Browse Topic: Pressure

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Enhancing Tipper Stability During Descent with Dynamic Angle Adjustment2025-28-0276To be published on 11/06/2025
This study addresses critical challenges faced by tippers transporting bulk cargo during descent, focusing on two major risks: cargo displacement and rear axle lifting. Prolonged descents often lead to uncontrolled shifting of cargo, such as loose aggregates or soil, within the tipper body. This phenomenon, driven by gravity, momentum, and insufficient restraint systems, poses threats of cabin damage and unpredictable ejection of materials onto the roadway. Additionally, rear axle lifting occurs due to load imbalances, increasing pressure on the front steering axle. This results in front tire slippage and inefficient steering. To tackle these issues, the study proposes a novel approach involving dynamic adjustment of the tipper lift angle to align with the road descent angle. Synchronizing the trailer bed angle with the terrain slope minimizes gravitational forces on the cargo, stabilizes its center of gravity, and ensures consistent contact between the rear tires and the road surface
Vijeth, Abhishek, Bhosle, Devidas Ashok, Cherian, Roshni, Dash, Prasanjita
PTO Clutch Hydraulic Performance Evaluation Methodology Development & Correlation2025-28-0295To be published on 11/06/2025
This paper presents an analysis methodology developed to understand the impact of pressure spikes in off-highway applications, particularly during PTO (Power Take-Off) clutch engagement. These pressure spikes can adversely affect hydraulic subsystem components such as seals, gaskets, and valve operations. Assessing hydraulic system performance through physical trials can be cumbersome, resulting in longer development times and increased costs. To address this, a methodology was developed in a virtual environment to evaluate hydraulic system performance. The virtual method outlined in this paper is created in a 1D environment using an analytical approach to replicate the transient behavior of the system. The hydraulic system primarily includes a relief valve, solenoid valves, a pump, and a clutch. An analytical model was developed for the hydraulic system components with the right fidelity to accurately capture the transient behavior and magnitudes of pressure spikes. This methodology
Memane, Nilesh, Kumar, Suneel, Veerkar, Vikrant
Analysis of injected mass shot-to-shot dispersion and injection rate profile for a PFI injector in actual operating conditions2025-32-0019To be published on 11/03/2025
In order to improve engine emission and limit combustion instabilities, in particular for low load and idle conditions, reducing the injected fuel mass shot-to-shot dispersion is mandatory. Unfortunately, the most diffused approach for the hydraulic analysis of low-pressure injectors such as PFIs or SC R dozers is restrained to the mean injected mass measurement, since the use of conventional injection analysers is unfeasible. In the present paper, an innovative injection analyser is used to measure the injection rate and the injected mass of each single injection event, enabling a proper dispersion investigation of the studied system. The proposed instrument is an inverse application of the Zeuch’s method, which in this case is applied to a closed volume upstream the injector, with the injector being operated with the prescribed upstream-downstream pressure differential. Further, the injector can inject freely against air, thus enabling simultaneous analyses of the resulting spray
Postrioti, Lucio, Maka, Cristian, Martino, Manuel
Thermal Analysis and Effect of Cell Arrangement on Air Cooled Cylindrical Cell Battery Pack Performance2025-28-036110/30/2025
The arrangement of multiple cells within a battery pack is crucial to have an optimized thermal performance and pressure drop. This paper presents a comparative analysis of thermal battery cooling performance of an air-cooled battery pack using inline and staggered arrangement of 18650 sized cylindrical cells with different cell spacings. The key parameters such as air pressure drop and cell (average/maximum/minimum) temperatures are compared for operations at different C-rates, air inlet temperature, and air inlet velocities. The results demonstrate that the staggered configuration with optimal spacing offers better thermal performance and temperature distribution compared to the inline one. Specifically, the staggered setup with optimal gap achieves a lower cell average and maximum temperatures indicating more efficient cooling and uniform thermal distribution. This study highlights the advantages of battery spacing and configuration for improved thermal and pressure drop performance
Bharsakale, Yash, Nadge, Pankaj, Manna, Suvankar
Development of Capacitive Pressure Sensor for Automotives2025-28-038710/30/2025
Measurement plays a crucial role in the precise and accurate management of automotive subsystems to enhance efficiency and performance. Sensors are essential for achieving high levels of accuracy and precision in control applications. Rapid technical advancements have transformed the automobile industry in recent years, and a wide range of novel sensor devices are being released to the market to speed up the development of autonomous vehicle technology. Nonetheless, stricter regulations for reliable pressure sensors in automobiles have resulted from growing legal pressures from regulatory bodies. This work proposes and investigates a tribo electric nano sensor that is affected by a changing parameter of the separation distance between the device's primary electrode and dielectric layers. The system is being modeled using the COMSOL multiphysics of electrostatics and the tribo-electric effect. Open circuit electric potential and short circuit surface charge density are two of the
P, Geetha, K, Neelima, Sudarmani, R, C, Venkataramanan, Satyam, Satyam, Nagarajan, Sudarson
Impact of Air Pressure Load on HVAC Kinematic Mechanism2025-28-036810/30/2025
In Automobile AC system, HVAC is one of major component as it controls the air flow and air distribution based on cabin requirement. HVAC kinematics mechanism is used for controlling the air flow based on passenger requirement inside the cabin. The air flow movement inside HVAC has a severe impact on servo motor/cable torque which is controlling the mechanism. Simulation driven design method is widely used in world due to highly competitive automotive industry. Launching the product at the market within short span of time, with good quality and less cost is more challenging. Hence CAE/MBD based approach is more significant as it will reduce number of prototypes as well as the cost of testing. The objective of the analysis is to predict the HVAC servomotor torque required to operate the HAVC linkages under operating conditions. The air pressure load will have significant impact on damper face which will cause torque at CAM as well as servo lever center. The torque values at servo lever
Parayil, Paulson
Baltimore Urban Road Network Research: The Impact of Bridge Collapse on Different Groups of People and Transportation System Improvement Strategies2025-99-004310/17/2025
This paper studies the transportation demands of different stakeholders, namely urban residents, entrepreneurs and tourists. It also studies the construction of network model optimization functions and corresponding indicators, and analyzes what kind of impact the bridge collapse will have on different stakeholders. Urban residents attach great importance to convenience in their daily lives. They usually like to travel by walking or cycling. They also prefer to use public transportation facilities. Entrepreneurs mainly rely on the efficiency of goods transportation to develop their businesses. They pay more attention to the accessibility of commercial and industrial areas. Tourists, on the other hand, prefer convenient connections between tourist attractions and hotels, as this makes their visits more convenient. After the bridge collapsed, the traffic pressure shifted to other main roads, such as I-95 and I-895. This led to longer commuting times and a significant increase in
Xiang, Xiaohong, Ying, Rongrong, Zhou, Lin
Analysis of the Water Exit Process of a Vehicle Based on Fluid-Structure Interaction Analysis2025-99-000210/17/2025
The study investigated the fluid dynamics characteristics of a navigational body during emerging from water. It focus on the patterns of pressure and velocity changes in the flow field. Using numerical simulation methods, we explored the fluid-structure interaction between the navigational body and the surrounding water. It revealed the phenomenon of decreasing impact forces on the object’s surface over time and the resulting changes in surface pressure distribution. Additionally, the study demonstrated the dynamic evolution of the velocity field during emergence. This further elucidated the impact of flow state changes on the navigational body’s motion performance and stability. These findings would provide important theoretical foundations and technical support for optimizing the design of navigational bodies.
Zhang, Chaoyang, Zhang, Zhihua, Liu, Zongkui, Sui, Jiuling
Influence of Microtexture’s Parameters on Improving the Lubrication Performance of Crankpin Bearings in Engine04-19-02-000610/09/2025
The force of the solid contact (Fsc ) between the bearing surface and the shaft surface and the friction force (Ffri ) generated in the crankpin bearing have a great influence on the lubrication performance of the crankpin bearing in the engine. Therefore, the micro-circular texture (MCT) has been proposed and designed on the bearing surface of the crankpin bearing for ameliorating its lubrication performance. To evaluate the effectiveness of MCT in detail, based on the lubricating model of the crankpin bearing under the impaction of external load F 0, the influence of the density, depth (hMCT ), and radius (rMCT ) of MCT on the characteristics of the pressure (p) of oil film, thickness of oil film (h), force of solid contacts, and force of the friction in the crankpin bearing are also investigated, respectively. An algorithmic program written in a MATLAB environment is then applied to simulate the lubrication equations of the crankpin bearing and MCT. Some outstanding results of the
Jiao, Renqiang, Nguyen, Vanliem
Effect of Flow Speed and Turbulence on Methane Combustion in a Rapid Compression Machine2025-01-039310/07/2025
Recent experimental work from the authors’ laboratory demonstrated that applying a boosted current ignition strategy under intensified flow conditions can significantly reduce combustion duration in a rapid compression machine (RCM). However, that study relied on spark anemometry, which provided only localized flow speed estimates and lacked full spatial resolution of velocity and turbulence near the spark gap. Additionally, the influence of turbulence on combustion behavior and performance across varying flow speeds and excess air ratios using a conventional transistor-controlled ignition (TCI) system was not thoroughly analyzed. In this study, non-reactive CFD simulations were used to estimate local flow and turbulent velocities near the spark gap for piston speeds ranging from 1.2 to 9.7 m/s. Simulated local velocities ranged from 0.7 to 96 m/s and were used to interpret experimentally observed combustion behavior under three excess air ratios (λ = 1.0, 1.4, and 1.6). Combustion was
Haider, Muhammad.Shaheer, Jin, Long, Yu, Xiao, Reader, Graham, Zheng, Ming
Bridging Fundamental Combustion Analysis and Engine Knock Behavior -1st Report, CFR Engine Test for Various RON Fuels2025-01-039110/07/2025
A collaborative study was conducted to bridge the gap between fundamental combustion research and engine-scale observations of knock in spark-ignition (SI) engines. Using Primary Reference Fuels (PRFs) with Research Octane Numbers (RON) of 80, 90, and 100, experiments were carried out with a Cooperative Fuel Research (CFR) engine at air-fuel ratio, λ = 1.0, focusing on knock onset conditions in terms of unburned gas pressure and temperature. In the engine tests, pressure traces under knocking conditions were analyzed to identify knock onset and to estimate the corresponding unburned gas temperature history. Results showed that the pressure at knock onset varies clearly with PRF value: higher RON fuels exhibited knock onset at higher pressures, likely due to changes in compression ratio applied to match standard RON test procedures. In contrast, the unburned gas temperature conditions showed partial overlap across different PRFs, but with a tendency for higher RON fuels to experience
Yasutake, Yuki, Misono, Katsuhiro, Suzuki, Yoshikatu, Naiki, Taketora, Watanabe, Manabu, Moriyama, Hinata, Morii, Youhi, Tsunoda, Akira, Maruta, Kaoru
Enhancing Robustness of Electro-Hydraulic Brake-by-Wire Actuators via Linear Active Disturbance Rejection Control2025-01-034109/15/2025
In recent years, motorsport has increasingly focused on environmental concerns, leading to the rise of hybrid and fully electric competitions. In this scenario, electric motors and batteries take a crucial role in reducing the environmental impact by recovering energy during braking. However, due to inherent limitations, motors and battery cannot fully capture all braking power, necessitating the use of standard friction brakes. To achieve an efficient balance between electric motors and friction brakes, the brake pressure can no longer be directly controlled by the driver. Instead, it must be computed by the Vehicle Control Unit (VCU) and sent to a smart actuator, i.e. the Brake-By-Wire (BBW), which ensures that the required pressure is applied. The standard approach to achieve precise pressure control is to design a nested Proportional-Integral-Derivative (PID) control architecture, which requires an accurate nominal model of the system dynamics to meet the desired tracking
Gimondi, Alex, Dubbini, Alberto, Riva, Giorgio, Cantoni, Carlo
Effect of Pressure Losses and Reynolds Number on Active Grille Shutter Characteristics and Its Prediction2025-01-505909/10/2025
In the present article it is investigated why active grille shutters (AGS) can have very different aerodynamic characteristics, ranging from progressive to strongly degressive, and which factors influence them. For this purpose, the authority concept known from the field of heating, ventilation, and air-conditioning (HVAC) is referred to. According to this theory, the control characteristics of dampers depend primarily on the ratio of the pressure losses at the fully open damper to the pressure losses of the rest of the system. The adaptation of the concept to the automotive field shows that, in addition to the pressure losses, the geometry of the cooling air ducting plays a decisive role in motor vehicles. The effect of driving speed and fan operation on the characteristic curves is also being investigated. In addition, authority theory can also be used to derive the conditions under which the opening characteristic curve of an AGS provides a good prediction of the real characteristic
Wolf, Thomas
Comparison of Ignition Modes to Enable Ammonia Combustion Engines: Dual Fuel, Multi-Spark and Pre-Chamber2025-24-000509/07/2025
This study presents a CFD-based evaluation of ignition strategies for enabling ammonia combustion in a light-duty internal combustion engine. The model was first validated against experimental data for both pure ammonia spark ignition and dual-fuel ammonia-diesel compression ignition cases. Upon validation, three ignition strategies were investigated: dual-fuel compression ignition with sixty percent ammonia energy fraction, and multi-spark and passive pre-chamber ignition under stoichiometric conditions. Simulations were used to assess combustion phasing, efficiency, and emissions characteristics. The dual-fuel mode enabled stable ignition but resulted in incomplete combustion, with three-dimensional contours revealing that central regions of the chamber remained largely unburned, contributing to high ammonia slip and highlighting the need for further optimization of spray targeting and combustion chamber design. The multi-spark strategy achieved the highest efficiency through rapid
Shafiq, Omar, Menaca, Rafael, Liu, Xinlei, Uddeen, Kalim, Tang, Qinglong, Turner, James, Im, Hong G.
Numerical Investigation on an Injection strategy Optimization for Dual Fuel Marine Engine Fuelled by Ammonia2025-24-001309/07/2025
In the context of greenhouse gas emissions (GHG) reduction the most viable short-term solution in the maritime sector is the use of renewable carbon-free fuels. Among these, ammonia represents a possible alternative in compression ignition (CI) engines operating in dual fuel (DF) mode. Although, such fuel features low chemical reactivity, especially in lean mixtures, resulting in poor combustion efficiency, exhaust ammonia slip and low engine performance, DF combustion can be an interesting strategy to overcome such limitations. In this work a wide numerical examination of diesel injection strategies is presented, while ammonia acts as the primary fuel with energy supply around 80%. Since the original marine engine, fuelled with natural gas (NG), presents a single diesel injection, firstly, a pilot injection is added and different diesel mass shares between pilot and main are investigated, by varying the injection rate shape and the pilot start of injection (SOI). Calculations are
Cameretti, Maria Cristina, De Robbio, Roberta, Palomba, Marco
Enabling Near-Zero Emissions and Superior Efficiency in Large-Bore, Medium-Speed Engines with a Hydrogen-Argon Power Cycle2025-24-000109/07/2025
Combustion engines operating on a hydrogen-argon power cycle (H-APC) offer potential for superior thermal efficiency with true zero exhaust emissions. The high specific heat ratio of argon allows extrapolation of the theoretical efficiency of the Otto cycle to almost 90%. However, this potential is significantly constrained by challenges in combustion control, excessive thermal loading, and system integration, particularly regarding argon recovery. This study investigates these trade-offs, within the context of real-world engine-based peaking power plants. An experimentally validated 1D-simulation model of a prototype Wärtsilä 20 DF engine serves as reference for analysis of a retrofit incorporating a closed-loop argon cycle, with dedicated H₂ and O2 injectors, a water condenser and water separator. Engine performance is evaluated at reference operating point of 75% load, considering pre-ignition, peak pressure and exhaust temperature constraints, condenser limitations, and impurity
Ahammed, Sajid, Ahmad, Zeeshan, Mahmoudzadeh Andwari, Amin, Kakoee, Alireza, Hyvonen, Jari, Mikulski, Maciej
Effects of Varying the Air-Fuel Equivalence Ratio at Different EGR-Rates on a Medium-Speed LNG-Diesel Dual-Fuel Engine2025-24-004109/07/2025
The dual-fuel combustion process, which is offered as a retrofit solution for conventional diesel engines by various manufacturers, represents an option for reducing emissions from internal combustion engines and is already available today. Current dual-fuel engines run on liquefied natural gas (LNG), which is usually of fossil origin. Due to the existing infrastructure and the possibility of producing LNG by means of electrolysis and methanation, LNG can already be produced in a 100% climate-neutral way and thus make a contribution to climate neutrality in the shipping industry. The adoption of exhaust gas recirculation (EGR) systems in the maritime sector became more significant in 2020 following the enforcement of the sulphur emission cap. By lowering the sulphur content in the fuel, technologies in the exhaust tract are also conceivable without the use of expensive scrubber systems. Dual-fuel LNG/diesel engines are typically operated in lean-burn mode to reduce the risk of knocking
Seipel, Pascal, Glauner, Manuel, Dinwoodie, Jules, Buchholz, Bert
Experimental Investigation of the Comparison between Helium and Hydrogen Jets Exiting a DI Outward-Opening Injector via Schlieren Technique2025-24-006809/07/2025
This paper deals with the hydrogen-to-helium jets comparison within the framework of the assessment of helium as a potential hydrogen surrogate. The comparison is centred on the assessment of the combined action of pressure ratio with gas properties on the dynamics of the jet exiting an outward-opening injector. The shots are performed at injection pressures and backpressures ranging from 21 to 36 bar and from 1.2 to 5 bar, respectively. The Schlieren technique is deployed to capture the jets images. The study demonstrates that at certain pressure ratios helium is an appealing solution bridging the lab safety with fidelity to hydrogen-like jet behaviour. Decreasing pressure ratio minimizes the hydrogen-to-helium difference in axial penetration and area, enabling helium to yield a hydrogen-like development. The findings underscore the impact of the pressure ratio on how the gas properties, such as density and diffusivity, dictate the evolution of the axial propagation and area
Coratella, Carlo, Tinchon, Alexis, Hespel, Camille, Dober, Gavin, Foucher, Fabrice
Laser Welding for Polymer Tubing: A New Solution for Adhesive- and Additive-Free JoiningTBMG-5377809/01/2025
Medical tubing is an essential component of countless healthcare applications, from intravenous (IV) and oxygen lines to catheters and diagnostic equipment. These tubes, often made of clear flexible polymers, must be produced to exacting standards: free of contaminants, strong under pressure, and biocompatible. However, the joining process to connect these tubes can introduce significant manufacturing challenges.
New Copper Alloy Could Provide Breakthrough in Durability for Military SystemsTBMG-5359108/01/2025
U.S. Army researchers, in collaboration with academic partners, invented a stronger copper that could help advance defense, energy and aerospace industries thanks to its ability to endure unprecedented temperature and pressure extremes. Extreme materials experts at the U.S. Army Combat Capabilities Development Command (DEVCOM) Army Research Laboratory built on a decade of scientific success to develop a new way to create alloys that enable Army-relevant properties that were previously unachievable. An alloy is a combination of a metal with other metals or nonmetals.
Investigation of Expansion Characteristics of Convergent–Divergent Nozzles with a Variable Geometry Sudden Expanded Duct01-18-02-001007/09/2025
In recent years, there has been a significant rise in research focused on estimating the base pressure (Pb) characteristics of convergent–divergent nozzles with sudden expansion regions. This study explores the use of geometrical parameters as a control strategy for nozzles experiencing abrupt expansion at supersonic Mach numbers within an axisymmetric duct. It focuses on four distinct novel expansion duct configurations: square nozzle (SN), step square nozzle (SSN), curved nozzle (CN), and double curved nozzle (DCN). In this work, the high-speed compressible flow investigation is carried out numerically using control volume method on the nozzle with a fixed area ratio (AR) and L/D nozzle. Standard k-ε turbulence model is used in the analysis to access the recirculation region formed near the nozzle walls. The recirculation zone directly influences the Pb and shock cell. For NPR range from 2 to 10, SSN and CN shows an increase in Pb, which further increases the thrust and decreases the
Raj, R. Jini, Kumar, P. Deepak, Panchksharayya, D. V., Kousik Kumaar, R., Praveen, N.
In Situ Observation of Different Soot Layers in a Model Filter Channel during Its Regeneration2025-01-031207/02/2025
In order to comply with increasingly stringent emission regulations and ensure clean air, wall-flow particulate filters are predominantly used in exhaust gas aftertreatment systems of combustion engines to remove reactive soot and inert ash particles from exhaust gases. These filters consist of parallel porous channels with alternately closed ends, effectively separating particles by forming a layer on the filter surface. However, the accumulated particulate layer increases the pressure drop across the filter, requiring periodic filter regeneration. During regeneration, soot oxidation breaks up the particulate layer, while resuspension and transport of individual agglomerates can occur. These phenomena are influenced by gas temperature and velocity, as well as by the dispersity and reactivity of the soot particles. Renewable and biomass based fuels can produce different types of soot with different reactivities and dispersities. Therefore, this study focuses on the influences of soot
Desens, Ole, Hagen, Fabian P., Meyer, Jörg, Dittler, Achim
Application of Sustainable Aviation Fuels in Compression Ignition Aviation Engines: In-Flight Investigations2025-01-031707/02/2025
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
Impulse Testing of Hydraulic Tubing and Fittings, S-N CurveAS4265A (Current)06/30/2025
This aerospace test standard establishes the requirements and procedures for evaluating and comparing the impulse fatigue performance of high pressure hydraulic fittings and tubing. This test method may be used to test similar fluid system components, if desired.
G-3, Aerospace Couplings, Fittings, Hose, Tubing Assemblies
An Experimental Study on Aqueous Ammonia and Diesel Dual-Fuel Combustion with Ignition Improving Additives in a Compression Ignition Engine2025-01-023106/16/2025
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
Development of Simple Models for Performance Estimation of a Spark Ignition Engine Fueled with Ammonia and Hydrogen2025-01-023806/16/2025
In engine development, it is needed to investigate engine performance under a lot of conditions. This is called the adaptability test, and it takes a lot of times, money, and manpower. Therefore, decreasing the test is aspired and constructing models that estimate the engine performance is effective for early adoption of ammonia engines. In this research, factors determining the thermal efficiency of a spark ignition engine fueled with ammonia/hydrogen mixtures were investigated and two simple models to estimate the performance were constructed. A diesel based four-stroke single-cylinder spark ignition engine with a displacement volume of 412 cm3 was used. Different compression ratios ε and two pistons with different squish areas were used. Experiments were conducted for total equivalence ratio of 1.0, while changing the LHV (lower heating value) ratio of ammonia and hydrogen. It is shown that higher compression ratio and larger squish velocity expanded the stable operation range of
Ichikawa, Aya, Ogura, Yuto, Yanaoka, Kazuki, Gonzalez Palencia, Juan, Kambara, Shinji, Araki, Mikiya
Numerical Investigation into the Combustion and Emission Characteristics of Ammonia Direct Injection Mechanism2025-01-024106/16/2025
The effects of diesel and the ammonia ratio on the emissions and combustion characteristics of ammonia utilized in AMMONIA direct injection (AMMONIA-Di) engines were investigated through experimental and numerical investigations. A rapid compression expansion machine (RCEM) modified to facilitate the dual direct injection fuel (diesel-ammonia) - compression ignition (CI) method was used to conduct the experiment. A compression ratio (CR) of 19 and an ammonia energy percentage ranging from 10% to 90% were used in the experiment. Changes were made to the start of injection (SOI) from 0o to 40o before top dead center (BTDC) in order to find the best auto-ignition properties of ammonia. In order to facilitate auto-ignition, the diesel’s SOI was maintained at 10o BTDC. Computational fluid dynamics (CFD) modeling was used to establish the detailed emission propagation during the combustion process. During the expansion step, ammonia goes through a second stage of combustion, demonstrating
Setiawan, Ardhika, Lim, Ocktaeck
Low-Cost Mobile Hydrogen Refuelling Stations: A Cost-Effective Solution for India's Sustainable Transportation2025-01-018706/16/2025
Low-Cost Mobile Hydrogen Refuelling Stations: A Cost-Effective Solution for India's Sustainable Transportation” The likely depletion of fossil fuel reserves in the next fifty years and growing environmental concerns caused by petroleum fuel-based vehicles highlight the urgent need for sustainable alternatives. India, a developing country, requires a significant amount of energy to sustain its growth, most of which is imported. Hydrogen is one of the cleanest fuels and offers sustainable pathways to a low-carbon future. The government of India has already launched a Green Hydrogen mission and has set up a very ambitious target for 2030. However, the absence of adequate refueling infrastructure is a significant blockade to India's widespread adoption of hydrogen-powered vehicles. The mobile hydrogen refueling station (MHRS) is a flexible system that enables lower initial capital costs than fixed hydrogen refueling stations and allows for the gradual build-up of hydrogen mobility fleets
Mathur, Animesh, Nayak, Ajay, Kumar, Naveen
NVH Improvement of Transmission Electric Oil Pump with Uneven Pitch Control2025-01-025206/16/2025
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
Higher Content n-Butanol Blending Ratios in Diesel Fuel Spray and Combustion Characteristics: Addressing Oxygenated Fuel Challenges with Spark-Assisted Combustion Strategies2025-01-021006/16/2025
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
Automobile Wheel Alignment and Wheel Balancing, Second EditionR-59106/12/2025
With over thirty years of hands-on experience in designing, developing, and patenting products in the wheel alignment industry, the author brings invaluable expertise to the second edition of this essential guide. Perfectly suited for mechanics, technicians, engineers, and even vehicle owners, this book goes beyond the basics to offer a comprehensive understanding of wheel alignment and its critical role in vehicle performance. The importance of proper wheel alignment and balancing cannot be overstated—incorrect alignment leads to premature tire wear and reduced safety. This updated edition provides in-depth coverage on wheel alignment techniques for light vehicles, commercial trucks, and trailers, with clear illustrations to help readers recognize and address various types of tire wear. The book explores everything from the mechanics of alignment to the impact of air pressure and tire rotation on longevity. With the growing need for vehicle maintenance, this guide empowers
R., Mananathan
Gaining a Competitive Edge with Functionally Integrated ComponentsTBMG-5321906/01/2025
Machine builders are under intense pressure to keep engineering time in line with shorter delivery schedules and materials, assembly, and inventory cost considerations. Machine builders are also striving to make equipment smaller, lighter, higher-performing and easier for their customers to maintain. While functionally integrated products have been available for a long time, they are more vital today than ever for machine builders and end users to improve processes and products. And there are more options available to provide solutions.
Development of an Intelligent Instrumented Tire for Real-Time Hydroplaning Risk Estimation10-09-03-002705/21/2025
This study introduces an innovative intelligent tire system capable of estimating the risk of total hydroplaning based on water pressure measurements within the tread grooves. Dynamic hydroplaning represents an important safety concern influenced by water depth, tread design, and vehicle longitudinal speed. Existing intelligent tire systems primarily assess hydroplaning risk using the water wedge effect, which occurs predominantly in deep water conditions. However, in shallow water, which is far more prevalent in real-world scenarios, the water wedge effect is absent at higher longitudinal speeds, which could make existing systems unable to reliably assess the total hydroplaning risk. Groove flow represents a key factor in hydroplaning dynamics, and it is governed by two mechanisms: water interception rate and water wedge pressure. In both the shallow water and deep water cases, the groove water flow will increase as a result of increasing the longitudinal speed of the vehicle for a
Vilsan, Alexandru, Sandu, Corina, Anghelache, Gabriel, Warfford, Jeffrey
Experimental Investigation of Carbon Nanotube Additives Effect on Performance and Emission of a High-Injection Pressure Common Rail Diesel Engine03-18-03-002005/16/2025
Due to the continuous decrease in fossil fuel resources, and drawbacks of some biofuel properties, in addition to restricted environmental concerns, it becomes a vital manner to innovate some approaches for energy saving and emission reduction. One of the promising approaches is to enhance the fuel properties via adding nanoparticles. Carbon nanotubes (CNTs) blended with biofuels get extensive investigations by researchers using conventional diesel engines at relatively limited operating regimes. The objective of this work is to extend these studies using diesel fuel, rather than biofuels, on a high-injection pressure (1400–1600 bar) common rail diesel engine at wide operating conditions and higher CNT concentrations. Experimental results show an increase in peak pressure up to 24.46% than pure diesel when using 100 ppm CNTs concentration. Also, BSFC has decreased by 33.19%, and BTE increased by 54.2% compared to pure diesel fuel at high speeds and loads. NOx and CO2 emissions raised
Moaayet, Sayed, Neseem, Waleed Mohamed, Amin, Mohamed Ibrahim, Shahin, Motasem Abdelbaky
Characterize the Sound Field Generated from a Vehicle Horn by Pellicular Analysis2025-01-005805/05/2025
To predict the sound field produced by a vehicle horn requires a good source representation of it in the full vehicle model. This paper investigates the characterization of a physical vehicle horn by an inverse method called pellicular analysis. To implement this method, firstly an acoustic testing is performed to measure the sound pressure radiated from the horn at a certain number of microphone locations in a free field environment. Based on the geometry of a virtual horn, the locations of each microphone and measured sound pressure data, pellicular analysis is adopted to recover a set of vibration pattern of the virtual horn. The virtual horn and the recovered vibration information are then incorporated in a full vehicle numerical model to simulate its exterior sound field. The validity of this approach is confirmed by comparing the prediction for a horn in a production vehicle to the corresponding physical test which is required to meet the Brazilian regulation CONTRAN 764/2018.
Yang, Wenlong, Melo, Andre
Experimental Investigation into Modulated Aeroacoustic Cabin Noise Arising from Unsteady Flow Conditions2025-01-002905/05/2025
The unsteady wind conditions experienced by a vehicle whilst driving on the road are different to those typically experienced in the steady-flow wind tunnel development environment, due to turbulence in the natural wind, moving through the unsteady wakes of other road vehicles and travelling through the stationary wakes generated by roadside obstacles. This paper presents an experimental approach using a large SUV-shaped vehicle to assess the effect of unsteady wind on the modulated noise performance, commonly used to evaluate unsteady wind noise characteristics. The contribution from different geometric modifications were also assessed. The approach is extended to assess the pressure distribution on the front side glass of the vehicle, caused by the aerodynamic interactions of the turbulent inflow in straight and yawed positions, to provide insight into the noise generation mechanisms and differences in behaviour between the two environments. The vehicle response to unsteady wind
Jamaluddin, Nur Syafiqah, Oettle, Nicholas, Staron, Domenic
GPU-Accelerated Aeroacoustic Simulations of HVAC Duct Configurations2025-01-013305/05/2025
Large eddy simulations (LES) of two HVAC duct configurations at different vent blade angles are performed with the GPU-accelerated low-Mach (Helmholtz) solver for comparison with aeroacoustics measurements conducted at Toyota Motor Europe facilities. The sound pressure level (SPL) at four near-field experimental microphones are predicted both directly in the simulation by recording the LES pressure time history at the microphone locations, and through the use of a frequency-domain Ffowcs Williams-Hawking (FW-H) formulation. The A-weighted 1/3 octave band delta SPL between the two vent blades angle configurations is also computed and compared to experimental data. Overall, the simulations capture the experimental trend of increased radiated noise with the rotated vent blades, and both LES and FW-H spectra show good agreement with the measurements over most of the frequency range of interest, up to 5,000Hz. For the present O(30) million cell mesh and relatively long noise data collection
Besem-Cordova, Fanny M., Dieu, Donavan, Wang, Kan, Brès, Guillaume A., Delacroix, Antoine
Study on the Aspiration Properties of Glassrun Seal System under Time-Varying Pressure Difference2025-01-003005/05/2025
When a vehicle is driven at high speed, there exists intricate flow pattern and vortex shedding at the side window area with intense pressure fluctuation. A significant dynamic pressure difference between the vehicle's exterior and interior can render the side window sealing system vulnerable to aspiration. This susceptibility can lead to the generation of leakage noise, adversely affecting acoustic comfort in the vehicle's cabin. This paper delves into the aspiration properties of glassrun seal system under time-varying pressure difference. A nonlinear finite element model of the glassrun seal was established to simulate the quasi-static deformation of the sealing strip during installation process, which aims to obtain the deformed geometric shape and residual stress after this process. Then, the exterior flow field of the glassrun sealing area of a simplified vehicle model was calculated with CFD simulation to obtain the hydrodynamic pressure excitation acting on the outer surface of
Li, Hanqi, He, Yinzhi, Zhang, Lijun, Zhang, Yongfeng, Yu, Wuzhou, Jiang, Zaixiu, Blumrich, Reinhard, Wiedemann, Jochen
Comprehensive Analysis and Optimization of Door Closing Sound Quality of a Heavy Truck2025-01-006605/05/2025
Based on the objective and subjective experiment and finite element analysis, the influencing factors on the door closing sound quality of a heavy truck is analyzed and optimized. Results show that the loudness and sharpness can be reduced by increasing stiffness and damping of the door. The sound quality can be enhanced by increasing the pressure release area, which can decrease the air pressure resistance of dooring closing. By adding holes on the inner liner and changing the pressure release location, the dooring closing air pressure resistance is reduced from 289 Pa to 181 Pa. In terms of the rebound sound, the sound level is positively related to the door closing force. Increasing the protrusion height and decreasing the stiffness of the vibration absorber of the handle can improve the rebound sound quality. Optimizing the absorbers on both ends of the handle and adding damping material can decrease the loudness by 47.8%, reduce the cavity sound, reduce the rattle and improve the
Wang, Jian, Zhang, Yongshen, Feng, Lei, Xie, Chenhao, Lin, Jiewei, Sun, Changchun
Tonal Noise Investigation of Automotive HVAC Systems: A Hybrid Method2025-01-002705/05/2025
There is no need to recall how the electrification trend of transport facilities has tightened the requirements around acoustic comfort. Within the automotive industry, these targets are more challenging for Heating, Ventilation and Air Conditioning systems for which passengers are in the frontline of noise emissions inside the car cabin. The complexity of the requirements and specifications set by car manufacturers and suppliers stems from a dual aspect. First is quantitative based on the sound pressure level, whether it's the overall level or 1/3 octave band spectra. The second is purely subjective, based on the perceived noise quality by stakeholders and final customers worldwide. During development phases, low tonal noises are frequently encountered on these systems which might induce discomfort to the passengers. The experimental investigations usually point to an aerodynamic origin, which prompted this research activity. The purpose of this work is to analyze and understand the
Bennouna, Saad, Alaoui, Mohamed, Henner, Manuel
Assignment Criteria for Function Allocation to Commercial Aviation System Security Domains2025-01-015605/02/2025
Aircraft cabin management is characterized by operational and business processes. Both are defined as a logical sequence of activities that occur during the flight. While the operational process includes activities to ensure flight safety, such as take-off, cruise and landing, the business process activities are related to adding value to the customer, i.e. the passenger. They are to be certified by the authority as a part of the aircraft type certification. These processes are defined by the airline and are described as part of the airline’s business model. While the scope of operational processes for passenger safety within the aircraft cabin should remain as unchanged as possible, the increasing competitive pressure on airlines is leading to a constantly rising number of services in the cabin. To prevent compromising cabin safety from increased cabin crew workload during the cruise phase, there is a growing trend toward digitizing operational and business processes. The digitized
Hintze, Hartmut, Blecken, Marvin, God, Ralf, Pereira, Daniel
Study on the Optimal Pre-Chamber Geometry for Active Pre-Chamber Gas Engines2024-32-002304/18/2025
In a pre-chamber engine, fuel in the main-chamber is ignited and combusted by the combustion gas injected from the pre-chamber. Therefore, further fuel dilution is possible and thermal efficiency can be also improved. However, adding a pre-chamber to an engine increases the number of design parameters which have a significant impact on the main combustion and the exhaust gas. Then, in this study, the optimum geometry of the pre-chamber in an active pre-chamber gas engine was investigated. The considered parameters were the volume of pre-chamber, the diameter of a nozzle hole, and the number of nozzle holes. 18 types of pre-chambers with different geometries were prepared. Using these pre-chambers, engine experiments under steady conditions were conducted while changing the conditions such as engine speeds, mean indicated pressure and air excess ratio. Based on the experimental data, neural network models were constructed that predict thermal efficiency, NOx and CO emissions from the
Yasuda, Kotaro, Yamasaki, Yudai, Sako, Takahiro, Takashima, Yoshitane, Suzuki, Kenta
Effects of Hydrogen Addition on Spark Knock Suppression under High Engine Speed and Boosted Conditions2024-32-010804/18/2025
The effect of hydrogen addition on spark knock suppression under high engine speed (4800 rpm) was investigated at the intake pressures of 96 kPa and 120 kPa. The experimental results showed that hydrogen addition has a slight effect on advancing the knock limit at 96 kPa, whereas a greater spark knock suppression effect can be achieved by increasing the intake pressure. To elucidate the influences and differences of hydrogen addition on the ignition process under low and high intake pressures, chemical kinetic analyses were performed using a two-zone combustion model. The calculation results showed that the reduction of heat release in the end gas resulting from the consumption of OH radicals by hydrogen can only be achieved at the initial stage of the ignition process. This leads to the smaller knock suppression effect at low intake pressures, where a remarkable heat release at this stage is absent. On the other hand, an increase in intake pressure results in a remarkable heat release
Goto, Jun, Ueno, Yoshito, Kobashi, Yoshimitsu, Shibata, Gen, Ogawa, Hideyuki, Kojima, Kentaro
Experimental Study on Thermo-Catalytic Ammonia Decomposition into Hydrogen2024-32-011804/18/2025
In order to rapidly achieve the goal of global net-zero carbon emissions, ammonia (NH3) has been deemed as a potential alternative fuel, and reforming partial ammonia to hydrogen using engine exhaust waste heat is a promising technology which can improve the combustion performance and reduce the emission of ammonia-fueled engines. However, so far, comprehensive research on the correlation between the reforming characteristic for accessible engineering applications of ammonia catalytic decomposition is not abundant. Moreover, relevant experimental studies are far from sufficient. In this paper, we conducted the experiments of catalytic decomposition of ammonia into hydrogen based on a fixed-bed reactor with Ru-Al2O3 catalysts to study the effects of reaction temperature, gas hour space velocity (GHSV) and reaction pressure on the decomposition characteristics. At the same time, energy flow analysis was carried out to explore the effects of various reaction conditions on system
Li, Ze, Li, Tie, Chen, Run, Li, Shiyan, Zhou, Xinyi, Wang, Ning
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
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
Numerical Studies on the Relation between the Multiple Auto-Ignition and Pressure Wave in the Premixed Charge2024-32-007904/18/2025
The relation between the multiple auto-ignition in the premixed charge with fuel concentration distribution and associated pressure wave are numerically investigated. This study assumes that the auto-ignition phenomenon in the end-gas of PCCI combustion, a next-generation combustion method which is expected to achieve both low fuel consumption and low emissions at a high level. Detailed numerical analysis considering the elementary chemical reactions of the compressible reacting fluid flow described in the one-dimensional coordinate system with high spatial and time resolution was performed to clarify the detailed phenomena of the onset of the multiple auto-ignition and the pressure wave propagation in the gas.
Iizumi, Kota, Yoshida, Kenji
Aerospace Fluid Systems and Components – Pressure and Temperature ClassificationsAS2001B (Current)04/14/2025
This document establishes the temperature types and pressure classes that are commonly used in aerospace fluid systems. The temperature types and pressure classes are equivalent, but not identical, to the SI units defined in MA2001 (ISO 6771). For exact conversion use NAS 10000.
G-3, Aerospace Couplings, Fittings, Hose, Tubing Assemblies
Investigation of the Blockage Phenomenon in Closed Wall Wind Tunnels During the Testing of Bluff Automotive Bodies with Large Wakes in Yawed Configurations2025-01-878604/01/2025
The difficulties of testing a bluff automotive body of sufficient scale to match the on-road vehicle Reynolds number in a closed wall wind tunnel has led to many approaches being taken to adjust the resulting data for the inherent interference effects. But it has been very difficult to experimentally analyze the effects that are occurring on and around the vehicle when these blockage interferences are taking place. The present study is an extension of earlier works by the author and similarly to those studies uses the computational fluid dynamics analysis of three bodies that generate large wakes to examine the interference phenomena in solid wall wind tunnels and the effects that they have on the pressures, and forces experienced by the vehicle model when it is in yawed conditions up to 20 degrees. This is accomplished by executing a series of CFD configurations with varying sized cross sections from 0.4% to 14% blockage enabling an approximation of free air conditions as a reference
Gleason, Mark, Riegel, Eugen
Capillary Transport Analysis in Macro-Homogeneous Diffusion Media of PEM Fuel Cells2025-01-854604/01/2025
The interplay of electrochemistry, two-phase flow, and heat transfer generates complex transport phenomena within the porous materials of fuel cells that are not yet fully understood. This lack of comprehensive understanding complicates the modeling of liquid water transport, which is critical because the hydration of the polymer electrolyte membrane significantly impacts the cell performance. The liquid water transport mechanisms in porous media can be explained by capillary force, hydraulic permeation and gravity effects, as well as water condensation and evaporation. In general, the liquid water transport is mainly driven by the capillary force, while body forces, such as gravity, do not significantly affect its momentum. Due to limited experimental data on capillary pressure and saturation in gas diffusion media, the Leverett approach has been widely used for modeling liquid water transport in PEMFCs. The Leverett approach is a polynomial fitting of capillary pressure data for
Marra, Carmine, Croci, Federico, Fontanesi, Stefano, Berni, Fabio, D'Adamo, Alessandro
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