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The Port Fuel Injector (PFI) Deposit Test is a performance-based test procedure developed by the Coordinating Research Council and adopted by state and federal regulatory agencies for fuel qualification in the United States. To date, Southwest Research Institute (SwRI) has performed over 375 PFI tests between 1991 and 1998 for various clients. This paper details the analyses of these tests. Of the 375 tests, 199 were performed as keep-clean tests and 176 were performed as clean-up tests. The following areas of interest are discussed in this paper: Keep-clean versus clean-up test procedures Linearity of deposit formation Injector position effects as related to fouling Dirtyup / cleanup phenomena Seasonal effects This paper draws the conclusion that it is easier to keep new injectors from forming deposits than it is to clean up previously formed deposits. It was found that injector deposit formation is generally non-linear.

An investigation of lubricant related fuel economy with two commercially available heavy-duty engine oils was performed using test methods that are currently available to the industry. The SAE J1321 on-highway fuel economy test procedure was utilized in a fleet of four heavy-duty trucks. Fuel economy benefit was defined relative to the CEC RL 191 reference oil that is the baseline candidate reference oil for the European light-duty gasoline engine fuel economy test procedure, CEC L-54-T-96 (Mercedes M111). Fuel economy improvement values were computed from the on-highway test results. Testing the same two lubricants in stationary engine dynamometer tests using the Mercedes M111 and the ASTM Sequence VIB test procedures also served as a crosscheck. Both engine dynamometer tests were found to rank the fuel economy performance of the commercial engine lubricants in the same order relative to RL 191 as did the SAE J1321 procedure.

Beginning June 1, 2006, 80% of the highway diesel fuel produced in the United States had to contain 15 ppm sulfur or less. To account for sulfur test method variability, the United States Environmental Protection Agency (US EPA) allowed a 2 ppm compliance margin, meaning that in an EPA enforcement action fuel measuring 17 ppm or less would still be deemed compliant since the true sulfur level could still be 15 ppm. Concern was voiced over the appropriateness of the 2 ppm compliance margin, citing recent American Society for Testing and Materials (ASTM) round-robin and crosscheck test program results that showed sulfur test lab-to-lab variability (reproducibility) on the order of 4 to 5 ppm depending on test method.

In response to industry demands for a method to qualify fuels for their intake valve deposit (IVD) forming tendencies, the Coordinating Research Council (CRC) has developed an engine dynamometer test procedure. In Phase I, the 2.3L Ford engine was chosen as the focus test engine in comparison testing with two other high volume U.S. manufactured engines.1* A two-mode dynamometer test was developed in Phases II-A & II-B and shown to discriminate among the test fuels at a 95% confidence level.2 In Phase III, both an interlaboratory study (ILS) of the two-mode dynamometer test and a vehicle fleet study were performed. The ILS was conducted to determine the repeatability and reproducibility of the test procedure and also to fulfill requirements for consideration of the test as an American Society for Testing and Materials (ASTM) standard.