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The results of previous Life Cycle Assessments indicate the ecological dominance of the vehicle's use phase compared to its production and recycling phase. Particularly the so-called weight-induced fuel saving coefficients point out the great spectrum (0.15 to 1.0 l/(100 kg · 100 km)) that affects the total result of the LCA significantly. The objective of this article, therefore, is to derive a physical based, i.e. scientific chargeable and practical approved, concept to determine the significant parameters of a vehicle's use phase for the Life Cycle Inventory. It turns out that - besides the aerodynamic and rolling resistance parameters and the efficiencies of the power train - the vehicle's weight, the rear axle's transmission ratio and the driven velocity profile have an important influence on a vehicle's fuel consumption.

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.

An investigation was conducted to elucidate, how the latest turbocharged, direct injection Volkswagen diesel engine generation with cylinder pressure based closed loop control, to be launched in the US in 2008, reacts to fuel variability. A de-correlated fuels matrix was designed to bracket the range of US market fuel properties, which allowed a clear correlation of individual fuel properties with engine response. The test program consisting of steady state operating points showed that cylinder pressure based closed loop control successfully levels out the influence of fuel ignition quality, showing the effectiveness of this new technology for markets with a wide range of fuel qualities. However, it also showed that within the cetane range tested (39 to 55), despite the constant combustion mid-point, cetane number still has an influence on particulate and gaseous emissions. Volatility and energy density also influence the engine's behavior, but less strongly.

Synthetic fuels are expected to play an important role for future mobility, because they can be introduced seamlessly alongside conventional fuels without the need for new infrastructure. Thus, understanding the interaction of GTL fuels with modern engines, and aftertreatment systems, is important. The current study investigates potential benefits of GTL fuel in respect of diesel particulate filters (DPF). Experiments were conducted on a Euro 4 TDI engine, comparing the DPF response to two different fuels, normal diesel and GTL fuel. The investigation focused on the accumulation and regeneration behavior of the DPF. Results indicated that GTL fuel reduced particulate formation to such an extent that the regeneration cycle was significantly elongated, by ∼70% compared with conventional diesel. Thus, the engine could operate for this increased time before the DPF reached maximum load and regeneration was needed.

Internal combustion engines with lean homogeneous charge and auto-ignition combustion of gasoline fuels have the capability to significantly reduce fuel consumption and realize ultra-low engine-out NOx emissions. Group research of Volkswagen AG has therefore defined the Gasoline Compression Ignition combustion (GCI®) concept. A detailed investigation of this novel combustion process has been carried out on test bench engines and test vehicles by group research of Volkswagen AG and IAV GmbH Gifhorn. Experimental results confirm the theoretically expected potential for improved efficiency and emissions behavior. Volkswagen AG and IAV GmbH will utilize a highly flexible externally supercharged variable valve train (VVT) engine for future investigations to extend the understanding of gas exchange and EGR strategy as well as the boost demands of gasoline auto-ignition combustion processes.

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.

BMW, DaimlerChrysler, Motorola and Philips present their joint development activity related to the FlexRay communication system that is intended for distributed applications in vehicles. The designated applications for powertrain and chassis control place requirements in terms of availability, reliability and data bandwidth that cannot be met by any product currently available on the market under the testing conditions encountered in an automobile. A short look back on events so far is followed by a description of the protocol and its first implementation as an integrated circuit, as well as its incorporation into a complete tool environment.

Flow control by fluidic devices - without moving parts - offers advantages of reliability and low cost. As an example of their automobile application based on authors'' long-time experience the paper describes a fluidic valve for switching exhaust gas flow in a NOx absorber into a by-pass during regeneration phase. The unique feature here is the fluidic valve being of monostable and of axisymmetric design, integrated into the absorber body. After development in aerodynamic laboratory, the final design was tested on engine test stand and finally in a car. This proved that the performance under high temperature and pulsation existing in exhaust systems is reliable and promising. Fluidic valves require, however, close matching with aerodynamic load. To optimize the exhaust system layout for the whole load-speed range and reaching minimum counter- pressure, both the components of exhaust system and control strategy have to be properly adopted.

The automakers that comprise MOST® describe the reasons for this decision. First, they present the automobile industry's needs relative to multimedia networks in vehicles. Then, they present the different aspects of the MOST® technology. Multimedia networks are used in the electronics market, but they do not meet the technical and industrial constraints of the automobile electronics, which is why six automakers are working on most technology under the aegis of ""Most Cooperation.'' The transmission rate is a decisive aspect in the selection of a multimedia network. The rate of sound and video applications require fiber optics. The multimedia network rate must be adequate for a vehicle equipped with the maximum number of options, but the maximum rate is limited by the number of passengers.

The optimization of the vaporization and mixture formation process is of great importance for the development of modern gasoline direct injection (GDI) engines, because it influences the subsequent processes of the ignition, combustion and pollutant formation significantly. In consequence, the subject of this work was the development of a measurement technique based on the laser induced exciplex fluorescence (LIF), which allows the two dimensional visualization and quantification of the in-cylinder air/fuel ratio. A tracer concept consisting of benzene and triethylamine dissolved in a non-fluorescent base fuel has been used. The calibration of the equivalence ratio proportional LIF-signal was performed directly inside the engine, at a well known mixture composition, immediately before the direct injection measurements were started.

For the measurement of NO and NO2 the CLD-analyzer (chemiluminescense detector) has been used for more than twenty-five years. The disadvantage of the CLD is that NO can be measured only. To obtain total NOX (NO+NO2) the exhaust gas sample has to flow through a catalytic converter, which reduces NO2 to NO. The converter has a efficiency between 90 and 100%. For precise NO and NO2 values it is an advantage to analyze NO and NO2 directly. This paper describes a new UV NOX-analyzer for the simultaneous measurement of NO and NO2. Two different configurations, for high and low concentrations, eg. CVS-bag analysis are presented. The performance of the analyzers is documented in comparison to the UV-RAS analyzer with converter for NOX [1] and the conventional CLD-analyzer. The benefits of the new analyzer compared to analyzers equipped with a converter are given in detailed test results.

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.

More stringent emissions regulations, space limitations for catalytic converters in modern automotive applications, and new engine technologies constitute design challenges for today's engineers. In that context high cell density thinwall and ultrathinwall ceramic substrates have been designed into advanced catalytic converters. Whereas the majority of these substrates have a square cell geometry, a potential for further emissions improvement has been predicted for hexagonal cell structures. In order to verify these predictions, a ceramic substrate has been developed combining the features of high cell density, ultrathin cell walls, and hexagonal cell structure. Based on modeling data, the actual cell density and wall thickness of the hexagonal cell substrate will be defined. The performance of that substrate will be assessed by comparing experimental emissions results using two modern Volkswagen engines.

Flame Ionization Detectors (FID) can be used to detect organic hydrocarbons that occur in plastics, lacquers, adhesives, solvents and gasoline. These substances are ionized in the hydrogen flame of the FID. The ionization current that is produced depends on the amount of hydrocarbon in the sample. With the lowering of emissions limits, measuring instruments, including the FID, have to be able to detect very low values. For SULEV (Super-Ultra Low Emissions Vehicle) measurements the accuracy and also the general applicability of the CVS (Constant Volume Sampling) measuring technique are now questioned. Basic understanding is necessary to ask the right questions. One important issue is the science behind the measurement principle of the FID. And in this case especially the influence of contamination of the operating gases, cross sensitivity and data processing on the Limit of Detection (LOD).

A local Gaussian process regression approach is presented, which allows to model nonlinearities of internal combustion engines more accurate than global Gaussian process regression. By building smaller models, the prediction of local system behavior improves significantly. In order to predict a value, the algorithm chooses the nearest training points. The number of chosen training points depends on the intensity of estimated nonlinearity. After determining the training points, a model is built, the prediction performed and the model discarded. The approach is demonstrated with a benchmark system and air charge test bed measurements. The measurements are taken from a turbocharged SI gasoline engine with both variable inlet valve lift and variable inlet and exhaust valve opening angle. The results show how local Gaussian process regression outmatches global Gaussian process regression concerning model quality and nonlinearities in particular.

Air charge calibration of turbocharged SI gasoline engines with both variable inlet valve lift and variable inlet and exhaust valve opening angle has to be very accurate and needs a high number of measurements. In particular, the modeling of the transition area from unthrottled, inlet valve controlled resp. throttled mode to turbocharged mode, suffers from small number of measurements (e.g. when applying Design of Experiments (DoE)). This is due to the strong impact of residual gas respectively scavenging dominating locally in this area. In this article, a virtual residual gas sensor in order to enable black-box-modeling of the air charge is presented. The sensor is a multilayer perceptron artificial neural network. Amongst others, the physically calculated air mass is used as training data for the artificial neural network.

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.

Meeting the stringent efficiency demands of next generation direct injection engines requires not only optimization of the injection system and combustion chamber, but also an optimal in-cylinder swirling charge flow. This charge motion is largely determined by the shape of the intake port arm geometry and the valve position. In this paper, we outline an extensible methodology implemented in OPENFOAM® for multi-objective geometry optimization based on the continuous adjoint. The adjoint method has a large advantage over traditional optimization approaches in that its cost is not dependent upon the number of parameters being optimized. This characteristic can be used to treat every cell in the computational domain as a tunable parameter - effectively switching cells "on" or "off" depending on whether this action will help improve the objectives.

Air conditioning acoustics have become of paramount importance in electric vehicles, where noise from electromechanical components is no longer masked by the presence of the internal combustion engine. In a car HVAC systems, the coolant compressor is one of the most important sources in terms of vibration and noise generation. The paper, the generated structural noise is studied in detail on a prototype installation, and the noise transmission and propagation mechanisms are analyzed and discussed. Through ”in situ” measurements and virtual point transformation, the rotor unbalance forces and torque acting within the component are identified. The dynamic properties of the rubber mounts, installed between the compressor and its support, are identified thanks to matrix inversion methods. To assess the quality of the proposed procedure, the synthesized sound pressure level is compared with experimental SPL measurements in different operational conditions.