The document discusses lubrication and cooling systems for internal combustion engines. It describes the purpose of lubrication systems as reducing friction, wear, and heat between moving engine parts. The main types of lubrication systems are wet sump and dry sump systems. It also discusses the necessity of cooling systems to dissipate heat from the engine and prevent overheating. The primary types of cooling systems are air cooling, which uses airflow over fins, and water cooling, which circulates water through a radiator to cool the engine.

1. LUBRICATION AND COOLING SYSTEMS

2. LUBRICATION SYSTEM OF IC ENGINES
 Lubrication is the process of applying the lubricant
between the surfaces of contact of two moving
parts.
 In an IC engine, parts moving rub each other
causing wear and tear and reduces the power
almost. so , lubrication is necessary for an IC
engine.

3. PURPOSE OF LUBRICATION
 To reduce the friction between moving parts
 To minimize the vibration .
 To reduce the wear and tear.
 To reduce the corrosion and carbon deposits.
 To reduce the heat of moving parts.
 To minimize the power lost due to friction.
 To reduce the noise created by the moving parts.

4. THE ENGINE PARTS THAT REQIRE
FREQUENT LUBRICATION ARE
 Cylinder piston and piston rings
 Main bearings
 Crankshaft
 Crank pin and piston pin
 Big end and small end connecting rod .
 cam shaft.
 Valves.

5. TYPES OF LUBRICATING SYSTEM
The lubrication system is classified into
1.Petroil lubrication is classified into
2.Wet sump lubrication.
3. Dry sump lubrication.

6. PETROIL (OR) MIST LUBRICATION
 This type of lubrication is used for two stroke cycle engines.
The lubrications oil (2 to 3 percent) is mixed with petrol in the
fuel tank. The oil and fuel mixture is inducted through the
carburettor. Petrol gets evaporated and the oil lubricates the
main parts of the cylinder.
 The fuel -oil ratio used is important for good performance. the
optimum fuel -oil ratio used is 50:1.
ADVANTAGE
 Separate lubricating system is not needed.
 No maintenance cost for lubrication system.
 Weight of engine is reduced by avoiding separate lubricating
system.
DISADVENTAGE
 If oil is less there is chance for seizure of engine.
 More oil makes excess smoke in the exhaust.

7. WET SUMP LUBRICATION
In this system a big oil sump is provided at the base
of crank case. From the sump the oil is pumped to
different parts of the engine. The main types of wet
sump lubrication system are
 splash lubrication system.
 Pressure lubrication system.
 semi pressure lubrication system.

8. SPLASH LUBRICATION SYSTEM
 The lubricating oil is stored in an oil through or sump.
A scoop or dipper is made in the lowest part of the
connecting rod. During every revolution of the
crankshaft, the dipper dips in the oil and splashes it.
Cylinder walls, piston rings, crankshaft bearings are
lubricated this way.

10. PRESSURE LUBRICATION SYSTEM
 In this system, the engine parts are lubricated
under pressure feed. The lubricating oil is stored in
the sump. An oil pump takes the oil through a
strainer and delivers it through a filter to the main oil
gallery at a pressure of 2-4 kg/cm.

12. SEMI-PRESSURE SYSTEM
 It is the combination of splash system and pressure
system. Some parts are lubricated by splash
system and some parts by pressure system. Almost
all four-stroke engines are lubricated by this
system.

13. DRY SUMP SYSTEM
 In this system, the oil is carried in a separate tank
from where it fed to the engine. pumped back to the
oil tank by a separate delivery pump. There are,
therefore, two pumps in this system- one to feed oil
and the other to deliver it back to the oil tank.

14. THE NECESSITY OF COOLING SYSTEM IN ENGINE
 All the heat produced by the combustion of fuel in
the engine cylinders is not converted into useful
power at the crankshaft. Only about 30% of the
heat is converted into mechanical work. About 40%
goes off through the exhaust. The remaining 30% is
useless to waste heat.
 It is seen that the quantity of heat given to the
cylinder walls is considerable and if this heat is not
removed from the cylinders, it would result in the
seizing of the piston, high fuel consumption, pre-
ignition and burning of lubricant etc.

15. TYPES OF COOLING SYSTEM IN ENGINE
Following are the two type of cooling system for
engine:
 Air cooling system
 Water cooling system

16. AIR COOLING SYSTEM
 Air cooled system is generally used in small
engines say up to 15-20 kW. The air system is used
in the engines of motorcycles, scooters, aero
planes and other stationary installations. In
countries with cold climate, this system is also used
in car engines.
 In this system, the heat is dissipated directly to the
atmospheric air by conduction through the cylinder
walls. In order to increase, the rate of cooling, the
outer surface area of the cylinder and cylinder head
is increased by providing radiating sins and flanges.
In bigger units, fans are providing to circulate the air
around the cylinder walls and cylinder head.

18. Advantages of Air Cooled System
(a) Radiator/pump is absent hence the system is light.
(b) In case of water cooling system there are
leakages, but in this case there are no leakages.
(c) Coolant and antifreeze solutions are not required.
(d) This system can be used in cold climates, where if
water is used it may freeze.
Disadvantages of Air Cooled System
(a) Comparatively it is less efficient.
(b) It is used in aero planes and motorcycle engines
where the engines are exposed to air directly.

19. WATER COOLING SYSTEM
 The water cooling system is used in the engines of cars,
buses, trucks, etc. In this system, the water is
circulated through water jackets around each of the
combustion chambers, cylinder, valve seats and valve
stems.
 The water is kept continuously in motion by a centrifugal
water pump which is driven by a V-belt from the pulley
on the engine crankshaft. After passing through the
engine jackets in the block and cylinder heads.
 The water is passing through the radiator. In the
radiator, the water is cooled by air drawn through the
radiator by a fan. Usually, the fan and water pump are
mounted and driven on a common shaft. After passing
through the radiator, the water is drained and delivered
to the water pump through a cylinder inlet passage. The
water again circulated through the engine jackets.

21. PARTS OF WATER COOLING SYSTEM
 Radiator.
 Thermostat valve.
 Water pump
 Fan.
 Water Jackets.
 Antifreeze mixtures.

22. TYPES OF WATER COOLING SYSTEM
There are two types of water cooling system :
Thermo Siphon System
 In this system the circulation of water is due to
difference in temperature (i.e. difference in
densities) of water. So in this system pump is not
required but water is circulated because of density
difference only.
Pump Circulation System
 In this system circulation of water is obtained by a
pump. This pump is driven by means of engine
output shaft through V-belts.

25. ADVANTAGES AND DISADVANTAGES OF WATER
COOLING SYSTEM
Advantages
 (a) Uniform cooling of cylinder, cylinder head and valves.
 (b) Specific fuel consumption of engine improves by using
water cooling system.
 (c) If we employ water cooling system, then engine need
not be provided at the front end of moving vehicle.
 (d) Engine is less noisy as compared with air cooled
engines, as it has water for damping noise.
Disadvantages
 (a) It depends upon the supply of water.
 (b) The water pump which circulates water absorbs
considerable power.
 (c) If the water cooling system fails then it will result in
severe damage of engine.
 (d) The water cooling system is costlier as it has more
number of parts. Also it requires more maintenance and
care for its parts.