Engine Lubrication System | Working Principle , Types and Components | Learn Mechanical Engineering (2023)

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When two metallic surfaces under direct contact move over each other, they create friction which generates heat. This causes excessive wear and tear of those moving parts. However, when a film of lubricating matter separates them from each other, they do not come in physical contact with each other. Thus, lubrication is a process that separates the moving parts by supplying a flow of a lubricating substance between them. The lubricant could be liquid, gas or solid. However, engine lubrication system mainly uses liquid lubricants.

Read more :
Lubrication system used for IC engines
What is Lubrication System | Function of lubrication
Importance of Lubrication and Cooling Systems in an Engine


The engine lubrication system is to distribute oil to the moving parts to reduce friction between surfaces. Lubrication plays a key role in the life expectancy of an automotive engine . If the lubricating system fail, an engine would succumb to overheating and seizing very quickly. An oil pump is located on the bottom of the engine. The oil is pulled through a strainer, by the oil pump, removing larger contaminants from the mass of the fluid.

Engine Lubrication System | Working Principle , Types and Components | Learn Mechanical Engineering (4)

The oil then forced through an oil filter under pressure to the main bearings and the oil pressure gauge. It is important to note that not all filters perform the same. A filter’s ability to remove particles is dependent upon many factors, including the media material (pore size, surface area and depth of filter), the differential pressure across the media, and the flow rate across the media. From the main bearings, the oil passes into drilled passages in the crankshaft and the big-end bearings of the connecting rod.

The oil fling dispersed by the rotating crankshaft lubricates the cylinder walls and piston-pin bearings. The excess oil is scraped off by the scraper rings on the piston. The engine oil also lubricates camshaft bearings and the timing chain or gears on the camshaft drive. The excess oil in the system then drains back to the sump.


1. Minimizes power loss by reducing the friction between the moving parts.
2. Reduces the wear and tear of the moving parts.
3. Provides cooling effect to the hot engine parts.
4. Provides cushioning effect against vibrations caused by the engine.
5. Carries out the internal cleaning of the engine.
6. Helps piston rings to seal against high-pressure gases in the cylinder.

Engine lubrication system supplies the engine oil to the following parts:

1. Crankshaft main bearings
2. Big end bearings
3. Piston pins and small end bushes
4. Cylinder walls
5. Piston rings
6. Timing Gears
7. Camshaft and bearings
8. Valves
9. Tappets and push-rods
10. Oil pump parts
11. Water pump bearings
12. In-Line Fuel Injection Pump bearings
13. Turbocharger bearings (if fitted)
14. Vacuum pump bearings (if fitted)
15. Air-compressor piston and bearings (in commercial vehicles for air-brake)

(Video) Engine lubrication system / How does it work? (3D animation)


There are mainly four types of lubrication systems used in automotive engines which are:
1. Petroil System
2. Splash System
3. Pressure system
4. Dry-Sump System


1. Oil Sump
2. Engine oil filter
3. Piston cooling nozzles
4. Oil Pump
5. The Oil Galleries
6. Oil Cooler
7. The Oil pressure indicator/light

Oil Pan / Sump:

An Oil Pan / Sump is just a bowl-shaped reservoir. It stores the engine oil and then circulates it within the engine. Oil sump sits below the crankcase and stores the engine oil when the engine is not running. It is located at the bottom of the engine in order to collect and store the engine oil. The oil returns to the sump by pressure/gravity when the engine is not in use.

Bad road conditions could cause damage to the Oil Pan / Sump. So, the manufacturers provide a stone guard/sump guard underneath the sump. The sump guard absorbs the hit from the uneven road and protects the sump from any damage.

Oil Pump:

An Oil Pump is a device which helps to circulate the lubricant oil to all the moving parts inside the engine. These parts include crankshaft & camshaft bearings as well as valve lifters. It is generally located at the bottom of the crankcase, close to the oil sump. The oil pump supplies the oil to oil filter which filters and sends it onward. The oil then reaches different moving parts of the engine through oil galleries.

Even, small particles can choke the oil pump and galleries. If oil Pump gets blocked, then it can cause the severe damage to the engine or even complete seizure of the engine. To avoid it, the oil pump consists of a strainer and a by-pass valve. Hence, it is necessary to change the engine oil and filter at regular intervals as recommended by the manufacturers.

Oil Galleries:

In order to get better performance and longer engine life, it is essential that the engine oil quickly reaches the moving parts of the engine. For this purpose, manufacturers provide oil galleries within the engine. The Oil Galleries are nothing but series of interconnected passages which supply the oil to the remotest parts of the engine.

(Video) Lubrication System in Engine || Engine Lubrication System

Oil galleries consist of big and small passages drilled inside the cylinder block. The bigger passages connect to the smaller passages and supply the engine oil upto the cylinder head and overhead camshafts. The oil galleries also supply the oil to the crankshaft, crankshaft bearings and camshaft bearings thru holes drilled in them as well as to valve lifters/tappets.

Oil Cooler:

The Oil Cooler is a device which works just like a radiator. It cools down the engine oil which becomes very hot. Oil cooler transfers the heat from the engine oil to the engine coolant through its fins. Initially, manufacturers used the oil cooler only in the racing/high-performance vehicles. However today, most vehicles use oil cooler system for better engine performance.

Oil cooler which helps to maintain the engine oil temperature also keeps its viscosity under control. Additionally, It retains the lubricant quality, prevents the engine from overheating and thereby saving it from wear and tear.

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Sachin Thorat

Sachin is a B-TECH graduate in Mechanical Engineering from a reputed Engineering college. Currently, he is working in the sheet metal industry as a designer. Additionally, he has interested in Product Design, Animation, and Project design. He also likes to write articles related to the mechanical engineering field and tries to motivate other mechanical engineering students by his innovative project ideas, design, models and videos.

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What are the principles of engine lubrication? ›

In theory, fluid lubrication is based on the actual separation of the surfaces so that no metal-to-metal contact occurs. As long as the oil film remains unbroken, metallic friction is replaced by the internal fluid friction of the lubricant. Under ideal conditions, friction and wear are held to a minimum.

What are the 6 components of engine lubrication system? ›

Components of engine lubrication system
  • Oil sump.
  • Engine oil filter.
  • Piston cooling nozzles.
  • Oil pump.
  • The oil galleries.
  • Oil cooler.
  • The oil pressure indicator/light.
Oct 27, 2019

What are the components of the engine lubrication system? ›

A typical engine lubrication system involves components like Oil – sump, strainer, pump and filter, all of which are parts of the initial oil suction line. In addition, the main gallery involves components like flow passages within the connecting rods, crankshaft, and bearings.

What are the 5 components of the lubrication system? ›

The components of industrial lubrication systems are the reservoir, lubrication pump, metering device, controller, filter, supply lines, and feed lines.

What are the 5 types of lubricants? ›

What Are the Different Types of Lubricants?
  • Oil-based lubricants. Oil-based lubricants are used for a wide range of applications, helping to minimise friction between moving parts and maintain mechanical efficiency. ...
  • Grease-based lubricants. ...
  • Penetrating lubricants. ...
  • Dry lubricants.
Feb 16, 2022

What are the 4 principles of engine? ›

In the four-stroke cycle gasoline engine, there are four strokes of the piston in each cycle: two up and two down. The four strokes of a cycle are intake, compression, power, and exhaust. A cycle occurs during two revolutions of the crankshaft.

What are the four working principles of an engine? ›

Working Principle of a Four-Stroke Engine

The working of four-stroke engine consists of four strokes – Suction, Compression, Power, and Exhaust.

What is lubrication in mechanical engineering? ›

Lubrication is the control of friction and wear by the introduction of a friction-reducing film between moving surfaces in contact. The lubricant used can be a fluid, solid, or plastic substance.

What are the 7 purposes of lubrication? ›

To lubricate each part of the bearing, and to reduce friction and wear. To carry away heat generated inside bearing due to friction and other causes. To cover rolling contact surface with the proper oil film in order to prolong bearing fatigue life. To prevent corrosion and contamination by dirt.

What are the 3 types of oil pumps? ›

Oil Pumps can be used for a wide variety of oil applications, varying in viscosities. Some of the most common pump types used are centrifugal pumps, peristaltic pumps, gear pumps and progressive cavity pumps.

What are the three functions of engine lubrication? ›

Lubricants provide three major functions within your engine: cooling, cleaning and reducing friction. The goal is to protect the engine components against damage from heat, contaminants and metal-to-metal contact. But how exactly does the engine oil accomplish these things?

What are seven components of the engine lubrication system? ›

What are the components of a lubrication system? Oil pan, pickup tube, oil pump, pressure relief valve, oil filter, spurt holes and galleries, and sump.

What are the types of lubricants? ›

There are 4 types of lubricants: Oil, Grease, Penetrating Lubricants, and Dry Lubricants.

What are the six main functions of the lubrication system? ›

There are 6 Basic Functions of a Lubricant/Oil.
  • Lubrication – Provide a film between moving parts.
  • Cooling – Heat transfer media.
  • Sealing – Filling in uneven surfaces.
  • Cleaning – Holding contaminants in suspension.
  • Dampening & Cushioning – Of components under high stress.
  • Protection – From oxidation & corrosion.
Sep 16, 2022

What are the two types of lubrication? ›

Understanding the three types of lubrication
  • Full film lubrication. Hydrodynamic and elastohydrodynamic are the two forms of full film lubrication. ...
  • Boundary lubrication. ...
  • Mixed lubrication.
Nov 23, 2020

How many types of engine oil are there? ›

Motor oil can be segmented into four basic varieties—synthetic oil, synthetic blends, high mileage oil, and conventional oil.

What are the 3 systems of an engine? ›

There are three major engine systems necessary to keep an internal combustion engine running. They are the ignition system, the lubrication system, and the fuel system.

What are the 8 main engine systems? ›

Engine Systems
  • Starting System.
  • Fuel System.
  • Ignition System.
  • Cooling System.
  • Lubrication System.
  • Intake System.
  • Exhaust system.
  • Charging System.
May 7, 2011

What are the 4 most common types of engine design? ›

The most common engine types - the four-cylinder, the boxer-four, straight-six, V6 and V8 - have their own pros and cons.

What are the principles of piston engine? ›

Piston: The piston of an engine is the first part to begin movement and to transmit power to the crankshaft as a result of the pressure and energy generated by the combustion of the fuel. The piston is closed at one end and open on the other end to permit direct attachment of the connecting rod and its free action.

How does lubrication work? ›

Lubricants form an oil film on the surface of metals to reduce friction. Reduced friction prevents heating and abrasion on the friction surface. Lubricants maintain internal cleanliness by suspending contaminants within the fluid or by preventing the contaminants from adhering to components.

What is the system of lubrication? ›

A Lubrication system is a means whereby a material is placed between two rubbing surfaces to alleviate friction and therefore wear. For example if you rub your hands together they will heat up due to the friction and eventually your skin will burn.

What is lubrication engine? ›

Lubrication is the action of applying a substance such as oil or grease to an engine or component so as to minimize friction and allow smooth movement. Lubrication System. Lubricating system is a mechanical system of lubricating internal combustion engines in which a pump forces oil into the engine bearings.

What are the 2 basic types of pumps? ›

Main Types of Pumps: Centrifugal and Positive Displacement.

How are pistons lubricated? ›

The cylinder walls and piston-pin bearings are lubricated by oil fling dispersed by the rotating crankshaft. The excess being scraped off by the lower ring in the piston. A bleed or tributary from the main supply passage feeds each camshaft bearing.

What causes oil pump failure? ›

What causes car oil pump failure? Engine sludge, which is usually a combination of dirt, contamination and old engine oil is highly damaging to a car's mechanical parts, restricting normal oil flow and causing friction and heat build-up, both of which can lead to oil pump failure.

What are the 10 automotive systems? ›

Vehicle Systems Overview
  • Batteries.
  • Belts & Hoses.
  • Brake System.
  • Emission System.
  • Engine Cooling.
  • Exhaust System.
  • Filters & Fluids.
  • Fuel System.

What are the 2 types of lubrication systems for 4 cycle engines? ›

Four-stroke engines are lubricated by oil held in an oil sump. The oil is distributed through the engine by splash lubrication or a pressurized lubrication pump system; these systems may be used alone or together. Splash lubrication is achieved by partly submerging the crankshaft in the oil sump.

What are the two main lubricants used in most motor vehicles? ›

We usually use conventional oil (also known as mineral oil) or synthetic oil for lubrication. Both these oils contain a base oil — generally of crude oil base stock — and additives.

What is the most important part of lubrication system? ›

Oil Pump: The oil pump is a component that helps to push the lubricating oil to all the moving parts in the engine. It's located at the bottom of the crankcase, close to the oil sump. It supplies oil to the oil filter before sending it further.

What are the major lubricant types? ›

There are 4 types of lubricants: Oil, Grease, Penetrating Lubricants, and Dry Lubricants.

What type of lubrication system is most commonly used? ›

In most automobiles, which lubrication system is commonly used? Explanation: Pressure type lubrication is used commonly in most automobiles. In this system, oil is drawn in from the sump and forced to all the main bearings of the crankshaft through distributing channels.

What are the three methods of lubrication? ›

There are three methods of lubricating LM systems: manual greasing using a grease gun or manual pump, forced greasing with the aid of an automatic pump, and oil-bath lubrication.


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