Abstract
One of the envisaged strategies to comply with the EURO 4 limits in HD turbocharged diesel engines is the utilisation of EGR. The expected high ratio of re-circulated gas necessary to achieve the important reduction of NOX and the adverse conditions to produce it (intake mean pressure higher than the exhaust value in many operating conditions) has brought a lot of attention to the different alternatives.
The objective of this work is to analyse how the system to produce EGR influences the equilibrium conditions between the engine and the turbocharger and evaluate how they affect the main parameters of the gas exchange process.
Several alternatives to produce the required EGR ratio are theoretically studied with an accurate modelling of the engine and the EGR system by means of a one dimensional gas dynamic model.
The influence of this system on the gas exchange process parameters is then identified. The results provide a preliminary base for the analysis of trends.