Vehicle Transmission Clutch Torque Control via Feedforward and Feedback
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current clutch engagement strategies in automatic transmissions face delays and variations due to insufficient detection of the oncoming clutch's starting torque capacity, leading to delayed activation of feedback control and potential operator dissatisfaction.
Innovation Solution
A method involving a controller that increases the oncoming clutch torque via a feedforward command and adjusts it via feedback to compensate for deviations, using torque converter model equations to estimate and adjust torque based on differences between desired and estimated end of engagement torques and turbine accelerations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional clutch engagement strategies are used, then the system structure remains simple, but delays and variations occur due to insufficient detection of starting torque capacity
Solution Approach 1:
The patent implements feedback control by continuously monitoring clutch torque and comparing it against desired torque values. The controller adjusts the clutch command based on the difference between actual and desired torque, enabling precise detection of starting torque capacity and elimination of engagement delays and variations.
Solution Approach 2:
The patent applies feedforward control by pre-calculating the desired clutch torque trajectory based on turbine acceleration requirements. This preliminary action allows the system to proactively adjust clutch torque before engagement issues occur, improving detection precision without adding complex reactive control mechanisms.
2Ease of operation
If feedback control is activated later, then the control system remains simpler, but operator dissatisfaction increases due to delayed response
Solution Approach 1:
The system activates feedback control at the optimal moment by detecting when clutch torque reaches a predetermined threshold during engagement. This preliminary detection ensures feedback control is engaged promptly without unnecessary delays, improving operator satisfaction while maintaining efficient control activation timing.
Solution Approach 2:
The patent replaces mechanical torque sensing mechanisms with electronic torque estimation based on turbine acceleration measurements. This substitution enables timely detection of clutch torque capacity and prompt activation of feedback control, reducing delays while maintaining system simplicity.
3Stability of the object's composition
If torque variations are not compensated, then the control algorithm remains simpler, but engagement smoothness deteriorates
Solution Approach 1:
The patent uses feedback control to continuously monitor clutch torque and detect variations from the desired torque trajectory. When torque deviations are detected, the controller adjusts the clutch command in real-time to compensate for variations, ensuring smooth engagement while using a relatively simple control algorithm that builds upon conventional strategies.
Data Source
AI summary
A vehicle includes a transmission having a torque converter, an oncoming clutch, and a controller. The controller is programmed to, in response to a torque of the oncoming clutch exceeding an estimated average by a threshold during an engagement, increase the torque of the oncoming clutch via a feedforward command and adjust the torque of the oncoming clutch via a feedback command to compensate for deviations in the torque generated by the feedforward command during the engagement.