Dynamic Learning Control for Automatic Transmission Reliability
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Summary
Problems
The increasing demand for improved fuel economy through idling stop techniques reduces opportunities to learn the engagement start pressure of friction engagement elements in automatic transmissions, necessitating a method to ensure learning occasions while the vehicle is running.
Innovation solutions
An automatic transmission system that includes a learning control mechanism to cause the second friction engagement element to slip while running in the second gear position, allowing the learning of the engagement start pressure of the first friction engagement element based on differential rotation changes, enabling accurate determination of the engagement start pressure even when the vehicle is in motion.
TRIZ Analysis
Specific contradictions:
General conflict description:
Principle concept:
If idling stop techniques are adopted to improve fuel economy, then fuel consumption is reduced, but opportunities to learn engagement start pressure of friction engagement elements are reduced
Why choose this principle:
The patent transitions the learning control from a static condition (vehicle stopped) to a dynamic condition (vehicle running). The learning control is now executed during vehicle operation by causing a friction engagement element to slip while the vehicle is running, allowing engagement start pressure learning to occur dynamically during normal operation rather than requiring static idle conditions.
Principle concept:
If idling stop techniques are adopted to improve fuel economy, then fuel consumption is reduced, but opportunities to learn engagement start pressure of friction engagement elements are reduced
Why choose this principle:
The patent changes the operational parameters under which learning control is executed. Instead of learning only when the vehicle is stopped with the engine running, the system now performs learning when the vehicle is running at various speeds. The control unit adjusts instructional pressure to cause slipping while maintaining vehicle motion, fundamentally changing the operational state parameters for learning execution.
Application Domain
Data Source
AI summary:
An automatic transmission system that includes a learning control mechanism to cause the second friction engagement element to slip while running in the second gear position, allowing the learning of the engagement start pressure of the first friction engagement element based on differential rotation changes, enabling accurate determination of the engagement start pressure even when the vehicle is in motion.
Abstract
The automatic transmission includes a first friction engagement element which is engaged when a first gear position is realized and disengaged when a second gear position is realized, a second friction engagement element which is engaged when the second gear position is realized and disengaged when the first gear position is realized, and a controller. The controller causes the second friction engagement element to slip by decreasing an instructional pressure for the second friction engagement element while running in the second gear position, and learns an engagement start pressure of the first friction engagement element based on a change in a differential rotation of the second friction engagement element, or in a parameter that changes in accordance with the differential rotation, at a time when an instructional pressure for the first friction engagement element is increased during the slip.