Automatic Transmission Torque Down Control During Inertia Phase
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Solution Overview
Problem
Existing automatic transmission speed change control methods face challenges in completing speed changes within a short time period due to insufficient torque down amount during upshifting, especially when the accelerator is stepped down, leading to potential stagnation or retrogression of the speed change operation.
Innovation Solution
A speed change control device for automatic transmissions that includes an inertia phase final period decision unit, a return control unit, a speed change progression decision unit, and a resumption control unit, which resumes torque down control if the speed change is not progressing, ensuring the required torque down amount is maintained, and an elapsed time calculation unit to continue torque down control for a predetermined time period.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If torque down control is performed by gradually decreasing the torque down amount during return control, then the speed change process becomes smoother and more comfortable, but the actual torque down amount becomes deficient when the accelerator is stepped down, causing stagnation or retrogression of speed change operation
Solution Approach 1:
The control device monitors the actual torque down amount during return control and compares it with the required torque down amount. When the accelerator is stepped down and the actual torque down amount becomes deficient, the system detects this condition and adjusts the torque down amount accordingly to maintain adequate speed change control.
Solution Approach 2:
The torque down amount is dynamically adjusted during return control based on accelerator operation. The system transitions from a fixed gradual decrease approach to a dynamic control strategy that modifies the torque down amount in real-time based on driver input and speed change progression, ensuring both smoothness and adequacy.
2Device complexity
If torque down amount is gradually decreased to zero during return control, then the control complexity is reduced and the process is simplified, but the time period until speed changing is completed becomes drawn out due to insufficient torque down amount
Solution Approach 1:
The control system implements periodic monitoring of speed change progression during return control. When stagnation or retrogression is detected, the system periodically adjusts the torque down amount to ensure adequate speed change control, balancing simplicity with time efficiency.
Solution Approach 2:
The control device automatically monitors its own operation and self-adjusts the torque down amount when deficiencies are detected. The system uses built-in sensors and control logic to detect insufficient torque down amount and autonomously corrects the issue without requiring external intervention, maintaining both simplicity and effectiveness.
Data Source
AI summary
Since there are provided an inertia phase final period decision unit which decides whether or not the final period of the inertia phase of a speed change is currently occurring, a return control unit which, taking an affirmative result of this decision as a starting condition, performs return control in order to return from the torque down control by gradually decreasing the amount of decrease of output torque, a speed change progression decision unit which, during this return control from the torque down control, decides whether or not the speed change is progressing, and a resumption control unit which resumes the torque down control if the result of this decision is negative, accordingly, during the return control from the torque down control, by resuming the torque down control when there is no progression with the speed change.