Double Clutch Starting Method for Smooth Torque Transitions
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Solution Overview
Problem
Existing starting methods for internal combustion engines with double clutch transmissions do not provide optimal driving comfort and flexibility in gear changes, often resulting in tractive force dips and mechanical wear during shifting processes.
Innovation Solution
A method involving a double clutch system where the first gear is engaged and activated at the start, while the second gear is engaged but not activated, with continuous comparison to a reference variable, causing the first clutch to open and the second clutch to close, resulting in a constant torque sum that is less than or equal to the engine torque, allowing smooth transitions from high to low transmission ratios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single clutch is used for gear changes, then the structure is simpler, but tractive force dips occur during shifting and driving comfort deteriorates
Solution Approach 1:
The clutch system is segmented into two independent clutches (first clutch and second clutch), each controlling a different gear. This allows one clutch to be engaged while the other is disengaged, enabling smooth gear transitions without tractive force dips, thereby improving driving comfort while maintaining manageable structural complexity
2Ease of operation
If gear shifting is automated, then driving comfort is improved, but flexibility in starting behavior is reduced
Solution Approach 1:
The control system dynamically adjusts the actuation of the two clutches based on desired starting behavior. For comfortable starting, the first clutch is gradually opened while the second is closed; for sporty starting, the switching is more abrupt. This dynamic control provides both automated comfort and behavioral flexibility
3Productivity
If rapid gear switching is performed, then productivity is improved, but mechanical wear increases
Solution Approach 1:
The second gear is pre-engaged with the second clutch before the first clutch is fully disengaged. This preliminary action ensures that the transmission path is already prepared, allowing rapid switching without mechanical冲击, thus improving shifting speed while preventing increased mechanical wear
4Device complexity
If torque is not maintained constant during shifting, then device complexity is reduced, but tractive force dips occur
Solution Approach 1:
The control system continuously monitors the torque output and adjusts the clutch actuation to maintain constant torque during the transition. This feedback control ensures smooth tractive force delivery without dips, improving driving comfort while keeping the control system complexity manageable
Data Source
AI summary
A method implements a starting process for an internal combustion engine which has a drive unit and a transmission with at least two transmission input shafts and a multiple clutch device, in particular a double clutch device. During the starting process, the first gear is engaged in a first clutch of the multiple clutch device and is activated, while the second gear speed is engaged in a second clutch of the multiple clutch device but not activated. During the starting process, a current velocity is compared with a predefinable reference velocity, and when the reference velocity is reached a control unit causes the first clutch to be opened and thus causes the first gear to be deactivated while, in parallel with this, the second clutch is closed and the second gear is thus activated.