Automatic Transmission Control Device Torque Transition
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Solution Overview
Problem
Existing automatic transmission control devices experience shifting shock due to rapid changes in rotational speed and engagement torque during gear shifts, particularly when transitioning from a first shifting to a second shifting via an intermediate gear position, leading to potential slip rotation speed issues and mechanical stress.
Innovation Solution
A control device for automatic transmissions that gradually changes the engagement torque of the engagement-maintained engagement device from the required torque of the first shifting to the required torque of the second shifting, using a calculated rate of change to smooth the transition and prevent shock, by introducing a constraint condition in the gear train motion equations to manage torque allocations and control operation amounts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the shifting is executed by releasing two engagement devices and engaging two engagement devices via an intermediate gear position, then the shifting control can be achieved using a shifting model, but the required engagement torque of the engagement device engaged in the first shifting increases rapidly causing shifting shock
Solution Approach 1:
The patent applies dynamics by making the engagement torque of the engagement-maintained engagement device variable rather than fixed. The control device dynamically adjusts the engagement torque during the transition from first shifting to second shifting, allowing the torque to change gradually according to the shifting phase. This dynamic adjustment prevents rapid torque changes that cause shifting shock while maintaining effective shifting control.
Solution Approach 2:
The patent changes the parameter of engagement torque from a fixed value to a gradually varying value during the transition between shifting phases. By introducing a constraint condition that limits the rate of change of engagement torque, the system transforms the torque parameter to change smoothly rather than abruptly, thereby eliminating shifting shock while preserving shifting control functionality.
2Measurement precision
If the gear train motion equation is switched from the first shifting to the second shifting, then the shifting model can determine control operation amounts, but the rapid change in rotational speed of the engagement device causes slip rotation speed to become zero
Solution Approach 1:
The patent applies preliminary action by preparing the engagement torque of the engagement-maintained engagement device in advance before the complete transition to the second shifting. The control device starts gradually increasing the engagement torque during the transition phase, so that when the gear train motion equation switches, the rotational speed change is already moderated. This preliminary torque adjustment prevents the slip rotation speed from reaching zero and avoids shifting shock.
Solution Approach 2:
The engagement-maintained engagement device serves as an intermediary element between the first and second shifting phases. By maintaining this engagement device engaged throughout the transition and gradually changing its torque, the system creates a buffer that mediates the switch between different gear train motion equations. This intermediary torque control smooths the rotational speed transition and prevents abrupt changes that would cause slip rotation speed to become zero.
Data Source
AI summary
An automatic transmission control device is configured to execute a first shifting between a pre-shifting gear position and an intermediate gear position, and a second shifting between the intermediate gear position and a post-shifting gear position such that each of the first and second shiftings is executed by releasing one of engagement devices and engaging one of the engagement devices, and is configured, upon transition from the first shifting to the second transition, to gradually changing an engagement torque of an engagement-maintained engagement device as one of the engagement devices which is engaged upon completion of the first shifting and is maintained in the engaged state during the second shifting, such that the engagement torque of the engagement-maintained engagement device is changed gradually from a required engagement torque required upon completion of the first shifting, to a required engagement torque which is required in the second shifting.