摘要 |
<p>The disclosed control system for a CVT controls the line pressure which is applied to the secondary pulley to maintain adequate belt tension, at a level significantly lower than previously was produced. An improved throttle valve is provided, and used in this throttle-sensitive regulation of line pressure. An improved ratio valve is provided, which combines spring and fluid forces in a manner to produce the ratio-indicating fluid signal, with negligible loading on the movable sheave where the ratio change is sensed. In the ratio-changing portion of the system, the combination of a timing valve and accumulator valve cooperate in demand type downshifts to provide adequate time for oil flow into the secondary pulley chamber as the primary pulley chamber is exhausted, to keep adequate belt tension during such a downshift.</p> |