Multi-Clutch Transmission Control via Central Synchronizer
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Solution Overview
Problem
Dual-clutch transmissions in vehicles often experience delays and inefficiencies due to tooth-tooth situations during gear shifting, where the relative movement of engaging parts can lead to a temporary lockup, requiring time-consuming actuation to resolve.
Innovation Solution
The method employs a central synchronizer that can switch between two active states to synchronize and desynchronize the speed of tooth clutch members, allowing for immediate engagement by creating a slight speed difference, thus preventing tooth-tooth situations and ensuring smooth gear shifts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the open input clutch is actuated to create relative movement between engaging parts, then the tooth-tooth situation is resolved, but the gear shifting is delayed
Solution Approach 1:
The patent applies preliminary action by pre-selecting the next gear before the current gear is fully disengaged. The synchronization step is performed in advance during the transition period, preparing the tooth clutch for immediate engagement without requiring additional time-consuming actuation of the input clutch. This resolves the tooth-tooth situation proactively rather than reactively.
Solution Approach 2:
The patent introduces a central synchronizer as an intermediary mechanism that independently adjusts the speed of the input shaft or counter shaft. This synchronizer acts as a mediator between the driving and driven elements, creating the necessary speed difference to prevent tooth-tooth locking without requiring actuation of the input clutch, thereby eliminating the delay.
2Ease of operation
If the input clutch is actuated to resolve tooth-tooth situation, then engagement is enabled, but the operation becomes more complex
Solution Approach 1:
The patent segments the synchronization function from the clutch actuation system by introducing a separate central synchronizer. This divides the overall gear shifting function into independent components: the input clutch remains responsible for main engagement control, while the central synchronizer handles speed matching. This segmentation simplifies the operation of each component and reduces the complexity of coordinating them.
Solution Approach 2:
The central synchronizer serves as an intermediary that handles the complex speed synchronization task independently. By offloading this function from the input clutch control system, the patent simplifies the overall operation - the input clutch only needs to manage engagement/disengagement while the synchronizer automatically manages speed matching to prevent tooth-tooth situations.
3Reliability
If synchronization is performed before gear engagement, then tooth-tooth situations are prevented, but the gear shifting process is extended
Solution Approach 1:
The patent performs synchronization as a preliminary action during the gear pre-selection phase, before the tooth clutch engagement is initiated. By preparing the speed match in advance during the transition period when the current gear is still engaged, the patent ensures that when engagement occurs, the teeth are already properly aligned, preventing locking without extending the actual engagement process.
Solution Approach 2:
The patent maintains continuous useful action by overlapping the synchronization process with the gear transition period. The central synchronizer operates continuously to adjust speeds during the entire transition, ensuring that synchronization is completed seamlessly as part of the gear shifting process rather than as a separate step, thereby preventing extension of the overall shifting duration.
Data Source
AI summary
A method for controlling a multi-clutch transmission of a vehicle includes activating the central synchronizer to the first active state, such that the speed of a first member of a tooth clutch, attempting to engage the tooth clutch to be engaged, and if the tooth clutch to be engaged is determined not to be fully engaged a predetermined period of time after an initiation of an engagement, the following steps are performed: activating the central synchronizer to the second active state such that the speeds of the two members of the tooth clutch to be engaged are slightly unsynchronized, and engaging the tooth clutch to be engaged.