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1971-02-01
Technical Paper
710006
Gerhard Reethof
The increasing levels of affluence in the highly industrialized western societies have resulted in a drastic and increasing deterioration of the quality of man's environment. The economic facts in these societies are such that it actually “pays to pollute.” Air and water pollution, solid waste disposal, and noise pollution have become areas of major concern for the institutions of higher learning. Through instruction and research, knowledge toward the alleviation and control of environmental pollution must be disseminated and advanced. One of the major contributors to the present state of environmental deterioration is the almost absolute lack of well-defined control criteria. Much needs to be done in this area and the academic community has the know-how and economic remoteness to tackle this problem. One of the most fascinating facets of the environmental pollution problem is its interdisciplinary nature.
1971-02-01
Technical Paper
710005
J. G. G. Hempson, M. H. Howarth
Introducing the direct study of environmental problems into university courses seems too difficult. The only practical way of alerting future engineers to their responsibility in considering the effect of their activities on the environment is indirectly. The development of courses in instrumentation and the use of experimental equipment are effective and do not require substantial modification of an engineering cirriculum. The intention of this paper is to describe certain experimental work to illustrate their use in the field of environmental problems.
1971-02-01
Technical Paper
710012
R. D. Fleming, D. B. Eccleston
A single-cylinder research engine was operated on pure hydrocarbons (HC) and simple mixtures of pure hydrocarbons to study the effect of fuel composition, equivalence ratio, and mixture temperature on exhaust emissions. Used as fuel components were hydrocarbons-n-pentane, 2-methyl-2-butene, isooctane, and m-xylene. Total hydrocarbon emission in terms of moles of exhaust HC/mole of fuel input was lowered by increasing the amount of xylene in the fuel when operating on the fuel-rich side of stoichiometric; total hydrocarbon emission was higher for higher aromatic fuels when air-fuel ratios approached the lean misfire limit; the effect of mixture temperature on hydrocarbon emission was insignificant. 1-Methyl-3-ethylbenzene was observed as a synthesis product of combustion in the exhaust from fuels containing m-xylene. With increasing m-xylene concentration in the fuel, the yield of 1-methyl-3-ethylbenzene increases, reaches a maximum, and then decreases.
1971-02-01
Technical Paper
710013
G. S. Musser, J. A. Wilson, R.G. Hyland, H.A. Ashby
Exhaust gas recirculation (EGR) was found to be an effective means of reducing automotive NOx levels with no major unsolvable problems over 52,000 miles under city/suburban driving conditions. Compatible with air injection and engine modification systems for HC and CO control, EGR effectively reduced the NOx levels with no decrease in reduction over the 52,000 miles. Engine wear and engine cleanliness with EGR was normal for the mileage and driving regime. However, the throttle area and exhaust valves were found to be sensitive to leaded fuels.
1971-02-01
Technical Paper
710014
L. S. Bernstein, K. K. Kearby, A. K. S. Raman, J. Vardi, E. E. Wigg
Nickel-copper alloys, marketed under the name Monel, have been found to be extremely active NOx reduction catalysts. At temperatures above 1300 F, and under net reducing conditions, Monel will catalyze the removal of 90% or more of the NO in automotive exhaust at space velocities of up to 100,000 v/v/hr. On unleaded fuel, Monel catalysts have shown good activity maintenance in mileage accumulation runs as long as 31,000 miles. Catalyst life is limited by physical deterioration of the catalyst which causes increases in exhaust back pressure. On unleaded fuel, Monel in its present form will last approximately 10,000 miles at 1700 F (∼60 mph) before back pressure begins to rise rapidly. The presence of lead in the fuel substantially increases the rate of Monel deterioration. When Monel is used as part of a dual-bed catalyst system two problems, which appear to be generic to dual-bed catalyst systems, arise.
1971-02-01
Technical Paper
710007
Kenneth W. Ragland
While it is recognized that man's technological demands are degrading the earth's biosphere, there is little agreement on what to do about it. What part has engineering played in all this? How can engineers contribute to the solution of ecological problems? Is the answer an “ecological ethic” and if so, how can it be developed? A discussion of these dilemmas and the role the university can play in developing educational programs involving both the natural and life sciences to establish an ecological ethic and help resolve some of the major environmental problems, is presented. The paper also explores how these programs can be made part of an engineer's education.
1971-02-01
Technical Paper
710008
J. D. Benson, R. F. Stebar
The effects of charge dilution on the exhaust emission of nitric oxide (NO) from a single-cylinder engine were evaluated over a range of engine design and operating parameters. Nitric oxide emission decreased as much as 70% as charge dilution fraction (volume fraction of product gases in the combustion chamber prior to ignition) was increased from 0.065 to 0.164 due to increased valve overlap, external exhaust recirculation, and reduced compression ratio. With these three variables, NO emission was strongly dependent on charge dilution fraction, but was independent of the specific method used to change charge dilution. Other variables such as valve overlap position, spark timing, and exhaust pressure also affected charge dilution and NO emission, but the relationship between charge dilution fraction and NO emission for these variables was not consistent.
1971-02-01
Technical Paper
710009
Ather A. Quader
This study was undertaken to develop a better understanding of how intake charge dilution by various gases affected nitric oxide (NO) emission from a single-cylinder spark ignition engine. Carbon dioxide, nitrogen, helium, argon, steam, and exhaust gas were individually added to the intake charge of a propane-fueled, single-cylinder engine operated at constant speed and load. Nitric oxide emission was reduced in all cases. The gases with higher specific heats gave larger NO reductions. The product of diluent flow rate and specific heat correlated with NO reduction. The effects of diluents on calculated combustion temperature, mbt spark timing, and fuel consumption are also presented and discussed.
1971-02-01
Technical Paper
710010
S. Ohigashi, H. Kuroda, Y. Nakajima, Y. Hayashi, K. Sugihara
Earlier work has demonstrated that exhaust gas recirculation (EGR) decreases peak combustion temperature and thus reduces the concentration of nitrogen oxides (NOx) in spark ignition engine exhaust. The present authors hypothesized that NOx formation is primarily affected by the heat capacity of the combustion gases and recycled exhaust. The hypothesis was tested in an experimental program involving the admission of inert gases such as He, Ar, H2, and CO2, and water in place of EGR. In addition to confirming the validity of the original hypothesis, the test data also indicated that engine output and efficiency were significantly affected by the heat capacity of the combustion gases. The authors conclude that EGR functions by increasing the heat capacity of the working fluid, and demonstrates that the correlative changes in NOx and engine performance can be predicted from heat capacity considerations.
1971-02-01
Technical Paper
710508
James F. Arndt
Over the past 50 years, an estimated 30,000 tractor operators have been accidentally crushed under their overturned vehicles. During that time, stability, preventive devices, and education have been tried to reduce the number of such accidents. Within the past 15 years, worldwide activity has been concentrated on developing adequate roll-over protective structures (ROPS) for operator protection. In order to measure the adequacy of the structures, various worldwide performance standards have been created. The latest include those of the SAE, which recognizes the need for a ROPS to absorb energy in order to minimize injury to the operator.
1971-02-01
Technical Paper
710428
John Stockham, Howard Betz
The objective of this study was to relate the visibility of inflight jet exhaust to the AIA smoke number. A method based on photographic photometry was developed for measuring the optical density of smoke plumes. This method was related to visibility and to the smoke number through transmissometer measurements and visibility theory. A portable transmissometer, capable of operating over a wide range of optical path lengths and under varying ambient light conditions, was fabricated for use on this study. The mathematical expression relating the transmission measurements to the smoke number was derived. Liminal visibility requirements of smoke trails, developed from light scattering theory, correlated with actual visual observations and the transmissometer and photometry measurements. Test results, with the engines investigated, indicate that AIA smoke numbers below 23 were associated with invisible exhaust plumes.
1971-02-01
Technical Paper
710429
Eloy R. Lozano, Ralph E. George
A summary is presented of the results of a comprehensive air pollution study conducted by the Los Angeles County Air Pollution Control District (LACAPCD) under contract with the Air Pollution Control Office of the Environmental Protection Agency. Included in the data obtained are the results of exhaust testing, emission estimates of aircraft and airport ground operations, measurements of the atmosphere in the immediate environs of the airport, and passenger cabin measurements. The data indicate that the CO emissions from airport ground operations exceed levels generally attributed to commercial jet aircraft. Passenger cabin CO measurements during startup and taxiing procedures indicate average levels of 2-7 ppm. Air quality levels in the residential areas around the airport indicate average 6 hr CO concentrations of 3-11 ppm.
1971-02-01
Technical Paper
710413
Clyde W. Pace
This paper provides information on the Airport Certification Program, including the certification/safety inspection procedures and a list of minimum safety standards that will be contained in the Federal Aviation Regulations (FAR). Any additions or modifications to the minimum safety standards will be updated by the author at the May 10, 1972 SAE Meeting.
1971-02-01
Technical Paper
710404
Arnold E. Anderjaska
Fatigue substantiation of wing structure on small airplanes is now required by the Federal Aviation Regulations for civil type certification of new designs. Methods for substantiation of this structure under the “safe-life” concept, including suggested loading spectra and procedures for strength determination are outlined. The background leading to these methods and a basis for establishing scatter factors are presented. Procedures for substantiation under the “fail-safe” concept are also given.
1971-02-01
Technical Paper
710403
R. D. Christian
A Project Group of representatives of General Aviation Manufacturers Association (GAMA) companies was established and given the assignment to study several methods of fatigue evaluation and recommend procedures for compliance with new FAA regulations concerning fatigue of aircraft wings. The group held several meetings in which sources of data and the major problems associated with fatigue evaluation were discussed. The author served as chairman of the Project Group and reports in this paper on the studies and recommendations made by the group.
1971-02-01
Technical Paper
710370
W. C. Zegel, A. F. Souza, L. R. Reckner
The purpose of this study was to evaluate exhaust emissions of representative aircraft as they were flown in a normal manner. At the same time, the extent of afterburning was measured by sampling the exhaust plume downstream of the exhaust stack and comparing the plume composition, corrected for dilution, to the composition of the stack gases. Exhaust emissions from nine light aircraft were determined, using a nine-mode takeoff-cruise-landing (TCL) cycle developed for this study. Exhaust component concentrations and fuel consumption rates were measured for each mode during ten test flights per aircraft. Pollutant concentrations were converted to emission rates per pound of fuel, per minute, per mode, per TCL cycle, and per landing-takeoff (LTO) cycle.
1971-02-01
Technical Paper
710364
S. S. Sorem
Possibilities for the reduction of automobile emissions by changes in gasoline composition have been reviewed. Small benefits are achievable by limiting front end volatility and light olefin content. California has already passed legislation which places limits on these fuel properties. Fuel hydrocarbon type, octane number, and lead antiknock content are interrelated. Maintenance of octane number while removing lead can be achieved by increasing the fuels aromatic content with a resulting increase in some aspects of the exhaust's reactivity. Alternatively, lead may be removed without changing hydrocarbon composition if the engines octane number requirement is reduced. These changes may result in lower exhaust hydrocarbon content. They will result in lower engine efficiency and hence higher exhaust flow rates. The net effect on pollutant emissions is in doubt. Gasoline additives, other than lead, make little direct contribution to the pollutant content of exhaust.
1971-02-01
Technical Paper
710362
C. G. A. Rosen
The widely recognized necessity for substantially reducing air pollution caused by the automotive powerplant before the end of the century has, led to much experimentation. Both government and industry must bear the responsibility for improving the engine itself and the fuel it consumes. Promising alternatives to present vehicles include a gas turbine engine with regenerator, a hybrid engine combining a low-powered, fuel-burning engine with electric batteries. New fuels-the currently available low-lead and no-lead gasolines, natural gas and liquid propane gas, dual fuel systems, and even fuel cells-are also being investigated. Cars incorporating the eventual solution, closed-loop systems, should be available by the year 2000.
1971-02-01
Technical Paper
710365
G. A. Lacy
The efforts of the automobile industry to reduce exhaust emissions have resulted in many improvements and reductions of exhaust pollutants in the past 10 years. The facts presented in this paper tend to refute the necessity for stricter legal restrictions on antipollution components in cars, and it is suggested that the additional costs that buyers will assume could well be directed elsewhere to better advantage in controlling atmospheric pollution.
1971-02-01
Technical Paper
710559
H. Chaput
This paper describes techniques and other significant factors to satisfy good maintenance, consistent with the control and abatement of diesel exhaust emissions in urban transit operations. Major stress is placed on the use of instruments, not only for inspection, diagnosing, and correcting obvious faults which cause black and blue smoke, but also for monitoring engine deterioration and indicating when motor and torque oil should be changed. Engine wear is cited as the major enemy to both engine life and control of less obvious yet more troublesome emissions-and fuel dilution and dirty engine conditions as major causes of wear. The use of new devices to reduce fumes and an approach to engine and component replacement for an optimum balance between long life and good performance are described.
1971-02-01
Technical Paper
710583
Loren G. Pless
Vehicle emission control systems can markedly affect the environment within the engine crankcase, and could thereby increase engine deposits, wear, and oil degradation. Tests run using 1965-1970 model United States passenger cars, operating with leaded commercial gasolines in several types of service, evaluated the effects on deposits and wear of three types of experimental vehicle emission control systems: 1. Crankcase storage systems for reducing vehicle evaporative emissions. 2. An exhaust gas recirculation (EGR) system for reducing oxides of nitrogen. 3. Positive crankcase ventilation (PCV) systems for controlling crankcase emissions. In engines operated with production crankcase purging rates, crankcase storage increased engine rusting in short-trip service, and increased sludging and valve train wear in low-speed, stop-and-go service.
1971-02-01
Technical Paper
710585
N. E. Gallopoulos
Future low emissions engines will burn unleaded gasoline. Compared with engines of 1970, future engines will have lower concentrations of NOx in the blowby gases, and lower blowby flow-rates; however, oil temperatures will probably be unchanged. The consequences of these conditions for engines using high quality (SE) oils at current drain intervals are: virtual elimination of rust, reduction of sludge, no effect on wear and oil thickening, and possible worsening of varnish. Therefore, extension of the drain interval with SE engine oils in the future may be possible, but final decisions will depend on the findings of research in the areas of engine wear and varnish, and oil thickening.
1971-02-01
Technical Paper
710587
J. T. Wentworth
The relationship between surface temperature and exhaust hydrocarbon concentration was explored by installing surface thermocouples at three locations in the combustion chamber of a single-cylinder engine. Coolant temperature, coolant passage surface scale, and ethylene glycol in the coolant affected exhaust hydrocarbon concentration through changes in surface temperature. As power output increased, combustion chamber surface temperature rose, and exhaust hydrocarbon concentration fell. The increase in surface temperature accounted for about 43% of the decrease in hydrocarbon concentration. The reason for the other 57% of the decrease is unknown, but it may have been caused by increasing gas temperatures in the quench zone. Increasing surface temperature by engine modification would be expected to have adverse effects on engine octane requirement, volumetric efficiency, and oil oxidation.
1971-02-01
Technical Paper
710220
N. A. Henein
The purpose of this paper is to develop some concepts for the mechanisms of emission formation during the combustion of liquid fuel sprays injected in swirling air. An emphasis is made on finely dispersed sprays used in open chamber diesel engines. The emissions studied are the unburned hydrocarbons, carbon monoxide, aldehydes, smoke particulates, and oxides of nitrogen. The spray is considered to be composed of a group of droplets of different sizes. The behavior of these droplets is determined by studying a mathematical model for droplet evaporation and ignition. The spray is then divided into regions, depending on the mechanism of combustion in each region. The emissions formed in each region are examined. The concepts developed for the formation of the different emissions in the spray are used for a qualitative analysis of some engine experimental data.
1971-02-01
Technical Paper
710190
Paul D. Agarwal
Emissions of air pollutants at the powerplants to generate the energy required to charge the batteries for electric cars are calculated and compared with those from IC engine automobiles that will meet emission standards proposed by the U.S. Department of Health, Education, and Welfare. The relative effect of these two types of vehicles on the environment will depend on the degree of emission controls imposed on electric powerplants. The data based on present information shows that electric cars would result in more pollutants than gasoline powered vehicles with emission controls, and hence, aggravate the air pollution problem on an area wide basis. How this picture may change in the next thirty to fifty years is also examined.
1971-02-01
Technical Paper
710142
A. F. Gerber, R. G. Smith
With control of oxides of nitrogen from automobile exhaust scheduled for 1971 in California, and expected to be applied nationwide in the future, the recirculation of exhaust gas appears promising as a method of lowering NOx emissions. This paper discusses work done to evaluate effects of exhaust gas recirculation on intake system cleanliness and crankcase lubricant performance. Intake system effects were evaluated with respect to the formation of deposits in the carburetor, intake manifold and ports, and intake valve tulips. Crankcase lubricant performance was evaluated with respect to both low-temperature deposition and high-temperature oxidation and copper lead bearing corrosion characteristics.
1971-02-01
Technical Paper
710136
P. J. Clarke
The volatility of motor gasoline has always been a key factor in good car performance. It continues to be important to the driveability and emissions of late model cars equipped with exhaust and evaporative control systems. Three research studies have helped to define the role of volatility in late model vehicles. The first, a consumer reaction survey, shows that driveability in cold weather is markedly improved by high mid-fill and back-end volatility. Results from the second program indicate that cars with exhaust and evaporative control systems will perform satisfactorily on fuels of current front-end volatility levels. There will not be a problem with odor in a garage even with fuels of high front-end volatility. Also, varying front-end volatility from low to high levels did not significantly increase the average start-up time for a group of eight cars under hot start conditions.
1971-02-01
Technical Paper
710158
L. J. Muzio, E. S. Starkman, L. S. Caretto
Temperature variation in the combustion chamber of spark ignition engines is a vital factor in determining exhaust pollutant concentrations. Oxides of nitrogen are particularly affected. The temperature and concentration variations were investigated both theoretically and experimentally. A nonuniform model of the combustion process was developed. Calculations based on this model show that a temperature difference of the order of 600 K can be established across the cylinder. The validity of this model was substantiated by results of infrared spectroscopic measurements in the operating engine cylinder. The kinetic mechanism for formation of nitric oxide was used, along with the nonuniform combustion model, to investigate the formation of nitric oxide in the cylinder. Results of the kinetic calculation show that the temperature gradient across the cylinder has a profound effect on the nitric oxide formation.
1971-02-01
Technical Paper
710164
James G. Hansel
Some of the major factors contributing to cycle-to-cycle combustion variations in an automotive engine have been determined over a wide range of air-fuel ratios. The combustion variations lead to a general degradation of the combustion processes at very lean air-fuel ratios, which, in turn, places limits on operating an engine very lean to achieve low exhaust emissions.
1971-02-01
Technical Paper
710159
Takeshi Tanuma, Kenichi Sasaki, Touru Kaneko, Hajime Kawasaki
Misfire and cycle-to-cycle combustion variation are both serious problems in securing good engine performance and low exhaust emissions in the case of using extremely lean mixtures. Making some modifications in the ignition system and in the combustion chamber, and increasing the mixture turbulence, we examined their effects upon the lean limit, the engine performance, and the exhaust emissions. It was found that gap width and gap projection of a spark plug and spark energy as well as mixture turbulence had a great effect on extending the lean limit and improving engine performance with lean mixtures. A compact combustion chamber is preferable for lean mixture operation. Smooth operation of the engine can be maintained even at retarded spark timing by applying the above-mentioned items and providing hot intake air to the engine. Consequently, exhaust emissions, including hydrocarbons and oxides of nitrogen, can be substantially reduced.
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