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Video

SCR Deactivation Kinetics for Model-Based Control and Accelerated Aging Applications

2012-06-18
Selective Catalytic Reduction (SCR) catalysts are used to reduce NOx emissions from internal combustion engines in a variety 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 a Fe-zeolite formulation. This work describes NH3 storage capacity measurement data as a function of aging time and temperature. Addressing one objective of the work, these data can be used in model-based control algorithms to calculate the current NH3 storage capacity of an SCR catalyst operating in the field, based on time and temperature history. The model-based control then uses the calculated value for effective DEF control and prevention of excessive NH3 slip. Addressing a second objective of the work, accelerated thermal aging of SCR catalysts may be achieved by elevating temperatures above normal operating temperatures.
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

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

Overview of Southwest Research Institute Activities in Engine Technology R&D

2012-05-10
The worldwide drive to improved energy efficiency for engine systems is being supported by several engine R&D programs at Southwest Research Institute (SwRI). This research includes large programs in major-market engine categories, such as heavy-duty, non-road, and light-duty; and includes diesel, gasoline, and alternative fuel aspects. This presentation describes several key diesel engine programs being pursued under the SwRI Clean High Efficiency Diesel Engine consortium (CHEDE-VI), whose goal is to demonstrate future diesel technology exceeding 50% brake thermal efficiency. Additionally, SwRI?s High Efficiency Dilute Gasoline Engines consortium (HEDGE-II), is reviewed, where advanced technology for ultra-high efficiency gasoline engines is being demonstrated. The HEDGE-II program is built upon dilute gasoline engine research, where brake thermal efficiencies in excess of 42% are being obtained for engines applicable to the light-duty market. Presenter Charles E.
Technical Paper

The Effect of Hydrogen Enrichment on EGR Tolerance in Spark Ignited Engines

2007-04-16
2007-01-0475
Small (up to 1% by volume) amounts of hydrogen (H2) were added to the intake charge of a single-cylinder, stoichiometric spark ignited engine to determine the effect of H2 addition on EGR tolerance. Two types of tests were performed at 1500 rpm, two loads (3.1 bar and 5.5 bar IMEP), two compression ratios (11:1 and 14:1) and with two fuels (gasoline and natural gas). The first test involved holding EGR level constant and increasing the H2 concentration. The EGR level of the engine was increased until the CoV of IMEP was > 5% and then small amounts of hydrogen were added until the total was 1% by volume. The effect of increasing the amount of H2 on engine stability was measured along with combustion parameters and engine emissions. The results showed that only a very small amount of H2 was necessary to stabilize the engine. At amounts past that level, increasing the level of H2 had no or only a very small effect.
Technical Paper

The Potential for Achieving Low Hydrocarbon and NOx Exhaust Emissions from Large Light-Duty Gasoline Vehicles

2007-04-16
2007-01-1261
Two large, heavy light-duty gasoline vehicles (2004 model year Ford F-150 with a 5.4 liter V8 and GMC Yukon Denali with a 6.0 liter V8) were baselined for emission performance over the FTP driving cycle in their stock configurations. Advanced emission systems were designed for both vehicles employing advanced three-way catalysts, high cell density ceramic substrates, and advanced exhaust system components. These advanced emission systems were integrated on the test vehicles and characterized for low mileage emission performance on the FTP cycle using the vehicle's stock engine calibration and, in the case of the Denali, after modifying the vehicle's stock engine calibration for improved cold-start and hot-start emission performance.
Technical Paper

Performance Test Results of a New On Board Emission Measurement System Conformed with CFR Part 1065

2007-04-16
2007-01-1326
A new on-board portable emission measurement system (PEMS) for gaseous emissions has been designed and developed to meet CFR Part 1065 requirements. The new system consists of a heated flame ionization detector (HFID) for the measurement of total hydrocarbon, a heated chemiluminescence detector (HCLD) for the measurement of NOx, and a heated non-dispersive infra-red detector (HNDIR) for the measurement of CO and CO2. The oxygen interference and relative sensitivity of several hydrocarbon components have been optimized for the HFID. The CO2 and H2O quenching effect on the HCLD have been compensated using measured CO2 and H2O concentration. The spectral overlap and molecular interaction of H2O on the HNDIR measurement has also been compensated using an independent H2O concentration measurement. The basic performance of the new on-board emission measurement system has been verified accordingly with CFR part 1065 and all of the performances have met with CFR part 1065 requirement.
Technical Paper

Analysis of a Hybrid Multi-Mode Hydromechanical Transmission

2007-04-16
2007-01-1455
A multi-mode hybrid hydromechanical transmission (HMT) with infinite variability is designed to meet the power transmission needs of medium duty on- and off-road vehicles. A hydraulic pump-motor assembly provides output speed and torque variability in an input coupled split power configuration. Dual planetary arrangements with two multiplate clutches allow multi-mode ratio change and combination of power from the mechanical and variable branches of the power path. Hydraulic accumulators offer hydraulic power assist during launch conditions and storage of reclaimed energy during braking events. Transmission kinematic, force and power flow analyses will be developed for the HMT and analyzed for suitability in a bus application. The resulting benefits and areas for improvement will be discussed.
Technical Paper

The Use of Radioactive Tracer Technology to Measure Real-Time Wear in Engines and Other Mechanical Systems

2007-04-16
2007-01-1437
Radioactive tracer technology (RATT™) is an important tool for measuring real-time wear in operating engines and other mechanical systems. The use of this technology provides important wear information that is not available by other, more conventional wear measurement methods. The technology has advanced to the point where several components can be interrogated simultaneously, and new methods have extended the method to materials that are normally not amenable to radioactive tracer evaluation. In addition, sensitivity has increased so that the onset of wear can be detected long before practical with non-tracer methods. This improves the ability to measure and determine cause and effect relationships, thus providing a better understanding of wear responses to specific operating conditions and to changes in operating conditions. This paper reviews the radioactive tracer process and recent improvements that have extended its reach in both automotive and non-automotive applications.
Technical Paper

Investigation of Alternative Combustion Crossing Stoichiometric Air Fuel Ratio for Clean Diesels

2007-07-23
2007-01-1840
Alternative combustion crossing stoichiometric air fuel ratio was investigated to utilize a 4-way catalyst system with LNT (lean NOx trap). The chemical mechanism of restricting soot formation reactions with low combustion temperature was combined with the physical mechanism of reducing smoke by lowering local equivalence ratio to enable low smoke rich and near rich combustion. A new combustion chamber for spatially and timely mixture formation phasing was developed to combine the two mechanisms and allow smooth EGR changing over a wide load range. Through this investigation, rich and near rich combustion to effectively utilize a 4-way catalyst system was realized. In addition, conditions suitable for LNT sulfur regeneration were realized from light to medium load.
Technical Paper

Engine Crankshaft Position Tracking Algorithms Applicable for Given Arbitrary Cam- and Crank-Shaft Position Signal Patterns

2007-04-16
2007-01-1597
This paper describes algorithms that can recognize and track the engine crankshaft position for arbitrary cam- and crank-shaft tooth wheel patterns in both steady-state and transient operating conditions. Crankshaft position tracking resolution is adjustable to accommodate different application requirements. The instantaneous crankshaft position information provided by the position tracking module form the basis for crankshaft angle domain (CAD) engine control and measurement functions such as precise injection / ignition controls and on-line cylinder pressure CAD analyses. The algorithms described make reconfiguration of the tracking module for different and arbitrary cam- and crank-shaft tooth wheel patterns very easy, which is valuable especially for prototyping engine control systems. The effectiveness of the algorithms is shown using test engines with different cam and crank signal patterns.
Technical Paper

AN AIRFLOW-DOMINANT CONTROL SYSTEM FOR FUTURE DIESEL ENGINES

2007-07-23
2007-01-2070
An airflow-dominant control system was developed to provide precise engine and exhaust treatment control with low air fuel ratio alternative combustion. The main elements of the control logic include a real-time state observer for in-cylinder oxygen mass estimation, a simplified packaging scheme for all air-handling and fueling parameters, a finite state machine for control mode switching, combustion control models to maintain robust alternative combustion during transients, and smooth rich/lean switching during lean NOx trap (LNT) regeneration without post injection. The control logic was evaluated on a passenger car equipped with a 4-way catalyst system with LNT and was instrumental in achieving US Tier II Bin 5 emission targets with good drivability and low NVH.
Technical Paper

US 2010 Emissions Capable Camless Heavy-Duty On-Highway Natural Gas Engine

2007-07-23
2007-01-1930
The goal of this project was to demonstrate a low emissions, high efficiency heavy-duty on-highway natural gas engine. The emissions targets for this project are to demonstrate US 2010 emissions standards on the 13-mode steady state test. To meet this goal, a chemically correct combustion (stoichiometric) natural gas engine with exhaust gas recirculation (EGR) and a three way catalyst (TWC) was developed. In addition, a Sturman Industries, Inc. camless Hydraulic Valve Actuation (HVA) system was used to improve efficiency. A Volvo 11 liter diesel engine was converted to operate as a stoichiometric natural gas engine. Operating a natural gas engine with stoichiometric combustion allows for the effective use of a TWC, which can simultaneously oxidize hydrocarbons and carbon monoxide and reduce NOx. High conversion efficiencies are possible through proper control of air-fuel ratio.
Technical Paper

Investigation of Alternative Combustion, Airflow-Dominant Control and Aftertreatment System for Clean Diesel Vehicles

2007-07-23
2007-01-1937
A new diesel engine system adopting alternative combustion with rich and near rich combustion, and an airflow-dominant control system for precise combustion control was used with a 4-way catalyst system with LNT (lean NOx trap) to achieve Tier II Bin 5 on a 2.2L TDI diesel engine. The study included catalyst temperature control, NOx regeneration, desulfation, and PM oxidation with and without post injection. Using a mass-produced lean burn gasoline LNT with 60,000 mile equivalent aging, compliance to Tier II Bin 5 emissions was confirmed for the US06 and FTP75 test cycles with low NVH, minor fuel penalty and smooth transient operation.
Technical Paper

Real-Time Transient and Steady-State Measurement of Oil Consumption for Several Production SI-Engines

2001-05-07
2001-01-1902
Real-time transient and steady-state oil consumption were measured on three SI-engines, applying two different ring-packs to each engine. Testing of multiple engines enables an assessment of the engine-to-engine variability in oil consumption. Testing of multiple ring-packs on each engine enables an assessment of the ring-pack-to-ring-pack variability in oil consumption. The oil consumption was measured by the Southwest Research Institute (SwRI) novel developed SO2-tracer technique, referred to as RTOC-III. An interesting finding is that the testing shows low engine-to-engine and ring-pack-to-ring-pack variability, in both steady-state, as well as in transient oil consumption. This suggests that the RTOC-III system did not introduce significant variability to the data. The testing results are experimental verification of a design and simulation exercise, in a field of scarcely published literature.
Technical Paper

Impact of Lubricant Oil on Regulated Emissions of a Light-Duty Mercedes-Benz OM611 CIDI-Engine

2001-05-07
2001-01-1901
The Partnership for a New Generation Vehicle (PNGV) has identified the compression-ignition, direct-injection (CIDI) engine as a promising technology in meeting the PNGV goal of 80 miles per gallon for a prototype mid-size sedan by 2004. Challenges remain in reducing the emission levels of the CIDI-engine to meet future emission standards. The objective of this project was to perform an initial screening of crank case lubricant contribution to regulated engine-out emissions, particularly when low particulate forming diesel fuel formulations are used. The test engine was the Mercedes-Benz OM611, the test oils were a mineral SAE 5W30, a synthetic (PAO based) SAE 5W30, and a synthetic (PAO based) SAE 15W50, and the test fuels were a California-like certification fuel and an alternative oxygenated diesel fuel.
Technical Paper

Vektron® 6913 Gasoline Additive NOX Evaluation Fleet Test Program

2001-05-07
2001-01-1997
A 28-vehicle fleet test was executed to verify and quantify the NOX emissions reductions achieved through the use of Infineum's Vektron 6913 gasoline additive. The fleet composition and experimental design were finalized in collaborative discussions with US Environmental Protection Agency (EPA) Office of Transportation & Air Quality (OTAQ) and consultation / advice from several major US automotive manufacturers. The test was conducted over a period of five months at Southwest Research Institute. Statistical analysis of the emissions data indicated a 10% average fleet reduction in NOX emissions without any negative impact on other criteria pollutants (CO, HC) or fuel economy.
Technical Paper

Dimethoxy Methane in Diesel Fuel: Part 1. The Effect of Fuels and Engine Operating Modes on Emissions of Toxic Air Pollutants and Gas/Solid Phase PAH

2001-09-24
2001-01-3627
The objective of this study was to quantify engine-out emissions of potentially toxic compounds from a modern diesel engine operated with different fuels including 15% v/v dimethoxy methane in a low sulfur diesel fuel. Five diesel fuels were examined: a low-sulfur, low-aromatic hydrocracked (∼1 ppm) fuel, the same low sulfur fuel containing 15% v/v dimethoxy methane, a Fischer-Tropsch fuel, a CARB fuel, and an EPA number 2 certification fuel. A DaimlerChrysler OM611 CIDI engine was controlled with a SwRI Rapid Prototyping Electronic Control system. The engine was operated over 4 speed-load modes. Each operating mode and fuel combination was run in triplicate. Thirty three potentially toxic compounds were measured for each fuel and mode.
Technical Paper

Dimethoxy Methane in Diesel Fuel: Part 2. The Effect of Fuels on Emissions of Toxic Air Pollutants and Gas/Solid Phase PAH Using a Composite Of Engine Operating Modes

2001-09-24
2001-01-3628
A weighted composite of four engine-operating modes, representative of typical operating modes found in the US FTP driving schedule, were used to compare engine-out emissions of toxic compounds using five diesel fuels. The fuels examined were: a low-sulfur low-aromatic hydrocracked diesel fuel, the same low-sulfur fuel containing 15% v/v dimethoxy methane, a Fischer-Tropsch fuel, a CARB fuel, and a EPA number 2 diesel certification fuel. A DaimlerChrysler OM611 CIDI engine was operated over 4 speed-load modes: mode 5, 2600 RPM, 8.8 BMEP; mode 6, 2300 RPM, 4.2 BMEP; mode 10, 2000 RPM, 2.0 BMEP; mode 11, 1500 RPM, 2.6 BMEP. The four engine operating modes were weighted as follows: mode 5, 25/1200; mode 6, 200/1200; mode 10, 375/1200; and mode 11, 600/1200. Each operating mode and fuel combination was run in triplicate.
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