1D Engine Simulation Approach for Optimizing Engine and Exhaust Aftertreatment Thermal Management for Passenger Car Diesel Engines by Means of Variable Valve Train (VVT) Applications 2018-01-0163

Using a holistic 1D engine simulation approach for the modelling of full-transient engine operation, allows analyzing future engine concepts, including its exhaust gas aftertreatment technology, early in the development process. Thus, this approach enables the investigation of both important fields - the thermodynamic engine process and the aftertreatment system, together with their interaction in a single simulation environment. Regarding the aftertreatment system, the kinetic reaction behavior of state-of-the-art and advanced components, such as Diesel Oxidation Catalysts (DOC) or Selective Catalytic Reduction Soot Filters (SCRF), is being modelled.

Furthermore, the authors present the use of the 1D engine and exhaust gas aftertreatment model on use cases of variable valve train (VVT) applications on passenger car (PC) diesel engines. The VVT applications consider a wide range of variables such as exhaust cam phasing, late intake valve opening, Miller, 2nd exhaust event and cylinder deactivation. The model has been validated with the results of experimental investigations to do this in a first step. Secondly, the VVT applications are implemented to the model to analyze their heating potential according to an efficient engine and exhaust gas thermal management. Various heating strategies have been investigated for a full-size vehicle within extended engine speed and load ranges which are relevant for the Worldwide Harmonized Light Vehicles Test Cycle (WLTC) and even more for the determination of Real Driving Emissions (RDE). The results are compared to a conventional heating measure to demonstrate the potential in terms of a faster aftertreatment light-off with increased conversion efficiencies and benefits in CO₂ emissions. As conclusion out of the investigations it can be seen, that a cylinder deactivation or a second exhaust event could provide up to 5-10% CO₂ reduction under RDE conditions that comply with the EU6d legislation limit.