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Results from numerical computations performed to represent the transient behavior of vaporizing sprays injected into a constant volume chamber and into a High Speed Direct Injection combustion chamber are presented. In order to describe the liquid phase, a new model has been developed from ideas brought forward by recent experimental results (Siebers, 1999) and numerical considerations (Abraham, 1999). The liquid penetration length is given by a 1D model which has been validated on a large number of experiments. In the 3D calculation, break-up, vaporization, drag, collision and coalescence are not modeled. The mass, momentum and energy transfers from the liquid to the gas phase are imposed from the nozzle exit surface to the liquid penetration length. This model enables us to reach time step and grid-independent results. The gas penetrations obtained with the model are checked against experimental results in a constant volume chamber (Verhoeven et al., 1998).

The development process of a combustion engine is now a days strongly influenced by future emission regulations which require further reduction in fuel consumption and precise control of combustion process based on Intake air measurement, during engine development. Intake air flow meters clearly differentiate themselves from typical industrial gas flow meters because of their ability to measure extremely dynamic phenomenon of combustion engine. Thus, high internal data acquisition rate, short response time, ability to measure pulsating and reverse flows with lower measurement uncertainty are the factors that ensures the reliability of the results without being affected by ambient influences, sensor contamination or sensor aging. The AVL developed FLOWSONIX™ is based on ultrasonic transit time measuring principle with broad-band Capacitive Ultrasonic Transducer (CUT) characterized by an excellent air impedance matching strongly distinguishes itself by fulfilling all those requirements.

The development of low noise engines and vehicles, accompanied by the reduction of costs and development time, can be obtained only if the design engineer is supported by complex calculation tools in a concurrent engineering process. In this respect, the reduction of vibrations (passenger comfort) and of vehicle noise (accelerated pass by noise) are important targets to meet legislative limits. AVL has been developing simulation programs for the dynamic-acoustic optimization of engines and gear trains for many years. To simulate the structure-born and air-born noise behavior of engines under operating conditions, substantial efforts on the mathematical simulation model are necessary. The simulation tool EXCITE, described in this paper, allows the calculation of the dynamic-acoustic behavior of power units.

As an alternative to the element based methods, recently a wave based technique (WBT) has been developed. Since it is based on the indirect Trefftz approach, exact solutions of the governing differential equation are used to approximate the dynamic field variables. This paper discusses the extensions of the WBT for the analysis of engine noise radiation problems in 3 dimensions under anechoic conditions. Furthermore, necessary extensions of shape functions, numerical integration and a methodology to create a WBT radiation models are described. The performance of the method compared to a commercial BEM solution is demonstrated with a real engine example.

In recent years several new gasoline engine technologies were introduced in order to reduce fuel consumption. Controlled autoignition seems to be an alternative to stratified part load operation, which is handicapped due to it's lean aftertreatment system for world wide application. The principal advantages of controlled auto ignition combustion under steady state operation - combining fuel economy benefits similar to stratified charge systems with nearly negligible NOx and soot emissions - are already well known. With the newly developed AVL- CSI system (Compression and Spark Ignition), a precise combustion control is achieved even under transient operation. For compensation of production and operation tolerances a cost optimized cylinder individual control was developed. Completely new functionalities of the engine management system are applied. This lean GDI concept complies with future emission standards without DeNOx catalyst and can be applied worldwide.

Exhaust emission legislation world-wide have a common trend towards very low limits, measured for compliance in transient cycles specific for the United States, Japan and Europe. The emission development strategy is focussing on lowest engine-out emissions to require a minimum of exhaust gas aftertreatment. The base engine concept is described and test results, complying with Euro 4, are shown. The emission reduction development for future regulations requires exhaust gas aftertreatment, test results are shown for US 2007, JNLTR and Euro 5. With exhaust gas aftertreatment, discussed in the appendix, the engine development is faced with a big challenge to ensure the minimum exhaust gas temperature required for their proper function.

Gasoline turbocharged direct injection (GTDI) engines, such as EcoBoost™ from Ford, are becoming established as a high value technology solution to improve passenger car and light truck fuel economy. Due to their high specific performance and excellent low-speed torque, improved fuel economy can be realized due to downsizing and downspeeding without sacrificing performance and driveability while meeting the most stringent future emissions standards with an inexpensive three-way catalyst. A logical and synergistic extension of the EcoBoost™ strategy is the use of E85 (approximately 85% ethanol and 15% gasoline) for knock mitigation. Direct injection of E85 is very effective in suppressing knock due to ethanol's high heat of vaporization - which increases the charge cooling benefit of direct injection - and inherently high octane rating. As a result, higher boost levels can be achieved while maintaining optimal combustion phasing giving high thermal efficiency.

This paper presents the results of an investigation on the influence of a duct’s geometry and shape on its acoustic length, which differs from its physical length by a factor referred to as end-correction. In addition to traditional parameters such as length and diameter, the author has investigated the effect of additional geometry features which are less commonly addressed in the technical literature, such as a diameter contraction or a bent section along the duct. The relative microphone position with respect to the pipe orifice and to the ground surface of the measurement environment has been investigated, showing negligible impact on the measurement results. The sound wave propagation within a pipe featuring a diameter contraction has then been analysed, showing the relationship between the pipe contraction shape and location and the pipe acoustic length.

The characteristically good fuel economy of the high speed direct injection diesel engine has led to increased market share as the power unit of passenger cars. This trend is particularly true in Europe and, if not halted prematurely by emissions legislation, is likely to continue. However, another characteristic of the high speed DI engine is increased noise and vibration over its gasoline counterpart. This has meant that additional noise and vibration measures are required in order to approach the competitive refinement levels of gasoline engine installations. This paper considers some of the characteristic diesel engine noise and vibration problems associated with vehicle installation and passenger comfort. The paper also discusses subjective and objective assessment and considers approaches to engineering more desirable sound quality.

The latest legislation requires the automotive industry to once again reduce the emission levels of their latest vehicles. This leads to a new challenge in the field of emission measurement, because the concentrations of certain components of the exhaust gases are extremely low. For current measurement devices, which are recommended by the legislation, it is almost impossible to determine such low emission levels with the necessary accuracy. This study evaluates the features of an improved CVS system (Constant Volume Sampling) with the possibility of heating and the ability of changing flow rates quickly. Possible solutions are discussed and the properties of data measured with test facilities which are prepared to cover S-ULEV and EURO IV applications are described. The tests were performed on a dynamic engine test bed which was equipped with such a CVS system and with emission analyzing systems for raw exhaust and diluted measurements.

Gasoline direct injection is one of the main issues of actual worldwide SI engine development activities. It requires a comprehensive system approach from the basic considerations on optimum combustion system configuration up to vehicle performance and driveability. The general characteristics of currently favored combustion system configurations are discussed in this paper regarding both engine operation and design aspects. The engine performance, especially power output and emission potential of AVL's DGI engine concept is presented including the interaction of advanced tools like optical diagnostics and 3D-CFD simulation in the combustion system development process. The application of methods like tomographic combustion analysis for investigations in the multicylinder engine within further stages of development is demonstrated. The system layout and operational strategies for fuel economy in conjunction with exhaust gas aftertreatment requirements are discussed.

Accurate simulation tools are needed for rapid and cost effective engine development in order to meet ever tighter pollutant regulations for future internal combustion engines. The formation of pollutants such as soot and NOx in Diesel engines is strongly influenced by local concentration of the reactants and local temperature in the combustion chamber. Therefore it is of great importance to model accurately the physics of the injection process, combustion and emission formation. It is common practice to approximate Diesel fuel as a single compound fuel for the simulation of the injection and combustion process. This is in many cases sufficient to predict the evolution of the in-cylinder pressure and heat release in the combustion chamber. The prediction of soot and NOx formation depends however on locally component resolved quantities related to the fuel liquid and gas phase as well as local temperature.

In the near future the effort on the development of exhaust gas treatment systems must be increased to meet the stringent emission requirements. If the relevant physical and chemical models are available, the numerical simulation is an important tool for the design of these systems. This work presents a CFD model that allows to cover the full range of applications in this area. After a detailed presentation of the theoretical background and the modeling strategies results for the simulation of a close-coupled catalyst are shown. The presented model is also applied to the oxidation of nitrogen oxides, to a diesel particle filter and a fuel-cell reformer catalyst.

This report shows the methods, which AVL uses for the calculation of gear box noise. The analysis of the gear box structure (housing) is done using finite element method (FEM), thereby the natural frequencies are calculated as well as forced vibrations. As input for the FE calculation of the forced vibrations, the dynamic bearing forces of the shafts in the gear box or the dynamic tooth mesh are used. These forces are determined using the MBS (multi body system) software GTDYN, considering the torsional vibrations as well as axial and bending vibrations. Several examples of calculation results for the investigation of the gear dynamics are shown within the scope of this report.

The paper outlines and discusses the possibilities of a new instrumentation tool for the analysis of engine and gearbox noise radiation and the prediction of pass-by noise from powertrain test cell measurements. Based on a 32 channel data acquisition board, the system is intended to be quick and easy to apply in order to support engineers during their daily work in the test cell. The pass-by prediction is a purely experimental approach with test cell recordings being weighted by measured transfer functions (from the powertrain compartment to the pass-by point).

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.

Due to durability and lifetime requirements, the timing drive systems of modern passenger car engines are often equipped with chain drives. Chain driven systems are usually more critical in view of NVH compared to synchronous belt-drives. Mainly the polygonal effect and the related phenomena, like impacts caused by the meshing between the chain-links and impacts in the engagement/disengagement regions of guides and sprockets, lead to an increased excitation of the engine's structure. Since the polygonal effect occurs with the meshing frequency, the excited vibrations are basically narrow banded and can finally be recognized as an annoying whine-noise. This paper describes the modeling (MBS) of the entire timing-drive system containing a bushing-chain-drive, camshafts and all connected single valve trains. The investigations carried out are mainly focused on the primary dynamics of the chain drive and the forces which are transferred to the engine's structure.

The introduction of more stringent standards for engine emissions requires continuous improvement of exhaust gas aftertreatment systems. Modern systems require a combined design and application of different aftertreatment devices. Computer simulation helps to investigate the complexity of different system layouts. This study presents an overall aftertreatment modeling framework comprising dedicated models for pipes, oxidation catalysts, wall flow particulate filters and selective catalytic converters. The model equations of all components are discussed. The individual behavior of all components is compared to experimental data. With these well calibrated models a simulation study on a DOC-DPF-SCR exhaust system is performed. The impact of pipe wall insulation on the overall NOx conversion performance is investigated during four different engine operating conditions taken from a heavy-duty drive cycle.

Beside performance, handling and styling the sound characteristic of a motorcycle is a very important feature for the acceptance of the product by the customers and therefore the commercial success of a new product. Creating a special brand sound becomes more and more important to create a product that can be easily distinguished from competitor products and is therefore considered to be something special. On the other hand the legal limits in terms of pass - by noise allow for a very little margin for the creation of a special sound. During the product sound design phase the different perceptions of the rider wearing a helmet and pedestrians have to be considered. In passenger cars sound design has been known for a long time and the creation of a special sound for the driver inside the passenger compartment can be achieved with little influence on the exterior noise and therefore on the noise which is limited by legislation.

This paper focuses on psychoacoustical experiments for the assessment of roughness by using vehicle interior noise. The experimental design is carried out carefully to derive reliable data for further analysis with objective parameters. Apart from the acoustical properties of the recording/playback system the different meanings of the word roughness are taken into account, because each person has its own interpretation of ‘roughness’ differing between the phenomenons of roughness, r-roughness, rumble, harshness, fluctuation strength, etc.. An important preparation for psychoacoustical experiments is a clear definition of the sound attribute under investigation by using typical examples. Furthermore, accidental influences of other psychoacoustical parameters like the influence of loudness have to be avoided.