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The Application of E-Fuel Oxymethylene Ether OME1 in a virtual Heavy-Duty Diesel Engine for ultra-low Emissions

Universitat Stuttgart-Qirui Yang, Michael Bargende
FKFS-Michael Grill
  • Technical Paper
  • 2020-01-0349
To be published on 2020-04-14 by SAE International in United States
For long haul transport, diesel engine due to its low fuel consumption and the low operating costs will remain dominant over the long term. In order to achieve CO2 neutrality, the use of electricity-based, synthetic fuels (e-fuels) provides a solution. Especially the group of oxymethylene ethers (OME) is considered promising for its soot-free combustion. The new fuel properties and combustion characteristics place new demands on engine design and also open up new degrees of freedom to operate diesel engines. In this work, the effects of dimethoxymethane (OME1) were investigated by means of 1D simulation at three different operating points on a virtual truck diesel engine. The subsystems of fuel injection, air path and exhaust gas were sequentially adjusted for the purpose of low emissions, especially low nitrogen oxides (NOx). Thanks to the inexistent soot-NOx trade-off, NOx can be considerably reduced using high exhaust gas recirculation (EGR) for a nearly stoichiometric operation, without compromising power output. Conceivable configurations of exhaust aftertreatment system were analyzed. At last, a holistic layout of a future OME-powered engine was proposed.
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Virtual Investigation of Real Fuels by Means of 3D-CFD Engine Simulations

Universitat Stuttgart-Michael Bargende
FKFS-Francesco Cupo, Marco Chiodi
  • Technical Paper
  • 2019-24-0090
Published 2019-09-09 by SAE International in United States
The reduction of both harmful emissions (CO, HC, NOx, etc.) and gases responsible for greenhouse effects (especially CO2) are mandatory aspects to be considered in the development process of any kind of propulsion concept. Focusing on ICEs, the main development topics are today not only the reduction of harmful emissions, increase of thermodynamic efficiency, etc. but also the decarbonization of fuels which offers the highest potential for the reduction of CO2 emissions. Accordingly, the development of future ICEs will be closely linked to the development of CO2 neutral fuels (e.g. biofuels and e-fuels) as they will be part of a common development process. This implies an increase in development complexity, which needs the support of engine simulations. In this work, the virtual modeling of real fuel behavior is addressed to improve current simulation capabilities in studying how a specific composition can affect the engine performance. The goal is to create a series of models that allow to virtually investigate different fuels and to minimize, as much as possible, the costly and time-consuming experimental tests. In…
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Investigation of Flame Propagation Description in Quasi-Dimensional Spark Ignition Engine Modeling

Universitat Stuttgart-Simon Malcher, Michael Bargende
Audi AG-Ulrich Baretzky, Hartmut Diel, Sebastian Wohlgemuth, Gordon Röttger
Published 2018-09-10 by SAE International in United States
The engine development process has been enhanced significantly by virtual engineering methods during the last decades. In terms of in-cylinder flow field, charge flow and combustion modelling, 3D-CFD (three dimensional) simulations enable detailed analysis and extended investigations in order to gain additional knowledge about design parameters. However, the computational time of the 3D-CFD is an obvious drawback that prevents a reasonable application for extensive analysis with varying speed, load and transient conditions. State-of-the-art 0D (zero dimensional) approaches close the gap between the demand of high computational efficiency and a satisfying accordance with experimental data. Recent improvements of phenomenological combustion approaches for gasoline spark ignition engines deal with the consideration of detailed flow parameters, the accuracy of the laminar flame speed calculation and the prediction of the knock limit. Little attention has been given to the influence of different combustion chamber designs on the prediction capability so far. This leads to an often used simplification consisting of a combustion chamber modeled as a disk and an acceptable inaccuracy of combustion modelling. With an increasing deviation of…
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A Simulation Study of Optimal Integration of a Rankine Cycle Based Waste Heat Recovery System into the Cooling System of a Long-Haul Heavy Duty Truck

Universitat Stuttgart-Michael Bargende
FKFS-Kangyi Yang, Michael Grill
Published 2018-09-10 by SAE International in United States
As a promising solution to improve fuel efficiency of a long-haul heavy duty truck with diesel engine, organic Rankine cycle (ORC) based waste heat recovery system (WHR) by utilizing the exhaust gas from internal combustion engine has continuously drawn attention from automobile industry in recent years. The most attractive concept of ORC-based WHR system is the conversion of the thermal energy of exhaust gas recirculation (EGR) and exhaust gas from Tailpipe (EGT) to kinetic energy which is provided to the engine crankshaft. Due to a shift of the operating point of the engine by applying WHR system, the efficiency of the overall system increases and the fuel consumption reduces respectively. However, the integration of WHR system in truck is challenging by using engine cooling system as heat sink for Rankine cycle. The coolant mass flow rate influences strongly on the exhaust gas bypass which ensures a defined subcooling after condenser to avoid cavitation of pump. The coolant temperature decides the condensation pressure which impacts on the efficiency of WHR system. This paper aims to investigate…
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Methodical Selection of Sustainable Fuels for High Performance Racing Engines

Universitat Stuttgart-Michael Bargende
Universität Stuttgart-Lea Schwarz
Published 2018-09-10 by SAE International in United States
As the importance of sustainability increases and dominates the powertrain development within the automotive sector, this issue has to be addressed in motorsports as well. The development of sustainable high-performance fuels defined for the use in motorsports offers technical and environmental potential with the possibility to increase the sustainability of motorsports at the same or even a better performance level. At the moment race cars are predominantly powered by fossil fuels. However due to the emerging shift regarding the focus of the regulations towards high efficient powertrains during the last years the further development of the used fuels gained in importance. Moreover during the last decades a huge variety of sustainable fuels emerged that offer a range of different characteristics and that are produced based on waste materials or carbon dioxide. This study investigates the question of which sustainable fuels offer the characteristics suitable for high-performance race engines. Equivalents to gasoline, diesel and natural gas are examined separately in order to present the options with various engine concepts. The requirements for a high-performance fuel are…
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Evaluation of Engine-Related Restrictions for the Global Efficiency by Using a Rankine Cycle-Based Waste Heat Recovery System on Heavy Duty Truck by Means of 1D-Simulation

Universitat Stuttgart-Michael Bargende
FKFS-Kangyi Yang, Michael Grill
Published 2018-04-03 by SAE International in United States
As a promising concept to improve fuel efficiency of a long-haul heavy duty truck with diesel engine, organic Rankine cycle (ORC) based waste heat recovery system (WHR) by utilizing the exhaust gas from internal combustion engine has continuously drawn attention from industry in recent years. The greatest achievable global efficiency may be, however, restricted by the engine. On one hand, engine operating conditions have direct impact on the temperature and the mass flow of exhaust gas, which is the waste heat source, on the other hand, the engine cooling system limits the heat rejection from the condenser of the WHR system. This paper aims to evaluate the impacts of the varied engine applications considering the effects of the WHR system on the global efficiency and engine emissions. A complex 0D/1D-simulation model for a turbocharged production heavy duty engine with low-/high-temperature cooling circuit and a WHR system with ethanol as working fluid have been established in GT-Suite. The WHR-System recovers the heat from high pressure exhaust gas recirculation as well as exhaust gas after turbocharger. The…
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A Quasi-Dimensional Charge Motion and Turbulence Model for Diesel Engines with a Fully Variable Valve Train

Universitat Stuttgart-Michael Bargende
IVK/FKFS University-Qirui Yang, Michael Grill
Published 2018-04-03 by SAE International in United States
With the increasingly strict emission regulations and economic demands, variable valve trains are gaining in importance in Diesel engines. A valve control strategy has a great impact on the in-cylinder charge motions, turbulence level, thus also on the combustion and emission formation. In order to predict in-cylinder charge motions and turbulence properties for a working process calculation, a zero−/quasi-dimensional flow model is developed for the Diesel engines with a fully variable valve train. For the purpose of better understanding the in-cylinder flow phenomena, detailed 3D CFD simulations of intake and compression strokes are performed at different operating conditions with various piston configurations.In the course of model development, global in-cylinder charge motions are assigned to idealized flow fields. Among them, swirl flow is characterized by an engine swirl number that is determined by both developments of the swirl angular momentum and the moment of inertia. The generation of swirl angular momentum during intake is estimated from the intake mass flow and instantaneous stationary swirl number. The latter is obtained from virtual flow bench simulations in consideration…
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A Simulative Study for Post Oxidation During Scavenging on Turbo Charged SI Engines

Universitat Stuttgart-Michael Bargende
FKFS-Torsten Guenther, Michael Grill
Published 2018-04-03 by SAE International in United States
Fulfilling exhaust emissions regulations and meet customer performance needs mainly drive the current engine development. Turbocharging system plays a key role for that. Currently turbocharging should provide highest engine power density at high engine speed by also allowing a very responsive performance at low end. This represents a trade-off in turbocharger development. A large scaled turbine allows having moderate exhaust gas back pressure for peak power region, but leading to loss of torque in low engine speed. In the last years of engine development scavenging helped to get away a bit from this trade-off as it increases the turbine mass flow and also reduces cylinder internal residual gas at low engine speed. The mostly in-use lean strategy runs air fuel ratios of closed to stoichiometric mixture in cylinder and global (pre catalyst) of λ = 1.05 to l = 1.3. This will be out of the narrow air fuel ratio band of λ = 1 to ensure NOx conversion in the 3-way-catalyst. The use of the rich strategy (in cylinder λ < 1, pre catalyst stoichiometric) increases significantly the brake specific fuel consumption…
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In-Situ Measurements of the Piston and Connecting Rod Dynamics Correlated with TEHL-Simulation Techniques

SAE International Journal of Engines

Universitat Stuttgart-Michael Bargende
Ford Werke GmbH-Harald Stoffels
  • Journal Article
  • 2017-24-0157
Published 2017-09-04 by SAE International in United States
High combustion pressure in combination with high pressure gradient, as they e.g. can be evoked by high efficient combustion systems and e.g. by alternative fuels, acts as broadband excitation force which stimulates natural vibrations of piston, connecting rod and crankshaft during engine operation. Starting from the combustion chamber the assembly of piston, connecting rod and crankshaft and the main bearings represent the system of internal vibration transfer. To generate exact input and validation values for simulation models of structural dynamic and elasto-hydrodynamic coupled multi-body systems, experimental investigations are done. These are carried out on a 1.5-l inline four cylinder Euro 6 Diesel engine. The modal behaviour of the system was examined in detail in simulation and test as a basis for the investigations.In an anechoic test bench airborne and structure-borne noises and combustion pressure are measured to identify the engine´s vibrational behaviour. To understand the behaviour of the connecting rod as the key component in more detail its elongation, using semiconductor strain gauges at the connecting rod shank and a linkage system, is also measured.…
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Evaluating Different Measures to Improve the Numerical Simulation of the Mixture Formation in a Spark-Ignition CNG-DI-Engine

Universitat Stuttgart-Bernhard Weigand
Robert Bosch GmbH-Andrea Twellmeyer, Fabian Kopple
Published 2017-03-28 by SAE International in United States
Compressed Natural Gas (CNG) is a promising alternative fuel for internal combustion engines as its combustion is fuel-efficient and lean in carbon dioxide compared to gasoline. The high octane number of methane gives rise to significant increase of the thermodynamic efficiency due to higher possible compression ratios. In order to use this potential, new stratified mixture formation concepts for CNG are investigated by means of numerical fluid simulations. For decades RANS methods have been the industry standard to model three-dimensional flows. Indeed, there are well-known deficiencies of the widely used eddy viscosity turbulence models based on the applied Boussinesq hypothesis. Reynolds stress turbulence models as well as scale resolving simulation approaches can be appealing alternative choices since they offer higher accuracy. However, due to their large computing effort, they are still mostly impractical for the daily use in industrial product development processes. A more suitable solution seems to be the application of an explicit algebraic Reynolds stress (EARSM) turbulence model based on a non-linear relation between the Reynolds stresses and the mean strain-rate. This allows…
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