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Technical Paper

Improved Coated Gasoline Particulate Filters for China 7 and US Tier 4 Legislations

2024-04-09
2024-01-2387
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.
Technical Paper

Advanced Aftertreatment System Meeting Future HD CNVII Legislation

2024-04-09
2024-01-2379
Options for CNVII emission legislation are being widely investigated in a national program organized by China Vehicle Emission Control Center (VECC) since early 2020. It is foreseen that this possibly last legislation in China will have more stringent emission requirements compared to CNVI, including among other changes especially a further reduction of nitrogen oxide (NOx), inclusion of nitrous oxide (N2O) and sub-23 nm particle number (PN). This study investigates the technical feasibility to fulfill a CNVII emission legislation scenario, based on a modified CNVI 8 L engine operating under both cold and hot World Harmonized Transient Cycle (WHTC) and Low Load Cycle (LLC).
Technical Paper

Performance Evaluation Study to Optimize the NOx Conversion Efficiency of SDPF Catalyst for BS6 RDE/OBD2 Engine Application

2024-01-16
2024-26-0161
To meet future emission levels, the automotive industry is trying to reduce tailpipe emissions through both possible pathways, i.e. emission from engines as well as and the development of novel catalytic emission control concepts. The present study will focus on the close coupled SCR on Filter commonly known as SDPF which is a main pathway to reduce NOx along with particulate mass and number for light duty passenger cars and sport utility vehicles for BS 6 RDE/OBD 2 and future legislation like BS-7. The SDPF is a challenging technology as it is critical component in exhaust after treatment system involving in NOx and PM/PN reductions hence careful optimization of this technology is necessary in terms of space velocity requirements, temperature, feed NOx emission levels, particulate mass and ash holding capacities, NH3 storage on the SDPF, and back pressure.
Journal Article

Catalysts for Post Euro 6 Plug-In Hybrid Electric Vehicles

2020-04-14
2020-01-0354
Due to benefits from the use of electric power, Hybrid Electric Vehicles (HEVs) and Plug-in Hybrid Electric Vehicles (PHEVs) are regarded to be superior over conventional Internal Combustion Engine (ICE) only vehicles in fuel economy and emissions. However, recent studies find out that this is not always true. On certain conditions, hybrid vehicles can be even more polluted. In order to identify these challenges and develop catalysts to meet more stringent emission requirement in the future, e.g. Euro 7, for hybrid application, as a part of our xHEV project, this study includes exclusively extensive investigation on a latest Euro 6d temp Parallel PHEV.
Journal Article

The Thermodynamics of Exhaust Gas Condensation

2017-06-29
2017-01-9281
Water vapor is, aside from carbon dioxide, the major fossil fuel combustion by-product. Depending on its concentration in the exhaust gas mixture as well as on the exhaust gas pressure, its condensation temperature can be derived. For typical gasoline engine stoichiometric operating conditions, the water vapor dew point lies at about 53 °C. The exhaust gas mixture does however contain some pollutants coming from the fuel, engine oil, and charge air, which can react with the water vapor and affect the condensation process. For instance, sulfur trioxide present in the exhaust, reacts with water vapor forming sulfuric acid. This acid builds a binary system with water vapor, which presents a dew point often above 100 °C. Exhaust composition after leaving the combustion chamber strongly depends on fuel type, engine concept and operation point. Furthermore, the exhaust undergoes several chemical after treatments.
Technical Paper

Impact of European Real-Driving-Emissions Legislation on Exhaust Gas Aftertreatment Systems of Turbocharged Direct Injected Gasoline Vehicles

2017-03-28
2017-01-0924
Recently, the European Union has adopted a new regulation on Real-Driving-Emissions (RDE) and also China is considering RDE implementation into new China 6 legislation. The new RDE regulation is focused on measuring nitrogen oxides (NOx) and particulate number (PN) emissions of both light-duty gasoline and diesel vehicles under real world conditions. A supplemental RDE test procedure was developed for European type approval, which includes on-road testing with cars equipped with portable emission measurement systems (PEMS). This new regulation will significantly affect the engine calibrations and the exhaust gas aftertreatment. In this study the impact of the new RDE regulation on two recent EU 6b certified turbocharged direct injected gasoline vehicles has been investigated. A comparison of several chassis dyno drive cycles with two new defined on-road RDE cycles was performed.
Technical Paper

Synthetic Gas Bench (SGB) Tests Simulating Real and Dynamic Driving Conditions: A New and Cost Attractive Method for TWC Evaluation

2015-04-14
2015-01-1066
The introduction of vehicle emission and fuel economy standards (CO2) accelerates the introduction of new platform and powertrain combinations into the market place. All of these combinations will require unique exhaust gas aftertreatment systems that comply with the current emission legislation. The optimization of each unique aftertreatment solution requires the proper application of catalyst technologies at the lowest PGM concentrations. The optimization process needs to be fast, reliable, realistic and cost attractive. It is arguable that performing the aftertreatment optimization on a chassis dynamometer is variable, time consuming and expensive. This work demonstrates how a synthetic gas bench (SGB) can be used to simulate stoichiometric engine emissions and aftertreatment performance. The SGB procedure duplicates the vehicle NEDC engine-out emissions and catalyst heat-up profiles.
Technical Paper

Advanced TWC Technology to Cover Future Emission Legislations

2015-04-14
2015-01-0999
The new emission regulations in Europe, EU 6 will promulgate more realistic driving conditions with more stringent HC, CO, NOx and particulate emissions. This legislation will also include the WLTP (Worldwide harmonized Light vehicles Test Procedure) cycle for CO2 measurements and a new requirement called “Real-Driving-Emissions” (RDE) as well. The RDE requirement is to ensure modern vehicles comply with the legislation under all conditions of normal driving. More robust aftertreatment solutions are needed to meet these new requirements. This work introduces an improved three-way catalyst (TWC) for gasoline engines for these new regulations. It is tested under static and dynamic conditions and on several engines and vehicles with various drive cycles. It offers better thermal stability combined with lower backpressure than former TWC generations.
Journal Article

Development and Demonstration of LNT+SCR System for Passenger Car Diesel Applications

2014-04-01
2014-01-1537
The regulations for mobile applications will become stricter in Euro 6 and further emission levels and require the use of active aftertreatment methods for NOX and particulate matter. SCR and LNT have been both used commercially for mobile NOX removal. An alternative system is based on the combination of these two technologies. Developments of catalysts and whole systems as well as final vehicle demonstrations are discussed in this study. The small and full-size catalyst development experiments resulted in PtRh/LNT with optimized noble metal loadings and Cu-SCR catalyst having a high durability and ammonia adsorption capacity. For this study, an aftertreatment system consisting of LNT plus exhaust bypass, passive SCR and engine independent reductant supply by on-board exhaust fuel reforming was developed and investigated. The concept definition considers NOX conversion, CO2 drawback and system complexity.
Journal Article

Applicable Diesel Oxidation Catalyst for Multi-Diesel Exhaust System

2014-04-01
2014-01-1511
The diesel oxidation catalysts (DOC) having high purification performance to the exhaust gas at low temperatures were investigated. In this paper two main technological improvements from conventional DOC are shown. First is forming Pt/Pd composite particles in order to suppress sintering of precious metal under high thermal aging condition. This generating Pt/Pd composite and the effect were exemplified by TEM-EDS and XRD analysis. Second is adjusting electric charge of Pt/Pd surface to reduce interaction between Pt/Pd and carbon monoxide (CO) by modifying the support material components. Adjusting electric charge of Pt/Pd surface by applying new support material could cancel CO poisoning at Pt/Pd surface. Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS) studies suggested that improved support material is more suitable for CO oxidation at a low temperature based on the concept.
Technical Paper

Comprehensive Gasoline Exhaust Gas Aftertreatment, an Effective Measure to Minimize the Contribution of Modern Direct Injection Engines to Fine Dust and Soot Emissions?

2014-04-01
2014-01-1513
With the growing awareness about the presence of fine/ultra fine particulates in the ambient air and their negative impact on climate and health, some regions of the world have started to look closer at the contribution of road traffic. Since Gasoline engines, in particular when injecting fuel directly into the combustion chamber, proved to emit relevant numbers of particulates, even hardly visible, the growing share of Gasoline DI engines and their small size of particulate emissions is a concern. To address the same, the EU has already set limits for the particulate number with EU6 from 2015 onwards. The US considers setting challenging limits by particulate mass. Since mass of ultra fine particulates is very low and difficult to measure, experts investigate if a measurement by number might better address the particular concern. The implementation of a coated Particulate Filter enables meeting not only basic demands during traditional emission test cycles.
Technical Paper

Achieving BS-IV Emission Targets for Diesel Small Commercial Vehicle (SCV) with Close Coupled Advanced EnviCat® DOC and Coated PM Metalit® After - Treatment System

2013-01-09
2013-26-0054
Small Commercial Vehicle (SCV) is an emerging Commercial Vehicle (CV) segment both in India and throughout the world. Vehicles in this segment have diesel engine of capacity less than 1 l and GVW of less than 3.5 t. Normally for the CV, engines are tested on engine dynamometer for emission test, but SCV are tested on chassis dynamometer as they are classified as N1.1 class vehicles. Hence SCV have to follow same emission regulations as diesel passenger cars. The main challenge is to meet BS-IV NOx and PM emission target together with high torque optimization along with required durability targets. This paper addresses this challenge and reports the work carried out on an Indian SCV with 0.7 l naturally aspirated indirect injection diesel engine.
Technical Paper

Benefits of LS-Design™, a Structured Metal Foil for Two and Three Wheelers Catalyst Substrates, to Minimize Catalyst Volumes, PGM Loads and the Route Towards Low NOx Emissions

2011-10-06
2011-28-0042
More efficient and durable catalytic converters for the two- and three-wheeler industry in developing countries are required at an affordable cost to reduce vehicle emissions, to maintain them at a low level and therefore to participate in a cleaner and healthier environment. This particularly is true nowadays, because the demand and prices of Platinum Group Metal (PGM) for catalyst are continuously increasing due to i) the worldwide progressive implementation of motorcycles emission legislations similar to Euro 3 Stage requiring catalysts, ii) the need for non-road diesel vehicles to be equipped now with catalyst systems, and iii) the constant increase of the worldwide automobile market. A new generation of metallic substrates with structured foils for catalytic converters is proven to be capable of improving conversion behavior, even with smaller catalyst size.
Technical Paper

SCR and SCRi® as After-treatment Systems for Low CO2 and Low NOx Vehicles

2011-01-19
2011-26-0038
On one hand, latest worldwide emissions legislation developments aim to reduce NOx and Particulate Matter (PM) emissions of all diesel engines, while on the other hand lower fuel consumption diesel engines are still required for lower fleet average CO₂ emissions. As a consequence of the chosen CO₂ optimized combustion mode, the raw NOx emission increases and as such Selective Catalytic Reduction (SCR) technology will be the future choice for high efficiency NOx aftertreatment. This paper deals with SCR technology and its derivative SCRi® technology, when diesel particle reduction is required, especially for heavy-duty applications. Alongside the developed metal catalyst technologies, a complete SCR reducing agent dosing system is presented. Emission results gained with the SCR or SCRi® technologies on European commercial engines illustrate the potential of these technologies for conversion of NOx and PM emissions.
Technical Paper

Catalyst Technologies for Gasoline Engines with Respect to CO2 Reduction

2011-01-19
2011-26-0027
Besides the further reduction of the harmful gaseous emissions (HC, CO and NOx) to reach upcoming emission limits, the discussion on lowering the CO₂ emissions is omnipresent. From engine development point of view further optimization of the stoichiometric-operated gasoline engine as well as the introduction of lean-operated engines are the main development trend. The emission control system can support the engine development by dedicated catalyst technologies as presented in this paper. A new family of TWC technologies offers to tune the catalyst system to the engine performance and the back pressure requirement - which helps to reduce CO₂ emissions. In addition these technologies show improved performance in HC, CO, NOx light-off, and in CO and NOx conversions under dynamic conditions - this again can positively impact the CO₂ emissions as less harsh heating strategies for cold start is required.
Technical Paper

Gasoline HCCI/CAI on a Four-Cylinder Test Bench and Vehicle Engine - Results and Conclusions for the Next Investigation Steps

2010-05-05
2010-01-1488
Internal combustion engines with lean homogeneous charge and auto-ignition combustion of gasoline fuels have the capability to significantly reduce fuel consumption and realize ultra-low engine-out NOx emissions. Group research of Volkswagen AG has therefore defined the Gasoline Compression Ignition combustion (GCI®) concept. A detailed investigation of this novel combustion process has been carried out on test bench engines and test vehicles by group research of Volkswagen AG and IAV GmbH Gifhorn. Experimental results confirm the theoretically expected potential for improved efficiency and emissions behavior. Volkswagen AG and IAV GmbH will utilize a highly flexible externally supercharged variable valve train (VVT) engine for future investigations to extend the understanding of gas exchange and EGR strategy as well as the boost demands of gasoline auto-ignition combustion processes.
Technical Paper

Dynamic Model for the Selective Catalytic Reduction of NO with NH3 on Fe-Zeolite Catalysts

2008-04-14
2008-01-1323
Future NOx-emission standards for diesel engines imply an after treatment system, e.g. in the form of an NH3-SCR system. For the technical realization a sound understanding of the catalytic processes is mandatory. To gain this knowledge a model of the SCR of NO with NH3 on Fe zeolite catalysts has been developed on the basis of a transient test cycle. The model is able to map the performance of the catalyst both under steady state and transient conditions. As practical examples the model is used to parameterize lookup tables and to compare different formats of lookup tables in terms of suitability for a urea dosage system.
Technical Paper

Comparison of Different EGR Solutions

2008-04-14
2008-01-0206
This paper compares 4 different EGR systems by means of simulation in GT-Power. The demands of optimum massive EGR and fresh air rates were based on experimental results. The experimental data were used to calibrate the model and ROHR, in particular. The main aim was to investigate the influence of pumping work on engine and vehicle fuel consumption (thus CO2 production) in different EGR layouts using optimum VG turbine control. These EGR systems differ in the source of pressure drop between the exhaust and intake pipes. Firstly, the engine settings were optimized under steady operation - BSFC was minimized while taking into account both the required EGR rate and fresh air mass flow. Secondly, transient simulations (NEDC cycle) were carried out - a full engine model was used to obtain detailed information on important parameters. The study shows the necessity to use natural pressure differences or renewable pressure losses if reasonable fuel consumption is to be achieved.
Technical Paper

Diesel NOx-Storage Catalyst Systems for Tier 2 BIN5 Legislation

2008-04-14
2008-01-0766
NOx storage catalyst systems (or lean NOx trap, LNT) will most likely play an important role in meeting the future global Diesel emission standards. DaimlerChrysler introduced in 2006 the E 320 BLUETEC Diesel, which represents the first Clean Diesel car with NOx storage catalysts in North America [1]. The vast number of different applications result in a wide spectrum of different operating conditions for the LNT systems. Each of those different environments requires a fine-tuning of the catalyst's properties, particularly sulfur release properties and thermal durability. High average exhaust temperatures typical for a placement close to the engine require high thermal durability. Higher desulfation temperatures are acceptable in such a case since those temperatures are easier to achieve in such a configuration.
Technical Paper

PM Metalit® - A Continuously Regenerating Partial Flow Particulate Filter - Concept and Experience with Korean Retrofit Programme

2008-01-09
2008-28-0008
Emission legislations for the light / medium and heavy duty vehicles are becoming more and more stringent worldwide. Tightening of NOx and Particulate Matter (PM) limits further from Euro III to Euro IV levels has provoked the need of either controlling NOx from the engine measures and use PM control after-treatment devices such as Partial Flow Filters, or, controlling PM from the engine measures and use NOx control devices such as Selective Catalytic Reduction (SCR) systems. Manufacturers have adopted different strategies, depending upon the suitability, cost factors, infrastructure development and ease of maintenance of these systems. PM Metalit®, is a partial flow filter, which captures particulates coming out of the exhaust and re-generates on a continuous basis with the help of Nitrogen Dioxide (NO2) in the exhaust.
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