WO2009152117A1

WO2009152117A1 - Lubricants for air donditioning systems

Info

Publication number: WO2009152117A1
Application number: PCT/US2009/046674
Authority: WO
Inventors: Terrence D. Kalley; Barry J. Harrison
Original assignee: Bright Solutions International Llc
Priority date: 2008-06-09
Filing date: 2009-06-09
Publication date: 2009-12-17
Also published as: CN102119313A; US20110190184A1

Abstract

Lubricants for air conditioning systems in hybrid vehicles can be high dielectric lubricants.

Description

LUBRICANTS FOR AIR CONDITIONING SYSTEMS

CLAIM FOR PRIORITY

This application claims priority to U.S. Provisional Patent Application No. 61/059,892, filed on June 9, 2008, which is hereby incorporated by reference in its entirety.

TECHNICAL FIELD

This invention relates to lubricants for air conditioning systems in hybrid vehicles.

BACKGROUND

Regular vehicle manufacturers have used polyalkylene glycols (PAGs) as a compressor lubricant with refrigerant for many years. PAGs are chosen over polyolesters (POEs) due to superior performance characteristics such as protection against wear and greater thermal and chemical stability. Further, PAGs have superior hydrodynamic lubricity, better low temperature properties, superior chemical stability, superior hydrolytic stability and better elastomers and plastic compatibilities. In addition, the viscosity of a PAG is retained over broader temperature ranges as measured via a viscosity index. However, the hybrid car industry perceives PAGs as having a distinct technical disadvantage compared to POE as PAGs have high water absorption and poor electrical resistivity properties.

The use of PAGs is especially disadvantageous when used as a lubricant in air conditioning systems powered by high voltage electrical systems (typically battery voltages between 144-330 volts) in hybrid vehicles, more specifically when used in electrically driven compressors. In circuits with a boost converter, the battery pack voltages can double. There are also so-called "mild hybrids" using 42 volt systems such as the 2008 Saturn Vue and Aura and the 2008 Chevrolet Malibu. Such high voltage in these electrical systems results in risks to technicians in certain situations including when servicing these hybrid vehicles and to other persons such as emergency responders in accident situations. There is also risk of damage to the A/C system and its components such as a compressor and possibly with the recovery and recycling equipment used to service A/C systems. SUMMARY

Advantageously, high dielectric lubricants with low or no water content and low conductivity can be used in air-conditioning systems in hybrid vehicles to reduce or eliminate risks to subjects in contact with such vehicles. In one aspect, a method of dehydrating a lubricant in an air conditioning system of an electric compressor can include introducing a water scavenger into the system of the electric compressor. The electric compressor can be in a hybrid vehicle. The lubricant can be polyalkylene glycol or polyolester. The method can further include introducing an additive into the system. The additive can include a leak detection dye, a leak stop additive, or a performance-enhancing product. The additive can be a leak detection dye and the lubricant can be polyalkylene glycol. The additive can have high dielectric strength. The water scavenger can be added to the lubricant prior to introduction of the compressor lubricant to the system of the hybrid vehicle. The water scavenger can be an organometallic compound or an organometalloid compound. The method can further include introducing an indicator compound that indicates the presence of water in the system. The indicator compound can be a compound that fluoresces in the presence of water or shows a change in color or odor in the presence of water.

In another aspect, a method of minimizing or eliminating the risk of an electrical shock to a subject in contact with systems in a hybrid vehicle can include introducing a high dielectric lubricant into the air-conditioning system of the hybrid vehicle wherein the lubricant is a polyalkylene glycol and has a water content of below 500 ppm. The polyalkylene glycol can have a water content of below 300 ppm. The polyalkylene glycol can have a water content of below 50 ppm. The polyalkylene glycol can have a total acid number of <0.1 mgKOH/g. The polyalkylene glycol can have a total acid number of <0.1 mgKOH/g.

In a further aspect, a method of minimizing or eliminating the risk of an electrical shock to a subject in contact with systems in hybrid vehicle can include introducing a high dielectric lubricant into the air-conditioning system of the hybrid vehicle wherein the lubricant has a volume resistivity between 6 X 10ⁿ to 12 X 10ⁿ ohm cm. The lubricant can have a volume resistivity between 10 X 10ⁿ to 12 X 10ⁿ ohm cm. The lubricant can have a water content of below 50 ppm. The method can include introducing the high dielectric lubricant into the air-conditioning system of the hybrid vehicle includes using an injection device. The high dielectric lubricant can include a leak detection dye. In one aspect, a method of minimizing or eliminating the risk of an electrical shock to a subject in contact with systems in hybrid vehicle can include introducing a high dielectric lubricant into the air-conditioning system of the hybrid vehicle wherein the lubricant has a dielectric strength between 35-40 kV. The lubricant can have a water content of below 50 ppm. The method can include introducing the high dielectric lubricant into the air-conditioning system of the hybrid vehicle includes using an injection device. The high dielectric lubricant can include a leak detection dye.

In one aspect, a method of minimizing or eliminating the risk of an electrical shock to a subject in contact with systems in a hybrid vehicle can include introducing a high dielectric lubricant into the air-conditioning system of the hybrid vehicle wherein the lubricant has a dielectric strength between 35-40 kV and a volume resistivity of at least 1 x 10¹² ohm cm. The lubricant can be polyalkylene glycol. The lubricant can be polyolester. The method can further include g introducing an additive into the system. The additive can include a water scavenger, a leak detection dye, a leak stop additive, or a performance-enhancing product. The additive can have high dielectric strength.

The water scavenger can be added to the lubricant prior to introduction of the compressor lubricant to the system of the hybrid vehicle. The water scavenger can be an organometallic compound or an organometalloid compound. The method can further include introducing an indicator compound that indicates the presence of water in the system. The indicator compound can be a compound that fluoresces in the presence of water. The method can further include introducing an indicator compound that indicates that the lubricant is a high dielectric lubricant. The indicator compound can be a compound that can be differentiated visually. The indicator compound can be a compound that can be differentiated though an odor. The method can include introducing the high dielectric lubricant into the air-conditioning system of the hybrid vehicle includes using an injection device. The high dielectric lubricant can include a leak detection dye.

In another aspect, a method of minimizing or eliminating the risk of an electrical shock to a subject in contact with systems in hybrid vehicle can include introducing a high dielectric lubricant into an air-conditioning system of the hybrid vehicle wherein the lubricant has a dielectric strength between 35-40 kV and block weight loss of more than 30 mg in a modified Falex test in R- 134a atmosphere using aluminum pins and blocks per ASTM D3233 at 200 Ib for 60 seconds. The method can include introducing the high dielectric lubricant into the air-conditioning system of the hybrid vehicle includes using an injection device. The high dielectric lubricant can include a leak detection dye. The details of one or more embodiments are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the invention will be apparent from the description and drawings, and from the claims.

DESCRIPTION OF DRAWINGS

Fig. 1 is a graph depicting the results of a basic hygroscopicity test demonstrating the water content of Zerol RFL and Idemitsu dicapped PAG at different time points. Fig. 2A is a graph depicting the volume resistivity of Zerol RFL and Idemitsu dicapped PAG when the total acid number (TAN) constant for all samples is at 0.03 mgKOH/g.

Fig. 2B is a graph depicting the volume resistivity of Zerol RFL and Idemitsu dicapped PAG when the water content constant for all samples is at 50 ppm. Fig. 3 is a graph depicting the results of a modified Falex Test in R- 134a atmosphere.

DETAILED DESCRIPTION

To minimize or eliminate the risk of an electrical shock to subjects in contact with systems in hybrid or electric cars and/or to limit damage to such systems and/or their components, lubricants with low conductivity or high resistivity can be introduced into the air conditioning systems of hybrid or electric vehicles. Systems in hybrid cars can include air-conditioning (A/C) systems or climate control systems. Subjects who are in contact with such systems can include technicians who are servicing such vehicles or emergency responders who are responding to an emergency situation involving such vehicles or vehicle operators involved in such emergency situations or workers involved with the assembly of A/C systems or the assembly of hybrid or electric vehicles.

In addition to the fear of electrical shock, there is also the fear of cross contamination of A/C system caused by using a lubricant not intended for use in a particular system. Since about 1993 almost all vehicle worldwide have used PAGs as their compressor lubricants. These compressors will perform less than optimally and may experience a reduced life with another lubricant such as a POE and may actually experience failure with the wrong lubricant. With the current use of POEs in electrical and/or hybrid vehicles, there is a fear that these POEs might inadvertently find there way into vehicles for which PAGs are the original equipment manufacturer (OEM) specified lubricant. This may occur in a production/assembly environment or during service. This may be the result of selecting the incorrect lubricant container or of using a dispensing device such as a hand-held injector or an injection device which is part of a recovery and recycling machine or an injection device which is part of the lubricant insertion process during manufacturing or assembly which has some or all of its contents of the incorrect lubricant type.

Similarly, the use of a PAG with high moisture content in a hybrid or electrical system where a lower moisture POE is specified for usage, may result in cross contamination with severe consequences for individuals and systems as previously outlined. As a consequence, the SAE specification for contamination, currently at 1%, is being revised down to 0.1%. Denso has shown that 1% of PAG oil (such as its ND8) in an electric motor-drive compressor system lowers resistance to about 1 megaohm, well below the over- 10 megaohm provided by the usage of 100% of its NDIl oil, a POE. See Figure 2 of Weissler, Peter, "Hybrid oils, trace dyes and the cross-contamination issue- Special recovery/recycle/recharge techniques required when servicing hybrids with electric-drive compressors." MACS Service Reports, p. 1-8. March 2008 issue, which is incorporated by reference in its entirety.

The ideal scenario for the A/C industry is to have one compressor lubricant that can service the needs of existing R- 134a systems designed for using PAGs as well as future systems for electrical or hybrid vehicles with their needs for high dielectric strength lubricants. A high resistivity PAG would be able to meet the needs of both market segments. This high resistivity PAG would have the added benefits versus POEs of superior performance characteristics such as protection against wear and greater thermal and chemical stability, superior hydrodynamic lubricity, better low temperature properties, superior chemical stability, superior hydrolytic stability and better elastomers and plastic compatibilities.

In one embodiment, high dielectric lubricants with low water content, low conductivity or high resistivity can be used. For example, the high dielectric lubricant can have a low water content of less than 2000 ppm, less than 1500 ppm, less than 1000 ppm, less than 500 ppm, less than 300 ppm, less than 250 ppm, less than 100 ppm or less than 50 ppm. The high dielectric lubricant can have a volume resistivity of between 10 X 10¹¹ to 12 X 10¹¹ ohm cm, 8 X 10¹¹ ohm cm to 10 X 10¹¹ ohm cm, between 6 X 10¹¹ ohm cm to 8 X 10¹¹ ohm cm or between 6 X 10ⁿ ohm cm to 12 X 10ⁿ ohm cm. The high dielectric lubricant can have a dielectric strength of between 30-35 kV, between 35-40 kV or between 40-45 kV. Examples of such lubricants can include double end-capped PAGs. Such PAGs can be asymmetrically capped PAGs and can be further additised. The PAGs can have a total acid number (TAN) of below 0.5 mgKOH/g or below 0.1 mgKOH/g. The PAGs can have a total acid number of 0.03 mgKOH/g. Alternatively, a suitable PAG can be chosen based on a combination of TAN/water content specification. Examples of capped PAGs are described in U.S. Patent No. 6,374,629, which is incorporated by reference in its entirety. Examples of such PAGs include Zerol RFL-X or Zerol HYPAG 46 distributed by Shrieve Chemical Company, Houston, Texas and manufactured by Cognis U.K. Ltd.)

In a further embodiment, risks to a subject in contact with high voltage systems in a hybrid or electric vehicle can be reduced by introducing a water scavenger into the system or the lubricant that can bind or otherwise react with water before or after the lubricant is introduced into the system. This can have the effect of dehydrating the system or the oil. In one embodiment, the lubricant can be packaged for injection during servicing into containers which are sealed or devoid of air, or into containers which contain an inert dry gas, such as nitrogen, or a water scavenger or a combination of inert dry gas and a water scavenger. Examples of lubricants can include but are not limited to, a hydrocarbon such as natural or refined mineral oil, a synthetic hydrocarbon (SHC), an alkylbenzene (AB), a polyalphaolefin (PAO), a synthetic polyalkylene glycol, for example, that can be terminated as mono- or diethers or as esters, and a general class of polyolester lubricant, for example, that can be either di-, tri-, tetra- or polyfunctional pentaerythritol esters. Containers can include metal containers including those made largely of tin and plastic containers either rigid in construction or more formless, such as a bag. Plastic containers may be constructed of high density polyethylene, may include a barrier seal, and may include nylon or any other suitable material to protect the contents from moisture. The containers may be attachable to injection devices, which may be constructed in such a way as to minimize moisture invasion. Such injection devices my be attachable to the port of an A/C or refrigeration system or to a recovery and recycling machine or to a manifold gauge set or to a hose or other fluid conduit connected to any of the aforementioned systems, machines or devices.

Examples of water scavengers can include organometalloid and/or organometallic compounds as described in U.S. Patent No. 5,882,543, which is incorporated by reference in its entirety. Other methods of removing water are described in U.S. Pat. Nos. 4,304,805, 4,331,722, 4,379,067, 4,442,015 and 4,508,631 of Packo et al. which teaches the use of silicon-containing compounds including certain mercaptosilanes, acyloxysilanes, aminosilanes, and alkoxysilanes in conjunction with acetic anhydride or aminosilanes. In one embodiment, the water scavengers can be used to dehydrate a lubricant before or while adding a leak stop additive which can prevent the water scavenger from being activated prematurely by the moisture present in the air- conditioning system. Examples of leak stop additives are described in U.S. Patent No. 5,882,543 entitled "Compositions and methods for dehydrating, passivating and sealing systems," which is incorporated by reference in its entirety. An example of a water scavenger used includes dimethyldimethoxysilane in BSL471 from Bright Solutions.

It may be useful to use water scavengers with high flash points of between 150 to 300 degrees Fahrenheit, which can be beneficial for safety purposes in an operating environment and to meet less stringent and less costly shipping regulations. An example of a high-flash point water scavenger includes octylmethyldiethoxysilane, which has a flash point in excess of 200 degrees Fahrenheit. Other examples include phenylmethydimethoxysilane with a flash point of approximately 168 degrees Fahrenheit and diphenyldimethoxysilane with a flash point of approximately 250 degrees Fahrenheit. The water scavenger can have the ability to react with water and thereby sequester it from the A/C system. The by-product of this reaction can preferably have good lubricating properties. More preferably, the by-product can be some form of silicon lubricant. The by-product can be of high resistivity.

The presence of water or moisture in an air conditioning system can be determined by an indicator compound that provides colored visual indication such as fluorescence. Examples of such indicator compounds can include DF5301 Yellow Industrial Water Dye manufactured and sold by Corrosion Consultants Inc. in

Bloomington, MN. Other suitable indicator compounds that fluoresce in the presence of moisture or water may be used. Examples of indicator compounds can include providing an odorant in a water soluble matrix or barrier such that the presence of water or moisture causes the water soluble matrix or barrier to dissolve releasing the odorant as described in U.S. Patent No. 6,063,632, which is incorporated by reference in its entirety. Other suitable indicator compounds that release an odor in the presence of moisture or water may be used.

In another embodiment, an additive can be added together with the lubricant and the water scavenger into the air conditioning system of a hybrid vehicle or the water scavenger may be absent. The additive can be oil, leak detection dye, or a performance- enhancing product, for example, a substance that prolongs the life of the system, a system component, or an assembly of system components. The additive can further include leak stop agents, air-conditioning temperature lowering additives, refrigerant, a leak stop additive for metal leaks, a leak stop additive for elastomeric leaks and an additive for conditioning o-rings. One or more of the additives can be introduced together with the lubricant and the water scavenger. All additives can be of high-resistivity and should preferably have high resistivity. Should more than one additive be added to a system at a time, the additives should preferably work simultaneously and synergistically to meet several goals related to safety and performance.

The additive can include a silane such as dimethyldimethoxysilane, aminoethylaminopropyltrimethoxysilane, aminopropyltrimethoxysilane, dimethyldimethoxysilane, octylmethyldiethoxy silane, or vinyltrimethoxysilane, or a combination thereof, which can be present in an amount between 0.1 and 1 weight percent of the total composition.

In one embodiment, the lubricant and the water scavenger can be part of a leak detection dye composition that is introduced into a climate control system or the water scavenger may be absent. The climate control system can be a mobile, stationary, window air conditioning system such as a hybrid or electric vehicle, portable, residential, or commercial air conditioning system or any other hermetic system that employs a refrigerant and a lubricant. After the composition has been loaded into the climate control system, the system can be operated to circulate the composition throughout the system. The circulating refrigerant can also disperse the composition throughout the system. Typically the leak detection dye content of the system can be below about 0.1 percent. After the dye has been allowed to circulate within the system, the system joints, components, or attachments can be examined with a light source having a wavelength from 190 nanometers to 700 nanometers. The presence of a leak can be determined by a colored visual indication such as fluorescence or other light emission that can be detected after excitation with the light from the light source. Alternatively, if the leak detection composition includes a visible leak detection dye, visible to the unaided eye, the presence of the leak can be determined by visual inspection of the climate control system. The leak detection dye composition that includes a lubricant and a water scavenger can be supplied in the form of a pressurized canister, a hose, a container, or any other fluid transfer or storage apparatus. The refrigerant can include chlorofluorocarbons, hydrochlorofluorocarbons, hydrofluorocarbons, carbon dioxide, ammonia, halogenated or ether derivatives of methane or ethane, or halogenated ether or cyclic derivatives of propane, butane, or other hydrocarbons. Examples of a refrigerant include 1,1,1,2 tetrafluoroethane (R- 134a, Honeywell),dichlorodifluoromethane (R- 12, DuPont,

Wilmington, DE) and experimental refrigerants such as those under development by DuPont and Honeywell to replace R- 134a refrigerant. The lubricant can include polyalkylene glycols, polyolesters, mineral oils, polyvinyl ethers, alkylbenzenes, or other synthetic lubricating materials. The dye concentrate can include leak detection dye such as a fluorescent dye. The fluorescent dye can include a naphthalimide dye, a perylene dye, a coumarin dye, a thioxane dye, a fluorescein dye, or a derivative thereof or other dye compatible with a climate control systems. The fluorescent dye can be liquid or solid, such as a powder. Examples of suitable dyes include liquid dyes, for example, STAY- BRITE BSL 714 (Bright Solutions, Troy MI), DAY GLOW TRY-33 or TRY-53 (Day Glow Color Corp, Cleveland, OH), R-12 Dye STAY-BRITE BSL713 (part

B713012), or R-134a Dye STAY-BRITE BSL712 (part B712012) or other dyes. The dyes can include a POE lubricant such as B714012 or be a so-called solvent-free dye such as B703012 (both from Bright Solutions) which is composed of a dye and lubricant without any further material amounts of another co-solvent. The dye can be combined with a low conductivity lubricant, for example a PAG, POE or PAO, and can also include a water scavenger in the formulation. The formulation can be the result of a reaction, mixture or other combination of constituents.

In one embodiment, the composition can be a combination of a refrigerant, a lubricant, and a dye concentrate. The composition can include, for example, a first weight amount of leak detection dye concentrate, a second weight amount of lubricant and a third weight amount of refrigerant. The first and second amounts together can be greater than the third amount. See, for example, U.S. Patent No. 6,183,663, which is incorporated by reference in its entirety.

The performance-enhancing product can extend the lifetime of the system or give new life to bearings, seals, and all compressor parts, increase cooling capacity, quiet compressor noise, or decrease fuel consumption by reducing friction, thereby improving the compressor's mechanical efficiency and lowering its power consumption. The product may have the effect of reducing the temperature that comes out of the vents. The product can coat the parts better than existing lubricants resulting in longer life for the compressor and certain components. See, for example, U.S. Patent No. 7,077,149, which is incorporated by reference in its entirety.

To reduce the possibilities of cross contamination, the high resistivity lubricant, such as a PAG, POE or PAO, can be differentiated from other lubricants by a distinctive colorant or an odorant. The colorant can be fluorescent. The colorant an be a dye, a colorant or an optical brightener. Currently PAGs and POEs are clear liquids, with the exception of at least one PAG which has a blue color. The differentiating colorant can be of high electrical resistivity. This visual differentiation should be capable of distinguishing a high resistivity lubricant (with or without additives) from a regular/low resistivity lubricant.

EXAMPLES

Experiments were conducted comparing Zerol RFL with ISO 100 Idemitsu dicapped PAG obtained from Idemitsu Lubricants America Corporation (Jeffersonville, Indiana). Fig. 1 depicts the results from a basic hygroscopicity test conducted at 80% relative humidity, 25 ⁰C and on 25 cm² surface area. The test demonstrates that Zerol RFL has lower water content than a dicapped PAG from Idemitsu.

Further experiments were conducted to investigate the influence of water content and TAN value on electrical resistivity of dicapped PAGs. As shown in Figs. 2A and B, extensive testing demonstrated differences in resistivity between commercially available dicapped PAGs. This can be attributed to additisation type and production quality, for example residual catalyst rather than differences in PAG structure. Fig. 2A is a graph that is measured on samples which have a total acid number (TAN) (mgKOH/g) set at 0.03 mgKOH/g. The effect of varying water content in these samples is presented in the plot with resistivity decreasing as expected when the water content increases. There is a marked difference between Zerol RFL with ISO 100 Idemitsu dicapped PAG for samples which have identical TAN and water content. However, this is thought to be due to the salt content of the samples. Salt can be a bi-product of PAG manufacture and samples which have higher salt contents will show poorer electrical resistivity. Fig. 2B is a graph that is measured on samples which have a water content set at 50 ppm. The effect of varying TAN in these samples is shown with higher TAN and decreased resistivity. There is a difference between Zerol RFL with ISO 100 Idemitsu dicapped PAG, particularly at low TAN which is most likely due to salt content. Table 1

Table 1 is a comparison of different PAGs and their volume resistivity and dielectric strength. As demonstrated, Zerol HYPAG 46 offers an optimized PAG basestock for R- 134a systems, combined with appropriate additisation technology, and can be manufactured to the appropriate water specification to ensure optimized electrical properties suitable for hybrid MAC systems.

Fig. 3 is a graph showing the results o f a modified Falex test (in R- 134a atmosphere) showing the superiority of PAGs versus POEs. The graph demonstrates that an oil can be defined in terms of its block weight loss.

Other embodiments are within the claims.

Claims

WHAT IS CLAIMED IS:

1. A method of dehydrating a lubricant in an air conditioning system of an electric compressor comprising introducing a water scavenger into the system of the electric compressor.

2. The method of claim 1 , wherein the electric compressor is in a hybrid vehicle.

3. The method of claim 1, wherein the lubricant is polyalkylene glycol.

4. The method of claim 1, wherein the lubricant is polyolester.

5. The method of claim 1, further comprising introducing an additive into the system.

6. The method of claim 5, wherein the additive includes a leak detection dye, a leak stop additive, or a performance-enhancing product.

7. The method of claim 5, wherein the additive is a leak detection dye and the lubricant is polyalkylene glycol.

8. The method of claim 5 , wherein the additive has high dielectric strength.

9. The method of claim 1, wherein the water scavenger is added to the lubricant prior to introduction of the compressor lubricant to the system of the hybrid vehicle.

10. The method of claim 1, wherein the water scavenger is an organometallic compound.

11. The method of claim 1, wherein the water scavenger is an organometalloid compound.

12. The method of claim 1, further comprising introducing an indicator compound that indicates the presence of water in the system.

13. The method of claim 12, wherein the indicator compound is a compound that fluoresces in the presence of water.

14. A method of minimizing or eliminating the risk of an electrical shock to a subject in contact with a system in a hybrid vehicle comprising introducing a high dielectric lubricant into the air-conditioning system of the hybrid vehicle wherein the lubricant is a polyalkylene glycol and has a water content of below 500 ppm.

15. The method of claim 14, wherein the polyalkylene glycol has a water content of below 300 ppm.

16. The method of claim 14, wherein the polyalkylene glycol has a water content of below 50 ppm.

17. The method of claim 14, wherein the polyalkylene glycol has a total acid number of <0.1 mgKOH/g.

18. The method of claim 15, wherein the polyalkylene glycol has a total acid number of <0.1 mgKOH/g.

19. The method of claim 14, wherein introducing the high dielectric lubricant into the air-conditioning system of the hybrid vehicle includes using an injection device.

20. The method of claim 19, wherein the high dielectric lubricant includes a leak detection dye.

21. A method of minimizing or eliminating the risk of an electrical shock to a subject in contact with a system in a hybrid vehicle comprising introducing a high dielectric lubricant into an air-conditioning system of the hybrid vehicle wherein the lubricant has a volume resistivity between 6 X 10ⁿ to 12 X 10ⁿ ohm cm.

22. The method of claim 21, wherein the lubricant has a volume resistivity between

10 X 10ⁿ to 12 X 10ⁿ ohm cm.

23. The method of claim 21, wherein the lubricant has a water content of below 50 ppm.

24. The method of claim 21, wherein introducing the high dielectric lubricant into the air-conditioning system of the hybrid vehicle includes using an injection device..

25. The method of claim 24, wherein the high dielectric lubricant includes a leak detection dye.

26. A method of minimizing or eliminating the risk of an electrical shock to a subject in contact with a system in a hybrid vehicle comprising introducing a high dielectric lubricant into an air-conditioning system of the hybrid vehicle wherein the lubricant has a dielectric strength between 35-40 kV.

27. The method of claim 26, wherein the lubricant has a water content of below 50 ppm.

28. The method of claim 26, wherein introducing the high dielectric lubricant into the air-conditioning system of the hybrid vehicle includes using an injection device..

29. The method of claim 28, wherein the high dielectric lubricant includes a leak detection dye.

30. A method of minimizing or eliminating the risk of an electrical shock to a subject in contact with a system in a hybrid vehicle comprising introducing a high dielectric lubricant into an air-conditioning system of the hybrid vehicle wherein the lubricant has a dielectric strength between 35-40 kV and a volume resistivity of at least 1 x 10¹² ohm cm.

31. The method of claim 30, wherein the lubricant is polyalkylene glycol.

32. The method of claim 30, wherein the lubricant is polyolester.

33. The method of claim 30, further comprising introducing an additive into the system.

34. The method of claim 33, wherein the additive includes a water scavenger, a leak detection dye, a leak stop additive, or a performance-enhancing product.

35. The method of claim 34, wherein the additive has high dielectric strength.

36. The method of claim 30, wherein a water scavenger is added to the lubricant prior to introduction of the compressor lubricant to the system of the hybrid vehicle.

37. The method of claim 36, wherein the water scavenger is an organometallic compound.

38. The method of claim 36, wherein the water scavenger is an organometalloid compound.

39. The method of claim 36, further comprising introducing an indicator compound that indicates the presence of water in the system.

40. The method of claim 39, wherein the indicator compound is a compound that fluoresces in the presence of water.

41. The method of claim 36, further comprising introducing an indicator compound that indicates that the lubricant is a high dielectric lubricant.

42. The method of claim 41, wherein the indicator compound is a compound that can be differentiated visually.

43. The method of claim 41, wherein the indicator compound is a compound that can be differentiated though an odor.

44. The method of claim 30, wherein introducing the high dielectric lubricant into the air-conditioning system of the hybrid vehicle includes using an injection device.

45. The method of claim 44, wherein the high dielectric lubricant includes a leak detection dye.

46. A method of minimizing or eliminating the risk of an electrical shock to a subject in contact with a system in a hybrid vehicle comprising introducing a high dielectric lubricant into an air-conditioning system of the hybrid vehicle wherein the lubricant has a dielectric strength between 35-40 kV and block weight loss of more than 30 mg in a modified Falex test in R-134a atmosphere using aluminum pins and blocks per ASTM D3233 at 200 Ib for 60 seconds.

47. The method of claim 46, wherein introducing the high dielectric lubricant into the air-conditioning system of the hybrid vehicle includes using an injection device.

48. The method of claim 46, wherein the high dielectric lubricant includes a leak detection dye.