Browse Topic: Engine mechanical components

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Ammonia Combustion with Active Pre-Chamber Spark Plug - a CO2-free Combustion Process2025-01-0527To be published on 11/25/2025
As a zero carbon fuel, ammonia has the potential to completely defossilize combustion engines. Due to the inert nitrogen present in the molecule, ammonia is difficult to ignite or burn. Even if the ammonia can be successfully ignited, combustion will be very slow and there is a risk of flame quenching, i.e. the flame going out before the ammonia-air mixture has been almost completely converted. Both the difficult flammability and the slow combustion result in high ammonia slip, which should be avoided at all costs. The engine efficiency is also greatly reduced. Safe ignition and burn-through can be achieved by drastically increasing the ignition energy and/or using a reaction accelerator such as hydrogen. The planned paper will use detailed 1D and 3D CFD calculations to show how high the potential of ammonia combustion in an internal combustion engine is when an active pre-chamber is used as the ignition system. As a result of the flare jets penetrating into the main combustion chamber
Sens, Marc, von Roemer, Lorenz, Rieß, Michael, Fandakov, Alexander, Casal Kulzer, Andre
Knock Phenomenon Investigation In SI Engine fuelled with Ammonia-Hydrogen mixture2025-01-0532To be published on 11/25/2025
Ammonia is one of the most promising carbon-free fuels for decarbonizing sectors relying on thermal conversion processes, such as energy production and transportation. However, ammonia exhibits combustion properties that differ significantly from conventional fuels, including a low laminar burning velocity, narrow flammability limits, and a high autoignition temperature. To enhance the efficiency and stability of ammonia combustion in internal combustion engines (ICEs), high compression ratio engines are often combined with ignition promoters such as hydrogen, which can be obtained through on-board ammonia cracking. Nevertheless, the addition of hydrogen to ammonia fuel can promote the occurrence of knock. The objective of this study is to investigate knock propensity as a function of engine parameters as combustion chamber geometries and compression ratios. Experiments were conducted at different engine speeds (1000, 1500, and 2000 RPM), across several intake pressure conditions (from
Hurault, Florian, Brequigny, Pierre, Foucher, Fabrice, Rousselle, Christine
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
Monitoring of Long drill wear status through Vibration analysis using Time and Frequency domain2025-28-0252To be published on 11/06/2025
Hard carbon steel is used for drilling deep holes, such as C19, which has dimensions of 630 mm in length, 50 mm in breadth, and 125 mm in depth. Long twist drills with a diameter of 8 mm are used. Such drills are manufactured with larger helix than the traditional drills for increasing penetration efficiency. But, Prediction of long drill & tool replacement strategies during metal cutting are mostly depend on conservative estimation given by manufacturer's catalog. Hence, long drill while drilling cam shaft in automobile applications may be underutilized or over utilized. Now a day, Diagnostics software in advanced CNC machines are indicating hours of utilization of tools in bar chart. On the other hand, Utilization of long drill wear beyond the recommended range affects the quality of workpiece. As a result, several researchers have proposed the reliable approach of vibration-based online monitoring of drill flank wear over the past 20 years. In these works, the vibration sensor is
R. S., Nakandhrakumar, Raja, Selvakumar, Elumalai, Sangeethkumar, Velmurugan, Ramanathan, M, Ramakrishnan
Test methodology development for validating engine pulley bolt for accelerated durability2025-28-0234To be published on 11/06/2025
Engine is the prime mover of an automobile. Tractor is also equipped with an engine of higher capacity to meet the power requirement. Apart from powering the wheels, the engine also runs different accessories, such as a water pump, alternator, AC pump, oil pump, and so on. The power from the engine is transferred to accessories via chain drive or belt drive through the crankshaft pulley. During field testing, in one of the tractors, engine pulley mounting bolt failure was reported. The failure resulted in an immediate seizure of the engine, making the tractor standstill in the field. The root cause of the failure was unknown. There was a need to develop a component- or subsystem-level test methodology to address the issue quickly. In the current scope, an attempt was made to develop a subsystem-level laboratory test methodology to simulate the failure mode and to validate the design modifications in an accelerated manner. The failure mode was simulated in the lab, and different design
Chakraborty, Abhirup
Effective power management on diesel engine using electrified turbocharger.2025-28-0242To be published on 11/06/2025
The growing demand for improved fuel efficiency and reduced emissions in diesel engines has led to significant advancements in power management technologies. This paper presents a dual-function strategy that integrates electrified turbochargers to enhance engine performance and generate electrical power, thereby optimizing overall engine efficiency. The engine performance is enhanced with boosting mode where the electric motor accelerates the turbocharger independently of exhaust flow, effectively reducing turbo lag and provides immediate boost at low engine speeds. This feature also improves high altitude performance. Conversely, in generating mode, the electric turbocharger recovers energy from exhaust gases depending on engine operating conditions, converting it into electrical energy for battery recharging. Advanced control systems enable real-time adjustments to boost pressure and airflow in response to dynamic driving conditions, maximizing engine efficiency. Simulation studies
Borle, Shraddha, Prasad, Lakshmi, Couvret, Sebastien, Fournier, Hugo, Chenuet, Laurent
Effect of EGR and Ethanol additive on Performance and Emission Characteristics of Diesel Engine Fuelled with Rubber Seed Biodiesel Blends2025-28-0224To be published on 11/06/2025
Alcohols are being considered as an alternative to traditional fuels for compression ignition engines due to their oxygen content and biomass origin. While alcohols have lower cetane numbers, making them more suitable for premixed combustion, they are also a promising option for reducing exhaust emissions in internal combustion engines through methods like exhaust gas recirculation. In this study, we investigate and improve the performance of a single-cylinder, four-stroke diesel engine by introducing ethanol into the intake port during the intake stroke. The main fuels used were diesel and rubber seed biodiesel, which were injected directly into the combustion chamber. The results showed that increasing the amount of ethanol combined with rubber seed biodiesel and his EGR by 10% improved brake thermal efficiency and reduced NOX emissions. The timing and duration of ethanol injection are optimized for dual fuel operation. The highest brake thermal efficiency for a 20% ethanol energy
Saminathan, Sathiskumar, G, Manikandan, Bungag, Joel Quendangan, T, Karthi
Reduction in Product Development Time by Field-to-Lab Simulation2025-28-0282To be published on 11/06/2025
KEYWORDS: Flywheel Inertia, Clutch system, Gear Box, Tractor application, Instrumentation, data analysis, Design and develop new test methodology. ABSTRACT: Puddling is a crucial process in rice cultivation, involving the preparation of the soil in a flooded field to create a soft, muddy seedbed. There are two classifications for puddling: full cage and half cage. Full cage puddling involves replacing the rear wheels of the tractor with steel paddle wheels, which are used to till the rice paddies directly without any additional implement. In the half cage puddling, the rear wheels remain on the tractor, and a smaller cage or paddle wheel is attached to the outside. Considering the field size, the operator often releases the clutch very quickly after a speed or direction change. This generates torque spikes, which are harmful to Transmission Gears and Clutches. This can lead to gear teeth bending fatigue failure due to repeated higher bending stresses. In this paper, a study related to
Pathan, Irfan Hamidulla, Bardia, Prashant
Computational Fluid Dynamics (CFD) Analysis of Turbocharger Aerodynamics and Thermal Behaviour in Automotive Application2025-28-0229To be published on 11/06/2025
Turbocharging has emerged as a crucial technology for enhancing the performance and efficiency of internal combustion engines (ICEs) in modern vehicles. As the demand for lower fuel consumption and reduced emissions increases, turbochargers enable engine downsizing while maintaining or improving power output. This research work analyses the performance of turbocharging systems, focusing on their working principles, design considerations, performance evaluation, and efficiency optimization in automotive applications. The research begins with an overview of turbocharger fundamentals, detailing key components such as the turbine, compressor, intercooler, and wastegate, along with their respective functions. It examines how exhaust gas energy drives the turbine, which in turn compresses intake air to enhance engine efficiency. Furthermore, this work explores the influence of turbocharger selection on engine power, fuel economy, and emissions. Additionally, this research investigates
Chandrashekar, B. Aditya, Bhaduria, Abhishek
Full cycle CFD modeling of a Wankel engine for UAV applications2025-32-0013To be published on 11/03/2025
Rotary engines represent a very attractive solution for uncrewed aerial vehicle applications (UAV) and portable power generation thanks to their compact size, high power-to-weight ratio, reduced moving parts and possibility to operate with multiple fuels. Despite very promising, such technology needs to be improved in different areas to reach same efficiency and lifespan of reciprocating IC engines. In particular, fuel consumption is affected by the heat losses resulting from the high combustion chamber surface-to-volume ratio and by the unfavorable interaction between rotor and stator slowing down the flame propagation. Within this context, computational fluid dynamics (CFD) represent a valuable tool to study and design Wankel engines, understanding how fuel efficiency is affected by the complex interplay between combustion chamber design, flame propagation, flow and turbulence distribution. This work presents a CFD methodology for the simulation of gas exchange and combustion in
Lucchini, Tommaso, Gianetti, Giovanni, Ramognino, Federico, Cerri, Tarcisio, Marmorini, Luca, Buttitta, Marco
Hydrogen-Assisted Renewable Fuels RME and HVO in the Compression-Ignition Engine2025-32-0048To be published on 11/03/2025
The article presents the research results on performance, thermodynamic parameters, and toxic exhaust emissions from the combustion in a compression-ignition engine fueled by the hydrotreated vegetable oil (HVO) or the rapeseed methyl ester (RME), both with hydrogen addition. Furthermore, regular diesel fuel was used to obtain the reference data for comparing HVO, RME, and diesel fuel. Hydrogen was injected into the intake manifold of a CI engine with a compression ratio of 17. Typically, diesel fuel combustion in a CI engine initiates through its self-ignition, usually simultaneously occurring at many points across the engine cylinder. Hydrogen, as a very chemically reactive substance, can promote pre-ignition reactions and accelerate flame kernel formation, shortening the ignition lag. This is crucial in the case of the smooth running of the compression-ignition engine. Hydrogen was added at amounts not exceeding 7% by volume as regards air sucked into the engine cylinder. The heat
Szwaja, Stanislaw, Juknelevicius, Romualdas, Pukalskas, Saugirdas, Rimkus, Alfredas, Szymanek, Arkadiusz
Experimental and kinetic study of methane blending on the laminar combustion and emission characteristics of ammonia under various oxygen contents at high temperature and pressure2025-32-0060To be published on 11/03/2025
As a carbon-free fuel, ammonia is one of the alternatives to traditional fossil fuels, but its combustion characteristics are poor, and it is usually optimized by blending methane and increasing oxygen content. However, there are few relevant studies under different conditions under high temperature and high pressure conditions. In this study, the laminar burning velocities (LBV) and flame instability of NH3/CH4/O2/N2 mixtures at high initial temperature (T), high initial pressure (p), various oxygen contents (Ω) and methane energy ratios (α) are analyzed using a constant volume combustion chamber (CVCC). According to numerical simulation, how various oxygen contents and methane energy ratios affect the combustion characteristics of NH3/CH4/O2/N2 mixtures and NOx emission is analyzed. The results show that LBV is positively correlated with T、α、and Ω, and negatively correlated with p. Markstein length (Lb) does not change significantly with T, but increases with α and decreases with p
YU, Yuantao, Dai, Zhizhuo, Hou, Chunlei, Ye, Mingyuan, Zhang, Xiaolei, Cui, Zechuan, Yin, Shuo, Nishida, Keiya
Numerical analysis of combustion stability and efficiency improvement in ammonia engines utilizing Passive Turbulent Jet Ignition (PTJI)2025-32-0049To be published on 11/03/2025
Ammonia, recognized as a carbon-neutral fuel, is considered a promising candidate for next-generation engine applications. Nevertheless, its combustion performance is constrained by its low flame speed and prolonged ignition delay, leading to limitations in combustion stability and efficiency across high-speed/high-load and low-speed/low-load operating conditions. Notably, incomplete combustion resulting from limited residence time is a critical issue at high speeds, while ignition instability and low combustion temperatures pose significant challenges at low speeds. To overcome these limitations, Passive Turbulent Jet Ignition (PTJI) system has been proposed. By promoting turbulent mixing within the combustion chamber and employing multiple ignition strategies, PTJI demonstrates potential for mitigating the inherent drawbacks associated with ammonia combustion. This research investigates the optimization of a PTJI system for ammonia-fueled engines through a three-phased methodology
Ju, Kangmin, Kang, Hyun-Ung, Kim, Jeong Hyeon
Effect of In-cylinder Hydrogen Mixture Formation on Hydrogen Combustion2025-32-0065To be published on 11/03/2025
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 Automatic Calibration System for PFI Engines2025-32-0084To be published on 11/03/2025
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
Advanced 3D Simulations of a Four-Stroke High-Performance Engine Valvetrain for the Analysis of the Mechanical Stresses and Energy Losses2025-32-0010To be published on 11/03/2025
Enhancing the performance of naturally aspirated 4-stroke engines relies heavily on improving trapping efficiency, increasing maximum engine speed, and reducing friction losses. In this regard, the valvetrain plays a critical role. Achieving high volumetric efficiency at higher engine speeds necessitates very steep valve opening and closing ramps, making this aspect pivotal in the design process. At high engine speeds, significant dynamic phenomena arise, including valve float, during the lift phase, and valve bounce, during the closing phase. These effects not only induce substantial modifications to the valve lift curve but also increase the mechanical stress on critical components such as the valve and rocker arm, thereby elevating the risk of failure. Moreover, the timing system substantially contributes to overall engine losses due to frictional energy dissipation, which results from the numerous interactions between moving components. The present works aims at developing a
Tarchiani, Marco, Pizzicori, Alessio, Raspanti, Sandro, Romani, Luca, Meli, Enrico, Ferrara, Giovanni, Trassi, Paolo
Diesel Combustion Parameter Estimation via Machine Learning – A Comparative Study2025-32-0041To be published on 11/03/2025
This paper presents an analysis of distinct approaches for data-driven combustion parameter estimation for Diesel engines. Thereby, characteristic quantities are modeled by a set of selected regression models, and via a convolutional neural network (CNN). While the former use settings from the Engine Control Unit (ECU) as input, the latter works by processing the raw crankshaft vibration signal. The central point of this study is a broad evaluation of data-driven modeling for Diesel combustion. This includes whether using a signal recorded from individual combustion cycles achieves better representation of the target values than using ECU settings which cannot reflect unforeseeable, stochastic phenomena within the combustion chamber. This was evaluated by assessing predictions of six combustion characteristics: CA10, CA50, CA90, Peak-Firing-Pressure (PFP), Combustion Duration (CD), and Ignition Delay (ID). In two series of experiments it is established that individual cycle data
Ofner, Andreas Benjamin, Sjoblom, Jonas, Geiger, Bernhard, Haghir Chehreghani, Morteza
Visualization Study on the Combustion Characteristics of Diesel-Ignited Ammonia/Methane Mixtures2025-32-0054To be published on 11/03/2025
The application of ammonia fuel in engines can significantly reduce carbon emissions, serving as a crucial method for achieving carbon neutrality. However, its potential is hindered by the challenges of ammonia's difficulty in ignition and slow combustion rate. An effective solution to these drawbacks is the blending of methane into ammonia mixtures and the use of a small amount of diesel for ignition. This study investigates the effects of mixture temperature, pressure, and gas composition (N2/NH3/CH4) on diesel spray characteristics using a constant volume combustion chamber (CVCC). Additionally, pressure measurements and visual observations of the combustion process of diesel-ignited Air/NH3/CH4 mixtures under various conditions were conducted using a rapid compression and expansion machine (RCEM). Through the analysis of spray characteristics, a more detailed explanation of the effects of different conditions on combustion behavior is provided. Experimental results reveal that, at
Yin, Shuo, Dai, Zhizhuo, Zhou, Qingxing, Cui, Zechuan, Zhang, Xiaolei, Ye, Mingyuan, Ren, Yifang, Wang, Zhanpeng, Nishida, Keiya
Development of a Combined Injection and Ignition Unit for a Gas Engine with Direct Hydrogen Injection Integrated into the Standard Spark Plug Access Hole2025-32-0059To be published on 11/03/2025
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
Ca Additive and In-cylinder Condition on Promotion of Abnormal Combustion in Supercharged SI Engine2025-32-0004To be published on 11/03/2025
　The downsizing engine is popular in the field of SI engine. However, one of the problems is the abnormal combustion so called LSPI. 　A lot of researchers have been reported about the mechanism of LSPI. One of the sources of LSPI would be the lubricating oil droplet in cylinder. To avoid LSPI, it has been adjusted the ingredients of oil additive in lubricating oil. However, many kinds of fuels will be adapted to the SI engine on the point of CO2 emission in the future. So, it would be needed that the mechanism of LSPI would be cleared essentially. It has been reported that the ingredients of oil additive strongly effect on the occurring the LSPI. There are two information in our previous research. First, the data shows that frequency of abnormal combustion is 1/10 of frequency of scattering lubricating oil from the piston crown. 　Seconds, autoignition timing of scattering lubricating oil is almost at ATDC, however several its autoignition proceed the timing for BTDC continuously. 　Here
kitano, Kaito, Tanaka, Junya
Design optimization and calibration of a single-cylinder, motorcycle engine for integration into a novel Formula SAE electric hybrid powertrain2025-32-0045To be published on 11/03/2025
The Formula SAE competitions often drive changes in the automotive research field by developing, implementing and emphasizing new technologies for both on-road and on-track applications and by training future engineers, mechanics, logistics and administrative personnel. In this work, the adaptation of a motorcycle, single-cylinder engine for the installation in an electric hybrid car for Formula SAE races is described, focusing on the design of intake and exhaust parts and on the development of the fully open-access Engine Control Unit code. In the first part of the work, the 1-D model of the engine is developed and used to design the intake and the exhaust parts needed to make the Formula Student car rules compliant. In particular, the intake manifold and the intake ducts have been designed with the assistance of the engine model to optimize the engine response under transient conditions and to maximize the power. On the other hand, the exhaust line was designed to increase the
Brusa, Alessandro, Fabbri, Pietro, Shethia, Fenil, Bassani, Davide, Petrone, Boris, Cavina, Nicolo
Effect of Plasma-Assisted Ignition on Combustion and Emission Characteristics of Two Stroke Engines with Different Fuels2025-32-0030To be published on 11/03/2025
The 2-stroke opposed piston engine(2OPE) is attracting attention for its potential to achieve higher theoretical thermal efficiency due to its unique combustion chamber design. 2OPE has twice stroke/bore ratio compared to that of conventional 2-stroke engines, which reduces cooling losses, thereby enhancing output power density. However, like other 2-stroke engines, the 2OPE faces challenges such as fuel short-circuiting and scavenging loss, which historically limited the development of 2-stroke engines. Due to the insufficient scavenging process, the residual gas remains higher than 4-stroke engine. Although the residual gas helps maintain higher in-cylinder temperature that accelerate the fuel evaporation, the reduced fresh air supply leads to incomplete combustion and increasing carbon monoxide (CO) and hydrocarbon emission (HC). Under that condition, the minimum ignition energy increases sharply and leading to slower combustion. Plasma-assisted ignition (PAI) is considered as a
Liu, Jinru, Yamazaki, Yoshiaki, Otaki, Yusuke, Kato, Hayato, Kobayashi, Daichi, Umegaki, Tetsuo, Asai, Tomohiko, Iijima, Akira
Study of Combustion Characteristics of a Two-stroke Opposed Piston Engine using Low-octane Fuels2025-32-0028To be published on 11/03/2025
Various fuels are being considered as the next generation of carbon neutral fuels, including methanol, ethanol, and SAF. These have widely different ignition properties. Methanol and ethanol are high-octane fuels, so there are no major problems with their use in gasoline engines. However, SAF is a hydrocarbon with a large molecular weight, so it has a fundamentally low octane rating and is not easy to use in SI engines. In order to put carbon-neutral fuels of various properties into practical use, it is effective to develop a technology that allows fuels with low octane to be operated in SI engines. Therefore, in this study, basic research was conducted on the combustion of fuels with low octane using PRF fuel in opposed-piston engines. Opposed piston engines are characterized by their light weight due to the absence of a cylinder head, low S/V ratio due to the ultra-long stroke, reduced cooling loss due to the long stroke, and reduced vibration due to the offsetting of the
Yamazaki, Yoshiaki, Okawara, Ikumi, Liu, Jinru, Iijima, Akira
Optimum Bore-to-Stroke Ratio for a Flathead Uniflow Two-Stroke SI Engine and its Impact on Different Fuels2025-32-0024To be published on 11/03/2025
This numerical study investigates a spark-ignited, two-stroke engine employing uniflow scavenging, flathead cylinder head design, and an exhaust valve system to identify the optimal bore-to-stroke (B/S) ratio for maximizing brake efficiency at fixed displacement. A single-cylinder prototype engine was constructed, and its experimental data validated a 1D GT-SUITE simulation model. This validated model was then utilized to simulate a full-scale, 1.5-liter displacement, horizontally opposed four-cylinder engine with supercharger-assisted boosting, intended for small aircraft propulsion. The simulations explored a range of B/S ratios from undersquare (0.7) to oversquare (1.5), maintaining a consistent brake power output of 60 kW at 3000 rpm and lambda 0.9. Results showed that increasing the B/S ratio enhanced brake efficiency from 26.0% at B/S=0.7 to 27.0% at B/S=1.5, largely due to reduced frictional losses attributed to shorter stroke and lower piston speeds, decreased heat transfer
Zanchin, Guilherme, Hausen, Roberto, Fagundez, Jean Lucca, Lanzanova, Thompson, Martins, Mario
Effect of hydrogen injection timing in a compression ignition engine operating in hydrogen diesel dual fuel mode2025-32-0051To be published on 11/03/2025
Stringent European CO2 emission regulations have stimulated the development of alternative technologies such as Dual Fuel (DF), which involves partially replacing fossil fuel with a low-carbon alternative. Hydrogen represents an ideal candidate for DF due to its properties, including the absence of carbon, high flame propagation speed, and high diffusivity. This study analyzes the combustion and performance of a 1L, naturally aspirated, three-cylinder in-line compression ignition off-road engine with a 17.5:1 compression ratio, originally equipped with a conventional diesel system and modified for diesel-hydrogen dual fuel operation. The conversion involved installing three PFI injectors in the intake manifold for hydrogen injection, attempting to minimize the volume between the intake valve and injector tip. Tests were conducted at a fixed engine speed of 2000 rpm, varying the engine load from 30% to 85% of maximum torque. The diesel contribution was maintained at 10%, while hydrogen
Rossetti, Salvatore, Mancaruso, Ezio
Order Dispersion Method by Crankpin Arrangement into Enhancements of Structural Reliability and Sound Quality for V8 Outboard Motor2025-32-0021To be published on 11/03/2025
This paper provides insight into the utility of the low vibration crankshaft for outboard motors, especially focuses on the enhancements of the structural reliability of the crankshaft and the sound quality of the outboard motor. In previous research, we developed the crankshaft which can balance by itself for V8 outboard motor with V bank angle of 60 degrees. We specifically showed the theoretical basis of the balancing and the measurement results of actual vibration levels on boat. Meanwhile, note that the crankshaft has a distinctive structure of crankpin offset angle of 60 degrees, so that combustion interval becomes unequal. As to the combustion, however, we just mentioned the effects on the engine output performance, not the practicality. In this paper, we clarify the following two benefits of unequal interval combustion in terms of the structural reliability and the sound quality. One is that the order dispersion resulting from unequal interval combustion can reduce the
Takanishi, Kentaro, Muramatsu, Hideta, Kondo, Takashi, Naoe, Gaku
Advanced Multi-Fidelity Simulation of Piston Oil Jet Cooling in High-Performance Engines2025-32-0081To be published on 11/03/2025
The development of next-generation hydrogen-fueled engines introduces critical challenges related to thermal solicitations within the combustion chamber, particularly in high-performance applications. To address the extreme temperatures encountered, effective piston cooling strategies, such as oil jet impingement, are essential. The ability to accurately predict the expected thermal stress and prevent failure is crucial. However, numerical simulations often come with significant computational costs. This paper presents a comprehensive multi-fidelity modeling approach to predict the thermal behavior of pistons under these demanding conditions. The model integrates a simplified 3D thermal representation of the piston, a lumped-parameter mechanical model of the piston-liner assembly, and convective boundary conditions obtained at various levels of fidelity, from high-level CFD simulations to literature correlations. Additionally, the study examines the influence of different approaches to
Sassoli, Andrea, Romani, Luca, Ferrara, Giovanni, Paolicelli, Giovanni, Balduzzi, Francesco
Investigating the Influence of Intake Runner Configuration on Scavenging and Combustion Processes in Elliptical Rotor Engines2025-32-0089To be published on 11/03/2025
Elliptical rotor engines (ERE), also known as X-engines, feature intake and exhaust ports located on the rotating rotor. As the rotor turns, these ports traverse the entire combustion chamber, sequentially completing the scavenging process in three distinct combustion chambers through coordination with the cylinder walls. This intake and exhaust characteristic significantly differs from the characteristic found in traditional Wankel rotor engines. This study established an optical elliptical rotor engine to obtain the in-cylinder flow field by using Particle Image Velocimetry (PIV) and constructed a CFD model based on the experimental results. Then the effects of two different intake runners on the scavenging and combustion process of ERE were investigated. The results indicated that: Due to structural limitations, the prolonged intake port opening duration results in significant gas backflow during the intake process. The curved intake runner exhibits a higher turbulent kinetic energy
Qin, Jing, Wang, Yingbo, Pei, Yiqiang, Yao, Dasuo, Deng, Xiwen
Measurement of the liquid fuel film on the combustion chamber wall of a gasoline engine using a novel capacitance sensor2025-32-0018To be published on 11/03/2025
During a cold start and warm-up operation of an SI gasoline engine, a liquid fuel film is formed on the intake port and piston walls. The liquid fuel film attached to the wall increases exhaust unburned HC, particulate matter (PM) emissions, and oil dilution. It is essential to investigate the formation process of the fuel liquid film to reduce exhaust emissions and improve thermal efficiency. Compact fuel film measurement sensors are required for application in the production engine measurement. In this study, a liquid film sensor detecting changes in capacitance due to the liquid film has been developed. The newly developed liquid film sensor was installed and demonstrated into the combustion chamber wall of a single-cylinder gasoline engine. As a result, the liquid film behavior on the combustion chamber wall was successfully detected.
Kuboyama, Tatsuya, Nakajima, Takeru, Moriyoshi, Yasuo, Takayama, Satoshi, Nakabeppu, Osamu
Development of CAE Technology for the Design Support of Piston Pin Circlip2025-32-0015To be published on 11/03/2025
This study focuses on the technology for establishing design criteria for the piston pin circlip (hereinafter referred to as "circlip"), which is a component that holds the engine piston pin. The circlip is assembled into the piston by compressing it to the size of the piston circlip groove. However, in high-revving engines, the inertia forces caused by engine rotation can cause the circlip to disengage from the groove, potentially leading to the piston pin falling out and damaging the engine. To prevent this, it is possible to compress the circlip more and increase the reactive force acting on the groove to prevent falling out. However, this countermeasure raises concerns about the deterioration of the assemblability of the circlip. Therefore, it is necessary to establish evaluation criteria that prevent the circlip from disengaging and deteriorationg the assemblability of the circlip. To enable appropriate design of the circlip during the engine specifications review phase, we
Ishizuka, Atsushi, Watanabe, Naoto
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
Impact of Oil Composition on Pre-Ignition in a Hydrogen Engine04-18-03-001810/10/2025
Pre-ignition (PI) is a common issue in internal combustion engines (ICE) with spark ignition. While the various causes have been identified with conventional fuels (such as gasoline or gasoline blends), the causes with hydrogen in ICE are not yet fully understood. This article presents the results of investigations into the influence of seven different lubricating oils on PI in a single-cylinder hydrogen research engine. The variation of two different parameters at two engine speeds were investigated: load and air/fuel mixture. For both variations, the tests start at the same conditions and run until the operating limit of the engine is reached (peak firing pressure, or maximum intake manifold pressure). The PI and knocking PI are investigated, while classifying them according to the peak cylinder pressure. It has been observed that enleanment above λ = 2.4 can lead to higher PI rates, while simultaneously reducing the knocking PI. During the load sweep at 2000 1/min, the highest
Pehlivanlar, Benjamin, Torkler, Michael, Fischer, Marcus, Göbel, Christoph, Pischinger, Stefan, Maulbetsch, Theo, Nübling, Fritz, Neumann, Stephan
An Investigation into the Impact of Cylinder Count on the Efficiency of Opposed Piston Two-Stroke Compression Ignition Engines03-18-06-003710/09/2025
The gas exchange process of opposed piston two-stroke (OP2S) diesel engines is primarily driven by the pressure differential between the intake and exhaust, making them susceptible to cylinder-to-cylinder crosstalk, and therefore to cylinder count. This study examined how cylinder count influences brake efficiency in OP2S engines. Using an experimentally validated 1D engine model, three architectures, ranging from two to four cylinders, were created and simulated across their full operating ranges. To isolate the impact of cylinder count, all configurations employed identical cylinder and port geometries, and identical but scaled electrically assisted turbocharger based airpaths. The engines were also controlled to consistent trapped conditions at a given operating condition, resulting in comparable closed-cycle efficiencies. Comparisons were then made using both scaled electrified airpaths and by assuming isentropic airpath work, to assess the impact of airpath efficiency on the
Vorwerk, Erik Scott, Prucka, Robert, Lawler, Benjamin, Huo, Ming
Effect of Flow Speed and Turbulence on Methane Combustion in a Rapid Compression Machine2025-01-039310/07/2025
Recent experimental work from the authors’ laboratory demonstrated that applying a boosted current ignition strategy under intensified flow conditions can significantly reduce combustion duration in a rapid compression machine (RCM). However, that study relied on spark anemometry, which provided only localized flow speed estimates and lacked full spatial resolution of velocity and turbulence near the spark gap. Additionally, the influence of turbulence on combustion behavior and performance across varying flow speeds and excess air ratios using a conventional transistor-controlled ignition (TCI) system was not thoroughly analyzed. In this study, non-reactive CFD simulations were used to estimate local flow and turbulent velocities near the spark gap for piston speeds ranging from 1.2 to 9.7 m/s. Simulated local velocities ranged from 0.7 to 96 m/s and were used to interpret experimentally observed combustion behavior under three excess air ratios (λ = 1.0, 1.4, and 1.6). Combustion was
Haider, Muhammad.Shaheer, Jin, Long, Yu, Xiao, Reader, Graham, Zheng, Ming
Approaches for Mechanical Development and Validation of Hydrogen Internal Combustion Engines2025-01-039810/07/2025
Hydrogen Internal Combustion Engines (H2 ICEs) are seen as a viable zero-emission technology that can be implemented relatively quickly and cost-effectively by automotive manufacturers. The changed boundary conditions of a hydrogen-fueled engine in terms of mechanical and thermal aspects require a review and potential refinement of the design especially for the 'piston bore interface' (liner honing, ring and piston design) but also for other engine sub-systems, e.g. the crankcase ventilation system. The influence of oil entry into the combustion chamber is even more important in hydrogen engines due to the risk of oil-induced pre-ignition. Therefore, investigations of the interaction between friction, blowby and oil transfer into the combustion chamber were performed and are presented in this paper. During the investigations, experimental tests were carried out on a single-cylinder engine ('floating liner') and on a multi-cylinder engine. The 'floating liner' concept allows the crank
Plettenberg, Mirko, Gell, Johannes, Grabner, Peter, Gschiel, Kevin, Hick, Hannes
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
CFD Analysis of Knocking in Hydrogen-Fueled Spark-Ignition Engines with Large Eddy Simulation and Conjugate Heat Transfer2025-01-038910/07/2025
In the pursuit of a carbon-neutral society, hydrogen-fueled power generation engines are gaining considerable attention. However, knocking remains a significant problem that hinders efficiency improvements in hydrogen-fueled spark-ignition (SI) engines. In particular, the large displacement engines, such as those used in cogeneration and distributed energy sources, often face issues with knocking. This is because, with a larger bore and lower rotational speed, there is a higher risk of auto-ignition occurring before the flame has spread throughout the combustion chamber. Knocking is a complex phenomenon influenced by several interrelated physical factors:1) Flow: the non-uniform distribution of fuel concentration and flow velocity within the cylinder; 2) Combustion: the non-uniform propagation of flames affected by the mixture's concentration and flow velocity distribution; 3) Heat Transfer: the non-uniform temperature of the unburned mixture resulting from the temperature distribution
Nomura, Kazutoshi, Suzuki, Keita, Imamori, Yusuke, Fuse, Azusa, Oda, Yuji, Nakano, Hiroki, Tsujimura, Taku, Suzuki, Yasumasa
CFD and FE Toolset for Predicting Structural Temperatures in a Hydrogen Internal Combustion Engine2025-01-038310/07/2025
Hydrogen has been identified as a promising decarbonization fuel in internal combustion engine (ICE) applications in many areas including heavy-duty on- and off-road, power-generation, marine, etc. Hydrogen ICEs can achieve high power density and very low tailpipe emissions. However, there are challenges; designing systems for a gaseous fuel with its own specific mixing, burn rate and combustion control needs, which can differ from legacy products. Being able to determine the thermal distribution and temperatures of the power cylinder components has always been critical to the design and development of ICE. SAE-2023-01-1675 [1] presented an analytical FE-based tool, and validation using both FE and CFD methods for a Euro VI HD Diesel engine converted to operate on hydrogen gas using direct injection. In this study, updated methods and investigations are presented for Hydrogen ICE including applicability of the Woschni heat transfer correlation, use of CFD thermal wall functions and a
Bell, David J., Shapiro, Evgeniy, Turquand d Auzay, Charles, Hernandez, Ignacio, Hynous, Jan, Kohutka, Jiri, Osborne, Richard, Penning, Richard, Tomiska, Zbynek
A Study of Variables Affecting Piston Skirt Loads on the Oppossed Piston Two Stroke Diesel Engine2025-01-049909/16/2025
A kinematic model of primary piston motion was developed along with a simplified combustion model for the purpose of evaluating various factors that could impact the piston skirt thrust loads of an Opposed Piston Two Stroke Diesel engine. The assessment considered connecting rod length, wrist pin mass, peak cylinder pressure, indicated torque, and wrist pin offset. The results show that small changes in connecting rod length could realize significant improvements in piston skirt friction as well as increased engine performance. The results indicate that small increases in overall engine width should be considered when optimizing for reduced oil consumption and enhanced piston skirt lubrication.
Srodawa, John
Enhancing Robustness of Electro-Hydraulic Brake-by-Wire Actuators via Linear Active Disturbance Rejection Control2025-01-034109/15/2025
In recent years, motorsport has increasingly focused on environmental concerns, leading to the rise of hybrid and fully electric competitions. In this scenario, electric motors and batteries take a crucial role in reducing the environmental impact by recovering energy during braking. However, due to inherent limitations, motors and battery cannot fully capture all braking power, necessitating the use of standard friction brakes. To achieve an efficient balance between electric motors and friction brakes, the brake pressure can no longer be directly controlled by the driver. Instead, it must be computed by the Vehicle Control Unit (VCU) and sent to a smart actuator, i.e. the Brake-By-Wire (BBW), which ensures that the required pressure is applied. The standard approach to achieve precise pressure control is to design a nested Proportional-Integral-Derivative (PID) control architecture, which requires an accurate nominal model of the system dynamics to meet the desired tracking
Gimondi, Alex, Dubbini, Alberto, Riva, Giorgio, Cantoni, Carlo
The Challenges of Measuring Residual Brake Drag using Different Test Apparatuses and Methods to Mitigate Inaccuracies2025-01-034309/15/2025
As automotive manufacturers have tried to set themselves apart by reducing emissions, and increasing vehicle range/fuel economy by eliminating any energy loss from inefficiencies on the vehicle, the brake corners have been an area of interest to reduce off-brake torque to zero in all conditions. Caliper designers can revise some attributes like piston seal grooves, and pad retraction features to reduce drag, but even if a caliper is designed perfectly in all aspects, trying to measure it in a reliable and repeatable manner proves to be difficult. There are many ways to measure brake drag all with ranging complexity. Some of the simplest measurements are the most repeatable, but it excludes the majority of the vehicle inputs. The most vehicle representative testing requires the most complex equipment and comes with the most challenges. This paper will focus mainly on the different ways residual brake drag can be measured, the benefits and challenges to each of them, the problems trying
Retting, Joshua
Development of a Laboratory Brake for a Flywheel Mass Test Rig for Variable Pad Sizes and Shapes with a Force Distribution Unit for Ideal Contact Pressure and a Topography Measurement System for In-Situ Recording of Surface Changes and Wear2025-01-033109/15/2025
Pin-on-disk tribometers are used to determine the frictional behaviour and boundary layer dynamics of material pairings. Material pairings are examined under defined conditions in order to reason about the friction behaviour and wear. Pairings for real brake systems with larger pad sizes can be tested on flywheel mass test rigs in order to provide proof of suitability. This is mainly due to a lack of knowledge about the scaling behaviour of friction linings. The Department of Machinery System Design at TU Berlin has combined the classic approach of a pin-on-disk tribometer with a flywheel mass test rig (up to 12.78 kgm2) and thus set up a laboratory brake on which material pairings with different pad shapes and sizes (up to 48 cm2) can be examined. The flywheel mass test rig consists of an adjustable DC-motor that drives a shaft on which variable flywheel masses and brake disks can be installed. The variability allows for different kinetic energies at different friction speeds. The
Heuser, Robert Michael, Rosenthal, Tobias Richard, Wiest, Daniel Christian, Meyer, Henning Jürgen
Experimental Analysis of Enhanced Scavenging Efficiency in Hydrogen-Powered Internal Combustion Engines for Heavy-Duty Applications2025-24-005609/07/2025
The purpose of this work is to highlight the benefits of improved scavenging efficiency for premixed, lean-burn, spark-ignited heavy-duty engines fueled by hydrogen. Scavenging efficiency measures the effectiveness of replacing exhaust gases with fresh air (or an air-fuel mixture) within the cylinder of an internal combustion engine. Enhanced scavenging efficiency reduces residual gas content and increases the proportion of fresh air, resulting in a cooler local mixture temperature. Additionally, it improves heat dissipation within the combustion chamber, cooling potential hotspots and allowing for earlier injections with fewer restrictions due to combustion anomalies, particularly pre-ignitions. To increase scavenging efficiency in a 4-stroke internal combustion engine, valve timing adjustments were made by introducing a valve lift profile with greater overlap of the exhaust valve closing and the inlet valve opening sequences. Additionally, a high-efficiency turbocharger was used to
Schuette, Christoph, Borg, Jonathan, Giordana, Sergio, Rapetto, Nicola
Flexible an Low Cost Fuel Consumption Prediction in Heavy-Duty Vehicles Using Machine Learning2025-24-012109/07/2025
This study presents a novel approach for predicting fuel consumption in heavy-duty vehicles using a Machine Learning-based model, which is based on feedforward neural network (FFNN). The model is designed to enhance real-time vehicle monitoring, optimize route planning, and reduce both operational costs and environmental impact, making it particularly suitable for fleet management applications. Unlike traditional physics-based approaches, the FFNN relies solely on a refined selection of input variables, including vehicle speed, acceleration, altitude, road slope, ambient temperature, and engine power. Additionally, vehicle mass is estimated using a methodology presented elsewhere and is included as an input for a better generalization of the consumption model. This parameter significantly impacts fuel consumption and is particularly challenging to obtain for heavy-duty vehicles. Engine power is derived from both engine torque and speed (RPM), ensuring a direct relationship with fuel
Vicinanza, Matteo, Pandolfi, Alfonso, Arsie, Ivan, Giannetti, Flavio, Polverino, Pierpaolo, Esposito, Alfonso, Paolino, Antonio, Adinolfi, Ennio Andrea, Pianese, Cesare, Frasci, Valentino
Methodology for the Study of Hydrogen Combustion in an Optical Spark Ignition Engine2025-24-006209/07/2025
The use of hydrogen as a fuel in internal combustion engines represents a promising alternative for reducing CO2 emissions. To optimize its efficiency and better understand the phenomena associated with its combustion, it is essential to have advanced visualization techniques for a better understanding of the processes involved. This paper presents the methodology used in the development of an optical engine for the study of hydrogen combustion, designed from a 454cc single-cylinder engine. The configuration of the optical system is described, which includes the use of high-speed cameras to capture the spark plug activation as well as the flame propagation in the combustion chamber. The engine has two optical accesses, one through the piston and one at the top of the cylinder that allows side viewing of the combustion chamber. In addition, the experimental procedure that alternates combustion cycles with motoring cycles, the determination of the air-hydrogen ratio with which the engine
Pastor, Jose V., Novella, Ricardo, Tejada, Francisco J., Cáceres-Carías, José
Water Injection Effects on a Heavy-Duty Hydrogen Spark Ignition Engine2025-24-005009/07/2025
Hydrogen engines have gained interest recently, as they present a promising alternative for decarbonizing heavy-duty transport, aligning with carbon neutrality regulations. This study investigates the effects of inlet manifold water injection on a heavy-duty hydrogen-fueled spark ignition single-cylinder engine, focusing on moderating abnormal hydrogen combustion and its impact on performance, thermal efficiency, and exhaust emissions. Water injection has been identified as a potential solution to mitigate the challenges associated with hydrogen combustion, such as pre-ignition and knock, by reducing the reactivity of the mixture (lowering temperature and increasing the dilution). The lower reactivity of the mixture allows running richer lambdas or higher compression ratios without spontaneous preignition, mitigating boosting requirements for full load and transient performance. Experimental results demonstrate that water injection significantly improves engine performance, thermal
Peñin Garcia, Alfonso Jose, Valls Claramunt, Carles, Rivas, Manuel, Birnstingl, Johannes, Wieser, Martin, Martin, Jaime, Novella, Ricardo
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
Numerical Analysis of the Combustion Process in a Pre-Chamber Marine Engine Fueled with Ammonia-Hydrogen Mixtures2025-24-002109/07/2025
Ammonia and hydrogen, as carbon-neutral fuels, possess the potential to play a crucial role in the decarbonization of the mobility sector. This research examines the optimization of the combustion process in a marine spark-ignition engine through the use of a passive pre-chamber. The study has been carried out using computational fluid dynamics (CFD) models. Considering a hydrogen content in the fuel blend of 15% by volume, at a fixed equivalence ratio equal to 0.8, two different nozzle diameters have been tested, and the optimal spark timings have been identified. Then, the effect of different hydrogen amounts in the fuel mixture on the engine’s performance and emissions has been assessed. An optimal spark timing of 712 CAD has been found for both 3 mm and 5 mm nozzles at the specified operating point. The 5 mm nozzle provides slightly higher IMEPH and gross efficiency, with minimal impact on emissions. Reducing hydrogen in the fuel blend from 15% to 10% lowers IMEPH from 31 to 12 bar
D'Antuono, Gabriele, Lanni, Davide, Galloni, Enzo, Fontana, Gustavo
Exploring the Emission Spectrum of Pure Hydrogen Combustion in Spark Ignition Engines: A Comprehensive Experimental Study2025-24-005109/07/2025
Hydrogen internal combustion engines (H2ICE) have shown enormous potential for zero-carbon emissions, aligning with the European zero-carbon targets in 2050. Adopting hydrogen as a zero-carbon fuel offers a time- and cost-effective approach to directly replacing carbon-based and fossil fuel-powered ICEs. The study aims to provide comprehensive data on the H2ICE engine during steady-state operations of a single-cylinder spark ignition engine with a direct hydrogen injection system. It focuses on emissions, including carbon monoxide (CO) and unburnt hydrocarbons (HC), utilising ultra-fast analysers positioned close to the exhaust valves to minimise signal delay. Particulate matter (PM) emissions are also measured to evaluate the potential for zero-carbon emissions from the H2ICE. Additionally, NO and NO2 emissions are analysed against air-fuel ratios (AFR) to estimate combustion temperature and NOx mechanisms. Water vapour and oxygen emissions are captured to assess their quantities
Mohamed, Mohamed, Zaman, Zayne, Wang, Xinyan, Zhao, Hua, Hall, Jonathan
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