Transmission Technologies

Automated Manual/Dual Clutch Transmissions
Continuously Variable Transmission
Manual 6-Speed Transmissions
6, 7, and 8 Speed Automatic Transmissions

Automated manual/dual clutch transmissions are two similar transmission types.  An automated manual transmission is a manual transmission with no clutch.  Shifts are controlled electrically and hydraulically.  Dual clutch transmissions contain two separate clutches and are like a manual transmission, but the vehicle controls shifting and launch functions.  A separate clutch is used for the even number gears and the other clutch is used for the odd numbered gears.  This allows for faster and smoother shifting.

Potential fuel economy benefit – [4-8%]

A continuously variable transmission (CVT) uses V-shaped pulleys connected by a metal belt rather than gears to provide the ratios for operation.  Unlike manual and automatic transmissions with fixed transmission ratios, CVTs can provide fully variable transmission ratios with an infinite number of gears, so the engine can operate at higher efficiency.

Potential fuel economy benefit – [4-8%]

Manual 6-speed transmissions offer an additional gear, usually a higher overdrive ratio, than a 5-speed manual transmission.  This improves efficiency by reducing engine revolutions per minute when on the highway.

Six, seven and eight speed automatic transmissions are becoming available.  These transmissions have gear ratio spacing optimized for a broader range of operating conditions and better efficiency.

Potential fuel economy benefit – [3-5%]

The information contained on this website is intended as practical guidance coupled with examples of auto fuel economy policies and approaches in use around the world. It is not a complete collection of all national examples, nor does it track national and global progress on improving auto fuel economy. It is a work in progress and is updated regularly.This website does not support IE 5 and below.


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