Theoretical and experimental study on the performance of a sequentially turbocharged diesel engine

A theoretical and experimental study on sequentially turbocharged diesel engine performance has been carried out on a 6-cylinder medium speed marine diesel engine. The sequential turbocharging system with two turbochargers of unequal size resulted in significant improvement when compared with the original and conventional turbocharging system. The engine low speed performance is improved substantially with a fuel saving up to 7 g/kWh. The engine high speed performance is also improved but the gin is limited. Two control valves, one at the peak unit turbine inlet and the other at its compressor outlet, are specially designed and worked properly during the engine test. A modified "Method of Characteristics" (MOC) approach is applied for simulation of unsteady flow in the exhaust manifold of the sequential turbocharging, ST, system. The pressure wave simulation results are in agreement with the turbocharging test results.