Release Date: December 11, 2000

UNIVERSITY PARK, PA - Spurred by new tailpipe emission standards to take effect later this decade, the nation's automakers and fuel providers have joined with the U.S. government in developing lower-polluting fuels. One such fuel showing promise for reduced pollutants and cleaner air is a blend of diesel fuel and dimethyl ether (DME), an ultra-clean additive that can be made from natural gas, coal, or biomass.

But how will the key components of a diesel engine – especially the fuel injector system – hold up with this new fuel blend?

To find out, the U.S. Department of Energy's fossil energy program will expand an ongoing project with Pennsylvania State University, University Park, PA, to test DME-diesel blends in a campus shuttle bus.

Researchers hope to develop a database of information on how key properties of these fuel blends – such as viscosity, the way the liquid fuel compresses, and its effectiveness in reducing friction (lubricity) – affect the performance, durability, and spray patterns of the fuel injectors.

Firing DME-diesel blends creates challenges for the engine manufacturer. For example, the DME-blended fuel must be injected under high enough pressures (around 90 pounds per square inch) to keep the dimethyl-ether in liquid form. Researchers are especially interested in how the higher pressures affect the wear rate of the injectors and whether additives will be required to improve the fuel's lubricating properties.

The test vehicle in the project will be a campus shuttle bus powered by a Navistar 7.3 liter, V-8 turbodiesel engine currently being modified to operate on the fuel blend. Navistar International and Caterpillar Inc., the manufacturers of the electronic fuel injectors for the engine, will assist the Penn State team in designing and constructing the injector durability test equipment.

The dimethyl ether will be produced by Air Products and Chemicals Inc., Allentown, PA, using an advanced process developed with Energy Department support.

The Energy Department will provide $166,000 for the 2-year project through its National Energy Technology Laboratory in Pittsburgh, PA, and Morgantown, WV. Penn State and its team members will contribute $31,600.