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Lubrication system

lubrication system automobile

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Lubrication system

  1. 1. Internal Combustion Engines Presented by – Manmeet Singh Assistant Professor 1
  2. 2. Purpose of Lubrication  Reduce the frictional resistance Protect the engine against wear. Serve as a cooling agent by picking up heat. Remove all impurities from the lubricated region. Form a seal between piston rings and the cylinder walls to prevent blowby. 2
  3. 3. Lubrication Systems ❖ Mist lubrication system❖ Wet sump lubrication system ❖ Dry sump lubrication system Four Stroke Engines 3 Two Stroke Engines The wet sump system is employed in relatively small engines, such as automobile engines, While the dry sump system is used in large stationary, marine and aircraft engines.
  4. 4. Mist Lubrication Systems 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 main advantage with this system lies in the simplicity and low cost as the system does not require any oil pump, filter etc. 4
  5. 5. WET SUMP LUBRICATION SYSTEMS 5 In the wet sump system, the bottom of the crankcase contains an oil sump (or pan) that serves as the oil supply reservoir. Oil dripping from the cylinders and bearings flows by gravity back into the wet sump where it is picked up by a pump and re- circulated through the engine lubricating system. The types of wet sump systems used are: 1. the splash and circulating pump system 2. the splash and pressure system 3. the full force-feed system
  6. 6. SPLASH AND CIRCULATING PUMP SYSTEMD:IDM VIDEODOWNLOADEDMPEONLINE - 18-SPLASH LUBRICATION.SWF.MP4 6 C a m s ha f t C o n n e c tin g ro d be a ri n g s M a in be a r in g m a in b e a rin g O il trou g h s Lo w e r o il p a n O il p u m p O il S t r a iner
  7. 7. SPLASH AND PRESSURE SYSTEM 7 C a m s h a ft C o n n e c tin g ro d be a rings M a in be a r in g m a in be a rin g O il p u m p O il S t r a iner
  8. 8. FULL FORCE FEED SYSTEMD:IDM VIDEODOWNLOADEDAUTOMOTIVE BASICS - HOW ENGINE LUBRICATION SYSTEM WORKS.MP4 Camshaft Oil pump Oil Strainer Header main line bearing End leakage from rod connecting rod bearing Main bearing 8
  9. 9. DRY SUMP LUBRICATING SYSTEM 9 Oil Cooler Pressure release valve Vent Filter By-P ass Presuure relief valve Filter Scavenging pum p Strainer E ngine crankcase Oil pum p To Bearings Supply Tank D ry sump
  10. 10. Properties of Lubricating Oil ❖The oil used in an engine must serve as a lubricant, a coolant and an agent for removing impurities. ❖It must be able to withstand high temperatures without breaking down. The oil must operate over a good range of temperature. ❖They must not oxidize on the chamber walls, piston crown or at the piston rings. 10 Oil shoul d have high fil m strength to prevent metal-to-metal contact even under extreme loads.
  11. 11. PROPERTIES OF LUBRICATING OIL 11 (a)Viscosity: The lubricating oil should have the correct viscosity so that it flows easily to all the moving parts. ❖If oil viscosity is too high, more work is required to pump it and to shear it between the moving parts. This results in greater friction work, reduced brake work and hence reduced power output. ❖Viscosity is highly on temperature, with decreasing dependent increasing temperature. ❖The fuel consumption may increase by as much as 15 %.
  12. 12. Selecting right viscosity- Rating of Lubricating Oil engines use high viscosity grades oil. 12 ❖ Lubricatin g oil i s generally rated using a viscosity scale established by the SAE .Commonly used viscosity grades are: SAE 5 SAE 10 SAE 20 SAE 30 SAE 40 SAE 45 SAE 50 ❖The oil with lower viscosity grades is less viscous and is used in cold-weather operation. Modern high temperature, high speed, close tolerance
  13. 13. 13 RATING OF LUBRICATING OIL – VISCOSITY INDEX ❖When certain polymers are added to oil, the temperature dependency of oil viscosity is reduced. These oils have low viscosity grades when they are cold and higher as they become hot. ❖As for example, SAE 10W-30 means that the oil has a grade 10 when it is cold (W stands for winter) and 30 when it is hot. ❖Commonly used oils in this category are: SAE 5W-20 SAE 10W-40 SAE 5W-30 SAE 10W-50 SAE 5W-40 SAE 15W-40 SAE 5W-50 SAE 15W-50 SAE 10W-30 SAE 20W-50
  14. 14. Rating of Lubricating Oil (b)Specific Gravity: This property is of little importance except as an indicator of weight and volume. The specific gravity of oil varies from 0.85 to 0.96. (c)Pour Point: It indicates the temperature below which the lubricating oil loses its fluidity and will not flow or circulate in the system. This characteristics of the oil is important at low temperature. 14
  15. 15. Rating of Lubricating Oil (d) Oxidation Stability: Oxidation stability of an oil is its resistance to oxidation. Due to oxidation, oil forms deposits on the piston rings, and thereby loses its lubricating property. Some inhibitors are used to counteract these tendencies. (e) Acidity and Neutralization lubricating oil should have low Number: Th e acidity. The neutralization number is a measure of acidic or alkaline contents of oil.(TAN Number) (f) Oiliness: Oiliness is responsible for the boundary layer of molecules that can adhere or cling to a metal surface and provide lubrication after most of the oil gets displaced or squeezed out. 15
  16. 16. CLASSIFICATION OF LUBRICANTS 16 • Animal • Vegetable • Mineral • Synthetic
  17. 17. Types of Lubricating Oil Q Vegetable oils have been used in the past, especially for racing car engines. The main advantages of these oils are their high film strength, and they have a good lubricity. 17 Q Later, specially formulated have replaced their use mineral in oil s highperformance engines. Mineral oils are most readily available and cost effective. They readily respond to additives, and can be produced in a wide range of viscosities. The main disadvantage lies with its wax content that affects cold performance and can clog filters.
  18. 18. ANIMAL LUBRICANTS 18 • Lubricants with animal origin: – Tallow – Tallow oil – Lard oil – Neat’s foot oil – Porpoise oil • These are highly stable at normal temperatures • Animal lubricant s may not be used fo r internal combustion because they produce fatty acids.
  19. 19. VEGETABLE LUBRICANTS 19 of mineral• There are three classifications lubricants: – Solid, Semisolid, Fluid • Examples of vegetable lubricants are: – Castor oil, Olive oil, Cottonseed oil • Animal and vegetable oils have a lower coefficient of friction than most mineral oils but they rapidly wear away steel. Mineral Lubricants • These lubricants are used to a large extent in the lubrication of aircraft internal combustion engines.
  20. 20. SYNTHETIC LUBRICANTS 20 • Because of the high operating temperatures of gas-turbine engines, it became necessary to develop lubricants which would retain theircharacteristics at temperatures that cause petroleum lubricants to evaporate and break down. • Synthetic lubricants do not break down easily and do not produce coke or other deposits.
  21. 21. Additives ❖ Corrosion and Rust Inhibitors ❖ Anti-foam Agents ❖ Detergent-Dispersants ❖ Pour Point Improvers ❖ Oiliness and Film-strength Agents 21
  22. 22. Conclusions In order to minimize friction between the moving parts and hence wear, lubrication system in an engine plays a significant role. The lubrication system is designed to deliver clean oil at the correct temperature and pressure to every part of 22 the engine. Lubricatin g oil can be supplied to the various engine components by a splash system or by a pressurized system or a by a combination of both. In two-stroke engines, oil is mixed with the fuel itself.