Shift flare control

摘要

The automotive drivetrain has an engine the output of which is drivingly coupled to the input of a multi-ratio transmission and provides an input speed to the transmission. The downshift releases a friction element associated with the higher ratio. An on-coming fluid pressure is increased to engage a second friction element associated with the lower ratio. The shift flare control involves releasing the first friction element to allow the engine to increase the input speed to a synchronous speed corresponding to the second friction element. The on-coming fluid pressure is increased at a predetermined rate to progressively engage the on-coming friction element. The acceleration of the engine is monitored to detect a negative acceleration indicative of a flare condition. When a flare condition is indicated, the predetermined rate of on-coming fluid pressure increase is incremented for use in subsequent downshifts.