Özet:

The demand for higher output efficiencies, greater specific power output, increased reliability, and ever reduced emissions has been rising. One promising alternative is the use of a gaseous fuel as partial supplement to liquid fuel. In this study, the effects of diesel-natural gas substitution ratios on the engine performance parameters like brake specific fuel consumption (BSFC), and gaseous emissions of nitrogen oxides (NOX), hydrocarbons (HC), carbon monoxide (CO) and carbon dioxide (CO2) were investigated for natural gas-diesel fuel operation and then compared with the original diesel operation. The engine was modeled with GT-Power computational simulation tool. The diesel fuel was injected into the cylinder while natural gas was injected in to air-intake pipe then compressed together with air. The simulation was carried out at constant engine speed of 1800rpm for four different natural gas fractions (15%, 25%, and 50% and 75%). NOX and CO2 emissions decreased sharply by more than 45% and 50% respectively in dual-fuel mode when compared to only diesel fuel mode. However an increase was observed in CO and HC emissions in dual fuel mode. The results also indicated that higher BSFC and lower brake thermal efficiency (BTE) in dual fuel mode when compared to those of the corresponding diesel engine.

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