Your Selections

Optics
Show Only

Collections

File Formats

Content Types

Dates

Sectors

Topics

Authors

Publishers

Affiliations

Committees

Events

Magazine

 

Optical investigation of mixture formation in a small bore DISI engine by laser induced exciplex fluorescence (LIEF)

Technische Univ. Braunschweig-Alexander Pauls, Peter Eilts
  • Technical Paper
  • 2019-24-0133
To be published on 2019-08-15 by SAE International in United States
Legislative and customer demands in terms of fuel consumption and emissions are an enormous challenge for the development of modern combustion engines. Downsizing in combination with turbocharging and direct injection is one way to increase efficiency and therefore meet the requirements. This results in a reduction of the displacement and thus the bore diameter. The application of direct injection with small cylinder dimensions increases the probability of the interaction of liquid fuel with the cylinder walls, which may result in disadvantages concerning especially particulate emissions. This leads to the question which bore diameter is feasible without drawbacks concerning emissions as a result of wall wetting. The emerging trends towards long-stroke engine design and hybridization make the use of small bore diameters in future gasoline engines a realistic scenario. In the previous project “GDI Boundary Bore” the feasibility of an SI engine with direct injection and small bore diameter was shown by the analyses of two different cylinder head concepts (3V and 4V). For the acquirement of deeper understanding of the mixture formation in such engines…
 

Optical evaluation of directly injected methane using a newly developed highly repetitive laser diagnostics system

Bayreuth Engine Research Center-Mirko Geiger, Lukas Schroeder, Christian Zoellner, Dieter Brueggemann
InnoLas Laser GmbH-Matthias Resch
  • Technical Paper
  • 2019-24-0134
To be published on 2019-08-15 by SAE International in United States
New certification procedures like WLTP and RDE, as well as more stringent emission regulations in general, demand for further improvements in engine research and development. In order to meet the challenges of reducing pollutants while maintaining high performance and high efficiency many different approaches are discussed. Beside various concepts for new combustion strategies and alternative fuels, gaining detailed knowledge about the ongoing processes inside engines and combustion chambers during the different operation modes is of major importance. With their influence on combustion and emission formation, fuel injection and mixture formation are playing an important role for further improvements in modern propulsion systems. With the help of optical measurement systems based on laser induced (exciplex) fluorescence (LIF/ LIEF), an advanced understanding of these mechanisms can be obtained. However, additional challenges arise when it comes to analyzing transient engine operation and cyclic fluctuations as well as rating their contribution to the formation of emissions. This study contains the evaluations of the injection and mixture formation inside a rapid compression machine (RCM) with directly injected methane. Equipped with…
 
new

Guidelines for Harness Critical Clamp Locator Marker Installation on Electrical Cable Assemblies

AE-8A Elec Wiring and Fiber Optic Interconnect Sys Install
  • Aerospace Standard
  • ARP5614
  • Current
Published 2019-06-11 by SAE International in United States
This ARP specifies the recommended methods of marking electrical wiring and harnesses to aid in the positioning/routing of electrical wiring, harnesses and cable assemblies.
Datasets icon
Annotation icon
 
new

SLD and Ice Crystal Discrimination with the Optical Ice Detector

Collins Aerospace-Kaare J. Anderson, Mark D. Ray
Published 2019-06-10 by SAE International in United States
In response to new safety regulations regarding aircraft icing, Collins Aerospace has developed and tested an Optical Ice Detector (OID) capable of discriminating among icing conditions appropriate to Appendix C and Appendix O of 14 CFR Part 25 and Appendix D of Part 33. The OID is a short-range, polarimetric lidar that samples the airstream up to ten meters beyond the skin of the aircraft. The intensity and extinction of the backscatter light correlate with bulk properties of the cloud, such as water content and phase. Backscatter scintillation (combined with the outside air temperature from another probe) signals the presence of supercooled large droplets (SLD) within the cloud-a capability incorporated into the OID to meet the requirements of Appendix O.Recent laboratory and flight tests of the Optical Ice Detector have confirmed the efficacy of the OID to discriminate among the various icing conditions. Drizzle-sized droplets, mixed with a small droplet cloud in the Collins Cloud Chamber, appear as scintillations in the lidar signal when it is processed pulse-by-pulse. Averaging the signal over multiple pulses, causes…
Annotation icon
 
new

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

Artium Technologies Inc.-William D. Bachalo
CIRA, Italian Aerospace Research Centre-Biagio M. Esposito
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…
Datasets icon
Annotation icon
 
new

Process Regulations and Mechanism of WEDM of Combustor Material

SAE International Journal of Aerospace

National Institute of Technology, Kurukshetra, India-Bhupinder Singh, Joy Prakash Misra
  • Journal Article
  • 01-12-01-0004
Published 2019-06-07 by SAE International in United States
This study discusses the experimental investigation on WEDM of combustor material (i.e., nimonic 263). Experimentation has been executed by varying pulse-on time (Ton), pulse-off time (Toff), peak current (Ip), and spark gap voltage (Sv). Material removal rate (MRR), surface roughness (SR), and wire wear rate (WWR) are employed as process performance characteristics. Experiments are designed as per the box-Behnken design technique. Parametric optimization has also been performed using response surface methodology. Besides this, field-emission scanning electron microscope (FE-SEM) and an optical microscope are utilized to characterize WEDMed and worn-out wire surfaces. It is observed that both surfaces contain micro-cracks, craters, spherical droplets, and a lump of debris. Furthermore, the mechanism of recast layer formation has been critically evaluated to apprehend a better understanding of the technique. The key features of the experimental procedure are also highlighted.
Datasets icon
Annotation icon
 
new

A Non-Contact Technique for Vibration Measurement of Automotive Structures

Kettering University-Vanshaj Srivastava, Javad Baqersad
Published 2019-06-05 by SAE International in United States
The automotive and aerospace industries are increasingly using the light-weight material to improve the vehicle performance. However, using light-weight material can increase the airborne and structure-borne noise. A special attention needs to be paid in designing the structures and measuring their dynamics. Conventionally, the structure is excited using an impulse hammer or a mechanical shaker and the response is measured using uniaxial or multi-axial accelerometers to obtain the dynamics of the structure. However, using contact-based transducers can mass load the structure and provide data at a few discrete points. Hence, obtaining the true dynamics of the structure conventionally can be challenging. In the past few years, stereo-photogrammetry and three-dimensional digital image correlation have received special attention in collecting operating data for structural analysis. These non-contact optical techniques provide a wealth of distributed data over the entire structure. However, the stereo camera system is limited by its field of view of the cameras and can only measure the response on the parts of the structure that cameras have the line of sight. Therefore, a single pair…
Annotation icon
 
new

All-Fiber, Optically Controlled Optical Switch

  • Magazine Article
  • TBMG-34622
Published 2019-06-01 by Tech Briefs Media Group in United States

An optical switch is a device where information-bearing light may be directed to one of several outputs. Prior art optical switches have mainly been integrated optical waveguide structures such as titanium-diffused (Ti) waveguides in lithium-niobate (LiNbO3) or gallium-arsenide (GaAs) structures, or other compound semiconductors.

 
new

Infrared Light-Focusing Platform

  • Magazine Article
  • TBMG-34630
Published 2019-06-01 by Tech Briefs Media Group in United States

Researchers have integrated two technologies widely used in applications such as optical communications, bio-imaging, and Light Detection and Ranging (LiDAR) systems to create a new infrared light-focusing system that combines the best features of both technologies while reducing the size of the optical system.

 
new

Programming Light on a Chip

  • Magazine Article
  • TBMG-34606
Published 2019-06-01 by Tech Briefs Media Group in United States

Microwave signals are ubiquitous in wireless communications but interact too weakly with photons. A technique was developed to fabricate high-performance optical microstructures using lithium niobate, a material with powerful electro-optic properties. The new integrated photonics platform can store light and electrically control its frequency (or color) in an integrated circuit. The platform draws inspiration from atomic systems and could have a wide range of applications including photonic quantum information processing, optical signal processing, and microwave photonics.