Lubrication system
Lubrication
System:
Parts
require lubrications Crankshaft bearing Piston pin Timing gears Valve mechanism
Piston ring and cylinder walls Camshaft and bearings.
Purpose
of lubrication:
Reduce friction & wear - by creating a thin film
(Clearance) between moving parts
Seal power - The oil helps form a gastight seal
between piston rings and cylinder walls
Cleaning - Cleans As it circulates through the
engine, the oil picks up metal particles and carbon,
and brings them back down to the pan.
Absorb shock - When heavy loads are imposed on the
bearings, the oil helps to cushion the load
Cooling. - Cools Picks up heat when moving through the engine and then drops
into the cooler oil pan, giving up some of this heat.
Types
Lubrication System:
Petrol system
Splash system
Pressure system
Dry-sump system
Oil
change:
Every 5000Km for four wheeler , Every 2000 Km in two wheeler Ignoring regular
oil change intervals will shorten engine life and performance.
All
internal combustion engines are equipped with an internal lubricating system.
Without lubrication, an engine quickly overheats and its working parts seize
due to excessive friction. All moving parts must be adequately lubricated to
assure maximum wear and long engine life.
petrol
Lubrication;
The
functions of an engine lubrication system are as follows: Reduces friction and
wear between moving parts. Helps transfer heat and cool engine parts. Cleans
the inside of the engine by removing contaminants (metal, dirt, plastic,
rubber, and other particles).
Absorbs
shocks between moving parts to quiet engine operation and increase engine life.
The properties of engine oil and the design of modern engines allow the
lubrication system to accomplish these functions.
Types
of Lubrication Systems;
Now
that you are familiar with the lubricating system components, you are ready to
study the different systems that circulate oil through the engine. The systems
used to circulate oil are known as splash, combination splash force feed, force
feed, and full force-feed.
Splash Systems
The splash system is no longer used in automotive engines. It
is widely used in small four- cycle engines for lawn mowers, outboard marine
operation, and so on. In the splash lubricating system, oil is splashed up from
the oil pan or oil trays in the lower part of the crankcase.
The oil is thrown upward as droplets or fine mist and
provides adequate lubrication to valve mechanisms, piston pins, cylinder walls,
and piston rings. In the engine, dippers on the connecting-rod bearing caps
enter the oil pan with each crankshaft revolution to produce the oil splash.
A passage is drilled in each connecting rod from the dipper
to the bearing to ensure lubrication. This system is too uncertain for
automotive applications. One reason is that the level of oil in the crankcase
will vary greatly the amount of lubrication received by the engine. A high
level results in excess lubrication and oil consumption and a slightly low
level results in inadequate lubrication and failure of the engine.
Combination Splash and Force Feed
In a combination splash and force feed, oil is delivered to
some parts by means of splashing and other parts through oil passages under
pressure from the oil pump. The oil from the pump enters the oil galleries.
From the oil galleries, it flows to the main bearings and camshaft bearings.
The main bearings have oil-feed holes or grooves that feed
oil into drilled passages in the crankshaft. The oil flows through these
passages to the connecting rod bearings. From there, on some engines, it flows
through holes drilled in the connecting rods to the piston-pin bearings.
Cylinder walls are lubricated by splashing oil thrown off from the
connecting-rod bearings.
Some engines use small troughs under each connecting rod that
are kept full by small nozzles which deliver oil under pressure from the oil
pump. These oil nozzles deliver an increasingly heavy stream as speed
increases. At very high speeds these oil streams are powerful enough to strike
the dippers directly. This causes a much heavier splash so that adequate
lubrication of the pistons and the connecting-rod bearings is provided at
higher speeds. If a combination system is used on an overhead valve engine, the
upper valve train is lubricated by pressure from the pump.
Full pressure lubrication
A somewhat more complete pressurization of lubrication is
achieved in the force-feed lubrication system. Oil is forced by the oil pump
from the crankcase to the main bearings and the camshaft bearings. Unlike the
combination system the connecting-rod bearings are also fed oil under pressure
from the pump. Oil passages are drilled in the crankshaft to lead oil to the
connecting-rodbearings.
The passages deliver oil from the main bearing journals to
the rod bearing journals. In some engines, these opening are holes that line up
once for every crankshaft revolution. In other engines, there are annular
grooves in the main bearings through which oil can feed constantly into the
hole in the crankshaft. The pressurized oil that lubricates the connecting- rod
bearings goes on to lubricate the pistons and walls by squirting out through
strategically drilled holes. This lubrication system is used in virtually all
engines that are equipped with semi floating piston pins.
Full pressure
In a full force-feed lubrication system, the main bearings,
rod bearings, camshaft bearings, and the complete valve mechanism are
lubricated by oil under pressure. In addition, the full force-
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