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Studies of emissions from vehicles equipped with catalysts have shown that some unregulated emissions can increase when a catalyst is used. One example of this is sulfuric acid, which has been studied extensively. Other unregulated emissions include ammonia and hydrogen cyanide. In a number of studies, these unregulated pollutant emissions have been measured from light-duty vehicles and heavy-duty engines. These emission levels were used in air quality dispersion models to predict the resultant air quality levels. The ambient concentrations predicted for each pollutant were then compared to suggested concentrations at which adverse health effects may be found to determine if additional monitoring or control would be indicated for these pollutants. It was determined that mobile source emissions of sulfuric acid, hydrogen cyanide, and ammonia do not in general result in ambient levels of concern for the air quality situations studied.

This, the eleventh in a series of Papers on EPA fuel economy trends, emphasizes the current Model Year (1983) as usual, but also gives increased emphasis to trends in vehicle technology, including catalyst and transmission subclasses. Final “CAFE”* production volumes and MPG figures have been used to update the data bases through the 1980 Model Year, and an analytic method used in the past to allocate year-to-year fleet MPG changes to specific causes, such as weight mix shifts, has been reinstituted. Conclusions are presented on the relation between fuel economy and emission standards, catalyst types, and transmission types.

This paper presents the results of several emission testing programs conducted by the U.S. Environmental Protection Agency. The test vehicles were primarily 1980 and 1981 passenger cars which were obtained at random from private owners. Some 1982 models were also tested. The 1328 vehicles were selected from the Los Angeles area as well as from a number of other low-altitude locations. The test sequence included the Federal Test Procedure, the Highway Fuel Economy Test and several short cycle tests. The primary purpose of the program was to gather information on current vehicles which could be used in calculations and projections of air quality and aid development of programs to improve it. The results of the program indicate that these vehicles are capable of maintaining low emission levels although high levels are also possible due to defects, deterioration, or tampering. Inspection/Maintenance programs are a feasible and effective means for correcting high levels when they occur.

EPA Fuel economy figures are presented for model year 1982 cars and light duty trucks. Comparisons with the MPG figures of prior years are included. Sales penetrations of various vehicle, engine, and emission control design features are given, and domestic cars' MPG characteristics are compared to that of imports', gasoline vehicle MPG is compared to Diesel MPG, and 49-states MPG is compared to California MPG. Usage of newer vehicle technologies is continuing to increase, leading to continued growth in fuel economy capability in spite of stringent emission standards.

This report describes an evaluation of fuel economy of in-use passenger cars conducted by the U.S. Environmental Protection Agency during 1980. A total of 440 vehicles from the 1975-1980 model years were obtained from private owners in several cities. Each vehicle was tested according to the Federal Test Procedure and the Highway Fuel Economy Test. After the laboratory testing, the owners were asked to record their next four fuel purchases on a reply postcard. The results from the survey were analyzed and compared with the test results, estimates by the owner, and the values published in EPA's Gas Mileage Guide.

EPA new-model fuel economy figures are presented for passenger vehicles and light duty trucks (those with GVW ratings up to 8500 lbs). The 1981 models are emphasized, with some comparisons to prior years included. Reader familiarity with the EPA tests, data bases, and analytical methods is assumed. Principal two-way analyses include comparisons of domestic vs. import, gasoline vs. Diesel, and Federal (49-state) vs. California vehicles. Sales fractions for a number of vehicle and engine emission control design features are included. The principal finding is that increased use of newer vehicle and emission control technologies in 1981 has accompanied significant fuel economy gains in spite of the tougher 1981 emission standards.

This paper presents the results of an exhaust emission testing program conducted by the U.S. Environmental Protection Agency. The test vehicles were 1978–1980 passenger cars of various makes and models. Each of the 686 vehicles tested was equipped with a three-way catalyst system and was certified to California standards. The purpose of the program was to gather information on current systems in customer use for projections on the ability of the three-way system to meet emission standards of the future. The results indicate that these systems are capable of achieving low emission levels although high levels are also possible due to defects, deterioration, or tampering.

This paper summarizes a laboratory effort toward reducing nine-mode cycle composite emissions and fuel consumption in a heavy-duty gasoline engine, while retaining current durability performance. Evaluations involved standard carburetors, a Dresserator inductor, a Bendix electronic fuel injection system, exhaust manifold thermal reactors, and exhaust gas recirculation, along with other components and engine operating parameters. A system consisting of electronic fuel injection, thermal reactors with air injection and exhaust gas recirculation, was assembled which met specified project goals. An oxidation catalyst was included as an add-on during the service accumulation demonstration. In addition, the driveability of this engine configuration was demonstrated.

Comparison of vehicle thermal efficiency and engine load factor for 1977 and 1978 model year certification vehicles shows low correlation. At any load factor, the spread in thermal efficiencies was on the order of 2 to 1. These facts suggest that, with existing technologies, vehicle manufacturers can realize a significant improvement in fuel economy through better matching of engines (specific fuel consumption), transmissions and final drive ratios to vehicle power requirements.

High mileage vehicles (in excess of 50,000 miles) contribute more than half of all vehicular emissions. With the new catalytic converter equipped cars, the proportional contribution of these vehicles may be even higher than for pre-catalyst vehicles. Thus a substantial portion of motor vehicle related air pollution may be caused by vehicles not subject to the manufacturer directed provisions of the Clean Air Act. This paper presents a modeling effort based on hypotheses and some preliminary data, and suggests some alternatives to combat this potential problem.

The advent of emission control technology has resulted in significant changes in both the total mass and detailed patterns of hydrocarbons emitted from automobiles. Emission rates of 56 hydrocarbons from 22 motor vehicles, including catalyst and noncatalyst configurations, were determined for the Federal Urban Driving Cycle. An increased relative abundance of methane is indicated for vehicles equipped with oxidation catalysts. In view of the photochemically non-reactive nature of methane, simple and economic procedures for determination of vehicle nonmethane hydrocarbon emission rates are evaluated. In general the procedures evaluated require independent total hydrocarbon and methane analysis, with the nonmethane hydrocarbon level calculated by difference. The procedures are evaluated by comparison of indicated nonmethane hydrocarbon emission rates with rates obtained by summation of individual compound rates determined by advanced gas chromatographic procedures.

A simple, inexpensive, critical flow blender has been developed for filling a tedlar bag with controllable concentrations of HC, NOx, CO2, and CO gases at levels encountered in automobile emissions testing. According to a daily schedule, a technician takes the bag to all analyzer sites in the laboratory for analysis. The concentrations indicated by each site are compared to the overall averages. The results are stored in a computerized data base from which control charts, statistical analyses, and interpretations of significant differences among test sites can be made. The precision, accuracy, and statistical interpretations of the data are discussed.

An experimental program was conducted to characterize the gaseous and particulate emissions from a 1975 Peugeot 504D light duty diesel-powered vehicle. The vehicle was tested over the 1975 Federal Test Procedure, Highway Fuel Economy Test, and Sulfate Emissions Test driving cycles using four different fuels covering a fair range of composition, density, and sulfur content. In addition to fuel economy and regulated gaseous emission measurements of hydrocarbons, carbon monoxide, and oxides of nitrogen, emission measurements were also obtained for non-regulated pollutants including sulfur dioxide, sulfates, aldehydes, benzo[a]pyrene, carbonyl sulfide, hydrogen cyanide, nonreactive hydrocarbons, and particulate matter. The results are discussed in terms of emission trends due to either fuel type or driving cycle influence.

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.

This paper discusses the systems used by the Office of Mobile Source Air Pollution Control of EPA to measure and analyze automotive sulfuric acid emissions. This system involves mixing the entire vehicle exhaust with dilution air in a dilution tunnel. Sulfuric acid samples are collected by passing a small portion of the dilute exhaust through Fluoropore filters. The sulfuric acid content of the filters is determined by an automated barium chloranilate method. This paper also discusses test results from a number of advanced prototype vehicles including two stratified charge cars, a Dresser carburetor vehicle, three dual catalyst cars, and a 3-way catalyst car.

Methylcyclopentadienylmanganese tricarbonyl (MMT) while originally marketed in the late 50's and early 60's as a secondary antiknock to leaded fuels, is presently being marketed as a primary antiknock targeted for the EPA required lead-free gasoline grade tailored for use in catalyst-equipped vehicles. This paper reviews and discusses new information related to the effect of manganese gasoline additives on the performance of catalysts, regulated emissions, and several currently unregulated emissions. In addition, estimates of human exposures to automotive-generated manganese particulate and the toxicological characteristics of manganese are discussed as they related to an assessment of the potential public health consequences should manganese additives come into widespread use. EPA's position regarding the use of manganese additives is presented and discussed.

This is a summary compilation and analysis of exhaust-emission results and operating parameters from forty-five heavy-duty gasoline and diesel-powered vehicles tested over a 7.24-mile road course known as the San Antonio Road Route (SARR); and, for correlative purposes, on a chassis dynamometer.(2) Exhaust samples were collected and analyzed using the Constant Volume Sampler (CVS) technique similar to that used in emission testing of light-duty vehicles. On the road course, all equipment and instrumentation were located on the vehicle while electrical power was supplied by a trailer-mounted generator. In addition to exhaust emissions, operating parameters such as vehicle speed, engine speed, manifold vacuum, and transmission gear were simultaneously measured and recorded on magnetic tape. The forty-five vehicles tested represent various model years, GVW ratings, and engine types and sizes.