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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 Magdeburg-Dominique Thévenin
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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Self-Calibrating Model for Diesel Engine Simulations

University of Magdeburg-Gábor Janiga, Dominique Thévenin
Brandenburg University of Technology-Michal Pasternak, Fabian Mauss
Published 2012-04-16 by SAE International in United States
A self-calibrating model for Diesel engine simulations is presented. The overall model consists of a zero-dimensional direct injection stochastic reactor model (DI-SRM) for engine in-cylinder processes simulations and a package of optimization algorithms (OPAL) suitable for solving various optimization, automatization and search problems. In the DI-SRM, based on an extensive model parameters study, the mixing time history that affects the level of in-cylinder turbulence was selected as a main calibration parameter. As targets during calibration against the experimental data, in-cylinder pressure history and engine-out emissions, including nitrogen oxides and unburned hydrocarbons were chosen. The calibration task was solved using DI-SRM and OPAL working as an integrated tool. Within OPAL, genetic algorithms (GA) were used to determine model constants necessary for calibrating. Engine-out emissions in DI-SRM were calculated based on the reduced mechanism of n-heptane. The developed simulation method has been applied to simulate Diesel engine performance parameters at part load conditions. It has been found that with the presented approach it is possible to efficiently calibrate Diesel engine model in terms of integrated parameters such…
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Analysis of Highly Dynamic Components in the Common-Rail Injection System

University of Magdeburg-Heiner Haberland, Lothar Schulze, Helmut Tschöke
  • Technical Paper
  • 2004-05-0439
Published 2004-05-23 by Society of Automotive Engineers of Korea in South Korea
In order to meet all requirements for the diesel engine's emission and performance the injection system must deliver the exact injection quantity with the corresponding injection pattern at all operating points. To realize this it is imperative to understand the internal processes within the injection system.In the following all major functional components of the common-rail injector are going to be metrologically analyzed including the control valve, control orifice and injection nozzle. Based on this analysis simulation models for all components are created and are going to be verified individually. The model elements are combined in the injector model and are verified by measured values. The prediction accuracy of the developed injector model is excellent.

Design aspects of the adaptive wing~The elastic trailing edge and the local spoiler bump

University of Magdeburg-The. Bein, H. Hanselka
DLR-H. P. Monner, E. Breitbach
  • Technical Paper
  • 1998-11-0098
Published 1998-10-26 by Royal Aeronautical Society in United Kingdom
Market research predicts for the aircraft industry a large growth in numbers of passengers as well as in airfreight rate. Leading to an increased competition for the European aircraft industry, the efficiency of new aircraft has to be improved drastically. One approach among others is the aerodynamical optimization of the wing. The fixed wing is designed optimally only for one flight condition. This flight condition is described by the parameters altitude, mach number and aircraft weight which vary permanently during the mission of the aircraft. Therefore, the aircraft is just periodically near the chosen design point. To compensate for this major disadvantage, an "adaptive wing" for optimal adaptation and variation of the profile geometry to the actual flight conditions will be developed. Daimler-Benz Aerospace Airbus, Daimler-Benz Research and the German Aerospace Center (DLR) are working as project partners on concepts for a variable camber and a local spoiler bump. In this paper, structural concepts developed by the German Aerospace Center for both objectives will be presented. The concepts are designed under the aspect of adaptive…

Modelling and control of piezoelectric actuators

University of Magdeburg-R. Kasper
  • Technical Paper
  • 1996-25-0296
Published 1996-06-03 by ISATA - Dusseldorf Trade Fair in United Kingdom
A nonlinear mathematical model is presented that describes the dynamic behavior of piezoelectric actuators for the complete range of input voltage operating up to the natural frequency. The model is very compact and can be parameterized with little effort. On the basis of this model an efficient control concept can be designed that combines the electrical and mechanical features of the actuator in an optimal way allowing high-speed control with high energy efficiency.