LUBRICATION SYSTEM
UNIT-4 LUBRICATION SYSTEM
EME-505
B.TECH 5TH SEM MECHANICAL ENGINEERING
2013 batch
BY
VINOD KUMAR YADAV
(ASSISTANT PROFESSOR)
MECHANICAL ENGG. DEPTT
G.L.B.I.T.M GREATER NOIDA

LUBRICATION SYSTEM

Purpose of Lubrication System
1. Lubricate
Reduces Friction by creating a thin film(Clearance)
between moving parts (Bearings and journals)

Purpose of Lubrication System
2. Seals
The oil helps form a gastight
seal between piston rings
and cylinder walls
(Reduces Blow-By)
Internal oil leak (blow-by) will
result in BLUE SMOKE at the
tale pipe.

Purpose of Lubrication System
3. Cleans
As it circulates through the engine, the oil picks up metal
particles and carbon, and brings them back down to the pan.

Purpose of Lubrication System
4. Cools
Picks up heat when moving through the engine and then
drops into the cooler oil pan, giving up some of this heat.

Purpose of Lubrication System
5. Absorbs shock
When heavy loads are imposed on the bearings, the oil helps to cushion the
load.
6. Absorbs Contaminants
The additives in oil helps in absorbing the contaminants that enter the
lubrication system.

VISCOSITY
Viscosity is a measure of oil’s resistance to flow.
•A low viscosity oil is thin and flows easily
•A high viscosity oil is thick and flows slowly.
•As oil heats up it becomes less viscous
(Becomes thin)

VISCOSITY
•If the oil is too thin(has very low viscosity) it will be forced
out from between the moving parts, resulting in rapid wear.
•If the oil is too thick(has very high viscosity) it will flow very
slowly to engine parts, especially when the engine and the oil
are cold, resulting in rapid wear.
Viscosity Index is the measure of how much the viscosity of
an oil changes with temperature. (20 W)
Viscosity number is set by SAE (Society of Automotive
Engineers)

VISCOSITY
• There are two temperatures used as reference in assigning the numbers to
oils -18oC (0oF) and 99oC (210oF)
•Single viscosity oils SAE 5W, SAE 10W and SAE 20W (Winter) Are defined
in terms of viscosity at -18oC and are oils which render starting in cold
climates easy
•SAE 20, SAE30, 40, and 50 grades Are defined
in terms of viscosity at 99oC and are oils which works satisfactorily in normal
and hot climates
•Multiple viscosity oils SAE 10W-30.
This means that the oil is same as SAE 10W when cold
and SAE30 when hot.
Plz Note: MARUTI ALTO ENGINE OIL SF (PETROL) SAE 20 W 40
GEAR OILAPI GL- 4

VISCOSITY

Properties of oil
•Corrosion and Rust Inhibitor: Displaces water from
metal surfaces, to prevent corrosion.
•Foaming Resistance: Rotating crankshaft tends to cause bubbles (Foam) in
the oil and bubbles in oil will reduce the effectiveness of oil to lubricate.
•Synthetic Oils: Made by chemical process and do not necessarily come
from petroleum.

Components of lubrication system
Oil Pumps Driven by camshaft, crankshaft (Rarely rebuild by an auto
technician)
•Rotor Pump(Two star shaped rotors
pumps the oil)
•Gear oil Pump

Oil Pan
Stores the oil and helps in cooling the oil
Pan gasket splits if over tightened.
Components of lubrication system

Pressure Relief Valve to prevent the buildup of high
Pressure (Causes the oil filter to bulge, but not a common
problem).
Good oil pressure is
40-60 psi
Components of lubrication system

Oil Pressure Indicator
•Light or a Gauge
The light turns on or gauge reads low when
the pressure drops below 10psi.
Common causes of low oil pressure are:
•Low oil level
•Worn out pump
Low oil pressure Safety system will shuts down the car by
cutting the ignition System(Spark).
•Good oil pressure is 40-60 psi.
Components of lubrication system

Oil Filter filters the oil
Some particles are too small for the filter Element(paper
in the filter ) to trap.
Components of lubrication system

Oil Galleries
Deliver the oil to top
end and returning it
To the oil pan.
Components of lubrication system

•Pollution prevention
•Blow-by back into the intake
•Prevent sludge in the engine.
Positive Crankcase ventilation (PCV) Valve
PCV recycles the blow by gases to the intake manifold from where they are
pumped back for next combustion cycle.
Not always desirable as it may dilute the A/F mixture ( makes too lean)
So blow by gases are recycled when the car is travelling at low speeds or idling
When car is idling – air pressure in the inlet manifold is lower than the air
pressure in the crankcase, so it sucks the blow bye gases through the PCV
and backs into the inlet manifold

Positive Crankcase ventilation (PCV) Valve

SO finally
We have come to know the importance of Lubrication
system
• LUBRICATING
• COOLING
• CLEANING
• SEALING
• NOISE REDUCTION
CLASSIFICATION OF LUBRICATING SYSTEM
1- WET SUMP LUBRICATION SYSTEM
(i) splash lubrication
(ii) Pressurized lubrication system
2- DRY SUMP LUBRICATION SYSTEM
3- MIST LUBRICATION SYSTEM

1-WET SUMP LUBRICATION
Sump always filled with lubricating oil

WET SUMP LUBRICATION SYSTEM
1-(a) SPLASH SYSTEM
Used in small and medium vehicles and four stroke stationary
engines with moderate and low bearing load pressures
Connecting rod Big end caps – provided with scoops – dip into the oil troughs
-Directs oil through holes in caps to big end bearings
-Due to splashing action – oil lubricates cylinder walls, crankshaft and other components
-Remaining oil return to oil sump
-Oil level in trough – maintained by pump via filter

Splash lubrication system

WET SUMP LUBRICATION SYSTEM
1(b) pressure lubrication system
OIL form the oil sump is pumped under pressure to the
various parts of the engine requiring lubrication .
The oil is drawn from the sump through the filter and
pumped by means of gear pump. Oil is delivered by
pressure pump at pressure ranging from 1.5 bar to 4 bar.
The oil under pressure is supplied to main bearings of
the crankshaft and camshaft. Holes drilled through the
main crankshaft bearing journals, communicate oil to the
big end bearing and also small end bearing through
holes drilled in the connecting rods.
A pressure regulator is provided in the delivery side of
the pump to prevent excessive pressure.

PRESSURIZED LUBRICATION SYSTEM

2-DRY SUMP LUBRICATION SYSTEM
• Sump does not contain oil and all the oil required for lubrication
remains in circulation only.
• High speed racing cars and military jeeps uses this type as oil in the
wet sump is subjected to large back and forth acceleration system.
• An auxiliary tank is used to supply the oil to the main bearings with
the help of pump.
• The oil is returned back to tray and then returned back to auxiliary
tank by scavenging pump, the capacity of which is always 20 to 30
% more than the pressure pump to avoid the flooding of the crank
case.
• If filter clogged, the pressure relief valve opens and permits oil to
flow by passing the filter and supply tank. the oil is then circulated to
the bearings from the supply tank

DRY SUMP LUBRICATION

3-MIST LUBRICATION SYSTEM
DO YOU REMEMBER THE OLDER 2-S ENGINES IN WHICH WE
FREQUENTLY ADD 2T OIL WHILE FUELING ????
Used for 2-s cycle crank charged engines
2 to 3 percent lube oil in fuel tank-
Oil and fuel mixture induced via carburetor
Fuel is vaporized and oil in the form of mist goes via crankcase into
cylinder
Some oil pass to the chamber during entry and scavenging and lubricate
piston ,piston rings and cylinder walls
Problem: oil burns with fuel and emit heavy exhaust and deposits on
piston crown, ring grooves and exhaust port
Corrosion damage of bearings
5 to 15 percent higher lubricant consumption

GRADES FOR OILS
Gear oil is a lubricant made specifically for transmissions, transfer cases, and
differentials in automobiles, trucks, and other machinery.
It is of a higher viscosity to better protect the gears and usually is associated
with a strong sulfur smell.
This is necessary since the devices needing this heavy oil do not have pumps for
transferring the oil with only a portion of the lowermost gears bathed in an oil
sump. This heavy oil can create viscous drag leading to inefficiencies in vehicle
operation.
Some modern automatic transaxles (integrated transmission and differential)
do not use a heavy oil at all but lubricate with the lower viscosity hydraulic
fluid, which is available at pressure within the automatic transmission.
Most lubricants for manual gearboxes and differentials are hypoid gear oils. These
contain EXTREME PRESSURE (EP) ADDITIVES and ANTIWEAR ADDITIVES to cope with
the sliding action of hypoid bevel gears.
It is extremely important to note that EP additives which contain
PHOSPHOROUS/SULFUROUS compounds are corrosive to yellow metals
such as the copper and/or brass used in bushings and synchronizers; the GL1
class of gear oils does not contain any EP additives and thus finds use in
applications which contain parts made of yellow metals.

GEAR OIL RATING
• Gear oils are classified by the AMERICAN PETROLEUM INSTITUTE
(API) using GL ratings.
• For example, most modern gearboxes require a GL-4 oil, and separate
differentials (where fitted) require a GL-5 oil.
• It is important that purchasers check the oil against the vehicle
manufacturer's specification to ensure it does not contain any aggressive
chemicals that may attack yellow metal gear components, such as phosphor
bronze.
• API viscosity ratings for gear oils are not directly comparable with those for
motor oil, and they are thinner than the figures suggest. For example, many
modern gearboxes use a 75 W 90 gear oil, which is actually of equivalent
viscosity to a 10 W 40 motor oil.

GEAR OIL RATING
• Multigrade gear oils are becoming more common; while gear oil does not
reach the temperatures of motor oil, it does warm up appreciably as the
car is driven, due mostly to shear friction
• API(AMERICAN PETROLEUM INSTITUTE) classification subdivides
all transmission oils into 6 classes:
• API GL-1. Oils for light conditions. They consist of base oils without
additives. Sometimes they contain small amounts of ant oxidizing
additives, corrosion inhibitors, depressants and antifoam additives. API
GL-1 oils are designed for spiral-bevel, worm gears and manual
transmissions without synchronizers in trucks and farming machines.
• API GL-2. Oils for moderate conditions. They contain anti-wear
additives and are designed for worm gears. Recommended for proper
lubrication of tractor and farming machine transmissions.
• API GL-3. Oils for moderate conditions. Contain up to 2.7% anti-wear
additives. Designed for lubricating bevel and other gears of truck
transmissions. Not recommended for hypoid gears.

GEAR OIL RATINGS
• API GL-4. Oils for various conditions - light to heavy.
They contain up to 4.0% effective anti-scuffing additives.
Designed for bevel and hypoid gears which have small
displacement of axes, the gearboxes of trucks, and axle
units.
• These oils are standard for synchronized gearboxes,
especially in Europe, and may also be recommended for
non-synchronized gearboxes of US trucks, tractors and
buses and for main and other gears of all vehicles. GL-4
oils may also be used in many limited-slip differentials.
• USED IN MARUTI ALTO (LXI) INDIA

GEAR OIL RATINGS
• API GL-5. Oils for severe conditions. They contain up to 6.5%
effective anti-scuffing additives. The general application of oils in this
class are for hypoid gears having significant displacement of axes,
generally non limited-slip differentials.
• GL-5 is not necessarily backward-compatible in synchro-mesh
transmissions which are designed for a GL-4 oil:
• GL-5 has a lower coefficient of friction due to the higher concentration
of EP additives over GL-4, and thus synchros can not engage as
effectively. Also, transmissions which explicitly call for GL-4 oil may
have been designed around this lower concentration of EP additives
and thus may contain yellow metal parts which GL-5 will corrode.
• They are recommended as universal oils to all other units of
mechanical transmission (except synchronized gearboxes specifying
GL-4). Some GL-5 oils in this class, which have special approval of
vehicle manufacturers, can be used in synchronized manual gearboxes.

GEAR OIL RATINGS
• API GL-6 is not applied any more as it is considered that class API
GL-5 well enough meets the most severe requirements. When API GL-
6 was still in use, it denoted oils for very heavy conditions (high speeds
of sliding and significant shock loadings).
• They contained up to 10% high performance anti-scuffing additives.
• They were designed for hypoid gears with significant displacement of
axes. However, in 2011 at least one company offers new polyol ester
based API GL-6 oil, mostly for racing applications.
• The application is limited to certain types of manual transmissions, but
improvements in BSFC of about 5% in standard weather and driving
conditions and up to 15-20% in cold extremes (arctic weather
conditions) can be expected.