Clutch Torque Trajectory Correction to Provide Torque Hole Filling during a Ratio Upshift

摘要

A control system and method for controlling a multiple gear ratio automatic transmission in a powertrain for an automatic transmission having pressure activated friction torque elements to effect gear ratio upshifts. The friction torque elements are synchronously engaged and released during a torque phase of an upshift event as torque from a torque source is increased while allowing the off-going friction elements to slip, followed by an inertia phase during which torque from a torque source is modulated. A perceptible transmission output torque reduction during an upshift is avoided. Measured torque values are used during a torque phase of the upshift to correct an estimated oncoming friction element target torque so that transient torque disturbances at an oncoming clutch are avoided and torque transients at the output shaft are reduced.

主权项

1. A powertrain having a torque input shaft and a multiple ratio power transmission mechanism with an oncoming torque transmitting friction element and an off-going torque transmitting friction element for effecting ratio upshifts during torque delivery to a torque output shaft, and a shift controller configured for:
increasing torque input at a controlled rate during a torque phase of a ratio upshift; estimating oncoming friction element torque during the torque phase of the upshift; controlling torque input to achieve a desired off-going friction element slip; measuring actual friction element torque for the torque transmitting friction elements of the transmission; and correcting estimated oncoming friction element torque using the measured torque whereby a target torque for the oncoming friction element is achieved with minimal torque transients during the torque phase.