Dual-Motor Planetary EV Powertrain for Torque Vectoring
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Solution Overview
Problem
Electric vehicle powertrains face challenges in improving fuel efficiency and achieving high-performance traveling with efficient torque vectoring, as existing systems struggle to optimize motor operating points and effectively distribute torque between driving wheels.
Innovation Solution
A powertrain apparatus featuring a planetary gear set with three rotation elements, where two motors are connected to different elements of the gear set, and a synchronizer mechanism allows selective engagement and disengagement between the driveshaft and motors, enabling efficient power combination, torque vectoring, and high-torque operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If two motors are connected to different rotation elements of the planetary gear set, then fuel efficiency is improved by optimizing motor operating points, but device complexity increases due to the additional clutch mechanisms and synchronizer required
Solution Approach 1:
The powertrain system is segmented into two independent motor units (first motor connected to ring gear, second motor connected to sun gear) that can operate independently or in combination. This segmentation allows each motor to be optimized for specific operating conditions, improving overall fuel efficiency while the modular structure manages complexity through functional separation
Solution Approach 2:
The synchronizer mechanism provides dynamic reconfiguration of the powertrain, allowing the system to switch between different operational modes (e.g., series-parallel hybrid mode, parallel hybrid mode, or independent motor operation). This dynamic adaptability enables optimization of motor operating points across varying vehicle conditions, improving fuel efficiency while the synchronized control manages the complexity of multiple connection states
2Adaptability or versatility
If a synchronizer is added to selectively connect or disconnect between the driveshaft and second motor, then torque vectoring capability is improved, but device complexity increases
Solution Approach 1:
The synchronizer acts as an intermediary mechanism between the second motor and the driveshaft, enabling selective engagement and disengagement. This intermediary component facilitates torque vectoring by allowing independent control of torque distribution to different wheels, while its integrated design within the existing planetary gear structure minimizes the increase in overall device complexity
Solution Approach 2:
The synchronizer serves multiple functions: it enables torque vectoring by selectively connecting the second motor to the driveshaft, facilitates mode transitions in the hybrid powertrain, and provides a neutral state where neither connection is active. This multi-functionality improves adaptability while consolidating control mechanisms, thereby managing device complexity
3Power
If the second motor is directly connected to the third rotation element (sun gear), then high-performance traveling is enabled by maximizing torque delivery, but loss of energy increases during mode transitions due to frequent engagement and disengagement
Solution Approach 1:
The synchronizer is designed with pre-positioned clutch mechanisms that can be engaged or disengaged in advance of required mode transitions. This preliminary preparation allows for smoother transitions with reduced energy loss, while the direct connection between the second motor and sun gear ensures maximum torque delivery is ready when needed for high-performance traveling
Solution Approach 2:
The powertrain system maintains continuous useful action by ensuring that at least one motor remains connected to the drivetrain during mode transitions. The synchronizer manages transitions in a way that minimizes interruption of torque delivery, reducing energy losses during switching while maintaining the direct connection capability for maximum torque when required
Data Source
AI summary
A powertrain apparatus for an electric vehicle, includes a planetary gear set including three rotation elements, a first motor connected to a first rotation element of the planetary gear set, a differential engaged to a second rotation element of the planetary gear set, a second motor connected to a third rotation element of the planetary gear set, and a synchronizer configured to selectively connect or disconnect between a driveshaft coupled to one side of the differential and the second motor and to selectively connect or disconnect between the second rotation element of the planetary gear set and the third rotation element of the planetary gear set.