IMPROVED MAP SCALING METHODS FOR SMALL TURBOCHARGER COMPRESSORS

Today engine performance simulations are essential in the preliminary design of turbocharged combustion engines, e.g. when matching the engine and the turbocharger In order to optimize this matching process and to enable a preliminary selection of different turbocharger types and sizes, realistic modifications of the compressor and turbine maps are needed. This paper discusses several published approaches for compressor diameter scaling methods. In this context, an improved method to determine the efficiency changes due to diameter scaling of small turbocharger compressors is presented. Besides diameter scaling, trim scaling is a possibility to change the operating range of a compressor: Therefore, a trim scaling method is provided. In order to validate the scaling methods, scaled compressor maps are compared to measured nominal maps.