14-06-2012, 04:11 PM
CONTINUOUSLY VARIABLE TRANSMISSION
CVT.pptx (Size: 1.67 MB / Downloads: 80)
INTRODUCTION
Method of transferring power from an engine
Provides outstanding efficiency and smooth, powerful driving performance.
Constant transfer of power to the driven object
EVOLVEMENT OF CVT
Sketched by Leonardo da Vinci in 1490
Old idea that has only recently become a bastion of hope to automakers
Advancements in fuel economy and emissions triggered the R&D of CVT.
If consumers are buying millions of cars with conventional transmissions, why spend billions to develop and manufacture CVTs?
TOROIDAL
Developed by Nissan
Applicable for engines capacity more than 3.0litres
Transmissions use high shear strength of viscous fluids to transmit torque between i/p torus & o/p torus.
By changing the tilt of the power rollers continuously, the EXTROID CVT executes smooth, continuous gear ratio changes.
Power rollers controlled by hydraulic pressure.
BELT DRIVE/PUSH BELT CVT
Uses segmented steel blocks stacked on a steel ribbon.
Transmits power by means of two pulleys and a steel belt
1 pulley receives torque generated from engine and other pulley transmits drive torques to tires.
Gear ratio is varied by varying the width of pulleys.
Limited to small engines of capacity < 2litres..
Electronically controlled by sensors.