Automatic Transmission Gear Shift Control for Shock Reduction
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Solution Overview
Problem
Existing gear shift control apparatuses for automatic transmissions fail to effectively reduce shock at the inertia phase finish region due to unstable frictional engagement element coefficients and require extensive development and tuning hours, leading to deviations and external disturbances.
Innovation Solution
A gear shift control apparatus and method that temporarily reduces command hydraulic pressure to the second frictional engagement element when a predetermined degree of gear shift progress is reached, using a finish pressure control section to set the reduction quantity based on elapsed time and detected parameters, thereby progressively reducing hydraulic pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If stepwise hydraulic pressure reduction is applied at inertia phase finish immediate prior region, then shock reduction is achieved, but the effectiveness decreases as the phase approaches inertia phase finish
Solution Approach 1:
The patent applies dynamics by making the hydraulic pressure reduction gradient variable rather than fixed. The control system dynamically adjusts the reduction gradient based on the current phase within the inertia phase finish immediate prior region, using multiple sub-regions with different reduction rates to adapt to changing frictional characteristics as the phase progresses.
Solution Approach 2:
The patent changes the parameter of hydraulic pressure reduction gradient from a constant value to a variable value that changes according to the progression of the inertia phase. By dividing the region into multiple sub-regions and assigning different reduction gradients to each, the system optimizes shock reduction effectiveness at different stages of the phase.
2Object-affected harmful factors
If feed-forward control with optimized reduction gradient is used, then shock reduction is improved, but development man-hours and tuning man-hours increase significantly
Solution Approach 1:
The patent segments the inertia phase finish immediate prior region into multiple sub-regions based on gear ratio ranges. This segmentation allows the use of a standardized multi-region control strategy that can be applied across different transmission configurations, reducing the need for extensive custom tuning for each specific application.
Solution Approach 2:
The patent implements a dynamic control strategy that automatically adapts to different operating conditions through real-time monitoring of gear ratio and phase progression. This reduces the need for manual tuning by allowing the system to self-adjust based on detected parameters.
3Device complexity
If fixed hydraulic pressure reduction quantity is applied, then control simplicity is maintained, but shock reduction effectiveness deviates due to variations in gear ratio and input torque
Solution Approach 1:
The patent changes the hydraulic pressure reduction quantity from a fixed value to a variable value that depends on the detected gear ratio and phase progression. By using multiple sub-regions with different reduction quantities, the system maintains consistency across varying operating conditions while keeping the control logic structured and manageable.
4Measurement precision
If hydraulic pressure follows gear ratio vibrations, then pressure tracking is improved, but shock and instability increase at inertia phase finish
Solution Approach 1:
The patent applies preliminary action by proactively reducing hydraulic pressure in the inertia phase finish immediate prior region before the actual inertia phase finish occurs. This anticipatory pressure reduction prevents the system from entering the unstable frictional coefficient region, thereby avoiding shock and instability rather than reacting to them after they occur.
Solution Approach 2:
The patent implements preliminary anti-action by applying a counteracting hydraulic pressure reduction to offset the impending instability caused by frictional coefficient changes. This preemptive measure counteracts the potential harmful effects before they manifest, maintaining system stability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach effectively reduces shock at the inertia phase finish region without requiring many development or tuning man-hours, maintaining optimal hydraulic pressure reduction even with variations in gear ratio and input torque, while preventing hydraulic pressure from following gear ratio vibrations.
Implementation Method 1
a frictional engagement element which has been engaged at a gear stage prior to a gear shift and a second frictional engagement element which has been released at the gear stage prior to the gear shift
Data Source
AI summary
In gear shift control apparatus and method for an automatic transmission, a first frictional engagement element is, in turn, released, a second frictional engagement element is, in turn, engaged to perform the gear shift to another gear stage, a command hydraulic pressure to the second frictional engagement element is temporarily reduced when a parameter indicating a degree of progress of the gear shift detected during the gear shift to the other gear stage has reached to a predetermined value representing an inertia phase finish immediate prior region at a time of an inertia phase developed during a replacement gear shift, an reduction quantity of the command hydraulic pressure is set whenever a predetermined time has elapsed on a basis of the parameter detected whenever the predetermined time has elapsed in the inertia phase finish immediate prior region to progressively reduce the command hydraulic pressure.