Selection of an Engine Standard for Development of a CRC Intake Valve Deposit Test

The 1991 Ford 2.3L engine was selected as a test engine for purposes of developing a standard industry accepted intake valve deposit test. Candidate engine selection criteria and test protocol are discussed. Three 1991 domestic engine types were compared for intake valve deposit (IVD) characteristics using the SwRI/BMW on-road cycle. A composite blend of six, non-additized fuels was chosen for both base fuel and base fuel + additized tests. A test matrix was designed to assess both IVD accumulation characteristics and sensitivity to additive chemistry for each engine. Screening tests were performed using two 1985 BMW 318i sedans to find a suitable additive for additized tests and to use as a reference to the existing database.