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A new phased array of microphones, suitable for the harsh environment of a rocket launch, was built and tested during a static firing of an RS-25 engine. It uses 70 piezo-resistive, dynamic pressure sensors, optimally distributed on a 10.5-ft diameter open frame dome structure and has a 200-ft long cable bundle to carry the signals to a weather-protected cabinet containing the data systems. The test stand was imaged using an infra-red camera and a visible wavelength camera, and the beamformed noise maps were superimposed on the photographs. The first-time data from a full-scale engine test stand showed that the plume deflector at the bottom of the engine was the primary noise source. The openings of the test stand around the nozzle exit were also found to be noise sources particularly at higher frequencies. The final goal is to utilize the array during NASA's Artemis-II launch at Kennedy Space Center. [ABSTRACT FROM AUTHOR]

In this study, we deal with the production and utilization of waste-cooking palm biodiesel (WCB) and. evaluated the influence of the addition of titanium dioxide (TiO 2) nanoparticles in hydrogen-enriched single-cylinder CRDI diesel engine. XRD, SEM, and EDX decide the structure and morphology of TiO 2 nanoparticles. The TiO 2 nanoparticles were dispersed in the tested fuels at a dosage of 50–75 ppm with the aid of ultra-sonication. Based on the oxidation stability study, the B20 + 75 ppm (TiO 2) fuel blend is the pilot fuel for the engine test. Further, the engine is enriched with a hydrogen (H 2) flow of 10 lpm. Results revealed that the performance parameters were improved with the addition of H 2 enrichment and TiO 2 nanoparticles compared to D. The brake thermal efficiency of the engine was improved by 8.21%. In comparison, brake-specific fuel consumption decreased by 42.86%. Furthermore, adding nanoparticles also reduced CO and HC emissions by 74% and 27.27%, respectively, whereas the NO x emission was slightly increased. Thus, the findings demonstrated that hydrogen-enriched nanoparticles added to biodiesel might be considered a substitute for fossil fuels and report a positive impact on diesel engine performance without requiring significant modifications. • Waste cooking palm oil biodiesel, H 2 , and TiO 2 nanoparticles are used to run engine. • The mass flow rate of hydrogen is kept constant at 10 lpm. • The tested fuels contained 75 ppm of TiO 2 nanoparticles. • BTE has improve by 8.21% over neat diesel. • CO and HC decreased by 74%, and 27.27%, respectively, with an increase in NO x. [ABSTRACT FROM AUTHOR]

For a long period of time, vegetable oil cannot be used directly in a direct injection diesel engine. The tolerance tests may indicate significant problems. The outcome of Injection Pressures (IP) on the performance and emissions of a diesel engine powered by waste cooking oil biodiesel were explored in this study. It is investigated and standard diesel results are compared to the performance characteristics and emission studies of a single cylinder, four-stroke, direct-injection diesel engine fueled with used cooking oil in 20% (on a mass basis) blends. This study established the appropriateness of using cooking oil. The experiment consisted of running at a constant speed of 1500 rpm and then loaded gradually. The tests were conducted at 5 different loading are 0%, 25%, 50%, 75%, and 100% of the load in kW, with compression ratios of 17.5:1. The result of adjusting the injection pressure to 185-235 bars with a gap of 25 bars, with the original IP set at 210 bar. Fuel injection pressure is critical in improving engine performance and emission characteristics. The diesel engine ran on Waste Cooking Oil (WCO) at various injection pressures, including 185 bars, 210 bars, and 235 bars. The engine tests were carried out to examine how a diesel engine operating on a WCO20 biodiesel blend performed and produced emissions at varied injection pressures. Except for NOx, biodiesel blends at 235 bars injection pressure performed better and had lower emissions than those at 185 bars injection pressure. Without any modifications, the optimal fuel blend can be considered for a compression ignition engine. [ABSTRACT FROM AUTHOR]

The present study utilizes dual biodiesel-alcohol blends to evaluate the engine performance. Five test fuels were prepared on a volume basis with different constituting percentages, each consisting of 70 % pure diesel (D70), a binary blend of biodiesel: B1 (WCO30), a ternary blend of biodiesel: B2 (WCO15 and WCCO15) and three quaternary blends: B3 (WCO10, WCCO15, Bu5), B4 (WCO15, WCCO10, Bu5) and B5 (WCO10, WCCO10, Bu10). The biodiesel is made from used cooking oil. The effects of each blend on engine performance were examined by performing the engine test on a single-cylinder, four-stroke, water-cooled Kirloskar compression ignition (CI) engine at various engine speeds and loads. The indicated power (IP), brake power (BP), friction power (FP), fuel consumption (FC), and mechanical efficiency (%) were evaluated, and the experimental results show that the performance is best for B3 when run with 75 % of the maximum load capacity of the engine. The study thus justifies that to lower the density and viscosity of biodiesel fuel, adding alcohol can be acknowledged as a valuable application to boost the engine's brake thermal efficiency (BTE). This also lowers the emissions of oxides of nitrogen (NOx), carbon monoxide (CO), and hydrocarbons (HC). [ABSTRACT FROM AUTHOR]

The United Nations Sustainable Development Goals (SDGs) are imperative from the point of view of protecting the environment by employing sustainable options. Considerable research has been carried out in the transportation sector to meet this objective. Here, the influence is assessed of epoxidised gingelly oil methyl ester biolubricant with alumina (Al2O3) nanoparticles on the performance and emissions of a single cylinder 0.66-L capacity direct injection compression ignition engine driven by gingelly B20 biodiesel. Engine tests are carried out with gingelly B20 biodiesel as a fuel, and gingelly methyl ester (B100), epoxidised gingelly methyl ester (B100E), and epoxidised gingelly methyl ester (B100E) mixed with 0.5%, 1.0%, and 1.5% w/w alumina (Al2O3) nanoparticles as the lubricant combinations. The results are compared with baseline B20 biodiesel fuel-mineral lubricant operation. The findings indicate that brake thermal efficiency increases by 8.64% for epoxidised gingelly methyl ester (B100E) with 1.0% w/w alumina (Al2O3) nanoparticle biolubricant in comparison to baseline operation. Considerable reductions in emissions are detected; specifically, reductions of 52.4%, 22.0%, 20.0%, and 34.9%, respectively, are observed for CO, NOx, and HC concentrations and smoke opacity for the abovementioned combination as compared to baseline operation. The present work suggests that further research is merited on green fuel-green lubricant combinations. The findings of this study address the United Nations Sustainable Development Goals (SDGs) 7 and 13. [ABSTRACT FROM AUTHOR]

For NOx removal from diesel exhaust, the selective catalytic reduction (SCR) is the most common abatement technology. However, low engine load scenarios such as city driving and cold start phases demand efficient NOx reduction clearly below 200 °C, which is difficult to achieve with SCR. Hence, this work investigates the potential of the low-temperature NOx reduction with H2 in diesel exhaust. A monolithic Pt/WOx/ZrO2 catalyst, recently reported as highly active, was evaluated in synthetic and real diesel exhaust. The monolith demonstrated high deNOx activity between 130 and 215 °C in the synthetic exhaust including peak conversion of 90% with N2 selectivity up to 85%. CO/HC components were shown to inhibit the H2-deNOx conversion thus requiring a pre-oxidation catalyst in practice. Furthermore, studies performed in an optical reactor indicated strong heat evolution along the monolith. As a result, the reaction kinetics was accelerated with an enhanced consumption of H2 limiting the H2-deNOx efficiency above 200 °C. Stationary tests in diesel engine exhaust substantiated the low-temperature H2-deNOx performance of the monolith including NOx conversions up to 80% at temperatures as low as 135 °C. [ABSTRACT FROM AUTHOR]

An electrically heated mixer (EHM™) has been developed. It enables injecting urea-water solution in low temperature Diesel exhaust operations, such as in low-load cycles, real-driving-emissions (RDE), stop-and-go, city driving and local delivery cycles, enabling high efficiency (SCR) selective catalytic reduction of NOx in challenging operations. In low temperature exhaust, EHM frees the injected droplets from relying on the heat of the exhaust. It provides thermal energy to swiftly heat and evaporate the droplets, accelerating their thermolysis and hydrolysis reactions. Designed to be compact, low cost and robust, EHM forms plenty of reductants (ammonia, isocyanic acid) while mitigating the deposit risks. It has been tested on an engine in highly transient, low-load cycles exhibiting robust SCR of NOx well below 200 °C in long cycles with urea injection starting in as low as 130 °C. The mixer has been evaluated on a light duty Diesel engine using a purged (no-ammonia-stored) SCR catalyst simulating extended stop-and-go operations, demonstrating 99–100% NOx reduction efficiency during "stops" (idling) at 180 °C, and 80 to 95% during fast transients at 160 °C, while inhibiting deposit formation. These results were achieved without any engine or system calibration. EHM needs less than 200 W to operate on a light duty Diesel engine, and about 500 W on a heavy-duty engine. Given its thermal energy, it can be also used during cold-starts or cold-cycles for rapid-heatup of the SCR catalyst(s). EHM can also enable high engine-out NOx strategy so for fuel economy and reduced CO2. [ABSTRACT FROM AUTHOR]

Increased compression ratio of auto engine can effectively improve thermal efficiency. However, the risk of engine knock becomes higher when increasing the intake boosting. In this paper, the role of an inlet Water Injection (WI) system in improving the performance of a spark ignition engine was investigated, which was through a comparative study of Miller cycle with electromagnetic intake valve train (EMIT). The numerical simulation method was developed in AVL BOOST based on the engine test rig, and then the port water injection modelling was introduced. The results showed that when the engine speed was lower than 1800 r/min, the water spray scheme had a better effect on the engine performance as compared with the Miller cycle, and such advantage was increasingly significant with the decrease of the speed. This is due to the fact that the water injection takes into account the temperature reduction in the cylinder. When the engine speed was over 1800 r/min, it had a negative impact on engine performance with IWI due to the excessive suppression of combustion. This study provides a theoretical basis for design and research of gasoline engines. [ABSTRACT FROM AUTHOR]

The use of digital models of cultural heritage objects obtained from 3D scanning or photogrammetry requires the development of strategies in order to optimise computational resources and enhance the user experience when they are used in interactive applications or virtual museums. Through a case study, this work compares an original photogrammetric model with its optimised version using traditional remeshing techniques and an improved version using Nanite technology, developed by Epic Games. A self-contained executable is created in Unreal® 5.1 game engine to test the performance of the three models measured in frames per second (FPS). As a result, it was demonstrated that, although there is no substantial difference in the FPS rate, the Nanite technology avoids the need to perform the mesh and texture editing processes that lead to the construction of the optimised model. This saves considerable time and specialised effort, as the photogrammetric model can be converted to a Nanite object automatically. This would be a great advantage in the case of virtualisations of large collections of heritage objects, which is a common case in virtual museums. [ABSTRACT FROM AUTHOR]

This paper presents a special analysis study about the gas turbine operating line, and an overall description of a gas turbines project, based on experimental data from two particular applications, in order to convert two different types of aero engines into the same engine configuration. The experimental works were carried out with the aim of converting an Ivchenko AI-20K turboprop and a Rolls-Royce Viper 632-41 turbojet into free turbine turboshaft engines, to be used in marine propulsion, and also to obtain an experimental database to be used in other gas turbine applications. In order to carry out the experimental work, the engines were tested in turbojet configuration, to simulate the free turbine load by using jet nozzles with different geometries of the outlet cross-section. Following the engines' tests, a series of measured data were obtained, through which it was possible to experimentally determine the operating line of some engine components such as the compressor, turbine, and exhaust jet nozzle. This paper is comprehensive and useful through its scientific and technical guidelines, the operation curves coming in handy in the thermodynamic analysis and testing methodology for researchers dealing with similar applications. [ABSTRACT FROM AUTHOR]

This study aims to evaluate the use of ethanol/gasoline fuel blends in a single-cylinder spark-ignition engine with energy, exergy, exergoeconomic and exergoenvironmental analysis. Test fuels (G100, E10, E20, E30, E40, E50, and E100) prepared by adding ethanol obtained from agricultural products to gasoline at different ratios were utilized in experimental studies. Thermodynamic analyses were carried out using the performance and emission data obtained from the engine tests. Thermal efficiency and exergy efficiencies were computed with energy and exergy analyses. The highest efficiencies were acquired at 2500 rpm for all fuels. The exergy efficiency of G100, E20 and E40 fuels at this engine speed is 17.13%, 15.81% and 14.62%, respectively. Furthermore, cost of engine shaft work in exergoeconomic analysis and environmental cost of shaft work in exergoenvironmental analysis were found in study. When an engine speed was 2500 rpm in E50 fuel, the cost of shaft work was 74.21 $ MJ−1, and the environmental cost of shaft work was 59.07 $ GJ−1. Moreover, exergoeconomic factor and exergoenvironmental factor values of fuel blends were computed. It was revealed that increased ethanol ratio in fuel blends increased economic and environmental costs. In terms of economy and environment, it can be considered appropriate that the ethanol ratio in fuel blends is between 30 and 40%. If ethanol is used higher than these rates, costs increase and fuels become uneconomical. [ABSTRACT FROM AUTHOR]

The need for reducing fossil fuel consumption and greenhouse gas (GHG) emissions in internal combustion engines has raised the opportunity for the use of renewable energy sources. For the progressive replacement of fossil fuels like diesel, those derived from the sustainable management of forest resources may be a good option. In Portugal, pine trees (pinus pinaster) are among the most widely cultivated tree species. Turpentine can be extracted from their sap without harming the tree. Turpentine is known to be a good fuel with a lower viscosity than regular diesel but with a comparable caloric value, boiling point and ignition characteristics, although it is not widely used as a compression ignition fuel. Moreover, recent research has highlighted the possibility of substantially increasing the turpentine yield through biotechnology, bringing it closer to economic viability. The present study investigates the performance, pollutant emissions and fuel consumption of a 1.6 L four-cylinder direct-injection diesel engine operating with several blends of commercial diesel fuel and turpentine obtained from pine trees. The aim of this study was to assess whether it would be possible to maintain or even improve the performance, fuel consumption and GHG and pollutant emissions (HC, NOx, CO and PM) of the engine with the partial incorporation of this biofuel. Turpentine blends of up to 30% in substitution of regular diesel fuel were tested. The main novelties of the present work are related to (i) the careful testing of a still-insufficiently studied fuel that could gain economical attractiveness with the recent developments in yield improvement through biotechnology and (ii) the tests conducted under fixed engine load positions typical of road and highway conditions. The addition of this biofuel only slightly impacted the engine performance parameters. However, a slightly positive effect was observed in terms of torque, with an increase of up to 7.9% at low load for the 15T85D mixture and 6.8% at high load being observed. Power registered an increase of 9% for the 15T85D mixture at low speed and an increase of 5% for the 30T70D mixture at high speed when compared to the reference fuel (commercial diesel fuel). While the efficiency and fossil GHG emissions were improved with the incorporation of turpentine, it had a mixed effect on polluting emissions such as unburned hydrocarbons (HC) and smoke (PM) and a negative effect on nitrogen oxides (NOx). NOx emissions increased by 30% for high loads and 20% for low loads, mainly as an indirect effect of the improvement in the engine performance and not so much as a consequence of the marginally higher oxygen content of turpentine relative to commercial diesel fuel. [ABSTRACT FROM AUTHOR]

Copyright of CIRCULO de Linguistica Aplicada a la Comunicacion is the property of Universidad Complutense de Madrid and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Stirling engines take attention due to their high thermal efficiency potential. Many experimental and numerical studies have been performed up to date. Numerical performance analyses of Stirling engines implemented with CFD simulations are classified as 4th order analyses. In the present study, the effect of compression ratio on engine performance of a beta type Stirling engine with rhombic mechanism was investigated by 2D CFD simulation. CFD simulations of the Stirling engine were performed by ANSYS Fluent software. The engine examined by CFD analysis was modeled using the dimensions of an engine manufactured and tested in a previous study, and validation of the CFD simulation was conducted regarding in‐cylinder pressure at 4 bar charge pressure. The crank radius and length of the regenerator zone of the engine were optimized by considering the compression ratio of the engine and engine performance was investigated. Maximum engine performance was obtained at a compression ratio of 2.24 which was ensured by 31.5 mm crank radius and 609.9 mm a length of the regenerator zone. By optimizing the dimensions the engine performance was improved by 99% compared to the base engine configuration. The cyclic work, power, torque, and thermal efficiency were calculated as 62.47 J, 728.93 W, 9.94 Nm, and 37.7% respectively. [ABSTRACT FROM AUTHOR]

Engine oil forms a complex system with a number of features. These features consist of hydrocarbons, various natural, or synthetic polymers. The irradiation of polymers becomes an integral part of modern industry. The lubrication, charge, thermal and cleaning requirements, which engine oils are expected to meet, are often chemically contradictory and manufacturers have to decide to compromise. Electron accelerators are widely used to enhance polymer properties. By applying radiation technology, it is possible to increase the desirable properties of polymers while leaving other properties at their original value. The paper focuses on combustion engine oil modified by e-beam. The assessed engine oil has a hydrocarbon base, which, from the chemical point of view, is processed as a polymer during the irradiation process. In this paper we have compared selected properties of the conventional and the irradiated engine oil during two exchange intervals. We have examined appropriate dose, dose rate, irradiation volume and a container on a single accelerated electrons energy. The examined oil properties were of a physical and physico-chemical nature, and included mainly kinematic viscosity, viscosity index, the total base number, soot content, oxidation, sulfation, significant chemical elements and wear particles. Every oil attribute is compared with its original value. The main objective of this paper is to demonstrate that the application of e-beam is an adequate method used to enhance engine oil properties to achieve cleaner engine running, and extend engine oil lifetime. [ABSTRACT FROM AUTHOR]

The current research work focus on the utilization of hydrogen as a fuel in CI engine has been increased tremendously, since it is a zero-emission fuel. But higher self-ignition temperature than conventional fuel, makes to operate in dual fuel mode condition in CI engine. The diesel or biodiesel along with hydrogen in a CI engine results in the improvement in the performance but increase of NO. In order to minimize the NO emission, addition of ethanol with jamun B20 biodiesel blend (biodiesel-diesel-ethanol) and two ternary blends such as B20E05 and B20E10 are formed. In the present study, biodiesel along with H 2 is admitted in the CI engine. Ethanol addition reduces combustion temperature and act as cetane improver for the biodiesel. This induces better combustion of the fuel and reduce NO. The biodiesel production from jamun seed is carried out through transesterification process. H 2 of 4 lpm is allowed at the air inlet and jamun B20 blend is injected through the fuel injector. Improvement of brake thermal efficiency and increase in the NO are observed for the hydrogen with biodiesel operated CI engine. The performance and emission behaviors of CI engine done for the test samples. At full load condition (ternary blend) B20E05 assisted H 2 shows the drastic reduction of NO emission of 8.2% than B20 assist H 2 blend. In other hand emission like hydrocarbon, carbon monoxide and smoke opacity show a notable reduction for B20E05 blend assist H 2 than other test sample fuel. The thermal efficiency is 30.98% for B20E05 assist H 2 and it is 7.55% and 4.7% higher than B20 and B20E05 assist H 2 blend respectively. [Display omitted] • Ternary blends with hydrogen shows higher BTE. • Ternary blends of B20E05 shows 7.7% reduction of NO than B20 aided H 2. • B20E05 aided H 2 has higher heat release rate of 87/°CA. [ABSTRACT FROM AUTHOR]

Lubricated tribosystems such as main-shaft bearings in gas turbines have been successfully diagnosed by oil sampling for many years. In practice, the interpretation of wear debris analysis results can pose a challenge due to the intricate structure of power transmission systems and the varying degrees of sensitivity among test methods. In this work, oil samples acquired from the fleet of M601T turboprop engines were tested with optical emission spectrometry and analyzed with a correlative model. Customized alarm limits were determined for iron by binning aluminum and zinc concentration into four levels. Two-way analysis of variance (ANOVA) with interaction analysis and post hoc tests was carried out to study the impact of aluminum and zinc concentration on iron concentration. A strong correlation between iron and aluminum, as well as a weaker but still statistically significant correlation between iron and zinc, was observed. When the model was applied to evaluate a selected engine, deviations of iron concentration from the established limits indicated accelerated wear long before the occurrence of critical damage. Thanks to ANOVA, the assessment of engine health was based on a statistically proven correlation between the values of the dependent variable and the classifying factors. [ABSTRACT FROM AUTHOR]

Due to increasingly stringent limits for NOx emissions, there is now more interest than ever in cost-effective, precise, and durable exhaust gas sensor technology for combustion processes. This study presents a novel multi-gas sensor with resistive sensing principles for the determination of oxygen stoichiometry and NOx concentration in the exhaust gas of a diesel engine (OM 651). A screen-printed porous KMnO4/La-Al2O3 film is used as the NOx sensitive film, while a dense ceramic BFAT (BaFe0.74Ta0.25Al0.01O3–δ) film prepared by the PAD method is used for λ-measurement in real exhaust gas. The latter is also used to correct the O2 cross-sensitivity of the NOx sensitive film. This study presents results under dynamic conditions during an NEDC (new European driving cycle) based on a prior characterization of the sensor films in an isolated sensor chamber with static engine operation. The low-cost sensor is analyzed in a wide operation field and its potential for real exhaust gas applications is evaluated. The results are promising and, all in all, comparable with established, but usually more expensive, exhaust gas sensors. [ABSTRACT FROM AUTHOR]

Yttrium aluminum garnet thermal barrier coatings (TBCs) deposited by the solution precursor plasma spray process (SPPS) have been shown to have a 200 °C temperature advantage compared to air plasma spray yttria-stabilized zirconia TBCs (Gell et al. in J Therm Spray Technol 27:1-13, 2018). These properties were generated on specimens and included phase stability to 1900 °C, improved sinter resistance, reduced thermal conductivity, and enhanced CMAS resistance. Part I of this paper describes the development of the SPPS processing parameters with different microstructures for three solar engine components (fuel nozzle injectors, annular combustor, and turbine ceramic outer air seals). This Part II paper describes the technology transfer to Solar Turbines Incorporated, coating of the three components and the successful rig and engine tests. [ABSTRACT FROM AUTHOR]

This article characterises the methodology for the endoscopic testing of a laboratory diesel engine used for testing marine fuels. The 'Shadow' measurement method used in the XLG3 type EVEREST digital endoscope, for quantitative and qualitative identification of detected surface defects, was approximated. Representative endoscopic images of the elements limiting the working space of the research engine are demonstrated, having been recorded during the usable quality testing of newly produced, low-sulphur marine fuels, so-called 'modified fuels'. The main purpose of the endoscopic examinations was the final verification of the tested fuel's suitability for feeding full-size marine engines. [ABSTRACT FROM AUTHOR]

A single cylinder low powered diesel engine of 3.5kW was modified to run on Common rail direct injection high pressure split injection system. This modified engine was tested to run on the neat diesel with ultra-cooled exhaust gas recirculation. The adjustable working parameters i.e., injection pressures 200bar, 230bar, 250bar, 300bar and 350bar, retarded injection -11°, split injection -54°and -11°. After Top dead center position, Exhaust gas recirculation flow rates 5% & 10% respectively are tested on this engine under two typical operating conditions of ? full load of 0.875kW and ? full load of 2.625kW respectively. Single factor and multifactor orthogonal quadratic regression analysis has been carried to determine the effect of these 4 working parameters on engine emissions NOx. The mathematical equations characterizing the relationship between these 4 operating variables are formed. The equation of the NOx and noise was from the orthogonal regressive test under 1/4 Full load and ? Full load conditions was set as the objective function and the ranges of these 4 working variables are given as the constraint condition. Models of non-linear programming were then formulated and solved by using statistical analytical software. Test results showed that 10% Single Injection generates NOx of 194.87 parts per million while 10% Multiple fuel injection generates 199 while the minimum NOx that can be produced is 134.27. [ABSTRACT FROM AUTHOR]

Recently, microbial oil has become one of the promising next-generation feedstocks for producing biodiesel. While microbial oil can be extracted from different sources, there is only limited work on microbial production from fruits and vegetables. In this work, biodiesel was extracted through a two-step process: microbial conversion of vegetable waste into microbial oil using Lipomyces starkeyi, followed by transesterification of microbial oil into biodiesel. The lipid accumulation, composition of microbial oil, and the fuel properties of biodiesel were evaluated. The microbial oil consisted mainly of C16:0, C18:0 and C18:1, which were close to the properties of palm oil. The fuel properties of biodiesel comply with the EN14214:2012 standard. Thus, the vegetable waste can be a good biodiesel feedstock. Three blends (MOB10, MOB20 and MOB30 with 10, 20, and 30% of biodiesel) were tested for engine performance and emission characteristics in a 3.5 kW VCR research engine. At full load, MOB20 reduced the pollutant emissions of CO and HC by 47.8% and 33.2% with the penalty of increased NOx by 3.9%, while BTE reduced by 0.8% with the increased BSFC by 5.2%. Thus, the addition of vegetable waste biodiesel blends reduced the emissions of CO and HC significantly with slight reduction of brake thermal efficiency. [ABSTRACT FROM AUTHOR]

At partial load, traditional automotive gasoline engines have high pumping losses due to the throttling of the intake charge for load control. Variable Valve Timing (VVT) and the introduction of externally cooled EGR could reduce the pumping losses but only with a very limited effect. On the other hand, in the medium to full load range, the engine cannot utilize a high compression ratio due to limitations in knocking. A variable displacement, variable compression ratio device which utilizes an asymmetric camshaft to realize the different closure times of the two intake valves is discussed in this paper. The large-scale change in the intake valve timing leads to the large-scale change in the effective cylinder volume at the intake valve closure, which realizes a variable cylinder volume and a variable effective compression ratio. The device is utilized to reduce the pumping losses and to increase the in-cylinder thermal efficiency at the same time. Engine dyno test results indicate that, in the low to medium load range, a later closure of the intake valve could reduce the effective cylinder volume, and the intake pressure could be significantly increased, and therefore pumping losses reduced. However, the reduced effective cylinder volume due to a later intake valve closure would lead to reduction in the effective compression ratio (ECR) and a drop in in-cylinder thermal efficiency. Therefore, there is a balance point between the pumping loss reduction and the drop in in-cylinder thermal efficiency. On the other side, in the medium to full load range, when avoiding knocking becomes the major controlling factor of the combustion phasing (degree of constant-volume combustion) and the effective expansion ratio (EER), too high of an effective compression ratio would lead to significant drop in the effective expansion ratio EER and also the in-cylinder thermal efficiency. Therefore, there exists a best compromise between the ECR and EER, and the best system would be one with a moderate ECR but an EER as high as possible. The quantitative equations which include both ECR and EER in the thermal efficiency calculations captured the above observations pretty well and can be utilized to optimize for the best compromise of IVC, EVO, ECR, EER and engine performances during the concept stage and/or the calibration stage of an engine. [ABSTRACT FROM AUTHOR]

The engine management system (EMS) is arguably one of the most critical and complex components of a spark ignition (SI) engine. Modern EMS incorporates various components (like sensors, actuators, control strategies, etc.) to achieve an appropriate engine response. Even though EMS has been researched for a long time, most existing studies have just focused on individual control modules with no consideration about their interaction or how they work when brought together. For this reason, this paper presents the entire design, implementation and testing of EMS for a SI system. In particular, this investigation shows each EMS module, along with tests of the EMS. In addition, we carried out numerous experimental tests (such as stability analysis, reference tracking, and disturbance rejection) to assess the custom EMS. From vehicle performance test, we obtained a slight power (1.2%) and torque (1.3%) percentage errors between custom and original EMS. Similarly, percentage error obtained for vehicle emission tests for hydrocarbons (HC), carbon monoxide (CO), and nitrogen oxides (NOx) are 29.2%, 21.4% and 65.9%, respectively, which highlighted a slightly richer mixture once compared to custom with the original EMS. Lastly, experiment results show the success of the proposed EMS. [ABSTRACT FROM AUTHOR]

The effects of performance and emission parameters of a mono-cylinder CI engine have been studied using new alternate fuel: Lemongrass oil (LGO) with nano additive (Cerium Oxide). The study focuses on a novel biosynthesis method (Plant-mediated synthesis) of CeO2 nano-additives from the Azadirachta indica plant, which is less toxic and more compatible with other chemical methods. The biosynthesis method is a simple, high-yielding, environmentally friendly alternative to chemical methods. Recently, a green technique based on impulsively decreasing elements such as polysaccharides, microorganisms (bacteria and fungas), or plant extract has been developed. This is due to the fact that the process is a simpler, non-hazardous, and environmentally friendly alternative technique when compared to the intricate chemical techniques of synthesis of nano-additives. The engine tests were carried out by using three different volumetric percentages (LGO25, LGO25 + 50 ppm and LGO25 + 100 ppm) and related with base diesel. The test outcomes revealed that the BSFC decreased by 4.98% and 6.83% and BTE increased by 1.76% and 2.27% at LGO25 + CE 50 ppm and 100 ppm concentrations, correspondingly. The CO emission decreased by 18.18% and 24.2%, HC emission decreased by 3.03% and 9.1%, NOx emission decreased by 14.8% and 31%, Smoke emission decreased by 10.5% and 15.1% for LGO25 + CE 50 ppm and 100 ppm correspondingly. [ABSTRACT FROM AUTHOR]

The mandatory implementation of the standards laid out in the Energy Efficiency Existing Ship Index (EEXI) and the Carbon Intensity Indicator (CII) requires ships to improve their efficiency and thereby reduce their carbon emissions. To date, the steam Rankine cycle (RC) has been widely used to recover wasted heat from marine main engines to improve the energy-conversion efficiency of ships. However, current marine low-speed diesel engines are usually highly efficient, leading to the low exhaust gas temperature. Additionally, the temperature of waste heat from exhaust gas is too low to be recovered economically by RC. Consequently, a solution has been proposed to improve the overall efficiency by means of waste heat recovery. The exhaust gas is bypassed before the turbocharger, which can decrease the air excess ratio of main engine to increase the exhaust gas temperature, and to achieve high overall efficiency of combined cycle. For quantitative assessments, a semi-empirical formula related to the bypass ratio, the excess air ratio, and the turbocharging efficiency was developed. Furthermore, the semi-empirical formula was verified by testing and engine model. The results showed that the semi-empirical formula accurately represented the relationships of these parameters. Assessment results showed that at the turbocharging efficiency of 68.8%, the exhaust temperature could increase by at least 75 °C, with a bypass ratio of 15%. Moreover, at the optimal bypass ratio of 11.1%, the maximum overall efficiency rose to 54.84% from 50.34%. Finally, EEXI (CII) decreased from 6.1 (4.56) to 5.64 (4.12), with the NOx emissions up to Tier II standard. [ABSTRACT FROM AUTHOR]

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The marine engine is a complex-structured multidisciplinary system that operates in a harsh environment involving high temperatures and pressures and gas/fluid/solid interactions. Many malfunctions and faults can occur to the marine engine and efficient condition monitoring is critical to ensure the expected performance. In this paper, a marine engine test rig is established and its process data are recorded, including various temperatures and pressures. Two data-driven models, i.e., principal component analysis and the sparse autoencoder, and a physics-based model are applied to the marine engine for two classic faults, i.e., lubrication oil filter blocking and cylinder leakage. Comparative studies and discussions are conducted regarding their performance in terms of anomaly detection and fault isolation. The data points collected for the filter blocking fault are generally two times higher than the fault thresholds set by the data-driven models. In the physics-based model, it is observed that the lubrication oil pressure falls from the predicted 3.2–3.8 bar to around 2.3 bar. For the cylinder leakage fault, the fault test data are nearly four times higher than the thresholds in the data-driven models. The exhaust gas temperature of the leaked cylinder falls from an estimated 150–200 °C to about 100 °C. The transferability and interpretability of these models are finally discussed. The findings of the present study offer insights into the two types of models and can provide guidance for the effective condition monitoring of marine engines. [ABSTRACT FROM AUTHOR]

Several types of alternative fuels have been developed to replace fossil fuels. Alcohols, such as ethanol and methanol, can be blended with gasoline for spark ignition (SI) engines. High octane number and oxygen content in alcohol can increase combustion efficiency. Therefore, our current research investigates the effect of high concentrations of ethanol and methanol mixed in RON 90 gasoline. The mixture was implemented in a 150 cc single-cylinder fourstroke spark ignition (SI) engine without any modifications. Engine testing was carried out with wide-open throttle (WOT) and different engine speeds from 4000 to 10000 rpm. Torque, power, and Air Fuel Ratio (AFR) were measured during experiments on a chassis dynamometer. Our test results found that the higher the methanol fraction in the mixture, the lower the torque generated. To improve engine performance, further research is needed on modified engines so that optimal conditions can be identified. [ABSTRACT FROM AUTHOR]

Bird strikes have long been a source of concern for all airlines across the world. It is the most significant design criterion for aircraft engine fan blades. As it is not practical to manufacture and test aviation engines repeatedly for minor design modifications, simulation analysis can be used to investigate strategies to reduce the influence of a bird strike on a jet engine by employing proper design and manufacturing processes for blades. This study proposes using two fibers (hybrid) instead of the single-fiber composite blade presently in use to address delamination problems. As an idea validation test, the coupon-level analysis results are validated using a four-point bend test of similar-size coupons. Following this validation, dynamic analysis is used to investigate the impact behavior of a rectangular plate subjected to a bird strike. The current research focuses on analyzing bird strikes on a hybrid composite fan blade using blade-level models. This study concentrates on the position of the bird's impact and the joint region length of two materials. The results show that the joint region with a 40% length of glass composite shows the optimum level of normalized interlaminar shear strain in all three impact locations. [ABSTRACT FROM AUTHOR]

This study presents a resistive sensor concept based on Barium Iron Tantalate (BFT) to measure the oxygen stoichiometry in exhaust gases of combustion processes. The BFT sensor film was deposited on the substrate by the Powder Aerosol Deposition (PAD) method. In initial laboratory experiments, the sensitivity to pO2 in the gas phase was analyzed. The results agree with the defect chemical model of BFT materials that suggests the formation of holes h • by filling oxygen vacancies V O • • in the lattice at higher oxygen partial pressures pO2. The sensor signal was found to be sufficiently accurate and to have low time constants with changing oxygen stoichiometry. Further investigations on reproducibility and cross-sensitivities to typical exhaust gas species (CO2, H2O, CO, NO, ...) confirmed a robust sensor signal that was hardly affected by other gas components. The sensor concept was also tested in real engine exhausts for the first time. The experimental data showed that the air-fuel ratio can be monitored by measuring the resistance of the sensor element, including partial and full-load operation modes. Furthermore, no signs of inactivation or aging during the test cycles were observed for the sensor film. Overall, a promising first data set was obtained in engine exhausts and therefore the BFT system is a possible cost-effective alternative concept to existing commercial sensors in the future. Moreover, the integration of other sensitive films for multi-gas sensor purposes might be an attractive field for future studies. [ABSTRACT FROM AUTHOR]

Automobiles use compression-ignition (CI) engines because they have more pulling power, are more dependable and use less fuel than spark-ignition (SI) engines. Both CI and SI engines use petroleum-based oils, contributing to environmental pollution like acid rain, ozone depletion and climate change. The cost of petroleum-based fuel is increasing daily due to demographic growth and the development of manufacturing industries. There are four phases to the experiments. The first stage involves mixing diesel with 20% of ALME, the outcomes showed that engine operation and combustion are comparable to conventional diesel fuel. In the second stage, an LHR engine tests 20% of ALME and the results showed that BTE of LHR engine had significantly increased. In comparison, NOx increases in LHRoperated CI engine, CO, HC and smoke emissions are significantly lower than with a conventional engine. The third stage looks at how NA interacts with biodiesel to affect conventional engine's combustion, emission and engine performance. The prepared algae biodiesel is blended with NA in various ratios of 500ppm, 1000ppm, 1500ppm and 2000ppm. At 1000ppm concentration, NOx emission from conventional and LHR engines has been effectively minimized under load conditions. Concerning diesel fuel, emissions like CO, HC and smoke are significantly reduced for all loads. In the fourth stage, tests on the LHR engine are carried out using the SBME with NA in various proportions. When compared to base fuel, it has been found that NOx emission has decreased significantly at 1000ppm compared to conventional engines and other emissions have decreased. [ABSTRACT FROM AUTHOR]

The stratosphere is the atmospheric layer with the strongest impact on long-range infrasound propagation. Natural and anthropogenic infrasound signals are efficiently ducted between refraction altitudes of 30 to 60 km and reflections on the ground and are thus propagated to infrasound receivers over long distances. The direction of favorable stratospheric ducting depends on the state of the atmosphere, primarily driven by the seasonal variation of stratospheric winds. This study uses a dataset of ground-truth infrasound events over two decades and all seasons to assess the station detectability and atmospheric model performance to correctly estimate according station observations and propagation conditions. From 2000 to 2019, the German Aerospace Center facility in Lampoldshausen has conducted ignition tests of the Ariane 5 main rocket engine. Out of the 159 engine tests considered in this study, 71 were observed at the infrasound array IS26 in the Bavarian forest, located eastward at 320 km distance. Observations were mostly made during wintertime, whereas reversed stratospheric wind patterns during summertime inhibited signal detections. A significant portion of wintertime non-detections however corresponded to stratospheric profiles that should enable signal observations. Using European Centre for Medium-Range Weather Forecasts (ECMWF) atmospheric model analyses and infrasound ray tracing only two-thirds of the non-detections could be explained by the existence of a near-station acoustic shadow zone. It must thus be concluded that the applied atmospheric model is more often than expected unable to correctly explain infrasound propagation and observation at regional distances. [ABSTRACT FROM AUTHOR]

The OpenFOAM computational fluid dynamics code was used to investigate the performance of three combustion models, namely, Muppala, Zimont and Algebraic. The performance characteristics of these models were tested in a fully premixed (stoichiometric Φ = 1.0 ) modern, high-performance 4-valve, iso-octane, dual overhead cam (DOHC) engine with quasi-symmetric pent roof combustion chamber running at 1500 revolutions per minute. The performance characteristics of the three combustion models were found to be reasonably representative of measurement data that are usually observed in internal combustion engine test bed experiments. The combined or overall duration Δ θ o , of the flame development Δ θ d and propagation period Δ θ b ′ for the three models were 5.53 ms, 5.69 ms and 6.04 ms for the Muppala, Zimont and Algebraic models, respectively, and these values correspond to 49.75◦CA, 51.175 CA and 54.425 CAwhich are well within the 30 ≤ Δ θ o ≤ 90 acceptable degree crank angle range during typical internal combustion engine operations. The maximum pressure with the corresponding degree crank angle positions at which they occur for the Muppala, Zimont and Algebraic models were found to be: 59.86 b a r , 6.83 ∘ C A , 53.19 b a r , 11.9 ∘ C A and 47.64 b a r , 12.1 ∘ C A respectively. Furthermore, the results from the present study show that the flame-development period Δ θ d , was almost identical for the three combustion models, whereas the rapid-burning interval Δ θ b , was almost indistinguishable for the three combustion models up to about the 80% mark of the regress variable. In specific terms, the complete salient findings from this study are summarised in the conclusion section of this study. [ABSTRACT FROM AUTHOR]

Helical springs with nonlinear geometric parameters nowadays have shown great advantages over classical linear springs, especially due to their superior performance in diminishing dynamic responses in high-speed situations. However, existing studies are mostly available for springs with linear properties, and the sole FE spring models using solid elements occupy significant computational resources. This study presents an FE spring model based on Timoshenko beam theory, which allows for high-speed dynamic simulations of nonlinear springs using a beehive valve spring sample. The dynamic results are also compared with the results of the FE model using solid elements and the results of the engine head test and indicate that the proposed FE model can accurately predict dynamic spring forces and the phenomenon of coil clash when simulating the beehive spring at engine speeds of both 5600 and 8000 RPM. The results also indicate that rapid coil impact brings significant spike forces. It should also be noted that the FE spring model using beam elements displays sufficient accuracy in predicting the dynamic responses of nonlinear springs while occupying much fewer computational resources than the FE model using solid elements. [ABSTRACT FROM AUTHOR]