Browse Topic: Engine components

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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
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
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
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
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
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
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
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
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, 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
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, mid-to-high-speed operation to achieve optimal fuel economy. However, these engines inevitably operate under low-speed, low-load conditions 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 is used. The engine features a compression ratio of 15.0:1 and is 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 and cylinder liners, captures the in-cylinder spray development and combustion processes
Cui, Mingli, Fu, Jinhong, Man, Xingjia, Nour, Mohamed, Zhang, Weixuan, Li, Xuesong, Xu, Min
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 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
Technical Paper
Analysis of Diesel-Ethanol Blends: Impact on Spray Behavior and Combustion Properties under Various Injection Parameters in Compression Ignition Settings2025-01-0208To 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
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 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
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 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
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
A Comparative Assessment of Port Fuel Injection and Direct Injection of Hydrogen in Internal Combustion Engines: Performance, Efficiency, and Emissions2025-01-0239To be published on 06/16/2025
With the transition toward low-carbon fuels-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 affects 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
Ahirwar, Sachin, Kumar, Naveen
Technical Paper
Development of Combustion System for a Hybrid-dedicated Homogeneous Lean Burn Engine2025-01-0216To be published on 06/16/2025
This study explores methods to extend the lean combustion limit, improve efficiency, and reduce engine-out emissions in a hybrid-dedicated homogeneous lean combustion engine. Under lean combustion conditions, slow laminar flame speed restricts flame kernel growth, leading to instability and limiting the lean combustion threshold. To address this challenge, a combustion system was developed that leverages the engine’s internal flow to enlarge the spark channel at the spark gap and promote the formation of a larger-scale flame kernel. The combustion chamber was optimized by redesigning the intake port geometry and piston bowl to generate a high tumble flow. This new design significantly increased airflow around the spark plug gap, accelerating the initial combustion process and effectively expanding the lean combustion limit. Additionally, multiple ignition was implemented to prevent spark channel shortening caused by increased electrical resistance, further enhancing combustion
Oh, Heechang, Lee, Jonghyeok, Sim, Kiseon, Park, Jongil, Kim, Taekyun, Kang, Hyunjin, Hong, Seungwoo, Han, Donghee, Kim, Dokyun
Technical Paper
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-Tumble2025-01-0198To 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
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
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
Technical Paper
Design and optimisation of 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 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
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, 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
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
Evaluating Powertrain Mount Decoupling: Insights from Simulation, Experimental Results, and Analytical Calculations2025-01-0022To be published on 05/05/2025
This study presents a thorough examination of engine mount decoupling by integrating virtual simulations, physical testing, and analytical calculations. Engine mounts are crucial for isolating vibrations and enhancing vehicle comfort and performance, making their dynamic behavior vital for effective design. In our approach, we employ multi-body dynamics (MBD) simulations to model the interactions within engine mounts. By adjusting the bush stiffness parameters in the MBD framework, we can predict decoupling frequencies and analyze kinetic energy distribution. The bush stiffness values used in simulations are then applied in physical testing, ensuring consistency in the results for decoupling frequencies and kinetic energy distribution. This alignment between virtual and empirical data significantly enhances the reliability of our findings. Moreover, we conduct analytical calculations that correspond with the results from both the simulations and physical tests. This comprehensive
Shende, Kalyani, Shingavi, Shreyas, Rane, Vishesh, Hingade, Nikhil
Technical Paper
Indirect Blocked Force Measurement of a Hydraulic Power Pack for Structural Vibration Transmission into an Airframe2025-01-0052To be published on 05/05/2025
Centralization of electrically driven hydraulic power packs into the body of aircraft have increased the attention on the noise and vibration characteristics of the system. A hydraulic power pack consists of a pump coupled to an electrical motor, accumulator, reservoir, and associated filter manifolds. In previous studies, the characteristics of the radiated acoustic noise and fluid borne noise were studied. In this paper, we focus on the structure borne forces generated by the hydraulic pump characterized through blocked force measurements. The blocked force of the pump was determined experimentally using an indirect measurement method. The indirect method required operation with part under test fixed to an instrumented receiver structure. Measured operational accelerations on the receiver plate were used in conjunction with transfer function measurements to predict the blocked forces. Blocked forces were validated by comparing directly measured accelerations to predicted
Smither, Matthew, Tuyls, Zachary, Patel, Pratik, Yan, Xin, Herrin, David
Technical Paper
Optimization of HEV Vehicle’s Engine Modulated Noise2025-01-0084To be published on 05/05/2025
One 1.5L Miller-cycle turbocharged four cylinder gasoline hybrid engine is installed on a certain hybrid vehicle. When accelerating at low to medium speeds with a small throttle, there is a "da da" knocking noise inside the car, which seriously affects the overall sound quality of the vehicle. By analyzing the vibration and noise data of the engine, it was found that the frequency of the abnormal knocking sound is 200-1000Hz, which presents a half order characteristic in the time domain, that is, one knocking occurs when the engine crankshaft rotates twice. Through Hilbert demodulation analysis of the vibration data in the problem frequency range, it was found that the knocking noise was modulated in the frequency domain, with a modulation frequency of half of the crankshaft rotation frequency. By building a fully flexible multi-body dynamic model of a hybrid powertrain and inputting the engine's cylinder pressure excitation, the combustion excitation is coupled with mechanical
Dan, Kong
Technical Paper
Hybrid RLDA methodology for passenger car engine mount applications2025-01-0095To be published on 05/05/2025
In the development of engine mounting systems for passenger cars, accurately capturing dynamic loads during real-world driving conditions is crucial for optimizing performance, durability, and NVH (Noise, Vibration, and Harshness) characteristics. This paper introduces an innovative approach that integrates load cell and strain gauge technologies for Road Load Data (RLD) acquisition, specifically designed for engine mounting applications. By combining load cells and strain gauges, this method offers a comprehensive solution for measuring both direct forces and the resulting strains on engine mounts, providing a more detailed understanding of the load profiles. Load cells capture the overall forces exerted on the engine mounts, while strategically placed strain gauges measure local deformations and stress distributions within the mounts. This dual-method approach enables precise correlation of force and strain data, enhancing the accuracy of load calculations under various driving
Hazra, Sandip, Khan, Arkadip Amitava, Mohare, Gourishkumar
Technical Paper
Noise analysis and optimization of thermal management integrated module2025-01-0081To be published on 05/05/2025
Thermal Management Integration Module (TMIM), which comprises components such as water pumps, runner boards, brackets, sensors, etc., is a multifunctional integrated component for electric vehicles. However, the water pump generates an excitation over a wide range of frequencies due to a wide range of speed variations. This excitation causes the TMIM to vibrate and generate noise. In this study, a TMIM that generates noise is studied and analyzed. Using the TMIM of an electric vehicle as a case study, a full-vehicle experimental test was conducted, revealing that the noise originates from the integration module. The finite element method is used to analyze the cause of noise generation. Given the characteristics of the TMIM, which comprise many components, high integration, and a complex structure, this paper simplifies the bracket, heat exchanger, sensor, and other components using the centralized mass point method. The modal state of the TMIM is obtained by impact hammer testing the
Xu, Shenao
Technical Paper
Designing Rubber Flaps for Resonance Management: High-Frequency Tuning in Electric Vehicles Using AI/ML Approaches2025-01-0125To be published on 05/05/2025
High-frequency whine noise in electric vehicles (EVs) poses a significant challenge, affecting customer perception and the overall vehicle experience. One primary source of this undesirable noise is the interaction between motor pole resonance and the resonance of the engine mount rubber. This paper presents an innovative method for predicting and tuning the frequency response of engine mounts by precisely adjusting the dimensions of rubber flaps, specifically their length and width. The proposed solution employs a dual approach: fine-tuning rubber flap dimensions and utilizing machine learning (ML) techniques. An ML model, trained on historical data, predicts how varying flap dimensions impact frequency response, providing a data-driven foundation for optimization. This prediction capability is enhanced by a Python program that automates the optimization process using a linear combination formula, efficiently addressing resonance issues. By integrating ML insights with the linear
Hazra, Sandip, Khan, Arkadip
Technical Paper
Crash Performance Improvement: The Impact of Engine Mount Crash Plates on Achieving a 5-Star Safety Rating2025-01-0085To be published on 05/05/2025
Electric vehicles (EVs) differ from internal combustion engine (ICE) vehicles in that they lack a conventional engine and feature an electric drive unit, leading to distinct dynamic behaviours in the powertrain. Additionally, the arrangement of auxiliary components in EVs often differs from that in traditional ICE vehicles, which can sometimes significantly impact safety ratings. This paper examines a case study of a critical failure during a crash test, where displacement of an engine mount arm caused substantial structural intrusion and reduced the vehicle's safety rating. To address this issue and enhance crashworthiness, a "crash plate" was designed and integrated into the mount system. This solution effectively constrained the mount arm's movement during impact, preventing the intrusion observed in previous tests. The paper provides a detailed analysis of the crash plate's dimensions and its relationship to the engine mount, demonstrating its potential for broader application in
Hazra, Sandip, Khan, Arkadip, Mohare, Gourishkumar
Technical Paper
Simulation of Pass-by Fan Noise Emissions and Advancing Test Regulations for Heavy-Duty Electric Vehicles2025-01-0086To be published on 05/05/2025
The rapid adoption of electric vehicles (EVs) necessitates updates to the automotive testing standards, particularly for noise emission. This paper examines the vehicle-level noise emission testing of a Nikola Class 8 hydrogen fuel cell electric semi-truck and the component-level noise emission testing needed to create a predictive simulation model using Wave6 software. The physical, component-level noise emission testing focused on individual cooling fans in a semi-anechoic chamber to assess their isolated noise contributions. With this data, an initial model was developed using spatial gradient statistical energy analysis, which successfully predicted pass-by noise levels based on varying fan locations and speeds. Real-world pass-by testing confirmed the model's accuracy across different cooling fan speeds. By leveraging advanced simulation techniques, engineers aim to enhance the accuracy and reliability of pass-by noise predictions through cost-effective studies of architectural
Passador, Stephen, Woo, Sangbeom, Liu, Ting-Wei, De La Vega Alonso, Gerardo, Kim, James
Technical Paper
Drilling Methods for Controlling Exit Burr Height in CRES Material Stacks2025-01-0169To be published on 05/02/2025
The Electroimpact Automatic Fan Cowl Riveter uses two novel drill processes to control exit burr height and achieve the required hole quality in CRES (Corrosion-Resistant Steel, also called stainless steel) material stacks. Both processes use piloted cutters on the OML side, and two different tools are used in a backside spindle on the IML side of the component. The first process uses a shallow-angle shave tool in the IML spindle to directly control the exit burr height after it is produced by the OML spindle and is called the “burr shave” technique. The second process uses a countersink tool in the IML spindle and produces an “intermediate countersink” after the pilot hole is drilled by the OML spindle, but before the final hole diameter is drilled. These drill processes were able to achieve the required hole quality in a challenging CRES material stack, which allows the machine to be qualified for one-up assembly of the component.
Schultz, Rich, Peterman, Randy, Luker, Zachary, Murakonda, Sai Krishna
Technical Paper
Influence of Coolant Properties on Battery Thermal Management in Electric Buses during Cold Starts02-18-03-001304/25/2025
Improving electric vehicles’ overall thermal management strategy can directly or indirectly improve battery efficiency and vehicle range [1]. In this study, the effect of the coolant type used in BTMS (battery thermal management system) units used for heating batteries in cold weather conditions was investigated in electric buses. In this investigation, tests were performed with two types of antifreeze, which have different characteristics. The study evaluated the impact of coolant flow, BTMS circulation pump performance, and battery heating using these two types of antifreeze in the BTMS coolant line. In addition to carrying out tests, 1D computational fluid dynamics models’ simulations were carried out for both types of antifreeze, and the results were validated with experimental findings. In this study, a 12-m EV Citivolt vehicle of Anadolu Isuzu was used for tests. As a result, it was observed that differences in the properties of the antifreeze that is used in BTMS coolant line
Çetir, Özgür, Birgül, Çağrı Emre
Journal Article
Aerated Oil in the Rotating Channel03-18-03-001804/24/2025
In this article we examine the behavior of oil in the lubrication channel between the main bearing and the connecting rod bearing in the crankshaft of an internal combustion engine. The requirement for high service life and proper operation of these bearings, while minimizing input power of the lubrication system, lead to the need to understand the function of these structural parts in detail. To simulate and visualize this process, an experimental device was created. The device allows the experimenters to change individual parameters such as rotation speed, oil pressure, oil temperature, and aeration, while simultaneously visualizing the process with the help of a special rotating camera. These parameters are then obtained by image processing. In this way, the following influences are investigated here: at oil temperatures of 30, 50, and 80°C, relative oil pressures of 1, 2, 3, and 4 bar, at undissolved air in the oil of 5 and 10 vol% and crankshaft station speeds from 0 to 6000 1/min
Rychtar, Vaclav
Journal Article
Virtual Encoder for Achieving Crank Angle Resolution Measurements of In-Cylinder Pressure in Small Engines by using Time Based Data Acquisition2024-32-010504/18/2025
Small size engines feature several peculiarities that render them a challenge with respect to implementing measurements required for characterizing specific phenomena such as combustion evolution. Measuring in-cylinder pressure is well established as standard procedure for determining combustion characteristics, but in the case of small size units actually applying it can require alternative approaches. Fitting a crank angle encoder may be extremely difficult, as a consequence of the actual size of the power unit. Cost is another essential driver for small engine development that also influences how measurements are implemented. Within this context, the present work describes the development and implementation of a method that employs an algorithm that practically generates a ‘virtual’ encoder. Only a basic phasing signal is required, such as an inductive crankshaft position sensor output or that of an ignition pulser. The software was developed on an experimental engine with a crank
Irimescu, Adrian, Cecere, Giovanni, Merola, Simona Silvia, Vaglieco, Bianca Maria
Technical Paper
Prediction of Pre-Ignition Borderline on Supercharged SI Engine by Livengood-Wu Integral2024-32-000804/18/2025
The LSPI (Low Speed Pre-Ignition) is one of the consecutive abnormal combustion cycles of supercharged SI engine with direct injection fuel supply system [1]. The LSPI occurs when the engine is running at low speed and high load condition. It is important for the SI engine to control essentially with alternative fuel, e-fuel and hydrogen in the future. It is considered that the LSPI would be caused by the autoignition of the deposit, the lubricating oil from ring crevice, the lubricating oil from piston crown and so on [2, 3, 4, 5]. Among of these causes, this research focuses on the scattering lubricating oil from piston crown. The previous our research has reported on the two points. One is about the frequency and quantity of the lubricating oil scattering from piston crown [6]. Another is about the frequency of abnormal combustion by the engine test [7]. As the result, it has been cleared that the frequency of abnormal combustion is 1/10 of scattering frequency of the lubricating
Omori, Takaya, Tanaka, Junya
Technical Paper
Experimental Investigations of a Hydrogen Fueled Natural Gas Engine and Ion Current Measurement for Combustion Diagnostics in Pure Hydrogen Operationwith Water Injection2024-32-006504/18/2025
In the ongoing effort to decarbonize energy supply, a notable shift involves the conversion or retrofitting of combined heat and power plants to operate on hydrogen as an alternative to natural gas. In this transformative landscape, extensive research is underway to develop and explore innovative combustion processes for hydrogen-fueled engines, aiming to comprehend and optimize combustion processes concerning both engine performance and emissions. Among the various methods available for monitoring the combustion process and engine control, ion current sensing presents itself as a viable option. A unique feature of this research lies in utilizing the engine's spark plug itself as an electrical sensor, measuring the ion current generated during the flame development and combustion processes. Given the limited research on ion current sensing for hydrogen combustion processes, a series of experiments were conducted and presented in this work. These experiments involved sweeps of water-to
Salim, Naqib, Beltaifa, Youssef, Kettner, Maurice, Loose, Oliver, Weißgerber, Tycho
Technical Paper
A Concept for Functional Modelling of an E-Bike Powertrain2024-32-001704/18/2025
The increasing popularity of e-bikes, especially pedelecs, has led to a growing interest in consideration of e-bike cycling. To achieve a deeper understanding on the process of e-bike cycling and in particular the effects on the rider it can be instrumental to use simulation methods. In this context, the e-bike drive system and its function are of central importance for e-bikes. Therefore, this work proposes a functional modeling of the powertrain of an e-bike with a mid-drive motor, considering legal constraints and support functionalities. The model incorporates the mechanical transmission between pedals, motor, and crank shaft, allowing for a detailed analysis of the e-bike’s performance. Additionally, the support mechanism is depicted, where an electric motor amplifies the rider’s pedaling torque. The electrical behavior of the motor, energy consumption, and battery state of charge are also integrated into the model. This comprehensive approach aims to provide a generic
Rauch, Yannick, Kettner, Maurice, Kriesten, Reiner
Technical Paper
Dynamic Analysis of Intake and Exhaust Valve Motion in a High-Performance four Stroke Engine. Part 2 - Development of a Numerical Model for the Simulation of the Valvetrain2024-32-008404/18/2025
The intake and exhaust valve motion have, as known, a pivotal role in determining engine operation and performances. When dealing with high specific power engines, especially at high rpm, the dynamic behavior of the valve can differ from the kinematic one defined during the design phase. This is related to the high acceleration and forces to which the valve and the other components of the valvetrain system are subjected. In particular, the valve can detach from the cam profile at the end of the opening stroke, and it can show a bouncing behavior during the closing stroke. In addition, all the elements of the valvetrain system are not infinitely rigid and aspects such as the timing chain elongation, the camshaft torsion and the valve stem compression can determine a change in phase with respect to the kinematic one. Since the high complexity level of valvetrains, advanced numerical simulations are mandatory to deeply analyze the behavior of the whole mechanism and each subsystem. The
Tarchiani, Marco, Romani, Luca, Raspanti, Sandro, Bosi, Lorenzo, Ferrara, Giovanni, Trassi, Paolo, Fiaschi, Jacopo
Technical Paper
A Study on Optimal Combinations of Winding and Cooling Methods for Downsizing Power Units in Motorcycles2024-32-000704/18/2025
In commercially available electric motorcycles, there is a notable shift in the cooling method, moving from air cooling to water cooling, and in the winding method, moving from concentrated winding to distributed winding, as the output increases. This shift occurs around 8 to 10 kW. However, there is a paucity of empirical investigations examining these combinations to ascertain their optimality. In order to verify this trend, a verification model has been constructed which allows for the comparison of the capacity and weight of the motor and cooling system according to the vehicle’s required output and thermal performance. A comparison and verification of the combinations of winding methods (concentrated winding or segment conductor distribution winding) and cooling systems (water-cooled or air-cooled) was conducted using the model that had been constructed. In the motor designed for this study, when the maximum output of the vehicle was 35 kW or less (European A2 license), the total
Otaki, Ryota, Tsuchiya, Teruyuki, Sakai, Yu, Yamauchi, Takuya, Shimizu, Tsukasa
Technical Paper
Studying the Lean Burn Operation in Two-Wheelers to Increase Fuel Efficiency and Investigate the Use of Lean NOx Trap Catalyst (LNT) for Lean Burn System2024-32-005804/18/2025
This study offers an overview of the impact of lean burn technology in two-wheeler vehicles, specifically concentrating on enhancing the fuel economy and addressing the challenges associated with its adoption. Lean burn systems, characterized by a fuel-air mixture with a higher air content than stoichiometric ratio. The study focuses on technology which meets stringent emission standards while enabling the optimization of fuel efficiency. The lean burn system employs strategies to optimize air-fuel ratio using electronic fuel injection, ignition timing control, and advanced engine control algorithms like - updated torque modulation control algorithm for drivability, lambda control algorithm for rich and lean switch and NOx modelling algorithm for LNT catalyst efficiency tracking. The challenges related to lean burn systems, includes issues related to combustion stability, nitrogen oxide (NOx) emissions, and their impact on drivability, is summarized in the study. Mitigation strategies
Somasundaram, Karthikeyan, Sivaji, Purushothaman, John Derin, C, Vishal, Karwa, Manoj Kumar, S, Maynal, Rajesh
Technical Paper
Dynamic Analysis of Intake and Exhaust Valve Motion in a High-Performance 4-Stroke Engine. Part1 - Experimental Measurement of Valve Motion Using a High-Frequency Laser Sensor2024-32-008304/18/2025
The motion of the intake and exhaust valves plays a pivotal role in determining operational efficiency and performance, especially in high-specific power 4-stroke engines. At high rpm levels, the dynamic behavior of the valve may deviate from the kinematic model established during the design phase. This discrepancy arises due to the high accelerations and forces to which the valve and other components of the valvetrain system are subjected. Notably, under such conditions, the valve may detach from the cam profile at the conclusion of the opening stroke and can exhibit a bouncing behavior during the closing stroke. Moreover, the elasticity of all valvetrain system elements introduces additional complexities. Factors such as timing chain elongation, camshaft carrier deformation, and valve stem compression can contribute to a deviation in phase compared to the initially defined kinematics. Within this context, the direct measurement of the valves motion represents fundamental information
Grilli, Niccolò, Romani, Luca, Raspanti, Sandro, Bosi, Lorenzo, Ferrara, Giovanni, Trassi, Paolo, Fiaschi, Jacopo, Guarducci, Edoardo
Technical Paper
CFD Analysis of Pintle-Nozzle Spray for Swirl Chamber Type Small Diesel Engine -Application of Hole-Nozzle Atomization Model to Pintle-Nozzle2024-32-010904/18/2025
Swirl chamber combustion system is commonly used for IDI (In-Direct Injection) diesel engine. It is characterized by swirl combustion chamber arranged in cylinder head, main combustion chamber with shallow piston recess and connecting throat where fuel spray and flame mixture is ejected out from the swirl chamber to the main chamber [1]. Fuel is supplied in the swirl chamber and a pintle type nozzle is often used in this type engine as its simple structure and robustness for operating condition. In this paper, numerical simulation of a pintle nozzle spray was focused on and simulated results were compared with high speed photo data obtained in a constant volume vessel (CVV). Spray angle and tip penetration were mainly evaluated, but simulated angle and penetration could not be matched simultaneously to these characteristics of the pintle nozzle spray when conventional spray models were used for the simulation. To overcome this mismatch, “Multi-hole replacement model” was newly
Okazaki, Tadao, Fujiwara, Tsukasa
Technical Paper
Detailed Approach for Pre-Chamber Heat Release Analysis for the HSASI Pre-Chamber Spark Plug Using a Pressure Sensor Glow Plug2024-32-006304/18/2025
The hot surface-assisted spark ignition (HSASI) pre-chamber spark plug, which was developed at the Karlsruhe University of Applied Sciences, increases the dilution limit with excess air and the tolerance to residual gas in the pre-chamber compared to a conventional passive pre-chamber spark plug. In this study, the conventional glow plug which is integrated in the pre-chamber of the HSASI pre-chamber spark plug was replaced by a pressure sensor glow plug (PSG) from BERU. This allows for a detailed combustion analysis in the pre-chamber. The signal of the PSG was validated with a piezoelectric cylinder pressure sensor and a method to analyse the pre-chamber heat release was introduced. Experimental investigations were carried out on a single-cylinder gasoline engine. A series of operating points diluted with excess air and a variation in load were conducted. The gas flow rate through the orifices of the pre-chamber was calculated from the pressure difference between the pre-chamber and
Holzberger, Sascha, Kettner, Maurice, Kirchberger, Roland
Technical Paper
Effect of Ignition Position on Lean Limit of Main Chamber Combustion in Pre-Chamber Ignition2024-32-002204/18/2025
An engine was built in this study that enabled the conditions in a pre-chamber and in the main combustion chamber to be visualized simultaneously for the purpose of elucidating the mechanism of pre-chamber combustion. An investigation was made of how the state of pre-chamber combustion, including the location of initial flame generation and its subsequent propagation, influenced pre-chamber jet combustion. The state of pre-chamber combustion was intentionally varied by changing the position of pre-chamber ignition. As a result, it was found that changing the position of pre-chamber ignition varied the location where the pre-chamber flame occurred, how the flame propagated and the timing and strength of the flame jet that was ejected into the main chamber. The results revealed that these differences in the state of pre-chamber combustion markedly changed the rate of combustion fluctuation, combustion period, lean-burn limit and other combustion characteristics depending on the ignition
Onuma, Takeru, Yamada, Hiroto, Ugajin, Taisei, Shinozaki, Kaito, Tahara, Ryota, Iijima, Akira
Technical Paper
Experimental Investigation of n-C7H16/Ethanol Blended Fuels on Auto-ignition and Flame Propagation in High Temperature/Pressure Constant-Volume Combustion Vessel2024-32-005004/18/2025
This study aims to investigate the effect of ethanol blends on flame propagation and auto-ignition under high pressure and high temperature conditions. Experimental investigations are conducted using n-C7H16 / ethanol blends at various blending ratios (0, 5, 10, 20, 40, 70, and 100 vol%). The blends are premixed with air at stoichiometric ratios and ignited centrally in a cylindrical constant-volume combustion chamber (20-mm inner diameter, 80-mm long) under elevated temperature (500 K) and pressure (1.0 MPa) conditions. The results show that auto-ignition occurs at an ethanol blend ratio of 10% or less and ceases above 20%. Increasing the ethanol blend to 70% results in a slight change in flame propagation speed, with a noticeable delay at 100%. The pressure measurements show a peak of about 5.6 MPa at a blend ratio of 5%, which gradually decreases with increasing ratios. High-pass filtering reveals the maximum pressure fluctuation amplitude at the 5% blend ratio, indicating increased
Tateishi, Tokua, Yamaguchi, Riki, Shimokuri, Daisuke, Terashima, Hiroshi, Hara, Takaya, Honda, Yuya, Kawano, Michiharu
Technical Paper
Model-Based Calibration of ECU for Small Motorcycles2024-32-002404/18/2025
To deal with the emission regulations it is necessary to produce ECU control maps that maintain balance of emissions of HC, NOX, CO, engine power output and fuel consumption during the motorcycle development. We have recently introduced the Model-Based Calibration (hereafter as MBC) for calibration of ECU control maps for small motorcycles, which share a big chunk of the market. When introducing we aimed at such a method that can simulate stable temperature conditions necessary for the measurement in order to make it applicable to air-cooled engines predominantly used in small motorcycles. To decrease performance difference between the prototype and the mass-production, the newly developed method allows rewriting of control parameters such as the ignition timing using the mass-production ECU. The fully automated data acquisition along with the application of MBC permits continuous test operations even in nighttime and on holidays. Moreover, the MBC flow was made such a manner that
Fujiwara, Hirofumi, Maruyama, Atsushi, Kasai, Yoshiyuki
Technical Paper
Research on Basic Characteristics of a Two-Stroke Opposed Piston Engine2024-32-011204/18/2025
This study investigated the performance characteristics of a two-stroke opposed piston engine that is capable of constantly operating with high power output and high efficiency. An investigation was also made of the performance obtained by applying a pseudo uniflow condition as a measure against large hydrocarbon (HC) emissions owing to blow-by of unburned mixture, which is an issue of two-stroke engines. The test engine had a displacement of 127 cm3 and a bore and stroke of 48 x 70 mm. One-point and dual-point ignition systems were used, and regular gasoline was supplied as the test fuel using a carburetor-based fueling system. Experiments were conducted at engine speeds of 1500 and 3000 rpm at ignition timings of 45 deg. and 35 deg. before top dead center. The results showed that large quantities of HC emissions were emitted because stable combustion was not achieved. This revealed that a stronger uniflow condition must be applied as a countermeasure rather than a simple pseudo
Fukushima, Shumpei, Uehara, Ryota, Hayashi, Yoshiaki, Igarashi, Ryo, Tokita, Kazuho, Iijima, Akira
Technical Paper
Development of Cylinder Deactivation Control during Idle for Conventional Engines2024-32-001904/18/2025
This report examines the advancement and utilization of cylinder deactivation technology that enhances fuel efficiency in conventional engines without hardware modifications. It operates by halting fuel supply to some of the cylinders in multi-cylinder engines and increasing the output power of the remaining active cylinders to maintain an idle state. By implementing this technology in the mass-produced 90° V-twin engine, the U502, and deactivating one of its two cylinders, fuel consumption during idling is reduced by over 30%. The focus of this study is on the technology developed to minimize engine speed fluctuations during the transition to cylinder deactivation and reactivation for the engine. By making various modifications to the fuel injection control sequence and optimizing the throttle opening of each cylinder in idle and driving conditions, engine speed fluctuations were minimized. This allows users to reduce fuel consumption while maintaining the engine’s original
YANAGIDA, Shoji
Technical Paper
Optimization of Combustion Efficiency and Conversion Efficiency of Catalytic Converter in Spark-Ignited Engine using Taguchi Methods Robust Optimization Technique for Flex Fuel Application2024-32-012304/18/2025
Flex fuel vehicles (FFV) can operate effectively from E5 (Gasoline 95%, ethanol 5%) fuel to E100 (Gasoline 0%, ethanol 100%) fuel. It is necessary to meet the performance, drivability, emission targets and regulatory requirements irrespective of fuel mixture combination. This research work focuses on optimizing the combustion efficiency and conversion efficiency of catalytic converter of a spark-ignited less than 200 cc engine for FFV using Taguchi methods robust optimization technique. The study employs an eight-step robust optimization approach to simultaneously minimize engine out emissions and maximize catalytic converter efficiency. Six control factors including type of fuel, catalyst heating rpm, lambda (excess-air ratio), injection end angle, lambda controller delay, and ignition timing are optimized. Four noise factors like compression ratio, clearance volume, catalyst noble metal loading, and catalyst aging are also considered. Through approximately 100 physical experiments on
Vaidyanathan, Balaji, Arunkumar, Praveenkumar, Shunmugasundaram, Palani, Murugesan, Manickam, Jayajothijohnson, Vedhanayagam
Technical Paper
Enhancements in Hydrogen Low Pressure Injection on Small Two-Stroke Engines2024-32-004704/18/2025
The use of small 2-stroke crankcase scavenged engines running on hydrogen is very attractive for low power rates, when low cost and compact dimensions are the fundamental design constraints. However, achieving optimal performance with hydrogen fuel presents challenges, including uneven air-fuel mixtures, fuel losses, and crankcase backfiring. This research focuses on a small 50cc 2-stroke loop-scavenged engine equipped with a patented Low-Pressure Direct Injection (LPDI) system, modified for hydrogen use. Experimental results demonstrate performance comparable to the gasoline counterpart, but further optimizations are needed. Consequently, CFD-3D simulations are employed to analyses the injection process and guide engine development. The numerical analysis focuses on a fixed operating condition: 6000 rpm, Wide Open Throttle (WOT), with a slightly lean mixture and injection pressure fixed at 5 bar. A numerical model of the entire engine is set up with the primary objective of improving
Caprioli, Stefano, Schoegl, Oliver, Oswald, Roland, Kirchberger, Roland, Mattarelli, Enrico, Rinaldini, Carlo Alberto
Technical Paper
Fuel Film Measurement in a SI Gasoline Engine Using a Newly Developed MEMS Sensor2024-32-007104/18/2025
The previously developed capacitance sensor for detecting a liquid fuel film was modified to apply to the in-cylinder measurement. On the developed sensor surface, comb-shaped electrodes were circularly aligned. The capacitance between the electrodes varies with the liquid fuel film adhering. The capacitance variation between the electrodes on the sensor surface was converted to the frequency variation of the oscillation circuit. In the previous study, it was revealed that the frequency of the oscillation circuit varies with the variation of the liquid fuel coverage area on the sensor surface. The developed sensor was installed in the combustion chamber of the rapid compression and expansion machine, and the performance of the developed sensor was examined. Iso-octane was used as a test fuel to explore the sensor that had been developed. As a result, the adherence of the liquid fuel directly injected into the cylinder was successfully detected under the quiescent and motoring
Kuboyama, Tatsuya, Moriyoshi, Yasuo, Takayama, Satoshi, Nakabeppu, Osamu
Technical Paper
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