2. Effects of Improper and Insufficient
Lubrication
• Carelessness of the operator – time
• Poor construction of bearings – lack of maintenance
• Failure to provide adequate means of conducting
lubricants to the bearings - level
Therefore, lubrication is needed because of friction.
3. Friction
• Force that acts between two bodies at their surface of
contact to resist the sliding of one body on the other.
Friction
4. Rolling Friction
• When one body rolls upon another, the friction is
much less than when one body slides upon another.
The resistance is called rolling friction
Friction Roller
5. Anti friction bearing
• In the form of balls or rollers to diminish the amount
of friction. Therefore increase the efficiency of
machine
6.
7.
8. The Present Condition of Friction
• Loss of horsepower – decrease 18%
• Graduated loss of fuel economy
• Frequent oil drains due to degradation
• Component wear
• Increased emissions
• Rising maintenance cost
• Rising labor cost
9. 5 Functions of the Lubricant
1) Friction reduction
2) Seal the cylinders
3) Heat removal
4) Cleanse
5) Absorb shock
10. Purpose of Lubrication
• Helps the engine to run smoothly and last longer
• Absorbs and dissipates heat
• Helps in the cooling system
• Prolongs engine life
11. 3 basic types of engine lubricating system
a. Circulating Splash
b. Internal Force Feed and Splash
c. Full Internal Force Feed
12. a) Circulating Splash System
Used in small single cylinder air cooled engine
A pump supplies oil to a splash pan under the crankshaft
As the connecting rod revolve, scoops on the end of rods
dip into trough and oil is gravity fed through channels or
lines
The upper parts of cylinders, pistons and pins are lubricated
more by oil mist taken by the oil splash. The mist is created
by the rapid movement of the connecting rods
13.
14. b) Internal Force Feed and Splash
– A pump forces oil directly to a main oil gallery in
the engine block rather than to a splash pan
– From main oil gallery, the oil is force through
passages to the main bearings, camshaft bearings,
rocker arm shaft, filter and pressure sending unit
– The oil escaping from the bearings creates a mist
that also lubricates the upper cylinder walls,
pistons and pins
15. c) Full Internal Force Feed System
• Preferred in all modern diesel and petrol engines
• Pump usually in the form of gear pump
– Oil is force not only to the crankshaft
– bearings, rocker arm shaft, filter and pressure-sending unit,
but also to the piston-pin bearing
– Piston pin bearing are lubricated through drilled passages
in the connecting rods. The cylinder walls and pistons are
lubricated by
i) oil escaping from piston-pin bearing
ii) or the connecting rod bearings
iii) or by oil sprayed by the underside of piston and cylinder wall
16.
17.
18. How Full Force Feed System Work
Oil pump pushes oil through the system
A reserve of oil is stored in the crankcase for circulation
through the system
At the oil filter, dirt is taken out of the oil to help it keep clean
Oil passages take the oil to engine parts where they provide
lubrication and cooling and carry away dirt and deposits
Pressure of the oil is regulated by pressure regulating valve
After oil moves through the whole system it comes back to
the crankcase reservoir again
Pressure gauge tells the operator if engine oil is normal
19.
20. Major Parts of Lubrication System
1. Oil pump
2. Crankcase
3. Oil cooler (if any)
4. Oil filter
5. Pressure regulating valve
6. Pressure gauge
21.
22. Criteria of Lubrication
1. Keep a protective oil film on moving parts
2. Resist high temperatures
3. Resist corrosion and rusting
4. Prevent ring sticking
5. Prevent sludge formation
6. Flow easily at low temperature
7. Resist foaming
8. Resist break down after prolong use
23. Petrol Lubrication
• Is common to small two stroke engines, consist of
mixing a small quantity of oil with the petrol
• Ratio of oil to petrol vary from 16 parts petrol to 1
part of oil for larger engine to 24:1 for smaller two
stroke engines
24. Maintenance
1. Changing Engine Oil
prolong using the oil will make the oil dirty and its
additives wear out:-
• acid formations
• sludge
• varnish
• engine deposits
• contaminated oil will make it unfit for continued use
that will harm the vital engine parts
25. 2. Follow the manufacturer’s recommendation on oil and filter
changes
e.g. 50 hours of working
3. When changing oil and filter on any engine, always warm up
the engine first. This way the contaminants and foreign
materials are mixed with the oil and drained out with it
4. After installing the filter and filling the engine with oil, run
the engine and check for possible filter leaks
5. Keep a maintenance record of all oil and filter changes to be
sure of regular engine service
26. Classification of Oil
• Lubrication oil are classified according to their viscosity
“thickness” and are given a number which tell us the grade of
oil and in some cases the type
• Classification is by the Society of Automotive Engineers
(SAE)
Engine oils are given this number SAE 10; 20; 30; 40
Gear & transmission oil are given this number SAE 50; 70; 90
Power system oil SAE 120; 140
27. • The lower number indicate low viscosity oil suited to
cold climates or engines with many stop and start
continually, therefore never reaching proper working
temperature.
• The higher numbers indicate high viscosity more
suited to hot climates, or engines continually running
in hot conditions.
28. Detergent Oil
• Oil that contains additives which prevent the
formation of carbon and lacquer inside an engine.
• Used for lubrication of a diesel engine because when
diesel fuel burns in the combustion chamber it
produce sediments which stick to the working parts of
the engine.
• This sediments collect on piston, piston rings and
cylinder walls resulting in increased wear.
• The additives prevent this from happening by holding
in suspension the sticky particles which would settle
on the piston.
29. Multigrade Oil
• Oil have special additives which reverse the normal
tendency of an oil to thicken when cold and thin out
when hot .
• They are numbered SAE 10-30 or 20-50 and are
called viscostatic or Universal Engine Oil more suited
to petrol or propane engines.
30. Universal Oil
• These oil are produced to reduce the number of
different types of oil needed to serve all types of
tractor and implements, covering engines,
transmission, hydraulic system, power steering, etc.
• These oil are of a multigrade in nature with suitable
additives to combat engine contaminants, gearbox
stresses, anti frothing for hydraulic system and power
steering
