The SAE MOBILUS platform will continue to be accessible and populated with high quality technical content during the coronavirus (COVID-19) pandemic. x

Your Selections

CNRS
Show Only

Collections

File Formats

Content Types

Dates

Sectors

Topics

Authors

Publishers

Affiliations

Events

   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Wind Tunnel Measurements of Simulated Glaciated Cloud Conditions to Evaluate Newly Developed 2D Imaging Probes

CNRS-Delphine Leroy
Artium Technologies Inc.-William D. Bachalo
Published 2019-06-10 by SAE International in United States
Instrumentation that has been used for characterization of mixed-phase and glaciated conditions in the past, like the OAP probes, are subject to errors caused by variations in diffraction on the images away from the object plane and by the discrete nature of their particle detection and sizing. Correction methods are necessary to consider their measurements adequate for high ice water content (IWC) environments judged to represent a significant safety hazard to propellers and turbofan engine operability and performance. For this reason, within the frame of EU FP7 HAIC project, instrumentation characterization and validation is considered a major element need for successful execution of flight tests campaigns. Clearly, instrumentation must be sufficiently reliable to assess the reproducibility of artificial clouds with high ice water content generated in icing tunnels. Instruments are required to measure these conditions with a sufficient level of accuracy for the purposes of the testing. Currently, there is an anticipated basic uncertainty of a factor of 2-5 when measuring clouds in-situ. This may be worse for thunderstorm core regions, because of the poorly…
This content contains downloadable datasets
Annotation ability available
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Uncertainty of the Ice Particles Median Mass Diameters Retrieved from the HAIC-HIWC Dataset: A Study of the Influence of the Mass Retrieval Method

SAE International Journal of Advances and Current Practices in Mobility

Delphine Leroy
CNRS-Pierre Coutris, Alfons Schwarzenboeck
  • Journal Article
  • 2019-01-1983
Published 2019-06-10 by SAE International in United States
In response to the ice crystal icing hazard identified twenty years ago, aviation industry, regulation authorities, and research centers joined forces into the HAIC-HIWC international collaboration launched in 2012. Two flight campaigns were conducted in the high ice water content areas of tropical mesoscale convective systems in order to characterize this environment conducive to ice crystal icing. Statistics on cloud microphysical properties, such as Ice Water Content (IWC) or Mass Median Diameter (MMD), derived from the dataset of in situ measurements are now being used to support icing certification rulemaking and anti-icing systems design (engine and air data probe) activities. This technical paper focuses on methodological aspects of the derivation of MMD. MMD are estimated from PSD and IWC using a multistep process in which the mass retrieval method is a critical step. Complementary to previous studies reporting on MMD values calculated from the HAIC-HIWC dataset, this paper deals with the uncertainty in MMD by comparing two different approaches for the retrieval of the mass-size (m-D) relationship. The analysis encompasses the data collected in the…
This content contains downloadable datasets
Annotation ability available
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Towards Stoichiometric Combustion in HCCI Engines: Effect of Ozone Seeding and Dilution

CNRS-Guillaume Dayma, Philippe Dagaut
Laboratoire Prisme-Pietro Matteo Pinazzi, Fabrice Foucher
Published 2015-09-06 by SAE International in United States
Homogeneous Charge Compression Ignition (HCCI) is generally considered as an efficient solution to reduce fuel consumption and meet the pollutant requirements of internal combustion engines. Furthermore, the HCCI combustion strategy delivers drastically reduced levels of NOx and particulate matter, and combined with a post treatment device, low levels of unburned hydrocarbons (HC) and carbon monoxide (CO) can be achieved. However, affordable and widely used three-way catalytic converters require the engine to be run under stoichiometric conditions. Running an HCCI engine under an increased equivalence ratio leads to advanced combustion phasing and an excessive in-cylinder pressure rate that can affect engine operation. The dilution effect of Exhaust Gas Recirculation (EGR) represents a way to delay ignition of the mixture and reduce excessive in-cylinder pressure gradients. However, acting exclusively on dilution in order to control HCCI combustion is problematic and could lead to misfire or unstable combustion characteristics. Recent studies demonstrated that seeding the engine intake with oxidizing chemical species is a promising strategy to achieve combustion control in HCCI engines. Among many oxidizing chemical species, ozone…
Annotation ability available
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Application of an Ozone Generator to Control the Homogeneous Charge Compression Ignition Combustion Process

CNRS-Guillaume Dayma, Philippe Dagaut
Universite D'Orleans-Fabrice Foucher, Christine Rousselle
Published 2015-09-06 by SAE International in United States
The present investigation examines a new way to control the homogeneous charge compression ignition (HCCI) process. An ozone generator was set up to seed the intake of a single-cylinder engine with low concentrations of ozone. Two kinds of gas supply were tested: an oxygen supply and an air supply; as well as two kinds of injection: a plenum injection and an injection inside one of the intake pipes. The results showed that air can easily be used and that the second injection mode is the best way to achieve an on-road application. Moreover, experiments demonstrated that each combustion parameter such as the phasing, the indicated mean effective pressure and the pollutants can be controlled by varying the capacity of the ozone generator. Then, from experimental results, two dynamic control approaches on the maximum pressure phasing were proposed. A cartography control showed that a fast control of the combustion phasing can be achieved and a closed loop control demonstrated an excellent accuracy. Finally, this investigation demonstrated that an on-road application is achievable and improvements of this…
Annotation ability available
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

The Use of RDT Nowcasting Tool for Detecting Convective Areas Associated with High Ice Water Content during HAIC/HIWC Field Campaign

CNRS-Eric Défer, Michael Faivre
ATMOSPHERE, Systèmes & Services-Sandra Turner
Published 2015-06-15 by SAE International in United States
Glaciated icing conditions potentially leading to in-service event are often encountered in the vicinity of deep convective clouds. Nowcasting of these conditions with space-borne observations would be of a great help for improving flight safety and air-traffic management but still remains challenging. In the framework of the HAIC (High Altitude Ice Crystals) project, methods to detect and track regions of high ice water content from space-based geostationary and low orbit mission are investigated.A first HAIC/HIWC field campaign has been carried out in Australia in January-March 2014 to sample meteorological conditions potentially leading to glaciated icing conditions. During the campaign, several nowcasting tools were successfully operated such as the Rapid Development Thunderstorm (RDT) product that detects the convective areas from infrared geostationary imagery. The RDT tracks clouds, identifies those that are convective, and provides a temporal and spatial description of their microphysical, morphological and dynamical properties. Comparison of in-situ measurements collected during the HAIC 2014 flights show that there is a good detection of convective cells, and most of the time, high concentration of ice water…
Annotation ability available
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Effect of Additives on Combustion Characteristics of a Natural Gas Fueled HCCI Engine

CNRS-Guillaume Dayma, Philippe Dagaut
CNRS - Université d'Orléans-Jean-Baptiste Masurier
Published 2014-10-13 by SAE International in United States
Homogeneous Charge Compression Ignition (HCCI) is among the new generation of combustion modes which can be applied to internal combustion engines. It is currently the topic of numerous studies in various fields. Due to its operating process, HCCI ensures a good efficiency, similar to that of compression ignition (CI) engines, and low particulate and nitric oxide (NOx) emissions. However, before promoting the use of this kind of engine, several challenges must be addressed, in particular controlling the combustion.Recent work showed that the combustion phasing can be controlled using low concentrations of ozone, an oxidizing chemical species. As ozone generators become increasingly compact, the integration of this kind of device in passenger cars can be considered.The present study investigates the effect of ozone on the combustion of different fuel mixtures. The engine was fuelled with various blends: a 95%methane/5%propane mixture and three different methane/hydrogen mixtures. The engine parameters and pollutant emissions were analyzed as a function of ozone seeding in several cases: by degrading the intake pressure, by degrading the intake temperature, and by varying the…
Annotation ability available
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Engine Performances and Emissions of Second-Generation Biofuels in Spark Ignition Engines: The Case of Methyl and Ethyl Valerates

CNRS-Guillaume Dayma, Philippe Dagaut
Universite D'Orleans-Christine Mounaïm-Rousselle
Published 2013-09-08 by SAE International in United States
As an alternative to second generation ethanol, valeric esters can be produced from lignocellulose through levulinic acid. While some data on these fuels are available, only few experiments have been performed to analyze their combustion characteristics under engine conditions. Using a traditional spark ignition engine converted to mono-cylinder operation, we have investigated the engine performances and emissions of methyl and ethyl valerates. This paper compares the experimental results for pure valeric esters and for blends of 20% of esters in PRF95, with PRF95 as the reference fuel. The esters propagate faster than PRF95 which requires a slight change of ignition timing to optimise the work output. However, both the performances and the emissions are not significantly changed compared to the reference. Accordingly, methyl and ethyl valerate represent very good alternatives as biofuels for SI engines. Future studies will focus on testing these esters in real application engines and performing endurance tests.
Annotation ability available
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Towards HCCI Control by Ozone Seeding

CNRS-Guillaume Dayma, Philippe Dagaut
Universite d'Orleans-Fabrice Foucher, Christine Mounaïm-Rousselle
Published 2013-09-08 by SAE International in United States
Nowadays, the main objectives in the automobile engine field are to reduce fuel consumption and pollutant emissions. HCCI engines can be a good solution to meet pollutant emission requirements and to achieve high combustion efficiency. However, before an HCCI engine is used as a conventional engine, several problems must be overcome, in particular control of the progression of combustion.Many studies have been conducted into possible control methods. A new strategy consists in using oxidizing chemical species such as ozone to seed the intake of a HCCI engine. As increasingly smaller ozonizers are now being designed, this kind of device could be integrated on a vehicle and on a HCCI engine, in order to control combustion phasing and promote the future use of this engine as a conventional engine.In the present study, experiments on a HCCI engine fuelled with iso-octane were carried out with ozone seeding in the intake. Results showed that when assisted by the addition of ozone, combustion can be enhanced and moved forward. Consequently, the use of oxidizing chemical species can be a…
Annotation ability available
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Extended Non-Destructive Testing of Composite Bonds

CNRS-Michel Boustie, Romain Ecault, Laurent Berthe
Airbus-Clemens Bockenheimer
Published 2011-10-18 by SAE International in United States
Composite materials are increasingly being used in the manufacturing of structural components in aeronautics industry. A consequent light-weight design of CFRP primary structures requires adhesive bonding as the optimum joining technique but is limited due to a lack of adequate quality assurance procedures. The successful implementation of a reliable quality assurance concept for adhesive bonding within manufacturing and in-service environments will provide the basis for increased use of lightweight composite materials for highly integrated aircraft structures thus minimizing rivet-based assembly. The expected weight saving for the fuselage airframe is remarkable and therefore the driver for research and development of key-enabling technologies.The performance of adhesive bonds mainly depends on the physico-chemical properties of adherend surfaces. Therefore, a set of advanced non-destructive testing techniques is applied and adapted to the characterization of CFRP bonded structures as well as the state of adherend surfaces before bonding within the ENCOMB-project. As a medium-scale European Consortium funded within the 7th Framework Programme, ENCOMB (Extended Non-Destructive Testing of Composite Bonds) brings together leading experts in aeronautics research and development providing advanced…
Annotation ability available
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Turbine Efficiency Estimation for Fault Detection Application

CNRS-Carlos Canudas de Wit
IFP-Riccardo Ceccarelli, Philippe Moulin
Published 2010-04-12 by SAE International in United States
In nowadays diesel engine, the turbocharger system plays a very important role in the engine functioning and any loss of the turbine efficiency can lead to driveability problems and the increment of emissions. In this paper, a VGT turbocharger fault detection system is proposed. The method is based on a physical model of the turbocharger and includes an estimation of the turbine efficiency by a nonlinear adaptive observer. A sensitivity analysis is provided in order to evaluate the impact of different sensors fault, (drift and bias), used to feed the observer, on the estimation of turbine efficiency error. By the means of this analysis a robust variable threshold is provided in order to reduce false detection alarm. Simulation results, based on co-simulation professional platform (AMEsim© and Simulink©), are provided to validate the strategy.
Annotation ability available