Automatic Transmission Upshift Control via Gear Ratio Inversion Time
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional upshift control systems for automatic transmissions fail to accurately determine the cause of engine racing, leading to inaccurate shift timing and increased system size and weight due to the need for additional friction elements and parts.
Innovation Solution
An upshift control system that detects actual gear ratios and engine racing, compares target and actual gear ratio inversion times, and adjusts engagement pressures for friction elements based on determined engagement capacity variations to ensure accurate and stable shifting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If additional friction elements and parts (one-way clutch, hydraulic pressure switch) are added to detect engagement capacity, then measurement precision improves, but device complexity and weight increase
Solution Approach 1:
The patent extracts the detection function from physical sensors (hydraulic pressure switches) and mathematical models (friction coefficient calculations) and implements it through direct monitoring of engagement pressure and gear ratio inversion time. This eliminates the need for additional friction elements and complex sensing systems while maintaining accurate detection of engagement capacity variations.
Solution Approach 2:
The patent replaces mechanical detection systems (one-way clutches, hydraulic pressure switches) with an electronic control system that calculates engagement capacity based on measured parameters (engagement pressure, gear ratio inversion time). This substitution reduces mechanical complexity and part count while improving measurement precision through computational analysis.
2Reliability
If engagement pressure is increased to compensate for friction coefficient deterioration, then reliability improves, but energy consumption increases
Solution Approach 1:
The patent performs preliminary detection of engagement capacity variations by monitoring gear ratio inversion time and engagement pressure characteristics before actual shift performance degradation occurs. By identifying friction coefficient deterioration early, the system can proactively adjust engagement pressure only when necessary, rather than continuously maintaining high pressure, thus reducing energy consumption while preserving reliability.
Solution Approach 2:
The patent implements a feedback control mechanism where the control unit continuously monitors engagement pressure and gear ratio inversion time, compares actual values with target values, and adjusts engagement pressure accordingly. This closed-loop feedback ensures reliability by maintaining appropriate engagement pressure only when engagement capacity variations are detected, avoiding unnecessary energy consumption during normal operation.
Data Source
AI summary
An upshift control system for use in an automatic transmission including first and second friction elements, the upshift control system including a control unit that determines variation in an engagement capacity of the first friction element or an engagement capacity of the second friction element on the basis of combination of occurrence or non-occurrence of engine racing and compared lengths between a first time that elapses from output of a shift command to a start of an inertia phase and a second time that elapses from the out output of a shift command to a start of change in an actual gear ratio toward a target gear ratio to be achieved after the shifting, and performs a learning correction of a command pressure for the first friction element or a command pressure for the second friction element on the basis of the determination result.