Lubricity additives for fuels

Abstract

Fuel additive compositions that include synergistic mixtures of one or more neutral lubricity additives and one or more monoacidic lubricity additives to provide wear and/or friction reduction in fuels.

What is claimed is: 
     
         1 . A gasoline additive providing lubricity, the gasoline additive comprising a lubricity additive mixture of (i) at least one neutral lubricity additive prepared by reacting a hydrocarbyl-substituted polycarboxylic acid compound with ammonia and (ii) at least one linear monocarboxylic acid or salt thereof, the linear monocarboxylic acid or salt thereof being saturated, unsaturated, or including mixtures thereof. 
     
     
         2 . The gasoline additive of  claim 1 , wherein a weight ratio of (i) the at least one neutral lubricity additive divided by (ii) the at least one linear monocarboxylic acid or salt thereof is about 0.2 to about 30. 
     
     
         3 . The gasoline additive of  claim 2 , wherein the weight ratio is about 2 to about 30. 
     
     
         4 . The gasoline additive of  claim 1 , wherein the hydrocarbyl substituent of the polycarboxylic acid compound is a linear or branched C6 to C36 group. 
     
     
         5 . The gasoline additive of  claim 1 , wherein the hydrocarbyl-substituted polycarboxylic acid is a hydrocarbyl-substituted succinic acid or an anhydride thereof. 
     
     
         6 . The gasoline additive of  claim 1 , wherein the at least one linear monocarboxylic acid or salt thereof includes a linear carbon chain having 6 to 24 carbon atoms. 
     
     
         7 . The gasoline additive of  claim 6 , wherein the at least one linear monocarboxylic acid or salt thereof is selected from the group consisting of lauric acid, tridecanoic acid, myristic acid, pentadecanoic acid, palmitic acid, margaric acid, stearic acid, arachidic acid, behenic acid, oleic acid, erucic acid, palmitoleic acid, myristoleic acid, linoleic acid, linolenic acid, elaeosteric acid, arachidonic acid, coconut oil fatty acid, peanut oil fatty acid, linseed oil fatty acid, palm oil fatty acid, rapeseed oil fatty acid, soybean oil fatty acid, sunflower oil fatty acid, tall oil fatty acid, mixtures thereof, and salts thereof. 
     
     
         8 . The gasoline additive of  claim 1 , further comprising a detergent selected from the group consisting of (i) one or more Mannich reaction products formed by condensing a long chain aliphatic hydrocarbon-substituted phenol or cresol with an aldehyde, and an amine, (ii) long chain aliphatic hydrocarbons having an amine or a polyamine attached thereto, (iii) fuel-soluble nitrogen containing salts, amides, imides, succinimides, imidazolines, esters, and long chain aliphatic hydrocarbon-substituted dicarboxylic acids or their anhydrides or mixtures thereof, (iv) polyetheramines; (v) quaternary amines and salts thereof and (vi) combinations thereof. 
     
     
         9 . A fuel comprising a major amount of a spark-ignitable fuel and a minor amount of a lubricity additive mixture, the lubricity additive mixture including (i) at least one neutral lubricity additive prepared by reacting a hydrocarbyl-substituted polycarboxylic acid with ammonia and (ii) at least one linear monocarboxylic acid or salt thereof, the linear monocarboxylic acid or salt thereof being saturated, unsaturated, or including mixtures thereof. 
     
     
         10 . The fuel of  claim 9 , wherein a weight ratio of (i) the at least one neutral lubricity additive divided by (ii) the at least one linear monocarboxylic acid or salt thereof is about 0.2 to about 30. 
     
     
         11 . The fuel of  claim 10 , wherein the weight ratio is about 2 to about 30. 
     
     
         12 . The fuel of  claim 9 , wherein a treat rate of the at least one lubricity additive mixture in the fuel is at least about 2 PTB. 
     
     
         13 . The fuel of  claim 9 , wherein the hydrocarbyl substituent of polycarboxylic acid is a linear or branched C6 to C36 group. 
     
     
         14 . The fuel of  claim 9 , wherein the hydrocarbyl-substituted polycarboxylic acid is a hydrocarbyl-substituted succinic acid or anhydride thereof. 
     
     
         15 . The fuel of  claim 9 , wherein the at least one linear monocarboxylic acid or salt thereof includes a linear carbon chain having 6 to 24 carbon atoms. 
     
     
         16 . The fuel of  claim 9 , wherein the at least one linear monocarboxylic acid or salt thereof is selected from the group consisting of lauric acid, tridecanoic acid, myristic acid, pentadecanoic acid, palmitic acid, margaric acid, stearic acid, arachidic acid, behenic acid, oleic acid, erucic acid, palmitoleic acid, myristoleic acid, linoleic acid, linolenic acid, elaeosteric acid, arachidonic acid, coconut oil fatty acid, peanut oil fatty acid, linseed oil fatty acid, palm oil fatty acid, rapeseed oil fatty acid, soybean oil fatty acid, sunflower oil fatty acid, tall oil fatty acid, mixtures thereof, and salts thereof. 
     
     
         17 . The fuel of  claim 9 , further comprising a detergent selected from the group consisting of (i) one or more Mannich reaction products formed by condensing a long chain aliphatic hydrocarbon-substituted phenol or cresol with an aldehyde, and an amine, (ii) long chain aliphatic hydrocarbons having an amine or a polyamine attached thereto, (iii) fuel-soluble nitrogen containing salts, amides, imides, succinimides, imidazolines, esters, and long chain aliphatic hydrocarbon-substituted dicarboxylic acids or their anhydrides or mixtures thereof, (iv) polyetheramines; (v) quaternary amines and salts thereof; and (vi) combinations thereof. 
     
     
         18 . A method of reducing wear in a gasoline engine comprising operating the gasoline engine with a fuel including a major amount of gasoline and a minor amount of a lubricity additive mixture, the lubricity additive mixture including (i) at least one hydrocarbyl ammonial-succinimide or succinamide neutral lubricity additive and (ii) at least one linear monoacidic lubricity additive or salt thereof. 
     
     
         19 . The method of  claim 18 , wherein a weight ratio of (i) the at least one hydrocarbyl ammonial-succinimide or succinamide neutral lubricity additive divided by (ii) the at least one linear monoacidic lubricity additive or salt thereof is about 0.2 to about 30. 
     
     
         20 . The method of  claim 19 , wherein a treat rate of the lubricity additive mixture in the fuel is at least about 2 PTB. 
     
     
         21 - 25 . (canceled)