Energy balance of a vehicle

Abstract: Simulation has become a very useful tool to predict the characteristics of a system and perform analysis of parameters without having to run too many tests. The advanced system engineering team of Continental Automotive uses a 0D simulation program, AMESim, to realize simulations of vehicle models. These simulations are used e.g. to predict the fuel consumption and CO2 emissions. A tool has been developed over the course of previous internships to realize the energy balance of AMESim vehicle models, which goal is to check the consistency of the models (no creation or loss of energy) and simplify their analysis. In this thesis, this tool has been further improved and developed through a comprehensive analysis. The computations have been checked and corrected to fit best with the AMESim results and obtain a consistent energy balance. The program has been adapted to hybrid vehicles and combustion losses computations were introduced. The program is coded in Matlab for the computations and in HMTL and JavaScript for the display. After the program was validated, it was used to realize a study on CO2 emissions. Three vehicle models were used. The influence of some parameters on the CO2 emissions was analyzed: the mass, aerodynamic resistance, rolling resistance, frictions and electric load. The aim of the study was to assess which parameters had the most influence on the CO2 emissions reduction in the perspective of the 95 g/km goal by 2020 set by the European Union. It was shown that the parameters have different effects on the vehicles CO2 emissions and that this effect varied from one vehicle to another. Substantial CO2 reduction can be achieved by improving some parameters, which makes it possible for the diesel vehicles to reach the 95 g/km in 2020 target set by the European Union. However, to achieve this goal with gasoline vehicles, the resort to hybridization will probably be needed. To assess the possible benefits of hybridization, a fourth vehicle model featuring mild hybridization was used. However, the decrease of CO2 emissions enabled by this type of hybrid vehicle would still not be sufficient to meet the 95 g/km target with gasoline vehicles.