Quest for fuel efficiency leading to more high-gear transmissions

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Vehicles with lots of gears make better use of available power, but there are trade-offs. Image: TonyAustin / Flickr / CC BY-SA

Making the most efficient use of fuel is the new name of the game in car manufacturing. At the 2011 auto show, Ford representatives confirmed that the company is researching seven- and eight-speed transmissions. These high-efficiency transmissions are already being used in BMW, Audi and Lexus vehicles.

The benefit of high-gear transmissions

Transmissions that use a high number of gears have been used in some applications for many years. Having more gears allows a machine to make more more efficient of available power, and it makes for a more adaptable transmission. Several different vehicle makers are starting to make use of this flexibility in vehicles. More gears means less fuel use and higher efficiency.

High-gear transmissions versus CVT

Continually variable transmissions, which are used in the Toyota Prius, are another tool used to achieve greater fuel efficiency. CVTs are different from multi-gear transmissions; they do not have single gears. Instead, they cycle continually through gear ratios depending on the load placed on the engine. Engines that use multiple gears tend to have slightly better pick-up and response time. While the difference for everyday drivers is relatively minimal, it is enough to be noticeable. In the high-competition arena of vehicle manufacturing, those minor differences could be enough to make or break the sale of a vehicle.

Balancing fuel efficiency and performance

Many vehicle makers are trying to use CVT and high-number gears to increase the efficiency of engines while maintaining performance. The theory is that American car buyers will not go green unless they are able to keep the high-power performance they are used to. The high number of orders for Nissan Leaf vehicles shows electric cars are growing in popularity, but trying to balance power and efficiency may not be nearly as popular as a move toward pure efficiency. As with all changes to the vehicle industry, though, it will take a long time for newer cars with improved fuel efficiency to displace the cars currently being driven.


Wikipedia – CVT

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