Program to Evaluate a Vehicle Test Method for Port Fuel Injector Deposit-Forming Tendencies of Unleaded Base Gasolines

摘要

Car owners complaining of operability problems with port fuel injector (PFI) systems late in 1984. Deposits within the tips of the pintle-type injectors of certain engines restricted fuel flow and caused misfiring. The automakers and gasoline marketers sought a test method that would enable determination of causative factors and consequent solutions. The Coordinating Research Council (CRC) Automotive Fuel Injector Deposit Group, organized in March 1986, developed a program which led to selection of a vehicle procedure for a round robin evaluation. The cycle involved 15 minutes operation at 88 kph (55 mph) followed by a 45 minute hot soak shutdown with total test durations of 4800 to 9600 km (3000 to 6000 miles). Twelve laboratories ran various combinations of three different base unleaded gasolines in five types of port fuel injected engines. From this set, data from 38 runs were analyzed, representing eleven laboratories and four engine types. Even though all test conditions were not tightly controlled, results showed statistically significant differences (at the 95% confidence level) in deposit-forming tendencies of the fuels as well as the vehicles. The test approach is useful for relative performance evaluations but more development effort is needed before it could serve as a quantitative measure. (KT)