm. (utajuaje kama gari ina piston slap..unasikia mlio fulan kakakakakaka alafu baadae injini ikisha pata joto mlio unapotea au kupungua inategemea na tatizo lipo stage gani (mlio unakua kama knocking sound but unatokea juu ya injini na si chini ya injini) kumbuka damage ya piston slap ukichelewa inakulazimu hubarishe block ya injini kwakua piston slap huwa inachimba cylinder wall na inakua piston yenyewe kwa chini ni kwa juu in the opposite side.
2. Running a car with no thermostat unafanya muda wote maji yawe yanazunguka hakuna muda maji yanasimama ili kupoa, so under extreme conditions with limited airflow mfano kwenye milima mikali na mirefu inaweza tokea maji yote yakawa na same temperature hivo cooling ikiwa isiwe effective.
3. Pia kuna mazingira thermostat isipokuwepo injini hupoa sana below the required temperature, hii nayo ni shida na hufanya gari kula mafuta mengi na hata kula oil kuwakua oil ikisha tembea sana husinyaa na kua nyepesi lakini wakati huo huo piston zinapopungua joto hu contract na kuacha space inayoweza ruhusu oil ikavuka piston rings na kuingia ndani ya combustion chamber, na compression huwa ndogo kwakua piston hazijai ndan ya sleeves/bore so ili kukupa power unayotaka, engine has to burn more fuel ku compensate power losses due to low compression inayotokana na thin pistons na thin piston rings.
4. Carbon formation
Mambo ya kuzingatia kuhusu overheating.
Kumbuka kinacho haribu thermostat mara nyingi ni maji tunayotumia (twatumia maji na sio coolant.maji hutengeneze kutu na kufanya thermostat ing'ang'anie.
Na pia unapoenda kununua coolant usinunue anti freezing...huku sio nchi ya baridi so hatuhitaji anti freezing, bali tuna hitaji coolant yenye higher boiling point more than 100°c ili ku raise boiling point ya cooling system.
Una flush cooling system au inapotokea kwa namna moja au nyingine maji yote yamatoka kwenye cooling system na unakata rudishia Maji, hakikisha hewa yote imeondoka kwenye cooling system, ukoacha hewa pockets unatenngeza gaps za coolant ku flow na kusabibisha un even cooling ndani ya injini, pia unasabisha maji yachemke to steam na kupunguza uwezo wa maji kupoza injini na kuleta overheating.
Hakikisha radiator fen yako inazunguka upande ulio sahihi..yaan ina peleka upepo kwenda kwenye engine (either pull or push but towards engine side) kutegemea na feni ipo mbele ya radiator (push) au nyuma ya radiator (pull)
Hakikisha radiator yako haina blockage zozote zinazo zuia maji kupita kwenye zote za radiator core..ikitoea kuna blockage, basi surface area for cooling itapungua significantly na kupunguza cooling efficient, hence overheating.
Kuna overheating zinazo sababishwa na blown head gasket or cracked cylinder walls kwa kesi kama hii inakulazimu ufungue engine u change head gasket ua utatue tatizo la cylinder iliyo crack ndo cooling system itakaa poa.
Overheating issues inaweza tokea kama water pump ina vuja, au impeller imekufa ndani.
Overheating can be caused just by improper radiator cap.. radiator can can cause overheating na severe engine damages..hakikisha unazingatia ratings za mfuniko wa radiator na si kuchukua mfuniko tu ili mradi ni mfuniko unaweka kwa gari yako..be careful kila cooling system ipo na pressure rating yake so na mfuniko unatakiwa uwe sawa na rating ya system yako ili pressure inapojaa mfuniko ufungue valve kwa wakati kuruhusu pressure kua released na ku avoid bursting of pipes na overheating.