This presentation was made at NAFEMS Americas Seminar "Engineering Analysis & Simulation in the Automotive Industry: Creating the Next Generation Vehicle Accurate Modelling for Tomorrow's Technologies".

The automotive engineering community is now confronting the largest technology transformation since its inception. This includes the electrification of powertrains for more efficient consumption and cleaner emissions, the reinvention of the battery with fast wireless charging capabilities and finally the advent of a fully autonomous vehicle. Compounding to these technology changes, the automotive companies design verification process is moving away from a major reliance on physical testing to almost a full virtual simulation product verification process. The challenges to the automotive engineers are enormous and require a significant increase in the upfront use of numerical simulation capabilities, methods and processes such they’re able to efficiently design, manufacture and deliver these very innovative technologies to the market in greater speeds than ever before.

Resource Abstract

As the automotive OEMs across the world start the development of next generation electric vehicles, they face unique challenges in terms of battery technology, system architecture, operating strategies and NVH. While effective choice of the first three is required to meet the requirements on metrics such as range of the vehicle, thermal management of the battery pack, energy management and lifetime of the battery, the absence of a conventional IC engine poses unique challenge for NVH since the cabin is relatively quieter in case of electric vehicles. System simulation is used both very early in the V-model of the product development for design concept evaluation as well as in the later half of the V-model for HIL and control software testing. As most products are made-up of multi-physical systems, system simulation focuses on interaction of all the subsystems and components of a technical system including the control aspect. This study presents the use of system simulation to evaluate design concepts in the electric vehicle development using the system simulation tool SimulationX. Based on the non-proprietary modeling language Modelica, SimulationX provides a platform dedicated to system simulation for modeling, simulation, analysis and post-processing of multi-physical systems. It comes with pre-built libraries that cover basic physical domains such as mechanics, electrics, magnetics, thermal-fluid etc. as well as dedicated libraries such as power transmission, vehicle drives & controls, electric energy storages etc. to cater specific applications. The presentation highlights the use of SimulationX to build subsystem and system level models and analyze the aspects of energy & thermal management, powertrain NVH and controls. While the energy management presents modeling and analysis to meet metrics such as energy consumption, battery lifecycle (cyclic and cylindrical aging), range, powertrain component sizing, thermal management analysis addresses the areas of battery heating & cooling and HVAC. Similarly, powertrain NVH analysis discusses how to build detailed transmission models to help identify the noise sources, minimize noise emissions, evaluate stresses in the components due to vibrations and perform efficiency studies. In addition, a framework to couple system simulation model with FEM based vibroacoustic model for interior cabin noise predictions will be discussed. Finally, the use of system simulation to arrive at control strategies for operating mode, transmission gearshift, battery thermal management system will be presented.