Nissan Electronically Controlled Four Speed Automatic Transmission

This paper describes the Nissan R01A model automatic transmission, focusing in particular on the basic design concept, control system and the various control techniques it incorporates. This 4-speed transmission, installed in Nissan's rear-wheel-drive vehicles, was designed from the ground up and significant construction and control mechanism improvements were made over the former conventional model. With a compact gear arrangement consisting of two sets of planetary gears, this transmission features a new electro-hydraulic control system which not only provides optimum shifting and lock-up points, but also modulates the hydraulic pressure electronically to achieve superior shift quality. Control over the transmission is integrated with engine control to deliver improved driveability and better fuel economy. Different transmission variations have been developed to create a versatile lineup for rear-wheel-drive vehicles. A high torque capacity version, built with the same basic construction and control system as the standard model, is available along with a PTO-equipped version intended for commercial vehicle application. This paper also presents a brief introduction of this R01A series.