Progettazione preliminare e analisi strutturale di un motore a due tempi a pistoni contrapposti alimentato a idrogeno per applicazioni ad alte prestazioni

The decarbonization of the automotive sector is a critical challenge for achieving global climate targets, as road transport accounts for a significant share of CO2 emissions, with passenger vehicles contributing nearly half. Hydrogen-fueled internal combustion engines offer a promising pathway toward low- or zero-emission mobility, particularly where electric technologies are limited by infrastructure or raw material supply. Hydrogen enables carbon-free combustion, but high flame temperatures cause nitrogen oxides (NOx) formation. NOx reduction requires lowering peak combustion temperatures, achievable with ultra-lean hydrogen-air mixtures, though this reduces engine power compared to conventional gasoline engines. In this context, the two-stroke opposed-piston engine emerges as a suitable architecture, combining high specific power with improved thermal efficiency. Opposed-piston engines feature two pistons moving in opposite directions within a single cylinder, controlling intake and exhaust ports, which enhances volumetric efficiency and air charge per cycle. This work investigates key opposed-piston engine design aspects differing from conventional engines, including crankshaft interaction, cylinder arrangement, crankshaft phasing, engine balancing, and dynamic response. Two configurations, 3-cylinder and 4-cylinder, were analyzed to capture general trends and design insights. A combined methodological approach was adopted, integrating preliminary analytical models with detailed numerical analyses. Multibody simulations using AVL Excite evaluated dynamic behavior and torsional vibrations. Results demonstrate that hydrogen-fueled opposed-piston engines can achieve high specific power and compact dimensions while meeting stringent emission requirements. The study provides design guidelines and methodological strategies that can support both early-stage development and performance optimization of future opposed-piston engines. Overall, opposed-piston engines represent a viable solution for sustainable, high-performance propulsion in the next generation of low-emission vehicles.