Abstract
Exhaust gas recirculation (EGR) is known as an effective measure to reduce NOx emission. In order to do that, a system which allows a part of exhaust gases recirculate to intake manifold and then combustion chamber. By this way, the combustion temperature reduces which help NOx emission formation decrease.
In this paper, the simulation of exhaust gas recirculation retrofitted for a turbocharged diesel engine buses was made on AVL-Boost using AVL MCC combustion model. In order to recirculate the exhaust to the intake manifold after the compressor, a venturi was designed to reduce boost pressure to lower than that of the exhaust. Input parameters for the simulation model were obtained from performance tests conducted on high dynamic engine test-bed for the D1146TIS diesel turbocharged engine at Key Laboratory of Internal Combustion Engine, Institute of Transportation Engineering, Hanoi University of Technology.
Findings of the research show the optimum EGR rates at different speed and load curves of the engine, the NOx reduction potentials comparing with that of the original engine, and the potentials of soot concentration increases due to less oxygen for the combustion. At 2200 rpm, 80% load, and with 8,9% EGR rate, the NOx emission was reduced to 7 g/kW.h (Euro2 emission limits), which is 29.5% reduction compared to that of the original engine. However the soot emission was increased 138%, and the power and fuel consumption were deteriorated 0.63% and 0.64%, respectively.
Keywords: NOx reduction, EGR, turbocharged diesel engine