ВИЗНАЧЕННЯ ЗОВНІШНІХ ШВИДКІСНИХ ХАРАКТЕРИСТИК СИЛОВОГО ОБЛАДНАННЯ ДОРОЖНІХ МАШИН

In this investigation, the influence of using the EFWP filter on the tractor exhaust emissions was determined. A Water and paper filter is a filter designed to operate as a filter for the exhaust for the reduction of the harmful gas (CO, CO2, NOx, and HC) emission from the engine of the tractor. Emissions experiments were carried out on CASE JX75T tractor at different engine speeds are 750, 1000, 1250, 1500, 1750, 2000, and 2250 rpm. All engine speed of the tractor underwent experimentation before the installation of the EFWP filter and after installation it. The noises and Bsfec also were measured when the two cases. Each engine speed was tested for approximately 20 minutes in two cases. The results showed a significant (P≤0.05) decreasing in carbon monoxide CO (51.40%), carbon dioxide CO2 (25%), nitrogen oxides NOx (43.43%) and hydrocarbons HC (60.98%) emissions and also, the noises reduced by 25.38% and there was no significant increase in the BSFC (5.34% only) after the EFWP filter was put in the tractor exhaust. The results also showed that increasing the engine speed from 750 to 2250 rpm led to significant increases in CO2, NOx, and HC emissions, while decreased the CO emission. Also, the increased by a percentage of 155.88 and 159.38 % in the case using the EFWP filter and without using it (the ordinary case) respectively. Using the EFWP filter reduced the noises not overridden internationally permitted standards (65 dB).

Power engineering enterprises have a great impact on the environment. Flue gas emissions contain solid ash particles, sulfur oxides SO2, SO3, nitrogen oxides NOx, carbon monoxide CO (monoxide) CH hydrocarbons; in some cases, there may be a danger of radiation contamination, but the most dangerous substance emitted into the atmosphere is benzo(a)pyrene C20H12, which has a negative effect on human health. Polycyclic aromatic hydrocarbons (PAH), including benzo(a)pyrene contained in flue gas emissions from energy enterprises, have a serious impact on human health. Taking measures to suppress other harmful emissions from thermal power plants (nitrogen oxides and sulfur oxides) can increase the content of benzo(a)pyrene, which poses a serious problem for modern researchers. As part of this study, various technologies for suppressing benzo(a)pyrene emissions at energy enterprises were considered. The main disadvantages of the described methods are highlighted. The possible danger of increasing benzo(a)pyrene emissions when trying to suppress other emissions is noted.

This study is dedicated to investigations of the working process in a dual-fuel low-emission combustion chamber for a floating vessel’s gas turbine. As the object of the research, a low-emission gas turbine combustion chamber with partial premixing of fuel and air inside the outer and inner radial-axial swirls was chosen. The method of the research is based on the numerical solution of the system of differential equations which represent the physical process of mass and energy conservation and transformations and species transport for a multi-component chemically reactive turbulent system, considering nitrogen oxides formation and a discrete ordinates model of radiation. The chemistry kinetics is presented by the 6-step mechanism of combustion. Seven fuel supply operating modes, varying from 100% gaseous fuel to 100% liquid fuel, have been analysed. This analysis has revealed the possibility of the application of computational fluid dynamics for problems of dual-fuel combustion chambers for the design of a floating vessel’s gas turbine. Moreover, the study has shown the possibility of working in different transitional gaseous and liquid fuel supply modes, as they satisfy modern ecological requirements. The dependencies of the averaged temperature, NO, and CO concentrations along the length of the low-emission gas turbine combustion chamber for different cases of fuel supply are presented. Depending on the different operating modes, the calculated emission of nitrogen oxides NO and carbon monoxide CO at the outlet cross-section of a flame tube are different, but, they lie in the ranges of 31‒50 and 23‒24 mg/nm3 on the peak of 100% liquid fuel supply mode. At operating modes where a gaseous fuel supply prevails, nitrogen oxide NO and carbon monoxide CO emissions lie in the ranges of 1.2‒4.0 and 0.04‒18 mg/nm3 respectively.

The prospect of analysis-driven pre-calibration of a modern diesel engine is extremely valuable in order to significantly reduce hardware investments and accelerate engine designs compliant with stricter EPA fuel economy regulations. Advanced modeling tools, such as CFD, are often used with the goal of streamlining significant portions of the calibration process. The success of the methodology largely relies on the accuracy of analytical predictions, especially engine-out emissions. However, the effectiveness of CFD simulation tools for in-cylinder engine combustion is often compromised by the complexity, accuracy, and computational overhead of detailed chemical kinetics necessary for combustion calculations. The standard approach has been to use skeletal kinetic mechanisms (∼50 species) which consume acceptable computational time but with degraded accuracy. In this work, a comprehensive demonstration and validation of the analytical pre-calibration process is presented for a passenger car diesel engine using CFD simulations with CONVERGE™ and a GPU-based chemical kinetics solver (Zero-RK, developed at Lawrence Livermore National Laboratory) on high performance computing resources to enable the use of detailed kinetic mechanisms. Diesel engine combustion computations have been conducted over 600 operating points spanning in-vehicle speed-load map, using massively parallel ensemble simulation sets on the Titan supercomputer located at the Oak Ridge Leadership Computing Facility. The results with different mesh resolutions have been analyzed to compare differences in combustion and emissions (NOx, Carbon Monoxide CO, Unburned Hydrocarbons UHC, and Smoke) with actual engine measurements. The results show improved agreement in combustion and NOx predictions with a large n-heptane mechanism consisting of 144 species and 900 reactions with refined mesh resolution; however; agreement in CO, UHC and Smoke remain a challenge.

The problem of air basin pollution of the World Ocean with harmful emissions from the exhaust gases of marine diesel engines is primarily associated with the creation of highly efficient technologies for the neutralization of nitrogen oxides NOx on exhaust gases from a diesel engine. Emissions of harmful substances from the combustion of marine fuels are limited by international atmospheric protection programs and the requirements of the International Maritime Organization (IMO). The requirements relate to almost all groups of harmful emissions in marine engines and the more stringent of them are primarily related to nitrogen oxides NOx and sulfur oxides SOx. To reduce harmful emissions from exhaust gases into the environment, scientists and world engine leaders use and suggest various methods for reducing the content of harmful substances in exhaust gases. The implementation of new standards in the areas of further improvement of the working process, the use of alternative fuels, fuel, and air additives, as well as selective catalytic reduction systems do not preclude further development of scientific research in the field of exhaust gas cleaning. One of the promising ways in environmentalizing marine internal combustion engines is the neutralization of harmful substances in exhaust gases through particular gas recirculation (EGR-technology). However, the use of such techniques conflicts with the engine's energy efficiency. In the work presented, the scheme-design solution of the exhaust gas recirculation system with using the heat of recirculation gases by an ejector refrigeration machine for cooling the air at the intake of ship's main engine is proposed. The effect of using the heat of recirculation gases for cooling the air at the intake of the engine is analyzed taking into account the changing climatic conditions for a particular vessel's route line. It is shown that the use of an ejector refrigeration machine reduces the air temperature at the entrance of the main engine by 5…15 ° С, which reduces the specific fuel consumption. This reduces emissions of harmful substances when the engine is running with recirculation of gases.

Diesel engine is a type of internal combustion engines, convert chemical energy contained in the fuel into mechanical power. Diesel fuel is a mixture of hydrocarbons its complete combustion leads to formation of Carbon dioxide and Water Molecules. The in complete combustion leads to various pollutants like hydrocarbon HC, carbon monoxide, smoke, nitrogen oxide NOX. These harmful pollutants effects both human begins and environment to a greater extent. In this present work an attempt was made to reduce the emission from the Twin cylinder direct injection diesel by using various physical adsorbents. Activated carbon and zeolite were used as physical adsorbents to reduce emission from the exhaust gas. The silencer of the vehicle will be replaced by a newly design silencer which is designed to place the physical adsorbents. Computational analysis was carried out to optimize the back pressure developed in the adsorbent chamber. The conical length of adsorbent chamber is varied of about 68mm,75mm and 85 mm at exhaust temperature conditions 220 °C,300 °C and 350 °C respectively. The results obtained conveys that adsorbent chamber with 85mm convergence length has shown acceptable pressure drop.

The article considers the possibility of using biogas for vehicle engines, as an additive to compressed natural gas, and gives the results of experimental studies of environmental indicators and fuel efficiency of a vehicle equipped with a gasoline engine and converted to work on a mixture of biogas and compressed natural gas. Currently, there are many vehicles in operation that operate without feedback on the content of oxygen in the exhaust gases, they run on gasoline and gas motor fuels, in view of this, the results of these studies are very relevant. It has been proven that the use of biogas as motor fuel for vehicle engines reduces the energy dependence on petroleum fuels and reduces emissions of harmful substances in the exhaust gases of the vehicle engine, and the use of biogas as an additive to compressed natural gas will provide an opportunity not to spend additional resources for its purification. The use of biogas as a motor fuel confirms the possibility of its use in traditional constructions of vehicle engine power systems. With simple, reliable and proven production technologies, biogas can become a cost-effective and efficient type of fuel obtained from renewable sources. In this way, it is possible to satisfy these needs by using alternative types of fuels, one of these types of fuels is biogas, which is obtained in the process of anaerobic decomposition of organic waste. Biogas consists of methane CH4, carbon dioxide CO2, small amounts of carbon monoxide CO, hydrogen H2, nitrogen N2, oxygen O2, water vapor H2O and hydrogen sulfide H2S. The possibility of using a mixture of fuels, namely biogas as an additive to compressed natural gas, is substantiated. A comparative analysis of the fuel-economical and environmental performance of the vehicle engine in the modes of the European urban driving cycle was performed while the engine was running on compressed natural gas, a mixture of biogas and compressed natural gas, and liquid petroleum fuel gasoline brand A-92

The complete reduction of iron oxide on heating the initial Fe3O4–H2O–C system with isothermal holding is subjected to thermodynamic analysis. (Note that the initial system contains eo moles of Fe3O4 and bo moles of H2O, with excess carbon.) The processes in the system may be divided into four stages. First, the gasification of carbon by water vapor at temperatures below 880 K activates the reaction of the water gas and the dissociation of CO with the formation of lamp black (solid carbon). The composition of the H2–H2O–CO–CO2 gas mixture obtained depends only on the temperature. The carbon consumption at 880 K is ~0.445 mole per mole of water. The second stage, in the range 880–917 K, is the reduction of Fe3O4 to wustite FeO1+x with different degrees of oxidation. Hydrogen reduces the oxide at temperatures above 888 K. The proportion of the oxide reduced by hydrogen in this temperature range increases from zero to ~63%. The total quantity of Fe3O4 reduced to wustite at 917 K is ~123 moles per mole of water. This is only possible with repeated regeneration of the reducing agents CO and H2 as a result of the gasification of carbon by water vapor and carbon dioxide CO2. The carbon consumption is approximately 78 moles. In the third stage, the wustite FeO1.092 is reduced solely by carbon monoxide CO in the range 917–955°C to wustite FeO1.054, with a lower degree of oxidation. The carbon is only gasified by CO2; the carbon consumption is around 18 moles. In the fourth stage, with isothermal holding at ~955 K, the wustite is reduced to iron by carbon monoxide alone. The carbon consumption is around 257 moles. In a closed system at 1 atm, 1 mole of water is sufficient for the complete reduction of around 123 moles of Fe3O4 in a mixture with excess carbon. The total carbon consumption is ~353 moles, with the production of 368 moles of Fe; that is, the carbon consumption is ~0.21 kg/kg of iron.

Solving the problem of ocean's airspace polluting with harmful emissions of ship-generated diesel engines by exhaust gases is associated with the creation of highly effective technologies for the neutralization of nitrogen oxides NOx from the diesel plant that apply both to vessels in service, designed and built. The air entering the engine is a working fluid that carries out a certain thermodynamic cycle, resulting in a change in its chemical composition, and the exhaust gas mixture contains many components. Emissions of harmful substances during the combustion of marine fuels are limited in accordance with international programs for the protection of the atmosphere and requirements of the International Maritime Organization IMO. Requirements apply all groups of harmful emissions of marine engines. The most stringent of them concern nitrogen oxides NOx and sulfur oxides SOx. To reduce harmful emissions from the exhaust gases into the environment, scientists and world leaders in engine construction, such as MAN Energy Solutions and Wärtsilä, apply and offer a variety of techniques to reduce the number of harmful substances in the exhaust gases. One of the most promising is the exhaust gas recirculation system (EGRS) of the ship diesel engine. Its advantage over other methods is the insignificant impact on the operation of the engine. During the exhaust gas recycling a temperature of the flame in the combustion chamber decreases, which leads to the reduction of NOx number. This is a consequence of the high rates of carbon dioxide and water vapor. Since the combustion rate is reduced, the exhaust temperature and the thermal load on the engine part are increased. The dilution of the inflow air with waste gas reduces the oxygen content in the supercharged air from 21 to 13%. The possibilities of the technology of the system of recirculation of exhaust gases of a marine engine are limited by the value of the ratio of O2/CO2 in the intake air, due to which the amount of combustion products at the inlet is limited to no more than 30%

We have built a prototype submillimeter spectrometer, FIBRE, which is based on a helium-cooled scanning Fabry-Perot and superconducting transition edge sensor bolometers (TES). SQUID multiplexers are used to read out the individual detector pixels. The spectral resolving power of the instrument is provided by the Fabry-Perot spectrometer. The outgoing light from the Fabry-Perot passes onto a low resolution grating for order sorting. A linear bolometer array consisting of 16 elements detects this dispersed light, capturing 5 orders simultaneously from one position on the sky. With tuning of the Fabry-Perot over one free spectral range, a spectrum covering Δλ/λ=1/7 at a resolution of ~1/1200 can be achieved. The spectral resolution is sufficient to resolve doppler broadened line emission from external galaxies. FIBRE operates in the 350 μm and 450 μm bands. These bands cover line emission from the important PDR tracers neutral carbon [CI] and carbon monoxide CO. The spectrometer was used at the Caltech Submillimeter Observatory to obtain the first ever astronomical observations using multiplexed arrays of superconducting transition edge bolometers.

Thin films of single-crystal silicon carbide of cubic polytype with a thickness of 40–100 nm, which were grown from the silicon substrate material by the method of coordinated substitution of atoms by a chemical reaction of silicon with carbon monoxide CO gas, have been studied by spectral ellipsometry in the photon energy range of 0.5–9.3 eV. It has been found that a thin intermediate layer with the dielectric constant corresponding to a semimetal is formed at the 3C-SiC(111)/Si(111) interface. The properties of this interface corresponding to the minimum energy have been calculated using quantum chemistry methods. It has turned out that silicon atoms from the substrate are attracted to the interface located on the side of the silicon carbide (SiC) film. The symmetry group of the entire system corresponds to P3m1. The calculations have shown that Si atoms in silicon carbide at the interface, which are the most distant from the Si atoms of the substrate and do not form a chemical bond with them (there are only 12% of them), provide a sharp peak in the density of electronic states near the Fermi energy. As a result, the interface acquires semimetal properties that fully correspond to the ellipsometry data.

3-Oxetanone is a strained cyclic molecule which plays an important role in synthetic chemistry. A few studies exist in the literature about the equilibrium properties of this molecule and the dissociation patterns of substituted 3-oxetanones. For the unsubstituted 3-oxetanone, formation of ketene (CH2CO) and formaldehyde (HCHO) was considered to be the major dissociation pathway. In a recent work, pyrolysis products of 3-oxetanone molecule in the gas phase were investigated by Fourier transform infrared spectroscopy and photoionization mass spectrometry. In this study, an additional dissociation channel forming ethylene oxide (c-C2H4O) and carbon monoxide CO was reported. In the present work, gas phase dissociation chemistry of 3-oxetanone was investigated by electronic structure theory, ab initio classical chemical dynamics simulations, and Rice-Ramsperger-Kassel-Marcus (RRKM) rate constant calculations. The barrier height for the ethylene oxide channel was found to be much higher than the ketene pathway. The dynamics simulations were performed at three different total energies, viz., 150, 200, and 300 kcal/mol, and multiple reaction pathways and varying branching ratios observed. A new dissociation channel involving a ring-opened isomer of ethylene oxide was identified in the simulations. This pathway has a lower energy barrier and was dominant in our dynamics simulations.

<p>Changes in the atmospheric composition in different periods of 2020 in Moscow, associated with the COVID-19 pandemic preventing measures of varying intensity and with corresponding reduction in emissions of pollutants, were investigated. Surface concentrations of nitrogen dioxide NO<sub>2</sub>, carbon monoxide CO, ozone O<sub>3</sub>, aerosol fraction PM<sub>10</sub> and meteorological parameters in different periods of 2020 are compared with similar data for the previous 5 years. The analysis of ground-based measurements, as well as high-resolution satellite distributions of CO and NO<sub>2</sub>, indicated that the content of major pollutants and its spatial distribution in the Moscow region were significantly affected by both restrictive measures and abnormal meteorological conditions in 2020. It is possible to obtain quantitative estimates of the contribution of both factors using transport and chemical modeling based on detailed inventory of anthropogenic emissions.</p><p>Additionally, some characteristics of atmospheric composition long-term trends in Moscow region are analyzed and discussed.</p><p>The study was supported by Russian Science Foundation under grant №21-17-00210.</p>

Recently, the biomass gas is remarked as renewable energy. The practical effective utilization for the fuel is reported. Some of biomass gases are produced by the gasification with the gas furnace and by sewerage processing. The gas includes various species of components which are such inert gas as Nitrogen N_2, carbon dioxide gas CO_2 and flammable components as hydrogen H_2, methane CH_4 and carbon monoxide CO. The fuel calorific value depends on the ratio of each component. In this study, the diffusion flame is formed when the biomass gas spouts from the burner nozzle. The practical biomass gas BG and dilute hydrogen H_2 with mixing Nitrogen N_2 are used as the fuel. The characteristic of combustion of the low-calorie gas fuel is investigated. The objective of the present study is to get further understanding of lifting/blow-off and the flame structure with regard to the dilute diffusion flame of Low Calorie Biomass Gas. It is found that the biomass gas is effective as renewable fuel.

Gas phase ion chemistry has fundamental and applicative purposes since it allows the study of the chemical processes in a solvent free environment and represents models for reactions occurring in the space at low and high temperatures. In this work the ion-molecule reaction of sulfur dioxide ion with carbon monoxide CO is investigated in a joint experimental and theoretical study. The reaction is a fast and exothermic chemical oxidation of CO into more stable CO2 by a metal free species, as , excited into ro-vibrational levels of the electronic ground state by synchrotron radiation. The results show that the reaction is hampered by the enhancement of internal energy of sulfur dioxide ion and the only ionic product is SO.+. The theoretical approach of variational transition state theory (VTST) based on density functional electronic structure calculations, shows an interesting and peculiar reaction dynamics of the interacting system along the reaction path. Two energy minima corresponding to [SO2–CO].+ and [OS–OCO].+ complexes are identified. These minima are separated by an intersystem crossing barrier which couples the bent 3B2 state of CO2 with C2v symmetry and the 1A1 state with linear D∞h symmetry. The spin and charge reorganization along the minimum energy path (MEP) are analyzed and eventually the charge and spin remain allocated to the SO.+ moiety and the stable CO2 molecule is easily produced. There is no bottleneck that slows down the reaction and the values of the rate coefficient k at different temperatures are calculated with capture theory. A value of 2.95 × 10−10 cm3s−1molecule−1 is obtained at 300 K in agreement with the literature experimental measurement of 3.00 × 10−10 ± 20% cm3s−1molecule−1, and a negative trend with temperature is predicted consistently with the experimental observations.