• TYPES OF CVT
• CVT VS AT
CVT is an advanced technology of automatic transmission.
Unlike traditional automatic transmissions, continuously variable
transmissions don't have a gearbox with a set number of gears.
CVT also known as single-speed transmission, gearless
transmission, one-speed automatic, variable pulley transmission.
Varies the transmission ratio continuously.
Shifts automatically with an infinite number of ratios.
• Leonardo da Vinci sketches is the basis for the first
continuously variable transmission in 1490.
• First patent for the CVT Transmission was made by Daimler &
Benz in 1886.
• The first workable belt driven CVT was designed and built by
the Dutchman Huub van Doorne in 1958.
• In Early 1990's Nissan introduced CVT in their Nissan March
TYPES OF CVT
1. Pulley based CVT
2. Cone CVT
3. Toroidal CVT
4. Hydraulic CVT
PULLEY BASED CVT
• It consist of main 3 parts
1. PULLEY BASED CVT
• Low Gear • Top Gear
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
Fig 1.4a: Cone CVT showing the initial position of the belt as it
grips the driver shaft (lower) and the driven shaft (upper).
Fig 1.4b: Cone CVT showing the intermediate position as the belt
moves to the right with increase in rpm on the driver shaft.
Fig 1.4c: Cone CVT showing the final position of the belt as it has
moved to the end on right due to increase in rpm on the driver shaft
3. TOROIDAL CVT
• Toroidal CVTs are made up of discs and rollers that transmit
power between the discs by means of tractive force.
• A viscous fluid(EHL) is placed between the rollers and discs.
• The change in angle by a roller must be mirrored by the
• The position of the rollers is controlled hydraulically.
4. HYDRAULIC CVT
• It consist of variable-displacement pumps and hydraulic motor.
• In this type of transmission, the rotational motion of the engine
operates a variable-displacement pumps on the driving side.
• The pump converts rotational motion into fluid flow.
• A hydraulic motor located on the driven side, the fluid flow is
converted back into rotational motion.
• Allow for an infinite number of gear ratios.
• Eliminates "shift shock" -- makes it smoother ride
• Responds better to changing conditions.
• Better fuel economy & power loss than automatic transmission
• 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 fewer moving parts to a CVT transmission.
• Limited torque capacity as compared to the manual
• More costlier than manual transmission
• Slipping in the drive belt or pulleys.
• Additional gear train required for reverse condition.
• Commonly used in automobiles
• New continuous variable transmission for medium duty trucks
• Starts development on wind turbine cvt
• The applications and benefits of continuously variable
transmissions can only increase based on today’s research and
• With an increase in the number of companies opting for CVTs
there will be a consequent decrease in the cost of the vehicle as
well as the transmission.
• Nilabh Srivastava, Imtiaz Haque, “A review on belt and chain continuously
variable transmissions (CVT): Dynamics and control” ,Mechanism and
Machine Theory, Volume 44, Issue 1, January 2009, Pages 19-41.
• Mr. Jadhav S. S Prof. Hanamapure N. S, “ Toroidal Drive System for
Vehicle Transmission Control”, IJSRD - International Journal for Scientific
Research & Development| Vol. 2, Issue 09, 2014 | ISSN (online): 2321-0613.
• Da Wen Ge, Sugeng Ariyono and Daw Thet Thet Mon, “ A REVIEW ON
CONTINUOUSLY VARIABLE TRANSMISSIONS CONTROL”, National
Conference in Mechanical Engineering Research and Postgraduate Students
(1st NCMER 2010) 26-27 MAY 2010