Regulated Two-Stage Turbocharging for gasoline Engines - Matching, Control Strategy and Operating Behavior

摘要

The use of one-stage turbocharging with gasoline engines requires compromises between steady-state and the transient behaviour. The demand for a further spread in the torque range with a simultaneous excellent dynamic response increasingly leads to a discussion, demanding that regulated two-stage turbocharging used with Diesel engines be used with gasoline engines as well. In this article, a system of this type for gasoline engines with its specific properties is presented. The demands with the use of gasoline engines show that careful design of the individual components is necessary in order to generate a high-performance overall system. A detailed analysis of the influence of the compressor and turbine design for improvement of the steady-state and the transient behaviour will follow. In this context, the optimization of compressors for two-stage operation is discussed. Furthermore, the operating behaviour when used in extreme conditions, particularly at high-altitude, is examined. A turbocharging system optimized in this way significantly exceeds the performance data of one-stage turbocharging and means significant progress on the way to better fuel efficiency together with higher-performance gasoline engines.