Browse Topic: Fuel cell vehicles

Items (636)
With the rapid development of the global economy, issues such as the energy crisis and environmental pollution have become increasingly severe. Owing to their environmental friendliness, structural simplicity, and high energy efficiency, electric vehicles have attracted widespread attention. Electric drive technology serves as the most promising and versatile propulsion solution for battery electric vehicles, hybrid electric vehicles, and fuel cell vehicles. As an advanced mechatronic transmission system, the electric drive axle offers high transmission efficiency, flexible packaging, and ease of digital and active chassis control integration, and has thus been increasingly adopted in modern vehicle architectures. The differential is a key component within the electric drive axle, responsible for regulating the rotational speed difference between the left and right wheels and ensuring balanced torque distribution. It plays a decisive role in vehicle stability and traction performance. This study focuses on the reliability testing methodology for differentials in electric drive axles, primarily including the extraction of reliability test conditions and the feasibility analysis of the proposed testing scheme. Specifically, based on the parameters of a given electric vehicle, a Simulink model of the motor and differential is established, and a complete four-wheel-drive vehicle model is constructed. Through simulation under typical driving conditions, operational data of the rear-drive axle differential are obtained. The collected data are then preprocessed and subjected to dimensionality reduction using Principal Component Analysis. The selected principal components are further analyzed using K-means clustering to construct representative differential reliability test conditions. The limitations of existing testing methods are analyzed based on the simulated results and relevant literature. Finally, a reinforced fatigue testing method for the differential is designed according to the extracted test conditions, and the feasibility of the corresponding test bench is evaluated.
Zheng, HongyuLi, ZiyuWang, DajiangTian, Kai
Polymer electrolyte membrane (PEM) fuel cells represent one of the most promising solutions for decarbonizing powertrain technologies, as they can be employed as carbon-free electrical power source. However, performance degradation during their operating lifetime - caused among other factors by non-uniform reactant distribution and improper membrane humidification, which may lead to the formation of local hot spots - remains a significant challenge. Computational fluid dynamics (CFD) tools represent an effective approach for investigating the transport of oxygen and hydrogen within the cell and for optimizing the geometry of PEM fuel cell flow distributors. Thus, they can be exploited in order to improve the uniformity of current density and temperature distributions over the cell active area. In this work, a serpentine flow field PEM fuel cell is considered as test case. The distributor consists of a multi-pass serpentine flow-field composed of repeated sets of five parallel channels interconnected by transverse manifolds. First, an open-source simulation library based on the OpenFOAM framework is validated against the cell polarization curve experimental data. Subsequently, a parametric analysis of the most relevant geometric parameters characterizing the flow distributor, such as channel width, channel height and manifold geometry, is carried out to assess their influence on the overall cell performance, reactants and current density distribution. The results demonstrate that appropriate optimization of the manifold geometry leads to a more uniform flow field within adjacent channels in both the anodic and cathodic distributors, resulting in an overall optimization of the pressure drop over the manifold, resulting in more efficient cell considering a balance of plant point of view.
Bulgarini, MargheritaDella Torre, AugustoMontenegro, GianlucaBaricci, AndreaMereu, RiccardoLalangui Gallegos, Jose A.De La Morena, Joaquin
Hybrid-electric (xHEV) and fuel cell electric vehicles (FCEVs) are expected to play a crucial role in the transition towards sustainable mobility in both the individual and commercial transportation sectors. As their market share increases, there is a need for advanced research to enhance overall vehicle efficiency – particularly through optimized energy management systems. For FCEVs, an optimal energy management strategy is essential to ensure safe and durable operation. For xHEVs, thermal management serves as a central lever for improving efficiency and controlling emissions, making it an integral part of the overall powertrain development process. Considering today’s regulatory landscape, these aspects must be addressed early in development. Consequently, a holistic methodological framework is required, enabling not only technical robustness but also economic benefits, such as reducing engineering effort through effective frontloading. This methodology is composed of integrated simulation and testing approaches to develop components, systems, and operation strategies for future vehicles. Building on component- and system-level evaluations conducted at a dedicated thermal system testbed (ThermoLab), vehicle-level testing is required to calibrate and validate the laboratory results. To bridge the gap between the testbed and real driving events, an innovative approach is developed to replicate essential real-world boundary conditions, with particular focus on thermal and hydraulic conditions. The combination of a dedicated low-temperature extension chamber and an innovative dynamic coolant conditioning unit enables the energy-efficient transfer of thermal and hydraulic boundary conditions to a classic chassis dynamometer that was previously incapable of low-temperature testing. While the dedicated low temperature extension chamber transfers low temperature boundary conditions to the vehicles surrounding, the dynamic conditioning unit (Dynamic Module III) enables the accurate reproduction of relevant temperatures within the vehicle’s powertrain. This study demonstrates an innovative approach for the energy-efficient transfer of real-world low-temperature boundary conditions on a chassis dynamometer incorporating low-temperature extension and dynamic conditioning units as part of a holistic development methodology.
Lavall, PhilippBeidl, ChristianFiore, LuisPapavasileiou, IoannisHohenberg, GünterKalski, Christian
Fuel cell electric vehicles are described on cell, stack and system levels. In driving operation, multi-physics coupling across subsystems (reactant supply, humidification, thermal management, etc.) reshapes cell- and stack-level boundary conditions, impacting performance and degradation mechanisms. Isolated single-topic approaches on one specific level may have limited transferability, as cross-level interdependencies under changing operating conditions can negate improvements or shift limiting factors. This underscores the development of validation environments (VEs) that represent cross-level interactions and evolve as experimental evidence redirects research questions. Models such as the V-Model provide phase-oriented logic for developing VEs when validation scope, boundary conditions and acceptance criteria can be specified upfront and remain stable. However, in PEMFC VE development, experimental conclusions frequently reshape hypotheses, operating conditions and research topics across successive cycles. Consequently, existing approaches often provide limited methodological support for a traceable and repeatable evolution of VEs where iterative reconfiguration is essential. To address this need, we developed the Development Model of the Validation Environment (eMVU, German for Entwicklungsmodell der Validierungsumgebung) for PEMFC technology to enable a structured, model-based and iterative evolution of VEs. Embedded in the system triple of product engineering, the eMVU guides the iterative transformation of objectives into validation configurations (VCs) through model-based derivation of boundary conditions, test requirements and extension measures. It structures each development cycle into the five phases design, specification, implementation and commissioning, experiments and results processing, as well as derivation of measures with feedback of the resulting insights into the objectives of the subsequent cycle. The framework is demonstrated by realizing a fully functional baseline VE and deriving an additional VC enabling semi-automated operation across eMVU cycles. Their implementation and operation provide experimental evidence that both the eMVU and the resulting VE enable traceable, repeatable and targeted assessment of cross-level interdependencies with measurable impact on cell and stack behavior.
Knaier, JohannesBause, KatharinaAlbers, Albert
Understanding the physiological impact of vehicle electrification on operators remains an important but underexplored issue in commercial vehicle research. This study quantitatively evaluates the physiological fatigue of drivers and onboard crew members during real-world operation of commercial refuse-collection vehicles by comparing a diesel-powered vehicle with a fuel cell electric vehicle (FCEV). Both vehicles were operated on the same routes under comparable real-world operating conditions, including similar time periods and operational tasks, during municipal waste collection service. Heart Rate Variability (HRV) metrics were obtained from R-R interval (RRI) data recorded using a Polar heart rate sensor. The Root Mean Square of Successive Differences (RMSSD), a time-domain index reflecting short-term parasympathetic activity, and Poincaré (Lorenz) plot area (LP area), a nonlinear HRV index reflecting overall autonomic nervous system modulation, were calculated. In-cabin vibration and noise levels were also measured as supplementary context to support the interpretation of physiological responses. The results indicate that both RMSSD and LP area were higher during FCEV operation than during diesel vehicle operation. For the driver, RMSSD increased by approximately 61.65% and the LP area by approximately 49.91%. For the onboard crew member, RMSSD increased by approximately 18.79% and the LP area by approximately 46.02%. These findings suggest a consistent association between reduced vibration and noise characteristics in the FCEV and increased HRV indices, indicating reduced physiological fatigue during operation. This study provides quantitative evidence that fuel cell electric commercial vehicles are associated with improved occupational conditions, extending beyond conventional environmental benefits.
Utsumi, AtsukoYakoh, Takahiro
The global automotive industry is accelerating its transition toward low-carbon solutions, with hydrogen fuel cell vehicles offering core advantages of zero emissions and extended range. Their critical component is the Type III fiber-wound hydrogen storage tank, whose performance directly impacts vehicle operational safety and driving range. This technology has now achieved widespread adoption. However, two significant challenges persist in the dome region of these tanks: first, modeling accuracy is difficult to control due to dynamic variations in thickness and winding angles; second, fiber thickness buildup frequently occurs near the pole holes. These issues compromise both the design reliability and manufacturing quality of hydrogen storage tanks. Therefore, this study adopted a combined approach of theoretical analysis and numerical simulation. First, based on composite mechanics theory and calibrated with experimental data (Tensile, Compression, and Shear Tests on NOL and Unidirectional Plates), the design methodology and key material parameters for the hydrogen storage tank were determined. Subsequently, through secondary development based on ABAQUS, rapid and high-precision finite element modeling was achieved. Results from the progressive damage model were validated against hydrostatic burst tests, controlling prediction errors within 3%, effectively resolving the modeling accuracy issue. Simultaneously, to address the fiber buildup problem, this study innovatively proposed two process solutions: bandwidth-based hole expansion and extreme-value hole expansion. Numerical simulation comparisons demonstrated that the 1.5-times bandwidth hole expansion scheme is optimal, enhancing fiber distribution uniformity, reducing overall stress levels, and improving load-bearing capacity. These technical methods and research conclusions provide theoretical support for the design and manufacturing of fiber-wound hydrogen storage cylinders.
Wang, JianguoZhang, QianCao, XuewenZheng, XuanxuanLi, Jiajie
This standard provides background information and a hydrogen fuel quality standard for commercial proton exchange membrane (PEM) fuel cell electric vehicles. This standard also provides background information on how it was developed by the Interface Task Force (ITF) of the SAE Fuel Cell Standards Committee.
Fuel Cell Standards Committee
This standard specifies the communications hardware and software requirements for fueling hydrogen surface vehicles (HSV), such as fuel cell vehicles, but may also be used where appropriate with heavy-duty vehicles (e.g., buses) and industrial trucks (e.g., forklifts) with compressed hydrogen storage. It contains a description of the communications hardware and communications protocol that may be used to refuel the HSV. The intent of this standard is to enable harmonized development and implementation of the hydrogen fueling interfaces. This standard is intended to be used in conjunction with the hydrogen fueling protocols in SAE J2601 and nozzles and receptacles conforming with SAE J2600 and ISO 17628. It may also be used with future hydrogen fueling protocols at the discretion of those fueling protocols.
Fuel Cell Standards Committee
The US trucking industry heavily relies on the diesel powertrain, and the transition towards zero-emission vehicles, such as battery electric vehicles (BEV) and fuel cell electric vehicles (FCEV), is happening at a slow pace. This makes it difficult for truck manufacturers to meet the Phase 3 Greenhouse Gas standards, which mandate substantial emissions reductions across commercial vehicle classes beginning of 2027. This challenging situation compels manufacturers to further optimize the powertrain to meet stringent emissions requirements, which might not account for customer application specifics may not translate to a better total cost of ownership (TCO) for the customer. This study uses a simulation-based approach to connect customer applications and regulatory categories across various sectors. The goal is to develop a methodology that helps identify the overlap between optimizing for customer applications vs optimizing to meet regulations. To use a data-driven approach, a real-world customer usage pattern analysis was conducted to identify key performance metrics required to optimize driveline components. Additionally, the impact of certification requirements on vehicle performance is examined to ensure compliance while maximizing the benefits of the proposed optimization strategies. The findings of this research will provide valuable insights for manufacturers, enabling the development of trucks that are not only efficient and high-performing but also compliant with environmental standards, ultimately leading to a more sustainable future in the trucking industry.
Mohan, VigneshDarzi, Mahdi
Worldwide, the automotive industry is pivoting towards electrification and zero-emission vehicles (ZEV) to address greenhouse gas emissions and to meet net-zero emission goals. Although pure electric vehicles with rechargeable high-voltage batteries seem to be the most popular choice to achieve climate goals, hydrogen-powered vehicles are also seen by many as a viable technology to clean up the transportation sector. Hydrogen fuel cells and fuel cell-powered vehicles have been in development for a long time, and hydrogen internal combustion engines (ICE) have seen rapid development in the past few years. While the technological feasibility of hydrogen fuel cells and H2 ICE is being proven, the mass adoption of these technologies depends, along with other factors such as hydrogen infrastructure, upon financial feasibility as well. This paper presents a systematic analysis of the total cost of ownership (TCO) of hydrogen-powered vehicles, especially fuel cell electric vehicles. Different commercial vehicle categories are analysed to assess the vehicle classes and use cases where hydrogen fuel cell-powered vehicles can be a cost-effective alternative to conventional ICE and battery electric vehicles (BEV). The analysis also determines the factors that contribute most to TCO, which will help identify the areas that require improvement/development or policy support to make fuel cells and hydrogen power more widespread. The paper also analyses the sensitivity of TCO to different cost factors, such as hydrogen cost, which helps in establishing cost targets to make hydrogen-powered vehicles a cost-effective solution in the transition to zero-emission transportation. Finally, different market trends are analysed to predict the timelines in which fuel cell-powered vehicles can become cost-competitive with ICE and BEV.
Jacob, JoeChougule, Abhijeet
The globe is looking headlong to set up new benchmarks for the reduction of GHG (Green House Gases) considering short-term and long-term strategies. Efforts in the Internal Combustion Engines (ICE) domain have been accelerating to find an alternative way to reduce harmful emissions. Hydrogen is considered as a promising fuel to leapfrog this transition. Hydrogen fuel can be categorized into vast mobility areas viz. ICE and Fuel Cell Electric Vehicle (FCEV). Hydrogen fuel has attracted global attention from engine researchers due to the crude oil crisis and its rise in prices in recent years. This will serve the nation's goal towards carbon neutrality. Hydrogen has a few advantages such as less fueling time, higher heating value and more efficiency making it an eye-touching fuel for the automotive industry. In the contemporary FCEV segment, many fuel cell technologies have evolved, wherein the development of Proton Exchange Membrane (PEM) fuel cell technology has taken a new height for heavy-duty commercial vehicle applications due to its significant interest in the non-existent tailpipe CO2 emissions. Since electric vehicles are also being combined with hydrogen fuel and the opportunity persists to convert it into a hybrid system or FCEV. There is always a keen curiosity of the end user to know the mileage of a vehicle as a distinguishing measure of fuel economy. Thus, it is pertinent to determine the hydrogen fuel economy of the FCEV vehicle. This paper provides an insight into fuel cell fundamentals, the working principle of hydrogen fuel cell vehicles, vehicle operation modes and testing methodology to determine the fuel economy of FCEV based on the electric current method and pressure method. The vehicle (e-Bus) has been validated on a chassis dynamometer based on the prescribed DBDC Cycle in the AIS 049 standard to calculate the hydrogen fuel economy of the FCEV Bus. The multiple stacks of PEM fuel cells connected in series has been used along with the electric powertrain vehicle and estimation of its fuel economy are the focus of this paper.
Joshi, Ashish RajendraKandalgaonkar, SiddheshSontakke, Rushikesh
Affordable and clean energy has been one of the major objectives adopted by United Nations under the 2030 Agenda for Sustainable Development. In this direction, fuel cell electric vehicles have gained popularity in recent times due their efficiency and environmental friendliness. Fundamentally, it uses compressed hydrogen from the vehicle-mounted tank and combines with ambient air to generate DC electricity. Water is created as a by-product and expelled through the tailpipe. The technology being integrated on powertrain architecture, along with battery pack can prove to be an efficacious approach for zero emission automotive system. However, hydrogen being the primary fuel, and being stored at high pressure, the system involves handling and potential hazards of hydrogen, and possibility of explosions due to hydrogen leaks. Hence, safety is the key issue in handling fuel cell vehicles. This paper discusses about role of Unified Diagnostic Services (UDS) in providing safety and precautionary aspects for the fuel cell vehicles. UDS has been first time developed for fuel cell vehicle, in India in accordance with fault codes by fuel cell stack, applied on TML FCEV bus. It discuss about how UDS can be used to anticipate key safety issues such as hydrogen leaks, pressure monitoring system, and analyzing the Diagnostic Troubleshooting Codes (DTC) from fuel cell stack. In order to improve the dependability, durability, and safety of fuel cell vehicles (FCVs), diagnostic services are essential since they assist in the real-time detection and identification of defects. Apart from identifying DTC codes from the stack, this paper also discuss about how the key UDS services like, diagnostic and communication management services, data transmission services, input output control services, etc. can be implemented for the fuel cell controller unit (FECU). As a part of novelty, the role of AUTOSAR modules such as DEM and DCM in handling the faults has also been discussed in brief.
PRASAD, Dr. P SHAMBHUJacob, JoeHadke, TanmayWagh, PriyankaAchanur, Mallappa
Growing global warming and the associated climate change have expedited the need for adoption of carbon-neutral technologies. The transportation sector accounts for ~ 25 % of total carbon emissions. Hydrogen (H2) is widely explored as an alternative for decarbonizing the transport sector. The application of H2 through PEM Fuel Cells is one of the available technologies for the trucking industry, due to their relatively higher efficiency (~50%) and power density. However, at present the cost of an FCEV truck is considerably higher than its diesel equivalent. Hence, new technologies either enabling cost reduction or efficiency improvement for FCEVs are imperative for their widespread adoption. FCEVs have a system efficiency around 40-60% implying that around half of the input energy is lost to the environment as waste heat. However, recapturing this significant amount of waste heat into useful work is a challenge. This paper discusses the feasibility of waste heat recovery (WHR) technology for a long-haul FCEV heavy duty truck with a rated power of 300 kW. Two WHR system are evaluated – widely used Organic Rankine Cycle (ORC). Working fluids considered for the ORC model are R1233zd(E), R245fa and n-Pentane. The 0-D model of the ORC based WHR systems is developed in Matlab-Simulink platform for analysis. The waste heat generated is quantified at different drive-cycles, namely flat, moderate hilly and hilly terrain, using a complete vehicle simulation tool developed in Simulink platform. The waste heat data from complete vehicle simulation tool is provided as an input for the developed 0-D WHR models. The results show a considerable improvement in the overall fuel consumption of FCEV trucks with WHR systems. The findings imply the importance of WHR in FCEV truck to improve the overall system efficiency.
P V, Navaneeth
The transportation and mobility sector are undergoing a profound transformation, with a growing emphasis on sustainability and minimizing the environmental impact of transportation. Among the most significant trends is the transition to electric vehicles (EVs) in the form of Battery and Fuel cell, which produce zero emissions without any harmful gases release in nature. This review highlights several infrastructure-related issues and critical factors that could drive India's transportation sector toward adopting electric vehicles. It also delves into the fundamental understanding of e-mobility, shedding light on the daily challenges and barriers it faces. Furthermore, the study explores research aspects, including the strategies, methods, and tools used for electric vehicles to complete the research on Battery electric vehicles (BEV) and also comparative analysis with Fuel cell vehicles (FCVs). The shift BEVs has been driven by decreasing battery costs and advancements in charging infrastructure, making EVs a more feasible choice. The review also examines the Indian government's approach to e-mobility and compares India's infrastructure with that of developed nations to identify key factors. Finally, it suggests major strategies and solutions to address challenges facing the Indian automobile sector. Collaboration between automotive industry stakeholders and government entities will be essential to overcome these challenges and foster EV adoption. This will ultimately help reduce carbon emissions and air pollution. Taken together, this review article will help in shaping a future of sustainable, efficient, and interconnected mobility.
Kumar, Dr. Vijay Bhooshan
Hydrogen Fuel Cell Electric Vehicles (FCEVs) are emerging as a sustainable solution to reduce greenhouse gas emissions in the transportation sector, in line with the Paris Agreement and global net-zero emission goals. This paper presents a comprehensive performance analysis of the FCEV powertrain under intercity and intra-city driving conditions. The study focuses on key parameters such as fuel cell system efficiency, energy consumption, hydrogen usage, and overall drivetrain response. Using simulation models validated with real-world driving data, the performance of the powertrain is evaluated across varying speed profiles, vehicle loads, and driving cycles. The analysis also considers the impact of auxiliary load including HVAC systems and consumption of other electric components on the powertrain efficiency and energy balance. Results highlight that the FCEV powertrain performs efficiently during intercity driving due to stable speed conditions and low stop-start frequency, while intra-city driving presents challenges related to dynamic load demands and energy recovery optimization. Additionally, the study discusses the sustainability benefits of FCEVs, refueling infrastructure needs, and policy frameworks required to support widespread deployment. Overall, the findings demonstrate the capability of hydrogen-powered electric drivetrains to meet the demands of both urban and long-range transport while supporting long-term de-carbonization strategies.
Patil, Nikhil N.Bhardwaj, RohitSaurabh, SaurabhAhmed, YasirGawhade, RavikantAmancharla, Naga ChaithanyaGadve, Dhananjay
In current scenario, demand for alternate energy is increasing due to depletion of fossil fuels and countries working to achieve carbon neutrality by 2050. Hydrogen being a cleaner fuel, many OEMs across the world started to work on various strategies like hydrogen combustion engine and fuel cell. Passenger vehicles like buses are at the lookout for fuel cell technology at faster rate than other commercial vehicles. In fuel cell vehicles, cooling system design is critical & complex since it includes fuel cell cooling, Power electronics cooling & battery cooling. In this paper, cooling system design of a Fuel cell electric bus for inter-city application is demonstrated. Radiators and Fans are designed considering overall heat rejection and Coolant inlet temperature requirements of components. Cooling system circuit and pump is decided to meet the coolant flow rate targets. Flow simulation and thermal simulation done with the help of simulation models built using software KULI to predict coolant flow rate and temperature across each component. Fuel cell circuits, Power electronic circuits, Battery circuits modelled in KULI with all components in the circuit. KULI predicted results signifies good co-relation with actual results.
M S, VigneshKiran, Nalavadath
Hydrogen Fuel Cell Electric Vehicles (FCEVs) represent a significant trajectory in vehicular decarbonization, harnessing the inherently high energy density of diatomic hydrogen within electrochemical conversion systems. When sourced via renewable pathways, such hydrogen facilitates propulsion architectures characterized by zero tailpipe emissions, enhanced energy efficiency, and extended operational range profiles. Realizing peak systemic efficacy necessitates the synergistic orchestration of high-fidelity fuel cell stack design, resilient compressed gas storage modalities, and nuanced energy governance protocols. To reduce transient stressors and guarantee long-term electrochemical stability, employing multi-scale modeling and predictive simulation, combined with constraint-aware architectural synthesis, is crucial in handling stochastic driving conditions spectra. This study develops a high-fidelity mathematical plant model of a hydrogen Proton Exchange Membrane (PEM) fuel cell vehicle and implements advanced Energy Management Strategies (EMS). The FCEV plant model is developed with the forward approach method, taking into account the power limitations of the power plant. A PEM fuel cell system is accurately and in detail modeled, representing voltage loss mechanisms. The performance of the mathematical model was calibrated with the experimental results with an error margin of 8-10%. Whereas, a permanent magnet synchronous motor is modeled mathematically along with a Field-Oriented Controller (FoC) for ensuring precise torque regulation. Energy Management Strategies (EMS) optimize fuel cell and battery coordination to boost vehicle performance and efficiency. Online EMS adapts control using real-time data, while offline EMS applies machine learning to past driving patterns for predictive energy allocation. In this study, a Genetic Algorithm (GA)-based EMS, which is one of the types of offline EMS, is implemented to enhance fuel economy, dynamic performance, and component-level energy usage. Compared to non-optimized operation, the GA approach offers improved power split efficiency, 9-12% improvement in hydrogen consumption, resulting in lower energy consumption and enhanced overall vehicle performance. This work improves PEM FCEV technology through better design, simulation, and optimization methods, laying a solid foundation for future advancements in sustainable and efficient transportation.
Mulik, Rakesh VilasraoE, PorpathamSenthilkumar, Arumugam
In the recent years, the use of conventional passenger vehicles has been increasingly discouraged, from European-level policies to local municipal regulations, due to the urgent need to reduce greenhouse gas emissions and urban pollution. In response to these challenges, the PRIN2020 project HySUM (Hybrid SUstainable Mobility platform) explores innovative hybrid powertrain solutions for light and heavy quadricycles to achieve near-zero pollutant emissions, focusing on internal combustion engine hybrid electric vehicles and fuel cell hybrid electric vehicles. Taking all these aspects into consideration, this article proposes an integrated solution for cooling/HVAC circuits, to improve energy efficiency and occupants’ comfort, while focusing on proper battery operation, with a recuperator heat exchanger used to recover the available heat at the powertrain output, in order to reduce the HVAC heater energy consumption. The complexity of the circuit requires a specific control logic to be implemented to simultaneously ensure cabin comfort, effective thermal management of the battery, and minimize energy consumption. The study is applied to the HySUM fuel cell/battery hybrid L-class electric vehicle. A thermal and electrical model for predicting the heat generation and the state of charge of the battery under dynamic load profiles is employed to better understand the potential of the thermal integration of the battery cooling with the HVAC system. The simulation results are encouraging and demonstrate the effectiveness of the proposed thermal load management. Significant energy savings are achieved through the use of the recuperator during driving, while battery thermal management is accomplished without the need for a dedicated circuit, by utilizing conditioned air from the HVAC/cabin system. Unlike traditional lightweight electrified vehicles, which often lack efficient HVAC systems, this solution enhances energy efficiency and guarantees reliable component operation in varying environmental conditions.
Lombardi, SimonePutano Bisti, ChiaraFederici, LeonardoPistritto, AntoninoChiappini, DanieleTribioli, Laura
Ethanol is a hydrogen-rich liquid and has a specific energy of 8.0 kWh/kg. In a vehicle, hydrogen storage is done in high-pressure cylinders. The same fundamental technology is used at other fuel cell systems in vehicles such as Toyota Mirai and Honda Clarity. Hydrogen is also introduced into the cell to generate electricity, which will power an electric motor that drives the vehicle. Excess electricity is stored in batteries. The main characteristic of the system described here is that hydrogen can be generated through an additional process in a reformer, installed at a fixed station. The reformer transforms the ethanol stored in the fuel station tank into hydrogen, which can then fuel a vehicle equipped with high-pressure cylinders and fed into the fuel cell. The system, however, emits water vapor, heat, and CO2. This is because carbon dioxide is a byproduct resulting from the transformation of ethanol into hydrogen. According to studies, despite this the system is carbon neutral, considering the total cycle. That is, the CO2 released into the atmosphere is retained by the plantations that are cultivated to produce ethanol. Thus, the carbon is contained in a closed cycle. In addition to ethanol, the reformer can also operate with other fuels such as natural gas, biogas, etc. In view of these facts, we have the following considerations: the use of an electric traction system with a fuel cell powered by reformed hydrogen gas from ethanol can allow greater autonomy for electric vehicles, reducing the dependence on electric charging stations; it can also make a significant contribution to reducing pollutant emissions. Looking at the world situation in the medium term, it may turn out to be an alternative system to the use of internal combustion engines and reduce dependence on fossil fuels.
Fontana, Romeu
Powertrain architecture is being reshaped by the electrification of heavy-duty military vehicles using hydrogen fuel cell technology, particularly in transmission systems. Unlike conventional internal combustion engines, hydrogen fuel cell electric vehicles (FCEVs) typically use single-speed or direct-drive configurations due to the high torque of electric motors. This paper examines the impact of hydrogen electrification on military vehicle transmissions, focusing on armored multi-role models such as the VBMT-LSR, Guarani, and Leopard 1A5 of the Brazilian Army. The study compares traditional gearboxes with alternative solutions optimized for fuel cells, analyzing the trade-offs in efficiency, durability, and operational adaptability. Additionally, it explores adaptations required for hydrogen internal combustion engines (H2-ICEs), considering their distinct characteristics and demands. The study employs a three-step validation methodology combining computational simulations, technical data analysis, and case studies of military vehicles. MATLAB and similar tools are used to assess efficiency, durability, and torque response under field conditions. Next, specifications from existing military vehicles in the Brazilian Army are analyzed to evaluate the feasibility of hydrogen powertrains compared to diesel-based solutions. Finally, the study examines international military projects that have already integrated hydrogen or electrification, such as GM SURUS and Rheinmetall Mission Master, drawing insights into the applicability of these concepts in the Brazilian military context. This research enhances the understanding of hydrogen-powered transmissions, contributing to the future development of more sustainable powertrain solutions and thus supporting the adaptation of military fleets to alternative energy sources and accelerating the adoption of hydrogen-based mobility in defense applications.
Biêng, Ethan Lê QuangPontes, Guilherme AyrosoConrado, Guilherme Barreto RollembergLopes, Elias Dias RossiRodrigues, Gustavo Simão
With air resistance being one of the two major energy losses in on-road vehicles (the other one being tire losses) and therefore heavily contributing to the range of battery electric and fuel cell electric vehicles, it is necessary to account for realistic air resistance in a priori assessments like vehicle range estimations, component dimensioning, and system simulations. However, lack of input data tempts analysts to instead assume unrealistic “nominal conditions” throughout—a simplification which usually underestimates the amount of energy actually required to overcome air resistance and completely ignores the fact that varying environmental conditions will lead to significant variances in energy consumption and therefore vehicle range. Using “nominal conditions,” it is thus impossible to assess the robustness of these measures and, therefore, difficult to design robust systems and to perform meaningful trade-off studies. In this study, we show how publicly available data from weather observations can be used to assess the long-term variation of air resistance of a truck with a semitrailer. Realistic distributions of energy losses due to air resistance, covering multiple years, are derived—showing not only average values but the complete envelope in which the energy losses vary. This, in turn, enables to follow up with probabilistic calculations of vehicle performance in order to assess robustness and trade-offs on various system levels of interest. As a consequence, consumption and range predictions of EVs and ICE vehicles can be performed with higher accuracy and confidence.
Filla, Reno
The reliability and durability of vehicles are crucial for the acceptance of new technologies by customers. Realistic test methods are necessary to validate or ensure the lifespan of vehicles and their components, particularly regarding specific conditions such as freeze start. This article provides an overview of the current state of research on the effects of freeze starts on the degradation of fuel cells. With this knowledge, relevant operating and boundary conditions for potential damage of the fuel cell are identified (e.g. start temperature, duration in subzero operation, dehydration). The field data from the BMW demonstrator fleet of iX5 Hydrogen Next were analyzed to gain insights into realistic freeze start related stress to the fuel cells. The dynamics of heating rates and the influence of the operating strategy are best represented on a Fuel Cell System (FCS). An experimental setup for a stack centered test on a FCS was developed including a climatic chamber and a subzero coolant supply in this study. The identified automotive conditions could be implemented similarly and reproducibly for the stack. In total of 140 freeze starts with the start stack temperatures between - 7 °C and - 18 °C were performed. These test results and the vehicle data were compared, and the limitations of this accelerated stress test are stated. The advantage of this method is the feasibility to validate the lifetime regarding freeze starts within a period of 1-2 month in 24/7 operation. The occurred problems during test development and their solutions are also described, and suggestions for improvement for less damaging freeze starts process are given.
Schwarz, MarkusAlbert, AlbertEichel, Rüdiger-A.
Letter from the Guest Editors
He, XinBelgiorno, GiacomoJoshi, Ameya
This paper focuses on the potential application of hydrogen fueled internal combustion engine (HICE) in the off-road market, examining HICE based on a diesel engine. In the transition to HICE, priority was given to compatibility with existing systems, minimizing changes from the base engine. By adopting a PFI (Port Fuel Injection) method for fuel injection, low-pressure hydrogen supply was achieved. To address the issue of backfire associated with PFI, optimization of injection pressure using a variable pressure control valve, along with adjustments to valve timing and injection timing, was implemented to suppress backflow of residual gases into the intake system and minimize hydrogen retention. Regarding pre-ignition, in addition to suppressing hotspots, the relationship between the homogenization of the air-fuel mixture and NOx emissions was examined, revealing a correlation. This engine was mounted on a generator, and efforts were made to improve the important characteristic of responsiveness in generators. As a result, it was confirmed that the responsiveness is comparable to that of existing gas engine generators.
Shiraishi, KentaroKishi, ShinjiKato, DaichiMitamura, KentaMurakami, KeiMikuni, Yusuke
One of the major goals of the automotive industry is to improve vehicular fuel efficiency and performance with much lesser percentages of harmful tailpipe emissions. One of the major technologies includes fuel cell electric vehicles (FCEV). Various advantages of fuel cells including reliability, simplicity, quietness of operation, and low pollution have made them an attractive potential candidate for providing automotive power. Even with numerous benefits, fuel cell still have more potential to become more efficient during its operation as, when put inside a vehicle, many auxiliary components act as a parasitic load on the fuel cell system. Thermal management system is one of such system which is critical for working of the fuel cell yet takes large amount of electrical power to operate. At high power operation entire thermal management system can draw up to fifteen percent of total power generated by the fuel cell. This paper discusses on a real time optimizer which controls the various pumps, fans in the vehicle to maintain the temperature of fuel cell. The optimizer considers various inputs such as the current heat generated by fuel cell, current vehicle speed, current & target temperature of the fuel cell system and ambient temperature. The optimizer follows a dual-mode approach to balance need for quick response while maintaining stable long-term operation. The results highlight potential of this optimizer to operate with lowest possible electrical power for cooling components while providing highest possible cooling effect.
Choubey, AyushGehring, OttmarBunz, ChristofSöhner, Luisa
The transition towards sustainable transportation necessitates the development of advanced thermal management systems (TMS) for electric vehicles (EVs), hybrid electric vehicles (HEVs), hydrogen fuel cell vehicles (FCVs), and hydrogen internal combustion engine vehicles (HICEVs). Effective thermal control is crucial for passenger comfort and the performance, longevity, and safety of critical vehicle components. This paper presents a rigorous and comparative analysis of TMS strategies across these diverse powertrain technologies. It systematically examines the unique thermal challenges associated with each subsystem, including cabin HVAC, battery packs, fuel cell stacks, traction motors, and power electronics. For cabin HVAC, the paper explores methods for minimizing energy consumption while maintaining thermal comfort, considering factors such as ambient temperature, humidity, and occupant load. The critical importance of battery thermal management is emphasized, with a focus on preventing thermal runaway and maximizing battery lifespan through precise temperature regulation. The complexities of fuel cell stack thermal management are addressed, considering the electrochemical reactions and the need for uniform temperature distribution for optimal performance and durability. Furthermore, the paper investigates the thermal behavior of high-power traction motors and power electronics, analyzing different cooling techniques and their impact on efficiency and reliability. A comparative assessment of various cooling technologies, including forced air convection, liquid cooling, and emerging two-phase cooling methods, is provided. The paper also delves into integrating these individual TMS components, exploring opportunities for waste heat recovery and holistic system optimization. Finally, the paper identifies critical research gaps and outlines future directions in the development of intelligent and adaptive thermal management systems for next-generation electrified vehicles, emphasizing the need for robust control algorithms, advanced materials, and innovative cooling architectures.
K, NeelimaK, AnishaCh, KavyaC, SomasundarSatyam, SatyamP, Geetha
Zero emission vehicles are essential for achieving sustainable and clean transportation. Hybrid vehicles such as Fuel Cell Electric Vehicles (FCEVs) use multiple energy sources like batteries and fuel cell stacks to offer extended driving range without emitting greenhouse gases. Optimal performance and extended life of the important components like the high voltage battery and fuel-cell stack go a long way in achieving cost benefits as well as environmental safety. For this, energy management in FCEVs, particularly thermal management, is crucial for maintaining the temperature of these components within their specified range. The fuel cell stack generates a significant amount of waste heat, which needs to be dissipated to maintain optimal performance and prevent degradation, whereas the battery system needs to be operated within an optimal temperature range for its better performance and longevity. Overheating of batteries can lead to reduced efficiency and potential safety hazards, while low temperatures can decrease battery performance and range. The multiple temperature control loops in the thermal system design of the current FCEVs require significant energy for continuous heating and cooling. This is due to the fact that each of them exchanges energy directly with an external source or sink without redistributing energy among themselves. This can lead to energy losses during the heat exchange process. Our goal is to optimize thermal energy usage while maintaining the same performance and efficiency of both battery electric system and the fuel cell stack in a vehicle. In this paper, an analysis of thermal energy utilization of a single system is compared to the exchange of thermal energy across multiple systems, considering various heating and cooling scenarios. We compare our proposed strategy (with redistribution) with the existing strategy (without redistribution) quantitatively with respect to controller effort/ energy spent in achieving thermal target.
BHOWMICK, SAIKATChuri, Chetana
Fuel cell hybrid electric vehicles (FCHEVs) are a promising solution for decarbonizing heavy-duty transport by combining hydrogen fuel cells with battery storage to deliver long range, fast refuelling, and high payload capacity. However, many existing simulation models rely on outdated fuel cell parameters, limiting their ability to reflect recent technological improvements and accurately predict system-level performance. This study addresses this gap by integrating a state-of-the-art, physics-based model of a polymer electrolyte membrane fuel cell (PEMFC) into an open-source heavy-duty vehicle simulation framework. The updated model incorporates recent advancements in catalyst design and membrane conductivity, enabling improved representation of electrochemical behavior and real-time compressor control. Model performance was evaluated over a realistic 120 km long-haul drive cycle. Compared to the traditional fuel cell model, the updated system demonstrated up to 20% lower hydrogen consumption, significantly reduced compressor power demand, and improved cooling performance due to higher stack efficiency. Peak fuel cell efficiency approached 59%. The findings highlight the critical importance of using up-to-date fuel cell models in FCHEV simulations to enable accurate energy predictions and optimal system design. This work supports more effective deployment of zero-emission heavy-duty vehicles through improved model fidelity and control strategy development.
Dursun, BeyzaJohansson, MaxTunestal, Peraronsson, UlfEriksson, LarsAndersson, Oivind
SAE TOMORROW TODAY - Powering A Cleaner Commercial Vehicle Industry135328/29/2025
From battery-electric trucks to hydrogen fuel cell vehicles, the company behind Kenworth, Peterbilt, and DAF is leading the charge toward zero-emissions. PACCAR is a global technology leader in the design, manufacture, and customer support of premium light-, medium- and heavy-duty trucks. The company is also actively investing in zero-emission technologies, positioning itself as a leader in the transition to cleaner commercial vehicles. To learn more, we sat down with Dr. Philip Stephenson, General Manager, PACCAR Technical Center and Executive Chair of this year's COMVEC, the annual commercial vehicle engineering conference hosted by SAE International. Listen in for an engaging discussion on PACCAR's approach to battery-electric trucks, hydrogen fuel cell vehicles, and charging infrastructure partnerships. And if you enjoyed this conversation, register now for COMVEC and join us as we bring together industry leaders, engineers, and innovators to discuss the latest advancements in on- and off-highway mobility technologies. We'd love to hear from you. Share your comments, questions and ideas for future topics and guests to podcast@sae.org. Don't forget to take a moment to follow SAE Tomorrow Today--a podcast where we discuss emerging technology and trends in mobility with the leaders, innovators and strategists making it all happen--and give us a review on your preferred podcasting platform. Follow SAE on LinkedIn, Instagram, Facebook, Twitter, and YouTube. Follow host Grayson Brulte on LinkedIn, Twitter, and Instagram.
Patterson, Lori
Medium- and heavy-duty fuel cell electric vehicles (FCEV) have gained attention over the battery electric vehicles, offering long vehicle range, fast refueling times, and high payload capacity. However, FCEVs face challenges of high upfront system cost and fuel cell system durability. To address the cost sensitivity of the fuel cell powertrain, it is imperative to maximize the operating efficiency of the energy and thermal management system while meeting the fuel cell durability requirements. This article presents an advanced adaptive control strategy for each of the energy and thermal management systems of a FCEV to maximize operating efficiency as well as vehicle performance. The proposed adaptive energy management strategy builds upon a real-time equivalent consumption minimization strategy (ECMS), which is updated based on a horizon prediction algorithm using GPS and navigation data of the route. The algorithm predicts the battery state of charge (SOC) for a defined horizon, which is used to predict the target SOC for the real-time ECMS strategy to minimize hydrogen consumption. For a long-haul heavy-duty truck application, the proposed adaptive ECMS strategy showed 1.8% and 1% improvements in fuel efficiency when compared to rule-based and baseline ECMS strategies through model-in-loop (MiL) evaluation. In addition, this article presents an adaptive thermal management strategy that integrates predictive and real-time control approaches, such as the adaptive ECMS. The predictive control strategy leverages GPS and navigation data to forecast component temperatures over a predefined horizon prediction. The predicted component temperatures are then utilized to adjust the target component temperatures for the real-time linear quadratic regulator (LQR) control algorithm. LQR is deployed to minimize the energy consumption of the thermal management system while ensuring that component temperatures are maintained within limits during aggressive duty cycles. Lastly, MiL evaluations were conducted on a validated plant model to verify the developed adaptive thermal management control strategy.
Batool, SadafBaburaj, AdithyaSadekar, GauravJoshi, SatyumFranke, Michael
The primary approach to meet the objectives of the EU Heavy Duty CO2 Regulation involves decarbonizing the road transport sector by battery electric vehicles (BEV) or hydrogen-fueled vehicles. Even though the well-to-wheel efficiency of hydrogen-fueled powertrains like fuel cell electric vehicles (FCEV) and H2-internal combustion engines (H2-ICE) is much lower in comparison to BEV, they are better suited for on-road heavy-duty trucks, long haul transport missions and regions with scarce charging infrastructure. Hence, this paper focuses on heavy-duty FCEVs and their overall energetic efficiency enhancement by intelligently managing energy transfer across coolant circuit boundaries through waste heat recovery, while ensuring that all relevant components remain within required temperature boundaries under both cold and hot ambient conditions. Results were obtained using a 1D-model that comprises all thermal fluid circuits (refrigerant, coolant, air) created through GT-Suite software. This model was utilized to simulate heat distribution during various road transport missions, such as alpine crossing via Brenner Pass from Munich (Germany) to Modena (Italy). Depending on load cycle profile and ambient conditions significant fuel savings were demonstrated. Furthermore, by coupling the high-temperature circuit of the fuel cell with the low-temperature circuit of the battery via a water/water heat exchanger, there is no need for additional electric heating via an electric heating element (PTC) within this circuit. In more extreme ambient conditions, utilizing recovered heat solely from high-temperature fuel-cell circuit is not sufficient; thus, cabin heating (HVAC) requires further measures such as an additional PTC or system heat pump to achieve an acceptable pull-up time of the cabin.
Uhde, SophiaLanghorst, ThorstenWuest, MarcelNaber, Dirk
Faced with one of the greatest challenges of humanity – climate change – the European Union has set out a strategy to achieve climate neutrality by 2050 as part of the European Green Deal. Life Cycle Assessment (LCA), which among other aspects identifies climate change effects, is an important tool to assess the environmental characteristic of sustainable technologies or products to fulfill this ambitious target. In this context, research is presented that examines the ecological sustainability impacts of a metallic vs a composite bipolar plate made of innovative graphite-compound based foils for fuel cell applications. A bipolar plate is a central component of the fuel cell stack to ensure efficiency and durability. For this purpose, a LCA is performed for both bipolar plate materials. This assessment follows the methodology of DIN EN ISO 14040/44 and the EU Product Environmental Footprint framework. Focusing on cradle-to-gate system boundary conditions, the research emphasizes the manufacturing processes with the relevant material and energy flows. Dealing with uncertainties in the energy supply chain, a comprehensive sensitivity analysis is conducted defining current and future energy scenarios with various shares of renewable and fossil energy carriers. Furthermore, the impact of different material production locations on the outcome of the LCA is investigated, considering changing geopolitical conditions. To assess also the effect on a fuel cell stack, the study continues with a cradle-to-gate evaluation of the fuel cell system. Afterwards, to also consider the complete lifetime of a fuel cell vehicle, the study is extended to cradle-to-grave system boundary conditions for a C-segment SUV. Besides the evaluation of the global warming reduction potential, the study deals with the impact of the production processes of both bipolar plates on other impact categories like freshwater eutrophication or acidification. The investigations have shown that the use of foil-based graphite-compound bipolar plates can reduce the global warming potential by up to 75% compared to conventional steel bipolar plates.
van Sloun, AndreasSchroeder, BenediktKexel, JannikSchmitz, MaximilianBalazs, AndreasWalters, MariusKoßler, SilasPischinger, StefanJoemann, Michael
The automotive sector in India is undergoing a transformation, driven by government policies and regulations aimed at achieving net-zero carbon emissions. In alignment with global climate goals, the Indian government has set ambitious targets to reduce greenhouse gas emissions, with a focus on promoting Electric Vehicles (EVs) and Hydrogen Fuel Cell Vehicles (FCVs). Initiatives like the Faster Adoption and Manufacturing of Hybrid and Electric Vehicles (FAME) Scheme, along with tax incentives, subsidies, and charging infrastructure development, are designed to accelerate the adoption of cleaner vehicles. The introduction of stricter emission standards and the National Electric Mobility Mission Plan (NEMMP) further underscores the push toward sustainable mobility. In response, Indian automotive companies are shifting strategies to align with these government directives. Major players are significantly increasing investments in EV technology, focusing on enhancing battery performance, expanding manufacturing capacities, and improving charging networks. Meanwhile, hydrogen fuel cell technology is being explored as a potential solution for specific sectors like long-distance trucking and buses, with pilot projects underway to assess the feasibility of hydrogen infrastructure in India. The future market trends in India point toward rapid growth in both EVs and FCVs, driven by supportive government policies, evolving consumer preferences, and advancements in technology. As India moves toward its carbon-neutral goals, the automotive industry’s shift to zero-emission vehicles is pivotal. This paper explores the synergy between government regulations, automotive industry strategies, and market dynamics in shaping India’s transition to a sustainable transportation future.
Patil, Nikhil NivruttiSaurabh, SaurabhBhardwaj, RohitGawhade, RavikantGadve, DhananjayAmancharla, Naga Chaithanya
Tarek Abdel-Baset, Forvia's chief engineer for hydrogen storage systems, has two decades of experience in alt-fuel transporation development, with all the ups and downs that entails. So he was a good person for SAE Media to ask about the industry vibe at the 2025 Advanced Clean Transportation Expo in Anaheim.
Clonts, Chris
The growing demand for air transport requires efficient and sustainable power systems to meet the pressing need for decarbonizing the sector. A hybrid unit, consisting of a proton exchange membrane fuel cell system and a lithium-ion battery, is a suitable option due to the advantages of reduced gravimetric and volumetric impacts, along with the flexibility of energy management strategies. This work addresses, using a model-based approach, the issue of integrating these electrochemical devices into the aircraft’s electrical architecture considering both design and energy management aspects. A literature derived DC-DC converter bi-dimensional power map is exploited to investigate scenarios differentiated by the fuel cell system power rating and number of stacks working in parallel such that the DC bus line voltage requirements can be respected. These maps relate the converter’s maximum deliverable power to the input and desired output voltage. The combined design and energy management problem is tackled via a multi-objective optimization supported by a design space exploration based on a full factorial parametric analysis. Therefore, a Pareto front is derived by considering the hydrogen consumption and overall hybrid unit mass as objective functions. As additional contributions, the auxiliaries’ power absorption, heat generated by the stack and resulting cooling load are also estimated, thus providing information for the preliminary sizing of the thermal management system. For the mission profile under consideration, the hydrogen consumption exhibited a variation ranging from 7 kg to 6.7 kg as the fuel cell system rated power increased. On the other hand, a smaller fuel cell system lowers the hybrid unit’s total mass. Particularly, when considering a configuration featuring a 70.5 kW fuel cell system, a single stack and two DC-DC converters, the total mass is estimated to be approximately 237 kg. Therefore, for the reduced impact on the aircraft’s maximal mass, the latter design choice is deemed as the most suitable option to be installed on hybrid aircraft with more electric onboard systems.
Aliberti, PaoloSorrentino, MarcoCuomo, FabrizioNapolitano, Ciro
Lin, RuiAdas, Camilo Abduch
While hydrogen is a clean and renewable energy source for fuel cell vehicles, its production involves various costly methods, with steam reforming being the current popular yet environmentally detrimental technique. An alternative approach involves the use of electrochemical devices such as proton exchange membrane water electrolyzers (PEMWE), capable of producing pure hydrogen through renewable energies. Nevertheless, these devices face challenges in improving their performance, with the most challenging aspect found in PEMWE being the anode, where the oxygen evolution reaction (OER) occurs. This poses a bottleneck issue because the generated oxygen does not exist solely in dissolved form but also as a gas. The released oxygen gas tends to combine with water vapor, forming bubbles that obstruct the reaction sites. Therefore, this study aims to enhance PEMWE performance by developing an advanced two-dimensional porous electrode model considering heat and mass transport as well as electrochemical reactions. Topology optimization (TO) is then applied to search for optimal material distribution in the anode catalyst layer. The model is developed using COMSOL Multiphysics. The results obtained from the simulation involve a comparison between multi-objective optimization and single-objective optimization. While single-objective optimization focuses solely on the best material distribution for the best performance, multi-objective optimization also considers uniform temperature variation as another objective. The findings from this study are beneficial to those interested in not only high-performance anodes but also anodes that possess durability for long-term operation.
Orncompa, PeerapatPassakornjaras, PhonlakritCharoen-amornkitt, PatcharawatAlizadeh, MehrzadSuzuki, TakahiroTsushima, Shohji
As the automotive sector shifts towards cleaner and more sustainable technologies, fuel cells and batteries have emerged as promising technologies with revolutionary potential. Hydrogen fuel cell vehicles offer faster refueling times, extended driving ranges, and reduced weight and space requirements compared to battery electric vehicles, making them highly appealing for future transportation applications. Despite these advantages, optimizing electrode structures and balancing various transport mechanisms are crucial for improving PEFCs’ performance for widespread commercial viability. Previous research has utilized topology optimization (TO) to identify optimal electrode structures and attempted to establish a connection between entropy generation and topographically optimized structures, aiming to strengthen TO numerical findings with a robust theoretical basis. However, existing studies have often neglected the coupling of transport phenomena. Typically, it is assumed that a single force corresponds to a specific flux, such as a temperature gradient for heat transfer (following Fourier’s law) or a concentration gradient for mass transport (following Fick’s law). From a non-equilibrium thermodynamics (NET) perspective, multiple forces contribute to fluxes in electrochemical systems. This study aims to explore the local and global entropy generation of topographically optimized porous reactors in reaction-diffusion systems, considering the coupling effects between heat and mass transport. The results reveal a tree-like structure as the optimized design for porous reactors. This heterogeneous structure exhibits minimal global scaled entropy generation and the most uniform local scaled entropy generation. Furthermore, the study distinguishes and discusses entropy generation from different mechanisms.
Tep, Rotanak Visal SokLong, MenglyAlizadeh, MehrzadCharoen-amornkitt, PatcharawatSuzuki, TakahiroTsushima, Shohji
Fuel cell vehicles (FCVs) offer a promising solution for achieving environmentally friendly transportation and improving fuel economy. The energy management strategy (EMS), as a critical technology for FCVs, faces significant challenges of achieving a balanced coordination among the fuel economy, power battery life, and durability of fuel cell across diverse environments. To address these challenges, a learning-based EMS for fuel cell city buses considering power source degradation is proposed. First, a fuel cell degradation model and a power battery aging model from the literature are presented. Then, based on the deep Q-network (DQN), four factors are incorporated into the reward function, including comprehensive hydrogen consumption, fuel cell performance degradation, power battery life degradation, and battery state of charge deviation. The simulation results show that compared to the dynamic programming–based EMS (DP-EMS), the proposed EMS improves the fuel cell durability while approaching the control effectiveness of DP global optimization. In comparison to the back-propagation-based EMS (BP-EMS), the proposed EMS obtains a 0.37% reduction in the equivalent hydrogen consumption and a 4.72% increase in effective Ah-throughput; the fuel cell performance degradation reduces by 40.09%, balancing the degradation of fuel cell and power battery while ensuring low energy consumption and improving the overall performance of the system. Finally, the adaptability of the proposed strategy to driving conditions is validated in this article.
Song, DafengYan, JinxingZeng, XiaohuaZhang, Yunhe
This study evaluates the performance of alternative powertrains for Class 8 heavy-duty trucks under various real-world driving conditions, cargo loads, and operating ranges. Energy consumption, greenhouse gas emissions, and the Levelized Cost of Driving (LCOD) were assessed for different powertrain technologies in 2024, 2035, and 2050, considering anticipated technological advancements. The analysis employed simulation models that accurately reflect vehicle dynamics, powertrain components, and energy storage systems, leveraging real-world driving data. An integrated simulation workflow was implemented using Argonne National Laboratory's POLARIS, SVTrip, Autonomie, and TechScape software. Additionally, a sensitivity analysis was performed to assess how fluctuations in energy and fuel costs impact the cost-effectiveness of various powertrain options. By 2035, battery electric trucks (BEVs) demonstrate strong cost competitiveness in the 0-250 mile and 250-500 mile ranges, especially when primarily charged at depots. Fuel cell electric vehicles (FCEVs) remain competitive in the 250-500-mile range, particularly under higher diesel prices. For distances over 500 miles, FCEVs become the preferred solution, providing greater range and operational flexibility. By 2050, technological advancements and reduced truck costs further enhance the feasibility of both BEVs and FCEVs. The BEV500 shows improved efficiency and resilience to energy price fluctuations, making it viable for medium-range operations and cost-effective even with high en-route electricity rates. FCEVs are expected to remain competitive in both medium and long-range operations, especially when diesel prices are elevated, positioning them as strong alternatives to conventional powertrains for long-haul routes.
Mansour, CharbelBou Gebrael, JulienKancharla, AmarendraFreyermuth, VincentIslam, Ehsan SabriVijayagopal, RamSahin, OlcayZuniga, NataliaNieto Prada, DanielaAlhajjar, MichelRousseau, AymericBorhan, HoseinaliEl Ganaoui-Mourlan, Ouafae
Fuel cell electric vehicles (FCEVs) are gaining increasing interest due to contributions to zero emissions and carbon neutrality. Thermal management of FCEVs is essential for fuel cell lifespan and vehicle driving performance, but there is a lack of specialized thermal balance test standards for FCEVs. Considering differences in heat generating mechanism between FCEVs and internal combustion engine vehicles (ICEVs), current thermal balance method for ICEVs should be amended to suit for FCHVs. This study discussed thermal balance performance of ICEV and FCHVs under various regulated test conditions based on thermal balance tests in wind tunnel of two FCEVs and an ICEV. FCEVs reported overheat risk during low-speed climbing test due to continuous large power output from fuel cell (FC). Frequent power source switches between FC and battery were observed under dual constrains of fuel cell temperature and battery state of charge (SOC). Significant temperature exceedance of ICEV occurred during flameout and soaking test due to heat accumulation after flameout. Duration time to reach thermal balance state for FCEVs was longer than ICEV due to deterioration in thermal exchange efficiency resulted from inconspicuous temperature difference between FC and coolant. Several modifications including extended test duration time and integration of test conditions were proposed to develop thermal balance test condition sequence for FCEVs. Graded verification system was recommended to comprehensively judge thermal management performance of FCEVs. Such proposal was expected to support the formulation of FCEVs thermal balance test standard and guide improvements of vehicle thermal management performance.
Fang, YanhuaMin, YihangMing, ChenLi, HongtaoLi, DongshengHe, ChongMao, Zhifei
The transportation sector is responsible for a significant portion of greenhouse gas emissions. Within the sector, truck freight is responsible for a third of the associated emissions. Alternative powertrains are seen as a viable approach to significantly reduce these emissions. Prior to making a large-scale transition, it is important to consider the following questions: will the power grid support a transition to alternative powertrains?; will the transition truly reduce carbon emissions?; and will the transition impose an unnecessary economic burden on companies within the industry? The answer to these questions, however, can vary by geography, maturity/capacity of the energy distribution network or predicted vehicle load. We focus on the latter two questions, investigating the variation in estimated total cost of ownership and carbon emissions across the United States at the zip code level for both heavy-duty battery electric vehicles and heavy-duty fuel cell electric vehicles. As a benchmark, we compare estimated emissions and costs of alternative powertrain vehicles to that of conventional heavy-duty vehicles powered by diesel internal combustion engines. This work highlights areas with electric grids primed for a transition to alternative powertrain vehicles, such as the Pacific Northwest, and areas that require further infrastructure investment in renewables, such as many of the Mountain states, Missouri, and Florida. Additionally, this work illustrates the current advantages in carbon emissions of battery electric vehicles compared to fuel-cell electric vehicles, while providing insights into required regional investments for narrowing the gap.
Goulet, NathanSun, RuixiaoFan, JunchuanSujan, VivekMiller, Brandon
This paper aims to model and simulate a design specification for a fuel cell electric powertrain tailored for Extreme H motorsport applications. A comprehensive numerical model of the powertrain was constructed using GT-SUITE v2024, integrating the 2025 Extreme H regulations, which include specifications for the fuel cell stack, electric motors, hydrogen storage, and battery systems. A detailed drive cycle representing the real-world driving patterns of Extreme E vehicles was developed, utilizing kinematic parameters derived from literature and real-world data. The performance of the Extreme H powertrain was benchmarked against the Toyota Mirai fuel cell vehicle to validate the simulation accuracy under the same racing conditions. The proposed design delivers a maximum power output of 400 kW, with 75 kW supplied by the fuel cell and 325 kW by the battery, ensuring optimal performance within the constraints set by the Extreme H 2025 regulations. Additionally, the design maintains an optimal fuel cell operating temperature of 81°C, as indicated in the literature. The logical methodology employed for developing the powertrain, which includes integrating regulations, designing the drive cycle, and optimizing the performance envelope, is elaborated in this paper.
Moreno Medina, JavierSamuel, Stephen
In addition to electric vehicles (EVs), hydrogen fuel cell systems are gaining attention as energy-efficient propulsion options. However, designing fuel cell vehicles presents unique challenges, particularly in terms of storage systems for heavy hydrogen tanks. These challenges impact factors such as NVH (noise, vibration, and harshness) and safety performance. This study presents a topology optimization study for Hydrogen Energy Storage System (HESS) tank structure in Class 5 trucks, with a focus on enhancing the modal frequencies. The study considers a specific truck configuration with a HESS structure located behind the crew cab, consisting of two horizontally stacked hydrogen tanks and two tanks attached on both sides of the frame. The optimization process aimed to meet the modal targets of this hydrogen tank structure in the fore-aft (X) and lateral (Y) directions, while considering other load cases such as a simplified representation of GST (global static torsion), simplified side impact, and angled impact. By utilizing solid and shell elements, as well as Frequency Response Function (FRF) analysis, various load paths and configurations were explored to identify efficient designs that meet the modal targets and structural requirements. The optimized structure was verified and translated into a feasible and manufacturable design.
Yoo, Dong YeonChavare, SudeepViswanathan, SankarMouyianis, Adam
With the growing energy crisis, people urgently need green energy sources to replace fossil ones. As a zero-emission clean energy source, the proton-exchange membrane fuel cell (PEMFC) has received growing attention from researchers due to its broad practical application. However, the large-scale application of PEMFC is currently impeded by their unsatisfying power output and high cost. PEMFC is composed of multiple components, among which the catalyst layer significantly affects the output power and cost of PEMFC. Drastically reducing the amount of platinum in the catalyst layer can bring great benefits to PEMFC, yet causing the large voltage loss associated with enlarged local oxygen molecule transport. Cutting down the platinum content in the catalyst layer can yield substantial cost savings for PEMFC. Developing an efficient catalyst possessing enhanced oxygen reduction reaction (ORR) catalytic performance is conducive to the commercialization of low-Pt proton exchange membrane fuel cells. In this work, a carbon catalyst substrate with a high nitrogen content was synthesized and Pt-Co alloy nanoparticles were deposited and annealed to form Pt-Co and Co-N-C dual active sites. The obtained Pt-Co/PDA-CS deliver an extraordinary performance, achieving a half-wave potential of 0.907 V and a mass activity of 0.375 A/mgPt.
Liu, YuchenLiu, XinCai, XinDu, AiminLin, Rui
Polymer Electrolyte Membrane Fuel Cells (PEMFCs) recently received a relevant interest as an electric power generation technology in Fuel Cells Electric Vehicles (FCEVs) to decarbonize hard-to-abate sectors as a complement to Battery Electric Vehicles (BEVs). However, the massive requirements of power and durability indicate the urgent need to develop higher-than-ever power density designs with minimum internal gradients to mitigate degradation, discarding sub-optimal designs since the early design stage. Starting from the outcomes of a first study, confirming that for industry-relevant PEMFCs the parallel channel flow field was the only archetype able to minimize jointly pressure losses and limiting super-saturation at high current density, still several degrees of freedom exist for the cell designer. In this study, the research of the optimal PEMFC design is fine-tuned using a CAE-guided design process. Candidate solutions are explored using an optimization software and solving for the coupled mass/heat/charges transport processes in PEMFCs. The study aims at identifying the designs maximizing the current density and/or the membrane water content. The investigated input variables are the width of the bipolar plate ribs and the thickness of the gas diffusion layers, evaluated independently at cathodic and anodic side. The methodology shown in this paper leverages the versatility of parametrized 3D-CAD models and of multi-dimensional 3D-CFD simulation and it is applied to an elementary cell unit, albeit being easily scalable to more complex geometries. Starting from a conventional baseline design, two optimized configurations are identified that maximize the current density under the same voltage (+10%) and the uniformity of the membrane water content (+13%), respectively, showing the entity of performance gain made possible by the wise use of optimization methods in the field of PEMFC engineering.
Rossi, EdoardoCroci, FedericoMartoccia, LorenzoCicalese, GiuseppeD'Adamo, Alessandro
Due to advantages such as high efficiency, low emissions, and fuel flexibility, solid oxide fuel cells (SOFCs) have garnered significant attention as promising power sources for automotive applications. Nickel/yttria-stabilized zirconia (Ni/YSZ) is one of the most widely used anode materials in SOFCs, as it can catalyze both chemical and electrochemical reactions of carbon-containing fuels. However, the direct use of carbon-containing fuels can lead to carbon deposition on the Ni/YSZ anode, negatively impacting the performance and reliability of automotive SOFC systems. The diffusion of carbon atoms within nickel plays a crucial role in the carbon deposition process and requires further investigation. The oxygen atoms that spillover from YSZ also participate in main reactions such as carbon deposition and electrochemical reactions in Ni. Molecular dynamics (MD) is one of the main methods for studying atomic diffusion in crystalline structures. In this study, reactive force field molecular dynamics (ReaxFF-MD) models of Ni and Ni/YSZ crystal structures are established. The operating temperature of automotive SOFCs is typically 500-700°C, which results in a low frequency of diffusion events in the ReaxFF-MD model, leading to high computational costs. Therefore, an acceleration technique known as collective variable-driven hyperdynamics (CVHD) is employed to extend the time scale of the simulations. The diffusion coefficient of carbon atoms in nickel at low temperatures is calculated. Additionally, the spillover process of oxygen atoms in YSZ is considered, and the diffusion coefficients of oxygen atoms in both Ni and YSZ are calculated. The Arrhenius equation parameters for carbon and oxygen diffusion in nickel are determined, laying the foundation for further studies on the mechanisms of carbon deposition and oxidation on Ni/YSZ anode materials.
Du, HaoyuZhang, KaiqiXiao, MaZhang, XiaoqingShuai, Shijin
The depletion of fossil fuels and the emergence of global warming propel public sectors to explore alternative energy such as renewable electricity and hydrogen to reduce greenhouse gas (GHG) emissions. Numerous studies have demonstrated substantial environmental benefits of electric light-duty vehicles. However, research focusing on heavy-duty vehicles is still relatively scarce, and the transition to zero emissions heavy-duty trucks is facing enormous technical and economic challenges. This work investigated GHG emissions during the manufacturing and assembly phase of heavy-duty vehicles (HDVs), including battery electric trucks (BETs) and gaseous hydrogen fuel cell electric trucks (FCETs) using SimaPro software package with wildly accepted Ecoinvent database based on UK grid mix scenarios. A comparative analysis of greenhouse gas (GHG) emissions during the production phase of 700 bar- and 350 bar-H2 FCETs and their battery electric counterparts (eqBETs) was conducted under two UK electricity grid mix scenarios: current and 2050 future electricity grid mixes. The baseline vehicles are 19500 kg H2 fuel cell electric rigid truck (350 bar H2) and 37195 kg H2 fuel cell electric articulated truck (700 bar H2). In the context of the current UK grid mix, the results indicated that the production of the 19.5 tons 350 bar-H2 FCET accounted for unit emissions (per ton of vehicle weight) of 4306.09 kg CO2_eq/t, while 700 bar-H2 FCET (37.195 tons) had emissions of 3868.17 kg CO2_eq/t. By contrast, the 700 bar-eqBET exhibited unit GHG emissions of 7314.98 kg CO2_eq/t, while 350 bar-eqBET showed slightly higher emissions of 7396.06 kg CO2_eq/t. Additionally, the 700 bar-H2 FCET demonstrated more promising performance in reducing production related GHG emissions compared to other truck scenarios under the future electricity grid mix.
Zhao, JianboLi, HuBabaie, MeisamLi, Kang
Diverse solutions will likely be needed to decarbonize the commercial truck sector in the United States. Battery-powered vehicles play a predominant role but in some cases, fuel cell trucks are more advantageous for the consumer. This study examines several medium- and heavy-duty applications designed for different driving range requirements to identify the design space where battery and fuel cell trucks are attractive. Also considered are the impacts of purchase price, fuel cost, and vehicle usage. We examine the top 10 truck classes as well as bus applications based on vehicle population, fuel usage, and driving distances. We assume a 2030 scenario where both batteries and FC systems become less costly and more efficient, as targeted by the U.S. Department of Energy. Even for smaller-class vehicles, where battery electric vehicles are expected to be the most economical among clean vehicle solutions, the results are not straightforward. Based on vehicle design, usage, and external operating conditions, some scenarios exist in which fuel cell-based powertrains are necessary to meet consumer needs. In heavier vehicles with long-range operational requirements, fuel cell-powered trucks are already seen as the leading contender to diesel. This work also quantifies the impact of new powertrain weight on cargo carrying capacity, and the need for additional downtime for recharging or refueling. These estimates could potentially guide future technological development to ameliorate the detrimental impact of these factors by guiding future cost reduction targets for these technologies to ensure competitiveness.
Vijayagopal, RamBirky, Alicia
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