bluuebunny/crossref_metadata_2025 huggingface dataset:
Microvascular Reconstruction for Complex Lower-extremity Trauma in Pregnancy
Authors: Mofikoya Bolaji O. , Ofodile Nnamdi Chidozie , Ogedegbe Felix Ehidiamhen , Akinmola Olusola Allen
Published: August 2023

Microvascular reconstruction in pregnancy is rare. We report a case of complex distal lower-extremity trauma in early pregnancy reconstructed with a microvascular free muscle flap. A 30-year-old female with 13 weeks gestation had a crush avulsion of the distal left leg with medial malleolar fracture; she had two sessions of debridement, joint stabilising external fixator frame, and a vaccum assisted closure dressing application. Two weeks later, a right latissimus muscle flap was harvested. Flap was transferred to the debrided leg defect. The thoracodorsal vessels were anastomosed end to end to the anterior tibial artery and the concomitant vein. The flap was immediately revascularised. Continuous post-operative heparin infusion was administered. The muscle was covered with split-thickness skin graft 48 hrs later. Healing and post-operative recovery were uneventful. This report suggests that careful surgical and anesthetic techniques, along with a balanced post-operative anticoagulation protocol, can achieve satisfactory microvascular reconstruction in pregnancy.
General Practitioners’ Knowledge, Attitudes and Practices towards Health Promotion in Morocco
Authors: Mansoury Ouassim , Essoli Samira , Kachkouch Hamza , Mansouri Adil , Adarmouch Latifa , Amine Mohamed , Sebbani Majda
Published: August 2023

Background:

Health promotion (HP) is a part of the general practitioners’ (GPs) competencies defined by the World Organization of Family Doctors. The implementation of HP in their practice is unsatisfactory.

Aims:

The aim of this study was to explore GPs knowledge, attitudes and practices in Morocco about HP at the primary healthcare services.

Methods:

A cross-sectional study was conducted using an online self-administrated questionnaire including, knowledge, attitudes and practices of GPs toward HP. Descriptive and bivariate analyses were conducted.

Results:

Two hundred and forty GPs responded to our questionnaires, the sex ratio was 1.12 with an average age of 40.46 ± 9.05 years. More than half of our participants perceived HP as a concept indistinct from prevention, 70.4% believed that HP refers to the biomedical model. On a Likert scale of 1–5, the level of HP knowledge was 2.71 ± 1.13. The most discussed topics with the population were tobacco, alcohol, overweight and obesity. Statistically significant association was found between the competencies of GPs in lifestyle behaviours and the practice of this competence.

Conclusion:

The knowledge of GPs remains insufficient, and their practices focus more on the areas in which they feel competent, which requires the implementation of specific training for the development of GPs skills in HP.
Knowledge and perception of telerehabilitation in patients with chronic neurological conditions
Authors: Jain Nikhil , Chavhan Dinesh , Dabadghav Rachana , Shyam Ashok , Sancheti Parag
Published: August 2023

BACKGROUND:

Telerehabilitation (TR) delivers rehabilitation across a distance using information and communication technologies. It has several potential advantages over in-person rehabilitation. It can improve patient access to rehabilitation services and reduce monetary, time, and environmental costs associated with travel.

AIM:

The aim of this study was to assess the knowledge and perception of TR in patients with chronic neurological conditions.

SETTING:

It was a community and tertiary care.

DESIGN:

It was a questionnaire-based survey.

SUBJECTS AND METHODS:

A self-made questionnaire was validated and circulated physically and online through Google Forms to the patients with chronic neurological conditions who have undergone TR or at least have some idea about it. One hundred seven patients who fit under the inclusion criteria filled out the form after giving consent. The responses were collected; descriptive data analysis was done; and results were obtained. Descriptive analysis was done by calculating mean and standard deviation.

RESULTS:

Out of 107 participants recruited for the research, 83 (77.6%) were males and 24 (22.4%) were females. Out of these, 51 (47.40%) are aware of TR but have never used it, 43 (40.20%) use it as advised by physiotherapists/doctors, and 13 (12.10%) use it only sometimes. None of them uses it regularly.

CONCLUSION:

From this study, it can be concluded that there is a significant amount of knowledge and perception of TR in chronic neurological patients, required they have at least some idea about TR. It is used most commonly in patients with stroke, followed by traumatic brain injury and spinal cord injury.
Musculoskeletal injuries in salespersons: A survey study
Authors: Phatak Janhavi Vinay , Joseph Sibi Daniel
Published: August 2023

BACKGROUND:

Salespersons job includes prolonged standing and manual handling such as lifting, carrying, and arranging objects, also pushing or pulling heavy objects. Application of force, high repetition, and awkward working posture are the physical risk factors of musculoskeletal injuries and exposure to these leads to a series of disorders.

AIM:

The study aimed to find out the prevalence of musculoskeletal injuries in salespersons.

SETTINGS AND DESIGN:

Stores selling sports products (Decathlon stores), cross-sectional study.

SUBJECTS AND METHODS:

This study was a cross-sectional analysis conducted over 6 months. Ethical clearance was obtained from the institutional ethics committee and the store committee for the study. A total of 100 salespersons working in stores selling sports products were included in the study. The participants were selected based on specific inclusion criteria, which included being between the ages of 18 and 45 years and having a minimum of 1 year of experience working as a salesperson. Demographic data and general characteristics of the participants working as salespersons were obtained, and later the Nordic Musculoskeletal Questionnaire was administered to the participants through online forms. The responses were recorded, and descriptive analysis was done using SPSS software.

RESULTS:

In this study involving 100 participants, it was found that 87% of them experienced musculoskeletal injuries, leading to pain and discomfort. The most common areas affected were the low back (61%), ankles/feet (42%), knees (36%), and neck (19%).

CONCLUSION:

There is a high prevalence of musculoskeletal injuries among salespersons. Low back was the region most affected, followed by ankles/feet, knees, and neck.
Security and Privacy in Fog/Cloud-based IoT Systems for AI and Robotics
Authors: Singh Prabh Deep , Deep Singh Kiran
Published: August 2023

Integration of Internet of Things (IoT) systems based on the fog or the cloud with Artificial Intelligence (AI) and Robotics has prepared the way for breakthrough advancements in a variety of different fields of business. However, these cross-disciplinary technologies present significant difficulties in terms of maintaining confidentiality and safeguarding data. This article digs into the issues of establishing robust security and protecting user privacy in IoT systems that are based in the fog or the cloud and are utilized for AI and robotics applications. This study gives insights into the possible hazards encountered by such interconnected systems by conducting an in-depth review of existing security threats, vulnerabilities, and privacy concerns. In addition, the study investigates cutting-edge security mechanisms, encryption approaches, access control strategies, and privacy-preserving solutions that can be utilized to safeguard data, communications, and user identities. The results of this study highlight the demand for comprehensive security and privacy solutions to support the mainstream deployment of Fog/Cloud-based Internet of Things systems in the field of artificial intelligence and robotics.
IoT Challenges, Solution Framework And Implementation
Authors: Mittal Pooja , Sharma Monika , Nath Thulal Amit
Published: August 2023

The Internet of Things is a vast growing technology that is almost applicable in all fields and has simplified our lives. IOT is being used everywhere these days, including in smart cities, smart environments, security, smart business processes, smart agriculture, healthcare, and many more fields. Being able to cover various fields, is very challenging and presents various problems. This paper highlights IOT components, building blocks, enabling technologies, characteristics, applications, and products, as well as the issues encountered by them and lastly their causes. It brings forward seven steps of proposed solutions for handling and eliminating the problems encountered by almost all IOT devices and applications.  The main aim of this paper is to provide the solution for all the issues which have been talked about for years but could not be able to resolve.
Dried Serum Samples for Antibody Detection in Arthropod-Borne Virus Infections Are an Effective Alternative to Serum Samples
Authors: Würsch Daniela , Rojas-Montes Othon , Maldonado-Rodríguez Angélica , Sevilla-Reyes Edgar , Cevallos Ana María , Sánchez-Burgos Gilma , Chávez-Negrete Adolfo , Lira Rosalía
Published: August 2023

The disease burden of arthropod-borne infections is particularly high in low- and middle-income countries, where the availability of resources for surveillance and testing is limited. The lack of local infrastructure demands that biological samples be sent to central laboratories by refrigerated transport, which increases costs and the risk of sample degradation. Dried blood spot samples are an alternative for ensuring sample integrity during transportation and storage. They can be used for the detection of nucleic acids and proteins, such as antigens or antibodies. Here, we compared anti-chikungunya IgM, anti-dengue IgM, anti-dengue IgG, and anti-Zika IgG detection between paired serum and dried serum samples (DSSs); the agreement between results was found to be 90.6%, 94.1%, 85.9%, and 95.5%, respectively, indicating a strong correlation. Our results suggest that DSSs provide a reliable alternative for detection of specific antibodies in arthropod-borne infections.
Air Path Design, Technical Definition and Pre-Calibration of an Ultra-Lean Hydrogen Engine Based on OD/1D Simulation
Authors: Dubouil Rémi , Perrot Nicolas , Goumy Guillaume , Chesse Pascal
Published: August 2023

Transport sector decarbonization is a key requirement to achieve Green House Gases emissions reduction. Future regulations and the large deployment of Low Emission Zones (LEZ) will lead to deep changes in this sector. The green hydrogen appears as a promising fuel, containing no carbon. H2 Internal combustion engine (H2 ICE) offers the opportunities of quick refueling, known reliability, relative low total cost of ownership. It is based on mature manufacturing processes and tools. Hence this solution can be commercialized in a near future, offering a short term pathway to decarbonization and a H2 market growth accelerator.

However, hydrogen combustion in air generates NOx emissions, which should be reduced close to zero to fulfill future requirements.

The HyMot project gathers seven public and industrial partners to develop an H2 engine for Light Commercial Vehicle (LCV) application offering the same performances as the replaced Diesel Engine. Target is intercity use with access to LEZ. The consortium develop an H2 engine almost from blanksheet which will be integrated in a demonstrator. The minimum air fuel ratio target will be 2.5 on the whole engine map, so that NOx emissions stay at a very low level. This requires a specific air path to reach performance targets, with H2 and vehicle constraints.

This paper presents the 0D/1D model developed to design this new air path, define its architecture and choose the most efficient components. We will present the assumptions, the used methodology and the management of the different actuators. The model was used to build a virtual database to size some mechanical elements and the cooling system, define the valve lift and to supply boundary conditions for the combustion chamber and the after – treatment devices. Both static and transient conditions were studied to give some hints to calibration department in advance.

The authors are aware that a purely simulation-based study has significant limitations when it comes to characterize the behaviour of an internal combustion engine. Further research will involve an experimental validation step for the results presented here as soon as real engine data are available.
Numerical Investigation of the Ignition Delay and Laminar Flame Speed for Pilot-Ignited Dual Fuel Engine Operation with Hydrogen or Methanol
Authors: Parsa Somayeh , Verhelst Sebastian
Published: August 2023

The use of renewable fuels such as hydrogen and methanol in marine engines is a promising way to reduce greenhouse gas emissions from maritime transport. Hydrogen and methanol can be used as the main fuel in dual-fuel engines. However, the co-combustion of hydrogen-diesel and methanol-diesel needs to be carefully studied. In the present work, the ignition delay (ID) and laminar burning velocity (LBV) for pilot-ignited dual fuel engine operation with hydrogen or methanol are studied. A constant volume batch reactor numerical setup is used in the open source Cantera code to calculate the effect of the premixed fuel on the ID of the pilot fuel. Also, Cantera is used to simulate a freely-propagating, adiabatic, 1-D flame to estimate the laminar flame speed of either hydrogen or methanol and how it is affected by the presence of pilot fuel. First, suitable chemical kinetic schemes are selected based on experimental data collected from the literature. Then ID and LBV are estimated for different engine-like operating conditions. The effects of different proportions of hydrogen and methanol, as well as different lambdas, on ID and LBV in the high-pressure regime are considered. It is shown how both the ID of the pilot fuel and the LBV of the premixed fuel is strongly affected by the presence of either premixed fuel or pilot, respectively.
High-Speed 2-D Raman and Rayleigh Imaging of a Hydrogen Jet Issued from a Hollow-Cone Piezo Injector
Authors: Wu Bin , Sharma Priybrat , Yu Tao , Palombi Lucia , Wu Hao , Ben Houidi Moez , Panthi Niraj , Roberts William , Magnotti Gaetano
Published: August 2023

This paper reports high-speed (10 kHz and 100 kHz) 2-D Raman/Rayleigh measurements of a hydrogen (H2) jet issued from a Bosch HDEV4 hollow-cone piezo injector in a high-volume constant pressure vessel. During the experiments, a Pa = 10 bar ambient environment with pure nitrogen (N2) is created in the chamber at T = 298 K, and pure H2 is injected vertically with an injection pressure of Pi = 51 bar. To accommodate the transient nature of the injections, a kHz-rate burst-mode laser system with second harmonic output at λ = 532 nm and high-speed CMOS cameras are employed. By sequentially separating the scattered light using dichroic mirrors and bandpass filters, both elastic Rayleigh (λ = 532 nm) and inelastic N2 (λ = 607 nm) and H2 (λ = 683 nm) Raman signals are recorded on individual cameras. With the help of the wavelet denoising algorithm, the detection limit of 2-D Raman imaging is greatly expanded. The H2 mole fraction distribution is then derived directly from scattering signals at 10 kHz for Raman and 100 kHz for Rayleigh, with a spatial resolution of approximately 200 μm (5.0 lp/mm). The current work successfully demonstrates the feasibility of high-speed 2-D Raman and Rayleigh imaging in gaseous fuel injection and the experimental technique could potentially contribute to the design of next-generation high-pressure, high-flowrate H2 injectors.
MEMS Application to Monitor the In-Cylinder Pressure of a Marine Engine
Authors: Mancaruso Ezio , De Simio Luigi , Iannaccone Sabato , Marchitto Luca , Vaglieco Bianca Maria , Milano Luca , Cameretti Maria Cristina
Published: August 2023

The transport of goods and people by sea, today, must meet the need to reduce the consumption of fuel oil. In addition, it has to ensure operational reliability and vessel availability, to reduce maintenance costs and comply with emission legislation.

To this end, it is necessary to apply a marine engine combustion control system already widely used in engines for land transport. This will allow the ship's engines to operate reliably and in compliance with the best performance for which it was designed. The combustion control could also ensure a more balanced operation of the cylinders and reduce the torsional vibrations of the entire engine, as well as the management of the engine according to the adopted fuel: diesel, dual fuel, methanol, ammonia.

Generally, the control of combustion in engines is carried out through the use of pressure sensors that face directly into the combustion chamber. These are expensive systems and are affected by the severe operating conditions of the marine engine. The present work shows how the use of MEMS (Micro Electro-Mechanical System) represents a valid solution to replace the pressure transducers in the chamber. In particular, two MEMS-type accelerometers were used on a single-cylinder research engine with a displacement of 4.2 l for naval applications, fueled by diesel.

A comparative analysis of MEMS sensors with the pressure signal detected in the combustion chamber was conducted. Excellent correspondences were highlighted regarding the moments of closure of the exhaust and intake valves, the instant of start of injection and the instant of start of combustion. The results are encouraging for the use of low-cost and easy-to-apply MEMS sensors (they can be installed outside the engine and there is no need to create specific accesses to the combustion chamber) for effective combustion control of marine engines.
Real Time Modelling of Automotive Electric Drives for Hardware-in-the-Loop Applications
Authors: Poletto Paolo , Angiolini Andrea , Boccardo Giulio , Graziano Eduardo , Vaschetto Silvio , Demelas Roberto
Published: August 2023

The current electrification trend involving hybrid and electric vehicles requires accurate tools to evaluate performance and reliability of electric powertrains’ control systems. Thanks to Hardware in the Loop (HiL) technique, verification, validation and virtual calibration of Electronic Control Systems can be performed without physical plants, addressing the need of frontloading, cost and time reduction of new vehicles control systems development. However, HiL applications with power electronics controllers brings several concerns due to the extremely low timestep needed for accurate simulation of electromagnetic phenomena, making FPGA-based simulation the only option. Moreover, thermal aspects of electric motors are very important from the control perspective as complex thermal management control strategies are implemented to improve the efficiency and to prevent overheating that can cause permanent damage to the electrical machine.

The aim of this work was to develop tools and methodologies for hybrid and electric powertrain control development and testing. In this paper a methodology for the parametrization, deployment and integration of a Permanent Magnet Synchronous Motor (PMSM) FPGA model equipped on the Fiat 500e, will be presented.

The original FPGA motor model, included in the dSPACE XSG Electric library, was modified to consider iron losses and a methodology to parametrize such models using Finite Elements Method (FEM) simulation results was developed. Moreover, a Real-Time thermal model of the electric motor was developed in GT-SUITE and executed on a dSPACE SCALEXIO Real-Time Processor in co-simulation with the electromagnetic model running on a DS6602 FPGA Board. The co-simulation accounts for the temperature dependency of the winding resistance, improving estimation accuracy of powertrain performances and enabling validation of thermal management control strategies.

The developed plant model was validated offline and online on a HiL machine coupled with the real Motor Control Unit (MCU) with respect to experimental data in real driving conditions.
Meta-Model Optimization of Dual-Fuel Engine Performance and Emissions Using Emulsified Diesel with Varying Water Percentages and Injection Timing
Authors: Sehili Youcef , Loubar Khaled , Tarabet Lyes , Mahfoudh Cerdoun , Lacroix Clément
Published: August 2023

As emission restrictions become more stringent and conventional fuel supplies become more limited, dual-fuel engines are emerging as a promising solution that offers both environmental and economic benefits. However, the performance of these engines is often hampered by the issue of knocking, which can negatively impact their overall operation, and also by the increase in NOx emissions at high load. This work investigates the use of pilot injection properties by combining the use of emulsified diesel of different water percentages with injection timing to reduce both knock intensity and NOx emission rate. Specifically, a dual fuel operation case at full load with high enrichment of the primary fuel (natural gas) with hydrogen is considered in order to create conditions for high knocking and high NOx emission rates. The online optimization principle is used for the creation of the meta-model, utilizing the Radial Basis Functions technique (RBF), and the search for the optimum in parallel using the Non-Dominated Sorting Genetic Algorithm (NSGA-II) to handle two objective functions: the minimization of the knock intensity and NOx emissions, and the maximization of the engine thermal efficiency, based on two decision variables: the volume percentage of water in the emulsified diesel (0-30%) and the injection time of this pilot fuel (5-30° CA BTDC). The evaluation of the cases is provided by a CFD calculation model (Converge©) after validation by experimental results. The results indicate that the amount of water contained in the diesel and the injection time have a significant influence on the knock intensity (a decrease of 74%) and the rate of pollutant emissions (a decrease of 61%). The Pareto front summarizes the non-dominated cases according to the two objective functions and indicates that increasing the percentage of water and delaying the pilot injection decrease both the intensity of the knocking and the NOx emissions but penalizes the thermal efficiency of the engine. Therefore, choosing the optimums is crucial in achieving a compromise between the two objective functions.
Numerical Investigation on the Cause-and-Effect Chain for Cycle-to-Cycle Variation of Direct-Injection Spark-Ignition Engine
Authors: Feng Ye , Grill Michael , Kulzer Andre
Published: August 2023

Due to increasingly strict emission regulations, lean combustion concept has become an essential direction of internal combustion engine development to reduce engine emissions. However, lean combustion will lead high combustion instability and unpredictive engine emissions. The combustion instability is represented as the high cycle-to-cycle variation. Therefore, understanding the mechanism of cycle-to-cycle variation is crucial for the internal combustion engine design. This paper investigates the cause-and-effect chain of cycle-to-cycle variation of spark ignition engines using 3D CFD simulations with CONVERGE v3.0. The cyclic variations were simulated through Large Eddy Simulations, and the simulations based on Reynolds-averaged Navier–Stokes were used as supplements. The analysis focuses on two key factors that determine the combustion process: the turbulent intensity and the homogeneity of the air/fuel mixture. It is found that the turbulent intensity varies in combustion phase, and the reasons can be traced back to the tumble variation in the intake phase. The homogeneity of the air/fuel mixture will worsen with higher air-to-fuel equivalence ratio (lambda), which also leads to increased fluctuations in homogeneity. Furthermore, the correlation between homogeneity and tumble intensity enhances with higher lambda, e.g., the correlation coefficient increases from 0.13 to 0.67 as the lambda increases from 0.79 to 1.5. Additionally, the illustrated differences in the flame kernel development between cycles indicated that the local flow conditions play an essential role in the propagation of flame kernel. For example, as the flame kernel is trapped between the electrodes of the spark plug, higher local velocity will blow it across electrodes in a shorter time. Finally, despite the random variations in the flow conditions near the spark plug, an approach was developed to predict the range of local value variations based on the global values. It is significant for the further 0D/1D modeling of cycle-to-cycle variation.
A Comparison of Methanol, Methane and Hydrogen Fuels for SI Engines: Performance and Pollutant Emissions
Authors: Catapano Francesco , Di Iorio Silvana , Magno Agnese , Sementa Paolo , Vaglieco Bianca Maria
Published: August 2023

The urban mobility electrification has been proposed as the main solution to the vehicle emission issues in the next years. However, internal combustion engines have still great potential to decarbonize the transport sector through the use of low/zero-carbon fuels. Alcohols such us methanol, have long been considered attractive alternative fuels for spark ignition engines. They have properties similar to those of gasoline, are easy to transport and store. Recently, great attention has been devoted to gaseous fuels that can be used in existing engine after minor modification allowing to drastically reduce the pollutant emissions.

In this regard, this study tries to provide an overview on the use of alternative fuels, both liquid and gaseous in spark ignition engines, highlighting the benefits as well as the criticalities.

The investigation was carried out on a small displacement spark ignition engine capable to operate both in port fuel and direct injection mode. Engine was fueled with gasoline and methanol in port mode to exploit the advantages of this technology for liquid fuels. Gaseous fuels were injected directly in the chamber to prevent the drawbacks of power loss and abnormal combustion. Tests were performed at different operating conditions typical of urban and extra-urban patterns. Combustion behavior of the tested fuels was analyzed through indicated data. Gaseous fuels were measured at raw exhaust. Particles were characterized in terms of number and size at diluted exhaust.

In general, it was found out a benefit in terms of pollutant emissions with alternative fuels compared to gasoline. The interesting result regards the particle emissions that depend on the combination of the fuel characteristics and the operating conditions. In particular, at some test points, hydrogen shows high particle emissions with values comparable to those of other tested fuels highlighting the contribution of lubricating oil that plays a more significant role when low/zero carbon gaseous fuels are used.
Effect of Intake Conditions (Temperature, Pressure and EGR) on the Operation of a Dual-Fuel Marine Engine with Methanol
Authors: Dierickx Jeroen , Dejaegere Quinten , Van Gijzeghem Andreas , Devos Stan , De Cock Berten , Verhelst Sebastian
Published: August 2023

In the upcoming decade sustainable powertrain technologies will seek for market entrance in the transport sector. One promising solution is the utilization of dual-fuel engines using renewable methanol ignited by a pilot diesel fuel. This approach allows the displacement of a significant portion of fossil diesel, thereby reducing greenhouse gas emissions. Additionally, this technology is, next to newbuilds, suited for retrofitting existing engines, while maintaining high efficiencies and lowering engine-out emissions. Various researchers have experimentally tested the effects of replacing diesel by methanol and have reported different boundaries for substituting diesel by methanol, including misfire, partial burn, knock and pre-ignition. However, little research has been conducted to explore ways to extend these substitution limits. Therefore, this study aims to investigate the effects of intake conditions, such as intake air temperature and pressure, and exhaust gas recirculation (EGR), on these limits, and, moreover, on several other engine performance parameters. It was found that higher intake air temperatures can extend misfire limits slightly, and with a trade-off as the possibility for pre-ignition increases. However, the gains in maximum substitution of diesel by methanol were minimal compared to the effort required to install a temperature control system. A reduction in intake air pressure was tested to mitigate knock but failed to do so, while EGR was able to increase the substitution limit. Brake thermal efficiency increased at high substitution limits with higher intake air temperature, but decreased with lower intake air pressure and with EGR. NOx emissions increased with higher intake air temperature and pressure, but decreased with EGR.
Evaluation of Neat Methanol as Fuel for a Light-Duty Compression Ignition Engine
Authors: Garcia Antonio , Monsalve-Serrano Javier , Guzmán Mendoza María , Gaillard Patrick , Durrett Russell , Vassallo Alberto , Pesce Francesco
Published: August 2023

Methanol is currently being evaluated as a promising alternative fuel for internal combustion engines, due to being attainable by carbon neutral or negative pathways (renewable energy and carbon capture technology). The low ignitability of methanol has made it attractive mostly as a fuel for spark ignition engines, however the low sooting properties of the fuel could potentially reduce the NOx-soot tradeoff present in compression ignition engines. In this work, using a 4-cylinder engine with compression ratio modified from 16:1 to 19:1, methanol combustion is evaluated under five operating conditions in terms of fuel consumption, criteria pollutants, CO2 emissions and engine efficiency in addition to the qualitative assessment of the combustion stability. It was found that combustion is stable at medium to high loads, with medium load NOx emissions levels at least 30% lower than the original diesel engine and comparable emissions at maximum load conditions. The measured soot showed negligible levels; however, HC and CO emissions were exceedingly high. In particular, the lowest load condition had HC and CO values that surpassed 10 g/kWh.
Numerical Investigation of Ammonia-Diesel Fuelled Engine Operated in RCCI Mode
Authors: Fakhari Amir Hossein , Gharehghani Ayat , Salahi Mohammad Mahdi , Mahmoudzadeh Andwari Amin , Mikulski Maciej , Hunicz Jacek , Könnö Juho
Published: August 2023

Ammonia, which is one of the most produced inorganic chemicals worldwide, has gained significant attention in recent years as a carbon-free fuel due to its significant energy density in maritime and power plant applications. This fuel offers several advantages including low production costs and being safe for storage and transport. Reactivity controlled compression ignition (RCCI) combustion mode is considered as a promising strategy reducing the level of nitrogen oxides (NOx) emissions and particulate matters (PM) in internal combustion engines (ICEs) due to the lower combustion temperatures and charge homogeneity. Ammonia-based RCCI combustion strategy can offer a simultaneous reduction of CO2 and NOx. In this study, a RCCI engine fuelled by ammonia and diesel is numerically simulated considering chemical reactions kinetics mechanism of the combustion. After validating the simulation results with literature experimental data, the effect of engine operational parameters such as the initial charge temperature together with injection timing on the engine operational characteristic including in-cylinder pressure, heat release rate (HRR), indicated mean effective pressure (IMEP) and emission levels are investigated and discussed accordingly. The results indicated that advancing the start of injection (SOI) timing from 20 to 100 CAD bTDC, increased the NOx emissions concentration at the initial intake charge temperatures of 460 and 480 K. Higher initial intake charge temperature increased the level of NOx emissions while advancing SOI timing from 20 to 100 CAD bTDC did not disturb the level of CO emission significantly.
Assessment of Dilution Options on a Hydrogen Internal Combustion Engine
Authors: Rouleau Loic , Nowak Ludovic , Duffour Florence , Walter Bruno
Published: August 2023

The hydrogen internal combustion engine is a promising alternative to fossil fuel-based engines, which, in a short time, can reduce the carbon footprint of the ground transport sector. However, the high heat release rates associated with hydrogen combustion results in higher NOx emissions. The NOx production can be mitigated by diluting the in-cylinder mixture with air, Exhaust Gas Recirculation (EGR) or water injected in the intake manifold. This study aims at assessing these dilution options on the emissions, efficiency, combustion performance and boosting effort. These dilution modes are, at first, compared on a single cylinder engine (SCE) with direct injection of hydrogen in steady state conditions. Air and EGR dilutions are then evaluated on a corresponding 4-cylinder engine by 0D simulation on a complete map under NOx emission constraint.

On the SCE at 3000rpm and 10.7bar IMEP, air and EGR dilutions allow a high dilution rate, leading to a significant NOx reduction: from 2.8g/kWh to less than 0.05g/kWh. The indicated efficiency goes through a maximum of about 45.5% with NOx emissions around 0.4g/kWh without affecting the lubricant consumption, calculated from carbon-bearing gas emissions. The water injection doesn’t affect the efficiency but reduces NOx emissions moderately without inducing excessive lubricant consumption. For the three dilution options, a common guide curve of NOx emissions versus a thermal dilution rate, based on the fuel chemical energy, diluent heat capacity and water vaporization latent heat, is presented. The best indicated efficiency for a tolerable NOx level of 0.4g/kWh is achieved for lambda of 2.4 with air dilution path and EGR rate of 10% at lambda of 2. After these dilution tests involving hydrogen and possibly high content of water in the chamber, only a thin layer of corrosion is observed on the iron cast liner without any structural or mechanical damage. The 0D simulation shows the interesting combination of air and EGR dilution allowing higher load under NOx emission constraint. EGR gases containing water with high heat capacity allows to reduce the quantity of diluent at high load, therefore the filling work and turbocharger effort.
Conversion of a Small Size Passenger Car to Hydrogen Fueling: 0D/1D Simulation of Port- vs Direct-Injection and Boosting Requirements
Authors: Irimescu Adrian , Merola Simona , Vaglieco Bianca Maria , Zollo Vasco , De Marinis Raffaele
Published: August 2023

Hydrogen is an energy vector with low environmental impact and will play a significant role in the future of transportation. Converting a spark ignition (SI) engine powered vehicle to H2 fueling has several challenges, but was overall found to be feasible with contained cost. Fuel delivery directly to the cylinder features numerous advantages and can successfully mitigate backfire, a major issue for H2 SI engines. Within this context, the present work investigated the specific fuel system requirements in port- (PFI) and direct-injection (DI) configurations. A 0D/1D model was used to simulate engine operating characteristics in several working conditions. As expected, the model predicted significant improvement of volumetric efficiency for DI compared to the PFI configuration. Boosting requirements were predicted to be at levels quite close to those for gasoline fueling. Apart from tougher requirements with respect to the fact that the injector would have to withstand much higher pressure and temperature, the DI solution would also need to feature higher flow rate. Increased injection pressure was another requirement that was identified as essential for ensuring correct fuel delivery during the compression stroke. The contradicting effects of injection rate and required pressure were investigated in two different hypotheses: low pressure DI (LPDI) and high pressure DI (HPDI).
SprayLet: One-Dimensional Interactive Cross-Sectionally Averaged Spray Model
Authors: Kurapati Vinaykumar Reddy , Anders Borg , Seidel Lars , Mauss Fabian
Published: August 2023

Spray modeling is among the main aspects of mixture formation and combustion in internal combustion engines. It plays a major role in pollutant formation and energy efficiency although adequate modeling is still under development. Strong grid dependence is observed in the droplet-based stochastic spray model commonly used. As an alternative, an interactive model called 'SprayLet' is being developed for spray simulations based on one-dimensional integrated equations for the gas and liquid phases, resulting from cross-sectionally averaging of multi-dimensional transport equations to improve statistical convergence. The formulated one-dimensional cross-section averaged system is solved independently of the CFD program to provide source terms for mass, momentum and heat transfer between the gas and liquid phases. The transport processes take place in a given spray cone where the nozzle exit is automatically resolved. In the 1D program, the conservation equations are for droplet diameter, droplet temperature, as well as for continuity and momentum of the liquid and the gaseous phase are solved. The source terms between the phases are conservatively embedded into the spray region of the CFD program. In CFD program, the transport equations are solved for gas phase only. The SprayLet model is validated using standard Sandia sprays by comparing penetration lengths and fuel mixture fractions with experimental data.
Investigation of Liquid Lignin-Methanol Blends under Realistic Two-Stroke Marine Engines Conditions
Authors: Lazzaro Maurizio , Sementa Paolo , Catapano Francesco , Tornatore Cinzia , Iannuzzi Stefano , Boot Michael , Kouris Panos
Published: August 2023

With a view to reducing the environmental impact of fossil fuels, advanced lignin-based biofuels could provide a valuable contribute, since lignin is the most abundant biopolymer on earth after cellulose. However, its thermophysical properties would hamper its use as a pure fuel. In this work we investigated the combustion behavior of sprays of a liquid lignin-methanol blend and evaluated its potential as a low-carbon marine fuel for large two-stroke engines. To this end, an experimental campaign was conducted in an optically accessible combustion chamber whose main dimensions correspond to those of a single cylinder for large two-stroke engines. The chamber is provided with optical accesses for optical diagnostics of the combustion process. The combustion of the mixture was ignited using a diesel pilot jet as the ignition source. Two marine injectors are mounted in the chamber, namely “main” and “pilot” injectors. The tests were performed in environmental conditions around 40 bar and 500°C. The lignin-methanol blend was injected at pressure of 500 and 700 bar, whilst the injection pressure of the pilot diesel was kept at 500 bar. Two different relative orientations of the main and pilot sprays were investigated. The results showed that this type of fuel is suitable for durability trials for the assessment of its final use in a marine internal combustion engine.
ɸ-Sensitivity Evaluation of n-Butanol and Iso-Butanol Blends with Surrogate Gasoline
Authors: Alemahdi Nika , Garcia Antonio , Tuner Martin
Published: August 2023

Using renewable fuels is a reliable approach for decarbonization of combustion engines. iso-Butanol and n-butanol are known as longer chain alcohols and have the potential of being used as gasoline substitute or a renewable fraction of gasoline. The combustion behavior of renewable fuels in modern combustion engines and advanced combustion concepts is not well understood yet. Low-temperature combustion (LTC) is a concept that is a basis for some of the low emissions-high efficiency combustion technologies. Fuel ɸ-sensitivity is known as a key factor to be considered for tailoring fuels for these engines. The Lund ɸ-sensitivity method is an empirical test method for evaluation of the ɸ-sensitivity of liquid fuels and evaluate fuel behavior in thermal. iso-Butanol and n-butanol are two alcohols which like other alcohol exhibit nonlinear behavior when blended with (surrogate) gasoline in terms of RON and MON. In this study, first the Lund ɸ-sensitivity numbers of iso-butanol and n-butanol at CA50≈3°CA after TDC is measured. CA50 is the rank angle degree at which 50% of total accumulated heat is released. Then, the Lund ɸ-sensitivity number of iso-butanol at two later combustion phasing of CA50≈8 & 6 °CA after TDC is evaluated. Finally, the Lund ɸ-sensitivity number of volumetric blends of iso-butanol and surrogate gasoline (RON≈87) were measured. The results show the ɸ-sensitivity of iso-butanol is lower than n-butanol which means the combustion behavior of iso-butanol is less sensitive to thermal and fuel stratification. The nonlinear behavior of Lund ɸ-sensitivity number of iso-butanol blends with surrogate gasoline is observed. As expected, the later combustion phasing lowers the Lund ɸ-sensitivity number of the tested fuel and increases the experimental range successfully.
Electrofuel Concept of Diesel and Oxygenate Fuels Reduces Engine-Out Emissions
Authors: Aakko-Saksa Paivi , Järvinen Anssi , Karppanen Mikko , Koponen Paivi , Piimäkorpi Pekka , Lehtonen Juha , Harni Sami , Aurela Minna , Timonen Hilkka , Marjanen Petteri , Markkula Lassi , Rönkkö Topi , Hoivala Jussi
Published: August 2023

Electrofuels produced from renewable hydrogen (H2) and captured carbon dioxide (CO2) can be sustainable and carbon-neutral. Paraffinic electrodiesel (e-diesel) can be produced via Fischer-Tropsch synthesis with fuel properties resembling hydrotreated vegetable oils. Electrofuels can be also oxygenated compounds, such as oxymethylene dimethyl ethers (OMEn), having different chain lengths. We studied emissions using paraffinic diesel mimicking e-diesel and its blend with 10% of OME3-5, which has diesel-type fuel properties, in comparison with normal EN590 diesel fuel. An intensive measurement campaign was performed with a modern diesel engine without exhaust aftertreatment to study the effect of fuel on the engine-out emissions. Measurements with the RMC-C1 cycle included detailed characterization of gaseous, particle and polyaromatic hydrocarbon (PAH) emissions having adverse effects on health and the environment. In these tests without a diesel particulate filter, the fuel containing the OME3-5 component reduced the black carbon (BC) emissions substantially in comparison with EN590. PM and PAH emissions, as well as the number of non-volatile particle numbers (nvPN), were lower for paraffinic fuel than for the EN590 fuel, and particularly for the OME3-5 blend. As regards gaseous emissions, paraffinic fuel showed lower engine-out NOx emissions than the EN590 fuel, however, OME3-5 oxygenate did not further increase this NOx reduction. Higher formaldehyde concentration in the exhaust was found for OME3-5 containing fuel than for the hydrocarbon-only fuels, which can be tackled with an inexpensive oxidation catalyst. In summary, e-diesel type paraffinic fuel reduced the engine-out exhaust emissions from a modern diesel engine substantially, and OME3-5 addition further reduced the most harmful emission species even at a 10% blending level.
Automated Kinetic Mechanism Evaluation for e-Fuels Using SciExpeM: The Case of Oxymethylene Ethers
Authors: Dinelli Timoteo , Pratali Maffei Luna , Pegurri Alessandro , Puri Amedeo , Stagni Alessandro , Faravelli Tiziano
Published: August 2023

In the rapidly changing scenario of the energy transition, data-driven tools for kinetic mechanism development and testing can greatly support the evaluation of the combustion properties of new potential e-fuels. Despite the effectiveness of kinetic mechanism generation and optimization procedures and the increased availability of experimental data, integrated methodologies combining data analysis, kinetic simulations, chemical lumping, and kinetic mechanism optimization are still lacking. This paper presents an integrated workflow that combines recently developed automated tools for kinetic mechanism development and testing, from data collection to kinetic model reduction and optimization. The proposed methodology is applied to build a consistent, efficient, and well-performing kinetic mechanism for the combustion of oxymethylene ethers (OMEs), which are promising synthetic e-fuels for transportation. In fact, OMEs are easily mixed with conventional fuels and share similar ignition propensity, and are therefore potential drop-in fuels. Additionally, their oxygenated nature significantly reduces soot emissions. The proposed workflow extends our recently developed kinetic mechanism for OME1 (dimethoxymethane – DMM) to OME2-4: the model is derived from state-of-the-art detailed literature mechanisms, updated according to a reaction class-based approach, and simplified according to chemical lumping. Then, the model is reduced to two different skeletal versions using DRGEP method. An extensive database of ~80 datasets for kinetic mechanism testing is collected, covering different reactor types and experimental conditions. The selected datasets are uploaded to SciExpeM, a recently developed data ecosystem that allows automated kinetic mechanism performance evaluation through a multi-index approach. The performance obtained from SciExpeM shows that the lumped mechanism reproduces well the selected experimental data, and both skeletal mechanisms, well-suited to CFD and engine simulations, show equally good performance. Some minor model deficiencies identified for OME2 and OME3 are finally recovered via data-driven kinetic modeling optimization, which relies on the same multi-index approach adopted in SciExpeM for the kinetic model evaluation.
Efficiency Optimized Engine Operation with CO 2 Neutral Fuels through Thermodynamic Loss Calculation and Model-Based Fuel Detection
Authors: Demel Philipp , Knost Friedemar , Obée Alexander , Beidl Christian
Published: August 2023

Global efforts to reduce anthropogenic carbon dioxide (CO2) emissions require innovative measures in the field of vehicle drives to present solutions in all areas of the transportation sector in the future. Synthetic fuels, that can be used in conventional combustion engines, show promising potentials. An increasing amount of synthetic fuels will be found in the off-highway sector, which is characterized by a high power and work density. The properties of synthetic fuels can differ depending on their chemical structure. In particular, the calorific value (LHV) and the stoichiometric air-fuel-ratio (AFRst) have a direct influence on the performance and emission characteristics of an engine. In addition to providing optimal fuel-specific engine operation, fuel detection can ensure that the engine is only operated with regenerative energy carriers in future. In this paper, the methodical approach for optimizing fuel-specific engine operation on the basis of thermodynamic loss calculation and model-based fuel detection is presented using the example of the synthetic fuel oxymethylene ether (OME). In this context, quantities of the engine control unit (ECU) represent the input values of the fuel detection system. Based on this, neural networks are built to detect the regenerative share in the fuel. By calculating the thermodynamic losses, the fuel-specific losses can be quantified to derive optimization potentials. These are evaluated using steady-state operating points and cycles. The combination of fuel detection, loss quantification and optimization enables the flex-fuel operation of series engines for an optimal use of CO2-neutral fuels.