Wide-Node Electro-Mechanical Drive Unit for Hybrid Powertrain
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Solution Overview
Problem
Hybrid vehicle powertrains face inefficiencies in torque and speed management due to the need for the internal combustion engine to operate in conjunction with electric motors, limiting the ability to achieve optimal vehicle propulsion across various speed ranges.
Innovation Solution
A wide-node electro-mechanical drive unit with a compound planetary gear arrangement and two motor/generators, allowing independent control of torque and speed, and incorporating a torque-transmitting device for efficient power distribution between the engine and electric motors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single electric motor is used in combination with the engine, then the device complexity is reduced, but the ability to independently control torque and speed is limited
Solution Approach 1:
The patent combines two motor/generators on a common rotating axis with a compound planetary gear arrangement to create a unified powertrain system that achieves independent torque and speed control while managing device complexity through integrated design
2Power
If the engine operates in conjunction with electric motors, then the power output is increased, but the efficiency is reduced due to inability to optimize across various speed ranges
Solution Approach 1:
The compound planetary gear arrangement dynamically adjusts gear ratios across multiple ranges, allowing the system to optimize the operational conditions of both the engine and electric motors at any given moment, thereby minimizing energy losses while maintaining high power output
Solution Approach 2:
The system changes operational parameters by varying gear ratios through the planetary gear sets, enabling the engine and motors to operate at optimal efficiency points across different vehicle speeds and load conditions
3Loss of energy
If a wide-range gear ratio spread is achieved, then the efficiency across all speed ranges is improved, but the device complexity increases
Solution Approach 1:
The patent employs nested planetary gear sets where smaller gear sets are integrated within larger ones, sharing common elements such as the common rotating axis and stationary members, thereby achieving wide gear ratio coverage while minimizing the number of discrete components
Data Source
AI summary
An electro-mechanical drive unit connectable with multiple power sources for launching and propelling a vehicle includes an output member, a stationary member, and a torque-transmitting device. The drive unit also includes a compound planetary gear arrangement having a first, second, third, and fourth junction point. The power sources include a first motor/generator and a second motor/generator. The first motor/generator and the second motor/generator are disposed on a common rotating axis. The second motor/generator is operatively connected to the compound planetary gear arrangement at the first junction point and the output member is operatively connected to the compound planetary gear arrangement at the second junction point. Additionally, the first motor/generator is operatively connected to the compound planetary gear arrangement at the fourth junction point. Furthermore, the torque-transmitting device is engageable to ground the third junction point to the stationary member.