Development of a simulation model for energy balance in Heavy-duty truck driving missions

In the automotive industry, and especially in the heavy-duty sector, one of the main problems is the one of energy balance. This topic includes three main elements: the alternator, the battery, and the loads; the alternator should charge the battery and supply the loads when the vehicle is moving, while the battery provides the necessary current to the loads when the alternator is not working. Considering a daily truck mission, the night zone represents one of the most critical periods of the mission because the driver utilizes different loads during the night, especially the parking cooler, which absorbs a lot of energy. Also, the driver’s behavior is unpredictable since it is unknown how much power will be consumed. These factors will lead the battery to supply a lot of energy to satisfy the loads, which leads to a high battery discharge. On the other hand, in the morning, the driver will perform the engine cranking to start the vehicle, which causes a high current discharge and requires a certain minimum state of charge to be possibly done. In this context, this thesis focuses on realizing and validating an energy balance simulator for heavy-duty commercial vehicles. It is essential for the truck to have a good energy balance and for the driver to perform the cranking in the morning, minimizing the damage caused by the parking cooler during the night as much as possible. As a first step, an introduction about the types of trucks and engines present in Iveco is given, and the problem is stated, as well as research about the emissions regulation for heavy-duty vehicles is performed. Then, a study about the main two components, the alternator and the battery, is done. Later on, the input data given in spreadsheets are presented; these inputs are the ones to be used to start with the model definition and upgrade it during the work. Afterwards, the design of a simplified simulation model starts using Matlab/Simulink, with the purpose of defining the final model structure; some trials are made to make the model work properly and reach the expected results. Then, different alternator and battery types are implemented, alongside different driving mission and load profiles differentiated by type, and a switch logic is implemented to allow the user to choose between different alternators, alternator pulley ratios, and batteries, and compare the results after running the simulation. Moreover, a user-friendly mask is created to allow the user to choose between different types of missions, driving styles, alternator types, tau ratios, etc., and perceive the display of all the expected results. Then, the model is updated, allowing the study of different truck types in a simulation that includes a full day for the truck driver, and some assumptions are neglected, making the model closer to a real truck’s behavior. Finally, conclusions with a summary of the work, critical comments about the obtained results, and the possible future work perspectives complete this thesis.