Hydraulisches Steuersystem für Automatikgetriebe

摘要

A hydraulic control system for an automatic transmission includes a 3-4 shift valve that outputs a source pressure through a first path for shift speeds lower than a fourth shift speed established by directly connecting an input shaft with an output shaft of the automatic transmission, i.e., third shift speed. The hydraulic control system further includes a clutch apply control valve that outputs a source pressure through a second path at a shift speed higher than the fourth shift speed, i.e., fifth speed. The 3-4 shift valve and the clutch apply control valve serve to interrupt supply of the source pressure through the first path and the second path, respectively, in the fourth speed or the lock-up stage.