Automatic Transmission Clutch Fill Volume Determination
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Solution Overview
Problem
Manufacturing variations in automatic transmission components lead to deviations in hydraulic fluid fill volumes, affecting clutch engagement and shift quality, as nominal fill volumes may not accurately represent actual fill volumes due to machining tolerances and build variations.
Innovation Solution
A method to determine the fill volume of a clutch in an automatic transmission by observing the clutch fill sequence from fluid pressure measurements, which includes identifying an initial rise, a plateau, and a final rise, and calculating the fill end time through extrapolation and derivative analysis, allowing for accurate clutch fill volume calculation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If nominal fill volumes are used for clutch control, then device complexity is reduced, but manufacturing precision is compromised due to variations from machining tolerances and build variations
Solution Approach 1:
The system performs preliminary measurement of actual clutch fill volume during manufacturing or initial operation, storing this data for later use in adaptive control. This preliminary action captures the actual fill volume affected by manufacturing variations before normal operation begins, allowing the control system to compensate for these variations without adding complexity to the core control architecture.
Solution Approach 2:
The system implements feedback by measuring actual clutch fill volume and using this information to adjust control parameters. The measured fill volume data feeds back into the control algorithm, enabling the system to adapt to manufacturing variations and maintain precise clutch engagement despite using nominal values in the base control logic.
2Reliability
If actual clutch fill volume is measured and used, then shift quality is improved, but measurement precision requirements increase
Solution Approach 1:
The system uses an intermediary measurement approach by monitoring fluid pressure changes during clutch fill rather than directly measuring fill volume. This indirect measurement through pressure sensing provides sufficient precision for adaptive control without requiring extremely precise direct volume measurement capabilities, thus maintaining reliability while reducing measurement precision requirements.
Solution Approach 2:
The system changes the measurement parameter from direct volume measurement to pressure-based indirect measurement. By monitoring pressure changes during the fill process and calculating fill volume from these pressure measurements, the system achieves adequate measurement precision without requiring high-precision direct volume sensing equipment.
3Reliability
If adaptive clutch control is implemented, then shift quality is improved, but device complexity increases
Solution Approach 1:
The system performs preliminary measurement and storage of actual clutch fill volume data during manufacturing or initial operation. This preliminary action captures the specific characteristics of each clutch assembly, allowing the adaptive control algorithm to use pre-acquired data rather than requiring complex real-time measurement and calculation systems during normal operation.
Solution Approach 2:
The system implements feedback by using measured fill volume data to adjust control parameters adaptively. The feedback mechanism allows the control system to compensate for manufacturing variations and optimize shift quality without requiring fundamentally complex control architecture, as the adaptation is based on straightforward comparison between nominal and actual fill volumes.
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 method provides accurate clutch fill volume data, enabling improved shift quality and adaptive clutch control by accounting for manufacturing variations, ensuring precise fluid application and engagement, thereby enhancing the performance of automatic transmissions.
Implementation Method 1
a clutch fill sequence is observed from measurement of fluid pressure applied to the clutch
Data Source
AI summary
A method of determining a fill volume of a clutch of an automatic transmission. A clutch fill sequence is observed from measurement of fluid pressure applied to the clutch, wherein the sequence may include a initial rise, a plateau, and a final rise. A fill end time may be identified as corresponding to an intersection of a forward extrapolated portion of the plateau and a backward extrapolated portion of the final rise.