Variable Displacement Vane Pump Eccentricity Control
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Solution Overview
Problem
Existing variable displacement lubricant vane pumps for internal combustion engines are complex and lack simplicity in controlling different set lubricant pressures, often requiring intricate hydraulic control systems and solenoid-operated valves.
Innovation Solution
A variable displacement lubricant vane pump design featuring a static pump housing with a shiftable control ring and rotatable pump rotor, utilizing a control ring preload spring and separate hydraulic safety and adjustment control chambers, along with an electric adjustment valve to control eccentricity and pressure, ensuring reliable and precise pressure regulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a complex hydraulic control valve system is used to control pump outlet pressure, then pressure control capability is improved, but device complexity increases
Solution Approach 1:
The control system is segmented into two independent control chambers: a safety control chamber that provides basic pressure control, and an adjustment control chamber that enables precise pressure adjustment. This segmentation allows each chamber to perform its specific function with simpler mechanisms, reducing overall system complexity while maintaining reliable pressure control capability.
Solution Approach 2:
The invention introduces an electric adjustment valve as an intermediary component that selectively connects the adjustment control chamber to the pressurized lubricant supply. This intermediary mechanism simplifies the control system by replacing complex hydraulic control valves with a more straightforward electrically actuated valve, reducing device complexity while preserving pressure control functionality.
2Measurement precision
If multiple control chambers are used for pressure control, then pressure regulation precision is improved, but device complexity increases
Solution Approach 1:
The control system divides pressure regulation into two distinct stages handled by separate chambers: the safety control chamber establishes basic pressure control, while the adjustment control chamber provides fine-tuned pressure adjustment. This segmentation enables precise pressure regulation without requiring a single overly complex control mechanism.
Solution Approach 2:
The adjustment control chamber is designed to be selectively pressurized through the electric adjustment valve, allowing the system to automatically switch between basic safety control and precise adjustment modes based on operational requirements. This self-service mechanism reduces complexity by eliminating the need for continuous complex hydraulic control.
3Productivity
If the control ring is preloaded into high eccentricity position, then pump displacement is maximized, but pressure control flexibility is reduced
Solution Approach 1:
The control ring is designed with dynamic positioning capability, allowing it to shift between high eccentricity position (maximum displacement) and low eccentricity position (pressure control mode). The control ring preload spring maintains the ring in the high eccentricity position for maximum pump displacement, while the safety control chamber and adjustment control chamber can selectively shift the control ring to the low eccentricity position for precise pressure regulation, providing both high productivity and pressure control flexibility.
Solution Approach 2:
The system changes the operational parameters of the control ring by utilizing the safety control chamber and adjustment control chamber to shift the control ring between two distinct eccentricity states. This parameter change enables the pump to switch between maximum displacement mode and precise pressure control mode, achieving both high productivity and adaptability.
4Reliability
If a fail-safe mechanism is implemented to prevent over-pressure, then safety is improved, but device complexity increases
Solution Approach 1:
The safety control chamber is pre-configured to receive pressurized lubricant and automatically shift the control ring into the low eccentricity position when pressure exceeds safe limits. This preliminary safety mechanism is built into the system architecture, providing fail-safe protection against over-pressure without requiring additional complex control components or intervention systems.
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 provides a simple and effective means to control lubricant pressures, ensuring reliable operation and precise pressure regulation, even at engine startup, with a fail-safe mechanism to prevent over-pressure and adaptive control based on lubricant temperature.
Implementation Method 1
A control ring preload spring is provided for preloading and pushing the shiftable control ring into the high eccentricity position
Implementation Method 2
The pump is provided with a hydraulic safety control chamber causing the shiftable control ring to move against the control ring preload spring into the low eccentricity position. The safety control chamber is directly and constantly loaded and pressurized with the lubricant having the pump outlet pressure.
Implementation Method 3
The adjustment control chamber is selectively pressurized with pressurized lubricant having an over-atmospheric pressure. The adjustment control chamber is selectively pressurized via an electric adjustment valve
Data Source
Figure 1
Figure 2
AI summary
The invention refers to a variable lubricant vane pump (20) for providing pressurized lubricant with a pump outlet pressure (P0), with a static pump housing (22), a shiftable control ring (24) and a rotatable pump rotor (26) comprising several rotor vanes (27) rotating within the control ring (24), the control ring (24) being shiftable with respect to the pump rotor (26) to thereby vary the eccentricity of the control ring (24) with respect to the pump rotor (26) for controlling the volumetric pump performance. The vane pump (20) further comprises: a control ring preload spring (36) preloading and pushing the shiftable control ring (24) into the high eccentricity direction (h), a hydraulic safety control chamber (40) causing the shiftable control ring (24) to move against the control ring preload spring (36) and being directly and constantly pressurized with the lubricant having the pump outlet pressure (PO), a separate hydraulic adjustment control chamber (42) causing the shiftable control ring (24) to move against the control ring preload spring (36) and being selectively pressurized with pressurized lubricant having an over-atmospheric pressure (PG), an electric adjustment valve (50) for selectively directing pressurized lubricant having the over-atmospheric pressure (PG) to the adjustment control chamber (42), and a calibrated hydraulic channel (46) directly connecting the adjustment control chamber (42) with atmospheric pressure (PA), the effective hydraulic cross sectional area being less than 5,0 mm².