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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.

An experiment was performed with a 1.3L catalytic converter design containing a front and rear catalyst each having a volume of 0.65 liters. This investigation varied the front catalyst parameters to study the effects of 1) substrate diameter, 2) substrate cell density, 3) Pd loading and 4) Rh loading on the FTP emissions on three different vehicles. Engine displacement varied from 2.4L to 4.7L. Eight different converters were built defined by a Taguchi L-8 array. Cold flow converter restriction results show the tradeoff in converter restriction between substrate cell density and substrate diameter. Vehicle FTP emissions show how the three vehicles are sensitive to the four parameters investigated. Platinum Group Metals (PGM) prices and Federal Test Procedure (FTP) emissions were used to define the emission value between the substrate properties of diameter and cell density to palladium (Pd) and rhodium (Rh) concentrations.

Vehicle exhaust flow is difficult to measure accurately and with high precision due to the highly transient nature of the cyclic events which are dependent on engine combustion parameters, varying exhaust gas compositions, pulsation effects, temperature and pressure. Bag mini-diluter (BMD) is becoming one of the few technologies chosen for SULEV and PZEV exhaust emission measurement and certification. A central part of the BMD system is an accurate and reliable exhaust flow measurement which is essential for proportional bag fill. A new device has been developed to accurately and reliably calibrate exhaust flow measurement equipments such as the E-Flow. The calibration device uses two different size laminar flow elements (LFE), a 40 CFM (1.13 m3/min) LFE for low end calibration and a 400 CFM (11.32 m3/min) LFE for higher flows. A blower is used to push flow through a main flow path, which then divides into two flow pathways, one for each of the two LFE's.

In order to match catalyst OBDII conditions the common procedure is oven aging with air, which is not suitable for complete converter systems due to mantle corrosion. The goal was, therefore, to find an alternative procedure to ensure a defined catalyst aging that would match 1,75 times the emission standard and is also good for SULEV. The new procedure currently being developed allows the aging of metal and ceramic catalysts as well as complete catalyst systems. The paper will present the aging process, emission data of fresh and aged catalysts and the feedback to the test car OBDII system.

Catalyst systems utilizing ceramic and metallic substrates were compared to assess the influence of various substrate parameters on the exhaust gas conversion efficiency and flow restriction. In particular, the substrate surface area, substrate specific heat capacity, and substrate volume were all evaluated for their importance in estimating the conversion efficiency of the catalyst system. Additionally, substrate open frontal area and cell hydraulic diameter were compared against exhaust restriction performance.

The future of diesel-engine-powered passenger cars and light-duty vehicles in the United States depends on their ability to meet Federal Tier 2 and California LEV2 tailpipe emission standards. The experimental purpose of this work was to examine the potential role of fuels; specifically, to determine the sensitivity of engine-out NOx and particulate matter (PM) to gross changes in fuel formulation. The fuels studied were a market-average California baseline fuel and three advanced low sulfur fuels (<2 ppm). The advanced fuels were a low-sulfur-highly-hydrocracked diesel (LSHC), a neat (100%) Fischer-Tropsch (FT100) and 15% DMM (dimethoxy methane) blended into LSHC (DMM15). The fuels were tested on modern, turbocharged, common-rail, direct-injection diesel engines at DaimlerChrysler, Ford and General Motors. The engines were tested at five speed/load conditions with injection timing set to minimize fuel consumption.

One of the key elements in efforts to minimize the noise emmissionis of engines and other machinery is the knowledge of the main noise radiating surfaces and the relation between measurable surface vibration and the sound pressure. Under the name of Airborne Source Quantification (ASQ), various techniques have been developed to discretize and quantify the source strength, and noise contributions, of vibrating surface patches of machinery or vehicle components. The noise contributions of patches to the sound pressure at specific locations in the sound field or to the total radiated sound power are identified. The source strength of equivalent point sources, the acoustic transfer from the source surface to critical sound field locations and finally the sound pressure contributions of the individual patches are quantified. These techniques are not unique to engine application, but very relevant for engine development. An example is shown for an engine under artificial excitation.

This paper describes the use of Vibro-Acoustics numerical modeling for prediction of an Air Intake System noise level for a commercial vehicle. The use of numerical methods to predict vehicle interior noise levels as well as sound radiated from components is gaining acceptance in the automotive industry [1]. The products of most industries can benefit from improved acoustic design. On the other hand, sound emission regulation has become more and more rigorous and customers expect quieter products. The aim of this work it is to assess the Vibro-Acoustics behavior of Air Intake System and influence of it in the sound pressure level of the vehicle.

Two active boom noise damping techniques using a Helmholtz resonator-based compensator and a lead compensator called a positive pressure feedback have been developed at the University of Dayton [1]. The two damping techniques are of feedback type and their compensators can be implemented in software or hardware (using inexpensive operational amplifiers). The active damping system would rely on a speaker, a low-cost microphone, two accelerometers, and an electronic circuit (or a micro-controller) to add damping to the offending low-frequency vibroacoustic modes of the cavity. The simplicity of the active boom noise damping system lends itself to be incorporated into a vehicle's sound system. The Helmholtz resonator-based strategy is implemented on a Dodge Durango sport utility vehicle. The control scheme adds appreciable amount of damping to the first cavity mode and the first structurally induced acoustic mode of the cabin.

The development of diesel powered passenger cars is driven by the enhanced emission legislation. To fulfill the future emission limits there is a need for advanced aftertreatment devices. A comprehensive study was carried out focusing on the improvement of the DOC as one part of these systems, concerning high HC/CO conversion rates, low temperature light-off behaviour and high temperature aging stability, respectively. The first part of this study was published in [1]. Further evaluations using a high temperature DPF aging were carried out for the introduced systems. Again the substrate geometry and the catalytic coating were varied. The results from engine as well as vehicle tests show advantages in a highly systematic context by changing either geometrical or chemical factors. These results enable further improvement for the design of the exhaust system to pass the demanding emission legislation for high performance diesel powered passenger cars.

Measuring vehicle exhaust volumetric flow rate accurately and precisely is critical in calculating the correct vehicle modal and bag mini-diluter exhaust emission constituent masses. It is also instrumental in engine calibration practices. Currently, DaimlerChrysler's Emission and Certification Lab in Auburn Hills, Michigan utilizes constant volume sampling bag systems to certify vehicles but the automotive technological trend is heading toward the bag mini-diluter for greater precision at low emission levels. The bag mini-diluters, as well as the modal sampling system, used extensively in vehicle development testing, rely on exhaust flow rate measurement by means of a direct vehicle exhaust flow meter named E-Flow. The E-Flow has few limitations such as flow profile instability at low idle flow rates and reaction to resonating pressure waves in the exhaust system.

A Robust Engineering experiment was performed to determine the effects PGM loading and placement on the FTP emissions of a 4 cylinder 2.4L and two 8 cylinder 4.7L vehicles. 1.3L catalytic converters were used containing a front and rear catalyst of equal volume. The experiment is defined by a Taguchi L-8 array. Eight different combinations of catalyst PGM loadings were aged and evaluated. Results show that nmHC and NOx emissions are predominately affected by the PGM loading of the front catalyst. The rear catalyst is insensitive to either Pt or Pd which can be used at low concentrations. Results also compare the benefits of Pd and Rh to reduce emissions. Confirmation runs suggest that significant reductions in PGM cost can be achieved over baseline designs.

A new family of automotive three-way conversion (TWC) catalyst technologies has been developed using a Precision Metal Addition (PMA) process. Precious metal (PGM) fixation onto the support occurs during the PMA step when the PGM is added to the slurry immediately prior to application to the monolith substrate. PMA slurries can be prepared with high precision and the slurry manufacturing process is greatly simplified. Further, it has been found that with the use of new generation washcoat (WC) materials, the same WC composition can be used for all three PGMs - Pt, Pd & Rh. Negative interactions between Pd and Rh in the same WC layer do not occur, providing advantages over older technologies. Thus, new WC compositions coupled with the PMA process offers precious metal flexibility. This FlexMetal family of catalyst technologies includes single layer Pd-only, Pd/Rh and Pt/Rh and dual layer bi-metal Pd/Rh and Pt/Rh and tri-metal Pt/Pd/Rh.

Future emission regulations and customer needs require revolutionary new approaches to engine management systems. In the EC part-funded AENEAS program the partners Ricardo, Kistler and DaimlerChrysler formed a consortium to investigate the application of a new combustion pressure sensor concept and innovative algorithms for engine management systems. This paper describes the general scope and the basic concepts of the system.

In a consortium of European industrial partners and research institutes, a combination of industrial development and scientific research was organised. The objective was to improve the catalytic NOx conversion for lean burn cars and heavy-duty trucks, taking into account boundary conditions for the fuel consumption. The project lasted for three years. During this period parallel research was conducted in research areas ranging from basic research based on a theoretical approach to full scale emission system development. NOx storage catalysts became a central part of the project. Catalysts were evaluated with respect to resistance towards sulphur poisoning. It was concluded that very low sulphur fuel is a necessity for efficient use of NOx trap technology. Additionally, attempts were made to develop methods for reactivating poisoned catalysts. Methods for short distance mixing were developed for the addition of reducing agent.