High Efficiency 6-speed Automatic Transmission

A new 6-speed automatic transmission (AT) has been developed with the aim of enhancing fuel economy, raising efficiency, and achieving greater compactness. The unit was built on a parallel-shaft structure similar to the previous Honda AT, which has high torque transmission efficiency. The new AT was given more gear speeds and the ability to handle higher input torque from the engine. On the one hand, bolt structure for shaft tightening was implemented, the forward-reverse shift mechanism was placed on the input shaft and common gear trains are provided. As a result of these and other measures, the total length of the new transmission is 18 mm shorter than the previous model 5-speed AT. A multi-plate lock-up clutch (LC) structure with a separate chamber in the torque converter was also adopted so that the lock-up torque capacity could be increased and the LC control range expanded. In combination with decreased friction loss torque and improved transmission efficiency by the new hydraulic control system, lubrication oil management and improvement of the gear contacts, this new configuration achieves a 5% or greater increase in fuel economy over that of the previous model 5-speed AT, while realizing greater power and driving performance with enhanced direct feeling.