Automobile lubrication system and lubricating oils

1. LUBRICATION SYSTEM

2. Purpose of Lubrication
• Reduce the frictional resistance of the engine to a minimum to
ensure maximum mechanical efficiency.
• Protect the engine against wear.
• Remove all impurities from the lubricated region.
• Form a seal between piston rings and the cylinder walls to prevent
blow-by.
• Serve as a cooling agent by picking up heat.

3. Lubrication Systems
• Mist lubrication system – 2 STROKE
• Wet sump lubrication system – 4 STROKE SMALL ENGINES
• Dry sump lubrication system -4 STROKE

4. MIST LUBRICATION
• In two-stroke engines, the charge is compressed in the crankcase, and as
such it is not suitable to have the lubricating oil in the sump.
• Therefore, such engines are lubricated by adding 3 % to 6 % oil in the fuel
tank itself. The oil and fuel mixture is inducted through the carburetor.
• The fuel gets vaporized and the oil, in the form of mist, goes into the
cylinder through the crankcase.
• The oil that impinges the crankcase walls lubricates the main and
connecting rod bearings, and the rest of the oil lubricates the piston,
piston rings and cylinder.
• The main advantage with this system lies in the simplicity and low cost as
the system does not require any oil pump, filter etc.

5. Wet Sump Lubrication Systems
• the splash and circulating pump system
• the splash and pressure system
• the full force-feed system

10. Properties of lubricant
• 1. Viscosity of fuel – ability of oil film to carry load
• Higher the viscosity more ability to carry load but greater the friction
• Viscosity index
• Paraffin base oil -0 rating
• Napthenic base oil – 100 rating

11. Properties of fluid
• 2. flash point –
• Lowest temp at which oil will flash when a small flame is passed
across it.
• Should be sufficiently high
• 3. Fire point –
• It is lowest temp at which the oil burns continuously.
• Should be sufficiently high.

12. Properties of lubricant
• 4.Cloud point – point at which oil changes from liquid state to plastic
or solid state.
• 5. Pour point –
• Lowest temp at which lubricant will pour.
• Indication of its ability to move at low temp.
• Cold weather important

13. Properties of lubricant
• 6. Oiliness – property enables the fluid to spread over and adhere to
surface to be lubricated.
• 7.Corrosive- should not corrode
• 8.Emulsification – when mixed with water losses its lubricating ability.
• 9.Stability- physical and chemically

14. Properties of lubricant
• 10. Neutralisation number- acidity and alkalinity of an oil
• 11. Adhesiveness –adhere to metal surface
• 12. Film strength – Retain film between two surfaces

15. ADDITIVES IN OIL
• 1. Detergents – effective acid netraliser
• 2. Rust inhibitors
• 3. Viscosity index improver –high molecule polymer
• 4.Pour point additives – Polymerized phenols and ethers
• 5.Anti-foam additives
• Oiliness improvers, Anti-oxidants, Anti wear additives

16. Types of lubricants
• 1.Mineral oils – obtained from crude oil
• 2. Fatty oils – animal and vegetable oils
• Like – fish oil,linseed oil ,olive oil, etc
• Animals oil not generally used as they can burn
• 3. Synthetic oils – Silicon polymers , Silicon esters, Phosphate esters,
• Fluorinated and chlorinated hydrocarbons

17. Classification of lubricating oils
• According to their viscosity
• SAE –Society of Automotive Engineers
• Reference temp 18 to 99 degree celcius
• SAE 5 W, SAE 10 W – 18 DEGREE CELCIUS WINTER OPERATION
• SAE 20, 30 ,40 ----
• Multi-grade oils- SAE 5W/20 , SAE 20W/20
• Advantages of multigrade oil
• 1.no necessity to change the oil as per ambient condition
• 2. required viscosity maintained for long range of temp—long life of engine
• Excellent stability
• Easy starting