No fuel like a new fuel
12 Dec 2000
New fuels that combine diesel and dimethyl ether (DME), an additive that can be made from natural gas, coal, or biomass, show great promise for reduced pollutants and cleaner air. But how will the key components of a diesel engine – especially the fuel injector system – hold up?
To find out, the US Department of Energy have teamed up 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 litre, V-8 turbodiesel engine currently being modified to operate on the fuel blend. Navistar International and Caterpillar, 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 of Allentown, PA, using an advanced process developed with Energy Department support.
The US 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.
