2. Purpose of Lubrication System
•Lubricate
Reduces Friction by
creating a thin
film(Clearance)
between moving
parts
•Seals
The oil helps form a seal
between piston rings and
cylinder walls (Reduces
Blow-By)
Internal oil leak (blow-
by) will
result in BLUE SMOKE
at the
tail pipe.
3. Purpose of Lubrication System
•Cleans
As it circulates through the engine, the oil picks up metal
particles and carbon, and brings them back down to the pan.
•Cools
Picks up heat when moving
through the engine and then
drops into the cooler oil pan,
giving up some of this heat.
4. Purpose of Lubrication System
•Absorbs shock
When heavy loads are imposed on the bearings, the oil
helps to cushion the load.
•Absorbs Contaminants
The additives in oil helps in absorbing the contaminants
that enter the lubrication system.
5. Lubrication System Types
• Petroil or mist lubrication (Petrol and Oil Premix)
• Autolube
• Splash
• Pressure Fed or Force Feed
– Wet Sump
– Dry Sump
6. Used where crankcase lubrication is not suitable.
(In two stroke engine, as the charge is
compressed in the crankcase, it is not possible to
have the lubrication oil in the sump. Hence mist
lubrication is used in practice).
Mist lubrication system
7. The lubrication oil is mixed with the fuel, the usual ratio
being 2% to 5%.
Oil and fuel mixture is inducted through the carburetor.
Fuel is vaporized and the oil in the form of mist goes via
the crankcase into the cylinder.
The oil which strikes the crankcase walls lubricates the
main and connecting rod bearings and the rest of oil
lubricate the piston, piston rings and the cylinder.
Mist lubrication system
9. Disadvantages
•Cause heavy exhaust smoke due to burning of lubricating
oil
•Forms deposit on piston crown and exhaust port which
affect engine efficiency.
•Requires a thorough mixing for effective lubrication. This
requires either separate mixing prior to use or use of some
additive to give the oil good mixing characteristics.
•During closed throttle operation (as in the case of vehicle
moving down the hill), the engine suffers from insufficient
lubrication as the supply of fuel is less. This is an important
limitation of system
10. Autolube System
•Used in 2 stroke engines
•Oil is stored in a separate tank
•A nozzle sprays measured quantity of oil in the crankcase
in every stroke
•More efficient than mist lubrication system
•Used in Kinetic Honda, Yamaha RX 100
11. Splash System
•Used in light duty, slow speed engines (<250 rpm).
•Lubricating oil is stored at the bottom of engine crankcase and
maintained at a predetermined level.
•The oil is drawn by the pump and delivered through a distributing
pipe into the splash trough located under the big end of all the
connecting rods.
•These troughs are provided with overflows and oil in the trough is
therefore kept at a constant level.
•A splasher or dipper is provided under each connecting rod cap
which dips into the oil in the trough at every revolution of the
crankshaft and the oil is splashed all over the interior of crankcase,
into the pistons and onto the exposed portion of cylinder walls.
•The oil dripping from the cylinder is collected in the sump where it
is cooled by the air flowing around. The cooled oil is then
recirculated
13. Pressure Feed System
Oil is drawn from the sump by an oil pump through an oil strainer.
The strainer is a fine mesh screen which prevents foreign particles
from entering the oil circulating system.
A pressure relief valve is provided which automatically keep the
delivery pressure constant and can b set to any value. When the oil
pressure exceed that for which the valve is set, the valve open and
allow some of the oil to return to the sump thereby reliving the oil
pressure in the system.
16. Lubrication System – Wet Sump
Oil is stored in the sump.
Drawn into engine through
the pickup.
Forced round by a pump.
Protected by a pressure
relief valve.
Carried around
in galleries.
Particulates removed
by a filter.
18. Dry Sump
It is used in situations
when a wet sump
cannot cope with the
oil supply, in unusual
or extreme
conditions; Heavy
acceleration (racing
cars), Off road driving,
steep hills and uneven
surfaces
It uses an additional pump as well as a remote oil tank
23. Oil sump
• Made of Sheet Metal with baffle plates inside
• Storage reservoir for oil (Holds 3 to 6 liters)
• Plug on bottom to drain.
24. Oil Pump
Driven by camshaft, crankshaft
All types of oil pumps use a pick-up
screen in the sump and a pressure
regulator.
•Rotor Pump(Two star
shaped rotors pump the
oil)
•Gear Pump
25. Rotary Oil Pump
May be shaft, gear or chain driven.
Inner rotor driven by pump shaft.
Inner rotor drives outer rotor.
Oil is forced from input to output
26. Crankshaft-Driven Pump
Drive splines
on crankshaft.
Outer gear (rotor)
driven by inner gear.
Inner gear (rotor)
driven by crankshaft.
Pump housing at
front of engine.
Pump insert holds
drive within housing.
Main seal.
27. Gear Pump
Pump shaft drives one gear.
Other gear rotates.
Low pressure at input.
High pressure at output.
28. Oil Filters
• Micro-porous paper filters used to screen out particles.
• Most filters are of the cartridge type.
• Remove harmful materials
• Two Types
– Full Flow
– Bypass
29. Bypass Systems
• Part of oil goes from
sump to filter
• Part goes to engine
for lubrication
• Over time, entire oil
is filtered
• Very fine filter is
used
30. Full Flow Systems
• All the oil goes to the
system through filter
• Relatively a coarse filter
is used
• Relief valve is used to
ensure oil supply to
engine in case of filter
clogging
31. Oil Level and Pressure Indicators
• Dipstick the most
simple
• Some engines
equipped with an
electrical level
indicator.
• Oil pressure
indicator lamp
• Oil pressure gauge
(electrical or
mechanical)
32. Oil Pressure Indicator
• Light or a Gauge
• The light turns on or gauge reads low when pressure
drops below specified value (10psi or .7kg/sqcm)
• Correct oil pressure is 40-60 psi
Common causes of low oil pressure are:
•Low oil level
•Worn out pump
33. Oil Filter
Keeps impurities out of the engine.
Spin-on oil filter with O-ring seal.
Centre outlet tube.
Paper elements trap impurities.
Input feed holes.
35. Pressure Relief Valve
• Fitted between the pump and the filter
• Used to prevent damage to the engine due to
too much oil pressure.
36. Oil Pressure sending unit
Electrically sends the signal to the Light or Gauge mounted
on the dash.
If the wires get short the light will come on or the gauge will
read high (Full Scale)
38. Oil Contamination
• Blow-by gases add raw petrol and water to the oil
causing deterioration.
• Excessive heat can cause thermal breakdown.
• Excessive cranking can dilute oil with petrol.
• Cooling gasket leaks will ruin oil causing sludge.
• Short distance driving. (which is most trips)
• Extensive idling.
• Cold weather operation.
• Trailer towing.
• Excessive heavy loads
• Dirty and dusty conditions.
