Lubricity and Injector Pump Wear Issues with E diesel Fuel Blends

The search for alternative energy sources, particularly renewable sources, has led to increased activity in the area of ethanol blended diesel fuel, or E diesel. E diesel offers potential benefits in reducing greenhouse gases, reducing dependence on crude oil and reducing engine out emissions of particulate matter. However, there are some concerns about the use of E diesel in the existing vehicle fleet.

One of the chief concerns of the use of E diesel is the affect of the ethanol on the lubricating properties of the fuel and the potential for fuel system wear. Additive packages that are used to formulate E diesel fuels can improve fuel lubricity and prevent abnormal fuel system wear. This work studies the lubricity properties of several E diesel blends and the diesel fuels that are used to form them. In addition to a variety of bench scale lubricity tests, injector pump tests were performed as an indicator of long term durability in the field. While commonly used bench lubricity tests indicated that all E diesel blends provided sufficient lubricity, some of these fuels resulted in borderline or failing pump performance, and other E diesel blends showed very strong passing performance in the pump testing. Results indicate that it might not be possible to predict the fuel system durability performance of an E diesel blend based solely on an individual bench lubricity test.