THE IMPACT OF THE EXHAUST SYSTEM'S CORROSION ON THE QUALITY OF THE ECO-TEST

U radu je analiziran utjecaj kvalitete ispušnog sustava automobila na rezultate mjerenja ispušnih plinova kod Otto i Diesel motora. Tijekom rada na tehničkom pregledu vozila primjećena je povezanost kvarova na ispušnom sustavu s rezultatima eko testa. U teorijskom dijelu rada su obrađene teme vezane za koroziju u vrućim atmosferama, odnosno u ispušnom sustavu, te opis materijala korištenih za izradu ispušnog sustava i elemenata vezanih za koroziju ispušnog sustava. U eksperimentalnom dijelu je obrađena analiza i usporedba vozila s ispravnim i neispravnim ispušnim sustavom te njihovi rezultati Eko testa. Ispitivanje je odrađeno u Stanici za tehnički pregled Centra za vozila Hrvatske Donji Miholjac tijekom redovnog rada nadzornika tehničke ispravnosti vozila. Svi podaci korišteni u radu su anonimni i služe samo za statističku usporedbu podataka bez identifikacijskih oznaka vozila i vlasnika vozila. Zaključak je bio da oštećenja mogu imati pozitivan i negativan utjecaj na prolaznost Eko testa kod vozila. Kod vozila s Otto motorom, kod kojih se mjeri sastav ispušnih plinova, povećava se udio kisika što rezultira povećanim λ faktorom i padom na Eko testu dok se kod vozila s Diesel motorom može dogoditi da većina plina izađe kroz oštećenja pa mjerena zacrnjenost bude manja, odnosno rezultat Eko testa bolji nego kod ispušnog sustava bez oštećenja.The impact of the exhaust system quality on the exhaust gases testing was analized in this Masters thesis in both Otto and Diesel engines. By working at a vehicle inspection station an observation has been made considering linking exhaust system faults with the result od the exhaust gases testing. The theoretical part of the Master thesis deals with themes considering high temperature corrosion in the exhaust systems and the description of the materials used in manufacturing exhaust systems and parts related to them. The experimental part of the Master thesis deals with analysis and the comparison of vehicles with correct exhausts and the ones with faults in their exhaust systems. The examination was conducted in Croatian Vehicle Center's Vehicle inspection station Donji Miholjac by working as a vehicle inspection supervisor. All data used in the thesis was anonymous and used only for a statistical data comparrison without the vehicle owners data and the vehicles VINs. The conclusion was that the faults in exhaust systems can have both positive and negative impact on vehicle exhaust gases examination. Vehicles with an Otto engine that have faults in their exhaust system have a raised oxygen levels resulting in raised λ factor and failing the examination while vehicles with Diesel engines leak the exhaust gases so the minority of gases go to the exhaust pipes into the examination machine so the examined levels seem better than what they would be in exhaust systems without faults