engine friction and lubrication system
TRANSCRIPT
-
7/27/2019 Engine friction and lubrication system
1/11
-
7/27/2019 Engine friction and lubrication system
2/11
10/19/2013
-
7/27/2019 Engine friction and lubrication system
3/11
An internal combustion engine would not run for even a few minutes if themoving parts were allowed to make metal-to-metal contact. The heat
generated due to the tremendous amounts of friction would melt the metals,
leading to the destruction of the engine. In the engine, the piston rings
generate friction against the cylinder walls. Friction opposes momentum
and mechanical energy. Friction creates heat and reduces the mechanical
energy of the piston as it is pushed downward to turn the crankshaft.
10/19/2013
-
7/27/2019 Engine friction and lubrication system
4/11
We can define Frication as an opposite force
or reaction force between two relativesurfaces when they are in motion.
Friction is a force between two surfaces that
are sliding, or trying to slide across oneanother.
From the law of Friction we know that,
F = Rn
Where, F= Frictional force= Coefficient of frictionRn= Normal reaction between
the two surfaces
10/19/2013
-
7/27/2019 Engine friction and lubrication system
5/11
1) Piston & Cylinder AssemblyFriction
2) Bearing Friction
3) Crank Shaft Friction4) Reciprocating Friction
5) Valve train Friction
6) Auxiliary component friction
7) Pumping losses.
10/19/2013
-
7/27/2019 Engine friction and lubrication system
6/11
10/19/2013
Using piston with Less masslowers the piston inertia and
reduces acceleration. And shorterskirt. Because shorter piston skirtsreduce rubbing friction because ofthe smaller surface contact area.
Using fewer and thinner pistonrings but require closer tolerances.To reduce resistance of surface-to-surface motion, lubricating oilmust be added to the spacebetween the surfaces.
Use new lubricating oil to avoidingwear of the engine. Piston pin
Side
Thrust
Cylinder Gas
Pressure
Piston rings
-
7/27/2019 Engine friction and lubrication system
7/11
We can define lubricationis reduction of friction byhydraulic floating. It holdsan adequate supply of oilto cool, clean, lubricate,and seal the engine. It also
removes contaminantsfrom the oil and deliversoil to all necessary areasof the engine.
10/19/2013
-
7/27/2019 Engine friction and lubrication system
8/11
Reducing frictional resistance
Lubricant decreases friction by preventing direct contact of
two rubbing surfaces by supplying some fluid substance between
them thereby it increase the power output and the engine service
life.
Cooling
Lubricant also acts as a coolant carrying heat away from the
bearings, cylinders and pistons.
Cleaning
Lubricant cleans carbon and other deposits from the surfaces of
the piston, piston rings and bearings. It also eliminates dust and
other contaminants.
10/19/2013
-
7/27/2019 Engine friction and lubrication system
9/11
Mist lubrication system orpetrol lubrication system
Wet sump lubrication system Splash system
Pressure feed system
Splash and Pressure lubrication system
Dry sump lubrication system
10/19/2013
Fig: Mist lubrication system or petrol lubrication system
-
7/27/2019 Engine friction and lubrication system
10/1110/19/2013
Fig: Pressurefeed Lubrication system.Fig: Dry-sump Lubrication system.
-
7/27/2019 Engine friction and lubrication system
11/11
Experimental data from motored and fired engine tests
indicate that the majority of engine friction is a result of
the piston ring assembly, followed by the engine
bearings/seals, various engine accessories, and finally,
valve train friction.
Multigrade oil reduces engine friction by using
lubrication systems.
10/19/2013