The document discusses continuous variable transmissions (CVTs). It explains that CVTs provide an infinite number of gear ratios compared to traditional transmissions which have discrete gears. This allows the engine to run at optimal RPMs for efficiency. CVTs also provide seamless acceleration and improved fuel economy compared to automatic transmissions. While CVT technology is still developing, it is emerging as the preferred transmission type due to its advantages over other transmission options.
CVT transmission can change seamlessly through an infinite number of effective gear ratios between maximum and minimum values giving jerk free driving experience.
In this presentation we mainly discuss about Variable-diameter pulley (VDP) and how basically it functions.
CVT transmission can change seamlessly through an infinite number of effective gear ratios between maximum and minimum values giving jerk free driving experience.
In this presentation we mainly discuss about Variable-diameter pulley (VDP) and how basically it functions.
A continuously variable transmission (CVT) (also known as a single-speed transmission, stepless transmission, pulley transmission, or, in case of motorcycles, a twist-and-go) is an automatic transmission that can change seamlessly through a continuous range of effective gear ratios. This contrasts with other mechanical transmissions that offer a fixed number of gear ratios. The flexibility of a CVT allows the input shaft to maintain a constant angular velocity.
A belt-driven design offers approximately 88% efficiency, which, while lower than that of a manual transmission, can be offset by lower production cost and by enabling the engine to run at its most efficient speed for a range of output speeds. When power is more important than economy, the ratio of the CVT can be changed to allow the engine to turn at the RPM at which it produces greatest power. This is typically higher than the RPM that achieves peak efficiency. In low-mass low-torque applications a belt driven CVT also offers ease of use and mechanical simplicity.
A continuously variable transmission (CVT) (also known as a single-speed transmission, stepless transmission, pulley transmission, or, in case of motorcycles, a twist-and-go) is an automatic transmission that can change seamlessly through a continuous range of effective gear ratios. This contrasts with other mechanical transmissions that offer a fixed number of gear ratios. The flexibility of a CVT allows the input shaft to maintain a constant angular velocity.
A belt-driven design offers approximately 88% efficiency, which, while lower than that of a manual transmission, can be offset by lower production cost and by enabling the engine to run at its most efficient speed for a range of output speeds. When power is more important than economy, the ratio of the CVT can be changed to allow the engine to turn at the RPM at which it produces greatest power. This is typically higher than the RPM that achieves peak efficiency. In low-mass low-torque applications a belt driven CVT also offers ease of use and mechanical simplicity.
Nostalgia. Assignment for seminar in Prof. Rajat Mehrotra's class.
Those days citing sources in presentation was not the norm.
Image credits are from my then night time love website CarBibles.com of old. It can be accessed on Internet Archive. It was a treasure trove of automotive information lighting a seekers mind first time to the anatomy of automotive technology. https://web.archive.org/web/20090224063513/http://www.carbibles.com/suspension_bible.html
Countless late hours were spend devouring every word replaying every animation reading every updated chapter religiously.
I hope Chris rides the bike of his dreams now.
Analysis, Design and Application of Continuously Variable Transmission (CVT)IJERA Editor
Continuously Variable Transmission (CVT) offers a continuum of gear ratios between desired limits. This allows the engine to operate more time in the optimum range. In contrast, traditional automatic and manual transmissions have several fixed transmission ratios forcing the engine to operate outside the optimum range. The need for a transmission system and the working principle of CVT has been discussed in depth. An attempt has been made to understand the contribution of Hydraulic Actuators, which is an integral part of a CVT. Furthermore, the question of how and why a Torque Converter has effectively replaced a conventional clutch has been answered. The materials used, constructional aspects and stress analysis of the belt has been discussed in detail. A graphical comparison of fuel efficiency between a manual transmission and a CVT in different high end vehicles is included. Recent developments in clamping force control for the push belt Continuously Variable Transmission (CVT) have resulted in increased efficiency in combination with improved robustness. Current control strategies attempt to prevent macro slip between elements and pulleys at all times for maximum robustness.
final year project report by mechanical engineering student of career point university kota. The Soft Car design proposal has swing 90 degrees. It can pull up alongside a parking space and drive in sideways.
Let’s go through this slide to know the basic functions of a car’s transmission system, what designs of transmission are available, different types of transmission and finally which one is the most efficient transmission for upcoming vehicles. It would definitely help you out with valuable info.
Front Wheel Steering System With Moveable HeadlightsSuchit Moon
This is Mechanical project report on Front wheel steering system with moveable headlights with latest
electronics technology. The most standard steering arrangement is to show the front wheels employing
a hand–operated handwheel that is positioned before of the motive force, via the steering column, which
can contain universal joints to permit it to deviate somewhat from a line. alternative arrangements ar
generally found on differing types of vehicles, as an example, a tiller or rear–wheel steering. tracked
vehicles like tanks sometimes use differential steering — that's, the tracks are created to maneuver
at completely different speeds or maybe in opposite directions to originate a amendment in fact.
SELECTION OF GEAR BOX FOR VARIOUS MECHANICAL SYSTEMSANDIP THORAT
Automotive gearboxes are used to reduce load on the engine by manipulating torque and speed. They have the option to select one of several different gear ratios.
Once the engine has reached a number of revolutions per minute, it is advisable to increase the gear to reduce the engine rpm to reduce wear on the engine, allow more control, and greater speeds, better acceleration, and better fuel economy.
Automotive gearbox also have the provision to do the opposite ie provide an increase in output shaft speed with a reduction of torque.
Most gearboxes are used to increase torque & reduce the speed of a output shaft. This produces a mechanical advantage .
Automotive gearboxes are used to reduce load on the engine by manipulating torque and speed. They have the option to select one of several different gear ratios.
Once the engine has reached a number of revolutions per minute, it is advisable to increase the gear to reduce the engine rpm to reduce wear on the engine, allow more control, and greater speeds, better acceleration, and better fuel economy.
Automotive gearbox also have the provision to do the opposite ie provide an increase in output shaft speed with a reduction of torque.
Most gearboxes are used to increase torque & reduce the speed of a output shaft. This produces a mechanical advantage .
Automotive gearboxes are used to reduce load on the engine by manipulating torque and speed. They have the option to select one of several different gear ratios.
Once the engine has reached a number of revolutions per minute, it is advisable to increase the gear to reduce the engine rpm to reduce wear on the engine, allow more control, and greater speeds, better acceleration, and better fuel economy.
Automotive gearbox also have the provision to do the opposite ie provide an increase in output shaft speed with a reduction of torque.
Most gearboxes are used to increase torque & reduce the speed of a output shaft. This produces a mechanical advantage .
2. The job of the transmission is
to change the speed ratio
between the engine and the
wheels of an automobile.
The transmission uses a range
of gears -- from low to high -- to
make more effective use of the
engine's torque as driving
conditions change. The gears
can be engaged manually or
automatically.
3. An automatic transmission
is an automobile gearbox
that can change gear
ratios automatically as the
vehicle moves, freeing the
driver from having to shift
gears manually.
5. • This unique transmission does not have several set of gears like most
transmissions, but rather have an infinite number of gear ratios.
• CVT does not strictly require the presence of a clutch, allowing the
dismissal thereof.
• Seamless acceleration with a “direct” drive feel for enhanced driving
pleasure.
• With fewer moving parts, CVT is simpler than Automatic Transmission
in principle.
• CVT is emerging as a keystone technology that enables other
6. o 1490 - Da Vinci sketches a stepless continuously variable
transmission
o 1886 - First Toroidal CVT patent filed
o 1935 - Adiel Dodge receives U.S. patent for Toroidal CVT
o 1939 - Fully Automatic Transmission based on Planetary gear
system introduced
o 1958 - Daf (of The Netherlands) produces a CVT in a car
o 1989 - Subaru Justy GL is the first U.S.-sold production
automobile to offer a CVT
o 2002 - Saturn Vue with a CVT debuts; first Saturn to offer CVT
technology
o 2004 - Ford begins offering a CVT
7. o Provide engine torque in optimum condition (road
loads / drive shaft torque)
o No shift clonk
o Transmission ratio can be adjusted continuously
o Improved fuel efficiency
o Better acceleration
o Eliminates gear hunting especially when going up
a hill
8.
9. Audi A4, a5, A6, A7
Fiat Punto, Ford Fiesta
Honda City, Jazz
Mercedes Benz A & B Class
Nissan Micra
Suzuki SX4
Toyota Prius
11. The variable-diameter pulleys
are the heart of a CVT. Each
pulley is made of two 20-degree
cones facing each other. A belt
rides in the groove between the
two cones.
V-belts are preferred if the belt is
made of rubber. V-belts get their
name from the fact that the belts
bear a V-shaped cross section,
which increases the frictional
grip of the belt.
13. o Driving gear, as in the name it is
situated at the driving side of the
pulley based continuous variable
transmission system. The driving
gear is the most complex parts of
pulley based continuous variable
transmission system. It comprises
of many types gears system and
clutch.
o It comprises of planetary gears,
annular gear, sun gear, and two
different sets of clutch system –
Forward gear clutches and
Reverse gear clutches.
15. The primary pulley is situated at
the driving side of the pulley based
continuous variable transmission
system. It supports the driving
gear and belt from maintaining its
position at different situations.
17. The driving and driven shaft are the base of pulley based
continuous variable transmission system.
The driving and driven shaft are at the driving and driven side of
the pulley based continuous variable transmission system.
19. There are two secondary pulley
in the pulley based continuous
variable transmission system.
Both the secondary pulleys are
situated at the driven end of the
pulley based continuous
variable transmission system. It
is at both situated on the driven
shaft facing opposite to each
other.
22. The common characteristic of
the V-belt drives is the use of
a drive and driven sheave,
each with variable diameters.
The effective diameter of the
sheave is adjusted by varying
the distance between the two
halves of the sheave .
24. In low gear ratio the radius of the
belt in minimum at driving end
and maximum at driven end.
Low speed due to minimum
radius at of belt at driving end
26. If we compare continuous
variable transmission system
with a 6-speed manual
gearbox then we can say the
semi-intermediate gear ratio is
somewhat similar to 2nd gear
of the 6-speed manual
gearbox.
At this stage the radius of the
belt is somewhat 40-60
position, 40 at driving end and
60 at driven end.
28. At this stage the radius of the belt
is somewhat 50-50 position, 50 at
driving end and 50 at driven end.
At this stage the distance
between the driving gear and the
primary pulley at the driving end
and the distance between the two
secondary pulleys at the driven
becomes equal.
The belt radius is equal at both
end.
30. If we compare continuous
variable transmission system with
a 6-speed manual gearbox then
we can say the semi-high gear
ratio is somewhat similar to 4th
gear of the 6-speed manual
gearbox.
This stage just opposite to the
semi-intermediate stage.
32. This stage just opposite to the
first stage i.e., at low gear.
If we compare continuous
variable transmission system with
a 6-speed manual gearbox then
we can say the high gear ratio is
somewhat similar to 5th gear of
the 6-speed manual gearbox.
34. The main advantage of CVTs is
that they allow an engine to run
at its ideal RPM regardless of
the speed of the vehicle. This
improves fuel economy and by
effect, exhaust emissions.
CVT equipped vehicles
consumes 10% less fuel when
compared with the automatic
transmissions.
(from Nissan motor’s journal)
35. Wider gear ratio range.
In CVT, the gear ratio range from low to high gear is expanded,
attaining a top-of-class final gear reduction ratio of about 6.
The extended low end of the range to improve acceleration,
and the high end to improve fuel economy.
Flexibly tunable to match engine characteristics, thereby
enabling optimization of the balance between combustion
efficiency and acceleration.
36. 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.
37. Many small tractors for home and garden use simple rubber
belt CVTs.
All snowmobiles, old and new, and motor scooters use CVTs.
Some combine harvesters have CVTs.
CVTs have been used in aircraft electrical power generating
systems and in Formula race cars.
Some drill presses and milling machines contain a pulley-based
CVT.
38. Much Of The Existing Literature Is Quick To Admit That The
Automotive Industry Lacks A Broad Knowledge Base Regarding
Cvts. Whereas Conventional Transmissions Have Been
Continuously Refined And Improved Since The Very Start Of The
20th Century, CVT Development Is Only Just Beginning. As
Infrastructure Is Built Up Along With Said Knowledge Base, Cvts
Will Become Ever-more Prominent In The Automotive Landscape.
Even Today’s Cvts, Which Represent First-generation Designs At
Best, Outperform Conventional Transmissions. Automakers Who
Fail To Develop Cvts Now, While The Field Is Still In Its Infancy,
Risk Being Left Behind As CVT Development And Implementation
Continues Its Exponential Growth. Moreover, Cvts Are Do Not Fall
Exclusively In The Realm Of IC Engines.
39. CVT is the most superior technology for power transmission.
And it would be the widely acceptable technology throughout
the world.
40. Prepared By –
ANDALIB SHADAN
DEBJIT PAL
SIDDHARTHA SAHA
SUBHASISH BHADRA
SUMIT KUMAR
CHOUDHARY
WARIS AHMED