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
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.