CVT Pseudo Stepwise Up-Shift Control Mode Transition
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Solution Overview
Problem
Existing transmission control devices for continuously variable transmissions face challenges in harmonizing pseudo stepwise up-shift control and engine torque control, leading to shift shock when the driving mode is changed during up-shift in pseudo stepwise up-shift mode, particularly between drive and sports modes.
Innovation Solution
A transmission control device with mode-changing capabilities, featuring first and second pseudo stepwise up-shift controls for different driving modes, where the mode change is managed to maintain the slower shifting speed until the up-shift is completed in the drive mode and switches to the faster shifting speed before completion in the sports mode, ensuring harmonization between control states and minimizing shift shock.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the shift speed during up-shift in pseudo stepwise up-shift mode is set to be higher in sports mode than in drive mode to improve acceleration feeling, then the response of the shift is improved, but the torque reduction amount at start of up-shift becomes greater leading to increased shift shock
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the shift speed parameter based on the driving mode (drive mode or sports mode). In sports mode, a higher shift speed is used to improve acceleration response, while in drive mode, a lower shift speed is used to minimize shift shock. This parameter adaptation allows the system to optimize performance characteristics for different operational requirements.
Solution Approach 2:
The patent implements dynamics by making the shift control system adaptive to changing driving conditions and mode selections. The control device dynamically switches between different shift speed profiles and torque reduction strategies based on whether drive mode or sports mode is active, allowing the system to respond flexibly to different driver intentions and vehicle states.
2Adaptability or versatility
If the travelling mode is changed during the progress of up-shift in pseudo stepwise up-shift mode, then the adaptability to different driving conditions is improved, but the harmonization between pseudo stepwise up-shift control and engine torque control is disrupted causing shift shock
Solution Approach 1:
The patent applies preliminary action by detecting mode change requests before they fully take effect during an ongoing up-shift operation. When a mode change is detected, the control device preemptively adjusts the shift control parameters and torque reduction strategy to match the new mode requirements, preventing the harmonization disruption that would otherwise occur during the transition.
Solution Approach 2:
The patent implements feedback by continuously monitoring the driving mode state and using this information to adjust the pseudo stepwise up-shift control and engine torque control in real-time. When mode changes are detected during up-shift, the feedback mechanism triggers appropriate control parameter adjustments to maintain harmonization between the shift control and torque control, thereby preventing shift shock.
Data Source
AI summary
First control unit performing first pseudo stepwise up-shift control that, in first travelling mode, increases vehicle speed while performing hold of transmission ratio and up-shift by first shifting speed and reduces engine torque upon up-shift, second control unit performing second pseudo stepwise up-shift control that, in second travelling mode, increases vehicle speed while performing hold of transmission ratio and up-shift by second shifting speed and reduces engine torque upon up-shift, and third control unit controlling change of travelling mode and switch between two pseudo stepwise up-shift controls according to control states of first and second control units, are provided. When travelling mode is changed to second travelling mode during progress of up-shift in first pseudo stepwise up-shift control, third control unit maintains first pseudo stepwise up-shift control until up-shift is completed. With this, harmonization between pseudo stepwise up-shift control and engine torque control is secured, then shift shock is suppressed.