Browse Topic: Power and Propulsion

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Experimental and Numerical Analysis of Direct Injection Process for Hydrogen-Fuelled Internal Combustion Engines2025-01-0307To 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
Technical Paper
A New Electrified Planetary Gear Set - The Cost- and Fuel-Efficient Alternative to Continuously Variable Transmissions2025-01-0309To 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
Technical Paper
Optimisation of Rotor Skewing of a Yokeless And Segmented Armature Axial Flux Machine2025-01-0311To be published on 07/02/2025
This paper presents an optimization of rotor skewing of an Axial Flux Machine (AFM) in a Yokeless And Segmented Armature (YASA) design in the torque-speed characteristics diagram. AFM have advantages regarding a compact design and high torque density compared to other variants of permanent magnet machines. The drive train Noise, Vibration and Harshness (NVH) performance is influenced by cogging torque, magnetic torque ripple and tooth forces. While the axial skewing of rotors in radial flux machines (RFM) has already been extensively studied to minimize these magnetic excitations, this represents a target value for optimizations in AFM. Optimizations are carried out and validated using 2D and 3D finite-element (FE) models. The 2D model combines multiple 2D slices but lacks accuracy because an insufficient inclusion of 3D effects. The 3D model allows to obtain a noticeable reduction by more than 30% of the dominant torque harmonic amplitudes over the whole torque-speed range in
Müller, Karsten, Maisch, Hannes, De Gersem, Herbert, Burkhardt, Yves
Technical Paper
Prediction of hazardous gaseous emissions from a gasoline engine during cold starts using machine learning methods2025-01-0321To 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.
Technical Paper
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
Technical Paper
Variable Valve Actuation and Split Injection to Enhance the Gas Exchange of a Passive Pre-chamber Igniter2025-01-0315To 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
Technical Paper
Impact of the distribution of charging and hydrogen refueling stations on their reachability for craft vehicles with a defined usage profile2025-01-0310To be published on 07/02/2025
This paper examines the impact of the distribution of charging and hydrogen refueling stations on their reachability for craft vehicles with a defined usage profile. A simulation-based methodology is presented for this purpose. The simulation models daily trips for craft vehicles, considering amongst others the company location, the client stops, the operating radius and the mean daily driving distance. Based on these inputs, the number of charging or refueling opportunities for typical daily trips of the craft vehicle is calculated. To investigate the impact of locations on the frequency of encountering energy provisions, simulations are conducted in three regions: Ulm (urban), Stuttgart (metropolitan), and Munderkingen (rural). Furthermore, the impact of different locations within the same infrastructural area is examined by assessing multiple company locations in Ulm. The findings indicate that the urban zone of Ulm is characterized by a highly dense electric fast charging
Heilmann, Oliver, Müller, Julian, Heinrich, Marco, Cortès, Sven, Schlick, Michael, Kulzer, André Casal
Technical Paper
Numerical analysis of direct-injection and combustion inside a H2 engine2025-01-0301To 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
Technical Paper
Application of Sustainable Aviation Fuels in Compression-Ignition Aviation Engines: In-Flight Investigations2025-01-0317To 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
Technical Paper
In Situ Observation of Different Soot Layers in a Model Filter Channel During Its Regeneration2025-01-0312To be published on 07/02/2025
To keep the air clean, wall-flow particulate filters are predominantly used in the exhaust gas after-treatment systems of combustion engines to remove reactive soot and inert ash particles. These filters consist of parallel porous channels with alternately closed ends, effectively separating particles by forming a layer on the filter surface. However, the particulate layer increases the pressure drop, requiring periodic regeneration. During regeneration, soot oxidation breaks up the particulate layer, while resuspension and transport of individual agglomerates may occur. These phenomena are influenced by gas temperature and velocity, as well as dispersity and the reactivity of the soot particles. Sustainable fuels can produce different types of soot with different reactivities and dispersities, therefore this study focuses on the influences of soot dispersity and reactivity by varying the reactive particle system. A model wall-flow filter channel is used for the investigation, enabling
Desens, Ole, Hagen, Fabian P., Meyer, Jörg, Dittler, Achim
Technical Paper
Requirements, Methods and Models for early Electrified Drive Concept Development2025-01-0304To be published on 07/02/2025
Computer-aided synthesis and development tools are essential for discovering and optimizing innovative concepts. Evaluating different concepts and making informed decisions relies heavily on accurate assessments of drive system properties. Estimating these properties in the early stages of development is challenging due to the depth of modelling required. In addition, defined requirements play a critical role in drive system sizing. This paper presents a tool chain for the synthesis of new electrified drive concepts, with emphasis on requirements definition and modelling. The requirements definition method combines market analysis with a generalized calculation and estimation approach, providing a novel perspective. In addition, we introduce mass and cost modelling capabilities integrated into the tool chain. The mass model achieves high accuracy, with deviations of only 1.6% at the vehicle level and 6.1% at the component level. Finally, the paper examines the mass and cost
Sturm, Axel, Henze, Roman
Technical Paper
Modular Thermal Management Framework for Electric Drive System Development2025-01-0262To 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
Technical Paper
Investigation on Thermal Management of Heavy-Duty Commercial FCEV with Focus on Vehicle System Efficiency2025-01-0265To 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
Technical Paper
Effect of Gasoline Component on Fuel Economy of WLTC Drive with EGR and Lean Combustion2025-01-0305To 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
Technical Paper
Optimization of Metallic Substrate by 1D simulations to fulfill High Power Cold Start Conditions2025-01-0308To 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
Technical Paper
Improving Gearbox Acoustics Through Elastomer-Based Bearing Damping2025-01-0323To 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
Technical Paper
Comprehensive optical and numerical investigation of hydrogen jet formation for a commercial gasoline hollow-cone injector2025-01-0313To 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
Technical Paper
Kinetic Energy Recovery: Assessment on the impact of Permanent Magnet Synchronous Motor and Battery Dynamic models2025-01-0303To 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
Technical Paper
Closed-loop real-time simulation of the thermal and electromagnetic behavior in electric drive trains: Optimizing model accuracy for virtual prototyping2025-01-0320To be published on 07/02/2025
This paper presents a coupled electromagnetic and thermal simulation of Permanently Excited Synchronous Machines (PMSM) in the context of virtual prototyping in a real-time Hardware-in-the-Loop (HiL) environment. Particularly in real-time simulations, thermal influences are often neglected due to the increased complexity of a coupled simulation. This results in inaccurate simulations and incomplete design optimizations. The objective of this contribution is to enable a precise and realistic real-time simulation that represents the electromagnetic as well as the thermal behavior. The electromagnetic simulation is executed used a Field-Programmable Gate Array (FPGA) and parameterized by Finite Element Analysis (FEA) results. The thermal model is based on a Lumped-Parameter-Thermal-Network (LPTN), which is based on physical laws, geometry parameters and material specifications. The simulation results are validated with testbench measurements to ensure the accuracy of the overall model. By
Jonczyk, Fabian, Kara, Onur, Bergheim, Yannick, Lee, Sung-Yong, Strop, Malte, Prochotta, Fabian, Andert, Jakob
Technical Paper
In-Depth Experimental Investigation into Performance and Emission Characteristics of a Diesel Light-Duty Engine Fuelled with Pure Hydrogen2025-01-0314To 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
Technical Paper
Upgradable Mechatronic Systems – Integration of Upgrade Planning and Design for Sustainable Vehicle Development2025-01-0290To be published on 07/02/2025
The automotive industry faces the challenge of developing vehicles that meet current customer requirements while being future-proof. Surveys show that customers fear financial risks associated with essential subsystems like batteries due to aging and performance degradation, which significantly affects the service life of vehicles. Therefore, the rapid technological progress in electrified powertrain systems requires innovative approaches for high adaptability to changing demands. This paper presents an approach combining foresight-based planning of system-level upgrades with product architecture design to create adaptable and sustainable vehicles through modularity. Potential battery and energy storage technologies are identified, their market introduction is forecasted, and they are analyzed technically-functional and geometrically to create flexible design spaces within the product architecture. This enables the future integration of new, more efficient, or higher-performance
Fehrenbacher, Rüdiger, Kuebler, Maximilian, Zeng, Yunying, Bause, Katharina, Albers, Albert, Nootny, Fabio, Kolbe, Lucia, Jung, Luca
Technical Paper
Minimum Sound Testing of Medium- and Heavy-Duty Electric Vehicles2025-01-5044To be published on 06/27/2025
The acoustic performance of seven vehicles was evaluated according to Canadian Motor Vehicle Safety Standard 141 (CMVSS 141), which governs minimum required sound levels for hybrid and electric vehicles with a gross vehicle weight rating (GVWR) of 4536 kg (10,000 lb) or less. To better understand the sound profiles of medium-duty electric vehicles (MDEVs) and heavy-duty electric vehicles (HDEVs), the sound emissions of two light-duty electric vehicles (LDEVs), one MDEV, three HDEVs, including an electric transit bus, and one heavy-duty internal combustion engine (HD ICE) vehicle were compared. The sound emissions of the MDEV and HDEVs were quieter than the HD ICE vehicle and comparable to that of the LDEVs equipped with auxiliary speakers. The MDEV with its auxiliary speaker turned off and all three HDEVs without auxiliary speakers met CMVSS 141 requirements in reverse gear and at speeds of 20 km/h and 30 km/h. The MDEV, though not subject to CMVSS 141, failed to meet the minimum sound
Sharma, Vinay, Larocque-Legros, Marc-André, Weston, Cole, Schulte, Andrew, Christenson, Martha, Rooney, Anne
Technical Paper
Experimental Analysis of Performance and Durability Using Ethanol 27% Fuel Blend in a Turbocharged Gasoline Direct Injection Engine2025-01-0245To be published on 06/16/2025
India aims to achieve 20% ethanol blending (E20) in petrol by 2025 under its National Biofuels Policy to reduce carbon emissions, enhance energy security, and support the agricultural economy. Building on this, E27 (27% ethanol in gasoline) is being evaluated as an advanced mid-level blend to further lower greenhouse gas emissions and reduce reliance on fossil fuels. This study investigates the performance, emissions, and combustion characteristics of a turbocharged gasoline direct injection (TGDI) engine using E27 fuel over 20,000 km in real-world driving conditions, as part of a broader research program accumulating over 100,000 km across multiple vehicle categories. Key findings indicate that E27 achieves an optimal balance of emissions reduction and performance, with NOx and THC emissions decreasing by 12% and 5%, respectively, compared to E10, while CO and CO₂ levels remained stable, reflecting ethanol’s oxygenation effect and lower carbon intensity. Power output and acceleration
D R, Vigneshwar, Bhakthavachalu, Vijayabaskar, Muralidharan, M.
Technical Paper
Three-Dimensional CFD Analysis of a Flat Engine Lubrication System2025-01-0215To be published on 06/16/2025
This study presents a comprehensive, transient, 3-D 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 gerotor pump, pressure regulation valve, bearings, piston cooling jets, oil cooler, oil filter, and other relevant components. The gerotor pump and gallery bearings were modeled using real 3-D geometries without any assumptions. Bearing deformation and orbiting due to force imbalance were prescribed in the simulations. The simulation was conducted at 5000 rpm of engine speed. The simulated flow pressure distributions closely matched experimental data.
Shiyi, Pan, Nan, Zhang, Jing, Liu, Mingliang, Liu, Wei, Wang
Technical Paper
Flame Developments of Pilot Diesel Ignited Hydrogen Jet in an Optical Dual Direct Injection Engine2025-01-0237To 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 35 MPa in addition to a centrally mounted eight-hole diesel injector providing the ignition source for the H2. Firstly, the diesel pilot flame was examined without H2 to establish the combustion characteristics of the pilot flame. The pilot fuel energy was reduced from 1200 J to 120 J until the minimum repeatable diesel flame was found, which showed a flame distribution that 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 minimum pilot fuel quantity of 120 J was then used to investigate the ignition process of hydrogen main fuel mixtures supplying 90% energy and only 10% energy
Heaton, Alastar, Chan, Qing Nian, Kook, Sanghoon
Technical Paper
Morphology Experiment of Icing Effect on Spray Propagation2025-01-0222To be published on 06/16/2025
The working conditions of combustion systems have been going extreme under the desire of human beings exploring the unknown. Cold environments can be a significant impact on the spraying of fuel not only by changing the fuel properties including viscosity and surface tension, but also by freezing the parts. In the present study, methanol spray from a commercial injector is studied via high-speed imaging, with the liquid fuel being frozen to sub-zero degrees at the injector tip. It is observed that water components from the environment will freeze at the injector tip, creating crystal structures on the surface. During the injection, the ice components will be flushed by the liquid, and the spray morphology of the starting cycle will be strongly altered, resulting in wider spray angles, much shorter penetrations, and particle structures can be observed in the downstream of the flow field. The results of the experiment provide a clear view and quantified evaluation of the freezing impact
Zeng, Tingxi, Wang, Shangning, Zhang, Yijia, Hung, David, Xu, Min
Technical Paper
“A Comparative Assessment of Port Fuel Injection and Direct Injection of Hydrogen in Internal Combustion Engines: Performance, Efficiency, and Emissions”2025-01-0239To be published on 06/16/2025
With the transition toward low-carbon fuel-based transportation systems, hydrogen is becoming increasingly promising as a sustainable internal combustion engine (ICE) fuel. There are two pathways for introducing hydrogen: Port Fuel Injection (PFI) and Direct Injection (DI) in an engine, which greatly affect performance, efficiency, and emissions. In the Port Fuel Injection (PFI), hydrogen is introduced into the intake manifold and mixed with air before reaching the combustion chamber. This approach is preferred due to its affordability, ease of use, and compatibility with current engine configurations. Because of PFI's more uniform air-fuel mixture, combustion is smoother, and NOx emissions are reduced. On the other hand, it raises the possibility of pre-ignition, particularly when engine loads are high, and a decrease in volumetric efficiency due to a reduction in the volume of intake air as hydrogen replaces it. Direct injection gives exact control over the timing and volume of fuel
Ahirwar, Sachin, Kumar, Naveen
Technical Paper
NVH Improvement of Transmission Electric Oil Pump with Uneven Pitch Control2025-01-0252To be published on 06/16/2025
This paper proposes an uneven pitch control for electric oil pumps. For the noise reduction of vane pumps, mechanical arrangements of uneven pitch vain angle are widely used. However, the tooth angle of gear-type pumps should be even mechanically. The proposed uneven pitch control provides similar effects of the mechanical uneven pitch arrangement by instantaneous motor torque controls of the electric oil pump which cannot have uneven pitch mechanically. The magnitude of motor torque for each pump tooth is determined by an uneven pitch formula which is widely used for mechanical vane pumps in previous study and patents. A formula for the shape of motor torque is proposed by analyzing pressure fluctuations of pump as a combination of trigonometric and exponential functions. The calibration factors for the magnitude and shape are adjusted by characteristics of pumps. The experimental results showed that noise reduction and dispersion effects of the proposed method.
Choi, Chinchul, Kim, Jongbeom
Technical Paper
Comparison of Spark and Turbulent Jet Ignition in a Fully Ammonia-Fueled Engine2025-01-0201To 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, elevated emissions of nitrogen oxides (NOx), and unburned 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 diesel engine platform 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
Technical Paper
Effects of Double Injection Strategy in a Diesel-Ammonia Dual-Fuel Engine2025-01-0206To 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. A diesel micro-pilot (MP) injection was used to ignite ammonia combustion, and diesel and ammonia were injected separately into the cylinder through dedicated injectors. The first MP injection timing was fixed at reference 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 the
Park, Chansoo, Jang, Ilpum, Park, Cheolwoong, Kim, Minki, Park, Gyeongtae
Technical Paper
Effect of Ignition Condition and Fuel Octane Number on Knock Intensity in a Small 2-Stroke Engine2025-01-0211To be published on 06/16/2025
Internal combustion engines (ICEs) remain widely used in automotive transportation for their high energy storage system efficiency and economic benefits. The 4-stroke engine has dominated all other forms to date, because the Otto cycle is relatively simple to understand. However, the significant benefits such as less pumping work and friction, lighter construction of 2-stroke engine, are attractive for applications that prioritize the simplicity and power density as well as meet the emission regulations. The disadvantages of the 2-stroke engine are mainly caused by the lack of sufficient scavenging process. Also, the overlap of the intake and exhaust phases results in charge short-circuiting, more fuel consumption and high unburned hydrocarbon emissions. For these reasons, it is difficult for 2-stroke engines to achieve stoichiometric combustion, making them incompatible with 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
Technical Paper
Residual Gas and Emission Characteristics in a Propane-Fueled Spark-Ignition Engine with Varying Combustion Durations2025-01-0202To 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
Technical Paper
Ammonia-Diesel Engines Segmented Modeling Approach and Simplified Combustion model Research2025-01-0232To 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, Yanzhao, Lyu, Xiaodong
Technical Paper
Combustion and Emission Characteristics of Marine Ammonia-Diesel Dual Fuel Engine with Micro-Pilot Injector Change2025-01-0235To be published on 06/16/2025
Recently, as regulations on greenhouse gas emissions have become stricter, driven by global warming, there is increasing interest in engines utilizing environmentally friendly fuels. In this context, ammonia is attracting attention as a potential alternative to fossil fuels in the future. However, due to its distinct fuel properties compared to conventional fuels, research is being conducted on utilizing diesel as an ignition source for ammonia. In this study, the effects of diesel injector fuel flow rate, and micro-pilot (MP) diesel injection timing on combustion and exhaust emission characteristics were analyzed in a single cylinder 12L marine ammonia-diesel dual-fuel engine. Two types of diesel micro-pilot injectors were tested. The first one was high flow rate micro-pilot injector (HMPI) and the second one was low flow rate micro-pilot injector (LMPI). HMPI injector had 66% more number of fuel injector nozzle hole and 250% larger fuel flow rate. Therefore, HMPI injector could
Jang, Ilpum, Park, Cheolwoong, Kim, Minki, Park, Chansoo, Kim, Yongrae, Park, Gyeongtae, Lee, Jeongwoo
Technical Paper
Design and Optimisation of a Passive Pre-Chamber Ignition System for a Heavy-Duty Hydrogen Engine at Lean Conditions2025-01-0229To 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 aspect that can potentially 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 inject the turbulent jet 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 specifically for Hydrogen combustion to
Keshtkar, Hossein, Feng, Yizhuo, Zhao, Hua, Wang, Xinyan
Technical Paper
Hydrogen Jet Characteristics of an Outward-Opening Injector Based on Schlieren Imaging2025-01-0228To 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 attention. 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 applications. 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 the 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
Technical Paper
Analysis of Combustion Characteristics of a Small 2-Stroke Opposed Piston Engine Using an Optically Accessible Engine and Numerical Analysis2025-01-0223To 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
Technical Paper
A Study on Improving the Methodology for Torque Modeling Using a Virtual Engine Model2025-01-0204To 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
Technical Paper
Sound Granular Synthesis Method for Sc-Fi Sound Quality of Electric Vehicles2025-01-0253To 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, based on the designed sci-fi target sound characteristics, a sound grain generation method using the adaptive principal frequency technique is proposed, and the overlap-and-add (OLA) method is employed to synthesize the sound grains. Then, to enhance the sound continuity and smoothness during the sound synthesis process, a method for optimizing a composite cosine window function using a
Liu, Dezhu, Liu, Zhien, Xie, Liping, Lu, Chihua
Technical Paper
Investigating Lubricants Base Oils Reactivity in Ammonia Engines via Accelerated Aging2025-01-0240To 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
Technical Paper
An Experimental Study on Aqueous Ammonia and Diesel Dual-Fuel Combustion with Ignition Improving Additives in a Compression Ignition Engine2025-01-0231To 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 has health risks 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 and, 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 co-combustion and pollutant emissions of burning such a fuel remain less understood. This study therefore explores the potential of using
Han, Yanlin, Hellier, Paul, Schonborn, Alessandro, Ladommatos, Nicos
Technical Paper
Numerical Simulation and Parametric Optimization of Engine/Powertrain Mounts: Identifying Key Design Variables to Reduce NVH Noise2025-01-0251To be published on 06/16/2025
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. 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. 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, making unintended contact with other
Ganesan, Karthikeyan, Seok, Sang Ho
Technical Paper
Effects of Injection and Intake Timing on Atomization and Combustion in a Hybrid Gasoline Direct Injection Optical Engine under the Low-Speed Low-Load Condition2025-01-0203To be published on 06/16/2025
With the growing trend of hybridization in modern engines, hybrid gasoline direct injection (GDI) engines are typically designed for high load at BMEP of 6 to 10 bar, low-to-mid speed of 2000 to 3000 rpm to achieve optimal fuel economy. However, these engines inevitably operate under low-speed, low-load conditions, such as during engine startup and low-speed cruising, where insufficient intake air often leads to poor air-fuel mixing and weak turbulence, resulting in suboptimal combustion. Adjusting intake and injection timing presents a simple and effective approach to optimizing the combustion process in hybrid GDI engines. In this study, an optical engine with a combustion system geometry identical to that of an advanced hybrid GDI engine was used. The engine featured a compression ratio of 15.0:1 and was equipped with a variable timing camshaft for intake timing control and an electronically controlled system for injection timing. High-speed color imaging, using transparent pistons
Cui, Mingli, Fu, Jinhong, Man, Xingjia, Nour, Mohamed, Zhang, Weixuan, Li, Xuesong, Xu, Min
Technical Paper
Development of the Central Coordinated Motion Control System for Pure Electric Vehicles2025-01-0188To be published on 06/16/2025
The article introduces the air springs, CDC, rear-wheel steering system, braking system, front-wheel steering system, and electric drive system in the vehicle’s central coordinated motion control system. It explores achieving more comfortable shock absorption by adjusting the CDC (Continuously Variable Damping system) damping and other means. By combining open-loop and closed-loop rear-wheel steering control, the turning radius in small-radius steering mode is reduced by up to 10%, enabling crab-walking, optimizing the moose test entering speed up to 90.9 kph, and improving vehicle behavior on split-friction surfaces. Through the cooperation of IBS (Intelligent Brake System) and VMC, an extremely comfortable braking process is achieved.
Zhou, Yuxing, Li, Wen
Technical Paper
Applied Full-Bridge Micro Strain Gauge to High Pressure Sensor for Gasoline Direct Injection/Hybrid System2025-01-0220To 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
Technical Paper
Research on Combustion Characteristics of Flash-Boiling Spray in Cylinders Based on Machine Learning Methods2025-01-0205To 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 flash-boiling 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
Technical Paper
Commercial Vehicle’s Exhaust Front Pipe Reliability Improvement through Virtual Simulation and Experimental Validation2025-01-0209To 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
Technical Paper
Higher Content n-Butanol Blending Ratios in Diesel Fuel Spray and Combustion Characteristics: Addressing Oxygenated Fuel Challenges with Spark-Assisted Combustion Strategies2025-01-0210To 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
Technical Paper
CFD Study of Lubrication Pump Starvation Due to Oil Pan Sloshing2025-01-0213To 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 a system of lubrication pumps, simulated using Simerics-MP+®. A series of numerical simulations are conducted at a given pump speed and extreme oil pan tilt angles or accelerations relevant to a high performance vehicle. Time-dependent oil distributions are visualized, and real-time oil flow rates are monitored at the pickup tubes to assess the impact of oil dynamics and pan position on pick-up tube 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
Nan, Zhang, Shiyi, Pan, Jing, Liu, Mingliang, Liu, Wei, Wang
Technical Paper
Influence of Fuel Surface Tension and Viscosity on Internal Flow Bubble Formation and Atomization in Flash Boiling Sprays2025-01-0221To be published on 06/16/2025
Flash boiling atomization is considered a promising atomization technique for combustion applications in automotive powertrains. It can potentially address the deteriorated atomization issue for alternative fuels (such as methanol) in internal combustion engines. However, it has been observed that flash boiling spray atomization for methanol fuels is not as effective as that for traditional alkane-based fuels. This work aims to explain such phenomena using transparent nozzles to reveal the impact of internal vaporization on external spray breakups. Three different working fluids, including methanol, ethanol, and pentane, are tested with elevated temperatures. The flow patterns and external liquid breakup are shown with the high-speed imaging technique. It is found that the internal phase change of the base working fluid is suppressed when ethanol or methanol is used instead of pentane. Consequently, the external liquid breakup is also hindered due to insufficient vapor phase inside the
Zhang, Yijia, Li, Yilong, Wang, Shangning, Zeng, Tingxi, Xu, Min, Hung, David, Li, Xuesong
Technical Paper
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