Influence of Ethanol-Blended Fuels on the Emissions from Three Pre-1985 Light-Duty Passenger Vehicles

Abstract

Tailpipe and evaporative emissions from three pre-1985 passenger motor vehicles operating on an ethanol oxygenated and on a nonoxygenated (base) fuel were characterized. Emission data were collected for vehicles operating over the Federal Test Procedure at 90 °F, 75 °F, and 40 °F to simulate ambient driving conditions. The two fuels tested were a commercial summer-grade regular gasoline (the nonoxygenated base fuel) and an oxygenated fuel containing 8.8% ethanol, more paraffins and olefins, and less aromatics than the base fuel. The Reid vapor pressure (RVP) was adjusted to correspond to that of the base fuel. The emissions measured were total hydrocarbons (THCs), speciated hydrocarbons, spedated aldehydes, carbon monoxide (CO), and oxides of nitrogen (NO X ).This study showed a general reduction in tailpipe emissions of THC, CO, benzene, and 1,3-butadiene when tested with the ethanol fuel. The ethanol fuel significantly reduced these emissions from the high emitting vehicle, MU098, at 90 °F, 75 °F, and 40 °F test temperatures. Additionally, the ethanol fuel reduced CO emissions from vehicle BU950, with and without catalyst, and from vehicle CI415 at 40 °F. Both formaldehyde and acetaldehyde emissions generally increased when tested with the oxygenated fuel. The acetaldehyde emissions were about double with this fuel. The limited data indicate that most emissions, including toxics, occur during the first 124 seconds of vehicle start-up.Diurnal evaporative emissions were less from the oxygenated fuel, while hot-soak evaporative emissions were greater from the oxygenated fuel (for all vehicles except MU098). Evaporative emissions were generally greatest at the 90 °F test temperature. IMPLICATIONSThis paper is the second of a series examining the effects of oxygenated fuels (fuels containing selected alcohols and ethers) on tailpipe and evaporative emissions from three pre-1985 vehicles. The regulated and unregulated emission values obtained from these tests will be integrated into EPA's Mobile 5 air modeling program. The Mobile 5 program is used to estimate the seasonal influence of emissions from motor vehicles using oxygenated fuels on the air quality at specific geographical locations. INTRODUCTIONMotor vehicles make a significant contribution to the atmospheric pollution inventory. Vehicles emit large quantities of hydrocarbons (HCs), CO, CO 2 , and oxides of nitrogen (NO X ). HCs and NO X are the principal components in the atmospheric photochemical processes that form ozone and other oxidants. Vehicles also emit formaldehyde, acetaldehyde, benzene, and 1,3-butadiene, which are of major health concern (classified as probable human carcinogens).

Reduced Kinetic Mechanism for Methanol Combustion in Spark-Ignition Engines

“…Pollutant formation is an important concern when developing engines for biofuels. NOx, UHC, particulate matter (PM), soot and CO are all important emissions from biofuels, similar to traditional fuels 8 , but there are also elevated levels of oxygenated intermediates like CH2O in biofuel exhaust 3,9,10 . CH2O is carcinogenic and produce ground-level ozone 3,[11][12][13] .…”

Performance and Emission Characteristics of Spark Ignition Engine Fuelled with Ethanol and Methanol Gasoline Blended Fuels

“…When ethanol and methanol containing oxygen is blended with gasoline, the combustion of the engine becomes better and therefore CO emission is reduced (Stump et al, 1996;Yasar, 2010). As seen in Fig.…”

Effect of different levels of ethanol addition on performance, emission, and combustion characteristics of a gasoline engine

“…6 However, in cases where engine and ignition advance are not modified, it is reported by Dai et al 19 and Li et al 13 who compared ethanol and gasoline and by Costa et al 12 who compared ethanol and ethanol-gasoline mixture in their studies that ethanol causes lower THC and CO, higher NO x emission. In study of Stump et al 20 who performed tests on different vehicles at cruise cycles, it is found that HC and CO emissions decrease with ethanol addition while NO x emissions mostly increase. NO x , THC, and CO emission results in study are parallel with results of Schifter et al 8 Table 5 summarizes the effects of ethanol content of fuel on performance and emission characteristics, which are obtained from simulation results.…”