Automatic Transmission Torque Control Interpolation
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Solution Overview
Problem
Existing automatic transmission control systems face issues with setting unintended torque capacities during gear shifts, leading to suboptimal gear shift quality due to actual transmission gear ratios falling outside the calculated range, which can result in either slow shifts or shift shocks.
Innovation Solution
An automatic transmission control apparatus that uses a sensor to obtain the actual transmission gear ratio and a controller to perform shift control operations, including interpolation-based torque capacity settings using reference gear ratios, ensuring the torque capacity remains within the desired range by adjusting settings based on the actual gear ratio's position relative to the reference points.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If transmission gear ratio interpolation operation is performed using two reference transmission gear ratios closer to the actual transmission gear ratio, then the torque capacity calculation precision is improved, but the device complexity increases due to additional judgment operations required
Solution Approach 1:
The patent divides the interpolation operation into two distinct segments: (1) judgment operation to determine whether the actual transmission gear ratio falls within the transmission gear ratio interval, and (2) interpolation operation to calculate the desired torque capacity. This segmentation allows the system to select the appropriate operation based on the ratio position, improving precision without unnecessarily increasing complexity in all cases.
Solution Approach 2:
The control apparatus dynamically selects the operation mode based on the position of the actual transmission gear ratio. When the ratio is outside the interval, only judgment is performed; when inside the interval, full interpolation is performed. This dynamic adaptation optimizes the balance between precision and complexity based on real-time operating conditions.
2Speed
If the actual transmission gear ratio falls outside the transmission gear ratio interval, then the gear shift speed may be improved, but the torque capacity may deviate from the desired range causing shift quality deterioration
Solution Approach 1:
The patent applies preliminary anti-action by performing a judgment operation before the interpolation operation to prevent torque capacity deviation. When the actual transmission gear ratio is determined to be outside the transmission gear ratio interval, the system anticipates potential torque capacity errors and takes preventive action by adjusting the interpolation approach, thereby maintaining torque capacity accuracy even during fast gear shifts.
Solution Approach 2:
The system uses feedback from the position of the actual transmission gear ratio relative to the transmission gear ratio interval to adjust the torque capacity calculation. This feedback mechanism ensures that the desired torque capacity is accurately determined regardless of whether the actual ratio is inside or outside the interval, maintaining reliability during high-speed shifts.
3Adaptability or versatility
If transmission gear ratio interpolation operation is performed when actual gear ratio is outside the interval, then the adaptability is improved, but the torque capacity may be set at unintended values affecting shift quality
Solution Approach 1:
The patent performs a preliminary judgment operation to determine the position of the actual transmission gear ratio before conducting the interpolation operation. This preliminary action allows the system to adapt to out-of-range ratios while maintaining precision by selecting the appropriate reference transmission gear ratios for interpolation based on the judgment result, ensuring accurate torque capacity setting regardless of the actual ratio position.
Data Source
AI summary
During control of a shift of a first friction engagement element from an engaged state into a disengaged state and a shift of a second friction engagement element from a disengaged state into an engaged state for a gear shift to a first target gear from a second target gear, a desired torque capacity of the first friction engagement element is set based on an actual transmission gear ratio by interpolation from values of the desired torque capacity corresponding to at least first and second reference transmission gear ratios, wherein the first reference transmission gear ratio is a transmission gear ratio at start of an inertia phase of the shift control. When the first reference transmission gear ratio is between the actual transmission gear ratio and the second reference transmission gear ratio, the desired torque capacity is set to the value corresponding to the first reference transmission gear ratio.