Browse Topic: Pressure

Items (9,184)
This SAE Aerospace Recommended Practice (ARP) provides a procedure for obtaining filter patch test samples from the following types of aerospace non-rotating hydraulic equipment: Mechanical/Hydraulic Units Electro/Hydraulic Units Pneumatic/Hydraulic Units
A-6C1 Fluids and Contamination Control Committee
The lateral and longitudinal dynamics of passenger car tyres are critical to overall vehicle safety, handling, and stability. These characteristics directly influence braking, acceleration, and cornering performance. This study investigates the impact of key input parameters, namely inflation pressure, vertical load, and inclination angle, on tyre behaviour using a dual approach: Indoor testing with a Flat-Trac CT+ (FTCT+) and Outdoor evaluation using a skid trailer. Lateral dynamics are evaluated at slip angles to analyze lateral force and aligning moment characteristics. The influence of inclination angle, pressure, and load is quantified through cornering stiffness and aligning stiffness. The tests are conducted in both sweep and steady-state modes. To maintain data consistency, all tests use tyres of a single specification sourced from the same production batch. Longitudinal behaviour of a tyre is characterized by various parameters such as peak friction coefficient, sliding
Sethumadhavan, ArjunDuryodhana, DasariTomer, AvinashGhosh, PrasenjitMukhopadhyay, Rabindra
When the flow of fluid within a high-pressure line is abruptly halted, pressure pulsations are generated. This phenomenon is known as the water hammer effect. This may lead to significant stress and, in the worst-case scenario, results in various types of failures within the highly pressurized system. Similar issues are observed in diesel high pressure fuel line where pressure is well above 1600 bar. Due to multiple injections on-off events, pressure pulsation gets created inside high pressure fuel lines (HPFL) which leads to problems such as high strain on high pressure fuel lines, mechanical damage, uneven fuel injected quantity, vibration beyond specification limits for rail pressure sensors or in worst case extreme noise. This is due to high pressure pulsation which occurs when fluid/fuel natural frequency resonates with structural HPFL natural frequency. In this work, A comparative FEA analysis is conducted to evaluate strain in two distinct high-pressure fuel lines, with pressure
Bawache, Krushna RameshSethy, Girija Kumari
A significant contributor to particle mass (PM) emissions originating from road transport are particles emitted from brakes, which in Europe are considered in the upcoming Euro 7 emission legislation. UN-GTR (United Nations Global Technical Regulation) no. 24 describes the methodology for measuring brake particle emissions in a test cell setting with a dynamometer, both in terms of PM and PN (particle number). A regulation-compliant test fulfills various quality criteria for different control parameters, which can often be met by applying different control strategies. In this study, we evaluate the effects of implementing different control strategies for torque applied to the brake by the dynamometer, as well as for sampling flow. Additionally, we discuss the cost-saving potential of increasing the automation degree of testing, as well as modifying existing testbeds to accommodate brake emission testing. The torque control strategies applied in this study did not influence PN or PM
Martikainen, SampsaWeidinger, ChristophHuber, Michael Peter
Meeting the stringent emissions norms of CEV stage V for medium BMEP engines, CI engines present significant challenges, particularly concerning cold startability. Low ambient temperatures and pressures intensify the cold start difficulties which are characterized by prolonged cranking, incidences of misfiring, compromised transient response and overall engine performance. This paper highlights the strategies and technologies employed to enhance cold start and transient performance of medium BMEP engines under such demanding environmental conditions. Investigations were conducted up to an altitude of 4500m and ambient temperatures as low as-20°C, utilizing only air heater at intake manifold as the sole cold start aid. This cost effective approach is integrated with an optimized combustion chamber design, along with minimal pilot injection timing and quantity to facilitate smooth ignition and stable combustion during cold start. The paper also explore the techniques to improve the
Saxena, HarshitLokare, PrasadSanthosh, AjithGandhi, NareshShinde, Prashant
Hydrogen is a zero-carbon fuel suitable for the de-carbonization of power generation and the industrial sector. Green hydrogen produced via the electrolysis of water is the most sustainable fuel to achieve a net-zero carbon economy. Oxy-hydrogen (hydrogen and oxygen) generated onsite from the electrolyzer can be fed to engine with the intake air to enhance power and combustion efficiency with near-zero exhaust emissions. In this study, a 15 kVA two-cylinder natural gas spark-ignition generator set was used. The engine was retrofitted to operate on an oxy-hydrogen-air mixture. A maximum of 43% of rated engine load was achieved during the preliminary experiments. GT-Power software was used to calibrate the 1D model using experiment data and generate the burn profile of oxy-hydrogen-air mixture. The calibrated and validated 1D model was used for further predictive simulations. The power limiting factors were identified via simulations for flow and power improvement. The simulations
Marwaha, AksheyTule, ShubhamMishrikotkar, PrasadAghav, Yogesh
The vertical dynamic stiffness and damping of a tyre are critical to ride comfort and overall dynamics, particularly for low-frequency excitations in urban and highway driving. As the tyres are the primary interface between the vehicle and the road, absorbing surface irregularities before the suspension engagement, precise tyre parametrization is essential for accurate ride models. This study investigates an experimental methodology characterizing the vertical dynamic behavior of pneumatic tyres using a Flat Trac test machine. Contrary to the conventional approaches that depend on intricate shaker rigs or frequency dependence function models, the proposed technique uses a realistic force displacement loop-based methodology which is appropriate for ride models. Dynamic stiffness is computed from slope of a linear regression fitted to force and displacements during vertical sinusoidal excitation. Damping is derived from hysteresis energy loss per cycle. The tests were conducted under
Duryodhana, DasariSethumadhavan, ArjunTomer, AvinashGhosh, PrasenjitMukhopadhyay, Rabindra
Side crashes are generally hazardous because there is no room for large deformation to protect an occupant from the crash forces. A crucial point in side impacts is the rapid intrusion of the side structure into the passenger compartment which need sufficient space between occupants and door trim to enable a proper unfolding of the side airbag. This problem can be alleviated by using the rising air pressure inside the door as an additional input for crash sensing. With improvements in the crash sensor technology, pressure sensors that detect pressure changes in door cavities have been developed recently for vehicle crash safety applications. The crash pulses recorded by the acceleration based crash sensors usually exhibit high frequency and noisy responses. The data obtained from the pressure sensors exhibit lower frequency and less noisy responses. Due to its ability to discriminate crash severities and allow the restraint devices to deploy earlier, the pressure sensor technology has
Bhagat, MilindNarale, NaganathMahajan, AshutoshWayal, VirendraJadhav, Swapnil
This study presents a comprehensive 1D simulation approach of an automotive solenoid-based diesel fuel injector and a common rail injection system for a marine engine using Simcenter AMESim. The injector model was developed to analyse the injection rate and total injected fuel at various solenoid actuation durations (1.2 ms and 2.0 ms) and common rail pressures. The experimental results from a well-established research study are used for validating the simulation results of the solenoid-based injector. Overall error in total fuel injected ranges from -6.14 percent to 1.93 percent, while timing errors for the start of injection vary from 1.7° crank angle (CA) to 0.08° CA and the end of injection from 2.8° CA to 0.20° CA at 1200 rpm demonstrating strong agreement at higher rail pressures (above 1000 bar) and solenoid actuation times. Building on this validated injector model, a detailed marine common rail system was developed incorporating key hydraulic components: a check valve to
Bhoware, YashPise, UdaySaha, DiptaGaikwad, Nilesh
The purpose of this research is to examine the fundamental principles of a circular economy (CE) in relation to the automotive industry in India, which plays a vital role in the country's economy. As a result, energy consumption and environmental impacts also pose significant challenges. CE provide a transformative approach through the life cycle of a vehicle, guiding the automotive industry toward a more sustainable transportation system. In order to decarbonize this industry, the global automotive commission recommends that recycled plastic content in vehicles be increased to 20-25% by 2030. This target necessitates the recovery of plastics from end-of-life vehicles, though these materials are rarely integrated into compounds today. The automotive industry's reliance on plastics has grown substantially due to their lightweight properties, which enhance fuel efficiency, reduce CO₂ emissions, and improve versatility and mechanical performance. polypropylene polymer and several other
Kumar, Vijay Bhooshan
The purpose of this document is to present test methods that can be utilized to evaluate the filtration and operating characteristics of filters that will be utilized in a cryogenic system. The methods presented herein are intended to supplement standard filter testing specifications to allow evaluation of filter performance characteristics in areas that could be affected by extreme low temperatures.
A-6C1 Fluids and Contamination Control Committee
In the context of the accelerating urbanization process, the problem of urban traffic congestion has become more severe. Rail transit, with its advantages of high efficiency, convenience, and environmental friendliness, has become a key force in alleviating urban traffic pressure. An in - depth exploration of passengers’ willingness to travel by rail transit is of great significance for optimizing urban traffic planning, improving the service quality of rail transit, and promoting the sustainable development of cities. This article starts from two dimensions: objective factors and passengers’ subjective perceptions, and comprehensively uses a variety of research methods to conduct an in - depth study on passengers’ willingness to travel by rail transit. In terms of objective factors, this article analyzes the differences in subjective perceptions among different passenger groups from the perspectives of gender, age, education level, and occupation. In terms of subjective perceptions
Wang, GangHuang, LeiYang, Yihao
The effective measurement and verification of dimensional stability indicators for large size and highly stable structures in service environments is the key to the development of high-precision spacecraft technology. Spatial carrier speckle interferometry technology has been widely used for high-precision measurements in recent years due to its advantages of fast speed, high accuracy, and simple operation. However, the existing technical research only focuses on the measurement under normal temperature and pressure environments, and there is little research on the application under complex operating conditions in space. There is currently no relevant research on the impact of system ambient vibration and noise on measurement stability disturbances. In response to the above issues, a high-precision deformation measurement system suitable for complex environments of high and low temperatures in a vacuum was designed based on spatial carrier measurement technology. A system measurement
Sun, ZijieTang, XiaojunChen, DongkangkangYang, DeyuYu, WentaoLi, XiaqiaoXin, Liang
To address the escalating traffic demands and tackle the complex mechanical challenges inherent in in-situ tunnel expansion, this study, grounded in the Huangtuling Tunnel project in Zhejiang Province, China, focuses on the stability evolution of surrounding rock and the mechanical characteristics of structures during the in-situ expansion of existing tunnels under weak surrounding rock conditions. By systematically comparing core post-excavation features—such as surrounding rock displacement fields, ground pressure distribution pat-terns, and mechanical responses of support structures—between newly constructed tunnels and in-situ expanded tunnels, the research reveals key mechanical principles governing the construction of large-section tunnels in weak rock formations. Specifically, the findings are as follows: (1) Both newly constructed and in-situ expanded large-section tunnels exhibit significant spatial heterogeneity in surrounding rock deformation. The vault-spandrel zones serve
Zheng, XiaoqingKang, XiaoyueXu, KaiChen, TaoHuo, XinwangChen, Chuan
The presence of time-varying loads on shell structures can result in the generation of undesirable noise in the time domain. This paper presents a time-domain noise control method based on piezoelectric smart shell structures. Firstly, a coupled time-domain finite element/boundary element method (TDFEM/BEM) is used to calculate the sound pressure radiated from shell structures subjected to arbitrary time-varying loads. Then a classical time-domain CGVF algorithm is used to control the vibration and to suppress the sound radiation from structures. Finally, numerical examples demonstrate a 44.2% reduction in the displacement response, a 35.8% decrease in acceleration response, a 36.2% decline in sound pressure of the central node, and a 28.5% decrease in average surface sound pressure. The results show that after CGVF control, the vibration and radiation noise of the plate/shell structure under time domain load are effectively reduced, which is of great significance in engineering
Zheng, HaoWang, HongfuLi, JingjingZhou, QiangSun, YongZhou, LingZhang, HongliangWang, BaichuanHuang, JunsongLiu, XiaorangYin, Guochuan
In this article we will discuss the development and implementation of a computer vision system to be used in decision-making and control of an electro-hydraulic mechanism in order to guarantee correct functioning and efficiency during the logistics project. To achieve this, we have brought together a team of engineering students with knowledge in the area of Artificial Intelligence, Front End and mechanical, electrical and hydraulic devices. The project consists of installing a system on a forklift that moves packaged household appliances that can identify and differentiate the different types of products moved in factories and distribution centers. Therefore, the objective will be to process this identification and control an electro-hydraulic pressure control valve (normally controlled in PWM) so that it releases only the hydraulic pressure configured for each type of packaging/product, and thus correctly squeezing (compressing) the specific volume, without damaging it due to
Furquim, Bruno BuenoPivetta, Italo MeneguelloIbusuki, Ugo
In early of 2023 the European Union began the process of banning the so-called Per- and polyfluoroalkyl substances, with a total elimination forecast for 2035. Currently, the refrigerant gas used by automakers is the R1234yf, a substitute for the R134a as a refrigerant with zero degree of ozone layer destruction, developed to meet the European directive 2006/40/EC that came into force in 2011. It requires all new car platforms for sale on the continent to use a refrigerant in their air-conditioning system with a Global Warming Potential below 150. The alternatives studies for the replacement of R1234yf are R744 (CO2) and R290 (Propane). The first is characterized by being a non-flammable gas and has a working pressure of 6 to 12 times higher than the current one. The second has the characteristic of having working pressure similar to R1234yf, but it is a highly flammable gas. This work focuses on the analysis of the two alternative gases to R1234yf, exploring their characteristics
Ariza, Valquíria RezendeErberelli, Diego PivattoSilva, Pedro Henrique Moraes daMiyauchi, Edison Tsutomu
This study presents three methods for obtaining the latency of an indirect injection Electro-Injector as a function of the applied voltage. This parameter is relevant for the linearization of the injected mass in order to model fuel mass delivery on modern ECUs. For this purpose, the authors built a test bench, with the intent of running analysis on the results of tests of mass differential between injections, circulating current, and mechanical vibration. The authors gathered data over the iterative experiments and correlated the mass differential, vibration data and current measurements. The authors observed that with a reduction of supply voltage at the injector’s pins, a greater injector dead time made itself present displaying a need for a compensation of opening time in function of voltage since the injector’s needle takes a longer amount of time in partially open positions. Modern ECU manufacturers broadly use the data obtained by this type of iterative experiment to accurately
Juliatti, Rafael MotterOliveira, Julia Mathias deMorais Hanriot, Sérgio deSilveira, Hairton Júnior Jose daMoreira, Vinicius Guerra
With the rapid development of the aviation industry, there is an increasing demand for safe apron operations and support capabilities. As a key facility in the apron fuel supply pipeline network, the performance and stability of the fuel hydrant well are crucial. However, the traditional repair and replacement process for fuel hydrant wells faces challenges, including lengthy construction times and significant impacts on airport operations. To address these issues, this article proposes a prefabricated refueling hydrant well technology, aimed at achieving rapid replacement of hydrants under non-stop construction conditions. Through on-site experiments, we have verified the feasibility of this prefabricated fuel hydrant well technology, determined the minimum dismantling boundary, and studied the rapid dismantling process, prefabricated pavement structure and installation process, as well as the application of self-compacting and fast-setting high-strength wellbore filling materials
Ren, YuchengZhao, KunyangChang, LingsuWang, XiangjunHan, TianhuiLi, Zonghe
The control of rainfall runoff drainage in large airports presents significant challenges, particularly in terms of real-time coupling with meteorological warnings. This paper proposes an optimization method for the layout of sponge-like drainage ditches in large airports under BIM-3DGIS coupling. A BIM water supply and drainage model is constructed, with detailed inspections conducted on the functions and connections of the pipeline system in Revit software. The flow velocity and equivalent water supply pressure within the pipelines are analyzed, and collision detection is performed on the components. Based on 3DGIS technology, an optimization model for the layout of sponge-like drainage ditches is established, taking into comprehensive consideration various factors such as airport topography, rainfall characteristics, and surrounding environment. By calculating the water level changes within the infiltration and drainage ditches under different design rainfall scenarios, the storage
Geng, LiangsuiZhao, ZhenyuHu, Jing
In this study, an intelligent monitoring system for electric vehicle seats based on flexible pressure sensor array is proposed. Through the design of multi-layer composite film structure and the collaborative development of STM32 embedded platform, high-precision sensing (error<5%) and rapid response (<200ms) of pressure distribution are realized. The experimental results show that the linearity of the sensor array is ± 1.5% FS in the range of 0-100kpa, and the dynamic response time is 3.6 times higher than that of the traditional sensor; By establishing a three-level adjustment algorithm (fuzzy PID+LSTM prediction+genetic optimization), the seat comfort is improved by 20.5%, and the system energy consumption is reduced by 33.5%. The research provides theoretical and technical support for the transformation of intelligent seats from “passive support” to “active interaction”.
Huang, YifengRong, DaozhiLin, GuoyongHuang, ZhenguiWang, RuliangTao, Chengxi
The study focuses on the management of deep foundation pit excavation, influenced by temporal and spatial factors, in the context of the challenging environmental circumstances posed by the high-water-level silty soft clay along the Yellow River's northern shore, as part of the Jinan urban rail transit initiative. The subsequent inferences have been made: (1) Throughout the digging phase, issues such as excessive digging and delays in installing steel reinforcements occur, while the subterranean diaphragm wall tends to shift significantly inward within the excavation area due to the disparity in pressure between the water and soil inside and outside. (2) During the building phase, managing wall distortion is imperative, and an enhanced preliminary force should be applied to the support's axial component at points of significant deformation, guaranteeing an excess coefficient for both the support rigidity and the continuous subterranean wall rigidity. (3) In the process of diaphragm
Gao, TiangangZhang, XuPan, FuyongZhang, Wenjun
This paper attempts to introduce a unique water transport system by using open-bottomed air tanks in a water transport vehicle and using horizontal buoyancy instead of vertical buoyancy. This study explains how a certain amount of horizontal buoyancy is generated by attaching open-bottomed air vessels to commonly used small watercraft. In contrast to the fact that vehicles generally require a lot of water for all water transport, this new mode of transport can use a minimal amount of water, as appropriate for the weight, through a sufficient literature survey. The proposed water–air–based vehicle integrates open-bottomed air vessels with a hydrofoil system to generate horizontal propulsion. A model analysis is conducted to explain how the horizontal buoyancy force generated by the air vessels is related to the vertical buoyancy force, and their values at different depths are tabulated. The vehicle model can achieve a maximum speed of 1.5 m/s, handling 20–70 kg payload, highlighting
Santhiyagu, Arulanantha Samy
Researchers at the University of California San Diego have developed a soft robotic skin that enables vine robots that are just a few millimeters wide to navigate convoluted paths and fragile environments. To accomplish this, the researchers integrated a very thin layer of actuators made of liquid crystal elastomer at strategic locations in the soft skin. The robot is steered by controlling the pressure inside its body and temperature of the actuators.
This experimental study compared a blend of diesel–DEE (DEE 40% v/v in diesel) with baseline diesel. This experimental study assesses different fuel injection strategies for controlling the in-cylinder charge stratification, such as single, double, and triple injections. The peak in-cylinder pressure under the partially premixed combustion mode was higher than conventional diesel combustion. Higher in-cylinder pressure with increasing dwell time was observed under triple injections. Retarding pilot injections increased the peak in-cylinder pressure. Conventional diesel combustion mode exhibited the highest brake thermal efficiency and lowest emissions with all injection strategies. A longer dwell time of 12° CA showed higher brake thermal efficiency, nitric oxide, and carbon monoxide emissions, whereas hydrocarbon emissions were lower compared to a shorter dwell time of 6° CA. Hydrocarbon and carbon monoxide emissions increased, but nitric oxide and brake thermal efficiency were
Sonawane, UtkarshaAgarwal, Avinash Kumar
With the rapid development of e-commerce, the logistics industry also presents new features such as multi-level, integrated upstream-downstream operations, increasingly perfect service quality and low logistics costs. The exponential growth in online transactions and consumer expectations for faster, more reliable deliveries intensifies the pressure on logistics systems. The last-mile service network refers to the logistics nodes that have direct contact with consumers, and its geographical location and quantity will directly affect the service level, cost and customer service mode of the distribution network. However, with the rapid growth in the number of online shoppers and their imbalance on the Internet, these factors have gradually become an important basis for influencing the layout of terminal outlets. This imbalance, coupled with dynamic urban traffic conditions, renders traditional distribution planning methods inadequate. Therefore, in the e-commerce environment, how to
Tong, TongGu, XuefeiLi, Lingxiao
The knowledge of the brake linings coefficient of friction (BLCF) is crucial for the control of the braking moment in modern vehicles equipped with electric powertrains. In the case of race vehicles equipped with carbon–carbon brakes, the coefficient of friction exhibits great variations as a function of the main influencing factors, namely the pressure, the temperature, and the sliding speed at the pad–disc interface. In this work, a Le Mans Hypercar instrumented with more than 150 sensors was adopted to perform the characterization of the BLCF from racetrack acquisitions. The front and rear left suspensions of the vehicle were instrumented with strain gauge channels and position transducers to acquire the reaction loads at the upright and the orientation of the arms. Then, the geometric matrix method was implemented for calculating the moments at the upright from which the braking torque was derived without the need to know any of the wheel inertia, nor the driveshaft torque. Data
Cortivo, DavideVendramin, MattiaDindo, Luigi
This paper presents an analysis methodology developed to comprehend 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 a simulation methodology to replicate the transient behavior of the dynamic 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 appropriate fidelity to accurately replicate the transient behavior and magnitudes of pressure spikes. This
Memane, NileshKumar, SuneelVeerkar, Vikrant
Tippers transporting loose bulk cargo during prolonged descents are subject to two critical operational challenges: cargo displacement and rear axle lifting. Uncontrolled cargo movement, often involving loose aggregates or soil, arises due to gravitational forces and insufficient restraint systems. This phenomenon can lead to cabin damage, loss of control, and hazardous discharge of materials onto roadways. Simultaneously, load imbalances during descent can cause rear axle lift, increasing stress on the front steering axle, resulting in tire slippage and compromised maneuverability. This study proposes a dynamic control strategy that adjusts the tipper lift angle in real time to align with the descent angle of the road. By synchronizing the trailer bed angle with the slope of the terrain, the system minimizes cargo instability, maintains rear axle contact, and enhances braking performance, including engine and exhaust braking systems. Computational modelling is employed to assess the
Vijeth, AbhishekBhosle, Devidas AshokCherian, RoshniDash, Prasanjita
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 SCR dozers is restrained to the mean injected mass measurement in given operating conditions, since the use of conventional injection analyzers is unfeasible. In the present paper, an innovative injection analyzer is used to measure both the injection rate and the injected mass of each single injection event, enabling a proper dispersion investigation of the analysed low pressure injection 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-to-downstream pressure differential. Further, the injector can inject freely against air
Postrioti, LucioMaka, CristianMartino, Manuel
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, GeethaK, NeelimaSudarmani, RC, VenkataramananSatyam, SatyamNagarajan, Sudarson
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
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, YashNadge, PankajManna, Suvankar
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, ChaoyangZhang, ZhihuaLiu, ZongkuiSui, Jiuling
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, XiaohongYing, RongrongZhou, Lin
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, RenqiangNguyen, Vanliem
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.ShaheerJin, LongYu, XiaoReader, GrahamZheng, Ming
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, YukiMisono, KatsuhiroSuzuki, YoshikatuNaiki, TaketoraWatanabe, ManabuMoriyama, HinataMorii, YouhiTsunoda, AkiraMaruta, Kaoru
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, AlexDubbini, AlbertoRiva, GiorgioCantoni, Carlo
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
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, OmarMenaca, RafaelLiu, XinleiUddeen, KalimTang, QinglongTurner, JamesIm, Hong G.
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 CristinaDe Robbio, RobertaPalomba, Marco
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, SajidAhmad, ZeeshanMahmoudzadeh Andwari, AminKakoee, AlirezaHyvonen, JariMikulski, Maciej
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, PascalGlauner, ManuelDinwoodie, JulesBuchholz, Bert
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, CarloTinchon, AlexisHespel, CamilleDober, GavinFoucher, Fabrice
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.
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.
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. JiniKumar, P. DeepakPanchksharayya, D. V.Kousik Kumaar, R.Praveen, N.
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