Automated Test Bed Research Articles

Automated modular high energy evaluation system for experimental thyristor devices

A high energy, modular, completely automated test bed with integrated data acquisition and characterization systems was successfully designed in order to perform both safe operating area as well as very high volume reliability testing on experimental silicon carbide Super Gate Turn Off (SGTO) thyristors. Although the system follows a modular design philosophy, with each functional block acting as a peripheral to a main control module and can be adapted to arbitrary power and pulse width levels, for the specific SGTO devices initially evaluated it was configured to have the device discharge variable current levels of up to 6 kA into a 0.5 Ω resistive load with a relatively square pulse fixed at 100 μs full width at half maximum delivering energy levels up to 1.8 kJ to the load.

Performance Analysis of Text Alignment Tools Using Automated Test Bed

The text alignment process is an important activity in the statistical machine translation (SMT) upon the training phase of SMT systems on huge amounts of parallel corpora. We are evaluating five of the popular text aligners and analyzing the methodologies used in each of them, then we are introducing new open source automated test bed for testing those text alig ners and generating reports called pyTester, and finally discuss our observations about the test results generated from pyTester .

Multi-zone modeling of combustion and emissions formation in DI diesel engine operating on ethanol–diesel fuel blends

A multi-zone model for calculation of the closed cycle of a direct injection (DI) diesel engine is applied for the interesting case of its operation with ethanol–diesel fuel blends, the ethanol (bio-fuel) being considered recently as a promising extender to petroleum distillates. Although there are many experimental studies, there is an apparent scarcity of theoretical models scrutinizing the formation mechanisms of combustion generated emissions when using bio-fuels. This is a two dimensional, multi-zone model with the issuing fuel jets divided into several discrete volumes, called ‘zones’, formed along and across the direction of the fuel injection. The model follows each zone, with its own time history, as the spray penetrates into the swirling air environment of the combustion chamber. Droplet evaporation and jet mixing models are used to determine the amount of fuel and entrained air in each zone available for combustion. The mass, energy and state equations are applied in each zone to provide local temperatures and cylinder pressure histories. The concentrations of the various constituents are calculated by adopting a chemical equilibrium scheme for the C–H–O–N system of eleven species considered, together with chemical rate equations for calculation of nitric oxide (NO) and a model for net soot formation. The results from the computer program, implementing the analysis, for the in cylinder pressure, exhaust NO concentration and soot density compare well with the corresponding measurements from an experimental investigation conducted on a fully automated test bed, standard ‘Hydra’, DI diesel engine located at the authors’ laboratory, which is operated with ethanol–diesel fuel blends containing 5%, 10% and 15% (by vol.) ethanol. Iso-contour plots of equivalence ratio, temperature, NO and soot inside the cylinder at various instants of time, when using these ethanol–diesel fuel blends against the diesel fuel (baseline fuel), shed light on the mechanisms underlying the combustion and pollutants formation. They reveal how the widely differing properties of ethanol in these blends, against the normal diesel fuel, affect greatly the combustion mechanism and the related emitted pollutants.

Development and application of multi-zone model for combustion and pollutants formation in direct injection diesel engine running with vegetable oil or its bio-diesel

Abstract A multi-zone model for calculation of the closed cycle of a direct injection (DI) Diesel engine is presented and applied for the interesting case of its operation with vegetable oil (cottonseed) or its derived bio-diesel (methyl ester) as fuels, which recently are considered as promising alternatives (bio-fuels) to petroleum distillates. Although there are many experimental studies, there is an apparent scarcity of theoretical models scrutinizing the formation mechanisms of combustion generated emissions when using these fuels. The model is two dimensional, multi-zone with the issuing jets (from the nozzle) divided into several discrete volumes, called ‘zones’, formed along the direction of the fuel injection and across it. The model follows each zone, with its own time history, as the spray penetrates into the swirling air environment (forming the non-burning zone) of the combustion chamber, before and after wall impingement. Droplet evaporation and jet mixing models are used to determine the amount of fuel and entrained air in each zone available for combustion. The mass, energy and state equations are applied in each zone to yield local temperatures and cylinder pressure histories. The concentrations of the various constituents are calculated by adopting a chemical equilibrium scheme for the C–H–O–N system of 11 species considered, together with the chemical rate equations for the calculation of nitric oxide (NO). A model for evaluation of soot formation and oxidation rates is included. The results from the relevant computer program for the in cylinder pressure, exhaust nitric oxide concentration (NO) and soot density are compared favorably with the corresponding measurements from an experimental investigation conducted on a fully automated test bed, standard ‘Hydra’, DI Diesel engine installed at the authors’ laboratory. Iso-contour plots of equivalence ratio, temperature, NO and soot inside the combustion chamber at various instants of time when using these fuels against Diesel fuel (baseline fuel) shed light on the mechanisms underlying the combustion and pollutants formation and reveal how the widely differing properties of these fuels, against the normal Diesel fuel, affect greatly the spray formation, combustion mechanism and the related emissions.

Validation and sensitivity analysis of a two zone Diesel engine model for combustion and emissions prediction

The present two zone model of a direct injection (DI) Diesel engine divides the cylinder contents into a non-burning zone of air and another homogeneous zone in which fuel is continuously supplied from the injector and burned with entrained air from the air zone. The growth of the fuel spray zone, which comprises a number of fuel-air conical jets equal to the injector nozzle holes, is carefully modelled by incorporating jet mixing, thus determining the amount of oxygen available for combustion. The mass, energy and state equations are applied in each of the two zones to yield local temperatures and cylinder pressure histories. The concentration of the various constituents in the exhaust gases are calculated by adopting a chemical equilibrium scheme for the C–H–O system of the 11 species considered, together with chemical rate equations for the calculation of nitric oxide (NO). A model for evaluation of the soot formation and oxidation rates is included. The theoretical results from the relevant computer program are compared very favourably with the measurements from an experimental investigation conducted on a fully automated test bed, standard “Hydra”, DI Diesel engine installed at the authors’ laboratory. In-cylinder pressure and temperature histories, nitric oxide concentration and soot density are among the interesting quantities tested for various loads and injection timings. As revealed, the model is sensitive to the selection of the constants of the fuel preparation and reaction sub-models, so that a relevant sensitivity analysis is undertaken. This leads to a better understanding of the physical mechanisms governed by these constants and also paves the way for construction of a reliable and relatively simple multi-zone model, which incorporates in each zone (packet) the philosophy of the present two zone model.

Investigation of an electrophotography based rapid prototyping technology

A method for rapid prototyping based on electrophotographic powder deposition was investigated to study its potentials and to identify design and implementation challenges. This technique is referred to here as the electrophotographic rapid prototyping (ERP). In this technique, powder is printed layer‐by‐layer in the shape of the cross‐sections of the part using electrophotography a very widely used non‐impact printing method. Each layer of powder is consolidated by fusing before the next layer of powder is printed. A fully automated test bed was constructed that consists of a printing system, fusing/heating plate, build platform that has two‐degrees of freedom as well as software that drives the system.

Development and validation of a comprehensive two-zone model for combustion and emissions formation in a DI diesel engine

A two-zone model for the calculation of the closed cycle of a direct injection (DI) diesel engine is presented. The cylinder contents are taken to comprise a non-burning zone of air and another homogeneous zone in which fuel is continuously supplied from the injector holes during injection and burned with entrained air from the air zone. The growth of the fuel spray zone, consisting of a number of fuel–air conical jets equal to the injector nozzle holes, is carefully modelled by incorporating jet mixing to determine the amount of oxygen available for combustion. Application of the mass, energy and state equations in each one of the two zones yields local temperatures and cylinder pressure histories. For calculating the concentration of constituents in the exhaust gases, a chemical equilibrium scheme is adopted for the C–H–O system of the 11 species considered, together with chemical rate equations for the calculation of nitric oxide (NO). A model for the evaluation of soot formation and oxidation rates is incorporated. A comparison is made between the theoretical results from the computer program implementing the analysis, with experimental results from a vast experimental investigation conducted on a fully automated test bed, direct injection, standard ‘Hydra’, diesel engine located at the authors' laboratory, with very good results, following a multi-parametric study of the constants incorporated in the various sub-models. Pressure indicator diagrams and plots of temperature, NO, soot density and of other interesting quantities are presented as a function of crank angle, for various loads and injection timings, elucidating the physical mechanisms governing combustion and pollutants formation. Copyright © 2003 John Wiley & Sons, Ltd.

Robotic technology integration for army ground vehicles

This paper discusses the US Army Tank Automotive Research, Development and Engineering Center's (TARDEC's) four (4) axis strategy for integration of robotics into the legacy, interim, and objective forces. At the cornerstone of this strategy is the R&D effort concentrating on autonomous perception and navigation, intelligent tactical behavior, command and control, and man-robot interface entailed in the Demo III and Robotic Follower programs. Smart Manned Systems focuses on a systems engineering approach for robotic solutions into the interim force (Vetronics Technology Testbed and Crew Integration & Automation Testbed). In the near-term, application of robotics to the legacy force will be achieved through adapting commercial automation technologies, which address military requirements. Finally, Intelligent Mobility will investigate improving intrinsic platform mobility to lessen the burden on robotic sensing performance. The ultimate goal of this strategy is to advance the robotics technology state-of-the-art to achieve off-road full autonomous operations for military systems in support of the objective force.