EXPERIMENTAL STUDY OF THE EFFECTS OF AIR-INJECTION, INJECTION TIMING AND COOLED EGR ON THE COMBUSTION, EMISSIONS AND PERFORMANCE OF A NATURE ASPIRATED DIRECT INJECTION DIESEL ENGINE

In this literature, a combined method has been employed to simultaneously reduce smoke (Soot) and oxide of nitrogen (Nox) and maintain the performance parameters of diesel engine. This includes creating an air jet by designing an air-cell inside the piston body, advanced injection timing and using cold exhaust gas recirculation. The tested engine was an M 4.244 engine that worked as natural aspiration. The air-cell causes reduction in both Soot and NOx emissions. Furthermore, applying cold EGR had a noticeable effect on NOx emission reduction. Advancing injection timing, the performance parameters of the engine could be improved. The tests were done in 25%, 50%, 75% and 100% load conditions, for the engine speed of 2000 rpm. The results showed that by simultaneous reduction of Soot and NOx emissions, performance parameters can be kept in a suitable range. The greatest reductions in NOx and Soot emissions have been observed in 100% load. There have been no considerable changes in BSFC (Brake Specific Fuel Consumption and power) while injection timing advances have been applied for 5° CA and 5% EGR.