Transmission Control Apparatus Neutral State Reacceleration
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Solution Overview
Problem
Existing automatic transmission control systems fail to ensure quick and efficient reacceleration when the transmission is brought into a neutral state during traveling, as they do not adequately prepare for changes in vehicle speed and shift speed, leading to suboptimal fuel economy and reacceleration response.
Innovation Solution
A control apparatus and method that dynamically adjust the engagement of engagement elements to quickly attain target shift speeds by engaging at least one element and disengaging the remainder, allowing for immediate reacceleration by engaging the necessary elements upon reacceleration, and utilizing common engagement elements to reduce the need for clutch changes during shifts in vehicle speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the transmission is brought into neutral state during traveling by disengaging all engagement elements, then fuel economy is improved and vibrations are prevented, but reacceleration response deteriorates due to lack of preparation for clutch engagement
Solution Approach 1:
The patent applies preliminary action by maintaining at least one engagement element in an engaged state even when the transmission is in neutral state. This pre-prepared engagement element is ready to quickly form the target shift speed when reacceleration is needed, eliminating the delay that would occur if all elements were completely disengaged. This resolves the contradiction by preserving fuel economy through neutral state operation while maintaining reacceleration capability through the pre-engaged element.
Solution Approach 2:
The patent segments the engagement elements into two functional groups: those that are disengaged to achieve neutral state and fuel economy, and at least one that remains engaged to preserve reacceleration response. This segmentation allows the system to simultaneously achieve both fuel efficiency and quick reacceleration by dividing the roles of different engagement elements.
2Loss of energy
If all engagement elements are disengaged to achieve neutral state, then the transmission operates efficiently, but the complexity of controlling multiple engagement elements increases when reacceleration is required
Solution Approach 1:
The control apparatus determines in advance which engagement element should remain engaged during neutral state operation, based on predicted reacceleration needs. This preliminary determination simplifies the control logic by establishing a clear rule for maintaining one element engaged, rather than requiring complex real-time decisions about which elements to re-engage when acceleration is needed.
3Adaptability or versatility
If the target shift speed is changed during neutral state operation, then the transmission adapts to vehicle speed changes, but reacceleration cannot be ensured by merely preparing for engagement of a specific clutch
Solution Approach 1:
The patent makes the remaining engaged element universally applicable to multiple potential target shift speeds. By selecting an engagement element that can contribute to various shift speed configurations, the system ensures that regardless of which target shift speed becomes necessary during neutral state operation, the pre-engaged element can be combined with other elements to achieve the required shift speed, thereby maintaining both adaptability and reacceleration reliability.
Data Source
AI summary
A control apparatus for a transmission that form a plurality of shift speeds by engaging those of a plurality of engagement elements which need be engaged for each shift speed. The control apparatus having a target shift speed changing unit that changes a target shift speed based on a vehicle speed and a neutral control unit that, when predetermined conditions that are predetermined to bring the transmission into a neutral state are satisfied during traveling, engages at least one of the engagement elements that need be engaged to attain the target shift speed, and disengages the remainder of the engagement elements, thereby bringing the transmission into the neutral state.