Earlier in the month, Toyota announced that it would be building a range of new engines and transmissions designed for the Toyota New Global Architecture (TNGA). Among them are new Direct Shift transmissions, an eight-speed gearbox for front-wheel drive applications and a 10-speed unit for rear-wheel drive vehicles.
The video above explains the workings of the former, which will likely be fitted to most new Toyota models from 2017. Replacing the current six-speeder in cars like the Camry, the new transmission will provide many of the benefits of a continuously variable transmission (CVT), such as keeping the engine at its most efficient speed for improved fuel economy, without the typical CVT “rubber band” feel.
An increase in gears provides a wider spread of ratios, enabling the car to cruise at high speeds at lower revs – this helps reduce fuel consumption and gives a quieter drive. There’s still a torque converter of course, which smoothens out startups and gearshifts, but on the move a lockup clutch transmits engine power directly to the transmission for a more direct driving feel and improved fuel economy.
In order to control the operation of the lockup clutch, engineers added a lockup control multiple disc clutch and a hydraulic circuit, increasing the lockup range and allowing for a driving performance which Toyota says precisely follows the driver’s will. Despite all these additions, the eight-speed ‘box is actually more compact than the six-speed unit.
The longitudinal 10-speed transmission, which supersedes the eight-speed transmission currently used on Toyota and Lexus’ rear-wheel drive vehicles, utilises many of the same advancements as the eight-speed unit, with the use of close-ratio gears optimising the range of use of each gear, particularly in the low-to-mid speed range. This gearbox is already being used in the new Lexus LC 500 coupé.