Browse Topic: Hydrogen engines

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Investigation of Combustion Dilution Strategies on Performance and Emissions of a Single-Cylinder Spark-Ignition Direct-Injection Hydrogen Engine2026-37-0009To be published on 06/09/2026
Hydrogen internal combustion engines research is particularly relevant for propulsion systems requiring long range and fast refuelling while offering advantages in fuel purity requirements and operational efficiency. Leveraging the existing engine industry offers the potential for a fast response in the reduction of greenhouse gas emissions. However, abnormal combustion and high NOx emissions limit the feasibility of stoichiometric operation in hydrogen engines, making the evaluation and optimisation of dilution strategies essential. While lean combustion has been widely studied, the impact of exhaust gas recirculation (EGR), particularly in combination with lean mixtures, has yet to be comprehensively assessed. This study investigates the effectiveness of different dilution strategies, with a specific focus on the combined effects of air dilution and EGR on hydrogen combustion. Their joint influence on thermal efficiency, combustion stability, and emissions is evaluated across a range
King, Aidan, Islam, Reza, Pickering, Simon, Yuan, Hao, Mudge, Henry, Giles, Karl, Goyal, Harsh, Jones, Peter, Akehurst, Sam, Esposito, Stefania
Effect of Ar mass ratio and mixture equivalence ratio on the integrated hydrogen argon power cycle2026-37-0012To be published on 06/09/2026
This paper investigates hydrogen combustion in an argon–oxygen (Ar–O₂) environment for compression ignition engine applications using computational fluid dynamics (CFD). The numerical framework is validated through two independent datasets: experimental results from Sandia National Laboratories and hydrogen jet ignition experiments conducted in an Ar–O₂ atmosphere, establishing confidence in the predictive capability of the model. A parametric analysis is performed to evaluate the effects of excess air ratio (λ) and argon mass fraction on ignition characteristics, combustion efficiency, and engine performance. The results indicate that operating under lean conditions improves combustion efficiency but leads to a substantial reduction in engine load. Increasing the argon mass ratio enhances engine thermal efficiency, primarily due to the higher specific heat ratio of argon, which improves the thermodynamic efficiency of the cycle. However, elevated argon concentrations significantly
Chitsaz, Iman, Ahammed, Sajid, Kakoee PhD, Alireza, Salahi, Mohammad Mahdi, Andwari, Amin, Ahmad, Zeeshan, Hyvonen, Jari, Mikulski, Maciej
Predictive Modelling of NOx and Unburned Hydrogen Emissions in a Direct-Injection Hydrogen SI Engine2026-37-0007To be published on 06/09/2026
Hydrogen is emerging as a compelling energy carrier for future transportation due to its potential to enable fully decarbonised operation and near-zero tailpipe pollutant emissions. Realising this potential in reciprocating internal combustion engines requires a detailed understanding of the complex interactions governing hydrogen combustion and emissions formation. In this context, physics-based emission predictive modelling offers a powerful means to accelerate the development and optimisation of hydrogen-fuelled engines by enabling rapid evaluation of operating strategies without the need for extensive experimental campaigns. This study investigates the simulation of pollutant emissions from a 0.5L single-cylinder research engine equipped with side-mounted direct hydrogen injection and spark ignition. The work focuses on the development and assessment of predictive models for nitrogen oxides (NOx) and unburned hydrogen (uH₂) emissions within a 1D–0D simulation framework. For NOx
Malfi, Enrica, De Felice, Massimiliano, Esposito, Stefania, Ribnishki, Aleksandar, King, Aidan, Akehurst, Sam, Jones, Peter, Goyal, Harsh
Emission and Combustion Characteristics of a Hydrogen Direct-Injection Spark Ignition Engine Using EGR2026-01-03254/7/2026
This study experimentally investigates the combined effects of exhaust gas recirculation (EGR) and injection timing on the combustion and emission characteristics of a hydrogen direct injection engine. A single-cylinder 395 cc research engine was used, with injection timing varied from 60° to 180° BTDC and EGR rates from 0% to 30%. In-cylinder pressure, apparent heat release rate (AHRR), NOx, and unburned hydrogen concentrations were measured to analyze the influence of mixture formation and dilution on engine performance. Under non-EGR conditions, retarding the injection timing promoted mixture stratification, resulting in faster flame propagation and shorter combustion duration. However, localized high-temperature regions increased NOx formation, while incomplete combustion in lean or rich zones elevated unburned hydrogen emissions. When EGR was introduced, both ignition delay and combustion duration increased due to reduced oxygen concentration and thermal dilution. Nevertheless
Yang, Heetae, Ki, Youngmin, Kim, Jungho Justin, Kim, Jinsu, Bae, Choongsik, Hwang, Joonsik
Characterisation of Particle Number and Size from a DI SI Engine Operating on Hydrogen versus Gasoline: Operating Sensitivities and Filtration Effects2026-01-03784/7/2026
Hydrogen Internal Combustion Engines (H₂ICEs) offer the potential for near-zero carbon emissions. However, while nitrogen oxide (NOₓ) emissions have been extensively studied, particulate emissions, specifically particle number (PN), which are widely attributed to in the literature to lubricant oil pyrolysis and exacerbated by hydrogen’s short quenching distance, remain less well understood. This study investigates exhaust-gas particle emission characteristics from a spark-ignition, single-cylinder research engine based on MAHLE Powertrain’s downsizing engine combustion system. The work was carried out at Brunel University of London and compares gasoline and hydrogen direct-injection strategies (central versus side injection) across a wide range of operating conditions, including variations in engine speed, load, air–fuel ratio (λ), rail pressure, and spark timing. While previous studies have investigated hydrogen particle formation mechanisms under isolated operating conditions, the
Harrington, Anthony, Zaman, Zayne, Nickolaus, Chris, Zhao, Hua, Wang, Xinyan, Hall, Jonathan
Physics-Based Simulation for Sustainable Fuels Part 2.1: Inter-Ring Pressure Measurements and 2D/3D Ring Dynamics Analysis across Multiple Engine Platforms – Light Vehicle2026-01-02814/7/2026
The growing demand for sustainable mobility and transportation is accelerating the adoption of alternative fuels, particularly hydrogen, in internal combustion engines. The first part of this publication series highlights the significance of 2D simulation as a crucial and computationally efficient tool for the precise development of hydrogen Power Cylinder Units. This approach demonstrates predictive capability proofed through engine tests, achieving a reduction in lube oil consumption by 5 g/h during high-load operations, alongside a 28% decrease in blow-by and an 11% reduction in hydrogen flow to the crankcase. To provide deeper insights into the complexities identified in Part 1, this study employs inter-ring pressure measurements across various engine types and configurations, including light vehicles, heavy-duty trucks, and large-bore applications, covering a broad range of engine displacements from 2 to almost 100 liters. This investigation in Part 2.1 focuses on understanding
Moreira, Rui, Köser, Philipp, Rösch, Hannes, Ehnis, Holger
CFD-Guided DoE-ML Optimization Methods in a Heavy-Duty Hydrogen Engine2026-01-03264/7/2026
This study introduces a CFD-guided design of experiments (DoE) and machine learning (ML) framework for the co-optimization of piston and pre-chamber geometries in a passive pre-chamber heavy-duty hydrogen engine operating at medium and low loads. Starting from a reference configuration, an omega-type piston and a methane-optimized pre-chamber, the design space was parameterized using seven geometric variables. A Sobol sequence was employed to generate 96 randomized design variants in the DoE, each evaluated through high-fidelity 3D-CFD simulations to capture key combustion and performance metrics. The resulting dataset served as the foundation for developing and evaluating several ML regression models. A rigorous ML workflow was adopted, featuring 5-fold cross-validation and hyperparameter tuning via Bayesian optimization to ensure generalization and robustness. Model selection was based on multi-metric performance criteria including prediction accuracy, error stability, and
Menaca, Rafael, Shakeel, Mohammad Raghib, Liu, Xinlei, Mohan, Balaji, AlRamadan, Abdullah, Cenker, Emre, Silva, Mickael, Zhang, Anqi, Pei, Yuanjiang, Im, Hong
Effects of the Spark Location and Timing in a Heavy-Duty Hydrogen-Fueled Engine2026-01-03314/7/2026
The use of hydrogen in internal combustion engines offers a promising route to lower-carbon propulsion in heavy-duty transportation. However, its distinct combustion characteristics as high flame speed, wide flammability limits, and susceptibility to abnormal combustion, necessitate careful engine and ignition system design. This study numerically investigates the combined effects of spark plug (SP) location and ignition timing on the performance of a heavy-duty diesel engine converted to spark-ignition and operated with hydrogen as fuel at reduced compression ratio. The numerical study aims to guide engine design. Three-dimensional computational fluid dynamics simulations with detailed hydrogen chemistry were conducted to evaluate flame development, and relevant combustion metrics under different loads. Model validation against engine combustion data and hydrogen injection from a low-pressure, high-mass-flow direct injector are also presented. The results demonstrate that SP placement
Menaca, Rafael, Shakeel, Mohammad Raghib, Panithasan, Mebin, Liu, Xinlei, Qahtani, Yasser, AlRamadan, Abdullah, Cenker, Emre, Silva, Mickael, Pei, Yuanjiang, Turner, James, Im, Hong
CuSCR Catalysts Under H 2 -ICE Exhaust Gas Conditions2026-01-03614/7/2026
In the near to mid-term, hydrogen internal combustion engines (H2-ICE) can be a bridge technology for reducing carbon emissions. A few challenges anticipated under lean-burn H2-ICE operation are the significant drop in turbo-out temperatures, combined with higher water content, and the possible presence of unburned hydrogen in the exhaust, which could have a potential impact on performance and durability of the downstream exhaust aftertreatment system, particularly oxidation and SCR catalysts, as these conditions can suppress low-temperature oxidation activity, perturb Cu-site speciation and redox cycling in SCR catalysts, and exacerbate hydrothermal aging under sustained wet operation. This study examines the impact of excess water and residual hydrogen on Cu-SCR durability, active site chemistry, and stability for the case with and without an upstream oxidation catalyst, through aging tests at 450 °C and 550 °C. Changes in Cu redox cycles were assessed through site quantification
Kim, Mi-Young, Daya, Rohil, Kamasamudram, Krishna
Investigation of CDI and TCI Ignition Characteristics for Lean Hydrogen-Air Mixtures in a Constant Volume Combustion Chamber2026-01-03274/7/2026
The discharge characteristics of ignition systems critically influence flame kernel formation and ignition stability under lean-burn conditions. This study experimentally compares a transistor coil ignition (TCI) and a capacitor discharge ignition (CDI) system in a constant-volume combustion chamber using hydrogen–air mixtures. The electrical behavior of both systems was first characterized through synchronized measurements of voltage, current, and high-speed imaging under various operating conditions with a resistive spark plug. The CDI system exhibited high-current (≈750 mA), short-duration (≈250 μs) discharges with strong instantaneous power but limited total spark-gap energy (≈5 mJ), while the TCI system produced lower-current, longer-duration (≈3 ms) discharges with higher cumulative energy (≈30 mJ). Flow-field tests revealed that the TCI discharge duration and energy release were strongly influenced by airflow, whereas CDI discharge behavior remained largely unchanged at flow
Cong, Binghao, Jin, Long, Yu, Xiao, Zhou, Qing, Tjong, Jimi, Zheng, Ming
Heavy Duty Hydrogen Internal Combustion Engine Emissions Development to Achieve Ultra-low NOx2026-01-03564/7/2026
This paper presents the emissions development of a heavy-duty hydrogen internal-combustion engine (H₂ICE) targeting ultra-low NOx with a design goal of 20 mg/hp-hr. The approach integrates advanced thermal management of the engine and aftertreatment, including engine out NOx management through air-fuel ratio controls and an electric heater to accelerate catalyst light-off and sustain activity at low-load/idle conditions. A diesel-derived aftertreatment system (ATS) is selected to maximize practicality and component commonality, and an integrated controls strategy spanning the engine and ATS is implemented to demonstrate ultra-low NOx capability over EPA certification cycles. The paper concludes with considerations for periodic SCR regeneration to ensure emission compliance.
Shakya, Bijesh, Xu, Hui, Yang, Zhao, Stetter, John
Physics-Based Simulation for Sustainable Fuels Part 2.2: Inter-Ring Pressure Measurements and 2D/3D Ring Dynamics Analysis across Multiple Engine Platforms – Heavy Duty and Large Bore2026-01-02804/7/2026
The growing demand for sustainable mobility and transportation is accelerating the adoption of alternative fuels, particularly hydrogen, in internal combustion engines. The first part of this publication series highlights the significance of 2D simulation as a crucial and computationally efficient tool for the precise development of hydrogen Power Cylinder Units. This approach demonstrates predictive capability proofed through engine tests, achieving a reduction in lube oil consumption by 5 g/h during high-load operations, alongside a 28% decrease in blow-by and an 11% reduction in hydrogen flow to the crankcase. To provide deeper insights into the complexities identified in Part 1, this study employs inter-ring pressure measurements across various engine types and configurations, including light vehicles, heavy-duty trucks, and large-bore applications, covering a broad range of engine displacements from 2 to almost 100 liters. Part 2.1 focuses on understanding the cyclic variations
Köser, Philipp, Moreira, Rui
Advanced Multifunctional Catalysts for Emission Control in Hydrogen and Diesel Engines2026-01-03674/7/2026
As hydrogen internal combustion engines (H2-ICE) gain traction, optimizing exhaust aftertreatment technologies for nitrogen oxide (NOx) control has become increasingly critical. While selective catalytic reduction (SCR) systems remain the primary approach for NOx mitigation, oxidation catalysts are also being explored to facilitate hydrogen oxidation and improve overall exhaust treatment efficiency. This work presents a multifunctional catalyst (MFC) concept that combines supported Pd and Cu-zeolite to enable simultaneous NOx reduction and hydrogen oxidation within a single catalytic unit. Preliminary results show that hydrogen oxidation on supported Pd occurs above 300 °C, while Cu-zeolite achieves nearly complete NOx conversion. Experiments on individual components indicate that supported Pd initiates ammonia oxidation only after hydrogen is depleted. In the presence of hydrogen, ammonia conversion remains below 20%, indicating that hydrogen availability suppresses ammonia oxidation
Danghyan, Vardan, Becker, Jan Martin, Hünnekes, Edgar, Patchett, Joseph
Model-Based Development of a Heavy-Duty H 2 -ICE and Integrated, Turbogeneration, Electrification, and Supercharging (ITES) System2026-01-04264/7/2026
Changing global economic conditions and efforts to reduce greenhouse gas emissions are driving the need to develop efficient, near-term, alternative propulsion system technologies for heavy-duty vehicles. This study combines a hydrogen internal combustion engine (H2-ICE) with electrically assisted turbocharging, exhaust energy recovery, and mild hybridization to maximize propulsion system efficiency and reduce NOx emissions. To reduce cost and packaging impact of integration of these technologies on an engine, the study presents a model-based development and optimization of an Integrated Turbogeneration, Electrification, and Supercharging (ITES) system that combines the enabling components into a single compact unit. In the first phase of this study, a H2-ICE and aftertreatment concept for a MY2027 7.7L medium heavy-duty on-road engine was developed and evaluated through 1D simulation. The concept was to convert a diesel engine by changing the cylinder head to implement a port fuel
Bustamante, Oscar, Correia Garcia, Bruno, Joshi, Satyum, Franke, Michael
Physics-Based Simulation for Sustainable Fuels Part 1: Simulation-Driven Hydrogen Engine Power Cylinder Unit Optimization and Experimental Confirmation2026-01-02784/7/2026
The demand for sustainable mobility and transportation is accelerating the adoption of alternative fuels, particularly hydrogen, in internal combustion engines. However, these engines present specific risks, such as flammable crankcase gas accumulation from blow-by and irregular combustion resulting from oil transport into the combustion chamber. Addressing these challenges requires advanced simulation tools to optimize power-cylinder-unit performance, specifically piston ring and gas dynamics. This study demonstrates the success of physics-based 2D simulation for hydrogen PCU design optimization, focusing on blow-by reduction and control of gas-flow-driven oil transport. Unlike commercial codes with adjustment and fitting parameters, the 2D simulation code – developed by Massachusetts Institute of Technology and successfully applied by MAHLE over decades – is fundamentally physics-based, enabling direct predictive capability without empirical calibration. Leveraging the validated
Köser, Philipp, Moreira, Rui, Deuß, Thomas, Morgado, Leonardo
Experimental Study on the Effect of Ignition Strategy on Combustion and Emissions in a Direct Injection Hydrogen Engine2026-01-03304/7/2026
Hydrogen-fueled internal combustion engines (H₂ICEs) are a promising pathway toward carbon-neutral transportation, but their efficiency and emissions performance are highly sensitive to ignition control strategies. This study systematically investigates the combined effects of spark timing (−10 to −26 °CA BTDC) and spark energy (25–40 mJ) on combustion characteristics in a direct injection H₂ICE operating at a constant speed of 1400 r/min under low, medium, and high load conditions. Results show that spark timing advance produces load-dependent effects: at low load, it increases the peak heat release rate while delaying peak pressure and shortening combustion duration; at medium and high loads, it advances both peaks toward TDC with an optimal spark timing shifting closer to −14 °CA. Ignition delay was only slightly reduced at low load but significantly shortened by about 3 °CA at high load. NOx emissions increased nearly linearly with spark advance, while slight retardation
Zhao, Keqin, Lou, Diming, Zhang, Yunhua, Fang, Liang, Tan, Piqiang, Hu, Zhiyuan
Experimental Study of Entrainment by Hydrogen-Like Impinging Jets of Various Types in a Confined Compartment03-19-01-00062/9/2026
Recent literature has highlighted significant heat transfer losses and elevated particle formation in direct-injection hydrogen engines, particularly when compared to hydrocarbon fuels such as methane. These challenges are attributed to hydrogen’s unique physicochemical properties, notably its short flame quenching distance and high diffusivity, as well as the interaction between the hydrogen jet and lubricated cylinder surfaces, which promotes lubricant entrainment into the combustion chamber. Consequently, a fundamental understanding of these entrainment mechanisms is a prerequisite for developing engineering strategies to enhance thermal efficiency and mitigate particle formation. The reported study investigates gaseous jet–air interaction in a confined volume to elucidate the influence of injector geometry on jet propagation and air entrainment. Three distinct jet configurations were examined: the wide hollow-cone, the narrow hollow-cone, and the round jets. The jet evolution and
Ben David Holtzer, Ben Binyamin, Tartakovsky, Leonid
Increasing the Efficiency of Hydrogen Direct Injection Internal Combustion Engines through the Use of Miller Cycles and Water Injection03-19-01-00011/31/2026
Hydrogen-fueled reciprocating engines typically feature reasonable efficiencies and low engine-out emissions but low power density, compromising their utility and economics. Previous hydrogen engine research has found efficiency and anti-knock benefits when using either Miller cycles or water injection. This article therefore studies, for the first time, a directly injected (DI), spark-ignited, heavy-duty, turbocharged and hydrogen-fueled engine operated with both Miller cycles and water injection. Miller cycles, with either early or late intake valve closure, and water injection combine to achieve high engine efficiencies approaching 50%, which is significantly higher than the same engine with standard valve timing. The increased susceptibility of hydrogen autoignition in these Miller cycles is overcome by water injection, which simultaneously increases the charge density, counteracting both lean-burn hydrogen’s and Miller cycles’ commonly observed power loss. This demonstrates that
Mortimer, Joel, Poursadegh, Farzad, Brear, Michael, Yang, Yi
Total Cost of Ownership Analysis of Fuel Cell and Hydrogen-Powered Commercial Vehicles for Cost Competitiveness with ICE and BEV2026-26-02541/16/2026
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
Jacob, Joe, Chougule, Abhijeet
Optimizing Hydrogen Engine Performance a Comparative Study of Lean & Stoichiometric Calibration Approach2026-26-02611/16/2026
Hydrogen combustion in internal combustion engines offers numerous advantages, such as zero CO2 emissions and high flame speed, which make it a promising alternative fuel for green vehicle solutions. In order to maximize the engine performance with hydrogen, however, meticulous calibration of the air-fuel mixture must be performed, particularly when lean and stoichiometric combustion conditions are considered. Lean burning, i.e., excess air, offers better thermal efficiency and lower NOx emissions but can cause lower engine power and combustion instability. Stoichiometric combustion, however, ensures complete combustion of the fuel-air mixture, but at the cost of higher combustion temperatures and consequently, high NOx emissions. Calibration strategies for hydrogen engines are presented in this paper by comparing the lean and stoichiometric strategies and their implications on engine power output, efficiency, and emissions. Test data from several hydrogen engine configurations
Jadhav, Ajinkya, Bandyopadhyay, Debjyoti, Sutar, Prasanna S, Sonawane, Shailesh Balkrishna, Rairikar, Sandeep D, Thipse, Sukrut S
Experimental Evaluation of Energy and Exergy of Hydrogen, CNG and Gasoline Fuelled High-Speed Spark Ignition Engine2026-26-02581/16/2026
The maximum power is recorded with Gasoline than CNG and Hydrogen fuel. The maximum exergy and energy efficiency is with Hydrogen, followed by CNG and then Gasoline. Hydrogen fuel has a maximum potential to convert into energy. The maximum energy destruction of 48.7kW for gasoline fuel at 3000 rpm and followed by CNG and hydrogen. The maximum entropy generation of 85.5 W/K with Gasoline and 60.72 W/K and 29.39W/K for CNG and hydrogen engine respectively at 10000 rpm. The entropy generation rate increase with engine speed. The highest rate of heat release is from hydrogen fuel, followed by Gasoline and CNG.
Shinde, Apurwa Balasaheb, Kadam, Tushar, karunamurthy, K, SHINDE, DR BALU
Comprehensive Engine Testing Methodologies for Hydrogen Internal Combustion Engine Validation with Combustion & Performance Evaluation Techniques2026-26-02561/16/2026
Validation of hydrogen-fuelled internal combustion engine (H2 ICE) is critical to assess its feasibility as sustainable transportation with zero carbon emissions. This experimental analysis conducted on Ashok Leyland’s 6cylinder 2V engine to evaluate the engine performance & durability with hydrogen fuel. Combustion behaviour of hydrogen ICE needs to be closely monitored during continuous operation of validation testing, due to its unique properties compared to other conventional fuels. During engine run, a pre-ignition source can cause knock event leading to instant failure of critical parts like piston assembly, spark plug, liner, valves & cylinder head. Also, hotspots inside IMF leads to backfire affecting the air intake & fuel injection assembly. This study emphasizes the significance of precise instrumentation of thermocouples across engine on cylinder head, intake manifold & exhaust manifold, to detect performance detoriation and combustion abnormalities causing knocking
Vasudevan, Sindhuja, J, Narayana Reddy, Bolar, Yogesh Ganesh, Pandey, Sunil, N, Harish, N R, Varatharaj, Karthikeyan, K, Kumar D, Kishore
Establishing a High-Pressure Direct Injection Hydrogen Engine Test Facility with Integrated Ammonia Fuel Capability: Technical Considerations, Safety Framework, and Best Practices2026-26-02671/16/2026
The transition toward zero-carbon propulsion technologies has highlighted the urgent need for specialized test infrastructure to support hydrogen and alternative fuel research. This paper presents the conceptualization, design, and operation of a High-Pressure Direct Injection (HPDI) Hydrogen Internal Combustion Engine (H2 ICE) test facility with integrated ammonia fuel testing capability, marking a significant advancement in India’s sustainable automotive research efforts. Drawing from practical experience, it outlines crucial technical specifications, safety protocols, and best practices for establishing robust, adaptable, and secure testing environments. Addressing the industry’s need for dedicated infrastructure, it is engineered for adaptability across various engine types including heavy-duty, light-duty, and multi-utility vehicles while aligning with global technical standards. Key technical considerations include a transient dynamometer with an advanced automation system for
Dhyani, Vipin, Kurien, Caneon, Subramanian, Balaji, Khandai, Chinmayananda, Muralidharan, M
Performance and Emission Characteristics of a Lean-Boosted Direct Injection Hydrogen Combustion System for Retrofitting Heavy Duty Diesel Engines2026-26-02681/16/2026
To address the imperative for decarbonizing the heavy-duty transport sector and advancing sustainable energy solutions, this paper presents a novel lean-boosted Direct Injection (DI) Hydrogen Internal Combustion Engine (H2 ICE) combustion system. This system is developed to retrofit existing flat-deck Diesel engines, offering a viable pathway towards drastically reduced emissions. Building on consolidated expertise from prior production-oriented Port Fuel Injection H2 engine development (DUMAREY 6.6ℓ V8), this research focuses on leveraging the distinct advantages of DI for hydrogen. An experimental assessment, supported by 1D and 3D-CFD analyses, demonstrates the system's capability to achieve highly efficient operation in Spark Ignition (SI) mode under ultra-lean and EGR-diluted conditions. The study confirms the elimination of combustion anomalies such as backfiring, pre-ignition, and knock, while achieving ultra-low engine-out NOx emissions and near-zero CO2, HC, CO, and PM. The
Gessaroli, Davide, Golisano, Roberto, Pesce, Francesco, Boretto, Gianmarco, Accurso, Francesco
3D CFD Simulation Methodology for Safe and Efficient Hydrogen Refueling for Hydrogen Internal Combustion Engines2026-26-02521/16/2026
As conventional fossil fuels are on the verge of depletion, the demand of alternative fuel has intensified. Among these, Hydrogen offers higher energy output per unit weight compared to conventional fuels, high octane number, and compatibility with Internal combustion engines (ICE). However, the volatility of hydrogen (H2) presents challenges, particularly during the refueling process, where uncontrolled temperature rise occurs because of negative Joule-Thomson (JT) effect. This brings an alarming bell for the safety of fueling stations, vehicles, and mankind. This paper investigates the physics involved in hydrogen tank filling, focusing on maintaining the hydrogen gas temperature below 85 °C during the process. A 3D Computational Fluid Dynamics (CFD) analysis was performed to model the temperature and pressure behavior of hydrogen during filling. The study provides insights into the optimal fill rates, temperature distribution, and the evolution of peak temperature locations inside
Khanna, Gourav, Veerbhadra, Swati, Sahu, Abhay Kumar
Comparitive Study of Hydrogen Internal Combustion Engine Performance for Port Fuel Injected and Direct Injected Technology Routes using 1D Simulation2026-26-02501/16/2026
Hydrogen Internal Combustion Engine (HICE) has the promise of zero carbon solution for the mobility industry. The key beneficiary would be the medium and heavy-duty segment of transportation which are likely to adapt the battery electric or fuel cell electric solution in longer term. This particular segment of engines need high low end torque, peak torque and rated power which cannot be compromised. Additionally, a competitive thermal efficiency w.r.t diesel engines would be advantageous. Direct Injection (DI) of hydrogen gives higher specific power and thermal efficiency as compared to Port Fuel Injection (PFI). This study focuses on the performance characteristics of these technology routes to aid in the HICE development process. Current work involves the use of 1-D thermodynamic simulation using GT-SUITE for modeling the performance of HICE. Both predictive and non-predictive methodologies of modeling the combustion were employed. Initially, the model validation of the PFI engine
Parthiban R, Varun, Karthikeyan, K R, Narayana Reddy, J, Paramasivam, Prakash, Manjunath, M, Kumar D, Kishore, N R, Varatharaj, Suresh, K, G, Yogesh Bolar, Sadagopan, Krishnan, Pandey, Sunil Kumar
Design Optimization of the Vanity Cover for H 2 Concentration Management2026-26-02631/16/2026
The integration of hydrogen (H2) as a fuel source in internal combustion engines (ICE) necessitates stringent design measures to mitigate leakage risks and ensure operational safety. This study focuses on the design optimization of vanity cover for hydrogen engines. Computational fluid dynamics (CFD) analysis is carried out to assess and control hydrogen leakage through fuel rail connections, injector interfaces and associated high pressure fuel system components. Detailed modelling of hydrogen flow behavior, diffusion characteristics of leaked hydrogen are simulated for worst case scenarios. Design iterations targeted improvement in ventilation pathways, strategic placement of vent holes, and internal flow management to minimize localized hydrogen buildup. The final design achieved hydrogen concentration, which was less than 4%. This paper validates the critical role of CFD driven design methodology in proactively identifying leakage risks and optimizing component geometries for
Veerbhadra, Swati Ashvinkumar, Sahu, Abhay Kumar, Singh, Rahul
Analysis of Indian Patent Landscape on Alternative Fuels with a Focus on Hydrogen Fuel Cells and Hydrogen Internal Combustion Engines2026-26-02621/16/2026
This paper presents an analysis of the Indian patent landscape concerning alternative fuels, with a specific focus on hydrogen fuel cells and hydrogen internal combustion engines (H2 ICEs). The study aims to provide insights into the innovation trends, key players, white spaces and technological advancements, in this evolving sector within the Indian context. The study is based on the granted patents and disclosures in the said area, and also focuses on the key problems and solutions. Based on a review of patent publications from January 2024 to March 2025, it was observed that a significant number of patent records pertain to the broader domain of hydrogen internal combustion engine disclosures. Specifically, 540 extended families patent publications were screened focusing on hydrogen internal combustion engine as a domain of disclosure. Further analysis revealed that greater 75 % of applicants were from the industry sector, indicating a strong commercial interest in these
Nikam, Mahesh Suresh, Sutavane, Ila, V, Ajay, Aghav, Yogesh
Computational Study of Hydrogen based SCR Technology as an Alternative to Urea SCR in Hydrogen Fueled Engine2026-26-02131/16/2026
Air pollution from vehicle exhaust emissions is a growing issue in major cities around the world. Hydrogen is a clean and carbon-free fuel that presents a promising alternative to the fossil fuels. However, despite its environmental advantages, hydrogen internal combustion engines still produce some nitrogen oxides as a by-product due to high combustion temperatures. This study investigates the effectiveness of current exhaust after-treatment technologies designed to reduce NOx emissions in hydrogen-powered engines. A comparative analysis is conducted between the conventional urea-based selective catalytic reduction used in diesel engines and emerging hydrogen-based selective catalytic reduction technologies for hydrogen engines. The analysis is performed using CFD simulation in ANSYS Fluent, focusing on NOx reduction efficiency and other operational parameters. The results provide valuable insights into the feasibility and effectiveness of hydrogen SCR in achieving reduced NOx
Kashyap, Keshav, Khandagale, Anup, Petale, Mahendra
Controls Solutions for Commercial Hydrogen Engines2026-26-01121/16/2026
India’s commitment to carbon neutrality is significantly shaping the future architecture of commercial vehicle powertrains. While the use of CO₂-free technologies such as battery-electric drivetrains has already been successfully demonstrated across various applications, challenges related to limited range and the lack of high-power charging infrastructure continue to hinder widespread adoption, particularly for productivity-critical commercial vehicles. This has shifted the spotlight toward sustainable fuels, which offer the advantage of fast refueling times. Among these, hydrogen internal combustion engines (H₂ ICE) have gained increasing attention in recent years. In regions such as the European Union, the primary motivation for hydrogen is CO₂ reduction. In contrast, for markets like India, hydrogen also presents a strategic opportunity for reducing dependency on fossil fuel imports. Over the past four years, multiple performance and emission development projects across various H
Arnberger, Anton, Danninger, Alois, Mannsberger, Stefan, Breitegger, Bernhard
Artificial Neural Network-Based Performance and Emission Prediction for Hydrogen-Combustion Multicylinder Engines2025-36-023712/18/2025
In response to the pressing need to reduce greenhouse gas emissions from the transportation sector, hydrogen-fueled internal combustion engines (H2ICEs) have emerged as a promising alternative to conventional fossil-fueled powertrains. However, optimizing H2ICEs presents challenges in balancing performance with emissions, particularly in nitrogen oxide (NOx) formation This study proposes a data-driven methodology using an artificial neural network (ANN) to predict key emission and performance metrics: NOx emissions, brake mean effective pressure (BMEP), brake specific fuel consumption (BSFC), brake power, and brake thermal efficiency, based solely on engine operational parameters. Experimental data were collected from a three-cylinder Ford EcoBoost engine under varying conditions of intake pressure, spark timing, air-fuel ratio, engine speed, and valve timing. Feature selection was performed using the Spearman correlation coefficient, identifying engine speed, start of injection angle
Pasa, Bruno Roberto, Silveira, Juliano Pereira, Fagundez, Jean Lucca Souza, Lanzanova, Thompson Diórdinis Metzka, Martins, Mario Eduardo Santos, Salau, Nina Paula Gonçalves
Impact of Hydrogen Electrification on Transmission Systems for Heavy-Duty Vehicles2025-36-017812/18/2025
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
Biêng, Ethan Lê Quang, Pontes, Guilherme Ayroso, Conrado, Guilherme Barreto Rollemberg, Lopes, Elias Dias Rossi, Rodrigues, Gustavo Simão
Investigation of Active Pre-Chamber Ignition on an Optically Accessible Ultra-Lean DI Hydrogen Engine2025-01-052411/25/2025
Hydrogen is a promising alternative to conventional fuels for decarbonizing the commercial vehicle sector due to its carbon-free nature. This study investigates the ignition and flame propagation characteristics of hydrogen in a 2-liter single-cylinder optical research engine representative of the commercial vehicle sector. The main objective was to enable high power density operation while minimizing NOx emissions. For that, ultra-lean combustion was employed to lower in-cylinder temperatures, addressing the challenge of NOx formation. To counteract delayed and unstable combustion under lean conditions, an active pre-chamber ignition system was implemented. It uses a gas-purged pre-chamber with separate hydrogen injection and spark plug ignition. Turbulent hot gas jets from the pre-chamber ignite the fresh mixture in the main combustion chamber, enabling faster and more stable ignition compared to conventional spark plugs. Additionally, the low volumetric energy density of hydrogen
Borken, Philipp, Bill, Daniel, Link, Lukas, Dinkelacker, Friedrich, Hansen, Hauke
Evaluation of Advanced Powertrain Technologies for Large Agricultural Tractors: Insights on Energy Consumption and Life Cycle Environmental Impact13-06-03-002511/21/2025
This study aims to assess how alternative electrified powertrain technologies affect energy use for agricultural tractors in the Autonomie simulation tool. The goal of this study is also to assess the feasibility and performance of hydrogen internal combustion engines as a suitable alternative for the agricultural tractor powertrains. The energy consumption and efficiencies of alternative powertrains and fuel options are analyzed and compared across a variety of duty cycles using modeling and simulation methodologies. The considered alternative powertrains are series, parallel, power-split hybrid electric, fuel cell, and battery electric powertrains. The alternative fuel and powertrains are evaluated for their energy efficiency as well as their potential to reduce greenhouse gas emissions and improve overall tractor performance in a variety of agricultural applications. Following a methodology developed by Argonne National Laboratory and Aramco Americas, the study applied prospective
Kim, Namdoo, Yan, Ziming, Vijayagopal, Ram, Jung, Jaekwang, He, Xin
Advanced Multi-Fidelity Simulation of Piston Oil Jet Cooling in High-Performance Engines2025-32-008111/3/2025
The development of next-generation hydrogen-fueled engines introduces critical challenges related to thermal loads within the combustion chamber, particularly in high-performance applications. To address the extreme temperatures encountered, effective piston cooling strategies, such as oil jet impingement, are essential. Accurately predicting thermal stresses to prevent component failure is therefore crucial. However, numerical simulations often come with significant computational costs. This paper presents a comprehensive multi-fidelity modeling approach to predict the thermal behavior of pistons under these demanding conditions. The model integrates a simplified 3D thermal representation of the piston, a lumped-parameter mechanical model of the piston-liner assembly, and convective boundary conditions obtained at various levels of fidelity, from high-level Computational Fluid Dynamics (CFD) simulations to literature correlations. Additionally, the study examines the influence of
Sassoli, Andrea, Romani, Luca, Ferrara, Giovanni, Paolicelli, Giovanni, Balduzzi, Francesco
Clarification of the Mechanism of Abnormal Combustion in Hydrogen Engines -Investigation of Abnormal Combustion Location by Visualization Measurement-2025-32-006411/3/2025
Hydrogen internal combustion engines present a promising path towards carbon neutrality, yet their development is challenged by abnormal combustion phenomena like backfire and pre-ignition. These phenomena limit engine torque and reduce component reliability. This study is aimed to elucidate the mechanisms behind these phenomena in hydrogen internal combustion engines. We utilized a multi-cylinder engine with optical access for direct high-speed imaging of in-cylinder processes to visualize backfire and pre-ignition. Initial analysis, combining visualization data with one-dimensional (1D) simulations, indicated that high temperatures of the ground electrode of the spark plug could be a key trigger factor for abnormal combustion. To investigate this hypothesis, the surface temperature of the ground electrode was measured under firing conditions using a two-color thermometry system. The measurements revealed that the electrode temperature exceeded the compressed gas temperature near Top
Muramatsu, Keiji, Tokuhara, Satoshi, Kadu, Pravin, Yoshimura, Kei, Nakama, Kenjiro
Analysis of Flame Propagation Characteristics in a Hydrogen Engine using an Optically Accessible Engine2025-32-006111/3/2025
This study focused on the effects of hydrogen on the flame propagation characteristics and combustion characteristics of a small spark-ignition engine. The combustion flame in the cylinder was observed using a side-valve engine that allowed optical access. The fundamental characteristics of hydrogen combustion were investigated based on combustion images photographed in the cylinder with a high-speed camera and measured cylinder pressure waveforms. Experiments were conducted under various ignition timings and equivalence ratios and comparisons were made with the characteristics of an existing hydrocarbon liquid fuel. The hydrogen flame was successfully photographed, although it has been regarded as being difficult to visualize, thus enabling calculation of the flame propagation speed. As a result, it was found that the flame propagation speed of hydrogen was much faster than that of the existing hydrocarbon fuel. On the other hand, it was difficult to photograph the hydrogen flame
Arai, Yuto, Ueno, Takamori, Suda, Ryosuke, Sato, Ryoichi, Nakao, Yoshinori, Ninomiya, Yoshinari, Matsushita, Koichiro, Kamio, Tomohiko, Iijima, Akira
A Study of Knocking Characteristics in a Hydrogen SI Engine under High Compression Ratio2025-32-006311/3/2025
This study investigated the knocking characteristics of a hydrogen spark ignition engine for the purpose of increasing efficiency and expanding the operating range. In recent years, research focused on carbon neutrality has been vigorously conducted, and hydrogen has attracted attention as a next-generation fuel for internal combustion engines (ICEs). The combustion characteristics of hydrogen are vastly from those of existing gasoline. It is essential to have a sufficient understanding of the combustion characteristics of hydrogen in order to develop next-generation ICEs designed to operate on hydrogen fuel. There are especially many aspects of the knocking mechanisms of hydrogen that are unclear. Consequently, those characteristics and mechanisms must be clarified for the purpose of expanding the operating range of hydrogen engines and enhancing their efficiency. In this study, experiments were conducted using a single-cylinder hydrogen engine that was operated at a high compression
Ishihara, Hiromasa, Kishibata, Shunsuke, Miyake, Shota, Iida, Tomoya, Kuwabara, Kenta, Yoshihara, Shintaro, Miyamoto, Sekai, Iijima, Akira
Experimental Study of hCNG on Single Cylinder 395cc Spark Ignition Engine for Performance and Exhaust Emission2025-32-005011/3/2025
There is growing demand for energy utilization due to stricter environmental emission norms to reduce greenhouse gases and other threats posed due to the emissions are major motivation factors for researchers to adopt on strategic plans to decrease the usage of energy and reduce the carbon contents of fuels, the usage of hydrogen or blend of hydrogen with CNG as a fuel in internal combustion engines is the best option. As hydrogen has lower volumetric energy density and higher combustion temperature, pure hydrogen-fueled engines produce lower power output and much higher NOx emissions than gasoline-fueled engine at stoichiometric air-fuel ratio. Blending of hydrogen with CNG provides a blended gas termed as hydrogen-enriched natural gas (hCNG). hCNG stands for hydrogen enriched compressed natural gas and it combines the advantages of both hydrogen and methane. The addition of Hydrogen to CNG has potential to even lower the CNG emissions and is the first step towards promotion of a
Syed, Kaleemuddin, Chaudhari, Sandip, Khairnar, Girish, Sajjan lng, Suresh
Effect of In-Cylinder Hydrogen Mixture Formation on Hydrogen Combustion2025-32-006511/3/2025
Global efforts to mitigate climate change include ambitious long-term strategies by countries to achieve net-zero greenhouse gas emissions by 2050. The automotive sector is exploring carbon-free powertrains, with hydrogen emerging as a key technology. Its zero-emission potential positions it for widespread adoption in power generation, transportation, and industry. Hydrogen engines, particularly direct injection engines offering high power and efficiency, are gaining traction due to their adaptability using existing engine components. However, in a hydrogen direct injection engine, achieving proper mixing of hydrogen and air in the cylinder is challenging, making in-cylinder mixture formation a crucial factor for ensuring stable combustion. To predict hydrogen mixture formation in the cylinder, we conducted a Schlieren visualization experiment of the hydrogen jet. Based on the results, a detailed hydrogen jet model for the direct injection injector was developed. This model was then
Hisano, Atsushi, Saitou, Masahito, Sakurai, Yota, Ichi, Satoaki
Development of the Hydrogen Fueled Internal Combustion Engine for Off-Road Applications2025-32-006611/3/2025
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
Shiraishi, Kentaro, Kishi, Shinji, Kato, Daichi, Mitamura, Kenta, Murakami, Kei, Mikuni, Yusuke
Transient Helium Jet Evolution Using High Speed Schlieren Imaging2025-32-005711/3/2025
The accelerating global shift towards decarbonised energy systems has positioned hydrogen as a highly promising carbon-free fuel. This study comprehensively investigates the macroscopic characteristics and temporal evolution of vortex ring trailing helium jets, serving as a surrogate for hydrogen, injected into a quiescent ambient environment using high-speed Schlieren imaging. This research addresses critical insights into fuel-air mixing dynamics essential for optimising hydrogen direct injection (DI) internal combustion engines. Analysis of helium jet tip’s topology revealed a three-stage evolution from an initial pressure-insensitive phase, dominated by pressure wave structures, to a momentum-driven, vortex-dependent growth stage, then to a fully developed stage. Specifically, the lower-pressure cases showed increased Kelvin-Helmholtz instability and distinct head vortex pinch-off at the final stage. Jet tip velocities transitioned from initial high, rapid pressure wave development
Dong, Shuo, Shi, Hao, Zhang, Gengxin, Feng, Yizhuo, Lu, Enshen, Wang, Xinyan, Zhao, Hua
Thermal Management in Electrified Transportation: A Comparative Study of Different Powertrain Technologies2025-28-041210/30/2025
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
K, Neelima, K, Anisha, Ch, Kavya, C, Somasundar, Satyam, Satyam, P, Geetha
Impact of Oil Composition on Pre-Ignition in a Hydrogen Engine04-18-03-001810/10/2025
Pre-ignition (PI) is a common issue in internal combustion engines (ICE) with spark ignition. While the various causes have been identified with conventional fuels (such as gasoline or gasoline blends), the causes with hydrogen in ICE are not yet fully understood. This article presents the results of investigations into the influence of seven different lubricating oils on PI in a single-cylinder hydrogen research engine. The variation of two different parameters at two engine speeds were investigated: load and air/fuel mixture. For both variations, the tests start at the same conditions and run until the operating limit of the engine is reached (peak firing pressure, or maximum intake manifold pressure). The PI and knocking PI are investigated, while classifying them according to the peak cylinder pressure. It has been observed that enleanment above λ = 2.4 can lead to higher PI rates, while simultaneously reducing the knocking PI. During the load sweep at 2000 1/min, the highest
Pehlivanlar, Benjamin, Torkler, Michael, Fischer, Marcus, Göbel, Christoph, Pischinger, Stefan, Maulbetsch, Theo, Nübling, Fritz, Neumann, Stephan
Approaches for Mechanical Development and Validation of Hydrogen Internal Combustion Engines2025-01-039810/7/2025
Hydrogen Internal Combustion Engines (H2 ICEs) are seen as a viable zero-emission technology that can be implemented relatively quickly and cost-effectively by automotive manufacturers. The changed boundary conditions of a hydrogen-fueled engine in terms of mechanical and thermal aspects require a review and potential refinement of the design especially for the 'piston bore interface' (liner honing, ring and piston design) but also for other engine sub-systems, e.g. the crankcase ventilation system. The influence of oil entry into the combustion chamber is even more important in hydrogen engines due to the risk of oil-induced pre-ignition. Therefore, investigations of the interaction between friction, blowby and oil transfer into the combustion chamber were performed and are presented in this paper. During the investigations, experimental tests were carried out on a single-cylinder engine ('floating liner') and on a multi-cylinder engine. The 'floating liner' concept allows the crank
Plettenberg, Mirko, Gell, Johannes, Grabner, Peter, Gschiel, Kevin, Hick, Hannes
Developing Custom Engine Test and Solutions for Handling Water in Lubricants for Hydrogen Internal Combustion Engines2025-01-040010/7/2025
Hydrogen internal combustion engines (H2–ICEs) are being evaluated as a potential pathway for lowering the CO2 emissions intensity of the transportation and the power generation sectors as well as off-road applications such as agriculture and construction industry. H2–ICEs offer several advantages to the Original Equipment Manufacturers (OEMs); such as retaining the existing engine architecture and hardware, whilst achieving a lower emissions intensity than diesel engines. Some of the key challenges for the H2–ICEs operation are managing excessive amounts of water build-up in the oil under certain operating conditions and pre-ignition which have significant impact on the engine life and durability. In the current study, the authors developed a custom test cycle using a 7.4-litre 6-cylinder turbo-charged hydrogen engine designed for combined heat and power applications. The test cycle was created with the purpose of accumulating significant amounts of water (hydration phase) in the oil
Bansal, Dinesh, Weimar, Hans-Joachim, Berlet, Peter
CFD and FE Toolset for Predicting Structural Temperatures in a Hydrogen Internal Combustion Engine2025-01-038310/7/2025
Hydrogen has been identified as a promising decarbonization fuel in internal combustion engine (ICE) applications in many areas including heavy-duty on- and off-road, power-generation, marine, etc. Hydrogen ICEs can achieve high power density and very low tailpipe emissions. However, there are challenges; designing systems for a gaseous fuel with its own specific mixing, burn rate and combustion control needs, which can differ from legacy products. Being able to determine the thermal distribution and temperatures of the power cylinder components has always been critical to the design and development of ICE. SAE-2023-01-1675 [1] presented an analytical FE-based tool, and validation using both FE and CFD methods for a Euro VI HD Diesel engine converted to operate on hydrogen gas using direct injection. In this study, updated methods and investigations are presented for Hydrogen ICE including applicability of the Woschni heat transfer correlation, use of CFD thermal wall functions and a
Bell, David J., Shapiro, Evgeniy, Turquand d Auzay, Charles, Hernandez, Ignacio, Hynous, Jan, Kohutka, Jiri, Osborne, Richard, Penning, Richard, Tomiska, Zbynek
Condensate Formation in Exhaust Systems during Cold Start2025-24-00819/7/2025
In order to minimize tailpipe emissions of vehicles with combustion engines, highest conversion rates of exhaust gas aftertreatment systems are indispensable. At low ambient temperatures, gaseous emissions increase due to inhomogeneous mixture formation and incomplete combustion. Simultaneously, formation of condensate on exhaust gas-carrying components is stimulated due to temperatures dropping below the dew point. The acidic condensates contain more than 95 vol.-% water and a small fraction of aliphatic and aromatic hydrocarbons. In acidic environments these hydrocarbons can be polymerized, forming insoluble deposits that become progressively less reactive with time. These deposits may harm components of exhaust systems by fouling. As low temperature conditions are particularly promoting condensate formation, the aim of this study is to investigate condensate formation and composition during cold start and early warm-up phases in the exhaust duct of state-of-the-art internal
Knapp, Sebastian, Hagen, Fabian P., Wagner, Uwe, Bockhorn, Henning, Trimis, Dimosthenis, Koch, Thomas
Waste Heat Recovery in Hydrogen Fueled Internal Combustion Engines2025-24-01089/7/2025
Waste Heat Recovery is one of the most investigated and promising technologies for energy efficiency in the transportation sector. It consents to maintain the high-level technology of the present propulsion systems, based on Internal Combustion Engines, while increasing the overall engine and vehicle system efficiency. At the same time, the use of alternative fuels, like hydrogen, has the same crucial role to reduce harmful and greenhouse emissions, without overturn the existing mature technology. A hydrogen-fueled Internal Combustion Engine is proposed in this paper, equipped with waste heat recovery consisting in an additional radial turbine downstream the turbocharger of the engine (Turbo-Compound). The aim is to have a reduction of the specific consumption in most of the operating points of the engine, considering the effect of the recovery and the engine equilibrium rearrangement. The use of hydrogen increases recoverable enthalpy at the engine exhaust, which is intended to be
Di Battista, Davide, Cipollone, Roberto, Corti, Enrico, Brancaleoni, Pier Paolo, Di Prospero, Federico, Ravaglioli, Vittorio
A Computational Study of Hydrogen Mixing and Combustion in a High-Speed Direct-Injection Spark-Ignition Engine2025-24-00049/7/2025
Hydrogen has emerged as a promising alternative fuel due to its potential to enable clean and sustainable energy systems. Direct injection is the preferred fueling strategy for hydrogen engines, as it enhances power density while addressing safety concerns. However, the low density of hydrogen necessitates a large molar quantity of fuel, leading to strong fuel-air stratification and posing challenges for mixing in a confined chamber with complex turbulent flow and jet/wall interactions. This challenge is exacerbated in the present study, where the evaluated high-performance engine operates at a high engine load (indicated mean effective pressure of about 20 bar) and an extremely high speed (7500 revolutions per minute). Furthermore, to target high efficiencies, restrict abnormal combustion behaviors and inhibit oxides of nitrogen emissions, a lean-burn combustion strategy with a global equivalence ratio of 0.4 was applied, where diffusive-thermal (DT) instability effects would matter
Menaca, Rafael, Liu, Xinlei, Mortellaro, Fabio, Medda, Massimo, Im, Hong G.
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