Experimental Investigation of EGR temperature effect on bsfc and effectiveness of an IDI diesel engine

IDI diesel engines are well established today as the main power train solution for trucks and other relevant heavy duty vehicles. At the same time emission legislation (mainly for NOx and particulate matter) becomes stricter, reducing their limit to extremely low values. Exhaust gas recirculation (EGR) is effective to reduce nitrogen oxides (NOx) from Diesel engines. But the use of high EGR rates creates the need for EGR gas cooling in order to minimize its negative impact on bsfc (brake specific fuel consumption) and effectiveness especially at high engine load were the EGR flow rate and exhaust temperature are high. In this study was designed a heat exchanger to cooling exhaust gas and was carried out an experiment to investigate the effect of Exhaust Gas Recirculation (EGR) temperature on bsfc and effectiveness of an IDI diesel engine cylinder. To serve this aim an exergy analysis is conducted on the engine cylinder which provides all the availability terms by which the evaluation of in-cylinder irreversibilities is possible. To clarify the effect of using EGR in each case, EGR is introduced to the cylinder at various ratios and temperature during the tests. The results show that using EGR mostly increases bsfc of diesel engine. Also the results reveal that the decrease of EGR gas temperature at full load has a positive effect on effectiveness.

کلیدواژه ها:

diesel engine ، Exhaust Gas Recirculation ، effect temperature