Browse Topic: Emissions control

Items (7,018)
Platinum (Pt), palladium (Pd), and rhodium (Rh) are used as active substances in exhaust gas purification catalysts for automobiles. Among these, Rh is an essential element because it efficiently promotes a NOx reduction reaction. On the other hand, the price of Rh has been rising in recent years. From the perspective of the supply risk of rare resources, there is an urgent need to develop technologies to replace or reduce the amount of Rh used in catalysts. We focused on the pseudo-rhodium alloy developed by the ACCEL program of the Japan Science and Technology Agency (JST), and then investigated the application of the pseudo-rhodium alloy on the catalysts of our motorcycles and also the degradation process. A nanosized PdRuIr alloy supported on a ceria-zirconia solid solution (PdRuIr/CZ) was prepared and assembled into a motorcycle for emissions measurement. The PdRuIr/CZ catalyst with an alloy loading of 4.0 g/L had initial properties comparable to the Rh supported on a CZ (Rh/CZ
Motegi, TakuyaTatara, ShunyaTakamoto, ShunpeiDoi, Kosuke
This study proposes a technique to predict the catalytic activity of the CO-NO-O2 reaction using the first principle calculations without experiment. The proposed method consists of four steps. (1) Assuming the detailed chemical reactions based on the Langmuir-Hinshelwood mechanism. (2) Estimating the activation energy (Ea) for each detailed chemical reaction using first principle (e.g. Density Functional Theory: DFT) calculations. (3) Defining frequency factors (A) theoretically. (4) Inputting the estimated Ea and A values into simulation software for chemical-kinetics (e.g. exothermia suite) and running the simulation. The validity of the proposed method was evaluated by experiments. This study predicted the catalytic activities of Pt, Pd or Rh(111) surfaces. The predicted results qualitatively matched the experimental outcomes obtained from the Pt, Pd or Rh thin-film catalyst prepared by the “arc plasma method”.
Miura, KazuyaKusaba, HirokiMiyoshi, TomoyaYoshida, HiroshiTsuchizaki, HiroyukiMachida, Masato
Selective catalytic oxidation/reduction catalysts coated on diesel particulate filters (SDPF) are an important technology route to meet next-stage emission regulations. The previous research of the research group showed that compared with SDPF coated with Cu-SSZ-13, the SDPF coated with novel selective catalytic oxidation-selective catalytic reduction (SCO-SCR) catalyst, which combined MnO2-CeO2/Al2O3 and Cu-SSZ-13, can simultaneously improve NOx reduction and soot oxidation performance. Catalyst coating strategy is an important parameter affecting the performance of SDPF. In this study, the effects of different coating strategies of SCO-SCR catalysts (C25, C50, C75, and C100) on the performance of NOx reduction and soot oxidation in SDPF were investigated. The results show that, as the inlet gas temperature increases, NO emissions first decrease and then increase, NOx conversion efficiency first increases and then decreases, and the rich-NO2 area, NH3 oxidation rate, N2O, CO, CO2
Chen, Ying-jieTan, PiqiangYao, ChaojieLou, DimingHu, ZhiyuanYang, Wenming
This paper presents recent developments of the Euler/Lagrange wall film model which allow the efficient simulation of complete Selective Catalytic Reduction (SCR) systems, used for exhaust gas aftertreatment in diesel and newly designed H2 engines. Since release 2024R2, ANSYS Fluent is equipped with a chemistry model from recent literature to predict homogeneous chemical reactions in the film and heterogeneous reactions between gas and film occurring in SCR systems operating with aqueous urea solutions. The implementation of the chemistry model is first validated against results from Thermo–Gravimetric Analysis (TGA) measurements. The SCR–specific chemistry, combined with the Lagrangian Wall Film (LWF) model employing an improved wall–film convective heat transfer model, is then compared favorably with experimental SCR test rig measurements of urea deposits for fifty injection cycles, followed by a relaxation period. The full simulation completes significantly faster due to a new
Sofialidis, DimitriosMutyal, JayeshFaltsi, RanaBraun, MarkusBörnhorst, MarionEsch, Thomas
Minimizing the time needed to achieve light-off temperatures in diesel engine aftertreatment devices is key to mitigate pollutant emissions during the first minutes of operation. Catalyst heating operation typically includes one or multiple post-injections late during the expansion stroke aimed to increase the enthalpy of the exhaust gases. However, post-injection retardability is constrained by low combustion efficiency and the formation of CO and unburned hydrocarbons that cannot be oxidized by a still-inactive oxidation catalyst. In this study, the effects of post-injection strategy on the performance and emissions of a medium duty diesel engine have been investigated experimentally, focusing on the impacts on post-injection retardability. A five injection strategy (two pilot, one main, two post) was implemented in the engine, and the injection duration ratio between the two post-injections has been varied systematically while performing post-injection timing sweeps to identify the
Lopez Pintor, DarioLee, SangukCho, SeokwonBusch, StephenWu, AngelaNarayanan, AbhinandhanAbboud, Rami
On-board diagnosis (OBD) of gasoline vehicle emissions is detected by measuring the fluctuations of the rear oxygen sensor due to the time-dependent deterioration of the oxygen storage capacity (OSC) contained in the automotive catalyst materials. To detect OBD in various driving modes of automobiles with an order of magnitude higher accuracy than before, it is essential to understand the OSC mechanism based on fundamental science. In this study, time-resolved dispersive X-ray absorption fine structure (DXAFS) using synchrotron radiation was used to carry out a detailed analysis not only of the OSC of ceria-based complex oxides, which had previously been roughly understood, but also of how differences in design parameters such as the type of precious metals, reducing gases (CO and H2), detection temperatures, and mileages (degree of deteriorations) affect the OSC rate in a fluctuating redox atmosphere. A fundamental characteristic was clearly demonstrated in ceria-based complex oxides
Tanaka, HirohisaMatsumura, DaijuUegaki, ShinyaHamada, ShotaAotani, TakuroKamezawa, SaekaNakamoto, MasamiAsai, ShingoMizuno, TomohisaTakamura, RikuGoto, Takashi
In order to comply with the tightening of global regulations on automobile exhaust gas, further improvements to exhaust gas control catalysts and upgrades to on-board diagnostics (OBD) systems must be made. Currently, oxygen storage capacity (OSC) is monitored by front and rear sensors before and after the catalyst, and deterioration is judged by a decrease in OSC, but it is possible that catalyst deterioration may cause the rear sensor to detect gas that has not been sufficiently purified. It is important to observe the activity changes when the catalyst deteriorates in more detail and to gain a deeper understanding of the catalyst mechanism in order to create guidelines for future catalyst development. In this study, we used a μ-TG (micro thermogravimetric balance) to analyze in detail how differences in design parameters such as the type of precious metal, detection temperature, and mileage (degree of deterioration) affect the OSC rate in addition to the OSC of the ceria-based
Hamada, ShotaUegaki, ShinyaTanabe, HidetakaNakayama, TomohitoJinjo, ItsukiKurono, SeitaOishi, ShunsukeNarita, KeiichiOnishi, TetsuroYasuda, KazuyaMatsumura, DaijuTanaka, Hirohisa
The pollutant emission regulation for Non-Road Mobile Machinery (NRMM) is currently under consideration, both in the European Union (EU) and the United States (US). In Europe a Stage V review is expected within 2025 and in the US, the California Air Resource Board (CARB) has released their Tier 5 proposal in late 2024. It is expected that there will be further focus on covering a wide variety of operation conditions in actual use cases, including continuous low load scenarios. In addition, CO2-neutral fuels are being investigated to reduce the carbon footprint of NRMM Internal Combustion Engines (ICE), which remains an important powertrain for the sector. The objective of the work presented is to assess the potential for emissions reductions in the future, both NOx and CO2. A simulation study is conducted, modelling a 9l class engine with 8-10 g/kWh engine-out NOx emission level. Three different emission control systems are investigated: an enhanced stage V system with single SCR, a
Demuynck, JoachimBosteels, DirkMichelitsch, PhilippNoll, Hannes
The integration of low-octane gasoline with a compression ignition combustion system has been proposed as a strategy to reduce Well-to-Wheel CO2 emissions from automobiles using petroleum-based fuel. In the current situation where low-octane gasoline is not widely available in the market, onboard reforming of commercial gasoline to increase the cetane number (lower the octane number) allows for compression ignition combustion even with commercial gasoline. This requires “Cetane on Demand” technology, which enables compression ignition combustion with both commercial gasoline and low-octane gasoline. It is known that the ignition property of fuel is enhanced when the fuel is oxidized to generate hydroperoxides. Moreover, the use of N-hydroxyphthalimide (NHPI) as a catalyst promotes hydroperoxide generation at low temperatures. The objective of this study is to develop a device that enhances the ignition properties of gasoline through onboard fuel reforming. Initially, from the seven
Hashimoto, KohtaroYamada, YoshikazuMatsuura, KatsuyaKudo, TomohideChishima, HiroshiAl-Taher, MaryamKalamaras, ChristosAlbashrawi, Reem
The upcoming EURO 7 and EPA Tier 4 regulations and the possible China 7 are expected to tighten the tailpipe particulate emissions limits significantly. High performance Gasoline Particulate Filters (GPFs) with high filtration efficiency and low pressure drop would be mandated for gasoline engines to meet these stringent regulations. Due to packaging constraints, GPFs are often coated with three-way catalyst (TWC) materials to achieve four-way functionality. Ash accumulation in GPFs also has a significant impact on the performance of GPFs. This paper utilizes 3D CFD to predict the transient filtration efficiency and pressure drop of a washcoated GPF with ash accumulation during the soot loading process. Simulation results show a decent match with experimental data. The 3D CFD model also provides detailed information on soot penetration in the GPF wall substrate and soot cake characteristics on the wall. These information can be crucial for GPF wall substrate design and washcoating
Yang, PengzeCheng, Zhen
Three-way catalysts (TWCs) containing significant amounts of precious metals are commonly employed to purify exhaust emissions (CO, NOx, and THC) from gasoline-powered vehicles. A critical factor contributing to TWC degradation is the sintering of these precious metals. Maintaining the appropriate particle size and distribution of the metals is essential for optimal catalyst performance. In this study, palladium (Pd) nanoparticles with a uniform size were synthesized using ethylene glycol as a reductant under ultrasonic conditions, yielding particles in the range of 3 nm to 5 nm. These Pd nanoparticles were subsequently used to prepare three-way catalysts on cordierite substrates supplied by Corning (China) Inc. Chemisorption analysis revealed that the Pd active component in the catalysts prepared via the ultrasonic method exhibited higher dispersion than the state-of-the-art commercial catalysts. The aged catalysts were obtained after 150 hours of aging following the General Motors
Hao, ShijieLv, YananWang, WeidongRao, ChaoWei, WeiMao, BingbinChen, TaoZhao, Huawang
Renewable and alternative liquid fuels are being evaluated for their equivalence with ultra-low sulfur diesel (ULSD) in terms of engine and emission control system performance. Our previous research showed an elevated lightoff temperature for diesel oxidation catalyst (DOC) and lower DOC thermal efficiency for biodiesel blends into ULSD with more than 20% biodiesel. Here we report a similar DOC performance study to gage the performance of blends of biodiesel and hydrocarbon renewable diesel (RD) also made from fats and oils feedstocks. The same DOC used previously was used to evaluate RD blends with biodiesel up to 60 vol% (B60R40) in decrements of 10%. The performance of the DOC was evaluated on a steady-state performance cycle and a transient lightoff curve. Similar to previous results, the performance of the DOC is significantly affected by even low blend levels of biodiesel. At low flow rates 50% (B50R50) and higher biodiesel blends have a poor performance defined as the lightoff
Lakkireddy, VenkataWeber, PhillipMcCormick, RobertHowell, Steve
Measurements of Hydrogen emissions from vehicle exhaust have been often substituted for prediction models, partly due to the lack of Hydrogen analyzers targeted for combustion gases. A previous study using a Hydrogen mass spectrometer revealed that the ratio of Hydrocarbons entering a Three-Way Catalyst (TWC) and Hydrogen leaving the catalyst was inconstant throughout a standardized driving cycle. Although Hydrogen by itself is not currently a target of emission regulations, its omission during catalyzer optimization may disrupt the intended performance of the integrated aftertreatment system. The highest emissions of unwanted gases are commonly seen during vehicle cold start. Thus, this study focuses on intermittent operation of an engine, such as that of full hybrid vehicles. In particular, this study measures how the gases trapped in the aftertreatment system continue to react over the TWC as it cools down after the engine stops. Hydrocarbons, NOx, NH3 and H2 are measured before and
Lamas, Jorge EduardoLacdan, Ma CamilleHara, KenjiOtsuki, Yoshinori
China 6b regulation was fully implemented since July 2023 with very strict emission standards for HC, NMHC, NOx, and CO. The country is now also in the process of developing China 7 regulation, which will perhaps impose even stricter emission limits and extra criteria pollutants including NH3. Moreover, increasingly strict fuel consumption regulation has been implemented as well and it is highly possible that greenhouse gas emission limits will be included in the China 7 regulation. With the hybrid technology innovation, PHEVs are effective in fuel economy and emission reduction, which are favored by manufacturers and consumers, and leading to a rapid increase in market share. Through the optimization of hybrid architecture and the synergy of electric motors, the operating conditions of the hybrid engine have been optimized, making it more stable and avoiding extreme engine operating conditions compared to traditional ICE, which also provides possibilities for optimizing the after
Wang, JimingLi, ChunboFeng, XiangyuChen, XiaolangBoger, ThorstenTian, LichenHu, XianliZeng, JunTian, TianGao, BojunLi, DachengLiu, ShichengJiang, Fajun
Nowadays, hydrogen (H2) is rising as a key solution to fuel internal combustion engines (ICE) since it allows carbon free combustion process. At the same time, ICE fueled with H2 can reach similar performance and driving experience of gasoline fueled ones. In stoichiometric conditions, hydrogen shows higher flame speed, lower ignition energy and lower quenching distance than gasoline. Mainly for these reasons, H2 combustion is characterized by a high risk of abnormal combustion (i.e. knock and pre-ignition), relevant NOx emissions and high heat losses. On the other hand, the wide flammability range and high combustion stability of H2 allow the use of different techniques to reduce combustion reactivity. This work presents a combined approach, experimental and numerical, to assess the benefits of three mixture dilution methods. The experimental campaign, in different operating conditions, was carried out on a production derived high specific power gasoline Single Cylinder Engine (SCE
Tonelli, RobertoMedda, MassimoGullino, FabrizioSilvestri, NicolaZaffino, FrancescoMariconti, RobertoRossi, Vincenzo
Exhaust gas regulations, such as Tier4, Euro7, and China7, are being strengthened. In addition to the regulated values during specified driving patterns, emissions must be minimized under various usage scenarios. Since vehicle catalysts have been using higher amounts of precious metals to satisfy these requirements, there is increasing demand to decrease the usage of these metals from the perspective of environmental protection. The exhaust gas emission is divided into cold emission and hot emission. Recently, improvements of cold emission have become a focus. This research focused on improving catalyst warm-up activity by positioning the palladium (Pd) layer above the rhodium (Rh) layer. At the same time, to resolve the decrease in gas utilization in the Rh layer, connectivity was enhanced, and the influence of sulfur components was suppressed through the optimization of the Pd support. As a result, the usage of precious metals has successfully lowered.
Nishio, TakahiroTakagi, NobuyukiTojo, TakumiFujita, NaotoMori, MizuhoToda, Yosuke
This is a follow-up paper to the two previous reports [1, 2] regarding the development of a zeolite-based, hydrocarbon (HC) trap-type cold-start catalyst (CSC) as a method to meet future vehicle tailpipe emission standards. In this paper, vehicle tests at a low ambient temperature of -7°C have been performed and the CSC has been shown to further decrease the tailpipe cold start non-methane hydrocarbon (NMHC) emissions by 59% when compared to a standard 23°C WLTC test. This work has proven that the increased presence of condensed water at low ambient temperatures within the exhaust system does not affect the ability to provide a NMHC reduction, in fact the lower ambient temperature enables an increase in the reduction capability due to the ability to retain and then release the stored NMHC in a more controlled manner. Additionally, the impact of the zeolite loading level was investigated and the high zeolite loading within a CSC did improve the cold-start NMHC but the benefits did
Xu, LifengZhao, FuchengWei, HongZhao, PengfeiZhao, JiajiaMa, RuiboNewman, PhilipWang, LinQian, WangmuQian, Menghan
Alpha Engineered Composites’ thin profile textile composite heat shields provide thermal protection through several thermodynamic mechanisms including: radiation reflection; heat spreading; and finally heat transfer resistance. Typical under the hood automotive applications require heat shield average operational temperature up to 225°C, but newer internal combustion engines are being designed for higher operational temperatures to: increase efficiency through higher compression cycle ratios and lean burning; boost power through turbocharging; increase energy density; and support advanced emissions controls like EGR that can increase average operational temperature up to 300°C. Unfortunately, thermo-oxidative degradation mechanisms negatively impact the polymer structural adhesive within a heat shield textile composite and degrade thermal protection mechanisms. High average operational temperature degradation of traditional versus next generation textile composite heat shields is
Vazquez, Mark
Prior study with biodiesel and its blends with ultra-low sulfur diesel (ULSD) and renewable diesel (RD) showed that a commercial diesel oxidation catalyst (DOC) is unable to effectively oxidize neat biodiesel (B100) or high-level biodiesel blends injected into the exhaust of a diesel engine at challenging conditions of low temperature, high exhaust flow rate and high dosing rate. In steady-state performance tests, the performance of blends up to B50 in ULSD or RD was nearly equivalent to ULSD at the lowest exhaust flow rate or for exhaust temperature over 340°C for medium and high flows. ULSD blends above 50 vol% biodiesel exhibited reduced thermal efficiency and DOC outlet temperature with increasing dosing rate and required exhaust temperatures over 400°C to achieve similar performance as ULSD. For RD blends at higher flow rates and temperatures below 300°C even B10 blends showed some loss in performance at the highest dosing rates. Data showed an increase in lightoff temperature
Lakkireddy, VenkataWeber, PhillipMcCormick, RobertHowell, Steve
A reemergence of manufacturer interest in range-extended electric vehicles is being driven by increasing diversification of consumer interest in low carbon-intensity technologies in the passenger vehicle and other markets. A major advantage of range-extended electric vehicles is that they curtail consumer vehicle range anxiety while maintaining a lower vehicle cost when compared with battery electric vehicles (BEV). By incorporating a small liquid-fueled internal combustion engine (ICE), the range and “refueling” time of electrified vehicles can be significantly improved while overcoming issues with cost and weight faced by long-range battery packs. Compared to ICEs designed for non-hybrid and mild hybrid vehicles, the ICE in a range-extended electric vehicle has a unique set of requirements focused on compact size, low cost, and efficient operation within a limited engine map. A Range Extender (REx) 0.9L 2-cylinder engine was selected which prioritizes these attributes in a
Peters, NathanMarion, JoshuaPothuraju Subramanyam, SaiHoth, AlexanderBunce, Mike
With the increasing clarity of the CNVII emission legislation, it is foreseeable that CNVII will further tighten the emission limits of major pollutants such as Nitrogen Oxide (NOx), Nitrous Oxide (N2O) and Particulate Number (PN). Together with the implementation of stage IV fuel consumption legislation in July 2025, which requires engine fuel consumption reduction or thermal efficiency improvement, it will lead to further deterioration of its pollutant emissions and reduction of exhaust temperature, posing greater challenges to the After-Treatment System (ATS) in terms of NOx removal, particularly during engine cold start and N2O formation suppression. This study is an extension of our earlier investigation [1], and a novel copper-based corrugated SCR (Full Body-CuSCR, FB-CuSCR) technology was successfully applied. The results based on a modified CNVI medium duty engine indicated excellent dynamic response of the FB-CuSCR technology over cordierite which helped to improve the
Wang, YanFu, GuangxiaChen, ShuyueAberg, AndreasJiang, ShuiyanZhang, Jun
Under the background of the global dual carbon target, ammonia and hydrogen as the carbon-free fuel, have become a research hotspot for internal combustion engines. The existing researches mainly focus on the combustion characteristics influenced by equivalence ratio, hydrogen jet ignition and so on, while the relationship between combustion and emission characteristics should be also paid more attention. In this paper, the impact of combustion characteristic parameters on engine emissions is investigated by GT-power. The simulation model is based on a single cylinder engine with an active pre-chamber. Meanwhile, combustion characteristic parameters, in terms of CA50, combustion duration, CA10-CA50 and CA50-CA90 are set referred to the research of hydrogen jet ignition ammonia-hydrogen internal combustion engines. The results shown that there is compelling correlation between combustion parameters and specific emission profiles in ammonia-hydrogen internal combustion engines. Notably
Yuan, YangShang, QuanboDeng, JunLi, LiguangYin, XuemeiLai, HuilongMa, JiangliYu, FeiFeng, FengCui, HaoDu, Junchen
In hydrogen-fueled internal combustion engine (H2ICE), there are some ways to reduce nitrogen oxides (NOx) emissions. Using the wide flammability range of hydrogen, such as conducting lean combustion to reduce nitrogen oxides and employing exhaust gas recirculation (EGR), have been adopted. However, challenges exist in terms of load expansion, and due to the absence of high heat capacity of carbon dioxides in the exhaust, EGR also struggles to exhibit significant effects. In such a scenario, there is growing interest in injecting water into the H2ICE as an alternative to augment the EGR effect. In this study, the spark ignition (SI) single-cylinder engine equipped with two direct injectors was used to evaluate the hydrogen and the water dual direct injection combustion system. This system involved the direct injection of hydrogen using a wall-guided gasoline direct injector and the direct injection of water into the combustion chamber using a diesel injector. This approach utilizes the
Kim, KiyeonLee, SeungilKim, SeungjaeLee, SeunghyunMin, KyoungdougOh, SechulSon, JongyoonLee, Jeongwoo
Pre-chamber combustion is an advanced ignition strategy that has been shown to enhance spark ignition (SI) combustion stability in natural gas (NG) engines by providing distributed ignition sites from turbulent jets and enhancing main-chamber turbulence. Pre-chamber combustion has been proven especially advantageous compared to SI in ultra-lean and dilute operating conditions. This work involves experimental investigation of the effects of varying passive pre-chamber nozzle configuration on pre-chamber and main chamber combustion under simulated exhaust gas recirculation (EGR) dilution (0 and 20%) conditions in a heavy-duty, single-cylinder, optically accessible NG engine at stoichiometric fuel-air ratio. Pre-chamber nozzle configurations include four pre-chambers with constant nozzle area to pre-chamber volume ratio (A/V) with different nozzle sizes and orientations and one configuration with larger nozzles. The optical engine is operated in a skip-fire sequence consisting of 18
Dhotre, AkashNyrenstedt, GustavRajasegar, RajavasanthVarma, ArunSingh, SatbirNorthrop, WilliamSrna, Ales
Transient operation of a diesel-fueled compression ignition engine will produce significant levels of engine-out criteria pollutants such as NOx and soot emissions due to turbocharger lag. Conventional pollutant mitigation strategies during tip-ins (large increases in load) are constrained by the soot–NOx trade-off—strategies that mitigate soot/NOx emissions often result in an increase in NOx/soot emissions. Hybridization offers the ability to use an e-machine as an energy buffer during a tip-in, allowing the engine to tip-in slower to give the turbocharger time to spin up and provide the necessary amount of air for clean, high-load operation. In this work, an in-line six-cylinder 12.8 L Detroit Diesel DD13 engine was used to study the impact of slowing the torque ramp rate of a tip-in on the effectiveness of transient emission reduction strategies for turbocharged diesel engines, including exhaust gas recirculation (EGR) valve closing, start of injection retard, and the air–fuel ratio
Gainey, BrianDatar, AdityaBhatt, AnkurLawler, Benjamin
The growing number of automobiles on the road has raised awareness about environmental sustainability and transportation alternatives, sparking ideas about future transportation. Few short-term alternatives meet consumer needs and enable mass production. Because they do not accurately reflect real-world driving. Current models are unable to estimate vehicle emissions. However, the purpose of this research is to present an application of an adaptive neuro-fuzzy inference system for managing the various factors contributing to vehicle gasoline engine exhaust emissions. It examines how well the three known standardized driving cycles (DSCs). Accurately reflect real-world driving and evaluate the impact of real-world driving on vehicle emissions. Indirect emissions are inversely proportional to the vehicle’s fuel consumption. The methodology used is Eco-score methodology to calculate indirect emissions of light vehicles. Expected emission charge estimates for different using styles
Shiba, Mohamed S.Abouel-Seoud, Shawki A.Aboelsoud, W.Abdallah, Ahmed S.
Active fuel injection into a pre-chamber (PC) promotes high-temperature and highly turbulent jets, which ignite the cylinder gas with a very high exhaust gas recirculation (EGR) ratio, reducing emissions such as NOx. In the present study, two active PC injection strategies were designed to investigate the effect of injected hydrogen mass and PC mixture air-to-fuel equivalence ratio λ on PC combustion, jet formation, and main chamber (MC) combustion. Stoichiometric or rich hydrogen/oxygen mixtures are actively injected into the PC to enhance the combustion processes in the PC and the MC. A three-dimensional numerical engine model is developed using the commercial CFD code CONVERGE. The engine geometry and parameters adopt a modified GM 4-cylinder 2.0 L GDI gasoline engine. The local developments of gas temperature and velocity are resolved with the adaptive mesh refinement (AMR). The turbulence of the flow is computed with the k-epsilon model of the Reynolds-averaged Navier–Stokes (RANS
Yu, TianxiaoLee, Dong EunAlam, AfaqueGore, Jay P.Qiao, Li
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
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
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
Due to the vibration of the vehicle, the performance of the vehicle carbon canisters will be changed, which will affect its control effect on the fuel evaporation emission. In this study, a vibration test platform capable of simulating vehicle vibration characteristics was used to simulate the possible vibration effects of the vehicle carbon canisters, and to analyze the absorption and desorption performance of the carbon canisters before and after long-term operation and its influence on vehicle evaporation emissions. The results show that the carbon canisters will precipitate the carbon powder after the continuous action of the forward and backward vibration of the vehicle. As a result, the ultimate adsorption and desorption amount of fuel vapor decreased, and the adsorption amount decreased more obviously. In the 48-hour Diurnal Breathing Loss (DBL) test, fuel vapor diffusion is more difficult due to the increased flow resistance of the carbon canisters after vibration, and fuel
Yu, XiaohongLiu, YiyaoFeng, YifangZheng, YushuoChen, TaoZhao, Hua
A 20-cell self-humidifying fuel cell stack containing two types of MEAs was assembled and aged by a 1000-hour durability test. To rapidly and effectively analyze the primary degradation, the polarization change curve is introduced. As the different failure modes have a unique spectrum in the polarization change curve, it can be regarded as the fingerprint of a special degradation mode for repaid analysis. By means of this method, the main failure mode of two-type MEAs was clearly distinguished: one was attributed to the pinhole formation at the hydrogen outlet, and another was caused by catalyst degradation only, as verified by infrared imaging. The two distinct degradation phases were also classified: (i)conditioning phase, featuring with high decay rate, caused by repaid ECSA change from particle size growth of catalyst. (ii) performance phase with minor voltage loss at long test duration, but with RH cycling behind, as in MEA1. Then, an effective H2-pumping recovery is conducted
Pan, ChenbingWu, HailongRuyi, Wang
To explore the heat and mass transfer processes within the low-temperature catalyst layer, a coupled heat and mass transfer lattice Boltzmann model and electrochemical model were established, creating a pore-scale model for heat and mass transfer in the catalyst layer. The influence of the catalyst layer parameters was investigated. The results indicate that as time progresses, heat gradually accumulates at the top of the catalyst layer (CL) and is transmitted towards the bottom. Once oxygen enters the CL, it quickly fills the pores within the CL, resulting in a rapid decrease in oxygen concentration within the ionomer. As the platinum volume fraction increases, there is a significant rise in temperature across the entire calculation domain. With the increasing platinum volume fraction, the current density also increases rapidly due to the larger reaction area. When the carbon volume fraction is 0.15, more oxygen enters the ionomer to participate in reactions, and the large porosity
Xu, ShengChen, XinSheng, Tao
In the existing evaporation emission control and monitoring system, it is still necessary to popularize and develop more suitable evaporation emission monitoring, diagnosis and control methods. This study developed a design for the control system of evaporative emissions in hybrid vehicles, focusing on monitoring and controlling fuel evaporative emissions. A fuel evaporation model for automotive fuel tank was established. In this study, the key component of vehicle evaporative emission system, the fuel tank, is modeled and simulated. Through 6-hour and 12-hour experimental studies on fuel evaporation characteristics inside the tank, measurements were taken to determine the amount of evaporation under different liquid levels, temperatures, and vibration states. When the temperature increased from 12°C to 17°C and then further to 28°C, the rate of fuel evaporation increased by 25% and 50%, respectively. The increase in temperature significantly enhanced the rate of evaporation. A
Zheng, YushuoYu, XiaohongYao, ZhuoxiaoFeng, YifangLi, ZhijunChen, Tao
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
The integration of phase change materials (PCMs) with thermoelectric generators (TEGs) presents a solution to the challenge of unstable output resulting from fluctuations in the heat source. This study involved the establishment of an experimental test setup for PCM-TEG system to examine the impact of heat source power on the thermoelectric performance of PCM-TEG system. The results suggest that incorporating PCM effectively mitigates output voltage fluctuations, while higher heating power levels correspond to a notable extension in effective operational duration. In situations of low heat source power, incomplete PCM melting may lead to a significant decline in electricity generation during non-heating stages. Notably, the electricity generation during non-heating stages at 90 W heating power surpasses that at 30 W heating power by a factor of 11.78. Furthermore, the electricity generated during non-heating stages contributes to 22.4% of the total electricity generation. These
Tian, MengWu, FengyuZuo, AoXuan, ZhiweiZhao, Yulong
Letter from the Focus Issue Editors
Lakhlani, HardikKumar, VivekWenbin, YuBagga, KalyanGundlapally, SanthoshDi Blasio, GabrieleSplitter, DerekRajendran, Silambarasan
Throughout the years, the legislations which drive the vehicle development have experimented constant evolutions. Especially when it comes about pollutant emissions and NVH ( Noise, Vibration & Harshness). However, it is complex to understand which calibration strategy promotes the best balance about lowest levels of emissions, vibrations, and noise if considered the number of inputs to be explored, becoming the searching for the optimum calibration a huge challenge for the development engineering team. This work proposes a methodology development in which complex problems can be solved by model based solutions regarding the best balance finding of emissions reduction and noise attenuation. The methodology is based in machine learning approach which provides a virtual behavior of engine phenomena making possible a wider comprehension of the problem and hence the opportunity to explore enhanced solutions. The study case scenario used to apply the method was a 6.4 liters engine which
Ruiz, Rodrigo Peralta MoraesSantos, Lucas ResendeNascif, Gabriel Nobre AlvesOliveira Ribeiro, DouglasPereira, Willyan
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
In the automotive industry, the zonal architecture is a design approach that organizes a vehicle’s electronic and communication systems into specific zones. These zones group components based on their function and physical location, enabling more efficient integration and simplified communication between the vehicle’s various systems. An important aspect of this architecture is the implementation of the Controller Area Network (CAN) protocol. CAN is a serial communication protocol developed specifically for automotive applications, allowing various electronic devices within a vehicle, such as sensors, actuators, and Electronic Control Units (ECUs), to communicate with each other quickly and reliably, sharing information essential for the vehicle’s operation. However, due to its limitations, there is a need for more efficient protocols like Automotive Ethernet and Controller Area Network Flexible (CAN FD), which allow for higher transmission rates and larger data packets. To centralize
Santos, Felipe CarvalhoSilva, Antônio LucasPaterlini, BrunoPedroso, Henrique GomesAlves, Joyce MartinsMilani, Pedro Henrique PiresKlepa, Rogério Bonette
Purified nickel and a large number of MgTi2 / NiO2 catalysts with various MgTi2 loadings were produced using the traditional incipient wetness method. X-ray crystallography and Fourier-transform infrared spectroscopy were used to examine the catalysts. To understand the material's microstructure better, the researchers investigated oxygen adsorption at 90K. The amine titration method was used to investigate the acidic characteristics of these catalysts. In a study on cumene cracking, these catalysts were employed. The catalyst was found to be amorphous up to a loading of 12 weight percent MgTi2, but at higher loadings, crystalline MgTi2 phase formed on an amorphous silica substrate. When NiO2 is doped with more MgTi2, there are significant differences in the structure, surface acidity, and catalytic activity of the catalysts. Catalysts with a higher MgTi2 loading are noticeably more acidic than those with a lower MgTi2 loading. A correlation between the amount of cracking activity and
Ashok Kumar, B.Dhiyaneswaran, J.Selvaraj, MalathiPradeepkumar, M.Shajeeth, S.
This study examines performance metrics and emission profiles of Kirloskar TV1 CI engine fuelled with blend containing waste transformer oil (WTO) biodiesel (40%), n-Heptane (10%), and diesel (50%) by volume (referred to as WTO40H10D50), with additional 10 lpm of hydrogen induction in the intake manifold. Effects of varied injection of fuel timing (19°, 21°, and 23°bTDC) and injection pressure (170, 210, and 240 bar) of WTO40H10D50 on diesel engine were analyzed at 100% engine loading condition. The findings indicate that an injection timing of 23°bTDC and an IP of 240 bar yield the highest BTE and lowest BSEC, suggesting optimal energy conversion efficiency. The influence of inducted H2 resulted in the lowest smoke opacity and HC emissions, demonstrating more complete and cleaner combustion. The results indicate at 23° bTDC of injection timing and 240 bar injection pressure produced best overall performance, with highest brake thermal efficiency and the lowest brake specific energy
Veeraraghavan, SakthimuruganPalani, KumaranDe Poures, Melvin VictorMadhu, S.
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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