Power downshift clutch control

摘要

A method of controlling clutches in a multi-speed transmission includes beginning a current shift from a starting gear to an initial target gear, and determining whether the current shift is a downshift. The method determines jump-stage eligibility of a first clutch. Determining jump-stage eligibility includes determining whether the first clutch is a holding clutch for the current shift, and determining whether the first clutch is an off-going clutch for a legal shift from the initial starting gear to an adjusted target gear having a higher speed ratio than the initial starting gear. If the first clutch is not jump-stage eligible, the method maintains pressure of the first clutch at a current pressure. If the first clutch is jump-stage eligible, the method reduces the pressure of the first clutch from the current pressure to a staging pressure, which is greater than a slipping pressure.

主权项

1. A method of controlling clutches in a multi-speed transmission, comprising:
beginning a current shift, wherein the current shift changes the transmission from a starting gear to an initial target gear; determining whether the current shift is a downshift, such that the initial target gear has a higher speed ratio than the starting gear; determining jump-stage eligibility of a first clutch, including:
determining whether the first clutch is a holding clutch for the current shift; anddetermining whether the first clutch is an off-going clutch for a legal shift from the starting gear to an adjusted target gear, which has a higher speed ratio than the starting gear; if the first clutch is not jump-stage eligible, maintaining pressure of the first clutch at a current pressure; and if the first clutch is jump-stage eligible, reducing the pressure of the first clutch from the current pressure to a staging pressure, wherein the staging pressure is greater than a slipping pressure.