New Approach for Road Induced Noise Prediction in Battery Electric Vehicles 2023-01-1069

Most of the Automotive companies are using Simulation tools for predicting road noise in digital phase as a regular practice. But we can predict Road noise at early design stage itself by this hybrid tool in very quick time. In-cab booming noise is low frequency (20 Hz∼300 Hz) phenomenon excites the cabin structure, which occurs mainly due to excitations from the powertrain, exhaust system, road input, etc. When a vehicle drives over road seams or a bumpy surface, low-frequency noise called drumming is generated, causing driver discomfort. The generation of drumming noise is due to road irregularities, transferred and amplified through the vibration characteristics of the suspension, body frame, and body panels, as well as the acoustic characteristics of the vehicle interior. It is therefore difficult to take measures to get rid of drumming after the basic vehicle construction has been finalized. The regular practice is Finite Element Method (FEM) to obtain acoustical transfer functions of the body, and Multi Body Simulation to get suspension load characteristics. The full vehicle simulation needs more time for analysis and extracting data. Agile methodology changes are not sequential. So regular CAE analysis will not support development timeline. Market has become very dynamic, Benchmark changes very often, So getting complete data is difficult for very accurate analysis. A new user-friendly hybrid tool is developed for predicting and improving road noise at early stage with limited data. The Inputs used are Vibration data of benchmark vehicle at body attachment points from testing, Current targets values or simulation data of DPDS, NTF, etc. By doing this overall trend of road noise can be predicted, Critical paths can be identified by transfer path analysis. Product development timelines has crunched. Once as program matures, we can use physical test data of DPDS & NTF of the trimmed body and perform the root cause analysis to identify the critical paths. But there are some limitations such as benchmark testing data availability, Trimmed body level Simulation data, etc. Based upon the analysis, modifications to be made on actual body structure for effective drumming reduction. Hence new hybrid approach proposed which consists of mathematical model and design philosophy for better in cabin noise.