Automatic Gearbox Shifting Element Control for Safe Disengagement
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Solution Overview
Problem
Current automatic transmissions with multiple gears lack methods for safely and gently interrupting torque or power transmission when disengaging from a forward or reverse gear, leading to potential mechanical issues and safety concerns.
Innovation Solution
The method involves fully opening at least one shifting element in the automatic transmission during gear disengagement, with specific time intervals for partial and complete opening of switching elements to ensure safe and gentle power transmission interruption, utilizing four alternative strategies based on safety and reaction time requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple shifting elements are closed in forward or reverse gear for torque transmission, then the transmission can achieve multiple gears with reliable power transmission, but the gear disengagement process becomes complex and potentially unsafe without proper control methods
Solution Approach 1:
The gear disengagement process is segmented into distinct phases: a first time interval where a first switching element is partially opened in a modulating manner to begin interrupting torque transmission, and a subsequent second time interval where at least one second switching element is fully opened to complete the disengagement. This segmentation allows complex multi-element disengagement to be controlled through structured temporal phases, ensuring safety and reliability while managing the complexity of coordinating multiple shifting elements.
2Reliability
If all shifting elements are fully opened during gear disengagement, then the torque transmission is completely interrupted, but the transition may cause mechanical shock or safety issues
Solution Approach 1:
The invention applies beforehand cushioning by partially opening the first switching element in a modulating manner during the first time interval before the second switching element is fully opened. This gradual, staged approach to opening switching elements cushions the interruption of torque transmission, preventing sudden mechanical shocks that would occur if all elements were opened simultaneously, while still achieving complete torque interruption for safe gear disengagement.
3Productivity
If gear disengagement is performed quickly to improve response time, then productivity increases, but safety and gentleness of torque interruption cannot be ensured
Solution Approach 1:
The gear disengagement process employs periodic action through its structured two-interval timing sequence. The first time interval performs the initial partial opening of the first switching element in a modulating manner, and the second time interval completes the disengagement by fully opening the second switching element. This periodic, phased approach ensures that torque transmission is interrupted safely and gently while maintaining efficient gear shifting performance, resolving the conflict between speed and safety.
Data Source
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AI summary
The invention relates to a method for operating an automatic gearbox of a motor vehicle, in particular a variable automatic gearbox. Said automatic gearbox comprises at least five shifting elements. At least three shifting elements are closed for transmitting torque and/or force in a forward gear and in a reverse gear. According to the invention, when a gear is selected to shift the automatic gearbox from a forward gear or a reverse gear into a neutral position, at least one of the shifting elements of the automatic gearbox, which is closed in the respective forward gear and/or reverse gear, is completely opened.