Browse Topic: Catalysts

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Active site characterization of CuSCR catalysts under H2-ICE exhaust gas conditions2026-01-0361To be published on 04/07/2026
Hydrogen engines (H2-ICEs) can be a bridge technology for reducing carbon emissions until fuel cells and battery systems reach full commercial readiness. Because they share similar components to diesel, allowing the use of existing components and infrastructure, making them easier to scale. At the same time, H2-ICEs can deliver diesel-like performance, durability, and reliability while maintaining the advantage of fast refueling. Lean-burn H2-ICE offers enhanced thermal efficiency while minimizing engine-out NOx emissions. One of the main challenges under lean-burn H2-ICE operation is the significant drop in turbo-out temperatures combined with higher water content and the possible presence of unburned hydrogen in the exhaust. This study examines the impact of excess water and residual hydrogen on Cu-SCR durability, active site chemistry, and stability for the case with and without an upstream oxidation catalyst, through aging tests at 450 °C and 550 °C. Changes in Cu redox cycles were
Kim, Mi-Young, Daya, Rohil, Kamasamudram, krishna
Comparison of Ammonia Emission Characteristics Between Different Gasoline Vehicles Equipped with Three-Way Catalysts2026-01-0374To be published on 04/07/2026
In recent years, the tightening of vehicle emission regulations has led to a decreasing trend in regulated pollutants such as NOₓ and CO. However, the emission of ammonia (NH₃), which is unintentionally generated during the purification process in three-way catalyst of gasoline vehicles, has become a growing concern. NH₃ emissions from vehicles can serve as a precursor to PM2.5 and have been reported to cause local roadside pollution. Therefore, there is a growing need for on-road testing to identify conditions under which NH₃ is likely to be emitted. Furthermore, since engine control strategies vary among vehicle types, it is desirable to consider differences in emission behavior across different models. In this study, on-road NH₃ emissions were measured for multiple vehicle models with different powertrains, and the effects of engine behaviors and engine operating duration across vehicles on NH₃ emissions were investigated. To analyze differences in NH₃ emission behavior among
Ashizawa, Keigo, Fukunaga, Chisato, Gao, Tianyi, Sato, Susumu
Study on the Regulation of the Three-Phase Microenvironment in Low-Platinum MEA2026-01-0443To be published on 04/07/2026
With the growth of energy demand, fuel cells as efficient and clean energy devices, have attracted increasing attention. However, the high cost of membrane electrode assembly (MEA) restricts their large-scale application. Therefore, reducing the platinum usage and improving performance have become key research point. In this work, MEA was prepared and excellent performance of 1.52 W·cm-2 was achieved at a low platinum loading. The influence of different ionomer/carbon (I/C) ratio on the performance of fuel cells was systematically investigated. It was found that the performance of the MEA was the highest when the I/C ratio is 0.6. Quantifying hydrophilic and hydrophobic characteristics of catalyst layers with varying ionomer contents revealed that the proton conduction efficiency is optimal when the I/C ratio is 0.6. This balance established efficient proton conduction pathways, from the results of proton conduction impedance testing. SEM analysis demonstrated that pore structure
Li, Xin, Cai, Xin, Lin, Rui
Enhanced Catalyst Heating Control Strategy within Hybrid Electric Powertrain Architectures2026-01-0414To be published on 04/07/2026
Kudupley, Harshal, Pooyafar, Payam, Karogal, Indrasen, Patel, Nadirsh
Experimental Evaluation of After-treatment Solutions for Heavy-Duty Natural Gas Vehicles to meet future CNVII Regulations2026-01-0376To be published on 04/07/2026
The heavy-duty truck market in China has seen a significant increase in the adoption of natural gas-powered engines over the past two years. Simultaneously, the anticipated release of the China VII emissions regulation proposal by the end of 2025 is expected to impose stricter emissions limits on all heavy-duty engines, including new particulate number (PN10) thresholds analogous to those in the Euro 7 regulation. While tailpipe NOx and methane (CH4) emissions from natural gas engines can be mitigated through tighter lambda control and adjustments to catalyst volume and precious metal (PGM) loading, addressing particulate number (PN) emissions necessitate more advanced after-treatment solutions. Although natural gas combustion is virtually soot-free, the entrainment of lubricating oil into the combustion chamber, especially during cold-start conditions, poses a challenge, leading to potential exceedance of the proposed future China VII limits. Additionally, PN emissions from natural
Jiahui, Gao, Marc C, Besch, Ding, Ning, He, Suhao, zhao, Yuxin, Yixiao, Li, Shen, Ye
Study on the Effects of Different Catalyst Loadings on Diesel Engine Emission Characteristics with DOC Coupled SCR2026-01-0368To be published on 04/07/2026
DOC coupled with SCR is an important technical route for reducing gaseous pollutant emissions from diesel agricultural engines. Based on engine bench tests, this paper uses a diesel engine as a prototype to experimentally study the impact of different catalyst loadings on the emission characteristics of diesel engines when coupled with DOC and SCR. The results show that the higher the loading of the DOC catalyst, the greater the exhaust back pressure loss, with the maximum pressure difference reaching 4.9 kPa. The temperature difference before and after the DOC has a smaller impact with varying catalyst loadings. The higher the loading of the DOC catalyst, the stronger the catalytic activity for CO and THC. At medium and low loads, the impact of catalyst loading is more significant, while at high loads, it has a smaller impact. The higher the loading of the DOC catalyst, the stronger the oxidation ability for NO. Under external characteristic conditions, due to the higher engine
zhang, Yunhua, Junzhe, Li, Lou, Diming, Fang, Liang
Experimental and kinetic Modeling Study of Aged Three-way Catalyst Performance2026-01-0373To be published on 04/07/2026
A comprehensive global kinetic model has been developed for an aged commercial Three-Way Catalyst (TWC), incorporating key reaction pathways including oxidation of CO, CH₄, C₂H₆, and H₂; reforming of CH₄ and C₂H₆; the water-gas shift reaction; and NO reduction via CO and H₂. The model also accounts for oxygen storage capacity (OSC) and its dynamic interaction with CO and H₂. To calibrate kinetic parameters, systematic bench-scale flow reactor experiments were conducted under lean, stoichiometric, and rich conditions. Performance metrics focused on CH₄ and C₂H₆ oxidation and reforming across varying O₂ and CO concentrations, and NO reduction with CO and H₂ under different oxygen levels. Experimental results revealed CO inhibition effects on CH₄ and C₂H₆ reforming. NO conversion was observed between 150°C and 600°C, with H₂-driven reduction producing NH₃, N₂, and N₂O depending on lambda (λ). Under rich conditions, complete NO conversion occurred from 150°C, while lean conditions showed
Raj, Richa, Kim, Mi-Young, AIGBIREMOLEN, Grace, Srinivasan, Anand
Optimization of Transesterification Parameters for Sustainable Biodiesel Production from Pongamia pinnata Oil2026-01-0470To be published on 04/07/2026
The rapid depletion of fossil fuel resources, rising fuel costs, and growing environmental concerns have highlighted the urgent need for sustainable and eco-friendly alternative energy sources . Among these, biodiesel derived from renewable resources has gained significant global attention. Vegetable oils, particularly non-edible varieties, present a viable alternative fuel for compression ignition (CI) engines when converted into biodiesel. Pongamia Pinnata (Ponamia Pinnata) oil, a non-edible vegetable oil, is abundantly available in Ponamia Pinnata-producing countries such as India (. However, limited research has been conducted on its utilization and the optimization of its transesterification process. Due to the high free fatty acid (FFA) content (3.3%), direct base-catalyzed transesterification of Pongamia Pinnata oil was ineffective in producing biodiesel. Consequently, an acid pretreatment step was employed to reduce the FFA level to 0.9%, enabling successful base-catalyzed
Nigade, Shubhangi Sambhaji, Jadhav, Sangram
Impact of Hydrogen on Methane and Pollutant Emissions over Three-Way Catalysts with Natural Gas–Hydrogen Blends2026-01-0357To be published on 04/07/2026
Natural gas (NG) is a domestically abundant, low-cost fuel with the potential to displace gasoline and diesel fuel in commercial and off-road vehicles. NG engines typically produce lower engine-out pollutant emissions, such as NOx, CO and particulate matter, which could simplify emission control systems. Blending NG with hydrogen (H₂) can improve engine performance and increase combustion efficiency to further reduce engine-out emissions. Additionally, the presence of H2 in the exhaust stream may also facilitate the catalytic conversion of methane and other pollutants, resulting in cleaner tailpipe emissions. This study evaluates the impact of H2 on the conversion of methane, CO, and NOx emissions on a commercial three-way catalyst (TWC) in a flow reactor using synthetic gas mixtures that simulate stoichiometric engine exhausts with NG or NG+H₂ combustion. The work examines whether, and how, the additional amount of H₂ in the exhaust stream affects the conversion efficiency of methane
Prikhodko, Vitaly, Wang, Min, Park, Yeonshil, Chen, Hai-Ying, Pihl, Josh
Simultaneously NOx and Fuel Reduction for Off-Road2026-01-0296To be published on 04/07/2026
Simultaneously reducing criteria pollutants and fuel consumption is important for clean air and improving vehicle total cost of ownership. The goal of this effort was focused on a 90% NOx reduction and 10% fuel savings for an off-road 407 kW diesel engine. The baseline was a current production Fiat Powertrain 13L engine and aftertreatment system meeting 0.4 g/kW-hr NOx. The baseline system was quantified over the NRTC, RMC, new low load cycle and five field cycles. A next generation engine was built incorporating many fuel-efficient approaches such as higher compression and reduced parasitic loads. Cylinder deactivation and EGR pump technologies were added to this engine as well. The combination was optimized prior to adding advanced aftertreatment systems, showing the trade-off of engine out NOx and exhaust temperature. Two next-generation catalyst technologies were employed into a LO-SCR plus main SCR system, both with and without an electric heater upstream of the LO-SCR. These
McCarthy, James, Wine, Jonathan, Bradley, Ryan, Hasseman, Andy, Prikhodko, Vitaly, Howell, Thomas
Effect of Exhaust Gas Components on Oxygen Storage Capacity Measurements of Automotive Catalysts2026-01-0360To be published on 04/07/2026
Three-way catalytic converters (TWC) are one of the most popular methods to help reduce harmful tailpipe emissions emitted from internal combustion (IC) vehicles. To help improve conversion efficiency, TWCs can store and release oxygen via an oxygen storage capacity (OSC) mechanism. During engine control unit (ECU) calibration, on board OSC measurements are correlated to TWC and vehicle emissions to monitor emissions performance throughout the full useful life (FUL) of the vehicle. It is known that different test conditions, including temperature, space velocity and background gases in the exhaust stream affect OSC measurement, potentially altering the calculated OSC values and thus the perceived level of OSC and emissions preformance during operation. This study utilises an OMEGA test bench to complete OSC measurements on the full-scale automotive catalyst samples to quantify the effects of different background gases including carbon monoxide, hydrocarbons and nitric oxide on OSC
Mc Grane, Liam, Douglas, Roy, Irwin, Kurtis, Woods, Andrew, Elliott, Matthew, Istrate PhD, Oana, Nockemann, Peter
Alternate Catalyst for DOC in a Catalytic Converter2026-28-0016To be published on 02/12/2026
Emission norms have become much more stringent to reduce emissions from vehicles. Diesel engines in particular are the predominant contributors to higher emissions. Diesel Oxidation Catalyst (DOC) in diesel engine catalytic converter systems is the crucial component in reducing harmful emissions such as Carbon Monoxide (CO) and unburnt Hydrocarbons (HC). DOCs often rely on expensive noble metals like platinum, palladium, and rhodium as catalyst materials. This significantly raises the cost of emission control units. The proposed idea is to explore MnO2-CeO₂ (Manganese Oxide, Cerium Oxide) as an alternative catalyst to traditional DOC materials. The goal is to deliver effective oxidation performance while reducing overall system cost. MnO2-CeO₂ catalysts are promising because of their good low-temperature activity, oxygen storage capacity, and redox behavior. These features are helpful for diesel engines that operate under various conditions. They improve the oxidation of CO and HC
C, Jegadheesan, T, Karthi, Rajendran, Pawan, Muruganantham, Kowshiik, S, Vaitheeshwaran
Introducing a New Catalyst Family in Gasoline Aftertreatment2026-26-02311/16/2026
This paper is to introduce a new catalyst family in gasoline aftertreatment. The very well-known three-way catalysts effectively reduce the main emission components resulting from the combustion process in the engine, namely THC, CO, and NOx. The reduction of these harmful emissions is the main goal of emission legislation such as Bharat VI to increase air quality significantly, especially in urban areas. Indeed, it has been shown that under certain operating conditions, three-way catalysts may produce toxic NH3 and the greenhouse gas N2O, which are both very unwanted emissions. In a self-committed approach, OEMs could want to minimize these noxious pollutants, especially if this can be done with no architecture change, namely without additional underfloor catalyst. In most Bharat VI gasoline aftertreatment system architectures, significant amounts of NH3 occur in two phases of vehicle driving: situations with the catalyst temperature below light-off, which appear after cold start or
Kuhn, Sebastian, Magar, Avinash, Kogel, Julius, Lahousse, Christophe
Optimizing Catalyst Substrate Technology for Gasoline Vehicles in Indian Market2026-26-02121/16/2026
Emission norms are getting stringent day by day, posing new challenges such as stricter emission limits and compliance to Real Driving Emissions (RDE). Consequently, there is a pressing need to minimize emissions during cold start, transient phases, and high exhaust flow regions. Achieving this objective requires enhancing the efficiency of after-treatment system and optimization of engine calibration. This paper discusses the approach to improve the efficiency of after-treatment system by enhancing the substrate design features such as cell density, wall thickness, and cell shape etc. The assessment was conducted to determine the emission performance advantages of substrates with higher cell densities of up to 900 cells per square inch (cpsi) and thinner web thicknesses down to 2.5 mil. This evaluation included both square and hexagonal cell shapes, comparing them to traditional substrates featuring 600 cpsi and 4.3 mil thickness. The evaluation has also included an assessment of
Singh, Harmeet, Kumar, Amit, Mahra, Deepti, Khanna, Vikram
CS Structure: New Metallic Catalyst Substrate Generation for 2- and 3-Wheeler Applications2026-26-02201/16/2026
Affordable, efficient and durable catalytic converters for the two and three-wheeler industry in developing countries are required to reduce vehicle emissions and to maintain them at a low level; and therefore, to participate in a cleaner and healthier environment. Especially, metallic catalyst substrates developed by Emitec Technologies GmbH with structured foils like the Longitudinal Structure (LS), or LS-Design® are fully compatible to this effort with more than 70% share of produced 2/3 Wheelers metallic catalyst substrates for the Indian market in 2024. One decade after the market introduction of this LS structure, Emitec Technologies GmbH will introduce now a new generation of foil structure: the Crossversal Structure (CS) or CS-Design®, that improves further the affordability, the efficiency of metallic catalytic converters, keeping the durability at same level as previous substrate generation. The paper will briefly review the development of metallic substrates for 2/3 wheelers
Jayat, Francois, Seifert, Sven, Bhalla, Ashish, Ganapathy, Narayana Prakash
A Case Study of Emission Optimization using Machine Learning2026-26-02291/16/2026
The Exhaust Emission Control is a vital part of automotive development aimed at ensuring effective control of pollutants such as NOx, CO, and HC. The traditional method of calibrating emission control strategies is a highly time-consuming process, which requires extensive vehicle testing under a variety of operating conditions. The frequent updates in emission legislation requires a high-efficiency process to achieve a faster time-to-market. The use of Machine Learning (ML) in the domain of emission calibration is the need of the hour to proactively improve the process efficiency and achieve a faster time-to-market. This paper attempts to explores emerging trend of Machine Learning (ML) based data analysis that have improved the overall process efficiency of emission control calibration. The data generated by automated programs could be used directly in data analysis with minimal or no need for data cleaning. The Machine Learning (ML) models could be trained by historical data from
Dhayanidhi, Hukumdeen, Balasubramanian, Karthick, A, Akash
All New 1.2L Turbocharged Gasoline Direct Injection Engine from Tata Motors2026-26-00711/16/2026
There is continuous push from the legislation for stringent fuel economy and emission regulations while the modern customers are demanding more engaging driving experience in terms of performance and refinement. To meet this Tata Motors has developed an advanced 1.2L 3-cylinder turbocharged gasoline direct injection engine. This next-generation powertrain delivers optimum efficiency, reduced emissions, superior performance with refined NVH characteristics. The key features used to enable these demanding requirements includes a 35 MPa fuel injection system, Miller Cycle operation and electrically actuated variable nozzel turbocharger (VNT). A uniquely designed BSVI complaint (WLTP ready) exhaust after-treatment system with Four-Way Conversion Catalyst (FWC+TM) ensures optimum emission control. A centrally mounted variable cam phaser minimizes pumping losses. The lightweight yet rigid all-aluminum engine structure, featuring an integrated structural oil sump, enhances durability and
Hosur, Viswanatha, Ghadge, Ganesh Narayan, Joshi, Manoj, Jadhav, Aashish, Panwar, Anupam
Accelerated Aging Methodology for Catalyst on Engine Test Benches: Practical Considerations for a Successful Implementation of the Methodology2025-36-008712/18/2025
The durability of automotive catalysts is a critical factor in ensuring compliance with strict environmental regulations throughout the vehicle’s lifespan. Accelerated aging methods are widely used in the industry to predict catalyst degradation over a reduced period, allowing for performance optimization and ensuring their effectiveness in emission reduction. The ABNT NBR 16897:2021 standard establishes general guidelines for these tests but does not define in detail all the experimental conditions necessary for practical implementation. Addressing this gap, this study proposes the application and development of a standardized experimental procedure for accelerated catalyst aging, aligned with current regulations and adapted to test conditions in an engine dynamometer test bench. The objective is to provide a solid technical foundation, filling gaps for future implementations of this methodology, allowing investigations into the durability of aftertreatment systems and assisting both
Yana, Diego Andree Reynoso, Pradelle, Florian, Braga, Sergio Leal, Sánchez, Fernando Zegarra, Machado, Guilherme Bastos, Carvalho, Rogério Nascimento de, Silva, Katia Moniz da
Biodiesel Production via Homogeneous Route (KOH) and Heterogeneous Route (K 2 O/Nb 2 O 5 )2025-36-011612/18/2025
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Coelho, Gabriella Vilela, Alvarez, Carlos Eduardo Castilla, Ribeiro, Jessica Oliveira Notório
Performance Analysis of a Hydrogen-blended Naturally Aspirated Gas Engine with a Dedicated Exhaust Gas Recirculation System2025-32-004611/3/2025
With the publication of the Renewable Energy Directive (RED) III in 2022, the European Union increased its renewable energy consumption target to 42.5% by 2030. Consequently, gaseous fuels derived from renewable electricity, particularly green hydrogen, are expected to play a pivotal role in the decarbonization of the energy sector. One promising application of green hydrogen is its integration into combined heat and power (CHP) plants, where it can replace natural gas to reduce CO2 emissions. Pure hydrogen as fuel or blended with natural gas has demonstrated potential for lowering both pollutant emissions and fuel consumption while maintaining or even enhancing engine performance. But it is expected, that the amount of available green hydrogen will be limited in the beginning. So new engine systems with hydrogen and natural gas for CHP plants are required, that offer more CO2-benefit and NOx reductioon than from fuel substitution only. In the LeanStoicH2 project, a novel approach was
Salim, Naqib, Beltaifa, Youssef, Kettner, Maurice
Investigation of Degradation of Catalyst Performance due to Phosphorus Poisoning in Practical Catalysts2025-32-007311/3/2025
Although exhaust gas regulations for internal combustion engines have been in place for quite some time, they are still getting stricter every year. Motorcycles are no exception. Exhaust gas regulations for after-degradation durability have already been applied, and the next regulation is expected to require vehicles in use in the market to meet the exhaust gas regulation values. Technology to comply with exhaust gas regulations mainly deals with catalyst performance degradation. The main issues are metal sintering and poisoning. In particular, it is difficult to explain clearly the change in catalyst performance due to poisoning alone, as it is necessary to distinguish it from sintering and to determine the distribution of deterioration. However, phosphorus poisoning from oil cannot be ignored unless oil consumption is reduced to zero. In order to understand the change in practical catalyst performance due to poisoning with a distribution of degradation, it is necessary to explain the
Ibara, Takeru, Itou, Shiori, Yusa, Kazuma, Kinoshita, Hisatoshi, Motegi, Takuya
Reactivity Retention of Modern Converters for Stringent Emission Control2025-01-040110/7/2025
The growing emphasis on environmental protection and sustainability has resulted in increasingly stringent emission regulations for automotive manufacturers, as demonstrated by the upcoming EURO 7 and 2027 EPA standards. Significant advancements in cleaner combustion and effective aftertreatment strategies have been made in recent decades to increase the engine efficiency while abiding by the emission limits. Among the exhaust aftertreatment strategies, three-way catalyst has remained the primary solution for stoichiometric burn engines due to its high conversion efficiency and ability to simultaneously allow both oxidative and reductive reactions in a single stage with spatial separation due to the oxygen storage capabilities of ceria. However, fuel and lubricant-borne sulfur and phosphorus compounds have been shown to have a significant long-term effect on the activity of three-way catalysts, particularly during the lean-rich transitions and oxygen storage processes. In the present
Sandhu, Navjot Singh, Yu, Xiao, Jiang, Chuankai, Ting, David, Zheng, Ming
Water Injection as an Enabling Technology for Stoichiometric High Performance Normally Aspirated Engines2025-24-00279/7/2025
The mainstream automotive market is rapidly transitioning to electrified and fully electric powertrains. Where gasoline engines are still employed, they are frequently turbocharged units with relatively low maximum engine speed and modest power density. The hypercar class, in contrast, has recently seen somewhat of a renaissance in high performance, high speed, naturally aspirated gasoline engines, which are prized for their emotional contribution to the vehicle. In order to guarantee high conversion efficiency of a Three Way Catalyst in the exhaust system, an engine must be operated at stoichiometric air-fuel ratio. At high power density, this may result in very high exhaust gas temperature, which poses a risk to engine and vehicle hardware. A number of technological interventions to extend the maximum stoichiometric performance whilst respecting component limitations have already been described in the literature, but many of these are not applicable to specific engine architectures
Corrigan, Dáire James, Villa, Davide, Penazzi, Eugenio, Meghani, Amit, Knop, Vincent, Caroli, Giacomo, Frigeri, Davide, Ruggiero, Federico, Malaguti, Simone, Postrioti, Lucio, Maka, Cristian
Combined Virtual and Experimental Approach to Develop Highly Efficient Metallic Catalyst for New World Wide Emission Legislation2025-24-00809/7/2025
The market penetration of Battery Electric Vehicles (BEV) in Europe is not following the foreseen scenario. This is related to several factors, such as uncertainty of the second-hand value of BEV, real driving range under cold conditions and availability of charging stations. Even if the European Community is still planning a full ban of Internal Combustion Engines (ICE) by 2035, in the rest of the world a more technology neutral approach is being pursued. Car manufacturers are developing different powertrain architectures, from mild- to full-hybrid and Range Extenders (REEX). In this context of different emission regulations, and wide range of powertrain architectures, the focus of the development will be the increase of catalyst efficiency without any big impact on exhaust aftertreatment cost. In previous work [1] the authors have used a 1D simulation approach to support the optimization of metallic TWC substrate for the High Power Cold Start use case. Additionally, a 3D CFD was used
Montenegro, Gianluca, Della Torre, Augusto, Marinoni, Andrea, Onorati, Angelo, Klövmark, Henrik, Laurell, Mats, Pace, Lorenzo, Konieczny, Katrin
Investigation of a Lambda Leap Strategy for Hydrogen Internal Combustion Engines to Balance Efficiency with Performance and Vehicle Packaging2025-24-00709/7/2025
The paper reports an investigation into employing a “lambda leap” (λ leap) strategy for hydrogen internal combustion engines (H₂ICEs), wherein inherently low emissions of oxides of nitrogen (NOx) are afforded at light load via operation at lambda 2.5, and at higher load by operation at stoichiometry utilizing a three-way catalyst (TWC) for NOx control. This approach means it is necessary under transient operation to “leap” between high values of lambda and stoichiometry from one cycle to the next, in order to avoid completely the λ ≈ 1.3 area where high combustion NOx is generated away from lambda equal to 1; this is because lean catalysis of NOx will be extremely challenging at the rate that it is generated there. To achieve this, a short cam profile was introduced to reduce air mass flow by 57.5%, enabling this leap without changing the fuel injection amount, while preserving favorable combustion characteristics via an early Miller cycle. The study models a 2.0 L inline four-cylinder
Fong Cisneros, Eric J., Kodaboina, Raghu Vamsi, Vorraro, Giovanni, Turner, James W. G.
Effect of Ignition Condition and Fuel Octane Number on Knock Intensity in a Small 2-Stroke Engine2025-01-02116/16/2025
Internal combustion engines (ICEs) remain widely used in automotive transportation for their high energy storage system efficiency and economic benefits. The 4-stroke engine has dominated all other forms to date, because the Otto cycle is relatively simple to understand. However, the significant benefits such as less pumping work and friction, lighter construction of 2-stroke engine, are attractive for applications that prioritize the simplicity and power density as well as meet the emission regulations. The disadvantages of the 2-stroke engine are mainly caused by the lack of sufficient scavenging process. Also, the overlap of the intake and exhaust phases results in charge short-circuiting, more fuel consumption and high unburned hydrocarbon emissions. For these reasons, it is difficult for 2-stroke engines to achieve stoichiometric combustion, making them incompatible with three-way catalyst to control emissions. The residual exhaust gas in the cylinder makes the spark ignition
Liu, Jinru, Yamazaki, Yoshiaki, Otaki, Yusuke, Kato, Hayato, Yokota, Takumi, Iijima, Akira
Development of After-Treatment Systems and Control Strategy for a Hybrid-Dedicated Homogeneous Lean Burn Engine2025-01-02176/16/2025
The development of lean-burn gasoline engines has continued due to their significant improvements in thermal efficiency. However, challenges associated with NOx emissions have hindered their mainstream adoption. As a result, the development of an effective NOx after-treatment system has become a key focus in lean-burn engine research. Additionally, HC emissions pose another challenge, as they tend to increase under lean combustion conditions while their conversion efficiency simultaneously declines. This study presents a novel after-treatment system incorporating a lean NOx trap(LNT) and a passive SCR(pSCR) system. This configuration enables efficient NOx reduction at a competitive cost while maintaining operational simplicity. Moreover, conventional catalyst technologies, including three-way catalysts (TWCs) and fuel-cut NOx traps (FCNTs), were optimized to maximize conversion performance under lean operating conditions. To further enhance system performance, various control
Oh, Heechang, Lee, Jonghyeok, Sim, Kiseon, Lim, SeungSoo, Park, Jongil, Park, Minkyu, Kang, Hyunjin, Han, Donghee, Lee, Kwiyeon, Song, Jinwoo
Impact of Reduced Catalytic Activity on Passive Regeneration of Catalyzed Diesel Particulate Filters2025-01-01856/16/2025
Oxidation catalysts can greatly improve the regeneration efficiency of diesel particulate filters (DPF) by providing sufficient levels of NO2 for low-temperature soot oxidation. As for other automotive catalysts, catalyzed DPFs are subject to aging effects, resulting in decreased performance of the NO oxidation reaction. The life span of DPFs generally only considers the elevated back pressure as a consequence of the accumulation of ash. However, with reduced catalytic activity and impaired functionality of the regeneration process there is a risk of premature replacement of the catalyzed DPF or accumulation of soot above critical levels. In this study, a new exhaust aftertreatment system has been developed to accommodate laboratory-scale catalysts and DPFs for testing with full-size heavy-duty engines. The modified exhaust aftertreatment set-up was used together with a rig for accelerated soot and ash loading to assess the impact of catalyst aging on regeneration performance under
af Ugglas, Samuel, Finker, Pascal, Ersson, Anders, Yao, Dawei, Pettersson, Lars J., Kusar, Henrik
A Successful Catalyst Design for Advanced Zinc-Iodine BatteriesTBMG-532066/1/2025
Aqueous zinc-ion batteries (ZIBs) have attracted extensive attention due to their high safety, abundant reserves, and environmental friendliness. Iodine with high abundance in seawater (55 μg L-1) is highly promising for fabricating zinc-iodine batteries due to its high theoretical capacity (211 mAh g-1) and appropriate redox potential (0.54V). However, the low electrical conductivity of iodine hinders the redox conversion for an efficient energy storage process with zinc. Additionally, the formed soluble polyiodides are prone to migrate to the Zn anode, leading to capacity degradation and Zn corrosion.
Influence of Exhaust Gas Recirculation on Knock in a Spark Ignition Engine Fueled with Ethanol–Gasoline Blends03-18-03-00194/28/2025
Exhaust gas recirculation (EGR) is widely used in spark ignition engines to reduce throttling losses, decrease exhaust gas temperatures, increase efficiency, and suppress knock. However, the effectiveness of EGR as a knock suppressor is dependent on the fuel type and operating condition. In this study, the effectiveness of EGR to suppress knock was tested with E10, E30, E50, E75, and E100 at a moderately boosted condition. It was found that EGR was effective at suppressing knock with E10, but high EGR rates were required to achieve a knock suppression effect with E30 and E50. No knock suppression effect was observed with E75 and E100 across all tested EGR rates. With E30 and E50, EGR that was passed through a three-way catalyst was more effective at suppressing knock at all EGR rates. Chemkin modeling with neat ethanol revealed that nitric oxide enhanced ignition by increasing the hydroxyl radical concentration in the end gas, resulting in earlier auto-ignition. Directly seeding nitric
Gandolfo, John, Gainey, Brian, Lawler, Benjamin
Investigation on Degradation Process of PdRuIr/CZ “Pseudo-Rh” Catalysts Used for Motorcycles2024-32-00164/18/2025
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, Takuya, Tatara, Shunya, Takamoto, Shunpei, Doi, Kosuke
Coupled Analysis of First Principle Calculation and Chemical-Kinetics Simulation to Predict the Activity of Three Way Catalyst2024-32-00044/18/2025
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, Kazuya, Kusaba, Hiroki, Miyoshi, Tomoya, Yoshida, Hiroshi, Tsuchizaki, Hiroyuki, Machida, Masato
Experimental Study on Thermo-Catalytic Ammonia Decomposition into Hydrogen2024-32-01184/18/2025
In order to rapidly achieve the goal of global net-zero carbon emissions, ammonia (NH3) has been deemed as a potential alternative fuel, and reforming partial ammonia to hydrogen using engine exhaust waste heat is a promising technology which can improve the combustion performance and reduce the emission of ammonia-fueled engines. However, so far, comprehensive research on the correlation between the reforming characteristic for accessible engineering applications of ammonia catalytic decomposition is not abundant. Moreover, relevant experimental studies are far from sufficient. In this paper, we conducted the experiments of catalytic decomposition of ammonia into hydrogen based on a fixed-bed reactor with Ru-Al2O3 catalysts to study the effects of reaction temperature, gas hour space velocity (GHSV) and reaction pressure on the decomposition characteristics. At the same time, energy flow analysis was carried out to explore the effects of various reaction conditions on system
Li, Ze, Li, Tie, Chen, Run, Li, Shiyan, Zhou, Xinyi, Wang, Ning
Development of NOx Storage Catalyst and Investigation of Deterioration Mechanism for Small Powertrains2024-32-00974/18/2025
In response to the evolving landscape of exhaust gas regulations for small powertrains, reducing NOx emission is increasingly important. This study deeply investigated the feasibility of a NOx storage catalyst (NSC) containing cerium oxide (CeO2) and barium oxide (BaO) for reducing NOx emission. The key functions, NOx storage and reduction performances were evaluated, and deterioration mechanisms were explored through performance evaluations and physical property analyses. The findings revealed a strong correlation between the size of CeO2 crystals and NOx storage performance at low temperature, such as those encountered during city driving conditions. Conversely, at high temperature, such as those during highway driving conditions, NOx storage performance correlated well with sulfur deposition, suggesting that the formation of barium sulfate (BaSO4) contributes to the deactivation. This experiment also showed a strong correlation between NOx reduction performance and BaSO4 formation
Nakano, Fumiya, Koito, Yusuke
Advanced Aftertreatment System Meeting Future HD CNVII Legislation II2025-01-84784/1/2025
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, Yan, Fu, Guangxia, Chen, Shuyue, Aberg, Andreas, Jiang, Shuiyan, Zhang, Jun
Effect of Catalyst Coating Strategy on NOx Reduction and Passive Soot Oxidation for Selective Catalytic Oxidation-Selective Catalytic Reduction Catalyst on Diesel Particulate Filter2025-01-84904/1/2025
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-jie, Tan, Piqiang, Yao, Chaojie, Lou, Diming, Hu, Zhiyuan, Yang, Wenming
Improved Three-Way Catalyst with Ignition Layer for Reducing Cold Emissions2025-01-84824/1/2025
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, Takahiro, Takagi, Nobuyuki, Tojo, Takumi, Fujita, Naoto, Mori, Mizuho, Toda, Yosuke
Gasoline Particulate Filter Modeling with Catalytic Washcoat and Ash Accumulation and Transient Soot Distribution Prediction2025-01-84834/1/2025
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, Pengze, Cheng, Zhen
Fundamental Science on Oxygen Storage Capacity of Cerium Complex Oxides for Advanced On-Board Diagnostics (1) Kinetic Observation of Cerium Valence Change Using Synchrotron Radiation2025-01-84744/1/2025
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, Hirohisa, Matsumura, Daiju, Uegaki, Shinya, Hamada, Shota, Aotani, Takuro, Kamezawa, Saeka, Nakamoto, Masami, Asai, Shingo, Mizuno, Tomohisa, Takamura, Riku, Goto, Takashi
A Study on Cetane on Demand Technology Part 1 - Development of Fuel Reformer to Improve Fuel Ignitability2025-01-84474/1/2025
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, Kohtaro, Yamada, Yoshikazu, Matsuura, Katsuya, Kudo, Tomohide, Chishima, Hiroshi, Al-Taher, Maryam, Kalamaras, Christos, Albashrawi, Reem
High-Performance and Stable Three-Way Catalyst Achieved Via Ultrasonic Treatment for Gasoline Vehicle Emission Control2025-01-84804/1/2025
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, Shijie, Lv, Yanan, Wang, Weidong, Rao, Chao, Wei, Wei, Mao, Bingbin, Chen, Tao, Zhao, Huawang
Development of a Zeolite-Based (HC Trap Type) Cold-Start Catalyst (CSC) for the Future more Stringent Vehicle Tailpipe Emission Standards, Part III2025-01-84814/1/2025
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, Lifeng, Zhao, Fucheng, Wei, Hong, Zhao, Pengfei, Zhao, Jiajia, Ma, Ruibo, Newman, Philip, Wang, Lin, Qian, Wangmu, Qian, Menghan
Biodiesel and Renewable Diesel Blends Oxidation by Diesel Oxidation Catalyst2025-01-85004/1/2025
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, Venkata, Weber, Phillip, McCormick, Robert, Howell, Steve
Effects of Post-Injection Strategy on the Performance of Diesel Catalyst-Heating Operation2025-01-84144/1/2025
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, Dario, Lee, Sanguk, Cho, Seokwon, Busch, Stephen, Wu, Angela, Narayanan, Abhinandhan, Abboud, Rami
Fundamental Science on Oxygen Storage Capacity of Cerium Complex Oxides for Advanced On-Board Diagnostics (2) Quantitative Observation of Oxygen Released from Cerium Complex Oxides2025-01-84764/1/2025
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, Shota, Uegaki, Shinya, Tanabe, Hidetaka, Nakayama, Tomohito, Jinjo, Itsuki, Kurono, Seita, Oishi, Shunsuke, Narita, Keiichi, Onishi, Tetsuro, Yasuda, Kazuya, Matsumura, Daiju, Tanaka, Hirohisa
High-Efficient and Cost-Effective Three-Way Catalyst Substrate Design for Plug-in Hybrid Electric Vehicle2025-01-85284/1/2025
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, Jiming, Li, Chunbo, Feng, Xiangyu, Chen, Xiaolang, Boger, Thorsten, Tian, Lichen, Hu, Xianli, Zeng, Jun, Tian, Tian, Gao, Bojun, Li, Dacheng, Liu, Shicheng, Jiang, Fajun
Analysis of Trapped Gases within an Aftertreatment System Reacting over a TWC after Engine Is Stopped2025-01-84994/1/2025
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 Eduardo, Lacdan, Ma Camille, Hara, Kenji, Otsuki, Yoshinori
Impact of Oxidation Catalyst Formulation and Space Velocity on Performance with Conventional and Renewable Fuels2025-01-84954/1/2025
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, Venkata, Weber, Phillip, McCormick, Robert, Howell, Steve
First Principle Study of Catalyst’s Influence on Self-Inhibition Effect and By-Products Formation of Lean NOx Trap2025-01-70421/31/2025
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, Mingli, Liu, Yaodong, Qu, Hanshi, Duan, Jiaquan, Zhang, Qiqi, Qian, Dingchao, Wang, Zhenxi, He, Zhentao
Degradation Analysis of Aged Fuel Cell Stack via Polarization Change Curve2025-01-70901/31/2025
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, Chenbing, Wu, Hailong, Ruyi, Wang
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