| abstract |
Piston deposits resulting from neutralizing combustion acids present in the lubricating oil circulating within the lubrication system of an internal combustion engine are reduced or eliminated by first contacting the acids with a soluble weak base in the piston ring zone of the engine to form soluble neutral salts containing the weak base and the combustion acids. Thereafter, the neutral salts are contacted with a heterogeneous strong base immobilized within the lubrication system but outside the piston ring zone. The strong base displaces the weak base from the neutral salts, returning the weak base to the oil for recirculation to the piston ring zone for further use. The remaining strong base/combustion acid salts are immobilized as deposits with the strong base rather than on the piston. In a preferred embodiment, trioctadecyl amine is the weak base and zinc oxide is the strong base. In a particularly preferred embodiment, the weak base is incorporated on a substrate, preferably a cement binder. |