Alternative Fuels - Ethanol Fuel

Ethanol is an alcohol-based fuel that is produced by fermenting and distilling crops that have been converted into simple sugars. Typically in the U.S., it is made from starch crops, primarily corn. It can also be made from sugar crops or from agricultural waste and "cellulosic biomass" such as trees and grasses. Because of its high oxygen content, ethanol is cleaner burning than gasoline. In the U.S., ethanol is sold in two gasoline blends: E85, which is composed of 85% ethanol and 15% gasoline (formulated for flexible-fuel vehicles), and E10, which is composed of 10% ethanol and 90% gasoline (formulated for conventional gasoline vehicles). The emission control technology suitable for engines operating on ethanol and gasoline blends would be similar to emission control technology used for gasoline-fueled vehicles.

Tags: Alternative Fuels, Alternative Fuel / Advanced Tech. Vehicles

Alternative Fuels - Biodiesel Fuel

Biodiesel is a renewable fuel that can be manufactured from new and used vegetable oils and animal fats. It is produced by reacting vegetable or animal fats with methanol or ethanol to produce a lower-viscosity fuel that is similar in physical characteristics to diesel, and which can be used neat or blended with petroleum diesel for use in a diesel engine. Biodiesel is commonly blended into petroleum-based fuel at low levels, i.e., 20 percent (B20) or less. Biodiesel can be used in its pure form (B100), but may require certain engine modifications to avoid maintenance and performance problems. Recently ASTM has developed specifications for B100 used as a fuel for mobile sources and specifications are under development for biodiesel blends like B20. Typical emissions benefits of B20 include a 10 percent decrease in CO, up to a 15 percent decrease in PM emissions, a 20 percent decrease in sulfate emissions, and a 10 percent decrease in HC emissions. In some tests, B20 has shown a slight increase in NOx emissions (up to three percent) on some types of existing heavy-duty engines. The emission control technology suitable for engines operating on biodiesel blends would be similar to emission control technology used for diesel-fueled vehicles.

Tags: Alternative Fuels, Alternative Fuel / Advanced Tech. Vehicles

Alternative Fuels - Hydrogen

Engine manufacturers have developed prototype internal combustion vehicles that can operate on hydrogen or dual fuel version that can use gasoline fuel as a second fuel source. These engines, called hydrogen internal combustion engines or HICE can operate on either compressed or liquid hydrogen using a slightly modified internal combustion engine. The resulting emissions from HICE are mostly water and NOx because they still involve a high temperature combustion process. The engine out emissions can be controlled to low levels requiring only a TWC emission control device to achieve California SULEV emission levels.

Tags: Alternative Fuels, Alternative Fuel / Advanced Tech. Vehicles