Development of a laboratory test for multiport injector deposits: approaches 1 and 2. Final report

This report evaluates a novel approach for measuring MPFI(Multiport Fuel Injectors) injector deposit-forming tendencies of fuel. By slowly coating a cylindrical metal surface with a thin film of gasoline and applying sufficient amounts of heat in alternate cycles of coating and soaking, two critical requirements of deposit formation were used. The deposit generated from a known injector-fouling fuel (fuel A) were measured gravimetrically and compared to a relatively clean fuel (fuel C). Significantly greater concentrations of deposits were measured from fuel A when compared to fuel C. Fuel A was treated with 2 different types of additives-polymeric and amine-from 4 different manufacturers at high, clean-up levels and low, keep-clean concentrations and evaluated by the Bomb Method. Very few deposits were measured by any of the additive-treated fuels at high or low treatment levels. Greatly reduced levels of each additive in fuel A were tested for additive response by measuring deposit formation of as a function of additive concentration. Several additives appeared to begin losing their efficacy at lower concentrations in fuel A. With an improved design of the delivery system and optimization of experimental parameters, the Bomb Method promises to be a viable bench test method for measuring the deposit-formingmore » tendencies of fuel.« less