I stumbled on the patent for it, which is very interesting and informative. Esters are what performs the cleaning, and in some example formulations, alkylated naphthalene was also added. Alkylated naphthalene is between typical esters and Groups II-IV in terms of polarity. They aimed for an aniline point of roughly 60C, which is very low for a motor oil. Lower aniline point indicates higher polarity.
This oil was mostly developed for cleaning carbon from pistons/rings in heavy duty diesel engines but cleaning of gasoline engines was also mentioned. The patent states what some of here have said: it is common for a decent oil to keep an engine clean if OCI is appropriate, but most oils are not good at cleaning engines that are not clean. If you can stomach the sticker shock of this oil (~$72/gallon), go for it and let us know how all it cleans. Below are excerpts from the patent, and I’m not putting it a quote because that narrows the width and the text is long.
http://www.freepatentsonline.com/y2017/0029734.html
Here are 4 example formulation with percentages for each ingredient, and the viscosities.
“There are three types of deposits which can form on pistons and rings: sludge, varnish and hard carbon. Hard carbon is the most difficult to remove. Over a period of time, carbon deposits can form in certain internal combustion engines, particularly on the piston lands, and in the grooves between the rings and the piston. These carbon deposits frequently manifest themselves by increased oil consumption. Carbon deposit can cause the piston rings to stick, which prevents them from forming a proper seal which allows oil into the combustion chamber and allows the combustion products into the oil. Carbon deposits between the rings and grooves and on the lands can cause irreversible damage to the engine.
Typical lubricants used in internal combustion engines are designed to retard deposit formation but not to remove the carbon buildup that has accumulated over time. This is especially relevant in modern internal combustion engines where additional performance demands have increased piston temperatures.
Further, lubricants for internal combustion engines must be compatible with elastomers such as seals in the engine, have acceptable corrosion resistance, be adequate in cleaning the engine and not exhibit excessive oil consumption. In order to be used in diesel engines the formulated lubricant must have enough detergency and dispersancy to pass the multiple engine tests required for the particular manufacturer's specification and/or the requirements of the specification of the American Petroleum Institute “C” or “F” category for diesel engine oils or likewise the ACEA (European Automobile Manufacturers Association) diesel categories. Yet the ash containing components necessary to pass these demanding specifications typically exacerbate deposits. Thus although it is possible to produce an engine oil with a low tendency to form deposits using conventional high aniline point base oils (e.g. some oils used in natural gas engines) it will typically not pass specifications for use with diesel engines. Furthermore, such an oil outside the range of solvency proscribed herein does not have the effect of cleaning and freeing piston rings thereby reducing oil consumption or preventing loss of oil consumption.
SUMMARY OF THE INVENTION
The present invention is premised on the realization that a lubricant formulation can act to prevent and/or remove carbon buildup in an internal combustion engine.
In particular, a lubricant formulation formed from a blend of base oils with a defined solvency of the base oil, a volatility below a defined threshold (15% as measured by NOACK), a minimum oxidative stability (above 40 minutes as measured by PDSC) and a base oil viscosity of from about 2 to about 10 cSt can effectively prevent the carbon buildup and remove carbon buildup. The solvency can be measured by various methods, such as, for example, aniline point. Lubricant formulations with a base oil blend having an aniline point of 20-115 and preferably 60, should adequately remove carbon buildup in engines and still exhibit elastomer compatibility.
The base oil formulation is formed by blending Group III and/or Group IV lubricants with higher solvency base oil from Group V in relative amounts to establish the effective solvency, volatility, oxidative stability and base oil viscosity, while remaining compatible with elastomers, providing acceptable corrosion prevention and cleaning of the engine without excessive oil consumption.”
This oil was mostly developed for cleaning carbon from pistons/rings in heavy duty diesel engines but cleaning of gasoline engines was also mentioned. The patent states what some of here have said: it is common for a decent oil to keep an engine clean if OCI is appropriate, but most oils are not good at cleaning engines that are not clean. If you can stomach the sticker shock of this oil (~$72/gallon), go for it and let us know how all it cleans. Below are excerpts from the patent, and I’m not putting it a quote because that narrows the width and the text is long.
http://www.freepatentsonline.com/y2017/0029734.html
Here are 4 example formulation with percentages for each ingredient, and the viscosities.
“There are three types of deposits which can form on pistons and rings: sludge, varnish and hard carbon. Hard carbon is the most difficult to remove. Over a period of time, carbon deposits can form in certain internal combustion engines, particularly on the piston lands, and in the grooves between the rings and the piston. These carbon deposits frequently manifest themselves by increased oil consumption. Carbon deposit can cause the piston rings to stick, which prevents them from forming a proper seal which allows oil into the combustion chamber and allows the combustion products into the oil. Carbon deposits between the rings and grooves and on the lands can cause irreversible damage to the engine.
Typical lubricants used in internal combustion engines are designed to retard deposit formation but not to remove the carbon buildup that has accumulated over time. This is especially relevant in modern internal combustion engines where additional performance demands have increased piston temperatures.
Further, lubricants for internal combustion engines must be compatible with elastomers such as seals in the engine, have acceptable corrosion resistance, be adequate in cleaning the engine and not exhibit excessive oil consumption. In order to be used in diesel engines the formulated lubricant must have enough detergency and dispersancy to pass the multiple engine tests required for the particular manufacturer's specification and/or the requirements of the specification of the American Petroleum Institute “C” or “F” category for diesel engine oils or likewise the ACEA (European Automobile Manufacturers Association) diesel categories. Yet the ash containing components necessary to pass these demanding specifications typically exacerbate deposits. Thus although it is possible to produce an engine oil with a low tendency to form deposits using conventional high aniline point base oils (e.g. some oils used in natural gas engines) it will typically not pass specifications for use with diesel engines. Furthermore, such an oil outside the range of solvency proscribed herein does not have the effect of cleaning and freeing piston rings thereby reducing oil consumption or preventing loss of oil consumption.
SUMMARY OF THE INVENTION
The present invention is premised on the realization that a lubricant formulation can act to prevent and/or remove carbon buildup in an internal combustion engine.
In particular, a lubricant formulation formed from a blend of base oils with a defined solvency of the base oil, a volatility below a defined threshold (15% as measured by NOACK), a minimum oxidative stability (above 40 minutes as measured by PDSC) and a base oil viscosity of from about 2 to about 10 cSt can effectively prevent the carbon buildup and remove carbon buildup. The solvency can be measured by various methods, such as, for example, aniline point. Lubricant formulations with a base oil blend having an aniline point of 20-115 and preferably 60, should adequately remove carbon buildup in engines and still exhibit elastomer compatibility.
The base oil formulation is formed by blending Group III and/or Group IV lubricants with higher solvency base oil from Group V in relative amounts to establish the effective solvency, volatility, oxidative stability and base oil viscosity, while remaining compatible with elastomers, providing acceptable corrosion prevention and cleaning of the engine without excessive oil consumption.”