Performance analysis and Make-or-Buy evaluation of a hybrid drivetrain for a tracked vehicle

Electrification has become a defining force in the automotive industry, transforming the sector as traditional OEMs add hybrid and electric models while new BEV-focused players grow rapidly. Once a niche, electrification is now a structural shift, accelerated by environmental and regulatory pressures, and is enabling new models of sustainable mobility. This trend can transfer from cars to heavy-duty vehicles, bringing benefits such as higher efficiency, reduced fossil fuel dependence, and improved sustainability. Leveraging proven automotive technologies in the conservative heavy-duty sector lowers R&D costs, speeds time-to-market, and supports political and social acceptance. For companies, advantages include fleet standardization, easier maintenance and training, shared components across platforms, and enhanced safety through advanced electronic systems. It also reduces obsolescence, strengthens supply chains, and allows modular, scalable solutions for different vehicle needs. However, challenges remain. Heavy-duty applications face lower efficiency under constant load, added weight and cost from large batteries, payload reduction, and demanding thermal and energy management. High development costs, especially in small fleets, add to the problem, as do complex maintenance needs and limited component standardization. Training for drivers and technicians is also critical, given the shift in operational habits required. Tracked vehicles, due to their robustness and use in harsh conditions, also fall under this category. The structure of this thesis is organised into five chapters. The first chapter presents the thesis outline and the general motivations behind the work. In the second chapter, hybrid architectures for road vehicles and their elementary components are firstly explained. This is followed by a brief explanation of tracked vehicles and how they work. Chapter 2.4 deals with mechanical Cross-Drive and how it increases transmission efficiency and then Chapter 2.5 discusses, respectively, Independent Dual Electric Drive and Cross-Drive Electric Transmission, the two hybrid architectures analysed in depth in the thesis. In the third chapter, a steady-state analysis is performed based on working points representative of some manoeuvre that the vehicle must be able to perform. This part has been used to derive formulas and select the proper electric motors to be analysed. In the fourth chapter, a dynamic analysis is performed based on empirical data derived from real circuit measurements. This analysis verifies that the chosen electric motors ensure that the vehicle achieve at least performances of previous models. In this pursuit, MATLAB has been used to develop a comprehensive mathematical framework. This framework replicates the power-flows of a hybrid tracked vehicle, capturing its interactions with the environment and its various components, and covering both mechanical and electrical domains. The fifth chapter examines whether to internalise or outsource production of the components required for these hybrid architectures. The aim of this part is to develop a structured methodological approach that can be applied to industrial decision-making.