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1974-02-01
Technical Paper
740489
James F. Woodall
The FAA retrofit feasibility program is a success story. The cooperation of the aircraft industry in general, and the FAA's contractors in particular have made the success of the program possible. We can now state that all JT3D- and JT8D-powered aircraft can meet reduced noise levels, such as FAR 36 levels, by means of technologically feasible and economically reasonable nacelle retrofit solutions. These solutions will not aggravate the energy crisis by virtue of a negligible increase in fuel consumption for the nominal flight conditions. A Notice of Proposed Rulemaking (NPRM) is about to be disseminated which could lead to the requirement that all JT3D/JT8D-powered aircraft be retrofitted by 1978 with quiet nacelles so that FAR 36 requirements can be satisfied.
1974-02-01
Technical Paper
740527
L. Grinberg, L. Morgan
A program has been completed to study the effects of ambient temperature on exhaust emissions. It consisted of determining the cold start emission levels of two late model passenger cars at temperatures of +70, +40, and -10°F with two test fuels of different midrange volatility characteristics. The ambient temperature was found to have a pronounced effect on exhaust emissions. A reduction of the test temperature from +70 to -10°F resulted in a manyfold increase in hydrocarbon and carbon monoxide emissions. Most of this increase in emissions, as well as an associated deterioration in fuel economy, occurred during the initial 5 min period after a cold start. The ambient temperature was found to have no major effect on the levels of pollutants emitted during the fully warmed-up operation of cars. Relative to the effects of ambient temperature and the vehicle characteristics, the midrange volatility of the fuel was concluded to have only a minor effect on exhaust emissions.
1974-02-01
Technical Paper
740529
J. T. Wentworth
The effects of combustion chamber shape and spark location on exhaust NO and HC emissions were investigated using a single-cylinder, 4-stroke, reciprocating, spark ignition engine. A total of 21 spark locations were evaluated in three combustion chamber configurations. The chamber shapes included a modified wedge, a disc, and a modified hemisphere. The engine was operated at constant speed and airflow, with optimum spark timing and peak NO air-fuel ratio. Both combustion chamber shape and spark location had substantial effects on NO and HC emissions. Deductive prediction of these effects was not possible due to incomplete knowledge of the patterns of pollutant distribution and mixture movements within the combustion chamber. It is recommended that chamber shape and spark location effects be evaluated experimentally in any new engine design.
1974-02-01
Technical Paper
740530
E. W. Landen, J. M. Perez
Chromatographic analysis of diesel exhaust indicates a number of low molecular weight hydrocarbons, below C6. Using reactivity index as a criterion, much of the diesel exhaust reactivity can be attributed to ethylene and propylene caused by the thermal decomposition of the fuel. Hydrocarbons in the C4-C7 range, including high relative reactivity olefins, are generally low in volume concentration and therefore contribute little to the overall exhaust reactivity. Hydrocarbons, in terms of parts per million carbon above C7 are low in present diesel engine designs, so individual volume concentrations are generally fractional parts per million. Reactivity per horsepower-hour from diesel engine exhaust is less than that from the one small industrial gasoline engine tested by the heavy-duty truck diesel engine cycle.
1974-02-01
Technical Paper
740538
Paul Kunselman, H. T. McAdams, Marcia E. Williams, Charles J. Domke
A mathematical model of an automobile's emission rate is described. This model can be used to calculate the amounts of hydrocarbons, carbon monoxide, and oxides of nitrogen emitted by individual or groups of automobiles being driven over any known driving sequence. The development of the model requires the amounts of three pollutants given off by individual automobiles over short duration driving sequences (modes). The validity of the model is investigated by using it to calculate the amounts of each pollutant given off by individual automobiles over the hot transient portion (first 505 s) of the Federal Test Procedure driving sequence. These predicted emissions are then compared with observed amounts emitted from each automobile. Further, the ability of the model to predict emissions is investigated in light of the reproducibility of actual automobile emissions measured in replicated tests. These analyses indicate that the model performs extremely well.
1974-02-01
Technical Paper
740537
Daniel S. Tingley, John H. Johnson
This paper presents an approach to modeling the United States truck and bus population. A detailed model is developed that utilizes domestic factory sales figures combined with a scrappage factor as a building block for the total population. Comparison with historical data for 1958-1970 shows that the model follows trends well for intermediate parameters such as total vehicle miles per year, total fuel consumption, scrappage, etc. Fuel consumption and HC, CO, NO2, CO2 and particulate matter emissions for gasoline and diesel engines are of primary interest. The model details these parameters for the time span 1958-2000 in one-year increments. For HC and CO, truck and bus emissions could equal or exceed automobile emissions in the early 1980s, depending on the degree of control. Three population control strategies are analyzed to determine their effects on reducing fuel consumption or air pollution in later years.
1974-02-01
Technical Paper
740536
John B. Heywood, Michael K. Martin
A methodology is presented with which aggregate emissions from the in-use automobile population can be calculated for any given calendar year. The data base needed for such a calculation is discussed, and areas in which further research is needed are pointed out. Results of a series of calculations are then presented showing the effect on aggregate emissions of various control strategies. The effects of an inspection/maintenance and retrofit program, different vehicle population growth rates, catalyst deterioration in use, and various schedules of new car emission standards for post-1975 vehicles are presented. It is shown that the rate at which old, higher-polluting vehicles are retired from the in-use vehicle population is the major factor in determining the rate at which aggregate emissions will decrease in the 1970s, with the precise level of post-1975 standards only becoming important in the 1980s.
1974-02-01
Technical Paper
740544
William H. Close
This paper analyzes the rationale behind the federal regulation of interstate motor carrier noise. At highway speeds, tire noise is frequently predominant. At low speeds, engine-related noise is predominant. The effects of both these noise sources are considered. The question of enforceability of the regulation is also discussed.
1974-02-01
Technical Paper
740563
M. Alperstein, G. H. Schafer, F. J. Villforth
This paper reports on the continuing development of Texaco's stratified charge engine combustion concept, the Texaco Controlled-Combustion System. TCCS conversions of the military L-141 engine have demonstrated inherently low exhaust emissions, multifuel capability, and improved fuel economy over the carburetted L-141 gasoline engine. Under contract to the U.S. Army Tank-Automotive Command, promulgated federal gaseous exhaust emissions standards were met in a naturally aspirated TCCS engine-powered M-151 vehicle equipped with EGR- and Texaco-developed exhaust catalysts. These low emissions were sustained for 50,000 miles (80,400 km) with moderate maintenance. The effects of different degrees of emission control and of multifuel operation on performance and fuel economy were characterized using a turbocharged L-141 TCCS engine-powered M-151 vehicle.
1974-02-01
Technical Paper
740564
George P. Gross
Automotive exhaust emissions of polynuclear aromatic (C16+) hydrocarbons (PNA) were reduced by 65-70% by current emissions control systems and by about 99% by two experimental advanced emission control systems. At a given level of emission control, PNA emission was primarily controlled by fuel PNA content through the transient storage of PNA in engine deposits and their later emission under more severe engine operating conditions. A relatively minor contribution to PNA emission was made by PNA synthesized from lower molecular weight fuel aromatics, particularly C10-C14 aromatics. Deposit-related PNA emissions were linearly correlated with the PNA content of the deposit formation fuel. In comparison with a fuel of field-average PNA content (0.5 ppm benzo(a)pyrene), a field-maximum fuel (3 ppm) contained 4 to 7 times as much of three major PNA species and caused 3 to 5 times higher emissions of these species.
1974-02-01
Technical Paper
740561
T. V. DePalma, Vladimir Haensel, M. J. Sterba, J. E. Thoss
New cars represent a deliberate choice to lower emissions at the expense of fuel economy. This paper considers the compatibility of emission control and gasoline conservation for the automotive vehicle. It concludes that the use of catalytic converters in combination with higher ratio compression engines will allow us to regain pre-emission control fuel economy.
1974-02-01
Technical Paper
740430
Vincent Miller
This paper discusses some of the political and social forces which led to the tremendous surge in earthmoving that we have in Brazil today. The text describes major highway and dam construction and covers new airport and railroad jobs beginning today. It is hoped that this paper will bring a better understanding of today's “Brazilian Miracle” as well as the internecessity of transport and energy in the development of a nation.
1974-02-01
Technical Paper
740484
A. W. Nelson
A new combustor configuration having substantially lower smoke emission characteristics is now in the final stages of development for the JT3D commercial aircraft turbofan engine. In addition, the low-power emissions of hydrocarbons and carbon monoxide are considerably reduced. This burner configuration utilizes many of the features developed in the JT8D turbofan engine smoke reduction program; however, it was also necessary to incorporate air-assist fuel injection nozzles to achieve smoke levels below the EPA regulation requirement of 25. Correction of a nozzle carbon formation problem and further durability testing must be accomplished before this combustor can be released for in-service commercial airline controlled-service use evaluation.
1974-02-01
Technical Paper
740483
A. B. Wassell
Progress in the application of well-known pollution-control techniques to existing engines is demonstrated in relation to the visibility of the exhaust smoke plume in the RB211 and Olympus 593 engines. The reasons for the apparently protracted nature of this progress are discussed and shown to be related to the maintenance of safety and durability standards. Methods being used to reduce the other combustion-generated pollutants are mentioned, especially in relation to the standards promulgated by the Environmental Protection Agency (EPA). A review of some problems associated with measurement and sampling of pollutants is given.
1974-02-01
Technical Paper
740969
C. W. Coon, C. D. Wood
A series of road, engine, chassis dynamometer, and accessory power consumption tests was conducted in order to characterize the fuel economy of 1973 standard and intermediate size vehicles. Devices and systems which appeared to offer fuel economy benefits were evaluated by means of an analytical procedure. The study was limited to hardware which could be in production by the 1980 model year. The evaluation procedure was based on urban and steady speed operation, and the effects of compliance with future emission standards were included. Combinations of individual improvements were selected and applied to the same vehicle. The evaluation procedure was repeated, and fuel economy improvements of 30 to 70% were predicted by comparison with 1973 model year vehicles.
1974-02-01
Technical Paper
740970
Thomas C. Austin, Karl H. Hellman
The fuel economy data obtained from the emission tests run by the U.S. Environmental Protection Agency (EPA) have been used to show passenger car fuel economy trends from model year 1957 to present. This paper adds the 1975 model year to the historical trend and concentrates on comparisons between the 1975 and 1974 models. Methodologies which allow different 1975 vs 1974 comparisons to be made have been developed. These calculation procedures allow the changes in fuel economy to be determined separately for emission control systems, new engine-vehicle combinations and model mix shifts. Comparisons have been calculated not only for the fleet as a whole but for each of the 13 manufacturers who were certified as of the time this paper was prepared. The net change in fuel economy for the fleet has been estimated at +13.8% comparing the 1975 models to the 1974 models assuming no model mix change occurs.
1974-02-01
Technical Paper
740947
R. F. Hurt, C. C. Meek, W. L. Hull
The intent of this study is to present effectual methodologies concerning single-phase and two-phase mixing problems which may conveniently be utilized by a design or developmental engineer. In particular, for single phase, turbulent, compressible coaxial fuel and air mixing problems, an index is presented which provides a sensitive indicator for determination of the degree of mixing in a given mixing chamber. Working graphs for several hydrocarbon fuel and air stream combinations are used to demonstrate the utility of the index. In addition, the index is shown to be of value for studying twophase mixing such as occurring in automotive carburetors. This paper further demonstrates the utility of the hydraulic analogy for studying complex mixing problems such as commonly occurring in automotive carburetors and manifolds, gas turbine combustors, and simple mixing chambers.
1974-02-01
Technical Paper
740949
Carlyle M. Ashley
Better fluid mixing in automobile engines can contribute to fuel economy, smoothness of engine operation, and reduction of emissions. It is possible to improve the uniformity of mixture of fuel with air in the induction system, of trapped burned gas with the charge in the cylinders, and of air with the exhaust gas in a reactor. Criteria of uniformity of mixing are discussed and a more stringent criterion suggested. The mixing length concept is developed. Fluid flow mixing models for different passage geometries are presented and evaluated for mixing length. Mixing performance of the induction system and cylinders of a typical engine are estimated. Improved mixing means are proposed and described. Maximum uniformity of distribution of the charge involves effective vaporization of fuel and mixing with the air ahead of the intake manifold. Maximum uniformity of mixture and turbulence prior to combustion involves the mixture of the trapped burned gas with the charge in the cylinders.
1974-02-01
Technical Paper
740928
C. Scott Clark, Robert D. Lingg, Edward Pesci, Edward J. Cleary
1974-02-01
Technical Paper
740931
Michael Onischak, Bernard Baker, Dimitri Gidaspow
ENVIRONMENTAL CARBON DIOXIDE CONTROL by Michael Onischak, Energy Research Corp, Bethel, Conn. A study of environmental carbon dioxide control for NASA EVA missions found solid potassium carbonate to be an effective regenerable absorbent in maintaining low carbon dioxide levels. The supported sorbent was capable of repeated regeneration below 150°C without appreciable degradation. Optimum structures in the form of thin pliable sheets of carbonate, inert support and binder were developed. Interpretation of a new solid-gas pore closing model helped predict the optimum sorbent and analysis of individual sorbent sheet performance in a thin rectangular channel sorber can predict packed bed performance.
1974-02-01
Technical Paper
740925
Edward S. K. Chian, Herbert H. P. Fang*, Martin N. Aschauer
The removal of over 40 toxic compounds, including heavy metals, synthetic pesticides and organic compounds, by cellulose acetate (CA) and crosslinked-polyethylenimine (C-PEI) membranes were examined. With few exceptions both membranes removed 97+ percent of the heavy metals and pesticides tested; the C-PEI membrane was found to be somewhat more effective than the CA membrane. In addition, the C-PEI membrane removed 70+ percent of 13 of the 19 organic compounds tested; only two compounds were removed less than 50 percent. In contrast, however, the CA membrane removed less than 50 percent of 16 of the 19 organic compounds tested, and three compounds were found to exhibit negative removal. The ability of C-PEI membrane to remove organic compounds and its resistance to high temperature and pH have made reverse osmosis an effective separation process for the removal of toxic compounds from water.
1974-02-01
Technical Paper
740927
Jack D. Zeff, Richard Barton, LeRoy H. Reuter
This paper summarizes a study of combining ultra-violet radiation and ozone to purify water contaminated with microorganisms and organic compounds. The objectives of the study were (1) to determine the feasibility of the combination of ultraviolet light and ozone to sterilize and to remove organics from water, (2) define the concentrations of ultraviolet light and ozone required to remove predetermined levels of microbial contamination and organic substances from water, and (3) to describe operating parameters for water sterilization and purification that can be used as a basis for designing operating systems that can be used by the Army and in manned space flight. The study to date has found that the combination of UV and ozone is more effective in destroying test organisms than UV alone. About 2.25 ppm ozone plus UV will destroy about 99.7 percent of the organisms present and 3 ppm of ozone plus UV will result in complete destruction of the organisms.
1974-02-01
Technical Paper
740935
Ray M. Shortridge, James O'Day
The purpose of this study was to obtain information useful for improving crash protection for small children. Previous research efforts have produced findings relating to accident characteristics in general, and those findings have been used to improve passenger protection. However, little work has focused on the particular characteristics of nonfatal and fatal accidents involving small-child passengers. Thus, this study compared accidents involving small children (five years old and younger) with accidents not involving small children, to establish the similarities and differences between those types of accidents. The principal findings of the study are briefly summarized in the following description of a composite accident in which a small child is an occupant of the car: The child is very likely a passenger in a car driven by a female between 20 and 35 years of age, who is not wearing a seat belt, and who has not been drinking.
1974-02-01
Technical Paper
740924
Robert B. Grieves, Dibakar Bhattacharyya, J. W. Paul
1974-02-01
Technical Paper
741005
J. T. White, C. J. Domke, M. E. Williams
This report describes the results of a surveillance study initiated by the U.S. Environmental Protection Agency to measure gaseous exhaust emissions from 1020 light-duty motor vehicles. This project was the second effort in a continuing program using the CVS Federal Test Procedure. Selected privately-owned vehicles, drawn randomly from six metropolitan areas, were tested in as-received condition. The emissions data obtained from these 1966-1972 model-year vehicles are reported in grams per mile of unburned hydrocarbons, carbon monoxide, carbon dioxide and oxides of nitrogen while fuel economy is reported in mpg as determined over the Federal Driving Schedule.
1974-02-01
Technical Paper
741003
James A. Tysver
General Motors has built an environmental chamber at its Milford Proving Ground to run emission tests at controlled atmospheric conditions. This chamber was designed using constant speed fans and dampers to simulate altitudes between sea level and Denver, which is approximately 5000 ft above sea level. The chamber can also control temperatures within a range of 45-100°F at humidities of 9-100 gr H2O/lb dry air. With this chamber, environmental conditions can be changed to desired levels very quickly to measure the vehicle sensitivity to the change. It is also possible to hold the environment constant and run controlled comparison studies on emission-related components to determine the effect of different distributors, carburetors, etc., relative to emission values. Past test experience has proved that vehicle emissions change with changing environment. However, the degree of change is different from one vehicle to another.
1974-02-01
Technical Paper
741006
Karl J. Springer, John T. White, Charles J. Domke
A fleet of 64 heavy-duty 1970-71 model trucks and buses powered by a variety of diesel engines were tested periodically to determine exhaust smoke behavior. Smoke tests were made when the vehicle was new or nearly new and at four month intervals thereafter, or until 160,934 km (100,000 miles) odometer reading was reached. Gaseous emissions of hydrocarbon (HC), carbon monoxide (CO), and nitric oxide (NO) were measured at one point early in the project. Both smoke and gaseous emission tests were performed with chassis versions of the engine dynamometer Federal Test Procedures (FTP). Results in terms of “a” (acceleration), “b” (lugging), and “c” (peak) smoke factors versus mileage are reported for the 13 engine-vehicle-application groupings.
1974-02-01
Technical Paper
741007
R. T. Gryce
The Ford Auto/Emission Driver System automates the driving of a test vehicle on a chassis dynamometer while it is undergoing exhaust emissions testing. The system “drives” the vehicle through the 1372 s EPA Urban Dynamometer Driving Schedule associated with the CVS-C and CVS-CH Test Procedures by applying the accelerator and brake pedals directly and also shifts the transmission if the vehicle is equipped with a standard transmission. The Ford Auto/Emission Driver System consists of a hybrid analog and digital electronic control console including a magnetic tape recorder and a servo hydraulic mechanical console linked to universal interface fixtures in the vehicle via flexible mechanical push-pull cables. The high response hydraulic rams are mounted remote from the vehicle to permit design of actuating fixtures which are compact, light weight and therefore easy to install.
1974-02-01
Technical Paper
740815
Clark J. Beck
Recent experience with vibration qualification of avionics for the B-1 airplane has revealed deficiencies in commonly used vibration design and test procedures. Specific examples of deficiencies are discussed. Recommendations for improving vibration design and test procedures are presented in the areas of environment prediction, qualification testing, and use of vibration isolators. Suggestions are made relative to vibration design and testing in light of the “try-before-buy” concept.
1974-02-01
Technical Paper
741223
Hermann Eisele
Recent development effort concentrated on further improvement of emission control and fuel economy. The Bosch electronic fuel injection was advanced from using absolute intake manifold pressure as main input variable to an air metering system. This approach simplifies emission control combined with less cost gained by other improvements. Better fuel economy in combination with low emissions is achieved by closed-loop control employing the λ-sensor. The structure of this control loop allows the application of a self-adaptive control system responding to changing operating conditions of the engine. A further possibility is the closed-loop control at air-fuel ratios slightly richer or leaner than stoichiometric. This application widens the use of the λ-sensor to different emission control packages dependent on applicable standards.
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