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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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Gasoline Particulate Filter Substrate Heterogeneity Effects on Its Performance

Combustion & Reaction Characterization Laboratory, USA Texas A&M Department of Mechanical Engineering, USA-Pengze Yang
Texas A&M Department of Mechanical Engineering, USA-Michael B. Pate
  • Journal Article
  • 03-13-01-0004
Published 2019-10-14 by SAE International in United States
Continuously tightening Particulate Matter (PM) and Particulate Number (PN) regulations make Gasoline Particulate Filters (GPFs) with high filtration efficiency and low pressure drop highly desirable as Gasoline Direct Injection (GDI) engines increase in market share. Due to packaging constraints, GPFs are often coated with three-way catalyst (TWC) materials to achieve four-way functionality. Therefore, it is critical to investigate the effects of various washcoating strategies on GPF performance. A three-dimensional (3D) Computational Fluid Dynamics (CFD) model, along with an analytical filtration model was created. A User Defined Function (UDF) was implemented to define the heterogeneous properties of the GPF wall due to washcoating or ash membrane application. The model demonstrated the ability to predict transient filtration efficiency and pressure drop of uncoated and washcoated GPFs. Simulation results showed the evenly coated GPF yielded the best performance compared to other washcoating profiles. The model-predicted results indicated that the sample GPF with a 2.6 g/L ash loading was able to achieve a balance between high initial filtration efficiency and low pressure drop.
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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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Development of Three Way Catalyst Aging Model: Application to Real Driving Emission Condition

Toyota Motor Europe NV/SA-Julie Le Louvetel-Poilly, Shankar Balaji, Francois Lafossas
  • Technical Paper
  • 2019-24-0047
Published 2019-09-09 by SAE International in United States
Further reduction of vehicles pollutant and CO2 emissions is required to prevent global warming and to improve air quality. The exhaust system is designed to ensure low emission during all life of the vehicle. As catalyst aging is affecting the catalyst performance, such impact needs to be consider upfront during the design of the fresh catalyst. Until now, the exhaust system design are evaluated based on real tests for each vehicle, using exhaust lines aged on engine test benches or burner benches. This induces major investigation limitations such as: late evaluation in development cycle, high testing and prototyping cost. The usage of Model Based Development approach can be a powerful way to improve this process by allowing system evaluation under several aging conditions at early development stage. The present study focuses on modelling of the Three Way Catalyst (TWC) aging to predict the mileage impact on tailpipe emissions. The activity was divided in 4 steps: 1- Development of a detailed TWC for 4 different aging levels. The impact of aging is considered by tuning the…
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Analysis of the Emission Conversion Performance of Gasoline Particulate Filters Over Lifetime

Corning GmbH-Dominik Rose, Thorsten Boger
FEV Europe GmbH-Christof Schernus, Michael Görgen, Jim Cox, Martin Nijs, Johannes Scharf
Published 2019-09-09 by SAE International in United States
Gasoline particulate filters (GPF) recently entered the market, and are already regarded a state-of-the-art solution for gasoline exhaust aftertreatment systems to enable EU6d-TEMP fulfilment and beyond. Especially for coated GPF applications, the prognosis of the emission conversion performance over lifetime poses an ambitious challenge, which significantly influences future catalyst diagnosis calibrations. The paper presents key-findings for the different GPF application variants. In the first part, experimental GPF ash loading results are presented. Ash accumulates as thin wall layers and short plugs, but does not penetrate into the wall. However, it suppresses deep bed filtration of soot, initially decreasing the soot-loaded backpressure. For the emission calibration, the non-linear backpressure development complicates the soot load monitoring, eventually leading to compromises between high safety against soot overloading and a low number of active regenerations. In the second part, a relevant share of ash deposits inside three-way catalysts (TWC) is depicted. In an experiment, the oxygen storage capacity (OSC) of a three-way catalyst was significantly lowered by ash, while a coated GPF showed little effects. A subsequent OSC regeneration…
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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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One-Dimensional Modeling of a Thermochemical Recuperation Scheme for Improving Spark-Ignition Range Extender Engine Efficiency

Univ of Minnesota-Twin Cities-William F. Northrop, Darrick Zarling
  • Technical Paper
  • 2019-24-0066
Published 2019-09-09 by SAE International in United States
Range extender (REx) engines have promise for providing low-cost energy for future battery electric vehicles. Due to their restricted operation range, REx engines provide an opportunity to implement system-level schemes that are less attractive for engines designed for highly transient operation. This paper explores a thermochemical recuperation (TCR) scheme for a 2-cylinder BMW spark-ignition REx engine using a 1-D model implemented in GT-Power™. The TCR reactor employs a unique catalytic heat exchange configuration that enables efficient transfer of exhaust sensible and chemical enthalpy to steam reform the incoming fuel. The engine model without the TCR reactor was validated using experimental emissions and performance data from a BMW engine operating on a test stand. A custom integrated heat exchanger and catalyst model was created and integrated with the validated engine. A parametric modeling sweep was conducted with iso-octane as fuel over a range of reformed fuel fraction. With the TCR reactor operating at a molar steam to carbon ratio of 1.0, engine efficiency was increased by 2.9% over the baseline REx engine within the most efficient…
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Development of a Dedicated CNG Three-Way Catalyst Model in 1-D Simulation Platforms

FPT Industrial SpA-Stefano Golini, Francesco Giovanni Rutigliano
Istituto Motori CNR-Carlo Beatrice, Valentina Fraioli
Published 2019-09-09 by SAE International in United States
A growing interest towards heavy-duty engines powered with NG, dictated by stringent regulations in terms of emissions, has made it essential to study a specific Three-Way Catalyst (TWC). Oxygen storage phenomena characterize the catalytic converter efficiency under real world driving operating conditions and, consequently, during strong dynamics in Air-to-Fuel ratio (AFR).A numerical “quasi-steady” model has been set-up to simulate the chemical process inside the reactor. A dedicated experimental campaign has been performed in order to evaluate the catalyst response to a defined λ variation, thus providing the data necessary for the numerical model validation. In fact, goal of the present research activity was to investigate the effect of very fast composition transitions of the engine exhaust typical of the mentioned driving conditions (including fuel cutoffs etc.) on the catalyst performance and on related emissions.A surface reactions kinetic mechanism, representing CH4, CO, H2 oxidation and NO reduction, has been appropriately calibrated in steady-state operation, using a step-by-step procedure all over the engine operating conditions at different AFRs. Then transient conditions were numerically reproduced, through cyclical and…
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Exhaust Purification Performance Enhancement by Early Activation of Three Way Catalysts for Gasoline Engines Used in Hybrid Electric Vehicles

NE Chemcat Corporation-Makoto Nagata
Waseda Univesity-Toshinori Okajima, Ryota Sone, Xieyang Yan, Ryoya Inoue, Suchitra Sivakumar, Hajime Shingyouchi, Jin Kusaka, Kyohei Yamaguchi
Published 2019-09-09 by SAE International in United States
Three-way catalyst (TWC) converters are used to remove harmful substances (e.g., carbon monoxide (CO), nitrogen oxides (NOx), and hydrocarbons (HC)) emitted from gasoline engines. However, a large amount of emissions could be emitted before the TWC reaches its light-off temperature during a cold start. For hybrid electric vehicles (HEVs) powered by gasoline engines, the emission purification performance by TWC converters unfortunately deteriorates because of mode switching from engine to battery and vice versa, which can repeatedly generate cold start conditions for the TWCs. In this study, aiming to reduce emissions from series HEVs by early activation of TWCs, numerical simulations and experiments are carried out. An HEV is tested on a chassis dynamometer in the Worldwide Light-duty Test Cycle (WLTC) mode. The upstream and downstream gas conditions of the close-coupled catalyst converter are measured. A test piece is taken from the same catalyst and used in model gas experiments to decide the chemical reaction scheme and each corresponding reaction rate parameter. A 1-D numerical simulation TWC model, which includes 13 chemical species with 22 global…
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Event-Driven Simulation of Particle-Particle and Particle-Surface Collisions in Ice Crystal Icing

ICI Physics-Thomas Charles Currie
Published 2019-06-10 by SAE International in United States
This paper describes an event-driven simulation tool for predicting particle-particle and particle-surface interactions in ice crystal icing (ICI). A new accretion model which is much less empirical than existing models for predicting ICI accretion is also described. Unlike previous models, the new “gouge/bounce model” (GBM) differentiates between (erosion) losses resulting from particle bounce and those resulting from particle gouging. A bounce threshold based on the tangential Stokes number is used to calculate most of the bounce loss. The GBM also predicts ejecta velocities and directions, at least approximately, which is important because most of the mixed-phase mass flux impacting a surface actually bounces off or erodes existing material in ICI, thereby increasing the mass flux downstream. The event-driven simulation tool, denoted COLLIDE, has been applied to two test cases in which accretion growth appeared to be affected by TWC in a manner beyond that which would be expected from the accumulation parameters. An existing correlation-based accretion model (CBM), modified to predict erosion dependence on particle diameter, is also implemented and applied to the test cases.…
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