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Optical Spray Investigations on OME3-5 in a Constant Volume High Pressure Chamber

RWTH Aachen Univ.-Christian Honecker, Marcel Neumann, Stefan Pischinger
FEV Europe GmbH-Sandra Glueck, Markus Schoenen
Published 2019-10-07 by SAE International in United States
Oxygenated fuels such as polyoxymethylene dimethyl ethers (OME) offer a chance to significantly decrease emissions while switching to renewable fuels. However, compared to conventional diesel fuel, they have lower heating values and different evaporation behaviors which lead to differences in spray, mixture formation as well as ignition delay. In order to determine the mixture formation characteristics and the combustion behavior of neat OME3-5, optical investigations have been carried out in a high-pressure-chamber using shadowgraphy, mie-scatterlight and OH-radiation recordings. Liquid penetration length, gaseous penetration length, lift off length, spray cone angle and ignition delay have been determined and compared to those measured with diesel-fuel over a variety of pressures, temperatures, rail pressures and injection durations. Liquid penetration lengths for OME3-5-sprays were found to be shorter than that of diesel-fuel analogues, while lift-off-lengths were generally observed to be longer for OME3-5, resulting in longer gaseous mixing lengths. As the cetane numbers suggested, ignition delay was found to be shorter for OME3-5. Spray cone angles were reduced at low temperature and wider at high temperature, while gaseous penetration…
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Experimental and Numerical Investigation of the Maximum Pressure Rise Rate for an LTC Concept in a Single Cylinder CI Engine

RWTH Aachen Univ.-Metin Korkmaz, Raghavan Lakshmanan, Tobias Falkenstein, Joachim Beeckmann, Heinz Pitsch
  • Technical Paper
  • 2019-24-0023
Published 2019-09-09 by SAE International in United States
In the foreseeable future, the transportation sector will continue to rely on internal combustion engines. Therefore, reduction of engine-out emissions and increase in engine efficiency are important goals to meet future legislative regulations and restricted fuel resources. One viable option, which provides lower peak temperatures and increased mixture homogeneity and thus simultaneously reduces nitric oxide as well as soot, is a low-temperature combustion (LTC) concept. However, this might result in an increase of unburnt hydrocarbon, carbon monoxide, and combustion noise due to early combustion phasing and lower engine efficiency. Various studies show that these drawbacks can be compensated by advanced injection strategies, e.g. by employing multiple injections.The aim of this work is to identify the optimum injection strategy, which enables a wide range of engine operating points in LTC mode with reduced engine-out emissions. To achieve this goal, experiments with variations in the maximum pressure rise rate, injection pressure, intake pressure, and the EGR-rate are carried out and analyzed. Numerical investigation is carried out by three dimensional (3D) computational fluid dynamics (CFD) simulations in CONVERGE…
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Metric-based Evaluation of Powertrain Software Architecture

SAE International Journal of Passenger Cars - Electronic and Electrical Systems

RWTH Aachen Univ.-Hariharan Venkitachalam, Christian Granrath
FEV GmbH-Johannes Richenhagen
  • Journal Article
  • 2017-01-1615
Published 2017-03-28 by SAE International in United States
Ensuring software quality is one of the key challenges associated with the development of automotive embedded systems. Software architecture plays a pivotal role in realizing functional and non-functional requirements for automotive embedded systems. Software architecture is a work-product of the early stages of software development. The design errors introduced at the early stages of development will increase cost of rework. Hence, an early evaluation of software architecture is important.PERSIST (Powertrain control architecture Enabling Reusable Software development for Intelligent System Tailoring) is a model-based software product line approach which focuses on cross-project standardization of powertrain software. The product line is characterized by common design guidelines and adherence to industry standards like ISO 25010, AUTOSAR and ISO 26262. This paper shows a systematic approach to ensure objective, early and repeated analysis of software architecture for the PERSIST product line using metrics. The systematic approach for architecture metrics involves the definition, implementation, measurement and, evaluation of the metrics for hybrid control unit software. With a new approach of architecture-driven development, this paper demonstrates how an early evaluation of…
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Metric-based Evaluation of Software Architecture for an Engine Management System

SAE International Journal of Engines

RWTH Aachen Univ.-Hariharan Venkitachalam
FEV GmbH-Johannes Richenhagen
  • Journal Article
  • 2016-01-0037
Published 2016-04-05 by SAE International in United States
Powertrain software development for series production faces multifaceted challenges related to high functional complexity, high quality standards, reduced time to market and high development costs. Software architecture tackles the above mentioned challenges by breaking down the complexity of application software into modular components. Hence, design errors introduced during that phase cause significant cost and time deviations. Early and repeated analysis of new and modified architecture artifacts is required to detect design errors and the impact of the subsequent changes in the software architecture.Engine management software has a high degree of functional complexity and large number of system variants depending upon market requirements. This paper deals with the methods to perform automated evaluation of Renault’s EMS 2012 Engine Management Software in a Continuous Integration Framework. The adopted approach enables frontloading of development effort, avoids quality risks at a later stage of development and reduces time and cost for series software development.
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2-Butanone Laminar Burning Velocities - Experimental and Kinetic Modelling Study

RWTH Aachen Univ.-Joachim Beeckmann, Raik Hesse, Liming Cai, Heinz Pitsch, Alexander Heufer
Tsinghua Univ.-Yanmei Yang
Published 2015-09-01 by SAE International in United States
2-Butanone (C4H8O) is a promising alternative fuel candidate as a pure as well as a blend component for substitution in standard gasoline fuels. It can be produced by the dehydrogenation of 2-butanol. To describe 2-butanone's basic combustion behaviour, it is important to investigate key physical properties such as the laminar burning velocity. The laminar burning velocity serves on the one hand side as a parameter to validate detailed chemical kinetic models. On the other hand, especially for engine simulations, various combustion models have been introduced, which rely on the laminar burning velocity as the physical quantity describing the progress of chemical reactions, diffusion, and heat conduction. Hence, well validated models for the prediction of laminar burning velocities are needed. New experimental laminar burning velocity data, acquired in a high pressure spherical combustion vessel, are presented for 1 atm and 5 bar at temperatures of 373 K and 423 K. An already existing mechanism, thoroughly validated with shock tube and rapid compression machine data, is compared against the new experimental data. It was found that the…
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The Oxidation Potential Number: An Index to Evaluate Inherent Soot Reduction in D.I. Diesel Spray Plumes

SAE International Journal of Engines

RWTH Aachen Univ.-Barbara Graziano, Benedikt Heuser, Florian Kremer, Stefan Pischinger
FEV GmbH-Hans Rohs
  • Journal Article
  • 2015-01-1934
Published 2015-09-01 by SAE International in United States
A new index to evaluate the inherent soot reduction in a diesel-like spray plume is proposed in this study. The index is named “Oxidation Potential Number” and was derived with the help of a computational fluid dynamics (CFD) software. C8 - C16 n-alkanes, 1-alcohols and di-n-ethers were studied with the help of this index over four part load engine operating conditions, representative of a C-class diesel vehicle. The CFD modelling results have shown that C8 molecules feature a higher potentiality to reduce the soot. Thus, C8 molecules were tested in a single cylinder diesel engine over the same operating conditions. In conclusion, the proposed index is compared with the soot engine out emission.
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Mixture-Formation Analysis by PLIF in an HSDI Diesel Engine Using C8-Oxygenates as the Fuel

SAE International Journal of Fuels and Lubricants

RWTH Aachen Univ.-Thomas Huelser, Daniel Klein, Benedikt Heuser, Thorsten Brands, Christian Schulz, Gerd Grunefeld, Stefan Pischinger
  • Journal Article
  • 2015-01-0960
Published 2015-04-14 by SAE International in United States
With increasing interest in new biofuel candidates, 1-octanol and di-n-butylether (DNBE) were presented in recent studies. Although these molecular species are isomers, their properties are substantially different. In contrast to DNBE, 1-octanol is almost a gasoline-type fuel in terms of its auto-ignition quality. Thus, there are problems associated with engine start-up for neat 1-octanol. In order to find a suitable glow-plug position, mixture formation is studied in the cylinder under almost idle operating conditions in the present work. This is conducted by planar laser-induced fluorescence in a high-speed direct-injection optical diesel engine.The investigated C8-oxygenates are also significantly different in terms of their evaporation characteristics. Thus, in-cylinder mixture formation of these two species is compared in this work, allowing conclusions on combustion behavior and exhaust emissions. Fuel injection strategy (single and split injection) and in-cylinder air swirl are varied.Results show that the fuel vapor remains in the peripheral region of the bowl volume near top dead center for 1-octanol, i.e., the region close to the cylinder axis is nearly vapor free. Thus, the peripheral region would…
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ERRATUM: On the Potential of Oxygenated Fuels as an Additional Degree of Freedom in the Mixture Formation in Direct Injection Diesel Engines

SAE International Journal of Fuels and Lubricants

RWTH Aachen Univ.-Barbara Graziano, Stefan Pischinger
Vka Rwth-Florian Kremer
  • Journal Article
  • 2015-01-0890.01
Published 2015-04-14 by SAE International in United States
The original Equation 3 found at the bottom of page 64 was erroneous.
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Nitric Oxide Measurements in the Core of Diesel Jets Using a Biofuel Blend

SAE International Journal of Materials and Manufacturing

RWTH Aachen Univ.-Christian Schulz, Tamara Ottenwaelder, Thomas Raffius, Thorsten Brands, Thomas Huelser, Gerd Grunefeld, Stefan Pischinger
  • Journal Article
  • 2015-01-0597
Published 2015-04-14 by SAE International in United States
Maintaining low NOx emissions over the operating range of diesel engines continues to be a major issue. However, optical measurements of nitric oxide (NO) are lacking particularly in the core of diesel jets, i.e. in the region of premixed combustion close to the spray axis. This is basically caused by severe attenuation of both the laser light and fluorescent emission in laser-induced fluorescence (LIF) applications. Light extinction is reduced by keeping absorption path lengths relatively short in this work, by investigating diesel jets in a combustion vessel instead of an engine. Furthermore, the NO-detection threshold is improved by conducting 1-d line measurements instead of 2-d imaging. The NO-LIF data are corrected for light attenuation by combined LIF and spontaneous Raman scattering. The quantified maximum light attenuation is significantly lower than in comparable previous works, and its wavelength dependence is surprisingly weak.Thereby, NO is reliably detected in the jet core. It can be attributed to premixed combustion.
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Modelling a Gasoline Compression Ignition (GCI) Engine Concept

RWTH Aachen Univ.-Kai Deppenkemper, Barbara Graziano
Concawe-Roger F. Cracknell, Javier Ariztegui, Thomas Dubois, Heather Hamje, Leonardo Pellegrini, David Rickeard, Kenneth D. Rose
Published 2014-04-01 by SAE International in United States
Future engines and vehicles will be required to reduce both regulated and CO2 emissions. To achieve this performance, they will be configured with advanced hardware and engine control technology that will enable their operation on a broader range of fuel properties than today.Previous work has shown that an advanced compression ignition bench engine can operate successfully on a European market gasoline over a range of speed/load conditions while achieving diesel-like engine efficiency and acceptable regulated emissions and noise levels. Stable Gasoline CI (GCI) combustion using a European market gasoline was achieved at high to medium engine loads but combustion at lower loads was very sensitive to EGR rates, leading to longer ignition delays and a steep cylinder pressure rise. In general, the simultaneous optimisation of engine-out emissions and combustion noise was a considerable challenge and the engine could not be operated successfully at lower load conditions without an unrealistic amount of boost pressure.To identify ways to improve the lower load performance of a GCI engine concept, Computational Fluid Dynamics and KIVA simulations have now been…
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