Study on the Effect of Turbine Inlet Temperature and Backpressure Conditions on Reduced Turbine Flow Rate Performance Characteristics and Correction Method for Automotive Turbocharger

In actual vehicle operation, the turbocharger turbine operates at various temperatures, inlet, and backpressure conditions, unlike compressors. The flow rate characteristics of the turbine are generally evaluated under certain conditions using an assembled turbocharger with a compressor and a turbine and a hot gas bench from the turbocharger manufacturer. Flow rate characteristics are also presented as the reduced mass flow rate to correct the flow rate characteristics according to the turbine inlet temperature and pressure. Therefore, the turbine mass flow rate seen in many engine development cases and studies—including the analysis of the turbine performance and characteristics, engine model configuration, and matching of the engine and turbocharger—is calculated according to the reduced turbine mass flow rate performance and turbine inlet temperature and pressure obtained through hot gas bench experiments under certain conditions. However, the performance of the reduced turbine mass flow rate is influenced by the compressor power conditions, and additional correction of the reduced turbine mass flow rate is required when the turbine inlet temperature and turbine backpressure differ from the reference test conditions, such as the hot gas bench test conditions. In this study, the effect of the turbine inlet temperature and turbine backpressure on the performance of the reduced turbine mass flow rate were examined based on the power balance relationship between the compressor and turbine of an automotive turbocharger. The principle of its correction is also presented.