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Bradow, Ronald L.
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Simulation of Automobile Brake Wear Dynamics and Estimation of Emissions

Northrop Services, Inc. Research Triangle Park, NC-Soyoung Cha, Philip Carter
U.S. Environmental Protection Agency Research Triangle Park, NC-Ronald L. Bradow
Published 1983-06-06 by SAE International in United States
Asbestos emissions from automobile brakes were measured under conditions simulating downtown city driving. Reference data for city driving was obtained by measuring vehicle speed, time of brake application, cool-down time between applications, brake hydraulic-line pressure and pad temperature. Data from 1800 braking applications were then analyzed to provide a statistical distribution of representative braking cycles.We constructed a computer-controlled brake emission test rig that simulated road braking operation of a front wheel disc brake and collected airborne wear debris. Representative braking cycles were programmed on this system to experimentally estimate brake emissions under a variety of braking conditions.Realistic braking operations produced particle and asbestos emission rates in close agreement with those measured by Williams and Muhlbaier. Asbestos concentration was not correlated with mechanical work done in braking.Application of the asbestos emission rates to air quality models confirmed Williams and Muhlbaier's finding that about 1% of asbestos fibers in city core districts originated from disc brake wear.
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Automotive Emissions of Ethylene Dibromide

Northrop Services Inc.-John M. Lang
U.S. Environmental Protection Agency, R.T.P., NC-John E. Sigsby, David L. Dropkin, Ronald L. Bradow
Published 1982-02-01 by SAE International in United States
Ethylene dibromide, a suspected carcinogen, and ethylene dichloride are commonly used in leaded gasoline as scavengers. Ethylene dibromide emission rates were determined from seven automobiles which had a wide range of control devices, ranging from totally uncontrolled to evaporative and catalytic emission controls. The vehicles were operated over a variety of cycles to simulate the normally encountered range of driving conditions. Evaporative losses were also measured. Tailpipe emission rates varied from 0 to 1300 micrograms ethylene dibromide per mile depending upon the control devices present and the operating cycle. Evaporative emission of ethylene dibromide ranged from 0.03 to 0.4 micrograms per mile equivalent. Emission of other lead-related compounds were sought but not found.The consequences of using leaded fuels in vehicles equipped with catalysts was investigated. Emission rates of ethylene dibromide increased with usage and appeared to depend on catalyst activity.Overall emission rates of ethylene dibromide correlated with hydrocarbon emission rates.
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Sampling Diesel Engine Particle and Artifacts from Nitrogen Oxide Interactions

Environmental Protection Agency, Environmental Sciences Research Lab.-Ronald L. Bradow, Roy B. Zweidinger, Frank M. Black
Southwest Research Institute, San Antonio, TX-Harry M. Dietzmann
Published 1982-02-01 by SAE International in United States
The possibility that NO2 artifactually converts polynuclear aromatic hydrocarbons to biologically active species in diesel particle sampling is explored. NO2 was injected into dilution air upstream of the exhaust mixing point at varvinq concentra-ting levels with both passenger car and truck driving simulations. Ames test specific activity and nitropyrene levels were seen to increase above base levels when the NO2 level exceeded 5 to 10 ppm. Extract responses to added NO2 in transient drivinq appeared to initially increase, then level off above about 20 ppm. It is suggested that some requestering of nitratable orqan-ics may be responsible. Reexposure of filtered particles to diluted gas phase diesel exhaust caused little increase in nitroaromatics or Ames activitv. It appears that NO2 levels below about 5 ppm are relatively safe from filter artifacts.
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Refrigerant 12 Leakage in Automobile Air Conditioner Systems

Thomas Lemmons, Ronald L. Bradow
Published 1981-02-01 by SAE International in United States
The paper presents measurements of whole vehicle refrigerant 12 leakage from a varied fleet of U.S. manufactured passenger automobiles in addition to measurements of some individual leak sources within the operating vehicles. Evaluation of Halogen leak detectors and of an R-12 refrigerant, Dytel, are also made with a view to determining their sensitivity or adequacy in detecting refrigerant leaks in operating automotive air conditioning systems. Recommendations regarding desirability of improvements in service, maintenance and system design to reduce R-12 emission levels are also presented.
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Emissions from Trucks by Chassis Version of 1983 Transient Procedure

Southwest Research Institute-Harry E. Dietzmann, Mary Ann Parness
U. S. Environmental Protection Agency-Ronald L. Bradow
Published 1980-10-01 by SAE International in United States
Regulated gaseous, particulate and several unregulated emissions are reported from four heavy-duty diesel engines operated on the chassis version of the 1983 transient procedure. Emissions were obtained from Caterpillar 3208, Mack ENDT 676, Cummins Formula 290 and Detroit Diesel 8V-71 engines with several diesel fuels. A large dilution tunnel (57′ × 46″ ID) was fabricated to allow total exhaust dilution, rather than the double dilution employed in the stationary engine version of the transient procedure. A modal particulate sampler was developed to obtain particulate data from the individual segments of the 1983 transient procedure. The exhaust gas was analyzed for benzo(a)pyrene, metals, N2O, NO2, individual hydrocarbons and HCN. Sequential extractions were performed and measured versus calculated fuel consumptions were obtained.
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Characterization of Heavy - Duty Diesel Gaseous and Particulate Emissions, and Effects of Fuel Composition

Southwest Research Inst.-Charles T. Hare
U.S. Environmental Protection Agency-Ronald L. Bradow
Published 1979-02-01 by SAE International in United States
Gaseous and particulate emissions from two heavy-duty diesel engines were characterized while the engines were operated on five different fuels. Characterization included mass rates of major exhaust products, plus analysis of particulate matter for sulfate, trace elements, major elements, total solubles, and other properties.Analysis of rate and composition data was conducted with regard to fuel and engine effects on particulate. Two large particulate samples were also collected for later analysis on groups of organics present.
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Unregulated Emissions from Three-Way Catalyst Cars

U.S. Environmental Protection Agency-Ronald L. Bradow, Fred D. Stump
Published 1977-02-01 by SAE International in United States
In response to more stringent emission requirements, catalysts for reducing NO to molecular nitrogen were developed. One of the most promising of these, the three-way catalyst, has been the subject of an EPA study to determine if it produces new tailpipe contaminants. This study and its results are described.
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Light-Duty Diesel Emission Correction Factors for Ambient Conditions

Southwest Research Institute-Charles T. Hare
U.S. Environmental Protection Agency-Ronald L. Bradow
Published 1977-02-01 by SAE International in United States
To determine the effects of ambient conditions on emissions from light-duty diesels, 174 emission tests were conducted on four vehicles. The major program objective was estimation of a factor to correct NOx emissions to a standard humidity. Other emissions and ambient conditions were also examined for relationships by regression analysis.Humidity effects on NOx emissions were found to be substantial and quite predictable. Relationships observed between other emissions and ambient conditions were relatively weak and unpredictable. Several types of NOx-humidity correction factors were estimated and compared to those already used for other vehicle and engine classes.
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A Characterization of Exhaust Emissions from Lean Burn, Rotary, and Stratified Charge Engines

Environmental Protection Agency-Peter A. Gabele, James N. Braddock, Ronald L. Bradow
Published 1977-02-01 by SAE International in United States
This paper reports the results of an exhaust emissions characterization from the non-catalyst control systems employed on the Mazda RX-4 rotary, the Honda CVCC, and the Chrysler electronic lean burn. Throughout the paper, exhaust emissions from these vehicles are compared to those from a Chrysler equipped with an oxidation catalyst and an air pump. The emissions characterized are carbon monoxide, hydrocarbons, nitrogen oxides, sulfur dioxide, sulfates, hydrogen sulfide, carbonyl sulfide, hydrogen cyanide, aldehydes, particulate matter, and detailed hydrocarbons. A brief description of the sampling and analysis procedures used is included within the discussion.
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Fuel and Additive Effects on Diesel Particulate-Development and Demonstration of Methodology

Southwest Research Institute-Charles T. Hare, Karl J. Springer
U.S. Enviromental Protection Agency-Ronald L. Bradow
Published 1976-02-01 by SAE International in United States
To develop a methodology for characterizing particulate emissions from diesel engines, one 2-stroke cycle engine and one 4-stroke cycle engine were operated in both individual steady-state modes and according to a variation of the 13-mode diesel emissions measurement procedure. Both engines were operated on three fuels, each used with one of two available diesel fuel additives as well as by itself.The primary particulate sampling technique employed was a dilution tunnel, and secondary evaluation techniques included a diluter-sampler developed under contract to EPA by another organization, a light extinction smokemeter, and a filter-type sampling smokemeter. Gaseous emissions were also measured, providing a running check on engine condition.Particulate mass rates were calculated from gravimetric data; and analysis of particulate included determination of sulfur, carbon, hydrogen, nitrogen, phenols, nitrosamines, trace metals, and organic solubles. Analysis of the organic soluble fraction included NMR, IR, paraffin boiling point distribution, benz(a)pyrene, sulfur, carbon, hydrogen, nitrogen, and oxygen.The results of this study are the first of their type to be widely distributed, so it is imperative that the use of emissions values…
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