Browse Topic: Lean NOx traps

Items (93)

Studying the Lean Burn Operation in Two-Wheelers to Increase Fuel Efficiency and Investigate the Use of Lean NOx Trap Catalyst (LNT) for Lean Burn System

2024-32-005804/18/2025

This study offers an overview of the impact of lean burn technology in two-wheeler vehicles, specifically concentrating on enhancing the fuel economy and addressing the challenges associated with its adoption. Lean burn systems, characterized by a fuel-air mixture with a higher air content than stoichiometric ratio. The study focuses on technology which meets stringent emission standards while enabling the optimization of fuel efficiency. The lean burn system employs strategies to optimize air-fuel ratio using electronic fuel injection, ignition timing control, and advanced engine control algorithms like - updated torque modulation control algorithm for drivability, lambda control algorithm for rich and lean switch and NOx modelling algorithm for LNT catalyst efficiency tracking. The challenges related to lean burn systems, includes issues related to combustion stability, nitrogen oxide (NOx) emissions, and their impact on drivability, is summarized in the study. Mitigation strategies

Somasundaram, Karthikeyan, Sivaji, Purushothaman, John Derin, C, Vishal, Karwa, Manoj Kumar, S, Maynal, Rajesh

Calibration and Parametric Investigations on Lean NOx Trap and Particulate Filter Models for a Light Duty Diesel Engine

2020-01-065704/14/2020

To comply with the stringent future emission mandates of light-duty diesel engines, it is essential to deploy a suitable combination of emission control devices like diesel oxidation catalyst (DOC), diesel particulate filter (DPF) and DeNOx converter (LNT or SCR). Arriving at optimum size and layout of these emission control devices for a particular engine through experiments is both time and cost-intensive. Thus, it becomes important to develop suitable well-tuned simulation models that can be helpful to optimize individual emission control devices as well as arrive at an optimal layout for achieving higher conversion efficiency at a minimal cost. Towards this objective, the present work intends to develop a one-dimensional Exhaust After Treatment Devices (EATD) model using a commercial code. The model parameters are fine-tuned based on experimental data. The EATD model is then validated with experiment data that are not used for tuning the model. Subsequently, the model was used for

Bagavathy, S. Suresh, Ramesh, A, Krishnasamy, Anand, Pandian, Senthur

Diesel Vehicle with Ultra-Low NOx Emissions on the Road

2019-24-014509/09/2019

The gap between diesel vehicle emissions in laboratory tests compared to those in use has been addressed by the introduction of the Real Driving Emissions (RDE) requirements. Modern diesel technology now demonstrates low emissions on the road over a wide range of driving conditions. This paper further demonstrates that consistent low nitrogen oxide (NOx) and particle number (PN) emissions can be achieved over a wide range of driving conditions beyond Euro 6d RDE requirements, with emission control technologies combined in an integrated approach. An LNT (Lean NOx Trap) is combined with a dual-dosing SCR (Selective Catalytic Reduction) system. Low-load NOx control is achieved by the LNT in combination with a close-coupled SCR coated on the Diesel Particulate Filter (SDPF). High load conditions, on the other hand, are covered by the underfloor SCR system with a second AdBlue® injector. A P0 48V mild-hybrid system is also available to support the NOx control and to ensure good driving

Demuynck, Joachim, Favre, Cecile, Bosteels, Dirk, Bunar, Frank, Spitta, Joachim, Kuhrt, Andreas

Engine-Aftertreatment in Closed-Loop Modeling for Heavy Duty Truck Emissions Control

2019-01-098604/02/2019

An engine-aftertreatment computational model was developed to support in-loop performance simulations of tailpipe emissions and fuel consumption associated with a range of heavy-duty (HD) truck drive cycles. For purposes of this study, the engine-out exhaust dynamics were simulated with a combination of steady-state engine maps and dynamic correction factors that accounted for recent engine operating history. The engine correction factors were approximated as dynamic first-order lags associated with the thermal inertia of the major engine components and the rate at which engine-out exhaust temperature and composition vary as combustion heat is absorbed or lost to the surroundings. The aftertreatment model included catalytic monolith components for diesel exhaust oxidation, particulate filtration, and selective catalytic reduction of nitrogen oxides (NOx) with urea. Both the engine and aftertreatment models have been calibrated with dynamometer measurements from a commercial 2010

Gao, Zhiming, Deter, Dean, Smith, David, Pihl, Josh, Daw, C. Stuart, Parks, James

Model-Based Approaches in Developing an Advanced Aftertreatment System: An Overview

2019-01-002601/15/2019

Cummins has recently launched next-generation aftertreatment technology, the Single ModuleTM aftertreatment system, for medium-duty and heavy-duty engines used in on-highway and off-highway applications. Besides meeting EPA 2010+ and Euro VI regulations, the Single ModuleTM aftertreatment system offers 60% volume and 40% weight reductions compared to current aftertreatment systems. In this work, we present model-based approaches that were systematically adopted in the design and development of the Cummins Single ModuleTM aftertreatment system. Particularly, a variety of analytical and experimental component-level and system-level validation tools have been used to optimize DOC, DPF, SCR/ASC, as well as the DEF decomposition device. The highlights of this work can be summarized as follows: a). internal dosing is more efficient than external dosing to control HC slip; High CPSI DOCs show better HC oxidation performance at high SV due to enhanced mass transfer; b). the adopted advanced

Su, Changsheng, Brault, Joseph, Munnannur, Achuth, Liu, Z. Gerald, Milloy, Sean, Harinath, Arvind, Dunnuck, David, Federle, Ken

Experimental Analysis of LNT/DPF after Treatment System on a Passenger Car for Indian Road Condition

2019-26-015501/09/2019

The Lean NOx Trap (LNT) / Diesel Particulate Filter (DPF) system has been developed as one of key technologies to comply with BS VI regulations. For DPF system it is necessary to prevent excessive soot accumulation and high temperature which can lead to eventual DPF failure. For LNT system it is necessary to maintain the NOx conversion efficiency to meet the required BS VI norms. Considering the Indian road condition a methodology was developed to evaluate the soot, de-NOx and de-SOx regeneration for development of optimized LNT/DPF system. The study was carried on >1500cc, LNT/DPF equipped Euro VI diesel passenger car to evaluate the effect of regeneration characteristics in real Indian driving condition. The study was carried on different conditions such as traffic [urban mode and rural mode] and ambient condition like temperature and weather on the regeneration behavior of LNT/DPF. A concurrent study was conducted on the regeneration frequency, timing, temperature, success rate on

Tiwari, Rahul Kumar, Balagangatharan, Balamuralitharan

Catalyst-Based BS VI Stage 2 Emission Control Solutions for Light Duty Diesel

2019-26-014101/09/2019

Various types of after-treatment system for BS VI Stage 1 are being assessed for the Light Duty Diesel (LDD) segment. For BS VI Stage 2, Real Driving Emission (RDE) assessment will be newly introduced, which will require more robustness in emission control system capability. Although the detailed requirements for India BS VI stage 2 are still being discussed, a reasonable assumption is that similar systems to those being developed for Euro 6d, will work for India BS VI. This paper describes typical system designs for Euro 6d and also reveals newly developed SCRF® (Selective Catalytic Reduction Filter) based systems, which demonstrate excellent RDE emissions. In addition, newly developed Lean NOx Trap (NSC) coatings, which focus on low temperature NOx control used with SCRF® (NSC + SCRF®) also show excellent emission control capability as demonstrated in this case on the ARTEMIS Cycle. These systems have potential as promising LDD solutions for India BS VI stage 2.

Sumiya, Satoshi, Kumar, Abhishek, Wylie, James, Bergeal, David

Supervisory Controller for a Light Duty Diesel Engine with an LNT-SCR After-Treatment System

2018-01-176709/10/2018

Look ahead information can be used to improve the powertrain’s fuel consumption while efficiently controlling exhaust emissions. A passenger car propelled by a Euro 6d capable diesel engine is studied. In the conventional approach, the diesel powertrain subsystem control is rule based. It uses no information of future load requests but is operated with the objective of low engine out exhaust emission species until the Exhaust After-Treatment System (EATS) light off has occurred, even if fuel economy is compromised greatly. Upon EATS light off, the engine is operated more fuel efficiently since the EATS system is able to treat emissions effectively. This paper presents a supervisory control structure with the intended purpose to operate the complete powertrain using a minimum of fuel while improving the robustness of exhaust emissions. A supervisory controller assisted by look ahead information, and using a supervisory control interface that works in concert with low level local

Velmurugan, Dhinesh, McKelvey, Tomas, Lundberg, Daniel

Robust DPF Regeneration Control for Cost-Effective Small Commercial Vehicles

2017-24-012309/04/2017

Small commercial vehicles (SCV) with Diesel engines require efficient exhaust aftertreatment systems to reduce the emissions while keeping the fuel consumption and total operating cost as low as possible. To meet current emission legislations in all cases, a DOC and DPF and some NOx treatment device (e,g. lean NOx trap or SCR) are required. Creating a cost-effective SCV also requires keeping the cost for the exhaust aftertreatment system as low as possible because the contribution to total vehicle cost is high. By using more sophisticated and more robust operating strategies and control algorithms, the hardware cost can be reduced. To keep the calibration effort at a low level, it is necessary to apply only algorithms which have a time-efficient calibration procedure. This paper will focus on the active regeneration of the DPF. For safe and efficient DPF regeneration, a very reliable and stable DOC out temperature control is required. DOC characteristics and design are often limited by

Eck, Christopher, Nakano, Futoshi

Technology Challenges and Strategies for BS-VI in Commercial Vehicles

2017-28-193707/10/2017

Air Pollution is a major concern in our country due to which Indian Government has taken a decision to move from BS-IV to BS-VI which is nearly 90% reduction in NOx and 50% in particulate matter along with addition of particulate number regulation for BS-VI in comparison to BS-IV norms in very short span of time. Vehicle manufacturers are also having the challenge to produce low cost and fuel efficient product with BS-VI solution in order to meet tightening emission regulations and increasing needs of lower fuel consumption. Detailed study is done with different approaches to meet BS-VI emission which is elaborately explained in different aspect of engine design and after treatment parameter with its pros and cons. After Treatment selection plays an important role in engine development to meet stringent emission legislations and customer demands. Strategies for BS-VI were described with the advantage and drawbacks for after treatment selection. The cost of after treatment and its

Barman, Jyotirmoy, Arora, Prateek, Patchappalam, Kumar

NO ₂ /NOx Ratio and NH ₃ Storage Estimation of Automotive SCR Multi-Brick Systems

2017-01-097203/28/2017

Many control approaches for selective catalytic reduction (SCR) systems require knowledge of ammonia storage (NH3 storage) to dose urea accurately. Currently there are no technologies to directly measure internal NH3 storage in a vehicle, so it can only be inferred from hardware sensors located upstream, downstream, or in the catalyst. This paper describes an application of extended Kalman filter (EKF) state estimator used as a virtual sensor for urea injection control of a multi-brick aftertreatment system. The proposed estimator combines mean-value physics-based models of combined SCR and diesel particulate filter (SCR/DPF), SCR and clean-up catalyst (CUC). It uses hardware sensors at the inlet and outlet of the aftertreatment system, and includes no sensors between the catalysts. Performance of the proposed estimator was validated in simulations against a high-fidelity model of the aftertreatment system. The algorithm provides accurate estimates of the dominant gaseous species NOx

Figura, Jiri, Pekar, Jaroslav, Krejza, Pavel, Mracek, David, von Wissel, Dirk, Zhang, Tianran

Development of Advanced Ultra-Low PGM DOC for BS VI DOC+CDPF+SCR System

2017-26-014201/10/2017

Stricter regulatory standards are continuously adopted worldwide to control heavy duty emissions, and at the same time, fuel economy requirements have significantly lowered exhaust temperatures. The net result is a significant increase in Precious Group Metal (PGM) usage with current Diesel Oxidation Catalyst (DOC) technology. Therefore, the design and development of advanced DOC with ultra-low PGM to achieve highly beneficial emission performance improvement is necessary. The advanced DOC is synergized PGM (SPGM) with Mixed Metal Oxide (MMO). The presence of MMO in SPGM is responsible for NO oxidation to NO2 which is critical for the passive regeneration of the downstream filter and SCR function. This paper outlines the development of MMO for application in modern DOCs and addresses some specific challenges underlying this application. Lab and flow reactor data demonstrates MMO by itself owns great oxidation properties with high surface area available for NO oxidation reaction. In

Nazarpoor, Zahra, Golden, Steve, Liu, Ru-Fen

Development of Advanced Ultra-Low PGM DOC for BS VI DOC+CDPF+SCR System

2017-26-0142-TEST-REC01/10/2017

Nazarpoor, Zahra, Golden, Steve, Liu, Ru-Fen

Development of Ultra-Low Synergized PGM as Diesel Oxidation Catalyst for Heavy-Duty Applications

2016-01-232110/17/2016

Stricter regulatory standards are continuously adopted worldwide to control heavy duty emissions, and at the same time, fuel economy requirements have significantly lowered exhaust temperatures. The net result is a significant increase in Precious Group Metal (PGM) usage with current Diesel Oxidation Catalyst (DOC) technology. Therefore, the design and development of synergized precious metal (SPGM) in which ultra-low PGM is synergized with mixed metal oxide (MMO) to achieve highly beneficial emission performance improvement, is necessary. The presence of MMO in SPGM is responsible for NO oxidation to NO2 which is critical for the passive regeneration of the downstream filter and SCR function. This paper presents an initial study outlining the development of MMOs for application in modern DOCs and addresses some specific challenges underlying this application. Lab and flow reactor data in this study demonstrated SPGM DOCs thermal resistance and sulfur poisoning resistance. In addition

Nazarpoor, Zahra, Golden, Steve, Launois, Maxime, Kitazumi, Sen, Xie, Dianyong, McConnell, Campbell

Analysis of a Diesel Passenger Car Behavior On-Road and over Certification Duty Cycles

2016-01-232810/17/2016

Precise, repeatable and representative testing is a key tool for developing and demonstrating automotive fuel and lubricant products. This paper reports on the first findings of a project that aims to determine the requirements for highly repeatable test methods to measure very small differences in fuel economy and powertrain performance. This will be underpinned by identifying and quantifying the variations inherent to this specific test vehicle, both on-road and on Chassis Dynamometer (CD), that create a barrier to improved testing methods. In this initial work, a comparison was made between on-road driving, the New European Drive Cycle (NEDC) and World harmonized Light-duty Test Cycle (WLTC) cycles to understand the behavior of various vehicle systems along with the discrepancies that can arise owing to the particular conditions of the standard test cycles. The engine controller of a 2.0L diesel vehicle with active de-NOx and a particulate filter (DPF) has been monitored over

Chappell, Edward, Burke, Richard, Lu, Pin, Gee, Michael, Williams, Rod

Analysis of a Diesel Passenger Car Behavior On-Road and over Certification Duty Cycles

2016-01-2328-TEST-REC10/17/2016

Chappell, Edward, Burke, Richard, Lu, Pin, Gee, Michael, Williams, Rod

Virtual Test of Manufacturing Process Effect on Injector Design

2015-01-279409/29/2015

Diesel exhaust after treatment solutions using injection, such as urea-based SCR and lean NOx trap systems, effectively reduce the emission NOx level in various light vehicles, commercial vehicles, and industrial applications. The performance of the injector is crucial for successfully utilizing this type of technology, and a simulation tool plays an important role in the virtual design, that the performance of the injector is evaluated to reach the optimized design. The virtual test methodology using CFD to capture the fluid dynamics of the injector internal flow has been previously developed and validated for quantifying the dosing rate of the test injector. In this study, the capability of the virtual test methodology was extended to determine the spray angle of the test injector, and the effect of the manufacturing process on the injector internal nozzle flow characteristics was investigated using the enhanced virtual test methodology. Several variations of injector key geometric

Lu, Meng-Huang, Lacin, Figen, McAninch, Daniel, Yang, Frank

Next Generation All in One Close-Coupled Urea-SCR System

2015-01-099404/14/2015

Diesel engines provide a solution for the reduction of carbon dioxide (CO2) from motor vehicles. For diesel engines, however, technology to reduce nitrogen oxide (NOx) emissions is essential. This report focuses on Urea - Selective Catalytic Reduction (SCR) as an aftertreatment system for NOx reduction. The NOx conversion performance of SCR catalyst depends on exhaust gas temperature and the NO2/NOX ratio. In order to raise the NO2/NOX ratio, it is essential to raise the temperature of oxidation catalyst. For these purposes, it is necessary to raise the temperature of oxidation catalyst and SCR catalyst to high level in order to enhance NOx conversion. Temperature rising is implemented by in-cylinder fuel injection (post-injection). Consequently, degraded fuel economy becomes an issue at low vehicle speeds that cannot be expected to raise the temperature in catalyst, and particularly in the case of conventional SCR system that is located under the vehicle floor (Under-Floor SCR: UF/SCR

Kojima, Hiroyuki, Fischer, Michael, Haga, Hisao, Ohya, Naoki, Nishi, Kensuke, Mito, Takuya, Fukushi, Naoko

OBD Diagnostic Strategies for LEVIII Exhaust Gas Aftertreatment Concepts

2015-01-104004/14/2015

Upcoming motor vehicle emission regulations, such as California's LEVIII, continue to tighten emission limitations in diesel vehicles. These increasingly challenging emission requirements will be met by improving the combustion process (reducing engine-out emissions), as well as improving the exhaust gas aftertreatment efficiency. Furthermore, intricate On-Board Diagnostics (OBD) systems are required to properly diagnose and meet OBD regulation requirements for complex aftertreatment systems. Under these conditions, current monitoring strategies are unable to guarantee reliable detection of partially failed systems. Additionally, new OBD regulations require aftertreatment systems to be diagnosed as a whole. This paper covers potential OBD strategies for LEVIII aftertreatment concepts with regard to regulation compliance and robustness, while striving to use existing sensor concepts.

Nanjundaswamy, Harsha K., Deussen, Joel, Van Sickle, Roger, Tomazic, Dean, Szailer, Tamas, Franke, Michael, Kotter, Matthias, Koerfer, Thomas

A Study of LNT & Urea SCR on DPF System to Meet the Stringent Exhaust Emission Regulation

2014-01-281010/13/2014

In diesel engine development, the new technology is coming out to meet the stringent exhaust emission regulation. The regulation demands more eco-friendly vehicles. Euro6c demands to meet not only WLTP mode, but also RDE(Real Driving Emission). In order to satisfy RDE mode, the new technology to reduce emissions should cover all operating areas including High Load & High Speed. It is a big challenge to reduce NOx on the RDE mode and a lot of DeNOx technologies are being developed. So the new DeNOx technology is needed to cover widened operating area and strict acceleration / deacceleration. The existing LNT(Lean NOx Trap) and Urea SCR(Selective Catalytic Reduction) is necessary to meet the typical NEDC or WLTP, but the RDE mode demands the powerful DeNOx technology. Therefore, the LNT & Urea SCR on DPF was developed through this study. This complex new technology consists of new catalysts(to reduce emissions), insulation(to improve fuel economy, and catalytic performance), and logical

Joo, Kihyung, Park, Jin Woo, Lee, Jin-ha, Kim, Seok-Jae, Yoo, Seungbeom

Development and Implementation of a Mapless, Model Based SCR Control System

2014-01-905007/01/2014

Various engine platforms employ Selective Catalytic Reduction (SCR) technology to reduce the tail pipe emissions of oxides of nitrogen (NOx) from diesel engines as part of an overall strategy to comply with the emission regulations in place in various countries. High levels of NOx conversion (greater than 98%) in SCR aftertreatment may provide operating margin to increase overall fuel efficiency. However, to realize the potential fuel efficiency gains, the SCR technology employed should achieve high NOx conversion with limited reductant slip over transient application cycles in addition to steady state operation. A new approach to SCR controls was developed and implemented. This approach does not rely on any maps to determine the amount of urea solution to be dosed, thus significantly reducing calibration and development time and effort when implementing the SCR technology on multiple engine platforms and applications. In addition, the controls technique is completely model based and

Chavannavar, Praveen

Secondary Fuel Injection Characterization of a Diesel Vaporizer for Active DPF Regeneration

SAE-PAPER-2014-01-149404/01/2014

Secondary fuel injection is applied to facilitate active soot management of the particulate filter within diesel aftertreatment systems, avoiding concerns with fuel delivery via in-cylinder post-injection. System performance is dependent on the thermo-fluid interactions of the injected fuel with the exhaust stream, with the intent of having more fully vaporized fuel and a well-mixed air-fuel mixture at the inlet of the oxidation catalyst for uniform thermal distribution as it exothermically reacts. Pre-heating the fuel with a diesel vaporizer prior to its delivery into the exhaust enables improved system performance, reducing droplet sizes and mixing demands. A diesel vaporizer is applied within the exhaust of a medium duty truck application, and the response of the catalyst is characterized across a variety of conditions. Cross-sectional measurements at the catalyst and filter outlet are described, including gas velocity, temperature, and HC concentration, and the effect of poor fuel

Hein, Eric, Kotrba, Adam, Inclan, Tobias, Bright, Andrew

Catalytic NOx Control Technologies for Diesel & GDI Engines Web Seminar RePlay

PD331237ON03/05/2014

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. This three session web seminar will examine the various catalytic processes for lean burn applications, including Selective Catalytic NOx Reduction (SCR), NOx Trap Technologies (i.e. LNT, NSR), and the combination of SCR, NOx Trap and Hydrocarbon NOx Reduction (LNC). It will focus in on SCR NOx fundamentals, equipping participants with the basic concepts for NOx control and important design

Comparative Urban Drive Cycle Simulations of Light-Duty Hybrid Vehicles with Gasoline or Diesel Engines and Emissions Controls

2013-01-158504/08/2013

We summarize results from comparative simulations of hybrid electric vehicles with either stoichiometric gasoline or diesel engines. Our simulations utilize previously published models of transient engine-out emissions and models of aftertreatment devices for both stoichiometric and lean exhaust. Fuel consumption and emissions were estimated for comparable gasoline and diesel light-duty hybrid electric vehicles operating over single and multiple urban drive cycles. Comparisons between the gasoline and diesel vehicle fuel consumptions and emissions were used to identify potential advantages and technical barriers for diesel hybrids.

Gao, Zhiming, Daw, C. Stuart, Smith, David E.

DOC Temperature Control for Low Temperature Operating Ranges with Post and Main Injection Actuation

2013-01-158004/08/2013

In a typical diesel engine exhaust aftertreatment system consisting of a diesel oxidation catalyst (DOC), a diesel particulate filter (DPF) and a selective catalytic reduction (SCR) system the main purpose of the DOC, besides the oxidation of CO to CO₂, is the oxidation of NO to NO₂. The NO to NO₂ conversion is an essential contribution for the downstream SCR system because the fast SCR reaction which provides the highest conversion rates of NOx to H₂O and N₂ works well only under roughly equal concentrations of NO and NO₂. The typical amount of NO to NOx ratio produced by the engine is about 0.95, hence the DOC is necessary to decrease this coefficient close to 0.50. Due to the temperature dependency of the DOC reaction mechanism the oxidation of NO to NO₂ takes only place sufficiently if the temperature of the DOC is higher than 200°C, which, however, cannot be reached during low engine speed and low load situations. As a consequence, under these circumstances the whole reduction

Stadlbauer, Stephan, Waschl, Harald, Schilling, Alexander, del Re, Luigi

Simulated Fuel Economy and Emissions Performance during City and Interstate Driving for a Heavy-Duty Hybrid Truck

2013-01-103304/08/2013

We compare the simulated fuel economy and emissions for both conventional and hybrid class 8 heavy-duty diesel trucks operating over multiple urban and highway driving cycles. Both light and heavy freight loads were considered, and all simulations included full aftertreatment for NOx and particulate emissions controls. The aftertreatment components included a diesel oxidation catalyst (DOC), urea-selective catalytic NOx reduction (SCR), and a catalyzed diesel particulate filter (DPF). Our simulated hybrid powertrain was configured with a pre-transmission parallel drive, with a single electric motor between the clutch and gearbox. A conventional heavy duty (HD) truck with equivalent diesel engine and aftertreatment was also simulated for comparison. Our results indicate that hybridization can significantly increase HD fuel economy and improve emissions control in city driving. However, there is less potential benefit for HD hybrid vehicles during highway driving. A major factor behind

Daw, C. Stuart, Gao, Zhiming, Smith, David E., Laclair, Tim J., Pihl, Josh A., Edwards, K. Dean

Adaptive Temperature Control for Diesel Particulate Filter Regeneration

2013-01-051704/08/2013

The regeneration process of a Diesel Particulate Filter (DPF) consists of an increase in the engine exhaust gas temperature by using post injections and/or exhaust fuel injection during a period of time in order to burn previously trapped soot. The DPF regeneration is usually performed during a real drive cycle, with continuously changing driving conditions. The quantity of post injection/exhaust fuel to use for regeneration is calculated using a combination of an open loop term based on engine speed, load and exhaust gas flow and a closed loop term based on an exhaust gas temperature target and the feedback from a number of sensors. Due to the nature of the system and the slow response of the closed loop term for correcting large deviations, the authority of the fuel calculation is strongly biased to the open loop. However, the open loop fuel calculation might not be accurate enough to provide adequate temperature tracking due to several disturbances in the system. This paper

Castellano, Javier, Chaudhari, Anita, Bromham, Jim

Development of an Urea Supply System for the SCR Catalyst

2013-26-004701/09/2013

The increase in the fuel price and more stringent regulations on greenhouse gases (CO2) make the engine compression ignition technology even more attractive in the context of internal combustion engines. This is because the modern turbocharged direct injection engines, with the common rail fuel system, are characterized by high combustion efficiency and power density, that make them particularly suitable both for applications on and off road. On the other hand, the compression ignition engines are subject to a heavy technological developments to meet the more stringent regulations on emissions of exhaust pollutants, especially PM and NOx. The adopted technologies have two main approaches, on the combustion and on the exhaust gas aftertreatment. The measures applied for combustion can reduce emissions, but with the risk of penalizing the other engine performances, such as noise, power output and fuel consumption. Instead, the technologies of exhaust gases treatment may allow the over

De Cesare, Matteo, Osbat, Giovanni, Sgatti, Stefano, Battistoni, Michele

Design of Durable Vanadium - SCR Catalyst Systems for Heavy - Duty Diesel Applications

2013-26-004901/09/2013

The emission regulations for mobile applications become stricter in Euro-IV to Euro-VI levels. Carbon monoxide and hydrocarbon can be removed by efficient Diesel Oxidation Catalysts (DOC) but Particulate Matter (PM) and NOx are more demanding requiring the use of active methods (urea-SCR and DPF) which will be world-wide implemented in the 2010's. Durable, coated V-SCR catalysts are based on stabilized raw materials and tailored preparation methods. Coated V2O5/TiO2-WO3 catalysts (ceramic 300/400 cpsi and metallic 500/600 cpsi) were evaluated by laboratory and engine bench experiments. Traditional V-SCR catalysts are durable up to about 600°C and have a high efficiency at 300°C-500°C. SCR activities were tailored to be higher also at 200°C-300°C or 500°C-600°C. The use of thermal stabilizers or the vanadium loading variation enabled the changes in operation window and stability. The stabilized V-SCR catalyst kept the SCR activity also after ageing at 600°C-650°C when the reference lost

Maunula, Teuvo, Viitanen, Arto, Kinnunen, Toni, Kanniainen, Kauko

Simulation of Catalytic Oxidation and Selective Catalytic NOx Reduction in Lean-Exhaust Hybrid Vehicles

2012-01-130404/16/2012

We utilize physically-based models for diesel exhaust catalytic oxidation and urea-based selective catalytic NOx reduction to study their impact on drive cycle performance of hypothetical light-duty diesel-powered hybrid and plug-in hybrid vehicles (HEVs and PHEVs). The models have been implemented as highly flexible SIMULINK block modules that can be used to study multiple engine-aftertreatment system configurations. The parameters of the NOx reduction model have been adjusted to reflect the characteristics of commercially available Cu-zeolite catalysts, which are of widespread current interest. We demonstrate application of these models using the Powertrain System Analysis Toolkit (PSAT) software for vehicle simulations, along with a previously published methodology that accounts for emissions and temperature transients in the engine exhaust. Our results illustrate that the DOC-SCR combination can reduce CO, HC and NOx emissions without creating a significant direct fuel penalty, but

Gao, Zhiming, Daw, C. Stuart, Chakravarthy, V. Kalyana

Controlling Particulate Matter Emissions in Vehicles Using Different Strategies under the Heavy-Duty Test Cycle

2012-01-088504/16/2012

Since 1997 in Belgium, the market share of vehicles equipped with diesel engine has grown up from 50% to nearly 80%. Most of the drivers are using diesel cars for private or company purposes and gasoline powered engine vehicles sales dropped dramatically since then. This evolution is clearly a game-changer regarding the type of regulated emissions we can find as dominant. Tests and analysis for this work focused on diesel passenger cars and one of the main drivers for that was the great demand of new cars fitted with exhaust aftertreatment devices (DPF, DOC, LBC etc.). In this paper the performance of soot filters were measured and presented, based not on the NEDC but on the heavy duty 13-Mode test cycle which emphasize mainly at low-speed driving conditions, such as all passenger cars are running currently, and is also characterized by low average engine loads and low exhaust temperatures. Two modern test cars were used and tested under the same operational conditions on a chassis

Oliveira, Luis Miguel, Savvidis, Dimitrios, Pecqueur Sr, Mark

Characterization of a New Advanced Diesel Oxidation Catalyst with Low Temperature NO _x Storage Capability for LD Diesel

2012-01-037304/16/2012

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. One possible solution to improve the low temperature behavior, is the use of newly developed Advanced Diesel Oxidation Catalysts (A-DOC) which are capable to store NOx at low exhaust temperatures (typical of urban driving conditions) when SCR efficiency is low, and to release the stored NOx at higher temperatures (i.e., during extra-urban driving conditions) where the urea injected is effectively forming ammonia for the subsequent

Millo, Federico, Vezza, Davide

Designing quiet off-highway equipment

12OFHD0202_0202/02/2012

OEMs and suppliers are using new materials and innovative designs to reduce NVH for both vehicle operators and the environment. Off-highway vehicles can generate a lot of noise. Many improvements are being made to engines, structures, and systems related to NVH. Whether in smaller vehicles working in urban areas and/or enclosed spaces, or in larger vehicles, quieter systems will eliminate the need for hearing protection and cut down on fatigue caused by long exposure to high noise or vibration levels.

Sniderman, Debbie

Fuel Injector Optimization for Diesel Aftertreatment Systems Coupled with Exhaust Aftertreatment System Performance on a Heavy-Duty Diesel Engine Powered Vehicle

10VARCV0711/17/2011

Exhaust system fuel injection is required for many diesel engine aftertreatment systems including diesel particulate filter (DPF) systems, fuel reforming systems and lean NOx trap (LNT) systems. The design objective of this work was to develop exhaust system fuel injectors that promoted high aftertreatment conversion efficiencies with low fuel usage. A fuel injection system utilizing a pulse-width modulated (PWM) pressure swirl atomizer was first evaluated in a spray laboratory using drop size and spray patternation diagnostic equipment. The fuel system was later evaluated as part of an aftertreatment system consisting of fuel reformer, LNT, DPF and selective catalytic reduction (SCR) catalysts. Three system fuel injectors with high turndown ratios (16.5:1 to 25:1) were developed to provide fuel flow ranges of 10 to 250 grams per minute, 30 to 500 grams per minute and 50 to 1000 grams per minute. The fuel sprays consisted of droplet Sauter mean diameters (SMD) that ranged between 55 to

Bamber, Dan

De-NOx Characteristics of a Combined System of LNT and SCR according to Space Velocity

2011-01-208808/30/2011

The purpose of this paper is to investigate the adsorption and desorption characteristics of only LNT and SCR catalysts with respect to SV (Space Velocity) and the de-NOx performance of a combined system of LNT and SCR according to the SV. The adsorption time to reach NOx concentration of 500 ppm at SV = 14,000 1/h of the LNT catalyst was about 1,000 sec. The physically and chemically absorbed NH₃ on the SCR catalyst desorbed in same concentration though various SVs. The NOx conversion of the LNT decreased with SV increased in range of 350° or lower temperature, the formation quantity of NH₃ increased as SV increased in the lower temperature range. The NOx conversion of the SCR with SV = 14,000 1/h showed 95% at 320°, the effect of SV on the NOx conversion was not so much. The NOx conversion of the combined system of LNT and SCR with fresh catalysts appeared maximum value of 70% and hydrothermal aging at 900° decreased about to 25% below range of 300°. And the hydrothermally aged

Seo, Choong-Kil, Kim, Hwanam, Choi, Byungchul

Impact of Biodiesel Impurities on the Performance and Durability of DOC, DPF and SCR Technologies

2011-01-113604/12/2011

It is estimated that operating continuously on a B20 fuel containing the current allowable ASTM specification limits for metal impurities in biodiesel could result in a doubling of ash exposure relative to lube-oil-derived ash. The purpose of this study was to determine if a fuel containing metals at the ASTM limits could cause adverse impacts on the performance and durability of diesel emission control systems. An accelerated durability test method was developed to determine the potential impact of these biodiesel impurities. The test program included engine testing with multiple DPF substrate types as well as DOC and SCR catalysts. The results showed no significant degradation in the thermo-mechanical properties of cordierite, aluminum titanate, or silicon carbide DPFs after exposure to 150,000 mile equivalent biodiesel ash and thermal aging. However, exposure of a cordierite DPF to 435,000 mile equivalent aging resulted in a 69% decrease in the thermal shock resistance parameter. It

Williams, Aaron, McCormick, Robert, Luecke, Jon, Brezny, Rasto, Geisselmann, Andreas, Voss, Kenneth, Hallstrom, Kevin, Leustek, Matthew, Parsons, Jared, Abi-Akar, Hind

The Study of NOx Reduction Using Plasma-assisted SCR System for a Heavy Duty Diesel Engine

2011-01-031004/12/2011

To reduce NOx emissions from a heavy-duty engine at low exhaust temperature conditions, the plasma-assisted SCR (Selective Catalytic Reduction) system was evaluated. The plasma-assisted SCR system is mainly composed of an ammonia gas supply system and a plasma reactor including a pellet type SCR catalyst. The preliminary test with simulated gases of diesel exhaust showed an improvement in the NOx reduction performance by means of the plasma-assisted SCR system, even below 150°C conditions. Furthermore, NOx reduction ratio was improved up to 77% at 110°C with increase in the catalyst volume. Also NOx emissions from a heavy-duty diesel engine over the transient test mode in Japan (JE05) were reduced by the plasma-assisted SCR system. However, unregulated emissions, e.g., aldehydes, were increased with the plasma environment. This paper reports the advantages and disadvantages of the plasma-assisted SCR system for a heavy-duty diesel engine.

Sato, Shinya, Kawada, Yoshihiro, Sato, Satoshi, Hosoya, Mitsuru, Mizuno, Akira

Lean Gasoline Engine Reductant Chemistry During Lean NOx Trap Regeneration

2010-01-226710/25/2010

Lean NOx Trap (LNT) catalysts can effectively reduce NOx from lean engine exhaust. Significant research for LNTs in diesel engine applications has been performed and has led to commercialization of the technology. For lean gasoline engine applications, advanced direct injection engines have led to a renewed interest in the potential for lean gasoline vehicles and, thereby, a renewed demand for lean NOx control. To understand the gasoline-based reductant chemistry during regeneration, a BMW lean gasoline vehicle has been studied on a chassis dynamometer. Exhaust samples were collected and analyzed for key reductant species such as H₂, CO, NH₃, and hydrocarbons during transient drive cycles. The relation of the reductant species to LNT performance will be discussed. Furthermore, the challenges of NOx storage in the lean gasoline application are reviewed.

Parks, James E., Prikhodko, Vitaly, Partridge, William, Choi, Jae-Soon, Norman, Kevin, Huff, Shean, Chambon, Paul

Passive Ammonia SCR System for Lean-burn SIDI Engines

2010-01-036604/12/2010

Lean-burn Spark Ignition Direct Injection (SIDI) engines offer potential fuel economy savings, however, lack of cost-effective lean NOx aftertreatment systems has hindered its broad application. Lean NO Trap (LNT) and Urea Selective Catalytic Reduction (SCR) technologies have been widely investigated as possible solutions, but they both have considerable drawbacks. LNT catalysts suffer from high Platinum Group Metals (PGM) cost, poor thermal durability, sulfur poisoning and active SO regeneration requirements. Urea SCR systems require a secondary fluid tank with an injection system, resulting in added system cost and complexity. Other concerns for urea SCR include potential freezing of the urea solution and the need for customers to periodically fill the urea reservoir. In this paper we report a low-cost, high efficiency concept that has the potential to be a key enabler for lean-burn gasoline engines. The aftertreatment system includes a close-coupled three-way catalytic converter

Li, Wei, Perry, Kevin L., Narayanaswamy, Kushal, Kim, Chang Hwan, Najt, Paul

Development of an Ultra-Low Concentration N2O Analyzer Using Quantum Cascade Laser (QCL)

2010-01-129104/12/2010

Green House Gas (GHGs) emission reduction has gained large prominence globally due to the climate change. Nitrous Oxide (N₂O) emission from transportation has significant share on global warming. Therefore, an instrument for sensing ultra-low level of N₂O is a key global demand. In this study, development of an instrument based on the Quantum Cascade Laser (QCL) has been attempted for measuring ultra-low level N₂O in automobile exhaust gas sampled in a sample storage bag. The QCL can emit coherent lights in a mid-infrared (Mid-IR) region where N₂O shows strong absorption peak. This absorption peak can be detected by an MCT (Mercury Cadmium Tellurium) type photovoltaic detector. The optics configuration used in this study can give a superfine resolution of the Mid-IR spectrum such as 0.002 cm-₁ in the target wavelength band. Therefore, utilizing this spectrometer, measurement of ultra-low level N₂O is possible without interference of co-existing gases. The instrument developed has been

Montajir, Rahman

Investigation on NOx Storage Characteristics and Aging Influence of Lean NOx Trap Model Catalyst BaO-Pt/Al2O3

2010-01-036404/12/2010

Barium oxide (BaO) and platinum (Pt) are the key components in lean NOx trap (LNT) catalysts. Previous work has demonstrated that highly dispersed and bulk-like BaO species have low-temperature (LT) and high-temperature (HT) release features for stored nitrogen dioxide (NO₂). To better understand the roles of both BaO and Pt, a series of BaO/Al₂O₃ and BaO-Pt/Al₂O₃ were prepared and used to investigate the release characteristics of stored NO₂. Two typical BaO-Pt/Al₂O₃ catalysts having 75% and 44% of dispersed BaO, respectively, were aged and used for both the static NO₂ storage and the dynamic NOx elimination by lean-rich cyclic reactions. Results showed that bulk-like BaO plays a lesser role in storing NO₂ than does dispersed BaO. Pt inhibits the formation of nitrates and thus decreases NO₂ storage capacity (NSC) as Pt can catalyze the release, particularly for NO₂ species stored on bulk-like BaO. Aging in the range of 750-950°C resulted in a decrease of NSC but the HT release peak

Chen, Xiaoyin, Schwank, Johannes W.

Review of Diesel Emissions and Control

2010-01-030104/12/2010

This review summarizes the latest developments in diesel emissions regarding regulations, engines, NOx (nitrogen oxides) control, particulate matter (PM) reductions, and hydrocarbon (HC) and CO oxidation. Regulations are advancing with proposals for PN (particle number) regulations that require diesel particulate filters (DPFs) for Euro VI in 2013-14, and SULEV (super ultra low emission vehicle) fleet average light-duty (LD) emissions likely to be proposed in California for ~2017. CO₂ regulations will also impact diesel engines and emissions, probably long into the future. Engine technology is addressing these needs. Heavy-duty (HD) research engines show 90% lower NOx at the same PM or fuel consumption levels as a reference 2007 production engine. Work is starting on HD gasoline engines with promising results. In light duty (LD), engine downsizing is progressing and deNOx is emerging as a fuel savings strategy. Much has recently been reported on optimized selective catalytic reduction

Johnson, Timothy V.

Ammonia Production and Utilization in a Hybrid LNT+SCR System

2009-01-273911/02/2009

A hybrid LNT+SCR system is used to control NOx from a light-duty diesel engine with in-cylinder regeneration controls. A diesel oxidation catalyst and diesel particulate filter are upstream of the LNT and SCR catalysts. Ultraviolet (UV) adsorption spectroscopy performed directly in the exhaust path downstream of the LNT and SCR catalysts is used to characterize NH3 production and utilization in the system. Extractive exhaust samples are analyzed with FTIR and magnetic sector mass spectrometry (H2) as well. Furthermore, standard gas analyzers are used to complete the characterization of exhaust chemistry. NH3 formation increases strongly with extended regeneration (or “over regeneration”) of the LNT, but the portion of NOx reduction occurring over the SCR catalyst is limited by the amount of NH3 produced as well as the amount of NOx available downstream of the LNT. Control of lean-rich cycling parameters enables control of the ratio of NOx reduction between the LNT and SCR catalysts

Parks, Jim, Prikhodko, Vitaly

Hydrocarbon Deactivation of a Hydrocarbon SCR Catalyst

2009-01-277911/02/2009

At the current state of diesel engine technology, all diesel engines require some sort of NOx control device to comply with Tier II Bin 5 light-duty or 2010 heavy-duty NOx emission standards. Selective Catalytic Reduction of NOx with hydrocarbons (HC-SCR) to reduce NOx from diesel exhaust emissions is an attractive technology for lean NOx control, especially when diesel fuel is used as the reductant. However, it has been reported that when diesel fuel is used as the reductant catalyst deactivation occurred. Even though this kind of deactivation is reversible at high enough temperatures, it is a deficiency that needs to be overcome for the successful implementation of the technology. We studied the HC-SCR catalyst deactivation using diesel fuel as the reductant. The variables investigated included catalyst temperature, HC:NOx ratio, NOx concentration, and space velocity. The results showed that one single parameter can be used to measure the catalyst deactivation: the HC-SCR activity

Cheng, Shi-wai S., Mulawa, Patricia A.

Lean NOx Trap Aftertreatment Technology Impact on Engine Oil Dilution

2009-24-015309/13/2009

Euro 6 European legislation emission limits, expected to be introduced around the 2014 timeframe, Lean NOx Trap (LNT) Aftertreatment technology is today considered one the of candidate technology to allow diesel Engine to meet the future Euro 6 limit. The working principle of the LNT is based on its capability to store the NOx engine out during the normal lean (excess of Oxygen) phase operation condition of the Diesel engine. The NOx will be then reduced in a dedicated regeneration phase which consist in creating for relatively short time a rich exhaust gas condition inside the LNT. The LNT regeneration strategy lead to run a Diesel engine with a rich mixture out of the combustion as a Gasoline engine. This can be obtained using advanced air and fuel management. The fuel management implicate the use of delayed injections (after and/or post injections) which can have a direct impact on oil dilution. In this paper, an experimental assessment of the additional oil dilution phenomenon

Cardone, M., Senatore, A., Buono, D., Cipolla, G., Chianale, A., Leo, A.

Impact and Prevention of Ultra-Low Contamination of Platinum Group Metals on SCR Catalysts Due to DOC Design

2009-01-062704/20/2009

Diesel aftertreatment systems configured with a diesel oxidation catalyst (DOC) upstream of an urea selective catalytic reduction (SCR) catalyst run the risk of precious metal contamination. During active diesel particulate filter (DPF) regeneration events, the DOC bed temperature can reach up to 850°C. Under these conditions, precious metal (especially Pt) can be volatized and then deposited on a downstream SCR catalyst. In this paper, the impact of ultra-low contamination of platinum group metals (PGM) on the SCR catalyst was studied. A method based on precious metal volatilization of a Pt-rich DOC at 850°C and under lean gas conditions was employed to contaminate downstream FeSCR and CuSCR formulations. The contamination resulted in poor NOx conversion (via NOx remake) and excessive N2O formation. The precious metal volatilization method was employed to screen various Pt/Pd based DOCs to avoid contamination of the downstream FeSCR. A correlation was developed that showed a reduction

Cavataio, Giovanni, Jen, Hung-Wen, Girard, James W., Dobson, Douglas, Warner, James R., Lambert, Christine K.

Opportunities and Challenges for Blended 2-Way SCR/DPF Aftertreatment Technologies

2009-01-027404/20/2009

Diesel engines offer better fuel economy compared to their gasoline counterpart, but simultaneous control of NOx and particulates is very challenging. The blended 2-way SCR/DPF is recently emerging as a compact and cost-effective technology to reduce NOx and particulates from diesel exhaust using a single aftertreatment device. By coating SCR catalysts on and inside the walls of the conventional wall-flow filter, the 2-way SCR/DPF eliminates the volume and mass of the conventional SCR device. Compared with the conventional diesel aftertreatment system with a SCR and a DPF, the 2-way SCR/DPF technology offers the potential of significant cost saving and packaging flexibility. In this study, an engine dynamometer test cell was set up to repeatedly load and regenerate the SCR/DPF devices to mimic catalyst aging experienced during periodic high-temperature soot regenerations in the real world. The emission reduction performances of the engine-aged 2-way SCR/DPF devices with various SCR

He, Yongsheng, Brown, David B., Lu, Shuguang, Paratore, Michael J., Li, Jianwen

Concept Study for NOx Aftertreatment Systems for Europe

2009-01-063204/20/2009

While the market share for diesel engines for LD vehicles in North America is still negligible, the market share in Europe has grown continuously in the past years and has reached a level of 50% in 2008. Until now, it has been possible to fulfill the limits for nitrogen oxides (NOx) in Europe without using an active NOx aftertreatment system. With the introduction of EU6, most new diesel applications will now require NOx aftertreatment. One of the possible technologies for the reduction of nitrogen oxides in lean exhaust gas is the NOx storage catalyst (or lean NOx trap, LNT) which is utilized in the current Tier 2 Bin 5/8 diesel systems from Daimler and VW. For heavier applications urea SCR is the preferred technology to meet NOx legislation limits. For EU5 most of the exhaust aftertreatment systems include a DOC-DPF system in order to meet targets for CO, HC and particles. For many EU 6 applications an active NOx aftertreatment system will be necessary and the fuel economy will be

Rohr, F., Grißtede, I., Bremm, S.

NOx Performance of an LNT+SCR System Designed to Meet EPA 2010 Emissions: Results of Engine Dynamometer Emission Tests

2008-01-264210/07/2008

The paper covers the NOx performance evaluation of an LNT + SCR system designed to meet the 2010 on-highway heavy-duty (HD) US EPA emission standards. The system combines a fuel reformer catalyst (REF), lean NOx trap (LNT), diesel particulate filter (DPF), and selective catalytic reduction (SCR) in series, to reduce engine-out NOx and PM. System NOx reduction performance was verified in an engine dynamometer test cell, using a 2007 7.6L medium-duty engine. System NOx performance was characterized using fresh LNT and SCR along with hydrothermal aged LNT and fresh SCR. Test results show levels consistent with EPA 2010 limits under various test conditions. Catalysts performance was characterized at eight steady engine-operating conditions (A100, B50, B75, A75, B100, C100, C75, C50, across a 13-mode Supplemental Emission Test (SET), and an on-highway Heavy Duty Federal Test Procedure (HD-FTP). System level NOx conversion ranged from 84 to 99%, SCR contributing between 8 - 25% of total

Dykes, Erik C.

Architecture Design and Analysis of Diesel Engine Exhaust Aftertreatment System and Comparative Study with Close-coupled DOC-DPF System

2008-01-175606/23/2008

In response to the emissions standards for diesel engines, it is essential to have separate aftertreatment devices for controlling the specific tailpipe emissions like HC, CO, NOx, and particulate matter. An advanced diesel exhaust aftertreatment system consists of channel-flow catalytic converters such as diesel oxidation catalyst (DOC), selective catalyst reduction (SCR) and wall-flow diesel particulate filters (DPF) each with discrete functions. Because of this multi-component aftertreatment system configuration, there are an increase in system complexity, development time and cost for doing experiments in order to evaluate various options and find the optimum aftertreatment system architecture. The objective of this work is the development and application of an integrated aftertreatment system model including DOC, SCR, DPF and all connecting pipes. The study includes the baseline system performance, i.e. SCR forward system (DOC-SCR-DPF), DPF forward system (DOC-DPF-SCR), and DPF

Gurupatham, Anand, He, Yongsheng

Items per page:

1 – 50 of 93