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2010-10-25
Technical Paper
2010-01-2182
Markus Wenig, Michael Grill, Michael Bargende
Regarding further development of gasoline engines several new technologies are investigated in order to diminish pollutant emissions and particularly fuel consumption. The Homogeneous Charge Compression Ignition (HCCI) seems to be a promising way to reach these targets. Therefore, in the past years there had been a lot of experimental efforts in this field of combustion system engineering. Negative valve overlap with pilot injection before pumping top dead center (PTDC) and an “intermediate” compression and combustion during PTDC, followed by the main injection after PTDC, is one way to realize and to proper control a HCCI operation. For conventional CI and SI combustion the pressure trace analysis (PTA) is a powerful and widely used tool to analyse, understand and optimize the combustion process.
2010-04-12
Journal Article
2010-01-1270
David Lejsek, Andre Kulzer, Günter Hohenberg, Michael Bargende
The introduction of CO₂-reduction technologies like Start-Stop or the Hybrid-Powertrain and the future emissions limits require a detailed optimization of the engine start-up. The combustion concept development as well as the calibration of the ECU makes an explicit thermodynamic analysis of the combustion process during the start-up necessary. Initially, the well-known thermodynamic analysis of in-cylinder pressure at stationary condition was transmitted to the highly non-stationary engine start-up. There, the current models for calculation of the transient wall heat fluxes were found to be misleading. But with a fraction of nearly 45% of the burned fuel energy, the wall heat is very important for the calculation of energy balance and for the combustion process analysis.
2010-04-12
Technical Paper
2010-01-0820
Daniel Boland, Hans-Juergen Berner, Michael Bargende
The hybrid power train technology offers various prospects to optimize the engine efficiency in order to minimize the CO₂ emissions of an internal-combustion-engine-powered vehicle. Today different types of hybrid architectures like parallel, serial, power split or through-the-road concepts are commonly known. To achieve lowest fuel consumption the following hybrid electric vehicle drive modes can be used: Start/Stop, pure electric/thermal driving, recuperation of brake energy and the hybrid mode. The high complexity of the interaction between those power sources requires an extensive investigation to determine the optimal configuration of a natural-gas-powered SI engine within a parallel hybrid power train. Therefore, a turbocharged 1.0-liter 3-cylinder CNG engine was analyzed on the test bench. Using an optimized combustion strategy, the engine was operated at stoichiometric and lean air/fuel ratio applying both high- and low-pressure EGR.
2013-09-08
Journal Article
2013-24-0149
Marco Chiodi, Antonella Perrone, Paolo Roberti, Michael Bargende, Alessandro Ferrari, Donatus Wichelhaus
In the last years motorsport is facing a technical revolution concerning the engine technology in every category, from touring car championships up to the F1. The strategy of the car manufacturers to bring motorsport engine technology closer to mass production one (e.g. turbo-charging, downsizing and direct injection) allows both to reduce development costs and to create a better image and technology transfer by linking motorsport activities to the daily business. Under these requirements the so-called Global Race Engine (GRE) concept has been introduced, giving the possibility to use one unique engine platform concept as basis for different engine specifications and racing categories. In order to optimize the performance of this kind of engines, especially due to the highly complex mixture formation mechanisms related to the direct injection, it is nowadays mandatory to resort to reliable 3D-CFD simulations.
2013-09-08
Technical Paper
2013-24-0047
Johannes Haag, Florian Kock, Marco Chiodi, Oliver Mack, Michael Bargende, Clemens Naumann, Nadezhda Slavinskaya, Alex Heron, Uwe Riedel, Cornelius Ferrari
In this paper the development approach and the results of numerical and experimental investigations on homogeneous charge compression ignition in a free piston engine are presented. The Free Piston Linear Generator (FPLG) is a new type of internal combustion engine designed for the application in a hybrid electric vehicle. The highly integrated system consists of a two-stroke combustion unit, a linear generator, and a mass-variable gas spring. These three subsystems are arranged longitudinally in a double piston configuration. The system oscillates linearly between the combustion chamber and the gas spring, while electrical energy is extracted by the centrally arranged linear generator. The mass-variable gas spring is used as intermediate energy storage between the downstroke and upstroke. Due to this arrangement piston stroke and compression ratio are no longer determined by a mechanical system.
2011-04-12
Technical Paper
2011-01-0373
Andreas Schmid, Michael Grill, Hans-Juergen Berner, Michael Bargende
Turbocharged SI-DI-engines in combination with a reduction of engine displacement (“Downsizing”) offer the possibility to remarkably reduce the overall fuel consumption. In charged mode it is possible to scavenge fresh unburnt air into the exhaust system if a positive slope during the overlap phase of the gas exchange occurs. The matching of the turbo system in SI-engines always causes a trade-off between low-end torque and high power output. The higher mass flow at low engine speeds of an engine using scavenging allows a partial solution of this trade-off. Thus, higher downsizing grades and fuel consumption reduction potential can be obtained. Through scavenging the global fuel to air ratio deviates from the local in-cylinder fuel to air ratio. It is possible to use a rich in-cylinder fuel to air ratio, whereas the global fuel to air ratio remains stochiometrical.
2011-09-11
Technical Paper
2011-24-0024
Annelies Vandersickel, Yuri Wright, Konstantinos Boulouchos, Sebastian Beck, Michael Bargende
Compact and computationally efficient reaction models capable of accurately predicting ignition delay and heat release rates are a prerequisite for the development of strategies to control and optimize HCCI engines. In particular for full boiling range fuels exhibiting two-stage ignition a tremendous demand exists in the engine development community. To this end, in a previous investigation, a global reaction mechanism was developed and fitted to data from shock tube experiments for n-heptane and five full boiling range fuels. By means of a genetic algorithm, for each of these fuels, a set of reaction rate parameters (consisting of pre-exponential factors, activation energies and concentration exponents) has been defined, without any change to the model form.
2011-06-09
Technical Paper
2011-37-0018
Michael Auerbach, Markus Ruf, Michael Bargende, Hans-Christian Reuss, Rene Van Doorn, Friedrich Wilhelm, Immanuel Kutschera
An approach for model-based control strategy design for diesel hybrid drive-trains has been developed, permitting the reduction of fuel consumption as well as of exhaust gas emissions. The control strategy consists of four core-functions: the SOC-management, the operation mode determination, the gear selection, and the thermal monitoring. Based on those different interpretations, a control strategy can be designed that leads to great reductions in fuel consumption or alternatively to a mentionable decline of nitrous oxides. In this trade-off, both aims can not be optimized at a time. Though, the strategy to be used is a compromise, designs for control strategies are possible that reduce both for a significant amount. Extending this control strategy by adding functions for transient behavior at start-up and load changes; phlegmatization enables additional potentials for emission reduction.
2011-06-09
Technical Paper
2011-37-0006
Marco Chiodi, Alessandro Ferrari, Oliver Mack, Michael Bargende, Donatus Wichelhaus
Until a few years ago the discussion of reduction of CO₂ emissions was completely out of place in motorsports. Nowadays, also in this field, car manufacturers want to investigate different approaches towards a more responsible and sustainable concept. For this target an interesting and feasible solution is the use of methane as an alternative fuel. At the 2009 edition of the 24-hour endurance race of the Nürburgring the Volkswagen Motorsport GmbH, in addition to vehicles powered by gasoline engines, introduced two vehicles powered by turbocharged CNG engines. The aim was to prove that also an "environment-friendly" concept is able to provide the required efficiency, dynamic and reliability for a successful participation in motorsports. After the success in the 2009 edition the engagement has been continued in 2010; this time exclusively with CNG vehicles.
2004-10-25
Technical Paper
2004-01-3004
Marco Chiodi, Hans-Jürgen Berner, Michael Bargende
The research institute FKFS in cooperation with the IVK Universität Stuttgart has recently presented QuickSim, a 3D-CFD-tool, that works integrated into the commercial 3D-CFD-code Star-CD. QuickSim has been developed to cover a vacancy in the market of simulation programs for engine development. The code introduces a new concept in the 3D-CFD-simulation of internal combustion engines (SI-Manifold-Injection and SI-GDI), that drastically reduces the CPU-time in comparison to a conventional 3D-CFD-simulation. QuickSim, as a 3D-CFD-tool, combines the advantages of local resolution of the fluid-dynamical field of internal combustion engines exactly like that provided by traditional 3D-CFD-simulations and the versatility and clearness of the real working-process analysis (WP) and of the full 1D-flow calculations. The CPU-time always remains in an acceptable range (few hours over a full operating cycle for a single-processor computing simulation).
2004-10-25
Technical Paper
2004-01-3053
Uwe Koehler, Michael Bargende
The presented results are part of a research project to create a universal residual gas fraction model. It is supported by the „Forschungsvereinigung Verbrennungs-kraftmaschinen e.V. (FVV)”. In the research project an universal formula has been developed which allows the determination of the residual gas fraction in allkind of IC engines. The formula is valid for naturally aspirated engine, turbo and super charged, variable valve timing and fully variable valve trains, as well. The formula (constant approach) developed during the project is based on variables like time averaged intake and exhaust pressure, exhaust temperature and geometric engine data which were measured on the test bench. As a result, online and real time calculation is possible already while the engine is running. This implies that the formula can be used within the engine control unit for control purposes.
2011-09-11
Technical Paper
2011-24-0141
Alessandro Ferrari, Marco Chiodi, Michael Bargende, Paolo Roberti, Federico Millo, Donatus Wichelhaus
In Motorsports the understanding of the real engine performance within a complete circuit lap is a crucial topic. On the basis of the telemetry data the engineers are able to monitor this performance and try to adapt the engine to the vehicle's and race track's characteristics and driver's needs. However, quite often the telemetry is the sole analysis instrument for the Engine-Vehicle-Driver (EVD) system and it has no prediction capability. The engine optimization for best lap-time or best fuel economy is therefore a topic which is not trivial to solve, without the aid of suitable, reliable and predictive engineering tools. A complete EVD model was therefore built in a GT-SUITE™ environment for a Motorsport racing car (STCC-VW-Scirocco) equipped with a Compressed Natural Gas (CNG) turbocharged S.I. engine and calibrated on the basis of telemetry and test bench data.
2011-09-11
Technical Paper
2011-24-0140
Marco Chiodi, Alessandro Ferrari, Oliver Mack, Michael Bargende, Donatus Wichelhaus
Methane as an alternative fuel in motorsports? Actually this solution is well known for the reduction of CO₂ emissions but apparently it does not really awake race feelings. At the 2009 edition of the 24-hour endurance race on the Nürburgring the Volkswagen Motorsport GmbH, in addition to vehicles powered by gasoline engines, introduced two vehicles powered by innovative turbo-charged CNG engines for the first time. The aim was to prove, that also an "environment-friendly" concept is able to provide the required efficiency, dynamic and reliability for a successful participation in motorsports. After the success in the 2009 edition the engagement has been continued also in 2010, this time exclusively with CNG vehicles. Focusing on the CO₂ emission, reclusively the higher hydrogen content of methane which represents the main component of NG leads to a CO₂ reduction during the combustion of about 20% compared to gasoline.
2015-09-06
Technical Paper
2015-24-2531
Marco Leonetti, Michael Bargende, Martin Kreschel, Christoph Meier, Horst Schulze
Abstract Due to the demands for today's passenger cars regarding fuel consumption and emissions, exhaust turbo charging has become a fundamental step in achieving these goals. Especially in upper and middle class vehicles it is also necessary to consider the noise comfort. Today, floating bushings are mainly used as radial bearings in turbochargers. In the conventional operating range of the turbocharger dynamic instability occurs in the lubrication films of the bearings. This instability is transferred by structure-borne noise into audible airborne sound and known as constant tone phenomenon. This phenomenon is not the major contributor of the engine noise but its tonal character is very unpleasant. In order to gain a more detailed understanding about the origin of this phenomenon, displacement sensors have been applied to the compressor- and the turbine-side of the rotor, to be able to determine the displacement path.
2015-09-06
Technical Paper
2015-24-2545
Florian Winke, Hans-Juergen Berner, Michael Bargende
Abstract This study presents a comparison of different approaches for the simulation of HEV fuel consumption. For this purpose a detailed 1D-CFD model within an HEV drivetrain is compared to a ‘traditional’ map-based combustion engine model as well as different types of simplified engine models which are able to reduce computing time significantly while keeping the model accuracy at a high level. First, a simplified air path model (fast running model) is coupled with a quasi dimensional, predictive combustion model. In a further step of reducing the computation time, an alternative way of modeling the in cylinder processes was evaluated, by replacing the combustion model with a mean value model. For this approach, the most important influencing factors of the 1D-CFD air path model (temperature, pressure, A/F-ratio) are used as input values into neural nets, while the corresponding outputs are in turn used as feedback for the air path model.
2015-09-06
Technical Paper
2015-24-2469
Marlene Wentsch, Antonella Perrone, Marco Chiodi, Michael Bargende, Donatus Wichelhaus
Abstract Comparative analyses of a high-performance 4-cylinder DISI-engine and its equivalent single-cylinder research engine were performed by means of fast response 3D-CFD simulations. Both engines have identical geometries of intake and exhaust channels, cylinder head and piston. The used 3D-CFD tool QuickSim was developed at the Forschungsinstitut für Kraftfahrwesen und Fahrzeugmotoren Stuttgart (FKFS), particularly for the numerical simulation of internal combustion engines (ICE). A calibration of the air consumption enabled a comparison of in-cylinder processes, including charge motion, mixture formation and combustion. All calculated operating points showed a similar trend. Deviations during the gas exchange phase led to a higher turbulence level and hence combustion velocity for the single-cylinder research engine. This resulted in a slightly higher maximum cylinder pressure and indicated mean effective pressure.
2007-09-16
Technical Paper
2007-24-0016
Simon Haas, Michael Bargende, Hans-Jürgen Berner
Because of its outstanding efficiency, the direct-injection diesel engine is the preferred drive source in many fields. However, its emission behavior, especially with regard to particulate and nitrogen-oxide emissions, is problematic. A promising approach to reducing emissions inside the engine is presented by various (partially) homogeneous diesel combustion processes, which use suitable mixture formation and combustion management to prevent the formation of nitrogen-oxide and soot. In this paper, starting out from an ideally homogeneous combustion process with manifold injection, two further partially homogeneous combustion processes with internal mixture formation are examined. With regard to the maximum obtainable indicated mean effective pressure and the combustion noise, the ideally homogeneous combustion process proved - in the examined configuration - not to be desirable.
2010-04-12
Technical Paper
2010-01-0151
Michael Grill, Michael Bargende, Dominik Rether, Andreas Schmid
Two combustion models are presented: A quasi-dimensional approach, based on the injection shape and an empirical model. Both models have computation times of less than one second per cycle. The quasi-dimensional approach for CI combustion discretizes the injection jet in slices. Pilot-injections are modeled as separate zones. The forecast capability and the limitations of the model are discussed on the basis of measurements. Mentioned above the base of the quasi-dimensional model is the injection rate. Often it is difficult to obtain these data. There is therefore another empirical approach for combustion, which does not need the injection rate as input. Both models have to be calibrated. This can be done by an automatic calibration tool on the basis of the advanced Powell method. The differences and advantages compared with other optimization methods are shown. Emission-simulation models are highly important in simulating CI engines.
2010-04-12
Journal Article
2010-01-0150
Dominik Rether, Michael Grill, Andreas Schmid, Michael Bargende
A new phenomenological CI combustion model was developed. Within this model the given injection rate may contain an arbitrary number of injections during one cycle. Another target was a short computation time of one second per cycle on average. The new approach should also have the ability to simulate a wide engine spectrum from passenger-car engines through to marine engines. The ignition delay is calculated separately for each single injection. In this way the model depicts the influence of pilot injections on the ignition delay of proximate injections. Each pilot injection is modeled as a single air-fuel mixture cloud with air entrainment. The burn rate of the pilot injection is modeled as a function of flame propagation and of the current local excess air ratio. If the local excess air ratio becomes too lean the pilot combustion stops or does not start at all. Main and post-injections are calculated by means of a slice approach.
2010-04-12
Journal Article
2010-01-0149
Michael Grill, Michael Bargende
The main objective of the FVV-project “Cylinder Module” was the development of a profoundly modular designed concept for object-oriented modeling of in-cylinder processes of internal combustion engines. It was designed in such a way, that it can either be used as a stand-alone real working-process calculation tool or in tools for whole vehicle simulations. It is possible to run the “Cylinder Module”-code inside the FVV-“GPA”-software for transient vehicle and driving cycle simulations and it is possible to use the graphical user interface “ATMOS” of the “GPA”-project. The code can also be used as a user-subroutine in 1-D-flow simulation codes. Much effort was spent on the requirements of flexibility and expandability in order to be well prepared to cope with the diversity of both today's and future tasks. The code is freely available for members of the German Research Association for Combustion Engines (FVV).
2009-11-02
Journal Article
2009-01-2659
Andreas Schmid, Michael Grill, Hans-Jürgen Berner, Michael Bargende, Sascha Rossa, Michael Böttcher
The simulation of the combustion process is an essential part of the internal combustion engine development. For simulating whole engine maps quasi-dimensional models in combination with 1-D-flow simulations are widely used. This procedure is beneficial due to short computation times and accurate forecast capability of quasi-dimensional combustion models. For the simulation of homogeneous SI-engines the two-zone entrainment model is usually used, which is based on hemispherical flame propagation. In this work a new approach for the quasi-dimensional calculation of the stratified SI-engine combustion process is proposed, which is based on the two-zone entrainment model. This proven approach was extended with regard to the inhomogeneous air/fuel composition of stratified SI-engines that make a two-zone treatment not sufficient. Therefore, four unburnt zones are defined: a rich zone, a stoichiometrical zone, a lean zone and a remaining air zone.
2005-09-11
Technical Paper
2005-24-026
Michael Bargende, Hans-Jürgen Berner
To demonstrate the potential of a CO2-minimized propulsion concept a study of a natural-gas, micro-hybrid powertrain was carried out. The basis was built by experimental investigations of a turbocharged 1.0-l, 3-cylinder engine operated at stoichiometric and lean air/fuel ratio with EGR and an optimized combustion strategy. With the results of this study a still existing model for micro-hybrid vehicles was filled and the CO2 emissions for several concepts were calculated. It could be shown that CO2 improvements of 30 to 40% for the IC engine and up to 50% for the complete micro-hybrid propulsion system accompanied with better driveability are possible.
2006-09-14
Technical Paper
2006-01-3000
Marco Chiodi, Hans-Jürgen Berner, Michael Bargende
Natural gas as a fuel for internal combustion engines is a combustion technology showing great promise for the reduction of CO2 and particulate matter. To demonstrate the potential of natural gas direct injection, especially in combination with supercharging, some experimental investigations were carried out using a single-cylinder engine unit with lateral injector position. For this purpose different injection valve nozzles, piston crown geometries as well as operating strategies were investigated. First experimental results show that it is also possible to better support the combustion process by providing a late injection of a part of the fuel, near ignition point, so that the additional induced turbulence can speed up the flame propagation 1 Mixture formation with gaseous fuels due to its low mass density is more critical than in gasoline engines, because even high injection velocities still produce very low fuel penetration.
2000-03-06
Technical Paper
2000-01-1239
Burkhard Scholz, Michael Bargende
For basic research on the piston group a new simulation technique is developed using the contact algorithm of a commercial FE-code (MARC). Several improvements were made in order to adapt the MARC solver to the problem of sliding and dynamic contact. The first computations, a real transient analysis simulating the piston group, of both a two-stroke engine and a modern direct injected four-stroke Diesel engine for passenger cars, show that the new method is able to calculate the movements, velocities and accelerations of the piston. The quality of the results is mainly influenced by the hydrodynamic effects.
2002-03-04
Technical Paper
2002-01-0901
Udo G. Riegler, Michael Bargende
The setting of boundary conditions on the boundaries of a 3D-CFD grid under certain conditions is a source of significant errors. The latter might occur by numerical reflection of pressure waves on the boundary or by incorrect setting of the chemical composition of the gas mixture in recirculation zones (e.g. in the intake manifold of internal combustion engines when the burnt gas from the cylinder enters the intake manifold and passes the boundary of the CDF-grid. When the flow direction is changed the setting of pure new charge on the boundary leads to errors). This type of problems should receive attention in operation points with low engine speed and load. The direct coupling of a 3D-CFD program (Star-CD) with a 1D-CFD program (GT-Power) is done by integration of the 3D-grid of the engine component as a „CFD-component” of the 1D computational model of a complete engine.
2001-09-24
Technical Paper
2001-01-3596
Burkhard Scholz, Michael Bargende
Today, mechanical systems such as the piston groups of internal combustion engines are simulated using Multiple Body-System (MBS) - approaches. However, the use of these models is restricted to a few problems as their adaptability is limited. The simulation of mechanical systems only by means of finite elements shows great promise for the future. In order to consider lubrication effects between two touching bodies of a mechanical system, a hydrodynamic contact algorithm (HCA) for finite element (FE) applications was developed. This paper discusses the technical background and first results for the simulation of a piston group using this new approach.
2001-09-24
Technical Paper
2001-01-3601
Marco Chiodi, Michael Bargende
Improvement of heat-transfer calculation for SI-engines in the three-dimensional simulation has been achieved and widely been tested by using a phenomenological heat-transfer model. The model is based on the local application of an improved Re-Nu-correlation (dimensional analysis) proposed by Bargende [1]. This approach takes advantage of long experience in engine heat transfer modeling in the real working process analysis. The results of numerous simulations of different engine meshes show that the proposed heat-transfer model enables to calculate the overall as well as the local heat transfer in good agreement with both real working process analyses and experimental investigations. The influence of the mesh structure has also been remarkably reduced and compared to the standard wall function approach, no additional CPU-time is required.
2016-04-05
Technical Paper
2016-01-0801
Dimitri Seboldt, David Lejsek, Marlene Wentsch, Marco Chiodi, Michael Bargende
Abstract CNG direct injection is a promising technology to promote the acceptance of natural gas engines. Among the beneficial properties of CNG, like reduced pollutants and CO2 emissions, the direct injection contributes to a higher volumetric efficiency and thus to a better driveability, one of the most limiting drawbacks of today’s CNG vehicles. But such a combustion concept increases the demands on the injection system and mixture formation. Among other things it requires a much higher flow rate at low injection pressure. This can be only provided by an outward-opening nozzle due to its large cross-section. Nevertheless its hollow cone jet with a specific propagation behavior leads to an adverse fuel-air distribution especially at higher loads under scavenging conditions. This paper covers numerical and experimental analysis of CNG direct injection to understand its mixture formation.
2016-04-05
Technical Paper
2016-01-1002
Benjamin Kaal, Michael Grill, Michael Bargende
Abstract This paper presents a quasi-dimensional emission model for calculating the transient nitric oxide emissions of a diesel engine. Using conventional and high-speed measurement technology, steady-state and transient emissions of a V6 diesel engine were examined. Based on measured load steps and steady-state measurements a direct influence of the combustion chamber wall temperature on the nitric oxide emissions was found. Load steps to and from, as well as steady-state measurements down to almost stoichiometric global combustion air ratios were used to examine the behavior of nitric oxide formation under these operating conditions. An existing emission model was expanded in order to represent the direct influence of the combustion chamber wall temperature on the nitric oxide emissions as well as enabling the forecasting of nitric oxide emissions at low global combustion air ratios: Both particularly important aspects for the simulation of transient emissions.
2015-04-14
Technical Paper
2015-01-0385
Fabian Köpple, Paul Jochmann, Alexander Hettinger, Andreas Kufferath, Michael Bargende
Abstract The emission of particulate matter from future GDI engines has to be optimized, to comply with more stringent emission standards such as EU6. Therefore, the mechanisms responsible for the formation of particles have to be analyzed in detail. The understanding of the in-cylinder processes, necessary for this purpose, can only be achieved by a complementary use of optically accessible single-cylinder engines as well as the numerical simulation. This however leads to great demands on the 3D flow simulation. In this paper the complete CFD approach, incorporating a detailed description of the entire underlying model chain is shown. Particularly the wall surface temperature and the temperature drop due to the interaction with liquid fuel spray were identified as important parameters influencing the spray-wall interaction and thus also the particulate emissions.
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