Hybrid Drive Control Unit for Seamless Electric Shifting
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Solution Overview
Problem
In hybrid drives with a double clutch transmission, attaching the electric machine to only one sub-transmission limits its usage for purely electric driving, as it restricts the utilization of all gears and causes torque interruptions during shifting operations.
Innovation Solution
A control unit is implemented to manage the clutches and electric machine operation, allowing the second clutch to be closed during purely electric driving, enabling the internal combustion engine to assist briefly for seamless torque transmission and gear changes, thus utilizing all gears efficiently even with the electric machine attached to only one sub-transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the electric machine is attached to only one sub-transmission, then the installation space is reduced, but the usage flexibility and gear utilization for purely electric driving are limited
Solution Approach 1:
The patent makes the single sub-transmission to which the electric machine is attached serve multiple functions by enabling it to provide torque for all gears through the double clutch transmission. The electric machine, though physically connected to only one sub-transmission, becomes functionally universal by being able to power both odd and even gears through clutch coordination, thereby achieving multi-functionality without requiring physical attachment to both sub-transmissions.
Solution Approach 2:
The double clutch transmission acts as an intermediary mechanism that enables the electric machine to reach and power both sub-transmissions. By closing the second clutch, the electric machine's torque can be transmitted through the first sub-transmission to the even gears, while the first clutch enables direct connection to odd gears. This intermediary mechanism resolves the contradiction between limited physical attachment and expanded functional capability.
2Device complexity
If the electric machine is attached to only one sub-transmission, then the installation is simplified, but torque interruptions occur during shifting operations
Solution Approach 1:
The control unit performs preliminary actions by pre-coordinating clutch engagement and disengagement sequences before shifting operations. By managing the timing of clutch transitions and electric machine torque delivery in advance, the system ensures that torque is continuously available during gear shifts, preventing interruptions while maintaining the simplified single-attachment configuration.
Solution Approach 2:
The patent ensures continuous torque transmission during shifting operations by coordinating the clutches and electric machine to maintain uninterrupted power delivery. The control unit manages the transition between clutches and sub-transmissions in such a way that the useful action of torque transmission continues without interruption, even though the electric machine is physically attached to only one sub-transmission.
3Adaptability or versatility
If the second clutch is closed during purely electric driving, then all gears can be utilized for electric driving, but the internal combustion engine is driven by the electric machine which consumes additional energy
Solution Approach 1:
The patent dynamically manages clutch engagement and electric machine operation based on driving conditions and gear requirements. The control unit adjusts the degree of coupling of the clutches and the operation of the electric machine in real-time, closing the second clutch only when needed for purely electric driving in even gears, and opening it when the internal combustion engine is running or when odd gears are required. This dynamic adaptation minimizes energy consumption while maintaining full gear utilization capability.
Data Source
AI summary
A hybrid drive includes a control unit, an internal combustion engine, an electrical machine and a dual clutch transmission having an output shaft. The dual clutch transmission includes a first sub-transmission and a second sub-transmission, each couplable to the output shaft. A drive shaft of the internal combustion engine is couplable to a first input shaft of the first sub-transmission via a first clutch and to a second input shaft of the second sub-transmission via a second clutch. The control unit is configured to permit the second clutch to be closed even when the hybrid drive is being operated purely electrically so that the driveshaft of the internal combustion engine is driven by the electrical machine. A control unit and a method for operation of a hybrid drive are also provided.