The falling point of lubricants

Using viscosity ratios

Authors Name-Arafat Husain

name of organization-Chemical engineering
Name of organization –Aligarh Muslim University
Dept.
Name of country-India
Email-arakant78@gmail.com
Abstract
The lubricants are one of the most used resource in today’s world. Lot of the superpowers are dependent on the lubricant resource for their country to function. To see that the lubricants are not adulterated we need to develop some efficient ways and to see which fluid has been added to the lubricant. So to observe the these malpractices in the lubricant we need to develop a method. We take a elastic ball and throw it at probability circle submerged in the lubricant at a fixed force and see the distance of
pitching and the point of fall .Then we calculate the ratio of distance of falling to the distance of pitching and if the measured ratio is greater than one the fluid is less viscous and if the ratio is lesser than the lubricant is viscous. We will check the falling point of pure lubricant at fixed force and every pure lubricant would have a fixed falling point. After that we would adulterate the
lubricant and note the falling point and if the falling point is less than the standard value then adulterate is solid and if the adulterate is liquid the falling point will be more than the standard value .Hence the comparison with the standard falling point will give the efficiency of the lubricant.
What is a lubricant?
A lubricant is a substance introduced to reduce friction between moving surfaces. It may also have the function of transporting foreign particles. The property of reducing friction is known as lubricity. (Slipperiness)
A good lubricant possesses the following characteristics:
• High boiling point
• Low freezing point
• High viscosity index
• Thermal stability
• Hydraulic Stability
• Corrosion prevention
High resistance to oxidation
One of the single largest applications for lubricants, in the form of motor oil, is protecting the internal combustion engines in motor vehicles and powered equipment.
Typically lubricants contain 90% base oil (most often petroleum fractions, called mineral oils) and less than
10% additives. Vegetable oils or synthetic liquids such as hydrogenated polyolefin ,esters, silicones, fluorocarbons and many others are sometimes used as base oils. Additives deliver reduced friction and wear, increased viscosity, improved viscosity index, resistance to corrosion and oxidation, aging or contamination, etc.
Lubricants such as 2-cycle oil are added to fuels like gasoline which has low lubricity . Sulfur impurities in fuels also provide some lubrication properties, which has to be taken in account when switching to a low-sulfur diesel; biodiesel is a popular diesel fuel additive providing additional lubricity.
Non-liquid lubricants include grease, powders (dry graphite, PTFE, Molybdenum disulfide, tungsten disulfide, etc.), PTFE tape used in plumbing, air cushion and others. Dry lubricants such as graphite, molybdenum disulfide and tungsten disulfide also offer lubrication at temperatures (up to 350 °C) higher than liquid and oil-based lubricants are able to operate. Limited interest has been shown in low friction properties of compacted oxide glaze layers formed at several hundred degrees Celsius in metallic sliding systems, however, practical use is still many years away due to their physically unstable nature.
1) Base oil group
Mineral oil term is used to encompass lubricating base oil derived from crude oil. The American Petroleum Institute (API)
designates several types of lubricant base oil:[2]
• Group I – Saturates <90% and/or sulfur >0.03%, and Society of Automotive Engineers (SAE) viscosity index (VI) of 80 to 120
Manufactured by solvent extraction, solvent or catalytic dewaxing, and hydro-finishing processes. Common Group I
base oil are 150SN (solvent neutral), 500SN, and 150BS (brightstock)
• Group II – Saturates over 90% and sulfur under 0.03%, and SAE viscosity index of 80 to 120
Manufactured by hydrocracking and solvent or catalytic dewaxing processes. Group II base oil has superior anti- oxidation properties since virtually all hydrocarbon molecules are saturated. It has water-white color.
• Group III – Saturates > 90%, sulfur <0.03%, and SAE viscosity index over 120
Manufactured by special processes such as isohydromerization. Can be manufactured from base oil or slax wax from dewaxing process.
• Group IV – Polyalphaolefins (PAO)
• Group V – All others not included above such as naphthenics, PAG, esters. The lubricant industry commonly extends this group terminology to include:
• Group I+ with a Viscosity Index of 103–108
• Group II+ with a Viscosity Index of 113–119
• Group III+ with a Viscosity Index of at least 140
The global lubricant market is generally competitive with numerous manufacturers and marketers. Overall the western market may be considered mature with a flat to declining overall volumes while there is strong growth in the emerging economies. The lubricant marketers generally pursue one or more of the following strategies when pursuing business.
• Specification:
The lubricant is said to meet a certain specification. In the consumer market, this is often supported by a logo, symbol or words that inform the consumer that the lubricant marketer has obtained independent verification of conformance to the specification. Examples of these include the API’s donut logo or the NSF tick mark. The most widely perceived is SAE viscosity specification, likeSAE 10W-40. Lubricity specifications are institute and manufacturer based. In the U.S. institute: API S for petrol engines, API C for diesel engines. For 2007 the current specs are API SM and API CJ-4. Higher second letter marks better oil properties, like lower engine wear supported by tests. In EU the ACEA specifications are used. There are classes A, B, C, E with number following the letter. Japan introduced the JASO specification for motorbike engines. In the industrial market place the
specification may take the form of a legal contract to supply a conforming fluid or purchasers may choose to buy on the basis of a manufacturers own published specification.
• Original equipment manufacturer (OEM) approval:
Specifications often denote a minimum acceptable performance levels. Thus many equipment manufacturers add on their own particular requirements or tighten the tolerance on a general specification to meet their particular needs (or doing a different set of tests or using different/own testbed engine). This gives the lubricant marketer an avenue to differentiate their product by
designing it to meet an OEM specification. Often, the OEM carries out extensive testing and maintains an active list of approved products. This is a powerful marketing tool in the lubricant marketplace. Text on the back of the motor oil label usually has a list of conformity to some OEM specifications, such as MB, MAN, Volvo, Cummins, VW, BMW or others. Manufactures may have vastly different specifications for the range of engines they make; one may not be completely suitable for some other.
• Performance:
The lubricant marketer claims benefits for the customer based on the superior performance of the lubricant. Such marketing is supported by glamorous advertising, sponsorships of typically sporting events and endorsements. Unfortunately broad performance claims are common in the consumer marketplace, which are difficult or impossible for a typical consumer to verify. In the B2B market place the marketer is normally expected to show data that supports the claims, hence reducing the use of broad claims. Increasing performance, reducing wear and fuel consumption is also aim of the later API, ACEA and car manufacturer oil specifications, so lubricant marketers can back their claims by doing extensive (and expensive) testing.

Efficiency:

The lubricant marketer claims improved equipment efficiency when compared to rival products or technologies, the claim is usually valid when comparing lubricant of higher specification with previous grade. Typically the efficiency is proved by showing a reduction in energy costs to operate the system. Guaranteeing improved efficiency is the goal of some oil test specifications such as API CI-4 Plus for diesel engines. Some car/engine manufacturers also specifically request certain higher efficiency level for lubricants for extended drain intervals.
• Operational tolerance:
The lubricant is claimed to cope with specific operational environment needs. Some common environments include dry, wet, cold, hot, fire risk, high load, high or low speed, chemical compatibility, atmospheric compatibility, pressure or vacuum and various combinations. The usual thermal characteristics is outlined with SAE viscosity given for 100°C, like SAE 30, SAE 40. For low temperature viscosity the SAE xxW mark is used. Both markings can be combined together to form a SAE 0W-60 for example. Viscosity index (VI) marks viscosity change with temperature, with higher VI numbers being more temperature stable.
• Economy:
The marketer offers a lubricant at a lower cost than rivals either in the same grade or a similar one that will fill the purpose for lesser price. (Stationary installations with short drain intervals.) Alternative may be offering a more expensive lubricant and promise return in lower wear, specific fuel consumption or longer drain intervals. (Expensive machinery, un-affordable downtimes.)
The importance of lubricant lies in its Quality for a given quantity so the importance to develop easy methods of oil analysis are becoming important. It is important to know oil analys Oil analysis involves sampling and analyzing oil for various properties and materials to monitor wear and contamination in an engine, transmission or hydraulic system. Sampling and analyzing on a regular basis establishes a baseline of normal wear and can help indicate when abnormal wear or contamination is occurring.
Oil analysis works like this. Oil that has been inside any moving mechanical apparatus for a period of time reflects the exact condition of that assembly. Oil is in contact with engine or mechanical components as wear metallic trace particles enter the oil. These particles are so small they remain in suspension. Many products of the combustion process also will become trapped in the circulating oil. The oil becomes a working history of the machine.
Particles caused by normal wear and operation will mix with the oil. Any externally caused contamination also enters the oil. By identifying and measuring these impurities, you get an indication of the rate of wear and of any excessive contamination. An oil analysis also will suggest methods to reduce accelerated wear and contamination.

a) The typical oil analysis tests for the presence of a number of different materials to determine sources of wear, find dirt and other contamination. Oil analysis can detect:

• Fuel dilution of lubrication oil
• Dirt contamination in the oil
• Antifreeze in the oil
• Excessive bearing wear
• Misapplication of lubricants
Some wear is normal, but abnormal levels of a particular material can give an early warning of impending problems and possibly prevent a major breakdown.
THE EXPERIMENT-
The experiment was conducted to determine the falling point of lubricant as a part of oil analysis in terms of Dynamic ratio of (distance of fall after pitching on probability circle/distance of ball pitching on the probability circle on the fluid or lubricant). The standard Dynamic ratio is taken to be that of water at different temperature to be considered as viscous or non viscous lubricants
.
Apparatus required were –a elastic ball ,a system to produce a constant force ,a lubricant (both in a pure and impure state )
about 1 litre ,a surface with known viscosity.
• Observation –The Dynamic ratio of water comes out to be more than 1.
• The Dynamic ratio of gasoline was found to be more than that of the water so it is a blind test for characterization of phase of lubricant.
• The dynamic ratio was found to be less than 1 so it is considered to be a solid lubricant.
From these observations one can say that falling point helps in not only identifying the lubricants but also classifying them. Adding impurities to the lubricants helps to observe that when impurities added to lubricants there is a observable change in falling point of lubricant . When a solid impurity was added to gasoline there was decrease in the falling point . When liquid impurity was added to gasoline of less viscosity than there is an increase in the falling point of gasoline.
The deviation is not significant but between a range of 0-15cm for a fixed force.
Conclusion can be reached that falling point of oil not only tells us the phase but as well as the impurities in the lubricant as well as the efficiency of lubricant. Formula used for fall point on the basis of impurities used.
For solid impurity used ,let the fall point be x then= x-negative deviation=distance less than falling point for liquid impurity used=x+ positive deviation=distance more than falling point
Records show that some equipment can safely run two or three times longer than recommended intervals. The oil analysis may show that you are changing the oil more often than necessary — or not often enough.
By eliminating too frequent oil changes, you reduce the cost for oil and servicing and also reduce the amount of used oil to deal with. This is an important pollution prevention method — reducing the source!
Oil sample analysis saves you repair and maintenance dollars, has the potential to reduce used oil and increases resale value of equipment.
These are average numbers used but depending on your type of equipment may be higher or lower. Most reports have charts listed on the back to explain the severity of that component in ppm.

Table I. Engine problems predicted with oil analysis.

Indicator Acceptable

Levels

Engine Problem What to Check

Silicon (Si) and

Aluminum(Al)

10 to 30 ppm

Dirt ingestion Air intake system, oil filter plugging, oil filler cap and breather, valve covers, oil supply

Iron (Fe) 100 to 200 ppm

Wear of cylinder liner, valve and gear train, oil pump, rust in system

Excessive oil consumption, abnormal engine noise,performance problems, oil pressure, abnormal operating temperatures, stuck/broken piston rings

Chromium(CR) 10 to 30 ppm

Piston ring wear Excessive oil blow-by and oil consumption, oil degradation

Copper (CU) 10 to 50 ppm

Bearings and bushings wear, oil cooler passivating,radiator corrosion

Coolant in engine oil, abnormal noise when operating at near stall speed

Lead (Pb)* 40 to 100 ppm

Bearing corrosion Extended oil change intervals

Copper (CU)

and

Lead (Pb)*

10 to 50 ppm

Bearing lining wear Oil pressure, abnormal engine noise, dirt being ingested in air intake, fuel dilution, extended oil drain intervals

Aluminum(Al) 10 to 30 ppm

Piston and piston thrust bearing wear

Blow-by gases, oil consumption, power loss, abnormal engine noise

Silver and

Tin

Viscosity

Change

2 to 5 ppm

10 to 30 ppm

Wear of bearings Excessive oil consumption, abnormal engine noise, loss in oil pressure

Lack of lubrication Fuel dilution, blow-by gases, oil oxidation, carburetor choke, ignition timing, injectors, injector pump, oil pressure

Water/Anti- freeze

Coolant leak or condensation

Coolant supply, gasket sealed, hose connection, oil filler cap and breather

* Significant as wear metal, only for engines using unleaded and diesel fuel.

Figure 1. Example of oil analysis report.

OIL TEST RESULTS

UNIT NO 99999: OIL USED: EL CHEAPO SAE GRADE:20 COMPONENT:ENGINE COOLANT:GLYCOL MAKE:TT MODEL:C-60 ENGINE MANUF:CHEVROLET HORSE POWER:427 FUEL TYPE:GASOLINE

RECOMMENDATIONS FOR LAST SAMPLE ANALYSIS

EXCESSIVE FUEL DILUTION

OIL IN SAE 10W GRADE RANGE CHECK BLOW-BY (COMPRESSION) DRAIN OIL

RESAMPLE AT NORMAL INTERVAL CHECK FUEL PUMP

MAINTENANCE RECORD:

VIS
SAMPLE
DATE
DATE
MI/HR
MI/HR
MI/HR
MI/HR
QTS
@ FUEL
ANTI-
TOTAL
OXIDA- TOTAL
NUMBER SAMPLE RECEIVED
OIL
FILTER
NEW
OVHL
OIL
ADDED
100
C
DILUTE WATER FREEZE SOLIDS
TION
ACID
NO.
18 011693 011993 02100 02100 122826 012000 0 8.8 <1.0 NIL NEG 1.8 0.1 4.2

NTAMINANTS:

N CHROMIUM ALUMI- COPPER LEAD TIN SILVER NICKEL SILI- SODIUM BORON MAG-
CALCIUM BARIUM PHOSPHO- Z
NUM
CON
NESIUM
RUS

RECOMMENDATION:

As a result of the excessive fuel dilution, the oil has been lowered one SAE grade, and we are seeing upper cylinder wear.

Sources- Wikipedia, SAE grading, Acknowledgement-Moina mam

.