Predictive Torque Control for Change-of-Mind Shift Maneuvers
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Solution Overview
Problem
Automatic transmissions face challenges in smoothly executing change-of-mind shift maneuvers, where a driver initiates a new gear shift before completing a previous one, leading to potential delays and noise due to abrupt torque management changes.
Innovation Solution
A controller with predictive logic and torque management modules calculates and executes shift control values to manage torque and clutch pressure, predicting acceleration profiles and optimizing shifts during change-of-mind maneuvers, such as skip-at-sync quick shifts and power downshifts, by merging torque control strategies and using lumped inertia models to reduce delay and noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a driver initiates a new gear shift before completing a previous one (change-of-mind maneuver), then the driver can quickly respond to changing driving conditions, but the transmission experiences delays and noise due to abrupt torque management changes
Solution Approach 1:
The controller predicts the acceleration profile of the turbine for the next-requested shift in advance, before the shift is actually executed. This predictive approach allows the system to prepare torque management strategies ahead of time, smoothing out the transitions and eliminating abrupt changes that cause noise and delay during change-of-mind maneuvers
Solution Approach 2:
The system dynamically adjusts torque management based on predicted acceleration profiles and real-time shift status. By merging torque control of the first shift with the subsequent second shift in a dynamic, adaptive manner, the controller optimizes torque delivery throughout the change-of-mind maneuver, reducing harmful effects while maintaining quick response
Data Source
AI summary
A system includes a torque converter having a turbine, a transmission having friction clutches and an input member connected to the turbine, and a controller. The controller is programmed to control a change-of-mind shift maneuver of the transmission. By executing a method, the controller detects the change-of-mind shift maneuver, predicts an acceleration profile of the turbine for a next-requested shift of the detected shift maneuver as a function of a calibrated desired shift time and an output speed of the transmission, calculates a shift control value for a next-requested shift of the shift maneuver using the predicted acceleration profile, and executes the next-requested shift via the clutches using the calculated shift control value. The shift maneuver may be a skip-at-sync quick shift-to-quick shift or power downshift-to-power downshift. The shift value may be a clutch pressure for an offgoing holding clutch or a torque management level from an engine.