Design methods for modern electric and hybrid electric vehicles: concept design and context analysis

The main aim of the PhD activity here presented is the analysis and the proposal of methodologies that can be used for the integration of Computer Aided Engineering (CAE) tools starting from the early design phase of a vehicle. The topics described include the description of main factors pushing for the development of electric and hybrid electric vehicles, the description of model based engineering strategies through theory and examples, the proposal of guidelines for the definition of component models, the analysis of the use context of the city of Florence and the integration of such data on vehicle modelling environment. An application is then presented. The first part defines the context of analysis, aiming to explain the relevance of transport activities on a world basis and the drivers pushing for innovation in the automotive field. The potential of EVs for environmental impact reduction in terms of GHG emissions is explained. After that, a description of main explicit and emerging design goals and the potential related to the use of a structured approach for the integration of CAE tools in vehicle design process is proposed, thus defining a strategy for effective “concurrent engineering” activities during product development process. Literature data are collected and presented to support this section, from general modelling approach definition to the implementation in calculation tools having different capabilities and scopes, aiming to achieve a compromise between accuracy and simulation effort. The description include some notes about the low and high level communication methodologies between tools. These topics are described in detail in chapter 3. The strategy offers guidelines for the description of mechatronic components inside simulation environment. Various example applications are proposed and models used in literature are described. The characteristics of the model to be used in each phase are therefore different depending on the accuracy needed (e.g. from primary vehicle sizing to detailed power, energy, efficiency sizing) or on the focus of the design step. The description of model functionalities depending on simulation goal includes guidelines for the definition of model characteristics and of their input/output ports. The detail is on those powertrain components that are differentiating electric vehicles in comparison with conventional vehicles: battery, motors, inverters and converters. Due to the fact that real world driving data are needed for the calculation of effective performances and energy consumption of electric vehicle, an introduction on driving cycle analysis and development is proposed. Chapter 4 offers a brief review of significant literature works and of known synthesis methodologies, while Chapter 5 describes the measurement activity performed by the Candidate. This phase includes measurements, analysis, treatment and then a procedure for data selection and driving cycle generation is proposed and implemented; the result is a set of driving cycle related to electric vehicles use in the context of the city of Florence. The procedure can also be applied for continuous generation of driving sequences interfacing with simulation models. Chapter 6 describes the final application, including the modelling of an electric vehicle using a “range extender” (EREV) and the assessments of its performances within a