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Automobile Exhaust Emmision Control- A review

Manav Rachna International University-Sunny Bhatia
  • Technical Paper
  • 2019-28-2382
To be published on 2019-11-21 by SAE International in United States
Since the 20th century increase in the number of cars in the major cities is been a point of concern because of the toxic gasses being emitted from the engine of an automobile. These gasses are polluting the atmosphere and degrading the air to breathe. The main gasses responsible for the degradation of air quality are carbon monoxide, hydrocarbon and oxides of nitrogen. There is a necessity to find ways to reduce the pollution emitted into the atmosphere from the automobile. The source of emission is either evaporation from fuel tank or carburetor which is easy to be dealt with or harmful gasses due to improper combustion which is a concern for the environment. The two ways to reduce these emissions are, modification in the engine to minimize the production of harmful gases and to treat the harmful gasses emitted from the engine before blowing it into the atmosphere from the exhaust. Catalysts help to break harmful gasses into smaller compounds that are environment-friendly. The catalysts used are Rhodium Palladium and platinum, these make a…
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Design, Development and Analysis of Mullite Catalytic Converter for CI Engines

Kongu Engineering College-Selvakumar Pandiaraj, Dhamotharan Subbaiyan, Tamilvanan Ayyasamy, Sathishkumar Nagarajan
  • Technical Paper
  • 2019-28-0017
Published 2019-10-11 by SAE International in United States
Emissions of Hydrocarbon (HC), Carbon Monoxide (CO) and Oxides of Nitrogen (NOx) are the largest concerns for fossil fuel driven automotive vehicles. Catalytic converter is an important component in the selective catalytic reduction process. It oxidizes harmful CO and HC emission to CO2 and H2O in the exhaust system and thus the emission is controlled. Different kinds of problems are associated with noble metal based catalytic converter. A catalytic converter with a new catalyst for compression ignition engine is considered in this study. The catalytic converter is designed and developed with a new catalyst. Due to better durable characteristics and poison resistant nature, non-noble metal based material limestone (mullite) is selected as a catalyst for catalytic convertor and the emission characteristics are studied on four stroke single cylinder CI engine by using mullite based catalytic converter. The results are compared without catalytic converter in the same engine. In the design stage, the back pressure analysis is performed on perforated mullite plate with ANSYS software. After arriving satisfactory results, the design is taken for development. The…
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Study of NOx Reduction Efficiency in NSR and NSR-SCR Combined Systems

Vellore Institute of Technology-Saravanan Supramani, Ramesh Kumar Chidambaram
  • Technical Paper
  • 2019-28-0087
Published 2019-10-11 by SAE International in United States
The present study was carried out to analyze the catalytic action of K2O-Al2O3 in NOx Storage and Reduction (NSR) monolith catalyst and Fe2O3-TiO2 in Selective Catalytic Reduction (SCR) monolith catalyst. The core objective of this investigation is to determine the maximum percentage of Oxides of Nitrogen (NOx) reduction in NSR and NSR-SCR combined system with respect to engine exhaust gas temperature and compares the results with the results of the conventional mode of operation. To accomplish this task monolith ceramic bricks were coated with K2O-Al2O3 (NSR) and Fe2O3-TiO2 (SCR) catalyst and were placed in different configurations inside the catalytic chamber. Several trials were attempted to get the optimal operating temperature that has a maximum NOx removal efficiency when successively connecting a single NSR catalyst and the combined NSR-SCR double bed catalyst. Single NSR monolith at 320 °C, showed the best NOx conversion rate of 74%. The double NSR-SCR configuration permitted the SCR catalyst storing ammonia to respond with NOx leaving from the NSR. The SCR reaction between ammonia which leaves from NSR, later adsorbed by…
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A Novel 1D Co-Simulation Framework for the Prediction of Tailpipe Emissions under Different IC Engine Operating Conditions

Aristotle University of Thessaloniki-Grigorios Koltsakis, Zissis Samaras
EMPA-Panayotis Dimopoulos Eggenschwiler, Viola Papetti, Jakub Rojewski, Patrik Soltic
Published 2019-09-09 by SAE International in United States
The accurate prediction of pollutant emissions generated by IC engines is a key aspect to guarantee the respect of the emission regulation legislation. This paper describes the approach followed by the authors to achieve a strict numerical coupling of two different 1D modeling tools in a co-simulation environment, aiming at a reliable calculation of engine-out and tailpipe emissions. The main idea is to allow an accurate 1D simulation of the unsteady flows and wave motion inside the intake and exhaust systems, without resorting to an over-simplified geometrical discretization, and to rely on advanced thermodynamic combustion models and kinetic sub-models for the calculation of cylinder-out emissions. A specific fluid dynamic approach is then used to track the chemical composition along the exhaust duct-system, in order to evaluate the conversion efficiency of after-treatment devices, such as TWC, GPF, DPF, DOC, SCR and so on. This co-simulation environment is validated against a real engine configuration which was instrumented and tested at EMPA labs. A 4-cylinder SI, turbocharged, CNG engine is investigated at different loads and revolution speeds, to…
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Analysis and Modeling of NOx Reduction Based on the Reactivity of Cu Active Sites and Brønsted Acid Sites in a Cu-Chabazite SCR Catalyst

Waseda Univ-Yoshihisa Tsukamoto, Takao Fukuma, Jin Kusaka
Published 2019-09-09 by SAE International in United States
The NOx-reducing activity of a Cu-chabazite selective catalytic reduction (SCR) catalyst was analyzed over a wide temperature range. The analysis was based on the ammonia SCR (NH3-SCR) mechanism and accounted for Cu redox chemistry and reactions at Brønsted acid sites. The reduction of NOx to N2 (De-NOx) at Cu sites was found to proceed via different paths at low and high temperatures. Consequently, the rate-limiting step of the SCR reaction at Cu sites varied with the temperature. The rate of NOx reduction at Cu sites below 200°C was determined by the rate of Cu oxidation. Conversely, the rate of NOx reduction above 300°C was determined by the rate of NH3 adsorption on Cu sites. Moreover, the redox state of the active Cu sites differed at low and high temperatures. To clarify the role of the chabazite Brønsted acid sites, experiments were also performed using a H-chabazite catalyst that lacks Cu sites. NOx reduction via the NO2-NH3 reaction was found to occur at Brønsted acid sites at high temperatures (up to 600°C). We also analyzed the…
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Analysis of TWC Characteristics in a Euro6 Gasoline Light Duty Vehicle

Aristotle University Thessaloniki-Grigorios Koltsakis
Empa-Viola Papetti, Panayotis Dimopoulos Eggenschwiler
Published 2019-09-09 by SAE International in United States
A Euro6 gasoline light duty vehicle has been tested at the engine dynamometer and the emissions have been analyzed upstream and downstream the Three-Way-Catalyst (TWC) during a WLTC cycle. Catalyst simulations have been used for assessing the processes inside the catalytic converter using a reaction scheme based on 19 brutto reactions (direct oxidation and reduction, selective catalytic reductions with CO, C3H6 and H2, steam reforming, water-gas shift and bulk ceria as well as surface ceria reactions). The reactions have been parameterized in order to best approximate the measurements.Based on the reactions taken into account, the real vehicle emissions can be predicted with good accuracy. The simulations show that the cycle emissions comprise mainly the cold start contribution as well as discrete emission break-through events during transients. During cold start no reactions are evident in the catalyst before the temperature of the gas entering the catalyst reaches 270°C. Following the light-off, prevailing reactions are direct oxidation as well as surface ceria reactions for CO and THC. NO reduction during cold start is due to reaction with…
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Experimental and Numerical Analysis of Latest Generation Diesel Aftertreatment Systems

Cornaglia SpA-Alessio Tarabocchia
Politecnico di Torino-Francesco Sapio, Federico Millo, Debora Fino, Alessandro Monteverde, Enrico Sartoretti
Published 2019-09-09 by SAE International in United States
A comprehensive experimental and numerical analysis of two state-of-the-art diesel AfterTreatment Systems (ATS) for automotive applications is presented in this work.Both systems, designed to fulfill Euro 6 emissions regulations standards, consist of a closed-coupled Diesel Oxidation Catalyst (DOC) followed by a Selective Catalytic Reduction (SCR) catalyst coated on a Diesel Particulate Filter (DPF), also known as SCR on Filter (SCRoF or SCRF). While the two systems feature the same Urea Water Solution (UWS) injector, major differences could be observed in the UWS mixing device, which is placed upstream of the SCRoF, whose design represents a crucial challenge due to the severe flow uniformity and compact packaging requirements.First, both the ATS were experimentally characterized to determine the physical-chemical properties of the catalysts, the UWS spray characteristics (i.e. liquid penetration, droplets size) and to evaluate the NOx conversion efficiency under steady state flow conditions, representative of type-approval operating conditions. The experiments highlighted significant differences in terms of NOx conversion efficiency between the two ATS, especially at low temperature operation.In order to highlight the root causes of these…
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Multidimensional Modeling of SCR Systems via the Lattice Boltzmann Method

University of Rome Niccolò Cusano-Giovanni Di Ilio
University of Rome Tor Vergata-Vesselin Krastev, Gino Bella, Giacomo Falcucci
  • Technical Paper
  • 2019-24-0048
Published 2019-09-09 by SAE International in United States
In this paper, we deploy a novel, multidimensional approach to simulate SCR reactors across physical scales. For the first time, a full 3D Lattice Boltzmann (LB) solver is developed, able to accurately capture the fluid dynamic phenomena taking place inside SCR reactors, as well as the catalytic conversion of NOx. The influence of engine load on exhaust gas mass flow rate and catalytic converter activity is taken into account. The proposed approach is computationally light and the results prove the reliability and versatility of the LB Method for the simulation of the complex phenomena that take place inside the after-treatment devices.
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Chemical and Physical Characteristics of Organic Particulate Matter from Exhaust After-Treatment System of Euro 6 Diesel Engine Operating at Full Load

FPT Motorenforschung AG-Wolfgang Gstrein, Konstantinos Priftis
Istituto Motori-CNR-Ezio Mancaruso, Bianca Maria Vaglieco
  • Technical Paper
  • 2019-24-0053
Published 2019-09-09 by SAE International in United States
The current legislation does not take into account the limitation of sub 23 nm particles from engine. Nevertheless, the Common Rail Diesel engine emits a large number of nanoparticle, solid and volatiles, that are very dangerous for human health. In this contest, the challenge of the “dieper EU project” is to apply advanced technologies for exhaust after-treatment to existing diesel engines and to optimize the characteristics of a new generation of engines with regards to emissions, fuel consumption and drivability.Aim of the present paper is to provide useful information for the development of the after-treatment system that will have to fulfill Euro6 further steps. In order to characterize the chemical and physical nature of Particulate Matter emitted from Euro 6b Medium Duty diesel engine, the pollutants were collected and analyzed: from engine-out, downstream of the particulate filter (DPF), and at the exit of a selective catalytic reactor (SCR). An array of chemical, physical and spectroscopic techniques (Gas chromatography coupled with mass spectrometry (GC-MS), mobility analyzer, UV-visible absorption and fluorescence spectroscopy) was applied for characterizing the…
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Optimization of the Exhaust Aftertreatment System of a Heavy Duty Diesel Engine by Means of Variable Valve Timing

Technische Universität Braunschweig-Marius Betz, Peter Eilts
Published 2019-09-09 by SAE International in United States
In view of the current political debate, it can be assumed that the nitrogen oxide limits for commercial vehicles will be further reduced. This is also demonstrated by the currently voluntary certification of the CARB Optional Low NOX legislation, which requires nitrogen oxide emissions of 0.027 g/kWh. This corresponds to a reduction of 93 % compared to the current EU VI standard. Therefore, the optimization of EAT systems represents an essential research focus for future commercial vehicle applications.One way to optimize the EAT system may be the usage of variable valve actuation. Existing investigations show an exhaust gas temperature increase with intake valve timing adjustment, also known as Miller timing. But the authors conclude that it cannot accelerate the warm up process. With regard to the effects on the exhaust aftertreatment system and the resulting tailpipe emissions, only improved HC and CO oxidation could be identified so far. In addition, a potential for improved NOX reduction is expected in the exhaust gas temperature increase.Therefore, further investigations have been carried out. The investigations presented in this…
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