Compositions – Electrolytes for electrical devices
Patent
1993-12-02
1995-07-25
Willis, Jr., Prince
Compositions
Electrolytes for electrical devices
252 546, C10M13110, C10M13112
Patent
active
054359279
DESCRIPTION:
BRIEF SUMMARY
This application is a 371 of PCT/GB93/00530 filed on 15 Mar. 1993.
The present invention relates to the reduction of the emission of undesirable materials such as unburnt hydrocarbons from internal combustion engines.
The emission of unburnt hydrocarbons from internal combustion engines is increasingly considered to be undesirable. Apart from any harmful effects of the hydrocarbons themselves they may react with other atmospheric pollutants and contribute to the formation of increased levels of atmospheric ozone, and photochemical smog.
One source of unburnt hydrocarbons in exhaust emissions involves the lubricating oil used in the engine. Most internal combustion engines make use of a piston reciprocating in a cylinder with a combustion chamber at one end. Movement of the piston within the cylinder is lubricated by a film of lubricating oil which is supplied to the cylinder on the side remote from the combustion chamber. Piston rings are provided to control oil thickness on the cylinder wall. However, fuel can be absorbed into the oil film during induction and compression and this can be desorbed after combustion and be emitted as unburnt hydrocarbons. Furthermore, evaporating lubricating oil can be responsible for undesirable emissions from internal combustion engines.
It would be desirable to find a way of reducing emissions in which lubricating oil is involved.
Accordingly the present invention provides a lubricating oil composition for use in an internal combustion engine comprising in the range of from 135 to 20,000, and Z is a functional group.
The base oil may be a conventional hydrocarbon base oil prepared by solvent extraction of fractions produced in the refining of crude oil. It may also be a synthetic hydrocarbon base oil produced by polymerisation. Alternatively, it may include a synthetic ester base oil. For the purposes of the present invention, a base oil contains a conventional multifunctional additive package.
The group R.sub.F is a perfluoropolyether moiety. In this specification "perfluorinated" is to be understood as corresponding to compounds in which the major part of any hydrogen atoms are replaced by fluorine atoms, e.g. more than 70% of the hydrogen atoms are replaced by fluorine atoms. It is believed that the best results will be obtained with compounds which are completely fluorinated.
The perfluoropolyether moiety preferably has an average molecular weight in the range of from 250 to 7000, especially from 400 to 2500 as explained below.
The perfluoropolyether moiety R.sub.F consists of a chain of perfluoroalkoxy groups terminated at one end with a perfluoroalkyl group e.g. a CX.sub.2 group, where each of X is separately F or CF.sub.3. Preferably CX.sub.2 is --CF(CF.sub.3) or CF.sub.2, more preferably CF.sub.2. The perfluoroalkoxy group may suitably be perfluoromethoxy --(CF.sub.2 O)--, perfluoroethoxy --(CF.sub.2 --CF.sub.2 --O)-- or perfluoropropoxy --(CF.sub.2 CF(CF.sub.3)O)--. The perfluoropolyether chain may comprise one of the aforementioned perfluoroalkoxy groups or a combination thereof. Where it is desired to have two or more different groups, suitably the chain comprises a mixture of either perfluoromethoxy groups. The ratio of the two alkoxy groups in the chain may suitably be in the range of from 20:1 to 1:20, preferably 5:1 to 1:5.
The functional group Z may suitably be a carboxylic acid or a carboxylate salt group. Alternatively, Z may be an ester, an amide, a hydroxy, a hydroxy methyl, an alkoxy, an alkoxy methyl or a polyol ether functionality.
Where Z is an ester functionality, Z may be derived from a poly(alkylene oxide) such as polyalkylene glycol, a polyalkylene alcohol such as polyisobutene alcohol, or a polyol such as polyvinyl alcohol. Z may also be derived from an alcohol such as octanol. The poly(alkylene oxide) may have a terminal hydroxy group.
Where Z is an amide functionality, Z may suitably be derived from the aforementioned poly(alkylene oxide), polyalkylene and polyol compounds having a terminal amine group. Z may also be derived from a primary o
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Beckwith Paul
Callaghan Ian C.
Masheder David
The British Petroleum Company p.l.c.
Toomer Cephia D.
Willis Jr. Prince
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