NH
-SCR (selective catalytic reduction) is important process for removal of NOx. However, water vapor included in exhaust gases critically inhibits the reaction in a low temperature range. Here, we ...report bulk W-substituted vanadium oxide catalysts for NH
-SCR at a low temperature (100-150 °C) and in the presence of water (~20 vol%). The 3.5 mol% W-substituted vanadium oxide shows >99% (dry) and ~93% (wet, 5-20 vol% water) NO conversion at 150 °C (250 ppm NO, 250 ppm NH
, 4% O
, SV = 40000 mL h
g
). Lewis acid sites of W-substituted vanadium oxide are converted to Brønsted acid sites under a wet condition while the distribution of Brønsted and Lewis acid sites does not change without tungsten. NH
species adsorbed on Brønsted acid sites react with NO accompanied by the reduction of V
sites at 150 °C. The high redox ability and reactivity of Brønsted acid sites are observed for bulk W-substituted vanadium oxide at a low temperature in the presence of water, and thus the catalytic cycle is less affected by water vapor.
•Energy and environmental issues have become of more and more concern worldwide.•Promising fuel components are introduced to increase engine performance.•An environmentally friendly motor gasoline is ...the recent trend to reduce emissions.
Engineers and researchers are dreaming of developing engines and fuels in such a way that very few harmful exhaust emissions can be generated and released to the environment without any significant environmental impact. This systematic review introduces five promising components for producing an environmentally friendly high-octane motor gasoline. Gasoline octane enhancers included bioethanol, prenol, furan mixtures, dimate, as well as isooctene (di-isobutylene). Insights between motor gasoline and engine performance were carried out by investigating these components in fundamental experiments. The results of studies demonstrated that these promising components have provided good synergetic chemical, physical, mechanical, and environmental characteristics when mixed with low-octane hydrocarbon fractions, including straight run hydrotreated naphtha, and hydrocracked naphtha. Moreover, the research and development (R&D) for each studied motor gasoline enhancers were proposed. Finally, the main problems, which whole world suffer from it are energy, environment, and water shortage. By using these motor gasoline components, two of the previous problems would be solved in terms of energy and environment.
In this experimental study, the usability of pyrolyzed tire oil (PRO) supplemented with motor silk (MS) as an alternative fuel for diesel engines was evaluated. For this purpose, PRO, euro diesel ...(ED) and MS were tried in a single cylinder engine by mixing in different proportions as standard diesel fuel (ED100), EPRO10 (10% PRO + 90% ED), EPRO20, EPRO30, EPRO10MS1 (1% MS + 99% EPRO10), EPRO20MS1 and EPRO30MS1 fuels with different loads (500, 750, 1000, 1250, 1500-Watt) and at constant engine speed (3600 rpm). With the data obtained from the experiments, engine performance and exhaust emission values were examined and compared. According to the results of the experiment, it was determined that the addition of 30% PRO into the ED increases the exhaust emissions and brake specific fuel consumption (BSFC) without any change in the engine fuel system. With the addition of MS, an average of 9% reduction was achieved in BSFC values in all fuels. In the case of working with EPROMS fuels, it has been determined that emissions of smoke, hydrocarbon (HC) and carbon monoxide (CO) are decreased, and nitrogen oxide (NOx) emissions are increased. Compared to the EPRO30 fuel, the EPRO30MS1 test fuel released an average of 23.561% less HC emission. The highest NOx emission value was determined as 285 ppm at 1500-W load with EPRO20MS1. According to the experimental results, it was observed that the use of MS increased the brake thermal efficiency (BTHE) values and decreased BSFC values. The increase in the BTHE values of EPRO10MS1 was found to be approximately 2.184% when the average of all loads was compared to the engine reference fuel (ED100).
•An improvement in emissions and performance was expected by adding urea and its mixtures to diesel fuel.•Engine performance deteriorated with Adblue, urea and urea + citric acid added to diesel ...fuel.•HC, CO, and NOx emissions decreased with diesel + urea + citric acid mixtures.•The addition of urea and its mixtures to diesel fuel increased fuel consumption.•Urea ratio effects should examine for engine performance and exhaust emissions.
Today, exhaust emissions have become a critical issue with the increasing number of vehicles due to greenhouse gas. Engine manufacturers carry out R&D studies due to emission limitations imposed on engines that use fossil fuels. Selective Catalytic Reactor and AdBlue injection systems have been used significantly to reduce NOx emissions in diesel engines. For this reason, AdBlue is sprayed in the exhaust manifold to reduce emissions with a second injector in diesel engines. In this study, the effects of commercial AdBlue, Urea-pure water mixture and urea- pure water-citric acid mixtures as additives to diesel fuel on exhaust emission and performance in a diesel single-cylinder engine were investigated. In-cylinder pressure, exhaust gas temperature, fuel consumption, air consumption and exhaust emissions were measured experimentally to examine the effects of 3 different mixtures added to diesel fuel at 8 different loads. As a result, urea-citric acid–water mixtures added to diesel fuel worsened combustion. Brake fuel specific consumption has increased 8% for diesel + urea + citric acid mixtures due to the presence of water in mixtures. CO2 emissions increased by 38% with the addition of AdBlue, while an increase of 53% was observed with the addition of diesel + urea + citric acid. With the addition of urea + citric acid to diesel fuel, CO emissions decreased by 233%, while under the same conditions, HC emissions decreased by 300% and NOx emissions decreased by a maximum of 19%.
Advances in engine technologies are placing additional demands on emission control catalysts, which must now perform at lower temperatures, but at the same time be robust enough to survive harsh ...conditions encountered in engine exhaust. In this Review, we explore some of the materials concepts that could revolutionize the technology of emission control systems. These include single-atom catalysts, two-dimensional materials, three-dimensional architectures, core@shell nanoparticles derived via atomic layer deposition and via colloidal synthesis methods, and microporous oxides. While these materials provide enhanced performance, they will need to overcome many challenges before they can be deployed for treating exhaust from cars and trucks. We assess the state of the art for catalysing reactions related to emission control and also consider radical breakthroughs that could potentially completely transform this field.Exhaust emissions catalysts can be used for the removal of harmful pollutants. This Review explores synthesis routes and materials for advanced catalysts, and identifies grand challenges for the transformation of pollutants.
Owing to the regulation of CO2 reduction in global transportation system, the number of vehicles using LPG is increasing worldwide and their cleanliness is being highlighted. LPG increases the ...content of propane (C3) to improve startability during winters; accordingly, the contents of butane (C4) and C3 change continuously depending on the weather. In this study, the spray and combustion process in an engine equipped with the latest LPLI system was analyzed to understand the engine control strategies according to the C3 content, and the change in exhaust emission was also studied. Although the injection quantity of LPG with C3 content of 25% was lower than that of LPG with 5% C3 content at the same fuel pressure, the commercial ECU increased the injection duration to match the number of carbons required for combustion. In addition, the ignition timing was advanced owing to the high-octane number of C3 and the maximum combustion pressure was increased by up to 8.63% owing to the high lower heating value and advanced ignition timing. In addition, BSNOx increased by up to 47.61% owing to the increased maximum combustion pressure, and BSCO and BSCO2 increased by 33.14% and 11.70%, respectively, due to excessive injection.
•Injection quantity of C3 25% LPG is below that of C3 5% LPG at same fuel pressure.•Injection quantity of C3 25% LPG is increased in the engine experiment to match the number of carbons.•Use of high-C3-content LPG increased the maximum combustion pressure.•BSNOx increased by up to 47.61% due to increase in maximum combustion pressure.•BSCO and BSCO2 increased by up to 33.14% and 11.70%, respectively.
•The initial spark kernel formation, growth and development were presented in the NG SI engine.•The relationship between exhaust emissions and mediate species was analyzed in the NG SI engine.•The ...methane oxidation process, intermediates species and reaction pathways were analyzed.•The energy balance of the NG SI engine fuelled with/without hydrogen were compared.
Technically, using hydrogen in the natural gas (NG) will increase the combustion rate of the spark ignition (SI) engine, particularly at the lean burn condition, which also benefits to improve the thermal efficiency and combustion efficiency. The aim of this study was to investigate the effect of hydrogen addition on the flame propagation, emissions formation, energy balance and the relationships between exhaust emissions and mediate species during the flame propagation in the natural gas (NG) SI engine. The 1D and 3D simulation models of the NG SI engine were built and validated against with experimental data. The results indicated that the initial spark kernel volume of the NG SI engine with hydrogen addition was larger than that of without hydrogen enriched. The NO concentration increased with the hydrogen due to its higher peak combustion temperature. The NO emission mainly generated inside the flame front, where located in the high temperature combustion zone. In addition, the CO formation rate of the NG SI engine with the hydrogen addition was faster and oxidized more completely. With adding hydrogen in natural gas, the amount of H and OH were significantly increased due to the chemical amplifiers, thereby enhancing the radical pool. The HC and soot emissions of the NG SI engine were much lower with the hydrogen addition. Furthermore, the energy efficiency and fuel economy of the NG SI engine were improved with the hydrogen addition, particularly at the lean mixture conditions.
The present research aims to study the impact of different gasoline additives and engine conditions on engine performance and combustion emissions. To this end, the experimental design and study with ...related modeling and optimization techniques are applied for appropriate and accurate evaluations and analysis. The D-optimal methodology is used to optimize engine power and exhaust emission through implementing the general blended fuel preparation and engine conditions considering the five main parameters, including choice of n-propanol loading percentage, type of nanoparticle materials, particle parentage in the blend, engine speed, and throttle. Findings by modeling analysis showed that the quadric and cubic terms of these five variables had significant and essential effects. The optimal conditions are obtained in blend of 8 wt% of n-propanol and 0.2 wt% of aluminum oxide (Al2O3), and engine speed and throttle of 1750 rpm and 26%, respectively. Under these conditions, the model estimated the CO, CO2, HC, and NOx emissions of 2.24, 5.09, 68.94, and 152.7 ppm, respectively. Employed experimental study, optimization procedure, and developed models can be used as a valuable technique for preparing modified gasoline fuels with effective performance.
•Novel and effective nano particles additives are introduced to add gasoline-n propanol blend.•D-optimal design and experimental study is performed to prepare propanol + MgO/Al2O3 and compare with gasoline.•Modeling and optimization of the response including emissions and engine performance are implemented.•Verification and accuracy analysis are performed for models.•additives result in higher engine performance and fuel combustion emissions efficiency than gasoline.
A road simulator was used to generate wear particles from the interaction between two tyre brands and a composite pavement. Particle size distributions were monitored using a scanning mobility ...particle sizer and an aerosol particle sizer. Continuous measurements of particle mass concentrations were also made. Collection of inhalable particles (PM10) was conducted using a high-volume sampler equipped with quartz filters, which were then analysed for organic and elemental carbon, organic constituents and elemental composition. Tyre fragments chopped into tiny chips were also subjected to detailed organic and elemental speciation. The number concentration was dominated by particles <0.5 μm, whereas most of the mass was found in particles >0.5 μm. The emission factor from wear between pavements and tyres was of the order of 2 mg km−1 veh−1. Organic carbon represented about 10% of the PM10 mass, encompassing multiple aliphatic compounds (n-alkanes, alkenes, hopanes, and steranes), PAHs, thiazols, n-alkanols, polyols, some fragrant compounds, sugars, triterpenoids, sterols, phenolic constituents, phthalate plasticisers and several types of acids, among others. The relationship between airborne particulate organic constituents and organic matter in tyre debris is discussed. The detection of compounds that have been extensively used as biomass burning tracers (e.g. retene, dehydroabietic acid and levoglucosan) in both the shredded tiny tyre chips and the wear particles from the interaction between tyres and pavement puts into question their uniqueness as markers of wood combustion. Trace and major elements accounted for about 5% of the mass of the tyre fragments but represented 15–18% of the PM10 from wear, denoting the contribution of mineral elements from the pavement. Sulphur and zinc were abundant constituents in all samples.
•A road simulator was used to generate wear particles from pavement/tyre interaction.•PM10 emission factors were around 2 mg km−1 veh−1.•Organic carbon represented about 10% of the PM10 mass.•Elements accounted for ~5% of the shredded tyre chips and to 15–18% of the PM10 mass.•Biomass burning tracers were present in the shredded tyre chips and in PM10 from wear.
In this research, effects of hydrogen addition on a diesel engine were investigated in terms of engine performance and emissions for four cylinders, water cooled diesel engine. Hydrogen was added ...through the intake port of the diesel engine. Hydrogen effects on the diesel engine were investigated with different amount (0.20, 0.40, 0.60 and 0.80 lpm) at different engine load (20%, 40%, 60%, 80% and 100% load) and the constant speed, 1800 rpm. When hydrogen amount is increased for all engine loads, it is observed an increase in brake specific fuel consumption and brake thermal efficiency due to mixture formation and higher flame speed of hydrogen gas according to the results. For the 0.80 lpm hydrogen addition, exhaust temperature and NOx increased at higher loads. CO, UHC and SOOT emissions significantly decreased for hydrogen gas as additional fuel at all loads. In this study, higher decrease on SOOT emissions (up to 0.80lpm) was obtained. In addition, for 0.80 lpm hydrogen addition, the dramatic increase in NOx emissions was observed.
•A hydrogen combustion analysis has been performed in CI engine experimentally.•Combustion characteristics of hydrogen added CI engine has been analyzed.•Emission characteristics of hydrogen added CI engine has been analyzed.
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