Abstract: This invention provides hydrocarbon oil compositions comprising a major amount of a hydrocarbon oil and, as active ingredients, minor amounts of a copolymer of at least one n-(C.sub.8 -C.sub.40 -alkyl) (meth)acrylate with maleic anhydride, and at least one additive selected from the group consisting of a homopolymer or copolymer derived from an unsaturated hydrocarbon monomer, an ester and a wax anti-settling additive; additive concentrates containing the active ingredients and use of the latter in improving the cold flow properties of hydrocarbon oils.

Abstract: A hydrocarbon oil composition comprising a paraffinic hydrocarbon oil and as an additive, at least one linear polymer of carbon monoxide with one or more .alpha.-olefins having at least 10 carbon atoms per molecule said polymer comprising of substantially alternating monomer units of carbon monoxide and olefins is disclosed. Optionally, the composition may also contain one or more C.sub.9+ or less olefin polymer comprising of substantially alternating monomer units of carbon monoxide and olefins. This composition has and exhibits improved pour point, cloud point, and cold filter plugging point properties. These polymer additives are novel compounds, and a process for their synthesis is also disclosed.

Abstract: Hydrocarbon oil compositions of improved low temperature properties comprise intimate mixtures of hydrocarbon oil and a linear alternating polymer of carbon monoxide and at least one straight-chain .alpha.-olefin of relatively high carbon number.

Abstract: The invention provides a diesel fuel additive for reducing fouling of injectors in diesel engines consisting of at least an effective concentration of a nitrogen-containing compound of general formulaCH.sub.3 (CH.sub.2).sub.n --A--NH.sub.2 (I)wherein n is 4 to 18 and A is --CH.sub.2 -- or --CO--, or a mixture thereof as an additive in a diesel fuel comprising a major proportion of a diesel oil and a method for using said additive.