Power-split hybrid powertrain planetary gear torque synthesis
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Solution Overview
Problem
Current all-wheel-drive hybrid vehicles face challenges in efficiently combining torque outputs from multiple power-sources to achieve optimal propulsion, particularly in configuring a powertrain that can provide on-demand all-wheel-drive capabilities while maintaining flexibility and efficiency.
Innovation Solution
A power-split hybrid powertrain is designed with a planetary gear-set and torque-transmitting devices that allow for selective connection of power-sources to a transmission assembly, enabling independent or combined operation of power-sources for each axle, utilizing a first and second power-source, such as an internal combustion engine and a motor-generator, with a transmission assembly that can be either multi-speed automatic or continuously variable.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single engine is used to propel the vehicle, then the powertrain structure is simple, but the vehicle cannot achieve optimal propulsion efficiency and on-demand all-wheel-drive capabilities
Solution Approach 1:
The patent combines multiple power sources (internal combustion engine and electric motor) with a planetary gear set into a unified power-split hybrid powertrain. The planetary gear set integrates the torque outputs from both power sources, allowing them to work together as a single coordinated system rather than separate independent systems, thus achieving all-wheel-drive capability without proportionally increasing overall system complexity
Solution Approach 2:
The planetary gear set serves multiple functions simultaneously: it combines torque from different power sources, enables power splitting between front and rear axles, and provides both two-wheel-drive and all-wheel-drive modes. This multi-functionality allows the powertrain to achieve adaptability for different driving conditions without requiring completely separate systems for each function
2Productivity
If multiple power-sources are used independently on different axles, then on-demand all-wheel-drive propulsion is achieved, but the configuration flexibility and torque combination efficiency are limited
Solution Approach 1:
The planetary gear set acts as an intermediary mechanism between the multiple power sources and the transmission assembly. It mediates the torque combination process by mechanically integrating torques from different power sources through its gear nodes, enabling efficient torque synthesis while maintaining configuration flexibility through selective connection of power sources to different axles
Solution Approach 2:
The powertrain is segmented into independent power-source modules that can be selectively connected to different axles through the planetary gear set. This segmentation allows flexible configuration where power sources can operate independently or in combination, optimizing torque distribution efficiency while maintaining adaptability for various driving scenarios
Data Source
AI summary
A power-split hybrid powertrain for a vehicle includes a first power-source configured to generate a first output torque, a second power-source configured to generate a second output torque, and a transmission assembly having a transmission input member. The powertrain also includes a planetary gear-set having first, second, and third nodes, wherein each of the three nodes is operatively connected to a separate one of the first power-source, second power-source, and transmission input member. The powertrain additionally includes a housing configured to retain the planetary gear-set. Also, the powertrain includes a first torque-transmitting device configured to selectively connect to the housing the node that is operatively connected to the first power-source. Furthermore, the powertrain includes a second torque-transmitting device configured to selectively connect the node that is operatively connected to the first power-source to the node that is operatively connected to the second power-source.