Systematic calibration procedure for the air path control of diesel engines

Abstract

Heavy-duty diesel engines are designed for low fuel consumption and flexibility in the engine-out emissions of Nitrogen Oxides (NOx) and Particulate Matter (PM) to meet the Euro VI en EPA13 emission legislation and market expectations on low operating cost. Generally, the amount of NOx formed in the combustion chamber exceeds the legal tailpipe limits. Therefore, a diesel engine can be equipped with a catalyst that converts the NOx to harmless N2 and O2 by the injection of a urea solution. Flexibility in engine-out NOx emissions is required to deal with the varying conversion performance of the catalyst.

It is common knowledge that the formation of NOx during the combustion can be reduced by applying cooled Exhaust Gas Recirculation (EGR). A state-of-the-art diesel engine layout that comprises cooled EGR is depicted in Figure 1. The engine is equipped with an EGR valve and a Variable Geometry Turbine (VGT) that give authority over the EGR mass flow.