Well-to-Wheel analysis of a full-electric performance powertrain in warm weather with energy optimization scenario

The climate change and the indirect health effects have taken to a growing attention in reducing the greenhouse gas emissions (GHG). Road transportation has the highest footprint (70% vs. other transports), hence the European Union (EU) has reinforced the regulatory framework, establishing the rule out of internal combustion engines architectures (ICE) by 2035. To gradually approach the transition, the law provides for an intermediate step in 2030 setting -55% of GHG compared with 1990. All this translates in a widespread interest for greener technologies as full-electric vehicles (BEVs), leading historical Carmakers to innovate their fleet. In most Countries the energy generation is not close to be carbon neutral, because it is still derived by coal or other fossil fuels. Thus, the aim of this thesis project is to perform a Well-to-Wheels analysis (WTW) of a performance full-electric passenger car both for track and daily routine usage. The assessment has been done over different missions and driving conditions, with a growing intensity: from the homologation cycle (Worldwide Harmonized Light Vehicles Test Cycle, WLTC) to Mistoalfa track that has the higher acceleration peaks. The first step of the analysis has been the review of on-track tests data, to identify the parameters affecting the energy consumption, as the battery temperature and the road slope. On second hand, a MATLAB/Simulink model of the powertrain has been built up using the Simulink powertrain blockset. The blocks have been customized with the detected parameters, minimizing the error with respect to the collected data. To improve the vehicle global energy consumption, a dedicated control algorithm of the regenerative breaking has been proposed, since it is not implemented in the real model. Moreover, the Thermal Management System (TMS) has been modelled in order to simulate possible optimization scenarios. The temperature has been taken under control to avoid the overheating effect, that is a phenomenon affecting the performance of the vehicle: it limits the output power and cause a progressive thermal aging. The simulation results have been compared with the carbon footprint of two hypothetical versions of the analysed vehicle equipped with internal combustion engine (ICE): the conventional and the mild-hybrid architecture (MHEV). The first one has been modelled considering the consumption of a vehicle of the same Brand with similar performance; for the second one the consumption has been reduced by a percentage considering other already existing Company’s hybrid architectures. Consequently, the analysed BEV emissions are always lower than the conventional or hybrid vehicle, even considering the heaviest driving cycle with the European carbon intensity. However, splitting the results by country, there is a significant variation on the BEV’s convenience: in some cases, emissions can result equivalent to ICE. Therefore, a Total-cost-of ownership analysis (TCO) has been done leading to the result that a full electric vehicle become cost-convenient if charged with domestic wall-box or AC charge, while the result has a wide variation by country, considering the ultrafast DC charge. In conclusion, it is not possible to define the effectiveness of BEVs beforehand, because it strongly depends on how green the energy generation is, on the mission and on the driving style.