Hybrid Multi-Mode PTO Torque Integration
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Solution Overview
Problem
Conventional power take-off systems in vehicles, such as agricultural tractors, are limited in their ability to seamlessly integrate torque from both internal combustion engines and electric motors, restricting their operational modes and efficiency across different applications.
Innovation Solution
A hybrid multi-mode power take-off system incorporating an internal combustion engine, two reversible electric machines, an epicyclical gear train, and an electronic control unit that manages clutches and energy transfer between the machines to enable various operating modes, including mechanical, electric power generation, and continuous variable transmission (CVT) modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional power take-off system with a single combustion engine is used, then the system structure is simple, but the operational flexibility and ability to integrate multiple torque sources is limited
Solution Approach 1:
The patent combines a combustion engine with multiple electric machines (motor and generator) into a hybrid power take-off system. The combustion engine and electric machines are merged through a power transmission system with epicyclical gear trains, allowing multiple torque sources to work together. This merging enables operational flexibility by selecting different operating modes (combustion-only, electric motor assistance, regenerative braking) while managing system complexity through integrated control.
Solution Approach 2:
The power take-off system is designed with multi-functionality to handle diverse operational requirements. The combustion engine can operate alone or with electric machine assistance, the epicyclical gear trains enable different speed/torque combinations, and the system can function in multiple modes (power transmission, electric motor drive, regenerative energy recovery). This universality allows a single system to adapt to various agricultural implement requirements without needing separate dedicated systems.
2Power
If a hybrid system with multiple electric machines and epicyclical gear trains is implemented, then torque integration from multiple sources is enabled, but the device complexity increases
Solution Approach 1:
The power transmission system is segmented into multiple independent epicyclical gear train sets, each capable of handling specific torque requirements. The first and second epicyclical gear trains are arranged in parallel, allowing torque from the combustion engine and electric machines to be distributed through different pathways. This segmentation enables complex torque integration while maintaining manageable complexity by dividing the transmission function into modular segments.
Solution Approach 2:
The epicyclical gear trains act as intermediary mechanisms between the power sources (combustion engine, electric machines) and the PTO shaft. These gear trains mediate the torque and speed relationships, enabling smooth power integration from multiple sources. The intermediate gear mechanisms transform and combine torques from different sources, reducing the complexity of direct coupling while achieving effective torque integration.
3Adaptability or versatility
If continuous variable transmission (CVT) modes are added to the power take-off system, then the adaptability to different operating conditions improves, but the device complexity increases
Solution Approach 1:
The system incorporates dynamic operating modes including CVT functionality through the epicyclical gear trains. The gear ratios can be continuously varied by adjusting the engagement of different clutch elements and brake elements, enabling smooth transition between operating modes. This dynamic capability allows the system to adapt to varying load conditions and implement requirements while the control system manages complexity through electronic control of the variable transmission elements.
Solution Approach 2:
The power take-off system changes operational parameters (speed ratio, torque distribution, power flow direction) to achieve different operating modes. By varying the engagement state of clutches and brakes, and adjusting the epicyclical gear train ratios, the system can operate in multiple modes (direct drive, CVT mode, regenerative mode). This parameter-based control enables adaptability to different conditions while managing complexity through parameter adjustment rather than mechanical reconfiguration.
Data Source
AI summary
A hybrid multi-mode power take off system (PTO) installed on a vehicle includes an internal combustion engine, a first electric reversible electric machine, a second electric reversible electric machine and one epicyclical gear train connectable with the engine and the first and second reversible electrical machines using a number of clutches. An electronic control unit controls the closure/opening of clutches to implement different operating modes. The electronic control unit is configured to control the transfer of energy between the first and the second reversible electric machines when one reversible electric machine is operating as a motor and the other is operating as a generator.