<div class="htmlview paragraph">The use of diesel smoke suppressant additive (SSA) provides an effective method of suppressing black smoke formation in 25 different makes of engines tested both in Europe and the United States. A proposed mechanism is offered to explain the smoke suppressing action of the additive.</div> <div class="htmlview paragraph">The additive also reduces carbon deposits, provides antiwear protection for injectors and piston rings, and may offer a modest increase in fuel economy. Fleet tests covering more than 4,000,000 miles of operation have proved the value of SSA.</div> <div class="htmlview paragraph">Exhaust gas analyses are substantially unchanged by the use of SSA. Animal feeding and respiratory tests on the exhaust solids from engines using SSA-treated fuel show negligible toxicity.</div> <div class="htmlview paragraph">Additional benefits of SSA include better storage stability, improved antistatic properties, and antibacterial protection.</div>