Steady-state emulation of a diesel engine air charging system through real-time turbocharger modelling

Abstract

Engine downsizing is an important route to meeting tightening emission regulations and improving engine efficiency. However, when a new air charging system such as a turbocharger is selected to enable downsizing of an internal-combustion engine for increased specific power and efficiency, extensive resource-intensive optimization procedures are currently required. In this paper, a method of emulating an engine charge system is developed on the basis of a charge air-handling unit and a real-time turbocharger model comprising map based compressor and turbine models with improved data density and range via numerical and analytical approaches. Variables such as the boost pressure, back pressure, turbocharger speed and the mass flow rate of air are used to compare the response of the charge system emulation with the real turbocharger. The emulation method achieves considerable accuracy when compared with the real turbocharger hardware. This approach will enable future engine developments to be assessed prior to the prototype hardware phase, resulting in significantly lower costs and shorter time frames for the development process.