ASSIGNMENT NO 07 ENGINE LUBRICATION SYSTEM 7.1 DEFINIT DEFINITION ION
The method of reducing friction by introducing the substance called lubricant between the mating parts is called lubrication. 7.2 OBJECTIVES OF LUBRICATION: LUBRICATION:
To Reduce wear and tear To Provide Cooling to the Engine To Provide sealing action To absorb shock between bearing and other engine parts To Reduces friction between moving parts To Reduce corrosion and Carbon deposits To reduces vibration by formation of lubrication film To reduce the noise created by moving parts To Provide cleaning of various part
7.3 COMPONENTS OF IC ENGINE TO TO BE LUBRICATED: LUBRICATED:
Cylinder ,piston ,piston rings and piston pins Crankshaft and Crank Pin Small end and big end bearing of connecting rod Cam , Cam shaft and its bearings !alves Timing gears
7.4 TYPES OF OF LUBRICA LUBRICANTS: NTS:
Sol! l"#$%&'() E.g. graphite, molybdenum, mica S*+,)ol! l"#$%&'() E.g. "eavy #reases L-"! l"#$%&'() E g. $ineral oils, !egetable !egetable %il, &inseed, Caster and 'nimal %il
7. PROPERT PROPERTIES IES OF LUBRICANTS: LUBRICANTS:
!iscosity !iscosity inde( Cloud point and Pour point )lash point and fire point Specific gravity 'cidity Carbon Residue %iliness
7./ REUIREMENT OF AN IDEAL LUBRICANT LUBRICANT::
Prevent wear on bearing &eaves no carbon residue Cleanse the interior of the engine *t should not form an emulsion with water *t should be free from dirt and water *t should not contain Sulphur "ave low consumption rate Should have very less tendency to o(idation &ow cost "igh film strength to prevent sei+ure when heavy load
7.7 ADDITIV ADDITIVES: ES:
'dditives are the compound added to lubricant oil to promote and improve their desired properties. Some of additives are -. V)%o)( '!* +$o*$) additives which improves the viscosity lubricating oils /. A'(o!&'() which reduces the o(idation of lubricating lubricating oils 0. A'(5*&$ &'! D*(*$6*'( additives which serve cleansing and sticking of piston rings 7. TYPES OF LUBRICATION LUBRICATION SYSTEM FOR IC ENGINES
-. $ist $ist or Charge Charge lubri lubricat cation ion system system /. 1et sump sump lubr lubrica icatio tion n syste system m 0. 2ry 2ry sump sump lubr lubric icat atio ion n syste system m 7..1
MIST OR C8ARGE C8ARGE LUBRIC LUBRICA ATION TION SYST SYSTEM: EM:
*n mist lubrication system the lubrication is provided by the mist of lubricating oil This system is employed for two Stroke Petrol engine The petrol and lubricating oil 3/4 to 045 are previously mi(ed in the the fuel tank from where it is supplied to Carburettor. The mi(ture finds its way to all working parts of the engine like cylinder, piston, piston rings, Crank case etc. The petrol gets evaporated and lubricating oil lubricates these various parts. Petrol and lubricating oil has fi(ed proportion - litre to 67 cc *f the engine has crankshaft bearing as plain instead of ball then there is separate oil cups provided
M)( L"#$%&(o' S)(*+ A!&'(&6*) o9 (* M)( l"#$%&(o' ))(*+:
*ts *ts economic and cheap *t needs no oil pump, filters and piping The probability of lubrication failure is least 8uantity of oil is automatically regulated as per the speed and load of the engine
D)&!&'(&6*) o9 (* M)( l"#$%&(o' ))(*+:
7..2 7..2
*ncrease in carbon deposits due to burning of oil 9eeds increased maintenance due to formation of carbon deposits Spark plug fouling due to carbon deposits %il consumption is high 2uring no load running mi(ture of. %il reach to the parts of engine is very small ;ET SUMP SUMP LUB LUBRI RICA CATI TION ON SYS SYSTE TEM: M:
*n the wet sump lubrication system the bottom of the crankcase contain oil pan called Sump which contains lubricating oil which serves as a reservoir to supply lubricating oil to all the parts of *C engine. 'fter lubricating the parts of the engine the oil flies back to sump by gravity and oil is recirculated again. T*$* &$* ($** (*) o9 ;*( )"+ l"#$%&(o' ))(*+
Splash lubrication system Splash and pressure feed system )ully pressure feed system
7..2.1 SPLAS8 LUBRICA LUBRICATION TION SYSTEM
The system is suitable for small capacity of four Stroke engine with moderate speed and bearing loads.
*t consists of sump containing lubricating oil. The end of connecting rod has scoop. 1hen the piston moves from T2C to :2C, the scoop splashes the lubricating oil to the wall of cylinder and various parts such as main bearing, camshaft, bearing, timing gears, piston, cylinder liner etc. 'fter lubrication the splashed oil falls back into the sump..
Sl&) L"#$%&(o' S)(*+
(Reference: R.K. Rajput) 7..2.2 FULLY FULLY PRESSURE FEED SYSTEM
This system is suitable for all types of modern engines including heavy duty engines. The schematic diagram of system is shown in fig
F"ll P$*))"$* L"#$%&(o' S)(*+ (Reference: R.K. Rajput)
*n this method the lubricating oil is fed to va rious parts under pressure ranging from / to ; bar pressure with the help of an oil pump driven by the crankshaft of the engine. The oil from the sump is drawn by the pump through filters and it is forced to the main bearings and the caps of other bearings through the branches of a distributor header ' pressure pressure relief valve 3not shown5 is provided on the delivery side of the pump to return the e(cess oil to the sump if the pressure e(ceeds the predetermined value. 2rilled passages 3shown by dotted lines5 help to provide lubricating o il from the main bearing to the crank pin and it lubricates the big end bearings
7..2.3 SPLAS8 AND PRESSURE PRESSURE FEED SYSTEM
Splash system is not sufficient in case of bearing loads are high. )or this reason, the lubricating oil under pressure is supplied by the oil pump to the main and crankshaft bearing as shown in figure. %il pump also supplies oil under pressure to pipes which directs a stream of oil against the dippers on the connecting rod bearing cups. %ther parts of the engine are lubricated by splash of oil thrown up by the dippers. This system provides sufficient lubrication to all parts and is favored by most of the engine manufacturers. This is used in most heavy duty and highspeed engines.
Sl&) &'! P$*))"$* L"#$%&(o' S)(*+
(Reference: H.N. Gupta) 7..3 7..3
DRY DRY SUMP SUMP LUBR LUBRIC ICA ATION TION SYSTE SYSTEM M
2ry sump is similar to the wet sump method e(cept that in this case the lubricating oil is maintained in a separate tank kept kep t behind the radiator. The general arrangement of dry sump lubrication system is shown in the figure.
D$ S"+ L"#$%&(o' S)(*+
.
(Reference R.K. Rajput)
*n this system the oil contained in the sump is drawn by the pump through the strainer. strainer. This oil after passing through a filter is supplied to supply tank kept outside the cylinder block. The function of the filter is to remove from oil the abrasive particles up to -7 to -6 -6 microns that causes the wear of working surfaces and also to prevent sludge deposits to the bearings %il from storage storage tank is pumped to the engine cylinder cylinder and bearings through an oil cooler. The system uses a pressure relief valve to prevent e(cessive pressure build up after a cold start of the engine.
A!&'(&6*)
*mprovements to vehicle handling and stability. The vehicle
D)&!&'(&6*)
2rysump systems add cost, comple(ity, and weight The e(tra pumps and lines in drysump engines re=uire additional oil and maintenance The large e(ternal reservoir and pumps can be tricky to position around the engine and an d within the engine bay due to their si+e *nade=uate upper valve train lubrication can also become an issue issue if too much oil vapor is being pulled out from the area, especially with multistaged pumps.
D99*$*'%* B*(5**' ;*( S"+ &'! D$ S"+ L"#$%&(o' S)(*+)
2ry sump system is similar to wet sump method e(cept that in this case the lubricating oil is maintained in a separate tank kept behind the radiator. The oil is kept cool because beca use of air blast thrown on the radiator The oil from the tank is supplied by b y the oil pump under a pressure of 0 > bar to various parts of the engine through a distributor header covering the entire cylinder block. Since the temperature rise of lubricating oil in case of dry sump method is less than the wet sump method due to cooling, coo ling, this system permits the use of thinner oil compared to wet sump method. This is an added advantage over wet sump method since the thinner oils reduce the viscous friction loads on the engine.
7.< 7.<
CLAS CLASSI SIFI FICA CATI TION ON OF OF LUB LUBRI RICA CATI TING NG OIL OILS S
The lubricating oils are normally classified according to their viscosity. The S'E 3Society of 'utomotive Engineers5 method of assigning number to different oils id used universally. S'E, 61, -71, /71 grades are defined in terms of viscosity at -> degree centigrade and are the oils which render starting of engine in cold weather easy. S'E /7,07,;7,and 67 grad grades es are are defi define ned d in term termss of visc viscos osit ity y at ?? degre degreee cent centig igra rade de @the @these se oil oil work work satisfactorarily in normal and hot climates. S'E viscosity number
61
- 71
- 61
/ 71
0 71
; 71
6 71
!iscosity units
!iscosity Range 't ->A7C
't ??A7C
$in.
$a(.
$in.
$a(.
Centipoise
-/77
SBS
77
Centipoise
-/77
/;77
SUS
777
-/777
Centipoise
/;77
?77
SUS
-/777
;>777
Centipoise
6 .D
? .
SUS
;6
6>
Centipoise
? .
- / .?
SUS
6>
D7
Centipoise
-/.?
- .>
SUS
D7
>6
Centipoise
-.>
/ / .D
SUS
>6
--7
U'*$)( "*)(o'):
-. Classific Classification ation of lubricatio lubrication n oils 3S'E 3S'E Rating Rating 532e 532ecc -;5 /. Comparison Comparison between between dry dry sump and and wet sump sump lubricat lubrication ion system system32e 32ecc -65 0. 1hat are the the functions functions of lubrica lubricationF tionF State State re=uired re=uired properti properties es of lubricati lubricating ng oil..3$ay -5 ;. Re=uirement Re=uirementss of cooling cooling and lubrica lubrication tion system system3 3$ay $ay -D5
