scholarly journals The Gasoline Diesel

2012 ◽  
Vol 134 (09) ◽  
pp. 38-41 ◽  
Author(s):  
Steve Ciatti
Keyword(s):  
Fuel Economy ◽  
Diesel Engines ◽  
National Laboratory ◽  
Argonne National Laboratory ◽  
Spark Ignition ◽  
Reliable Operation ◽  
Excellent Performance ◽  
Research Teams ◽  
Gasoline Engines ◽  
Engine Efficiency

This article evaluates engine efficiency as a step towards improving fuel economy and emissions performance. Diesel engines tend to be very efficient; however, they have an emissions problem. They require complex and expensive equipment to meet pollution mandates. Spark ignition gasoline engines, on the other hand, do a much better job with emissions, but they are inherently less efficient. Thus, the research team at Argonne National Laboratory has decided to look for ways to combine the best characteristics of both. This new system is more like traditional diesel combustion than spark ignition, but uses a gasoline-like fuel and an innovative approach to combustion to minimize emissions. Diesel engines tend to run lean, meaning there is more oxygen in the mix than fuel, which reduces in-cylinder average temperatures. Research shows that gasoline spark engines have fatal efficiency flaws but comply easily and relatively inexpensively with emission requirements. Diesels are more efficient, but carry a heavy penalty for emission compliance. Different research teams’ challenge is to ensure robust, reliable operation during transient operation. The new system’s torque profile is essentially the same as that of a conventional diesel, and it provides excellent performance in the powerband where most people drive.

Numerical study of auto-ignition propagation modes in toluene reference fuel–air mixtures: Toward a better understanding of abnormal combustion in spark-ignition engines

2018 ◽  
Vol 20 (7) ◽  
pp. 734-745 ◽  
Author(s):  
Anthony Robert ◽  
Jean-Marc Zaccardi ◽  
Cécilia Dul ◽  
Ahmed Guerouani ◽  
Jordan Rudloff
Keyword(s):  
Numerical Study ◽  
Hot Spot ◽  
Lawrence Livermore National Laboratory ◽  
National Laboratory ◽  
Spark Ignition ◽  
Propagation Mode ◽  
Spark Ignition Engines ◽  
Gasoline Engines ◽  
Auto Ignition ◽  
Thermodynamic Conditions

Two main abnormal combustions are observed in spark-ignition engines: knock and low-speed pre-ignition. Controlling these abnormal processes requires understanding how auto-ignition is triggered at the “hot spot” but also how it propagates inside the combustion chamber. The original theory regarding the auto-ignition propagation modes was defined by Zeldovich and developed by Bradley who highlighted different modes by considering various hot spot characteristics and thermodynamic conditions around the hot spot. Two dimensionless parameters ( ε, ξ) were then defined to classify these modes and a so-called detonation peninsula was obtained for H2–CO–air mixtures. Similar simulations as those performed by Bradley et al. are undertaken to check the relevancy of the original detonation peninsula when considering realistic fuels used in modern gasoline engines. First, chemical kinetics calculations in homogeneous reactor are performed to determine the auto-ignition delay time τi, and the excitation time τe of E10–air mixtures in various conditions. These calculations are performed for a Research Octane Number (RON 95) toluene reference fuel surrogate with 42.8% isooctane, 13.7% n-heptane, 43.5% toluene, and using the Lawrence Livermore National Laboratory (LLNL) kinetic mechanism considering 1388 species and 5935 reactions. Results point out that H2–CO–air mixtures are much more reactive than E10–air mixtures featuring much lower excitation times τe. The resulting maximal hot spot reactivity ε is thus limited which also restrains the use of the detonation peninsula for the analysis of practical occurrences of auto-ignition in gasoline engines. The tabulated ( τi, τe) values are then used to perform one-dimensional Large Eddy Simulations (LES) of auto-ignition propagation considering different hot spots and thermodynamic conditions around them. The detailed analysis of the coupling conditions between the reaction and pressure waves shows thus that the different propagation modes can appear with gasoline, and that the original detonation peninsula can be reproduced, confirming for the first time that the propagation mode can be well defined by the two non-dimensional parameters for more realistic fuels.

Local Measurements in Cavitating Flow by Ultra-Fast X-Ray Imaging

2009 ◽  
Author(s):  
O. Coutier-Delgosha ◽  
A. Vabre ◽  
M. Hocevar ◽  
R. Delion ◽  
A. Dazin ◽  
...  
Keyword(s):  
National Laboratory ◽  
Argonne National Laboratory ◽  
Velocity Fields ◽  
Cavitating Flow ◽  
Research Teams ◽  
X Ray ◽  
X Ray Imaging ◽  
Local Measurements ◽  
Velocity Pressure ◽  
Photon Source

The present paper presents an experimental method to measure velocity fields in a cavitating flow. Dynamics of the liquid phase and of the bubbles are both investigated. The measurements are based on ultra fast X-ray imaging performed at the APS (Advanced Photon Source) of the Argonne National Laboratory. This is collaboration between research teams devoted to fluid mechanics (LML laboratory, Laboratory for water and turbine machines) and experts in X-ray imaging (French atomic commission, Argonne National Laboratory). The experimental device consists of a millimetric Venturi test section associated with a transportable hydraulic loop. Various configurations of velocity, pressure, and temperature have been investigated. This first paper focuses on the experimental equipment and process, and also the description of the image processing which is performed to analyze the results and obtain the velocity fields of both phases within the cavitating areas. Promising preliminary results are also presented.

Use of Ethanol Based Oxygenates for Smoke Reduction in C.I. Engines

2005 ◽  
Author(s):  
Dhananjay B. Zodpe ◽  
Nishikant V. Deshpande
Keyword(s):  
Experimental Investigation ◽  
Fuel Economy ◽  
Diesel Engines ◽  
Thermal Efficiency ◽  
Substantial Reduction ◽  
Brake Thermal Efficiency ◽  
Gasoline Engines ◽  
Brake Power ◽  
Smoke Density ◽  
Harmful Effects

Diesel Engines have better fuel economy compared to gasoline engines. Society is now aware of various harmful effects of pollution and various researchers are trying to use fuel reformulation method to meet the forthcoming stringent air pollution norms for the diesel engines. This paper presents an experimental investigation on use of three different low price ethanol based oxygenate-diesel blends (oxygenate 4, 8 and 12% in blend) as an oxygen enriched fuel in diesel engine and its effect on brake thermal efficiency, smoke density and emissions of CO, HC, NOx etc is studied. It was observed that there is substantial reduction in the smoke density of exhaust gases and the observed reduction was found proportional to the mass of oxygen present in the blend. Marginal increase in NOx and brake thermal efficiency was observed and there was no significant change in the brake power of the engine.

scholarly journals An overview of cold start emissions from direct injection spark-ignition and compression ignition engines of light duty vehicles at low ambient temperatures

2013 ◽  
Vol 154 (3) ◽  
pp. 96-103
Author(s):  
Piotr BIELACZYC ◽  
Andrzej SZCZOTKA ◽  
Joseph WOODBURN
Keyword(s):  
Ambient Temperature ◽  
Diesel Engines ◽  
Direct Injection ◽  
Cold Start ◽  
Spark Ignition ◽  
Driving Cycle ◽  
Special Focus ◽  
Passenger Cars ◽  
Gasoline Engines ◽  
Ambient Temperatures

Spark-ignition (SI) engines are highly susceptible to excess emissions when started at low ambient temperatures, a phenomenon which has been widely discussed in the literature. Direct injection diesel engines feature a markedly different fuelling and combustion strategy, and as such their emissions behaviour is somewhat different from gasoline engines. The excess emissions of diesel engines at low ambient temperatures should also differ. The aim of this study was to compare excess emissions of gaseous and solid pollutants over a legislative driving cycle (the New European Driving Cycle, NEDC) following cold start at a low ambient temperature for both engine types. This paper examines emissions at low ambient temperatures with a special focus on cold start; emissions are also compared to start-up at a higher ambient temperature (24 °C). The causes of excess emissions andfuel consumption are briefly discussed. A series of tests were performed on European Euro 5 passenger cars on a chassis dynamometer within an advanced climate-controlled test laboratory at BOSMAL Automotive Research and Development Institute, Poland. Emissions data obtained over the Urban Driving Cycle by testing at 24 °C and at -7 °C, are presentedfor a selection ofmodern Euro 5 gasoline and diesel vehicles representative of the European passenger carfleet. A full modal emissions analysis was also conducted at 24 °C and at -7 °C over the NEDC. Emissions andfuel consumption were substantially higher at -7 °C than at 24 °C.

scholarly journals The Advanced Photon Source: Performance and Results from Early Operation

1998 ◽  
Vol 5 (3) ◽  
pp. 155-157 ◽  
Author(s):  
David E. Moncton
Keyword(s):  
National Laboratory ◽  
Argonne National Laboratory ◽  
Early Operation ◽  
Research Teams ◽  
Undulator Radiation ◽  
Design Specifications ◽  
Scientific Results ◽  
Photon Source ◽  
Future Plans

The Advanced Photon Source at Argonne National Laboratory is now providing researchers with high-brilliance undulator radiation from below 1 keV to beyond 100 keV. All technical facilities and components are operational and have met design specifications. Fourteen research teams, with responsibility for 40 beamlines on the APS experiment hall floor, are currently installing beamline instrumentation or actively taking data. An overview is presented for the first operational year of the Advanced Photon Source. Emphasis is on the performance of accelerators and insertion devices, as well as early scientific results and future plans.

Electron and ion irradiation-induced dissolution of mechanical twins in the intermetalic U3Si: An in situ HVEM study

1989 ◽  
Vol 47 ◽  
pp. 652-653
Author(s):  
Charles W. Allen ◽  
Robert C. Birtcher
Keyword(s):  
Elevated Temperatures ◽  
Ion Irradiation ◽  
Ion Beam ◽  
National Laboratory ◽  
Argonne National Laboratory ◽  
Heavy Ion ◽  
High Energy ◽  
Mechanical Twinning ◽  
In Situ Experiments

The uranium silicides, including U3Si, are under study as candidate low enrichment nuclear fuels. Ion beam simulations of the in-reactor behavior of such materials are performed because a similar damage structure can be produced in hours by energetic heavy ions which requires years in actual reactor tests. This contribution treats one aspect of the microstructural behavior of U3Si under high energy electron irradiation and low dose energetic heavy ion irradiation and is based on in situ experiments, performed at the HVEM-Tandem User Facility at Argonne National Laboratory. This Facility interfaces a 2 MV Tandem ion accelerator and a 0.6 MV ion implanter to a 1.2 MeV AEI high voltage electron microscope, which allows a wide variety of in situ ion beam experiments to be performed with simultaneous irradiation and electron microscopy or diffraction.At elevated temperatures, U3Si exhibits the ordered AuCu3 structure. On cooling below 1058 K, the intermetallic transforms, evidently martensitically, to a body-centered tetragonal structure (alternatively, the structure may be described as face-centered tetragonal, which would be fcc except for a 1 pet tetragonal distortion). Mechanical twinning accompanies the transformation; however, diferences between electron diffraction patterns from twinned and non-twinned martensite plates could not be distinguished.

Environmental cell studies of deformation and fracture

1990 ◽  
Vol 48 (4) ◽  
pp. 516-517
Author(s):  
H. K. Birnbaum ◽  
I. M. Robertson
Keyword(s):  
National Laboratory ◽  
Argonne National Laboratory ◽  
Damage Threshold ◽  
Chromatic Aberration ◽  
Good Choice ◽  
Point Of View ◽  
Deformation And Fracture ◽  
Environmental Cell ◽  
Gas Molecules ◽  
The University

Studies of the effects of hydrogen environments on the deformation and fracture of fcc, bcc and hep metals and alloys have been carried out in a TEM environmental cell. The initial experiments were performed in the environmental cell of the HVEM facility at Argonne National Laboratory. More recently, a dedicated environmental cell facility has been constructed at the University of Illinois using a JEOL 4000EX and has been used for these studies. In the present paper we will describe the general design features of the JEOL environmental cell and some of the observations we have made on hydrogen effects on deformation and fracture.The JEOL environmental cell is designed to operate at 400 keV and below; in part because of the available accelerating voltage of the microscope and in part because the damage threshold of most materials is below 400 keV. The gas pressure at which chromatic aberration due to electron scattering from the gas molecules becomes excessive does not increase rapidly with with accelerating voltage making 400 keV a good choice from that point of view as well. A series of apertures were placed above and below the cell to control the pressures in various parts of the column.

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