Effect of Biodiesel on Diesel Engine Nitrogen Oxide and Other Regulated Emissions

摘要

Diesel engines are widely used throughout the Department of Defense (DoD) for powering tactical and nontactical vehicles and vessels, off-road equipment, engine-generator sets, aircraft ground-support equipment and a variety of other applications. Although diesels are the most efficient of internal combustion engines and have favorable characteristics in the reduction of greenhouse gas emissions, concerns with the health effects from particulate matter (PM) and regulated hazardous air pollutants (HAP) emissions have intensified the call for cleaner burning diesels and led to recently proposed and enacted regulations increasing restrictions on diesel exhaust emissions. Because of these developments, many emissions control approaches are being pursued, including the development of cost-effective alternative fuels, such as biodiesel. Biodiesel is a nontoxic, biodegradable fuel made from organic fats and oils and serves as a replacement, substitute, and enhancer for petroleum diesel. Biodiesel may be blended with petroleum diesel in all existing diesel engines with little or no modification to the engines. It had previously been reported to reduce all regulated air pollutant emissions except emissions of nitrogen oxides (NOx). For this project, air emissions testing was performed on eight DoD-operated vehicles and two portable engines. Not all the same test cycles or fuels were used for each test engine. Multiple testing locations with different capabilities were used. The objective of this project is to establish emissions factors for DoD diesel powered engines of interest fueled with various blends and types of biodiesel, with and without the use of fuel additives that reduce NOx emissions from biodiesel. Most available biodiesel emissions data are for older heavy-duty engines tested on an engine dynamometer and fueled with a blend of virgin soybean derived biodiesel mixed with low sulfur Diesel Fuel No. 2.