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When performing catalyst modeling and parameter tuning it is desirable that the experimental data contain both transient and stationary points and can be generated over a short period of time. Here a method of creating such concentration transients for a full scale engine rig system is presented. The paper describes a valuable approach for changing the composition of engine exhaust gas going to a DOC (or potentially any other device) by conditioning the exhaust gas with an additional upstream DOC and/or SCR. By controlling the urea injection and the DOC bypass a wide range of exhaust compositions, not possible by only controlling the engine, could be achieved. This will improve the possibilities for parameter estimation for the modeling of the DOC.

In this paper, a model-based linear estimator and a non-linear control law for an Fe-zeolite urea-selective catalytic reduction (SCR) catalyst for heavy duty diesel engine applications is presented. The novel aspect of this work is that the relevant species, NO, NO2 and NH3 are estimated and controlled independently. The ability to target NH3 slip is important not only to minimize urea consumption, but also to reduce this unregulated emission. Being able to discriminate between NO and NO2 is important for two reasons. First, recent Fe-zeolite catalyst studies suggest that NOx reduction is highly favored by the NO 2 based reactions. Second, NO2 is more toxic than NO to both the environment and human health. The estimator and control law are based on a 4-state model of the urea-SCR plant. A linearized version of the model is used for state estimation while the full nonlinear model is used for control design.

Commercial vehicles carry more than 10 billion tons of goods - approximately 70 percent of all freight shipped and travel over 450 billion miles each year in the United States. These vehicles are the exclusive mode of delivery in over 75 percent of U.S. communities. Such utilization and dependency demand commercial vehicles be reliable, durable, and cost effective. The heart of these commercial vehicles (Classes 3-8) is the diesel engine. The widespread use of the diesel engine can be attributed to its reliability, durability, and cost effectiveness. However, the 2007 and 2010 EPA emissions regulations are creating significant challenges for diesel-powered commercial vehicles. Engine and vehicle manufacturers must strike a balance between emissions, performance, and affordability. A consequence of the evolution of the diesel engine to meet the increasingly stringent emissions regulations is that more effort to accommodate the associated changes is driven to the vehicle manufacturers.

The increasing severity in emission standards around the world has been accompanied by the development of more active, durable catalysts. With a view to investigating the effects of high thermal aging on the catalyst performance and structure, the relationships of washcoat composition, washcoat structure, and PGM location with respect to catalyst activity were clarified using a model gas test, as well as physical and chemical characterization methods. The influence of newly developed washcoat components and PGM location on catalyst performance are also demonstrated by engine bench tests. The results obtained in this study indicate the newly developed Pt/Rh catalyst techologies are appropriate for future applications in which the catalyst will be exposed to extremely high temperature and flowrates.

This paper presents a compact temperature control device to cool down hot exhaust gas coming out of an aftertreatment emission control system. Active DPF (Diesel Particulate Filter) regeneration is required for aftertreatment emission controls to meet the 2007 EPA (Environmental Protection Agency) PM(Particulate Matter) standard. However, regeneration of the DPF temporarily elevates temperatures in the filter to eliminate accumulated soot. This can increase the temperature of the exhaust gas. The temperature control device in this paper draws ambient air into the hot exhaust stream and mixes them together in such a fashion to maximize temperature drop and minimize back pressure for a limited space without any moving parts or supply of extra power. The simple and compact design of the device makes it a cost-effective candidate to retrofit to an existing aftertreatment system.

It has long been recognized that the key to achieving stringent emission standards such as ULEV is the control of cold-start hydrocarbons. This paper describes a new approach for achieving excellent cold-start hydrocarbon control. The most important component in the system is a catalyst that is highly active at ambient temperature for the exothermic CO oxidation reaction in an exhaust stream under net lean conditions. This catalyst has positive order kinetics with respect to CO for CO oxidation. Thus, as the concentration of CO in the exhaust is increased, the rate of this reaction is increased, resulting in a faster temperature rise over the catalyst.

The molecular filtration of sulfur components in ultra low sulfur diesel (ULSD) fuel is described. A comprehensive screening of potential sulfur removal chemistries has yielded a sorbent which has the capability to efficiently remove organo-sulfur components in ULSD fuel. This sorbent has been used to treat ULSD fuel on a heavy duty engine equipped with NOx adsorber after-treatment technology and has been shown to lengthen the time between desulfation steps for the NOx adsorber. The fuel properties, cetane number and aromatics content, etc., have not been changed by the removal of the sulfur in the fuel with the exception of the lubricity which is reduced.

The implementations of the Tier 2 and LEVII emission levels require fast catalyst light-off and fast closed loop control through high-speed engine management. The paper describes the development of innovative catalyst designs. During the development thermal and mechanical boundary conditions were collected and component tests conducted on test rigs to identify the emission and durability performance. The products were evaluated on a Super Imposed Test Setup (SIT) where thermal and mechanical loads are applied to the test piece simultanously and results are compared to accelerated vehicle power train endurance runs. The newly developed light-off catalyst with Perforated Foil Technology (PE) showed superior emission light-off characteristic and robustness.

Model-based control strategies are important for meeting the dual objective of maximizing NOx reduction and minimizing NH3 slip in urea-SCR catalysts. To be implementable on the vehicle, the models should capture the essential behavior of the system, while not being computationally intensive. This paper discusses the adequacy of two different reduced order SCR catalyst models and compares their performance with a higher order model. The higher order model assumes that the catalyst has both diffusion and reaction kinetics, whereas the reduced order models contain only reaction kinetics. After describing each model, its parameter identification and model validation based on experiments on a Navistar I6 7.6L engine are presented. The adequacy of reduced order models is demonstrated by comparing the NO, NO2 and NH3 concentrations predicted by the models to their concentrations from the test data.

The SNR-technique is a new NOx aftertreatment system for lean burn gasoline and diesel applications. The objective of SNR is NOx removal from lean exhaust gas by NOx adsorption and subsequent selective external recirculation and decomposition of NOx in the combustion process. The SNR-project is composed of two major parts. Firstly the development of NOx adsorbents which are able to store large quantities of NOx in lean exhaust gas, and secondly the NOx decomposition by the combustion process. Emphasis of this paper is the investigation of NOx reduction in the combustion process, including experimental investigation and numerical simulation. The NOx decomposition process has been proven in diesel and lean-burn gasoline engines. Depending on the type of engine NOx-conversion rates up to 90 % have been observed. Regarding the complete SNR-system, including the efficiency of the adsorbing material and the NOx decomposition by the combustion, a NOx removal of more than 50% is achievable.

Selective NOx recirculation (SNR), involving adsorption, selective external recirculation and decomposition of the NOx by the combustion process, is itself a promising technique to abate NOx emissions. Three types of materials containing Ba: barium aluminate, barium tin perovskite and barium Y-zeolites have been developed to adsorb NOx under lean-burn or Diesel conditions, with or without the presence of S02. All these materials adsorb NO2 selectively (lean-burn conditions), and store it as nitrate/nitrite species. The desorption takes place by decomposition of these species at higher temperatures. Nitrate formation implies also sulfate formation in the presence of SO2 and SO3, while the NO2/SO2 competition governs the poisoning of such catalysts.

The objective of this effort was to develop an understanding of how different converter substrate cell structures impact tailpipe emissions and pressure drop from a total systems perspective. The cell structures studied were the following: The catalyst technologies utilized were a new technology palladium only catalyst in combination with a palladium/rhodium catalyst. A 4.0-liter, 1997 Jeep Cherokee with a modified calibration was chosen as the test platform for performing the FTP test. The experimental design focused on quantifying emissions performance as a function of converter volume for the different cell structures. The results from this study demonstrate that the 93 square cell/cm2 structure has superior performance versus the 62 square cell/cm2 structure and the 46 triangle cell/cm2 structure when the converter volumes were relatively small. However, as converter volume increases the emissions differences diminish.

The performance characteristics of a commercial lean-NOX trap catalyst were evaluated between 200 and 500°C, using H2, CO, and a mixture of both H2 and CO as reductants before and after different high-temperature aging steps, from 600 to 750°C. Tests included NOX reduction efficiency during cycling, NOX storage capacity (NSC), oxygen storage capacity (OSC), and water-gas-shift (WGS) and NO oxidation reaction extents. The WGS reaction extent at 200 and 300°C was negatively affected by thermal degradation, but at 400 and 500°C no significant change was observed. Changes in the extent of NO oxidation did not show a consistent trend as a function of thermal degradation. The total NSC was tested at 200, 350 and 500°C. Little change was observed at 500°C with thermal degradation but a steady decrease was observed at 350°C as the thermal degradation temperature was increased.

The successful development of new products is contingent on clearly understanding product requirements and defining appropriate design activities to deliver the right product. Even if one can clearly understand the abstract requirements implied by the voice-of-customer (VOC), engineers still work best to a set of specifications that define the product in objective measures. The task of extracting the systems specifications from text versions of product requirements is not trivial. Full order dynamic models of mass, springs and dampers provide understanding of vehicle performance; however, the engineer has to define the dynamic characteristics based on his understanding of requirements and translate them into technical specifications. The result can be too dependent on human assumptions and judgments at this point. This work was done to understand how to apply Object Oriented Design (OOD) methodology to trace requirements of a mechanical system to design parameters.

Future US emissions limits are likely to mean a sophisticated nitrogen oxide (NOx) reduction technique is required for all vehicles with a diesel engine, which is likely to be either NOx trap or selective catalytic reduction (SCR) technology. To investigate the potential of SCR for NOx reduction on a light duty vehicle, a current model vehicle (EUII M1 calibration), of inertia weight 1810 kg, was equipped with an urea-based SCR injection system and non-vanadium, non-zeolitic SCR catalysts. To deal with carbon monoxide (CO), hydrocarbon (HC) and volatile organic fraction (VOF), a diesel oxidation catalyst was also incorporated into the system for most tests. Investigations into the effect of placing the oxidation catalyst at different positions in the system, changing the volume of the SCR catalysts, increasing system temperature through road load changes, varying the SCR catalyst composition, and changing the urea injection calibration are discussed.

The Fischer-Tropsch (FT) process can be used to synthesize diesel fuels from a variety of energy sources, including coal, natural gas and biomass. Diesel fuels produced from the FT process are essentially sulfur-free, have very low aromatic content, and have excellent ignition characteristics. Because of these favorable attributes, FT diesel fuels may offer environmental benefits over transportation fuels derived from crude oil. Previous tests have shown that FT diesel fuel can be used in unmodified engines and have been shown to lower regulated emissions. Whereas exhaust emissions reductions from these previous studies have been impressive, this paper demonstrates that far greater exhaust emissions reductions are possible if the diesel engine is optimized to exploit the properties of the FT fuels. A Power Stroke 7.3 liter turbocharged diesel engine has been modified for use with FT diesel.

The structural design of current vehicle front units has to account for an increasing number of constraints: improvement of real-world performance in safety for occupants and others road users, perform in the various ratings and meet future regulations. Therefore the structural car design is the result of a compromise between pedestrian protection, car-to-car compatibility and self- protection. In addition to these safety considerations, reparability constraints are becoming more and more demanding and intrusive toward the other safety requirements. The need to reduce emissions through fuel consumption control requires a reduction of the overall body weight which leads usually to more difficulties to achieve a correct structural behavior. Some of these constraints lead to solutions which are in opposition and in general to unsatisfactory compromises. It is suggested to develop a more comprehensive approach in order to better take into account both safety requirements and reparability.

This oil category was driven by two new cooled exhaust gas recirculation (EGR) engine tests operating with 15% EGR, with used oil soot levels at the end of the test ranging from 6 to 9%. These tests are the Mack T-10 and Cummins M11 EGR, which address ring, cylinder liner, bearing, and valve train wear; filter plugging, and sludge. In addition to these two new EGR tests, there is a Caterpillar single-cylinder test without EGR which measures piston deposits and oil consumption control using an articulated piston. This test is called the Caterpillar 1R and is included in the existing Global DHD-1 specification. In total, the API CI-4 category includes eight fired-engine tests and seven bench tests covering all the engine oil parameters. The new bench tests include a seal compatibility test for fresh oils and a low temperature pumpability test for used oils containing 5% soot. This paper provides a review of the all the tests, matrix results, and limits for this new oil category.

This paper describes the development of new high performance three-way catalyst (TWC) formulations with improved activity and enhanced thermal stability. These new TWC formulations enable the converter to be fitted closer to the engine and allow this future legislation to be met with catalysts using PGM levels significantly lower than those currently being employed. The performance benefits of these advanced platinum- and palladium-based catalysts are demonstrated on a number of different vehicles after bench-engine ageing.

The influence of catalyst volume, cell density and precious metal loading on the catalyst efficiency were investigated to design a low cost catalyst system. In a first experiment the specific loading was kept constant for a 500cpsi and a 900cpsi substrate. In a second experiment the palladium loading was reduced on the 900cpsi substrate and the same PM loading was applied to a 1200cpsi substrate with lower volume. Finally the loading was further reduced for the 1200cpsi substrate. The following parameters were studied after aging: Catalyst performance of standard cell density compared to high cell density technology Light-off performance and catalyst efficiency as a function of Palladium loading and substrate cell density Catalyst efficiency as a function of AFR biasing The performance of the aged catalysts was investigated in a lambda sweep test and in light-off tests at an engine bench.