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Saint Helena, CO, United States

Hu J.,North Carolina State University | Frey H.C.,North Carolina State University | Sandhu G.S.,North Carolina State University | Graver B.M.,North Carolina State University | And 4 more authors.
Environmental Science and Technology | Year: 2014

As input to a winter use plan, activity, fuel use, and tailpipe exhaust emissions of over snow vehicles (OSV), including five snow coaches and one snowmobile, were measured on a designated route in Yellowstone National Park (YNP). Engine load was quantified in terms of vehicle specific power (VSP), which is a function of speed, acceleration, and road grade. Compared to highway vehicles, VSP for OSVs is more sensitive to rolling resistance and less sensitive to aerodynamic drag. Fuel use rates increased linearly (R2 > 0.96) with VSP. For gasoline-fueled OSVs, fuel-based emission rates of carbon monoxide (CO) and nitrogen oxides (NOx) typically increased with increasing fuel use rate, with some cases of very high CO emissions. For the diesel OSVs, which had selective catalytic reduction and diesel particulate filters, fuel-based NOx and particulate matter (PM) emission rates were not sensitive to fuel flow rate, and the emission controls were effective. Inter vehicle variability in cycle average fuel use and emissions rates for CO and NOx was substantial. However, there was relatively little inter-cycle variation in cycle average fuel use and emission rates when comparing driving cycles. Recommendations are made regarding how real-world OSV activity, fuel use, and emissions data can be improved. © 2014 American Chemical Society.

Ratcliff M.A.,U.S. Department of Energy | Luecke J.,U.S. Department of Energy | Williams A.,U.S. Department of Energy | Christensen E.,U.S. Department of Energy | And 3 more authors.
Environmental Science and Technology | Year: 2013

Certification gasoline was splash blended with alcohols to produce four blends: ethanol (16 vol%), n-butanol (17 vol%), i-butanol (21 vol%), and an i-butanol (12 vol%)/ethanol (7 vol%) mixture; these fuels were tested in a 2009 Honda Odyssey (a Tier 2 Bin 5 vehicle) over triplicate LA92 cycles. Emissions of oxides of nitrogen, carbon monoxide, non-methane organic gases (NMOG), unburned alcohols, carbonyls, and C1-C8 hydrocarbons (particularly 1,3-butadiene and benzene) were determined. Large, statistically significant fuel effects on regulated emissions were a 29% reduction in CO from E16 and a 60% increase in formaldehyde emissions from i-butanol, compared to certification gasoline. Ethanol produced the highest unburned alcohol emissions of 1.38 mg/mile ethanol, while butanols produced much lower unburned alcohol emissions (0.17 mg/mile n-butanol, and 0.30 mg/mile i-butanol); these reductions were offset by higher emissions of carbonyls. Formaldehyde, acetaldehyde, and butyraldehyde were the most significant carbonyls from the n-butanol blend, while formaldehyde, acetone, and 2-methylpropanal were the most significant from the i-butanol blend. The 12% i-butanol/7% ethanol blend was designed to produce no increase in gasoline vapor pressure. This fuel's exhaust emissions contained the lowest total oxygenates among the alcohol blends and the lowest NMOG of all fuels tested. © 2013 American Chemical Society.

Yanowitz J.,Ecoengineering Inc. | Knoll K.,National Renewable Energy Laboratory | Knoll K.,SGS Environmental Testing Corporation | Luecke J.,National Renewable Energy Laboratory | McCormick R.L.,National Renewable Energy Laboratory
Environmental Science and Technology | Year: 2013

Nine flex-fuel vehicles meeting Tier 1, light duty vehicle-low emission vehicle (LDV-LEV), light duty truck 2-LEV (LDT2-LEV), and Tier 2 emission standards were tested over hot-start and cold-start three-phase LA92 cycles for nonmethane organic gases, ethanol, acetaldehyde, formaldehyde, acetone, nitrous oxide, nitrogen oxides (NOx), carbon monoxide (CO), and carbon dioxide (CO2), as well as fuel economy. Emissions were measured immediately after refueling with E40. The vehicles had previously been adapted to either E10 or E76. An overall comparison of emissions and fuel economy behavior of vehicles running on E40 showed results generally consistent with adaptation to the blend after the length of the three-phase hot-start LA92 test procedure (1735 s, 11 miles). However, the single LDT2-LEV vehicle, a Dodge Caravan, continued to exhibit statistically significant differences in emissions for most pollutants when tested on E40 depending on whether the vehicle had been previously adapted to E10 or E76. The results were consistent with an overestimate of the amount of ethanol in the fuel when E40 was added immediately after the use of E76. Increasing ethanol concentration in fuel led to reductions in fuel economy, NOx, CO, CO2, and acetone emissions as well as increases in emissions of ethanol, acetaldehyde, and formaldehyde. © 2013 American Chemical Society.

Dolch J.,Ford Motor Company | Reek A.,SGS Environmental Testing Corporation | Glinsky G.,SGS Environmental Testing Corporation | Dicicco D.,Ford Motor Company | And 2 more authors.
SAE Technical Papers | Year: 2013

In order to meet more stringent evaporative emissions requirements, multiple advancements in vehicle fuel system and carbon canister technologies have been made. Regardless of technological advancements, the vapor pressure of the fuel remains a vital property in controlling evaporative emissions. A series of tests were performed to explore the effects of vapor pressure on multiday diurnal evaporative emissions for 9 and 10 psi Reid Vapor Pressure (RVP) 10% ethanol (E10) gasoline-blend fuels, followed by tests with 7 psi RVP E10 gasoline on a subset of the same vehicles. A test procedure was developed to monitor evaporative emissions, canister loading profiles and breakthrough emissions for each of the fuels. A total of five vehicles were tested on all 3 fuels, blended to represent 7, 9, and 10 psi at sea level. Tests were run over 14 days using the United States (U.S.) Federal Diurnal Cycle (72°F to 96°F) in a Sealed Housing for Evaporative Determination (SHED) at a test facility in Colorado. Two of the five vehicles had evaporative emissions systems that met the California Air Resources Board (CARB) requirements for a Partial Zero Emission Vehicle (PZEV), while the other three vehicles were certified to U.S. Tier 2 evaporative emissions standards. The data collected throughout the testing provide a correlation between the hydrocarbon slip from the vehicle canister and the fuel vapor pressure. The data indicate that achieving lower evaporative emissions can be accomplished through the use of decreased vapor pressure fuels. Copyright © 2013 SAE International.

Vertin K.,SGS Environmental Testing Corporation | Reek A.,SGS Environmental Testing Corporation
SAE International Journal of Fuels and Lubricants | Year: 2014

The U.S. EPA has proposed a Tier 3 rule to lower average NMOG+NOx emissions from new light duty vehicles by approximately 80% from 2017 to 2025. Early in this time period, gasoline-fueled vehicles are expected to use technologies similar to California SULEV-II/PZEV certified models currently in limited production. These late model vehicles feature engine control systems that promote rapid catalyst light-off and are designed for ultra-high catalyst conversion efficiency. To enable the use of advanced catalyst coatings and materials, the EPA is also proposing to limit the sulfur content of gasoline to an annual average of 10 ppm while optionally maintaining the current maximum cap of 80 ppm. Fuel sulfur is known to poison precious metal-based catalysts, and the impact on emissions is well understood for older technology vehicles. However, there is a lack of test data on the sensitivity and reversibility of late model vehicle emissions to sulfur. This study evaluated six late model vehicles to determine if the exhaust emissions effects caused by exposure to 80 ppm high sulfur fuel were reversible, after the vehicles were refueled with 10 ppm sulfur fuel. Catalysts and sensors were aged to full useful life in the laboratory and then installed on the vehicles for testing. A statistical analysis concluded that there was no difference in the mean emissions of NMOG, NOx, CO, Soot and PN measured before and after the high sulfur fuel exposure. The emissions effects caused by high sulfur fuel exposure were reversible for all vehicles with 95% confidence. Copyright © 2014 SAE International.

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