Experiment N0: 8
Study 0f Transmissi0n Sysitem 0f an aut0m0bile
that transmits the p0wer devel0ped by the engine 0f aut0m0bile t0 the driving
wheels is called the TRANSMISSI0N SYSITEM
Functi0n 0f transmissi0n sysitem
Pr0vides means 0f c0nnecti0n
and disc0nnecti0n 0f engine with the drive wheels
Pr0vides means t0
transfer p0wer in 0pp0site directi0n.
Enable p0wer transmissi0n
at varied angles and varied lengths.
Pr0vide means t0 drive
the driving wheels at different speeds when required.
The ab0ve requirements
are fulfilled by the f0ll0wing main units 0f transmissi0n sysitem
Mechanical transmissi0n sysitem
Hydraulic transmissi0n sysitem
Manual transmissi0n sysitem
In this type 0f transmissi0n sysitem, the driver has t0 manually
select and engage the gear rati0s
A clutch is a
mechanism which enables the r0tary m0ti0n 0f 0ne shaft t0 be transmitted at
will t0 sec0nd shaft, wh0se axis is c0incident with that 0f first.
Clutch is l0cated
between engine and gear b0x. When the clutch is engaged, the p0wer fl0ws fr0m
the engine t0 the rear wheels thr0ugh the transmissi0n sysitem and the vehicle
m0ves .when the clutch is disengaged, the p0wer is n0t transmitted t0 the rear
wheels and the vehicle st0ps, while the engine is still running.
c) Idling the
engaged 0nly when the vehicle is t0 m0ve and is kept engaged when the vehicle
Functi0n 0f a Clutch:
engagement 0r disengagement 0f a gear when the vehicle is stati0nary and the
engine is running
the engine p0wer t0 the r0ad wheels sm00thly with0ut sh0ck t0 the transmissi0n sysitem
while setting the wheel in m0ti0n.
T0 permit the
engaging 0f gears when the vehicle is in m0ti0n with0ut damaging the gear
0f Manual transmissi0n:
Clutch fully depressed
The clutch is
fully disengaged when the pedal is fully depressed. There will be n0 t0rque being
transferred fr0m the engine t0 the transmissi0n and wheels. Fully depressing
the clutch all0ws the driver t0 change gears 0r st0p the vehicle.
slips is the p0int that vary between being fully depressed and released. The clutch
slip is used t0 start the vehicle fr0m a stand still. It then all0ws the engine
r0tati0n t0 adjust t0 the newly selected gear rati0 gradually. It is rec0mmended
n0t t0 slip the clutch f0r a l0ng time because a l0t 0f heat is generated
resulting in energy wastage.
Clutch fully released
The clutch is
fully engaged when the pedal is fully released. All the engine t0rque will be transmitted
t0 the transmissi0n. This results in the p0wer being transmitted t0 the wheels with
Aut0matic transmissi0n sysitem
is the m0st advanced sysitem in which drives mechanical eff0rts are reduced
very much and different speeds are 0btained aut0matically. This sysitem is generally
als0 called hydramatic transmissi0n. It c0ntain epicyclic gear arrangement,
fluid c0upling and t0rque c0nverter. In this planetary gears sets are placed in
series t0 pr0vide transmissi0n.
This type 0f transmissi0n
are used by Sk0da ,T0y0ta , Lexus , etc
Stages 0f aut0matic transmissi0n:
Park(P): selecting the park m0de will l0ck the transmissi0n,
thus restricting the vehicle
Reverse( R): selecting the reverse m0de puts the car int0
reverse gear, all0wing the
vehicle t0 m0ve
Neutral (N): selecting neutral m0de
disc0nnects the transmissi0n fr0m the wheel.
L0w (L): selecting the l0w m0de will all0w y0u t0 l0wer the
speed t0 m0ve 0n hilly and
Drive (D : selecting drive m0de all0ws the vehicle t0 m0ve
and accelerate thr0ugh a range
Fluid c0upling: A fluid c0upling is a hydr0dynamic device used t0 transmit
mechanical p0wer. It has been used in aut0m0bile transmissi0ns as an
alternative t0 a mechanical clutch.
applicati0ns, the pump typically is c0nnected t0 the flywheel 0f the engine. The
turbine is c0nnected t0 the input shaft 0f the transmissi0n. While the
transmissi0n is in gear, as engine speed increases t0rque is transferred fr0m
the engine t0 the input shaft by the m0ti0n 0f the fluid, pr0pelling the
vehicle. S0, the behavi0r 0f the fluid c0upling str0ngly resembles that 0f a
mechanical clutch driving a manual transmissi0n.
is a hydraulic transmissi0n which increases the t0rque 0f the vehicle reducing
its speed . It pr0vides a c0ntinu0us variati0n 0f rati0 fr0m l0w t0 high. The
key characteristic 0f a t0rque c0nverter is its ability t0 multiply t0rque when
there is a substantial difference between input and 0utput r0tati0nal speed,
thus pr0viding the equivalent 0f a reducti0n gear. cars with an aut0matic
transmissi0n have n0 clutch that disc0nnects the transmissi0n fr0m the engine.
S0, they use an amazing device called a t0rque c0nverter.
manual transmissi0n and aut0matic transmissi0n:
manual transmissi0n are usually cheaper .
transmissi0n has better fuel ec0n0my . This is because manual transmissi0n has
better mechanical and gear train efficiency.
transmissi0n 0ffers the driver m0re c0ntr0l 0f the vehicle.
aut0matic transmissi0n are c0stlier than th0se 0f manual transmissi0n.
transmissi0n has n0t better fuel ec0n0my . This is because aut0matic transmissi0n
has n0t better mechanical and gear train efficiency as c0mpare t0 th0se 0f aut0matic
transmissi0n d0es n0t 0ffer the driver m0re c0ntr0l 0f the vehicle as c0mpare t0
that 0f aut0matic transmissi0n sysitem.