A new approach for optimum selection of a turbocharger using a genetic algorithm

A new method of selecting an optimum turbocharger for a specific engine using thermodynamic and turbomachinery analyses is presented in this paper. The optimum turbocharger was selected for enhancing the power output of the engine by minimizing an objective function (the sum of the compressor losses and the turbine losses). Constraints in the optimization process were used to locate the operating points of the turbocharged engine at the appropriate position on the compressor map (with a sufficiently large distance from the surge line and the choke line) as well as to satisfy a few parameter values. The design parameters in the optimization procedure were the geometric and aerodynamic parameters of the compressor and the turbine. The proposed method was used to specify the geometry of an optimum turbocharger for an engine (the OM 457 LA diesel engine in our case study) or to select a turbocharger from the vendor list. On applying the above procedure for selecting a turbocharger, the compressor efficiency of the selected turbocharger at various engine speeds was between 0.67 and 0.76, the turbine efficiency was between 0.68 and 0.74, and the index for the appropriate distance from the surge line and the choke line on the compressor map was between 0.2 and 0.72.