Browse Topic: Three-way catalysts

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All New 1.2L Turbocharged Gasoline Direct Injection Engine from Tata Motors2026-26-0071To be published on 01/16/2026
A continuous stress on meeting stringent emissions regulations alongside rising consumer expectations for enhanced driving performance and refinement on powertrain applications on passenger cars. To address this customer aspirations Tata Motors has engineered the advanced 1.2L 3-cylinder turbocharged gasoline direct injection engine HYPERION. This next-generation powertrain is designed to maximize efficiency, lower emissions and deliver superior performance with improved noise, vibration, and harshness (NVH) characteristics. Key innovations includes highly optimized fuel injectors injector operating at 35 MPa, CVO-3 (3rd Gen Controlled Valve Operation), Miller Cycle with Electrically actuated VGT turbocharger and an AI-enabled engine management system, which collectively enhances efficiency and performance. The exhaust after-treatment system incorporates a Three-Way Catalyst (TWC) and an integrated Four-Way Conversion Catalyst (FWC+TM) for efficient emission control. The BS6 phase 2
Hosur, Viswanatha, Ghadge, Ganesh Narayan, Joshi, Manoj, Jadhav, Aashish, Panwar, Anupam
Introducing a new catalyst family in gasoline aftertreatment2026-26-0231To be published on 01/16/2026
This paper is to introduce a new catalyst family in gasoline aftertreatment. Indeed, it has been shown that under certain driving conditions, three-way catalysts produce significant amounts of toxic NH3 and the strong 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 this paper we will compare different approaches: regular underfloor TWC, SCR derived from diesel aftertreatment, gasoline dedicated Ammonia Slip Catalyst (ASC) and especially developed novel gasoline Secondary Emission Treatment (SET) catalyst, providing both ammonia abatement and underfloor three-way functionality. The data will show that SCR only reduces NH3 from a passive SCR reaction in a limited amount in the cold start including the need of oxygen presence, namely secondary air introduction. ASC is efficient in cold
Kuhn, Sebastian, Magar, Avinash, Kogel, Julius, Lahousse, Christophe
Performance Analysis of a Hydrogen-blended Naturally Aspirated Gas Engine with a Dedicated Exhaust Gas Recirculation System2025-32-004611/03/2025
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
Reactivity Retention of Modern Converters for Stringent Emission Control2025-01-040110/07/2025
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 Engines2025-24-002709/07/2025
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 Legislation2025-24-008009/07/2025
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 Packaging2025-24-007009/07/2025
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 Engine2025-01-021106/16/2025
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 Engine2025-01-021706/16/2025
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
Influence of Exhaust Gas Recirculation on Knock in a Spark Ignition Engine Fueled with Ethanol–Gasoline Blends03-18-03-001904/28/2025
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
Coupled Analysis of First Principle Calculation and Chemical-Kinetics Simulation to Predict the Activity of Three Way Catalyst2024-32-000404/18/2025
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
Improved Three-Way Catalyst with Ignition Layer for Reducing Cold Emissions2025-01-848204/01/2025
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 Prediction2025-01-848304/01/2025
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
High-Performance and Stable Three-Way Catalyst Achieved Via Ultrasonic Treatment for Gasoline Vehicle Emission Control2025-01-848004/01/2025
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
High-Efficient and Cost-Effective Three-Way Catalyst Substrate Design for Plug-in Hybrid Electric Vehicle2025-01-852804/01/2025
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 Stopped2025-01-849904/01/2025
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 Fuels2025-01-849504/01/2025
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
Catalyzed Gasoline Particulate Filter Performance from Fresh to Full Useful Life2024-01-431111/05/2024
The gasoline particulate filter (GPF) represents a durable solution for particulate emissions control in light-duty gasoline-fueled vehicles. It is also seen as a viable technology in North America to meet the upcoming US EPA tailpipe emission regulation, the proposed “Multipollutant Rule for Model Year 2027”. The goal of this study was to track the evolution of tailpipe particulate emissions of a modern GTDI light duty vehicle under typical North American mileage accumulation; from a fresh state to 4000-mile, and finally to its full useful life of 150,000-miles. For this purpose, a production TWC + GPF after-treatment system was installed in place of the T3B85 TWC-only system. Chassis dyno emissions testing was performed at the pre-determined mileage points with on-road driving conducted for the necessary mileage accumulation. This report will show the outstanding filtration durability and enhanced particulate control and of the current GPF technology all the way to 150,000 miles for
Craig, Angus, Warkins, Jason, Beattie, James, Nipunage, Sanket, Moser, David, Day, Ryan, Banker, Vonda
Emission Optimization of the Cold Start Behavior of a CNG Engine with Electrically Heated Catalyst and Secondary Air Injection2024-24-002809/18/2024
Decarbonization and a continuous reduction in exhaust emissions from combustion engines are key objectives in the further development of modern powertrains. In order to address both aspects, the DE4LoRa research project is developing an innovative hybrid powertrain that is characterized by the highly flexible combination of two electric motors with a monovalent compressed natural gas (CNG) engine. This approach enables highly efficient driving in purely electric, parallel and serial operating modes. The use of synthetic CNG alone leads to a significant reduction in CO2 emissions and thus in the climate impact of the drivetrain. With CNG-powered engines in particular, however, methane and other tailpipe emissions of climate gases and pollutants must also be minimized. This is possible in particular through efficient exhaust gas aftertreatment and an effective operating strategy of the powertrain. This publication presents measurement results that examine the critical aspect of cold
Noone, Patrick, Herold, Tim, Beidl, Christian
TOC99-06-03-0TOC06/21/2024
TOC
Tobolski, Sue
Methane Conversion in Stoichiometric Natural Gas Engine Exhaust2024-01-263204/09/2024
Stoichiometric natural gas (CNG) engines are an attractive solution for heavy-duty vehicles considering their inherent advantage in emitting lower CO2 emissions compared to their Diesel counterparts. Additionally, their aftertreatment system can be simpler and less costly as NOx reduction is handled simultaneously with CO/HC oxidation by a Three-Way Catalyst (TWC). The conversion of methane over a TWC shows a complex behavior, significantly different than non-methane hydrocarbons in stoichiometric gasoline engines. Its performance is maximized in a narrow A/F window and is strongly affected by the lean/rich cycling frequency. Experimental and simulation results indicate that lean-mode efficiency is governed by the palladium’s oxidation state while rich conversion is governed by the gradual formation of carbonaceous compounds which temporarily deactivate the active materials. Lean/rich cycling around stoichiometry enables a higher CH4 oxidation as the oxygen storage seems to balance the
Karamitros, Dimitrios, Ibraimova, Adjer, Konstantinidis, Konstantinos, Koltsakis, Grigorios, Choi, Sungmu, Cho, Jiho
Post-Oxidation Phenomena as a Thermal Management Strategy for Automotive After-Treatment Systems: Assessment by Means of 3D-CFD Virtual Developmen t2024-01-262904/09/2024
The target of the upcoming automotive emission regulations is to promote a fast transition to near-zero emission vehicles. As such, the range of ambient and operating conditions tested in the homologation cycles is broadening. In this context, the proposed work aims to thoroughly investigate the potential of post-oxidation phenomena in reducing the light-off time of a conventional three-way catalyst. The study is carried out on a turbocharged four-cylinder gasoline engine by means of experimental and numerical activities. Post oxidation is achieved through the oxidation of unburned fuel in the exhaust line, exploiting a rich combustion and a secondary air injection dedicated strategy. The CFD methodology consists of two different approaches: the former relies on a full-engine mesh, the latter on a detailed analysis of the chemical reactions occurring in the exhaust line. The coupling between experimental data and simulation results provides a complete assessment of the investigated
Barillari, Loris, Pipolo, Mario, Della Torre, Augusto, Montenegro, Gianluca, Onorati, Angelo, Vacca, Antonino, Chiodi, Marco, Kulzer, André
Ultra-Downsizing of ICEs Based on True Atkinson Cycle Implementations. Thermodynamic Analysis and Comparison on the Indicated Fuel Conversion Efficiency of Atkinson and Classical ICE Cycles2024-01-209604/09/2024
Ultra-Downsizing (UD) was introduced as an even higher level of downsizing for Internal Combustion Engines ICEs, see [2] SAE 2015-01-1252. The introduction of Ultra Downsizing (UD) aims to enhance the power, efficiency, and sustainability of ICEs while maintaining the thermal and mechanical strain within acceptable limits. The following approaches are utilized: 1 True Atkinson Cycles are implemented utilizing an asymmetrical crank mechanism called Variable Compression and Stroke Ratios (VCSR). This mechanism allows for extended expansion stroke and continuous adjustment of the Volumetric Compression Ratio (VCR). 2 Unrestricted two or more stage high-pressure turbocharging and intensive intercooling: This setup enables more complete filling of the cylinder and reduces the compression work on the piston, resulting in higher specific power and efficiency. 3 The new Load Control (LC) approach is based to continuous VCR adjustment. By adjusting the VCR without resorting to excessive
Gheorghiu, Victor
Sulfur Impact on Methane Steam Reforming over the Stoichiometric Natural Gas Three-Way Catalyst2024-01-263304/09/2024
The steam reforming of CH4 plays a crucial role in the high-temperature activity of natural gas three-way catalysts. Despite existing reports on sulfur inhibition in CH4 steam reforming, there is a limited understanding of sulfur storage and removal dynamics under various lambda conditions. In this study, we utilize a 4-Mode sulfur testing approach to elucidate the dynamics of sulfur storage and removal and their impact on three-way catalyst performance. We also investigate the influence of sulfur on CH4 steam reforming by analyzing CH4 conversions under dithering, rich, and lean reactor conditions. In the 4-Mode sulfur test, saturating the TWC with sulfur at low temperatures emerges as the primary cause of significant three-way catalyst performance degradation. After undergoing a deSOx treatment at 600 °C, NOx conversions were fully restored, while CH4 conversions did not fully recover. Experimental data under fixed lambda conditions reveal that sulfur stored on the catalyst leads to
Kim, Mi-Young, Dadi, Karthik Venkata, Gong, Jian, Kamasamudram, Krishna
Improved Coated Gasoline Particulate Filters for China 7 and US Tier 4 Legislations2024-01-238704/09/2024
The impending emission regulations in both China (CN7) and the United States (Tier 4) are set to impose more stringent emission limits on hydrocarbons (HC), carbon monoxide (CO), nitrogen oxides (NOx), and particulate matter (PM). CN7 places particular emphasis on reducing particulate number (PN) thresholds, while the forthcoming United States Tier 4 legislation is primarily concerned with reducing the allowable particulate matter (PM) to an assumed limit of 0.5 mg/mile. Given the more stringent constraints on both PN and PM emissions, the development of enhanced aftertreatment solutions becomes imperative to comply with these new regulatory demands. Coated Gasoline Particulate Filters (cGPFs) play a pivotal role as essential components for effective PN and PM abatement. These filters are typically deployed in one of two configurations: close-coupled to the turbocharger positioned downstream of a primary three-way catalyst (TWC) or located further downstream of the exhaust system in an
Schoenhaber, Jan, Kawashima, Shota, Gotthardt, Meike, Schühle, Johannes
A Three-Way Catalyst Model for a Bio-Methane Heavy-Duty Engine: Characterization at Different Lambda2024-01-208404/09/2024
Given the spread of natural gas engines in low-term toward decarbonization and the growing interest in gaseous mixtures as well as the use of hydrogen in Heavy-Duty (HD) engines, appropriate strategies are needed to maximize thermal efficiency and achieve near-zero emissions from these propulsor systems. In this context, some phenomena related to real-world driving operations, such as engine cut-off or misfire, can lead to inadequate control of the Air-to-Fuel ratio, key factor for Three-Way Catalyst (TWC) efficiency. Goal of the present research activity is to investigate the performance of a bio-methane-fueled HD engine and its Aftertreatment System (ATS), consisting of a Three-Way Catalyst, at different Air-to-Fuel ratio. An experimental test bench characterization, in different operating conditions of the engine workplan, was carried out to evaluate the catalyst reactivity to a defined pattern of the Air-to-Fuel ratio. Through the detection of key performance parameters and
Di Maio, Dario, Guido, Chiara, Napolitano, Pierpaolo, Beatrice, Carlo
Effective Utilization of Pt Catalyst in Three-Way Catalytic System by Employing Calcined Ceria with Alumina2024-01-213304/09/2024
To satisfy the stringent regulations for exhaust gas emissions from gasoline-powered vehicles, large amounts of Rh and Pd have often been employed in three-way catalysts (TWCs) as the main active components. On the other hand, Pt-based TWCs are not often used in gasoline vehicles because Pt is readily sintered by its exhaust gases at approximately 1000 °C [1, 2]. In general, Pt-based TWCs must be located away from large thermal loads to maintain the active sites for gas purification. Based on this background, we previously reported that employing a small amount of CeO2 calcined at 1000 °C (cal-CeO2) in Pt-based TWCs was one of the most effective approaches for improving the catalytic activity without increasing the amount of Rh and Pd [3]. The effect of cal-CeO2 was attributed to the higher redox performance and Pt dispersion derived from the strong interactions between Ce and Pt. Therefore, the resulting Pt-based TWCs exhibited high catalytic performance, despite the low specific
Morita, Itaru, Tanaka, Hiroki, Saeki, Shohei, Isayama, Akihiro, Iwashina, Katsuya, Nagao, Yuki, Endo, Yoshinori, Wakabayashi, Takashi, Haneda, Masaaki
Experimental Emission Characteristics Study of Ethanol-Gasoline Fuel Blends on a GDI Engine with a Three-Way Catalyst2024-26-015501/16/2024
Ethanol-gasoline blended fuels have been widely implemented in Indian markets followed by the Govt of India’s road map as ethanol reduces life-cycle greenhouse gas emissions and improves anti-knock performance. However, effects of Ethanol Blending on engine out emissions characteristics including particulates from gasoline direct injection (GDI) engine remains under development and investigation. In this study the effect of ethanol blended gasoline fuels with two blending rates 10% and 20% (v/v %) on catalyst conversion efficiencies and emissions on a 1.2 litre 3-cylinder turbo GDI engine is investigated. The addition of ethanol to gasoline fuel enhances the Octane rating (RON) of the blended fuels, oxygen content and changes Reid vapor pressure (RVP). The influence of lambda biasing, and lambda trim controller has been tested. The approach for calibration was adopted based on achieving the target pollutant conversion efficiencies. Test bench results indicated that with E10 blend all
R, Navaneetha Kannan, S, Easwar Ram, S, Satish Kumar, Karthi, Ramanathan, Ramakrishnan, Muthu
Three Way Catalyst with Faster Light-Off Substrates – A Promising Approach to Reduce Tailpipe Emissions2024-26-014201/16/2024
The ever-tightening regulation norms across the world emphasize the magnitude of the air pollution problem. The decision to leapfrog from BS4 to BS6 – with further reduction in emission limits -showed India’s commitment to clean up its atmosphere. The overall cycle emissions were reduced significantly to meet BS6 targets [1]. However, the introduction of RDE norms in BS6.2 [1] demanded further reduction in emissions under real time operating conditions – start-stop, hard acceleration, idling, cold start – which was possible only through strategies that demanded a cost effective yet robust solutions. The first few seconds of the engine operation after start contribute significantly to the cycle gaseous emissions. This is because the thermal inertia of the catalytic converter restricts the rate at which temperature of the catalyst increases and achieves the desired “light-off” temperature. The challenge becomes more prominent in the turbocharged engines (where some part of exhaust heat
Kale, Vishal Maruti, M, Ravisankar, Hosur, Viswanatha, Sridhar, S, Bhimavarapu, Aditya, Lende, Nilesh Ashok, Rose, Dominik, Tao, Tinghong
A Mechanism to Maintain Negative Crankcase Pressure in Turbocharged Gas Engine to Reduce Particulate Number to Meet Euro-VI Emission Regulation2024-26-014501/16/2024
Emissions regulation continually drives the automotive industry to innovate and develop. This pushes to introduce mechanism to maintain negative crankcase pressure in gas engine to meet this changing regulation. The way a turbocharger is used, to meet engine performance, can impact the pressure balance over the compressor and turbine end seals. This pressure difference can allow oil to leak through turbocharger seals. In normal engine operating condition the pressure in the turbocharger end housings is higher than the bearing housing and oil/gas flows into the bearing housing, through the oil drain to the crankcase. Under certain operating conditions, such as low idle and motoring, this pressure difference can be reversed with a higher bearing housing pressure than the pressure behind the turbine wheel. Under this condition oil will flow out of the bearing housing to the recess behind the turbine wheel, will increase the exhaust tail pipe emission, high oil consumption and damages the
R, Mahesh Bharathi
Characterization of an Integrated Three-Way Catalyst/Lean NOx Trap System for Lean Burn SI Engines2023-01-165810/31/2023
The push for environmental protection and sustainability has led to strict emission regulations for automotive manufacturers as evident in EURO VII and 2026 EPA requirements. The challenge lies in maintaining fuel efficiency and simultaneously reducing the carbon footprint while meeting future emission regulations. Alcohol (primarily methanol, ethanol, and butanol) and ether (dimethyl ether) fuels, owing to their comparable energy density to existing fuels, the comparative ease of handling, renewable production, and suitable emission characteristics may present an attractive drop-in replacement, fully or in part as an additive, to the gasoline/diesel fuels, without extensive modifications to the engine geometry. Additionally, lean and diluted combustion are well-researched pathways for efficiency improvement and reduction of engine-out emissions of modern engines. Modern spark ignition (SI) engines typically employ various in-cylinder emission reduction techniques along with a three
Sandhu, Navjot Singh, Leblanc, Simon, Yu, Xiao, Reader, Graham, Zheng, Ming
Ammonia Emissions from Combustion in Gasoline Engines2023-01-165510/31/2023
Forthcoming worldwide emissions regulations will start regulating ammonia emissions from light duty vehicles. At present, most light duty vehicles are powered by gasoline spark ignition engines. Sources of ammonia emission from such engines can be in-cylinder reactions (i.e. combustion) or downstream reactions across aftertreatment devices, particularly three-way catalysts. The latter has been known to be a major source of ammonia emissions from gasoline vehicles and has been extensively investigated. The former (combustion), less so, and thus is the subject of this work. A two-zone thermodynamic spark ignition engine model with a comprehensive chemical kinetics framework (C3MechV3.3 mechanism), after being validated against experimental ammonia emissions data, is used to study ammonia formation during combustion. Reaction pathways responsible for its generation are analysed and the effects of changing the following engine operational and combustion parameters are explored: engine load
Bajwa, Abdullah, Shankar, Varun, Leach, Felix
Improvement of the EGR Dilution Tolerance in Gasoline Engines by the Use of a HSASI Pre-Chamber Spark Plug2023-01-180510/24/2023
Charge dilution in gasoline engines reduces NOx emissions and wall heat losses by the lower combustion temperature. Furthermore, under part load conditions de-throttling allows the reduction of pumping losses and thus higher engine efficiency. In contrast to lean burn, charge dilution by exhaust gas recirculation (EGR) under stoichiometric combustion conditions enables the use of an effective three-way catalyst. A pre-chamber spark plug with hot surface-assisted spark ignition (HSASI) was developed at the UAS Karlsruhe to overcome the drawbacks of charge dilution, especially under part load or cold start conditions, such as inhibited ignition and slow flame speed, and to even enable a further increase of the dilution rate. The influence of the HSASI pre-chamber spark plug on the heat release under EGR dilution and stoichiometric conditions was investigated on a single-cylinder gasoline engine. The performance of the HSASI spark plug was compared with a passive pre-chamber spark plug
Holzberger, Sascha, Kettner, Maurice, Kirchberger, Roland
Exhaust Aftertreatment Technologies for PN Reduction of Motorcycles2023-01-184610/24/2023
The objective of this experimental investigation was to analyze the effect of various exhaust gas aftertreatment technologies on particulate number emissions (PN) of an MPFI EU5 motorcycle. Specifically, three different aftertreatment strategies were compared, including a three-way-catalyst (TWC) with LS structure as the baseline, a hybrid catalyst with a wire mesh filter, and an optimized gasoline particulate filter (GPF) with three-way catalytic coating. Experimental investigations using the standard test cycle WMTC performed on a two-wheeler chassis dynamometer, while the inhouse particulate sampling system was utilized to gather information about size-dependent filtering efficiency, storage, and combustion of nanoparticles. The particulate sampling and measuring system consist of three condensation particle counters (CPCs) calibrated to three different size classes (SPN4, SPN10, SPN23). The study revealed that all three aftertreatment technologies were effective in reducing PN from
Schurl, Sebastian, Bonifer, Marcus, Schmidt, Stephan, Bretterklieber, Niko, Joshi, Pragati
Effects of Different Driving Behavior during Actual Road Driving on Ammonia Emissions from Gasoline Vehicles2023-32-009509/29/2023
Three-way catalysts are used in gasoline vehicles for simultaneous purifying nitrogen oxide, carbon monoxide, and hydrocarbon in recent years. However, the reduction of ammonia emission generated in the three-way catalyst is pressing issue. In EURO 7, ammonia will also be subject to the Real Driving Emissions regulation, and its emissions must be reduced. Previous studies have shown that ammonia emissions are higher under fuel-rich conditions, suggesting that differences in driving behavior have a significant impact on ammonia emissions in real-world driving, which includes various driving environments. In this study, driving tests were conducted on a direct- injection gasoline vehicle equipped with a three-way catalyst and Portable Emission Measurement System and Sensor-based Emission Measurement System to investigate the actual ammonia emissions on actual roads. Sensor-based Emission Measurement System includes the system that can measure ammonia and nitrogen monoxide concentrations
Sato, Susumu, Chen, Jiaxin, Eang, Chanpaya, Tanaka, Kotaro, Tange, Takeshi
Development of Detailed Surface Reaction Mechanism of CO/ NO/ O 2 System for Three Way Catalyst Based on Gaseous and Surface Species Analyses2023-32-012209/29/2023
In this study, we determined the detailed reaction mechanism of CO/NO/O2 for automotive three way catalysts. The N2O formation process obtained from measurements of the reaction properties and the formation process of adsorbed NCO species obtained from surface analysis of platinum group metals were added to a previous detailed surface reaction mechanism. The computational accuracy of the developed reaction mechanism was verified by the one-dimensional simulation software BOOST, and it was found to be sufficient for any combination of platinum group metals and gas concentrations.
Matsumoto, Yuhei, Shimokuri, Daisuke, Miyoshi, Akira, Hinokuma, Satoshi, Murakami, Hiroshi, Kawano, Michiharu
A Study of Multi-Functional Membrane Filters made of Fine Catalyst Particles2023-32-012509/29/2023
A multi-functional membrane filter was developed through deposition of agglomerated Three-Way Catalyst particles with a size of 1 ~ 2 microns on the conventional bare particulate filter. The filtration efficiency reaches almost 100 % from the beginning of soot trapping with a low pressure drop and both reductions of NO and CO emission were achieved.
Hanamura, Katsunori, Fujii, Shinpei, Teerapat, Suteerapongpun
Potentials of Air Path Variabilities and Water Injection in HD Gas Engines2023-24-012008/28/2023
The transportation sector, and commercial vehicles in particular, play an important role in global CO2 emissions. For this reason, the EU recently decided to reduce CO2 emissions from commercial vehicles by 30% until 2030. One alternative to conventional diesel propulsion is the usage of stoichiometric natural gas combustion. Due to the lowered C/H ratio and the cost effective exhaust after treatment (EAT) in form of a three way catalyst (TWC), less CO2 is emitted and it is possible to comply even with most stringent NOX legislations. However, the stoichiometric combustion of natural gas has also disadvantages. In particular, the throttling and retarded 50 % mass fuel burned (MFB50) positions due to knocking lead to efficiency losses. One way to minimize these is the usage of exhaust gas re-circulation (EGR), Miller cycle and water injection. The reduced knocking tendency allows the geometric compression ratio to be increased further, which leads to an additional efficiency advantage
Betz, Marius, Eilts, Peter
Improvement of Post-Oxidation for Low-Emission Engines through 3D-CFD Virtual Development2023-24-010708/28/2023
There is a growing need for low-emissions concepts due to stricter emission regulations, more stringent homologation cycles, and the possibility of a ban on new engines by 2035. Of particular concern are the conditions during a cold start, when the Three-Way Catalyst is not yet heated to its light-off temperature. During this period, the catalyst remains inactive, thereby failing to convert pollutants. Reducing the time needed to reach this temperature is crucial to comply with the more stringent emissions standards. The post oxidation by means of secondary air injection, illustrated in this work, is a possible solution to reduce the time needed to reach the above-mentioned temperature. The strategy consists of injecting air into the exhaust manifold via secondary air injectors to oxidize unburned fuel that comes from a rich combustion within the cylinder. This strategy can be implemented without major modifications to the engine's hardware or control system, making it an attractive
Pipolo, Mario, Kulzer, Andre, Chiodi, Marco, Moriyoshi, Yasuo
Pre-investigations on Reactive Exhaust Gas Recirculation for a Naturally Aspirated Cogeneration Gas Engine2023-01-121206/26/2023
Given its ability to be combined with the three-way catalyst, the stoichiometric operation is significantly more attractive than the lean-burn process, when considering the increasingly severe NOx limit for cogeneration gas engines in Germany. However, the high temperature of the stoichiometric combustion results in increased wall heat losses, restricted combustion phasings (owing to knock tendency) and thus efficiency penalties. To lower the temperature of the stoichiometric combustion and thus improve the engine efficiency, exhaust gas recirculation (EGR) is one of the most effective means. Nevertheless, the dilution with EGR has much lower tolerance level than with excess air, which leads to a consequent drop in the thermal efficiency. In this regard, reducing the water vapor concentration in the recirculated exhaust gas and increasing the EGR reactivity are two potential measures that may extend the mixture dilution limit and result in engine efficiency benefits. Here, the reactive
Beltaifa, Youssef, Kettner, Maurice, Eilts, Peter, Ruchel, Bosse, Fröstl, Sebastian
Comparability of Hot-Wire Estimates of Liquid Water Content in SLD Conditions2023-01-142306/15/2023
Future compliance to FAA 14 CFR Part 25 and EASA CS-25 Appendix O conditions has required icing wind tunnels to expand their cloud simulation envelope, and demonstrate accurate calibration of liquid water content and droplet particle size distributions under these conditions. This has led to a renewed community interest in the accuracy of these calibrations, and the potential inter-facility bias due to the choice of instrumentation and processing methods. This article provides a comparison of the response of various hot-wire liquid water content instruments under Appendix C and supercooled large droplet conditions, after an independent similar analysis at other wind tunnel facilities. The instruments are being used, or are under consideration for use, by facilities collaborating in the ICE GENESIS program. For droplet median volume diameters (MVDs) between about 15 and 250 μm, cylindrical hot wire LWC sensors were found to consistently and increasingly under-read measurements from
Esposito, Biagio M., Orchard, David, Lucke, Johannes, Nichman, Leonid, Bliankinshtein, Natalia, Lilie, Lyle, Catalano, Pietro, D'Aniello, Francesco, Strapp, J. Walter
Snow Particle Characterization. Part A: Statistics of Microphysical Properties of Snow Crystal Populations from Recent Observations Performed during the ICE GENESIS Project2023-01-149206/15/2023
Measurements in snow conditions performed in the past were rarely initiated and best suited for pure and extremely detailed quantification of microphysical properties of a series of microphysical parameters, needed for accretion modelling. Within the European ICE GENESIS project, a considerable effort of natural snow measurements has been made during winter 2020/21. Instrumental means, both in-situ and remote sensing were deployed on the ATR-42 aircraft, as well as on the ground (ground station at ‘Les Eplatures’ airport in the Swiss Jura Mountains with ATR-42 overflights). Snow clouds and precipitation in the atmospheric column were sampled with the aircraft, whereas ground based and airborne radar systems allowed extending the observations of snow properties beyond the flight level chosen for the in situ measurements. Overall, five flight missions have been performed at different numerous flight levels (related temperature range from -10°C to +2°C) beyond the ‘Les Eplatures’ airport
Jaffeux, Louis, Schwarzenboeck, Alfons, Coutris, Pierre, Febvre, Guy, Dezitter, Fabien, Aguilar, Boris, billault-Roux, Anne-claire, Grazioli, Jacopo, Berne, Alexis, Köbschall, Kilian, Jorquera, Susana, Delanoe, Julien
Experimental and Numerical Investigation of a Particle Filter Technology for NG Heavy-Duty Engines2023-01-036804/11/2023
The forthcoming introduction of the EURO VII regulation requires urgent strategies and solutions for the reduction of sub-23 nm particle emissions. Although they have been historically considered as particulate matter-free, the high interest for Natural Gas (NG) Heavy-Duty engines in the transport sector, demands their compliance with the new proposed regulations. In order to obtain high conversion of gas pollutants and a strong abatement of the emitted particles, the use of Particle Filters in NG aftertreatment (CPF) in conjunction with the Three-Way Catalyst (TWC) may represent an attractive and feasible solution. Performances of a cordierite filter were explored through an extensive experimental campaign both in Steady-State conditions and during transient engine maneuvers that involved a whole analysis of the emitted particles in terms of number and mass. This investigation assessed different emitted particle reduction efficiency, highlighting distinct levels between no-load (low
Di Maio, Dario, Guido, Chiara, Napolitano, Pierpaolo, Beatrice, Carlo, Golini, Stefano
Analysis and Optimization of Metallic Based Substrates for After-Treatment System by Means of Full-Scale CFD Simulations and Experiments2023-01-036904/11/2023
The tightening trend of regulations on the levels of admitted pollutant emissions has given a great spur to the research work in the field of combustion and after-treatment devices. Despite the improvements that can be applied to the development of the combustion process, pollutant emissions cannot be reduced to zero; for this reason, the aftertreatment system will become a key component in the path to achieving near-zero emission levels. This study focuses on the numerical analysis and optimization of different metallic substrates, specifically developed for three-way catalyst (TWC) and Diesel oxidation catalyst (DOC) applications, to improve their thermal efficiency by reducing radial thermal losses through the outer mantle. The optimization process relies on computational fluid dynamics (CFD) simulations supported by experimental measurements to validate the numerical models carried out under uncoated conditions, where chemical reactions do not occur. Full-scale three-dimensional
Sartirana, Andrea, Montenegro, Gianluca, Della Torre, Augusto, Onorati, Angelo, Pace, Lorenzo, Zaldua-Moreno, Naroa
High Cell Density Flow Through Substrate for New Regulations2023-01-035904/11/2023
This paper, written in collaboration with Ford, evaluates the effectiveness of higher cell density combined with higher porosity, lower thermal mass substrates for emission control capability on a customized, RDE (Real Driving Emissions)-type of test cycle run on a chassis dynamometer using a gasoline passenger car fitted with a three-way catalyst (TWC) system. Cold-start emissions contribute most of the emissions control challenge, especially in the case of a very rigorous cold-start. The majority of tailpipe emissions occur during the first 30 seconds of the drive cycle. For the early engine startup phase, higher porosity substrates are developed as one part of the solution. In addition, further emission improvement is expected by increasing the specific surface area (GSA) of the substrate. This test was designed specifically to stress the cold start performance of the catalyst by using a short, 5 second idle time preceding an aggressive, high exhaust mass flowrate drive cycle. The
Nakasumi, Hayaki, Kawakami, Akifumi, Ohara, Etsuji, sugimoto, Kentaro, Hibi, Noriyuki, Asako, Tsuyoshi, Kato, Kyohei, Anoop, Reghunathan-Nair, Affan, Syed, Thanasiu, Eva, Lambert, Christine K., Hubbard, Carolyn
Effect of Split-Injection Strategies on Engine Performance and Emissions under Cold-Start Operation2023-01-023604/11/2023
The recently concluded partnership for advancing combustion engines (PACE) was a US Department of Energy consortium involving multiple national laboratories focused on addressing key efficiency and emission barriers in light-duty engines. Generation of detailed experimental data and modeling capabilities to understand and predict cold-start behavior was a major pillar in this program. Cold-start, as defined by the time between first engine crank and three-way catalyst light-off, is responsible for a large percentage of NOx, unburned hydrocarbon, and particulate matter emissions in light-duty engines. Minimizing emissions during cold-start is a trade-off between achieving faster three-way catalyst light-off, and engine out emissions during that period. In this study, engine performance, emissions, and catalyst warmup potential were monitored while the engine was operated using a single direct injection (baseline case) as well as a two-way-equal-split direct injection strategy. These
Jatana, Gurneesh S., Dal Forno Chuahy, Flavio, Szybist, James
Experimental and Modeling Study on the Thermal Aging Impact on the Performance of the Natural Gas Three-Way Catalyst2023-01-037504/11/2023
The prediction accuracy of a three-way catalyst (TWC) model is highly associated with the ability of the model to incorporate the reaction kinetics of the emission process as a lambda function. In this study, we investigated the O2 and H2 concentration profiles of TWC reactions and used them as critical inputs for the development of a global TWC model. We presented the experimental data and global kinetic model showing the impact of thermal degradation on the performance of the TWC. The performance metrics investigated in this study included CH4, NOx, and CO conversions under lean, rich, and dithering light-off conditions to determine the kinetics of oxidation reactions and reduction/reforming/water-gas shift reactions as a function of thermal aging. The O2 and H2 concentrations were measured using mass spectrometry to track the change in the oxidation state of the catalyst and to determine the mechanism of the reactions under these light-off conditions. The experimental data indicate
Kim, Mi-Young, Dadi, Rama Krishna, Gong, Jian, Kamasamudram, Krishna
Model-Free State Estimation Using Subspace Identification and Kalman Filter2023-01-036504/11/2023
The model-based design is very much prominent in the vehicle level control system design and state estimation algorithms. It gives the edge to understand and interpret the dynamic systems. Three-way catalytic converter is a thermo-chemical device to convert the toxic oxides into carbon dioxide and water vapor, during this conversion reactions it generates the heat over the catalyst surface. Detailed chemical and thermal model of the catalyst will be able to predict the conversion efficiency, state of stored oxygen (SoX) and oxygen storage capacity (OSC). As the catalyst get aged, the reaction rates of conversion reactions deteriorate, in results the temperature dynamics also varies which wanes the exothermic heat. In this work, a novel perspective is presented to capture the behavior of SoX and health of the catalytic converter using thermal model analysis of TWC. An equivalent second order multi input single output (MISO) linear sub-space model is identified for the complex detailed
Mandloi, Deepak, Sahu, Prachi, Bagade, Monika Jayprakash, Das, Himadri
Development of 50% Thermal Efficiency S.I. Engine to Contribute Realization of Carbon Neutrality2023-01-024104/11/2023
To prevent global warming, many countries are making efforts to reduce CO2 emissions toward achieving 2050 carbon neutrality. In order to reduce CO2 concentration quickly, in addition to spread of renewable energy and expansion of BEV, it is also important to reduce CO2 emissions by improving thermal efficiency of ICE (internal combustion engine) and utilizing carbon neutral fuels such as synthetic fuels and biofuels. It is well known that lean burn is an effective technology to increase thermal efficiency of engine highly. However, since NOx emission from lean burn engine cannot be reduced with three-way catalyst, there have been issues such as complicated system configuration due to the addition of NOx reduction catalyst or limiting lean operation to narrow engine speed and load in order to meet emission regulation of each country. This paper introduces super lean burn engine with over lambda 2.5 that achieves both high thermal efficiency and significantly low NOx emission in order
Kimura, Koshiro, SAKAI, Hiroyuki, Omura, Tetsuo, Takahashi, Daishi
A Method to Reduce Cold Start Emissions while Shortening Fast Idle Catalyst Light-off Time2023-01-024704/11/2023
For vehicles with internal combustion engines, tailpipe emissions heavily rely on the aftertreatment system, typically a catalytic converter. Modern three-way catalysts (TWC) can very effectively convert the unburnt hydrocarbons (HC), CO, and NOx into non-harmful gases such as H2O, CO2, and N2 when the catalyst brick reaches a relatively high temperature. However, before that catalyst light-off temperature is reached, the emissions conversion efficiency is low, leading to high tailpipe emissions. Due to this light-off temperature requirement of the catalytic converter, the emissions from the engine cold-start period contributes a significant portion of vehicle overall emissions. One of the major reasons for high emissions during cold start is low combustion chamber wall temperatures, lower than the initial boiling temperature of gasoline fuel. This results in fuel film formation, and significantly incomplete evaporation prior to combustion. In this study, an approach to increase the
Zhu, Shengrong, Hollowell, Jeffrey, Ha, Kyoung-Pyo, Fantin, Nicholas, Shirley, Mark
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