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Due to its high efficiency and superior durability the diesel engine is again becoming a prime candidate for future light-duty vehicle applications within the United States. While in Europe the overall diesel share exceeds 40%, the current diesel share in the U.S. is 1%. Despite the current situation and the very stringent Tier 2 emission standards, efforts are being made to introduce the diesel engine back into the U.S. market. In order to succeed, these vehicles have to comply with emissions standards over a 120,000 miles distance while maintaining their excellent fuel economy. The availability of technologies such as high-pressure common-rail fuel systems, low sulfur diesel fuel, NOx adsorber catalysts (NAC), and diesel particle filters (DPFs) allow the development of powertrain systems that have the potential to comply with the light-duty Tier 2 emission requirements. In support of this, the U.S.

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 report describes in detail new test procedures designed to minimize test variability, and the resulting false failures of new technology vehicles. There are currently six promulgated test procedures. The new procedures differ from the current ones in that they include controlled preconditioning, second chance testing, and sampling and score selecting algorithms. These are intended to minimize the variability in testing conditions and thereby reduce false failures of clean vehicles. High emitting vehicles which have been escaping detection with the current test procedures may continue to do so under the new ones. It is EPA's hope that these new procedures will improve the possibility of using more stringent cutpoints and non-idle test modes in the future to detect these high emitters by eliminating the additional false failures that would otherwise occur by instituting such measures under current procedures.

The use of a partial flow sampling system (PFSS) to measure nonroad steady-state diesel engine particulate matter (PM) emissions is a technique for certification approved by a number of regulatory agencies around the world including the US EPA. Recently, there have been proposals to change future nonroad tests to include testing over a nonroad transient cycle. PFSS units that can quantify PM over the transient cycle have also been discussed. The full flow constant volume sampling (CVS) technique has been the standard method for collecting PM under transient engine operation. It is expensive and requires large facilities as compared to a typical PFSS. Despite the need for a cheaper alternative to the CVS, there has been a concern regarding how well the PM measured using a PFSS compared to that measured by the CVS. In this study, three PFSS units, including AVL SPC, Horiba MDLT, and Sierra BG-2 were investigated in parallel with a full flow CVS.

The potential discrepancy between the fuel economy shown on new vehicle labels and that achieved by consumers has been receiving increased attention of late. EPA has not modified its labeling procedures since 1985. It is likely possible that driving patterns in the U.S. have changed since that time. One possible modification to the labeling procedures is to incorporate the fuel economy measured over the emission certification tests not currently used in deriving the fuel economy label (i.e., the US06 high speed and aggressive driving test, the SC03 air conditioning test and the cold temperature test). This paper focuses on the US06 cycle and the possible incorporation of aggressive driving into the fuel economy label. As part of its development of the successor to the MOBILE emissions model, the Motor Vehicle Emission Modeling System (MOVES), EPA has developed a physically-based model of emissions and fuel consumption which accounts for different driving patterns.

The United States Environmental Protection Agency (EPA) has initiated Phase I of a regulatory program to control exhaust emissions of nonroad diesel engines over 37 kW. Central to any emissions regulation is the test procedure, which must include an appropriate test cycle. Based on actual in-use speed and estimated torque data collected from an agricultural tractor, a backhoe-loader, and a crawler tractor, three duty cycles were developed. Using an iterative process, comparison of chi-square statistical data was used to identify representative microtrips, segments of engine operation gathered during performance of selected activities. Representative microtrips for specific activities for a particular nonroad application were “strung” together to make up a test cycle. Before accepting the test cycle, data for the cycle was compared to statistical data used to characterize the raw data in an effort to validate that the cycle was representative of the raw data.

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.

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.

Six in-use vehicles were tested on a baseline gasoline and nine gasoline/ethanol blends to determine the effect of ethanol content in fuels on automotive exhaust emissions and fuel economy. The baseline gasoline was representative of average summer gasoline and served as the base from which the other fuels were blended. For the majority of the vehicles, total hydrocarbon, and carbon monoxide exhaust emissions as well as fuel economy decreased while NOx and acetaldehyde exhaust emissions increased as the ethanol content in the test fuel increased. Formaldehyde and carbon dioxide emissions were relatively unaffected by the addition of ethanol. The emission responses to the increased fuel oxygen levels were consistent with what would be expected from leaning-out the air/fuel ratio for a spark ignition engine. The results are shown graphically and a linear regression is performed utilizing the method of least squares to investigate statistically significant trends in the data.

In the 1990's there will be a different mix of vehicle technologies than existed in the late 1970's when inspection/Maintenance (I/M) programs were first mandated. These changes include the widespread use of “closed-loop” computer control of engine parameters and fuel injection. Several studies by EPA are examined to determine the effect of these changes on existing I/M programs and to investigate new methods of vehicle inspection. The report discusses the effectiveness of a standard idle emission test versus other inspection methods, the role of proper preconditioning, self-diagnostic trouble code checks as a method to identify high emitting vehicles, uncertainties in predicting tampering and misfueling rates for the future, problems with decentralized programs, and the effectiveness of I/M repairs in reducing vehicle emissions as measured on the Federal Test Procedure.

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.

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.

Reducing aerodynamic drag and tire rolling resistance in trucks using cooled EGR engines meeting EPA 2004 emissions standards has been observed to result in increases in fuel economy and decreases in NOx emissions. We report here on tests conducted using vehicles equipped a non-EGR engine meeting EPA 2004 emission standards and an electronically-controlled engine meeting EPA 1998 emissions standards. The effects of trailer fairings and single-wide tires on fuel economy and NOx emissions were tested using SAE test procedure J1321. NOx emissions were measured using a portable emissions monitoring system (PEMS). Fuel consumption was estimated by a carbon balance on PEMS output and by the gravimetric method specified by test procedure J1321. Fuel consumption decreased and fuel economy increased by a maximum of about 10 percent, and NOx emissions decreased by a maximum of 20 percent relative to baseline.

FTP-UDDS (urban dynamometer driving schedule) exhaust particulate matter (PM) emission rates were determined for 361 light-duty gasoline (LDGV) and 49 diesel passenger vehicles ranging in model year (MY) from 1965 to 1997. LDGVs were recruited into four MY categories. In addition, special effort was made to recruit LDGVs with visible smoke emissions, since these vehicles may be significant contributors to the mobile source PM emission inventory. Both light and heavy-duty diesels where included in the passenger diesel test fleet, which was insufficient in size to separate into the same MY categories as the LDGVs. Vehicles were tested as-received in three areas: Denver, Colorado; San Antonio, Texas; and the South Coast Air Quality Management District, California. The average PM emission rates were 3.3, 79.9, 384 and 558 mg/mi for 1991-97 MY LDGVs, pre-1981 LDGVs, smoking LDGVs and the diesel vehicles, respectively.

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.

The Schatz Heat Battery stores excess heat energy from the engine cooling system during vehicle operation. This excess energy may be returned to the coolant upon the ensuing cold start, shortening the engine warm-up period and decreasing cold start related emissions of unburned fuel and carbon monoxide (CO). A Heat Battery was evaluated on a test vehicle to determine its effect on unburned fuel emissions, CO emissions, and fuel economy over the cold start portion (Bag 1) of the Federal Test Procedure (FTP) at 24°C and -7°C ambient conditions. The Heat Battery was mounted in a vehicle fueled alternately with indolene clear (unleaded gasoline) and M85 high methanol blend fuels. Several Heat Battery/coolant flow configurations were evaluated to determine which would result in lowest cold start emissions.

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.

Current SAE practices for evaluating potential improvements in fuel economy on heavy-duty vehicles rely on gravimetric measurements of fuel tanks. However, the recent evolution of portable emissions measurement systems (PEMS) offers an alternative means of evaluating real-world fuel economy that may be faster and more cost effective. This paper provides a direct comparison of these two methods based on a recent EPA study conducted at Southwest Research Institute. More than 228 on-road tests were performed on two pairs of class 8 tractor-trailers according to SAE test procedure J1321 in an assessment of various chassis components designed to reduce drag losses on the vehicle. During these tests, SEMTECH-D™ portable emissions measurement systems from Sensor's, Incorporated were operating in each of the vehicles to evaluate emissions and to provide a redundant measure of fuel economy.

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.

We hypothesize that components designed to improve fuel economy by reducing power requirements should also result in a decrease in emissions of oxides of nitrogen (NOx). Fuel economy and NOx emissions of a pair of class 8 tractor-trailers were measured on a test track to evaluate the effects of single wide tires and trailer aerodynamic devices. Fuel economy was measured using a modified version of SAE test procedure J1321. NOx emissions were measured using a portable emissions monitoring system (PEMS). Fuel consumption was estimated by a carbon balance on PEMS output and correlated to fuel meter measurements. Tests were conducted using drive cycles simulating highway operations at 55 mph and 65 mph and suburban stop-and-go traffic. The tests showed a negative correlation (significant at p < 0.05) between fuel economy and NOx emissions. Single wide tires and trailer aerodynamic devices resulted in increased fuel economy and decreased NOx emissions relative to the baseline tests.