Experiment shafft to be trafnsmitted at fwill to

Experiment No: 8
Study of Transmission System of an automobile



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Tfhe mechfanism
that tfransmits the fpower dfeveloped bfy the efngine of auftomobile to the
drivifng wfheels isf caflled the TfRANSMISSION SYfSTEM


Fufnction of trfansmission sysftem


Profvides mfeans of cfonnection
anfd discofnnection of efngine wfith thef drfive wfheels

Pfrovides mfeans to tfransfer
pfower in ofpposite difrection.

Enfable powfer transmifssion
at varifed fangles and variefd flengths.

Profvide mefans to dfrive
the dfriving whfeels at dfifferent fspeeds wfhen requfired.


Thfe abofve reqfuirementfs
are fuflfillefd by fthe ffollowing mfain unifts off trafnsmission systemf


Gfear Bfox

Shfaft and
Unfiversal Jfoints.


Rfoad Wfheel


Typefs of Trfansmission


Mefchanical tfransmission

Hydrauflic transmissifon


Manuafl transmfission syfstem

In thfis tyfpe off trfansmission syfstem, the drivfer hfas to mfanually
seflect afnd enfgage tfhe geafr rfatios



A clutcfh is
a fmechanfism wfhich enfables the rfotary motfion of fone shafft to be trafnsmitted
at fwill to secfond shfaft, whofse axfis is cfoincident wifth that of ffirst.

Clfutch is lfocated
betfween enginfe anfd gfear boxf. Wfhen the cflutch is fengaged, tfhe powfer flowfs
ffrom the efngine fto the frear whefels thfrough the tfransmission fsystem anfd
thef vehficle fmoves .whenf the clutfch is disfengaged, tfhe powefr is noft trafnsmitted
tfo thef rear whefels and fthe vefhicle stopfs, whilfe thfe efngine is sftill


fClutch fis dfisengaged

a) Stfarting
the efngine,

b)f Shiftingf
the gfears,

c) Idfling
the engfine


Clutfch is enfgaged
onlfy whfen the vfehicle isf to mfove anfd is kepft enfgaged whenf the fvehicle
is movfing.


Functifon of a fClutch:

To permfit
engagfement or disefngagement of a gfear whefn the vehficle is statfionary and
tfhe enginfe is rfunning

To trafnsmit
the engfine powefr to the roafd whefels fsmoothly wifthout shfock to the tfransmission
systfem whilfe setfting the fwheel in mfotion.

To pefrmit
the engagfing of geafrs whfen the vfehicle is in mfotion withofut dfamaging tfhe
gfear wheefls.



of fManual tranfsmission:


fClutch fullyf deprfessed

Thfe cluftch
is fulfly disenfgaged whefn the pfedal is fulfly depresfsed. Tfhere wifll be nfo
tforque befing transfferred ffrom the engifne to tfhe tranfsmission anfd fwheels.
Fulfly depresfsing the clutfch allofws the drifver to chafnge gfears or stfop
the vehifcle.

Cflutch slipsf

Tfhe cflutch
sflips isf the pofint thatf vary betwefen bfeinfg fullfy defpressed and refleased.
The fclutch sflip is ufsed to startf tfhe vefhicle fromf af sftand stilfl. Ift
thefn afllows thef efngine rotatifon to adfjust to the fnewly selefcted gfear
ratiof gfradually. It is refcommended not to slip thfe clutchf for a longf time
fbecaufse a lot of fheat is genefrated refsulting in enefrgy wafstage.

Clutcfh fuflly relfeased

The clfutch
is fullxy engagxed whxen txhe pxedal is fulxly rexleased. Alxl the engixne torxque
willx be tranxsmitted to txhe tranxsmission. Thisx resuxlts inx the powexr bxeing
transxmitted to txhe wheelxs witxh mxinimum losxs.


Hyxdraulic transxmission

Axutomatic txransmission
sysxtem is the mostx adxvanced syxstem in whxich drixves mexchanical exfforts
are rxeduced vexry mxuch and dixfferent speexds are obtxained auxtomatically.
Thisx systemx is genxerally alxso xcalled hydramatic traxnsmission. It containx
epicyclic gexar arrangexment, fluixd xcoupling and toxrque convxerter. In this planetxary
gearxs xsets are placxed in xseries to provixde txransmission.

Thixs tyxpe of txransmission
axre usexd bxy Skoxda ,Txoyota , Lexusx , xetc


Sxtages of axutomatic transmixssion:

Paxrk(P): selxecting the paxrk modxe wxill loxck the transmxission,
thus restxricting the vexhicle

fromx movinxg.

Reverxse( R): sexlecting the rexverse modxe putxs the carx xinto
revexrse gexar, allxowing the

vxehicle to mxove

Nxeutral (N): selexcting nexutral modxe
discoxnnects the xtransmission from the whexel.

Low (xL): selectixng the loxw xmode wxill alxlow yxou txo loxwer
the spexed to movxe on hixlly axnd

mixddy areasx.

Drxive (D : sexlecting dxrive modex allxows the vxehicle to moxve
and acxcelerate throuxgh a raxnge


Fluidx couplxing: A flxuid couplixng is a hydroxdynamic devicxe uxsed to traxnsmit

mechanixcal pxower. Itx has beexn used in auxtomobile traxnsmissions as an axlternative
to a mechaxnical clxutch.