Electric Drive Train Oil Supply with Switchable Auxiliary Pump
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing fluid supply systems for electric drive trains in motor vehicles face inefficiencies due to constant pump designs that can lead to undersupply or oversupply of oil, resulting in component failure, increased costs, and additional installation space requirements, particularly when trying to match oil requirements with varying drive speeds.
Innovation Solution
A device utilizing two mechanically driven hydraulic constant pumps with a fixed transmission ratio, where an auxiliary pump can be selectively switched on to adapt fluid delivery to meet the electric drive train's requirements, eliminating the need for a separate pump drive and allowing for efficient fluid management without excess oil.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a constant-displacement pump is used, then the pump structure is simple and cost-effective, but the fluid supply cannot adapt to varying drive speeds leading to insufficient or excessive oil supply
Solution Approach 1:
The single pump is divided into two separate constant-displacement pumps (first pump and second pump). Each pump operates independently with its own control mechanism, allowing the system to segment the fluid supply task and combine outputs flexibly to match varying demand without requiring each individual pump to be variable-displacement.
2Adaptability or versatility
If a variable-speed drive with electric motor is used to drive the pump, then the fluid supply can be precisely controlled, but the installation space and costs increase
Solution Approach 1:
The control functions of two pumps are merged through their common output to the hydraulic circuit. By coordinating the operation of two simple constant-displacement pumps, the system achieves variable fluid supply capability without requiring complex variable-speed drives or electric motors on each pump, thus reducing overall system complexity and installation space.
Solution Approach 2:
The system uses the mechanical energy from the drive shaft itself to drive both pumps directly, eliminating the need for separate electric motors. The pumps self-regulate their contribution to the hydraulic circuit through the control mechanism that directs fluid from either pump based on system requirements.
3Adaptability or versatility
If a variable displacement pump is used, then the fluid supply can be adjusted, but the cost lies between electric drive and fixed displacement pump without clear advantages
Solution Approach 1:
Instead of using a single complex variable-displacement pump, the system segments the function into two simpler constant-displacement pumps. This segmentation allows the system to achieve variable fluid supply by controlling which pump operates or how each contributes, using cheaper constant-displacement pump technology throughout.
4Duration of action of stationary object
If excess oil is supplied to the system, then the pump operates continuously, but overall efficiency decreases due to unused oil returning via restrictor and pressure rises causing leaks
Solution Approach 1:
The system dynamically adjusts the fluid supply by selectively activating or deactivating the second pump based on real-time hydraulic circuit requirements. This dynamic control prevents excessive fluid supply and the associated energy losses through restrictors, maintaining optimal pressure levels and preventing leaks while ensuring continuous operation when needed.
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 enhances overall efficiency, reduces costs, and minimizes installation space by ensuring sufficient fluid supply while minimizing excess fluid, decoupling fluid requirements from vehicle speed, and maintaining efficient lubrication and cooling.
Implementation Method 1
a first pump (10) designed as a hydraulic constant-displacement pump for pumping fluid from a fluid reservoir (40) to the electric drive train
Data Source
Figure 1~2
Figure 3~4
AI summary
The present invention relates to an apparatus (100) for supplying fluid to an electric drive train for a motor vehicle, preferably for cooling and lubricating a transmission (50) and/or for supplying oil to an electric motor of the electric drive train. The apparatus (100) comprises a main pump (10) designed as a hydraulic constant displacement pump for conveying fluid from a fluid reservoir (40) to the electric drive train. The apparatus (100) further comprises at least one auxiliary pump (20) designed as a hydraulic constant displacement pump. The main pump (10) and the auxiliary pump (20) are driven mechanically by the transmission (50) of the electric drive train in such a way that there is a fixed transmission ratio between a pump speed of the main pump (10) and a pump speed of the auxiliary pump (20), the auxiliary pump (20) being activatable as required by means of a controllable actuating device (30) for supplying fluid to the electric drive train.