Browse Topic: Fuel systems

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Sustainable Engines with carbon-neutral fuels – Fast Adaptation for Efficient Multi-Fuel Operation by tailored charge motion design2025-01-0534To be published on 11/25/2025
As a fundamental element of global measures to reduce the carbon footprint of the commercial transport and the mobile machinery and equipment sector, carbon-neutral fuels are increasingly coming into focus for heavy applications where electrification is seems to be actually not a viable option. In addition to diesel substitute fuels, alternative energy carriers like natural gas, hydrogen, methanol and ammonia are gaining increasing attention worldwide. The energy conversion of these fuels is typically taking place on the principle of premixed combustion, which places different demands on fuel injection and mixture formation, supported by proper in-cylinder charge motion and turbulence, compared to current highly optimized diesel-like combustion. Accordingly, the demand to layout multi-fuel capable engine designs centers to a high share on the above mentioned cylinder head design that can burn these different fuels with high efficiency and at the same time support a high degree of
Koerfer, Thomas, Dhongde, Avnish, Boberic, Aleksandar, Zimmer, Pascal, Pischinger, Stefan
Investigation of Active Pre-Chamber Ignition on an Optically Accessible Ultra-Lean DI Hydrogen Engine2025-01-0524To be published on 11/25/2025
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
Impact of Biodiesel on fuel filtration system and proposed best practices2025-28-0227To be published on 11/06/2025
Biodiesel acceptance and consumption has increased rapidly from the year 2018 onwards primarily as a result of government policies (Mandates in few cases); the consumption of local Make Biodiesel feedstock potentially reduces import of crude oil to save fuel import costs. Currently biodiesel usage is unregulated and non-standardized in few countries and in the cases where it is mandated and well controlled by local government. A sudden spurt in usage of unregulated, non-standardized Biodiesel started showing its consequences such as reduced fuel filter life, degradation of various engine related parts due to material compatibility issues with biodiesel demands in-depth study, research and creation of recommendations/best practices for the usage of Biodiesel in various applications. This paper will focus on roadmap of understanding the challenges related to usage of biodiesel (storing and handling of biodiesel at application site), technical challenges and its impact on fuel filtration
Bhalerao, Hariprasad, Shah, Avani, Khedkar, Prashant
Analysis of Injected Mass Shot-To-Shot Dispersion and Injection Rate Profile for a PFI Injector in Actual Operating Conditions2025-32-001911/03/2025
In order to improve engine emission and limit combustion instabilities, in particular for low load and idle conditions, reducing the injected fuel mass shot-to-shot dispersion is mandatory. Unfortunately, the most diffused approach for the hydraulic analysis of low-pressure injectors such as PFIs or SCR dozers is restrained to the mean injected mass measurement in given operating conditions, since the use of conventional injection analyzers is unfeasible. In the present paper, an innovative injection analyzer is used to measure both the injection rate and the injected mass of each single injection event, enabling a proper dispersion investigation of the analysed low pressure injection system. The proposed instrument is an inverse application of the Zeuch’s method, which in this case is applied to a closed volume upstream the injector, with the injector being operated with the prescribed upstream-to-downstream pressure differential. Further, the injector can inject freely against air
Postrioti, Lucio, Maka, Cristian, Martino, Manuel
Experimental Study of hCNG on Single Cylinder 395cc Spark Ignition Engine for Performance and Exhaust Emission2025-32-005011/03/2025
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
Knock Sensors for Two Wheelers Applications2025-32-007911/03/2025
This paper describes the design and characteristics of the knock sensor. The sensor is already used as a commodity product for automotive applications and used by all automotive OEMs for spark ignited combustion engines. With the arrival of the electronic fuel injection on the two wheelers, further optimization of the combustion can be obtained. Although there are many publications on the engine knock strategy, little is known publicly about the sensor itself. The knock sensor is an accelerometer based on a piezoelectric component; it provides an analog signal of the engine vibration. The Electronic Control Unit will filter the signal according to a specific strategy and defines the presence and intensity of the engine knock. The ECU will act accordingly on the ignition timing. The inner structure as well as the mechanical and electrical interface are described in this article.
van Est, Jeroen, Prieu, Corentin
Development of the Hydrogen Fueled Internal Combustion Engine for Off-Road Applications2025-32-006611/03/2025
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
Impact of Water Injection on Emission Formation in an HVO-Fuelled NRMM Engine2025-32-006711/03/2025
Water injection in diesel engines is a well-known method of lowering combustion temperatures and thus reducing nitrogen oxide (NOx) emissions. In this study, the influence of water injection in hydrogenated vegetable oil (HVO) operation on NOx formation, particulate emissions and ignition delay is analyzed in comparison to diesel operation on a John Deere JD4045 tractor engine. Both the fuel (HVO) and the water injection system were designed as ‘drop-in’ solutions that enable rapid implementation to reduce emissions, even in existing vehicle fleets. The standard engine control unit of the JD4045 engine was therefore used for the tests. A single water nozzle was installed downstream the charge air cooler to integrate a water injection system. The three operating points of interest were: (1) low speed and high load without exhaust gas recirculation (EGR), (2) high EGR rates at low speed and medium load and (3) the engine's ‘sweet spot’ regarding the emission-tradeoff at high speed and
Fuhrmeister, Jonas, Mayer, Sebastian, Günthner, Michael
Development of 2-Cylinder Diesel Engine for European Quadricycles to Achieve EURO 5+ Standard2025-32-006811/03/2025
The EURO 5+ standard (134/2014/EU) has been enforced in the year 2025 for quadricycle in Europe. The exhaust emission regulation under this standard has significantly tightened compared to the EURO4. Also, this standard limits vehicle weight, which remains unchanged from the EURO4 standard. We introduce the unique technologies to meet EURO5+ standard in this paper. Emission limit values of the EURO 5+ standard are more stringent, requiring an 84% reduction in NOx and a 94% reduction in PM compared to the previous standard. Diesel engines with mechanical injection control systems for the previous standard are required significant technological advancements to meet EURO 5+ standard of exhaust emission. The adoption of engine aftertreatment components such as SCR (Selective Catalytic Reduction) for NOx reduction and DPF (Diesel Particulate Filter) for PM reduction are common solution. However, to meet this new regulation, adding the weight of these after-treatment parts would cause the
Nagai, Naotaro, Tennomi, Masanari, Tamura, Akira, Mochizuki, Hiroaki, Kobayashi, Yasushi, Onishi, Takashi
Analysis of Combustion Process in HVO-Hydrogen Dual-Fuel Operation Using Simultaneous Imaging of OH* and CH* Chemiluminescence2025-32-005311/03/2025
This study investigated the combustion process in a hydrotreated vegetable oil (HVO)–hydrogen dual-fuel operation using simultaneous imaging of the OH* and CH* chemiluminescence in a rapid compression and expansion machine (RCEM). In this operation, hydrogen served as the primary fuel, ignited by a small quantity of pilot fuel. CH* chemiluminescence was primarily detected in the pilot fuel combustion regions, whereas OH* chemiluminescence was detected in both the pilot fuel and hydrogen combustion regions, enabling the separation of pilot ignition and hydrogen flame propagation. The combustion mechanism was found to proceed through four distinct stages: autoignition of the pilot fuel, combustion of the mixture in the lean pilot fuel region, propagation of the hydrogen–air premixture flame, and flame propagation toward the wall and squish area. Furthermore, the effects of the pilot injection parameters on the combustion characteristics were systematically evaluated by varying the
Yukitani, Takumi, Une, Naoto, Mukhtar, Ghazian, Horibe, Naoto, Kawanabe, Hiroshi, Koda, Kazuyuki, Hiraoka, Kenji
Transient Helium Jet Evolution Using High Speed Schlieren Imaging2025-32-005711/03/2025
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
Development of a Combined Injection and Ignition Unit for a Gas Engine with Direct Hydrogen Injection Integrated into the Standard Spark Plug Access Hole2025-32-005911/03/2025
To achieve the desired fuel switch from natural gas to hydrogen in internal combustion engines for combined heat and power units, it is necessary to make some adjustments to the fuel supply system. External gas mixers increase the probability of backfiring when natural gas is replaced by hydrogen. In addition, the low density of hydrogen results in a loss of power. Therefore, direct gas injection is preferred when using hydrogen. A drawback of direct injection is the requirement of higher injection pressures to achieve the desired fuel mass and mixture homogeneity as well as the additional access to the combustion chamber for the direct gas injector in the cylinder head. This paper proposes an alternative approach that does not necessitate the implementation of a high-pressure direct injection system nor additional access to the combustion chamber via the cylinder head. A combined injection and ignition unit, called HydroFit, was developed which uses a sleeve inside the spark plug bore
Rischette, Nic, Holzberger, Sascha, Helms, Sven, Kettner, Maurice
Effect of In-cylinder Hydrogen Mixture Formation on Hydrogen Combustion2025-32-006511/03/2025
Countries around the world are making long-term efforts to reduce greenhouse gas emissions in response to global climate change, with a target of Zero greenhouse gas emissions by 2050. In the automotive sector, discussions are ongoing on carbon-free powertrains in the future. Hydrogen is a fuel that can achieve zero carbon emissions and production, and is positioned as a key technology that is expected to play an active role in a wide range of fields, including power generation, transportation, and industry. Hydrogen engines are attracting increasing attention because conventional engine components can be diverted. In particular, hydrogen direct injection engines are attracting attention in order to achieve high power and high efficiency. In a hydrogen direct injection engine, the generation of backfire can be suppressed by injecting high-pressure hydrogen in the compression process, but it is known that the formation of air-fuel mixture in the cylinder becomes difficult, which greatly
Hisano, Atsushi, Saitou, Masahito, Sakurai, Yota, Ichi, Satoaki
Development of Integrated Forming of New "NMAX" YECVT Parts Using the Plate Forging Method2025-32-000511/03/2025
Yamaha Motor Engineering Co., Ltd. provides plastic processing technology based on fuel tank press forming technology, and is developing various plastic processing methods, including forging, and developing mold equipment to realize them. This time, the core parts of the YECVT unit mounted on Yamaha Motor Co., Ltd.'s small premium scooter "NMAX" were not made by welding individual parts to each other, but by integrally forming them from a single thick plate using the cold forming method, resulting in lightweight, compact, high-strength, high-precision parts. By incorporating a composite plastic processing method that takes advantage of the characteristics of the material while making full use of analysis technology and mold technology, we were able to develop a composite plastic processing method (plate forging method) that creates new added value and mass produce it. In addition,this development has made it possible to achieve a thickness increase of 1.7 times the standard material
Hongo, Hironari, Tamaru, Shogo, Uda, Shinnosuke
Development of Automatic Calibration System for PFI Engines2025-32-008411/03/2025
This report summarizes the research findings on fuel injection calibration methods, aiming to improve engine performance and reduce environmental impact. In PFI (Port Fuel Injection) engines, the injected fuel adheres to the port walls and mixes with air as it vaporizes, then flows into the combustion chamber. Traditionally, the fuel injection quantity is determined by the base map, which is calibrated for a steady state, and corrections for transient conditions. During steady-state operation, the air-fuel ratio of the mixture is uniquely determined by the amount of fuel injected, allowing for reproducible calibration. However, during transient conditions, the amount of fuel adhering to the walls and the amount vaporized do not balance, necessitating transient compensation to achieve the desired air-fuel ratio. Traditional transient compensation has been adapted for each engine model based on experience to accommodate differences in port shapes and injector placements. This approach
Haraguchi, Kazuki
Preliminary Development of a Novel 2-Stroke Petrol Engine for a Hybrid Sport-Tourer Motorcycle2025-32-002511/03/2025
While hybrid electric powertrains are the standard for passenger cars, the application to motorcycles is almost nil. The reason is the increase in weight, cost and overall dimensions, which can compromise the layout and dynamics of the motorcycle. A viable path is to replace the standard internal combustion engine with a much smaller and lighter unit, which leaves room for the installation of the electric components. The 2-Stroke (2S) cycle technology, thanks to the double cycle frequency and inherent simplicity, can be the key to reduce engine dimensions, weight and cost, while keeping high power outputs. The HybridTec project, discussed in this paper, aims to develop a compact and lightweight V-90° two-cylinder 2S engine, coupled to an electric motor installed downstream of the gearbox (P3 configuration). The total installed power should be about 110 kW. The engine features loop-scavenging, actuated by a crankshaft-driven supercharger, while an exhaust rotary valve and electronic
Rinaldini, Carlo Alberto, Scrignoli, Francesco, Volza, Antonello, Mattarelli, Enrico, Montanari, Luca, Magnani, Gianluca
The Study of Major Noise Sources of a Diesel Engine Using Acoustical Duct Method2025-28-041910/30/2025
The internal combustion engine has mechanized the world. Since the early 1900s, it has become a prime source of mechanical power. In modern times, petrol and diesel engine-powered vehicles find wide application in the field of transport and agriculture. However, the progress has resulted in newer problems. Due to the high density of internal combustion engines, the world over has resulted in the severe pollution problem. They are classified as air and noise pollution. Air pollution is caused due to dispersion of emitted from engine exhaust to the atmosphere at different concentration levels. Similarly, the emission of unwanted sound from engine structure, intake and exhaust are the principal sources of noise pollution. Excessive noise can have severe psychological and physiological effects on human beings like hearing loss, muscular and gastric effects and fatigue. In the present problem, we have studied mechanical-induced noise. Mechanical noise refers to noise generated by the
Goel, Arunkumar, Meena, Avadhesh Kumar
First Investigation of Ducted Fuel Injection on a Retrofitted Heavy-Duty Multi-Cylinder Production Engine04-19-01-000510/22/2025
Ducted fuel injection (DFI) was tested for the first time on a production multi-cylinder engine. Design-of-experiments (DoE) testing was carried out for DFI with a baseline ultra-low sulfur diesel (ULSD) fuel as well as three fuels with lower lifecycle carbon dioxide (CO2) emissions: renewable diesel, neat biodiesel (from soy), and a 50/50 blend by volume of biodiesel with renewable diesel denoted B50R50. For all fuels tested, DFI enabled simultaneous reductions of engine-out emissions of soot and nitrogen oxides (NOx) with late injection timings. DoE data were used to develop individual calibrations for steady-state testing with each fuel using the ISO 8178 eight-mode off-road test cycle. Over the ISO 8178 test, DFI with a five-duct configuration and B50R50 fuel reduced soot and NOx by 87% and 42%, respectively, relative to the production engine calibration. Soot reductions generally decreased with increasing engine load. Hydrocarbon and carbon monoxide emissions tended to increase
Ogren, Ryan M., Baumgard, Kirby J., Radhakrishna, Vishnu, Kempin, Robert C., Mueller, Charles J.
Research on Vehicle Fuel Abnormal Reduction Monitoring and Alert System Based on Dual-Mode Energy-Saving Control Technology2025-99-002510/17/2025
As an important bridge connecting cities and rural areas, highway transportation has an irreplaceable role in regional economic development [1]. Accompanied by the booming development of long-distance transportation industry, strengthening highway transportation is of great significance to improve people's living standards [2], but because of the special characteristics of truck transportation, fuel theft is frequent, seriously endangering the driver's life and the safety of goods transportation, although the police in the severe crackdown, but fuel theft seems to be in addition to inexhaustible, truck drivers lose oil incidents still occur from time to time, due to the increasingly serious energy problems, the world's countries have Due to the increasingly serious energy problems, countries around the world have formulated strict automotive fuel consumption rate (hereinafter referred to as fuel consumption) regulations [3], in the transportation process to prevent fuel theft is of
Liu, Yuzhen, Duan, ShuWen
Influence of Twin-Scroll Turbocharging on the Performance of Direct Injection Gasoline Engine2025-01-507010/16/2025
In order to further understand the effect of twin-scroll turbocharging on the engine performance, this paper adopts a combination of one-dimensional numerical simulation and experimental research methods to compare the effects of two-scroll and single-scroll turbocharging on the power and fuel economy of direct injection gasoline engine. The research results show that, compared with the single-scroll turbocharger, twin-scroll turbocharger increased the low-end torque for 16% and 32% at 1000 r/min and 1500 r/min, respectively. However, the average fuel consumption has increased 1.3% at part load with twin-scroll turbocharger due to the pumping loss. Compared with a turbocharged port injection engine with a displacement 1.2 times that of the former, the twin-scroll turbocharged engine saved 11% fuel economy at part loads. The fuel consumption is saved 11% at part loads with twin-scroll turbocharger. This research first establishes the 1D simulation capability in twin-scroll turbocharger
Yu, Xiaocao
Factors Influencing Energy Consumption in Plug-In Hybrid Vehicles: A Field Study2025-01-041410/07/2025
The paper assesses the impact of key factors influencing energy consumption for a Plug-in Hybrid Vehicle (PHEV) passenger car based on actual operating conditions over a period of one year. The tests were carried out in various climatic conditions, by random drivers, on the roads and streets of a medium-sized city in Poland. The use of PHEV with the prepared measuring procedure allowed for the analysis of energy consumption separately for the internal combustion and electric drive system. The total energy consumption directly depends on the way the car is used and on the availability of energy in fuel tank and traction battery. The calculated energy consumption varied from 20.19 to 41.97 kWh/100 km. The results were compared to other vehicles operated in real conditions, registered in a public database. The recorded minimum values of energy consumption correspond to the electric drive system, and the maximum values to the internal combustion drive system.
Mamala, Jaroslaw, Graba, Mariusz, Bieniek, Andrzej, Prażnowski, Krzysztof, Hennek, Krystian, Burdzik, Rafał
Study on Oil Film Thickness of Piston Skirt Pattern Coating in a Commercial Vehicle Diesel Engine2025-01-039710/07/2025
In recent years, there has been a trend towards lower engine speeds and downsizing of diesel engines to improve fuel efficiency. This has the advantage of reducing frictional losses in the hydrodynamic lubrication condition but causes severe lubrication in the mixed lubrication condition. In order to reduce friction losses without the risk of abnormal wear or seizure, pattern coatings of the piston skirt area have been proposed. In this study, the oil film thickness between piston and cylinder was measured to investigate the effect of pattern coating on the oil film thickness. The oil film thickness between the piston and cylinder were measured by the laser-induced fluorescence method using the optical fibers embedded in the cylinder. The oil film thickness on the piston skirt was successfully measured under the engine operating conditions for the medium duty Direct Injection (DI) diesel engine. The oil film thickness for the pattern coatings was compared with that for the solid
Tanimoto, Keisuke, Ito, Akemi, Sumoto, Masayuki
Remaining Useful Life prediction of Engine Fuel System Using Machine Learning2025-01-037710/07/2025
Reliability and uptime are critical priorities in the automotive industry, prompting a shift toward predictive maintenance (PdM) to minimize unexpected failures and associated costs. This study presents a machine learning-based framework for early prediction of engine fuel system failures using embedded field performance data. This study introduces a machine learning-based framework for predicting failures and estimating the remaining useful life (RUL) of mid-range diesel engines with high-pressure common rail fuel systems in vehicles using classification and regression models applied to embedded field performance analysis data, aiming to enhance reliability and reduce unplanned downtime. Two classification models --- Random Forest and XGBoost top our model metrics chart. They were further tuned and evaluated, with XGBoost achieving superior performance, including 94% accuracy and 87% precision, and a low false positive rate of 0.01, enabling an 8-day lead time for proactive
Wang, Tingting, Goswami, Anil, Akinola, Michael, Yang, Tina, An, Qi
Optimization of CI Engine Operation with DME on an FTP Cycle2025-01-039410/07/2025
Fuels that can be produced in a sustainable manner are of high interest because they can provide an essential step toward net zero emissions vehicles. This study examines the combustion of one such fuel, Dimethyl Ether (DME), in a compression ignition, 4-cylinder, 2.2L engine. Testing was conducted using the Federal Test Procedure (FTP) certification cycle from the US Environmental Protection Agency (EPA). Different sets of calibration maps were designed to target low-NOx (30-50ppm) by using high EGR and intake throttle and high-NOx (approximately 1000ppm) using no EGR. An intermediate, mid-NOx calibration was also evaluated. Varying calibration approaches yielded total integrated engine out emissions ranging from 118 to 145gCO2/km, all below the 191gCO2/km from the baseline diesel. The corresponding NOx+UHC and CO emissions were also evaluated. The mid-NOx calibration was overall more favorable, as it met TIER 3-Bin 20 emissions requirements with the current efficiencies of the base
De Ojeda, William, Wu, Simon (Haibao), Harrison, Christopher, Hall, Carrie, Arslan, Elaheh, Pulpeiro Gonzalez, Jorge
An Assessment of Performance of Power Pack Fueled with Nano-Enhanced Biodiesel Biobutanol Blends Operated with Optimal Operating Parameters2025-01-506710/02/2025
As of today, scenario using the renewable resources from the waste and biomass is essential to decrease the dependence on the fossil fuel imports. This study is to use the waste castor seed into oil and for powering the power pack along with biobutanol extracted from waste of fruits and vegetables from the food processing outlets. As a first step the possible combination of the fuel blend is being chosen by preparing various proportions of castor oil biodiesel (from 100% to 55% in steps of 5%) and biobutanol (0%–35% in increments of 5%). The blends are being tested for the phase separation test in the environment of 25°C for a period of 30 days. The chosen blend (25% biobutanol and rest castor oil biodiesel 75CBD25BB) has been tested for the performance in power pack, which is used for diesel as primary fuel. This blend was further tested by optimizing the parameters—compression ratio, fuel injection timing, and nozzle opening pressure of the test power pack through L9 orthogonal array
Prabakaran, B., Yasin, Mohd Hafizil Mat, Mamat, Rizalman
Review on Compatibility Considerations of Fuel System Elastomers with Paraffinic Fuels04-18-03-001709/10/2025
The possibility of reducing CO2 emissions through sustainable paraffinic fuels opens opportunities for the continued use of existing infrastructure and combustion systems. At the same time, fuel switching also presents challenges in terms of the materials used. The changing composition of paraffinic fuels and their impact on plastic materials is a frequent topic of discussion. Compared to distillate diesel, neat paraffinic fuels contain almost no aromatics, which are known to cause swelling in plastics, especially elastomers. This literature review aims to examine and summarize studies on the influence of paraffinic fuels compared to distillate diesel on elastomers. On the fuel side, attention will be given to fuels with different total aromatics content and neat paraffinic fuels. In the field of elastomers, materials used for sealing applications and hoses are analyzed in detail. Special attention will be paid to NBR, FKM, and EPDM. The review aims to answer three questions. The first
Conen, Tobias, Häfele, Benjamin, Dahlmann, Rainer
Analysis of Momentum Flux Distribution in Jets Produced by a Hydrogen Direct Injection System2025-24-006509/07/2025
The adoption of hydrogen as carbon-free fuel for internal combustion engines in both transport and off-road applications could offer a significant contribution towards carbon neutrality. In the technical pathway to the conversion of conventional engines operating with liquid fuels to hydrogen, a key role is played by the injection systems. In particular for direct-injected combustion systems, the achievement of an adequate capability to control the gas jets development and the following mixing with air in the combustion chamber is mandatory in order to govern the heat release rate, so to obtain high efficiency levels while limiting the knock tendency and NOx formation. In order to achieve this complex task, injector caps featuring multiple holes (often non uniform in size) can be installed on the injector nozzle so to properly distribute hydrogen obtaining a proper matching with the combustion chamber design and with the air charge flow structure. To this end, the development of both
Postrioti, Lucio, Fontanesi, Stefano, Martino, Manuel, Maka, Cristian, Breda, Sebastiano, Falcinelli, Francesco, Ricci, Andrea
Spray Dynamics and Collapsing Process of Methanol in a Lateral-Cylinder-Mounted DI Injector2025-24-006309/07/2025
The morphology and collapsing behavior of fuel sprays play a critical role in determining atomization and vaporization characteristics, directly influencing combustion efficiency and emission formation in direct injection systems. In this study, spray dynamics and collapsing processes of methanol and gasoline fuels were examined using a lateral-cylinder-mounted direct injection (DI) injector in a constant volume combustion chamber (CVCC). A tomographic imaging technique was applied to analyze the spatial and temporal characteristics of fuel sprays. Extinction imaging was performed to capture the distribution of droplets within the spray, and the liquid volume fraction (LVF) was quantified based on the Beer-Lambert law. By acquiring extinction images from multiple viewing angles, 3D tomographic reconstructions of the spray morphology were achieved, providing detailed insights into the structural evolution of the sprays during injection. The high latent heat of vaporization of methanol
Kim, Hyunsoo, Lee, Seungwon, Bae, Sumin, Hwang, Joonsik, Bae, Choongsik
Investigation of the Combustion Process of a Thermally Conditioned Active Prechamber in Monovalent Operation with Ammonia2025-24-002809/07/2025
The debate over synthetic fuels is intense especially in sectors with a high energy demand like maritime [1, 2]. Hydrogen production from renewable sources is growing, but immediate measures for decarbonization are needed [3, 4]. In this context, the project MethMag was funded, and a gas engine for methane combustion with an innovative cooling concept and a purged prechamber (PC) spark plug was virtually developed [5, 6]. Validation with data from the test bench demonstrates that the simulations accurately represent the operating conditions [7, 8]. This combustion process is adapted for ammonia, which is being considered as a climate-friendly fuel of the future, particularly in maritime transportation [4, 9]. This fuel faces significant combustion challenges and is therefore mostly considered in complex, bivalent systems [10]. In particular, the prechamber is examined regarding the ignitability of ammonia. The overarching objective is to eliminate the necessity for a secondary fuel
Rothe, Paul, Bikas, Georgios, Mauss, Fabian
Cylinder Balancing Algorithms: Enabling the Transition to Future Fuels in Large-Bore Spark-Ignited Engines2025-24-001709/07/2025
Large-bore spark-ignited engines equipped with individual cylinder injection systems require advanced balancing strategies to achieve optimal combustion performance and mitigate risks associated with abnormal combustion phenomena. The integration of highly reactive fuels, such as hydrogen, introduces additional challenges for high-power-density, low-speed engines. This study investigates closed-loop cylinder balancing strategies utilizing real-time cylinder pressure feedback to optimize engine operation. Key performance metrics were evaluated on a 20-cylinder medium speed stationary gas engine (8.5 MW electrical power) under eight different control strategies. The results indicate that the tested balancing methods reduce average knock intensity and variation of combustion peak pressure across all cylinders compared with original manufacturer control strategy. Furthermore, the study demonstrates that a well-balanced engine offers significant advantages, including enhanced power output
Martelli, André, Penaranda, Alexander, Martinez, Santiago, Zabeu, Clayton, Salvador, Roberto
Combustion System Optimization of Commercial Vehicle Hydrogen Engines via 3DCFD Simulations and Single Cylinder Engine Measurements: Injector Cap, Injection Strategy and Intake Duct Design2025-24-000809/07/2025
The development of hydrogen fueled engines has dramatically accelerated in recent years. They have gained much in operating reliability and the specific power outputs is at least comparable to those of current natural gas engines. This has been made possible by combining specific development tools derived from the development of compression-ignition and spark-ignition engines. These include jet visualization techniques (Schlieren, PIV, and LIF), video endoscopy on engine, and 3-D fluid dynamics simulations. In hydrogen engines for commercial vehicles, efforts have so far been made to keep engine components as unchanged as possible from similar diesel or gasoline versions. Similarly, some manufacturers have favored the port fueled injection (PFI) solution because it is easier to implement than the in-cylinder (DI) injection one. The present work concerns the evaluation of the further improvement potential made possible by using direct injection (DI) technology, and intervening on both
Gaballo, Maria Rosaria, Iacobazzi, Marino, Burtsche, Thomas, Cornetti, Giovanni
LES and RANS Modeling of a Hydrogen Low-Pressure Direct-Injection Injector2025-24-006609/07/2025
Hydrogen direct injection is a promising strategy for enabling high-efficiency, low-emission powertrains. However, challenges related to mixture stratification and jet modeling persist, particularly under engine representative conditions. This study numerically investigates a simplified injector model, focusing on the downstream hydrogen jet behavior from of a hydrogen low-pressure direct-injection jet-forming cap under both constant-volume chamber (CVC) and engine conditions. The primary objective is to evaluate numerical methodologies and explore model simplification strategies that remain computationally feasible while preserving physical fidelity—particularly relevant for early-stage hydrogen injector development. Experimental data serve as validation benchmarks across operating regimes. In the CVC platform, large eddy simulations (LES) provide turbulence-resolving insights that inform the refinement of Reynolds-averaged Navier–Stokes (RANS) models. RANS simulations are then
Menaca, Rafael, Liu, Xinlei, Silva, Mickael, Wu, Hao, Ben Houidi, Moez, Mohan, Balaji, Cenker, Emre, AlRamadan, Abdullah, Syed, Iltesham, Pei, Yuanjiang, Roberts, William, Im, Hong G.
Influence of Gas Pressure Levels on Injection Timing, Combustion Anomalies, and Emissions of a Hydrogen Gas Engine2025-24-005309/07/2025
A former diesel heavy-duty engine was retrofitted to hydrogen operation to simultaneously facilitate the shift from fossil to renewable fuels and maximize the quantity of reusable engine parts. Simply changing the fuel in this case does not make a properly working engine; the burning process needs to be realized in a premixed flame regime, rather than a diffusional flame regime. Therefore, an additional ignition source is necessary. A well-known characteristic of hydrogen is the low need for ignition energy and the wide range of ignitable air/ fuel ratios. Both must be considered to reach a diesel engine equivalent performance. Port fuel injection (PFI) and direct injection (DI) are commonly used in spark-ignited internal combustion engines. Some disadvantages, such as weak volumetric efficiency and combustion abnormal phenomena like backfire, are connected to PFI. To further improve the volumetric efficiency, high boost pressures are needed. To maximize volumetric efficiency with DI
Rößlhuemer, Raphael, Fellner, Felix, Fitz, Patrick, Prager, Maximilian, Jaensch, Malte
Experimental Investigations on the Effects of Injector Orientation in a Diesel-Gasoline-Fuelled Premixed Charge Compression Ignition Engine2025-24-004309/07/2025
Premixed Charge Compression Ignition (PCCI) presents a promising alternative to conventional diesel combustion (CDC), offering significant reductions in pollutant emissions by lowering local in-cylinder temperatures and enhancing fuel-air mixing. However, a significant challenge in implementing PCCI is controlling the start of combustion, especially given its narrow operating load range. This is primarily due to early ignition and knocking combustion at higher loads when using high-reactivity diesel fuel, which limits the practical applicability of PCCI mode in diesel engines. In the present study, experimental investigations are carried out on a light-duty diesel engine operating in PCCI mode using two fuel blends: 10% (D90G10) and 20% (D80G20) gasoline mixed with diesel on a volume basis. To facilitate combustion control and emission reduction, exhaust gas recirculation (EGR) and water vapor are used as charge diluents. A common rail direct injection (CRDi) system replaces the
Ranjan, Ashish Pratap, Krishnasamy, Anand
Development of a Compact Hydrogen Engine for Commercial Applications2025-24-006009/07/2025
As the individual and commercial vehicle industries seek sustainable alternatives to conventional internal combustion engines (ICEs), hydrogen-fueled rotary engines are emerging as a promising solution for several applications. This paper presents an innovative approach for the development of a hydrogen rotary engine that is integrated within a hybrid system. By exploiting the unique characteristics of rotary engines, such as compact size and high power-to-weight ratio, the electric machine, the battery and the rotary engine can be accommodated in the installation space of a conventional ICE with comparable power, despite the reduced power density of hydrogen as a fuel in ICEs. As a first step, the hydrogen engine is naturally aspirated and equipped with direct injection. To develop a suitable calibration for the engine’s application, the influence of calibration parameters such as ignition and injection are investigated. The study examines the influence of these on operating behavior
Endres, Jonas, Beidl, Christian, Hofmann, Silas
Study of a CI Engine for Off-Road Application in Diesel-Hydrogen Dual Fuel Configuration2025-24-005509/07/2025
Hydrogen as fuel in internal combustion engines is a promising solution for reducing greenhouse gas emissions, as its combustion produces only water vapor. One potential application is in dual fuel (DF) engines, where diesel is used to ignite the mixture, and hydrogen serves as the primary fuel. However, there is limited literature on the use of hydrogen in compression ignition (CI) engines for off-road applications running in dual fuel diesel/hydrogen, which motivates this study. The focus is on a 3-cylinder, 1-liter naturally aspirated (NA) engine with a compression ratio of 17.5:1 equipped with direct injection (DI) for diesel. Retrofitting the engine with 3 port fuel injectors, it was possible to feed the engine with hydrogen by the control system elaborated in the laboratory. The study aims to analyze dual fuel diesel/hydrogen combustion characteristics and the emissions across different engine speeds (from 1600 rpm to 3600 rpm) and loads (30%, 50% and 70%). The dual fuel
Gelé, Raphaël, Mancaruso, Ezio, Rossetti, Salvatore, Rousselle, Christine, Brequigny, Pierre
CFD-Driven Optimization of Diesel Injection for a Hydrogen-Diesel Dual Fuel Engine2025-24-004509/07/2025
Among the alternatives to the use of fossil diesel fuel, dual fuel combustion, leveraging hydrogen as the low-reactivity fuel, represents a promising approach for both reducing pollutant emissions and improving brake thermal efficiency. In addition, this innovative combustion mode requires minimal modifications to the existing Diesel engines architecture. This study was conducted on a Diesel engine (naturally aspirated, 3-cylinder, 1 L, direct injection), properly modified by the authors to operate in dual fuel mode with port fuel injection of hydrogen. A set of experimental data was used to calibrate the 1D and the 3D-CFD models for both Diesel and diesel-hydrogen dual fuel configurations. The AVL FIRE M 3D-CFD software was employed to model diesel injection and combustion, while the gas exchange process was analyzed by GT-Power. The validated 3D-CFD model was then leveraged to optimize the baseline diesel injection strategy in dual fuel mode, minimizing diesel consumption while
Rinaldini, Carlo, Pisapia, Alfredo Maria, Scrignoli, Francesco, Volza, Antonello, Rossetti, Salvatore, Mancaruso, Ezio
Experimental Investigation of Usage Limits of Various Alcohol-Based Fuels in Spark Ignition Engine2025-24-003109/07/2025
Current ambitious targets of transport utilized fossil fuels replacement pose a considerable challenge while transportation affordability, energetic and precious materials security are to be maintained. Most of current solutions oriented towards passenger cars fossil fuel replacement by more renewable resources are dependent on one superseding method only. On other hand, each of them exhibits some drawbacks and benefits while a reasonable combination could mitigate number of limitations and include many advantages. Such a solution could be usage of a wide range of liquid fuels from renewable resources in a suitable spark ignition engine accompanied by common battery electricity storage. The aim of this experimental work was to develop and demonstrate possibilities and results of an uncomplex engine adaptation to a wide range of fuels obtainable from renewable resources suitable as a range extender to commonly proposed electric cars. The approach chosen used standard gasoline as a
Pechout, Martin
Computational Fluid-Dynamics Analysis of the Effect of Ethanol-Air Mixture Supply in a Heavy-Duty Engine2025-24-002909/07/2025
As part of the Bio-FiRE-for-EVer research project aiming to propose a solution for off-grid charging stations based on the adoption of a reciprocating engine, this study investigated the combustion development and pollutant emissions of an 8.7 l six-cylinder heavy-duty PFI internal combustion engine fueled by ethanol. The reference experimental case features critical issues in the formation of the air-fuel, mainly due to the slow evaporation rate of the alcohol fuel inside the intake manifold via a single point injection, providing a non-uniform and averagely rich (λ=0.89) reactant mixture inside the cylinders. For this purpose, an in-depth analysis of the in-cylinder phenomena is performed by using a CFD solver for the reacting flow. A geometry of the cylinder system complete with intake and exhaust ducts is created for calculations with the three-dimensional Ansys FORTE code. The inclusion of the inlet duct in the computational domain allows the experiencing of several setups of the
De Robbio, Roberta, Cameretti, Maria Cristina, Palomba, Marco, Tuccillo, Raffaele
Characterization of Low-Density Gaseous Jet Structure and Vorticity Using PIV Technique2025-24-006709/07/2025
In view of the increasing interest towards hydrogen, such as its utilization for road transport sector decarbonization, the present study proposes the use of helium as substitute to characterize the jet structure through the use of the particle image velocimetry (PIV) technique. The experimental test campaign involved the use of a gaseous injector capable of delivering helium up to 50 bar in a constant volume chamber (CVC), which pressure has been varied in order to scrutinize the influence of environment density on jet structure. Two configurations were employed: one consisting of a free path of distribution of the jet, the second including a metal plate positioned perpendicularly 50 mm from the injector tip, thus making it possible to observe the jet – wall interactions under several conditions. The illumination was provided by a dual cavity Nd:YAG laser and a 4-megapixel camera used for image capture. The influence of pressure ratio (PR) was evaluated over a wide range, from 7 to 34
Cecere, Giovanni, Andersson, Mats, Merola, Simona, Irimescu, Adrian
Experimental Investigation of the Comparison between Helium and Hydrogen Jets Exiting a DI Outward-Opening Injector via Schlieren Technique2025-24-006809/07/2025
This paper deals with the hydrogen-to-helium jets comparison within the framework of the assessment of helium as a potential hydrogen surrogate. The comparison is centred on the assessment of the combined action of pressure ratio with gas properties on the dynamics of the jet exiting an outward-opening injector. The shots are performed at injection pressures and backpressures ranging from 21 to 36 bar and from 1.2 to 5 bar, respectively. The Schlieren technique is deployed to capture the jets images. The study demonstrates that at certain pressure ratios helium is an appealing solution bridging the lab safety with fidelity to hydrogen-like jet behaviour. Decreasing pressure ratio minimizes the hydrogen-to-helium difference in axial penetration and area, enabling helium to yield a hydrogen-like development. The findings underscore the impact of the pressure ratio on how the gas properties, such as density and diffusivity, dictate the evolution of the axial propagation and area
Coratella, Carlo, Tinchon, Alexis, Hespel, Camille, Dober, Gavin, Foucher, Fabrice
A Novel Nozzle Orifice Design of a Heavy-Duty Diesel Engine to Achieve Higher Thermal Efficiency with Significantly Reduced Heat Loss2025-24-003709/07/2025
This study investigated a novel nozzle orifice design to improve thermal efficiency. The offset orifice nozzle has holes drilled offset of less than 0.5 mm from the radial center of the nozzle. Engine performance test and in-cylinder combustion observation were carried out by means of a heavy-duty diesel engine. The experimental results demonstrated that the offset orifice nozzle achieved significant improvements in both heat loss and thermal efficiency, regardless of the compression ratio and operating load conditions. However, the underlying mechanisms have not been revealed yet. Therefore, investigation into the mechanisms behind heat loss reduction and thermal efficiency improvements with the offset orifice geometry is the purpose for establishing design guidelines for optimization. It was revealed by the combustion visualization that the flame tip length of the offset orifice nozzle was shortened with significantly wider flame cone angle from very close to the orifice exit even
Mukayama, Tomoyuki, Uchida, Noboru
Zero-Carbon Port Fueling for Heavy Propulsion through a Recuperated Split Cycle Engine2025-24-004409/07/2025
Upcoming global emissions regulations demand innovation in heavy-duty road and marine transport. This research explores emissions-compliant concepts using both experiments and simulations focused on the Recuperated Split Cycle Engine (RSCE), which separates compression and expansion to enable internal heat recovery and quasi-isothermal compression. A single-cylinder research engine representing the expansion cylinder of an RSCE demonstrated direct injection diesel and port injection hydrogen co-firing. A validated Chemkin-Pro Multi-Zone model first reproduced, then extended this work, evaluating partial diesel substitution with hydrogen or ammonia alongside secondary working fluids (SWF’s liquid N₂, H₂O, NH₃). For the extension, two variants of the split cycle architecture were employed; the RSCE in combination with hydrogen fueling for the heavy-duty road sector, and the novel recuperated reformed split cycle engine (R2SCE), a new architectural and simulation contribution enabling on
Wylie, Elisa, Panesar, Angad
High-Pressure Hydrogen Flows through Single- and Multi-Hole Nozzles: A Computational Study13-06-03-002409/01/2025
Efficient propulsion technologies that utilize alternative fuels are becoming increasingly critical to achieve high efficiency at the vehicle scale while fulfilling global regulations in terms of emissions and criteria pollutants. In this scenario, hydrogen (H2) represents an important and appealing part of the solution due to its molecular composition and unique physical and chemical properties. With reference to internal combustion engines, much research is needed to overcome technical challenges that make H2 use not yet viable at the industrial scale. This work focuses on the computational modeling of some of the fundamental aspects of H2’s physical behavior, which can be useful to the development of high-pressure H2 injection systems. Computational fluid dynamics simulations are discussed with the goal of understanding the near- and far-nozzle behavior of H2 using single- and multi-hole nozzles. This study presents the validation of the computational framework against literature
Torelli, Roberto, Park, Ji-Woong, Pei, Yuanjiang
Electrical Wiring Fuel CompatibilityAIR6820A (Current)08/06/2025
This SAE Aerospace Information Report (AIR) is limited to the subject of compatibility of wiring as part of aircraft Electrical Wiring and Interconnect Systems (EWIS) installed in and around aircraft fuel tanks.
AE-8A Elec Wiring and Fiber Optic Interconnect Sys Install
Aircraft Flexible Tanks General Design and Installation RecommendationsAIR1664A (Current)07/28/2025
This SAE Aerospace Information Report (AIR) includes general information about the various types and styles of flexible tanks and the tank-mounted fittings that adapt the tank to the surrounding structure and fluid-system plumbing. Recommendations are given relative to the dimensional layout of the tank when these recommendations serve to avoid tank fabrication problems and tank/structure interface problems. As a part of these recommendations, critical dimensions of plumbing adapter fittings are discussed and recommendations made. Tank manufacturing tolerances are given. Recommendations are made relative to cavity design and preparation to facilitate a reliable installation. The special installation requirements of nonself-sealing, self-sealing, and crash-resistant tanks are discussed. This document is not intended to replace the information or requirements of the military and commercial procurement specifications listed in Section 2. No attempt has been made, except in a very general
AE-5A Aerospace Fuel, Inerting and Lubrication Sys Committee
Ethanol Fuel as Enabler for High-Efficiency and Low-Soot Combustion in Dual-Fuel and Blend Modes03-18-04-002807/16/2025
Global climate initiatives and government regulations are driving the demand for zero-carbon tailpipe emission vehicles. To ensure a sustainable transition, rapid action strategies are essential. In this context, renewable fuels can reduce lifecycle CO2 emissions and enable low-soot and NOx emissions. This study examines the effects of renewable ethanol in dual-fuel (DF) and blend fueling modes in a compression ignition (CI) engine. The novelty of this research lies in comparing different combustion modes using the same engine test rig. The methodology was designed to evaluate the characteristics of various injection modes and identify the inherent features that define their application ranges. The investigation was conducted on a single-cylinder engine equipped with state-of-the-art combustion technology. The results indicate that the maximum allowable ethanol concentration is 30% in blend mode, due to blend stability and regulatory standards, and 70% in DF mode, due to combustion
Belgiorno, Giacomo, Ianniello, Roberto, Di Blasio, Gabriele
Aerospace Fuel System Specifications and StandardsAIR1408B (Current)07/16/2025
This report lists documents that aid and govern the design of aircraft and missile fuel systems. The report lists the military and industry specifications and standards and the most notable design handbooks that are commonly used in fuel system design. Note that only the principle fuel specifications for the U.S. and Europe (Military Specifications, ASTM, and Def Stan) have been included within this report. The specifications and standards section has been divided into two parts: a master list arranged numerically of all industry and military specifications and standards, and a component list that provides a functional breakdown and a cross-reference of these documents. It is intended that this report be a supplement to specifications ARP8615, MIL-F-17874, and JSSG 2009. Revisions and amendments which are correct for the specifications and standards are not listed. The fuel system design handbooks are listed for fuels and for system and component design.
AE-5A Aerospace Fuel, Inerting and Lubrication Sys Committee
Experimental Investigations on the Effects of Injector Design and Operating Parameters on PCCI Combustion in a Light-Duty Diesel Engine03-18-04-002607/09/2025
Due to increasingly stringent emission regulations, advanced combustion strategies, such as premixed charge compression ignition (PCCI), have emerged promising solutions for achieving low NOx and soot emissions. However, challenges such as increased unburned hydrocarbon (HC), carbon monoxide (CO) emissions, and a restricted engine operating load range remain unsolved. Since conventional diesel engines are not inherently designed for PCCI operation, re-optimizing engine parameters is essential. The primary objective of this work is to investigate the influence of injector orientation and nozzle spray angle on combustion parameters, performance, and emissions in a PCCI diesel engine. Initial parametric studies revealed that early direct injection combined with high fuel injection pressure limited the PCCI load range to 30% and 60% of the rated capacity with diesel, without and with EGR, respectively, accompanied by higher HC and CO emissions. To address these limitations, the injector
Ranjan, Ashish Pratap, Krishnasamy, Anand
Dispenser Nozzle Spouts for Liquid Fuels Intended for Use with Spark Ignition and Compression Ignition EnginesJ285_202507 (Current)07/09/2025
This SAE Recommended Practice provides standard dimensions for liquid fuel dispenser nozzle spouts and a system for differentiating between nozzles that dispense liquid fuel into vehicles with spark ignition (SI) engines and compression ignition (CI) engines for land vehicles. Current legal definitions only distinguish between “Unleaded Fuel” and “All Other Types of Fuel.” These definitions are no longer valid. This document establishes a new set of definitions that have practical application to current automobile liquid fuel inlets and liquid fuel dispenser nozzle spouts.
Fuel Systems Standards Committee
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