Positive Displacement Pump Unloading Plate for Parasitic Loss Reduction
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Solution Overview
Problem
Existing fluid management systems in vehicles experience parasitic energy losses due to excess fluid flow, which is not converted into functional energy, particularly in transfer pumps, even when the engine is idling, and existing solutions to reduce these losses are costly and complex.
Innovation Solution
A positive displacement pump with an unloading device, such as a resiliently biased plate, that moves away from the pumping gears upon pilot pressure application, creating an open chamber to reduce pressure development and parasitic losses, thereby optimizing fluid transfer without additional costly devices or complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a positive displacement pump is used to transfer hydraulic fluid, then fluid transfer function is achieved, but parasitic energy losses occur due to excess fluid flow returning to reservoir
Solution Approach 1:
The pump incorporates a movable unloading plate that dynamically adjusts the pump chamber volume based on system pressure requirements. When pressure is needed, the plate positions to create a sealed chamber for fluid transfer; when pressure is not needed, the plate moves to an unloading position that opens a bypass passage, allowing the pump to continue rotating without building pressure and thus eliminating parasitic energy losses.
Solution Approach 2:
The pump changes the physical parameter of chamber volume dynamically through the movable unloading plate. By varying the chamber volume from a sealed state (for pressure generation) to an open state (for unloading), the system optimizes energy efficiency while maintaining fluid transfer capability when needed.
2Loss of energy
If additional devices such as clutches or external unloading valves are added to reduce parasitic losses, then energy efficiency improves, but device complexity and cost increase
Solution Approach 1:
The unloading function is merged directly into the pump structure itself through the movable unloading plate integrated with the pump housing and drive shaft. This eliminates the need for separate external unloading valves or clutch mechanisms, reducing overall system complexity while achieving the same energy efficiency goals.
Solution Approach 2:
The pump system serves itself by using its own rotational motion and integrated movable plate to automatically unload excess fluid without requiring external control devices. The system self-regulates based on pressure differential, eliminating the need for additional complexity.
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
The solution effectively reduces parasitic losses in fluid management systems by allowing the pump to operate without developing pressure when not needed, saving power and fuel, and reducing operational and maintenance costs.
Implementation Method 1
A positive displacement pump with an unloading device, such as a resiliently biased plate, that moves away from the pumping gears upon pilot pressure application
Implementation Method 2
A bias element is disposed between the wall and the movable member
Data Source
AI summary
A fluid transfer pump that has a housing, a body portion movable within the housing between a first position and a second position, a gear coupled to the housing, a body cavity defined partially between the body portion and the housing, and an aperture defined in the housing that selectively provides a fluid to the body cavity. When the fluid is applied to the body cavity at or above a pilot pressure, the body portion is in the first position adjacent to the gear and when the fluid is applied to the body cavity at a fluid pressure lower than the pilot pressure, the body portion is in the second position and spaced from the gear.