Dual-Clutch Transmission Parking Lock With Fallback Gear Engagement
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Solution Overview
Problem
Existing dual-clutch transmission systems lack an effective method to implement a reliable parking lock, especially when the engagement of specific gears is prevented due to geometric positions or other operational failures, leading to potential vehicle rolling away on slopes.
Innovation Solution
A method that shifts the dual-clutch transmission into a parking lock state by engaging a first gear and, upon determining the second gear is not engaged, selecting and engaging a third gear simultaneously with the first gear, while both clutches are opened, to achieve a mechanical parking lock without additional components, ensuring the vehicle is secured against rolling away.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the second gear engagement is attempted in the conventional parking lock method, then the parking lock can be engaged under normal conditions, but the method fails when the second gear cannot be engaged due to geometric positions or operational failures
Solution Approach 1:
The control unit attempts to engage the second gear as a preliminary action before finalizing the parking lock state. If this preliminary action fails (detected by the engagement detection unit), the system has already prepared alternative actions (engaging first and third gears simultaneously) to ensure the parking lock can still be achieved.
Solution Approach 2:
Instead of relying on a single gear engagement (second gear) to achieve parking lock, the invention inverts the approach by using simultaneous engagement of multiple gears (first and third gears) as the fallback mechanism. This inversion ensures that even if the conventional single-gear approach fails, the parking lock function is still achieved through an alternative gear configuration.
2Device complexity
If a single gear (second gear) is used for parking lock engagement, then the mechanism is simple, but it cannot provide reliable locking when that specific gear engagement is prevented
Solution Approach 1:
The invention merges multiple gear engagement mechanisms (first gear and third gear) into a single coordinated action for achieving the parking lock state. The control unit simultaneously engages both gears, and the engagement detection unit monitors both engagements, creating a combined mechanism that provides redundancy and ensures reliable locking even if one gear engagement fails.
3Ease of operation
If the conventional parking lock method is used, then it works under normal operating conditions, but it cannot handle cases where geometric positions prevent second gear engagement
Solution Approach 1:
The engagement detection unit provides feedback to the control unit about the status of gear engagement. When the feedback indicates that the second gear engagement failed (due to geometric positions or other constraints), the control unit automatically adjusts the operation by engaging the first and third gears simultaneously, ensuring the parking lock is still achieved despite the geometric constraints.
Data Source
AI summary
A method for operating a dual-clutch transmission having a first partial transmission, a second partial transmission, a first clutch assigned to the first partial transmission, and a second clutch assigned to the second partial transmission, in which the dual-clutch transmission is shifted into a parking lock state. The dual-clutch transmission is shifted into the parking lock state by the following steps: while a first gear of one of the partial transmissions is engaged: carrying out an engagement process provided for engaging a second gear of the one partial transmission; determining that the second gear is not engaged despite the engagement process being carried out; selecting a third gear of the dual-clutch transmission different from the first gear and from the second gear; and engaging the selected third gear such that in the park lock condition, the first gear and the third gear are at least temporarily engaged simultaneously.