The CVT transmission, or Continuously Variable Transmission, is a clutchless semi-automatic transmission that can be operated by paddle-shifters mounted on the steering wheel. It always works at the correct gear ratio to allow the engine optimum performance.

Background

CVT transmissions were pioneered by the Dutch company DAF, but the technology was not widely used until around 2000, according to carkeys.co.uk.

Concept

The Continuously Variable Transmission changes gears without a clutch, using an infinite number of gear ratios to provide better fuel efficiency, according to carkeys.co.uk.

RPM Efficiency

Better gas mileage is achieved because the engine is operated by the transmission, with more efficient revolutions per minute at different speeds.

Twin Uses

The MG TF, once a British-made roadster now owned by a Chinese company, produces the 120 StepSpeed that allows the driver to slip the shift lever from automatic to "Sport" mode to manually shift the transmission with steering-wheel-mounted paddle-shifters.

Technology

The CVT does not use the traditional torque converter, but a large rubber/steel V-shape adjustable belt with a variable width that changes the gear ratio, according to carkeys.co.uk.

Engine Versatility

With an infinite variable gear ratio, which is not possible with the manual or automatic transmission, the engine, not the driver or torque converter, chooses the best ratio for the conditions on the road.

Source:

CVT Transmission Background

MG TF 120 StepSpeed CVT Transmission

Nissan's CVT Transmission