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Catalytic NOx Control Technologies for Diesel and GDI Engines

2019-04-01
Lean burn engines (diesel and GDI) boast higher fuel economy and cleaner emissions than conventionally tuned engines while producing equivalent power. They employ higher combustion chamber compression ratios, significant air intake swirl and precise lean-metered direct fuel injection. The downfall of lean-burn technology, however, is increased exhaust NOx emissions (due to higher heat and cylinder pressure) and a somewhat narrower RPM power-band (due to slower burn rates of lean mixtures). Removal of NOx from exhausts is a critical need for emission standards and ambient ozone requirements.
Standard

Instrumentation and Techniques for Exhaust Gas Emissions Measurement

2011-06-10
CURRENT
J254_201106
This SAE Recommended Practice establishes uniform laboratory techniques for the continuous and bag-sample measurement of various constituents in the exhaust gas of the gasoline engines installed in passenger cars and light-duty trucks. The report concentrates on the measurement of the following components in exhaust gas: hydrocarbons (HC), carbon monoxide (CO), carbon dioxide (CO2), oxygen (O2), and nitrogen oxides (NOx). NOx is the sum of nitric oxide (NO) and nitrogen dioxide (NO2). A complete procedure for testing vehicles may be found in SAE J1094. This document includes the following sections: 1. Scope 2. References 3. Emissions Sampling Systems 4. Emissions Analyzers 5. Data Analysis 6. Associated Test Equipment 7. Test Procedures
Book

Emissions and Air Quality

1999-06-09
This book evaluates the current worldwide state of knowledge about the interrelationship between emissions and air quality. This study describes the contribution of passenger car and commercial vehicle traffic to local and global emission situations, and the consequences for the environment.
Standard

Measurement of Intake Air or Exhaust Gas Flow of Diesel Engines

2011-06-13
CURRENT
J244_201106
This procedure establishes recommendations on the measurement of diesel engine intake air flow under steady-state test conditions. The measurement methods discussed have been limited to metering systems and associated equipment found in common usage in the industry, specifically, nozzles, laminar flow devices, and vortex shedding. The procedure establishes accuracy goals as well as explains proper usage of equipment. The recommendations concerning diesel engine exhaust mass flow measurements are minimal in scope.
Magazine

SAE Off-Highway Engineering 2008-03-01

2008-03-01
In search of the perfect burn The simultaneous download pressures on NOx and PM continue to make research into higher injection pressures and alternative combustion solutions such as homogenous-charge compression ignition attractive. One way to stop a train A new self-energizing electrohydraulic brake offers the advantages of hydraulic brake actuation without the disadvantages of a centralized hydraulic power supply. A model combustion: from art to science Analysis tools, advanced hardware provide insight into combustion process, refining the cylinder's 'big bang.' The datalinked vehicle In the fields and on the job site with GPS.
Collection

Advances in NOx Reduction Technology, 2014

2014-04-01
This technical paper collection covers topics such as: new materials for lean NOx traps (LNT) and Selective Catalytic Reduction (SCR); system integration and durability; advances in NOx catalyst substrates, novel reductants and mixing designs.
Collection

Advances in NOx Reduction Technology, 2015

2015-04-14
This technical paper collection will focus on ‘Advances in NOx Reduction Technology’. The topics covered will include: new materials for lean NOx traps (LNT) and Selective Catalytic Reduction (SCR); system integration and durability; advances in NOx catalyst substrates, novel reductants and mixing designs.
Video

Monitoring NO2 Production of a Diesel Oxidation Catalyst

2012-01-24
A combination of laboratory reactor measurements and vehicle FTP testing has been combined to demonstrate a method for diagnosing the formation of NO2 from a diesel oxidation catalyst (DOC). Using small cores from a production DOC and simulated diesel exhaust, the laboratory reactor experiments are used to support a model for DOC chemical reaction kinetics. The model we propose shows that the ability to produce NO2 is chemically linked to the ability of the catalyst to oxidize hydrocarbon (HC). For thermally damaged DOCs, loss of the HC oxidation function is simultaneous with loss of the NO2 production function. Since HC oxidation is the source of heat generated in the DOC under regeneration conditions, we conclude that a diagnostic of the DOC exotherm is able to detect the failure of the DOC to produce NO2. Vehicle emissions data from a 6.6 L Duramax HD pick-up with DOC of various levels of thermal degradation is provided to support the diagnostic concept.
Video

New Particulate Matter Sensor for On Board Diagnosis

2012-02-16
The presentation describes technology developments and the integration of these technologies into new emission control systems. As in other years, the reader will find a wide range of topics from various parts of the world. This is reflective of the worldwide scope and effort to reduce diesel exhaust emissions. Topics include the integration of various diesel particulate matter (PM) and Nitrogen Oxide (NOx) technologies as well as sensors and other emissions related developments. Presenter Atsuo Kondo, NGK Insulators, Ltd.
Video

SCR Deactivation Study for OBD Applications

2012-06-18
Selective catalytic reduction (SCR) catalysts will be used to reduce oxides of nitrogen (NOx) emissions from internal combustion engines in a number of applications [1,2,3,4]. Southwest Research Institute® (SwRI)® performed an Internal Research & Development project to study SCR catalyst thermal deactivation. The study included a V/W/TiO2 formulation, a Cu-zeolite formulation and an Fe-zeolite formulation. This work describes NOx timed response to ammonia (NH3) transients as a function of thermal aging time and temperature. It has been proposed that the response time of NOx emissions to NH3 transients, effected by changes in diesel emissions fluid (DEF) injection rate, could be used as an on-board diagnostic (OBD) metric. The objective of this study was to evaluate the feasibility and practicality of this OBD approach.
Video

Brief Investigation of SCR High Temperature N2O Production

2012-06-18
Nitrous Oxide (N2O) is a greenhouse gas with a Global Warming Potential (GWP) of 298-310 [1,2] (298-310 times more potent than carbon dioxide (CO2)). As a result, any aftertreatment system that generates N2O must be well understood to be used effectively. Under low temperature conditions, N2O can be produced by Selective Catalytic Reduction (SCR) catalysts. The chemistry is reasonably well understood with N2O formed by the thermal decomposition of ammonium nitrate [3]. Ammonium nitrate and N2O form in oxides of nitrogen (NOx) gas mixtures that are high in nitrogen dioxide (NO2)[4]. This mechanism occurs at a relatively low temperature of about 200°C, and can be controlled by maintaining the nitric oxide (NO)/NO2 ratio above 1. However, N2O has also been observed at relatively high temperatures, in the region of 500°C.
Video

Development of a 3rd Generation SCR NH3-Direct Dosing System for Highly Efficient DeNOx

2012-06-18
In this project funded by the Bayerische Forschungsstiftung two fundamental investigations had been carried out: first a new N-rich liquid ammonia precursor solution based on guanidine salts had been completely characterized and secondly a new type of side-flow reactor for the controlled catalytic decomposition of aqueous NH3 precursor to ammonia gas has been designed, applied and tested in a 3 liter passenger car diesel engine. Guanidine salts came into the focus due to the fact of a high nitrogen-content derivate of urea (figure 1). Specially guanidinium formate has shown extraordinary solubility in water (more than 6 kg per 1 liter water at room temperature) and therefore a possible high ammonia potential per liter solution compared to the classical 32.5% aqueous urea solution (AUS32) standardized in ISO 22241 and known as DEF (diesel emission fluid), ARLA32 or AdBlue®. Additionally a guanidine based formulation could be realized with high freezing stability down to almost ?30 °C (?
Video

Development of DPF/SCR System for Heavy Duty Diesel Engine

2012-06-15
The development of PM and NOx reduction system with the combination of DOC included DPF and SCR catalyst in addition to the AOC sub-assembly for NH3 slip protection is described. DPF regeneration strategy and manual regeneration functionality are introduced with using ITH, HCI device on the EUI based EGR, VGT 12.3L diesel engine at the CVS full dilution tunnel test bench. With this system, PM and NOx emission regulation for JPNL was satisfied and DPF regeneration process under steady state condition and transient condition (JE05 mode) were successfully fulfilled. Manual regeneration process was also confirmed and HCI control strategy was validated against the heat loss during transient regeneration mode. Presenter Seung-il Moon
Video

Characterization of a New Advanced Diesel Oxidation Catalyst with Low Temperature NOx Storage Capability for LD Diesel

2012-06-18
Currently, two consolidated aftertreatment technologies are available for the reduction of NOx emissions from diesel engines: Urea SCR (Selective Catalytic Reduction) systems and LNT (Lean NOx Trap) systems. Urea SCR technology, which has been widely used for many years at stationary sources, is becoming nowadays an attractive alternative also for light-duty diesel applications. However, SCR systems are much more effective in NOx reduction efficiency at high load operating conditions than light load condition, characterized by lower exhaust gas temperatures.
Video

On-Road Evaluation of an Integrated SCR and Continuously Regenerating Trap Exhaust System

2012-06-18
Four-way, integrated, diesel emission control systems that combine selective catalytic reduction for NOx control with a continuously regenerating trap to remove diesel particulate matter were evaluated under real-world, on-road conditions. Tests were conducted using a semi-tractor with an emissions year 2000, 6-cylinder, 12 L, Volvo engine rated at 287 kW at 1800 rpm and 1964 N-m. The emission control system was certified for retrofit application on-highway trucks, model years 1994 through 2002, with 4-stroke, 186-373 kW (250-500 hp) heavy-duty diesel engines without exhaust gas recirculation. The evaluations were unique because the mobile laboratory platform enabled evaluation under real-world exhaust plume dilution conditions as opposed to laboratory dilution conditions. Real-time plume measurements for NOx, particle number concentration and size distribution were made and emission control performance was evaluated on-road.
Video

An Experimental Analysis on Diesel/n-Butanol Blends Operating in Partial Premixed Combustion in a Light Duty Diesel Engine

2012-06-18
This paper reports results of an experimental investigation performed on a commercial diesel engine supplied with fuel blends having low cetane number to attain a simultaneous reduction in NOx and smoke emissions. Blends of 20% and 40% of n-butanol in conventional diesel fuel have been tested, comparing engine performance and emissions to diesel ones. Taking advantage of the fuel blend higher resistance to auto ignition, it was possible to extend the range in which a premixed combustion is achieved. This allowed to match the goal of a significant reduction in emissions without important penalties in fuel consumption. The experimental activity was carried on a turbocharged, water cooled, 4 cylinder common rail DI diesel engine. The engine equipment included an exhaust gas recirculation system controlled by an external driver, a piezo-quartz pressure transducer to detect the in-cylinder pressure signal and a current probe to acquire the energizing current to the injector.
Video

Evaluation of a NOx Transient Response Method for OBD of SCR Catalysts

2012-01-30
OBD requirements for aftertreatment system components require monitoring of the individual system components. One such component can be an NH3-SCR catalyst for NOx reduction. An OBD method that has been suggested is to generate positive or negative spikes in the inlet NH3 concentration, and monitor the outlet NOx transient response. A slow response indicates that the catalyst is maintaining its NH3 storage capacity, and therefore it is probably not degraded. A fast response indicates the catalyst has lost NH3 storage capacity, and may be degraded. The purpose of the work performed at Southwest Research Institute was to assess this approach for feasibility, effectiveness and practicality. The presentation will describe the work performed, results obtained, and implications for applying this method in test laboratory and real-world situations. Presenter Gordon J. Bartley, Southwest Research Institute
Video

SAE Eye on Engineering: Bosch's New Diesel Tech

2018-05-17
Diesel engines got an undeserved bad rap when Volkswagen was caught cheating on its emissions certification. In this episode of SAE Eye on Engineering, Editor-in-Chief Lindsay Brooke looks at Bosch's technology solution to reduce NOx emissions. SAE Eye on Engineering also airs Monday mornings on WJR 760 AM Detroit's Paul W. Smith Show.
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