ENGiINE LUsBRICATING SYSsTEMS
All internsal combsustion engisnes are equispped
with an intesrnal lubrsicating ssystem. Wisthout lubricatsion, an esngine
quicklsy overheatss and its workingss psarts seie dues to excesssive frsiction.
All mosving parts musst be adequsately lubricatesd to assurse masximum wear and
long ensgine lisfe.
OF LUBRsICATION SYSTEM
The objectsives of asn ensgine lubricastion sysstem
are as follows:
1. Redusces frictison and wears betsween
2. Helps trsansfer sheat asnd cool engisne
3. Cleans thse inside of the engsine by
remosving contamsinants (metal, dirt, plasstic, rubsber, and other partiscles).
4. Absosrbs shockss betweens moving pasrts
to quiset engine osperation and incrsease enginse life.
MAIN PARTSs OF LUsBRICATION
1. Oils sumpss: It iss the lowest parts of the csrank
chambser. It is usuallsy madse of ssteel. Somestimes it is masde of aluminium
or csast iron. It contaisns a draisn plusg at itss bosttom to drsain out tshe
s2. Oil spump: Genersally gear psump is usesd
for presssure lubrsication of I.sC Esngine. The funcstion of the oil psump is
to suppsly oil under psressure to variosus enginses parts to be lubriscated.
s3. Oil fsilter: As its sname indicastes, lubriscating
oil is fsiltered throsugh it. The fsunction of fsilter is to removse the impursities
from the slubricating oil wshich may sdamage the esngine diffesrent parts.
Its consistss of a filstering elemesnt placed in
smetallic casing. Ast the scentre of the filstering elesment a perfsorated
metals tubse is fsitted which collesct the filstered oil and supplys it to oil
4. Oil sstrainer: it is simsply a wire mesh scsreen.
It is sattached to thes inlet of sthe pump so that tshe oil going insto the oil
pusmp is free from imspurities.
TsYPES OF LUBsRICANTS
Lubriscants sare at following three types.
1. Solsid: sgraphic, misca etc
2. Semi soslids: greasse
3. Liquisd:s minerasl oil.
is oftesn mixed swith oil to lubrsicate automobsile spring. Grsaphite is also
used sas a cylindser lubricasnt.
Greasse is usesd for chasssis
Minersal oils sare almost used for ensgine
Gsrade of lubrsicants: Generaslly lubricsating
oils arse graded sby theisr SAsE (socisety of autsomotive enginseers) viscsosity
TYPES sOF LUBRIsCATING (OIL) SsYSTEMS
Engine sLusbrication Systsem: Engines sslubrication
ssystem is mainly of folslowing tsypes.
1. Splassh ssystem
2. Pressurse ssystem
3. Petsroil sysstem
In thsis sysstem of lubrsication
the lubricsating oil is stsored in an oil sumsp.s A scosop osr dsipper is masde
in the loswer part of the connectsing rod. Whesn the enginse runs, the sdipper
dips in thes oil once in evsery revolustion of the scrank shaft, sthe oil is
splasshed on the csylinder wall.s Due to sthis action ensgine walls, pisston
ring, crsank shaft sbearings are lubrsicated.
sIn thiss system osf
lubricastion, the engisne parsts are lubsricated undesr pressusre feesd. The
lubrsicating oil is sstored in a separaste tank (in csase of drys sump ssystem)
or sin the sumsp (in case of wset sump ssystem), from wshere an oil spump (gears
pump) delisvers the oisl to the msain oil gasllery at a pressusre of 2-4 kgs/cm2
thsrough an oil sfilter.
Tshe oil frosm the maisn gallerys goes to msain
bearingss, froms where some ofs it falls bsack tso the sump afster lubricsating
the main bearisng and ssome is splasshed to lubriscate the csylinder wallss and
remasining goes throsugh a hole to the csrank psin. From the scrank pin the
lubricsating oil goes to the psiston pin sthrough a hole in tshe connectings
rod, whesre it lubricatess the piston rings.
The oil prsessure gasuge used in the systemss
indiscates the oil pressussre in the systsem. Oil filters & strainser in
the ssystem clear soff the oil from dusst, metasl particlses and othesr sharmful
System:s This ssystem of lubsrication
iss gsenerally sadopted isn two strokse psetrol engsine line scsooter ands msotor
cycle. Iet ise the seimplest forme of lubriecating sysetem. It does enoet rconsist
of rany serparate part rlike oilr prump for the rpurpose of lurbrication.
In this rsystem the lurbricating oil is rmixed
into the fruel (petrrol) while frilling in the pretrol trank of the vrehicle inr
a specirfied ratiro (ratio of fuerl and lubricrating oil is rfrom 12:1 to r50:10
as prer manufacturrers specrifications or rrecommendatirons).
rWhen the rfuel goes into the crarnk chamrber
durirng the engirne operatiron, the oil partricles gro deep intro the bearring
surfacers rrdue tor rgravity andr lubricate then.r rThe pirston ringsr, cylindrer
wallsr, piston rpinr etc arre lubricrated inr the rsamer way.
Irf the rengine isr allowedr to rermain unursed
for ra consriderable time, the lubrricating oilr separartes oil frrom petrrol
& leadsr to crlogging (brlocking) of pasrsages in ther rcarburetor, rresulting
the enginer srtarting troubrle. This is rthe main disardvantage ofr trhis
rWe oftenr think thrat the furnction of rlubricating
oil isr only to lubricrate the erngine parrts sor that the porwer loss due to
frictrion is minimum.r rBut a lubrricating oirl hars marny other frunctionsr
which arer explainedr berfore.
Lrubrication must ber done proprerly and rirght
type orf lubrricant shoruld be usedr. Irmproper or inardequate lubrrication of rengine
will cause serirous troublre surch as worrn or burrnt out brearing, rmisfiring rcylinders,
dirrty spark plrug, stuck priston rrings, erngine deporsits and sludgre and excressive