Exhaust Noise Development Based on System Models 2022-01-0622

With the electrification trend in the automotive industry, a virtual and efficient development for exhaust noise performance of ICE (Internal Combustion Engine) vehicle has been demanding. To cope with this challenges, the test-data-driven MBSE (model based system engineering) has been emphasized from its credible correlation with phenomena in vehicle state. In this study, the prediction process for the exhaust noise in vehicle state with the engine and exhaust system models in system state was presented. The system models were built guaranteeing modularity, inherence and description in its operational boundary conditions such as temperature and valve openness of exhaust system. The adequate parameters describing engine source and exhaust system’s acoustic transmissibility were defined and measured experimentally. The analytical equation for coupling system models was derived to predict the exhaust noise at target point and the overall process was implemented with in-house program (ENEP) for building system models and predicting exhaust noise. The credibility of the proposed method was validated in terms of predicted result and system models with measured data and empirical knowledge. The predicted exhaust noise was compared and verified with the measured data in a main combustion order level with 6 cases. It was also verified that the engine source level was proportional to engine’ power and the exhaust system’s transmissibility corresponded with the empirical relation with design parameters such as resonator’s volume and pipe diameter, etc. The NVH developer can assemble engine and exhaust system virtually to predict exhaust noise of the vehicle to be developed at an early stage. From this virtual assembly, the system targets can be set for suppliers and the best system match can be drawn. From this study, the test-data-driven MBSE could be used for a double validation tool with vehicle based development to secure the target quality at an early stage in an efficient way.