Environmental pollution by diesel engines. Part II: A literature review regarding HC, CO, CO2 and soot emissions

Autor/autori: Oana ZBARCEA, Dan SCARPETE, Vlad VRABIE

Rezumat: Motoarele cu aprindere prin comprimare (CI) genereaza emisii nedorite in timpul procesului de ardere, iar principalele emisii poluante sunt hidrocarburile (HC), oxizii de azot (NOx), particulele materiale (PM), fumul negru, monoxidul de carbon (CO) si dioxidul de carbon (CO2). Acesta lucrare doreste să treaca in revista unele date din literatura de specialitate despre emisiile de HC, CO, CO2 si formarea funinginei in motoarele diesel, pentru a avea o perspectiva mai clara privind efectul emisiilor asupra mediului inconjurator. Motoarele diesel ofera posibilitatea combinarii randamentului termic foarte ridicat cu un nivel foarte scazut al emisiilor, iar consumul lor redus de combustibil determina un nivel redus al emisiilor de CO2. Temperaturile foarte ridicate din camera de ardere, ajută la reducerea emisiilor de funingine, dar produc emisii ridicate de NOx. Testele pe standul cu role au scos in evidenta faptul ca emisiile de HC pentru un autoturism diesel si un camion au atins minimul la viteza de 50km/h. Emisiile de HC depind de sarcina motorului, cu cat sarcina este mai mare, cu atat nivelul emisiilor de HC vor fi mai mic.

Cuvinte cheie: motoare diesel, emisii poluante de HC, CO, CO2, funingine, mediu inconjurator.

Abstract: Compression ignition engines (CI) engines generate undesirable emissions during the combustion process, and the main pollutants produced from the exhaust of IC engines are hydrocarbon (HC), nitrogen oxides (NOx), particulate matter (PM), black smoke, carbon monoxide (CO), and carbon dioxide (CO2). This paper aims to review some literature data about HC, CO, CO2 emissions, and soot formation from diesel engines, for having a more clear perspective on the main exhaust harmful for the environment. Diesel engines offer the possibility of combining very high thermal efficiencies with very low emissions, and their good fuel efficiency results in low CO2 emissions. Very high temperatures in the combustion chamber help reduce the emission of soot but produce higher levels of NOx emission. Driving tests on chassis dynamometer shoved that HC emissions for a diesel passenger car and a truck have reached a minimum at a vehicle speed of 50 km/h. HC emissions depend on diesel engine load, the higher load, the lower level of HC emissions.

Keywords: diesel engines, emissions of HC, CO, CO2 and soot, environment.

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