Dual-Pump Hydraulic Circuit for Hybrid Drivetrain Pressure Continuity
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Solution Overview
Problem
Existing hydraulic fluid preparation systems for hybrid drive trains, particularly in dual-clutch transmissions, face challenges in meeting the unique requirements of hybrid drive trains, including efficient pressure generation and fluid distribution across various components, especially during phases where the primary pump is shut down or pressure is insufficient.
Innovation Solution
A hydraulic circuit utilizing two pressure generators, one driven by an internal combustion engine and the other by an electric motor, with a central pressure line and priority circuits to manage pressure distribution, ensuring continuous hydraulic fluid supply to critical components even when the primary pump is not operational.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single pump is used in the hydraulic system, then the device complexity is reduced, but the reliability deteriorates because the pump cannot operate independently when the internal combustion engine is shut down
Solution Approach 1:
The hydraulic system is segmented into two independent pump units: a first pump unit driven by the internal combustion engine and a second pump unit driven by an electric motor. Each pump unit has its own drive mechanism, allowing independent operation. This segmentation ensures that when the internal combustion engine is shut down, the second pump unit can continue to supply hydraulic fluid, maintaining system reliability without requiring a completely complex redundant system.
Solution Approach 2:
The system changes the operational parameters of the pump units based on the operating phase of the internal combustion engine. During normal operation, both pumps may operate together. When the internal combustion engine is shut down, the control unit activates only the second pump unit, adjusting its operational parameters to maintain sufficient hydraulic fluid supply. This parameter adjustment allows reliable operation without constant full-system complexity.
2Reliability
If two pumps are used to ensure continuous hydraulic supply, then the reliability is improved, but the device complexity increases due to additional components and control mechanisms
Solution Approach 1:
The second pump unit is designed with multi-functionality to serve both as a primary pump during internal combustion engine shutdown phases and as a supplementary pump during normal operation. This universal design reduces the need for completely separate dedicated systems, thereby managing complexity while ensuring reliability. The control unit manages the functional switching between different operational phases.
Solution Approach 2:
The control unit automatically manages the operation of the two pump units based on the operating phase detection of the internal combustion engine. The system performs self-service by autonomously switching between pump configurations without requiring manual intervention, thereby managing the complexity of dual-pump operation through automated control while maintaining continuous reliable hydraulic supply.
3Use of energy by moving object
If the primary pump is shut down during certain operating phases, then the energy consumption is reduced, but the hydraulic fluid supply becomes insufficient without a secondary pressure source
Solution Approach 1:
The control unit is configured to activate the second pump unit in advance or simultaneously when the internal combustion engine is shut down, ensuring that hydraulic fluid supply is maintained without interruption. This preliminary action prevents any potential supply deficiency that might occur during the transition phase when the primary pump is deactivated, thereby maintaining sufficient hydraulic fluid flow rate while reducing energy consumption during engine shutdown phases.
4Adaptability or versatility
If a dual pump system is implemented, then the adaptability to hybrid drive train requirements is improved, but the ease of manufacture deteriorates due to increased system complexity
Solution Approach 1:
The hydraulic system is divided into modular pump units with distinct drive mechanisms, allowing each unit to be manufactured and tested independently before integration into the hybrid drive train. This segmentation facilitates adaptability to different hybrid drive configurations while managing manufacturing complexity through standardized modular components that can be assembled systematically.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution enables efficient and reliable hydraulic fluid supply to hybrid drive trains, ensuring continuous operation and improved fuel efficiency by decoupling pressure generation and allowing independent operation of each pump, thus addressing the limitations of existing systems.
Implementation Method 1
a first pump unit (5, 205, 405, 605, 805, 1005, 1205, 1405, 1605), in particular a mechanically operated pump unit, which can be driven using a first drive source (131) of the drive train (2500) and a second pump unit (7, 207, 407, 607, 807, 1007, 1207, 1407, 1607), in particular an electrically operated pump unit
Data Source
Figure 1
Figure 2A
Figure 2B
AI summary
The present invention relates to a hydraulic circuit for providing hydraulic medium with, inter alia, pressurisation of a hydraulic medium which can be used, for example, in a motor vehicle as a fluid of a gearing control system of a hybrid drive train. The present invention also relates to a method of using two pressure sources, e.g. two pumps, to provide hydraulic medium to different consumers and different cooling and/or lubricating points, in particular in a hybrid drive train. Depending on the design of the hybrid drive train, the internal combustion engine can sometimes be completely shut off although the vehicle is still driving. At least in this phase, but also in cases in which the volumetric flow and/or hydraulic pressure generated by the first pressure generator is insufficient, the second pressure generator can provide the necessary volumetric flow and/or the additional hydraulic medium under pressure. Depending on consumption requirements and/or the demand on the supply, priority circuits can then be present for both pressure generators in the hydraulic circuit.