US Patent 7124729 Additive-containing, dissolvable coating on engine part that contacts oil

An engine part that contacts oil during engine operation has a coating layer that provides one or more oil additives into the oil during a desired period of engine use. The coating layer includes one or more oil additives that are incorporated into the oil over the period of engine use as well as a coating matrix that releases the additive(s), e.g. by dissolution or diffusion of the additive(s), into the oil over the desired period of engine use. The additives replenish the oil to maintain or improve oil performance over the period of engine use.