Vehicle Gear Shift Control Device Torque Adaptation
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Solution Overview
Problem
Existing gear shift control techniques for automatic transmissions fail to effectively manage a decrease in input torque during gear shifts, leading to excessive correction in engagement capacity and resulting in shock and a push-out feeling, especially when the accelerator is returned.
Innovation Solution
A control device and method that dynamically updates the target gear shift characteristic value based on changes in input torque, allowing for stable gear shift control by adjusting the gear shift control parameters in response to decreasing torque levels, thereby preventing shock occurrence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If feedforward control is performed at gear shift start time using target power source torque, then gear shift shock is reduced, but the system cannot cope with decrease in input torque during gear shift
Solution Approach 1:
The control system dynamically updates the target gear shift characteristic value during the gear shift process based on actual input torque conditions. When input torque decreases below a predetermined threshold, the system adjusts the target value to match torque conditions at the updated time, enabling adaptive response to changing torque conditions while maintaining shock suppression capability
Solution Approach 2:
The system monitors actual input torque during gear shift and uses this feedback to determine whether to update the target gear shift characteristic value. This closed-loop approach allows the system to respond to torque decreases by comparing actual torque conditions against predetermined thresholds and adjusting control parameters accordingly
2Ease of operation
If engagement capacity of friction elements is corrected using feedforward control at gear shift start, then gear shift smoothness is improved, but excessive correction occurs when input torque decreases during gear shift
Solution Approach 1:
The engagement capacity control transitions from static feedforward correction based on initial torque to dynamic correction that updates the target gear shift characteristic value during the shift process. This allows the correction amount to adapt to actual torque conditions, preventing excessive correction when torque decreases while maintaining smoothness
Solution Approach 2:
The system changes the target gear shift characteristic value parameter from a fixed initial value to a dynamically updated value that reflects current input torque conditions. This parameter update mechanism ensures that engagement capacity correction remains precise under varying torque conditions by adjusting the target value to match actual torque at the updating time
Data Source
AI summary
An electronic control unit updates a target gear shift characteristic value to a target gear shift characteristic value which is set at a gear shift start time with a first predetermined torque based on the first predetermined torque and performs gear shift control from a degree of progress in gear shift based on the updated target gear shift characteristic value, when an input torque becomes equal to or less than the first predetermined torque due to an accelerator returning operation or the like during a gear shift (during a power-on upshift). Accordingly, it is possible to perform stable gear shift control to cope with a decrease in input torque during the gear shift and to suppress occurrence of a shock.