This document discusses different types of engine lubrication systems. It describes wet sump lubrication systems, which use oil stored in a sump at the bottom of the engine that is pumped to parts. Within wet sump systems it describes splash, semi-pressure, and full-pressure lubrication. It also describes dry sump systems, which have an external oil tank instead of a sump. The key functions of lubrication systems are reducing friction and wear, minimizing power loss, cooling, cushioning shocks, cleaning, and sealing.
3. 3
ENGINE LUBEICATION
The lubrication is the flow of oil between two
mating surface having relatives motion.
Th effectiveness of lubrication plays an important
role in the performance characteristics and
determing the service life of an engine.
4. 4
TYPE OF ENGINE
LUBEICATION
1. Mist lubricatio
system
2. Wet sump
lubrictaio
a. Splash
Lubrication
b. Semi –
pressure
lubrication
c. Full Pressure
Lubrication
3. Dry sump
lubrication system
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Wet sump lubrication system
This system consists of a large storing capacity of
oil at base of the crank chamber. From the sump
the oil is drawn by the pump and applied to
various parts of the engine. Excess oil after
serving the purpose will gradually return to the
sump.
6. 6
Splash type lubrication
This type of lubrication is generally used in some small
four-stroke engines. In its construction a cap is present
on the big end of the connecting rod which consists of a
scoop. When the connecting rod is at the lowest position,
the scoop gets dipped into the oil, thus it directs the oil
into the holes present in the bearing. Due to the splash of
the scoop oil reaches the lower position of the cylinder
walls, crankshaft and other parts which requires
lubrication.
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Splash type lubrication
Oil level inside the pump is maintained a pump which
takes oil from the sump through a filter.
It is suitable for low and medium speed engines, which is
generally having moderate bearing load pressure. This
system does not serve properly for high speed engines,
which normally operates at high bearing pressure.
8. 8
FULL PRESSURE SYSTEM
In this system oil is pumped from oil sump and it
is distributed to various parts requiring lubrication.
The oil is drawn from the oil sump through a filter
and it is pumped by means of gear pump. Here
oil is delivered at a pressure of 1.5 bar to 4 bar.
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The oil with pressure is supplied to the main bearing in the crankshaft
and camshaft. Holes drilled through the main crankshafts bearing
journals, communicate oil to big end bearing and also small end
bearings through holes drilled in the connecting rods. Generally a
pressure gauge will be provided to confirm the circulation of oil to
various parts. On the delivery side a pressure regulation valve is
provided, to prevent the excessive pressure.
The general arrangement of wet sump lubrication system is shown in
the figure. In this case oil is always contained in the sump which is
drawn by the pump through a strainer.
FULL PRESSURE SYSTEM
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SEMI-PRESSURE SYSTEM
This method is a combination of both splash and pressure system. It
incorporates the advantage of both splash and pressure system. In this
system the main supply of oil is located in the base of the crank
chamber. Through a filter oil is drawn from the lower portion of the sump
and at a pressure of 1 bar it is delivered by means of a gear pump.
Through a nozzle spray the big bearing ends are lubricated. Thus oil
also lubricates the cam, crankshaft bearings, cylinder walls and timing
gears. With the help of oil pressure gauge the oil supply is controlled.
This system is less costly to install. It enables high bearing loads and
engine speed to be employed as compared to splash system.
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Purposes and Functions of
lubrication
1. It reduces friction between moving parts.
2. It reduces wear and tear of the moving parts.
3. It minimizes power loss due to friction.
4. It provides cooling effect – During circulation,
it carries heat from the hot moving parts and
delivers it to the surroundings through
crankcase.
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Purposes and Functions of
lubrication
5. It provides cushioning effect – It serves as a
cushion against the shocks of the engine.
6. It provides cleaning action – Impurities such
as carbon particles are dissolved during its
circulation.
7. It provides a sealing action – It helps the
piston rings to provide an effective seal against
high pressure gases in the cylinder from leaking