| abstract |
A lubricating oil composition is described which is useful in spark-ignited engines which may be fueled with gasoline, alcohol, or mixtures of both. More particularly, lubricating oil compositions for spark-ignited engines are described which comprise (A) an oil of lubricating viscosity; (B) at least one detergent selected from the group consisting of a basic magnesium salt of an organic acid or a mixture of at least one basic magnesium salt of an organic acid and another alkaline earth metal salt of an organic acid wherein the metal in the mixture is predominantly magnesium; and (C) at least one metal salt of (C-1) a substituted succinic acid acylated polyamine; or (C-2) a hydrocarbon-substituted aromatic carboxylic acid containing at least one hydroxyl group attached to an aromatic ring, provided that the metal of said metal salt (C) is not calcium or magnesium. Lubricants primarily useful for lubricating alcohol-fueled, spark-ignited engines also are described which comprise (A) a lubricating oil, (B) a detergent as described above, and (D) at least one carboxylic acid derivative composition useful as a dispersant. The oil compositions of the invention also may contain, and generally do contain other desirable additives such as (E) mixtures of metal salts of dihydrocarbyl phosphorodithioic acids; (F) sulfurized olefins; etc. In one embodiment, the oil compositions of the present invention contain the above additives and other additives described in the specification in amounts sufficient to enable the oil to meet all the performance requirements of the API Service Classification identified as "SG". |