Citation: Piancastelli, L.; Toccaceli, M.; Sali, M.; Leon-Cardenas, C.; Pezzuti, E. Electric Hybrid Powertrain for Armored Vehicles. Energies 2023, 16, 2605. https:// doi.org/10.3390/en16062605 Academic Editor: Thanikanti Sudhakar Babu Received: 16 January 2023 Revised: 1 March 2023 Accepted: 7 March 2023 Published: 9 March 2023 Copyright: © 2023 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). energies Article Electric Hybrid Powertrain for Armored Vehicles Luca Piancastelli 1, *, Marco Toccaceli 1 , Merve Sali 1 , Christian Leon-Cardenas 1, * and Eugenio Pezzuti 2 1 Department of Industrial Engineering, Alma Mater Studiorum Università di Bologna, Viale Risorgimento, 2, 40136 Bologna, Italy; marco.toccaceli@studio.unibo.it (M.T.); merve.sali2@unibo.it (M.S.) 2 Engineering Department “Mario Lucertini”, Università degli Studi di Roma Tor Vergata, Via del Politecnico, 1, 00133 Roma, Italy; pezzuti@mec.uniroma2.it * Correspondence: luca.piancastelli@unibo.it (L.P.); christian.leon2@unibo.it (C.L.-C.) Abstract: The performance of modern, new generation-armored vehicles would greatly benefit from overall engineering, optimization, and integration techniques of advanced diesel engines-electrified transmissions. Modern axial flux electric motors and controllers are perfectly able to replace the classical automatic gearbox and complex steering system of traditional Main Battle Tanks. This study shows a possible design of a serial hybrid electric power pack for very heavy tanks with a weight well over 50 tons. The result is a hybrid power system that improves the overall performance of armored vehicles off-road and on-road, improving the acceleration and the smoothness of the ride. In addition, fuel consumption will be reduced because the internal combustion engine operates at fixed rpm. The electric motors will outperform the traditional engines due to their very high torque output even at “zero speed”. The weight of a hybrid system has also been calculated. In fact, in many cases, it is possible to use all off-the-shelf components. The on-board diagnosis of the subsystems in the hybrid powertrain makes it possible to achieve a Time Between Overhaul (TBO) of 4500 h with a failure probability inferior to one in 10,000. Keywords: heavy vehicles; MBT; hybrid powertrains; EV 1. Introduction The National Academies of Sciences, Engineering, and Medicine said in a comprehen- sive report that future battlefields will require new investments in modern energy sources. This will include a new focus on existing aviation jet-fuel, diesel, and bio-diesel. Stating that all-electric vehicles are not yet reliable enough, the study appointed the Academies’ Committee to provide manned and unmanned vehicles for the next generation army needs. Research funded by the Army Undersecretary of Research and Technology has guided the future US Army Academy of Nutrition Committee in energy demands of alighted soldiers, armed and unmanned vehicles, and forward base of operations for future potential combat zones. The report examined advances in batteries, generators, and power transmission systems. In spite of the military’s interest in EVs, the study “Powering the US Army in the Future” [1] notes that fully-electrical combat platforms are impractical in present times. This conclusion came because the energy density of today’s batteries is considerably smaller than that of fossil fuels, the report said. This would result in excessive weight and volume to accommodate maneuvering needs. In addition, recharging all-electric vehicles in a short time demands large amounts of electrical energy not available on the battlefield, according to the study. However, the commission concluded that future inventory of the service “should be Hybrid Electric Vehicles (HEV) with Internal Combustion Engines (ICE), not all battery electric vehicles” [2]. 1.1. Hev Configurations There are two fundamental HEV configurations: Parallel (PHEV) and series (SHEV). Conceptually, the SHEV is an electric vehicle whose ICE and electric generator keep the Energies 2023, 16, 2605. https://doi.org/10.3390/en16062605 https://www.mdpi.com/journal/energies