Methodological analysis of variable geometry turbine technology impact on the performance of highly downsized spark-ignition engines

New generation of spark ignition (SI) engines are expected to represent most the future market share in a context powertrain hybridization. Nevertheless, current technology has still critical challenges front meet incoming CO2 and pollutant emissions standards, so new technologies emerging improve engine efficiency. In parallel combustion concepts, key required trend is downsizing based on high boosting. turbocharger technologies, such as variable geometry turbines (VGT), become suitable for its application under demanding operating conditions SI engines. this work, methodology analysis VGT usage comparison with traditional waste-gate (WG) turbine presented. From experimental data obtained test cell, theoretical aimed at ensuring full control boundary conditions, variability, compressor map or calibration, was conducted. Taking advantage highly validated physically representative 1-D gas-dynamics models, performance discussed function partial load wide range speed same time altitude impact addressed. all, it found that shows less limitations extreme working low- high-end torque regions, where WG represents limitation terms maximum power output. Full differences more even evident conditions. When comes loads, fuel consumption minor, but potentially beneficial VGTs.