Spiro compound as detergent additive in lubricants for marine engines

The use as claimed in the preceding claim, said spiro compound being of formula (I) in which the R substituents represent, independently of one another, a linear or branched aliphatic chain, especially a preferably linear C1 to C50, especially C3 to C30, in particular C5 to C25 and more particularly C5 to C20, more preferentially C16, alkyl chain.

The use as claimed in any one of the preceding claims, said spiro compound being of formula (I) in which M is a boron atom.

The use as claimed in any one of the preceding claims, said spiro compound(s) being employed in a content of between 0.1% and 20% by weight, with respect to the total weight of said lubricating composition, preferably of between 0.2% and 15% by weight, more preferably between 0.5% and 10% by weight and more particularly from 0.5% to 5% by weight.

The use as claimed in any one of the preceding claims, said lubricating composition comprising at least one metallic detergent additive, distinct from the spiro compound of formula (I), in particular at least one overbased metallic detergent additive and/or one neutral metallic detergent additive, in particular based on calcium.

The use as claimed in any one of the preceding claims, said composition comprising one or more base oils in a content of at least 50% by weight, with respect to its total weight, in particular of at least 60% by weight, more particularly ranging from 65% to 99% by weight and preferably from 70% to 98% by weight.

The use as claimed in any one of the preceding claims, said composition being of SAE-20, SAE-30, SAE-40, SAE-50 or SAE-60 viscometric grade according to the SAEJ300 classification.

The use as claimed in any one of the preceding claims, said lubricating composition being a lubricant for a two-stroke or four-stroke engine, in particular a lubricant intended for the lubrication of the piston-ring-liner assembly of said marine engine.