Heavy Duty Diesel Engine and EAS Modelling and Validation for a Hardware-in-the-Loop Simulation System

Faced with the need to reduce development time and cost in view of additional system complexity driven by ever more stringent emission regulations, the Hardware-in-the-Loop (HiL) simulation increasingly proves itself to be an advantageous tool not only in automotive companies but also in the off-road engine industry. The approach offers the possibility to analyze new engine control systems with fewer expensive engine dynamometer experiments and test drives. Thus, development cycles can be shortened and development costs reduced. This paper presents the development of an Internal Combustion Engine (ICE) and the correspondent Exhaust Aftertreatment System (EAS) model, its deployment on a HiL system and its application to pre-calibrate the engine for different vehicle cycles. A zero-dimensional mean value approach was chosen to guarantee adequate real-time factors for the coupling between the models and the Engine Control Unit (ECU). The main components of the airpath were parametrized according to data provided by the supplier and measurements. The combustion and NOx Engine-Out emissions were modeled using AVL-CRUISEMTM/MoBEOTM libraries, combining physical and empirical approaches, to reach an optimal trade-off between computational cost, accuracy, predictivity. For the other emission constituent, empirical correlations were obtained, and fed with simulated inputs to improve the accuracy in transient cycles. The quasi-dimensional aftertreatment model was parametrized using both synthesis gas test-bench and engine test bed measurements. The results for engine performance and emissions produced satisfactory agreement with both steady-state and transient measurements. Therefore, the presented methodology shows a great potential for testing and validation of new engine calibrations, as analyzed in a reference cycle described in detail. Besides, the use of this simulation method gives the opportunity to verify and optimize the behavior of the propulsion and exhaust aftertreatment systems in different operating conditions and in different engine applications as well, allowing to transfer a significant part of the calibration and testing work for emission calibration to the cost effective HiL environment.