Browse Topic: Nitrogen oxides

Items (4,921)
With the rapid development of smart transport and green emission concepts, accurate monitoring and management of vehicle emissions have become the key to achieving low-carbon transport. This study focuses on NOx emissions from transport trucks, which have a significant impact on the environment, and establishes a predictive model for NOx emissions based on the random forest model using actual operational data collected by the remote monitoring platform.The results show that the NOx prediction using the random forest model has excellent performance, with an average R2 of 0.928 and an average MAE of 43.3, demonstrating high accuracy. According to China's National Pollutant Emission Standard, NOx emissions greater than 500 ppm are defined as high emissions. Based on this standard, this paper introduces logistic regression, k-nearest neighbor, support vector machine and random forest model to predict the accuracy of high-emission classification, and the random forest model has the best
Lin, YingxinLi, Tiezhu
Graphical Abstract Abstract The world is targeting zero-emission standards by promoting flexi-fuel-based vehicles. In the automotive industry, IC engine-powered vehicle has a good market. Either IC or flexi-fuel engines are considered the safest mode of transport, one tedious problem needs to be addressed is their toxic exhaust emissions from those engines. However, there are many aftertreatment systems available to control HC, CO2, NOx, and PM emissions. To control CO2 emissions there is no aftertreatment system available. Physical adsorbents such as activated carbon and zeolite are going to be used in this work to reduce emissions from exhaust gases. Zeolite has a greater affinity toward NOx emission, and activated carbon has greater potential to capture HC and carbon dioxide emissions. Initially computational studies were carried out to evaluate back pressure developed in adsorbent chamber. Analysis was carried out by varying conical length of the adsorbent chamber (68 mm, 75 mm
Subramanian, MohanKumarMuthiya, Solomon JenorisPachamuthu, SenthilkumarNaveena, B. E.Divya, G. S.Praveen Kumar, M. V.
With the continuous upgrading of emission regulations for internal combustion engines, the nitrogen oxide treatment capacity of selective catalytic reduction (SCR) aftertreatment needs to be continuously improved. In this study, based on a prototype of SCR aftertreatment, the impact of the arrangement of key components in the SCR system (urea injector, mixer, and catalyst unit) on ammonia uniformity was investigated. First, parameterized designs of the urea injector, mixer, and SCR unit were conducted. Then, using computational fluid dynamics (CFD), numerical simulations of the established aftertreatment system models with different parameter factors were performed under a high-exhaust temperature and a low-exhaust temperature conditions to study the impact of each individual parameter on ammonia uniformity. Finally, an optimized solution was designed based on the observed patterns, and the optimized samples were tested on an engine performance and emission test bench to compare their
Jie, WangJin, JianjiaoWu, Yifan
The primary issues in using pure vegetable oils for internal combustion engines are their high soot output and reduced thermal efficiency. Therefore in the present investigation, a Heavea Brasiliensis biodiesel (HBB) is used as a carbon source of fuel and ethoxy ethane as a combustion accelerator on a compression ignition (CI) engine. In this investigation, an only one cylinder, four-stroke, air-cooled DI diesel engine with a rated output of 4.4 kW at 1500 rpm was utilized. Whereas heavea brasiliensis biodiesel was delivered straightly into the cylinder at almost close to the end of compression stroke and ethoxy ethane was sprayed instantly in the intake manifold in the event of intake stroke. At various loads, the parameter of ethoxy ethane volume rate were optimised. To minimise exhaust emissions, an air plasma spray technology was employed to cover the engine combustion chamber with a thermal barrier coating. Because of its adaptability for high-temperature applications, YSZ (Yttria
Sagaya Raj, GnanaNatarajan, ManikandanPasupuleti, Thejasree
The rising demand for fossil fuels and the exploration of renewable energy sources from plants have gained significant attention due to their role in reducing emissions and enhancing energy security. Prosopis juliflora, abundantly available in India, offers a viable source for biodiesel production. This study investigates the performance and emission characteristics of a 5.2 kW, 1500 rpm, four-stroke single-cylinder compression ignition (CI) engine using blends of diesel, vegetable oil, and biodiesel derived from Prosopis juliflora seeds. The engine was tested with pure diesel, vegetable oil (PJO), biodiesel (B100), and biodiesel-diesel blends at 20%, 40%, 60%, and 80% by volume, designated as B20, B40, B60, and B80, respectively. Key performance metrics, including brake thermal efficiency (BTE) and brake specific energy consumption (BSEC), were measured, along with emissions such as carbon monoxide (CO), smoke, hydrocarbons (HC), and nitrogen oxides (NO). Results indicated that BTE
Duraisamy, BoopathiStanley Martin, JeromeThiyagarajan, PrakashRajendran, SilambarasanMarutholi, MubarakJohn, Godwin
The growing demand for fossil fuels and the search for alternatives have the potential to reduce emissions and enhance energy security. Karanja oil and tire pyrolysis oil (TPO) are identified as promising substitutes. This study examines the performance and emission characteristics of a 5.2 kW, 1500 rpm, four-stroke single-cylinder compression ignition engine. The engine was tested using diesel, the optimal combination of Karanja oil biodiesel (KOME) and TPO (50:50% volume ratio), and this KOME-TPO blend with hydrogen supplied in dual fuel mode at flow rates of 10 lpm, 20 lpm, and 30 lpm, designated as H10, H20, and H30, respectively. The results indicated that BTE for H30 was the highest, reaching 32.21% compared to 30.52% for diesel at 5.2 kW BP. BSEC for H30 was the lowest at 11.18 MJ/kWh, compared to 11.80 MJ/kWh for diesel at the same BP. Emission analysis showed that smoke and HC emissions were significantly lower for hydrogen-enriched blends. At 5.2 kW BP, HC emissions for H30
Duraisamy, BoopathiStanley Martin, JeromeChelladorai, PrabhuRajendran, SilambarasanMarutholi, MubarakMadheswaran, Dinesh Kumar
A diesel engine with a Yttria Stabilised Zirconium (YSZ) thermal barrier layer (TBL) on the piston crown was used in an experiment. The aim of the investigation was to evaluate the influence of the thermal barrier layer on the efficiency and pollution levels of a diesel engine. The selection of YSZ as the coating material was based on its desirable physical properties including a high coefficient of expansion when exposed to heat, low degree of thermal conductivity, and a high Poisson's number. These characteristics make it a suitable material for use in coatings applied to engine components. In addition to their current research, the scientists are also focusing on identifying sustainable substitutes for conventional petroleum fuels. This is because of the growing concern over environmental impacts and the limited availability of fossil fuel resources. The researchers are seeking new options that are both environmentally friendly and capable of meeting the world's energy demands. By
Sagaya Raj, GnanaNatarajan, ManikandanPasupuleti, Thejasree
Widely used as power equipment, diesel engines emit NO x , which significantly threatens the well-being of both the ecosystem and individuals. The SCR system, which is employed to reduce NO x emissions from diesel engines, relies on precise control of the NO x emission levels. Addressing the challenge that traditional NO x emission prediction methods struggle to accurately forecast the emissions under transient operating conditions, this article introduces a deep learning model that integrates CNN, ECA, and BIGRU. The model’s necessary experimental data were collected during the hot phase of the WHTC, and input parameters were screened through correlation analysis. The model employs a CNN for feature extraction, integrates an ECA module to refine key feature processing, and utilizes BIGRU to capture temporal dynamics and dependencies, yielding predictive outcomes. Additionally, the model employs the Adam optimizer and combines it with BWO to adjust hyperparameters, thereby elevating
Peng, YunlongWang, GuiyongWang, YuhuaWang, FeiyangWang, ZhiyuanHe, Shuchao
In the context of low-carbon and zero-carbon development strategies, the transformation and upgrading of the energy structure is an inevitable trend. As a renewable fuel, ammonia has a high energy density. When ammonia is burned alone, the combustion speed is slow. The emissions of nitrogen oxides and unburned ammonia is high. Therefore, a suitable high-reactivity combustion aid fuel is required to improve the combustion characteristics of ammonia. Based on this background, this study converted a six-cylinder engine into a single-cylinder ammonia/diesel dual-fuel system, with diesel fuel as the base and a certain percentage of ammonia blended in. The impact of varying the injection pressure and equivalence ratio on engine combustion and emissions was examined. The results demonstrate that an appropriate increase in injection pressure can promote fuel-gas mixing and increase the indicated thermal efficiency (ITE). With regard to emissions, an increase in injection pressure has been
Wang, HuLv, ZhijieZhang, ShouzhenWang, MingdaYang, RuiYao, Mingfa
Direct injection in the cylinder of a hydrogen internal combustion engine results in increasing NOx emissions in high-temperature oxygen rich environments. To explore the effect of excess air ratio λ on the NOx emissions of a direct injection hydrogen fueled internal combustion engine (HICE), a CFD simulation model was built based on a turbocharged direct injection hydrogen internal combustion engine using Converge software, and investigates the impact of lean burn on the NOx emissions. The simulation results show that increasing the excess air ratio λ can lower the in-cylinder mean temperature and effectively reduce the generation of NOx. The maximum temperature difference between λ=2.1 and λ=2.7 is 400K when engine speed is 4500 r/min. As the engine speed increases, under the same condition of λ, different loads at different speeds result in differences in the reaction temperature inside the cylinder, with higher temperatures at high speeds, so both the cylinder temperature and NOx
Peng, TianyuLuo, QingheTang, Hongyang
Lean NOx trap is a dedicated DeNOx catalyst for lean hybrid gasoline engines. Noble metals (usually platinum group metals) play the role of catalytic sites for NOx oxidation and reduction, which have significant impact of the performance of LNT. This work focuses on the influence of noble metal catalysts on self-inhibition effect from the view of competitive adsorption between NO and CO, and investigates the influence of CO self-inhibition effect on the main by-product of LNT: N2O formation. Adsorption configurations for NO, CO and N2O on noble metal clusters supported by γ-Al2O3(100) are confirmed. For detailed investigation, electron structures are analyzed by investigating Bader charge, DOS (density of state), charge density differences and COHP (crystal orbital Hamilton population) of selected configurations.The results show that CO self-inhibition effect is caused by competitive adsorption between CO and NO. The essence of competitive adsorption between CO and NO is that
Liu, MingliLiu, YaodongQu, HanshiDuan, JiaquanZhang, QiqiQian, DingchaoWang, ZhenxiHe, Zhentao
NOx after-treatment has greatly limited the development of lean-burn technology for gasoline engines. NH3-Selective Catalytic Reduction (SCR) technology has been successfully applied to NOx conversion in diesel engines. For gasoline engines, SCR catalyst is required to maintain high activity over a higher temperature window. In this study, we utilized a turbocharged and intercooled 2.0 L petrol engine to investigate the NOx conversion of two zeolite-based SCR catalysts, Cu-SSZ-13 and Fe/Cu-SSZ-13, at exhaust flows ranging from 80 to 300 kg/h and exhaust temperatures between 550 to 600°C. The catalysts were characterized using SEM, ICP, XRD, H2-TPR, NH3-TPD, and other methods. The selected Fe/Cu-SSZ-13 catalyst showed higher NOx conversion (>80%) in the temperature range of 550~600oC and 80~300 kg/h exhaust gas flow. NOx output could be controlled below 10ppm. The characterization results showed that although the specific surface area and acidic sites decreased after the aging treatment
Pan, ShiyiWang, RuwenZhang, NanXu, ZhiqinHu, JiangtaoLiao, XiukeDuan, PingpingChen, Ruilian
To advance the application of zero-carbon ammonia fuel, this paper presents an experimental investigation on the potential of ammonia substitution using a 2.0L ammonia-hydrogen engine, where ammonia is injected into the intake port and hydrogen is directly injected into the cylinder. The study examines the effects of ammonia substitution rate under various load conditions on engine combustion and emission performance. Results indicate that the maximum ammonia energy substitution rate reached 98%, and within the stable combustion boundary, the mass fraction of unburned ammonia was less than 3%. The ammonia energy substitution ratio increased with load, and ammonia addition significantly suppressed pre-ignition and knocking. As ammonia content increased, ignition timing advanced, combustion duration extended, ignition delay prolonged, COV increased, peak cylinder pressure, and pressure rise rate decreased, with a corresponding decrease in peak heat release rate. Compared to a pure
Wu, WeilongXie, FangxiChen, HongDu, JiakunLi, Yong
The use of carbon-neutral fuels instead of conventional fuels in gasoline direct injection (GDI) engines is beneficial to global decarbonization. However, the application of renewable non-petroleum fuels in GDI engines is still unclear due to their different physicochemical properties. Acetone-Butanol-Ethanol (ABE) is a promising low-carbon alternative fuel for GDI engines, but its high viscosity and latent heat cause pool firing during cold start. The existing flash boiling technology can solve this problem. This study explores the effects of flash boiling on spray characteristics, flame propagation, soot, and emissions of gasoline-ABE blend in a constant volume combustion chamber (CVCC) without airflow. Optical windows, high-speed camera recording, in-chamber pressure measurement, Fourier transform infrared spectroscopy (FTIR), and transmission electron microscope (TEM) were used to analyze flame spreading, combustion characteristics, exhaust gases, and soot morphology. Flash boiling
Nour, MohamedZhang, WeixuanCui, MingliLi, XuesongXu, MinQiu, Shuyi
This research investigates the development of a heat pipe heat exchanger coated with graphene for cooling and purification of automobile exhausts. The heat exchanger directly affects the performance of the engine because proper heat dissipation and transfer can improve engine performance, reduce fuel consumption, and decrease the emission. Moreover, this effect is much more noticeable on coated heat pipes because of the enhanced thermal conductivity and mechanical properties of the graphene films. A heat null emitted by internal combustion engines was used in the experimental setup to test the thermal performance, cooling efficiency, and purification efficiency of the newly designed in-house exhaust simulation system where the new heat pipes were inserted. The results of the experiment show that the heat pipes have very high thermal performance as the efficiency of the heat pipes was calculated to be around 85%. Furthermore, the temperature decrease over the surfaces of the heat
Karthigairajan, M.Seeniappan, KaliappanBalaji, N.Natrayan, L.Sheik, Salman BashaRavi, D.
Despite the increasing electrification of current vehicles, Diesel engines will continue to be used for several decades to come. There is still a need to introduce emission control technologies, especially those that show good potential and do not require extensive engine modifications. The increasing focus on reducing pollutant emissions and improving energy efficiency has prompted engine manufacturers to continuously strive for technological progress. The aim is to ensure compliance with environmental regulations and the fulfillment of social expectations. Specifically, new Diesel engine projects face the challenge of minimizing both nitrogen oxides (NOx) and soot emissions, which requires significant investiment in research to develop innovative combustion methods and exhaust gas treatment. One of these innovative methods is Ducted Fuel Injection (DFI), which aims to reduce emissions by improving spray development to obtain a better mixture at flame upstream. This study presents an
Dias, Fábio Jairodos Santos, Leila RibeiroRufino, CaioGarcia, Ezio CastejonLomonaco, RaphaelArgachoy, CelsoLacava, Pedro Teixeira
The current study investigates the influence of exhaust gas recirculation technique on the hydrogen (10lpm) inducted diesel engine using Cassia fistula derived biodiesel fuel. The focus is on evaluating the emission characteristics of the engine, with a particular emphasis on reducing NOx emissions. The study also examines the impact of varying the Exhaust Gas Recirculation (EGR) flow rate 10 and 20% on the aforementioned parameters. The novelty of this investigation lies in the comprehensive evaluation of emission metrics, particularly when combining Cassia fistula biodiesel with hydrogen induction. The experiment carried in Kirloskar TV1-V4A engine with blends consists 10%, 20%, 30% and 40% by volume of CFME blends with diesel. The inducted hydrogen at 10 lpm caused increased NOx which were discussed to suppress by EGR applications. Among the tested fuels, a blend containing 40% cassia fistula methyl ester (CFME) and 60% diesel (CFME40D60) showed the lowest hydrocarbon (HC) emissions
Veeraraghavan, SakthimuruganMadhu, S.De poures, Melvin VictorPalani, Kumaran
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