The effect of a gasoline additive, automobile make, and driving cycle on intake valve deposits (IVD) and combustion chamber deposits (CCD) in a ten-car fleet test

摘要

In a ten-car fleet test, the amount and chemical composition of intake valve deposits (IVD) and combustion chamber deposits (CCD) were determined. Five car makes, three driving cycles, and a gasoline with and without an IVD reducing additive were used. The amount of IVD and CCD were a strong function of car make, and the additive decreased IVD and increased CCD compared with nonadditized base gasoline. The chemical changes in the composition of the CCD show that the additive was the source of the increased CCD. For all vehicles tested, a modified AMA Driving Cycle and a BMW Driving Cycle produced similar amounts of IVD and CCD, with similar chemical compositions. In contrast, the high-speed cycle produced less CCD and gave CCD and IVD that had a different chemical composition than that of the other two driving cycles. No CCDI (combustion chamber deposit interference) and no driveability problems occurred during the normal course of accumulating mileage.