The aviation industry contributes to around 2% of global carbon dioxide emissions. As various sectors of the economy look to reduce their global carbon footprint, the aviation industry is positively acknowledging alternatives to jet fuel. Hydrogen proves to be one such alternative having a high energy density and producing zero carbon emissions on combustion. Hydrogen when used in a jet engine produces water vapour and NOx emissions. In order to reduce the effect of GHGs, the current study aims to develop aircraft concepts suitable with hydrogen propulsion through fuel cells for a short-haul commercial mission profile. Aircrafts such as Metro-23 and Dornier 228-212 were referenced for the requirements of a utility turboprop aircraft. The weight estimation was done to obtain the take-off weight of 10,863 kg following the optimization of thrust to weight ratio and wing loading to calculate the initial dimensions. OpenVSP was used to model the initial structure of the aircraft. For the

Bhattacharya, Anisha, Seetha Ramu, Sree Valli, C N, Lakshmi Manasa, Rohit, Benjamin

Weight Estimation of Novel Aircraft Configurations in Early Design Phase

2026-26-0773

To be published on 06/01/2026

Initial weight estimation from Top Level Aircraft Requirements (TLAR) is a critical first step in aircraft design, yet existing empirical methods are inadequate for novel configurations such as those using Liquid Hydrogen (LH2) or Sustainable Aviation Fuels (SAF). This paper presents a hybrid methodology for top-level weight estimation of such unconventional aircraft. The approach is based on modifying a conventional baseline aircraft, integrating a new statistical model with component-specific weight estimations. A multivariate regression model to estimate the empty weight fraction (We/W0) was developed from a dataset of 44 conventional aircraft, yielding an R-squared value of 0.833. This statistical model was integrated with physics-based models for novel components, including cryogenic fuel tanks and fuel systems. The methodology accounts for iterative changes to fuselage structure and parasitic drag. Four configurations were analyzed: fuel types being Jet A1, SAF, LH2 with aft

Goyal, Tushar

Effect of Pre-Chamber Geometry on Methanol Cold-Start Combustion in an SI Engine

2026-01-0307

4/7/2026

Vehicle pollutant emissions are a major challenge in the development of internal combustion engines. To meet increasingly strict regulations, the automotive sector is exploring alternative fuels and lean-burn strategies. Methanol is gaining importance as a carbon-neutral fuel due to advances in green production technologies. Methanol, despite its potential for renewable production, faces severe limitations due to its inherent poor cold-start performance with conventional ignition systems. In this context, the present study aims to investigate the influence of pre-chamber ignition on cold-start combustion by using high-speed optical diagnostics to visualize flame propagation while simultaneously measuring in-cylinder pressure and engine performance. A major result concerns the significant cyclic variability of conventional spark ignition (SI) under cold-start conditions, which exhibits significant cyclic variability. Instead, passive pre-chamber ignition significantly enhances cold

Sementa, Paolo, Altieri, Nunzio, Tornatore, Cinzia

Ambient and Initial Temperature Effects on Battery Electric Vehicle (BEV) Range and Energy Consumption Rate Modeled in FASTSim

2026-01-0277

4/7/2026

Ambient and initial temperatures significantly impact the energy consumption rate (ECR) of battery electric vehicles (BEVs) due to auxiliary loads and the temperature dependence of battery efficiency. This study introduces a streamlined, physics-based thermal modeling approach within the FASTSim tool that bridges the gap between oversimplified constant-load models and computationally expensive high-fidelity simulations. By employing a lumped thermal mass framework, the model captures fundamental energy balances and critical non-linear energy penalties while maintaining the computational efficiency required for expansive sensitivity studies. The simulations evaluated a compact BEV hatchback with a resistive heater over city (UDDS) and highway (HWFET) test cycles. Compared to a 22°C initial and ambient temperature baseline, a -7°C initial/ambient temperature resulted in a 221% increase in the ECR for the city cycle and a 100% increase for the highway cycle. Conversely, a 45°C initial

Baker, Chad, Steuteville, Robin, Holden, Jake, Gonder, Jeffrey, Carow, Kyle

Effect of Liquidized-Gas Fluid Properties in a High-Pressure Fuel Pump

2026-01-0273

4/7/2026

Paper considers the effects of fluid properties from liquified gases during high pressure pumping, at ranges from 200 to 1500 bar, and at speeds of 500 to 1500 rpm. Tests represent highest to date pressure ranges attained with liquified fluids such as DME. The paper examines the effects of compressibility on the pumping and resulting loading torque characteristics described over the pumping cycle as resolved by a high-fidelity sensor. Experimental tests and simulated performance based on a 1-D model are compared for Diesel and DME for a high-pressure fuel pump, piston style, featuring two plunger-barrels. Each of the pump’s plunger-barrel is inlet metered electronically, allowing the pump to run at a variable displacement and with the flexibility to deactivate one or both plungers fully. The model captures the response of the inlet metering valve and output valve lifts across speed and loads. The output check valve is subject to pressure pulsations and shows the importance to optimize

de Ojeda, William, Wu, Simon (Haibao)

The Influence of Split Injection Ratio on Efficiency and NO _x Emissions in a Pilot Diesel-Ignited Hydrogen Direct Injection Engine

2026-01-0329

4/7/2026

This study investigates the impact of the hydrogen split injection ratio on the combustion of pilot diesel-ignited hydrogen direct-injection engines, which is expected to affect hydrogen-air mixture conditions and thus flame propagation and diffusion flame developments. Experiments were conducted on a 1-litre single-cylinder diesel engine equipped with an additional hydrogen injector operating at 35 MPa. Hydrogen accounting for 95% of total input energy was injected at 150 and 60 °CA bTDC for the first and second pulses, which were selected as high-efficiency injection timings from previous equal-split injection tests. The 5% diesel energy was injected near TDC to control CA50 at 10 °CA aTDC. While varying the split ratio between the two hydrogen injections, in-cylinder pressure/aHRR profiles, engine efficiency/power output and engine-out emissions of NOx and CO2 were evaluated. Results showed that the hydrogen split ratio does not significantly affect IMEP/efficiency, which

Zhao, Yifan, Chan, Qing Nian, Kook, Sanghoon

Experimental Characterisation of Combustion, Performance, and Emissions in a Hydrogen Fueled Opposed Piston Engine

2026-01-0335

4/7/2026

Recent studies have demonstrated that the current Internal Combustion Engine (ICE) can be adapted to operate with hydrogen for the decarbonisation of transport and gensets. This is mostly done by conversion of conventional 4-stroke compression ignition diesel engines or spark ignition gas engines for heavy-duty vehicles or 4-stroke spark ignition gasoline engines for light-duty applications. This study aims to assess the adoption of pure hydrogen direct injection technology on a novel two-stroke opposed-piston engine designed by Carnot Engine Ltd. The engine provides a flexible platform that can operate in both compression ignition and spark ignition modes, allowing it to adopt multiple fuels. For the first time, a single cylinder prototype version of this new engine was operated and tested with hydrogen at Brunel University of London. During the engine experiment, a spark ignition timing sweep was carried out at low and mid-loads up to 10 bar IMEP to identify the Minimum ignition

Mohamed, Mohamed, Roeinfard, Nima, Wang, Xinyan, Zhao, Hua, Watts-Farmer, Archie, Rahman, Nadiur, Lempp, Francis

Study of Deposit Control Additive Efficacy in Gasoline Direct Injection Engines

2026-01-0349

4/7/2026

There is an increasing adoption of Direct-Injection Spark-Ignition (DISI) engines in the market, which per 2024 US Environmental Protection Agency (EPA) Automotive Trends Report represents 73% of new vehicles sold in the US. And while it is well accepted that DISI offers advantages over Port Fuel Injection (PFI) technology in meeting stringent CO2 emissions and fuel economy requirements set by the EPA, DISI engines are also associated with increased formation of injector deposits. These deposits may foul injectors and accumulate on the injector tip causing distorted spray patterns and diffusive combustion. Ultimately, this leads to engine performance deterioration and increased harmful emissions. To control deposit formation, detergent-type chemistries are added to the fuel in small amounts. Deposit Control Additives (DCAs) function by preventing the formation of deleterious injector deposits as well as removing existing ones. This study used standardized protocols describing the

Soriano, Nestor, Williams, Rod, Cracknell, Roger, Lang, Wendy, Chahal, Jasprit

Model-Based Development of a Heavy-Duty H ₂ -ICE and Integrated, Turbogeneration, Electrification, and Supercharging (ITES) System

2026-01-0426

4/7/2026

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

Thermal Management of Gasoline Fuel Tanks

2026-01-0114

4/7/2026

This study presents a fully integrated, vehicle-level thermal management model for gasoline fuel tanks, designed to predict transient fuel temperatures, tank wall heating, and vapor generation under real-world driving conditions. The model simulates coupled thermal contributions from exhaust radiation, transient underbody airflow, conductive heat transfer, in-tank pump heating, and dynamic changes in fuel composition and level. Validation against on-road measurements shows strong agreement for fuel temperature and vapor flow profiles. Results confirm that exhaust radiative heating is the dominant thermal load, particularly during the post-shutdown heat soak period. A well-designed heat shield reduced peak tank wall temperature by approximately 27 °C, significantly lowering fuel heating and evaporation. Parametric analysis indicates that while fuel Reid Vapor Pressure (RVP) and tank material influence evaporation, their effect is secondary to external heat mitigation. While this model

El-Sharkawy, Alaa, Asar, Mona, Taha, Nahla, Sheta, Mai

Technical Outlook on the Potential of HVO and Biodiesel Blends for Cleaner Combustion

2026-01-0316

4/7/2026

The increasing need to decarbonize the transport sector is accelerating the adoption of renewable and low-carbon fuels such as Hydrotreated Vegetable Oil (HVO) and biodiesel as sustainable substitutes for fossil diesel. These fuels are evaluated as drop-in solutions requiring no engine recalibration, enabling immediate GHG emission reduction in existing diesel fleets. This study experimentally investigates the combustion, performance, and emission characteristics of a turbocharged common-rail two-cylinder diesel engine (Kohler LWD 442 CRS) operated with conventional fossil Diesel, pure HVO (Hydrotreated Vegetable Oil), and an HVOB20 blend (80% HVO and 20% biodiesel produced from waste cooking oil and animal fats). Tests were carried out under steady-state conditions at the DIIEM Engine Laboratory of Roma Tre University. The analysis focused on in-cylinder pressure evolution, brake power, brake specific fuel consumption (BSFC), and both regulated and unregulated emissions. Regulated

Zaccai, Martina, Chiavola, Ornella, Palmieri, Fulvio, Verdoliva, Francesco

Cradle-To-Grave Assessment of Austrian Passenger Car Traffic based on Actual Vehicle Movements and Derivation of Future Forecasts for Minimising Greenhouse Gas Emissions

2026-01-0457

4/7/2026

As part of the decarbonisation process for passenger car fleet in Austria, battery electric cars in particular have been subsidised in recent years, as these vehicles are considered to be largely emission free during use and are expected to reduce emissions in future. However, in order to sustainably reduce the global greenhouse gas emissions of Austrian passenger car traffic, taking into account all types of fuel systems, it is necessary to apply a cradle-to-grave approach, as is commonly done in comparable analyses in the literature, which evaluates the emissions of the entire vehicle life cycle. The most important phase in the life cycle assessment remains the well-to-wheel phase, which includes emissions from energy supply and vehicle use. Due to the large number of influencing factors, highly simplified models are usually used for this phase in the literature. As part of this work, a methodology was developed that, allows an in-depth analysis of entire vehicle fleets by linking

Lischka, Gregor, Tober, Werner

Numerical Study of Gasoline Direct Injection Sprays at Conditions Relevant to Engine Cold-Start Operation

2026-01-0338

4/7/2026

Gasoline direct injection (GDI) remains a key technology for enhancing engine efficiency and meeting regulated engine-out soot limits, particularly when combined with downsizing and boosted operation. The performance of modern GDI engines strongly depends on the in-cylinder spray process, which governs mixture formation and combustion quality under a wide range of operating conditions. In this context, computational fluid dynamics (CFD) is an effective tool for supporting the design and operation of an engine. However, accurately modeling a spray’s evolution —from early to late injections and across varying ambient conditions —remains a major challenge. This study employs a CFD framework with an optimized spray modeling approach to investigate spray morphology and dynamics under various engine cold conditions. Although all simulations are conducted with a single-injection setup, the early- and late-injection cases are designed to emulate different phases of split-injection operation by

Lien, Hao-Pin (Paul), Torelli, Roberto, Zhao, Le, Park, Ji-Woong, Zhang, Anqi, Pei, Yuanjiang, Hwang, Joonsik, Lee, Kyungwon

CuSCR Catalysts Under H ₂ -ICE Exhaust Gas Conditions

2026-01-0361

4/7/2026

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

Challenges of Mixture Formation in Methanol Port Fuel Injection Engines

2026-01-0337

4/7/2026

Port fuel injection (PFI) is an attractive strategy for methanol adoption in both spark-ignition and dual-fuel compression-ignition engines due to its lower cost and simpler hardware compared to direct-injection. However, methanol PFI mixture formation can be challenging due to methanol’s high heat of vaporization, low volatility at cold conditions and high tendency to wall wetting. Understanding and addressing these challenges is critical to ensure robust engine operation. In this study, the effects of injector geometry, coolant temperature, intake temperature and fueling rate on mixture formation of methanol PFI have been investigated for anhydrous methanol and for a blend of 90%vol methanol plus 10%vol water in an optical engine. Mie scattering and infrared imaging were applied to assess the liquid and vapor methanol distribution in the cylinder. For a high-flow injector compatible with methanol, significant amounts of liquid were detected in the cylinder at all conditions tested

Lee, Sanguk, Narayanan, Abhinandhan

Achieving Euro 7 WHSC NOx Emission Targets from a Spark Ignited Engine Using Methanol-Hydrogen Co-Fuelling

2026-01-0321

4/7/2026

E-methanol is increasingly seen as a promising clean fuel because its chemical makeup is close to fossil fuels, making it easier to use in existing engines. It offers a carbon-neutral option to help reduce greenhouse gases in sectors where cutting emissions is especially difficult, such as transportation. However, while e-methanol avoids adding new carbon dioxide, burning it in internal combustion engines still releases harmful gases like oxides of nitrogen (NOx) and other toxic by-products like formaldehyde and formic acid that damage both health and the environment. This report explores a new strategy that combines methanol with hydrogen to run engines under “ultra-lean” conditions and its impact on emissions, performance and efficiency. Experiments were carried out on a single-cylinder spark ignition engine, with directly injected methanol and port fuelled injection of hydrogen. The findings show that adding about 10% hydrogen (energy basis) at low engine loads can extend the lean

Ambalakatte, Ajith, Geng, Sikai, Cairns, Alasdair, Varaei, Amirata, Harrington, Anthony, Hall, Jonathan, Bassett, Mike, Cracknell, Roger

A Helical Compression Spring Fracture under Impact Velocity in Pump Operation by Theoretical Study and FEA

2026-01-0271

4/7/2026

Helical compression springs have been used widely in various industries from automotive, aerospace and construction to electronics and medical devices. In the automotive industry, they appear in many places such as suspension, valvetrain, etc., as well in the discharge check valve of Gasoline Direct Injection (GDI) pump, which is the subject of study due to a recent fracture in lab testing. A theoretical study is conducted first to establish the equation governing spring dynamic motion under impact velocity, which can be in high magnitude with surging shock wave along spring axis. A new spring shock wave equation is developed for spring axial motion coupled with coil torsional effect. This newly derived shock wave equation has a broader term than the classic spring formula found in most engineering books. In this paper, it shows that the classic spring shock wave equation is only a special case for the general wave equation newly discovered. Then, a theoretical formula on spring shock

Pang, Michael L., Gunturu, Srinu, Norkin, Eugene

Optimal Strategies for SI H2 Combustion System and Pre-Ignition Investigation through Advanced Optical Techniques

2026-01-0324

4/7/2026

The rapidly transforming mobility sector is confronted with a dual challenge: achieving market expansion while significantly reducing emissions. Even if vehicle electrification tends to be favored in developed nations, it is widely acknowledged that no single solution is universally optimal. Within this context, hydrogen emerges as a compelling energy vector. It can be used both in fuel cells and internal combustion engines. This latter benefits from a well-known architecture and existing production infrastructures constituting a viable short-term and cost-effective solution especially for light or heavy-duty and off-road applications. In this context, investigation on the hydrogen spark-ignited internal combustion engine was performed, focusing especially on critical abnormal combustions. Indeed, during early development phase, abnormal combustion management was a challenge requiring the identification of the root cause of these issues. This work, based on the use of a versatile

Londos, Benoit, Bardi, Michele, Serrano, David, Laget, Olivier, Gautrot, Xavier, Bramoullé, Clément, Cordier, Matthieu

A Novel Chemical Clustering Approach for the Acceleration of 3D CFD Simulations of Internal Combustion Engines with Complex Fuels

2026-01-0495

4/7/2026

Detailed kinetics simulations coupled with 3D CFD offer a powerful analysis tool for combustion and emissions. Such methods allow consistent modeling of multi-component fuels from evaporation to combustion and correctly capture the effects of local inhomogeneities created by preferential evaporation on the performance and emissions of modern powertrains. Such computations are extremely computationally demanding, prompting interest in the development of calculation acceleration techniques that can effectively balance the speed and accuracy of the chemical source calculation terms. Chemical kinetics clustering methods are widely used for that effect. However, such techniques must be not only effective but also robust with respect to the engine conditions and fuel composition changes, to reduce the computational demands introduced by the need to calibrate the parameters of the acceleration method itself. In this paper, an extended chemical kinetics clustering approach is proposed. A

Hernandez, Ignacio, Turquand d Auzay, Charles, Shapiro, Evgeniy, Shala, Mehmet, Borg, Anders, Seidel, Lars, Mauss, Fabian

Analysis of In-Cylinder Flow for Hybrid Gasoline Engine using High-Speed Particle Image Velocimetry

2026-01-0298

4/7/2026

To increase the thermal efficiency of a hybrid inline 4-cylinder direct injection engine, combustion promotion was carried out by enhancing the in-cylinder flow. The intake port and piston top shape were optimized using CFD. In-cylinder flow analysis in steady flow showed that the mean steady flow tumble ratio with the in-cylinder flow enhancement specification increased to 1.7 compared to 1.0 with the previous model and 1.4 with the early development specification. The limit engine speed, which is the engine speed at when the mean flow coefficient decreases due to the choke, and the mean steady flow tumble ratio with the in-cylinder flow enhancement specification were positioned on the trade-off line between the NA and the TC engine. In-cylinder flow analysis on the single-cylinder optical engine showed that the in-cylinder flow entering the cylinder smoothly flowed to the exhaust side, and the in-cylinder flow descending on the exhaust side was smoothly converted to the upward flow

Okura, Yasuhiro, Urata, Yasuhiro

Development of an ‘Online’ Combustion System Calibration Method using a Non-Dominated Sorting Genetic Algorithm

2026-01-0285

4/7/2026

Calibration is a major resource bottleneck and source of risk in powertrain technology development. A promising alternative to the typical design-of-experiments (DoE) approach is the use of a ‘Non-Dominated Sorting Genetic Algorithm’ (NSGA) calibration method, where an iterative process is used to directly identify the Pareto Fronts between performance metrics, for example, net mean effective pressure (NMEP) and NOx emission. The goal of the present work was to develop and demonstrate a fully ‘online’ combustion system calibration method based on an NSGA, where the algorithm operates directly on experimental data rather than empirical models as is typical in the literature. This was completed by first designing an optimal NSGA for combustion system calibration and then demonstrating its use for an experimental combustion system calibration on a single cylinder gasoline engine at one operating condition. Results from the design process here indicate that ‘online’ NSGAs have a strong

Mansfield, Andrew

Experimental Study on the Effect of Ignition Strategy on Combustion and Emissions in a Direct Injection Hydrogen Engine

2026-01-0330

4/7/2026

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

In-Situ Raman Measurements of Fuel Dilution of Lubricant Films in a Direct-Injection Spark-Ignition Engine

2026-01-0355

4/7/2026

To measure the fuel proportion within the lubricant film, an in-situ Raman spectroscopy technique was employed in a specially modified single-cylinder direct-injection spark-ignition engine. The engine block was engineered for optical access with a fused silica window, enabling a focused laser beam to probe the lubricant film on the engine liner under motoring conditions. The lubricant used was GTL8 base oil with ZDDP additive, and iso-octane was injected as a model fuel to study fuel-lubricant mixing. A calibration curve was established by recording Raman spectra of known mixtures of GTL8 oil and iso-octane. The Raman intensity ratio of the iso-octane peak to the oil peak was used as a quantitative indicator of fuel concentration. During engine operation, Raman spectra were acquired in real time, on a cycle-by-cycle basis, through the optical window. Upon iso-octane injection, its characteristic Raman peak appeared in the spectrum, and the intensity ratio was referenced against the

Bolle, Bastien, Augoye, Kobi, Wong, Janet, Aleiferis, Pavlos, Hall, Jonathan, Bassett, Mike, Cracknell, Roger

Thesaurus for Fuel System Components

AIR1615B (Current)

3/12/2026

This document provides a summary of names commonly used throughout the industry for aircraft fuel system components. It is a thesaurus intended to aid those not familiar with the lexicon of the industry.

AE-5A Aerospace Fuel, Inerting and Lubrication Sys Committee

How higher-quality gasoline keeps modern engines CLEAN AND EFFICIENT

26AUTP03_03

3/1/2026

Gasoline direct injection (GDI) engines are the most common technology on American roadways in 2025, and soon, an industrywide gasoline quality standard will better reflect their unique operational needs. Here's why that's important. It's no secret that fuel economy has been one of the greatest driving forces of automotive evolution over the past several decades. As corporate average fuel economy (CAFE) standards have grown increasingly lofty, OEMs eke out new efficiencies from every area of the vehicle. One of those areas, of course, is the engine, and many OEMs have deployed gasoline direct injection (GDI) technology, which is becoming the most common engine technology on American roadways. But while GDI engines proliferate, varying fuel additization throughout North America has not necessarily kept pace with their unique needs and can, in fact, hinder those engines from meeting and sustaining their full fuel economy potential.

Blackburn, Brett

Influence of Lubrication Oil on Hydrogen Fuel-Share Combustion in a Conventional Medium-Speed Marine Diesel Engine

2026-01-5014

2/23/2026

Carbon-free fuels present a potential solution for achieving climate-neutral operation of marine engines. However, their availability is minimal at the moment, though a steady increase can be expected in the coming years. During this transition phase, engine concepts that offer conventional diesel operation and a partial blending of alternative fuels to substitute diesel become interesting. This can be achieved, for example, by blending hydrogen in the intake air of a diesel engine, known as hydrogen fuel-share. Due to the high reactivity of hydrogen, its use in engines is limited by abnormal combustion phenomena (e.g., pre-ignition, knocking combustion), which current research on pure gas engines has shown to be strongly promoted by lube oil reactivity. Building on these fundamental investigations, this paper examines the influence of lubricating oil on the combustion characteristics of a H2 fuel-share medium-speed diesel engine and quantifies the potential to increase the hydrogen

Achenbach, Tobias, Meinert, Robert, Mahler, Kay, Kunkel, Christian, Rösler, Sebastian, Prager, Maximilian, Jaensch, Malte

Optimized Design and Economic Evaluation of a Renewable Hydrogen Refueling Station for Public Transport on Elba Island

14-15-01-0004

2/13/2026

The aim of this study is to develop a methodology to significantly reduce emissions in bus fleet renewal scenarios by investigating both technical and economic aspects. This work presents a case study based on Elba Island, Italy, which investigates optimal solutions for replacing existing Diesel buses through a total cost of ownership analysis. The investigation is carried out for four different potential scenarios: renewing the fleet with Diesel buses, renewing the fleet with electric buses, adopting fuel cell buses, and implementing a hybrid solution. The latter represents a synergistic solution that integrates fuel cell buses with the development of a hydrogen refueling station driven by a proton exchange membrane electrolyzer, unlocking the techno-economic potential of self-producing green hydrogen for bus refueling. The novelty of this study is its integrated methodology that combines a total cost of ownership analysis with a tailored design of a green hydrogen production network

Bove, Giovanni, Sorrentino, Marco, Baldinelli, Arianna, Desideri, Umberto

CFD Simulation of Combustion and Emission Characteristics of Pure Spirulina Microalgae Biodiesel in a Single-Cylinder DI Diesel Engine

2026-28-0043

2/12/2026

In this study, the combustion and emission characteristics of a single-cylinder direct injection (DI) diesel engine fueled with Spirulina biodiesel along with diesel blends were examined using a combined CFD and thermodynamic simulation framework. Three test fuels, including pure diesel (D100), Spirulina biodiesel blends (B20 and B40), and pure Spirulina biodiesel (B100), were analysed at 1500 rpm under full load. In the first stage, CFD simulations were performed in ANSYS Fluent, where the Discrete Phase Model (DPM) was applied to capture spray atomization and droplet evaporation, while a non-premixed combustion model coupled with the RNG k-ε turbulence model was employed to resolve in-cylinder flow and heat release dynamics. Subsequently, the Diesel-RK software was utilised to predict engine performance and exhaust emissions based on compression ratios (18.5) and injection timings. Results from the CFD analysis revealed faster atomization and reduced ignition delay for biodiesel

Kumar, B Varun

Enhancing Combustion, Performance and Emission Profiles Using Kapok Methyl Ester Blends with Hydrogen

2026-28-0058

2/12/2026

This study investigates the potential of using a dual green alternative fuel combination, the one is hydrogen fuel and another one is biodiesel for enhancing the Performance, combustion and emission profile of a compression ignition engine. The kapok oil biodiesel was blended with Diesel in proportions of 20% (K20) and 40% (K40) by volume. The hydrogen gas was supplied at a constant flow of 4 liter per minute (LPM). The experimental fuels are neat diesel D100, K20 (80% Diesel and 20 % kapok methyl ester), K40 (60% Diesel + 40 % Kapok methyl ester), K20 + H4L (K20 with 4 LPM hydrogen) and K40+H4L (K40 with 4 LPM hydrogen). These test blends are investigated in a single cylinder direct injection CI engine under 0% to 100% load conditions at a fixed speed of 1500 rpm combustion, and emissions characteristic were evaluated and compared with base fuel. The outcomes indicated that the use of B20 and B40 blends without hydrogen led to reduced BTE because of their lower cetane number and

Anbarasan, B, M, Kumaresan, Balamurugan, S, Rajesh, Munnusamy

Flow-Based Corrosion Analysis of NBR-PVC Fuel Hoses in Ethanol-Gasoline Blends

2026-28-0079

2/12/2026

The integration of ethanol into gasoline presents compatibility challenges for automotive fuel-system materials. In this study, the degradation of NBR-PVC fuel hoses exposed to ethanol-gasoline blends (E30, E50, E70, and E100) was investigated under dynamic flow conditions. A custom-designed test rig simulates real-time fuel circulation for 1,200 h. FESEM, ATR-FTIR, and elemental mapping analyses revealed ethanol-induced degradation, including dehydrochlorination, plasticizer leaching, and filler detachment. Among the blends, E30 exhibited the least material degradation, whereas E100 showed significant surface damage and chemical alteration. This study recommends multilayered fuel hose structures with ethanol-resistant inner linings for enhanced durability.

PC, Murugan, L S, Adhitya, G, Arun Prasad, W, Beno Wincy, T, Karthi

Research on Active Predictive Speed Control of Dual-Fuel Engine for Hardware Real-Time Applications

03-19-01-0004

2/9/2026

The present article proposes an active observation speed prediction control algorithm architecture for embedded applications, with the aim of addressing the problems of complex operating conditions, strong perturbations, and high control real-time requirements of high-pressure direct injection (HPDI) dual-fuel engines. A nonlinear speed prediction model with diesel and natural gas injection mass as inputs has been established, and the nonlinear model predictive control (NMPC) method is used to realize the optimized control of engine speed. In order to enhance the operational efficiency of the algorithm on the embedded platform, a system has been developed that includes an event triggering mechanism and a warm-start strategy. These mechanisms work in tandem to dynamically adjust the computation cycle. Additionally, a torque reduced-order expansion state observer (RESO) has been integrated to improve the accuracy of perturbation estimation and computational efficiency. The model-level

Yang, Xinda, Li, Yunhua, Chen, Dongdong, Li, Yao, Zhang, Shutao, Zhao, Feiyang, Yu, Wenbin

Potential of a Hydrogen Fuel-Share Combustion Concept for a Conventional Medium-Speed Marine Diesel Engine

2026-01-5007

2/2/2026

To meet the International Maritime Organization’s (IMO) short-term greenhouse gas (GHG) reduction targets, partial decarbonization of the existing fleet, often powered by medium-speed diesel engines, is required. One approach for reducing CO2 emissions is to enrich the charge air with hydrogen to substitute diesel. However, hydrogen’s high reactivity can lead to combustion abnormalities such as backfire, pre-ignition, and knocking, thus limiting the feasible admixture rates. These challenges are particularly relevant in medium-speed diesel engines designed for high power output and efficiency at low rpm. While hydrogen fuel-share has previously been tested in small-bore engines at moderate loads, this study investigates the influence on combustion and achievable hydrogen admixture rates in a medium-speed, 4-stroke diesel engine operating with up to 30 bar net indicated mean effective pressure (net IMEP). To minimize retrofitting efforts and to preserve diesel performance, the

Achenbach, Tobias, Meinert, Robert, Mahler, Kay, Kunkel, Christian, Rösler, Sebastian, Prager, Maximilian, Jaensch, Malte

Fuel Systems and Components - Electrostatic Charge Mitigation

J1645_202602 (Current)

2/1/2026

This SAE Surface Vehicle Recommended Practice deals with electrostatic charge phenomena that may occur in automotive fuel systems and applies to the following: Fuels that are in a liquid state at ambient temperatures and atmospheric pressures and are contained in vehicle fuel tanks that operate at or near atmospheric pressure. This includes gasoline and diesel fuels, as well as their blends with additives such as alcohols, esters, and ethers, whether the additives are petroleum based or bio-fuel based. The group of components that comprise the fuel system (in contact and not in contact with fuels). Other components in proximity to the fuel system that may be affected by electrostatic fields caused by the fuel system. Electrostatic phenomena that arise from, or are affected by, the following aspects of vehicle or fuel system operation: Flowing fuel in the fuel delivery system. Flowing fuel being dispensed to the vehicle while it is being fueled.

Fuel Systems Standards Committee

Rolls-Royce pursues pure methanol for marine engines

26TOFHP02_05

2/1/2026

Rolls-Royce has successfully tested the world's first high-speed marine engine powered exclusively by methanol on its test bench in Friedrichshafen, Germany. The company began this engine-development journey six years ago when it gathered experts to determine what the future fuel of the maritime industry should be, according to Denise Kurtulus, senior vice president of global marine at Rolls-Royce. “For us, it's clear. It's methanol,” she said. Rolls-Royce worked with industry partners as part of the joint project meOHmare, which is funded by the German Federal Ministry for Economic Affairs and Energy. Injection system specialist Woodward L'Orange and the WTZ Roßlau technology and research center contributed their expertise. Their goal was to not only develop a comprehensive concept for a CO2-neutral marine engine based on green methanol, but also to run it on the test bench by the end of 2025.

Gehm, Ryan

Increasing the Efficiency of Hydrogen Direct Injection Internal Combustion Engines through the Use of Miller Cycles and Water Injection

03-19-01-0001

1/31/2026

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

Recommendations for Fuel and Oil System Schematics

ARP1482C (Current)

1/28/2026

This document recommends and sets forth a set of symbols representing the components making up aircraft fuel and oil systems. The intended result is uniformity in system schematics so that they may be easily understood throughout the aerospace industry.

AE-5A Aerospace Fuel, Inerting and Lubrication Sys Committee

Development of a CNG-Diesel Dual Fuel Tractor with Mechanical Fuel Injection System

2026-26-0114

1/16/2026

Identification of renewable and sustainable energy solutions remains a key focus area for the engine designers of the modern world. An avenue of research and development is being vastly dedicated to propelling engines using alternate fuels. The chemistry of these alternate fuels is in general much simpler than fossil fuels, like diesel and gasoline. One such promising and easily available alternate fuel is compressed natural gas (CNG). In this work, a 3-cylinder, 3-liter naturally aspirated air-cooled diesel engine from the off-highway tractor application is converted into a CNG Diesel Dual fuel (CNG-DDF) engine. Part throttle performance test shows the higher NMHC and CO emissions in CNG-DDF mode which have been controlled by an oxidation catalyst in C1 8-mode emission test. A comparative performance shows that the thermal efficiency is up to 2% lower with CNG-DDF with respect to diesel. However, it has shown the benefit of 44% in Particulate Matter, while retaining the same NOx

Choudhary, Vasu, Mukherjee, Nalini, Kumar, Sanjeev, Tripathi, Ayush, Nene, Devendra

Establishing a High-Pressure Direct Injection Hydrogen Engine Test Facility with Integrated Ammonia Fuel Capability: Technical Considerations, Safety Framework, and Best Practices

2026-26-0267

1/16/2026

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

For CNG and FFV Fuel Application Exhaust Valve Redesign and Robustness Improvement to Combat Abnormal Valve Guide and Seat Wear

2026-26-0125

1/16/2026

Today, passenger car makers around the world are striving to meet the increasing demand for fuel economy, high performance, and silent engines. Corporate Average Fuel Economy (CAFE) regulations implemented in India to improve the fuel efficiency of a manufacturer's fleet of vehicles. CAFE goal is to reduce fuel consumption and, by extension, the emissions that contribute to climate change. CNG (Compressed Natural Gas) engines offer several advantages that help manufacturers meet and exceed these standards. The demand for CNG vehicles has surged exponentially in recent years, CNG engine better Fuel efficiency and advantage in CAFÉ norms make good case for OEM & Customer to use more CNG vehicle. CNG is dry fuel compared to gasoline. These dry fuels lack lubricating properties, unlike conventional fuels like petrol, diesel and biofuels, which are wet and liquid. Consequently, the operations and failures associated with these fuels differ. The materials and designs of engine parts, such as

Poonia, Sanjay, Kumar, Chandan, Sharma, Shailender, Khan, Prasenjit, Bhat, Anoop, P, Prasath, Neb, Ashish

Optimization of Propeller Shaft Design to Eliminate Launch Undulation (Lateral Shake) and Vibration Level

2026-26-0334

1/16/2026

During vehicle launches in 1st gear, a lateral shake (undulation) and a pronounced metallic hitting noise were observed in the underbody. The noise was identified as the propeller shaft's second universal joint (UJ) yoke striking the fuel tank mounting bracket. Sensitivity to these issues varied with acceleration inputs: light pedal input during a normal 1st gear launch on a flat road resulted in minimal undulation, whereas wide open throttle (WOT) conditions in 1st gear produced significant lateral shake and intensified hitting noise. Further investigation revealed that the problem persists across all gears and occurs consistently during normal driving conditions, with continuous impact between the propeller shaft yoke and the fuel tank mounting bracket. Extensive experimental measurements at the vehicle level indicated that these issues were primarily caused by the center-mounted propeller shaft joint deviating from its central position and rotating eccentrically under torque. This

Sanjay, L, S, Manickaraja, Kumar, Sarvesh, Kanagaraj, Pothiraj, Senthil Raja, T, B, Prem Prabhakar, M, Kiran

Analysis of Indian Patent Landscape on Alternative Fuels with a Focus on Hydrogen Fuel Cells and Hydrogen Internal Combustion Engines

2026-26-0262

1/16/2026

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

Early Prediction of CNG Filling Time Using Artificial Intelligence for Design Optimization

2026-26-0662

1/16/2026

Over the past few decades, Compressed Natural Gas (CNG) has gained popularity as an alternative fuel due to its lower operating cost compared to gasoline and diesel, for both passenger and commercial vehicles. In addition, it is considered more environmentally friendly and safer than traditional fossil fuels. Natural gas's density (0.7–0.9 kg/m3) is substantially less than that of gasoline (715–780 kg/m3) and diesel (849–959 kg/m3) at standard temperature and pressure. Consequently, CNG needs more storage space. To compensate for its low natural density, CNG is compressed and stored at high pressures (usually 200-250 bar) in on-board cylinders. This results in an effective fuel density of 180 kg/m3 at 200 bar and 215 kg/m3 at 250 bar. This compression allows more fuel to be stored, extending the vehicle's operating range per fill and minimising the need for refuelling. Natural Gas Vehicles (NGVs), particularly those in the commercial sector like buses and lorries, need numerous CNG

Choudhary, Aditya Kant, Petale, Mahendra, Dutta, Surabhi, Bagul, Mithilesh

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