Online modelling and control of a turbo charging system using Simulink

Abstract

Combustion system development for future engine applications can be performed on a single cylinder combustion research engine and then with a highly controlled environment. To be able to operate such an engine at relevant conditions comparable to a multi cylinder engine, it is desirable to model and control the boundary conditions, e.g. trough simulation of turbo charging. This work was done as a master thesis during the spring of 2012 at Chalmers University of Technology and the aim was to develop an online simulation of a single turbo system for a single cylinder combustion research engine. The simulation was developed in Matlab/Simulink and integrated in an AVL PUMA test bed system using AVL ARTE.Lab. The turbo performance was predicted by using measured data from the turbo developer, measured according to SAE standard. The model strategy was to predict what charge pressure needed in order for the engine to run at a certain lambda value with a given amount of fuel injected and then calculate whether or not the turbo system would be able to deliver such a charge pressure under the prevailing conditions. The model has been validated both by reference test runs with a real engine as well as comparison with simulations carried out in the software GT-Power. These validations showed that the prediction of charge pressure works well and that the prediction of the turbocharger behavior shows the characteristic of the turbo. Although improvements in this section may be needed for a better accuracy of the prediction as an offset in the values can be seen.