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  Power transmission fluid with enhanced friction characteristicsUSPTO Application #: 20070293406Title: Power transmission fluid with enhanced friction characteristics Abstract: A power transmission fluid composition, a power transmission containing the fluid, a method of operating a power transmission with the fluid and method of improving friction durability for a power transmission fluid. The power transmission fluid includes (a) a base oil and (b) an additive composition having therein (i) at least one ashless dispersant; (ii) a metal detergent providing greater than about 100 ppm metal in the power transmission fluid composition; (iii) a friction modifying amount of an imidazoline; (iv) a succinimide friction modifier; and (v) a non-hydroxy tertiary amine friction modifier other than (iii). (end of abstract)
Agent: Luedeka, Neely & Graham, P.C. - Knoxville, TN, US Inventors: Timothy J. Henly, Samuel H. Tersigni USPTO Applicaton #: 20070293406 - Class: 508185 (USPTO) The Patent Description & Claims data below is from USPTO Patent Application 20070293406. Brief Patent Description - Full Patent Description - Patent Application Claims
FIELD [0001]The present disclosure relates to a power transmission fluid having improved and/or extended durability and enhanced friction characteristics. The present disclosure may comprise a fluid suitable for power transmitting fluids, such as an automatic transmission fluid (ATF) and/or a manual transmission fluid. Power transmitting fluids of the present disclosure may comprise friction modifiers, a borated dispersant, and a metal detergent. BACKGROUND AND SUMMARY [0002]Automotive power transmission fluids are called upon to provide specific frictional properties under very demanding conditions of temperature and pressure. Changes in a fluid's frictional properties as a function of relative sliding speed, temperature, or pressure as a result of these conditions may cause performance degradation immediately noticeable to the vehicle operator. Such effects may include unacceptably long or short gear shifts, vehicle shudder or vibration, noise, and/or harsh shifts ("gear change shock"). Thus, there is a need for transmission fluids that undergo minimal frictional changes under conditions of high temperatures and pressures. Such fluids would minimize equipment and performance problems while maximizing the interval between fluid changes. By enabling smooth engagement of torque converter and shifting clutches, these fluids would minimize shudder, vibration, and/or noise, and in some cases improve fuel economy, over a longer fluid lifetime. As newer transmissions are developed for improved fuel economy, there continues to be a need for fluids that are specifically formulated for such newer transmissions. [0003]In view of the ongoing needs for improved transmission fluids, exemplary embodiments of the disclosure provide a power transmission fluid composition, a method of operating a power transmission with the fluid and method of improving friction durability of a power transmission fluid. Power transmission fluids formulated according to the present disclosure provide improved friction durability and improved performance for smooth engagement of torque converter and shifting clutches and minimized shudder, vibration and/or noise, and/or improved fuel economy. [0004]In one exemplary embodiment, a power transmission fluid includes (a) a base oil and (b) an additive composition having therein (i) at least one ashless dispersant; (ii) a metal detergent providing greater than about 100 ppm metal in the power transmission fluid composition; (iii) a friction modifying amount of an imidazoline; (iv) a succinimide friction modifier; and (v) a non-hydroxy tertiary amine friction modifier other than (iii). [0005]Another exemplary embodiment provides a method of improving friction durability by adding to a base oil an additive composition. The additive composition may include (a) at least one ashless dispersant; (b) a metal detergent providing greater than about 100 ppm metal in a composition containing the base oil and additive composition; (c) a friction modifying amount of a hydroxyalkyl imidazoline; (d) a succinimide friction modifier; and (e) a non-hydroxy tertiary amine friction modifier other than (c). [0006]Power transmission fluids of the embodiments described herein are formulated to deliver improved friction durability, i.e., friction characteristics that change very little when the fluid is subjected to thermal and oxidative stresses. As used herein, "friction durability" means the ability of a fluid to resist physical and chemical changes that adversely affect the friction properties of the fluid during use. The disclosed power transmission fluids are suitable for use in transmissions where high stressing of the lubricant is routine, such as transmissions with a slipping torque converter, a lock-up torque converter, a starting clutch, and/or one or more shifting clutches. Such transmissions may include four-, five-, six-, seven, or eight-speed transmissions, or may include continuously variable transmissions (chain, belt, and disk type). The fluids may also be used in manual transmissions, including automated manual and dual-clutch transmissions. [0007]Both the foregoing general description and the following detailed description are exemplary and explanatory only and are intended to provide further explanation of the disclosed embodiments, as claimed. BRIEF DESCRIPTION OF THE DRAWINGS [0008]FIGS. 1-2 illustrate the difference in .mu.-v friction profiles before and after laboratory aging for different friction materials for a fluid containing an additive composition according to the disclosure and for conventional fluids. [0009]FIGS. 3-4 illustrate the low speed dynamic coefficients of friction in a Ford clutch friction durability test for a fluid containing the additive composition according to the disclosure and for conventional fluids. [0010]FIGS. 5-6 illustrate the midpoint dynamic coefficients of friction in a Ford clutch friction durability test for a fluid containing the additive composition according to the disclosure and for conventional fluids. [0011]FIGS. 7-8 illustrate the static breakaway coefficients of friction in a Ford clutch friction durability test for a fluid containing the additive composition according to the disclosure and for conventional fluids. [0012]FIGS. 9-10 illustrate ratios of low speed dynamic friction to midpoint dynamic friction (S1/D) in a Ford clutch friction durability test for a fluid containing the additive composition according to the disclosure and for conventional fluids. DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS [0013]As used herein, the term "hydrocarbyl substituent" or "hydrocarbyl group" is used in its ordinary sense, which is well-known to those skilled in the art. Specifically, it refers to a group having a carbon atom directly attached to the remainder of a molecule and having a predominantly hydrocarbon character. Examples of hydrocarbyl groups include: [0014](1) hydrocarbon substituents, that is, aliphatic (e.g., alkyl or alkenyl), alicyclic (e.g., cycloalkyl, cycloalkenyl) substituents, and aromatic-, aliphatic-, and alicyclic-substituted aromatic substituents, as well as cyclic substituents wherein the ring is completed through another portion of the molecule (e.g., two substituents together form an alicyclic radical); [0015](2) substituted hydrocarbon substituents, that is, substituents containing non-hydrocarbon groups which, in the context of the description herein, do not alter the predominantly hydrocarbon substituent (e.g., halo (especially chloro and fluoro), hydroxy, alkoxy, mercapto, alkylmercapto, nitro, nitroso, and sulfoxy); [0016](3) hetero-substituents, that is, substituents which, while having a predominantly hydrocarbon character, in the context of this description, contain other than carbon in a ring or chain otherwise composed of carbon atoms. Hetero-atoms include sulfur, oxygen, nitrogen, and encompass substituents such as pyridyl, furyl, thienyl and imidazolyl. In general, no more than two, preferably no more than one, non-hydrocarbon substituent will be present for every ten carbon atoms in the hydrocarbyl group; typically, there will be no non-hydrocarbon substituent in the hydrocarbyl group. [0017]Since power transmission fluids operate under increasingly severe conditions, the oils used to lubricate those transmissions should be formulated to endure higher temperatures and pressures. In order to minimize equipment problems and maximize the interval between transmission oil changes, the oil additive packages should be formulated so that important oil properties change as little as possible in the face of these stresses. In particular, the frictional properties of the oil, which depend in great measure on the additive package, must stay substantially constant. Substantially constant frictional properties ensure smooth engagement of torque converter and shifting clutches and minimized shudder, vibration and noise, and improved fuel economy. It has been found that the components herein disclosed, when blended into a base oil of suitable viscosity, impart to that oil greatly improved friction durability and other characteristics that are needed for newer more fuel efficient transmissions. [0018]In an exemplary embodiment, a power transmission fluid includes a base oil and an additive composition. The additive composition may contain at least one succinimide dispersant, a metal detergent providing greater about 100 ppm metal in the transmission fluid, a friction modifying amount of an imidazoline, a succinimide friction modifier, and a non-hydroxy tertiary amine friction modifier other than the imidazoline. Imidazoline [0019]An important component of the additive composition is the imidazoline, having the following general structure: wherein R.sup.1 is a straight or branched hydrocarbon chain containing from 10 to 25 carbon atoms and R.sup.2 is a C.sub.2 to C.sub.4 hydroxyalkyl group. [0020]Examples of suitable fatty acid hydrocarbyl imidazolines include but are not limited to heptadecenyl hydroxyalkyl imidazoline, octadecanoyl hydroxyalkyl imidazoline, linoleyl hydroxyalkyl imidazoline, linolenyl hydroxyalkyl imidazoline, docosanoyl hydroxyalkyl imidazoline, oleyl hydroxyalkyl imidazoline, eicosanoyl hydroxyalkyl imidazoline, tetracosanoyl hydroxyalkyl imidazoline, heptacosanoyl hydroxyalkyl imidazoline, and hexacosanoyl hydroxyalkyl imidazoline, wherein in each of the above, the alkyl group of the hydroxyalkyl is a C.sub.1 to C.sub.4 alkyl group. A particularly useful fatty acid hydrocarbyl imidazoline is 2-oleyl-1-hydroxyethyl imidazoline, due to its commercial availability and efficacy. The fatty acid hydrocarbyl imidazoline is included in a finished power transmission fluid in an amount ranging from about 0.005 to about 0.05 wt. % Ashless Dispersant Continue reading... Full patent description for Power transmission fluid with enhanced friction characteristics Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Power transmission fluid with enhanced friction characteristics patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. 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