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Effects of Bio-Alcohol Fuel Blends on the Aging of Engine Lubricating Oil

University of Rostock-Sascha Prehn, Christine Vogel, Bert Buchholz
Published 2018-09-10 by SAE International in United States
Bio-alcohol fuel blends will gain in importance for future mobility. The driving force is the necessary reduction of greenhouse gases and harmful exhaust gas components. The new fuels offer advantages in engine combustion and resulting exhaust emissions because of the short-chained molecules and resulting low C/H ratio as well as the higher oxygen content. The aim of the project is a systematic analysis and evaluation of the effects of two bio-alcohol blends on the lubrication oil ageing of a gasoline-driven Euro 6 passenger car engine. For this reason a test engine was operated with three different fuels: a fossil gasoline (E0) without bio-alcohol components, a blend containing 30% vol ethanol (E30) and a blend containing 15% vol methanol (M15). During the engine test, gas of the cylinder charge and blow-by has been sampled and analyzed by ion chromatography regarding short-chained organic and inorganic acids. Based on these results the acid entries in lubricating oil were determined. In addition to the acid entries the entry of fuel into the lubricating oil were determined and compared for…
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Analysis of Cycle-to-Cycle Variations of the Mixing Process in a Direct Injection Spark Ignition Engine Using Scale-Resolving Simulations

SAE International Journal of Engines

University of Rostock-Egon Hassel, Bert Buchholz
FVTR GmbH-Martin Theile
  • Journal Article
  • 2016-01-9048
Published 2016-11-16 by SAE International in United States
Since the mechanisms leading to cyclic combustion variabilities in direct injection gasoline engines are still poorly understood, advanced computational studies are necessary to be able to predict, analyze and optimize the complete engine process from aerodynamics to mixing, ignition, combustion and heat transfer. In this work the Scale-Adaptive Simulation (SAS) turbulence model is used in combination with a parameterized lagrangian spray model for the purpose of predicting transient in-cylinder cold flow, injection and mixture formation in a gasoline engine. An existing CFD model based on FLUENT v15.0 [1] has been extended with a spray description using the FLUENT Discrete Phase Model (DPM). This article will first discuss the validation of the in-cylinder cold flow model using experimental data measured within an optically accessible engine by High Speed Particle Image Velocimetry (HS-PIV). Afterwards, the parameterized spray model is validated using experimental data measured in a pressure spray chamber. Finally, results obtained with the combined model are discussed and used to analyze transient mixture formation and to give a detailed insight into cycle-to-cycle fluctuations associated with the…
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Multi-Objective Optimal Design of Parallel Plug-In Hybrid Powertrain Configurations with Respect to Fuel Consumption and Driving Performance

SAE International Journal of Alternative Powertrains

University of Rostock-Markus Schori, Torsten Jeinsch
IAV Automotive Engineering GmbH-Thomas Juergen Boehme, Matthias Rothschuh, Benjamin Frank, Matthias Schultalbers
  • Journal Article
  • 2014-01-1158
Published 2014-04-01 by SAE International in United States
In the past decade, various Plug-in Hybrid Electric Vehicles have been demonstrated which offer the potential of a significant reduction in fuel consumption and emission. However, this capability strongly depends on the sizing of the components, driver's usage profile and the quality of the energy management. These challenges require new optimization procedures for a systematical exploration of the design space with the objective of an optimal powertrain configuration. A novel optimization strategy based on a multi-objective problem formulation is proposed. The optimization procedure consists of a multi-objective genetic algorithm for determining the best design parameters with respect to fuel consumption and driving performance. The approach is combined with an analytical optimal control problem to find the optimal continuous and discrete control trajectories for the energy management.
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A Post-Catalyst Control Strategy Based on Oxygen Storage Dynamics

University of Rostock-Wolfgang Drewelow, Bernhard Lampe
IAV-Michael Tomforde, Matthias Schultalbers
Published 2013-04-08 by SAE International in United States
For compliance with future more stringent emission standards exhaust emissions must be reduced. One possibility is to improve air-fuel ratio control quality. The approach presented in this paper uses virtual sensors to get a rough picture of the spatial distribution of lambda and oxygen storage states across the catalyst. This additional process information is gathered by means of a novel model for three-way catalysts. A state-space controller is used to maintain oxygen storage states predicted by the model at desired levels. The proposed control strategy has been implemented on a turbocharged, direct injection engine and successfully validated by means of emission measurements. A comparison with a commonly used air-fuel ratio control strategy is presented.
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Solutions of Hybrid Energy-Optimal Control for Model-based Calibrations of HEV Powertrains

University of Rostock-Markus Schori, Bernhard Lampe
IAV Automotive Engineering-Thomas Juergen Boehme, Benjamin Frank, Matthias Schultalbers
Published 2013-04-08 by SAE International in United States
In this paper optimal control problems for hybrid powertrain vehicles with different drive-modes are considered and solved using numerical techniques. This leads to the formulation of hybrid optimal control problems. The aim is to find optimal controls and optimal switchings between the drive-modes to minimize a cost function resembling fuel consumption. The problem is nonlinear and subject to constraints concerning both controls and state. The techniques include indirect methods as well as direct optimization methods. Efficiency and accuracy are evaluated for all methods using simulation studies. An experimental test on a near mass-production vehicle confirms the usability of the direct optimization approach.
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Optimal Design Strategies for Different Hybrid Powertrain Configurations Assessed with European Drive Cycles

University of Rostock-Wolfgang Drewelow
IAV Automotive Engineering-Thomas Juergen Boehme, Bernd Becker, Michael Ruben-Weck, Matthias Rothschuh, Alexander Boldt, Christoph Rollinger, Robert Butz, Heiko Rabba
Published 2013-04-08 by SAE International in United States
The quality of the powertrain design has a significant impact on the fuel consumption and emissions of hybrid vehicles. Lack of experience with these relatively new technologies, the enormous variety of hybrid powertrain configurations, and the multitude of components make this area an ideal application for computer-based modeling and optimizations. Global optimization techniques have the advantage to explore systematically the design space to find the optimal configuration space. In this paper, a systematic procedure for an optimal design of hybrid powertrain configurations using an evolutionary algorithm is proposed. It will be shown that the design steps for parallel and power-split configurations are quite similar. This results in a computing approach with high synergy effects and the ability to exchange components seamless to compare different ‘virtual’ configurations.
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Application of an Optimal Control Problem to a Trip-Based Energy Management for Electric Vehicles

SAE International Journal of Alternative Powertrains

University of Rostock-Bernhard Lampe
IAV Automotive Engineering-Thomas Juergen Boehme, Florian Held, Christoph Rollinger, Heiko Rabba, Matthias Schultalbers
  • Journal Article
  • 2013-01-1465
Published 2013-04-08 by SAE International in United States
A trip-based energy management strategy for electric vehicles (EVs) is proposed. It can use deterministic routing information obtained from, nowadays, available navigation systems and determines stochastic descriptions of process uncertainties such as stop events as unpredictable disturbances. A dynamic programming algorithm is used to calculate the optimal control trajectories required to reach the target destination safely and to suggest the driver an optimal driving style to maximize the battery range. The algorithm is implemented on a rapid prototyping platform using MATLAB/Simulink. Simulations and experimental results obtained from an EV prototype car are presented.
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Turbulence-Chemistry-Interaction Modelling in 3D-CFD for Study of Auto Ignition Phenomena

Henrik Hoffmeyer, Karsten Michels
University of Rostock-Christof Benz, Jürgen Nocke, Egon Hassel
Published 2012-04-16 by SAE International in United States
From the point of view of the customer purchasing a car the ecological as well as the price aspect is in the main focus today and in the years that come. This will increase due to global warming, the accelerated depletion of raw materials and significant price increases. Downsizing of spark ignition engines is an opportunity to lessen these shortcomings by decreasing the displacement volume of the engine and for a constant power increasing the load. In the case of extreme downsizing, especially in the case of low engine speed, auto ignition occurs in the air/fuel mixture. As a consequence cylinder pressure tends to exhibit high amplitudes and frequencies, which can lead to engine damage.This paper presents a model which allows linking 3D-CFD with a detailed chemical reaction system. Therefore a three-dimensional numerical model in OpenFOAM is formulated that includes all physical characteristics of a direct-injected, highly charged spark ignition engine. The conservation equation for mass, momentum and energy form the mathematical basis for the modeling approach. Additional equations for spray modeling and for turbulence-chemistry…
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Prediction of CO Emissions from a Gasoline Direct Injection Engine Using CHEMKIN®

University of Rostock-Nataporn Chindaprasert, Egon Hassel, Jürgen Nocke, Christoph Janssen
IAV GmbH-Matthias Schultalbers, Olaf Magnor
Published 2006-10-16 by SAE International in United States
Modern engines are intended to work at high efficiency and at the same time have low emissions. Since modern engines operate with nearly stoichiometric air/fuel mixtures to reduce nitrogen oxides, one of the most critical emissions is carbon monoxide and its prediction is therefore essential for today's engine design. The concept of the presented model is to combine the two-zone thermodynamic model and CHEMKIN software to predict the carbon monoxide emissions from a gasoline direct injection engine with good computational efficiency and low calculation time. The model calculation was divided into two parts. The first part is the two-zone model which can also predict the CO concentration for the exhaust condition by using the chemical equilibrium concentration. The second part is the kinetic model, which uses input data from the two-zone model and starts the calculation shortly before the end of combustion. The model was validated by experimental data from a gasoline direct injection 1.6 liter engine. The results show satisfactory CO-predictions.
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Investigation of the Atomization and Evaporation of Diesel Fuel and Heavy Fuel Sprays Using Optical Measurement Techniques

University of Rostock-Karlheinz Prescher, Andrej Astachow, Grit Krüger, Kai Hintze
Published 1999-03-01 by SAE International in United States
The optimization of mixture formation in diesel engines requires precise knowledge of the mechanisms of spray atomization and the correlation between injection and engine operating conditions and the parameters of the injection spray. The influence of the fuel properties will be shown considering both the temperature in the high-pressure chamber and the injection pressure as important variation parameters. A global temporally resolved visualization of the injection sprays is realized and information about the droplet size distributions in the spray are obtained by means of locally highly resolved laser-based measurement techniques. The low proportion of low-boiling components in heavy fuels is a significant cause for a deteriorated mixture formation. Higher temperature in the combustion chamber and higher injection pressure have a positive influence on the spray development as well as fuel evaporation.
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