Two-Stage Boosting of Spark Ignition Engines

Authors

Dipl.-Ing. S. Schmuck-Soldan, Dipl.-Ing. A. Königstein, Adam Opel AG, Rüsselsheim; Dr.-Ing. F. Westin, General Motors Powertrain - Europe S.r.l., Torino

Year

2011

Print Info

Fortschritt-Berichte VDI, Reihe 12, Nr. 735

Summary

Reduction of fuel consumption without compromising performance or driveability is a central goal of engine development. Downsizing and downspeeding by means of turbocharging has already proven to be a viable solution to this challenge. Applying conventional, single-stage charging systems allow downsizing ratios of 30-40%. But, if more aggressive downsizing is pursued, reduced low-end torque and slower transient response can cause performance and drivability to suffer. This paper describes the application of two-stage turbocharging to extend the downsizing ratio potential to 60%. Successful execution of the concept involves intensive optimization of the high- and low-pressure stages via simulation of both stationary and transient operation. Special design features are proposed to ensure optimal functionality and durability and to minimize heat loss.

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