Highly flexible hot gas generation system for turbocharger testing

The paper presents the design and prototyping of a gas generator system for turbocharger experimental testing capable of delivering a wide range of flow rates with adequate thermodynamic characteristics. The system feeds the turbocharger test section with an hot gas stream of prescribed mean and time varying pressure and temperature in order to fully span the operating domain of the device with controlled accuracy. Compared with the more conventional gas combustor system, it allows for a safer rig operation ensured by the structural robustness of a four stroke diesel engine and an easier turbine inlet flow control. The latter is achieved by means of an external supercharging station and a modern ICE electronic control unit so that mass flow rate, pressure and temperature values can be set independently. The steady compressor and turbine performance maps can be obtained operating the rig according to a conventional procedure, i.e. collecting a set of flow rate pressure ratio data points (ṁ_g, π) for given hot gas properties. Alternatively using more advanced operating modes unsteady testing is possible to reproduce the complexities characterizing the driving cycles required by the latest European regulations.