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Technical Paper

Recent Performance Testing of the TecoJet Post-Combustion DeNOx Technology for Diesel Engines

1999-10-25
1999-01-3684
Research in the application of nonthermal plasma technology to remove NOx from combustion flue gas is dominated by the oxidation of NO to NO2 and HNO3 (nitric acid), undesirable end products for mobile engine applications. An alternative approach is to react the NO with atomic nitrogen injected into the gas stream to reduce the NO into nitrogen and oxygen. The atomic nitrogen is generated by flowing nitrogen through multiple electrically excited, high-speed jet nozzles. The technology functions well in the sooty and wet conditions characteristic of diesel engines. A prototype system has been built and successfully demonstrated on a diesel engine exhaust slipstream at Caterpillar Inc.
Technical Paper

A Research in the Cause of Simultaneous Reduction of NOx • SFC on HONDA CVCC SI Engine

2000-06-19
2000-01-1938
(1) Through the accumulation of many researches during 1974∼94 done by the authors [8∼12,15], as like temperature measurement or the calculation of it by normal flame propagation model, it was clarified the difficulty of explanation for the captioned theme shown in the title by the conventional past concept. (2) To conquer these issued problems a new hypothesis in which the burned gas jet from pre-chamber has mixed with premixed gas in the main-chamber and acted as same as internal EGR was proposed. (3) The calculated result of this hypothesis coincided qualitatively and quantitatively with the measured flame temperature and others that the appropriateness of this was verified. (4) The result of the state in combustion at A/F=18 has been in 7% of low oxygen concentration, 2350°K of high temperature and strong turbulent condition. (5) This paper suggests a new guideline for the target to lower NOx, lower fuel consumption by low oxygen, high temperature and strong turbulent combustion.
Technical Paper

Understanding Diesel Lubricity

2000-06-19
2000-01-1918
Diesel fuel injection pumps are lubricated primarily by the fuel itself. Traditionally, fuel viscosity was used as a rough indicator of a fuel's ability to provide wear protection, but since the advent of low sulphur diesel, even some fuels of higher viscosity have been found capable of producing wear. This paper provides further insights into the main contributors to diesel fuel lubricity, their source and the impact of refinery processing. The most effective way to monitor lubricity is also considered. We have found that diesel lubricity is largely provided by trace levels of naturally occurring polar compounds which form a protective layer on the metal surface. Typical sulphur compounds do not confer this wear protection themselves rather it is the nitrogen and oxygen containing hetero-compounds that are most important. A complex mixture of polar compounds is found in diesel and some are more active than others.
Technical Paper

Automatic Reduction of Detailed Chemical Reaction Mechanisms for Autoignition Under SI Engine Conditions

2000-06-19
2000-01-1895
A method for automatic reduction of detailed reaction mechanisms using simultaneous sensitivity, reaction flow and lifetime analysis has been developed and applied to a two-zone model of an SI engine fuelled with Primary Reference Fuel (PRF). Species which are less relevant for the occurrence of autoignition in the end gas are declared redundant. They are identified and eliminated for different pre-set minimum levels of reaction flow and sensitivity. The resulting skeletal mechanism is valid in the ranges of initial and boundary values for which the analyses have been performed. A measure of species lifetime is calculated from the chemical source terms, and the species with the lifetime shorter than and mass-fraction less than specified limits are selected for removal.
Technical Paper

Simulation and Visualization of Some Processes Concerning Gases Transport Properties and Gaseous Fuel Combustion, Starting from the Molecular Collision Theory

2000-03-06
2000-01-1080
Starting from the molecular collision theory, the goals of this study are the simulation and visualization of some processes related to gases transport properties and gaseous fuel combustion, like: formation of Maxwell distribution function, diffusion, thermal diffusion, heat conductivity, heat transfer to the walls, spark ignition, autoignition, wall ignition, laminar flame propagation and two wall quenching. The simulation program replaces the molecules with a certain number of spheres (100-2700). Each specie is simulated with a determined type of sphere characterized by mass, speed, diameter and a specific color for the identification on the screen. The spheres moves inside a two-dimensional space. The collisions between spheres are elastic. The activation energy condition must be achieved during a collision involving two molecules in order to have chemical reaction.
Technical Paper

Optimal Operation of a Combined NOx/Oxygen Zirconia Sensor Under Lean Burn Conditions

2000-03-06
2000-01-1204
This article describes the development and tests of a combined NOx/oxygen Zirconia sensor. To achieve accurate NOx and oxygen measurements under lean-burn conditions, preliminary model scale experiments with a premixed methane-air burner are carried out with current production oxygen sensors as well as with our own oxygen probe. It is found from these tests that accurate oxygen sensing requires sensor operating temperatures much lower than usually set, about 600°C. Moreover, this temperature is a good compromise for NOx sensitivity and time response of the sensor. Accordingly, a new NOx/O2 sensor has been designed and prototyped. Held in a spark plug type housing, it simultaneously monitors the NOx and oxygen content of the exhaust gas. Over the wide 02 range of interest, model scale tests of the sensor with burnt gases have shown promising agreement with laboratory analysers.
Technical Paper

A Study of a Fast Light-Off Planar Oxygen Sensor Application for Exhaust Emissions Reduction

2000-03-06
2000-01-0888
It is well known that hydrocarbon reduction during a cold start is a major issue in achieving ultra low emissions standards. This paper describes one of the possible approaches for reducing the cold-start hydrocarbon emissions by using a fast “light-off” planar oxygen sensor. The goal of this study was to verify the operation characteristics of Delphi's fast “light-off” planar oxygen sensor's (INTELLEK OSP) operating characteristics and the closed-loop performance for achieving improved hydrocarbon control for stringent emission standards. Tests were conducted in open-loop and closed-loop mode under steady and transient conditions using a 1996 model year 2.4-liter DOHC in-line 4-cylinder engine with a close-coupled catalytic converter. Overall performance of the OSP showed relatively quick reaction time to reach the operating temperature.
Technical Paper

A New Approach to OBDII Monitoring of Catalyst Performance Using Dual Oxygen Sensors

2000-03-06
2000-01-0863
On-Board Diagnostics for emissions-related components require the monitoring of the catalytic converter performance. Currently, the dual Exhaust Gas Oxygen (EGO) sensor method is the only proven method for monitoring the catalyst performance for hydrocarbons (HC). The premise for using the dual oxygen sensor method is that a catalyst with good oxygen storage capacity (OSC) will perform better than a catalyst with lower OSC. A statistical relationship has been developed to correlate HC performance with changes in OSC. The current algorithms are susceptible to false illumination of the Malfunction Indication Light (MIL) due to: 1. The accuracy with which the diagnostic algorithm can predict a catalyst malfunction condition, and 2. The precision with which the algorithm can consistently predict a malfunction. A new algorithm has been developed that provides a significant improvement in correlation between the EGO sensor signals and hydrocarbon emissions.
Technical Paper

Testing of a Polyphenylene Sulfide Spun Cast Diaphragm in the Electrolytic Oxygen Generator (EOG)

2000-07-10
2000-01-2501
The Electrolytic Oxygen Generator (EOG) used aboard U.S. nuclear submarines to produce breathing oxygen for the crew uses an asbestos diaphragm to separate the electrochemically generated hydrogen and oxygen gas. Due to environmental, safety and economic concerns, a program to develop a substitute diaphragm material was implemented under a Naval Research Laboratory contract. Polyphenylene sulfide (PPS) was shown to be a suitable replacement material for asbestos. Initial tests using PPS cloth revealed an inadequate separation of the hydrogen and oxygen gas. A new, advanced PPS spun cast sleeve was developed, analyzed (including electron microscopy and XREF), surface-modified and then a full-scale prototype was tested. With successful full-scale testing, a complete set of sixteen EOG cells was assembled and installed in an EOG. These cells have recently completed a two thousand-hour endurance test with performance results similar to those of standard asbestos diaphragm cells.
Technical Paper

Membrane Based CO2 Removal from Breathing Atmospheres

2000-07-10
2000-01-2392
Closed-loop inhabited spacecraft, including a space suit, require removal of carbon dioxide from the breathing atmosphere. A membrane device that separates CO2 from breathing air can effectively control CO2 levels in the breathing loop by venting the carbon dioxide directly to the vacuum of space. Such a membrane device requires no regeneration and, therefore, imposes no limitations on mission length. Systematic studies have expanded our knowledge of the parameters most critical to the successful development of a membrane carbon dioxide removal system. The membrane type disclosed in this paper is an immobilized liquid membrane (ILM) in which the liquid is engineered to facilitate the transport of carbon dioxide while inhibiting the progress of oxygen. Selectivity superior to that achieved in previously published studies has been demonstrated and has approached values desired for an Extravehicular Mobility Unit (EMU) system.
Technical Paper

Atmosphere Composition Control of Spaceflight Plant Growth Growth Chambers

2000-07-10
2000-01-2232
Spaceflight plant growth chambers require an atmosphere control system to maintain adequate levels of carbon dioxide and oxygen, as well as to limit trace gas components, for optimum or reproducible scientific performance. Recent atmosphere control anomalies of a spaceflight plant chamber, resulting in unstable CO2 control, have been analyzed. An activated carbon filter, designed to absorb trace gas contaminants, has proven detrimental to the atmosphere control system due to its large buffer capacity for CO2. The latest plant chamber redesign addresses the control anomalies and introduces a new approach to atmosphere control (low leakage rate chamber, regenerative control of CO2, O2, and ethylene).
Technical Paper

Oxygen Extraction from llmenite by Hydrogen Reduction in a Sound Assisted Fluidized Bed

2000-07-10
2000-01-2241
Batches of very fine grains of ilmenite mineral (FeTiO3), close to the dimensions of ilmenite in lunar soils have been hydrogen reduced at temperatures over to 1000 K, utilizing a sound assisted fluidized bed. The feasibility of the process has been demonstrated together with the determination of process parameters. The rate of the process at fixed temperature has been experimentally determined and the water produced collected in each experience, about 10 cc for 100 g of ilmenite sample . Non destructive analyses of the products were carried out showing the formation of a layer of low porosity on the samples surface and a characteristic vein-like structure of TiO2. A possible utilization of the technique to reduce entrainment problems is envisaged from the present work.
Technical Paper

Pyrolysis Processing for Solid Waste Resource Recovery in Space

2000-07-10
2000-01-2286
The NASA objective of expanding the human experience into the far reaches of space will require the development of regenerable life support systems. A key element of these systems is a means for solid waste resource recovery. The objective of this work was to demonstrate the feasibility of pyrolysis processing as a method for the conversion of solid waste materials in a Controlled Ecological Life Support System (CELSS). A pyrolysis process will be useful to NASA in at least four respects: 1) it can be used as a pretreatment for a combustion process; 2) it can be used as a more efficient means of utilizing oxygen and recycling carbon and nitrogen; 3) it can be used to supply fuel gases to fuel cells for power generation; 4) it can be used as the basis for the production of chemicals and materials in space. A composite mixture was made consisting of 10% polyethylene, 15% urea, 25% cellulose, 25% wheat straw, 20% Gerepon TC-42 (space soap) and 5% methionine.
Technical Paper

Self-Sterilizing Properties of Martian Soil: Possible Nature & Implications

2000-07-10
2000-01-2343
As a result of the Viking missions in 1970s, the presence of a strong oxidant in Martian soil was suggested. Here we present a testable, by near-term missions, hypothesis that iron(VI) contributes to that oxidizing pool. Ferrate(VI) salts were studied for their spectral and oxidative properties and biological activities. Ferrate(VI) has distinctive spectroscopic features making it available for detection by remote sensing reflectance spectra and contact measurements via Mössbauer spectroscopy. The relevant miniaturized instrumentation has been developed or is underway, while XANES spectroscopy is shown to be a method of choice for the returned samples. Ferrate(VI) is capable of splitting water to yield oxygen, and oxidizing organic carbon to CO2. Organic oxidation was strongly abated after pre-heating ferrate, similar to the observations with Mars soil samples.
Technical Paper

International Space Station United States Oxygen Generator Development Testing

2000-07-10
2000-01-2351
A life test of a liquid anode feed oxygen generator assembly (OGA) using SPE® (United Technologies Corporation, Hamilton Sundstrand Division) membrane technology was terminated in June of 1999. In the total 15,658 hours of operation at MSFC since delivery in 1995, the OGA has produced 2,103 kilograms (kg) (4,632 pounds mass (lbm)) of oxygen, and 263 kg (579 lbm) of hydrogen. Evaluation of cell stack characteristics and oxygen and hydrogen hydrophilic/hydrophobic membrane separators will be discussed.
Technical Paper

The Design and Development of Pumps for the ISS Oxygen Generation and Water Processor Assemblies

2000-07-10
2000-01-2350
This paper discusses the design, development, materials selection and testing of two gear pumps that have been developed for use in the ISS (International Space Station) Oxygen Generation and Water Processor Assemblies. The gear pumps are used to pump both clean and contaminated water for these systems. Previous attempts to develop gear pumps that meet operating life requirements have met with limited success. Both of the pumps discussed in this paper employ special design practices and materials to meet challenging operating life requirements
Technical Paper

Bioprocessing to Recover Crop Nutrients from Advanced Life Support (ALS) Solid Wastes: Improving Rapid Biological Processing of ALS Inedible Crop Residues

2001-07-09
2001-01-2208
The overall objective of a NASA Research Announcement funded project at Kennedy Space Center (KSC) is to determine the optimal Advanced Life Support (ALS) solid waste bioprocessing system with the limited goal of nutrient recycling as part of a potential hybrid biological-physical chemical (PC) system. Bioprocess research towards this objective has focused on comparing two bioreactor technologies: (1) continuous stirred tank reactor (CSTR)-suspension culture and (2) continuous flow fixed-film bioreactor (FFB)-which utilizes biofilms to remove organic constituents from crop residue leachate solutions. For optimizing the CSTR we studied the effects of solids loading rate (160, 240, and 320 grams dry weight [gdw] day−1) and stirrer speed (45, 90, 180, and 360 rpm) on the vertical distribution (5 depths) of dissolved oxygen (> 90% oxygen in aeration gas) and total suspended solids in a CSTR operated at an hydraulic retention time (HRT) of 1.25 days.
Technical Paper

Two-Parameter Equations of State for ARPCS Applications

2001-07-09
2001-01-2251
This work summarizes the limitations of the Ideal Gas Law and the use of simple but accurate two-parameter equations of state for air, oxygen, and nitrogen in the operations of ECLS/EVA hardware. The equation-of-state parameters can be determined for pure gases and for mixtures by mixture combination rules. The parameters of two equations of state in Redlich-Kwong equation of state and Peng-Robinson equation of state have been calculated here. Technical evaluations for spacecraft applications and relevant ranges in temperatures and pressures have been performed. The equations are applicable for several ECLS subsystems: Temperature and Humidity Control, THC; Atmospheric Revitalization System, ARS; and Atmospheric Control System, ACS. The goal is to focus on equations of state for ECLS/EVA applications, especially in depress/repress/compression of air and gases.
Technical Paper

Development of de-NOx Catalyst for the Control of NOx Emissions from Lean-Burn Gasoline Engines

2001-01-10
2001-26-0019
Catalytic performance of some non-noble metal based catalytic materials has been investigated for de-NOx reactions, under normal and lean conditions. These catalysts show significant catalytic activity for NOx conversion by hydrocarbon even in presence of oxygen, while the high de-NOx activity with CO was found to be severely affected in oxygen. The surface area of catalysts has been improved following their synthesis on high surface area alumina, using special preparative techniques. These catalysts show excellent thermal stability, while their light-off characteristics have also been remarkably improved by proper application of commonly used high surface area alumina. A small amount of ruthenium metal incorporation has been found very useful with regard to their de-NOx activity and light-off characteristics.
Technical Paper

Air Revitalization, an Inevitable Prerequisite for Future Affordable Crewed Missions to Space

2001-07-09
2001-01-2291
The current ECLS baseline of the International Space Station ISS contains an open oxygen loop. Breathable oxygen, generated by electrolysis of water, is supplied to all habitable modules. The crew of max. 7 astronauts converts the oxygen into metabolic carbon dioxide, which needs to be removed from the ISS atmosphere. Adsorption of CO2 is achieved through molecular sieves, desorption of CO2 is conducted by evacuation into space. This open process needs approx. 1500 kg of water upload mass annually. More than 75 % of this upload mass can be saved, if the open oxygen loop will be closed. This paper outlines the closed loop air revitalization system of Astrium, ARES, which has been successfully tested in closed chamber tests. It demonstrates in detail the technical application of ARES on ISS and outlines the commercial benefits. The second part of the paper describes ARES for a Mars habitat with a closed oxygen and hydrogen loop.
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