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1968-02-01
Technical Paper
680081
John H. Lienesch, Wallace R. Wade
Continuing Stirling engine development at General Motors has uncovered advantages of the powerplant never before fully appreciated. Smoke, odor, noise, and exhaust emission measurements indicate the attractiveness of the engine for applications in a “social” environment. Design details, particularly the external combustion system, are described here only in relation to low emission level. Measurements indicate that smoke and odor are practically undetectable. Sound measurements demonstrate the relative quietness of the engine. Additional data show that exhaust emissions, while very low, exhibit a strong dependence on burner design, air-fuel mixture ratio, burner inlet temperature, and exhaust recirculation.
1968-02-01
Technical Paper
680234
Charles D. Pratt
Air pollution caused by toxic fumes from the internal combustion engine is a concern to public health. The effects of the exhaust emissions, carbon monoxide, hydrocarbons, oxides of nitrogen, and aerosols on human beings are discussed, and caution is urged for proper ventilation of enclosed garage and industrial areas.
1968-02-01
Technical Paper
680242
Fred W. Bowditch
Since the late 1940's automotive engineers and scientists have been conducting research on emission control and developing the results into practical hardware for the four sources of emission from the automobile -- the crankcase, the exhaust, the carburetor, and the fuel tank. It is estimated that 20% of all hydrocarbon losses are divided between the carburetor and the fuel tank and, at present, there is no system available for controlling these losses. The exhaust accounts for 60% of the hydrocarbons and practically all the carbon monoxide. The remaining 20% of the hydrocarbons are emissions from the crankcase. Present control systems make substantial reductions in the emissions from these two sources. Under present levels of control there is a total reduction of about 60% in both total hydrocarbon and CO emissions. Another factor important to emission control is the need for proper maintenance.
1968-02-01
Technical Paper
680241
P. S. Myers, O. A. Uyehara
This paper reviews the source of the different emissions from an automobile. The exhaust is the major source of air pollution. This is composed of completely oxidized constituents such as H2O and CO2, both of which are considered harmless. Emphasis is placed on the partially oxidized components -- nitrogen oxide, carbon monoxide, and hydrocarbons -- as being the major pollutants. NO and CO are formed primarily in the bulk gases, whereas hydrocarbons are formed in the quench area. Discussed are several possible methods that could be considered in attempting to eliminate these pollutants. The authors are confident an answer will be found to this emission problem and that internal combustion engines will be used to power private vehicles rather than electricity.
1968-02-01
Technical Paper
680192
Werner Buttgereit, Christoph H. Voges, Christoph Schilter
The 1968 models of the VW 1600 sedan for the U. S. market are equipped with an electronically controlled fuel injection system. These vehicles comply with existing exhaust emission standards. Engine fuel requirements for constant operating conditions were determined by exhaust gas analysis. The test results furnished the basis for fuel metering by means of an electronic control unit. Deceleration fuel shutoff and closely controlled mixture enrichment for cold starting, warmup and full load ensure low emissions and good driving characteristics. Push-button checks for all the major circuit functions can be carried out with a special checking instrument.
1968-02-01
Technical Paper
680179
Richard S. Morse
The image of a large corporation in today’s technical world is, in many instances, dependent upon its interest in the innovative process and adaptability to change. Air pollution poses a serious threat to this country. In an effort to implement recommendations for the control of automotive air pollution, the more important findings of a government study group (fully reported in “The Automobile and Air Pollution: A Program for Progress”) are summarized. The development of effective means to infuse new ideas into the automotive industry is discussed.
1968-02-01
Technical Paper
680191
Jay A. Bolt
The automotive gasoline engine has been under heavy attack as a source of air pollution, and is now the subject of a very large program of research and development to reduce its undesirable vehicle emissions. The quantity of emissions that can reasonably be tolerated in different areas of the U.S. is presently unknown because of lack of information concerning air movements and air quality standards for man and plants. It is important that this information be made available as quickly as possible because the cost of emission controls of all types will rise rapidly. With rapidly rising costs for air pollution control from all sources, cost-value analyses are urgently needed for economy. Major reductions of the undesirable exhaust emissions of present powerplant systems have been made during the last few years and will continue to be accomplished, under the impetus of air pollution requirements and regulations.
1968-02-01
Technical Paper
680345
S. C. Fiorello
The Navy is engaged in programs to reduce the visible smoke emitted by gas turbine engines. These programs include the use of alternate fuels, the use of smoke suppressant fuel additives, and the use of combustor design technology. The current status in each of these areas is presented, as is a review of previous investigations. Tests of alternate fuels have shown that a significant but inadequate reduction of smoke was obtained. Of the fuel additives tested, one additive has shown superior performance to the others, and is suitable for use in certain engines. In order to determine the potential smoke reduction possible through combustor design, the combustion system of several engines is being redesigned. Some of the results of the redesign programs are discussed. Also presented is a brief description of the most commonly used methods of smoke measurement.
1968-02-01
Technical Paper
680347
T. Durrant
The main forms of atmospheric pollution by gas turbine exhaust are smoke and oxides of nitrogen at top speed and unburned fuel and carbon monoxide at engine idle conditions. Smoke trails constitute a visual nuisance and the other contaminants are either toxic or irritant or both. Combustor design with improvements in fuel air mixing and the use of air assisted sprayers will reduce smoke to barely visible levels on future engines. In addition, the latest annular chambers will give reduced concentrations of unburned fuel and carbon monoxide. Oxides of nitrogen will be difficult to reduce but current concentrations are less than measured on the automobile.
1968-02-01
Technical Paper
680348
J. J. Faitani
Results of experimental testing show that smoke can be significantly reduced by increasing the amount of air admitted to the primary zone. However, the location of the air entry ports, manner of air injection, and fuel spray quality are critical factors. Significant changes in combustor stability, ignition, carbon deposition, and durability characteristics are affected by the alteration of the primary zone fuel and airflow pattern. Extensive work has also been required to develop smoke measuring systems. A modified Von Brand Filtering Recorder has been selected as the standard measuring system.
1968-02-01
Technical Paper
680339
Seymour Hochheiser, Elroy R. Lozano
Pollution emissions due to jet aircraft operations at the major commercial airports in the New York Metropolitan Area were estimated. The impact on air pollution of the region was assessed. Pollutants considered in this report were: carbon monoxide, nitrogen oxides, hydrocarbons, aldehydes, and particulates.
1968-02-01
Technical Paper
680527
Shizuo Yagi, Kazuo Nakagawa, Akira Ishizuya, Yasuhito Sato
In the small displacement, high-speed, high-performance spark ignition engines being developed by Honda, the difficulties in reducing exhaust emissions without seriously impairing inherent engine characteristics are different from those encountered with the large displacement engines generally used in American cars. This paper reports on some of research in the following areas: 1. Development of a control device to minimize exhaust emissions during the frequent accelerations and decelerations in normal driving conditions. 2. Application of the air injection reactor system in small displacement engines. 3. The effect of “squish action” in a hemispherical combustion chamber on exhaust emissions. Through research and development, many of the difficulties were overcome and satisfactory results have been obtained in exhaust emission control under certain limited operating conditions.
1968-02-01
Technical Paper
680529
M. C. Baxter, G. W. Leek, P. E. Mizelle
A 1966 compact van, converted to operate on LP-gas and evaluated under the federal exhaust emissions procedure, approached several definitions of a “pollution-free vehicle.” Specific pollutant results were as follows: 1. The hydrocarbon and carbon monoxide levels of 126 ppm and 0.3%, respectively, were below the 1968 and 1970 emission limits. 2. Certain LP-gas fuel system designs promise to eliminate all evaporative losses. 3. The exhaust hydrocarbons were 70% less reactive than those in gasoline exhaust. 4. Aldehydes, a highly reactive class of exhaust compounds, were low. 5. Oxides of nitrogen were significantly higher with LP-gas because of operation at maximum economy mixtures and maximum power spark advance. 6. The use of a catalytic muffler and rich LP-gas mixtures produced very low oxides of nitrogen levels with other pollutants below the 1968 limits.
1968-02-01
Technical Paper
680528
W. F. Marshall, R. W. Hum
Smoke, odor, and other emissions of concern in environmental pollution from four diesel engines were studied experimentally; engine design, operational mode, and fuel characteristics were considered as variable factors influencing the emissions. The engine included a turbocharged 4-cycle unit, normally aspirated 4-cycle units, and an air-scavenged 2-cycle engine. All were direct injection, truck-type power units. Fuel characteristics differed widely among eight fuels used in the study, with principal differences occurring in sulfur and aromatic content. Results of the experimental study showed that emissions levels in all categories are markedly influenced by engine operation. Within the group of engines tested, generally high emissions of unburned hydrocarbon are associated with the 2-cycle design, high smoke levels with the 4-cycle normally aspirated engines, and high emissions of NOX and oxygenates with the turbocharged 4-cycle engine.
1968-02-01
Technical Paper
680443
Ralph C. Stahman, George D. Kittredge, Karl J. Springer
A program of research on diesel smoke and odor was sponsored by the U.S. Public Health Service by contract with Southwest Research Institute. A test facility was developed in which full-scale trucks and buses were operated on a chassis dynamometer through operating modes that yielded maximum exhaust smoke and odor. A system of exhaust dilution was employed to provide realistic odor concentrations to a panel of judges who rated the intensity and quality of the exhaust in terms of a set of chemical standards. Smoke levels were measured with a PHS-designed full-flow optical smokemeter. After an initial baseline evaluation of groups of buses and trucks with standard engines, various control techniques were evaluated to determine their effectiveness in reducing smoke and/or odor. Chemical analyses of the exhaust were made for the purpose of correlating the smoke and odor reductions with changes in exhaust composition.
1968-02-01
Technical Paper
680444
L. R. Reckner, R. E. Squires
A technique for measuring the intensity of diesel exhaust odor using a human panel has been developed and evaluated. While the ratings obtained are primarily useful for comparative tests, the degrees of difference which can be shown to be significant is sufficiently small to make the procedure adequate for practical use. The panelists were selected on the basis of superior olfactory ability and trained to rate the odor of diluted diesel exhaust against a series of 12 odor intensity standards contained in plastic bottles. The exhaust was diluted at the engine exhaust pipe and flowed dynamically through the presentation system in order to maintain its quality and intensity. The panelists were exposed to the diluted exhaust in a 1/2 cu ft sniff box for approximately 5 sec. The test programs of observations used were statistically designed. The resulting data were analyzed for significance of differences and confidence limits were determined.
1968-02-01
Technical Paper
680445
Gerald J. Barnes
Exhaust gas odor threshold dilution ratios were measured during idle operation of a single-cylinder 4-stroke cycle diesel engine using n-heptane as a fuel. Odor threshold dilution ratios were determined by a single panelist using a sample presentation termed the Sniff-Mask technique. The effect of various changes in the intake atmosphere composition on odor thresholds was determined. These composition changes fall into two general classes: 1. Substitution of the inert gases argon, helium, and carbon dioxide for the nitrogen contained in the normal intake air. 2. Addition of the inert gases argon, nitrogen, and carbon dioxide to the normal intake air. The substitutions of argon and helium produced a 15 fold reduction in the exhaust odor thresholds, while the substitution of carbon dioxide increased the odor threshold by a factor of 4. Directionally similar results were found for the addition experiments.
1968-02-01
Technical Paper
680463
C. G. Haupt
Exhaust emissions from a single shaft, nonregenerative, 90 hp gas turbine were measured at no load, two-thirds load, and full load operation on two fuels, regular kerosine and l% wt sulfur gas oil, and analyzed for sulfur dioxide, sulfur trioxide, nitrogen oxides (as NO2). unbumt hydrocarbons (hexane), aldehydes (formaldehyde), and exhaust solids. Additionally, the carbon monoxide content of the exhaust gases was continually monitored as an indication of possible changes in the engine combustion performance. This paper reports concentration levels of the various constitutents at varying engine loads for each of the two fuels.
1968-02-01
Technical Paper
680462
R. F. Sawyer, E. S. Starkman
With the exception of nitric oxide, exhaust emissions from a wide variety of gas turbine engines for both land and air propulsion are at levels below present and projected air pollution standards. It is proposed that emission levels be reported on a basis related to fuel consumption. Experimental data on emission levels of carbon monoxide, hydrocarbons, and oxides of nitrogen are reviewed and compared. Equilibrium and kinetic interpretations of the observed emissions are presented.
1968-02-01
Technical Paper
680398
Lucien Duckstein, Michael Tom, Louin L Beard
This paper deals with two variables affecting the pollutant emission of automotive vehicles: the driver and the traffic control. These factors are shown to have a substantial influence on the pollutant emission of a given vehicle, whether or not that vehicle has an exhaust device. Based on actual data, a function which gives the emission of an average vehicle versus speed, acceleration, and time is defined. To study the influence of driver behavior, a simplified version of the problem which consists in controlling a vehicle through a sequence of lights is examined; it is found that pollutant emission may vary up to one order of magnitude, depending on the control policy, for given physical conditions. A driving policy which minimizes pollution can be found using dynamic programming. The second factor, traffic control, is represented by signal timing along an axis. It is shown that a stop-and-go flow of cars produces twice as much pollutant as an equivalent volume of smooth flow.
1968-02-01
Technical Paper
680418
R. W. Hurn, W. F. Marshall
Methods used in diesel emissions measurement at the Bartlesville Petroleum Research Center are described; limitations, adequacy, and needs for further development of each are discussed. Smoke measurements are reported from work with the Hartridge meter, as well as newly developed instruments that are used to view smoke plumes directly, and which seem to offer advantage over smokemeters previously used. Experience in odor assessment by a human panel using reference odor materials is reported as encouraging. Odor intensity is judged with much greater reliability than odor quality; capability to assess the latter remains wholly inadequate. Results in application of the methods for measuring diesel emissions are intended to illustrate the use of experimental techniques to reveal engine and fuel factors as they influence the character, amount, and air-polluting effect of diesel emissions.
1968-02-01
Technical Paper
680419
John H. Johnson, E. J. Sienicki, O. F. Zeck
The method of flame ionization was used for measuring total hydrocarbons in both single-cylinder and multicylinder 4-cycle, direct injection diesel engine exhaust. Use of the emission parameters of hydrocarbon concentration, per cent unburned fuel, specific hydrocarbon rate, mass of hydrocarbons per million cycles, mass of hydrocarbons per mile, and mass of hydrocarbons per ton-mile are discussed. The basic approach used in the flame ionization detector is shown. The hydrocarbon sample was transferred from the exhaust system through a heated sample line and oven operating at 375 F. The sample line was aspirated to reduce the sample residence time to 2 sec. The effect various sampling locations have on hydrocarbon measurements from a single-cylinder engine is shown and discussed. The effects of load, speed, and injection timing on hydrocarbon emission data are shown for a single-cylinder engine.
1968-02-01
Technical Paper
680420
V. S. Yumlu, A. W. Carey
The exhaust emission characteristics of 4-stroke, direct-injection diesel engines, naturally aspirated and turbocharged, have been investigated. Data on the emissions of carbon monoxide, oxides of nitrogen, and unburned hydrocarbons are presented. It is shown that concentrations of these emissions increase with increasing fuel-air ratio. Turbocharged engines, by virtue of running at generally lower fuel-air ratio, tend to produce lower concentrations at equivalent loads and speeds.
1968-02-01
Technical Paper
680422
David F. Merrion
The exhaust emissions of the 6V-71E and 6V-71N engines, used in transit coaches, are compared to illustrate that design revisions can affect diesel exhaust. Carbon monoxide and sulfur dioxide are discussed and the effect of design revisions on aldehydes, oxides of nitrogen, and hydrocarbons are illustrated. The effects of the design revisions on exhaust smoke and odor are compared using three different measurement techniques. Smoke is compared using a filtering meter on engine dynamometer tests, a sampling light extinction meter on road tests, and a full flow light extinction meter on chassis dynamometer tests. Odor is compared using a sniff-box technique and a psychological scale, a threshold technique using natural dilution in a large building, and a sniff tube-dilution technique using the Turk bottle rating.
1968-02-01
Technical Paper
680421
J. M. Perez, E. W. Landen
Diesel engine exhaust emission characteristics vary considerably with the overall design of the combustion and fuel injection systems. Emission measurements were made on total hydrocarbons, nitrogen oxides, carbon monoxide, carbon dioxide, and smoke. The hydrocarbon measurements of the precombustion chamber engine are considerably lower than the direct injection engine. Less than five pounds of total hydrocarbons per 1000 gal of fuel are produced at rated conditions by all precombustion chamber engines studied. Precombustion chamber engines produce smaller quantities of the oxides of nitrogen when compared to direct injection engines. All diesels produced low carbon monoxide emissions. A novel technique for qualitative and quantitative evaluation of diesel exhaust odors is introduced. Exhaust odor intensity from the precombustion chamber engine is much less than that from the direct injection engine.
1968-02-01
Technical Paper
680431
Manfred Altman, Thomas H. Floyd
This study was concerned with establishment of criteria for urban automobiles. The benefits looked for were a significant reduction of street congestion, air pollution, and required land allocation. It was determined that one possible and attractive answer was a vehicle on the order of 9 ft in length, seating three passengers side by side, and powered with a “hybrid” internal combustion and battery system. This paper presents the justification for these choices, and lays the foundation for a later one covering the results of a systems evaluation of fleet operation.
1968-02-01
Technical Paper
680400
W. F. Deeter, H. D. Daigh, O. W. Wallin
Using 1966 and later model vehicles equipped with crankcase and exhaust hydrocarbon and carbon monoxide controls, prototype systems were installed to control evaporative emissions from the tank and carburetor and nitrogen oxides in the exhaust. The systems selected were the ARCO vehicle vapor recovery, and the nitric oxide reduction. Baseline evaporative emissions were determined for two of the vehicles operated over-the-road and on the chassis dynamometer. The proposed federal evaporation loss test technique was used for evaluating the performance of the vehicle vapor recovery system. Evaporation losses from the equipped vehicles were less than 1 g per test -- well below the proposed federal standard of 6g. However, carbon monoxide in the exhaust from one car increased by approximately 0.1%. The system had no effect on exhaust hydrocarbons. The mechanism by which the vehicle vapor recovery system functions was investigated briefly.
1968-02-01
Technical Paper
680401
R. F. Sawyer, E. S. Starkman, L Muzio, W. L. Schmidt
A single cylinder investigation was conducted to determine concentration of oxides of nitrogen resulting from combustion of ammonia and air in a spark ignition engine over a range of fuel-air ratios typical of normal engine operation with ammonia. Nitric oxide concentrations exceeded that with hydrocarbons. Spectroscopic observations during the expansion process gave concentrations in some instances an order of magnitude greater than exhaust gas determinations. The results imply a different mechanism for nitric oxide formation with ammonia fuel than with hydrocarbons and that some equilibrating process may take place between combustion and exhaust to reduce otherwise even greater than measured exhaust gas concentrations.
1968-02-01
Technical Paper
680402
M. W. Korth, A. H. Rose
Exhaust emissions were measured from a Chrysler gas turbine automobile operating on the road and on the dynamometer. Two different fuels were used, and tests were made after both hot and cold starts. Exhaust emissions, measured both as mass and as concentration, were considerably lower than those from a conventional automobile. Composition of the hydrocarbon emissions generally reflected the structure of the fuel being burned.
1968-02-01
Technical Paper
680769
R. C. Lee, D. B. Wimmer
Differences in the power producing capacities and exhaust emission characteristics of various spark-ignition-engine fuels are frequently obscured by interactions involving the particular engine system used in the comparison. In an attempt to minimize this problem, gasoline, propane, methane, and a hydrogen-methane fuel gas were compared in a single cylinder engine under conditions that were optimum for each fuel. The resulting data, coupled with an estimated duty cycle representative of traffic service, permitted the development of internally comparable data on fuel consumption and exhaust emissions. Smog-inducing hydrocarbon emissions from the exhaust of a propane-fueled engine can be less than 13% of the minimum value obtainable with a gasoline fueled engine. Such emissions would be substantially eliminated with a well designed methane engine.
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