Development of an Intake Valve Deposit Test with a GM LE9 2.4L Engine

The U.S. Environmental Protection Agency (EPA) certifies gasoline deposit control additives for intake valve deposit (IVD) control utilizing ASTM D5500, a vehicle test using a1985 BMW 318i. Concerns with the age of the test fleet, its relevance in the market today, and the availability of replacement parts led the American Chemistry Council’s (ACC) Fuel Additive Task Group (FATG) to begin a program to develop a replacement. General Motors suggested using a 2.4L LE9 test engine mounted on a dynamometer and committed to support the engine until 2030. Southwest Research Institute (SwRI®) was contracted to run the development program in four Phases. In Phase I, the engine test stand was configured, and a test fuel selected. In Phase II, a series of tests were run to identify a cycle that would build an acceptable level of deposits on un-additized fuel. In Phase III, the resultant test cycle was examined for repeatability. In Phases IVa and IVb, two discrimination matrices evaluated the response of additives on IVD levels. The results of Phase IVa indicated the EPA 65^thpercentilefuel and test procedure combination did not compare with historical BMW results or replicate additive discrimination. The results of Phase IVb, using a TOP TIER™ certification fuel, showed a representative additive response in the LE9. ACC FATG considers the initial test development complete, but continued evaluation of the fuel, hardware, and test cycle will be required. With continued development in a Coordinating Research Council program, ACC FATG anticipates that the 9 2.4L IVD test can be standardized as an ASTM test method, and used as an alternate or replacement for the ASTM D5500 in both EPA and California Air Resources Board Reformulated Gasoline regulations. This would also position the 2.4L IVD test to become a replacement for the ASTM D6201 IVD test.