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A catalyst system, consisting of two different catalyst technologies within a single canister, was developed for MDV2 (Medium-Duty Vehicles, Class 2) to meet ULEV targets. The catalyst volume versus engine displacement is less than 50%. Three approaches taken: substrate study, PM loading study and new catalyst technology development are illustrated here. The most promising system features new catalyst technologies coated on high cell density substrates.

Diesel engines are far more efficient than gasoline engines of comparable size, and emit less greenhouse gases that have been implicated in global warming. In 2000, the US EPA proposed very stringent emissions standards to be introduced in 2007 along with low sulfur (< 15 ppm) diesel fuel. The California Air Resource Board (CARB) has also established the principle that future diesel fueled vehicles should meet the same low emissions standards as gasoline fueled vehicles and the EPA followed suit with its Tier II emissions regulation. Achieving such low emissions cannot be done through engine development and fuel reformulation alone, and requires application of NOx and particulate matter (PM) aftertreatment control devices. There is a widespread consensus that NOx adsorbers and particulate filter are required in order for diesel engines to meet the 2007 emissions regulations for NOx and PM. In this paper, the key exhaust characteristics from an advanced diesel engine are reviewed.

Volvo Car Corporation has developed a Reference Architecture for PAG1 Infotainment Systems. A Reference Architecture is an architecture scoping over more than a single system, i.e. an architecture aimed for a family of systems. The Infotainment Reference Architecture has since 2001 been successfully applied for the PAG family which so far covers the infotainment systems of Volvo XC90, Volvo S40/V50, Jaguar XK, Aston Martin DB9 and the brand new Volvo S80. In 1999, the system design departments started up with the clear objective to develop a system solution aiming for the PAG infotainment system family. The work was carried out according to the established development process at Volvo Cars. A year later a discouraging design review was performed. The number of involved functions, the level of function interaction and the distribution of functionalities between ECUs resulted in a non-manageable system solution.

The development and implementation of a new structure for data-driven models for NOX and soot emissions is described. The model structure is a linear regression model, where physically relevant input signals are used as regressors, and all the regression parameters are defined as grid-maps in the engine speed/injected fuel domain. The method of using grid-maps in the engine speed/injected fuel domain for all the regression parameters enables the models to be valid for changes in physical parameters that affect the emissions, without having to include these parameters as input signals to the models. This is possible for parameters that are dependent only on the engine speed and the amount of injected fuel. This means that models can handle changes for different parameters in the complete working range of the engine, without having to include all signals that actually effect the emissions into the models.

The aim of this paper is to investigate the potential of Lean NOx technology for diesel emission control. In this work, the focus is on the precious metal (low temperature) catalyst. Engelhard optimized the catalyst for cells per square inch (cpsi) and Platinum loading. Effect of various parameters, including, reductant type, catalyst volume, space velocity range and injector locations were investigated both analytically and experimentally at Cummins in search for the optimum system design. Both steady state and transient tests were conducted in this work. The precious metal catalysts have a narrow temperature window, however, with the use of proper reductant and an efficient control strategy (to minimize fuel penalty) cycle conversion efficiencies as high as 40% may be obtained for FTP-75. The analysis tool developed to aid the system design is capable of predicting effects of catalyst temperature, NOx concentration, O2 concentration, space velocity etc. on NOx conversion efficiency.

Catalytic control of motorcycle vehicle emissions requires that the catalytic element be carefully integrated into the exhaust system. The catalyst element physical parameters are optimized to achieve specific exhaust tuning requirements. Since the converter is located inside the muffler, the peak temperatures can severely stress both the catalytic active washcoat materials and the currently used metal monolith structure under some operating conditions. This paper addresses the development of an alternative ceramic monolithic catalyst that can be used for 2 and 4-stroke motorcycle applications. A new mounting technique was developed to contain the ceramic catalytic unit within a holder or converter shell with sufficient strength and durability to withstand the severe environment of 2-stroke engine exhaust.

Recently, catalyzed soot filters (CSF) for passenger vehicles have been introduced into the marketplace to comply with the European environmental requirements and future emission standards. The initial system consisted of one or two diesel oxidation catalysts (DOC) to meet the regulated HC and CO standards along with an under floor CSF to treat the particulate emissions. In order to meet the cold start requirements and to reduce system costs with a CSF only unit, converters are placed closer to the engine to minimize heat losses and more of the DOC functionality is integrated into the filter substrate. This work describes the development of such DOC-integrated CSF systems. One major challenge in the design of such systems is to ensure that there is sufficient catalyst functionality within the wall-flow substrate while maintaining an acceptable exhaust gas backpressure across the filter.

Maintaining the current ratio between certified and the customer-observed fuel consumption even with future required levels poses a considerable challenge. Increasing the efficiency of the driveline enables certified fuel consumption down to a feasible level in the order of 80 g CO₂/km using fossil fuels. Mainly affecting off-cycle fuel consumption, energy amounts used to create good interior climate as well as energy-consuming options and features threaten to further increase. Progressing urbanization will lead to decreasing average vehicle speeds and driving distances. Highly efficient powertrains come with decreased amounts of waste energy traditionally used for interior climate conditioning, thus making necessary a change of auxiliary systems.

A recently completed program was developed to evaluate ultra-low sulfur diesel fuels and passive diesel particle filters (DPF) in several different truck and bus fleets operating in Southern California. The primary test fuels, ECD and ECD-1, are produced by ARCO, a BP company, and have less than 15 ppm sulfur content. A test fleet comprised of heavy-duty trucks and buses were retrofitted with one of two types of catalyzed diesel particle filters, and operated for one year. As part of this program, a chemical characterization study was performed in the spring of 2001 to compare the exhaust emissions using the test fuels with and without aftertreatment. A detailed speciation of volatile organic hydrocarbons (VOC), polycyclic aromatic hydrocarbons (PAH), nitro-PAH, carbonyls, polychlorodibenzo-p-dioxins (PCDD) and polychlorodibenzo-p-furans (PCDF), inorganic ions, elements, PM10, and PM2.5 in diesel exhaust was performed for a select set of vehicles.

When developing gas exchange and combustion systems at Volvo Car Corporation, CFD (Computational Fluid Dynamics) is today a key tool. Three dimensional CFD is by tradition used to study one single component (e.g. manifolds and ports) at a time. Our experience is that this approach suffers from two main limitations; first that the boundary conditions (both upstream and downstream) are uncertain; and secondly that validation against experimental data is extremely difficult since any measured parameter will depend on the complete engine. Distribution of secondary gases and AFR (Air to Fuel ratio) are typical examples where traditional CFD methods fail. One proposed way to overcome these problems is to use 1D gas exchange models coupled with 3D CFD. The main problem with this approach is however the positioning and treatment of the boundaries between the models. Furthermore, the boundaries themselves will unconditionally cause disturbances in the pressure fields.

H2S emissions from a three-way catalyst are suppressed by incorporating copper or manganese oxide into a section downstream of the three-way catalyst.

Automotive turbo compressors generate high frequency noise in the air intake system. This sound generation is of importance for the perceived sound quality of luxury cars and may need to be controlled by the use of silencers. The silencers usually contain resonators with slits, perforates and cavities. The purpose of the present work is to develop acoustic models for these resonators where relevant effects such as the effect of a realistic mean flow on losses and 3D effects are considered. An experimental campaign has been performed where the two-port matrices and transmission loss of sample resonators have been measured without flow and for two different mean flow speeds. Models for two resonators have been developed using 1D linear acoustic theory and a FEM code (COMSOL Multi-physics). For some resonators a separate linear 1D Matlab code has also been developed.

Most OEMs are shifting their strategy and way of thinking regarding ECUs. This, in combination with the electrification of vehicles and the shift towards software-based companies (car as a device), implies one of the biggest paradigm changes in automotive history. On the other hand, despite the current struggles, remarkable advances have been made in electronic technology during the past few years. These developments have opened a door to very promising enabling technology, with exterior lighting as a main target market. These circumstances seem to have created a perfect storm leading to new strategies for electronic control and driving for (front and rear) exterior lighting. We, at our company, have investigated the enabling technology, challenges, and benefits of this emerging exterior lighting approach, that we call ‘ECU-Less’.

In the effort to design reliable diesel engines which meet the strict US Federal Regulations for emissions, considerable progress has been made by engine manufacturers. Particulate emissions are now below 0.25 g/BHPh and after 1994 will be below 0.1 g/BHPh. Diesel fuel has a revised specification limit of 0.05% sulfur as a means to assist diesel engine manufacturers in complying with the 1994 standard. Diesel oxidation catalysts (DOC) have been chosen as another means. A DOC can efficiently oxidize soluble organic particulate matter (SOF) and gaseous hydrocarbons while easily oxidizing SO2 to SO3-the latter being a particulate and undesirable. Selective DOCs have been developed which maintain the activity for SOF and minimize the undesirable SO2 oxidation step. However, performance for gaseous hydrocarbons may be negatively affected.

The emission capability of an exhaust system tuned for improved engine performance from an in-line four-cylinder engine has been investigated. The exhaust system comprises two close-coupled catalysts; each located in separate exhaust streams and has been termed the 4-2 close-coupled catalysts (CCC) -1 system. It has been shown that, given equivalent total catalyst volume, this system configuration results in compromised high exhaust flow rate emissions performance compared with a single catalyst (4-1semi-CCC) system. This emissions performance deficit has been attributed to the effect of engine frequency flow pulsations, which result in relatively high peak space velocities in the 4-2CCC-1 system despite the mean space velocity being consistent. Engine-based AFR Bias Sweep tests suggest that hydrocarbon emissions are most strongly affected by this phenomenon. At lower exhaust flow rates, the difference in performance between the two systems is negligible.

The application of SCR deNOx aftertreatment was studied on two about 12 liter class heavy-duty diesel engines within a consortium project. Basically, the system consists of a dosage system for aqueous urea injection and a vanadia based SCR catalyst, without an upstream or downstream oxidation catalyst. The urea injection system for a DAF and a Renault V.I. (Véhicules Industriels) diesel engine was calibrated on the engine test bench taking into account dynamic effects of the catalyst. For both engine applications NOx reduction was 81% to 84% over the ESC and 72% over the ETC. CO emission increased up to 27%. PM emission is reduced by 4 to 23% and HC emission is reduced by more than 80%. These results are achieved with standard diesel fuel with about 350 ppm sulfur. The test engines and SCR deNOx systems were built into a DAF FT95 truck and a Renault V.I. Magnum truck.

Heat loss is one of the greatest energy losses in engines. More than half of the heat is lost to cooling media and exhaust losses, and they thus dominate the internal combustion engine energy balance. Complex processes affect heat loss to the cylinder walls, including gas motion, spray-wall interaction and turbulence levels. The aim of this work was to experimentally compare the heat transfer characteristics of a stepped-bowl piston geometry to a conventional re-entrant diesel bowl studied previously and here used as the baseline geometry. The stepped-bowl geometry features a low surface-to-volume ratio compared to the baseline bowl, which is considered beneficial for low heat losses. Speed, load, injection pressure, swirl level, EGR rate and air/fuel ratio (λ) were varied in a multi-cylinder light duty engine operated in conventional diesel combustion (CDC) mode.

Gasoline engine oils contain a variety of additives including phosphorous-based compounds, for maintaining their characteristics. During the life of the vehicle, oil is consumed via piston ring blowby or leakage from valve stem guides. Phosphorous compounds from the consumed oil end up being deposited on the three way conversion catalysts resulting in a degradation of the conversion efficiencies of all three pollutants, hydrocarbons, carbon monoxide and nitrogen oxides. To simulate this deterioration in performance, an accelerated aging cycle has been developed which replicates the effect of the interaction between the phosphorous species and the washcoat components. This paper describes the poison aging protocol and the effect of aging temperature, poison level and duration of aging. In this paper, we will we also discuss some of the catalyst deactivation mechanisms and methods to simulate them using dynamometer-mounted engines.

Two imaging techniques are used to investigate the interaction between developed combustion from earlier injections and partially oxidized fuel (POF) of a subsequent injection. The latter is visualized by using planar laser induced fluorescence (PLIF) of formaldehyde and poly-cyclic aromatic hydrocarbons. High speed imaging captures the natural luminescence (NL) of the prevailing combustion. Three different fuel injection strategies are studied. One strategy consists of two pilot injections, with modest separations after each, followed by single main and post injections. Both of the other two strategies have three pilots followed by single main and post injections. The separations after the second and third pilots are several times shorter than in the reference case (making them closely-coupled). The closely-coupled cases have more linear heat release rates (HRR) which lead to much lower combustion noise levels.

This paper describes the experimental study of a tumble-flap mounted in the intake port of a single-cylinder spark-ignited gasoline engine. The research question addressed was whether an optimal tumble level could be found for the combustion system under investigation. Indicated fuel consumption was measured for a number of part-load operating points with the tumble-flap either open or closed. The experimental results were subjected to an energy balance analysis to understand which portion of the fuel energy was converted to work and how much was lost by incomplete combustion, heat losses to walls and to the exhaust gases, as well as to pumping losses. Closing the tumble-flap resulted in reduced fuel consumption only in a small area of the operating map: only at low-speed, low-load operation, a benefit could be obtained.