Effect of Exhaust Gas Recirculation (EGR) on the Performance Characteristics of a Direct Injection Multi Cylinders Diesel Engine


Owing to the energy crisis and pollution problems of today investigations have concentrated on decreasing fuel consumption and on lowering the concentration of toxic components in combustion products by using exhaust gas after treatments methods like PM filters and EGR for NOx reduction. In this study, the combustion characteristics of diesel fuel were compared with that produced from adding EGR at several percentages to air manifold. The tests were performed in a four-cylinder direct injection (DI) diesel engine at constant engine speed (1500 rpm) and variable loads (from no load to 86 kN/m2), the tests were repeated with constant load (77 kN/m2) and variable engine speeds (from 1250 to 3000 rpm).The experimental results showed that adding EGR to diesel engine provided significant reductions in brake power (bp), brake thermal efficiency and exhaust gas temperatures, while high increments in brake specific fuel consumption (bsfc). High EGR percentage (as 30% in this article) caused an 11.7% reduction in brake thermal efficiency, 26.38% reduction in exhaust gas temperatures and 12.28% in volumetric efficiency at full load conditions.