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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.
Video

Catalyzed Particulate Filter Passive Oxidation Study with ULSD and Biodiesel Blended Fuel

2012-06-18
A 2007 Cummins ISL 8.9L direct-injection common rail diesel engine rated at 272 kW (365 hp) was used to load the filter to 2.2 g/L and passively oxidize particulate matter (PM) within a 2007 OEM aftertreatment system consisting of a diesel oxidation catalyst (DOC) and catalyzed particulate filter (CPF). Having a better understanding of the passive NO2 oxidation kinetics of PM within the CPF allows for reducing the frequency of active regenerations (hydrocarbon injection) and the associated fuel penalties. Being able to model the passive oxidation of accumulated PM in the CPF is critical to creating accurate state estimation strategies. The MTU 1-D CPF model will be used to simulate data collected from this study to examine differences in the PM oxidation kinetics when soy methyl ester (SME) biodiesel is used as the source of fuel for the engine.
Video

Vehicle Duty Cycles and Their Role in the Design and Evaluation of Advanced Vehicle Technologies

2012-04-10
Understanding in-use fleet operating behavior is of paramount importance when evaluating the potential of advanced/alternative vehicle technologies. Accurately characterizing real world vehicle operation assists in properly allocating advanced technologies, playing a role in determining initial payback period and return on investment. In addition, this information contributes to the design and deployment of future technologies as the result of increased awareness regarding tractive power requirements associated with typical operating behavior. In this presentation, the concept of vehicle duty cycles and their relation to advanced technologies will be presented and explored. Additionally, current research attempts to characterize school bus operation will be examined, and existing computational analysis and evaluation tools associated with these efforts discussed. Presenter Adam Duran, National Renewable Energy Laboratory
Technical Paper

The Effects of Different Input Excitation on the Dynamic Characterization of an Automotive Shock Absorber

2001-04-30
2001-01-1442
This paper deals with the dynamic characterization of an automotive shock absorber, a continuation of an earlier work [1]. The objective of this on-going research is to develop a testing and analysis methodology for obtaining dynamic properties of automotive shock absorbers for use in CAE-NVH low-to-mid frequency chassis models. First, the effects of temperature and nominal length on the stiffness and damping of the shock absorber are studied and their importance in the development of a standard test method discussed. The effects of different types of input excitation on the dynamic properties of the shock absorber are then examined. Stepped sine sweep excitation is currently used in industry to obtain shock absorber parameters along with their frequency and amplitude dependence. Sine-on-sine testing, which involves excitation using two different sine waves has been done in this study to understand the effects of the presence of multiple sine waves on the estimated dynamic properties.
Technical Paper

The Impact of Metal-free Solar Reflective Film on Vehicle Climate Control

2001-05-14
2001-01-1721
The air-conditioning system can significantly impact the fuel economy and tailpipe emissions of automobiles. If the peak soak temperature of the passenger compartment can be reduced, the air-conditioner compressor can potentially be downsized while maintaining human thermal comfort. Solar reflective film is one way to reduce the peak soak temperature by reducing the solar heat gain into the passenger compartment. A 3M non-metallic solar reflective film (SRF) was tested in two minivans and two sport utility vehicles (SUV). The peak soak temperature was reduced resulting in a quicker cooldown. Using these data, a reduction in air-conditioner size was estimated and the fuel economy and tailpipe emissions were predicted.
Technical Paper

Design and Transient Simulation of Vehicle Air Conditioning Systems

2001-05-14
2001-01-1692
This paper describes the need for dynamic (transient) simulation of automotive air conditioning systems, the reasons why such simulations are challenging, and the applicability of a general purpose off-the-shelf thermohydraulic analyzer to answer such challenges. An overview of modeling methods for the basic components are presented, along with relevant approximations and their effect on speed and accuracy of the results.
Technical Paper

The Effects of Natural Aging on Fleet and Durability Vehicle Engine Mounts from a Dynamic Characterization Perspective

2001-04-30
2001-01-1449
Elastomers are traditionally designed for use in applications that require specific mechanical properties. Unfortunately, these properties change with respect to many different variables including heat, light, fatigue, oxygen, ozone, and the catalytic effects of trace elements. When elastomeric mounts are designed for NVH use in vehicles, they are designed to isolate specific unwanted frequencies. As the elastomers age however, the desired elastomeric properties may have changed with time. This study looks at the variability seen in new vehicle engine mounts and how the dynamic properties change with respect to miles accumulated on fleet and durability test vehicles.
Technical Paper

Material Damping Properties: A Comparison of Laboratory Test Methods and the Relationship to In-Vehicle Performance

2001-04-30
2001-01-1466
This paper presents the damping effectiveness of free-layer damping materials through standard Oberst bar testing, solid plate excitation (RTC3) testing, and prediction through numerical schemes. The main objective is to compare damping results from various industry test methods to performance in an automotive body structure. Existing literature on laboratory and vehicle testing of free-layer viscoelastic damping materials has received significant attention in recent history. This has created considerable confusion regarding the appropriateness of different test methods to measure material properties for damping materials/treatments used in vehicles. The ability to use the material properties calculated in these tests in vehicle CAE models has not been extensively examined. Existing literature regarding theory and testing for different industry standard damping measurement techniques is discussed.
Technical Paper

Optimization of Vehicle Air Conditioning Systems Using Transient Air Conditioning Performance Analysis

2001-05-14
2001-01-1734
The National Renewable Energy Laboratory (NREL) has developed a transient air conditioning (A/C) system model using SINDA/FLUINT analysis software. It captures all the relevant physics of transient A/C system performance, including two-phase flow effects in the evaporator and condenser, system mass effects, air side heat transfer on the condenser/evaporator, vehicle speed effects, temperature-dependent properties, and integration with a simplified cabin thermal model. It has demonstrated robust and powerful system design optimization capabilities. Single-variable and multiple variable design optimizations have been performed and are presented. Various system performance parameters can be optimized, including system COP, cabin cool-down time, and system heat load capacity. This work presents this new transient A/C system analysis and optimization tool and shows some high-level system design conclusions reached to date.
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

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

Visualization techniques to identify and quantify sources and paths of exterior noise radiated from stationary and nonstationary vehicles

2000-06-12
2000-05-0326
In recent years, Nearfield Acoustical Holography (NAH) has been used to identify stationary vehicle exterior noise sources. However that application has usually been limited to individual components. Since powertrain noise sources are hidden within the engine compartment, it is difficult to use NAH to identify those sources and the associated partial field that combine to create the complete exterior noise field of a motor vehicle. Integrated Nearfield Acoustical Holography (INAH) has been developed to address these concerns: it is described here. The procedure entails sensing the sources inside the engine compartment by using an array of reference microphones, and then calculating the associated partial radiation fields by using NAH. In the second part of this paper, the use of farfield arrays is considered. Several array techniques have previously been applied to identify noise sources on moving vehicles.
Technical Paper

Development of a Desulfurization Strategy for a NOx Adsorber Catalyst System

2001-03-05
2001-01-0510
The aggressive reduction of future diesel engine NOx emission limits forces the heavy- and light-duty diesel engine manufacturers to develop means to comply with stringent legislation. As a result, different exhaust emission control technologies applicable to NOx have been the subject of many investigations. One of these systems is the NOx adsorber catalyst, which has shown high NOx conversion rates during previous investigations with acceptable fuel consumption penalties. In addition, the NOx adsorber catalyst does not require a secondary on-board reductant. However, the NOx adsorber catalyst also represents the most sulfur sensitive emissions control device currently under investigation for advanced NOx control. To remove the sulfur introduced into the system through the diesel fuel and stored on the catalyst sites during operation, specific regeneration strategies and boundary conditions were investigated and developed.
Technical Paper

Emission Reductions and Operational Experiences With Heavy Duty Diesel Fleet Vehicles Retrofitted with Continuously Regenerated Diesel Particulate Filters in Southern California

2001-03-05
2001-01-0512
Particulate emission control from diesel engines is one of the major concerns in the urban areas in California. Recently, regulations have been proposed for stringent PM emission requirements from both existing and new diesel engines. As a result, particulate emission control from urban diesel engines using advanced particulate filter technology is being evaluated at several locations in California. Although ceramic based particle filters are well known for high PM reductions, the lack of effective and durable regeneration system has limited their applications. The continuously regenerated diesel particulate filter (CRDPF) technology discussed in this presentation, solves this problem by catalytically oxidizing NO present in the diesel exhaust to NO2 which is utilized to continuously combust the engine soot under the typical diesel engine operating condition.
Technical Paper

Fuel Evaporation Parameter Identification during SI Cold Start

2001-03-05
2001-01-0552
The stochastic properties of continuous time model parameters obtained through discrete least squares estimation are examined. Particular attention is given to the application of estimating the fuel evaporation dynamics of a V-8 SI engine. The continuous time parameter distributions in this case are biased. The bias is shown to be a function of both measurement noise and sampling rate selection. Analysis and experimental results suggest that for each particular model, there is a corresponding optimum sampling rate. A bias compensation formula is proposed that improves the accuracy of least squares estimation without iterative techniques.
Technical Paper

Heavy-Duty Diesel Truck In-Use Emission Test Program for Model Years 1950 through 1975

2001-03-05
2001-01-1327
Criteria pollutants were measured from ten Class 7 and 8 (i.e., gross vehicle weights > 33,000 lb) heavy-duty diesel trucks with engine model years between 1953 and 1975. The data was used by EPA to estimate that period's particulate matter emission rates for these type engines and will be used to develop dose response relationships with existing epidemiological data. Particulate samples were analyzed for sulfate and volatile organic fraction. Carbon soot was estimated. The trucks had particulate emissions of 2 to 10 g/mi as compared to 1 to 6 g/mi for trucks with model year engines from 1975 through the mid-1980s, and less than 1 g/mi for post-1988 trucks.
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