Browse Topic: Engines

Items (43,115)

Prediction of hazardous gaseous emissions from a gasoline engine during cold starts using machine learning methods

2025-01-0321To be published on 07/02/2025

Internal combustion engines generate higher exhaust emissions of hazardous gases during the initial minutes after engine start. Experimental data from a state-of-the-art turbo-charged 3-cylinder, 999 cc gasoline engine are used to predict cold start emissions using two Machine Learning (ML) models: a Multilayer Perceptron (MLP) which is a fully connected neural network and an Encoder-Decoder Recurrent Neural Network (ED-RNN). Engine parameters and various temperatures are used as input for the models and NOx (Nitrogen Oxides), CO (Carbon monoxide) and unburned hydrocarbon (UHC) emissions are predicted. The dataset includes time series recordings from the Worldwide harmonized Light-duty vehicles Test Cycle (WLTC) and four Real Diving Emissions (RDE) cycles at ambient and initial engine temperatures ranging from -20 °C to +23 °C. In total, 21 cases are considered, consisting of eight different ambient temperatures and five distinct driving cycles. Each case consists of a sequence of 2500

Mangipudi, Manoj, Denev, Jordan A., Bockhorn, Henning, Trimis, Dimosthenis, Koch, Thomas, Debus, Charlotte, Götz, Markus, Zirwes, Thorsten, Hagen, Fabian P., Tofighian, Hesam, Wagner, Uwe, Braun, Samuel, Lanzer, Theodor, Knapp, Sebastian M.

Variable Valve Actuation and Split Injection to Enhance the Gas Exchange of a Passive Pre-chamber Igniter

2025-01-0315To be published on 07/02/2025

Pre-chambers, in general, represent an established technology for combustion acceleration by increasing the available ignition energy. Realizing rapid fuel conversion facilitates mixture dilution extension with satisfying combustion stability. More importantly, knock-induced spark retarding can be circumvented, thus reducing emissions and increasing efficiency at high engine loads. Adapted valve actuation and split injections were investigated for this study to enhance the gas exchange of a passive pre-chamber igniter in a single-cylinder engine. The findings support the development of passive pre-chamber ignition systems operable over the whole engine map for passenger vehicles. There are two configurations of pre-chamber igniters: passive pre-chambers and scavenged pre-chambers. This study focuses on the passive design, incorporating an additional small volume around the spark plug into the cylinder head. Hot jets exit this volume after the ignition onset through several orifices

Fellner, Felix, Härtl, Martin, Jaensch, Malte

A New Electrified Planetary Gear Set - The Cost- and Fuel-Efficient Alternative to Continuously Variable Transmissions

2025-01-0309To be published on 07/02/2025

In order to mitigate the effects of climate change, the global transport sector, one of the largest emitters of CO2, needs to drastically reduce its emissions. Although hybridization and electrification are becoming increasingly popular as a solution for a variety of applications, their use in two- and three-wheelers, as well as in recreational and powersports vehicles, remains limited due to their high costs and complexity compared to conventional drivetrains with continuously variable transmissions (CVTs). Despite their affordability and simplicity, CVTs suffer from low mechanical efficiency, with transmission losses ranging from 20–50 %, highlighting a significant opportunity for improvement. In response to these limitations, this study presents the development and experimental evaluation of an electrified planetary gear set (ePGS) in a lightweight off-road vehicle. It is designed to overcome the efficiency limitations of CVTs while maintaining high driving comfort and low system

Jakoby, Moritz, Engels, Michael, Fahrbach, Timm, Andert, Jakob

Experimental and Numerical Analysis of Direct Injection Process for Hydrogen-Fuelled Internal Combustion Engines

2025-01-0307To be published on 07/02/2025

In the context of the clean transport sector, there has been growing interest in the use of hydrogen in internal combustion engines due to its potential to nearly eliminate all engine-out criteria pollutants, while maintaining high thermal efficiency through the use of a lean combustion process. Direct Injection (DI) is widely recognized as a method for enhancing thermal efficiency and minimizing the risk of abnormal combustion. However, a major challenge is the reduced time available for mixture homogenization, making injection timing a critical parameter to optimize. To address this, a comprehensive experimental campaign was conducted in a constant volume vessel to assess the performance of a hydrogen injector using the Schlieren technique. The jet behavior was analyzed by varying injector recess, injection pressure, and back pressure. Subsequently, the case study was replicated in a 3D Computational Fluid Dynamics (CFD) environment, addressing the complexities associated with

Pucillo, Francesco, Piano, Andrea, Millo, Federico, Giordana, Sergio, Rapetto, Nicola, Vargiu, Luca

Method for externally controlled availability of lubricating oil in internal combustion engines.

2025-01-0302To be published on 07/02/2025

Reduced emissions in internal combustion engines (ICE) are a key component in reaching green-house-gas and pollutive emissions regulations. With increased effort, clean and efficient burning combustion cycles are being developed. With the need of even more efficient engines the friction of ICE engines plays an increasing role in engine efficiency. Also, ingress of lubricating oil into the combustion chamber is a source of particle emissions. Increased optimization to reduce parasitic drag in the piston assembly such as reduced ring pre-tension ore thinner grade oils further increase oil ingress into the combustion chamber with the result of increased particle emissions. The transport mechanisms of oil ingress into the combustion chamber therefore the topic of current research. Specially developed research engines with a vertical optical window have big potentials to visualize phenomena of the oil behavior inside the piston assembly in internal combustion engines. Therefore, these

Stark, Michael, Fellner, Felix, Härtl, Martin, Jaensch, Malte

Improving Gearbox Acoustics Through Elastomer-Based Bearing Damping

2025-01-0323To be published on 07/02/2025

This study analyses the effect of external damping of roller bearings on the acoustic behaviour of gearboxes in electric powertrains. The increasing adoption of electric vehicles has increased the importance of mitigating gearbox noise, as the lack of masking noise from internal combustion engines and the higher operating speeds of electric motors exacerbate the acoustic challenges. Gearbox noise, which is primarily caused by tooth mesh excitation and its transmission through shafts and bearings, requires strategies to minimise its impact on vehicle comfort and performance. External damping is introduced via adapters integrated into the outer bearing ring, which are used to modify the vibrational behaviour of the bearing assembly and reduce both structure-borne and airborne noise emissions. A systematic approach using Design of Experiments (DoE) methodology is used to quantify the effects of this damping. This approach allows the analysis of critical parameters including material

von Schulz, Kai, Linde, Tilmann, Jäger, Steffen

In-Depth Experimental Investigation into Performance and Emission Characteristics of a Diesel Light-Duty Engine Fuelled with Pure Hydrogen

2025-01-0314To be published on 07/02/2025

Transitioning to zero-carbon fuels is pivotal for expediting the reduction of carbon emissions. Hydrogen demonstrates significant adaptability and emerges as a principal zero-carbon alternative fuel for carbon-based internal combustion engine (ICE) platforms. Implementing hydrogen in both spark ignition (SI) and compression ignition (CI) engines has proven to be both economically viable and timely; nevertheless, it presents several technical challenges that must be addressed. The study analyses the performance and emissions of a single-cylinder boat engine converted from diesel to 100% hydrogen. A port fuel injection (PFI) system was adopted to operate the engine with hydrogen by replacing the diesel injector with a spark plug engine without any modification to the cylinder head. The engine features an automated shutdown system to mitigate intake backfire risks associated with hydrogen PFI systems. A comprehensive engine characterization was conducted at a wide range of relative air-to

Mohamed, Mohamed, Zaman, Zayne, Lu, Enshen, Feng, Yizhuo, Wang, Xinyan, Zhao, Hua

Comprehensive optical and numerical investigation of hydrogen jet formation for a commercial gasoline hollow-cone injector

2025-01-0313To be published on 07/02/2025

Hydrogen produced from renewable sources offers the opportunity to reduce future emissions and enable CO2-neutral mobility by both adapting existing internal combustion engines (ICE) and developing new combustion engine systems. One challenge of hydrogen direct injection (DI) ICE is to optimize the mixture formation to ensure low engine out emissions as well as high efficiencies. In the study presented in this paper, a conventional piezo hollow-cone gasoline injector, commonly used in passenger car series, was adapted for high-pressure hydrogen direct injection applications. Therefore, optical measurements within a low pressure chamber (LPC) were conducted using a high-speed Schlieren imaging measurement technique to visualize the injection behavior and jet pattern at various injection conditions. The visualization of density gradients during the injection process showed a slightly decreased relative gaseous penetration length (GPL) of 4% for hydrogen in comparison to helium while the

Fleischmann, Maximilian, Mirsch, Niklas, Ghanoum, Mohamad, Morcinkowski, Bastian, Adomeit, Philipp, Pischinger, Stefan

Effect of Gasoline Component on Fuel Economy of WLTC Drive with EGR and Lean Combustion

2025-01-0305To be published on 07/02/2025

It is becoming increasingly clear that research into alternative fuels, including drop-in fuels, is essential for the continued survival of the internal combustion engine. In this study, the authors have evaluated olefinic and oxygenated fuels as drop-in fuels using a single-cylinder engine and considering fuel characteristic parameters. The authors have assessed thermal efficiency by adding the EGR or air from 0 to the maximum value that allows stable combustion. Next, we attempted to predict fuel efficiency for four types of passenger cars (Japanese small K-car N/A, K-car T/C, Series-HV, and Power-split-HV) by changing the fuels. We created a model in OpenModelica to estimate fuel efficiency during WLTC driving. The results indicated that fuel economy could potentially be improved by adding an olefin fuel that burns stably even with a large amount of EGR or air and an oxygen fuel whose octane number increases. It was observed that the fuel economy improvement rate was particularly

Moriyoshi, Yasuo, Xu, Fuguo, Wang, Zhiyuan, Tanaka, Kotaro, Kuboyama, Tatsuya

Optimization of Metallic Substrate by 1D simulations to fulfill High Power Cold Start Conditions

2025-01-0308To be published on 07/02/2025

The future of the internal combustion engine is strictly related to his capability to have Life Cycle Emission comparable to the pure Battery Electric Vehicles. To achieve this goal, it will be necessary not only to have carbon free fuels but also to increase the hybridization of the powertrain in order to have lower fuel consumption. On the other hand, it will be necessary to reduce to almost zero any further emissions of pollutants. For this reason, highly sophisticated exhaust aftertreatment must be developed. One particular use case is the so-called High-Power Cold Start. This can occur for the Plug-In Hybrid Electric Vehicles when the transition from pure electric drive to ICE assisted drive happens during high load request, for example an acceleration on the freeway ramp. This use case has been evaluated by CARB and in many other works. Nevertheless, in this particular paper, the Authors would like to investigate which Metallic Substrate Technology fits better during a HPCS. This

Montenegro, Gianluca, Onorati, Angelo, Marinoni, Andrea, Della Torre, Augusto, Pace, Lorenzo, Konieczny, Katrin, Laurell, Mats, Klövmark, Henrik

Numerical analysis of direct-injection and combustion inside a H2 engine

2025-01-0301To be published on 07/02/2025

The direct injection of hydrogen (H2) inside internal combustion engines (ICEs) is gaining large research interest over the port-fuel injection strategy, because of several advantages as higher volumetric efficiencies, increased power output and reduced risks of abnormal combustion. However, the required high pressure ratios across the injector nozzle produce moderate-to-high under-expanded jets, characterized by complex flow structures. This poses a challenge for the numerical modelling of the mixture preparation by means of 3D computational fluid dynamic (CFD) approaches. In this work, a validated 3D-CFD methodology has been employed to simulate the closed-valve cycle of a direct injection H2 engine equipped with a centrally mounted hollow-cone injector and a non-axisymmetric piston bowl. First, injection and mixture preparation have been studied considering an early injection at the beginning of the compression stroke, and a delayed injection in the second half of the compression

Capecci, Marcolucio, Sforza, Lorenzo, Lucchini, Tommaso, D'Errico, Gianluca, Pezza, Vincenzo, Tosi, Sergio

Modular Thermal Management Framework for Electric Drive System Development

2025-01-0262To be published on 07/02/2025

The automotive industry is undergoing a major shift from internal combustion engines (ICE) to hybrid (HEV) and battery-electric vehicles (BEV), which has led to significant advancements and increased complexity in drivetrain design and thermal management systems. This complexity reflects the growing need to optimize energy efficiency, extend vehicle range, and ensure system reliability in modern electric vehicles. At the Institute of Automotive Engineering, a specialized synthesis tool for drivetrain optimization is used to identify the best drivetrain configurations based on specific boundaries and requirements. Building up on this toolchain a modular and adaptable thermal management framework has been developed, addressing another critical aspect of vehicle and drive development: efficient thermal circuit layout and its impact on energy consumption and overall system reliability. The thermal framework emphasizes the dynamic interactions between key components, such as electric

Notz, Fabian, Sturm, Axel, Sander, Marcel, Kässens, Christoph, Henze, Roman

Investigation on Thermal Management of Heavy-Duty Commercial FCEV with Focus on Vehicle System Efficiency

2025-01-0265To be published on 07/02/2025

The primary approach to meet the objectives of the EU Heavy Duty CO2 Regulation involves decarbonizing the road transport sector by battery electric vehicles (BEV) or hydrogen-fueled vehicles. Even though the well-to-wheel efficiency of hydrogen-fueled powertrains like fuel cell electric vehicles (FCEV) and H2-internal combustion engines (H2-ICE) is much lower in comparison to BEV, they are better suited for on-road heavy-duty trucks, long haul transport missions and regions with scarce charging infrastructure. Hence, this paper focuses on heavy-duty FCEVs and their overall energetic efficiency enhancement by intelligently managing energy transfer across coolant circuit boundaries through waste heat recovery, while ensuring that all relevant components remain within required temperature boundaries under both cold and hot ambient conditions. Results were obtained using a 1D-model that comprises all thermal fluid circuits (refrigerant, coolant, air) created through GT-Suite software

Uhde, Sophia, Langhorst, Thorsten, Wuest, Marcel, Naber, Dirk

Kinetic Energy Recovery: Assessment on the impact of Permanent Magnet Synchronous Motor and Battery Dynamic models

2025-01-0303To be published on 07/02/2025

This paper examines the influence of a detailed dynamic model of a Surface Permanent Magnet Synchronous Motor (SPMSM) on the accurate evaluation of kinetic energy recovery during braking in a mild hybrid vehicle. The model, implemented in MATLAB Simulink, is based on the motor's DQ equivalent circuit, accounting for transient effects, inductance variability, and magnetic saturation. Also, a 2nd Order Thevenin Equivalent model of the battery is used in order to take into account the bus voltage variability. Simulations reveal that the dynamic model predicts significant variations in energy recovery potential, with differences of up to 25% compared to static models under specific braking conditions. These discrepancies are particularly pronounced during high-speed high-torque transitions, where transient electrical behaviors strongly influence energy recovery. The model’s accuracy enhances the reliability of energy simulations, especially in scenarios involving frequent or intense

Lombardi, Simone, Federici, Leonardo, Tribioli, Laura, Bella, Gino

Application of Sustainable Aviation Fuels in Compression-Ignition Aviation Engines: In-Flight Investigations

2025-01-0317To be published on 07/02/2025

To achieve a significant reduction in net CO₂ emissions in the aviation sector, sustainable aviation fuels (SAFs) are considered a key factor. Current research efforts are therefore focused on SAFs, which exhibit properties that differ from conventional kerosene, particularly in aspects critical to compression-ignition (CI) engines, such as cetane number, evaporation behavior or lubricity. These differences necessitate dedicated investigations to assess their suitability and performance in such engines. However, real operating conditions — such as intake air- and exhaust- pressure levels during flight — cannot be fully replicated on standard engine test benches. For this reason, real flight experiments were conducted to address these limitations. Notably, this work marks the first instance of in-flight testing of SAFs in CI aviation engines, constituting a significant milestone in this research area. In the course of these investigations, ASTM D7566 Annex A2-compliant HEFA

Kleissner, Florian, Reitmayr, Christian, Hofmann, Peter

Evaluation of Several Jet Fuels under Compression-ignition Operation on Thermal Efficiency, NOx, Particulate Matter, and Particle Size Distribution

2025-01-0244To be published on 06/16/2025

Alternative fuels such as Fischer-Tropsch Synthesized Paraffinic Kerosene (FT-SPK) and Catalytic Hydrothermal Conversion Jet (CHCJ) are among those important sustainable aviation fuels (SAFs) for future transportation. However, these alternative fuels often vary in their fuel characteristics, which depend on feedstock and fuel production processes. Therefore, a detailed analysis of combustion, emissions, and efficiency of these alternative fuels must be performed under controlled experiments to understand the impact of fuel properties and operating conditions. Using a single-cylinder research engine (SCRE), extensive operating conditions were performed to realize any difference in performance that can be fundamentally understood by fuel properties (e.g., cetane number, heat of combustion, and density) of these fuels in comparison with Jet-A. The experimental setup includes high-speed data acquisition for combustion analysis and gaseous and solid emissions benches for nitrogen oxides

Cung, Khanh, Miganakallu Narasimhamurthy, Niranjan, Khalek, Imad, Hansen, Greg

Optimization of the lubricating oil composition to reduce emissions from hydrogen engines

2025-01-0212To be published on 06/16/2025

The decarbonization of the transport sector has become a priority for governmental authorities and industrial stakeholders alike, driving regulatory measures and innovation in powertrain technologies. Among the innovative solutions, hydrogen combustion engines have gained significant attention due to their customization to diverse applications, including heavy-duty vehicles, passenger cars, generators, and even two- and three-wheelers. Hydrogen combustion, characterized by high ignitability, rapid flame speed, soot-free operation, and water as a combustion by-product, introduces distinct challenges for engine lubrication. These unique characteristics require the development and adaptation of lubricant formulations to ensure optimal engine performance and durability. Specifically, tailored lubricants play a vital role in addressing four key challenges: pre-ignition, particulate emissions, water contamination, and wear protection. This study investigates the impact of crucial formulation

Gohl, Marcus, Wulff, Robert, Scholl, Peter, Chapelot, Pierre, Günthner, Michael, Jung, Philipp Emanuel

Numerical Simulation and Parametric Optimization of Engine/Powertrain Mounts: Identifying Key Design Variables to Reduce NVH Noise

2025-01-0251To be published on 06/16/2025

Abstract: Introduction: Engine and powertrain mounts are vital for isolating vibrations and reducing the transmission of Noise, Vibration, and Harshness (NVH) from the engine to the vehicle structure. Despite technological advancements, addressing NVH issues related to tribological factors continues to pose significant challenges in automotive engineering. Aim: This study aims to systematically identify and optimize design parameters of engine/powertrain mounts to minimize NVH levels using CAE tools and parametric optimization techniques in Abaqus and Isight, respectively. Purpose: The purpose of this research is to investigate the correlation between various design parameters of powertrain mounts and their impact on NVH characteristics. Specific attention is focused on noises such as clunking, banging, or thumping that emerge from the engine bay under dynamic conditions like acceleration, braking, or turning. These sounds often occur as the engine moves excessively due to worn mounts

Ganesan, Karthikeyan, Seok, Sang Ho

Comparison of spark and turbulent jet ignition in a fully ammonia-fueled engine

2025-01-0201To be published on 06/16/2025

Ammonia (NH₃) is an emerging carbon-free fuel with the potential to decarbonize the energy sector. However, its widespread adoption is hindered by challenges like low flame speed, high ignition energy, and elevated emissions of nitrogen oxides (NOx) and unburnt NH₃. These limitations necessitate innovative combustion strategies for efficient and stable engine operation. This study investigates the potential of turbulent jet ignition (TJI) to overcome these challenges through the implementation of a pre-chamber, a small auxiliary chamber equipped with a spark plug to create hot, reactive jets that propagate into the main chamber, promoting rapid combustion from distributed ignition sites. In this work, TJI operation is compared to conventional spark ignition (SI) in a Cummins ISB6.7 engine retrofitted for 100% ammonia operation. Experiments were conducted at 1200 and 1800 RPM across varying loads (25%, 50%, 75%, and 100%) with equivalence ratio and spark timing sweeps. Combustion

Dhotre, Akash, Voris, Alex, Okey, Nathan, Kane, Seamus, Northrop, William

Residual Gas and Emission Characteristics in a Propane-Fueled Spark-Ignition Engine with Varying Combustion Durations

2025-01-0202To be published on 06/16/2025

This research investigates the impact of combustion duration on combustion characteristics, emissions, and residual gas in a propane-fueled spark ignition engine under varying engine speeds. Using a two-cylinder V-twin engine and AVL-Boost simulation, experiments were conducted at speeds ranging from 3000 to 8000 rpm with combustion durations between 40° and 80° crank angle. The study integrates simulation and experimental methods to address challenges in measuring residual gas and effective release energy (ERE) under different conditions. Results show that longer combustion durations generally lead to increased residual gas and BSFC, while also influencing peak fire temperature, effective release energy, and emission characteristics. At 3000 rpm, optimal conditions were observed with a peak BMEP of 11.11 bar, torque of 25.01 Nm, power output of 14.87 kW, and a minimum BSFC of 311.43 g/kWh. Longer combustion durations elevated the residual gas, reaching up to 0.946 at 8000 rpm, and

Quach, Nhu Y, Lim, Ocktaeck

numerical investigation into the combustion and emission characteristics of ammonia direct injection mechanism

2025-01-0241To be published on 06/16/2025

Ammonia is an attractive option because of its relatively low greenhouse gas (GHG) emissions, high energy density, competitive cost, and ubiquitous infrastructure for manufacturing, storage, and distribution. In this work, the optimum combustion characteristics are investigated to propose an efficient ammonia engine for future investigation. The effects of ammonia addition on diesel combustion characteristics were numerically investigated in a CI engine. The investigation was conducted by structured 3D CFD modeling to analyze the combustion characteristics. The validation of the boundary condition was compared to the designed experimental ammonia engine. The direct injection timing of 10o-50oBTDC and injection pressure 300-800 bar was proposed to identify the optimum autoignition characteristics. The equivalence ratios 1, 0.75, 0.5, and 0.25 were used in order to analyze the high cetane number characteristics and the air-fuel ratio.

Setiawan, Ardhika, Lim, Ocktaeck

Decarbonisation of GDI Engines Utilising On-board Hydrogen Production in an Improved Design Thermochemical Exhaust Assisted Fuel Reformer

2025-01-0186To be published on 06/16/2025

Engine intake charge enrichment with hydrogen (H2) is one way to enhance engine thermal efficiency and reduce pollutant emissions while replacing carbon-based fuel. Waste energy from hot exhaust gas can be thermochemically recovered as hydrogen in catalytic exhaust gas fuel reforming, which can then be used in combustion. This study focuses on tailoring the design of the fuel reformer, including the catalyst chemistry and coating on ceramic and metallic structures, to benefit the whole system’s fuel economy and reduce engine out emissions. The main reformer improvements focused on exhaust flow management and interaction with the engine's after-treatment system, while the final stage focused on the reformer's internal design structure. The new design iteration enabled hydrogen production improvements in the range of 78% to 86% in the critical exhaust gas temperature range of 410 oC to 520 oC with gas hourly space velocities (h-1) in highly demanding engine operating conditions ranging

Lee, Seung Woo, Wahbi, Ammar, Herreros, Jose, Zeraati Rezaei, Soheil, Tsolakis, Athanasios, Millington, Paul

Combustion and emission characteristics of marine Ammonia-Diesel dual fuel single-cylinder engine with MP injector change

2025-01-0235To be published on 06/16/2025

Recently, as regulations on greenhouse gas emissions due to global warming have tightened, there has been growing interest in engines that use environmentally friendly fuels. In this context, ammonia is gaining attention as a potential alternative to fossil fuels in the future. However, due to the unique fuel characteristics of ammonia compared to traditional fuels, research is being conducted on using diesel as an ammonia ignition source. In this study, combustion and exhaust characteristics were compared according to the characteristics of micro-pilot diesel injectors in the marine ammonia-diesel dual fuel single-cylinder engine. Various injectors with different hole numbers and sizes were examined (Injector A: more holes and larger size, Injector B: fewer holes and smaller size). To maintain a constant energy ratio between ammonia and diesel at a steady load, the injection duration was adjusted, and the MP injection timing varied in 5 CAD intervals to evaluate performance and

Jang, Ilpum, Park, Cheolwoong, Kim, Minki, Park, Chansoo, Kim, Yongrae, Park, Gyeongtae, Lee, Jeongwoo

Flame developments of pilot diesel ignited hydrogen jet in an optical dual direct injection engine

2025-01-0237To be published on 06/16/2025

This study aims to characterise the flame development for hydrogen-diesel dual direct injection (H2DDI) in an optically accessible heavy-duty engine through high-speed imaging of the natural combustion luminosity. A single hole, side mounted injector was used to inject H2 at 350 bar in addition to a centrally mounted eight-hole diesel injector providing the ignition source for the H2. The diesel pilot flame was examined without H2 to establish the combustion characteristics of the pilot flame. The pilot fuel energy was reduced from 1200J to 120J while examining the distribution of the pilot flame as the H2 energy fraction was increased. The flame distribution transitioned from an initial quasi-steady diesel flame at peak load (1200 J), to a piston bowl wall-centric flame distribution (840 J) and then to an injector centric flame (120 J). The pilot fuel quantity of 120 J was selected to investigate the ignition process of hydrogen main fuel mixtures supplying 90% energy (only 10% energy

Heaton, Alastar, Chan, Qing Nian, Kook, Sanghoon

Commercial Vehicle’s Exhaust Front Pipe Reliability Improvement through Virtual Simulation and Experimental Validation

2025-01-0209To be published on 06/16/2025

The exhaust front pipe is a critical structural component in commercial vehicles, ensuring the leak-proof flow of exhaust gases into the exhaust after-treatment system while withstanding engine and frame vibrations. To isolate these vibrations, the front pipe is equipped with a flex connector capable of enduring various displacements at frequencies between 8-25 Hz. The position of the flex connector relative to the engine crank axis significantly impacts its structural reliability over its service life. This paper compares the existing design, which features a horizontally positioned flex connector, with a modified design that positions the flex connector vertically and changes the material from SS-304 to SS-321. Finite element analysis was conducted using Nastran software. The fatigue life of the existing flex connector design is approximately 1015 cycles. In contrast, the improved design demonstrates a fatigue life of 1727 cycles, representing a 70% increase in durability compared to

Chandel, Kushal, Paroche, Sonu, Namdev, Akhilesh, Jain, Shailendra, Patil, Keyur

Thermal efficiency improvement and emission reduction of methanol spark ignition engine using lean-burn strategy

2025-01-0224To be published on 06/16/2025

Methanol is a promising fuel for achieving carbon neutrality in the transportation sector, particularly for internal combustion engine vehicles. With its high-Octane number, methanol enables higher thermal efficiency compared to gasoline engines. Additionally, its wide flammability range allows stable engine operation under lean burn conditions at low to mid-load levels. In this study, experiments were conducted on a single-cylinder engine to examine the combustion and emission characteristics under varying excess air ratios and injection timings. The results showed that the highest thermal efficiency was achieved at the highest excess air ratio, despite the lowest combustion efficiency and the longest burn duration. This outcome highlights that a larger air mass reduces heat loss and pumping loss. Furthermore, NOx emissions decreased due to the reduction in in-cylinder temperatures. However, HC emissions increased as a result of the decline in combustion efficiency

Lee, Seungwon, Kim, Hyunsoo, Hwang, Joonsik, Bae, Choongsik

Parametric Analysis of Injector Operational Parameters, Charge Dilution, and Intake Valve Opening on In-Cylinder Motion and Flame Development in an Automotive, Lean-Burn, Gasoline Engine with High-Tumble

2025-01-0198To be published on 06/16/2025

The effect of injection pressure, start of injection (SOI) timing, charge dilution, and valve timing on charge motion and early flame development was investigated for a pre-production automotive gasoline engine. Experiments were performed in a single-cycle optical engine designed to represent the high-tumble (Tumble ratio = 1.8), lean-burn engine. Time-resolved particle image velocimetry (PIV) was used to characterize velocity flow fields throughout the swept volume during the intake and compression strokes. Diffuse back illuminated imaging allowed for visualization and quantification of the injected liquid fuel spray and its interactions with the tumble vortex. Hydroxyl (OH*) chemiluminescence imaging was performed to image spark channel elongation and early flame kernel development. It was observed that an optimal injection timing of 320° before top dead center (bTDC) resulted in attenuation of the tumble motion and an associated reduction in compression flows that shifted the tumble

MacDonald, James, Ekoto, Isaac, Han, Donghee, Lee, Jonghyeok

An experimental and numerical study of ultra-lean combustion characteristics of methanol direct injection using various coil spark ignition strategies

2025-01-0200To be published on 06/16/2025

Methanol is significantly emerging as a promising alternative fuel in the pursuit of carbon neutrality. This study aims to analyze the combustion characteristics of methanol in a spark-ignition (SI) engine operating under high compression ratios and ultra-lean conditions through both experimental and simulation approaches. The objective is to derive optimized combustion efficiency by employing various ignition strategies based on discharge energy. To this end, experiments were conducted using a Rapid Compression Expansion Machine (RCEM) to replicate realistic engine environments. The effects of discharge energy and spark duration across different spark coil configurations were investigated through both experimental methods and computational fluid dynamics (CFD) simulations. The experimental results showed that the use of multiple spark coils achieved an energy release rate of approximately 239 mJ/s, more than twice that of the single-coil configuration. Simulation results were in good

Choi, Jeongyeon, Lim, Ocktaeck

Comparison of HRD and Petro Diesel in Industrial Engine Applications

2025-01-0243To be published on 06/16/2025

Renewable fuels are seen as a key enabler on the path to a lower carbon future. A low greenhouse gas fuel of particular interest is hydrotreated renewable diesel (HRD), also known as hydrotreated vegetable oil (HVO). HRD is of interest because it is a drop-in replacement to existing petroleum fuels used in diesel engines. An experimental investigation was undertaken to evaluate combustion characteristics of HRD versus a standard petroleum diesel. The work was carried out using a 2.5-liter fully instrumented single-cylinder research engine. This engine was chosen because it provides a very precise view of the difference in combustion and emissions of the fuels. Results represent the difference in combustion characteristics of the fuels, rather than potential differences in engine performance seen in a production engine, as each particular engine model will react a bit differently to the changes in combustion. The engine was operated according to three ISO 8178-4 test cycles: C1, D2, and

Bardell, Michael, Abi-Akar, Hind, Seiler, Patrick, Nash, Brady, McMahon, Donna, Ioannou, Marios

Noise Management in Electric Vehicle Compressors for Superior Cabin Comfort

2025-01-0191To be published on 06/16/2025

“This research addresses the issue of noise, vibration, and harshness (NVH) in electric buses, which can hinder their widespread adoption despite their environmental benefits. With the absence of traditional engines, NVH control in electric vehicles focuses on auxiliary components like the air compressor. In this study, the air compressor was identified as a major source of vibration, causing harsh contact between its oil sump and mounting bracket. Analyzing the vibrations revealed that the sump and bracket were not moving freely, increasing noise. Modifying the bracket design to allow more movement between the components successfully reduced both noise and vibration. The paper details the experimental process, findings, and structural damping methods to mitigate NVH in electric buses”.

Paroche, Sonu, Patel, Shubhanshi, Patidar, Ashok Kumar

Analysis of Diesel-Ethanol Blends: Impact on Spray Behavior and Combustion Properties under Various Injection Parameters in Compression Ignition Settings

2025-01-0208To be published on 06/16/2025

With rising fuel consumption across road transportation, there is growing interest in expanding the market share of renewable fuels, such as ethanol. Ethanol can be produced from raw materials from various starch-rich plants. In compression ignition engines, ethanol cannot be utilized on its own, largely due to its low cetane number. In this study, a constant volume combustion chamber (CVCC) is employed to investigate the effects of adding ethanol in diesel with different proportions (0%, 10%, 20%, 30% in volume) on the spray, combustion, and flame characteristics. Optical techniques, such as shadowgraph and flame self-illumination direct photography using high-speed imaging methods, were employed to reveal the spray and flame development process. This thesis examines the effects of varying fuel injection pressures (50, 80, and 110 MPa) and ambient pressures (1.5 and 3 MPa) on diesel-ethanol (DE) fuel blends. The study emphasizes the impact of DE blending ratios on the spray’s

Putra, I Komang Gede Tryas Agameru, Lim, Ocktaeck

Effects of Double Injection Strategy in a Diesel-Ammonia Dual-Fuel Engine

2025-01-0206To be published on 06/16/2025

This study investigates the application of a double injection strategy in a single-cylinder marine diesel-ammonia dual-fuel engine retrofitted for experimental analysis. Diesel micro-pilot (MP) injection was used to ignite ammonia combustion, with diesel and ammonia injected separately into the cylinder through dedicated injectors. The first MP injection timing was fixed at -20 CAD before ammonia injection timing, and both early and late double MP injection strategies were implemented to evaluate their effects on ammonia combustion, engine performance, and exhaust emissions. Under all conditions, the ammonia injection timing remained constant. Early double injection strategies, with the second MP injection occurring before the first, enhanced premixed diesel combustion by raising in-cylinder temperature and pressure. However, this early heat release was ineffective for ammonia evaporation and combustion due to poor timing alignment. In contrast, late double injection strategies, with

Park, Chansoo, Jang, Ilpum, Park, Cheolwoong, Kim, Minki, Park, Gyeongtae

Comparison of Methanol and Gasoline Fuel Spray Vaporization Using Direct-Injection Technology

2025-01-0225To be published on 06/16/2025

Considering the large opportunity to reduce net lifecycle carbon emissions through the use of renewable methanol, we address spray technologies needed to overcome the challenge of wall wetting and poor vaporization for methanol and the need for improved computational modeling of these processes. High-speed extinction imaging followed by computed tomography reconstruction is utilized to provide three-dimensional liquid volume fraction for reference fuel injectors, to be used for model validation activities. The first injector is the symmetric 8-hole Spray M injector for the Engine Combustion Network, and the second injector is an asymmetric 6-hole injector designed for lateral-cylinder mounting. The degree of plume interaction and vaporization are characterized at representative injection conditions, showing substantially higher concentrations of liquid for methanol than gasoline even with preheated fuel temperatures (90 degrees C). In light of higher injected mass requirements for

Wan, Kevin, Clemente Mallada, Rafael, Buen, Zachary, White, Logan, Oh, Heechang, Dhanji, Meghnaa, Pickett, Lyle

Start-Stop Gradeability simulation and methodology development for manual transmission vehicles

2025-01-0199To be published on 06/16/2025

Grade climbing capacity establishes a vehicle's distinguishing attribute of handling uneven roads and terrains thereby enhancing its overall performance capability. Vehicle availability and the testing procedure to determine gradeability requires a lot of time and effort. Aiming for the prediction of maximum start-stop gradeability of a vehicle and reducing the testing time and resources, a methodology is established representing the test procedure. A vehicle model is developed in GT Suite having dedicated modules of engine, clutch, transmission, vehicle and a driver. The vehicle is having weight of 2999 kg and a 1499 cc of engine with 80 hp power and 210 Nm torque. In simulation, the driver targeted the engine's launching speed profile, which progressively engaged the clutch to prevent engine stalling. The target is to ascend a specified distance in a predetermined amount of time without stalling the engine. Upon reaching the maximum grade the vehicle can climb, the engine will not be

Ramadandi, Padmavathi, Bose, Anshuman, Sirangu, Satish, Yeldo, Jabin, Edgar, Shawn, Salve, Siddhesh, Kaushik, Prince

Development of After-treatment Systems and Control Strategy for a Hybrid-dedicated Homogeneous Lean Burn Engine

2025-01-0217To be published on 06/16/2025

Lean-burn gasoline engines can improve fuel economy thanks to the higher specific heat ratio of the mixture and the reduced cooling loss during the combustion process. In addition, when combined with hybrid technology, the technology can achieve more synergies by overcoming obstacles such as limited operating conditions. However, the challenge of this technology is to reduce exhaust emissions to a level suggested by future stringent regulations. In lean-burn gasoline engines, nitric oxide (NOx) emissions are difficult to convert using conventional three-way catalysts (TWCs). Therefore, developing an effective NOx after-treatment system has been a key technology in the development of lean-burn engines. In addition, hydrocarbon (HC) emissions are also challenging because they increase under lean combustion conditions, while the lower exhaust temperature under lean conditions makes them hard to oxidize. Therefore, a catalyst technology capable of effectively converting HC, even at a low

Oh, Heechang, Lee, Jonghyeok, Sim, Kiseon, Lim, SeungSoo, Park, Jongil, Park, Minkyu, Kang, Hyunjin, Han, Donghee, Lee, Kwiyeon, Song, Jinwoo

Development of Simple Models for Performance Estimation of a Spark Ignition Engine Fueled with Ammonia and Hydrogen

2025-01-0238To be published on 06/16/2025

Achieving a carbon neutral society, eliminating greenhouse gas emissions is one of the most important issues. Ammonia is expected as a carbon free energy source. However, the laminar burning velocity of ammonia is much slower than hydrocarbons. Then, it is common to reform a portion of ammonia and use the ammonia/hydrogen mixture as a fuel. In this research, the operating characteristics of spark-ignition engine fueled with ammonia reformed gas is investigated and construct model estimating engine performance. A four-stroke single cylinder spark-ignition engine with a stroke volume of 212 cm3 is used. Total equivalence ratio is kept at unity and ammonia equivalence ratio is changed. Also, ammonia reformed gas is simulated as follows: ammonia and hydrogen are supplied from high pressure cylinders and injected by using automobile gaseous fuel injectors. Nitrogen is supplied from high pressure cylinder and supplied 1/3 of the molar ratio to hydrogen by a mass flow controller. The test

Ichikawa, Aya, Ogura, Yuto, Yanaoka, Kazuki, Gonzalez Palencia, Juan, Kambara, Shinji, Araki, Mikiya

A study on improving the methodology for Torque modeling using a virtual engine model

2025-01-0204To be published on 06/16/2025

This study aims to develop an engine torque prediction model using virtual engine simulation data. Accurate torque prediction is essential for minimizing shift shock and ensuring consistent driving performance, particularly in hybrid vehicles where smooth transitions between electric motors and internal combustion engines are necessary. The Engine Control Unit (ECU) uses a physics-based torque prediction model, requiring ignition timing swing data for precise calibration. The virtual engine model, based on 1D gas dynamics, was calibrated using real engine data obtained from a small number of main operating points. The simulation data obtained from the virtual engine model showed a good correlation with the experimental data. By combining large-scale simulation data with limited experimental data, we effectively calibrated the torque prediction model in ECU and confirmed that the calibration results met the development goals. This study demonstrates the potential for efficient engine

Hur, Donghan, Paeng, Jeonghwan, Kim, Kyusup, Chang, Jinseok, Park, Jongil

Effect of Ignition Condition and Fuel Octane Number on Knock Intensity in a Small 2-Stroke Engine

2025-01-0211To be published on 06/16/2025

The internal combustion engines are widely used on automotive transportation for its high energy storage system efficiency and economic benefits. The 4-stroke engine has dominated all other forms to date, because the Otto cycle is simpler to comprehend. However, the significant benefits such as, less pumping work and friction, lighter construction of 2-stroke engine, helped with applications which appreciate the simplicity and power density as well as meet the emission regulations. The disadvantages of the 2-stroke engine mainly caused by the lack of sufficient scavenging process, which limited its trapping efficiency. Also, the overlap of the intake and exhaust phases results in charge short-circuiting, more fuel consumption and high unburned hydrocarbon emissions. For the reason above, it is difficult for 2-stroke engines to realize stoichiometric combustion and unable to use three-way catalyst to control emissions. The residual exhaust gas in the cylinder makes the spark ignition

Liu, Jinru, Yamazaki, Yoshiaki, Otaki, Yusuke, Kato, Hayato, Yokota, Takumi, Iijima, Akira

Design and optimisation of pre-chamber ignition system for a heavy-duty hydrogen engine at lean conditions

2025-01-0229To be published on 06/16/2025

Strict regulations and legislation for carbon emissions and pollution from heavy-duty engines are pushing towards carbon-free fuels such as Hydrogen as a fuel for internal combustion engines. Moving towards this goal, the engine design needs to fully comply with Hydrogen’s unique characteristics to achieve optimum performance and efficiency. One of the aspects that has the potential to improve combustion efficiency and emissions is adopting the pre-chamber ignition strategy in large bore engines at lean conditions. The pre-chamber is a small cavity, usually 3-6% of the total engine volume, installed on the cylinder head, housing the initial combustion event, which would then be injected into the main chamber via nozzles placed at the bottom of the pre-chamber. This ignition strategy would provide multiple flame fronts into the main chamber, accelerating combustion speed and enhancing engine performance. However, the pre-chamber must be designed dedicatedly for Hydrogen combustion to

Keshtkar, Hossein, Feng, Yizhuo, Zhao, Hua, Wang, Xinyan

Hydrogen Jet Characteristics of an Outward-opening Injector based on Schlieren Imaging

2025-01-0228To be published on 06/16/2025

Hydrogen was considered as a promising carbon-free fuel for future society. The application of hydrogen in internal combustion engines has drawn more and more attentions. Jet performance of hydrogen injection plays a crucial role in characteristics of the hydrogen fuelled engines, in terms of mixture preparation, combustion and heat release in cylinder. In this research, an outward-opening injector was developed for hydrogen direct injection application. The jet performance was studied using high-speed schlieren imaging in a constant volume chamber and the effects of injection and ambient pressures on jet characteristics were investigated. The results show that, the hydrogen jet exhibits a conical structure in the near-field and overall presents a bell-shaped appearance under relatively low ambient pressure, which differs from irregular structure under relatively high ambient pressure. The pressure ratio, defined as the ratio of injection pressure to chamber pressure, significantly

Hu, Chaoqun, Hu, Longbiao, Chen, Haie, Li, Liguang, Wu, Zhijun, Deng, Jun

Investigating lubricants base oils reactivity in ammonia/hydrogen engines via accelerated aging

2025-01-0240To be published on 06/16/2025

As a carbon-free molecule, ammonia is more and more considered as a relevant fuel for long distance and off-road applications. However, this gas has different combustion characteristics compared to conventional fuels, challenging the suitability of lubricants to such engines. In this work, the evolution of lubricants under conditions mimicking ammonia combustion was assessed. Mineral and polyester lubricant base oils were exposed to oxygen, nitrogen oxides, and ammonia in a pressurized reactor under stirring. Oil aliquots were sampled at regular intervals, and characterized using Fourier Transform Infrared Spectroscopy (FTIR), viscosity and total oxygen and nitrogen contents measurements. Exposure to air containing nitrogen oxides resulted in quicker accumulation of oxidation products compared to neat air, for both the mineral and complex polyester base oil. Besides, exposure to gaseous ammonia in air resulted in a slower oxidation rate for both oils, compared to neat air. A global

Doncoeur, Carole, Giarracca, Lucia, Cologon, Perrine, Rousselle, Christine

Research on Combustion Characteristics of Flash-Boiling Spray in Cylinders Based on Machine Learning Methods

2025-01-0205To be published on 06/16/2025

With the increasing number of vehicles in operation, exhaust emissions from engines have exerted negative impacts on ecological environments, prompting researchers to actively pursue cleaner and more efficient in-cylinder combustion strategies. Flash-boiling spray technology, capable of generating superior fuel atomization under relatively low injection pressures, has emerged as a promising approach for achieving performance breakthroughs in gasoline direct injection (GDI) engines. While current research primarily focuses on morphological characterization and mechanistic analysis of flashboiling spray, there remains insufficient understanding of flame development characteristics under flash boiling spray conditions within engine cylinders. This study systematically investigates the combustion characteristics of TPRF and PRF fuels under both subcooled and flash-boiling spray conditions through the integration of image processing and machine learning methodologies. Experimental

Zhang, Weixuan, Shahbaz, Muhammad, Cui, Mingli, Li, Xuesong, Xu, Min

Ammonia-diesel Engines Segmented Modeling approach and Simplified Combustion model Research

2025-01-0232To be published on 06/16/2025

Ammonia-diesel dual-fuel engines can effectively reduce greenhouse gas (GHG) emissions. Aiming at the real-time control requirements of ammonia/diesel dual-fuel engines, this study proposes a segmented real-time modeling method and a heat release rate model simplification strategy by linearized heat release rate curves. First, the engine working cycle is divided into three parts: intake and exhaust stage, compression and expansion stage, and combustion process. Different simulation steps and modeling strategies are designed to optimize computational efficiency while maintaining the necessary level of accuracy at each stage. Secondly, based on the calibrated heat release rate (HRR) curves, feature points are extracted to construct a simplified linear heat release model. In the absence of calibration data, the characteristic points of the HRR curves are obtained through interpolation. Compared with the commonly used combustion model, the Wiebe model, the proposed simplified model can

Li, Guangyuan, Chen, Run, Wang, Xinran, Li, Tie, Zheng, Kexiong, Liu, Shaoling, Liu, Yanchao, Lyu, Xiaodong

Applied Full-Bridge Micro Strain Gauge to High Pressure Sensor for Gasoline Direct Injection/Hybrid System

2025-01-0220To be published on 06/16/2025

High Pressure Sensors (HPS) are essential for internal combustion engines and hybrid engine systems. High pressure sensor measures the pressure in the Delivery fuel rail Pipe Module (DPM) to allow the Engine Control Unit (ECU) to control the high pressure pump to generate the required fuel pressure. Most high pressure sensors measure the displacement of the metal-diaphragm according to pressure, and are mainly composed of Half-bridge type Micro Electro Mechanical System (MEMS) elements of the piezo-resistive method. This time, we would like to introduce a high pressure sensor that uses a Full-bridge type MEMS structure. This is cheaper than the existing one and can provide higher performance with reliability. However, there are disadvantages of the full-bridge type applied to high pressure sensors. Unlike the Half-bridge method that measures displacement over a wide area, it measures displacement over a narrow area, so it has the disadvantage of weak to external noise due to increased

Lim, SeungGu, Lee, DongYoung, Kim, JungTaek, Shin, MoonSung

Sound Granular Synthesis Method for Science Fiction Sound Quality of Electric Vehicles

2025-01-0253To be published on 06/16/2025

Since the powertrain systems of electric vehicles (EVs) lack the traditional engine sound, their NVH performance differs from that of conventional fuel-powered vehicles, making the use of active sound design (ASD) systems increasingly common to provide compensatory sound. With the increasing demand for ASD systems, sci-fi sounds are emerging as a design direction to enhance the acoustic feedback of powertrain systems and to elevate the futuristic and immersive driving experience of vehicles. A method for generating sci-fi soundscapes using a granular synthesis algorithm is proposed in this paper. First, a sci-fi sound is designed based on the characteristics of sci-fi sounds, which serves as the target sound for the synthesis algorithm. Then, it is proposed that sound grains are generated using the adaptive main frequency method, and granular synthesis is achieved through the overlap-and-add (OLA) method. In addition, a method for optimizing the composite cosine window function based

Liu, Dezhu, Liu, Zhien, Xie, Liping, Lu, Chihua

CFD Study of Lubrication Pump Starvation Due to Oil Pan Sloshing

2025-01-0213To be published on 06/16/2025

Dynamic vehicle operation, such as acceleration, deceleration, and tilting, can cause severe oil sloshing in the engine oil pan. This can lead to oil starvation at the pickup tube, compromising lubrication pump performance, and potentially damaging engine components. This study presents a Computational Fluid Dynamics (CFD) multiphase model of an engine oil pan and lubrication pump, simulated using Simerics-MP+. A series of numerical simulations were conducted at various pump speeds and extreme oil pan tilt angles. Time-dependent oil distributions were visualized, and real-time oil flow rates were monitored at the pickup tube to assess the impact of pump speed and pan position on oil starvation. This CFD model provides valuable insights into oil pan and pump behavior under extreme vehicle operation conditions, aiding in the design and optimization of lubrication systems to mitigate the risk of oil starvation and improve overall engine safety and performance.

Nan, Zhang, Shiyi, Pan, Jing, Liu, Mingliang, Liu, Wei, Wang

Three-Dimensional CFD Analysis of a Flat Engine Lubrication System

2025-01-0215To be published on 06/16/2025

This study presents a comprehensive, transient, 3D Computational Fluid Dynamics (CFD) model of a multi-cylinder flat engine's lubrication system, simulated using Simerics-MP+. Engine lubrication system is crucial for reducing friction, cooling, and cleaning engine components. Understanding its performance is essential for optimal engine operation. The model was applied to the lubrication system of a 4-cylinder, reciprocating internal combustion engine. The computational domain includes the positive displacement gear pump, pressure regulation valve, bearings, piston pins, piston cooling jets, oil cooler, oil filter, and other relevant components. Bearing deformation and orbiting due to force imbalance were prescribed in the simulations. A series of simulations were conducted under both fixed and time-dependent gear pump rotation speeds. For fixed speeds, the simulated flow pressure distributions closely matched experimental data. For time-dependent speeds, the predicted pressure buildup

Shiyi, Pan, Nan, Zhang, Jing, Liu, Mingliang, Liu, Wei, Wang

Higher Content n-Butanol Blending Ratios in Diesel Fuel Spray and Combustion Characteristics: Addressing Oxygenated Fuel Challenges with Spark-Assisted Combustion Strategies

2025-01-0210To be published on 06/16/2025

This study investigates the effects of oxygenated fuels, specifically long-chain alcohols, impact fuel atomization and combustion behavior in CI engines. The objective is to examine how higher n-butanol blending ratios in diesel fuel influence spray dynamics and combustion performance under varying engine conditions using an advanced combustion strategy. Experiments were conducted using a constant volume chamber (CVC) and a rapid compression-expansion machine (RCEM), both designed to replicate CI engine conditions. N-butanol was blended with diesel at ratios ranging from 70% to 90% with 10% increments, and key parameters such as spray formation, cone angle, penetration length, in-cylinder pressure, combustion performance, and efficiency were analyzed. The study also evaluated the effects of varying injection pressures on spray behavior. The results demonstrate that increasing n-butanol content significantly alters spray and combustion characteristics. Higher n-butanol proportions lead

Warsita, I Wayan, Lim, Ocktaeck

An Experimental Study on Aqueous Ammonia and Diesel Dual-Fuel Combustion with Ignition Improving Additives in a Compression Ignition Engine

2025-01-0231To be published on 06/16/2025

Ammonia is a potential vector of renewably produced hydrogen for combustion systems and decarbonisation of transport. However, anhydrous ammonia remains dangerous and difficult to handle due to its volatility and toxicity. Therefore, a water-based solution of ammonium hydroxide (NH4OH) was proposed to investigate the potential use as a fuel in a compression-ignition engine. Ammonium hydroxide, also referred to as aqueous ammonia, is liquid phase under atmospheric conditions; therefore, the storage of such a fuel does not require high pressure. Previous work has established that ammonium hydroxide solution could contribute to energy release during co-combustion with fossil diesel. However, the presence of water reduced combustion stability and limited the extent to which aqueous ammonia could displace diesel. In addition, the characteristics of pollutant emissions of burning such a fuel remained less understood. This study therefore explores the potential of ignition improving additives

Han, Yanlin, Hellier, Paul, Schonborn, Alessandro, Ladommatos, Nicos

Analysis of Combustion Characteristics of a Small 2-Stroke Opposed Piston Engine Using an Optically Accessible Engine and Numerical Analysis

2025-01-0223To be published on 06/16/2025

As global warming becomes more serious, decarbonization of internal combustion engines, which emit a large amount of carbon dioxide, is being promoted. It is predicted that many vehicles will still be equipped with engines in 2035, and a variety of powertrains will be required in the future. Therefore, we focused on the opposed-piston engine as an internal combustion engine specialized for power generation applications. The opposed-piston engine is characterized by its 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 reciprocating inertial forces of the left and right pistons. We believe that the engine for power generation can achieve the required high efficiency operation and vibration reduction. Therefore, in this study, combustion analysis of a two-stroke opposed-piston engine with features of low vibration, high efficiency, and high output

Yamazaki, Yoshiaki, Watanabe, Sou, Okawara, Ikumi, Otaki, Yusuke, Liu, Jinru, Iijima, Akira

Items per page:

1 – 50 of 43115