Continuously variable transmission CVT

1. Presenter :
Junaid ahmed (Ned
UNIVERSITY) AUTOMOTIVE
ENGINEERING 09-10

2.  A Continuously variable
transmission (CVT) is a
transmission which can
change steplessly through an
infinite number of effective
gear ratios between
maximum and minimum
values.
Continuously Variable
Transmission

3. Types of CVT
 CVT has been classified into Seven(10) types:
1. Pulley Based CVT’S or Reeves drive
2. Toroidal or roller-based CVT (Extroid CVT)
3. Magnetic CVT or mCVT
4. Infinitely Variable Transmission (IVT)
5. Ratcheting CVT
6. Hydrostatic CVTs
7. Naudic Incremental CVT (iCVT)
8. Cone CVTs
9. Radial roller CVT
10. Planetary CVT

4.  Pulley Based
CVT’S
o In this most
common CVT
system , there are
two V-belt pulleys
that are split
perpendicular to
their axes of
rotation, with a V-
belt running
between them.

5.  Toroidal CVT’S
o Toroidal CVTs
are made up of
discs and rollers
that transmit
power between
the discs.

6.  Hydrostatic CVT’S
o Hydrostatic
transmissions use
a variable displacement
pump and a hydraulic
motor. All power is
transmitted by hydraulic
fluid.

7.  Infinitely Variable
Transmission (IVT)
o A subset of CVT designs
are called infinitely
variable transmissions
(IVT or IVTs)

8.  Cone CVTs
o A cone CVT varies the effective
gear ratio using one or more
conical rollers.

9.  WHY Use CVT……..?
CVT MT
8.8 sec. 11.9 sec.
0-100 Km/h
• The Continuously Variable
Transmission (CVT) proved 35%
more efficient than the Manual
Transmission (MT).
• With same car and engine, the
CVT takes only 75% of the time to
accelerate to 100km/h, compared
to the MT.

10.  Disadvantages of
Gearbox
 Produce jerk to vehicle during
the change of gears.
 Considerable loss of power in
the transmission system.
 Low starting acceleration.
 Considerable driving fatigue

11.  Advantages of CVT
 Constant, stepless acceleration.
 The main advantage of CVTs is
that they allow an engine to run at its
ideal RPM regardless of the speed of
the vehicle.
 There are 25% fewer moving parts
to a CVT transmission.

12.  There are 25% fewer moving parts
to a CVT transmission.
 Less power loss in a CVT than a
typical automatic transmission.
 Responds better to changing
conditions, such as changes in
throttle and speed.

13.  APPLICATIONS
 Many small tractors for home and garden use
simple rubber belt CVTs.
 All snowmobiles, old and new, and motor
scooters use CVTs.
 Audi A4 also uses CVT.
 CVTs have been used in aircraft electrical
power generating systems and in Formula race
cars.

14.  Future Of CVT
 Fuel economy and Emissions
 New fuel regulations.
 Cost

15.  CONCLUSION
 CVT is the most superior
technology for power transmission
 And it would be the widely
acceptable technology throughout
the world.

16.  REFERENCES
 www.Howstuffworks.com
 www.Wikipedia.org
 www.nissan-global.com
 www.autos.aol.com

17. THANK YOU