Semi-automatic Design Assistance System for Vehicle Future Powertrains

"The current situation in accelerated research and development of environmentally friendly powertrains for future mobility needs calls for compromising mix of well-proven best practices of prime movers, based on renewable energy resources, and implementation of electric components, realizing energy recuperation and harvesting and increasing vehicle flexibility. In-time decision for best concept of a vehicle has to be based on societal needs, regulation requirements and customer acceptance combined with technologically realizable concepts. While the technology options are investigated during well known V-shape process, the other factors create a “roof“ above it, adding A-shape process over V-one. The A-shape process features the upper root with general society demands, followed by more specific constraints for future concepts of vehicles on left-hand branch, addressing environmental impacts, safety&security, total cost of ownership, etc. On the right-hand side, it adds the market and public reactions to a new product. The initial decision on vehicle concept has to be done at early stage of development, which is possible if model-based process is front-loaded at both levels of V and A. The paper describes the principles and practical elaboration of the DASY – Design Assistance System, consisting of two combined aids: OntoDASY offering qualitative hints in Wiki-like information system and DASY, focused on linking currently available software sources and in-house generated database of/for design solutions. The parametric model of a vehicle powertrain consists of different types of engines, gearboxes and electric machines including paradigms for design solution examples. E.g., the current databases contain more than 300 engines with all main components of different concepts in parametrized form. The databases are automatically extended if new design output is finished. The data from engine and component dimension databases are used to fix the overall powertrain concept, its layout and to elaborate it into the component designs, already with specific dimensional parameters. The 3D models of the vehicle powertrain concepts are created in the 3D CAD program using parametric designing, which yields flexibility for further iterative changes. The components are assembled to the models of powertrain mechanisms including tools to determine loads of all components combining 1D thermo/aerodynamics with 3D FEM stress and temperature simulations. Each component of the 3D powertrain model contains material properties, boundary conditions for loads, and finite element mesh to quickly check safety factors in operation and to optimize component shapes by iterative process. The choice of the best concept for detailed elaboration is based on the comparison of previously optimized cases, which enhances the probability of correct decision. The system avoids “invention of invented” losses, conserves the experience collected in the past (important due to design and research staff fluctuation) and supports holistic view on all product development stages. It accelerates the pre-design phase of new powertrains significantly. "