Modelling of Electrically-Assisted Turbocharger Compressor Performance

Abstract

For the purposes of design of a turbocharger centrifugal compressor, a one-dimensional modelling method has been developed and applied specifically to electrically-assisted turbochargers (EAT). For this purpose, a mix of authoritative loss models was applied to determine the compressor losses. Furthermore, an engine equipped with an electrically-assisted turbocharger was modelled using commercial engine simulation software (GT-Power) to assess the performance of the engine equipped with the designed compressor. A commercial 1.5L gasoline, in-line, 3- cylinder engine was selected to be modelled. In addition, the simulations have been performed for an engine speed range of between1000 and 5000 rpm. The design target was an electric turbocharger compressor that could meet the boosting requirements of the engine with noticeable improvement in transient response. The results from the simulations indicated that the EAT improved the overall performance of the engine compared to the equivalent conventional turbocharged engine model. Moreover, the electrically-assisted turbochargers (EAT) equipped engine with power outputs of 1kW and 5kW EAT was increased by an average of 5.96% and 15.4%, respectively, ranging from 1000 rpm to 3000 rpm engine speed. For the EAT model of 1kW and 5kW, the overall net reduction of the BSFC was 0.53% and 1.45%, respectively from the initial baseline engine model.