Several gasoline supply companies have introduced versions of reformulated gasolines to gain experience in manufacturing, transporting, and marketing this new type of gasoline while providing environmental benefits. This paper describes the evaluation of one such reformulated gasoline on a variety of engine and vehicle technologies. The reformulated gasoline tested in this program is marketed exclusively in the metropolitan St. Louis area. Thus, a side-by-side comparison of fuels representing the average gasoline sold in St. Louis and the reformulated gasoline was made. The reformulated gasoline was blended at the limits of established manufacturing specifications to provide a conservative estimate of the environmental benefits of such a fuel. Emissions and driveability performance of both fuels were tested in cars representing four distinct vehicle technologies. The technology classes represented were non-catalyst, open loop oxidation catalyst, closed loop non-adaptive three-way catalyst, and adaptive learning three-way catalyst equipped vehicles. A total of eight vehicles was tested ranging in model years from 1973 to 1989. The standard Federal Test Procedure with a modified preparation cycle was employed to evaluate the vehicle emission response. Exhaust and evaporative emission measurements were made with complete hydrocarbon speciation and toxic identification. Results of the comparative testing indicated significant reductions of carbon monoxide, total hydrocarbons, oxides of nitrogen, benzene and 1,3 butadiene in 1980 and newer vehicles. Older vehicles (pre-1980) also showed significant reductions of diurnal evaporative hydrocarbon emissions, carbon monoxide, oxides of nitrogen and benzene but increases in hot soak hydrocarbon emissions. All cars showed increases in formaldehyde emissions with the older cars also showing increases in acetaldehyde. The data were used to model the impact of this new gasoline formulation on the St. Louis metropolitan area. The Environmental Protection Agency's MOBILE4 inventory model was employed to project benefits for the years 1995 and 2005 should all gasoline sold in the St. Louis area be the tested reformulated gasoline.

Schoonveld, Gary A., Marshall, William F.

Performance of Activated Carbon in Evaporative Loss Control Systems

90211910/1/1990

Although activated carbons have been used successfully for approximately 20 years for control of hydrocarbon evaporative emissions from motor vehicles, the correlation of fundamental activated carbon properties, molecular scale pore size/volume characteristics, to carbon performance has not generally been available. Improvements in wood-based carbon have focused on the pore size/volume characteristics resulting in a doubling of performance, as measured by butane working capacity, over the past few years. In addition to relating the butane working capacity for different types of carbon to pore characteristics, laboratory studies using new carbons have demonstrated that the capacity for adsorption of vapors from gasoline is also related to this fundamental property. Furthermore, different types of in-use carbons from vehicle canisters have been evaluated to confirm that the key to carbon performance is pore characteristics and also, that laboratory evaluations of carbons, using proper conditions, can realistically simulate the performance of actual in-use carbons.

Johnson, H.R., Williams, R.S.

Improved Design of Onboard Control of Refueling Emissions

9001552/1/1990

Onboard refueling control technology has been successfully applied to two vehicles with 98+% efficiency in tests with 10.5 RVP fuel at 84° F. The Onboard system, which controls exhaust, evaporative, refueling, and so called “running losses”, was constructed out of components found in current automotive evaporative control systems. During refueling, the tank vapors are forced into the enhanced charcoal canister by a flowing liquid seal in the fillpipe. The canister was removed from the engine compartment and mounted within the vehicle frame close to the fuel tank. Each vehicle demonstrates a different possible safe location from a crash worthiness viewpoint. In order to further improve safety by preventing the expulsion of liquid gasoline upon gas cap removal, the orifices in the production tank vent lines were removed so that the fuel tank is at atmospheric pressure at all times. As modified, no significant driveability differences from production vehicles were found. Both the production and onboard vehicles met current exhaust and evaporative standards. In addition, results of laboratory simulated rollover tests showed zero fuel spillage.

Musser, George S., Shannon, Hugh F., Hochhauser, Albert M.

Factors Affecting the Design and Breakthrough Performance of Evaporative Loss Control Systems for Current and Future Emission Standards

8906212/1/1989

For approximately 20 years, activated carbons used in motor vehicle evaporative loss control devices [ELCD] have been selected on the basis of butane saturation working capacity. While this technique served as a useful standard in the past, more stringent evaporative emission regulations coupled with changing automobile designs and changes in gasoline composition have prompted a reexamination of the carbon products used in the ELCD systems and the methods used to predict the carbon performance. Our studies have shown the butane working capacity test to be misleading, and a poor indicator of actual performance. In contrast, a new adsorbent test rig that measures carbon working capacity to breakthrough has been found to be a much more sensitive measurement of a carbon's suitability for meeting the 2 gram SHED emission test.

Urbanic, J. E., Oswald, E. S., Wagner, N. J., Moore, H. E.

Global Trends in Motor Vehicle Pollution Control - A 1988 Perspective

8905812/1/1989

The purpose of this paper is to review and summarize recent trends around the world regarding motor vehicle pollution control. It shows the persistence of and in some cases worsening of motor vehicle related pollution problems, the increasing spread of advanced pollution control technologies including catalytic converters to address these problems, and the push to extend the capability of these advanced technologies to attain even lower pollution levels under a greater variety of actual operating conditions. As the global vehicle population continues to grow, the impact on global warming is assessed.

Walsh, Michael P.

Evaporative Emissions from Modern European Vehicles and Their Control

880315

2/1/1988

Evaporative emission levels have been determined in a CONCAWE* programme for a range of ten uncontrolled European vehicles using a modified SHED test procedure as developed by the CEC*. Three extra vehicles were tested which were equipped with evaporative and exhaust emission control systems, but of the same make and model as three of the uncontrolled test cars. The vehicles were tested using several warm-up cycles and on a range of fuels whose volatility parameters were independently varied, including oxygenate blends. Exhaust emissions were determined and a few measurements of true diurnal emissions carried out. Vehicle fuel system design had the greatest effect on evaporative emissions which varied between 4 to 16 g/test on a typical European summer fuel. Gasoline volatility had a significant but smaller effect and RVP was shown to be the dominant fuel parameter. At the same volatility, oxygenate blends gave similar or lower emissions than hydrocarbon fuels. Hot-soak and running losses increased significantly with increasing warm-up cycle severity. True diurnal emissions were found to be significant and of similar magnitude to combined hot-soak and running losses. The carbon canister emission control systems tested were very effective and reduced emissions by up to 85 per cent.

McArragher, J. S., Betts, W. E., Brandt, J., Kiessfing, D., Marchesi, G. F., Owen, K., Pearson, J. K., Schug, K. P., Sneigrove, D. G.

Factors Influencing the Composition and Quantity of Passenger Car Refueling Emissions-Part II

880712

2/1/1988

Refueling emissions from a 1986 Pontiac Grand Am were characterized using 3 test fuels, including a winter, summer and intermediate blend gasoline under a variety of seasonal temperature conditions. The effects of varying fuel volatility (10.1 to 13.3 psi RVP), dispensed fuel temperature (50 to 88°F), and vehicle tank fuel temperature (40 to 108°F), were investigated. Hydrocarbon (HC) emissions ranged from 2.90 to 7.41 grams per gallon of delivered fuel. Detailed hydrocarbon analyses were completed for both the test fuels (dispensed fuel and tank fuel) and the refueling emissions. The average (all test fuels and temperature scenarios) test gasoline composition was 46.1% paraffins, 6.3% olefins, 45.2% aromatics, with an average carbon number of 7.42; the average HC emission rate was 4.69 g/gal; and the average emissions composition was 81.4% paraffins, 12.2% olefins, 5.4% aromatics, with an average carbon number of 4.79. Butanes and pentanes comprised about 70% of the total HC refueling emissions.

Braddock, James N.

Emission Factor Data Base for Prototype Light-Duty Methanol Vehicles

87205511/1/1987

Exhaust and evaporative emissions data for prototype and first generation light-duty methanol-fueled vehicles have been compiled from a number of different sources into three different data bases (exhaust city and highway, exhaust idle, and evaporative emissions) along with qualitative data on the vehicles and test programs. This paper describes the structure of each data base and presents the results of a limited statistical evaluation of the data. The data themselves are also made available. EPA's methodology in utilizing the data to evaluate the environmental effects of a transition to methanol fuel is discussed and suggestions for further vehicle testing and statistical analyses of the data are provided. It is hoped that this paper will provide a foundation for consistent future assumptions among air quality modelers and environmental policy analysts.

Gold, Michael D., Moulis, Charles E.

Factors Influencing the Composition and Quantity of Passenger Car Refueling Emissions — Part I

861558

10/1/1986

This paper describes the results of a study to examine the effects of various experimental variables on the quantity and composition of emissions associated with motor vehicle refueling. Problems related to accurate laboratory simulation of vehicle refueling are discussed. Preliminary results include emission rates for total hydrocarbons, benzene and 82 other hydrocarbon compounds for a single test vehicle under a variety of temperature and test conditions.

Braddock, James N., Gabele, Peter A., Lemmons, Thomas J.