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The regulations for mobile applications will become stricter in Euro 6 and further emission levels and require the use of active aftertreatment methods for NOX and particulate matter. SCR and LNT have been both used commercially for mobile NOX removal. An alternative system is based on the combination of these two technologies. Developments of catalysts and whole systems as well as final vehicle demonstrations are discussed in this study. The small and full-size catalyst development experiments resulted in PtRh/LNT with optimized noble metal loadings and Cu-SCR catalyst having a high durability and ammonia adsorption capacity. For this study, an aftertreatment system consisting of LNT plus exhaust bypass, passive SCR and engine independent reductant supply by on-board exhaust fuel reforming was developed and investigated. The concept definition considers NOX conversion, CO2 drawback and system complexity.

An important trend among vehicle NVH engineers is the production of attractive engine acceleration sound quality for the enhancement of a vehicle's image and performance. In addition, customers have increasing interest and enjoyment in customizing their cars to reflect their personal taste and preferences. The PESS (Personalized Engine Sound System) has been developed for making a unique and individually customizable vehicle concept. The system allows the customers an opportunity to create a variety of engine sounds in a single vehicle using active sound design technology. In this system, three different engine sound concepts are pre-defined, Dynamic, Sporty, and Extreme. Each of the engine sounds can then be adjusted with parameters that determine the timbre, such as main order, rumble, and high order. In addition, the pedal position during acceleration has also been used as a parameter to further personalize the experience.

A combined experimental and computational study of 3-D unsteady compressible flow in exhaust manifold and CCC system was performed to understand the flow characteristics and to improve the flow distribution of pulsating exhaust gases within monolith. An experimental study was carried out to measure the velocity distribution in production exhaust manifold and CCC under engine operating conditions using LDV (Laser Doppler Velocimetry) system. Velocity characteristics were measured at planes 25 mm away from the front surface of first monolith and between two monolithic bricks. To provide boundary conditions for the computational study, velocity fields according to crank angle were also measured at the entrance of exhaust manifold. The comparisons of exhaust gas flow patterns in the junction and mixing pipe between experimental and computational results were made.

As the current and future emission regulations become stringent, the research on exhaust manifold with CCC (Close Coupled Catalyst) has been the interesting and remarkable subject. To design of exhaust manifold with CCC is a difficult task due to the complexity of the flow distribution caused by the pulsating flows that are emitted at the exhaust ports. This study is concerned with the theoretical and experimental approach to improve catalyst flow uniformity through the basic understanding of exhaust flow characteristics. Computational and experimental approach to the flow for exhaust manifold of conventional cast type, stainless steel bending type with 900 cell CCC system in a 4-cylinder gasoline engine was performed to investigate the flow distribution of exhaust gases.

Several different possibilities will be described and discussed on the processes of reducing NOx in lean-burn gasoline and diesel engines. In-company studies were conducted on zeolitic catalysts. With lean-burn spark-ignition engines, hydrocarbons in the exhaust gas act as a reducing agent. In stationary conditions at λ = 1.2, NOx conversion rates of approx. 45 % were achieved. With diesel engines, the only promising variant is SCR technology using urea as a reducing agent. The remaining problems are still the low space velocity and the narrow temperature window of the catalyst. The production of reaction products and secondary reactions of urea with other components in the diesel exhaust gas are still unclarified.

This paper presents a complete methodology for performing finite-volume-based detached-eddy simulation for the prediction of aerodynamic forces and detailed flow structures of passenger vehicles developed using the open-source CFD toolbox OpenFOAM®. The main components of the methodology consist of an automatic mesh generator, a setup and initialisation utility, a DES flow solver and analysis and post-processing routines. Validation of the predictions is done on the basis of detailed comparisons to experimental wind-tunnel data. Results for lift and drag are found to compare favourably to the experiments, with some moderate discrepancies in predicted rear lift. Point surface-pressure measurements, oil-streak images and maps of total pressure in the flow field demonstrate the approach's capabilities to predict the fine detail of complex flow regimes found in automotive aerodynamics.

The need to reduce weight of large and heavy components used by the automotive and aerospace industries such as engine block, cylinder head cover and helicopter gearbox housing has led to the development of new Mg gravity casting alloys that provide adequate properties and cost effective solution. The new Mg gravity casting alloys are designed for high stressed components that operate at a temperature up to 300°C. These new alloys exhibit excellent mechanical properties and creep resistance in T-6 conditions. The present paper aims at introducing three new Mg gravity casting alloys designated MRI 201S, MRI 202S and MRI 203S, which were recently developed by the Magnesium Research Institute of DSM and VW. Apart from the excellent high temperature performance of these alloys, they provide adequate castability and dimension stability along with good weldability and corrosion resistance.

The California LEV1 II program will be introduced in the year 2003 and requires a further reduction of the exhaust emissions of passenger cars. The cold start emissions represent the main part of the total emissions of the FTP2-Cycle. Cold start emissions can be efficiently reduced by injecting secondary air (SA) in the exhaust port making compliance with the most stringent standards possible. The thermochemical conditions (mixing rate and temperature of secondary air and exhaust gas, exhaust gas composition, etc) prevailing in the exhaust system are described in this paper. This provides knowledge of the conditions for auto ignition of the mixture within the exhaust manifold. The thus established exothermal reaction (exhaust gas post-combustion) results in a shorter time to light-off temperature of the catalyst. The mechanisms of this combustion are studied at different engine idle conditions.

For substantial reduction of fuel consumption of their vehicle fleet, Volkswagen AG has decided to develop spark-ignition engines with direct fuel injection. To launch this new engine concept with stratified lean operation mode while at the same time meeting the stringent EU IV emission standards, it was necessary to develop a suitable exhaust gas aftertreatment system. This was achieved as part of an intensive co-operation between Volkswagen AG and OMG, formerly dmc2 Degussa Metals Catalysts Cerdec AG. The paper describes the demands for exhaust gas aftertreatment due to lean burn operation. In addition the main development steps of the exhaust gas aftertreatment system for Volkswagen FSI engines and catalyst durability over vehicle lifetime are discussed. Focus is laid on the catalyst system design and coating variations. Volkswagen developed a new closed-loop emission control management system which uses NOx-sensor signals for the first time worldwide.

Conventional EPS (Electric Power Steering) systems are operated by one type of steering tuning map set by steering test drivers before being released to customers. That is, the steering efforts can't change in many different driving conditions such as road conditions (low mu, high mu and unpaved roads) or some specific driving conditions (sudden stopping, entering into EPS failure modes and full accelerating). Those conditions can't give drivers consistent steering efforts. This paper approached the new concept technology detecting those conditions by using vehicle and EPS sensors such as tire wheel speeds, vehicle speed, steering angle, steering torque, steering speed and so on. After detecting those conditions and judging what the best steering efforts for safe vehicle driving are, EPS systems automatically can be changed with the steering friction level and selection of steering optimized mapping on several conditions.

Meeting current exhaust emission standards requires rapid catalyst light-off. Closed-coupled catalysts are commonly used to reduce light-off time by minimizing exhaust heat loss between the engine and catalyst. However, this exhaust gas system design leads to a coupling of catalyst heating and engine operation. An engine-independent exhaust gas aftertreatment can be realized by combining a burner heated catalyst system (BHC) with an underfloor catalyst located far away from the engine. This paper describes some basic characteristics of such a BHC system and the results of fitting this system into a Volkswagen Touareg where a single catalyst was located about 1.8 m downstream of the engine. Nevertheless, it was possible to reach about 50% of the current European emission standard EU 4 without additional fuel consumption caused by the BHC system.

The EPEFE study (European Programme on Emissions, Fuels and Engine Technologies), /1/ and other programmes have identified an increase in tailpipe NOx emissions with reduced gasoline aromatics content for modern 3-way controlled catalyst vehicles. This effect occurs with fully warmed-up catalyst under closed-loop operation. In order to understand the reasons for this effect VW and Shell have mechanistically investigated the effects of fuel properties on EMS (engine management system) and catalyst performance. Fuels with independent variation of oxygen, aromatics and mid-range volatility were tested in different VW engines. λ was monitored using sensors located both pre and post catalyst. The results confirmed that reducing gasoline aromatics content reduced engine-out emissions but increased tailpipe NOx emissions. It could be shown that differences in H/C ratio led to differences in the hydrogen content of engine-out emissions which affected the reading of the λ sensor.

High specific power, additional hardware and mapping optimization was done to achieve reduction of fuel economy for current engine in this study. 2 stage turbocharger with serial configuration was best candidate not only for high specific power at high engine speed but also for increase of low end torque for current engine. This increase of low end torque is important for development of transient characteristic of vehicle. DoE and efficient EGR Cooler was applied for optimization of fuel economy. DoE was useful for optimization of fuel consumption affected by various fuel injection parameters. This DoE was also efficient for matching optimal fuel economy after change of engine hardware. Performance improvement of engine with 2 stage turbocharger VGT was evaluated and additional development of fuel economy was performed in this study.

We developed new single coated Pd/Rh three-way catalysts (TWC). Several Pd/Rh single layered catalysts were prepared by changing the precious metal (PM) fixation method and adding new base metal oxides (BMO). These samples were compared with double-coated catalyst by using model gas activity test, BET test, XRD test and vehicle emission test. It is found that the performance of the single coated catalyst is as good as that of commercialized double-coated catalyst. The oxygen storage capacity of the single coated catalyst is better than that of double-coated catalyst. Moreover, manufacturing the single coated catalyst enables us to eliminate the unnecessary coating process which is essential to the conventional one. Our test results demonstrate that the developed catalyst has sufficient activity and durability of OSC to meet emission and OBD-II regulations.

An overview is given on the state of the art of a new catalytic exhaust gas aftertreatment device for diesel engines. The function of a precious metal based, flow-through type diesel oxidation catalyst is explained. Much attention is paid to the durability of the diesel oxidation catalyst and especially to the influence of poisoning elements on the catalytic activity. Detailed data on the interaction of poisoning elements such as sulfur, zinc and phosphorus with the catalytic active sites are given. Finally it is demonstrated that it is possible to meet the stringent emission standards for diesel passenger cars in Europe with a new catalyst generation over 80.000 km AMA aging.

Strategic Materials at Reaction Temperatures (SMART) is an approach used to design washcoat systems for passive 4-way emission control catalysts. Light duty diesel vehicles need to meet the European Motor Vehicle Emissions Group (MVEG) cycle or U. S. Federal test procedure (FTP 75). Emissions that are monitored include hydrocarbon (HC), nitrogen oxides (NOx), carbon monoxide (CO) and total particulate matter (TPM). Low engine-exhaust temperatures (< 200°C during city driving) and high temperatures (> 500-800°C under full load and wide-open throttle) make emission control a formidable task for the catalyst designer Gas phase HC, CO and NOx reactions must be balanced with the removal of the soluble organic fraction for the vehicle to be in compliance with regulations. The SMART approach uses model gases under typical operating conditions in the laboratory to better understand the function of individual washcoat components.

In a joint research project between industrial companies and a number of research institutes, nitrogen oxide conversion in oxygen containing exhaust gas has been investigated according to the following procedure Basic investigations of elementary steps of the chemical reaction Production and prescreening of different catalytic material on laboratory scale Application oriented screening of industrial catalyst material Catalyst testing on a lean bum gasoline engine, passenger car diesel engines (swirl chamber and DI) and on a DI truck engine Although a number of solid body structures show nitrogen oxide reduction by hydrocarbons, only noble metal containing catalysts and transition metal exchanged zeolites gave catalytic efficiencies of industrial relevance. A maximum of 25 % NOx reduction was found in the European driving cycle for passenger cars, about 40 % for truck engines in the respective European test.

Laser-induced exciplex fluorescence has been applied to the mixture formation process in the combustion chamber of an optically-accessible four-cylinder in-line spark-ignition engine in order to distinguish between liquid and vapor fuel distribution during the intake and compression stroke for different injection timings. The naphthalene/N,N,N′N′-tetramethyl p-phenylene diamine (TMPD) exciplex system excited at 308nm with a broadband XeCl excimer laser is used to obtain spectrally-separated, single-shot fluorescence images of the liquid or vapor phase of the fuel. For different timings of the fuel injector this technique is applied to obtain crank-angle-resolved images of the resulting mixture in the combustion chamber. The fluorescence light is detected with an intensified slow-scan CCD-camera equipped with appropriate filters.

In direct-injection gasoline (GDI) engines with charge stratification, minimizing engine-out nitrogen oxide (NOx) emission is crucial since exhaust-gas aftertreatment tolerates only limited amounts of NOx. Reduced NOx production directly lowers the frequency of energy-inefficient catalyst regeneration cycles. In this paper we investigate NO formation in a realistic GDI engine. Quantitative in-cylinder measurements of NO concentrations are carried out via laser-induced fluorescence imaging with excitation of NO (A-X(0,2) band at 248 nm), and subsequent fluorescence detection at 220-240 nm. Engine modifications were kept to a minimum in order to provide results that are representative of practical operating conditions. Optical access via a sapphire ring enabled identical engine geometry as a production line engine. The engine is operated with commercial gasoline (“Super-Plus”, RON 98).

A uniform flow distribution at converter inlet is one of the fundamental requirements to meet high catalytic efficiency. Commonly used tools for optimization of the inlet flow distribution are flow measurements as well as CFD analysis. This paper puts emphasis on the experimental procedures and results. The interaction of flow measurements and CFD is outlined. The exhaust gas flow is transient, compressible and hot, making in-situ flow measurements very complex. On the other hand, to utilize the advantages of flow testing at steady-state and cold conditions the significance of these results has to be verified first. CFD analysis under different boundary conditions prove that - in a first approach - the flow situation can be regarded as a sequence of successive, steady-state situations. Using the Reynolds analogy a formula for the steady-state, cold test mass flow is derived, taking into account the cylinder displacement and the rated speed.